Control of nonholonomic systems with uncertainties via second order sliding modes

The problem of controlling a class of nonholonomic systems affected by uncertainties is addressed in this paper. The idea is to apply the so-called second order sliding mode control methodology. The crucial point is the necessity of reformulating the system model so as to make the uncertain terms appear in matched form. To this end, a suitable change of coordinates is performed and a peculiar sliding manifold is designed upon which a second order sliding mode is enforced. Apart from the robustness features, typical of the sliding mode approach, the proposed law has the advantage of being continuous, thus more acceptable in some applications such as those of mechanical nature