Improved LTI TDS Model Identification using a Saturation Relay: An Application Example

摘要

The paper attacks the relay-feedback based identification of Linear Time-Invariant Time Delay Systems (LTI TDS) as a part of the autotuning process. Instead of the sole use of the conventional on/off relay, its combination with a saturation relay is presented, which brings more accurate model parameters estimation. In the case of more then two unknown model parameters, it is necessary to apply some technique for frequency response multiple-points identification; here, the Autotune Variation Plus (ATV+) procedure introducing an additional artificial delay is utilized. Limit cycles data are then evaluated via an uncommon time-domain approach supported by numerical solutions via several iterative algorithms. The methodology is, eventually, verified on the parameters' estimation of a laboratory circuit heating LTI TDS model, both, by simulations and real measurements.