RELIABLE NONLINEAR CONTROL-SYSTEM DESIGN USING DUPLICATED CONTROL ELEMENTS

Reliable L-2 gain bounding (i.e., H-infinity ) controllers for nonline ar systems are designed by using redundant control elements. One senso r and one actuator are duplicated, and the resulting closed-loop syste m is reliable with respect to both the single contingency case and the primary contingency case. The design procedures for reliable controll ers are developed by using the Hamilton-Jacobi inequalities from nonli near H-infinity control theory. Linear reliable controller design meth ods are also obtained by restricting the proposed nonlinear methods to the linear case, and the linear methods are found to be less conserva tive than existing methods for linear reliable controller design. Exam ples are given to illustrate the design procedures for both linear and nonlinear reliable controllers and the advantages of the proposed lin ear method over existing ones. (C) 1997 by John Wiley & Sons, Ltd.