Generalized Characteristic Ratios: Definition, Assignment, and Application

ABSTRACT

This paper introduces the generalized characteristic ratios concept to shape the transient response of minimum-phase linear time-invariant systems. Unlike the previously defined characteristic ratios devoted to all-pole transfer functions, the generalized characteristic ratios are defined for zero-including systems. The proposed definition is based on the separation of amplitude and time specifications. This means that the generalized characteristic ratios are assigned to reach a low overshoot step response while the generalized time constant is chosen to adjust the transient response speed, independently. Attaining a monotonically decreasing frequency response is the basis of the mentioned assignment. The efficiency of the generalized characteristic ratios to design zeros including controllers like PID and lead (lag) controllers is verified through numerical simulations.

KEYWORDS:

• Characteristic ratio assignment
• Generalized characteristic ratios
• Non-overshooting step response
• Transient response control

ACKNOWLEDGEMENTS

The author likes to acknowledge the author of [23] for his interesting work.

Additional information

Notes on contributors

Mohammad Tabatabaei

Mohammad Tabatabaei received the BE degree in electrical engineering from Sharif University of Technology in 1999. He received the MA degree in biomedical engineering from Amirkabir University of Technology in 2002. In December 2011, he received the PhD degree in control engineering from Islamic Azad University, Science and Research Branch. At present, he is an Assistant Professor in the Department of Electrical Engineering, Khomeinishahr Branch, Islamic Azad University, Isfahan, Iran. His current research interests involve adaptive control and fractional-order systems and controllers.