| Title |
Stability Analysis on a PI Observer-Based Control System Combined with a Reduced-Order Model-Based Controller |
| Authors |
손영익(Young Ik Son) ; 아마레 네비옐레울 다니엘(Nebiyeleul Daniel Amare) |
| DOI |
https://doi.org/10.5370/KIEE.2021.70.11.1722 |
| Keywords |
Reduced model based control; PI observer; System stability; Root locus; Motor position control |
| Abstract |
System model order reduction is a popular technique employed by control systems engineers due to its ability to reduce model complexity. However, control systems designed based on reduced-order model may cause closed-loop system instability when applied to the full-order model. In addition, conventional control system improvement methods such as increasing the controller gains or using robust control techniques in particular disturbance observers can further deteriorate system performance. In order to shade light on this phenomena, this paper presents an analytical study of the effects of high observer gain on the stability of observer compensated control systems whereby both the controller and the observer are designed using the reduced-order system model. The analysis is performed by carrying out stability analysis of the closed-loop system through root locus method and Routh-Hurwitz stability criterion. The paper also presents a comparative analysis between placing all the closed-loop poles of the controller at a single location or multiple locations using LQR technique for the aforementioned class of controller. The results obtained from the analysis have been validated through a DC motor position control system application. |