Adaptive Feedfoward Feedback Control Framework

A novel approach is proposed for the suppression of the aircraft's structural vibration to increase the resilience of the flight control law in the presence of the aeroelastic/aeroservoelastic (AE/ASE) interactions. Currently aircrafts with non-adaptive control laws usually include roll-off or notch filters to avoid AE/ASE interactions. However, if changes in the aircraft configuration are significant, the frequencies of the flexible modes of the aircraft may be shifted and the notch filters could become totally ineffective. With the proposed approach, the flexible modes can be consistently estimated in real-time via system identification algorithm. The identified flexible modes information is sought to be injected to the adaptive control algorithm to update a set of pre-chosen basis functions, These are the key elements for the effectiveness of the proposed method. As a result, undesirable effects of elastic modes will be suppressed while the whole system stability being maintained. Two case/analysis scenarios will be considered. First, the feedforward filter topology will be mainly used to reduce any atmospheric induced structural vibration of the aircraft. Second, the adaptive feedback control is triggered to suppress any AE/ASE interactions, and prevent any possible Flutter/Limit Cycle Oscillation (LCO) of the actual flexible aircraft.