Controller order reduction techniques for loop shaping procedure

The main objective of loop shaping design methodology is to produce a controller that guarantees robust stability against normalized coprime factor uncertainty. This form of uncertainty was used by Glover and McFarlane [6-8] to obtain an exact solution to the robust stabilization problem. The order of loop shaping controller is typically as high as the model order. Such high order controllers are sometimes difficult to implement due to hardware limitations. In many cases, the higher order controller can be approximated by a reduced order controller with acceptable performance degradation. In this paper, the effectiveness of order reduction techniques is applied on an inverted pendulum.