空间机器人双臂捕获航天器操作的无源自抗扰避撞从顺控制

Passivity Active Disturbance Rejection Collision Avoidance Compliant Control of Dual-arm Space Robot Capture Spacecraft

针对空间机器人双臂捕获非合作航天器过程中避免关节受冲击破坏的避撞从顺控制问题,在机械臂与关节电机之间设计了一种由旋转型串联弹性执行器(RSEA)构成的弹簧缓冲装置.通过缓冲弹簧变形来吸收捕获碰撞阶段产生的冲击能量,并采用合理的避撞从顺控制策略,保证镇定运动阶段关节受到的冲击力矩限制在安全范围内.应用拉格朗日方法及牛顿-欧拉法,分别建立捕获前双臂空间机器人开环系统及航天器系统动力学模型;结合冲量定理、闭链系统位置及运动学关系,得到捕获操作后两者所构成闭链混合体系统的动力学模型.为实现失稳混合体系统的镇定,提出了一种基于无源性理论的自抗扰避撞从顺控制方案.此外,运用最小权值范数法对机械臂各关节力矩进行分配,保证了各臂协调操作.通过数值模拟,验证了缓冲装置的抗冲击性能及控制策略的有效性.

The collision avoidance compliant control of dual-arm space robot on-orbit capture of non-cooperative spacecraft is studied.For this reason,a spring class buffer device composed of Rotary Series Elastic Actuator(RSEA)is mounted between the joint motor and manipulator,which functions are as follows.First,the deformation of its buffer spring can absorb the impact energy of the contact and collision phase.Second,combining the reasonable collision avoidance compliant control scheme to ensure that the impact torque of the joints during motion stabilization phase can be limited to a safe range.The dynamic models of the open chain dual-arm space robot with RSEA and the spacecraft before capture are obtained by using the Lagrange approach and Newton-Euler method.Then,based on the impulse theorem,the geometrical and kinematic conditions of closed chain,the integrated dynamic model of the hybrid system is derived.Finally,considering the postcapture unstable closed-chain hybrid system which is caused by the impact effect,a passivity active disturbance rejection collision avoidance compliant control is proposed for the stabilization control.In addition,the joint torques are distributed by the minimum weighted norm theory to ensure the coordinated operation of the manipulators.Numerical simulation verifies the impact resistance performance of the buffer device and the effectiveness of the proposed strategy.