REGULARIZATION OF DESCRIPTOR SYSTEMS BY OUTPUT-FEEDBACK

Conditions are given under which a descriptor, or generalized state-sp ace system can be regularized by output feedback. It is shown that und er these conditions, proportional and derivative output feedback contr ols can be constructed such that the closed-loop system is regular and has index at most one. This property ensures the solvability of the r esulting system of dynamic-algebraic equations. A reduced form is give n that allows the system properties as well as the feedback to be dete rmined. The construction procedures used to establish the theory are b ased only on orthogonal matrix decompositions and can therefore be imp lemented in a numerically stable way.