※一部利用できない機能があります
| 1.
論文 |
論文
|
長屋, 幸助 ; 湯澤, 秀人 ; 村上, 岩範
概要:
application/pdf<br />Journal Article<br />Since a commutator of the DC-motor is divided into a number of segments to have the torque in the circumference direction, the currents in the coils of the rotor vary and have alternative
…
waves during the rotor rotation even in a constant input voltage. The currents become sharp waves, so that they have high frequency component. This implies that the rotor shaft and the case of motor are excited electromagnetic forces with high frequency components. Since high frequency noises are loud when they are input to human ears, so that when high frequency vibrations are suppressed, noises become small. From the situation, this paper discusses a method of noise reduction of Dc Motor. In the method, the current waves are controlled to be sinusoidal waves. The method and the control algorithm are given. In order to validate the method, experimental tests are carried out. It is proven that our method is applicable to the motor noise control.
続きを見る
|
||||||
| 2.
論文 |
論文
|
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
…
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.
続きを見る
|
||||||
| 3.
論文 |
論文
|
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,
…
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.
続きを見る
|
||||||
| 4.
図書 |
図書
|
研究代表者 長屋幸助
|
||||||
| 5.
論文 |
論文
|
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
…
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.
続きを見る
|
||||||
| 6.
論文 |
論文
|
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.
…
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.
続きを見る
|
||||||
| 7.
論文 |
論文
|
藤沢, 延行 ; 中林, 貴光 ; 池本, 宏一郎 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />The active control of vortex shedding from a circular cylinder by rotary ocillations is studied experimentally using neural networks, which optimizes automatically the control parameters such as
…
the phase lag and the feedback coefficient. This optimization procedure is applied to find out an optimum position of reference probe to attenuate the vortex shedding effectively. The attenuation effect of vortex shedding under this control is investigated by measuring the velocity fluctuations in the cylinder wake and the unsteady pressure distributions over the cylinder surface. It is found that the drag and lift forces acting on the cylinder are reduced under the optimum reference control in comparison with the control under other reference positions as well as those of the stationary cylinder.
続きを見る
|
||||||
| 8.
論文 |
論文
|
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
…
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.
続きを見る
|
||||||
| 9.
論文 |
論文
|
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
…
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.
続きを見る
|
||||||
| 10.
論文 |
論文
|
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
…
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.
続きを見る
|
