Research on D robust control of a class of uncertain sampled-data system

For a class of linear sampled-data systems with norm-bounded uncertainty, sufficient conditions for the existence of state feedback control laws with the closed-loop poles in a pre-specified disk and optimizational robust H_∞ performance are derived in terms of linear matrix inequalities (LMIs). The problem of designing the controllers with smaller gain parameters is formulated as a convex problem with LMI constrains, which can be solved by the existing LMI software. Then a class of proportional integral state observers with stronger anti-disturbance is proposed when some states of the system are difficult to be observed. An example shows that the proposed methods ensure less change of dynamic and stable steady performance with the disturbance.