Trajectory planning of a redundant space manipulator based on improved hybrid PSO algorithm

Abstract

The rapid development of aerospace technology means that the roles of space robots are becoming important. In order to reduce fuel consumption and successfully accomplish on-orbit service tasks, the base attitude disturbance should be as small as possible. When the particle swarm optimization (PSO) algorithm based trajectory planning method is applied to solve the problem, it is falling into local optimum easily and obtaining the optimal solution hardly. To solve the issue, the improved hybrid PSO (IHPSO) algorithm based trajectory planning method in this paper for a redundant manipulator is presented. Firstly, a three-dimensional model of the spherical-round-spherical (S-R-S) redundant space manipulator, which has seven degrees of freedom, is designed by SolidWorks 2013. Secondly, a kinematics model is established through the Denavit-Hartenberg (D-H) parameter method. In order to prevent singularities appearing in the calculation process, the positive kinematics equation combined with the generalized Jacobian matrix are adopted to deduce the kinematic equations for the space manipulator. Thirdly, the 5-order sine function method is employed to describe the trajectory of joint angles. Finally, the unknown parameters of trajectory are solved optimally by the proposed IHPSO algorithm. The experimental results verify that the proposed IHPSO algorithm is more productive than the PSO algorithm and the linear decreasing weight PSO (Lin-WPSO) algorithm in solving the optimal parameters. The proposed IHPSO algorithm based trajectory planning method can plan a satisfying trajectory under minimizing base attitude disturbance for a redundant manipulator.