|Asymptotic Estimation of State, Fault and Perturbation for Nonlinear Systems and Its Fault-tolerant Control Application
Jianglin Lan* and Ron Patton
International Journal of Control, Automation, and Systems, vol. 19, no. 3, pp.1175-1182, 2021
Abstract : This paper addresses the challenge of robust simultaneous estimation of state and actuator faults for Lipschitz nonlinear systems with unknown perturbations acting on both the state dynamics and output measurements. The existing methods enhance the estimation robustness by suppressing the perturbations or decoupling them under satisfaction of the matching condition. This work considers a total elimination of the perturbation effects through perturbation reconstruction. An adaptive sliding mode unknown input observer (ASMUIO) is developed to realize simultaneous asymptotic estimation of the state, faults and perturbations. It leverages a descriptor system reformulation of the original system by regarding partial perturbations as virtual state and the rest part as virtual faults. The proposed ASMUIO has feasibility guarantee and is solved via a linear matrix inequality (LMI) setting. Based on the ASMUIO, an adaptive backstepping fault-tolerant control (FTC) is further designed to achieve good tracking performance. The design efficacy is illustrated through comparative simulations of the proposed method against representative methods in the literature.
Fault estimation, fault-tolerant control, linear matrix inequality, perturbation.
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