Application Of Improved Sparrow Search Algorithm In Kinematics And Trajectory Planning Of Redundant Manipulator

The inverse kinematics of redundant manipulators has always been a hot research topic.Redundant manipulators are more flexible than 6-DOF manipulators.However,the inverse kinematics of redundant manipulator has infinite sets of inverse kinematics solutions,and it is very difficult to find the inverse kinematics solutions,so the inverse kinematics of redundant manipulator has research significance.The inverse kinematics of manipulator is the basis of trajectory planning,which is the prerequisite for the smooth operation of manipulator.In order to improve the working efficiency of manipulator,trajectory planning has become a research hot spot.This thesis mainly takes 7-DOF redundant manipulator as the research object.Based on the improved sparrow search algorithm,inverse kinematics and trajectory planning of redundant manipulator are studied.Simulation experiments are established to verify the feasibility of the improved algorithm.The details are as follows:(1)Forward kinematics modeling of redundant manipulator was carried out by standard D-H parameter method;The functional expressions of each joint of the redundant manipulator are derived by analytical method.Finally,the workspace of the redundant manipulator is analyzed,and the scatter graphs under different coordinates are obtained;(2)Based on the chaotic Sparrow search algorithm(CSSA)global search ability,search speed and other good characteristics.A chaotic sparrow search algorithm was proposed to analyze the inverse kinematics of redundant manipulator,and compared with the Sparrow search algorithm(SSA).Taking pose error as fitness function,simulation experiments were established to verify the feasibility of the method.The results show that the convergence accuracy and stability of the chaotic sparrow search algorithm are improved by 1 order of magnitude compared with the sparrow search algorithm.However,from the perspective of practical engineering application,the chaotic sparrow search algorithm is unstable in many simulation experiments,so it is necessary to further study the chaotic sparrow search algorithm;(3)Aiming at the deficiency of CSSA,an improved chaotic sparrow search algorithm(ACSSA)is proposed.Four benchmark test functions were used to verify the characteristics of ACSSA.ACSSA was applied to solve the inverse kinematics of redundant manipulator.It was verified in two working conditions: point-to-point motion and continuous trajectory motion.The results show that ACSSA has advantages in convergence accuracy,convergence speed and stability.In order to verify the versatility of ACSSA in solving the inverse kinematics of the manipulator,ACSSA was applied to solve the inverse kinematics of the general 7-DOF redundant manipulator.The simulation results were basically consistent with those of the 7-DOF redundant manipulator satisfying the Pieper criterion;(4)The improved chaotic sparrow search algorithm is applied to the time optimal trajectory planning of redundant manipulator.The kinematic constraints of the redundant manipulator were carried out to optimize the "3-5-3" polynomial interpolation time,and simulation experiments were established to generate the curves of angular displacement,angular velocity and angular acceleration of each joint in the process of motion with time.The results show that the trajectory running time is shortened by 28%,and the variation curves of each joint are stable and continuous without mutation.