パワーアシスト装置の研究 : 第1報,重力負荷と動的負荷に異なるアシスト比を設定する制御法の提案

This paper proposes a control method for the power assist system which is used to attenuate the load force. In the power assist system, selecting suitable power assist ratios is important. The power assist ratio must be selected with consideration of the maximum torque of actuators used in the system. When the system has an excessively large ratio, actuator saturation occurs which causes the lack of maneuverability and stability. To avoid such saturation problems, a control method in which the gravity load is assisted with a ratio different from one for the dynamic load is proposed. The gravity load applies to the operator every time a load is supported. The dynamic load applies to the operator only when the operator moves the load. With this consideration in mind, the method proposes that the ratio for the dynamic load should be selected considering the remaining actuator torque usable after the ratio for the gravity load is determined considering the operator's capability. The control method is formulated for a single-axis power assist system and the effectiveness of the method is confirmed by experiments.