PID Controller Design Application Based on a Boiler Process Model Identification

This paper studies the application results of a method for estimating and tuning the parameters of a digital PID controller. The PID coefficients are computed by means of the identification of the parameters of a discrete-time time invariant input-output dynamic linear model of the process under investigation. The proportional, integral and derivative PID controller terms are thus evaluated by solving a set of algebraic equations obtained by imposing a number of constraints regarding the step response dynamic characteristics of the monitored system. The achieved results are shown when the proposed tuning approach is applied to the real data acquired from a low power boiler used to generate hot water for both domestic use and heating. Therefore, the reliability properties of the PID designed according to the suggested technique are verified by considering different working conditions of the boiler plant. Moreover, these extensive experiments are also used for assessing the overall capabilities of the developed PID design scheme, in the presence of both measurement and modelling errors. Comparisons with different controller design methods available in the related literature are finally reported.