Systematic design methodology and construction of UAV helicopters
外文翻译---注塑模具设计的一种智能型腔设计系统
International Journal of CAD/CAM V ol. 2, No. 1, pp. 69~75 (2002)An Intelligent Cavity Layout Design System for Injection Moulds Weigang Hu and Syed Masood*Industrial Research Institute Swinburne (IRIS), Swinburne University of Technology, Hawthorn, Melbourne, Australia 3122AbstractLayout Design System (ICLDS) for multiple cavityinjection moulds. The system is intended to assist mould designers in cavity layout design at concept design stage. Thecomplexities and principles of cavity layout design as well as various dependencies in injection mould design are introduced.The knowledge in cavity layout design is summarized and classified. The functionality, the overall structure and generalprocess of ICLDS are explained. The paper also discusses such issues as knowledge representation and case-based reasoningused in the development of the system. The functionality of the system is illustrated with an example of cavity layout designproblem.Keywords: Intelligent design, cavity layout design, injection mould design, case-based reasoning, design support system1. IntroductionIn manufacturing, the injection moulding is one of the most widely used production processes for producing plastic parts with high production rate and little or no finishing required on plastic products. The process consists of injecting molten plastic material from a hot chamber into a closed mould, allowing the plastic to cool and solidify and ejecting the finished product from the mould. For each new plastic product, the injection moulding machine requires a new injection mould. Design and manufacture of injection mould is a time consuming and expensive process and traditionallyrequires highly skilled tool and mould makers. An injection mould consists of several components, which include mould base, cavities, guide pins, a sprue, runners, gates, cooling water channels, support plates, slides and ejector mechanism [1]. Design of mould is also affected by several other factors such as part geometry, mould material, parting line and number of cavities per mould. With the advances in computer technology and artificial intelligence, efforts have been directed to reduce the cost and lead time in the design and manufacture of an injection mould. Injection mould design has been the main area of research since it is a complex process involving several sub-designs related to various components of the mould, each requiring expert knowledge and experience. Mould design also affects the productivity,mould maintenance cost, manufacturability of mould, and the quality of the moulded part. Most of the work in mould design has been directed to the application of expert systems, knowledge based systems and artificial intelligence to eliminate or supplement the vast amount of human expertise required in traditional design process. Kruth and Willems [2] developed an intelligent support system for the design of injection moulds integrating commercial CAD/CAM, a relational database and an expert system. Lee et. al. [3] proposed a systematic methodology and knowledge base for injection mould design in a concurrent engineering environment. Raviwongse and Allada [4] developed a neural networkbased design support tool to compute the mould complexity index to help mould designers to assess their proposed mould design on mould manufacturability. Kwong and Smith [5] developed a computational system for the process design of injection moulding based on the blackboard-based expert system and the case-based reasoning approach, which includes mould design, production scheduling, cost estimation and determination of injection moulding parameters. Britton et. al. [6] discussed the injection mould design from a functional perspective using functional design knowledge and a number ofknowledge libraries. Mok et. al. [7] developed an interactive knowledge-based CAD system for injection mould design incorporating computational, knowledge and graphic modules. Several studies have also been made on improving the design of specific components of an injection mould. Ong et. al. [8] developed a knowledge-based and objectoriented approach for the design of the feed system for injection moulds, which can efficiently design the type, location and size of a gating system in the mould. Irani et. al. [9] also developed a software system for automatic design of gating and runner systems for injection moulds and provide evaluation of gating design based on specified performance parameters. Nee et. al. [10] proposed a methodology for determination of optimal. parting directions in injection mould design based on automatic recognition and extraction of undercut features. Chen and Chou [11] developed algorithms for selectinga parting line in mould design by computing the undercutvolumes and minimising the number of undercuts. Parkand Kwon [12] worked on the design of cooling systemsin injection moulds and proposed an optimal designbased on thermal analysis and design sensitivity analysisof the cooling stage of the injection moulding process.Lin [13] worked on the use of gate size and gate position as the major parameters for simulated injection mould performance prediction. One area in injection mould design, which has received little attention, is the design of cavity layout in a multiple cavity injection mould. Cavity layout design affects the whole process of injection moulding directly, since it is one of the most important phases in mould design process. Consideration of cavity layout design in injection mould at concept design stage will improve the quality of injection moulded products because it is associated with the determination of many key factors affecting the design and quality of mould. Such factors include number of cavities; parting line; type of mould; type and position of gate; runner system; cooling system and ejection system. Some of these factors are difficult to build astrue mathematical models for analysis and design. This paper presents the development of a design support system, called Intelligent Cavity Layout Design System (ICLDS), for multiple-cavity injection moulds based on knowledge based and object oriented approaches. It uses the case-based and ruled-based reasoning in arriving at the layout solution [14]. It is based on the commercial software system named “RETE++”, which is an integrated development platform for customers to develop their own knowledge-based systems [15]. The objective is to make full use of available techniques in artificial intelligence in assisting mould designers at concept design stage. 2. Cavity Layout Design in Injection MouldsCurrent practice for injection mould design, especially cavity layout design, depends largely on designers’ experiences and knowledge. It would therefore be desirable to use knowledge engineering, artificial intelligence and intelligent design techniques in generating an acceptable cavity layout design in injection mould accurately and efficiently. In mould design, most of patterns of cavity layout and rules and principles of cavity layout design can also be easily represented in the form of knowledge, which can be used in most of knowledge-based design systems. the criteria to select the suitable layout pattern for design are mainly dependent on working environments, conditions and requirements of customer and are mainly based on designer’s skill and experience. To make a choice of contradictory factors will rely obviously on designer’s knowledge and experiences. It is rather suitablefor intelligent design techniques to be used in systems designed for such situations, especially for routine or innovation design.Design of injection mould mainly involves consideration of design of the following elements or sub-systems:(1) mould type(2) number of cavities(3) cavity layout(4) runner system(5) ejector system(6) cooling system(7) venting(8) mounting mechanismMost of the elements are inter-dependent such that it is virtually impossible to produce a meaningful flow chart covering the whole mould design process. Obviously, in injection mould design, it is difficult for designer to monitor all design parameters. Cavity design and layout directly affects most of other activities.The application of advanced knowledge based techniques to assist designer in cavity layout design at conceptdesign stage will greatly assist in the development of a comprehensive computer-aided injection mould design and manufacturing system. Higher the number of cavities of mould, higher the productivity of the injection mould. But this may lead to difficulties with issues such as balancing the runners or products with the complicated cavity shapes, which in turn may lead to problems of mould manufacturability. It is also possible that the number of cavities and the pattern of cavity layout will influence the determination of parting line, type of gate, position of gate, runner system and cooling system. Most of the main activities of mould design are therefore linked to cavity layout design. The cavity layout design problem therefore depends upon a number of functionalities of the overall mould design system, which includes:(1) definition of design specifications includinganalysis and description of characteristics of(2) determination of mould type(3) determination of number of cavities(4) determination of orientation of product(5) determination of runner type and runnerconfiguration(6) determination of type and position of gate(7) cavity layout conceptual design(8) evaluation of ejection ability, manufacturingability and economic performances(9) determination of cooling system(10) graphic results display and output3. Structure of ICLDS and the Design ProcessThe structure of the Intelligent Cavity Layout Design System (ICLDS) is based on case-based reasoning andruled-based reasoning designed around the RETE++ The design process starts with the definition of design specifications. The ICLDS system retrieves similar cases from case base by computing the similarity between the cases and the new case. If the solution is satisfactory, then results are displayed graphically. If the solution is not satisfactory, then ICLDS will use rule-based reasoning with forward or backward chaining or a mixture of both to arrive at a solution. Ifthe solution is still unsatisfactory, then the user has to modify some of the initial design specifications. The use of case-based technology in the design process in ICLDS allows the user to obtain the solution(s) of design problem more quickly and flexibly. The structure of knowledge base and database used in the development of ICLDS is based on the underlying knowledge base and database structure from the RETE++ software system, which is a commercially available software development platform.4. Development of ICLDS4.1. Classifications of KnowledgeFor various logic and steps involved in layout design, there are different kinds of knowledge that needs to be described and represented in cavity layout design. The types of knowledge can be classified into five kinds based on object oriented (OO) concept as described below:(1) Design instance/case: previous design cases and current design instances(2) Relation: superclass-class-subclass relation, classinstance relation(3) Attribute: design variables, features, attributes of design problem(4) Rule: general design rules, design experiences(5) Procedure and/or model: numeric calculation, mathematical modeling, analysis, evaluation andprocedures.4.2. Knowledge RepresentationsTo describe each of these types of knowledge, the internal data structures of the ECLIPSE language, included in RETE++ inherently, can be used to make the object orientated representation of the design process as explained earlier. Some other considerations in knowledge representation are as follows:(1) For “design instance/case”, we combine “fact definition” and “relation definition” plus database and case base to represent it(2) The “attribute” are represented as instances of“template definition” and/or “relation definition”(3) For “relation”, we use “relation definition” to describe it(4) For “rule”, we combine “rule definition” and“rule set definition” to represent it(5) The “procedure/model” are defined by external routines using C++ language Furthermore, “goal definition” and “goal generation”techniques are used to fulfil backward chaining reasoning, and “case-based reasoning” is used to carry out casebased design.4.3. Case-based ReasoningCase-Based Reasoning (CBR) is dependent firstly on case retrieved. Case-based retrieval is based on “Similarity Metric”. Therefore, how to calculate the similarity is obviously the key technique in CBR, and it is described in detail as below. Similarity metric is a weighted distancefunction in a multi-dimensional space where each dimension corresponds to a field whose value is specified in the query (new case) and which has a non-missing value in the case being ranked. The distance between the case and the query (which corresponds to a point in this multi-dimensional space) is computed differently for ordinal and nominal fields. An ordinal field is a field whose values are ordered or sorted. A nominal field is one whose values represent qualitative information for which sorting makes no sense. In general, ordinal fields include dates, integers, and real numbers while nominal fields include Boolean, Symbols, and Text.关于CAD/CAM的国际性杂志注塑模具设计的一种智能型腔设计系统摘要：本文展示了注塑模具多腔设计的智能型腔设计的发展，这个系统可以帮助模具设计者提供流道设计的观念，介绍了复杂的型腔设计原则和多样的设计理念，以及型腔版面设计的概述、分类、功能，全面地构造和智能化腔孔版面设计的程序使用方法的解释说明。
Design Engineer and Design Methodology——设计工程师与设计方法中英文对照
Design Engineer and Design Methodology——设计工程师与设计方法1 What Makes a Good Design Engineer ? Is design an art form only to be practiced by those gifted with its talents, or is it a regimented discipline that can be learned? Virtually everything that humans do involves altering the environment around us, which is essentially what design is all about; thus every individual possesses the ability to design to some extent. While there are few Mozart’s in the history of the world, there are numerous musicians who play his music and enable us all to enjoy it. Each person must identify the area in which he feels promise, and must do the best job he can. It is true there is only one queen been in a hive, but without the workers even the queen cannot survive. In other words, be careful of your ego and always strive to improve your abilities.2 It is very difficult to teach people how to become creative design engineers because everyone thinks differently. There are often no clear solutions to a problem. Historical knowledge can also often be a powerful tool to help demonstrate how creative ideas are formed; unfortunately, a discussion of the history of machine tool development is beyond the scope of this book. Systematic methods of analysis and synthesis can be formulated to aid in development of ideas; however, these methods have often been blamed for stifling creativity. A good design engineer often uses systematic methods of analysis and synthesis in order to help evaluate wild and crazy conceptual ideas generated during the initial creative phase of problem solving.3 How can creativity be stimulated and enhanced ? Perhaps if this question could be answered with an equation, a computer program could be written that could design anything. Good design engineers usually think in terms of pictures instead of equations or if then else logic. Often, it seems as if daydreams are an inner manifestation of the creative urge within all individuals. The task of the design engineer, therefore, is to install enough reality into his or her memory to enable daydreams to produce useful solutions to real problems. One must also be able to keep a mental catalog of available building blocks and methods in which they can be manufactured and put together. The database must be open, so as to not preclude the development of new building blocks, while taking care to keep abreast of new technologies.4 A design engineer must also become good at identifying problems. Once a problem is identified, it will usually yield to an unending barrage of creative thought and analysis. High-priced consultants do not necessarily solve detailed problems;they identify the problems for others to solve. Identifying a problem requires careful detective work. In addition to solving and identifying problems, the design engineer must also learn to identify what the customer really needs, which is not necessarily what the customer thinks that he or she needs. This requires interactionwith marketing research groups, customers, and manufacturing personnel on a continuing personal basis.5 To keep his or her mind tuned, a good design engineer must always ask: “How does that work?” and “Why does that catch my eye?” regarding everything he or she sees in daily life. This will help to develop a feel for the needs and wants of people and the ability to make a realistic assessment of what is technologically feasible. It will also help the design engineer to develop a feel for color, form, texture, and proportion. By being observant, patient, and optimistic, a design engineer will become aware of what people buy and use. If the design engineer notices fault with something, chances are that others do, too, and thus money could be made by correcting the fault. Opportunity only knocks for those who listen, and it is hard to hear knocking when the radio is turned up too loud.6 In addition, although each engineer must understand the physics of operation of the machine, he or she must realize that the design process is itself a precision dynamic system. If each engineer understands the structure of the design process and what other members of the team have to do, he or she will be less likely to cause problems that adversely affect the project. Once attitudes such as “why should I bother with this detail because someone will catch it” beco me established, competitiveness is the next thing to be lost. Design engineers must feel a personal love for their work and the work of team.7 Formulating a Personal Design Methodology One of the founding fathers of machine tools, Henry Maudslay who was born in 1771, is credited with the development of the compound side, whose design principle is used on virtually every lathe in the world today. Although it is said that many of his inventions were described before by others in principle, it was Maudslay who reduced many ideas to practice. One of Maudslay’s fundamental contributions was to note that the extra cost of making a machine from metal, as opposed to wood, was recouped many times over in terms of the machine’s accuracy and life. Maudslay had several maxims which still serve as a set of basic guidelines for all types designs:1). Get a clear notion of what you desire to accomplish, then you will probably get it.2). Keep a sharp look-out upon your materials: get rid of every pound of material you can do without. Put yourself to the question, “ what business has it there?” Avoid complexities and make everything as simple as possible.3). Remember the get-ability of parts.Maudslay’s maxims can be used as a good foundation for just about any personal design methodology.8 Because many modern systems are often so complex, expertise is required in many different disciplines; hence often it is nearly impossible for one person alone to design an entire system. However, it is possible to be aware of the capabilities of other disciplines. This allows an individual or small group to develop a design plan for complex system.9 Although it is often said that “no matter what you design, somebody has already thought of it before, at least in principle,” this should not be accepted as a defeatist attitude but rather one of awareness. Continual updating of one’s mental memory banks with new knowledge about advances in all fields of engineering and science is a must if a design engineer is to remain competitive. This updating must be the cornerstone of every design engineer’s personal design methodology. Other than that, every design engineer has his or her own way of doing things, many aspects of which are borrowed from established methods. Some of these methods are discussed below.10 Designs can be categorized as being original, adaptive, or scaled. Original design means developing a new way of doing something (e.g., cutting with waterjets, as opposed to using a saw blade). Adaptive design means using technology developed for another task and adapting it to perform the task at hand (e.g., using lasers to sculpt wood). Scaled design means changing the size or arrangement of a design in order to accommodate a similar change in an existing process (e.g., design a bigger version of an existing machine). each of these types of design can be equally challenging and all require five basic steps:1) Task definition2) Conceptual design3) Layout design4) Detail design5) Design follow-up11 Task definition often starts with the customer or sales representative requesting the design department to provide a study regarding the feasibility, cost, and potential availability of a design to perform a specific function. In response to this request, thecompany’s best design engineers g et together to sketch out concepts. It is in the conceptual design phase that the functional relationships of components and the physical structure are usually defined. Once a few select conceptual designs are chosen, they are expanded in detail through layout design where preliminary sizing of components and calculations are made in order to produce rough assembly drawings of the conceptual designs. This enables more accurate feasibility and cost estimates to be developed. After modifying the required specifications and conceptual designs, the project’s feasibility can be determined, usually resulting in one design being chosen for detailing. The detail design phase is everything that follows in order to bring the design to life. Design follow-up involves activities such as the development of a maintenance plan and documentation, which often cause many design engineers to run and hide. However, if the design is not maintained , or if nobody can figure out how to use it, the design will not be used and design effort will have been wasted.12 Along each step of the design path, design engineers have to apply their own personal design methodology, which they must develop themselves. Whatever from the methodology takes, it should realize that no develop a design plan for complex system.12 Along each step of the design path, design engineers have to apply their own personal design methodology, which they must develop themselves. Whatever from the methodology takes, it should realize that no design engineer is an island. In general, the method should:1) Foster creativity. The design engineer should always start with wild, crazy, “what if” designs and if necessary scale back to more rational conventional solutions.The design engineer, however, must know when to turn off the wild, crazy, dreaming aspect often associated with generating conceptual designs, and proceed with a systematic consideration of one or two concepts that will lead to the detail design.2) Acknowledge the creativeness of others. A nor invented here (NIH) syndrome is unacceptable and has been the downfall of many a firm that was unwilling to adopt an outsider’s superior concept. There is no room for prejudice in design. One must take what exists, use it to its fullest potential, and then improve upon it.3) Do not depend on luck or ignore a problem in the hope that it will go away. A wishful attitude has killed many people and generated huge legal fees. Every detail from where to run electric lines and hydraulic hoses, to placement of the warning labels and nameplates, must be carefully considered.4) Be disciplined and well organized so the design can be passed onto others for detailing or completion. This requires knowing how to delegate authority to optimize utilization of an organization’s resou rces.5) Respect simplicity and the fundamental knowledge of how and why things work. This will hasten the convergence process for a design and will help prevent oversights such as placing a measuring element far away from the process to be measured (Abbe error). It will also lead to the minimizing of design cost, manufacturing cost, functional errors, and embarrassment.6). Continually subject designs to value analysis in an effort to reduce cost with an equal or increased level of quality. Not only must the design be subject to value analysis, but the manufacturing and sales must be considered as integral parts of a successful design process. Thus the design engineer must also be knowledgeable in production and marketing skills.13 When developing your own personal design methodology, also consider some of the following common methods used by design engineers to develop solutions to design problems:1). Persistent questioning. By always asking “Why?” and “Can it be made simpler and better?” You will be less likely to settle for less than best, or to overlook a possible improvement.2). Known solutions. By analyzing known solutions to existing similar problems, one can often find a wheel that exists without having to reinvent it. This method also includes systematic analysis of variations of known solutions.3). Forward chaining. Start with a sketch of the problem depicting what you hope to accomplish and then form an expanding tree of ideas.4). Backward chaining. Start with what you know the complete design must look like and then trace back through all the elements that lead to the final design and scale and modify them accordingly. This procedure is usually used to develop manufacturing or process plans.14 The array of products that are designed in the world is so varied and complex that it is nearly impossible to list a comprehensive generic design plan that incorporates these concepts for a generic product.1什么是好的设计工程师？设计艺术形式不仅是实行这些天赋的人才，或者是一个严格的纪律，可以学到了什么？几乎所有人类涉及改变我们周围的环境，这是主要的设计都是；每一个人拥有的能力设计在一定程度上。
面向计算机科学的数理逻辑系统建模与推理英文原版第二版教学设计
Teaching Design of Modeling and Reasoning in Mathematical Logic for Computer Science IntroductionMathematical Logic is a fundamental branch of mathematics thatstudies reasoning and inference. It provides a systematic approach to reasoning and problem-solving that can be applied to various fields, including computer science. In this teaching design, we will be usingthe second edition of the English original text entitled Modeling and Reasoning with Mathematical Logic: An Introduction for Computer Scientists.The m of this teaching design is to introduce students to the basics of mathematical logic and its applications to computer science. We will cover topics such as propositional logic, predicate logic, set theory, and proofs. In addition, we will use examples and exercises that are relevant to computer science, such as programming language semantics, databases, and artificial intelligence.Course ObjectivesUpon completion of this course, students should be able to:1.the principles of mathematical logic and its applications in computer science.2.and reason about various problems usingpropositional and predicate logic. 3.the basics of set theory and itsuse in modeling problems. 4.simple theorems using mathematical reasoning.5.the principles of mathematical logic in programming language semantics, database design, and artificial intelligence.Course OutlineChapter 1: Introduction to Mathematical LogicIn this chapter, we will provide a brief introduction tomathematical logic and its history. We will also introduce the syntaxand semantics of propositional logic, including truth tables and logical equivalence.Chapter 2: Reasoning with Propositional LogicIn chapter 2, we will cover the basics of reasoning withpropositional logic, including deductions, proofs, and the resolution method. We will also use examples and exercises that are relevant to computer science, such as circuit design and programming language semantics.Chapter 3: Predicate LogicChapter 3 introduces predicate logic, which extends propositional logic by adding quantifiers and predicates. We will cover the syntax and semantics of predicate logic, as well as the first-order logic. We will also use examples and exercises that are relevant to computer science, such as databases and artificial intelligence.Chapter 4: Set TheoryChapter 4 introduces the basics of set theory, including set operations, relations, and functions. We will cover the axiomatic foundations of set theory, as well as the ZFC axioms. We will also useexamples and exercises that are relevant to computer science, such as programming language semantics and databases.Chapter 5: Reasoning with Sets and RelationsIn chapter 5, we will apply our knowledge of set theory andpredicates to reason about sets and relations. We will cover basic set operations, equivalence relations, and partial orders. We will also use examples and exercises that are relevant to computer science, such as database normalization and graph algorithms.Chapter 6: Proofs and TheoremsChapter 6 introduces the basics of mathematical proofs and theorem proving. We will cover various proof techniques, including direct proofs, proofs by contradiction, and mathematical induction. We will also use examples and exercises that are relevant to computer science, such as program verification and testing.Teaching MethodologyThe teaching methodology will include lectures, in-class problem-solving, and assignments. In the lectures, we will cover the theory and principles of mathematical logic and their applications in computer science. In the problem-solving sessions, we will work through examples and exercises to reinforce the concepts covered in the lectures. Finally, the assignments will be designed to test students’ understanding of the course material.AssessmentThe assessment will be based on assignments (40%), mid-term examination (30%), and final examination (30%).ConclusionIn conclusion, this teaching design provides a systematic approachto teaching mathematical logic and its applications in computer science. By the end of the course, students will have a solid foundation in mathematical logic that they can apply to various areas in computer science.。
instructionaldesign教学设计methodologyn方法学
形成性评价是每个ADDIE阶段的一部分，并且
测定每个阶段的效果和质量。终结性评价则评 判整个课程的价值和关注学习者可测量的结果。
Identify
three levels of course knowledge, skills and attitudes: core knowledge, useful knowledge, and customized/advanced knowledge, including challenging unsolved problems.
教学设计是为教学开发、实施、评价和情景维
护建立详细规范的科学，有助于各种复杂程度 和大小科目的学习。
Formative
evaluation is part of each ADDIE phase and determines effectiveness and quality of each stage. Summative evaluation judges the worth of the entire course and will focus on measurable learner outcomes.
信奉vi. 拥抱
synchronousadj. behaviorism
同时的，[物] 同步的
n.行动主义，行为学派 建构主义
constructivismn. authenticadj. inertian.
可信的
惯性，惯量
In
the fifty years that followed, ID has become the standard for producing excellent training in both the military and corporate realms, as well as textbook authoring and development of computer-based learning materials.
不同类型的研究 Different types of research 英语作文论文
不同类型的研究Types of research Different types of researchHello friend how are you? Today with the help of this article I am going to put some light on a very interesting and mind-boggling part of academics writing. I am talking about Types of research. You read it right. Today we are going to discuss more on this topic in a detailed manner. Research is a familiar word for the students who are doing post-graduation or PhD. Also to all my science-loving friends, you must be familiar with this word from a long time.Research and science especially go hand in hand. When we talk about science, the other word which comes in our mind is research. Research helps in scientific discoveries. Every new medicine is a product of long research. But the word research is now not limited to the field of science only. In almost every discipline different types of research are present currently. Research is a vital part of the development and discoveries of new things in all academic subjects. From science to psychology every subject now has some and some kind of research work in it.So today with the help of this article I am going to talk about:What Research is?Two main types of researchDifference types of research and a thin line of demarcation in themWhat research is not?Why is research helpful to students?What Research is?Research is a systematic inquiry on a specific topic. When you want to get the information on a particular topic, you take a process to enhance your knowledge. There are different types of research out there. But it depends on you what type you prefer.A lot of casual researches these days begins with a Google query (“Who, what, how?”) and you will end on a Wiki page. Getting informative data is comparatively easy. The knowledge already exists. You just have to search a trustworthy source for it. Assessing credibility is the hard part.Why is research helpful to students?This question may come to your psyche while you are in your academic career. You often think that what is a need of doing a research work? Why universities want us to carry out research. Then read below to find your answer.Answer of the question raised aboveIt teaches them to inquire about things that are said and done, rather than accepting or rejecting them at face value;It teaches them to gather evidence for things that are said and done, before making decisions;Research teaches them how to gather that evidence, in ways that minimize bias;It teaches them to consider alternatives before making decisions;in the process, they learn to evaluate things that are said and done from the weaknesses and strengths of those arguments or events;therefore it increases the chances that their decisions are going to be helpful/realistic ones;It increases the chances that any advice that the student gives will be well-judged;It demonstrates that the experience of doing real-world research is different from the idea of how that research will go into the researcher’s imagination, and this insight is valuable. Humans are very prone to constructing ideas from nothing other than what is in their heads, and being able to compare that to reality is important for living a coping life.So I hope you got your answer to the question of why you need to carry out research. Lots of students find research work difficult. They often get puzzled in this and end up in vain. Some students face selecting research approach from different types of research.Two main types of ResearchPure researchis carried out to generate new human knowledge. To uncover new facts or fundamental principles you need pure research. The researcher wants to advance in a specific field, for example, neuroscience, by answering a specific question, such as “Why do humans sleep?” Pure research is based on experimentation and observation. The results of your research are published in peer-reviewed journals. This isscience. Rigorous standards and methodologies exist to preserve objectivity and ensure the credibility of conclusions. (Things get squishywhen corporations fund ostensibly pure research, as they frequently do.)Applied researchborrows ideas and techniques from pureresearch to serve a specific real-world goal. Goals are like creating a super soldier or improving the quality of hospital care or finding new ways to market any product. While ethics are as important, and methods can be more relaxed. By this, I meant changing the questions you ask while doing a study, or making the most of an imperfect sample grou p because you’re tight on time. Your research is successful only to the extent that it adds to the stated goal. As with pure research, sometimes you accidentallydiscover something valuable you weren’t even looking for, and that’s a fantastic bonus.Different types of research and a thin line of demarcation in themSo now you have understood about two main types of research in the above paragraph. But that is not enough. There are further types of research presentations. You may say these are the subdivision of above-mentioned types. Now you will learn about different types of research and basic difference in them.Generative vs. exploratory researchThis is the research you do before you know what you’re doing. This research leads to ideasand helps in def ining the problem. Don’t think of this as just the earliest research. Even if you’re working on a current product or service, you might be looking for ideas. You need ideas for additional features. Generative research includes interviews, reviewing existing literature, and field observation,Exploratory research, as the name says, intends to explore the research questions. It does not make to give conclusive or final solutions for the existing problems. Exploratory research is conducted with an aim to study a problem that does not have any solution yet.The research is done in order to understand the nature of the problem. It is not done to provide conclusive evidence. But it helps in the better understanding of the problem. When aresearcher conducts exploratory research, he/she should be willing to change his/her direction when new data reveals.Exploratory research never gives you the final or conclusive answers to your research questions. But it explores the research topic on different levels. It has been seen that exploratory research is an initial stage of research. Exploratory research provides a basis of conclusive research. It will help in making of research design, sampling methodology and data collection method. Exploratory research tackles new problems on which no research has been done.Descriptive vs. AnalyticalDescriptive research consists of surveys and fact-finding inquiries of various kinds. The major reason to carry out descriptive research is describing the state of affairs as it exists at present. When we do descriptive result in social science and business research, we use the term Ex post facto research for descriptive research work. The main feature of this method is that the researcher doesn’t have control over the variables; he can only report things like what has happened or what is happening.Most of the ex post facto research projects are made for descriptive studies. In these studies, the researcher seeks to measure items. Examples are; frequency of shopping, preferences of people, or similar data. Ex post facto studies also count attempts by researchers to discover causes, even when controllingvariables is out of their hands. The methods of research use for descriptive research are survey methods of every kind. It includes comparative and co-relational methods. Whereas, in analytical research, Research use facts or already available information. He critically evaluates and analyzes the material.Applied vs. FundamentalResearch can be of two types. One is applied (or action) research. Second is fundamental (to basic or pure) research. Applied research works by finding a solution for an immediate problem. These problems are faced by society or by industry whereas fundamental research is primarily concerned with the formulation of a theory. “Gathering knowledge for knowledge’s sake is termed ‘pure’ or ‘basic’ research.”Research which is more concerned with a natural phenomenon or relating to pure mathematics is fundamental research. Those research studies which are based on human behavior are also examples of fundamental research.But applied research is based at conclusions. These conclusions are facing a concrete social or business problem. Applied research is to identify social, economic or political trends. These trends may affect a particular institution or copy research or marketing research. Thus, the basic aim of applied research is to find a solution to practical problems. Fundamental research is for finding information that has a broad base of applications. It is an add-on to the already existing scientific knowledge.Quantitative vs. QualitativeQuantitative research is recognized by its name. It is the measurement of quantity or amount. It is applicable to all things which we can measure in terms of quantity. Qualitative research is simply means quality. Something related to or involving quality or kind is qualitative research. For example, when we investigate the reason behind human behavior. This type of research is to discover underlying motives and desires, using in-depth interviews for the purpose. Other techniques of such research are sentence completion tests, word association tests, story completion tests.Attitude or opinion research is also an example of kinds of qualitative research. Other examples are how people feel about a particular institution.Behavioral science has an important place for qualitative research. The aim of this research type is to discover the motives of human behavior. Through these researches, we can analyze the factors affecting behavior. This will further help in to motivate people to behave in a proper manner.Conceptual research vs. Empirical researchConceptual research is related to some abstract ideas or theory. It is mostly used by thinkers and philosophers to develop new concepts or to reinterpret existing ones. On the other hand, empirical research relies on experience or observation alone, often without due regard for system and theory. It is data-based research, coming up with conclusions which are capable of being verified by observation or experiment.We can also call it as an experimental type of research; in such research, it is necessary to get the facts first, at their source, and actively to go about doing certain things to stimulate the production of desired information. In such research, the researcher must first provide himself with a working hypothesis or guess as to the probable results. He then works to get enough facts (data) to prove or disprove his hypothesis. He then sets up experimental designs which he thinks will manipulate the persons or the materials concerned so as to bring forth the desired information.Such research is thus characterized by the experimenter’s control over the variables under study and his deliberate manipulation of one of them to study its effects. Empirical research is appropriate when the proof is sought that certainvariables affect other variables in some way. Evidence that is gathered through empirical studies or experiments, is today considered to be the most powerful support possible for a given hypothesis.When a student begins his research work, he often does not pay attention to different types of research. In my opinion, selecting a particular research type from types mentioned above of research is of vital importance. You cannot neglect your research work and get away with it.What research is not?Research work is not about asking people what they like and what notWhen you begin interviewing people involved in business decisions, you will hear them saying what they like and don’t like. “Like” word doesn’t suits a critical thinker. On subconscious level, we all wish that things we do to be liked. So it’s easy to treat likability as a leading success indicator. But the concept of “liking” is as subjective as it is empty. Getting a like is a superficial mental state unmoored from any specific behavior. This means you can’t get any useful insights from any given individual reporting that they like or hate a particular thing.Research is not a political toolDon’t let your methods com e out of a fake desire. By this, I meant to show yourself a smart or conform with other person’s picture of research. Often clients will argue for doing interviews in ausability lab even when it isn’t appropriate, just because it feels research. You’ll ne ed to explain and brief them why interviews with method and purpose are more valuable and correct than having a social conversation with a random person.In the best possibilities, you can bring up the real-world facts and insights you collect to bring an other’s perspective to internal debates and power struggles that threaten your ability to get good work done. At the very least, it’s up to everyone participating in the research to hold the line and not let interpersonal dynamics influence your findings. Watch out for those who would use information gathering for political purposes or as a popularity contest.It is not a defense of opinionsResearch is also not a defense of opinions. The aim of research work is to reveal and bring out the facts and truth on papers. You have to avoid a different situation with the opposite party’s opinions (unless you need to write a persuasive research paper).ConclusionSo I hope after reading the above information, you may get a good hand over types of research. Let’s hav e quick recall of the things we have discussed in the article. Firstly I have discussed the purpose of research for students. What importance does a research work held in a students life? After that, I have explained you the two basic types of research, i.e., applied research and pure research. Moving on further I have explained you the further types of researchwith a small comparison. In the end, I discussed what research is not.。
柳冠中 设计思考
“Professional Knowledge or Skill”. It should be a type of “Thinking Method” which is committed to the coordination of industries, businesses, trades and other aspects caused by industrial division of labor.
探求外部因素的创造方法论——“事理学”
求“是”
原理的可能和限制
达到产 品使用 目的的 组织结 构，决 定使用 目的的 实现程 度，建 立实现 目标有 机关系 。 结构的的可能和限制
实“事”
使用者的制约 使用者行为过程 和状态的制约 环境的可能和制约 决定产 品达到 使ห้องสมุดไป่ตู้目 的的条 件，明 确使用 目的的 性质。 建立温 和使用 目的相 关目标， 达到最 佳实现 程度。
"Industrial design" is based on the "Mechanism of Social Division of Labor" which is the "Superstructure" of industrial revolution and “Mass Production" economy. The birth of "BAUHAUS" was due to the establishment of "Deutsche Werkbund", which is the social and economic structure of "industrial design" - the "Soil".
中国军服的设计研究
必咖￥鞋彼黜矿膏一一
醺童鬈麓逶黧
湖爨霪霄霹骥露《篱Ｓ誊醺霄鼹。瞽１ｌ露黼ｉ
论文题目：许国聋艰础班蜀象一
学科专业：一谴丛扭Ｌ一
１乍者女生名：一——舀 彳，盐二——…——
｝旨导教师：——型妇１避——一
完成日期：
歹西上４一一
附件一：
东华大学学位论文原创性声明
本人郑重声明：我恪守学术道德，崇尚严谨学风。所早交的学位论文，是本人在导师的 指导下，独立进行研究工作所取得的成果。除文中已明确注明和引用的内容外，本论文不包 含任何其他个人或集体已经发表或撰写过的作品及成果的内容。论文为本人亲自撰写，我对 所写的内容负责，并完全意识到本声明的法律结果由本人承担。
Ｃｈｉｎｅｓｅ ａｒｍｙ ｕｎｉｆｏｒｍ ｓｙｓｔｅｍａｔｉｃａｌｌｙ，ａｎｄ ｐｒｏｐｏｓｅｓ ｉｔｓ ｄｅｓｉｇｎ
ｍｅｔｈｏｄｏｌｏｇｙ，ｗｈｉｃｈ ｗｉｌｌ ｂｅｎｅｆｉｔ ｔｈｅ ｆｕｒｔｈｅｒ ｒｅｓｅａｒｃｈ ｉｎ ｔｈｉｓ ａｒｅａ．
Ｂａｉ Ｓｈａｈ（Ｄｅｐａｒｔｍｅｎｔ ｏｆＡｒｔ Ｄｅｓｉｇｎ）
通过对现有各种期刊、书籍、资料的查阅，包括中文科技期刊数据库（全文 数据库）Ｕｐ维普咨询、中国期刊网（全文数据库），以及中国学位论文全文数据库即
８
万方数字资源等数字资源，我们发现目前所做过的研究，大多数集中在对军服材 料上的研究，以及对我国古代军用服装的研究。而对于目前我国军服样式和外观 的研究以及军服设计理论方面的专著和学术论文都相对较少。因此，中国军服的 外观设计还是一个相对来说比较空白的领域。
ｃｏｌｏｒ ｉｓｓｕｅｓ ａｎｄ ｉｍｐｅｒｆｅｃｔ ｐａｔｔｅｒｎｓ． ３． Ｂａｓｅｄ ｏｎ ｔｈｅ ａｂｏｖｅ ｒｅｓｅａｒｃｈ，ｗｅ ｐｒｏｐｏｓｅｄ ａ ｓｙｓｔｅｍａｔｉｃ
瀑布流程的五个阶段
瀑布流程的五个阶段The waterfall model consists of five key stages: requirements analysis, system design, implementation, testing, and maintenance.瀑布流程包括五个关键阶段：需求分析、系统设计、实施、测试和维护。
During the requirements analysis stage, the project team works closely with stakeholders to gather and document all functional and non-functional requirements for the system.在需求分析阶段，项目团队与利益相关者密切合作，收集和记录系统的所有功能和非功能需求。
The system design stage involves translating the requirements gathered in the previous stage into a detailed design. This includes creating system architecture, database design, and user interface design.系统设计阶段涉及将前一阶段收集的需求转化为详细设计，包括创建系统架构、数据库设计和用户界面设计。
Once the design is finalized, the implementation stage begins. This is where the actual coding and programming work takes place. Thesystem is built according to the design specifications created in the previous stage.设计确定后，实施阶段开始。
机械设计毕业论文外文翻译--机械产品方案的现代设计方法及发展趋势
Mechanical products of modern designmethodology and the programme trendsSummary: According to the current domestic and international product design, mechanical design scholars of the main features of thinking, product design methods summarized as a systematic programme, modular structure, based on product knowledge and wisdom of the four types. That the four methods of the organic link between features and its proposed product design computer programmes to achieve endeavors.Keyword:mechanical products; Programme design; TrendsIntroductionWith The rapid development of science and technology, the functional requirements of a growing number of products and complexity increase, shortened life expectancy, upgrading speed, the design of the products, particularly machinery products programme design are in urgent need .At present, computer-aided product design drawings, design calculations, processing manufacturing, production planning has been a relatively broad and in-depth study, but results and product development programme of the early computer-aided design falls far short of the design requirements. To this end, the author read a lot of literature on the basis of summarizing the design scholars and the methods used for programme design, and discussed ways of the organic link between the computer and mechanical products for programme design trends. Under the current design scholars and mechanical products used in the design of programmes of the main features of methods, the modern design of the programme approach can be summarized as the following four types:1. Systematic design methodologyThe main features of a systematic design methodology: design by several design elements as a system, the independence of each design element, the presence of various elements of the organic link between each element, and is layered, all elements of the design System design can achieve the required tasks. Systematic design concepts in the 1970s by the German scholar, Professor Paul and Baits, their theoretical system based on the general pattern set design, by design, should be rational. German Engineers in the design concepts on the basis ofcriteria developed VDI2221 "technical system design methodology and product development. Mechanical product development programmer design process model basically follows German standards VDI2221 design. In addition, many of our scholars in product design and programmer design was cited for the systematic design and other developed countries, including a representative is:(1) The user needs to be functional as a product of conception, design and structural components design, process planning, operational control of the foundation, from the macro-product development process starting, the use of qualitative methods of functional layout, systematic information to users needs rational and effective products into all stages of development objectives and technical control of the operations.(2) See product as the level of product life systems of organisms, and by systems theory to life the product design process can be divided effectively as demand levels, the achievement of the functional requirements of the specific design and product concept level. At the same time the use of life chart at abstract expression products functional requirements, and form the architecture of the products system.(3) Mechanical design system science applications into two basic issues: First, the design of products as a system to deal with, the best set of its components (modules) and their interrelationship; Second, product design process as a system, according to the design goals, and correctly, reasonably identify the various aspects of the design work and various design stages. Since each of the designers study and consider the perspective of the different focus, programmer design specific research methods are used to exist. The following are examples of some representative systematic design methods.1.1 "design analysis and guidance system"Kaleit with clear graphic description of levels of functional structures and related products abstract information systems achieved structural, functional relations graphics, modeling, and the functional connectivity between the layers. Will be designed into two complementary methods and the exchange of information, analytical methods used Nissans information can be used graphic symbols, a rich semantic model structure, can be described integration conditions, can be divided type, can be achieved in relations between the arbitrarycharacteristics, design methodology Xie and information technology integration, achieved design process information among different abstract level of relations graphics modeling. Documentation [11] network design will proceed as a design tool in the development of reactive ask semantic network design, the use of nodes and a network of lines to describe design nodes that components of the module (such as design tasks, functions, components or processing equipment), and lines to adjust the definition of nodes between different semantic relations, The design process for all the activities and results of a pre-established models for early design requirements definition to the specific description of each structure can be expressed by the relationship between the definition, computer-aided deplaning process to achieve a leap from abstract to concrete.1.2 Linkage chart lawIntegral components of the system can be divide into a functional energy, energy consumption, changing energy forms, such as various types of energy transmission, and a plan to borrow the functional components express their hope that will be based on a functional model and get a map of achieving functional structure of the automatic generation and functional structure with a map button automatic conversion, Kin seek Hop chart produced by the various design options to law.2. Structural modular design methodologyPlanning products from the perspective of: definition design tasks to the functional structure of products based products have been quoted solution (such as a spare parts components, etc.) to describe the design task of decomposition mandate to consider each sub-task existence counterpart solution of products, so that products can be in the planning stage for the elimination of the design tasks that may exist contradictions, Early projections production, costs and the development of the planned revision of the design process, thus increasing design efficiency and the reliability of the design, while also reducing the cost of new products. Feldman task to design the functions of the product mix is divided into four, (1) products → (2) functional composition→ (3) The main function of components → (4) functional components. Feature-oriented applications using structured catalogue of functional components that is more specific qualitative and quantitative description. At the same time developed a design suitablefor product development and early software tools used by early Start. Most of the functions that can be used for mechanical products have been solution, and with only a few new functions solution dedicated, specialized in the mechanical design of a functional product mix, dedicated machinery for the evaluation of the design, manufacture wind-very favorable. According to the connectivity features of mechanical parts will be consolidated into its four types:1) A direct positioning components, and since there is a readjustment of the components;2) Structure with the combination of common;3) Of a nest and the nest-style structure of the links-style components;4) A modular structure and modular components connectivity. And the use of symbols that prospective typical components and the inter-linking components rules, thus achieving connectivity between the components of the algorithms and concepts visualization.3. The characteristics of knowledge-based products in the designmethodologyDesign methods based on product characteristics knowledge of the main features: a computer language to describe the identification and design of products features experts in the field of knowledge and experience, knowledge base and establish the corresponding reasoning machine to use the storage areas have knowledge of the reasoning mechanism and the establishment of the programmer to achieve computer-assisted design products. Mechanical systems design of the programmer is based on products of the main features, and design experts in the field of knowledge and experience on the volume and decision-making, complete body type, a few integrated. Computer-aided design stage to achieve this, we must study the automatic acquisition of knowledge, expression, integration, coordination, management and use. To this end, and scholars in mechanical systems design knowledge of programmed design automated processing done a lot of research work, the methods used can be summarized in the following few.3.1 Coding methodAccording to motion transform (called functional element) the organization classified, and use codes to describe the types of institutions and function element, which has led to theestablishment of "body system programmer design expert systems" knowledge base. On this basis, binary logic of combining theory with vague integrated judge the establishment of the "expert system" reasoning mechanisms, and dedicated spaces for the four programmers designed machine tools. Use of biological evolutionary theory, through natural selection and sexual reproduction to enable organisms to the principles of evolution, in programmed design agencies, the use of network theory approach will map the structure of institutions for topography expression, and through the coding technology, the body structure and functions into individual chromosome number string of binary system, and prepared in accordance with design requirements to value use of biological evolution theory breeding control mechanism through selection, overlapping and sudden variations, and other means to eliminate low value-not to be very adaptive in the evolutionary process of the individual optimal, the best design for the agency.3.2 design catalogue methodConstruction of the "functional modules", "functional element" and "body group" - progression-style design catalogue, and this three-tiered progression of the design principles of the programmed catalogue as a mechanical transmission systems design knowledge base and the development of intelligent design aids.4. Intelligent design methodologyIntelligent design methodology is the main features: design methodology based on the theory that through 3D graphics software, intelligent design software and virtual reality technology, and multimedia, hypermedia tools for product development design, the idea expressed products, product description of the structure. In the use of mathematical systems theory, taking into a systems engineering theory, product design and system development methodologies VDI2221 technology, developed for use in the initial design of multimedia products developed software Muse.机械产品方案的现代设计方法及发展趋势摘要：根据目前国内外设计学者进行机械产品设计时的主要思维特点，将产品方案的设计方法概括为系统化、结构模块化、基于产品特征知识和智能四种类型。
设计分析 英语作文
设计分析英语作文Title: The Art of Design Analysis。
In the realm of design analysis, a multifaceted approach is paramount. It involves dissecting the intricacies of various designs, scrutinizing their components, and understanding the underlying principles that govern their functionality and aesthetics. In this essay, we will delve into the methodology of design analysis and its significance in the creative process.First and foremost, design analysis entails a comprehensive examination of the design's purpose and objectives. Whether it's a product, graphic, architectural structure, or user interface, understanding its intended use and target audience is crucial. This initial step sets the stage for a focused analysis, guiding the evaluator to discern the design's effectiveness in fulfilling its intended function.Moreover, design analysis encompasses an assessment of form and aesthetics. This involves evaluating the visual elements such as shape, color, texture, and composition employed in the design. By scrutinizing these elements, one can discern the harmony, balance, and coherence of the design, as well as its ability to evoke desired emotions or responses from the audience.Furthermore, an in-depth analysis delves into the technical aspects of the design. This includes examining the materials, construction techniques, and manufacturing processes utilized. By evaluating these technical elements, one can gauge the feasibility, durability, andsustainability of the design, as well as its potential for optimization or improvement.In addition to the tangible aspects, design analysis also involves an exploration of the conceptual and theoretical underpinnings of the design. This entails investigating the cultural, historical, and philosophical influences that inform the design's concept and execution. By contextualizing the design within broader cultural andintellectual frameworks, one can gain insights into its significance and relevance in contemporary society.Moreover, design analysis often involves comparative studies, wherein multiple designs are juxtaposed and evaluated against each other. This comparative approach allows for a nuanced understanding of the strengths, weaknesses, and unique attributes of each design, facilitating informed decision-making and iterative improvement.Furthermore, design analysis is not merely a passive observation but an active engagement with the design process. It entails critical thinking, problem-solving, and creative synthesis, as analysts seek to unravel the complexities of the design and propose innovative solutions or enhancements.In conclusion, design analysis is a multifaceted endeavor that encompasses a range of disciplines, methodologies, and perspectives. From discerning thedesign's purpose and aesthetics to evaluating its technicaland conceptual dimensions, design analysis provides valuable insights that inform the creative process and drive innovation. By adopting a systematic and rigorous approach to analysis, designers and evaluators can unlock the full potential of a design, ensuring its effectiveness, relevance, and impact in the ever-evolving landscape of design and culture.。
本科毕业设计外文文献及译文1
本科毕业设计外文文献及译文文献、资料题目：Transit Route Network Design Problem:Review文献、资料来源：网络文献、资料发表（出版）日期：2007.1院（部）：xxx专业：xxx班级：xxx姓名：xxx学号：xxx指导教师：xxx翻译日期：xxx外文文献：Transit Route Network Design Problem:Review Abstract:Efficient design of public transportation networks has attracted much interest in the transport literature and practice,with manymodels and approaches for formulating the associated transit route network design problem _TRNDP_having been developed.The presentpaper systematically presents and reviews research on the TRNDP based on the three distinctive parts of the TRNDP setup:designobjectives,operating environment parameters and solution approach.IntroductionPublic transportation is largely considered as a viable option for sustainable transportation in urban areas,offering advantages such as mobility enhancement,traffic congestion and air pollution reduction,and energy conservation while still preserving social equity considerations. Nevertheless,in the past decades,factors such as socioeconomic growth,the need for personalized mobility,the increase in private vehicle ownership and urban sprawl have led to a shift towards private vehicles and a decrease in public transportation’s share in daily commuting (Sinha2003;TRB2001;EMTA2004;ECMT2002;Pucher et al.2007).Efforts for encouraging public transportation use focuses on improving provided services such as line capacity,service frequency,coverage,reliability,comfort and service quality which are among the most important parameters for an efficient public transportation system(Sinha2003;Vuchic2004.) In this context,planning and designing a cost and service efficientpublic transportation network is necessary for improving its competitiveness and market share. The problem that formally describes the design of such a public transportation network is referred to as the transit route network design problem(TRNDP);it focuses on the optimization of a number of objectives representing the efficiency of public transportation networks under operational and resource constraints such as the number and length of public transportation routes, allowable service frequencies,and number of available buses(Chakroborty2003;Fan and Machemehl2006a,b).The practical importance of designing public transportation networks has attractedconsiderable interest in the research community which has developed a variety of approaches and modelsfor the TRNDP including different levels of design detail and complexity as well as interesting algorithmic innovations.In thispaper we offer a structured review of approaches for the TRNDP;researchers will obtain a basis for evaluating existing research and identifying future research paths for further improving TRNDP models.Moreover,practitioners will acquire a detailed presentation of both the process and potential tools for automating the design of public transportation networks,their characteristics,capabilities,and strengths.Design of Public Transportation NetworksNetwork design is an important part of the public transportation operational planning process_Ceder2001_.It includes the design of route layouts and the determination of associated operational characteristics such as frequencies,rolling stock types,and so on As noted by Ceder and Wilson_1986_,network design elements are part of the overall operational planning process for public transportation networks;the process includes five steps:_1_design of routes;_2_ setting frequencies;_3_developing timetables;_4_scheduling buses;and_5_scheduling drivers. Route layout design is guided by passenger flows:routes are established to provide direct or indirect connection between locations and areas that generate and attract demand for transit travel, such as residential and activity related centers_Levinson1992_.For example,passenger flows between a central business district_CBD_and suburbs dictate the design of radial routes while demand for trips between different neighborhoods may lead to the selection of a circular route connecting them.Anticipated service coverage,transfers,desirable route shapes,and available resources usually determine the structure of the route network.Route shapes areusually constrained by their length and directness_route directness implies that route shapes are as straight as possible between connected points_,the usage of given roads,and the overlapping with other transit routes.The desirable outcome is a set of routesconnecting locations within a service area,conforming to given design criteria.For each route, frequencies and bus types are the operational characteristics typically determined through design. Calculations are based on expected passenger volumes along routes that are estimated empirically or by applying transit assignmenttechniques,under frequency requirement constraints_minimum and maximum allowedfrequencies guaranteeing safety and tolerable waiting times,respectively_,desired load factors, fleet size,and availability.These steps as well as the overall design.process have been largely based upon practical guidelines,the expert judgment of transit planners,and operators experience_Baaj and Mahmassani1991_.Two handbooks by Black _1995_and Vuchic_2004_outline frameworks to be followed by planners when designing a public transportation network that include:_1_establishing the objectives for the network;_2_ defining the operational environment of the network_road structure,demand patterns,and characteristics_;_3_developing;and_4_evaluating alternative public transportation networks.Despite the extensive use of practical guidelines and experience for designing transit networks,researchers have argued that empirical rules may not be sufficient for designing an efficient transit network and improvements may lead to better quality and more efficient services. For example,Fan and Machemehl_2004_noted that researchers and practitioners have been realizing that systematic and integrated approaches are essential for designing economically and operationally efficient transit networks.A systematic design process implies clear and consistent steps and associated techniques for designing a public transportation network,which is the scope of the TRNDP.TRNDP:OverviewResearch has extensively examined the TRNDP since the late1960s.In1979,Newell discussed previous research on the optimal design of bus routes and Hasselström_1981_ analyzed relevant studies and identified the major features of the TRNDP as demand characteristics,objective functions,constraints,passengerbehavior,solution techniques,and computational time for solving the problem.An extensive review of existing work on transit network design was provided by Chua_1984_who reported five types of transit system planning:_1_manual;_2_marketanalysis;_3_systems analysis;_4_systems analysis with interactive graphics;and_5_ mathematical optimization approach.Axhausemm and Smith_1984_analyzed existing heuristic algorithms for formulating the TRNDP in Europe,tested them,anddiscussed their potential implementation in the United States.Ceder and Wilson_1986_reportedprior work on the TRNDP and distinguished studies into those that deal with idealized networks and to those that focus on actual routes,suggesting that the main features of the TRNDP include demand characteristics,objectivesand constraints,and solution methods.At the same period,Van Nes et al._1988_grouped TRNDP models into six categories:_1_ analytical models for relating parameters of the public transportation system;_2_models determining the links to be used for public transportation route construction;_3_models determining routes only;_4_models assigning frequencies to a set of routes;_5_two-stage models for constructing routes and then assigning frequencies;and_6_models for simultaneously determining routes and frequencies.Spacovic et al._1994_and Spacovic and Schonfeld_1994_proposed a matrix organization and classified each study according to design parameters examined,objectives anticipated,network geometry,and demand characteristics. Ceder and Israeli_1997_suggested broad categorizations for TRNDP models into passenger flow simulation and mathematical programming models.Russo_1998_adopted the same categorization and noted that mathematical programming models guarantee optimal transit network design but sacrifice the level of detail in passenger representation and design parameters, while simulation models address passenger behavior but use heuristic procedures obtaining a TRNDP solution.Ceder_2001_enhanced his earlier categorization by classifying TRNDP models into simulation,ideal network,and mathematical programming models.Finally,in a recent series of studies,Fan and Machemehl_2004,2006a,b_divided TRNDP approaches into practical approaches,analytical optimization models for idealized conditions,and metaheuristic procedures for practical problems.The TRNDP is an optimization problem where objectives are defined,its constraints are determined,and a methodology is selected and validated for obtaining an optimal solution.The TRNDP is described by the objectives of the public transportation network service to be achieved, the operational characteristics and environment under which the network will operate,and the methodological approach for obtaining the optimal network design.Based on this description of the TRNDP,we propose a three-layer structure for organizing TRNDP approaches_Objectives, Parameters,and Methodology_.Each layer includes one or more items that characterize each study.The“Objectives”layer incorporates the goals set when designing a public transportation system such as the minimization of the costs of the system or the maximization of the quality of services provided.The“Parameters”layer describes the operating environment and includes both the design variables expected to be derived for the transit network_route layouts,frequencies_as well as environmental and operational parameters affecting and constraining that network_for example,allowable frequencies,desired load factors,fleet availability,demand characteristics and patterns,and so on_.Finally,the“Methodology”layer covers the logical–mathematical framework and algorithmic tools necessary to formulate and solve the TRNDP.The proposed structure follows the basic concepts toward setting up a TRNDP:deciding upon the objectives, selecting the transit network items and characteristics to be designed,setting the necessary constraints for the operating environment,and formulating and solving the problem. TRNDP:ObjectivesPublic transportation serves a very important social role while attempting to do this at the lowest possible operating cost.Objectives for designing daily operations of a public transportation system should encompass both angles.The literature suggests that most studies actually focus on both the service and economic efficiency when designing such a system. Practical goals for the TRNDP can be briefly summarized as follows_Fielding1987;van Oudheudsen et al.1987;Black1995_:_1_user benefit maximization;_2_operator cost minimization;_3_total welfare maximization;_4_capacity maximization;_5_energy conservation—protection of the environment;and_6_individual parameter optimization.Mandl_1980_indicated that public transportation systems have different objectives to meet. He commented,“even a single objective problem is difficult to attack”_p.401_.Often,these objectives are controversial since cutbacks in operating costs may require reductions in the quality of services.Van Nes and Bovy_2000_pointed out that selected objectives influence the attractiveness and performance of a public transportation network.According to Ceder and Wilson_1986_,minimization of generalized cost or time or maximization of consumer surplus were the most common objectives selected when developing transit network design models. Berechman_1993_agreed that maximization of total welfare is the most suitable objective for designing a public transportation system while Van Nes and Bovy_2000_argued that the minimization of total user and system costs seem the most suit able and less complicatedobjective_compared to total welfare_,while profit maximization leads to nonattractive public transportation networks.As can be seen in Table1,most studies seek to optimize total welfare,which incorporates benefits to the user and to the er benefits may include travel,access and waiting cost minimization,minimization of transfers,and maximization of coverage,while benefits for the system are maximum utilization and quality of service,minimization of operating costs, maximization of profits,and minimization of the fleet size used.Most commonly,total welfare is represented by the minimization of user and system costs.Some studies address specific objectives from the user,theoperator,or the environmental perspective.Passenger convenience,the number of transfers, profit and capacity maximization,travel time minimization,and fuel consumption minimization are such objectives.These studies either attempt to simplify the complex objective functions needed to setup the TRNDP_Newell1979;Baaj and Mahmassani1991;Chakroborty and Dwivedi2002_,or investigate specific aspects of the problem,such as objectives_Delle Site and Fillipi2001_,and the solution methodology_Zhao and Zeng2006;Yu and Yang2006_.Total welfare is,in a sense,a compromise between objectives.Moreover,as reported by some researchers such as Baaj and Mahmassani_1991_,Bielli et al._2002_,Chackroborty and Dwivedi_2002_,and Chakroborty_2003_,transit network design is inherently a multiobjective problem.Multiobjective models for solving the TRNDP have been based on the calculation of indicators representing different objectives for the problem at hand,both from the user and operator perspectives,such as travel and waiting times_user_,and capacity and operating costs _operator_.In their multiobjective model for the TRNDP,Baaj and Majmassani_1991_relied on the planner’s judgment and experience for selecting the optimal public transportation network,based on a set of indicators.In contrast,Bielli et al._2002_and Chakroborty and Dwivedi_2002_,combined indicators into an overall,weighted sum value, which served as the criterion for determining the optimaltransit network.TRNDP:ParametersThere are multiple characteristics and design attributes to consider for a realistic representation of a public transportation network.These form the parameters for the TRNDP.Part of these parameters is the problem set of decision variables that define its layout and operational characteristics_frequencies,vehicle size,etc._.Another set of design parameters represent the operating environment_network structure,demand characters,and patterns_, operational strategies and rules,and available resources for the public transportation network. These form the constraints needed to formulate the TRNDP and are,a-priori fixed,decided upon or assumed.Decision VariablesMost common decision variables for the TRNDP are the routes and frequencies of the public transportation network_Table1_.Simplified early studies derived optimal route spacing between predetermined parallel or radial routes,along with optimal frequencies per route_Holroyd1967; Byrne and Vuchic1972;Byrne1975,1976;Kocur and Hendrickson1982;Vaughan1986_,while later models dealt with the development of optimal route layouts and frequency determination. Other studies,additionally,considered fares_Kocur and Hendrickson1982;Morlok and Viton 1984;Chang and Schonfeld1991;Chien and Spacovic2001_,zones_Tsao and Schonfeld1983; Chang and Schonfeld1993a_,stop locations_Black1979;Spacovic and Schonfeld1994; Spacovic et al.1994;Van Nes2003;Yu and Yang2006_and bus types_Delle Site and Filippi 2001_.Network StructureSome early studies focused on the design of systems in simplified radial_Byrne1975;Black 1979;Vaughan1986_,or rectangular grid road networks_Hurdle1973;Byrne and Vuchic1972; Tsao and Schonfeld1984_.However,most approaches since the1980s were either applied to realistic,irregular grid networks or the network structure was of no importance for the proposed model and therefore not specified at all.Demand PatternsDemand patterns describe the nature of the flows of passengers expected to be accommodated by the public transportation network and therefore dictate its structure.For example,transit trips from a number of origins_for example,stops in a neighborhood_to a single destination_such as a bus terminal in the CBD of a city_and vice-versa,are characterized as many-to-one_or one-tomany_transit demand patterns.These patterns are typically encountered in public transportation systems connecting CBDs with suburbs and imply a structure of radial orparallel routes ending at a single point;models for patterns of that type have been proposed by Byrne and Vuchic_1972_,Salzborn_1972_,Byrne_1975,1976_,Kocur and Hendrickson _1982_,Morlok and Viton_1984_,Chang and Schonfeld_1991,1993a_,Spacovic and Schonfeld_1994_,Spacovic et al._1994_,Van Nes_2003_,and Chien et al._2003_.On the other hand,many-to-many demand patterns correspond to flows between multiple origins and destinations within an urban area,suggesting that the public transportation network is expected to connect various points in an area.Demand CharacteristicsDemand can be characterized either as“fixed”_or“inelastic”_or“elastic”;the later meaning that demand is affected by the performance and services provided by the public transportation network.Lee and Vuchic_2005_distinguished between two types of elastic demand:_1_demand per mode affected by transportation services,with total demand for travel kept constant;and_2_total demand for travel varying as a result of the performance of the transportation system and its modes.Fan and Machemehl_2006b_noted that the complexity of the TRNDP has led researchers intoassuming fixed demand,despite its inherent elastic nature.However,since the early1980s, studies included aspects of elastic demand in modeling the TRNDP_Hasselstrom1981;Kocur and Hendrickson1982_.Van Nes et al._1988_applied a simultaneous distribution-modal split model based on transit deterrence for estimatingdemand for public transportation.In a series of studies,Chang and Schonfeld_1991,1993a,b_ and Spacovic et al._1994_estimated demand as a direct function of travel times and fares with respect to their elasticities,while Chien and Spacovic2001_,followed the same approach assuming that demand is additionally affected by headways,route spacing and fares.Finally, studies by Leblanc_1988_,Imam_1998_,Cipriani et al._2005_,Lee and Vuchic_2005_;and Fan and Machemehl_2006a_based demand estimation on mode choice models for estimating transit demand as a function of total demand for travel.中文译文：公交路线网络设计问题：回顾摘要：公共交通网络的有效设计让交通理论与实践成为众人关注的焦点，随之发展出了很多规划相关公交路线网络设计问题（TRNDP）的模型与方法。
实证研究 英文
实证研究英文Empirical research refers to a type of research that is based on observation and experience rather than theory or speculation. It is a systematic and structured approach to study a particular phenomenon or problem using data collected through direct observation, experimentation, or surveys. The aim of empirical research is to test and validate theories by examining the relationship between variables and providing evidence to support or reject hypotheses.One of the major characteristics of empirical research is the reliance on data, which can be obtained through various methods. Observation is one common method used in empirical research, where researchers directly observe and record data about the phenomenon they are studying. For example, a researcher may observe and take notes on the behavior of individuals in a certain social setting.Experimentation is another method used in empirical research, where researchers manipulate variables and measure their effects on the outcome of interest. This method allows for causal inferences to be made, as researchers can control and manipulate the variables being studied. For example, in a drug trial, researchers may randomly assign participants to different groups and measure the effects of the drug on their symptoms.Surveys and questionnaires are also commonly used in empirical research to collect data. Researchers can design surveys to measure attitudes, beliefs, or behaviors of individuals. This method allows for large-scale data collection and can provide valuable insightsinto the opinions and behaviors of a specific population. For example, a researcher may distribute a survey to measure public opinion on a political issue.Once data is collected, it is then analyzed using statistical methods. This involves organizing, summarizing, and interpreting the data to draw conclusions. Statistical analysis allows researchers to examine the relationships between variables and determine if there is a significant association or difference.The results of empirical research are typically presented in a research paper or report. These papers follow a specific structure, including an introduction, literature review, methodology, results, and conclusion. The introduction provides context and background information on the research topic, the literature review examines previous studies, the methodology explains how the research was conducted, the results present the findings, and the conclusion summarizes and interprets the results.In conclusion, empirical research is a systematic and structured approach to study a phenomenon or problem using direct observation, experimentation, or surveys. It relies on data collection and analysis to test and validate theories. The results of empirical research can provide valuable insights and evidence to support or reject hypotheses.。
水下机器人毕业设计英语
水下机器人毕业设计英语Underwater Robotics: A Comprehensive Guide for Senior Design Projects.Introduction.Underwater robotics, a captivating andinterdisciplinary field, presents a wealth of opportunities for senior design projects. With its diverse applications in ocean exploration, marine science, and industry, it offers students an unparalleled platform to showcase their creativity and technical prowess. This comprehensive guide will provide an in-depth exploration of the key aspects of underwater robotics, equipping students with the knowledge and understanding necessary to embark on successful senior design projects in this exciting field.Applications of Underwater Robotics.Underwater robotics encompasses a vast range ofapplications, each posing unique design challenges and requiring specialized knowledge. These applications include:Ocean Exploration: Exploring the depths of the ocean, mapping underwater landscapes, and studying marine ecosystems.Marine Science: Conducting scientific research, monitoring environmental changes, and studying marine life.Industry: Inspecting underwater structures, performing maintenance tasks, and exploiting subsea resources.Military: Deploying underwater vehicles for surveillance, reconnaissance, and combat operations.Key Considerations for Senior Design Projects.When embarking on an underwater robotics senior design project, it is crucial to consider several key factors:Vehicle Design: Determine the type of vehicle (ROV,AUV, or hybrid), its size, shape, and propulsion system.Control Systems: Design and implement control algorithms for navigation, positioning, and manipulation.Sensing and Perception: Integrate sensors for obstacle avoidance, object detection, and environmental monitoring.Communication and Data Transmission: Establishreliable underwater communication channels and develop protocols for data transmission.Materials and Fabrication: Select appropriate materials and fabrication methods to ensure the vehicle's durability and performance in the underwater environment.Design Process and Methodology.The design process for an underwater robotics project typically involves the following steps:Problem Definition: Define the project objectives andidentify the design constraints.Concept Generation: Explore various design concepts and evaluate their feasibility.Detailed Design: Develop detailed plans and specifications for the vehicle's components and systems.Fabrication and Assembly: Physically construct the vehicle and integrate all its components.Testing and Evaluation: Conduct thorough testing to verify the vehicle's functionality and performance.Common Challenges and Troubleshooting.Underwater robotics projects often encounter various challenges, including:Harsh Environment: Dealing with extreme pressure, temperature, and salinity levels.Limited Visibility: Operating in low or zerovisibility conditions.Communication Difficulties: Establishing reliable underwater communication links.Mechanical Failures: Ensuring the robustness and reliability of vehicle components.Power Management: Optimizing energy consumption and managing battery life.Troubleshooting these challenges requires a systematic approach, involving thorough analysis, testing, and iterative design modifications.Conclusion.Underwater robotics presents an exciting and rewarding field for senior design projects. By understanding the key applications, design considerations, design process, and common challenges, students are well-equipped to embark oninnovative and successful projects. With its potential to advance scientific discovery, industry practices, and societal progress, underwater robotics promises to continue captivating the minds of future engineers and researchers.。
常用的培训方法论
常用的培训方法论English:One of the commonly used training methodologies is the ADDIE model, which stands for Analysis, Design, Development, Implementation, and Evaluation. This model is a systematic approach to instructional design and is widely used in the training industry. Another popular methodology is the Kirkpatrick Model, which focuses on evaluating the effectiveness of training programs by assessing four levels: reaction, learning, behavior, and results. The Action Learning approach is also widely used, which involves collaborative problem-solving and learning from real-life experiences. Additionally, the Experiential Learning model, popularized by David Kolb, emphasizes the importance of experiential learning through concrete experiences, reflective observation, abstract conceptualization, and active experimentation. These are just a few examples of the many training methodologies available for organizations to choose from, each with its own strengths and benefits.Translated content:常用的培训方法论之一是ADDIE模型，它代表分析、设计、开发、实施和评估。
动机和方法的重要性英语作文四级
动机和方法的重要性英语作文四级英文回答：Motivation and methodology are fundamental aspects of any research endeavor. Motivation, the driving force behind a study, determines its purpose and significance. It provides the researcher with the impetus to pursue a particular line of inquiry and shapes the research questions and hypotheses. Without motivation, research lacks direction and purpose.Methodology, on the other hand, refers to the systematic and structured approach used to conduct a research study. It encompasses the research design, data collection techniques, and data analysis procedures. A sound methodology ensures that the research findings are credible, reliable, and generalizable. It also allows other researchers to replicate the study or build upon its results.The significance of motivation cannot be overstated. It is the catalyst that ignites the research process and sustains it throughout. Researchers who are deeply motivated to answer important questions or address real-world problems are more likely to produce groundbreaking and meaningful research. Motivation fosters creativity, perseverance, and a commitment to excellence.Equally important is the role of methodology. A well-designed methodology provides a roadmap for the research process, ensuring that it is conducted systematically and rigorously. It enables researchers to collect and analyze data objectively, minimizing bias and ensuring the validity of the findings. A flawed methodology, on the other hand, can lead to unreliable or even misleading results.中文回答：动机和方法的重要性。
方法论建设的能力描述
方法论建设的能力描述Methodology is a cornerstone of any research project, providing a roadmap for how data will be collected, analyzed, and interpreted. Developing a strong methodology requires a combination of theoretical understanding, practical skills, and critical thinking. Researchers must carefully consider the research question, the appropriate methods for data collection, and the potential biasesthat may affect the results. Without a well-developed methodology,a research project risks producing unreliable or invalid results.方法论是任何研究项目的基石，为如何收集、分析和解释数据提供了一份路线图。
发展一个强大的方法论需要理论理解、实践技能和批判性思维的结合。
研究人员必须仔细考虑研究问题、数据收集的适当方法和可能影响结果的偏见。
没有一个完善的方法论，一个研究项目就有可能产生不可靠或无效的结果。
One important aspect of methodology development is the choice of research design. Researchers must decide whether to use a qualitative, quantitative, or mixed-methods approach based on the nature of their research question. Each approach has its ownstrengths and weaknesses, and researchers must carefully consider which design best fits their research goals. Additionally, researchers must consider the practical constraints of their research, such as time, resources, and access to participants.方法论发展的一个重要方面是研究设计的选择。
机器人冲压自动线的生产节拍优化
欢迎订阅欢迎撰稿欢迎发布产品广告信息E I C Vo l .15 2008 No.6 75 神经网络可以任意精度逼近任何连续函数。
从结构外表看,P I D 神经网络的隐含层神经元的个数过少,但实际上,其中的积分元等价k 个一般神经元,这些一般神经元的输入分别为1,2,…,k -1,k 时刻的输入层神经元输出值的总和值,如图2所示。
由式(1)到式(8)可知,P I D 神经网络中的比例元、积分元和微分元的稳态输入输出特性都属于广义sigm oid 函数,因此它也具有任意连续函数逼近能力。
4 P I D 神经网络进行变桨控制系统的辨识4.1 风机模型以直驱电机为辨识系统,由于风力机与发电机采用直接驱动方式连接,这是一个典型的非线性模型,但这个模型能够反映变速风力发电机组的基本动态特性:J r dωr d t=T a -T e(9)式中:J r ———为风轮的转动惯量;ωr ———为风轮转动的角速度;T a ———为风轮的气动转距;T e ———为发电机获得的转距。
其中,气动力转距T a 由下式表示:T a =12ρC T (λ,β)RS v2(10)风机的转距T e 由下式表示:T e =12ρC P (λ,β)SR 3ω2(11)由式(9)、(10)和(11)得:J r d ωr d t =12ρC T (λ,β)R 3S ω2-12ρC P (λ,β)SR 3ω2(12)令k 1=12ρC T (λ,β)R 3S 1J r ,k 2=12ρC P (λ,β)SR 31J r可得:d ωr d t=(k 1-k 2)ω2离散化后为:ωr (k )-ωr (k -1)=(k 1-k 2)ω2(k )4.2 系统辨识辨识结构图如图3所示,网络采用批学习方法,每隔200个采样点学习一次,目标函数为:E =1200∑200k =1e 2(k )=1200∑200k =1[y (k )-y ′(k )]2图3辨识系统的结构图 图4系统辨识的衰减曲线其中,y (k )为对象的输出,y ′(k )为P I D 神经网络的输出。
调研报告的英文缩写
调研报告的英文缩写A research report is commonly abbreviated as RR. It is a document that presents the findings, analysis, and conclusions from a research study or investigation. The purpose of a research report is to provide a comprehensive and systematic overview of the research project, including the methodologies used, data collected, and results obtained. Research reports are an essential part of academic and scientific research, as they allow researchers to communicate their findings to the wider scientific community and contribute to the existing body of knowledge.The structure of a research report typically includes an abstract, introduction, literature review, methodology, results, discussion, and conclusion. The abstract provides a brief summary of the report, highlighting the research objectives, methodologies, and main findings. The introduction provides background information on the topic of study, establishes the research gap or problem, and outlines the research objectives. The literature review summarizes previous studies and research that are relevant to the topic and provides a theoretical framework for the current study. The methodology section describes the research design, data collection methods, and analysis techniques used. The results section presents the findings of the study, often in the form of tables, charts, and graphs. The discussion section interprets the results, compares them with previous research, and explores their implications. Finally, the conclusion summarizes the main findings, discusses their significance and limitations, and suggests future directions for research.Research reports are typically written in a clear and concisemanner, using a formal and objective tone. They should be well-organized, with headings and subheadings to guide the reader through the report. In addition to the main text, research reports may also include appendices to provide additional details, such as questionnaires, interview transcripts, or statistical analyses. It is important for researchers to adhere to specific formatting and citation styles, such as APA (American Psychological Association) or MLA (Modern Language Association), to maintain consistency and ensure the report's credibility.In conclusion, a research report is an important tool for communication in the field of research. It allows researchers to share their findings, contribute to the existing knowledge, and advance their specific field of study. Through a systematic and comprehensive structure, research reports provide a detailed overview of the research project, including its objectives, methodologies, results, and conclusions. By writing and disseminating research reports, researchers can contribute to the growth and development of their academic or scientific community.。
工程方案设计英语
工程方案设计英语IntroductionThe proposed project aims to design and implement a new and improved wastewater treatment system for a municipal wastewater treatment plant. The current system is outdated and insufficient to handle the growing population and industrial activities in the area. The new system will use advanced technologies and innovative processes to effectively treat the wastewater and meet the required effluent standards. This project proposal will outline the scope, objectives, and methodology of the proposed wastewater treatment system.ScopeThe scope of the project includes the design, construction, and commissioning of a new wastewater treatment system for the municipal wastewater treatment plant. The proposed system will have a treatment capacity of 10 million gallons per day (MGD) and will be designed to treat both domestic and industrial wastewater. The system will be designed to meet the effluent standards set by the regulatory authorities and will include advanced treatment processes such as membrane bioreactors, ultraviolet disinfection, and nutrient removal.ObjectivesThe main objectives of the project are as follows:1. Design a new and improved wastewater treatment system that can effectively treat both domestic and industrial wastewater.2. Increase the treatment capacity of the plant to 10 MGD to accommodate the growing population and industrial activities in the area.3. Meet the effluent standards set by the regulatory authorities for parameters such as biochemical oxygen demand (BOD), total suspended solids (TSS), and nutrient removal.4. Implement advanced treatment processes and technologies to enhance the efficiency and effectiveness of the wastewater treatment system.MethodologyThe proposed project will follow the following methodology:1. Site Assessment: A detailed assessment of the existing wastewater treatment plant and the surrounding area will be conducted to understand the current system's limitations and identify the requirements for the new system.2. Process Design: The process design will involve the selection of appropriate treatment processes and technologies based on the site assessment and effluent standards. The designwill include the layout, sizing, and configuration of the treatment units such as screens, grit chambers, primary clarifiers, biological reactors, and disinfection units.3. Technology Selection: The selection of advanced treatment technologies such as membrane bioreactors, ultraviolet disinfection, and nutrient removal will be based on the treatment requirements and the site-specific conditions.4. Construction and Commissioning: The construction phase will involve the installation of the new treatment units, piping, and electrical systems. Once the construction is completed, the system will be commissioned to ensure that it is functioning as per the design specifications.5. Operations and Maintenance: Training will be provided to the plant operators and maintenance personnel to operate and maintain the new system effectively. A proactive maintenance schedule will be developed to ensure the efficient and smooth operation of the wastewater treatment system.Project DeliverablesThe project deliverables will include the following:1. Detailed design drawings and specifications for the new wastewater treatment system.2. Commissioned and fully operational wastewater treatment plant with a treatment capacity of 10 MGD.3. Operations and maintenance manual for the plant operators and maintenance personnel.4. Training documentation and sessions for the plant staff on the new treatment system. Project ScheduleThe proposed project is estimated to be completed within 18 months. The schedule will include the following key milestones:1. Site Assessment: 2 months2. Process Design: 3 months3. Technology Selection: 1 month4. Construction and Commissioning: 10 months5. Operations and Maintenance: 2 monthsBudgetThe estimated budget for the proposed project is $15 million. The budget will cover the costs of design, construction, equipment, materials, labor, and contingency. A detailed costbreakdown will be provided in the project's financial plan, including a capital budget, operating expenses, and projected savings from the improved efficiency of the new system. ConclusionThe proposed project aims to design and implement a new and improved wastewater treatment system for a municipal wastewater treatment plant. The new system will have a treatment capacity of 10 MGD and will be designed to effectively treat both domestic and industrial wastewater while meeting the required effluent standards. The project will follow a systematic methodology, including site assessment, process design, technology selection, construction, commissioning, and operations and maintenance. The project deliverables will include detailed design drawings, a commissioned and operational wastewater treatment plant, operations and maintenance manuals, and training documentation. The estimated budget for the project is $15 million, and the project is expected to be completed within 18 months. The proposed wastewater treatment system will help the municipality address the increasing demand for wastewater treatment and comply with the regulatory effluent standards.。
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Systematic design methodology and construction of UAV helicopters qGuowei Cai,Lin Feng,Ben M.Chen *,Tong H.LeeDepartment of Electrical and Computer Engineering,National University of Singapore,Singapore 117576,Singaporea r t i c l e i n f o Article history:Received 28November 2007Accepted 29May 2008Keywords:UAV helicoptersVirtual design environment Anti-vibrationHardware constructiona b s t r a c tIn this paper,we present a comprehensive design methodology for constructing small-scale UAV helicop-ters.The systematic design procedure,which includes hardware component selection,design and inte-gration,as well as experimental evaluation,is utilized to construct a fully functional UAV helicopter,named SheLion.Various ground and flight tests have been performed to verify the feasibility and reliabil-ity of SheLion.This simple,systematic and effective methodology can be easily followed and used for building small-scale UAV helicopters for general research purposes.Ó2008Elsevier Ltd.All rights reserved.1.IntroductionUnmanned aerial vehicles (UAVs)have become a hot research topic in the last decade worldwide.Their great potential has been explored in numerous military and civil implementations.Among various UAVs,small-scale UAV helicopter is especially attractive to the academic circle due to its small size,unique flight capacities,outstanding maneuverability and low cost.Many research groups have constructed their own UAV helicopters for their research pur-poses (see,for example [4,6,13–15,17]).Success has been achieved in many research areas such as software design and integration (see,for example [5,22]),modeling identification (see,for example,[10,13,19,21]),control techniques implementation (see,for exam-ple [9,20]),aerial image processing (see,for example [3,11,12,17,18]),to name a few.Designing a small-scale UAV helicopter is a challenging job,especially to the researchers with insufficient background knowl-edge on aerodynamics and mechanics of rotorcraft.Problems may come from various aspects such as hardware components selection,software design and anti-vibration solution.Further-more,the commonly adopted radio-controlled (RC)hobby helicop-ter has strictly limited payload (less than 6kg),which imposes much more difficulty on the design process.Although some small-scale UAV platforms have been successfully built up and implemented,there is no uniform,time-saving and effective design methodology that has been clearly documented in the literature.Our UAV research team has recently constructed two small-scale UAV helicopters for our research purposes in implementing advanced nonlinear flight control law and tracking ground targets.The first UAV helicopter,called HeLion [1],has been successfully implemented to verify the superiority of proposed nonlinear con-trol method,that is,the composite nonlinear feedback (CNF)con-trol,in near hover [2]and full envelope flight [16].Although the design and debugging procedure was pretty lengthy (one whole year)with two researchers involved,we have accumulated rich experiences and managed to summarize a simple,systematic and effective design methodology of constructing small-scale UAV heli-copter with minimum complexity and time cost.Such methodol-ogy includes four steps:(1)virtual design environment selection;(2)hardware component selection;(3)comprehensive design and integration;and (4)ground and flight test evaluation.Based on this procedure,we construct our second UAV helicopter,pared to its counterpart,HeLion,SheLion is lighter in weight with more compact and systematic hardware layout design and more functions such as onboard image processing.Further-more,the whole constructing period including design,assembling,debugging and testing is greatly shorten to three months with the same manpower involved.The outline of this paper is as follows:Following the logical or-der of the construction of SheLion,in Section 2,we first introduce the virtual design environment,SolidWorks,which is used for building up the virtual layout of SheLion.In Section 3,the hard-ware components and the reasons for their selection are presented.In Section 4,the comprehensive design procedure including on-board layout design,anti-vibration design and power supply de-sign is described.The ground and flight test results are given in Section 5to evaluate the working performance and reliability of SheLion.Finally,in Section 6,we draw our concluding remarks.0957-4158/$-see front matter Ó2008Elsevier Ltd.All rights reserved.doi:10.1016/j.mechatronics.2008.05.011qThis work is supported by the Defence Science and Technology Agency (DSTA)of Singapore under the 2003Temasek Young Investigator Award.*Corresponding author.Tel.:+6565162289;fax:+6567791103.E-mail addresses:caiguowei@.sg (G.Cai),g0500067@.sg (L.Feng),bmchen@.sg (B.M.Chen),eleleeth@.sg (T.H.Lee).Mechatronics 18(2008)545–558Contents lists available at ScienceDirectMechatronicsj o ur na l h om e pa ge :w w w.e ls e v ie r.c o m/lo c at e/me c h at r on ics2.Virtual design environmentThefirst step for constructing the UAV helicopter,SheLion,is to choose a suitable virtual design environment.The design proce-dure in the construction of HeLion was mainly based on two-dimensional computer-aided-design(2D CAD)blueprints.The lack of a powerful3D design environment caused great difficulty in lay-out design and the integration of hardware components.As a result the design and integration procedure was iterated for quite a num-ber of times,which had prolonged the total constructing time for months.To avoid such a problem,in constructing SheLion,we em-ploy a powerful virtual design environment,SolidWorks,which has the following main advantages:1.Easy to use:Users can be familiar with the necessary functionsin a short time through learning several key examples.2.Powerful3D and2D design:In SolidWorks,the virtual counter-part can be modeled to be identical with the real hardware component,both in shape and color.When the3D design isfin-ished,the corresponding2D views will be generated at the same time for the convenience of mechanical manufacturing.3.Physical description:Each virtual component can be parameter-ized with necessary physical parameters such as density and weight.The center of gravity(CG)can be either calculated by SolidWorks or arbitrarily specified.Such a function is especially useful in the layout design of the onboard computer system of the UAV.4.Animation function:For certain components,which can move orrotate,we can emulate their motions by using an animation function.This function is essential when some complicated devices,such as a two-degree-of-freedom camera frame,are needed to be mounted onboard.Such a software-facilitated design concept is one of the most remarkable features of our proposed UAV design methodology and is closely followed throughout in the design procedure given in this work.The outline of this paper is as follows:In Section3, we present the hardware selection of the UAV helicopter systems and the construction of their virtual counterparts.Each virtual counterpart is characterized with(1)the location and dimension of its mounting hole;(2)the center of gravity;(3)the dimension of the object;and(4)its weight,which are to be specified for fur-ther development such as layout design and integration.In Section 4,each of the design steps is to be tuned virtually till it is fully determined.The virtually constructed UAV and its real counterpart are displayed in Fig.1.It is noted that the SheLion is carefully built up in the virtual design environment,which provides an excellent backup of our design process.Through using such a software-facil-itated design procedure,we have successfully avoided unnecessary iterations and greatly shortened the design period.3.Hardware components selection for SheLion UAV helicopterOur SheLion UAV helicopter system,whose working principle is shown in Fig.2,is composed of the following four parts:(1)a radio-controlled(RC)bare helicopter;(2)an onboard computer system;(3)a manual control system;and(4)a ground supporting system. Among them,the RC helicopter is the baseline to be upgraded. The onboard computer system is the most important part,in charge of collecting necessary in-flight data,such as helicopter states,main rotor’s RPM(rotations per minute),sonar-measured altitude and servo actuator deflection,and onboard images,analyzing the data and images collected,and implementingflight control laws as well as logging data to the compactflash(CF)memory cards.Each of the solid block in Fig.2represents a specific hardware component and their functions and selections are to be presented in detail in Sec-tions3.1–3.6and3.7.The manual control system,which is normally a radio-controlled joystick,always comes with the RC helicopter and is used to control the helicopter by the pilot in manualflight stly,the ground supporting system is used to monitor the flight status of the UAV helicopter online and to communicate with the onboard computer system.From Fig.2it can be noted that building a UAV helicopter is heavily related to hardware compo-nents selected.In what follows,we present the selection of neces-sary hardware components for SheLion.3.1.RC helicopterA high quality RC bare helicopter,Raptor90,is selected as the basic rotorcraft of SheLion.It is shown in Fig.3along with its vir-tual counterpart.Some key physical parameters of the helicopter are listed in Table1.Five onboard servo actuators are used to drive the helicopter.More specifically,the aileron,elevator and collec-tive pitch servos are in charge of tilting the swash plate to realize the rolling motion,pitching motion and to change the main rotor’s collective pitch angle.The throttle servo,cooperated with a hobby-purpose RPM governor,is used to control the engine power.One high-speed digital servo,associated by a low cost yaw rate gyro, is employed to control the yaw motion.The commonly used stabi-lizer bar,which acts as a damper to reduce the over-sensitive aero-dynamic forces caused by the ultra small size of helicopter,is also equipped to facilitate manual control.The Raptor90helicopter is well suited to our UAV helicopter’s upgrading because of the fol-lowing three reasons:1.Great maneuverability:Raptor90helicopter is originallydesigned for F-3D acrobaticflight.Its agility and maneuverabil-ity are both famous in the RC hobbyflight circle.Correspond-ingly the upgraded UAV helicopter holds more control flexibility compared with those upgraded from RC helicopters developed for F-3C stableflight.Fig.1.SheLion and its virtual counterpart.546G.Cai et al./Mechatronics18(2008)545–558rge payload:The equipped OS-91SX engine is capable of gen-erating3.1ps at15,000rpm,resulting in the maximum taking-off weight up to11kg.Since the dry weight of helicopter is about4.9kg,the effective payload is up to6kg,which suits well with our budget of the weight(i.e.,3.5kg)for the onboard com-puter system and provides sufficient room for future upgrading.3.Low cost but high performance:Compared with other expensivebut same size RC helicopters such as Hirobo-90and Bergen Industrial Twin,Raptor90helicopter provides the same high qualityflight performance but at a half price.puter processor boardsFor the selection of computer processor boards,we adopt PC-104standard processor boards because of the following three fea-tures:(1)the small but uniform sizeð96mmÂ90mmÂ10mmÞ;(2)light weight(normally less than200g);and(3)anti-vibration structural design(pin-and-socket bus connection method).The most challenging issue we are facing is to ensure the working effi-ciency while strictly avoiding computational overloading and soft-ware crash during actualflight tests.Unlike the onboard system adopted in our previous UAV,HeLion,SheLion has an onboard im-age processing unit to carry out real-time process of images cap-tured by the onboard camera.As such,we separate the onboard system into two parts and employ two processor boards,of which one,called theflight control CPU,is in charge of all offlight control missions,and the other,called the image processing CPU,is paticu-larly used for image processing.By doing so,the image processing function,which is both time and computational resources consum-ing,is completely isolated from the missions related to automatic flight control and thus the overall safety of the onboard computer system is not affected.The main tasks of theflight control CPU(see Fig.2)are:(1)col-lecting data from INS/GPS and RPM sensors,sonar and servo con-trollers;(2)analyzing collected data;(3)implementingflight control laws and driving servo actuators through servo controllers;(4)logging the in-flight data to CF Card1for post-flight analysis;(5)communicating with the image processing CPU;and(6)com-municating with the ground supporting system.Although there are multipleflight missions involved,it has been proved in[5]that the computational load for normalflight tests is fairly light(lessFig.3.Raptor90RC helicopter and its virtual counterpart.Table1Specifications of Raptor90helicopterSpecifications Raptor90helicopterFull length of fuselage1410mmFull width of fuselage190mmMain rotor diameter1605mmTail rotor diameter260mmWeight4900gMaximumflight time12minG.Cai et al./Mechatronics18(2008)545–558547than 23%in the CPU usage at the peak)for a 600MHz CPU board used in HeLion.Consideration for the selection of the flight control CPU for SheLion is more on reducing the weight and power con-sumption while maintaining the system safety and working effi-cency.We choose a PC-104ATHENA,which has four RS-232serial ports,a 16-pin digital-to-analog (D/A)port,two counters/timers and runs at 600MHz.PC-104ATHENA is a 3-IN-1board,which integrates all of the necessary functions of a main processor board,a serial communication board used for data exchange with INS/GPS,servo controller and wireless modem,and a data acquisi-tion board used for data exchange with RPM sensor.As a result the weight and power consumption are greatly reduced to 30%and 50%,respectively.The image processing CPU,is only assigned tasks related to on-board image processing,which include:(1)collecting ground images;(2)analyzing image data for ground target detecting and tracking;and (3)communicating with the flight control CPU.Since the image processing job requires large amount of computational resources,a high-speed PC-104board running at 1GHz,namely,CRR-III,is selected.One PC-104standard frame grabber card is at-tached to the CRR-III for the purpose of A/D conversion and trans-formation of collected images.3.3.Avionic sensorsThere are three key avionic sensors equipped on SheLion:(1)an INS/GPS measuring all of the necessary helicopter states;(2)an ultrasonic sonar measuring the altitude in the near ground level;and (3)an RPM sensor recording the RPM of the main rotor.Their selections are based on the following.The core navigation sensor,i.e.,INS/GPS,is selected in accor-dance with the requirements on its output signals:1.The essential signals that the INS/GPS is to provide are three-axis angular rates,three-axis accelerations,three-axis magnet-ics and three-axis positions.The first three are in body frame of the UAV and the last one resides in the NED (north–east-down)frame.It is noted that the three axis Euler angles are not necessary since they can be estimated by using an extended Kalman filter (EKF)as reported in [8]and complementary filter-ing reported in [23].2.The measuring ranges of the three-axis accelerations,three-axis angular rates and three-axis magnetics are set as ±2g,±150°and ±0.7Gauss,respectively,in accordance with the specifica-tions of the commonly used commercial products.The selected threshold values are reasonable since we do not intend to cover the extreme or acrobatic flight conditions.As a result,the accel-eration,angular rate and magnetics are not to change dramati-cally during flight tests.Based on this setting,we need to carefully perform an anti-vibration design to avoid the mea-surement saturation caused by various vibration sources associ-ated with the UAV.This is to be addressed in Section 4.2.3.On the basis of meeting all of above mentioned requirements,the size,weight and power consumption of newly adopted INS/GPS should be minimized.A compact INS/GPS,namely,MNAV100CA,shown in Fig.4along with the virtual counterpart,is selected for SheLion.The key spec-ifications of this sensor are listed in Table 2,which clearly shows that all of the requirements are satisfied.Furthermore,by using MNAV100CA,the weight and power consumption of the INS/GPS sensor are greatly reduced to 5.6%and 16%,respectively,compared to those of the fully integrated INS/GPS,NAV420CA,installed on HeLion.It is to be verified in Section 5.2by various flight tests that the compact INS/GPS yields the similar level of working perfor-mance as the expensive one adopted in HeLion.The ultrasonic sonar is capable of providing altitude signal in near ground level.Due to the inaccuracy of the GPS signals,the altitude signal generated by the sonar is the key reference for auto-matic taking-off and landing processes.SheLion adopts an ultra-sonic sonar,namely,SNT-UPK2500,with a resolution in the mm range and a weight of 50g.The effective range is up to 2m,which is sufficient for automatic taking-off and landing.The RPM sensor,Futaba GV-1,is a commercial product which is commonly used in the RC hobby flight circle.To simplify the over-all design,we retain this product in SheLion but with necessary modifications to obtain the RPM number,which is originally set as an internal signal.More specifically,we connect the RPM sensor to a Schmidt Trigger and the output of the Schmidt Trigger is then sent to a counter/timer port resided in PC-104ATHENA processorboard.Fig.4.MNAV100CA and its virtual counterpart.Table 2Specifications of MNAV100CARequirementsMNAV100CAAcceleration range X/Y/Z (g)±2±2Angular rate range (°)±150±200Magnetometer range (G)±0.7±0.75GPS accuracy in CEP (m)633Update rate (Hz)P 501–100programmable Size (mm)676Â97Â7657Â45Â11Weight (g)658033Power consumption (W)6560.8548G.Cai et al./Mechatronics 18(2008)545–5583.4.Servo controllerServo controller is used to realize smooth switching between the manual control mode and automatic control mode.The requirements for the servo controller are listed as follows:1.Reliable switching function:The switching between automaticcontrol and manual control should be both fast and smooth.A particular channel must be assigned to ensure the reliability.2.Sufficient input/output channels:For most RC helicopters,fiveonboard servos are equipped to drive the helicopter.Adding an extra channel for switching function and some necessary redundancy,the input/output number must not be less than7.3.Capacity of recording servo actuator’s input signal:This function isparticularly important in initial manualflight tests.The recorded input data are essential for deriving the dynamical model of the UAV and for evaluating control performance.4.High resolution:Substantially the input-recording and servo-driving function are the A/D and D/A procedure.The resolution should be sufficiently high to ensure the data consistency andaccuracy.Thefinal selection of the servo controller,an HBC-101,is an8-input/8-output digital signal processing(DSP)board with a resolu-tion of0.009°.RS-232serial protocol is used to exchange data with PC-104ATHENA.Input channels2–6and serial port are assigned to receive the manual input signals and ATHENA-generated auto in-put signals,respectively.Channels7and8are currently not in stly,Channel1is preoccupied by the switching function. The switching signal comes from the manual control joystick.By doing so the pilot owns the highest authority to determine which side(automatic or manual input)is mapped to the output.Such a piloted-highest-control design is especially important during some unexpected situations since the pilot can immediately retrieve back the manual control to avoid accident or crash.3.5.Camera and laser pointerA camera and laser pointer are equipped onboard for ground target tracking.The camera is for collecting images of ground tar-gets and transferring back to the frame grabber for further process-ing.The main consideration for its selection is making a suitable trade-off between the resolution and the weight and volume of the camera.A compact CMOS camera with ultra small-size ð25Â25Â30mmÞ,light weight(10g)and acceptable resolution (640Â480pixels),is chosen for SheLion.The laser pointer acts as the emulation of a machine gun for attacking ground targets. For our research purpose,a commercial low-cost laser pointer witha weight of15g is selected.Its effective range is40m.3.6.Wireless modemThe wireless communication between SheLion and the ground supporting system is realized by a pair of serial wireless radio modems(one installed on the UAV and the other on the ground supporting system).We select Freewave IM-500wireless modem system with a light weight(75g),high throughput(115.2kbps), wide range(up to32km in the openfield environment)and a working frequency at2.4GHz.3.7.Onboard batteryFour WorleyParsons lithium–polymer batteries are used to pro-vide electrical power to both the onboard computer system and the onboard servo pared with other types of batteries such as Ni–Mh batteries,Ni–Cd batteries and Li–ion batteries,lith-ium–polymer batteries have the advantage of having higher power capacity,less memory effect and lighter weight.The capacity of selected batteries is to be discussed latter in Section4.3.Finally,to conclude,we summarize in Table3the key compo-nents and their specifications adopted by SheLion and its counter-part,HeLion,for easy reference and comparison.4.Systematic integration of SheLion onboard systemBased on the hardware components selected in Section3,we now proceed to carry out a systematic integration of those compo-nents for the SheLion onboard system.The procedure consists of four parts:(1)the onboard layout design;(2)the anti-vibration de-sign;(3)the power supply design;and lastly(4)electromagnetic interference(EMI)shielding design.4.1.Onboard layout designLayout design for onboard computer systems is a challenging is-sue for small-scale UAV helicopters.There is no systematic meth-ods reported in the literature to date.In what follows,we aim to propose a simple and uniform layout design approach,which can be easily followed and adopted to construct small-scale UAV heli-copters.The procedure is independent of hardware components used.The proposed approach includes the following four steps (see Fig.5;interested readers are referred to a video clip linked at .sg/~uav/wmv/3DVirtualDesign.wmv for graphical illustration):Step1:Determining the location of INS/GPS.The essential rule of this step is to mount the INS/GPS as close as possible tothe CG of the UAV helicopter to minimize the so-calledlever effect,which can cause bias on the measured acceler-ations when the UAV performs rotatory motions.Based onthe experience we gained from the construction of our ear-lier version UAV,HeLion,wefind that it is easier to controlthe UAV when the onboard system is mounted underneaththe bare helicopter.For such a layout,the general guidelineis to line up the CGs of the INS/GPS,the onboard computersystem and the basic helicopter along the z-axis of thebody frame.Since the CG location of the bare helicopteris fully known using pendulum test introduced in[7],themounting location of the INS/GPS in x–y plane of bodyframe can be determined.The offset between the CG ofthe UAV helicopter and that of the INS/GPS is only in z-axisand unavoidable.However,it can be minimized by Table3Key hardware components adopted by SheLion and HeLionComponents SheLion HeLionFlight control CPU ATHENA(600MHz,3-IN-1)CRR-III650(650MHz) Serial Board N/A OPTO-104(four serial ports) Data acquisitionboardN/A DMM-32X-AT(32A/Dinputs)Image ProcessingCPUCRR-III1G(1GHz)N/AFrame grabber Colory-104(four videochannels)N/AINS/GPS MNAV100CA NAV420CAUltrasonic sonar SNT-UPK2500(2m range)SNT-UPK2500(2m range) RPM sensor Futaba GV-1Futaba GV-1Servo controller HBC-101(8-in/8-out)HBC-101(8-in/8-out) Wireless modem Freewave IM-500(32kmrange)Freewave IM-500(32kmrange)Onboard batteries WorleyParsons Li-Po(8.4V/35W)Â2WorleyParsons Li–Po(8.4V/35W)Â2G.Cai et al./Mechatronics18(2008)545–558549carefully considering the height of onboard system and adding necessary space between the bare helicopter and the onboard system for bumping avoidance.Step 2:Determining the location of the camera and laser pointer .Theonboard camera and laser pointer are employed for ground target tracking and attacking,their mounting locations should have a good eyesight and sufficient moving space.To fulfill these requirements,they are both mounted at the most front part of the onboard system.To simplify the design,these two components are bound with each other in parallel and attached to a digital servo,which is capable of providing motion in pitch direction.In searching or attacking a ground target,the yaw direction movement is to be controlled and accomplished by the UAVitself.yout design procedure and the final onboard system.550G.Cai et al./Mechatronics 18(2008)545–558Step 3:CG balancing .The locations of the following four compo-nents,i.e.,the two PC-104processor boards,the servo con-troller,the wireless modem,and the battery packs,have also to be carefully selected.In general,the PC-104proces-sor boards and servo controller board are to be mounted at the front part for the convenience of cable/wire connection and the wireless modem is mounted on the back for the ease of wireless communications.The battery packs are also placed on the back to balance the overall CG of the onboard system.Furthermore,we also guarantee that the CG of the onboard system coincides with the CG of the INS/GPS,and the onboard system is symmetrical in both longitudinal and lateral directions.Step 4:Locating the remaining light-weight components .Theremaining light-weight (less than 50g)components include ultrasonic sonar and toggle panel,for which anti-pollution and short circuit avoidance are the mainconsid-Fig.6.Anti-vibration design for the onboard computer system (left,side view;right,frontview).Fig.7.Working point of the selected wire-rope isolators.G.Cai et al./Mechatronics 18(2008)545–558551eration.At the end,we decide to place the sonar on the landing skit and the toggle panel along with the plastic cover opposite the muffle of the helicopter.4.2.Anti-vibration designThere are three main vibration sources in the UAV helicopter:(1)the rotation of the main rotor (30.8Hz);(2)the engine (260.5Hz);and (3)the rotation of the tail rotor (143.4Hz).These frequencies are estimated based on a governed motor speed at 1850rpm.The combined vibration has a amplitude about 2g ,i.e.,19.6m/s À2,along all of the three body axes.It has potential to introduce bias to measurement data and to cause loose-of-connec-tion of mechanical components.For this reason,an anti-vibration design is necessary to ensure the overall onboard system working properly.For SheLion,four wire-rope isolators are carefully selected to realize an anti-vibration aim.They are mounted symmetrically around the CG of the onboard system (see Fig.6),and their working features are as follows:Table 4Power consumption list for SheLion UAV helicopter Hardware component Power consumption (W)Flight control CPU 12.5(at 5V DC)INS/GPS0.5(at 5V DC)Servo controller 1(at 5V DC)Wireless modem 3.9(at 12V DC)Ultrasonic sonar1(at 12V DC)Image processing CPU 19.5(at 5V DC)Frame grabber 0.5(at 5V DC)CMOS camera0.6(at 12V DC)552G.Cai et al./Mechatronics 18(2008)545–558。