Design and Analysis of Several State-Feedback Fault-Tolerant Control Strategies for Semi-Active Suspensions

Abstract

Abstract The design of State-Feedback Fault Tolerant control for Semi-Active Suspension Systems is considered in this work, that exploits diverse simple-to-implement approaches. The suspension damper is assumed to undergo multiplicative (time-varying) faults, that can be estimated by (four) modular fault estimation observers. With these fault estimations, active fault tolerant control (FTC) schemes can be synthesized, based on the reconfiguration of nominal State-Feedback policies. Seven approaches are discussed: i) Direct fault compensation; ii) Pole placement compensation; iii) Fault-dependent pole placement; iv) Linear-fault-dependent Linear Quadratic Regulator (LQR) design; v) Polynomially-fault-dependent LQR parameters; vi) LQR with Fault-dependent controlled outputs; vii) Heuristic (vehicle-oriented) fault-dependent LQR synthesis. The performances of these methods are analysed and compared through realistic and high-fidelity simulations. Results show the overall good operation of the latter approaches to compensate fault events and maintain performances.