机械工程测试技术(英语)
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• Amplifiers • Filters • Special purpose circuits
Course Contents (cont.)
• Chapter 5: Sampling, Digital devices and Data acquisition
– Sampling – D/A converter, A/D converter – Data-Acquisition system components
– input signal: the excitation to the system, – output signal: the response to the system.
• Experimental constraints of a signal
– An experimental signal is the image of a physical process and must be physically achievable.
• 《工程测试技术》，清华大学出版社 • 华中科技大学机械专业精品课程《工程测
试技术基础》
http://mse.hust.edu.cn/gccsjsjc/index.html • 《Theory and design for mechanical
measurements》, 4th edition, R.S. Figliola / D.E.Beasley, Wiley
– Static quantities and dynamic quantities
• Static quantity: does not vary or varies slowly with time.
• Dynamic quantity: varies rapidly with time.
• Static measurement:the measurement of a static quantity.
• Chapter 6: Sensors and Measurements
– Sensors – Strain Measurement – Temperature Measurement – Flow Measurement
Textbooks
• 《机械工程测试原理与技术》，秦树人， 重庆大学出版社
Noise
• Definition:
An unwanted perturbation to a wanted signal.
• Signal-to-noise ratio (S/N or SNR): a measure of the extent of signal contamination by noise, expressed as
• Some questions to ask:
• What’s the relationship between the measured value and the real value of a variable?
• How to devise a measurement or test plan?
system • Course contents • Grading
Basic Concepts of Measurement Methods
• Measurement:
– Examples: scale, race, thermometer
An act of assigning a specific value to a physical variable
-- Lord Kelvin (William Thompson)
• Early measurements:
➢ Length (distance), time, area and weight, etc.
➢ The rapid development of science and technology has invigorated measurement technology, and the development of modern electronics, especially the information technology has pushed forward further its development.
• Output stage:
It indicates or records the value measured. This might be a simple readout display, a marked scale, or even a recording device.
• Signal conditioning:
• Sensor:
sensor
A device that receives and responds to a
signal or stimulus
• Transducer:
It converts this sensed information into a detectable signal, which might be electrical, mechanical, optical or otherwise. The goal is to quantify the sensed information
The extensiveness, essence and scientific significance of measurement technology:
➢“Whatever exists, exists in some amount.” ➢“I often say that when you can measure what you
are speaking about and express it in numbers, you know something about it, and when you cannot measure it, when you cannot express it in numbers, your knowledge is of meager and unsatisfactory kind. It may be the beginning of knowledge, but you have scarcely, in your thought, advanced to the stage, whatever the matter be.”
• How to interpret the measured data?
Applications of mechanical measurements
• Machine part, vibration measurement
• Flight of an aircraft: measurements of its course, speed, acceleration, mileage, etc.
Grading
• Homework: 10% • Attendance: 5% • Final: 85%
Chapter 2: Signal analysis and
processing
• Definition: all the physical quantities or variables of systems, such as: force, displacement, acceleration, voltage, current, light intensity, etc.
domains – Signal convolution and correlation – Digital signal processing
Course Contents (cont.)
• Chapter 3: Measurement system behavior
– General Model for a measurement system – Special cases: zero-order, first-order, second-order
Fundamentals of Mechanical Measurement Technology
Before Class
• Self-introduction • Bilingual
Chapter 1: Introduction
• What’s Measurement? • Applications • A template of a general measurement
• On a robot: force sensor, pressure sensor, touch sensor, vision sensor, distance sensor, etc.
Components of a general measurement system
• A general measurement system:
system inertia prohibits any discontinuity. ▪ The signal spectrum is also necessarily bounded and must tend
towards zero when the frequency tends towards infinity.
Signal conditioning equipment takes the transducer signal and modifies it to a desired magnitude.
e.g. amplification, filtering, conversion etc.
• Classification of physical quantities (in terms of time-dependent properties):
• Dynamic measurement:the measurement of a dynamic quantity.
Biblioteka Baidu
Course Contents
• Chapter 2: Signal analysis and Processing
– Signal classification – Signal representations in time and frequency
• or
Ps / Pn
dB 10 log10
• Signal Classifications
– Analog signal, discrete time signal and digital signal
– Deterministic signals and nondeterministic signals
– Constraints for a signal:
▪ Its energy must be finite. ▪ Its amplitude is necessarily bounded. ▪ This amplitude is a continuous function because the source
Measured object Sensor transducer
stage
Signal conditioning
stage
Output Observer stage – Controller Data display and recording
Stem
Display scale
Bulb
Sensor-transducer stage
systems – Step function input and sine function input responses
• Chapter 4: Analog Electrical Devices and Measurements
– Current, voltage and resistance measurements – Analog signal conditioning
Course Contents (cont.)
• Chapter 5: Sampling, Digital devices and Data acquisition
– Sampling – D/A converter, A/D converter – Data-Acquisition system components
– input signal: the excitation to the system, – output signal: the response to the system.
• Experimental constraints of a signal
– An experimental signal is the image of a physical process and must be physically achievable.
• 《工程测试技术》，清华大学出版社 • 华中科技大学机械专业精品课程《工程测
试技术基础》
http://mse.hust.edu.cn/gccsjsjc/index.html • 《Theory and design for mechanical
measurements》, 4th edition, R.S. Figliola / D.E.Beasley, Wiley
– Static quantities and dynamic quantities
• Static quantity: does not vary or varies slowly with time.
• Dynamic quantity: varies rapidly with time.
• Static measurement:the measurement of a static quantity.
• Chapter 6: Sensors and Measurements
– Sensors – Strain Measurement – Temperature Measurement – Flow Measurement
Textbooks
• 《机械工程测试原理与技术》，秦树人， 重庆大学出版社
Noise
• Definition:
An unwanted perturbation to a wanted signal.
• Signal-to-noise ratio (S/N or SNR): a measure of the extent of signal contamination by noise, expressed as
• Some questions to ask:
• What’s the relationship between the measured value and the real value of a variable?
• How to devise a measurement or test plan?
system • Course contents • Grading
Basic Concepts of Measurement Methods
• Measurement:
– Examples: scale, race, thermometer
An act of assigning a specific value to a physical variable
-- Lord Kelvin (William Thompson)
• Early measurements:
➢ Length (distance), time, area and weight, etc.
➢ The rapid development of science and technology has invigorated measurement technology, and the development of modern electronics, especially the information technology has pushed forward further its development.
• Output stage:
It indicates or records the value measured. This might be a simple readout display, a marked scale, or even a recording device.
• Signal conditioning:
• Sensor:
sensor
A device that receives and responds to a
signal or stimulus
• Transducer:
It converts this sensed information into a detectable signal, which might be electrical, mechanical, optical or otherwise. The goal is to quantify the sensed information
The extensiveness, essence and scientific significance of measurement technology:
➢“Whatever exists, exists in some amount.” ➢“I often say that when you can measure what you
are speaking about and express it in numbers, you know something about it, and when you cannot measure it, when you cannot express it in numbers, your knowledge is of meager and unsatisfactory kind. It may be the beginning of knowledge, but you have scarcely, in your thought, advanced to the stage, whatever the matter be.”
• How to interpret the measured data?
Applications of mechanical measurements
• Machine part, vibration measurement
• Flight of an aircraft: measurements of its course, speed, acceleration, mileage, etc.
Grading
• Homework: 10% • Attendance: 5% • Final: 85%
Chapter 2: Signal analysis and
processing
• Definition: all the physical quantities or variables of systems, such as: force, displacement, acceleration, voltage, current, light intensity, etc.
domains – Signal convolution and correlation – Digital signal processing
Course Contents (cont.)
• Chapter 3: Measurement system behavior
– General Model for a measurement system – Special cases: zero-order, first-order, second-order
Fundamentals of Mechanical Measurement Technology
Before Class
• Self-introduction • Bilingual
Chapter 1: Introduction
• What’s Measurement? • Applications • A template of a general measurement
• On a robot: force sensor, pressure sensor, touch sensor, vision sensor, distance sensor, etc.
Components of a general measurement system
• A general measurement system:
system inertia prohibits any discontinuity. ▪ The signal spectrum is also necessarily bounded and must tend
towards zero when the frequency tends towards infinity.
Signal conditioning equipment takes the transducer signal and modifies it to a desired magnitude.
e.g. amplification, filtering, conversion etc.
• Classification of physical quantities (in terms of time-dependent properties):
• Dynamic measurement:the measurement of a dynamic quantity.
Biblioteka Baidu
Course Contents
• Chapter 2: Signal analysis and Processing
– Signal classification – Signal representations in time and frequency
• or
Ps / Pn
dB 10 log10
• Signal Classifications
– Analog signal, discrete time signal and digital signal
– Deterministic signals and nondeterministic signals
– Constraints for a signal:
▪ Its energy must be finite. ▪ Its amplitude is necessarily bounded. ▪ This amplitude is a continuous function because the source
Measured object Sensor transducer
stage
Signal conditioning
stage
Output Observer stage – Controller Data display and recording
Stem
Display scale
Bulb
Sensor-transducer stage
systems – Step function input and sine function input responses
• Chapter 4: Analog Electrical Devices and Measurements
– Current, voltage and resistance measurements – Analog signal conditioning