关键词: 漂浮基空间机器人, 柔性关节, 柔性臂, 奇异摄动, 滑模

Abstract:

A dynamics modeling, motion controller design and joint-link double flexible vibration suppression problem of free-floating flexible-link and flexible-joint space robot were discussed. The dynamic equations of the system were established according to system's momentum conservation, angular momentum conservation and Lagrange-assumed mode method. Based on singular perturbation method, the system was decomposed into three mutual independent subsystems: a “rigid-joint and rigid-link” slow subsystem represented the rigid-joint and rigid-link system's rigid motion, a “flexible-joint and rigid-link” fast subsystem represented the system's elastic vibration caused by flexible-joint and a “rigid-joint and flexible-link” fast subsystem represented the system's elastic vibration caused by flexible-link. Then three controllers were designed for the three subsystems respectively. A nonlinear sliding mode controller was designed to realize the asymptotic tracking of the system's motion trajectory. A feedback controller was used to suppress the flexible vibration caused by flexible-joint based on the velocity difference between the link and the motor. A linear quadric regulator was used to suppress the flexible vibration caused by flexible-link. Therefore, the system's total controller was a composite of the three controllers. The simulation proves the proposed compound controller can guarantee the control system's accuracy and suppress the elastic vibration caused by flexible-joint and flexible-link effectively.

Key words: free-floating space robot, flexible-joint, flexible-link, singular perturbation, sliding mode