Trajectory Planning of Space Robot System for Target Berthing and Reorientation after Capturing

Abstract

A typical servicing operation in space mainly includes three phases: capturing the target, berthing and docking the target, and repairing the target. The attitude of a satellite usually changes after the capturing, because the control system is turned off during this phase for safety reasons. In this paper, a method is proposed to achieve the berthing of the target and re-orientating the satellite attitude at the same time, both by involving manipulator motion only. Firstly, the constraints on the manipulator and the objective function are defined according to the planning problem. Then the joint trajectory is parameterized by sinusoidal function, whose argument is the polynomial. Finally, Genetic Algorithm is used to search for the global optimal resolution of the parameters. When the parameters are found, each joint trajectory can be determined. This planned trajectory is smooth and more applicable for the control of the free-floating robotic system. Our proposed method is verified by simulation.