Reduced-order controller synthesis with regional pole constraint

A reduced order output feedback controller is designed for a linear time invariant system, which guarantees that the closed loop poles are placed within some pre-specified stability region in the complex plane. A convex approximation of the non-convex constraints is used to pose a sequence of semi-definite programs, which provide the lowest order proper controller satisfying the approximate constraints. The proposed method is demonstrated on two practical controller design applications.