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研究了双臂空间机器人系统捕获目标时发生碰撞的冲击效应及之后形成的闭链系统的稳定控制问题。针对具有漂浮基的空间机器人系统及目标系统,分别采用拉格朗日第二类方程及牛顿欧拉法分别建立其动力学模型。在双臂空间机器人捕获目标的过程中,利用力的传递关系及运动几何关系,分析了两者的瞬间碰撞冲击效应。对于两者接触后形成翻滚的联合体系统,结合闭环约束条件及总动量守恒原则,获得了闭链系统动力学方程;并设计了滑模变结构控制方案,以完成镇定运动控制。考虑到空间机器人闭链系统存在控制器冗余的情况,运用最小权值范数法,均衡分配各关节力矩。最后采用数值仿真实验模拟了碰撞冲击效应及镇定过程,并验证了上述控制方案的有效性。
The impact effect of the collision when the dual-arm space robot system catches the target and the stability control problem of the closed-chain system formed afterwards are studied. For the space-based robotic system with floating base and the target system, the dynamic model of the space-borne robot system and the target system are respectively established by Lagrange’s second-type equation and Newton-Euler method. In the process of capturing a target by a two-arm space robot, the instantaneous collision impact effect between the two is analyzed by using the transmission relation of the force and the geometric relationship of the movement. The kinematic equations of the closed-chain system were obtained by combining the closed-loop constraints and the principle of total momentum conservation. The control scheme of sliding mode variable structure was designed to complete the stabilization motion control. Considering the redundancy of controller in the closed-chain system of space robot, the method of minimum weight norm is adopted to distribute the joint moments evenly. Finally, the numerical simulation experiment was used to simulate the impact impact and the stabilization process, and the effectiveness of the above control scheme was verified.