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邵, 毅敏 ; 久米原, 宏之 ; 根津, 紀久雄
概要:
application/pdf<br />Journal Article<br />Extracting symptom of bearing faults from noisy signal is a key problem to detect early faults of machinery. An effective method is presented for improving the signal to noise ratio by the
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wavelet transforms. The paper, which is Part I of a pair, describes wavelet de-noising algorithms and their properties. The relationship between the thresholds for wavelet coefficients and the ability of wavelet de-noise under Gaussian noise is discussed. The advantage of the wavelet de-noising procedure on simulated data is illustrated. Simulated results have shown that using wavelet de-noising procedure is an effective means to extract the signal from noisy data.
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| 2.
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邵, 毅敏 ; 久米原, 宏之 ; 根津, 紀久雄
概要:
application/pdf<br />Journal Article<br />Extracting symptom of bearing faults from noisy signal is a key problem to detect early faults of machinery. An effective method is presented for improving the signal to noise ratio by the
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wavelet transforms. The paper, which is Part II of a pair, illustrates the advantage of the wavelet de-noising procedure on a range of practical examples. We have made a comparison of failure detection-ability between envelope estimator and wavelet-based estimator under the noise condition of machinery. Experiment results have shown that using wavelet de-noising procedure is an effective means to extract early symptoms of machine fault form the heavy noise condition of machinery.
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邵, 毅敏 ; 時任, 朋也 ; 根津, 紀久雄
概要:
application/pdf<br />Journal Article<br />Improving signal to noise ratio is a key problem to detect early faults of machinery under environment noise conditions. An effective method is presented for improving the signal to noise
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ratio by the adaptive neural network. This paper has made a comparison of failure detect-ability between least-mean-square (LMS) algorithm and adaptive neural network under heavy environment noise conditions. Experiment results have shown that using adaptive neural network is an effective means to extract early symptoms of machine fault under heavy environment noises and low rotating speed conditions.
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松原, 雅昭 ; 伊澤, 悟 ; 平尾, 典盟 ; 毒島, 康二 ; 小山, 哲 ; 町田, 康治 ; 川田, 大介 ; 坂本, 賢治 ; 根津, 紀久雄
概要:
application/pdf<br />Journal Article<br />The authors developed a new testing equipment for studying statically indeterminate fracture mechanics. Its development purpose is to clarify load history-dependency of the collapse load.
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The equipment has two actuators orthogonalized. The horizontal actuator applies the axial force and the perpendicular one does the bending moment. In the experiment for examining the effect of load hysteresis on the collapse load, both actuators can keep the preceding load to the constant load value, until axial force and bending load reach the theory collapse point. The actuators can apply the following load under the displacement control in the experiment. The performance of the equipment was confirmed by demonstration tests using single-edge notched specimens of SUS 304 steel. The experimental result clarified load historydependency on collapse load in SUS 304 single-edge notched member subjected to combined tension and bending.
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金森, 康継 ; 根津, 紀久雄
概要:
application/pdf<br />Journal Article<br />In the small-diameter pipe thrust method, the successful operation is dependent on the experience of skilled operators. Because of this, we forecast that we cannot cope with increasing work
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demand in the future. Therefore, improvement of the control system is required. The objectives of this study are to examine the auto steering control method by means of a construction experiment using a model plant and to compare the accuracy of the sequence, the fuzzy, and the neural network-driven fuzzy controls with the manual one.
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Duong-Phuoc, AN ; 根津, 紀久雄 ; 阿久戸, 庸夫
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application/pdf<br />Journal Article<br />Model reference adaptive control (MRAC) of a nonlinear uncertain plant subjected to disturbance is considered. No prior knowledge about the structure of uncertainties is assumed, nor is any
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constant bound on their values. The Lyapunov type of stability is analyzed. A MRAC law has been developed which provides stable tracking. The paper includes an application of the developed adaptive controller to the control of an electric vehicle which is considered to be an uncertain nonlinear system.
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An, Duong-Phuoc ; 根津, 紀久雄 ; 阿久戸, 庸夫
概要:
application/pdf<br />Journal Article<br />This paper is concerned with the design of a slide mode control system from the view point of practical application. The problem is treated using the asymptotic reaching law method for
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assuring global stabilization, and the chattering phenomenon is alleviated by the saturated function of the boundary layer The design algorithm is simple and applicable to a nonlinear system including disturbances and uncertainties with high robustness. Its effectiveness is proven by simulation as well as a bench experiment of a brushless motor vehicle.
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An, Duong-Phuoc ; 根津, 紀久雄 ; 阿久戸, 庸夫
概要:
application/pdf<br />Journal Article<br />This paper is concerned with the design of a nonlinear tracking control system
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utilizing recent H^∞ control theory. We introduce a reference system according to an actual system and leading to a state tracking error system. Then we set the condition of equilibrium state for this system. As a result, we turn the nonlinear tracking control problem into a nonlinear regulation problem and develop a solution using H^∞ control. It is treated by replacing the Riccati equation in linear H^∞ control with the Hamilton-Jacobi equation ; finding the solution of the Riccati equation thus entails finding the so-called generating function which is the Hamilton Jacobi equation's solution. From the generating function we can calculate the H^∞ optimal feedback function of the nonlinear tracking control system under the condition of minimal norm of the transfer function from disturbance to output. Its effectiveness is proven by application to the longitudinal control of an electric vehicle. The results are shown by simulation as well as bench experiment.
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神宮, 利夫 ; 永倉, 和郎 ; 根津, 紀久雄 ; 坂本, 賢治
概要:
application/pdf<br />Journal Article<br />The crack propagation velocity in tensile fracture is determined by comparison of the unloading wave observed by the strain gage method with the theoretical analysis based on postulating the
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crack growth models which are backed by the fractographic analysis using the photograph taken by the scanning electron microscope (SEM). The effect of elongation, contraction of notch bottom and load rate just before rupture on the crack propagation velocity is investigated using the notched round bar specimens of annealed JIS-SS41, S45C and quenched SKS93 steel. The fracture surface of SS41 and S45C is a dimple and SKS93 a cleavage. The deformation of SS41 is largest and in turn S45C, SKS93. It is shown that the crack speed slightly decreases as elongation or contraction of notch bottom increases. Particuraly, the decrease of crack speed of quenched SKS93 is a very little. The reduction of crack speed attributes to softening of notch bottom.
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| 10.
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小島, 宏行 ; 小山, 清 ; 根津, 紀久雄 ; 坂本, 賢治
概要:
application/pdf<br />Journal Article<br />In this paper, the swing-up control method of a pendulum by a horizontal one-link robot is presented, and the experimental results are demonstrated. In the design of the control systom,
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first, the equations of motion of the mechanical system consisting of the robot and the pendulum are derived. Second, the trajectory planning for the swing-up control of the pendulum is investigated by the numerical simulation about the pendulum. In this trajectory planning, the sinus control command of the joint angle is used. Then, the feedforward control voltage of the servomotor are obtained by applying inverse dynamics to the equation of motion with respect to the robot. Furthermore, it is demonstrated by the experimental results that the pendulum can be swung up by adjusting the amplitudes of the sinus control command of the joint angle that is obtained in trajectory planning.
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