空间机械臂在轨维修的视觉伺服操控策略

Visual Servoing Control Strategy for On-Orbit Servicing ofSpace Manipulator System

  • 摘要: 首先分析了空间机械臂/机械手系统在轨旋拧螺钉任务的尺寸链误差.为修正微重力环境和机械臂、模拟维修单机在轨安装导致的位姿偏差,特别是消除机械手抓取电动工具导致的随机误差影响,提出了航天员在轨标定电动工具位姿/全局相机测量电动工具位姿并引入机械臂进行视觉伺服的控制策略.设计了视觉伺服控制器,给出了该控制算法的收敛证明和稳定性分析.通过在轨实施,该策略实现了机械臂/机械手系统拧松螺钉时位姿误差不超过3 mm/2°的任务要求.

     

    Abstract: Aiming at the space manipulator/dexterous hand system screwing bolts on-orbit, the dimension chain errors of the system are analyzed firstly. To correct position and pose errors caused by zero-gravity and on-orbit assembly of manipulator and simulated orbital replacable unit, especially to eliminate the random errors caused by the dexterous hand grabbing an electric tool, a visual servoing control strategy is proposed. In the proposed strategy, the position and posture of the electric tool are measured by global cameras after astronauts calibrating its exact operating position and posture, and the manipulator is introduced into visual servo control. A visual servoing controller is designed, and the convergence proof and stability analysis of the control algorithm are given. In on-orbit implementation of bolt-screwing task of the manipulator, the requirement of position and pose errors less than 3 mm/2° is achieved.

     

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