Fault-Tolerant Prescribed Performance Control of Cascade Nonlinear Systems With Sensor Faults and Unknown Dynamics

This study is dealt with the tracking control problem for the cascade strict-feedback systems under sensor faults and unknown dynamics. Both multiplicative and additive sensor faults are taken into account, with unknown bounds. Moreover, the commonly involved growth condition, the global Lipschitz condition and the parametric uncertain form for the uncertainties induced by internal dynamics are dismissed. They render the existing solutions infeasible. To cope with these challenges, a fault-tolerant prescribed performance control (PPC) approach is devised in this article. It achieves reference tracking with the predefined accuracy and settling time, despite the multiple sensor faults, the totally unknown nonlinearities, and the unmatched disturbances. It also dispenses with parameter adaption, function approximation, fault estimation, derivative calculation, and disturbance estimation, thus with a control simplicity. The verification of the aforementioned theoretical results is performed by a comparative experiment on a serial flexible link robotic manipulator.