Sliding regimes in general non-linear systems: a relative degree approach

In this paper we treat the problem of inducing local sliding regimes on non-linear smooth surfaces defined in the state space of general non-linear controlled systems. A suitable notion of relative degree is found to be of crucial importance in establishing the most salient properties of non-linear systems undergoing sliding motion. The relevance of sliding modes in several control problems as complementary ‘outer loop’ feedback is examined