Switching Anti-windup Synthesis for Linear Systems Subject to Asymmetric Input Magnitude and Rate Saturation: Application to Aircraft Engines

This article investigates the anti-windup synthesis problem for linear, time-invariant systems subject to asymmetric input magnitude and rate saturation (MRS) under a switching control framework. By developing an MRS model, the original system is augmented as a linear system with magnitude-only saturation. We then partition the input space into several regions based on the signs of the control inputs. The original asymmetric saturation function can be equivalently expressed as a symmetric one in each of these regions, and the saturation levels associated with different regions are different. By utilizing these special properties, we design a separate anti-windup gain for each region of the input space. The switching from one anti-windup gain to another is activated when the input signals leave one region for another. In comparison with the single-gain anti-windup design, this switching anti-windup design can lead to better performance since the switching among multiple anti-windup gains makes full use of the input capacity. Finally, the proposed method is applied to the aircraft engines. Hardware-in-the-loop testing demonstrates its superiority and practicality.