油圧と空気圧
Online ISSN : 2185-5285
Print ISSN : 0286-6900
ISSN-L : 0286-6900
28 巻, 2 号
選択された号の論文の4件中1~4を表示しています
  • 山本 耕治, 谷井 悟, 吉田 一人, 田中 和博
    1997 年 28 巻 2 号 p. 224-231
    発行日: 1997/03/15
    公開日: 2011/03/03
    ジャーナル フリー
    A monitoring camera, which is usually set on top of a mobile crane boom for the purpose of keeping safety and ease of operation, plays an important role as an another eye for the crane operator. Recently, the total length of a mobile crane has been increased much more as buildings become higher and a crane boom has been lightened so as to carry many loads faster at one time. As a result, the stiffness of the crane boom becomes low. These low stiffness and lengthening of the crane boom amplify a small oscillation which does appear in the conventional ones. The monitoring camera at the top of a crane boom often oscillates strongly making monitoring by the operator difficult. A new device for damping the oscillation of the monitoring camera is needed.
    In the present paper, we developed a new oil-damper to stabilize the oscillation and investigated its characteristics in simulation as well as by experiments. Simulation is based on the Bondgraphs method, which represents systems from the viewpoint of energy flow and is a very attractive method for simulating the dynamic behavior of systems composed of electric, hydraulic and mechanical components. The simulation results agree well with the experiments and the dynamical model has been established.
  • 第1報, 数値シミュレーションと実験的検討
    林 叡, 飯塚 祐二, 早瀬 敏幸, 飯村 〓郎
    1997 年 28 巻 2 号 p. 232-238
    発行日: 1997/03/15
    公開日: 2011/03/03
    ジャーナル フリー
    In this paper, the authors have derived a mathematical model describing the dynamics of a balanced piston type relief valve, which is represented by 11 ordinary differential equations and 3 difference equations depicting the dynamics of a supply and load pipeline which are assumed to be as lossless distributed parameter elements. The validity of the model has been confirmed by comparing the simulated results with experimental results. Furthermore, influences of the system parameters on the dynamic characteristics of a relief valve have been investigated by simulation of the proposed model.
  • 第2報, リリーフ弁の安定性
    林 叡, 飯塚 祐二, 飯村 〓郎, 早瀬 敏幸
    1997 年 28 巻 2 号 p. 239-244
    発行日: 1997/03/15
    公開日: 2011/03/03
    ジャーナル フリー
    In this paper, the authors have studied the stability of a balanced piston type relief valve on the basis of a mathematical model derived and confirmed to be valid qualitatively in the previous paper. It has been demonstrated that the stability of a relief valve can be easily analyzed by a method dividing the overall operating region into two parts by the cracking condition of the main valve. The analysis shows that the stability of a relief valve is subject to the stability of the pilot part.
  • 楊 清海, 川上 幸男, 河合 素直
    1997 年 28 巻 2 号 p. 245-251
    発行日: 1997/03/15
    公開日: 2011/03/03
    ジャーナル フリー
    This paper deals with the position control of a pneumatic actuator in which the mechanical friction is not negligible. In our system, the rod chamber pressure of the cylinder remains constant, and the head chamber pressure is controlled using two solenoid valves. The valves are under PWM mode control. A dynamic mathematical model of the system incorporating the PWM solenoid valve is established to simulate the system characteristics. It is shown that the nonlinear mechanical friction causes a stick-slip response in the system. To increase system performance, pressure feedback is formed to decrease the stick-slip and nonlinear friction compensation is implemented to reduce the steady-state error due to the friction. The friction compensation is realized by using the information of the mechanical friction in the system. Simulation and experimental analysis shows that the proposed control strategy is effective.
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