Comparing approaches to constrained design of integrating controllers

The paper discusses challenges related to design and education of the simplest integrating controllers for systems with the dominant first order plants and possible long dead time that obviously represent the most frequently treated control task. Based on experience achieved in research and education of the course “Constrained PID Control” Huba and Simunek (2007), three different approaches comprising the traditional PI control, the IMC approach and the newly developed disturbance observer (DO) based PI control are compared from different points of view. By designing and experimentally evaluating controllers for simple plants, students are encouraged to experience pros and cons of particular approaches. In this way, the modular design of constrained DO based PI control with different filtering properties based on deeper analysis of the core structure of the P controller with different types of nonmodelled dynamics approximations is shown as the most flexible and simultaneously sufficiently open and general alternative for stable, integral and unstable systems with possible long delays.