A root locus approach to loop transfer recovery based controller design

A novel approach to loop transfer recovery design is presented, that is applicable in the scope of TFL/LTR (Target Feedback Loop / Loop Transfer Recovery) controller design, whose best known variant is LQG/LTR (Linear Quadratic Gaussian / Loop Transfer Recovery) design. The proposed method requires solely the adjustment of two scalar parameters, which must satisfy an inequality that depends on the plant model, the desired quality of loop recovery, and desired controller pole locations - chosen from the root locus. For illustrative purposes a (numerical) SISO design example is presented, although the method applies to MIMO systems as well.