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| 1.
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福室, 允央 ; 大関, 健一郎 ; 斎藤, 正人 ; 葛, 徳梁 ; 村上, 岩範 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />A simple and stable energy-storage flywheel system with high temperature superconducting levitation is presented. In order to have stable levitation, a superconductor and a permanent magnet are
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used, and 3 permanent magnets support the top of the shaft. In the part of drive system, 8-poles permanent magnet and 8 coils are used to cancel electromagnetic forces in the radial direction. An electromagnetic damper consisting of permanent magnet for levitation and 4 coils is presented which lies at both ends of the shaft. When the shaft vibrates in the direction perpendicular to the shaft axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the shaft, so that the force behaves like damping forces. Using this system, a control like the sensorless control is performed. Experimental tests have been carried out for the system as just mentioned. It is clarified that our system has stable levitation, and vibrations are suppressed significantly.
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| 2.
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小島, 宏行 ; 羽廣, 憲一
概要:
application/pdf<br />Journal Article<br />In this paper, the residual vibration reduction method of a crane using the optimal trajectory planning is proposed, and the usefulness of the present residual vibration reduction method is
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confirmed both numerically and experimentally. In the optimal trajectory planning, the velocity profile of the trolley is expressed with two fifth-order polynomials, and it is depicted by two parameters obtained by applying some conditions to the fifth-order polynomials. Then, the traiectory is expressed as a function of the chromosome using the two parameters as the genes of the genetic algorithm, and the optimal trajectory of the trolley is obtained by defining the fitness function for the residual vibrations of the load. Furthermore, the numerical calculations been carried out, and it is confirmed that the residual vibrations can be extremely reduced, and the experimental results agree well with the calculation results.
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| 3.
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小島, 宏行
概要:
application/pdf<br />Journal Article<br />This study is concerned with the trajectory planning method of a CP control flexible robot arm by using a genetic algorithm. The flexible robot arm consists of a first rigid link and a second
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flexible link, and the desired trajectory is set to be a straight line. In the trajectory planning, the reference trajectory, as if the flexural displacement of the second flexible link is zero, is expressed by use of a cubic spline function, and the velocity profile in the direction of the desired trajectory is depicted using two fifth-order polynomial functions. The individual chromosome of the genetic algorithm is composed using the parameters of the cubic spline function and the fifth-order polynomial functions as the genes. Then, the fitness function of the individual chromosome for the residual vibration reduction and the trajectory tracking control is defined, and the trajectory planning algorithm is constructed using the genetic algorithm. Furthermore, the numerical calculations have been carried out, and it is confirmed that the residual vibrations can be remarkably reduced, and the trajectory error from the desired trajectory can be considerably reduced.
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| 4.
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Pranoto, Tjahjo ; 長屋, 幸助 ; 細田, 敦史
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application/pdf<br />Journal Article<br />The purpose of this work is to develop a linear damper in the wing of the aircraft. Then it requires the following: (1) The damping force have to be large for low frequency because the vibration
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frequency of the wing is small. (2) It works for small displacement, (3) Its size has to be small which can be stacked in the wing, and (4) Passive damper is desirable. This article presents a new type linear damper, which satisfies the conditions as just mentioned. The damper consists of a number of thin plates with slits. MR fluid is filled in the damper, so that magnetic fields freeze MR fluid. Resisting torque (friction torque) is generated when the plates slide due to the shear of slits of the plates. The damper works against the bending moment of the wing by responding its deflection. The damper is maintenance free, and it is one of passive dampers with a good durability.
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小島, 宏行 ; 戸塚, 輝成 ; 近藤, 厚哉
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application/pdf<br />Journal Article<br />In this report, the rotation control system of the flexible robot arm is constructed with both the desired signal planning algorithm of the joint angle and the tracking controller. The tracking
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controller consists of the PD controller and the disturbance observer. Then, the experiments of the rotation control of the flexible robot arm have been carried out. As the results, it is seen that the residual vibrations of the flexible robot arm can be remarkably reduced. Therefore, the usefulness of the present rotation control system of the flexible robot arm using the desired signal planning method of the joint angle and the disturbance observer is confirmed experimentally.
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| 6.
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小島, 宏行
概要:
application/pdf<br />Journal Article<br />In this report, first, the nonlinear equations of motion of a horizontal one-link flexible robot arm are obtained by use of the mode functions of a cantilever beam with a mass. Then, the algorithm
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of the desired signal planning of the joint angle for the purpose of the reduction control of residual vibrations of the flexible robot arm is derived by use of the initial and final conditions of the flexural displacement of the flexible link and the constraint conditions of the desired signal of the joint angle during the acceleration and deceleration terms as well as the linearized equation of motion of the flexible robot arm. The rotation control system of the flexible robot arm is constructed with the desired signal planning for the joint angle and the PD controller. Furthermore, the numerical simulations of the rotation control of the flexible robot arm have been carried out, and it is confirmed that the residual vibrations of the flexible robot arm can be effectively reduced by the present desired signal planning for the joint angle.
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| 7.
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長屋, 幸助 ; 小林, 譲二 ; 今井, 勝仁
概要:
application/pdf<br />Journal Article<br />This paper presents a method of micro-vibration control of milling machine heads by use of vibration absorber. The principle used in the paper is different from usual absorbers. In the
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present absorber, an auto-tuning vibration absorber is presented in which the absorber create anti-resonance state. When the anti-resonance is used, the damping has to be significantly small, so it is difficult to suppress higher modes. To suppress higher modes, the present article uses autotuning magnetic damper. It damps higher modes, but it also increase first modal vibration. Then a method of optimal auto tuning control is presented in which both principal and higher modal vibrations are suppressed. Experimental tests are carried out for a real milling machine, and cutting tests are also performed.
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| 8.
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長屋, 幸助 ; 小杉, 泰裕 ; 鈴木, 孝明 ; 村上, 岩範
概要:
application/pdf<br />Journal Article<br />A simple but stable non-contact high Tc superconducting levitation system with a vertical shaft has been presented. The system consists of a superconductor and permanent magnets. In the system,
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only a lower end of the shaft is supported by a high Tc superconductor, and the other end is supported by two ordinary permanent magnets. Since the restoring force is small with respect to the radial direction the system becomes unstable when the force act in the radial direction, so it is difficult to drive the shaft by electromagnetic forces in using such as motors. Then, a driving system using electromagnets has been presented, in which the balanced forces act on two opposite sides of the disc type rotor in the axial direction. Since the system has no unbalance force from an analytical point of view, the rotor will be able to rotate without control. In the system, however, since there is the eccentricity between the center of rotation and magnetic center, so vibrations are generated. This study also presents an optimal control method of the vibrations. To validates the proposed system, and the control method, experimental tests have been carried out.
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| 9.
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長屋, 幸助 ; 塚越, 正人 ; 小杉, 泰裕 ; 村上, 雅人
概要:
application/pdf<br />Journal Article<br />The present article discusses a modeling and control of high-T_c superconducting levitation system. The paper first clarifies analytical expressions for obtaining nonlinear levitation force
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given by the present author, then presents at vibration control method in which feedback currents involving frequency weights. In the method, an addition of a square of the displacement and currents in a frequency domain is taken as a cost function. Optimal coefficients of the transfer function of the controller are obtained by minimizing the cost function. Hence, the spillover instability due to the nonlinear vibration will be redriced. Numerical calculations have been carried out for some typical problems. To validate the present method, experimental tests also have been carried out.
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| 10.
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井開, 重男 ; 樫本, 弘 ; 大沢, 恵一 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />This paper presents an actuator with a sensor for controlling vibrations of machines. It consists of a voice coil type electromagnetic actuator connected to piezoelectric sensor and a coil spring.
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The actuator is used for controlling a motor laid on the beam. The disturbance force due to the centrifugal force of the motor is detected by the sensor, and the force which is equivalent to the disturbance force is applied to the motor and the beam by the actuator. This implies that the disturbance force is canceled. The control technique as just mentioned has advantages because it reduces the vibration in the low frequency region, in addition, the actuator becomes compact, and the control force becomes small. But the control is insufficient for controlling the resonance peak. The PD control is available for reducing the resonance peak, but the displacement and velocity sensors are required. In the present article, a method of vibration control of disturbance cancellation combining the PD control is presented in which both the displacement and velocity sensors are not required. The analytical results for obtaining the control current and the response of both the motor and beam have been obtained. To validate the present actuator sensor system and the control method, experimental tests are carried out.
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| 11.
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井開, 重男 ; 樫本, 弘 ; 阿久澤, 享 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />This paper presents a vibration isolation mechanism without resonance. The mechanism is consisting of a linear sliders, ball screw, servo-motor and a table in which there is no spring
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element, so the table behaves like a rigid body. In the mechanism, the servo-motor rotates the ball screw with the same displacement as the base displacement in the opposite direction. Hence the disturbance is canceled. A well known relative displacement feedback control method was first discussed, and it was shown that the method was insufficient for isolating vibrations, then a method of disturbance cancellation was presented. To validate the present mechanism and the control method, experimental tests were carried out for a model of the mechanism.
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| 12.
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長屋, 幸助 ; 来栖, 明法 ; 井開, 重男 ; 志谷, 佳久
概要:
application/pdf<br />Journal Article<br />The vibrations of a structure having a vibration absorber without damper vanish at the anti-resonance frequency theoretically. Hence if the rigidity of the absorber is controlled to produce an
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anti-resonance state according to the forced frequency, the vibrations of the structure can be deleted for sinusoidal forces. However, external vibration force involves higher modes, in general, so the structure is excited by various frequencies. Hence it is difficult to delete the vibrations using the anti-resonance procedure. This paper presents a method to control vibration of structures by combining the auto-tuning control of anti-resonance and optimal dynamic absorbers. Theoretical results under the control have been presented. To validate the present method and the theoretical results, experimental tests have been performed.
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| 13.
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長屋, 幸助 ; 福島, 俊之 ; 井開, 重男 ; 金野, 英介
概要:
application/pdf<br />Journal Article<br />A method of vibration control for a column carrying a mass at its tip subjtected to earthquakes is described. A vibration control mechanism consisting of a gear train for the column is also
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described. Experimental tests have been performed for a model of the present mechanism. It is shown that the vibration displacements and the moments in the column are reduced significantly in comparison with those in a conventional column without the mechanism. In the present column, energies for controlling vibrations are not required because of the use of earthquake force as a control force. Therefore, the column has advantages over the columns having an active vibration control system.
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| 14.
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李, 連進 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />This paper presents a method for optimizing vibration absorbers on a flexible beam by means of a neural network procedure. Analytical results for the response of the beam with multi-absorbers
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have been obtained using a transfer matrix method. To achieve optimal control, a cost function composed of second-order nonlinear forms in terms of the displacement, strain, and frequencies was used. A method of minimizing the function was presented, in which input values, weights and output function were effectively controlled on the basis of the back-propagation procedure of the neural network method. Numerical calculations were carried out for an example problem. It is ascertained that the present method gives a better result than that obtained by the previously published method. The validity of the method and the analytical results was confirmed by experimental tests.
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| 15.
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長屋, 幸助 ; 鄭, 惟
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
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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.
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永井, 健一 ; 小山, 富夫 ; 渡辺, 一実 ; 谷藤, 克也 ; 籠谷, 正則
概要:
application/pdf<br />Journal Article<br />Analytical results are presented for nonlinear vibrations of a timing belt with a rotor pulled by a magnetic force. With application of the Galerkin method to the basic equation, the ordinary
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differential equation in a multi-degree-of-freedom system is reduced. The steady-state responses are calculated using the harmonic balance method. The numerical results show the following conclusions. The resonance frequency in each mode of vibration decreases with the increment of the mass in the rotor. The amplitude of nonlinear response decreases with the increment of the cross section in the belt. The magnetic force acting on the belt changes the characteristics of nonlinear spring from the hardening type to the softening-hardening type. The magnetic force on the belt easily shifts the frequency away from the resonance frequency and facilitates supression of the resonance amplitude.
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遠藤, 正規 ; 長屋, 幸助 ; 渥美, 全弘
概要:
application/pdf<br />Journal Article<br />This paper proposes a method for controlling vibrations of a magnetic levitation table. The system considered in this paper is composed of permanent magnet and a permanent magnet with an
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electromagnet. The vibration is controlled by changing magnetic flux density of the permanent magnet by controlling electrical current in a coil of the electromagnet. Two kinds of control techniques are combined. One is the disturbance cancellation control in which the variation of the levitation force is controlled, which corresponds to the external force due to disturbances, and the other is the state feedback control. Experimental tests have been carried out to discuss the validity of this technique. The experimental results show that the technique proposed in this paper is applicable to isolate vibrations, and the transmissibility can be controlled to be nearly zero.
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長屋, 幸助 ; 杉浦, 光則
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
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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.
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小島, 宏行 ; 根津, 紀久雄 ; 坂本, 賢治 ; 川鍋, 隆 ; 小島, 英男
概要:
application/pdf<br />Journal Article<br />A rapid position control method, to which the feedforward control based on the inverse dynamics is applied, is presented, and the availability is confirmed experimentally and theoretically.
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In the experiment, the linear direct current motor is made with an aluminum coil frame or an acrylic resin frame. Then, it is confirmed that, by the present control method, the moving part of the linear direct current motor can be controlled exactly to the position control command for an arbitrary settling time, without undesirable mechanical vibrations. When the settling time is comparatively long, the wave shape of the control current of the motor is affected mainly by the spring force of the beam. Then, with a decreasing value of the settling time, the inertia force has significant effects on the wave shape of the control current. Furthermore, the numerical simulation results obtained by the finite element method agree well with the experimental results.
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長屋, 幸助 ; 荒井, 徳幸
概要:
application/pdf<br />Journal Article<br />This paper proposes an actuator in the magnetic levitation system using a permanent magnet and an electromagnet. In this system, the gravity force of the masses is supported by a strong permanent
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magnet in which two identical poles face each other. The vibration due to external disturbances is controled by use of the electromagnet by changing magnetic fluxes of one of the permanent magnets. The analytical expressions for obtaining the levitation force, spring constant and the control force versus the electric current in the electromagnet were derived using the equation of the electromagnetic theory. Numerical simulations under the control using the optimal regulator for the magnetically levitated boby were carried out. To verify the present theoretical results, experimantal results were also obtained.
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| 21.
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永井, 健一
概要:
application/pdf<br />Journal Article<br />This paper presents a method for the suppression of large amplitude bending vibrations of a clamped curved beam by controllable forces in an elastic support. The elastic support force, acting on
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the middle span of the beam, is generated by the electromagnet. Applying the Galerkin method to the basic equations, non-linear coupled differential equations are reduced: the forced responses are calculated utilizing the harmonic balance method. From the analytical results, it is shown that natural frequencies are easily shifted away from the resonant frequency by the changeable support forces. Experimental work has also been carried out to clarify the validity of this control method. It is found that the experimental results are good agreement with the analytical ones.
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長屋, 幸助 ; 佐藤, 浩 ; 中村, 信章 ; 武田, 定彦 ; 永井, 健一 ; 井開, 重男 ; 孫, 健利
概要:
application/pdf<br />Journal Article<br />Thi paper describes a method of active vibration control for passing through critical speeds of a rotating shaft using electro-magnetic clutches. In this method the vibration of the shaft due to
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whirling is controlled by means of on and off electric current controls of the electro-magnetic clutches which support the shaft under the on control, The principle of this method is to change the eigen-frequencies of the shaft by adding or losing the supports during shaft rotation. To verify the present method, this paper provides a model of a rotating shaft system with an electro-magnetic clutch, and examines the results analytically and experimentally.
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長屋, 幸助 ; 武田, 定彦 ; 津久井, 洋一 ; 熊井戸, 孝勇
概要:
application/pdf<br />Journal Article<br />This paper presents a method for passing critical speeds of a rotating shaft by use of support springs made of memory metals. In this method the vibrations of the shaft due to whirlings are
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controlled by use of the on (heating) and off (cooling) heat control of the memory metals which support the bearings. In the analysis, the exact solution is obtained on the problem of a multi-span shaft carrying a disc. Numerical calculations have been carried out for some important problems and experimental tests have also been carried out to verify the present control method and the theoretical results.
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小島, 宏行 ; 新山, 文彦 ; 長屋, 幸助 ; 永井, 克巳
概要:
application/pdf<br />Journal Article<br />本報は, 希土類磁石を用いた電動リニアアクチュエータと速度センサに制御回路を付与して構成した速度フィードバック形電磁ダンパを試作し, これを調和加振力が作用
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しているはり状構造物に取付けて振動制御の実験を行うとともに, はり状構造物と制御系との両方を考慮し, ベルヌーイ・オイラーのはり理論を用いて系の応答を厳密に解析したものである. また制御系のゲインなどの因子が制御効果や系の応答に及ぼす影響を解明した.
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小島, 宏行 ; 新山, 文彦 ; 長屋, 幸助 ; 永井, 克巳
概要:
application/pdf<br />Journal Article<br />本報は, 衝撃力が作用するはり状構造物の振動制御の実験を, 前報で試作した速度フィードバック形電磁ダンパを用いて行うとともに, はり形の振動変位ならびに制御
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系の電流の衝撃応答解を, ラプラス変換法およびベルヌーイ・オイラーのはり理論を用いて厳密に導いたものである. なお衝撃力として, マイクロコンピュータと電動リニアアクチュエータによる電磁力を用いた. さらに振動制御の効果や安定性などについて詳細に調べた.
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