Coordinated control method of space tethered robot for approaching targets

In order to save the thruster fuel of an end effector for a space tethered robot in the process of approaching a target satellite, a coordinated control method is proposed in the paper which utilizes the thruster, the reaction wheel and the space tether. First, this method calculates the ideal orbit control force of the end effector for the approaching target by linear quadratic regulator (LQR) algorithm. Then this force is allocated to the thrusters and space tether through optimization using a simulated annealing algorithm. Simultaneously, the attitude interferential torque of the space tether is compensated through a reaction wheel using the time delay algorithm. The simulation results show that the coordinated control method can significantly save thruster fuel of the end effector, and it also restrains attitude disturbance produced by the coordinated control force of the space tether and maintains relative attitude stability of the end effector.