Nyquist Stability Analysis of the Quadruple-Tank Process with Kalman Filter-Based Control

Multivariable processes in control engineering consistently pose significant challenges in designing stable and efficient control systems due to their inherent complexity and variable interactions. Among these processes, the 'Quadruple-Tank Process' holds a special position as a crucial laboratory and research platform. This system not only effectively demonstrates the characteristics of a multivariable process but also exhibits both minimum-phase and non-minimum-phase behaviors, which further complicates its control. The stability and robust performance of this system against external disturbances and model uncertainties are among the key objectives in its controller design. This article provides an in-depth analysis of the stability of the quadruple-tank process under Kalman filter control, focusing on the Nyquist Characteristic Loci for both minimum-phase and non-minimum-phase configurations. The Kalman filter is an optimal recursive algorithm used to estimate the states of a dynamical system from noisy measurements. In control applications, the Kalman filter acts as a state observer, providing accurate estimates of the system's state variables.

کلیدواژه ها:

Kalman filter ، Nyquist ، minimum-phase ، non-minimum-phase