Quasi-Continuous High-Order Sliding Mode Controller and Observer Design for Vehicle

Abstract

This paper describes the design of nonlinear robust controller and observer for hypersonic vehicle model which is nonlinear, multivariable, unstable, and includes uncertain parameters. Firstly, the multi-input and multi-output (MIMO) quasi-continuous high-order sliding mode controller is proposed to track the responses of the vehicle to a step change in altitude and velocity. Then, in order to reduce the control chattering, the virtual control is introduced into the design of fourth-order velocity and fifth-order altitude quasi-continuous sliding mode controller. The arbitrary order robust sliding mode differentiator is used to calculate the missing differential which is used in the design of the controller. Furthermore, a nonlinear sliding mode observer is developed to estimate the states that are not available for measurement in hypersonic flight conditions. Finally, the simulation results demonstrate the effectiveness and robustness of the proposed controller and observer.