IJCAS

Control of nonlinear robotic systems suffering from actuator failure is a significant, yet challenging problem. In this paper, an observer-based fault-tolerant control method is proposed for robotic systems with external disturbances and modeling discrepancy. Technically, based on the state transform, an unknown input observer is designed to estimate the lumped unknown input. With the aid of the proposed observer, the estimate error is ensured to decay to zero within finite time. Subsequently, the estimated unknown input is utilized to compensate the compound unknown input of the faulty system. The analytical results proved that the tracking error of the closedloop system converges to zero in finite-time, even in the presence of actuator faults. Finally, simulation results are provided to demonstrate the effectiveness of the proposed scheme.

Keywords: Backstepping, fault-tolerant control, finite-time control, observer, robotic systems.