Robust Control of Stochastic Systems Against Bounded Disturbances With Application to Flight Control

This paper investigates the problems of state observer design and observer-based integral sliding-mode control (SMC) for a class of Itô stochastic systems subject to simultaneous input and output disturbances. A new type of sliding-mode-based descriptor observer method is developed to approximate the system state and disturbance vectors. An integral-type SMC scheme is proposed based on the state estimation to stabilize the overall system. The main contributions of this approach are as follows: 1) The desired estimations of state and disturbance vectors can be obtained simultaneously, and 2) in the designed sliding-mode observer, the integral term of the Itô stochastic noise is eliminated in the proposed sliding-mode surface by a matrix design; thus, the reachability of the sliding-mode surface is strictly guaranteed. Finally, the proposed approach is applied to the disturbance reconstruction problem of an F-18 aircraft model to illustrate the effectiveness and applicability.