Switched Integral Suboptimal Second-Order Sliding Mode Control

This paper presents a switched formulation of the suboptimal second-order integral sliding mode control law that has recently appeared in the literature. The integral approach maintains the good properties of the Suboptimal Second Order Sliding Mode (SSOSM) algorithm in terms of chattering alleviation, but, in addition avoids the reaching phase and keeps the controlled system trajectory on the sliding manifold since the initial time instant. Besides these features, the switched formulation adapts the control gains in different regions of the state space, providing the flexibility needed to accommodate different design objectives when moving towards the desired equilibrium. The paper discusses the properties of the proposed algorithm on a realistic example, that is the lateral dynamics control of a ground vehicle in which the yaw-rate tracking is typically made difficult by parametric uncertainties and nonlinear effects arising with large steering angles.