电容式传感器的外文文献翻译、中英文翻译、外文翻译
光学传感器毕业论文中英文文献及翻译
英文文献及中文翻译一种精确测量倾斜角度的光学传感器摘要本文主要介绍了一种新型光学传感器,它可以同时准确地测量倾斜角或两轴倾斜角度。
这种传感器是基于激光干涉原理,因此具有很高的精度。
设计制作了一个传感器的模型来论证这个新的方法,这是一个光电传感器,传感器中没有移动的部分。
由正交于铅垂面的流动水平面提供参考面。
传感器和绝对水平面之间的角度随着被测量的物体倾斜而改变,这些变化反映在条纹图案的中心位置的转移方式。
不同的干涉条纹的中心位置随倾斜角的变化而改变。
干涉条纹图案进行记录和处理,转化为两轴、水平和垂直倾斜角度。
当使用1024*1024像素的传感器时,测量范围为700弧秒,其精度可高达+/ - 1弧秒。
关键词:倾斜角度传感器,倾斜仪,激光干涉I 介绍市场上目前有几种类型的商业倾斜角度测量传感器。
有些是角度传感器,有些是倾斜仪,它们的工作原理不同。
电解液体、电容和钟摆是现在大多数倾斜角度传感器和倾斜仪的三个主要工作原理。
在这里,我们提出了一种新的光学方法,建立了一个用激光、光学元件和图像传感器的光电传感器,它可以同时做精确的倾斜角度测量,不需要进行机械的移动,其工作原理是基于光学干涉,相干激光作为光源。
光线通过一个装满液态油的玻璃油盒。
由正交于铅垂面的流动水平面提供参考面。
当激光束穿过油箱有两束光线反射回来,一束是液体的表面产生的,另一束是容器玻璃产生的,干涉条纹就是由这两条光线形成的,条纹图案将随着倾斜角度的变化产生相应的变化,条纹图案采集和处理后将反映倾斜角度信息,光学工作原理使它不受磁场的影响。
该传感器可以同时测量两轴倾角。
流动的水平面确保了参考面是一个绝对的水平面。
高灵敏度光学干涉测量原理,保证了较高的精度。
II 原理图1说明了工作原理示意图,O点是光线扩大镜头的焦点,O点可以看作是点光源,它发出球面波。
由于地球重力的影响,液体油面始终保持水平,因此用油面作为参考平面。
该容器是玻璃材料的。
当传感器被放在目标表面时,其底部表面将连同目标对象一起倾斜。
传感器技术论文中英文对照资料外文翻译文献
传感器技术论文中英文对照资料外文翻译文献Development of New Sensor TechnologiesSensors are devices that can convert physical。
chemical。
logical quantities。
etc。
into electrical signals。
The output signals can take different forms。
such as voltage。
current。
frequency。
pulse。
etc。
and can meet the requirements of n n。
processing。
recording。
display。
and control。
They are indispensable components in automatic n systems and automatic control systems。
If computers are compared to brains。
then sensors are like the five senses。
Sensors can correctly sense the measured quantity and convert it into a corresponding output。
playing a decisive role in the quality of the system。
The higher the degree of n。
the higher the requirements for sensors。
In today's n age。
the n industry includes three parts: sensing technology。
n technology。
and computer technology。
外文翻译电容式传感器
Capacitive Sensor Operation Part 1: The BasicsPart 1 of this two-part article reviews the concepts and theory of capacitive sensing to help to optimize capacitive sensor performance. Part 2 of this article will discuss how to put these concepts to work.Noncontact capacitive sensors measure the changes in an electrical property called capacitance. Capacitance describes how two conductive objects with a space between them respond to a voltage difference applied to them. A voltage applied to the conductors creates an electric field between them, causing positive and negative charges to collect on each objectCapacitive sensors use an alternating voltage that causes the charges to continually reverse their positions. The movement of the charges creates an alternating electric current that is detected by the sensor. The amount of current flow is determined by the capacitance, and the capacitance is determined by the surface area and proximity of the conductive objects. Larger and closer objects cause greater current than smaller and more distant objects. Capacitance is also affected by the type of nonconductive material in the gap between the objects. Technically speaking, the capacitance is directly proportional to the surface area of the objects and the dielectric constant of the material between them, and inversely proportional to the distance between them as shown.:In typical capacitive sensing applications, the probe or sensor is one of the conductive objects and the target object is the other. (Using capacitive sensors to sense plastics and other insulators will be discussed in the second part of this article.) The sizes of the sensor and the target are assumed to be constant, as is the material between them. Therefore, any change in capacitance is a result of a change in the distance between the probe and the target. The electronics are calibrated to generate specific voltage changes for corresponding changes in capacitance. These voltages are scaled to represent specific changes in distance. The amount of voltage change for a given amount of distance change is called the sensitivity. A common sensitivity setting is 1.0 V/100 µm. That means that for every 100 µm change in distance, the output voltage changes exactly 1.0 V. With this calibration, a 2 V change in the output means that the target has moved 200 µm relative to the probe.Focusing the Electric FieldWhen a voltage is applied to a conductor, the electric field emanates from every surface. In a capacitive sensor, the sensing voltage is applied to the sensing area of the probe. For accuratemeasurements, the electric field from the sensing area needs to be contained within the space between the probe and the target. If the electric field is allowed to spread to other items—or other areas on the target—then a change in the position of the other item will be measured as a change in the position of the target. A technique called "guarding" is used to prevent this from happening. To create a guard, the back and sides of the sensing area are surrounded by another conductor that is kept at the same voltage as the sensing area itself. When the voltage is applied to the sensing area, a separate circuit applies the exact same voltage to the guard. Because there is no difference in voltage between the sensing area and the guard, there is no electric field between them. Any other conductors beside or behind the probe form an electric field with the guard instead of with the sensing area. Only the unguarded front of the sensing area is allowed to form an electric field with the target.DefinitionsSensitivity indicates how much the output voltage changes as a result of a change in the gap between the target and the probe. A common sensitivity is 1 V/0.1 mm. This means that for every 0.1 mm of change in the gap, the output voltage will change 1 V. When the output voltage is plotted against the gap size, the slope of the line is the sensitivity.A system's sensitivity is set during calibration. When sensitivity deviates from the ideal value this is called sensitivity error, gain error, or scaling error. Since sensitivity is the slope of a line, sensitivity error is usually presented as a percentage of slope, a comparison of the ideal slope with the actual slope.Offset error occurs when a constant value is added to the output voltage of the system. Capacitive gauging systems are usually "zeroed" during setup, eliminating any offset deviations from the original calibration. However, should the offset error change after the system is zeroed, error will be introduced into the measurement. Temperature change is the primary factor in offset error.Sensitivity can vary slightly between any two points of data. The accumulated effect of this variation is called linearity erro. The linearity specification is the measurement of how far the output varies from a straight line.To calculate the linearity error, calibration data are compared to the straight line that would best fit the points. This straight reference line is calculated from the calibration data using least squares fitting. The amount of error at the point on the calibration line furthest away from this ideal line is the linearity error. Linearity error is usually expressed in terms of percent of full scale (%/F.S.). If the error at the worst point is 0.001 mm and the full scale range of the calibration is 1 mm, the linearity error will be 0.1%.Note that linearity error does not account for errors in sensitivity. It is only a measure of the straightness of the line rather than the slope of the line. A system with gross sensitivity errors can still be very linear.Error band accounts for the combination of linearity and sensitivity errors. It is the measurement of the worst-case absolute error in the calibrated range. The error band is calculated by comparing the output voltages at specific gaps to their expected value. The worst-case error from this comparison is listed as the system's error band. In Figure 7, the worst-case error occurs for a 0.50 mm gap and the error band (in bold) is –0.010.Figure 7. Error valuesBandwidth is defined as the frequency at which the output falls to –3 dB, a frequency that is also called the cutoff frequency. A –3 dB drop in the signal level is an approximately 30% decrease. With a 15 kHz bandwidth, a change of ±1 V at low frequency will only produce a ±0.7 V change at 15 kHz. Wide-bandwidth sensors can sense high-frequency motion and provide fast-responding outputs to maximize the phase margin when used in servo-control feedback systems; however, lower-bandwidth sensors will have reduced output noise which means higher resolution. Some sensors provide selectable bandwidth to maximize either resolution or response time.Resolution is defined as the smallest reliable measurement that a system can make. The resolution of a measurement system must be better than the final accuracy the measurement requires. If you need to know a measurement within 0.02 µm, then the resolution of the measurement system must be better than 0.02 µm.The primary determining factor of resolution is electrical noise. Electrical noise appears in the output voltage causing small instantaneous errors in the output. Even when theprobe/target gap is perfectly constant, the output voltage of the driver has some small but measurable amount of noise that would seem to indicate that the gap is changing. This noise is inherent in electronic components and can be minimized, but never eliminated.If a driver has an output noise of 0.002 V with a sensitivity of 10 V/1 mm, then it has an output noise of 0.000,2 mm (0.2 µm). This means that at any instant in time, the output could have an error of 0.2 µm.The amount of noise in the output is directly related to bandwidth. Generally speaking, noise is distributed over a wide range of frequencies. If the higher frequencies are filtered before the output, the result is less noise and better resolution (Figures 8, 9). When examining resolution specifications, it is critical to know at what bandwidth the specifications apply.Capacitive Sensor Operation Part 2: System OptimizationPart 2 of this two-part article focuses on how to optimize the performance of your capacitive sensor, and to understand how target material, shape, and size will affect the sensor's response.Effects of Target SizeThe target size is a primary consideration when selecting a probe for a specific application. When the sensing electric field is focused by guarding, it creates a slightly conical field that is a projection of the sensing area. The minimum target diameter is usually 130% of the diameter of the sensing area. The further the probe is from the target, the larger the minimum target size.Range of MeasurementThe range in which a probe is useful is a function of the size of the sensing area. The greater the area, the larger the range. Because the driver electronics are designed for a certain amount of capacitance at the probe, a smaller probe must be considerably closer to the target to achieve the desired amount of capacitance. In general, the maximum gap at which a probe is useful is approximately 40% of the sensing area diameter. Typical calibrations usually keep the gap to a value considerably less than this. Although the electronics are adjustable during calibration, there is a limit to the range of adjustment.Multiple Channel SensingFrequently, a target is measured simultaneously by multiple probes. Because the system measures a changing electric field, the excitation voltagefor each probe must be synchronized or the probes will interfere with each other. If they were not synchronized, one probe would be trying to increase the electric field while another was trying to decrease it; the result would be a false reading. Driver electronics can be configured as masters or slaves; the master sets the synchronization for the slaves in multichannel systems.Effects of Target MaterialThe sensing electric field is seeking a conductive surface. Provided that the target is a conductor, capacitive sensors are not affected by the specific target material; they will measure all conductors—brass, steel, aluminum, or salt water—as the same. Because the sensing electric field stops at the surface of the conductor, target thickness does not affect the measurement中文翻译电容式传感器操作第一部分:基础 这篇文章的第一部分回顾了电容式传感器的概念和理论来帮助我们优化电容式传感器的性能。
传感器技术外文文献及中文翻译
Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque , pressure , temperature , humidity , speed , acceleration , or vibration .Traditionally ,sensors (such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a) stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features , and (c) governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems .It is essential for proper data acquisition and for the monitoring , communication , and computer control of machines and systems .Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly .Analog-to-coverter(ADC) is available for interfacing analog sensors with computers .Classifications of SensorsSensors that are of interest in manufacturing may be classified generally as follows:Machanical sensors measure such as quantities aspositions ,shape ,velocity ,force ,torque , pressure , vibration , strain , and mass .Electrical sensors measure voltage , current , charge , and conductivity .Magnetic sensors measure magnetic field ,flux , and permeablity .Thermal sensors measure temperature , flux ,conductivity , and special heat .Other types are acoustic , ultrasonic , chemical , optical , radiation , laser ,and fiber-optic .Depending on its application , a sensor may consist of metallic , nonmetallic , organic , or inorganic materials , as well as fluids ,gases ,plasmas , or semiconductors .Using the special characteristics of these materials , sensors covert the quantity or property measured to analog or digital output. The operation of an ordinary mercury thermometer , for example , is based on the difference between the thermal expansion of mercury and that of glass.Similarly , a machine part , a physical obstruction , or barrier in a space can be detected by breaking the beam of light when sensed by a photoelectric cell . A proximity sensor ( which senses and measures the distance between it and an object or a moving member of a machine ) can be based on acoustics , magnetism , capacitance , or optics . Other actuators contact the object and take appropriate action ( usually by electromechanical means ) . Sensors are essential to the conduct of intelligent robots , and are being developed with capabilities that resemble those of humans ( smart sensors , see the following ).This is America, the development of such a surgery Lin Bai an example, through the screen, through a remote control operator to control another manipulator, through the realization of the right abdominal surgery A few years ago our country theexhibition, the United States has been successful in achieving the right to the heart valve surgery and bypass surgery. This robot has in the area, caused a great sensation, but also, AESOP's surgical robot, In fact, it through some equipment to some of the lesions inspections, through a manipulator can be achieved on some parts of the operation Also including remotely operated manipulator, and many doctors are able to participate in the robot under surgery Robot doctor to include doctors with pliers, tweezers or a knife to replace the nurses, while lighting automatically to the doctor's movements linked, the doctor hands off, lighting went off, This is very good, a doctor's assistant.Tactile sensing is the continuous of variable contact forces , commonly by an array of sensors . Such a system is capable of performing within an arbitrarythree-dimensional space .has gradually shifted from manufacturing tonon-manufacturing and service industries, we are talking about the car manufacturer belonging to the manufacturing industry, However, the services sector including cleaning, refueling, rescue, rescue, relief, etc. These belong to the non-manufacturing industries and service industries, so here is compared with the industrial robot, it is a very important difference. It is primarily a mobile platform, it can move to sports, there are some arms operate, also installed some as a force sensor and visual sensors, ultrasonic ranging sensors, etc. It’s surrounding environment for the conduct of identification, to determine its campaign to complete some work, this is service robot’s one of the basic characteristicsIn visual sensing (machine vision , computer vision ) , cameral optically sense the presence and shape of the object . A microprocessor then processes the image ( usually in less than one second ) , the image is measured , and the measurements are digitized ( image recognition ) .Machine vision is suitable particularly for inaccessible parts , in hostile manufacturing environments , for measuring a large number of small features , and in situations where physics contact with the part may cause damage .Small sensors have the capability to perform a logic function , to conducttwo-way communication , and to make a decisions and take appropriate actions . The necessary input and the knowledge required to make a decision can be built into a smart sensor . For example , a computer chip with sensors can be programmed to turn a machine tool off when a cutting tool fails . Likewise , a smart sensor can stop a mobile robot or a robot arm from accidentally coming in contact with an object or people by using quantities such as distance , heat , and noise .Sensor fusion . Sensor fusion basically involves the integration of multiple sensors in such a manner where the individual data from each of the sensors ( such as force , vibration , temperature , and dimensions ) are combined to provide a higher level of information and reliability . A common application of sensor fusion occurs when someone drinks a cup of hot coffee . Although we take such a quotidian event for granted ,it readily can be seen that this process involves data input from the person's eyes , lips , tongue , and hands .Through our basic senses of sight , hearing , smell , taste , and touch , there is real-time monitoring of relative movements , positions , and temperatures . Thus if the coffee is too hot , the hand movement of the cup toward the lip is controlled and adjusted accordingly .The earliest applications of sensor fusion were in robot movement control , missile flight tracking , and similar military applications . Primarily because these activities involve movements that mimic human behavior . Another example of sensor fusion is a machine operation in which a set of different but integrated sensors monitors (a) the dimensions and surface finish of workpiece , (b) tool forces , vibrations ,and wear ,(c) the temperature in various regions of the tool-workpiece system , and (d) the spindle power .An important aspect in sensor fusion is sensor validation : the failure of one particular sensor is detected so that the control system maintains high reliability . For this application ,the receiving of redundant data from different sensors is essential . It can be seen that the receiving , integrating of all data from various sensors can be a complex problem .With advances in sensor size , quality , and technology and continued developments in computer-control systems , artificial neural networks , sensor fusion has become practical and available at low cost .Movement is relatively independent of the number of components, the equivalent of our body, waist is a rotary degree of freedom We have to be able to hold his arm, Arm can be bent, then this three degrees of freedom, Meanwhile there is a wrist posture adjustment to the use of the three autonomy, the general robot has six degrees of freedom. We will be able to space the three locations, three postures, the robot fully achieved, and of course we have less than six degrees of freedomFiber-optic sensors are being developed for gas-turbine engines . These sensors will be installed in critical locations and will monitor the conditions inside the engine , such as temperature , pressure , and flow of gas . Continuous monitoring of the signals from thes sensors will help detect possible engine problems and also provide the necessary data for improving the efficiency of the engines .传感器技术传感器一种通过检测某一参数而产生信号的装置。
电容器中英文对照外文翻译文献
电容器中英文对照外文翻译文献(文档含英文原文和中文翻译)译文:1电容器的选择本文为电化学双层电容器或超级电容器提供在一台常规电容器,简明的介绍新生的电化学双电层电容器或超级电容器。
电容器是存放电能并且协助过滤的根本电路元素。
电容器有二个主要应用; 其中之一是充电或释放电的作用。
这个作用适用于电源平流滤波电路,微型计算机备用电路和利用期间充电或释放电的定时器电路。
其他是阻拦DC 流程的作用。
这个作用适用于提取或消灭特殊频率的过滤器。
这是其中不可或缺的优秀电路所需的频率特性。
电解电容是在充分的标度商业化的下一代电容器。
他们类似电池在细胞建筑,但是阳极和负极材料依然保持不变。
他们是铝,钽和两个陶瓷电容电解质的地方与他们所使用的液体固体分离器/ 对称的电极。
电化学电容器(EC),往往被称为超级电容器或超级电容,存储电荷的双层电荷在1层表面电解质界面,主要在高电位表面的碳。
由于高电位表面是薄的双重层,所以这些设备可以有一个非常高的比和体积电容。
这使得他们能够结合以前无法实现的电容用无限的电荷密度/放电循环寿命。
每单元的工作电压,只受击穿电位电解质的影响,通常<1或“<3伏的每个细胞水性或有机电解质分别。
该存储的概念电力能源双电层这是形成于界面之间的固体电解质和一直都知道自19世纪末期。
第一电气设备使用双层充电储存在报告1957年H.I.贝克尔的通用电气(美国专利2800616)。
不幸的是,贝克尔的设备是不切实际的,同样一个充斥电池,电极都需要沉浸在一个容器电解质,并且该设备从未商业化。
贝克尔那样做了,但是随后发现电容值已经被标准石油化学家公司俄亥俄州(索奥)的罗伯特A赖特迈尔发明并且现在正在普遍使用。
他的专利(美国3288641),在1962年年底提出并获1966年11月,和一个后续专利(美国专利3536963)由资深研究员索奥唐纳德L.布斯在1970年,形式为基础随后的专利和期刊数百文章涉及ec技术的所有方面。
电容式传感器中英文翻译资料毕业设计用
Capacitive Sensor Operation Part 1: The BasicsPart 1 of this two-part article reviews the concepts and theory of capacitive sensing to help to optimize capacitive sensor performance. Part 2 of this article will discuss how to put these concepts to work.Noncontact capacitive sensors measure the changes in an electrical property called capacitance. Capacitance describes how two conductive objects with a space between them respond to a voltage difference applied to them. A voltage applied to the conductors creates an electric field between them, causing positive and negative charges to collect on each objectCapacitive sensors use an alternating voltage that causes the charges to continually reverse their positions. The movement of the charges creates an alternating electric current that is detected by the sensor. The amount of current flow is determined by the capacitance, and the capacitance is determined by the surface area and proximity of the conductive objects. Larger and closer objects cause greater current than smaller and more distant objects. Capacitance is also affected by the type of nonconductive material in the gap between the objects. Technically speaking, the capacitance is directly proportional to the surface area of the objects and the dielectric constant of the material between them, and inversely proportional to the distance between them as shown.:In typical capacitive sensing applications, the probe or sensor is one of the conductive objects and the target object is the other. (Using capacitive sensors to sense plastics and other insulators will be discussed in the second part of this article.) The sizes of the sensor and the target are assumed to be constant, as is the material between them. Therefore, any change in capacitance is a result of a change in the distance between the probe and the target. The electronics are calibrated to generate specific voltage changes for corresponding changes in capacitance. These voltages are scaled to represent specific changes in distance. The amount of voltage change for a given amount of distance change is called the sensitivity. A common sensitivity setting is 1.0 V/100 µm. That means that for every 100 µm change in distance, the output voltage changes exactly 1.0 V. With this calibration, a 2 V change in the output means that the target has moved 200 µm relative to the probe.Focusing the Electric FieldWhen a voltage is applied to a conductor, the electric field emanates from every surface. In a capacitive sensor, the sensing voltage is applied to the sensing area of the probe. For accurate measurements, the electric field from the sensing area needs to be contained within the space between the probe and the target. If the electric field is allowed to spread to other items—or other areas on the target—then a change in the position of the other item will be measured as a change in the position of the target. A technique called "guarding" is used to prevent this from happening. To create a guard, the back and sides of the sensing area are surrounded by another conductor that is kept at the same voltage as the sensing area itself. When the voltage is applied to the sensing area, a separate circuit applies the exact same voltage to the guard. Because there is no difference in voltage between the sensing area and the guard, there is no electric field between them. Any other conductors beside or behind the probe form an electric field with the guard instead of with the sensing area. Only the unguarded front of the sensing area is allowed to form an electric field with the target.DefinitionsSensitivity indicates how much the output voltage changes as a result of a change in the gap between the target and the probe. A common sensitivity is 1 V/0.1 mm. This means that for every 0.1 mm of change in the gap, the output voltage will change 1 V. When the output voltage is plotted against the gap size, the slope of the line is the sensitivity.A system's sensitivity is set during calibration. When sensitivity deviates from the ideal value this is called sensitivity error, gain error, or scaling error. Since sensitivity is the slope of a line, sensitivity error is usually presented as a percentage of slope, a comparison of the ideal slope with the actual slope.Offset error occurs when a constant value is added to the output voltage of the system. Capacitive gauging systems are usually "zeroed" during setup, eliminating any offset deviations from the original calibration. However, should the offset error change after the system is zeroed, error will be introduced into the measurement. Temperature change is the primary factor in offset error.Sensitivity can vary slightly between any two points of data. The accumulated effect of this variation is called linearity erro. The linearity specification is the measurement of how far the output varies from a straight line.To calculate the linearity error, calibration data are compared to the straight line that would best fit the points. This straight reference line is calculated from the calibration data using least squares fitting. The amount of error at the point on the calibration line furthest away from this ideal line is the linearity error. Linearity error is usually expressed in terms ofpercent of full scale (%/F.S.). If the error at the worst point is 0.001 mm and the full scale range of the calibration is 1 mm, the linearity error will be 0.1%.Note that linearity error does not account for errors in sensitivity. It is only a measure of the straightness of the line rather than the slope of the line. A system with gross sensitivity errors can still be very linear.Error band accounts for the combination of linearity and sensitivity errors. It is the measurement of the worst-case absolute error in the calibrated range. The error band is calculated by comparing the output voltages at specific gaps to their expected value. The worst-case error from this comparison is listed as the system's error band. In Figure 7, the worst-case error occurs for a 0.50 mm gap and the error band (in bold) is –0.010.Gap (mm)Expected Value (VDC)Actual Value VDC)Error (mm) 0.50 –10.000 –9.800 –0.0100.75 –5.000 –4.900 –0.0051.00 0.000 0.000 0.0001.25 5.000 5.000 0.0001.50 10.000 10.100 0.005Figure 7. Error valuesBandwidth is defined as the frequency at which the output falls to –3 dB, a frequency that is also called the cutoff frequency. A –3 dB drop in the signal level is an approximately 30% decrease. With a 15 kHz bandwidth, a change of ±1 V at low frequency will only produce a ±0.7 V change at 15 kHz. Wide-bandwidth sensors can sense high-frequency motion and provide fast-responding outputs to maximize the phase margin when used in servo-control feedback systems; however, lower-bandwidth sensors will have reduced output noise which means higher resolution. Some sensors provide selectable bandwidth to maximize either resolution or response time.Resolution is defined as the smallest reliable measurement that a system can make. The resolution of a measurement system must be better than the final accuracy the measurement requires. If you need to know a measurement within 0.02 µm, then the resolution of the measurement system must be better than 0.02 µm.The primary determining factor of resolution is electrical noise. Electrical noise appears in the output voltage causing small instantaneous errors in the output. Even when theprobe/target gap is perfectly constant, the output voltage of the driver has some small butmeasurable amount of noise that would seem to indicate that the gap is changing. This noise is inherent in electronic components and can be minimized, but never eliminated.If a driver has an output noise of 0.002 V with a sensitivity of 10 V/1 mm, then it has an output noise of 0.000,2 mm (0.2 µm). This means that at any instant in time, the output could have an error of 0.2 µm.The amount of noise in the output is directly related to bandwidth. Generally speaking, noise is distributed over a wide range of frequencies. If the higher frequencies are filtered before the output, the result is less noise and better resolution (Figures 8, 9). When examining resolution specifications, it is critical to know at what bandwidth the specifications apply.Capacitive Sensor Operation Part 2: System OptimizationPart 2 of this two-part article focuses on how to optimize the performance of your capacitive sensor, and to understand how target material, shape, and size will affect the sensor's response.Effects of Target SizeThe target size is a primary consideration when selecting a probe for a specific application. When the sensing electric field is focused by guarding, it creates a slightly conical field that is a projection of the sensing area. The minimum target diameter is usually 130% of the diameter of the sensing area. The further the probe is from the target, the larger the minimum target size.Range of MeasurementThe range in which a probe is useful is a function of the size of the sensing area. The greater the area, the larger the range. Because the driver electronics are designed for a certain amount of capacitance at the probe, a smaller probe must be considerably closer to the target to achieve the desired amount of capacitance. In general, the maximum gap at which a probe is useful is approximately 40% of the sensing area diameter. Typical calibrations usually keep the gap to a value considerably less than this. Although the electronics are adjustable during calibration, there is a limit to the range of adjustment.Multiple Channel SensingFrequently, a target is measured simultaneously by multiple probes. Because the system measures a changing electric field, the excitation voltagefor each probe must be synchronized or the probes will interfere with each other. If they were not synchronized, one probe would be trying to increase the electric field while another was trying to decrease it; the result wouldbe a false reading. Driver electronics can be configured as masters or slaves; the master sets the synchronization for the slaves in multichannel systems.Effects of Target MaterialThe sensing electric field is seeking a conductive surface. Provided that the target is a conductor, capacitive sensors are not affected by the specific target material; they will measure all conductors—brass, steel, aluminum, or salt water—as the same. Because the sensing electric field stops at the surface of the conductor, target thickness does not affect the measurement中文翻译电容式传感器操作第一部分:基础 这篇文章的第一部分回顾了电容式传感器的概念和理论来帮助我们优化电容式传感器的性能。
传感器的基础知识中英文对照外文翻译文献
中英文对照外翻译Basic knowledge of transducersA transducer is a device which converts the quantity being measured into an optical, mechanical, or-more commonly-electrical signal. The energy-conversion process that takes place is referred to as transduction.Transducers are classified according to the transduction principle involved and the form of the measured. Thus a resistance transducer for measuring displacement is classified as a resistance displacement transducer. Other classification examples are pressure bellows, force diaphragm, pressure flapper-nozzle, and so on.1、Transducer ElementsAlthough there are exception ,most transducers consist of a sensing element and a conversion or control element. For example, diaphragms,bellows,strain tubes and rings, bourdon tubes, and cantilevers are sensing elements which respond to changes in pressure or force and convert these physical quantities into a displacement. This displacement may then be used to change an electrical parameter such as voltage, resistance, capacitance, or inductance. Such combination of mechanical and electrical elements form electromechanical transducing devices or transducers. Similar combination can be made for other energy input such as thermal. Photo, magnetic and chemical,giving thermoelectric, photoelectric,electromaanetic, and electrochemical transducers respectively.2、Transducer SensitivityThe relationship between the measured and the transducer output signal is usually obtained by calibration tests and is referred to as the transducer sensitivity K1= output-signal increment / measured increment . In practice, the transducer sensitivity is usually known, and, by measuring the output signal, the input quantity is determined from input= output-signal increment / K1.3、Characteristics of an Ideal TransducerThe high transducer should exhibit the following characteristicsa) high fidelity-the transducer output waveform shape be a faithful reproduction of the measured; there should be minimum distortion.b) There should be minimum interference with the quantity being measured; the presence of the transducer should not alter the measured in any way.c) Size. The transducer must be capable of being placed exactly where it is needed.d) There should be a linear relationship between the measured and the transducer signal.e) The transducer should have minimum sensitivity to external effects, pressure transducers,for example,are often subjected to external effects such vibration and temperature.f) The natural frequency of the transducer should be well separated from the frequency and harmonics of the measurand.4、Electrical TransducersElectrical transducers exhibit many of the ideal characteristics. In addition they offer high sensitivity as well as promoting the possible of remote indication or mesdurement. Electrical transducers can be divided into two distinct groups:a) variable-control-parameter types,which include:i)resistanceii) capacitanceiii) inductanceiv) mutual-inductance typesThese transducers all rely on external excitation voltage for their operation.b) self-generating types,which includei) electromagneticii)thermoelectriciii)photoemissiveiv)piezo-electric typesThese all themselves produce an output voltage in response to the measurand input and their effects are reversible. For example, a piezo-electric transducer normally produces an output voltage in response to the deformation of a crystalline material; however, if an alternating voltage is applied across the material, the transducer exhibits the reversible effect by deforming or vibrating at the frequency of the alternating voltage.5、Resistance TransducersResistance transducers may be divided into two groups, as follows:i) Those which experience a large resistance change, measured by using potential-divider methods. Potentiometers are in this group.ii)Those which experience a small resistance change, measured by bridge-circuit methods. Examples of this group include strain gauges and resistance thermometers.5.1 PotentiometersA linear wire-wound potentiometer consists of a number of turns resistance wire wound around a non-conducting former, together with a wiping contact which travels over the barwires. The construction principles are shown in figure which indicate that the wiperdisplacement can be rotary, translational, or a combination of both to give a helical-type motion. The excitation voltage may be either a.c. or d.c. and the output voltage is proportional to the input motion, provided the measuring device has a resistance which is much greater than the potentiometer resistance.Such potentiometers suffer from the linked problem of resolution and electrical noise. Resolution is defined as the smallest detectable change in input and is dependent on thecross-sectional area of the windings and the area of the sliding contact. The output voltage is thus a serials of steps as the contact moves from one wire to next.Electrical noise may be generated by variation in contact resistance, by mechanical wear due to contact friction, and by contact vibration transmitted from the sensing element. In addition, the motion being measured may experience significant mechanical loading by the inertia and friction of the moving parts of the potentiometer. The wear on the contacting surface limits the life of a potentiometer to a finite number of full strokes or rotations usually referred to in the manufacture’s specification as the ‘number of cycles of life expectancy’, a typical value being 20*1000000 cycles.The output voltage V0 of the unload potentiometer circuit is determined as follows. Let resistance R1= xi/xt *Rt where xi = input displacement, xt= maximum possible displacement, Rt total resistance of the potentiometer. Then output voltage V0= V*R1/(R1+( Rt-R1))=V*R1/Rt=V*xi/xt*Rt/Rt=V*xi/xt. This shows that there is a straight-line relationship between output voltage and input displacement for the unloaded potentiometer.It would seen that high sensitivity could be achieved simply by increasing the excitation voltage V. however, the maximum value of V is determined by the maximum power dissipation P of the fine wires of the potentiometer winding and is given by V=(PRt)1/2 .5.2 Resistance Strain GaugesResistance strain gauges are transducers which exhibit a change in electrical resistance in response to mechanical strain. They may be of the bonded or unbonded variety .a) bonded strain gaugesUsing an adhesive, these gauges are bonded, or cemented, directly on to the surface of the body or structure which is being examined.Examples of bonded gauges arei) fine wire gauges cemented to paper backingii) photo-etched grids of conducting foil on an epoxy-resin backingiii)a single semiconductor filament mounted on an epoxy-resin backing with copper or nickel leads.Resistance gauges can be made up as single elements to measuring strain in one direction only,or a combination of elements such as rosettes will permit simultaneous measurements in more than one direction.b) unbonded strain gaugesA typical unbonded-strain-gauge arrangement shows fine resistance wires stretched around supports in such a way that the deflection of the cantilever spring system changes the tension in the wires and thus alters the resistance of wire. Such an arrangement may be found in commercially available force, load, or pressure transducers.5.3 Resistance Temperature TransducersThe materials for these can be divided into two main groups:a) metals such as platinum, copper, tungsten, and nickel which exhibit and increase in resistance as the temperature rises; they have a positive temperature coefficient of resistance.b) semiconductors, such as thermistors which use oxides of manganese, cobalt, chromium, or nickel. These exhibit large non-linear resistance changes with temperature variation and normally have a negative temperature coefficient of resistance.a) metal resistance temperature transducersThese depend, for many practical purpose and within a narrow temperature range, upon the relationship R1=R0*[1+a*(b1-b2)] where a coefficient of resistance in ℃-1,and R0 resistance in ohms at the reference temperature b0=0℃ at the reference temperature range ℃.The international practical temperature scale is based on the platinum resistance thermometer, which covers the temperature range -259.35℃ to 630.5℃.b) thermistor resistance temperature transducersThermistors are temperature-sensitive resistors which exhibit large non-liner resistance changes with temperature variation. In general, they have a negative temperature coefficient. For small temperature increments the variation in resistance is reasonably linear; but, if large temperature changes are experienced, special linearizing techniques are used in the measuring circuits to produce a linear relationship of resistance against temperature.Thermistors are normally made in the form of semiconductor discs enclosed in glass vitreous enamel. Since they can be made as small as 1mm,quite rapid response times are possible.5.4 Photoconductive CellsThe photoconductive cell , uses a light-sensitive semiconductor material. The resistance between the metal electrodes decrease as the intensity of the light striking the semiconductor increases. Common semiconductor materials used for photo-conductive cells are cadmium sulphide, lead sulphide, and copper-doped germanium.The useful range of frequencies is determined by material used. Cadmium sulphide is mainly suitable for visible light, whereas lead sulphide has its peak response in the infra-red regionand is, therefore , most suitable for flame-failure detection and temperature measurement. 5.5 Photoemissive CellsWhen light strikes the cathode of the photoemissive cell are given sufficient energy to arrive the cathode. The positive anode attracts these electrons, producing a current which flows through resistor R and resulting in an output voltage V.Photoelectrically generated voltage V=Ip.RlWhere Ip=photoelectric current(A),and photoelectric current Ip=Kt.BWhere Kt=sensitivity (A/im),and B=illumination input (lumen)Although the output voltage does give a good indication of the magnitude of illumination, the cells are more often used for counting or control purpose, where the light striking the cathode can be interrupted.6、Capacitive TransducersThe capacitance can thus made to vary by changing either the relative permittivity, the effective area, or the distance separating the plates. The characteristic curves indicate that variations of area and relative permittivity give a linear relationship only over a small range of spacings. Thus the sensitivity is high for small values of d. Unlike the potentionmeter, the variable-distance capacitive transducer has an infinite resolution making it most suitable for measuring small increments of displacement or quantities which may be changed to produce a displacement.7、Inductive TransducersThe inductance can thus be made to vary by changing the reluctance of the inductive circuit. Measuring techniques used with capacitive and inductive transducers:a)A.C. excited bridges using differential capacitors inductors.b)A.C. potentiometer circuits for dynamic measurements.c) D.C. circuits to give a voltage proportional to velocity for a capacitor.d) Frequency-modulation methods, where the change of C or L varies the frequency of an oscillation circuit.Important features of capacitive and inductive transducers are as follows:i)resolution infiniteii) accuracy+- 0.1% of full scale is quotediii)displacement ranges 25*10-6 m to 10-3miv) rise time less than 50us possibleTypical measurands are displacement, pressure, vibration, sound, and liquid level.8、Linear Variable-differential Ttransformer9、Piezo-electric Transducers10、Electromagnetic Transducers11、Thermoelectric Transducers12、Photoelectric Cells13、Mechanical Transducers and Sensing Elements传感器的基础知识传感器是一种把被测量转换为光的、机械的或者更平常的电信号的装置。
传感器中英文介绍
. sensorssensors(English name: transducer/sensor) is a kind of detection device, can feel the measured information, and will feel information transformation according to certain rule become electrical signal output, or other form of information needed to satisfy the information transmission, processing, storage, display, record and control requirements.Sensor's features include: miniaturization, digital, intelligent, multi-functional, systematic and network. It is the first step of automatic detection and automatic control. The existence and development of the sensor, let objects have sensory, such as touch, taste and smell let objects become live up slowly. Usually according to its basic cognitive functions are divided into temperature sensor, light sensor, gas sensor, force sensor, magnetic sensor, moisture sensor, acoustic sensor, radiation sensitive element, color sensor and sensor etc. 10 major categories.temperature transducerTemperature sensors (temperature transducer) refers to can feel temperature translates into usable output signal of the sensor. The temperature sensor is the core part of the temperature measuring instrument, wide variety. According to measuring methods could be divided into two types: contact and non-contact, according to the sensor material and electronic component features divided into two categories, thermal resistance and thermocouple.1 principle of thermocoupleThermocouple is composed of two different materials of metal wire, the welded together at the end. To measure the heating part of the environment temperature, can accurately know the temperature of the hot spots. Because it must have two different material of the conductor, so called the thermocouple. Different material to make the thermocouple used in different temperature range, their sensitivity is also each are not identical. The sensitivity of thermocouple refers to add 1 ℃hot spot temperature changes, the output variation of potential difference. For most of the metal material support thermocouple, this value about between 5 ~ 40 microvolt / ℃.As a result of the thermocouple temperature sensor sensitivity has nothing to do with the thickness of material, use very fine material also can make the temperature sensor. Also due to the production of thermocouple metal materials have good ductility, the slight temperature measuring element has high response speed, can measure the process of rapid change.Its advantages are:(1)high precision measurement. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium.(2)the measurement range. Commonly used thermocouple from 1600 ℃to 50 ℃ ~ + sustainable measurement, some special thermocouple minimum measurable to - 269 ℃ (e.g., gold iron nickel chrome), the highest measurable to + 2800 ℃ (such as tungsten rhenium).(3) simple structure, easy to use. Thermocouple is usually composed of two different kinds of metal wire, but is not limited by the size and the beginning of, outside has protective casing, so very convenient to use. The thermocouple type and structure of the form.2. The thermocouple type and structure formation(1)the types of thermocoupleThe commonly used thermocouple could be divided into two types: standard thermocouple and non-standard thermocouple. Standard thermocouple refers to the national standard specifies its thermoelectric potential and the relationship between temperature, permissible error, and a unified standard score table of thermocouple, it has with matching display instrument to choose from. Rather than a standard thermocouple or on the order of magnitude less than the range to use standardized thermocouple, in general, there is no uniform standard, it is mainly used for measurement of some special occasions.Standardized thermocouple is our country from January 1, 1988, thermocouple and thermal resistance of all production according to IEC international standard, and specify the S, B, E, K, R, J, T seven standardization thermocouple type thermocouple for our country unified design.(2)to ensure that the thermocouple is reliable, steady work, the structure of thermocouple requirements are as follows:①of the two thermocouple thermal electrode welding must be strong;②two hot electrode should be well insulated between each other, in case of short circuit;③compensation wires connected to the free cod of a thermocouple to convenient and reliable;④protect casing thermal electrodes should be able to make sufficient isolation and harmful medium.3.The thermocouple cold end temperature compensationDue to the thermocouple materials are generally more expensive (especiallywhen using precious metals), and the temperature measurement points are generally more far, the distance to the instrument in order to save materials, reduce cost, usually adopt the compensating conductor) (the free end of the cold junction of the thermocouple to the steady control of indoor temperature, connected to the meter terminals. It must be pointed out that the role of the thermocouple compensation wire extension hot electrode, so that only moved to the control room of the cold junction of the thermocouple instrument on the terminal, it itself does not eliminate the cold end temperature change on the influence of temperature, cannot have the compensation effect. So, still need to take some of the other correction method to compensate of the cold end temperature especially when t0 indicates influence on measuring temperature 0 ℃.Must pay attention to when using thermocouple compensating conductor model match, cannot be wrong polarity, compensation conductor should be connected to the thermocouple temperature should not exceed 100 ℃.传感器传感器(英文名称:transducer/sensor)是一种检测装置,能感受到被测量的信息,并能将感受到的信息,按一定规律变换成为电信号或其他所需形式的信息输出,以满足信息的传输、处理、存储、显示、记录和控制等要求。
传感器技术外文文献及中文翻译
传感器技术外文文献及中文翻译Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque , pressure , temperature , humidity , speed , acceleration , or vibration .Traditionally ,sensors (such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a) stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features , and (c) governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems .It is essential for proper data acquisition and for the monitoring , communication , and computer control of machines and systems .Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly .Analog-to-coverter(ADC) is available for interfacing analog sensors with computers .Classifications of SensorsSensors that are of interest in manufacturing may be classified generally as follows:Machanical sensors measure such as quantities aspositions ,shape ,velocity ,force ,torque , pressure , vibration , strain , andmass .Electrical sensors measure voltage , current , charge , and conductivity .Magnetic sensors measure magnetic field ,flux , and permeablity .Thermal sensors measure temperature , flux ,conductivity , and special heat .Other types are acoustic , ultrasonic , chemical , optical , radiation ,laser ,and fiber-optic .Depending on its application , a sensor may consist of metallic , nonmetallic , organic , or inorganic materials , as well as fluids ,gases ,plasmas , or semiconductors .Using the special characteristics of these materials , sensors covert the quantity or property measured to analog or digital output. The operation of an ordinary mercury thermometer , for example , is based on the difference between the thermal expansion of mercury and that of glass.Similarly , a machine part , a physical obstruction , or barrier in a space can be detected by breaking the beam of light when sensed by a photoelectric cell . A proximity sensor ( which senses and measures the distance between it and an object or a moving member of a machine ) can be based on acoustics , magnetism , capacitance , or optics . Other actuators contact the object and take appropriate action ( usually by electromechanical means ) . Sensors are essential to the conduct of intelligent robots , and are being developed with capabilities that resemble those of humans ( smart sensors , see the following ).This is America, the development of such a surgery Lin Bai an example,through the screen, through a remote control operator to control another manipulator, through the realization of the right abdominal surgery A few years ago our country the exhibition, the United States has been successful in achieving the right to the heart valve surgery and bypass surgery. This robot has in the area, caused a great sensation, but also, AESOP's surgical robot, In fact, it through some equipment to some of the lesions inspections, through a manipulator can be achieved on some parts of the operation Also including remotely operated manipulator, and many doctors are able to participate in the robot under surgery Robot doctor to include doctors with pliers, tweezers or a knife to replace the nurses, while lighting automatically to the doctor's movements linked, the doctor hands off, lighting went off, This is very good, a doctor's assistant.Tactile sensing is the continuous of variable contact forces , commonly by an array of sensors . Such a system is capable of performing within an arbitrary three-dimensional space .has gradually shifted from manufacturing tonon-manufacturing and service industries, we are talking about the car manufacturer belonging to the manufacturing industry, However, the services sector including cleaning, refueling, rescue, rescue, relief, etc. These belong to the non-manufacturing industries and service industries, so here is compared with the industrial robot, it is a very important difference. It is primarily a mobile platform, it can move to sports, there are some arms operate, also installed some as a force sensor and visual sensors, ultrasonic ranging sensors, etc. It’s surrounding environment for the conduct of identification, to determine its campaign to complete some work, this is service robot’s one of the basic characteristicsIn visual sensing (machine vision , computer vision ) , cameral optically sense the presence and shape of the object . A microprocessor then processes the image ( usually in less than one second ) , the image is measured , and the measurements are digitized ( image recognition ) .Machine vision is suitable particularly for inaccessible parts , in hostile manufacturing environments , for measuring a large number of small features , and in situations where physics contact with the part may cause damage .Small sensors have the capability to perform a logic function , to conduct two-way communication , and to make a decisions and take appropriate actions . The necessary input and the knowledge required to make a decision can be built into a smart sensor . For example , a computer chip with sensors can be programmed to turn a machine tool off when a cutting tool fails . Likewise , a smart sensor can stop a mobile robot or a robot arm from accidentally coming in contact with an object or people by using quantities such as distance , heat , and noise .Sensor fusion . Sensor fusion basically involves the integration of multiple sensors in such a manner where the individual data from each of the sensors ( such as force , vibration , temperature , and dimensions ) are combined to provide a higher level of information and reliability . A common application ofsensor fusion occurs when someone drinks a cup of hot coffee . Although we take such a quotidian event for granted ,it readily can be seen that this process involves data input from the person's eyes , lips , tongue , and hands .Through our basic senses of sight , hearing , smell , taste , and touch , there is real-time monitoring of relative movements , positions , and temperatures . Thus if the coffee is too hot , the hand movement of the cup toward the lip is controlled and adjusted accordingly .The earliest applications of sensor fusion were in robot movement control , missile flight tracking , and similar military applications . Primarily because these activities involve movements that mimic human behavior . Another example of sensor fusion is a machine operation in which a set of different but integrated sensors monitors (a) the dimensions and surface finish of workpiece , (b) tool forces , vibrations ,and wear ,(c) the temperature in various regions of the tool-workpiece system , and (d) the spindle power .An important aspect in sensor fusion is sensor validation : the failure of one particular sensor is detected so that the control system maintains high reliability . For this application ,the receiving of redundant data from different sensors is essential . It can be seen that the receiving , integrating of all data from various sensors can be a complex problem .With advances in sensor size , quality , and technology and continued developments in computer-control systems , artificial neural networks , sensor fusion has become practical and available at low cost .Movement is relatively independent of the number of components, the equivalent of our body, waist is a rotary degree of freedom We have to be able to hold his arm, Arm can be bent, then this three degrees of freedom, Meanwhile there is a wrist posture adjustment to the use of the three autonomy, the general robot has six degrees of freedom. We will be able to space the three locations, three postures, the robot fully achieved, and of course we have less than six degrees of freedom Fiber-optic sensors are being developed for gas-turbine engines . These sensors will be installed in critical locations and will monitor the conditions inside the engine , such as temperature , pressure , and flow of gas . Continuous monitoring of the signals from thes sensors will help detect possible engine problems and also provide the necessary data for improving the efficiency of the engines .传感器技术传感器一种通过检测某一参数而产生信号的装置。
传感器技术4-电容式传感器-中英对照
C AC 0 C BC 0
0 r (工作原理、结构及特性
对图(b)有
C AC 0 C BC 0
0 r lr 0
(4-18)
上两式中 α ——初始位置时一组极板相 互覆盖有效面积所包的角度(或所对的圆心 角);δ 0、ε r同前。 当动极板C随角位移(Δα)输入而摆动时 两组电容值一增一减,差动输出。
2
4.1 工作原理、结构及特性
由式(4-9)可见, δ0的减小会导致非线性误差增大;δ0过小 还可能引起电容器击穿(break down)或短路(short circuit)。 为此,极板间可采用高介电常数(permittivity)的材料(云母 (Mica)、塑料膜(plastic film)等)作介质,如图4.4所示。设 两种介质的相对介电质常数为εr1 (空气:εr1=1)、εr2, 相应的介质厚度为δ1、δ2,则有
4.1 工作原理、结构及特性
若电介质(dielectric)1为空气(εr1=1),当l=0时传感器的初 始电容为:
C0 0 r l 0 b0 / 0
当介质2进入极间l后引起电容的相对变化为
C C C 0 r 2 1 l C0 C0 l0
4.1 工作原理、结构及特性
4.1.1 变极距型电容传感器
图4-1为这种传感器的原理图。当传感器的εr和A为常数,初 始极距为δ0 ,由式(4-1)可知其初始电容量C0为
C0 0 r A / 0
(4-2)
图4.1 变极距型电容传感器原理图
4.1 工作原理、结构及特性
4.1 工作原理、结构及特性
图4-7 变面积型差动式结构 (a)扇形平板结构;(b)柱面板结构
传感器技术外文文献及中文翻译讲课讲稿
Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque , pressure , temperature , humidity , speed , acceleration , or vibration .Traditionally ,sensors (such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a) stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features , and (c) governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems .It is essential for proper data acquisition and for the monitoring , communication , and computer control of machines and systems .Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly .Analog-to-coverter(ADC) is available for interfacing analog sensors with computers .Classifications of SensorsSensors that are of interest in manufacturing may be classified generally as follows:Machanical sensors measure such as quantities aspositions ,shape ,velocity ,force ,torque , pressure , vibration , strain , and mass .Electrical sensors measure voltage , current , charge , and conductivity .Magnetic sensors measure magnetic field ,flux , and permeablity .Thermal sensors measure temperature , flux ,conductivity , and special heat .Other types are acoustic , ultrasonic , chemical , optical , radiation , laser ,and fiber-optic .Depending on its application , a sensor may consist of metallic , nonmetallic , organic , or inorganic materials , as well as fluids ,gases ,plasmas , or semiconductors .Using the special characteristics of these materials , sensors covert the quantity or property measured to analog or digital output. The operation of an ordinary mercury thermometer , for example , is based on the difference between the thermal expansion of mercury and that of glass.Similarly , a machine part , a physical obstruction , or barrier in a space can be detected by breaking the beam of light when sensed by a photoelectric cell . A proximity sensor ( which senses and measures the distance between it and an object or a moving member of a machine ) can be based on acoustics , magnetism , capacitance , or optics . Other actuators contact the object and take appropriate action ( usually by electromechanical means ) . Sensors are essential to the conduct of intelligent robots , and are being developed with capabilities that resemble those of humans ( smart sensors , see the following ).This is America, the development of such a surgery Lin Bai an example, through the screen, through a remote control operator to control another manipulator, through the realization of the right abdominal surgery A few years ago our country theexhibition, the United States has been successful in achieving the right to the heart valve surgery and bypass surgery. This robot has in the area, caused a great sensation, but also, AESOP's surgical robot, In fact, it through some equipment to some of the lesions inspections, through a manipulator can be achieved on some parts of the operation Also including remotely operated manipulator, and many doctors are able to participate in the robot under surgery Robot doctor to include doctors with pliers, tweezers or a knife to replace the nurses, while lighting automatically to the doctor's movements linked, the doctor hands off, lighting went off, This is very good, a doctor's assistant.Tactile sensing is the continuous of variable contact forces , commonly by an array of sensors . Such a system is capable of performing within an arbitrarythree-dimensional space .has gradually shifted from manufacturing tonon-manufacturing and service industries, we are talking about the car manufacturer belonging to the manufacturing industry, However, the services sector including cleaning, refueling, rescue, rescue, relief, etc. These belong to the non-manufacturing industries and service industries, so here is compared with the industrial robot, it is a very important difference. It is primarily a mobile platform, it can move to sports, there are some arms operate, also installed some as a force sensor and visual sensors, ultrasonic ranging sensors, etc. It’s surrounding environment for the conduct of identification, to determine its campaign to complete some work, this is service robot’s one of the basic characteristicsIn visual sensing (machine vision , computer vision ) , cameral optically sense the presence and shape of the object . A microprocessor then processes the image ( usually in less than one second ) , the image is measured , and the measurements are digitized ( image recognition ) .Machine vision is suitable particularly for inaccessible parts , in hostile manufacturing environments , for measuring a large number of small features , and in situations where physics contact with the part may cause damage .Small sensors have the capability to perform a logic function , to conducttwo-way communication , and to make a decisions and take appropriate actions . The necessary input and the knowledge required to make a decision can be built into a smart sensor . For example , a computer chip with sensors can be programmed to turn a machine tool off when a cutting tool fails . Likewise , a smart sensor can stop a mobile robot or a robot arm from accidentally coming in contact with an object or people by using quantities such as distance , heat , and noise .Sensor fusion . Sensor fusion basically involves the integration of multiple sensors in such a manner where the individual data from each of the sensors ( such as force , vibration , temperature , and dimensions ) are combined to provide a higher level of information and reliability . A common application of sensor fusion occurs when someone drinks a cup of hot coffee . Although we take such a quotidian event for granted ,it readily can be seen that this process involves data input from the person's eyes , lips , tongue , and hands .Through our basic senses of sight , hearing , smell , taste , and touch , there is real-time monitoring of relative movements , positions , and temperatures . Thus if the coffee is too hot , the hand movement of the cup toward the lip is controlled and adjusted accordingly .The earliest applications of sensor fusion were in robot movement control , missile flight tracking , and similar military applications . Primarily because these activities involve movements that mimic human behavior . Another example of sensor fusion is a machine operation in which a set of different but integrated sensors monitors (a) the dimensions and surface finish of workpiece , (b) tool forces , vibrations ,and wear ,(c) the temperature in various regions of the tool-workpiece system , and (d) the spindle power .An important aspect in sensor fusion is sensor validation : the failure of one particular sensor is detected so that the control system maintains high reliability . For this application ,the receiving of redundant data from different sensors is essential . It can be seen that the receiving , integrating of all data from various sensors can be a complex problem .With advances in sensor size , quality , and technology and continued developments in computer-control systems , artificial neural networks , sensor fusion has become practical and available at low cost .Movement is relatively independent of the number of components, the equivalent of our body, waist is a rotary degree of freedom We have to be able to hold his arm, Arm can be bent, then this three degrees of freedom, Meanwhile there is a wrist posture adjustment to the use of the three autonomy, the general robot has six degrees of freedom. We will be able to space the three locations, three postures, the robot fully achieved, and of course we have less than six degrees of freedomFiber-optic sensors are being developed for gas-turbine engines . These sensors will be installed in critical locations and will monitor the conditions inside the engine , such as temperature , pressure , and flow of gas . Continuous monitoring of the signals from thes sensors will help detect possible engine problems and also provide the necessary data for improving the efficiency of the engines .传感器技术传感器一种通过检测某一参数而产生信号的装置。
电容式传感器
电容式传感器电容式传感器是以各种类型的电容器作为传感元件,将被测物理量或机械量转换成为电容量变化的一种转换装置,实际上就是一个具有可变参数的电容器。
电容式传感器广泛用于位移、角度、振动、速度、压力、成分分析、介质特性等方面的测量。
最常用的是平行板型电容器或圆筒型电容器。
[1]中文名;电容式传感器;外文名capacitive type transducer电容计算公式:εS/d应用:测量简介70年代末以来,随着集成电路技术的发展,出现了与微型测量仪表封装在一起的电容式传感器。
这种新型的传感器能使分布电容的影响大为减小,使其固有的缺点得到克服。
电容式传感器是一种用途极广,很有发展潜力的传感器。
典型的电容式传感器由上下电极、绝缘体和衬底构成。
当薄膜受压力作用时,薄膜会发生一定的变形,因此,上下电极之间的距离发生一定的变化,从而使电容发生变化。
但电容式压力传感器的电容与上下电极之间的距离的关系是非线性关系,因此,要用具有补偿功能的测量电路对输出电容进行非线性补偿。
原理电容式传感器也常常被人们称为电容式物位计,电容式物位计的电容检测元件是根据圆筒形电容器原理进行工作的,电容器由两个绝缘的同轴圆柱极板内电极和外电极组成,在两筒之间充以介电常数为ε的电解质时,两圆筒间的电容量为式中L为两筒相互重合部分的长度;D为外筒电极的直径;d为内筒电极的直径;e为中间介质的电介常数。
在实际测量中D、d、e是基本不变的,故测得C即可知道液位的高低,这也是电容式传感器具有使用方便,结构简单和灵敏度高,价格便宜等特点的原因之一。
电容式传感器是以各种类型的电容器作为传感元件,由于被测量变化将导致电容器电容量变化,通过测量电路,可把电容量的变化转换为电信号输出。
测知电信号的大小,可判断被测量的大小。
这就是电容式传感器的基本工作原理。
[2]分类根据传感器的工作原理可把电容式传感器分为变极距型、变面积型和变介质型三种类型。
根据传感器的结构可把电容式传感器分为三种类型的结构形式。
传感器的基础知识论文中英文资料对照外文翻译
传感器的根底知识论文中英文资料对照外文翻译英文文献翻译中英文资料对照外文翻译Basic knowledge of transducersA transducer is a device which converts the quantity being measured into an optical, mechanical, or-more commonly-electrical signal. Theenergy-conversion process that takes place is referred to as transduction.Transducers are classified according to the transduction principle involved and the form of the measured. Thus a resistance transducer for measuring displacement is classified as a resistance displacement transducer. Other classification examples are pressure bellows, force diaphragm, pressure flapper-nozzle, and so on. 1、Transducer Elements Although there are exception ,most transducers consist of a sensing element and a conversion or control element. For example, diaphragms,bellows,strain tubes and rings, bourdon tubes, and cantilevers are sensing elements which respond to changes in pressure or force and convert these physical quantities into a displacement. This displacement may then be used to change an electrical parameter such as voltage, resistance, capacitance, or inductance. Such combination of mechanical and electrical elements form electromechanical transducing devices or transducers. Similar combination can be made for other energy input such as thermal. Photo, magnetic and chemical,giving thermoelectric, photoelectric,electromaanetic, and electrochemical transducers respectively. 2、Transducer SensitivityThe relationship between the measured and the transducer output signal is usually obtained by calibration tests and is referred to as the transducer sensitivity K1= output-signal increment / measured increment .In practice, the transducer sensitivity is usually known, and, by measuring the output signal, the input quantity is determined from input= output-signal increment / K1.3、Characteristics of an Ideal TransducerThe high transducer should exhibit the following characteristicsa) high fidelity-the transducer output waveform shape be a faithful reproduction of the measured; there should be minimum distortion.b) There should be minimum interference with the quantity being measured; the presence of the transducer should not alter the measured in any way.c) Size. The transducer must be capable of being placed exactly where it is needed.1英文文献翻译d) There should be a linear relationship between the measured and the transducer signal. e) The transducer should have minimum sensitivity to external effects, pressuretransducers,for example,are often subjected to external effects such vibration and temperature. f) The natural frequency of the transducer should be well separated from the frequency and harmonics of the measurand.4、Electrical TransducersElectrical transducers exhibit many of the ideal characteristics. In addition they offer high sensitivity as well as promoting the possible of remote indication or mesdurement. Electrical transducers can be divided into two distinct groups: a) variable-control-parameter types,which include: i)resistance ii) capacitance iii) inductanceiv) mutual-inductance typesThese transducers all rely on external excitation voltage for their operation. b) self-generating types,which include i) electromagnetic ii)thermoelectric iii)photoemissive iv)piezo-electric typesThese all themselves produce an output voltage in response to the measurand input and their effects are reversible. For example, a piezo-electric transducer normally produces an output voltage in response to the deformation of a crystalline material; however, if an alternating voltage is applied across the material, the transducer exhibits the reversible effect by deforming or vibrating at the frequency of the alternating voltage. 5、Resistance TransducersResistance transducers may be divided into two groups, as follows: i) Those which experience a large resistance change, measured by using potential-divider methods. Potentiometers are in this group.ii)Those which experience a small resistance change, measured by bridge-circuit methods. Examples of this group include strain gauges and resistance thermometers. 5.1 PotentiometersA linear wire-wound potentiometer consists of a number of turns resistance wire wound around a non-conducting former, together with a wiping contact which travels over the barwires. The construction principles are shown in figure which indicate that the wiper2英文文献翻译displacement can be rotary, translational, or a combination of both to give a helical-type motion. The excitation voltage may be either a.c. or d.c. and the output voltage is proportional to the input motion, provided the measuring device has a resistance which is much greater than the potentiometer resistance.Such potentiometers suffer from the linked problem of resolution and electrical noise. Resolution is defined as the smallest detectable change in input and is dependent on the cross-sectional area of the windings and the area of the sliding contact. The output voltage is thus a serials of steps as the contact moves from one wire to next.Electrical noise may be generated by variation in contact resistance, by mechanical wear due to contact friction, and by contact vibration transmitted from the sensing element. In addition, the motion being measured may experience significant mechanical loading by the inertia and friction of the moving parts of the potentiometer. The wear on the contacting surface limits the life of a potentiometer to a finite number of full strokes or rotations usually referred to in the manufacture’s specification as the ‘number of cycles of life expectancy’, a typical value being 20*1000000 cycles.The output voltage V0 of the unload potentiometer circuit is determined as follows. Let resistance R1= xi/xt *Rt where xi = input displacement, xt= maximum possible displacement, Rt total resistance of the potentiometer. Then output voltage V0= V*R1/(R1+( Rt-R1))=V*R1/Rt=V*xi/xt*Rt/Rt=V*xi/xt. This shows that there is a straight-line relationship between output voltage and input displacement for the unloaded potentiometer. It would seen that high sensitivity could be achieved simply by increasing the excitation voltage V. however, the maximum value of V is determined by the maximum power dissipation P of the fine wires of the potentiometer winding and is given by V=(PRt)1/2 . 5.2 Resistance Strain GaugesResistance strain gauges are transducers which exhibit a change in electrical resistance in response to mechanical strain. They may be of the bonded or unbonded variety . a) bonded strain gaugesUsing an adhesive, these gauges are bonded, or cemented, directly on to the surface of the body or structure which is being examined. Examples of bonded gauges arei) fine wire gauges cemented to paper backingii) photo-etched grids of conducting foil on an epoxy-resin backingiii)a single semiconductor filament mounted on an epoxy-resin backing with copper or nickel leads.Resistance gauges can be made up as single elements to measuring strain in one direction only,3英文文献翻译or a combination of elements such as rosettes will permit simultaneous measurements in more than one direction. b) unbonded strain gauges A typical unbonded-strain-gauge arrangement shows fine resistance wires stretched around supports in such a way that the deflection of the cantilever spring system changes the tension in the wires and thus alters the resistance of wire. Such an arrangement may be found in commercially available force, load, or pressure transducers. 5.3 Resistance Temperature TransducersThe materials for these can be divided into two main groups:a) metals such as platinum, copper, tungsten, and nickel which exhibit and increase in resistance as the temperature rises; they have a positive temperature coefficient of resistance. b) semiconductors, such as thermistors which use oxides of manganese, cobalt, chromium, or nickel. These exhibit large non-linear resistance changes with temperature variation and normally have a negative temperature coefficient of resistance. a) metal resistance temperature transducersThese depend, for many practical purpose and within a narrow temperature range, upon the relationship R1=R0*[1+a*(b1-b2)] where a coefficient of resistance in ℃-1,and R0 resistance in ohms at the reference temperature b0=0℃ at the reference temperature range ℃.℃℃. b) thermistor resistance temperature transducersThermistors are temperature-sensitive resistors which exhibit large non-liner resistance changes with temperature variation. In general, theyhave a negative temperature coefficient. For small temperature increments the variation in resistance is reasonably linear; but, if large temperature changes are experienced, special linearizing techniques are used in the measuring circuits to produce a linear relationship of resistance against temperature.Thermistors are normally made in the form of semiconductor discs enclosed in glass vitreous enamel. Since they can be made as small as 1mm,quite rapid response times are possible. 5.4 Photoconductive Cells The photoconductive cell , uses a light-sensitive semiconductor material. The resistance between the metal electrodes decrease as the intensity of the light striking the semiconductor increases. Common semiconductor materials used for photo-conductive cells are cadmium sulphide, lead sulphide, and copper-doped germanium.The useful range of frequencies is determined by material used. Cadmium sulphide is mainly suitable for visible light, whereas lead sulphide has its peak response in the infra-red region4英文文献翻译and is, therefore , most suitable for flame-failure detection and temperature measurement. 5.5 Photoemissive CellsWhen light strikes the cathode of the photoemissive cell are given sufficient energy to arrive the cathode. The positive anode attracts these electrons, producing a current which flows through resistor R and resulting in an output voltage V. Photoelectrically generated voltage V=Ip.RlWhere Ip=photoelectric current(A),and photoelectric current Ip=Kt.B Where Kt=sensitivity (A/im),and B=illumination input (lumen)Although the output voltage does give a good indication of the magnitude of illumination, the cells are more often used for counting or controlpurpose, where the light striking the cathode can be interrupted. 6、Capacitive TransducersThe capacitance can thus made to vary by changing either the relative permittivity, the effective area, or the distance separating the plates. The characteristic curves indicate that variations of area and relative permittivity give a linear relationship only over a small range of spacings. Thus the sensitivity is high for small values of d. Unlike the potentionmeter, the variable-distance capacitive transducer has an infinite resolution making it most suitable for measuring small increments of displacement or quantities which may be changed to producea displacement.7、Inductive TransducersThe inductance can thus be made to vary by changing the reluctance of the inductive circuit. Measuring techniques used with capacitive and inductive transducers: a)A.C. excited bridges using differential capacitors inductors. b)A.C. potentiometer circuits for dynamic measurements.c) D.C. circuits to give a voltage proportional to velocity for a capacitor.d) Frequency-modulation methods, where the change of C or L varies the frequency of an oscillation circuit.Important features of capacitive and inductive transducers are as follows: i)resolution infiniteii) accuracy+- 0.1% of full scale is quoted iii)displacement ranges 25*10-6 m to 10-3m iv) rise time less than 50us possibleTypical measurands are displacement, pressure, vibration, sound, and liquid level. 8、 Linear Variable-differential Ttransformer 9、Piezo-electric Transducers5。
最新传感器技术外文文献及中文翻译资料
Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque , pressure , temperature , humidity , speed , acceleration , or vibration .Traditionally ,sensors (such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a) stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features , and (c) governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems .It is essential for proper data acquisition and for the monitoring , communication , and computer control of machines and systems .Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly .Analog-to-coverter(ADC) is available for interfacing analog sensors with computers .Classifications of SensorsSensors that are of interest in manufacturing may be classified generally as follows:Machanical sensors measure such as quantities aspositions ,shape ,velocity ,force ,torque , pressure , vibration , strain , and mass .Electrical sensors measure voltage , current , charge , and conductivity .Magnetic sensors measure magnetic field ,flux , and permeablity .Thermal sensors measure temperature , flux ,conductivity , and special heat .Other types are acoustic , ultrasonic , chemical , optical , radiation , laser ,and fiber-optic .Depending on its application , a sensor may consist of metallic , nonmetallic , organic , or inorganic materials , as well as fluids ,gases ,plasmas , or semiconductors .Using the special characteristics of these materials , sensors covert the quantity or property measured to analog or digital output. The operation of an ordinary mercury thermometer , for example , is based on the difference between the thermal expansion of mercury and that of glass.Similarly , a machine part , a physical obstruction , or barrier in a space can be detected by breaking the beam of light when sensed by a photoelectric cell . A proximity sensor ( which senses and measures the distance between it and an object or a moving member of a machine ) can be based on acoustics , magnetism , capacitance , or optics . Other actuators contact the object and take appropriate action ( usually by electromechanical means ) . Sensors are essential to the conduct of intelligent robots , and are being developed with capabilities that resemble those of humans ( smart sensors , see the following ).This is America, the development of such a surgery Lin Bai an example, through the screen, through a remote control operator to control another manipulator, through the realization of the right abdominal surgery A few years ago our country theexhibition, the United States has been successful in achieving the right to the heart valve surgery and bypass surgery. This robot has in the area, caused a great sensation, but also, AESOP's surgical robot, In fact, it through some equipment to some of the lesions inspections, through a manipulator can be achieved on some parts of the operation Also including remotely operated manipulator, and many doctors are able to participate in the robot under surgery Robot doctor to include doctors with pliers, tweezers or a knife to replace the nurses, while lighting automatically to the doctor's movements linked, the doctor hands off, lighting went off, This is very good, a doctor's assistant.Tactile sensing is the continuous of variable contact forces , commonly by an array of sensors . Such a system is capable of performing within an arbitrarythree-dimensional space .has gradually shifted from manufacturing tonon-manufacturing and service industries, we are talking about the car manufacturer belonging to the manufacturing industry, However, the services sector including cleaning, refueling, rescue, rescue, relief, etc. These belong to the non-manufacturing industries and service industries, so here is compared with the industrial robot, it is a very important difference. It is primarily a mobile platform, it can move to sports, there are some arms operate, also installed some as a force sensor and visual sensors, ultrasonic ranging sensors, etc. It’s surrounding environment for the conduct of identification, to determine its campaign to complete some work, this is service robot’s one of the basic characteristicsIn visual sensing (machine vision , computer vision ) , cameral optically sense the presence and shape of the object . A microprocessor then processes the image ( usually in less than one second ) , the image is measured , and the measurements are digitized ( image recognition ) .Machine vision is suitable particularly for inaccessible parts , in hostile manufacturing environments , for measuring a large number of small features , and in situations where physics contact with the part may cause damage .Small sensors have the capability to perform a logic function , to conducttwo-way communication , and to make a decisions and take appropriate actions . The necessary input and the knowledge required to make a decision can be built into a smart sensor . For example , a computer chip with sensors can be programmed to turn a machine tool off when a cutting tool fails . Likewise , a smart sensor can stop a mobile robot or a robot arm from accidentally coming in contact with an object or people by using quantities such as distance , heat , and noise .Sensor fusion . Sensor fusion basically involves the integration of multiple sensors in such a manner where the individual data from each of the sensors ( such as force , vibration , temperature , and dimensions ) are combined to provide a higher level of information and reliability . A common application of sensor fusion occurs when someone drinks a cup of hot coffee . Although we take such a quotidian event for granted ,it readily can be seen that this process involves data input from the person's eyes , lips , tongue , and hands .Through our basic senses of sight , hearing , smell , taste , and touch , there is real-time monitoring of relative movements , positions , and temperatures . Thus if the coffee is too hot , the hand movement of the cup toward the lip is controlled and adjusted accordingly .The earliest applications of sensor fusion were in robot movement control , missile flight tracking , and similar military applications . Primarily because these activities involve movements that mimic human behavior . Another example of sensor fusion is a machine operation in which a set of different but integrated sensors monitors (a) the dimensions and surface finish of workpiece , (b) tool forces , vibrations ,and wear ,(c) the temperature in various regions of the tool-workpiece system , and (d) the spindle power .An important aspect in sensor fusion is sensor validation : the failure of one particular sensor is detected so that the control system maintains high reliability . For this application ,the receiving of redundant data from different sensors is essential . It can be seen that the receiving , integrating of all data from various sensors can be a complex problem .With advances in sensor size , quality , and technology and continued developments in computer-control systems , artificial neural networks , sensor fusion has become practical and available at low cost .Movement is relatively independent of the number of components, the equivalent of our body, waist is a rotary degree of freedom We have to be able to hold his arm, Arm can be bent, then this three degrees of freedom, Meanwhile there is a wrist posture adjustment to the use of the three autonomy, the general robot has six degrees of freedom. We will be able to space the three locations, three postures, the robot fully achieved, and of course we have less than six degrees of freedomFiber-optic sensors are being developed for gas-turbine engines . These sensors will be installed in critical locations and will monitor the conditions inside the engine , such as temperature , pressure , and flow of gas . Continuous monitoring of the signals from thes sensors will help detect possible engine problems and also provide the necessary data for improving the efficiency of the engines .传感器技术传感器一种通过检测某一参数而产生信号的装置。
电气工程与自动化外文翻译外文文献英文文献一种低成本智能式电容位置传感器
文献、资料题目: A Low-Cost, Smart Capacitive Position Sensor 文献、资料来源:IEEE TRANSACTIONS ON INSTRUMENT AND MEASUREMENT 文献、资料发表(出版)日期:1992.12 院(部):信息与电气工程学院__________________________________________专业:电气工程与自动化___________________________外文文献:A Low-Cost, Smart Capacitive Positi on Sen sorAbstractA new high-performanee, low-cost, capacitive position-measuring system is described. By using a highly linear oscillator, shielding and a three-signal approach, most of the errors are eliminated. The accuracy amounts to 1 卩m over a 1 mmcanig e .oStiput of the oscillatorcan directly be conn ected to a microc on troller, an A/D conv erter is not n eeded.I. INTRODUCTIONThis paper describes a no vel high-performa nee, low-cost, capacitive displaceme nt measuri ng system featuri ng:1 mm measuri ng ran ge,1 卩m accuracy,0.1 s total measuri ng time.Tran slated to the capacitive doma in, the specificati ons corresp ond to:a possible range of 1 pF;only 50 fF of this range is used for the displaceme nt tran sducer;50 aF absolute capacita nce-measuri ng in accuracy.Meijer and Schrier [l] and more rece ntly Van Drecht,Meijer, and De Jong [2] have proposed a displaceme nt-measuri ng system,us ing a PSD (Positi on Sen sitive Detector) as sensing eleme nt. Some disadva ntages of using a PSD are the higher costs and the higher power con sumpti on of the PSD and LED (Light-Emitting Diode) as compared to the capacitive sensor elements described in this paper.The sig nal processor uses the con cepts prese nted in [2],but is adopted for the use of capacitive elements. By the extensive use of shielding, guarding and smart A/D conversion,the system is able to combine a high accuracy with a very low cost-price. The transducer produces three-period-modulated sig nals which can be selected and directly read out by a microc on troller. The microcontroller,in return, calculates the displacement and can send this value to a host computer (Fig. 1) or a display or drive an actuator.Fig. 1. Block diagram of the systemII . THE ELECTRODE STRUCTUREThe basic sensing element consists of two simple electrodes with capacitance Cx, (Fig. 2). The smaller one (E2) is surro un ded by a guard electrode. Thanks to the use of the guard electrode, the capacita nce Cx betwee n the two electrodes is in depe ndent of moveme nts (lateral displaceme nts as well as rotati ons) parallel to the electrode surface.The in flue nce of the parasitic capacita nces Cp will be eliminated as will be discussed in Section M .According to Heerens [3], the relative deviation in the capacitance Cx between the two electrodes caused by the finite guard electrode size is smaller than:S<€冗(x/d)(1)where x is the width of the guard and d the distance between the electrodes. This deviationElectro nic CircuitHPCrefPers onal ComputerCsFI I 1 I 一 1Sli i&l rlir.f?Fig. 2. Perspective and dime nsions of the electrode structureintroduces a nonlinearity.Therefore we require that S is less than 100 ppm.Also the gap between the small electrode and the surro unding guard causes a deviati on:S <n (d/s)(2)with s the width of the gap. This deviati on is n egligible compared to (l), whe n the gap width is less than 1/3 of the distance between the electrodes.Another cause of errors originates from a possible finite skew angle a between the two electrodes (Fig. 3). Assu ming the follow ing con diti ons:the pote ntials on the small electrode and the guard electrode are equal to 0 V, the pote ntial on the large electrode is equal to V volt, the guard electrode is large eno ugh,it can be seen that the electric field will be concentric.To keep the calculations simple, we will assume the electrodes to be infinitely large in one direct ion. Now the problem is a two-dime nsio nal one that can be solved by using © ). In this case the electrical field can be described by:V sinV cos rTo calculate the charge on the small electrode, we set and in tegrat 命otveO r:with Bl the left border of the small electrode:polar-coordi nates (r,B^drB IFig. 3. Electrodes with angle . aQ V」ln 2d COS丨亦a 2d cos l sinFor small a's this can be approximated by:C 卫 1 4^ 2d 12dIt appears to be desirable to choose l smaller tha n d, so the error will depe nd only on the an glea .In our case, a change in the angle of 0.6 ° will cause an error less than 100 ppm.With a proper design the parameters £ o and l are constant,and then the capacitanee between thtwo electrodes will depe nd only on the dista nee d betwee n the electrodes.川.ELIMINATION OF PARASITIC CAPACITANCESBesides the desired sen sor capacita nee C, there are also many parasitic capacita nces in theactual structure (Fig.2). These capacitances can be modeled as shown in Fig.4. Here Cpl represe nts the parasitic capacita nces from the electrode E1 and Cp2 from the electrode E2 to the guard electrodes and the shield ing. Parasitic capacita nee Cp3 results from imperfect shield ing and forms an offset capacita nee. Whe n the tran sducer capacita nee Cx is conn ected to an AC voltage source and the current through the electrode is measured,Cpl and Cp2 will be eliminated. Cp3 can be elimi nated by perform ing an offset measureme nt.and Br the right border:Solvi ng (4) results in:B iB rdtandtan(8)Fig. 4. Elimination of parasitic capacitancesThe current is measuredby the amplifier with shunt feedback, which has a very low input impedanee. To obtain the required linearity, the unity-gain bandwidth fT of the amplifier has to satisfy the following condition:where T is the period of the in put sig nal.Since Cp2 con sists of cable capacita nces and the in put capacita nee of the op amp, it may in deed be larger tha n Cf and can not be n eglected.IV. THE CONCEPT OF THE SYSTEMThe system uses the three-sig nal con cept prese nted in [2], which is based on the follow ing principles. When we measure a capacitor Cx with a linear system, we obtain a value:Here, P is a value representing the position while a1 and aO are unknown, but stable constants.12 C f (9)C fCp2mC xMoff(10)where m is the unknown gain and Moff, the unknown offset.By perform ing the measureme nt of a refere nee qua ntity Cref, i n an ide ntical way and by measuri ng the offset, Moff,by maki ng m = 0, the parameters m and Moff are eliminated.The final measurement result P is defined as:MrefMoffM x M O ff(11)In our case, for the sen sor capacita nee C, it holds that:A x d o d(12)where Ax is the area of the electrode, do is the initial distance between them,con sta nt and A d is the displaceme nt to be measured. For the refere nce electrodes it holds that:A refC ref丁-(13)£ iswith Aref the area and dref the distance. Substitution of (12) and (13) into (10) and then into (11) yields:A ref d o dA x d refd a 1 — aodrefThe constant al =Aref/Ax is a stable constant provided there is a good mechanical matching betwee n the electrode areas.The con sta nt ao = (ArefdO/(Axdref) will also be a stable con sta nt provided that do and dref are constant. These constants can be determined by a one-time calibration. In many applications this calibration can be omitted; when the displacement sensor is part of a larger system, an overall calibrati on is required any way. This overall calibrati on elim in ates the requireme nt for a separate determ in atio n of a1 and a0.V . THE CAPACITANCE-TO-PERIOD CONVERSIONThe sig nals which are proporti onal to the capacitor values are con verted into a period, using a modified Martin oscillator [4] (Fig. 5j.When the voltage swing across the capacitor is equal to that across the resistor and the NAND gates are switched off, this oscillator has a period Toff:Toff = 4RCoff. (15) Since the value of the resistor is kept constant, the period varies only with the capacitor value. Now, by switching on the right NAND port, the capacitance CX can be connected in parallel to Coff. Then the period becomes:Tx=4R(Coff+Cx)=4RCx+Toff (16) The constants R and Toff are eliminated in the way described in Section IV.In [2] it is shown that the system is immune for most of the nonidealities of the op amp and the comparator, like slew ing, limitati ons of ban dwidth and gain, offset voltages,a nd in put bias curre nts. These noni dealities only cause additive or multiplicative errors which are elimi nated by the three-sig nal approach.VI. PERIOD MEASUREMENT WITH A MICROCONTROLLERPerformi ng period measureme nt with a microc on troller is an easy task. In our case, an INTEL 87C51FA is used,which has 8 kByte ROM, 256 Byte RAM, and UART for serial communication, and the capability to measure periods with a 333 ns resolution. Even though the counters are 16 b wide, they can easily be exte nded in the software to 24 b or more.The period measureme nt takes place mostly in the hardware of the microc on troller. Therefore, it is possible to let the CPU of the microc on troller perform other tasks at the same time (Fig. 6). For in sta nce, simulta neously with the measureme nt of period Tx, period Tref and period Toff,the relative capacitance with respect to Cref is calculated according to (11), and the result istran sferred through the UART to a pers onal computer.Fig. 5. Modified Martin oscillator with microcontroller and electrodes.Fig. 6. Period measureme nt as backgro und process.Fig. 7. Position error as function of the position and estimate of the nonlinearity.VII. EXPERIMENTAL RESULTSThe sensor is not sensitive to fabrication tolerances of the electrodes. Therefore in ourexperime ntal setup we used simple prin ted circuit board tech no logy to fabricate the electrodes, which have an effective area of 12 mm 12 mm.The guard electrode has a width of 15 mm, while the distance between the electrodes is about 5 mm. When the distance between the electrodes is varied over a 1 mm range, the capacitance changes from 0.25 pF to 0.3 pF.Thanks to the chosen concept, even a simple dual op amp (TLC272AC) and CMOS NAND ' s could be used allowing a single 5 V supply voltage. The total measurement time amounts to only 100 ms, where the oscillator was running at about 10 kHz.The system was tested in a fully automated setup, using an electrical XY table, the described sen sor and a pers onal computer. To achieve the required measureme ntaccuracy the setup was autozeroed every minute. In this way the nonlinearity, Iong-term stability and repeatability have been found to better than 1 卩m over a range of 1 mm (Fig.7). This is comparable to the accuracy and range of the system based on a PSD as described in [2].As a result of these experime nts, it was found that the resoluti on amounts to approximately 20 aF. This result was achieved by averag ing over 256 oscillator periods. A further in crease of the resolution by lengthening the measurement time is not possible due to the l/f noise produced by the first stages in both the integrator and the Comparator.The absolute accuracy can be derived from the positi on accuracy. Since a 1 mm displaceme nt corresponds to a change in capacitance of 50 fF, the absolute accuracy of 1 卩m in the amounts to an absolute accuracy of 50 aF.CONCLUSIONA low-cost, high-performance displacement sensor has been presented. The system is implemented with simple electrodes, an inexpensive microcontroller and a linearcapacitance-to-period converter. When the circuitry is provided with an accurate reference capacitor, the circuit can also be used to replace expe nsive capacity-measuri ng systems.REFERENCES[1]G. C. M. Meijer and R. Sch ner, “ A -ip e rio hrigince PSDdisplacement transducer with a microcontroller interfacing, ” Sensorsand Actuators, A21-A23, pp. 538-543, 1990.[2]J. van Drecht, G. C. M. Meijer, and P. C. de Jong, for'tBo nceptsdesig n of smart sen sors and smart sig nal processors and their applicatio nto PSD displaceme nt tran sducers. Digesr of Tech ni cal Papers, Transducers ' 91.[3]W. C. Heere ns. “ Applicati on of capacita nee tech niq ues in sen sor desig n, Phys. E: Sci. I nsfrum., vol. 19, pp. 897-906, 1986.[4]K. Marti n, '‘ A-c o lnageled switched-capacitor relaxation oscillator,IEEEJ., vol. SC-16, pp. 412-413, 1981.中文译文:一种低成本智能式电容位置传感器摘要本文描述了一种新的高性能,低成本电容位置测量系统。
传感器温湿度测量中英文资料外文翻译文献
中英文资料外文翻译文献SHT11/71传感器的温湿度测量Assist.Prof.Grish Spasov,PhD,BSc Nikolay KakanakovDepartment of Computer Systems,Technical University-branch Plovdiv,25,”Tzanko Djustabanov”Str.,4000Plovdiv,Bulgaria,+35932659576, E-mail:gvs@tu-plovdiv.bg,kakanak@tu-plovdiv.bg 关键词:温湿度测量,智能传感器,分布式自动测控这篇论文阐述了智能传感器的优点,介绍了SHT11/71温湿度传感器(产自盛世瑞公司)。
该传感器是一种理想的对嵌入式系统提供环境测量参数的传感器。
常规的应用时将SHT11/71放于实际的工作环境当中。
应用于分布式的温湿度监测系统。
使用单片机与集成网络服务器来实现对传感器的信息交流与关系。
这个应用是可实现与测试的。
1.介绍温湿度的测量控制对于电器在工业、科学、医疗保健、农业和工艺控制过程都有着显著地意义。
温湿度这两种环境参数互相影响,因为这至关重要的一点,在一些应用中他们是必须并联测量的。
SHT11/71是利用现代技术把温度、湿度测量元件、放大器、A/D转换器、数字接口、校验CRC计算逻辑记忆模块和核心芯片集成到一个非常小的尺寸上[1][3]。
采用这种智能传感器可以缩短产品开发时间和成本。
整合入传感器模数转换和放大器的芯片使开发人员能够优化传感器精度和长期问的的元素。
并不是全结合形式的数字逻辑接口连通性管理的传感器。
这些优点可以减少整体上市时间,甚至价格[1][3]。
本文以SHT11/71(产自盛世瑞公司)智能传感器为例,介绍他的优势和测量程序给出一个实用实例来说明该工作的实现条件。
这个应用时可行可测试的。
2.智能传感器——SHT11/71SHT11/71是一个继承了温度和湿度组建,以及一个多元化校准数字器的芯片。
电容式传感器的外文文献翻译、中英文翻译、外文翻译
参考资料原文:Capacitive sensors and the main features of the basic concepts: The measured volume of the machinery, such as displacement, pressure change is converted to the sensor capacitance. It is the sensitive part of the capacitor with variable parameters. Its most common form is composed of two parallel electrodes, a very inter-air as the medium of the capacitor, if the neglect edge effects, the capacitance for the capacitor plate ε A / δ, where εis a very inter-medium dielectric constant, A two electrode effective area covered by each other, δ is the distance between two electrodes. δ, A, εone of the three parameters will lead to the change in capacitance changes can be used for measurement. Therefore capacitive sensors can be divided into polar distance change type, change type size, media type three types of changes.Most from the changes in small type generally used to measure the linear displacement, or as a result of force, pressure, vibration caused by changes in polar distance (see capacitive pressure sensors). Change type size generally used to measure the angular displacement or linear displacement larger. Changes in media type commonly used in level measurement and a variety of media, temperature, density, humidity measurement. The advantage of the sensor capacitor structure is simple, inexpensive, high sensitivity,过载能力strong, good dynamic response and high temperature, radiation, vibration and other adverse conditions of strong adaptability and strong. The disadvantage is that there are non-linear output, parasitic capacitance and the distributed capacitance on the sensitivity and accuracy the impact of larger and more complex circuits, such as connectivity. Since the late 70s, with the development of integrated circuit technology, a packaging and micro-measuring instrument with capacitive sensors.This new type of distributed capacitance sensors can greatly reduce the impact to overcome the inherent drawbacks. Capacitive sensor is a very wide use, a great potential for development of the sensor.Capacitive sensor working principle:Capacitive sensor surface of the induction of two coaxial metal electrode composition, much like "open" capacitor electrode, the two electrodes form a capacitor, in series with the RC oscillation circuit. Power when connected, RC oscillator is notoscillating, when a goal of moving around electrical capacitor, the capacitor capacity increased, the oscillator to start oscillation. Circuit after the passage of the deal, will be two kinds of vibration and vibration signals into switching signals, which played a detection purpose of the existence of any objects. The sensor can detect metal objects, but also to detect non-metallic objects, metal objects can move away from the largest, non-metallic objects on the decision to move away from the dielectric constant material, the greater the dielectric constant materials, the availability of action the greater distance.Application of capacitive sensors:Capacitive sensor can be used to measure linear displacement, angular displacement, vibration amplitude, especially suitable for measuring high-frequency vibration amplitude, precision rotary axis accuracy, acceleration and other mechanical parameters. Pole-changing type of application from a smaller displacement in the measurement range to several hundred microns in 0.01m, precision can reach 0.01m, a resolution of up to 0.001m. Change type size larger displacement can be measured, for the zero-range a few millimeters to a few hundred mm, 0.5 percent better than the linear resolution of 0.01 ~ 0.001m. Capacitive angular displacement sensor point of view and the dynamic range to a few degrees, a resolution of about 0.1 "up to the stability of the zero angle-second, widely used in precision angle measurement, such as for high-precision gyroscopes and accelerometers tilting . capacitive measurement sensor can measure the peak amplitude for the 0 ~ 50m, a frequency of 10 ~ 2kHz, sensitivity is higher than 0.01m, non-linear error of less than 0.05m.Capacitive sensor can also be used to measure pressure, differential pressure, level, surface, composition content (such as oil, the water content of food), non-metallic coating materials, such as film thickness, dielectric measurements of humidity, density, thickness, etc., in the automatic detection and control systems are also often used as a location signal generator. Capacitive differential pressure sensor measuring range up to 50MPa, an accuracy of ± 0.25% ~ ± 0.5%. Capacitive sensor for measuring range of the thickness of a few hundred microns, resolution of up to 0.01m. Capacitive Proximity Switches can not only detect metal, but also can detect plastic, wood,paper, and other dielectric liquids, but can not achieve the ultra-small, the movement distance of about 10 ~ 20mm. Electrostatic capacitive level switch is widely used in detection is stored in the tank, hopper, such as the location of containers in a variety of objects of a mature product. When the capacitive sensor measuring metal surface conditions, from the size, vibration amplitude is often used very variable from unilateral type, when the measured object is a capacitor electrode, and the other electrode in the sensor inside. This type of sensor is a non-contact measurement, dynamic range is relatively small, about a few millimeters is about the precision of more than 0.1m, a resolution of 0.01 ~ 0.001m.译文:电容式传感器的基本概念及主要特点:把被测的机械量,如位移、压力等转换为电容量变化的传感器。
传感器技术外文文献及中文翻译
传感器技术外文文献及中文翻译引言传感器是现代检测技术的重要组成部分,它能将物理量、化学量等非电信号转换为电信号,从而实现检测和控制。
传感器广泛应用于工业、医疗、军事等领域中,如温度、湿度、气压、光强度等参数检测。
随着科技的发展,传感器不断新型化、微型化和智能化,已经涵盖了人体所有的感官,开启了大规模的物联网与智能化时代。
本文将介绍几篇与传感器技术相关的外文文献,并对其中较为重要的内容进行中文翻译。
外文文献1标题“Flexible Sensors for Wearable Health: Why Materials Matter”作者Sarah O’Brien, Michal P. Mielczarek, and Fergal J. O’Brien文献概述本文主要介绍了柔性传感器在可穿戴健康监测中的应用,以及传感材料的选择对柔性传感器性能的影响。
文章先介绍了柔性传感器的基本工作原理和常见的柔性传感材料,然后重点探讨了传感材料对柔性传感器灵敏度、稳定性、响应速度等性能的影响。
最后,文章提出未来柔性传感器材料需满足的性能要求,并对可能的研究方向和应用进行了展望。
翻译摘要柔性传感器是可穿戴健康监测中重要的成分,通过将身体状态转化为电信号进行检测。
选择合适的传感材料对柔性传感器产品的成本、性能及标准化有着面向未来的影响。
本文对柔性材料的常见种类 (如: 聚合物、金属、碳复合材料等) 进行了介绍,并重点探讨了传感材料选择的影响因素,如对柔性传感器的灵敏度、特异性和响应时间等。
此外,文章还探讨了柔性传感器的性能要求和建议未来的技术方向。
外文文献2标题“Smart sensing system for precision agriculture”作者Olivier Strauss, Lucas van der Meer, and Benoit Figliuzzi文献概述本文主要介绍智能传感系统在精准农业中的应用。
08湿度传感器系统毕业论文中英文资料外文翻译文献
湿度传感器系统中英文资料外文翻译文献英文:The right design for a relative humidity sensor systemOptimizing the response characteristics and accuracy of a humidity sensor system1 OverviewTo make the right choice when selecting a relative humidity sensor for an application, it is important to know and to be able to judge the deciding factors. In addition to long-term stability, which is a measure on how much a sensor changes its properties over time, these factors also include the measurement accuracy and the response characteristics of the sensor. Capacitive humidity sensors are based on the principle that a humidity-sensitive polymer absorbs or releases moisture as a function of the relative ambient humidity. Because this method is only a spot measurement at the sensor location, and usually the humidity of the surroundings is the desired quantity, the sensor must be brought into moisture equilibrium with the surroundings to obtain a precise measurement value. This process is realized by various transport phenomena (cf. the section titled "The housing effect on the response time"), which exhibit a time constant. Accuracy and response time are thus closely dependent on each other, and the design of a humidity measurement system becomes a challenge.2Measurement accuracyThe term measurement accuracy of a humidity sensor is understood primarily to refer to the deviation of the value measured by the sensor from the actual humidity. To determine the measurement accuracy, references, such as chilled mirror hygrometers, whose own tolerance must be taken into account, are used. In addition to this trivial component, humidity sensors require a given time for reaching stable humidity and temperature equilibrium (the humidity is a function of temperature and decreases with increasing temperature; a difference between sensor and ambient temperature leads to measurement errors). This response time thus has a significant effect on the value measured by the sensor and thus on the determined accuracy.This time-dependent characteristic is explained in more detail in the following.3Response characteristics and response timeThe response characteristics are defined by various parameters. These are:●The actual response characteristics of the humidity sensor at constant temperature.(1) How quickly the sensitive polymer absorbs or releases moisture until equilibrium is reached (intrinsic response time)(2) How fast the entire system reaches humidity equilibrium (housing effect)●The thermal response characteristics of the humidity sensor at a non-constant temperature(3) The thermal mass of the sensor(4) The system's thermal mass, which is thermally coupled to the sensor (e.g. printed circuit board)(5) Heat sources in the direct surroundings of the sensor (electronic components)(1) and (3) are determined entirely by the sensor itself, (1) primarily by the characteristics of the sensitive polymer.(2) and (4) are primarily determined by the construction of the entire system (shape and size of housing andreadout circuitry).(5) is determined by heat-emitting electronic components.These points will be discussed in more detail in the following.The intrinsic response time (1)Qualitatively, the response characteristics of capacitive humidity sensors look like the following (Fig. 1).Fig. 1: Typical and idealized response characteristics of capacitive humidity sensors (schematic)Because these response characteristics are especially pronounced at high humidity values,an isothermal humidity jump from 40% to 100% was selected here for illustration. The desired ideal behavior of the sensor is indicated in blue. In practice, however, the sensor behaves according to the red line, approximately according to:=(E-S)*(1-e)+SRH-t(t)Here, the time span 1 is usually very short (typ. 1 – 30 min.), in contrast, the time span 2 is very long (typ. Many hours to days). Here the connection of measurement accuracy and response characteristics becomes clear (t until RH=100% is reached). The value at t4 (Fig. 1) is considered to be an exact measured value. However, this assumes that both the humidity and also the temperature remain stable during this entire time, and that the testing waits until this very long measurement time is completed. These conditions are both very hard to achieve and unusual in practice. For the calibration, there are the following two approaches, which both find use in practice (cf. Fig. 2):1.The measured value at t2 (Fig. 1) is used as a calibration reference.Advantage:●The required measurement time for reaching the end value (in the example 100%) isclearly shortened,corresponds to practice, and achieves an apparent short responsetime of the sensor (cf. Fig. 2).Disadvantage:●If the conditions are similar for a long time (e.g., wet periods in outdoor operation),the sensors exceed the correct end value (in the example 100%) undesirably by upto 10% (cf. Fig. 2).2. The measured value at t4 (Fig. 1) is used as a calibration reference.Advantage:●Even for similar conditions over a long time (e.g., wet periods in outdoor operation),an exact measurement result is obtained (cf. Fig. 2).Disadvantage:●For a humidity jump like in Fig. 1, the sensors very quickly deliver the measuredvalue at t2, but reaching a stable end value (about 3-6% higher) takes a long time(apparent longer response time)(cf. Fig. 2).In order to take into account both approaches optimally, the measured values at t3 (cf. Fig. 1) are used as the calibration reference by Sensirion AG.Fig. 2: Response characteristics of different humidity measurement systemsThe housing effect on the response time (2)Here, two types of transport phenomena play a deciding role:●Convection: For this very fast process, the air, whose humidity is to be determined,is transported to the sensor by means of ventilation.●Diffusion: This very slow process is determined by the thermal, molecularself-motion of the water molecules. It occurs even in "stationary" air (e.g., within ahousing), but leads to a long response time.In order to achieve favorable response characteristics in the humidity measurement system, the very fast convection process must be supported by large housing openings and the slow diffusion process must be supported by a small housing around the sensor (small "deadvolume") with "stationary" air reduced to a minimum. The following applies:Thermal effects (3), (4), and (5)Because the total thermal mass of the humidity measurement system (sensor + housing)has a significant effect on its response time, the total thermal mass must be kept as low aspossible. The greater the total thermal mass, the more inert the measurement system becomesthermally and its response time, which is temperature-dependent, increases. In order toprevent measurement errors, the sensor should not be mounted in the vicinity of heatgenerating components.4Summary –what should be taken into account when designing a humidity measurement systemIn order to achieve error-free operation of a humidity-measurement system with response times as short as possible, the following points should be taken into account especially for the selection of the sensor and for the design of the system.●The selection of the humidity sensor element. It should●be as small as possible,●have a thermal mass that is as low as possible,●work with a polymer, which exhibits minimal fluctuations in measured values duringthe time span 2(cf. Fig. 1); testing gives simple information on this condition,●provide calibration, which corresponds to the requirements (see above), e. g.,SHT11/SHT15 from Sensirion.●The housing design (cf. Formula 1). It should●have air openings that are as large as possible in the vicinity of the sensor or thesensor should be operated outside of the housing à good convection!●enclose a "dead volume" that is as small as possible around the sensor àlittlediffusion!●The sensor should be decoupled thermally as much as possible from other components,so that the response characteristics of the sensor are not negatively affected by the thermal inertia of the entire system.(e.g., its own printed circuit board for the humidity sensor, structurally partitioning the housing to create a small volume for the humidity sensor, see Fig. 3)Fig. 3: Mounting example for Sensirion sensors SHT11 and SHT15 with slits for thermal decoupling●The sensor should not be mounted in the vicinity of heat sources. If it was, measuredtemperature would increase and measured humidity decrease.5Design proposalThe challenge is to realize a system that operates cleanly by optimally taking into account all of the points in section 4. The already calibrated SMD humidity sensors SHT11 and SHT15 from Sensirion are the ideal solution. For optimum integration of the sensors in a measurement system, Sensirion AG has also developed a filter cap as an adapter aid, which takes into account as much as possible the points in section 4 and also protects the sensor against contaminants with a filter membrane. Fig. 4 shows schematically how the sensors can be ideally integrated into a housing wall by means of the filter cap SF1.Fig. 4: Filter cap for SHT11 and SHT15In addition to the advantages mentioned above, there is also the option of building an IP67-compatible humidity measurement device (with O-ring, cf. Fig. 4) with optimal performance. Detailed information is available on the Sensirion Web site.译文:相对湿度传感器系统的正确设计湿度传感器系统精度及响应特性的优化1.综述为了在相对湿度的应用方面对传感器做出正确的选择,了解和评估那些起决定作用的因素是非常重要的。
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参考资料原文:Capacitive sensors and the main features of the basic concepts: The measured volume of the machinery, such as displacement, pressure change is converted to the sensor capacitance. It is the sensitive part of the capacitor with variable parameters. Its most common form is composed of two parallel electrodes, a very inter-air as the medium of the capacitor, if the neglect edge effects, the capacitance for the capacitor plate ε A / δ, where εis a very inter-medium dielectric constant, A two electrode effective area covered by each other, δ is the distance between two electrodes. δ, A, εone of the three parameters will lead to the change in capacitance changes can be used for measurement. Therefore capacitive sensors can be divided into polar distance change type, change type size, media type three types of changes.Most from the changes in small type generally used to measure the linear displacement, or as a result of force, pressure, vibration caused by changes in polar distance (see capacitive pressure sensors). Change type size generally used to measure the angular displacement or linear displacement larger. Changes in media type commonly used in level measurement and a variety of media, temperature, density, humidity measurement. The advantage of the sensor capacitor structure is simple, inexpensive, high sensitivity,过载能力strong, good dynamic response and high temperature, radiation, vibration and other adverse conditions of strong adaptability and strong. The disadvantage is that there are non-linear output, parasitic capacitance and the distributed capacitance on the sensitivity and accuracy the impact of larger and more complex circuits, such as connectivity. Since the late 70s, with the development of integrated circuit technology, a packaging and micro-measuring instrument with capacitive sensors.This new type of distributed capacitance sensors can greatly reduce the impact to overcome the inherent drawbacks. Capacitive sensor is a very wide use, a great potential for development of the sensor.Capacitive sensor working principle:Capacitive sensor surface of the induction of two coaxial metal electrode composition, much like "open" capacitor electrode, the two electrodes form a capacitor, in series with the RC oscillation circuit. Power when connected, RC oscillator is notoscillating, when a goal of moving around electrical capacitor, the capacitor capacity increased, the oscillator to start oscillation. Circuit after the passage of the deal, will be two kinds of vibration and vibration signals into switching signals, which played a detection purpose of the existence of any objects. The sensor can detect metal objects, but also to detect non-metallic objects, metal objects can move away from the largest, non-metallic objects on the decision to move away from the dielectric constant material, the greater the dielectric constant materials, the availability of action the greater distance.Application of capacitive sensors:Capacitive sensor can be used to measure linear displacement, angular displacement, vibration amplitude, especially suitable for measuring high-frequency vibration amplitude, precision rotary axis accuracy, acceleration and other mechanical parameters. Pole-changing type of application from a smaller displacement in the measurement range to several hundred microns in 0.01m, precision can reach 0.01m, a resolution of up to 0.001m. Change type size larger displacement can be measured, for the zero-range a few millimeters to a few hundred mm, 0.5 percent better than the linear resolution of 0.01 ~ 0.001m. Capacitive angular displacement sensor point of view and the dynamic range to a few degrees, a resolution of about 0.1 "up to the stability of the zero angle-second, widely used in precision angle measurement, such as for high-precision gyroscopes and accelerometers tilting . capacitive measurement sensor can measure the peak amplitude for the 0 ~ 50m, a frequency of 10 ~ 2kHz, sensitivity is higher than 0.01m, non-linear error of less than 0.05m.Capacitive sensor can also be used to measure pressure, differential pressure, level, surface, composition content (such as oil, the water content of food), non-metallic coating materials, such as film thickness, dielectric measurements of humidity, density, thickness, etc., in the automatic detection and control systems are also often used as a location signal generator. Capacitive differential pressure sensor measuring range up to 50MPa, an accuracy of ± 0.25% ~ ± 0.5%. Capacitive sensor for measuring range of the thickness of a few hundred microns, resolution of up to 0.01m. Capacitive Proximity Switches can not only detect metal, but also can detect plastic, wood,paper, and other dielectric liquids, but can not achieve the ultra-small, the movement distance of about 10 ~ 20mm. Electrostatic capacitive level switch is widely used in detection is stored in the tank, hopper, such as the location of containers in a variety of objects of a mature product. When the capacitive sensor measuring metal surface conditions, from the size, vibration amplitude is often used very variable from unilateral type, when the measured object is a capacitor electrode, and the other electrode in the sensor inside. This type of sensor is a non-contact measurement, dynamic range is relatively small, about a few millimeters is about the precision of more than 0.1m, a resolution of 0.01 ~ 0.001m.译文:电容式传感器的基本概念及主要特点:把被测的机械量,如位移、压力等转换为电容量变化的传感器。