A guaranteed cost control problem for a class of linear discrete-time switched systems with norm-bounded uncertainties is considered in this article. The purpose is to construct a switching rule and design a state feedback control law, such that, the closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound for all admissible uncertainties under the constructed switching rule. A sufficient condition for the existence of guaranteed cost controllers and switching rules is derived based on the Lyapunov theory together with the linear matrix inequality (LMI) approach. Furthermore, a convex optimization problem with LMI constraints is formulated to select the suboptimal guaranteed cost controller. A numerical example demonstrates the validity of the proposed design approach.
A parametric method for the gain-scheduled controller design of a linear time-varying system is given. According to the proposed scheduling method,the performance between adjacent characteristic points is preserved by the invariant eigenvalues and the gradually varying eigenvectors.A sufficient stability criterion is given by constructing a series of Lyapunov functions based on the selected discrete characteristic points.An important contribution is that it provides a simple and feasible approach for the design of gain-scheduled controllers for linear time-varying systems,which can guarantee both the global stability and the desired closed-loop performance of the resulted system.The method is applied to the design of a BTT missile autopilot and the simulation results show that the method is superior to the traditional one in sense of either global stability or system performance.
