Properties of a combined adaptive/second-order sliding mode control algorithm for some classes of uncertain nonlinear systems

In this paper, a combined adaptive/variable structure control approach is p resented that exploits the good properties of the backstepping procedure an d of a second-order sliding-mode control algorithm. This algorithm enables one to attain the conditions S = 0, (S) over dot = 0 (second-order sliding mode) in a finite time, S = 0 being a predefined sliding manifold. The comb ined approach retains the stability and convergence features of the origina l adaptive strategy. In addition, it allows one to deal with systems with u ncertainties of more general types, ensuring robustness, as well as a reduc tion in thf computational load.