Precision Instrumentation and Measurement

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Authors: Kou Yamada, Tatsuya Sakanushi, Takaaki Hagiwara, Iwanori Murakami, Yoshinori Ando, Shun Yamamoto, Nhan Luong Thanh Nguyen
Abstract: In this paper, we examine the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic. The parameterization of all stabilizing modified repetitive controllers for non-minimum phase systems was solved by Yamada et al. However, when we design a stabilizing modified repetitive controller using the parameterization by Yamada et al., the input-output frequency characteristic of the control system cannot be settled so easily. The input-output frequency characteristic of the control systems is required to be easily settled. This problem is solved by obtaining the parameterization of all stabilizing modified repetitive controllers with the specified input-output frequency characteristic. However, no paper has proposed the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic. In this paper, we propose the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic.
Authors: Manabu Sasajima, Takao Yamaguchi, Akira Hara
Abstract: The acoustic pathway in the enclosure of small headphones is very narrow. Therefore, the speed of sound propagation and the phase change because of the air viscosity. We have developed a new finite element method that considers the effects of damping due to air viscosity in the sound pathway. The new finite element method is obtained by improving the finite element method proposed by Yamaguchi for porous sound-absorbing materials. Moreover, we have attempted to obtain a numerical calculation of damping due to air viscosity by using the proposed finite element method.
Authors: Takao Yamaguchi, Yusaku Fujii, Toru Fukushima, Tomoyuki Kanai, Kenichi Nagai, Shinichi Maruyama
Abstract: This paper deals with dynamic responses of viscoelastic shock absorbers to protect a finger under impact forces by a sliding rigid object. The outline of the viscoelastic absorber is tube and the cross section of the absorber is in the shape of hollow semi circle. The sliding object having initial velocities collided with the absorbers. And the relevant restoring forces are measured using Levitation Mass Method proposed by Fujii. In this paper, we carry out numerical analysis of dynamic response for the viscoelastic absorbers under the same conditions with the experiment using LMM. The absorbers are modeled using a nonlinear concentrated spring with nonlinear hysteresis. This nonlinear spring is connected to the levitated block, which is modeled by three-dimensional finite elements. The experimental data are compared with the calculated ones using our proposed FEM.
Authors: Yoshio Kurosawa, Takao Yamaguchi
Abstract: We have developed a technique for estimating vibrations of an automotive body structures with viscoelastic damping materials using large-scale finite element (FE) model, which will enable us to grasp and to reduce high-frequency road noise(200~500Hz). In the new technique, first order solutions for modal loss factors are derived applying asymptotic method. This method saves calculation time to estimate modal damping as a practical tool in the design stages of the body structures. Frequency responses were calculated using this technique and the results almost agreed with the test results. This technique can show the effect of the viscoelastic damping materials on the automotive body panels, and it enables the more efficient layout of the viscoelastic damping materials. Further, we clarified damping properties of the automotive body structures under coupled vibration between frames and panels with the viscoelastic damping materials.
Authors: Rong Sheng Lu, Yan Qiong Shi, Qi Li, Qing Ping Yu
Abstract: Recent years, automated optical inspection (AOI) is developed very fast along with the rapid development of the emerging industries of semiconductor, LCD, PCB, optical communication and precision assembly, and also widely used in the industries of robot, automobile, steel, textile, printing, medicine, etc. In this paper, we will take a review of the AOI techniques, which are used for defect inspection on a large surface, such as inspecting the quality of TFT-LCD glass substrate and filter. The AOI system architecture having high inspection speed is illustrated. Some key techniques of light illumination, distributed image processing and convey mechanism, are explained.
Authors: Wen Mei Hou, Xiao Ren
Abstract: The demands of nano-measurement and nano-positioning now in research and industries become the challenge for heterodyne interferometer because its nonlinearity often limits the effective resolution. This paper introduces new developed method for compensation of the nonlinearity in heterodyne interferometer and explains what accuracy can be reached with demonstrations figured by the test results. On the basis of theoretical analyses and experimental investigations it shows which exactness can be expected.
Authors: S. Punthawanunt, T. Phattaraworamet, S. Mitatha, P. Preecha Yupapin
Abstract: This paper presents the use of optical device system for OOK (On-Off Keying) generation. The system consists of a MZI (Mach-Zhender Interferometer) incorporated with NRR (Non-linear Ring Resonator) to generate and communicate in optical communication. The performance of the system is calculated in terms of bit error rate (BER). In simulation, a given Gaussian pulse is input into one arm of MZI, which one part of the input power is coupled into one arm which is connected to the series microring resonators, the other is formed the reference arm. The resonant output signals are obtained by the MZI output port, whereas the alternative switching signals can be seen. The resonant output is propagated into the optical system in the transmission line. By using the practical parameters, the link performance can be calculated which can be used to analyzed system performance.
Authors: Yohsuke Tanaka, Shigeru Murata
Abstract: In this study, we observe the time-series of the stress field of a cantilever beam subjected to a dynamic load by using holographic Particle-Tracking Velocimetry (PTV). The beam (elastic modulus 2822 MPa, 3.95×20.45×2.99 mm3) is composed of a transparent acrylic resin containing dispersed tracer particles (average diameter: 60 µm). The cantilever beam is subjected to a dynamic load (0 N to 10 N over 10 sec) at the tip. We compare the experimental and analytical values of the deflection at t = 10 sec. The RMS error is 24.5 µm with respect to the maximum deflection value of 657 µm.
Authors: Koichi Maru, Yusaku Fujii
Abstract: Integrated laser Doppler velocimeters (LDVs) using integrated waveguide technology are reviewed. LDVs have been widely used to measure the velocity of a fluid flow or rigid object in various research and industries. However, bulk optical systems used in conventional measurement need special care from temperature change and vibration, which become the expected sources of uncertainty in measurement, due to large optical path length. Therefore, the optical system should be more compact. The LDV can be drastically reduced by using a planar lightwave circuit (PLC). The possibility for realizing several types of novel integrated LDVs, including a wavelength-insensitive LDV, a scanning LDV and a multi-point LDV, is discussed.
Authors: Koichi Maru, Yusaku Fujii
Abstract: A method for reducing the size and cost of optical system for precision measurement based on the Levitation Mass Method (LMM) is proposed. In the LMM, a mass levitated using a pneumatic linear bearing with sufficiently small friction is made to collide with the object being tested. The velocity and acceleration of the mass are measured using a compact optical interferometer. The size of the optical system can be drastically reduced by using a planar lightwave circuit (PLC), in which several optical elements are arranged on a planar surface of a silica or semiconductor substrate. Several applications of the PLC to precision measurement will be discussed.

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