I. Introduction
A PROBLEM of major importance in control applications is the synthesis of linear feedback control systems via pole assignment. As known, when all of the state variables of a time-invariant system are completely controllable and measurable, the closed-loop poles of the system can be placed at any desired locations on the complex plane with state feedback through appropriate gains [15]. Since the performance of a feedback control system is mainly determined by its closed-loop poles, pole assignment has been a very effective approach to designing feedback control systems for decades, especially for multivariate systems.