Capturing the Target for a Tethered Space Robot Using Robust Adaptive Controller

Aimed at the problem of stabilization for a tethered space robot (TSR) capturing a target, a position-based impedance control is presented based on the model of a tethered space robot system. For the problem of model uncertainty of the tethered space robot system, an artificial neutral network (ANN) is used to estimate and compensate for the uncertainty, and a robust term is designed to repress the interference of tether and the effect of the estimation deviation by the ANN. Then a robust and adaptive controller for the TSR capturing a target is designed, and the stabilization of the controller is demonstrated. For the purpose of comparison, a simulation for an adaptive controller without the robust term is made, and the result shows that the controller designed in this paper can guarantee the stabilization during the TSR capturing a target. Compared to the adaptive controller without the robust term, the robust adaptive controller can compensate for the uncertainty effectively, with smaller overshoot, less convergence time, and higher control accuracy during the control process.