Flight Active Disturbance Rejection Control design and performance analysis

Active Disturbance Rejection Control (ADRC) is designed for the flight attitude control. It outperforms PD control in the classical time- and frequency-domain simultaneously. With regard to the structured uncertainties in the aerodynamics, two main uncertain factors, resume moment coefficient and control moment coefficient, are separated from the certain part of the closed-loop system by μ analysis approach. A numerical seeking method for polynomial roots is applied to obtain stability regions in the 2-D plane for the two aerodynamic coefficients, and its physical meaning is more straightforward than that of traditional stability margin. The results demonstrate that ADRC can tolerate larger structured uncertainty stability region than traditional PD control can. Some deficiencies on stability boundary calculation with μ analysis approach are pointed out.