Identification of First Order Plants by Relay Feedback with Non-symmetrical Oscillations
The paper deals with the approximation of the systems with dominant first order dynamics by the Integrator Plus Dead Time (IPDT) model. They are attractive especially in control of unstable plants, where an open-loop identification may not be applied. This paper updates a previously published contribution based on analysis of the non-symmetrical oscillations with possible offset arising typically under relay control that has been improved to prevent computational errors in the case of a negligible disturbances, when the relay on and off times are nearly equal over one control period. The analytical results are followed by the experiments with several laboratory plant models. The obtained model parameters are used to tune disturbance observer based controllers to illustrate the performance of the proposed method in real applications.
KeywordsClosed loop identification Relay control First order model
This work has been partially supported by the grants APVV-0343-12 Computer aided robust nonlinear control design and VEGA 1/0937/14 Advanced methods for nonlinear modeling and control of mechatronic systems.
- 6.Huba, M.: Performance portrait method: a new CAD tool. In: 10th IFAC Symposium on Advances in Control Education (ACE), Sheffield, UK (2013)Google Scholar
- 8.Huba, T., Huba, M., Ťapák, P., Bisták, P.: New thermo-optical plants for laboratory experiments. In: IFAC World Congress, Cape Town, South Africa (2014)Google Scholar
- 9.Liu, T., Gao, F.: Industrial Process Identification and Control Design: Step-test and Relay-experiment-based Methods. Advances in Industrial Control. Springer, London (2011)Google Scholar