Sliding Mode Control of Cable‐Driven Redundancy Parallel Robot with 6 DOF Based on Cable‐Length Sensor Feedback

Abstract

The sliding mode control of the cable‐driven redundancy parallel robot with six degrees of freedom is studied based on the cable‐length sensor feedback. Under the control scheme of task space coordinates, the cable length obtained by the cable‐length sensor is used to solve the forward kinematics of the cable‐driven redundancy parallel robot in real‐time, which is treated as the feedback for the control system. First, the method of forward kinematics of the cable‐driven redundancy parallel robot is proposed based on the tetrahedron method and Levenberg‐Marquardt method. Then, an iterative initial value estimation method for the Levenberg‐Marquardt method is proposed. Second, the sliding mode control method based on the exponential approach law is used to control the effector of the robot, and the influence of the sliding mode parameters on control performance is simulated. Finally, a six‐degree‐of‐freedom position tracking experiment is carried out on the principle prototype of the cable‐driven redundancy parallel robot. The experimental results show that the robot can accurately track the desired position in six directions, which indicates that the control method based on the cable‐length sensor feedback for the cable‐driven redundancy parallel robot is effective and feasible.