On Design And Motion Planning Of A Cable-driven Hyper-redundant Manipulator

Due to the characteristics of the large length-diameter ratio,the sufficient degrees of freedom and the high flexibility,the hyper-redundant manipulators are of great application value in the narrow and dangerous environment in the fields of aerospace manufacturing and nuclear power equipment maintenance.This research successfully developed a rope-driven redundant manipulator with 24 degrees of freedom,established the kinematics model and studied the relevant motion planning techniques.Some experiments were carried out on the experimental platform,and the motion of passing through the confined space was achieved.To meet the requirement of deep cavity operation,the performance criteria of the manipulator were determined,and a modular and lightweight design was proposed to develop a hyper-redundant manipulator composed of sleeves,joints and ropes.The manipulator used a new type of universal joint,which was light,flexible and easy-to-assemble.The hollow structure of the manipulator also enabled itself to be equipped with various detection or execution devices.The mechanical characteristics of the manipulator were analyzed using ANSYS.The results showed that the mechanical arm met the requirements of strength and stiffness.Based on the homogeneous coordinate transformation,the kinematic model of the manipulator's task space,joint space and actuation space was established.This research used Recurdyn to analyze the transient force of the two-articulated manipulator with ropes,summed up the characteristics of the wire rope tension,and obtained the relationship between the load and wire rope tension.In this paper,the motion planning techniques of the manipulator was studied,including the interpolation motion in the joint space,the trajectory tracking in the mission space and obstacle avoidance using artificial potential field method.To enhance the ability of deep cavity detection,a path following motion was developed by solving the nonlinear equation numerically.And the relationship between the accuracy of the equation and the path following error was analyzed.In view of the low efficiency of the numerical solutions of the nonlinear equations,a path following motion was proposed using iteratively sequential searching method and a linear interpolation method based on the discrete path curve.The performance of the algorithm was evaluated from three aspects: the position accuracy,the movement smoothness and the algorithm efficiency,and the result validated the feasibility and high efficiency of the algorithm.The experimental platform was built,and the terminal load test,the deep cavity detection,the task space trajectory following and path following experiment were carried out.The experimental results demonstrated the excellent performance of the manipulator and verified the rationality and effectiveness of the design and motion planning of the hyper-redundant manipulator.