Unified Design of Robust Discrete-Time Control Systems

The problem of robust control of discrete-time uncertain systems is considered in this paper. By formulating different control objectives into an error system, all problems of interest are reduced to a robust stabilization problem of the error system. The approach is based on quadratic stability. A generalized Riccati equation is obtained by quadratic bound method and its properties are investigated. A much less conservative control law is found by recursively solving the generalized Riccati equation with the stability of the closed-loop system checked at each step. The design technique is applied to a.d.c. motor to illustrate the effectiveness and advantages of the method developed.