Optimizing CDM controllers under control signal constraints

An optimization method is proposed to obtain a CDM controller that provides a fast transient response while keeping the control signal below a predetermined limit. In order to determine the performance of the proposed method, a brushless DC motor has been controlled with a Coefficient Diagram Method (CDM) based controller and an optimal PI controller as an application. It has been observed that the proposed method gives comparable controllers to those proposed by MATLAB PID optimization tool in a shorter time for velocity control. The performance of the proposed CDM approach is observed to be superior to the optimal PI controller, when the position of the motor is to be controlled.