Abstract: Aiming at the problem of trajectory planning for the Free Floating Space Robot (FFSR), this paper proposes an FFSR trajectory planning method based on the kinodynamic RRT^* algorithm. The kinematics and dynamics model of the FFSR is first established with the pseudo linear system model reconstructed into the state space model and a weighted objective function designed considering both time and energy consumption of posture adjustment. Secondly, considering the obstacles between the initial and final positions of the manipulator, we propose a simplified obstacle avoidance method, formulating a two-level obstacle avoidance strategy for robotic arms and the manipulator to improve the collision detection efficiency. The kinodynamic RRT^* approach to the optimal trajectory is presented. Finally, to verify the effectiveness of the algorithm without generality loss, the 2-degree of freedom FFSR model is selected for numerical simulation. The classic RRT^* algorithm and Gauss pseudo-spectral method are used for comparison. The simulation results show that the method can generate feasible robot trajectories with fewer iterations.

Key words: free floating space robots, multi-objective planning, trajectory planning, kinodynamic RRT^*, obstacle avoidance