Kinematic Modeling And Trajectory Planning Of Redundant Manipulator

The 7-DOF redundant manipulator on the inspection robot can be applied in various scenarios.After the inspection robot reaches the specified position,the manipulator can realize the function of flexible operation in a narrow space or delivering the probe to observe the complex space.The 7-DOF redundant manipulator increases the attitude degree of freedom of the manipulator under the premise of satisfying the end pose.Even if the manipulator has some faults or is disturbed by the outside world,it can still complete the task by adjusting the redundant degree of freedom,thereby improving the fault tolerance performance and avoiding singular positions and joint limits during work.In this paper,the inverse kinematics,trajectory planning and obstacle avoidance path planning of the 7-DOF redundant manipulator are studied.The main contents are as follows:(1)The kinematics of 7-DOF redundant manipulator is analyzed.According to the mathematical relationship,the forward kinematics formula of the redundant manipulator is derived.The kinematics model of the redundant manipulator is established by D-H method,and the working space of the redundant manipulator is described by Monte Carlo method.(2)An Improved Sparrow Search Algorithm(ISSA)is proposed which aim at the inverse kinematics problem of 7-DOF redundant manipulator.The algorithm uses the Halton sequence to initialize the population,combines the Butterfly Optimization Algorithm(BOA)to improve the global search ability of the algorithm,and finally performs Gaussian mutation to avoid local optimal solutions.The simulation results show that compared with the SSA algorithm,the pose error and standard deviation of ISSA algorithm are reduced by 98.63%and 84.29% respectively.,indicating that the ISSA algorithm is superior to the SSA algorithm in the accuracy and stability of the inverse kinematics solution.(3)An Adaptive Particle Swarm Optimization Algorithm(APSO)is proposed for the 3-5-3 mixed polynomial time optimal trajectory planning problem of 7-DOF redundant manipulator.The algorithm uses a good point set to initialize the population,and uses adaptive weights and dynamic learning factors to improve the search ability of the algorithm.The simulation results show that the optimized running time is shortened by 27.56%,which proves the effectiveness of the method.(4)Aiming at the obstacle avoidance problem of 7-DOF redundant manipulator,the redundant manipulator link is enveloped by cylindrical space,and the obstacle is enveloped by spherical space.In the workspace,the RRT algorithm and the RRT-Connect algorithm are used to avoid obstacles.The simulation results show that the RRT-Connect algorithm is superior to the RRT algorithm in terms of running time and path length.The test bench is built in the actual environment to verify the obstacle avoidance performance of the RRT-Connect algorithm.The redundant manipulator can quickly avoid obstacles and reach the target position.