APPLICATION OF PID CONTROLLER IN AUTOMATIC EXTREMUM SEEKING SYSTEMS WITH A NON-STATIONARY SECOND-ORDER PLANT
G.A. Frantsuzova
Novosibirsk State Technical University, Novosibirsk, Russia
Keywords: extremum seeking, PID controller, non-stationary plant, synchronous detection, time scale separationof the processes
Abstract
The possibility of using a typical PID controller to organize an automatic extremum seeking in systems with a second-order dynamic plant and a nonlinear quality function that has a minimum or maximum is considered in this paper. To reduce potential control peaks, it is proposed to modify the controller by moving the proportional and derivative components to the feedback channel relative to the dynamic component of the plant. Additionally, a special low-pass filter is added to suppress the influence of measurement noise. Extremum seeking with incomplete information about the quality function is organized by using an estimate of the extremum characteristic gradient in the controller. A synchronous detection method is proposed for obtaining this estimate. The parameters of the PID controller are determined using the large coefficient method and the modal approach with the desired distribution of roots in the system. The controller calculated in this way ensures the achievement of an extremum in statics, as well as robustness in relation to changes in the dynamic part parameters of the plant. The presented results of numerical simulation of the system in MatLab illustrate its main properties.
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