Active identification of PI-regulator parameters in the automatic control system for an unstable first-order object

Abstract: The algorithm to identify parameters of the regulator stabilizing the single channel unstable first-order object incoming in the control system is proposed. In order to control an unstable object, the regulator was calculated using the polynomial method. Due to the requirements of astaticism a proportional-integral regulator was chosen. The main point of the method consists in injecting a periodic signal (sinusoids) of a certain frequency and amplitude. To determine the regulator parameters a family of Nyquist hodographs was proposed for a closed system at the regulator parameters values within the specified range. The amplitude and phase of the steady-state value of the output signal are used to construct a special nomogram, which makes possible to determine the regulator parameters.

Keywords: active identification, automatic control system, unstable object, proportional-integral regulator, transient, nyquist pseudohodograph, test sinusoidal signal, special nomogram