/spl Hscr//sub /spl infin// design of switching surfaces for sliding modes control with non-matching disturbances

A guaranteed cost /spl Hscr//sub /spl infin//-norm design is presented for sliding surfaces in variable structure controllers. This procedure is suitable for approximate rejection of non-matching disturbances. Both unstructured signal disturbances and structured convex-bounded model uncertainties are considered. A state-space convex optimization approach, via LMIs, is employed in the surface design.