冗余度机械臂初始位置误差容错研究

Research on Fault Tolerance of Initial Position Error for Redundant Manipulator

针对冗余度机械臂在执行跟踪任务时,末端执行器的实际初始位置与期望初始位置之间存在误差的情况,探讨了一种基于伪逆的控制方法。在加速度层求解机械臂冗余度解析问题,并引入关节速度/位置的反馈信息,及时调节关节加速度,以减小末端执行器的实时位置误差。通过加速度连续函数,保证关节加速度的连续。若初始位置误差较大,通过位置调整函数,使关节加速度在运动过程中合乎实际情况。平面三连杆机械臂跟踪圆形轨迹以及PUMA560机械臂在三维空间跟踪心形轨迹的MATLAB仿真实验,验证了末端执行器能在较短的时间内跟踪期望轨迹,并以较高的精度完成任务。

In view of the error between the actual initial position of the end effector and the expected initial position when a redundant manipulator performs tracking tasks,a control method based on pseudoinverse is discussed.The redundancy analysis problem of the manipulator is solved at joint-acceleration level,and the feedback information of velocity/position of joints is introduced to adjust the joint-acceleration in time,thus the real-time position error of the end effector is reduced.The continuity of joint-acceleration can be ensured by the acceleration-continuity function.If the initial position error is large,the position adjustment function ensures that the joint-acceleration of the manipulator accords with the actual situation during the movement process.MATLAB simulation experiments of planar three-link manipulator tracking circle trajectory and PUMA560 manipulator tracking heart-shaped trajectory in three-dimensional space show that the end effector can keep up with the desired trajectory in a short time,and successfully complete the task with high accuracy.