Dl. Chu et al., REGULARIZATION OF SINGULAR SYSTEMS BY DERIVATIVE AND PROPORTIONAL OUTPUT-FEEDBACK, SIAM journal on matrix analysis and applications, 19(1), 1998, pp. 21-38
The problem of the regularization of singular systems by derivative an
d proportional output feedback is studied. Necessary and sufficient co
nditions are given to guarantee the existence of a derivative and prop
ortional output feedback such that the closed-loop system is regular a
nd of index at most 1. It is also shown that the closed-loop system be
comes strongly controllable and observable by using this feedback.