This paper presents a technique for control system design that provides robust stability in the presence of bounded modeling errors. The proposed method is a discrete-time version of a well known sliding mode control technique with saturation functions that generates the boundary layer without requiring either matched uncertainties or smooth functions. It is shown that the boundary layer can be made attractive and that the boundary layer thickness is bounded under mild coditions. It is also shown that asymptotic stability can be guaranteed if the available model is assumed to be perfect. An example is used to illustrate the proposed design technique.

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