机械臂在未知环境下基于力/位/阻抗的多交互控制

Multi-Interaction Control for Manipulators in Unknown Environments Based on Hybrid Position-Impedance-Force Control

  • 摘要: 针对人-机械臂交互的不确定性以及环境的未知性,提出了一种基于速度控制的方法来研究人、机械臂和环境三者之间的交互问题.首先通过在机械臂末端安装2个6维力传感器来实现交互力的检测,并在末端工具连接处增加单自由度柔性环节来实现机械臂的柔顺性.其次,基于iTaSC(instantaneous task specification using constraints)方法对机械臂与工具系统的柔顺度建模,在输出空间中建立起速度/位置与力的关系,实现机械臂与环境之间接触力的控制,通过刚度矩阵实现人对机械臂的拖动控制.另外结合力/位/阻抗混合控制方法实现了在安全区域约束下人拖动机械臂来完成一系列基于位置/力的任务,并与未知环境之间达到一个良好的交互.最后将提出的算法在UR5机械臂上进行轮廓跟踪任务的验证,实验结果表明该方法能达到一个较好的交互控制效果.

     

    Abstract: For the uncertainty of human-manipulator interaction and the unknown environment, a velocity control based scheme is developed to study the interaction among the human, the manipulator and the environment. Firstly, two 6-dimension force sensors are mounted at the end-effector of the manipulator to measure the interaction forces, and a compliant link with single DOF (degree of freedom) is added at the tool connection to achieve the compliance of the manipulator. Secondly, the compliance of the manipulator and the tool is modeled based on iTaSC (instantaneous task specification using constraints), so as to relate forces and position/velocities in the output space and realize the contact force control between the manipulator and the environment, and the stiffness matrix is adopted to drag the manipulator by an operator. Through the hybrid force-position-impedance control, the operator can drag the manipulator to complete a series of position/force tasks and interact with the unknown environment under the constraint of the safety area. Finally, the proposed algorithm is tested on a UR5 platform to complete the contour tracking task, which confirms that the proposed approach can implement good interaction control.

     

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