Multi-Objective Trajectory Optimization of Free-Floating Space Manipulator Using NSGA-II

Abstract

In this paper, a kind of multi-objective trajectory optimization method based on non-dominated sorting genetic algorithm II (NSGA-II) is proposed for free-floating space manipulator. The aim is to optimize the motion path of the space manipulator with joint angle constraints and joint velocity constraints. Firstly, the kinematics and dynamics model are built. Secondly, the 3-5-3 piecewise polynomial is selected as interpolation method for trajectory planning of joint space. Thirdly, three objective functions are established to simultaneously minimize execution time, energy consumption and jerk of the joints. At last, the objective functions are combined with the NSGA-II algorithm to get the Pareto optimal solution set. The effectiveness of the mentioned method is verified by simulations.

Trajectory Planning in Joint Space for a Pointing Mechanism Based on a Novel Hybrid Interpolation Algorithm and NSGA-II Algorithm

“…Ⅱ. By referring to other literatures and application experience [28,[34][35][36], the parameters of the NSGA-II algorithm are shown in Tab. Ⅲ.…”

“…It has been proven most effective in MOPs [32,33]. In addition, it is very popular in trajectory optimization [34][35][36]. Therefore, the proposed hybrid interpolation algorithm combined with the NSGA-Ⅱ algorithm is applied to the trajectory planning and optimization of a X-Y pointing mechanism.…”

Motion planning optimization of trajectory path of space manipulators

“…The linear velocity and angular velocity at the end of the manipulator can be obtained by differentiating equation (1), and the matrix form [9] where v e , v 0 represent the linear velocity of the end of the manipulator and the pedestal respectively, v e , v 0 represent the angular velocity of the end of the manipulator and the pedestal respectively, J 0 , J m represent the Jacobian matrix of the pedestal and the whole mechanical arm, u represents the joint angle matrix, E represents the unit matrix, and k i represents an expression of the Z-axis of the joint coordinate system relative to the inertial coordinate system. In this study, it is assumed that the space manipulator is in a free floating state while working, that is, the whole body maintains momentum conservation, and the dynamic equation of the manipulator can be obtained by combining equation 2:…”