OPTIMAL DESIGN FOR NOTCH FILTER OF AEROSERVOELASTIC SYSTEMS

The interaction between an aeroelastic system and a flight control system (FCS), namely aeroservoelasticity, may result in aircraft instability, and the corresponding frequencies are lower and vary with aircraft weight configurations significantly. The traditional approach, adopting notch filter for suppressing aeroservoelastic interaction, may have adverse effects on the aircraft controllability and stability. A notch filter optimal design methodology, based on a multi-objective genetic algorithm, is developed with the function of minimizing adverse effects on the rigid fight dynamics. The objective is to minimize the elastic modal frequency response peaks of aeroservoelastic systems subjected to the constraints of the frequency response characteristics of rigid aircraft flight dynamics. Firstly, a penalty function is developed to correct individual fitness functions, and then the frequency and damping parameters of notch filters are optimized. The optimized results indicate that the aeroservoelastic dynamic responses are suppressed while rigid aircraft flight dynamics performance degradation is minimized. Thusly, the proposed method can make full use of high-gain control systems to improve flight performance.