PD/PID controller tuning based on model approximations: Model reduction of some unstable and higher order nonlinear models

Abstract

A model reduction technique based on optimization theory is presented, where a possible higher order system/model is approximated with an unstable DIPTD model by using only step response data. The DIPTD model is used to tune PD/PID controllers for the underlying possible higher order system. Numerous examples are used to illustrate the theory, i.e. both linear and nonlinear models. The Pareto Optimal controller is used as a reference controller.

Keywords

• PD and PID controllers
• tuning
• double integrating system
• time delay
• maximum time delay error
• relative time delay margin
• robustness
• performance
• Pareto Optimal