Determination of Equivalent Dominant Poles and Zeros Using Industrial Specifications

A graphical method and an analytical method are presented to determine the equivalent dominant poles and zeros of a system using assigned industrial specifications. A second-order transfer function with two poles and one finite zero is used to investigate the relationships between industrial specifications and the two poles and one finite zero. Also, it is used to verify the rule of the thumb obtained from Axelby's empirical results. A frequency response data matching method is proposed for fitting a low-order transfer function using the assigned industrial specifications that are obtained from a given high-order transfer function. Thus the equivalent dominant poles and zeros of a high-order system can be determined from the identified low-order model.