Design of switched unknown input fault estimator with a combination of H∞ performance and adaptive law for faulty Lipschitz switched systems

The article aims to introduce a fault estimator drawing on an unknown input structure that can track actuator faults by combining H∞ performance and a novel adaptive law while reducing the effects of unknown inputs and mitigating disturbances on estimation errors. In the design process of the proposed estimator, the multiple Lyapunov stability conditions are modified. Then, with the help of adaptive dynamics, the design problem is written as a collection of linear matrix inequalities. Additionally, by combining the modified Lyapunov stability condition with the structure of a persistent dwell time, limitations on the switching rule are extracted to ensure the H∞ performance with a non-weighted concept. Therefore, the designed estimator is resistant to different switching rules and reduces the influence of disturbances on estimation error dynamics with specific physical meaning. Finally, the proposed scheme is simulated on two commonly used industrial systems, and its performance is evaluated against various faults. Simulation outcomes demonstrate the accuracy and convergence speed of the recommended strategy.