Abstract:

Aiming to the problem of the incomplete navigation information and constraint of line-of-sight angle during the target approaching phase for a tethered space robot, the dynamic model of the tethered space robot is established. Considering the constraints of the control inputs and the field of view of the gripper, the optimal approaching trajectory of the tethered space robot to the target is designed using the Gaussian pseudospectral method. A closed loop optimal control scheme is presented without using the relative distance between the gripper and the target. The simulation results of the closed-loop control scheme show that the proposed scheme can overcome the influence of the constraint of line-of-sight angle and realize the accurate position and attitude tracking of the optimal trajectory.

Key words:  Tethered space robot, Approaching target, Gaussian pseudospectral method, Optimal control method