Chattering-free variable structure control with application to flight vehicles

Variable structure control (VSC) is a popular robust control method widely used to cope with uncertain system dynamics. Unfortunately, current VSC always comes with "chattering". Eliminating or alleviating such chattering has motivates numerous research efforts, but most proposed methods for chattering elimination are achieved at the price of control precision and additional heavy computations. In our recent paper (Y. D. Song, et al., March 2004) a novel approach is proposed to completely remove the chattering yet maintain asymptotical system stability. The design philosophy is to directly design the rate of the control (compensating) signal, so that the control input is readily obtained via integration. It is shown that the method can eliminate chattering without sacrificing control precise while at the same time ensuring a bounded and smooth control action. This paper extends the results in (Y. D. Song, et al., March 2004) to a more general higher order nonlinear system. Application of this method to heading direction tracking control of flight vehicles is simulated presented. The results with comparison to traditional VSC and VSC + smoothening are represented.