Robust sampled-data control for vehicle steering systems

In industrial control, computer control is widely used, which makes the closed-loop system be a sampled-data one containing continuous time and discrete time signals. In contrast to the traditional approximation methods, sampled-data synthesis is a direct digital controller design procedure without approximation. Sampled-data control which is capable of stabilizing general nonlinear systems with the intersample behavior taken into account are of great current interest. In the paper robust sampled-data control for a class of nonlinear parametric uncertain systems with constraints on the output imposed by time-domain performances is proposed. Based on the result of robust asymptotic stability of sampled-data systems with constraints on the state, robust sampled-data control for a class of uncertain nonlinear systems with constraints on the output is developed. The problem is formulated for vehicle steering control with constraint on the side slip angle of body. The result is described by some matrix inequalities which could be solved by a proposed iterative algorithm based on the linear matrix inequality technique. Finally, a numerical example is presented to show the result