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論文

論文
小島, 宏行 ; Kato, Gustavo
出版情報: 日本機械学會論文集. C編.  71  pp.2281-2288,  2005-07-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />In this paper, the dynamic behaviors of a two-link hopping robot with two stopper mechanisms are investigated theoretically. In the theoretical analysis, the dynamic behaviors of the two-link hopping robot with two stopper mechanisms are modeled by use of the four phases (phase-A, phase-B, phase-C, phase-D). At the moment when the first joint stops, the state of the system transfers from phase-A to phase-B. Then, at the moment when the second joint stops, the state of the system transfers from phase-B to phase-C. In phase-C, the two-link hopping robot moves in space, and at the moment when the two-link hopping robot lands, the state of the system transfers from phase-C to phase-D. Using the principle of the conservation of momentum and angular momentum, the initial states in the periods of phase-B and phase-C are derived, and the equations of motion of the two-link hopping robot in all phases are obtained. Furthermore, the numerical simulations have been carried out, and it is confirmed theoretically that the hopping and moving action can be performed successfully. 続きを見る
2.

論文

論文
長屋, 幸助 ; 井開, 重男 ; 福島, 俊之 ; 来栖, 明法 ; 樫本, 弘
出版情報: 日本機械学會論文集. C編.  62  pp.2721-2729,  1996-07-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />A solid-type piezoelectric actuator generates a large force, but the generated displacement is significantly small. In particular, the actuator has a large hysteresis between a control voltage and the control displacement. Hence the application of the actuator has been limited to some special areas. This paper presents a linear piezoelectric actuator without hysteresis. The actuator presented has linearization control circuits and a displacement enlargement mechanism made of elastic hinges, so that the generated displacement is in the range of displacements required for vibration control of machines. To control the actuator, a displacement sensor is used in general, but one of the ends of the sensor must be fixed to a wall. This implies that the application of the actuator is limited. Hence in this paper, an acceleration sensor is used instead of the displacement sensor. This enables us to use the actuator as a conventional linear actuator. Theoretical analysis was given, then experimental tests were carried out to validate the method and the analysis. 続きを見る
3.

論文

論文
長屋, 幸助 ; 鄭, 惟
出版情報: 日本機械学會論文集. C編.  61  pp.1343-1350,  1995-04-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />This paper discusses vibration control problems of a cantilever plate with variable width. A moment-type actuator using a moving coil was presented. A mothod for obtaining optimal feedback coefficients was proposed on the basis of neural networks. An analytial solution for the response of the plate under the control using the feedback coefficients was obtained. Numerical calculations were carried out for some typical cases. It is clarified that the present method is valid for controlling vibrations of plates. 続きを見る
4.

論文

論文
長屋, 幸助 ; 石川, 真史 ; 藤沢, 延行
出版情報: 日本機械学會論文集. C編.  61  pp.1381-1388,  1995-04-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />This paper proposes a drag-force-type magnetic levitation actuator consisting of pairs of permanent magnets and electromagnets. For general magnetic levitation actuators, there is a nonlinear relationship between magnetic force and control current, so that a linear control theory is not applicable. In the actuator proposed, the relationship between the force and the current is linear. This implies that the position and velocity feedback controls can be applied without consideration of interferences. A control method using a combination of techniques of disturbance cancellation and optimal regulation was presented taking into consideration the interference between perpendicular and vertical motions. To verify the applicability of present actuator and control method, experimental tests were carried out. 続きを見る
5.

論文

論文
王, 建春 ; 長屋, 幸助 ; 横田, 正二
出版情報: 日本機械学會論文集. C編.  59  pp.2621-2628,  1993-09-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />This paper presents a method for obtaining vibration response of a viscoelastic spiral rod having straight portions on viscoelastic supports. The expressions for calculating frequency response are obtained by means of the transfer matrix method, in which the exact solution of the differential equations with twelve state variables for the static deflection is applied. Inertia forces and rotatory inertia are included by making use of the point transfer matrix, and the bent portions are also considered by including the transfer matrix of coordinates. Numerical calculations were carried out for the rod with both an elastic portion and a viscoelastic portion carrying a mass at the end. In this problem, the rotary vibration is of importance because it generates noise, hence the location of the viscoelastic support which induces the rotary vibration of the mass minimum is discussed in detail. The fuzzy algorithm by which the optimal location of the supports is obtained is also presented. 続きを見る
6.

論文

論文
長屋, 幸助 ; 横田, 勇
出版情報: 日本機械学會論文集. C編.  59  pp.746-753,  1993-03-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />In the preceding related paper, the authors discussed a plate-type magnetic damper with alternative magnetic poles. The paper presented the analytical expressions of eddy currents in the conductor and the damping coefficients for the single row of alternative poles. The damping effects of the damper having alternative poles of a number of rows and columns are different from those of the previous model. The present article discusses the damping increasing mechanisms for the plate-type damper with alternative magnetic poles of a number of rows and columns. The analytical expression for finding the eddy current patterns and the damping coefficient are obtained. Numerical calculations are carried out for some important examples. Since the present article gives the analytical expression and the numerical data of dimensionless damping coefficients, the results may be used directly in the practical design of such devices as vibration absorbers. 続きを見る
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論文

論文
田, 宏奇 ; 長屋, 幸助 ; 井開, 重男
出版情報: 日本機械学會論文集. C編.  58  pp.3614-3620,  1992-06-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />A new magnetic gear transmitting system with an actuator made of an electromagnet is proposed in this paper. The vibration due to the system parameter variations or external disturbance is absorbed by means of changing magnetic fluxes of the electromagnet and the controller is designed by variable structure system (VSS) theory. The theoretical expressions of the transmitting torque, magnetic spring constant and control force versus electric current in the electromagnet were derived. Both the simulations and experiments of this magnetic gear system were carried out by means of the sliding mode regulator and were compared with the PID linear control method. The experimental results confirmed the theoretical analyses. 続きを見る
8.

論文

論文
王, 建春 ; 長屋, 幸助 ; 横田, 正二
出版情報: 日本機械学會論文集. C編.  58  pp.9-16,  1992-01-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />This paper discusses free vibrations of a spiral rod with straight portions on a number of supports. Since the spiral portion is a three-dimensional structure, three-dimensional motions are coupled. Hence, this paper first presents the transfer matrix for a three-dimensional curved rod with supports, then the transfer matrix of a straight rod with supports is joined to that of the spiral rod. The frequency equations for the rod with consideration of three-dimensional motions are obtained. Numerical calculations are carried out for some typical problems. 続きを見る
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論文

論文
長屋, 幸助 ; 杉浦, 光則
出版情報: 日本機械学會論文集. C編.  57  pp.3794-3799,  1991-12-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />Since electromagnetic force is a function of the gap between two magnets, the spring constant has large nonlinearities with respect to the displacement. Hence, the spring constant varies significantly with the initial load. This implies that the linear control theory is not applicable in the range of large displacement. To treat a system with variable initial load and large displacement, the present article presents a procedure for obtaining a linear spring by means of a repulsive-type actuator using permanent magnets and an electromagnet. The analytical expression for the linear spring is presented. Experimental tests were carried out, and the theoretical values are compared with the experimental results. 続きを見る
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論文

論文
長屋, 幸助 ; 関口, 肇
出版情報: 日本機械学會論文集. C編.  57  pp.3800-3805,  1991-12-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />A magnetic damper in which opposite poles are arranged by turns has great deal of damping effects as compared with a normal magnetic damper. However the reason of it has not been clarified, and the analysis has not been reported. To clarify the mechanisms of increasing dampings for the damper, this paper presents an analytical results for the eddy current, and the damping coefficient. Numerical calculations are carried out for some important examples, and the results are compared with those of the normal magnetic damper. 続きを見る