Abstract:Stroboscopic white light interferometry (SWLI) has been known as a useful measurement technique for vibrating samples such as micro electro mechanical systems (MEMS) ormicro-opto-electro-mechanical systems (MOEMS) because it enables dynamic mode reconstruction and characterization of the tested system. The technique has been extended to measure a microstructure having an individual vibrating excitation source which cannot be detected or analyzed in advance by the traditional stroboscopic method. To provide a comprehensive insight into this newly developed technique, this chapter presents the theory, technical methodology and experimental results as well as analyses of the techniques for various applications. The technology provides an effective method in reconstructing and analyzing dynamic behavior of MEMS, MOEMS or even bio-objects in a micro- or nano-scale. Some experimental results and analyses have been provided to verify the feasibility and accuracy of the developed techniques with respect to various applications.

Abstract:Fiber optical spectral-domain white-light interferometry (WLI) has the advantages of high precision, large dynamic range and engineering practicability, and it has been found widely applications in fiber optical sensing and precision measurement. In this paper, we review the development of fiber optical spectral-domain white-light interferometry, and focus on our work about the fiber optical spectral-domain WLI based on phase measurement technology, including the Fourier transform WLI and relative measurement, wavelength scanning WLI, phase-shifted WLI, stepped phase-shifted WLI, wavenumber scanning WLI, and cross-correlation WLI. Applications of this technology in fiber optic temperature, pressure, and strain sensors are demonstrated.

Abstract:The microchip laser self-mixing interferometer is different from the Michelson interferometer in principle. The main difference is that the beam of the laser self-mixing interferometer is amplified by the amplifying medium in the laser after it has been irradiated on the object to be measured and reflected back. The laser self-mixing interferometer developed by the author's research group has achieved a measurement speed of more than 1 m/s, and the environmental error was as small as 40 nm for an air path of 10 m. It has all solid state, can measure the displacement of "black" target, and has reached the technical index of the traditional laser interferometer. If the optical interferometer using a spectral lamp as light source is considered as the first-generation interferometer and that using He-Ne laser as the second-generation interferometer, the solid laser self-mixing interferometer can be regarded as the third-generation laser interferometer because of its laser "self mixing" principle.

Abstract:The recent progress of probes for coordinate measuring machine(CMM) was reviewed. The elastic mechanisms for the probes based on elastic strings and leaf springs have been designed. A typical structure, the stiffness model of the elastic mechanism was established. The elastic mechanisms with different shapes have been verified by simulation using ANSYS software. Several kinds of optical sensors and eight micro/nano probes of CMM developed by the author’s team were introduced. The performance of the probes were verified by experiment and tested. Finally, the research and development trends of the micro/nano probes for CMMs were summarized and prospected.

Abstract:It is a hot research direction at present to measure the three-dimensional (3D) profile of complex curved-surface rapidly and accurately. Compared with the existing measurement methods, the fringe projection profilometry (FPP) has extensive applications for its advantages, such as non-contact measurement, fast speed and dense reconstruction point cloud. It has been widely applied in reverse engineering. In this paper, a FPP system was built to measuring the complex curved-profiles. To improve the measurement accuracy, key technologies of fringe projection contour measurement such as phase error calibration and compensation, precise projector calibration, simplification of high-order calibration model and quick identification of valid points are thoroughly studied. Finally, the profile of an aero-engine blade is measured using the system. Experimental result shows that the maximum measurement deviation is not greater than 0.05mm.

Abstract:Precision measurement technology is an important guarantee for product quality in the large equipment manufacturing industry represented by aerospace, aviation and shipbuilding. At present, the traditional single station measurement system represented by laser tracker can no longer meet the requirements of super large space and high efficiency measurement. As a distributed measurement system, workshop Measurement Positioning System has been widely used in the advanced equipment manufacturing industry because of its advantages of good scalability and parallel measurement. The basic sensing mechanism of workshop Measurement Positioning System is described in detail, the key technologies of the whole system are summarized, and the related industrial applications of the workshop Measurement Positioning System are introduced.

Abstract:As one of the key equipment for non-destructive testing,ultrasonic phased array instrument is of great significance for internal defect analysis, parameter detection and failure evaluation of materials. This paper starts with the principle of phased array technology and analyzes the working mechanisms of key modules such as coded excitation, delayed focus, digital signal fast processing, big data transmission and dispatching module. According to the requirements of the instrument detection performance index, in-depth researches were conducted on the key technologies from the aspects of real-time, flexibility, and precision of the instrument, and experiments were carried out for verification of the implementation of key modules. The research results have important practical value for the high-precision, high-speed, and high-efficiency of nondestructive testing instruments.

Abstract:Gear integrated error technology was one of the worldwide leading technologies developed in China in the early 1970s and had been widely promoted and applied, which had made great contribution to the progress of China gear industry. However, the development and application of gear integrated error technology have entered a bottleneck period over the past 20 years. With the emergence of new technical conditions, some traditional problems of gear integrated error technology can be solved by these innovative solutions, which make the inherent advantages of high measurement efficiency and rich information about gear integrated error technology more prominent. The gear integrated error technology is expected to enter in a new period of rapid development. The development history and research status of gear integrated error technology are summarized. The difficulties and key problems in the elementary theory of the gear integrated error technology are analyzed. The feasible solutions, breakthrough directions and future research trends of the problems above are given, which provide a certain amount of reference and basis for the technology and theory of gear integrated error in the upcoming development.

Abstract:Wheelsets are the main components of movement and force of trains. Wheelset fault is one of the main causes that threaten the safety of trains. The rapid and accurate measurement of the geometric parameters and defects of wheelset can effectively reduce the accident rate and the maintenance cost, and provide the scientific decision-making basis for the design and manufacture of wheel and rail. It has become the research focus in the relevant fields in the world. In this paper, based on a brief description of the development of wheelset geometric parameter detection, our work on the dynamic measurement of geometric parameters and defects in the past 20 years is introduced. We first proposed the principle for quantitatively measuring the wheel tread abrasion and circumferential wear using a parallelogram mechanism, and then put forward the method for accurately measuring the tread diameter using one-dimensional laser displacement sensors and the method for measuring geometric parameters and defects using multi-line lasers. We also developed several different types of wheelsets on-line measurement systems that have been applied to the railway site. The development trend of wheelset inspection is discussed in the end of this paper.