Abstract:

A joint torque optimization method for space manipulators considering the motion in-orbit reliability is presented. Firstly, the point-to-point transfer task within the operating space is converted from Cartesian space into joint space. Each joint variable is parameterized by seven-order polynomial interpolation, and the optimal control parameters of particle swarm optimization (PSO) are obtained. Different from other traditional path planning methods, the objective function of PSO is to minimize the sum of mean value of each joint torque for the manipulator. Finally, PSO is used to optimize the motion path of space manipulator by using the objective function and the corresponding optimal control parameters, and the motion path which has a minimum sum of mean value of each joint torque is obtained. Simulation results demonstrate that, compared with the traditional path planning method and the joint torque optimization method which use the minimal 2-norm of joint torque as objective function, the mean value of the joint torque for the redundant manipulator is decreased by 33.57% and 10.47% respectively by using the proposed method, and the largest value of joint torque is decreased by 43.25% and 6.19% respectively.

Key words: Redundant space manipulator, Joint torque optimization, Minimum sum of mean value of joint torque, Particle swarm optimization