Adaptive Fault-Tolerant Control for Free-Floating Space Manipulator with Parameter Uncertainties

In this paper, an adaptive fault-tolerant control scheme is proposed for the free-floating space manipulator (FFSM) with unknown parameters of dynamic model and actuator faults. In control design for the FFSM, because of unknown loads or tools attached to the manipulator, the structure parameters of the FFSM will change, which leads to uncertainties in the FFSM dynamic model. Meanwhile the space manipulator is prone to failure in the long-term operation. For the above two issues, we propose a control method based on direct adaptation of uncertainties with linear parametrization of dynamic model. Further, time-varying actuator faults are handled by estimating the bounds of unknown parameters in the fault model. Simulation is carried out to demonstrate the validity of the proposed method.