Optimal control of approaching target for tethered space robot based on non-singular terminal sliding mode method

摘要

In the tethered space robot approaching phase, the tether can provide attitude control torque and orbit control force, it can reduce the fuel consumption of the gripper, but there is operation coupling for the tether is not always pass through the centroid of the gripper. And the field of view of the camera is limited, the tracking error of attitude and position can make the target deviate from the camera view field Aiming to above problems, a position and attitude coordinated control scheme based on non-singular terminal sliding mode method is designed for the approaching task. The dynamic model of tethered space robot based on lumped mass model and elastic rod model are established, respectively. Combining the dynamic model of tethered space robot based on elastic rod model with the relative motion model of the target, a Gaussian pseudo spectral motion planning model is established, the planning model takes into account the constraints of control input and the field of view of gripper. Solving the programming model, the optimal approaching trajectory of the tethered space robot is obtained. Then, a trajectory tracking controller is designed based on non-singular terminal sliding mode method. The simulation results show that the proposed control scheme can realize the accurate position and attitude tracking of the optimal trajectory. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.