High-gain observer based decentralised output feedback control for interconnected nonlinear systems with unknown hysteresis input

In this paper, an adaptive dynamic surface control is proposed for a class of interconnected nonlinear systems with inputs preceded by unknown saturated PI hysteresis. By using the proposed dynamic surface control scheme, the explosion of complexity problem when the hysteresis is fused with backstepping design can be eliminated which, together with the estimation of vector norm of the unknown parameters, greatly simplifies the control law and reduces the computational burden. Moreover, by introducing an initialisation technique, the tracking performance of each subsystem can be guaranteed, which, for the first time, establishes the relationship between tracking performance and design parameters in the interconnected system.