Key Engineering Materials Vols. 381-382

Abstract: Recently, ultra-precision machining of components and dies for information and communication industries, such as fresnel mirrors, diffraction lens, and die for super high intensity reflective sheet is one of the major target. To machine three-dimensional micro patterns, such as super high-intensity reflective sheets, ultra-precision and mirror surface fabrication processes are required. It has been reported, however, that continuous cutting, such as turning or shaping, is more suitable to ultra-precision machining. Many researchers have studied the manufacturing process of reflective sheet dies to obtain high form accuracy and surface quality. In this paper, ultra-precision shaping system was developed to fabricate micro patterns mechanically. In order to estimate performance of the shaping system, micro V-shaped grooves and tetrahedron pattern arrays for a super high intensity reflective sheet was applied. Also, a new measuring technology to inspect form and machining errors of a machined tetrahedron patterns was proposed. The results show that shaping system has a positioning accuracy of x, y, z axis with 100, 10, 10nm resolution, respectively. Micro V-shaped grooves could be machined at various depths and micro tetrahedron patterns with a good quality were obtained as well.

Abstract: In this paper we study on a novel method to distinguish the loading location on structures based on optical fiber network. The principle of detection and monitoring system is illustrated in the paper and the experiments of loading position judgment are conducted. The experimental data and curves meet preferably to the analysis of theory. The results obtained are encouraging offering the possibilities of employing this novel method of loading position judgment in intelligent composite structures. The system of monitoring and analysis is approved to be real-time, effective and reliable and the research in this paper offers a new way of application of the special optical intelligent structure.

Abstract: This paper presents a high precision temperature measurement instrument based on quartz tuning-fork temperature sensor (QTTS) using Artificial Neural Networks (ANN). The advantage of QTTS is a great sensitivity which makes possible to determine the temperature with the accuracy of 0.01 °C , but the QTTS based temperature measurement instrument often appears as erroneous temperature reading when using standard polynomial calibration techniques over a large temperature range. For high precision temperature measurement, a new method is presented to compensate non-linearity of QTTS based instrument using non-linearity compensation model using ANN by Levenberg-Marquardt algorithm to settle its non-linear problem. The hardware and software parts of the system are integrated in a PC-based instrument used for operation and calibration. ANN based modelling and correction technique has been evaluated experimentally, followed by experimental results obtained by applying the method to QTTS calibration.

Abstract: This research is focused on the development of protecting system for window. In detail, we tried to develop pollution preventing system of a glass, mirror, or camera lens. For this, the new method for efficient pollution prevention was designed and the characteristic evaluation for developing the system is partly performed. Formerly, the method using air purge is generally used for preventing the pollution of camera window. However, the conventional method often induces contaminations due to back flow of air purging. These pollutants can be crucial damage to the camera window and peripheral materials especially in clean room condition. And the conventional method always requires air supply, therefore it is difficult to apply the method where air source can not be supplied such as traveling crane located at mountain altitudes. To solve above mentioned the problem, the efficient concept for preventing pollution of camera window is proposed in this research. Without air purging, we proposed the new method using repulsion induced by electrifying dirty or moisture to positive magnetic force with high-voltage charge and then injecting gas to the ITO(Indium Tin Oxide) coating window for generating positive ion. To sum up, in this research, we aim to develop an efficient pollution preventing system for camera window based on the new method through characteristic evaluation and stabilization of the designed system.

Abstract: In this paper, we propose novel measurement method that can measure the alignment states of the object in four degrees of freedom, simultaneously; those are pitch, roll, yaw, and height variation. This method mainly utilizes a laser diode, a reflective-type diffraction grating, and two-dimensional position-sensing detectors. The diffraction grating is attached on the object that we are interested. The pitch, roll, yaw angle and height variation can be obtained from the geometric relation among the distance between the grating surface and sensors, displacement of beam spot on sensor surfaces, and angle of diffraction. The experiments to verify the feasibility of the method are carried out. The repeatability and comparison of the measured values and numerical values are verified by experiments. The experimental results show good matches with theoretical values and good repeatability. The results show that our proposed method is effective for measuring 4 DOF of object.

Abstract: To improve vehicle fuel economy and to reduce environmental damage, higher efficiency and optimization of each component in automotive air conditioning system are required. Durability test is a very important process for the research and improvement of A/C system. The refrigerant compressor reliability can be validated based on durability tests. A compressor durability test bench was designed in accordance with ISO Standard 917 and ASHRAE Standard 23. The developed system is constructed for the continuous operation over long period of time to allow for compressor endurance testing at extreme conditions. In order to simulate the under hood conditions, this system offers environmental-controlled compressor chamber. The refrigeration circuit consists of a fixed displacement compressor with cycling-clutch powered by an electric motor with a frequency inverter. The pressures and temperatures at the inlet and exit of compressor can be controlled based on the endurance testing requirements. The experimental bench is flexible and allows a wide range of investigations to be carried out.

Abstract: Reducing residual vibration is very crucial to enhance the speed and precision of XY stages which are often employed by manufacturing/measuring machines. Input shaping is known to be a very effective tool for suppressing such residual vibration without introducing any complicated sensors and feedback control. This paper investigated the effects of input command discretization parameters in real-time input shaping, such as discretizing interval and duration time, on the dynamic performance of a XY stage equipped with servo motors. A simulation model is established to investigate the dynamic performance of the XY stage. In order to evaluate the real-time input shaping parameters on the performance of the XY stage, two fundamental input shaping schemes, ZV(zero vibration) and ZVD(zero vibration and derivative), are implemented and tested with the discretizing interval and duration time varied. The experimental results provide a strategy to gain better performance.

Abstract: This abstract presents the development of an ultra-precision motion controlled positioning stage for nanometer positioning over a working volume of 50 mm × 50 mm × 4 µm at an accuracy of better than 10 nm that is traceable to the national standards. The positioning stage is designed to use various probing systems to perform “pick and place” manipulations and scanning of large specimens, including biological. The system is comprised of a two-axis, long-range stage and a 6 degree-of-freedom (DOF) short-range stage. The long-range stage is responsible for coarse motions of up to 50 mm, while the short-range stage is responsible for correcting positioning errors generated by the long-range stage to achieve nanometer level accuracies. The system will be housed in a vacuum chamber operating at a vacuum pressure of better than 10-3 Torr. The vacuum chamber is also designed to act as an environmental chamber where different gases can be used depending on the measurement task. The initial results of the fully developed positioning stage will be presented at the conference.

Abstract: To meet the demand of large displacement measurement instrument with nanometer precision, this paper introduces the metrological grating with the nanometer measurement precision and large displacement, based on two times' Moiré fringe principle. Its basic principle is that two indicated gratings are fixed on the same measuring base scale, when they move relatively to the scale grating, two groups of one time Moiré fringe will be produced, then two groups of lens are adopted to make the fringe move oppositely, at last the two times Moiré fringe will be produced through interference on the photoelectronic receive element. By subdivision of the two times Moiré fringe, this system can achieve 2.70×10-10m measurement resolution. In addition, this paper also analyse the optics system and light source.

Abstract: This paper investigates the lag time and the highest working frequency of Fiber Bragg Grating strain sensor in which strain wave transfers to bare FBG by analyzing the transmit course of the strain wave. The results show that the FBG strain sensor is applicable to the measurement of low frequency vibration in engineering. As its application, FBG strain sensors are used in the shake table test of offshore platform model and show good capability in measuring the dynamic strain of vibration system with low frequency.