An Effective Approach Control Scheme for the Tethered Space Robot System

Abstract

The tethered space robot system (TSR), which is composed of a platform, a gripper and a space tether, has great potential in future space missions. Given the relative motion among the platform, tether, gripper and the target, an integrated approach model is derived. Then, a novel coordinated approach control scheme is presented, in which the tether tension, thrusters and the reaction wheel are all utilized. It contains the open-loop trajectory optimization, the feedback trajectory control and attitude control. The numerical simulation results show that the rendezvous between TSR and the target can be realized by the proposed coordinated control scheme, and the propellant consumption is efficiently reduced. Moreover, the control scheme performs well in the presence of the initial state's perturbations, actuator characteristics and sensor errors.

Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras

“…A variable structure control strategy was presented by Fang [ 14 ], where a neural network controller is used as the dynamic compensator. Huang et al studied the tethered space robot (TSR), and presented several trajectory planning and control methods [ 15 , 16 , 17 ]. To stabilize the TSR during capture impact with target, Huang derived the impact dynamic model for target capturing and an adaptive robust controller was designed accordingly [ 18 ].…”

In-plane adaptive retrieval control for a noncooperative target by tethered space robots

“…1 Using tether to replace rigid arms, the capture distance of TSR can reach several hundred meters long and the terminal maneuver of platform is unnecessary, which greatly improves the security of the platform and reduces the propellant consumption. 2 However, many problems may arise in the flight control of TSR for the space tether.…”

“…23 Considering the motion of the platform, an approach control scheme is studied by Meng and Huang, in which the tether tension, thrusters, and the reaction wheel are all utilized. 2 An attitude and orbit coupling controller is also proposed by Huang et al, in which an optimal open-loop controller is designed based on the hp-adaptive pseudospectral method to minimize the fuel consumption and a classical proportional-derivative (PD) controller is designed to generate the error corrections. 24 However, in the aforementioned literatures, dynamic parameters, including mass and moment of inertia, are assumed to be certain and known.…”