System and Measurements

Yong Sang

• Editore: De Gruyter
• Anno: 2020
• ISBN:
  9783110624793
• Edizione: 1
• Argomento: Tecnología e ingeniería
• Categoria: Automatización en ingeniería

This book provides the basic concepts and fundamental principles of dynamic systems including experimental methods, calibration, signal conditioning, data acquisition and processing as well as the results presentation. How to select suitable sensors to measure is also introduced. It is an essential reference to students, lecturers, professionals and any interested lay readers in measurement technology.

1 Introduction to measurement technology

System and measurements is an important technological course in mechanical engineering education, which provides students with basic concepts and the fundamental principles of measurement such as experimental methods, calibration techniques, signal conditioning methods, real-time acquisition and processing of field data, selected sensors for mechanical engineering and display of data results. After learning this course, students will acquire the following abilities:

1. An ability to grasp the methods of data acquisition and data processing
2. An ability to analyze instruments with different input conditions (zeroth-order system, first-order system and second-order system)
3. An ability to apply the sampling and signal conditioning principles learned in the classroom to measuring instruments
4. An ability to use software and hardware for data acquisition
5. An ability to synthesize an individual data acquisition project
6. An ability to select the suitable sensors for temperature, displacement, force, acceleration, pressure and flow and the corresponding instrumentations
7. An ability to describe experimental facilities and experimental procedures, collect data, write reports, analyze data and represent field data
8. An ability to complete group work and share results with others

In this chapter, students will know the history of measurement technology, basic concepts of measurement technology, applications of measurement technology, new trends of measurement technology and world’s famous manufacturers in the measurement field.

1.1 History of measurement technology

The emergence of measurement technology can be traced back to the distant ancient times, and the development of barter trade promoted the measurement of weight and the emergence of scale. Original measurement technologies are also used in other areas, such as measuring buildings and land, measuring calendar time and measuring astronomical geography. In ancient times, people can accurately measure the angle of refraction of light and determine the meridian arc of the earth. In the sixteenth and eighteenth centuries, the rapid development of physics greatly facilitated the advancement of measurement technology. Physics based on experiments relies entirely on measurement technologies, and has invented some advanced measuring devices such as microscopes, barometers and thermometers. At the turn of the seventeenth century, measurement accuracy was further improved, using an accurate astronomical measurement device that enabled Johannes Kepler to determine the rotation of the planet in an elliptical orbit. Great scientists such as Galileo Galilei and Isaac Newton pioneered measurement theory and developed many instruments based on physical phenomena.

With the development of steam engines, machining accuracy requirements of mechanical parts are getting higher and higher, which greatly increases the level of measurement technology. In the field of machining, Vernier caliper was invented by French mathematician Pierre Vernier in 1631, which greatly improved the measurement accuracy of the parts. At the same time, the emergence of other high-precision dimensional measuring devices has been promoted. In the nineteenth century, people established the principles of measurement technology and metrology theory, and used the metric system to unify the measurement standards in machinery manufacturing. Johann Carl Friedrich Gauss made significant contributions to measurement technology and developed the least squares method, random error theory and unit absolute system. Measurement technologies are not only applied in scientific research, but also used industrially for measurement of heat and electricity. At the beginning of the twentieth century, the development of measurement technology entered a new stage: advanced technologies such as electronics, optics and computers have also been introduced into the field of mechanical measurement achieving high-precision measurement of many physical quantities, and the instrument manufacturing industry has been further improved. After the Second World War, the development of measurement technology has made a leap forward. With the advent of automation and computer technology, measurement technology has become the core of control measurement and data acquisition.

Measurement technology is very important for all scientific and technical fields (mechanical, electrical, optical and acoustic signals, etc.). It is the most important part of mechanical equipment in every manufacturing process. Modern measuring equipment is more powerful. The measurement results can be automatically recorded and mathematically processed. Remote automatic control can also be implemented using the network. The process of making measurements with modern measuring devices involves purposefully converting the measurand into the most convenient form for human or machine perception. The electrical measuring instrument such as ammeter or voltmeter can be used to convert the electrical quantity into a mechanical displacement indicating the magnitude of the current or voltage. Some mechanical measuring devices such as calipers, micrometers, spring scales, mercury thermometers and spring pressure gauges work in this way. Further developments in measurement technologies can convert measurements into electrical quantities (such as current, voltage and frequency) rather than mechanical displacement. It is more convenient for all subsequent operations, including the transmission of measurement data, recording and mathematical processing. The main advantages of electrical measurement technology are high sensitivity, low inertia of electrical equipment, the ability to measure many different properties simultaneously and the ability to measure slow and fast changes. Electrical measuring devices can also easily transport data over long distance wires and convert the measurement results into signals during the monitoring process.

Modern measurement technologies have a lot to offer in the measurement of mechanics, optics, acoustics, thermal and physical chemistry. Electromagnetic measurement, radio measurement, frequency measurement and radiation measurement can be realized. For different measurement scales, the measurements are used in a completely different way. Measurement technologies can be used to measure the mechanical stress on the surface of the part, the vibration of the machine and the random nature of the machining accuracy (correlation function, power spectrum). In recent years, with the development of computers, digital measurement technology has emerged, which converts analog quantities into digital quantities, and it is very easy to transfer measurement data into computers through the form of field buses. A number of new measuring devices with high integration, intelligence, information and modernization have been developed. These devices or technologies include fiber-optic grating measuring device based on optical fiber material, low-light image measuring device that breaks the application of human visual limit, intelligent measuring device that can take full advantage of big data, femtosecond laser detection technology based on femtosecond technology, quantum measurement technology widely used in medical and health fields, and seismic transverse wave measurement technology applied in geological exploration, petroleum and coal field exploration.

The current development trends of measurement technology are very clear and the most important features are as follows: (1) measurement accuracy, reliability and measurement speed are significantly improved, and measurement error is reduced to less than 0.01%; (2) measuring instruments toward miniaturization and low power consumption; (3) expanding the measurement range of measuring equipment, including measuring the quantity that cannot be measured before; (4) the digital instrumentation equipment has achieved unprecedented development, and the development of embedded single-chip microcomputer has enhanced the measurement function of instrumentation; (5) the development of measurement technology is moving toward network and big data; and (6) the latest scientific results have facilitated measurement devices based on new working principles.

Many measuring instruments are currently used in various fields, and measurement technologies are part of the curriculum of technical higher education institutions in the world for students to learn. Many scientists and researchers are engaged in the research of measurement technology, and their latest research results are published in the professional journals of measurement technology for peer learning. Worldwide, the following journals devoted to the problems of measurement technology are published regularly: IEEE Transactions on Instrumentation and Measurement (published by the Institute of Electrical and Electronics Engineers Inc., USA), IEEE Instrumentation and Measurement Magazine (published by the Institute of Electrical and Electronics Engineers Inc., USA), IET Science, Measurement and Technology (published by the Institution of Engineering and Technology, UK), Measurement and Control (UK) (published by SAGE Publications Ltd, UK), Measurement Science and Technology (published by the Institute of Physics Publishing, UK), Measurement, Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME (published by the American Society of Mechanical Engineers, USA), Instrumentation Science and Technology (published by Taylor and Francis Inc., USA), Journal of Instrumentation (published by the Institute of Physics Publishing, UK), Optoelectronics, Instrumentation and Data Processing (published by Allerton Press Incorporation, USA), Instrumentation Mesure Metrologie (published by Lavoisier, France), Instruments and Experimental Techniques (published by Maik Nauka Publishing/Springer SBM, Russia), Modelling, Measurement and Control A/B/C (published by AMSE Press, France), Mediterranean Journal of Measurement and Control (published by Softmotor Ltd., UK), Journal of Applied Measurement (published by JAM Press, USA), Measurement Science Review (published by Slovak Academy of Sciences – Inst. Measurement Science, Germany), Measurement Techniques (published by Springer New York LLC, USA), Metrology and Measurement Systems (published by Polish ACAD Sciences Committee Metrology and Res Equipment, Poland), Transactions of the Institute of Measurement and Control (published by SAGE Publications Ltd, UK), Flow Measurement and Instrumentation (published by Elsevier Ltd, UK), ...