Аннотация:
The goal of the work is to create a new method for automatic re-tuning of PI controllers. It is
achieved by solving the following problems. The first problem is to develop a method to identify a
FOPDT estimation model by analyzing the dynamics of a control loop with a PI controller. The
second problem is to demonstrate that the use of the estimated model allows to obtain better processes
in control systems with PI controllers by comparing the resulting FOPDT model with a number of
reduced models. The third problem is to develop a five-stage algorithm for automatic re-tuning of PI
controllers. The fourth problem is to verify the software implementation of the developed algorithm.
The most significant result was that the basis for estimating the FOPDT model in a loop with a
Ziegler-Nichols tuned PI controller was the estimation the ratio of the delay to the time constant of the
FOPDT model based on an assessment of the process overshoot. When the real control plant dynamics
did not match with the dynamics of the FOPDT model this way was found effective for finding the
optimal tuning of the PI controller. The significance of the results obtained was a structural robustness
in case of estimated FOPDT model usage. The effectiveness of the procedure has been demonstrated
on both linear and nonlinear models. The developed procedure is proposed to be used to automate the
procedure of re-tuning SISO control systems when the control loop performance degradation has been
detected.
