μ-Synthesis control with reference model for aeropropulsion system test facility under dynamic coupling and uncertainty

Abstract

Due to the dynamic coupling and multi-source uncertainties, it is difficult to accurately control the pressure and temperature of the Aeropropulsion System Test Facility (ASTF) in the presence of rapid command and large disturbance. This paper presents the design of μ-synthesis control to solve the problem. By incorporating the pressure ratio into the linear equation of the control valve, the modeling error of ASTF in the low frequency range is effectively reduced. Then, an uncertain model is established by considering various factors, including parameter variations, modeling error in the low frequency range, unmodeled dynamics, and changes in the working point. To address the dynamic coupling, a diagonal reference model with desired performance is incorporated into μ-synthesis. Furthermore, all weighting functions are designed according to the performance requirements. Finally, the μ-controller is obtained by using the standard μ-synthesis method. Simulation results indicate that the μ-controller decouples the pressure and temperature dynamics of ASTF. Compared with the multivariable PI controller, integral-μ controller, and double integral-μ controller, the proposed μ-controller can achieve higher transient accuracy and better disturbance rejection. Moreover, the robustness of the μ-controller is demonstrated by Monte Carlo simulations.