Model matching controller design for disturbance rejection

A new model matching controller design technique is presented to facilitate direct specification of the disturbance response of a closed-loop system. The desired disturbance response characteristics are implicated through an appropriately chosen reference model. This approach substantially reduces the trial-and-error iterations necessary to meet the design requirements. A simple reference model specification procedure allows arbitrary choice for the reference Transfer Function poles (to control response time) while guaranteeing the physical realizability of the controller and asymptotic rejection of various types of disturbances such as step, ramp, etc. The Frequency Domain Controller Synthesis Techniques produce low-order, practically implementable controllers. The power of the design approach is demonstrated by several illustrative examples. It is shown that ensuring good disturbance rejection characteristics is sufficient to guarantee satisfactory set-point response, and not vice versa.