基于微分同胚映射动态系统的接触任务运动规划与控制

Motion Planning and Control of Contact Task Based on Diffeomorphic Mapping Dynamical Systems

  • 摘要: 为解决目前机器人接触任务中时间相关的运动规划与控制方法抗扰动性弱的问题,提出了基于微分同胚映射动态系统的运动规划和控制方法。首先,采用动觉示教的方式在搭建的实验平台上采集人工完成接触任务时的位置和力数据,并建立基于微分同胚映射的动态系统。然后,将人工扰动条件下的接触任务分解为接触作业、人工扰动下运动和自由空间运动3个状态,并针对各个状态分别设计基于动态系统的力和姿态控制调节项。最后,分别进行无人工扰动和有人工扰动实验,同时与离线控制方法比较力控制效果。实验结果表明:当机器人从示教轨迹起点开始运动,10次重复实验的运动轨迹相比于示教轨迹位置和姿态的最大误差分别小于0.008 m和1.01 ^\circ ,力均方根误差的平均值为0.86 N,相比于离线控制方法略大;从自由空间任意位置出发,机器人都可以进入接触空间执行接触任务;当机器人在作业过程中出现人工扰动时,机器人可根据人的意图运动,且在扰动消除之后恢复作业且力均方根误差值与无人工扰动时的结果接近。实验结果充分验证了本文方法的有效性,实现了在扰动下接触任务的运动规划与控制,且具有较强的抗扰动性。

     

    Abstract: The existing time-dependent motion planning and control methods show a poor anti-disturbance ability when the robot performs contact tasks. This paper proposes a motion planning and control method based on a diffeomorphic mapping dynamical system to solve the problem. Firstly, the position and force data of human executing contact tasks are collected on the established experiment platform by kinesthetic teaching, and a dynamical system based on diffeomorphic mapping is developed. Then, the contact task with human disturbances is decomposed into three states: executing the contact task, moving under human disturbances, and moving in free space. In addition, adjustment terms for force and orientation control are designed for each state based on the dynamical system. Finally, experiments are conducted in which the robot performs the contact task with and without human disturbances. The results of force control based on the proposed method are compared with the results of the offline control method. In comparison with the demonstration trajectory, the maximum position and orientation errors in the 10 repeated experiments without human disturbances are less than 0.008 m and 1.01°, respectively. In addition, the average value of the root mean square error (RMSE) of force is 0.86 N, which is slightly larger than the offline control method. The robot can reach the contact space to perform the contact tasks from any position in free space. When a disturbance occurs during the operation process, the robot will follow the instructions of the operator and resume the tasks after the disturbance with a force RMSE similar to the result without human disturbances. The experimental results confirm the effectiveness of the proposed approach, which realizes motion planning and control for performing contact tasks under human disturbances while ensuring a good anti-disturbance ability.

     

/

返回文章
返回