On pole assignment by output feedback

A new result of the problem of pole assignment by output feedback is presented. A simple condition is given under which min (n, m + r − 1) closed-loop poles can be assigned arbitrarily by a gain output feedback, where n, mand r are the dimensions of the state, output and input vectors, respectively. Under the same condition, a new lower bound for the number of poles assignable by a fixed-order dynamic compensator is given which improves considerably on the results of Breach and Pearson (1970) and Ahmari and Vacroux (1973). A design algorithm and illustrative examples are also given.