协作机械臂碰撞环境下的安全控制

Safety control of cooperative manipulators in collision environment

中文关键词  人机协作  干扰观测器  滑模控制  自适应导纳控制

英文关键词  human-robot cooperation  interference observer  sliding mode control  adaptive admittance control

中文摘要

      针对人机协作过程中机械臂末端与操作者之间可能存在物理碰撞的问题, 本文提出一种基于自适应导纳和滑模控制的机械臂安全控制方法. 首先, 采用基于广义动量的干扰观测器估计机械臂各关节和末端执行器上的干扰力. 然后, 设计一个双环控制结构, 内环是基于干扰观测的双幂次趋近律滑模轨迹跟踪控制器, 用以克服外界干扰的影响, 达到期望的轨迹跟踪精度; 外环是自适应导纳控制器, 依据碰撞外力的大小和方向更新期望轨迹, 以保证机械臂碰撞发生时的柔顺性和碰撞解除后迅速恢复工作状态的能力. 最后, 对所提算法进行仿真和实验验证. 实验结果表明, 协作机械臂碰撞环境下的安全控制算法能保证人机协作的安全性和机械臂工作的连续性, 满足人机协作过程中的工作需求

英文摘要

      In view of the possible physical collision between the end of the manipulator and the operator in the process of human-robot cooperation, a safety control method of the manipulator is proposed based on the adaptive admittance and sliding mode control. Firstly, the interference observer based on the generalized momentum is used to estimate the interference force of each joint and end effector. Then, a double-loop control structure is designed. The inner loop is a sliding mode trajectory tracking controller based on the double-power reaching law and interference observation, which can overcome the influence of external interference and achieve desired trajectory tracking accuracy. The outer loop is an adaptive admittance controller, which updates the desired trajectory according to the magnitude and direction of the external force caused by collision, so as to ensure the flexibility of manipulators in collision environment and the ability to quickly resume its working state after the collision is resolved. Finally, the proposed algorithm is verified by simulation and experiments. The experimental results show that the safety control algorithm can ensure the safety of human-robot collaboration and the continuity of manipulators’ work, which meets the work requirements in the process of human-robot collaboration.