Observer-based ℒ _∞ fault-tolerant control for uncertain switched LPV missile autopilot system under input constraint

This paper presents an observer-based switched linear parameter-varying (LPV) fault-tolerant control approach for missile autopilot systems that are vulnerable to actuator failures, input saturation, amplitude-bounded disturbances and model uncertainties. By considering input constraint as modeling parameters, the nonlinear missile dynamics are constructed as a switched LPV system, and each LPV subsystem corresponds to a specific actuator fault case. The general persistent dwell-time (PDT) constraint is adopted to restrict switching behaviors among those LPV subsystems, which covers the commonly employed average dwell time (ADT) or dwell time (DT) as special cases. The stability and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="script">L</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>∞</mml:mi> </mml:mrow> </mml:msub> </mml:math> performance of the established uncertain switched LPV system are guaranteed by designing a piecewise parameter-dependent polytopic controller and a state-observer, which allow for amplitude-bounded disturbances in contrast to the existing studies that focus on energy-bounded disturbance attenuation. The effectiveness and advantage of the proposed switched LPV fault-tolerant control method are illustrated through numerical simulations.