An adaptive flight control system for a morphing flapping wing aircraft

Abstract

Our prior work1, 2 developed a model for a bird-like flapping wing aircraft using Modified strip theory3 for aerodynamics, a flight dynamics model4 and an adaptive flight controller. This model was simulated in MATLAB/Simulink5 using existing data for the Slow Hawk Ornithopter6. One of the control architectures developed was an Optimal Control Modification (OCM) of an Adaptive Neural Network Inverse Controller, and a gain study was carried out to determine optimal gains. This work expands on the previous work by introducing a new basis function7 and performing a Gain Study on this OCM architecture with a PI controller. The proportional Gain (Kp) , Integral Gain (Ki), Learning rate and the damping constant were optimized using the error metric introduced by Stepanyan8. In this error metric study, Kp was varied from 10 to 100 and a value of 40 was selected. Similarly, Ki was varied from 10 to 105 and a value of 30 was selected, and a good learning rate of 20000 was found. Subsequently, a basic concept of a morphing wing was introduced where wing Properties dependent on camber were assumed to vary linearly with a morphing factor Previously developed control architectures were tested for various morphed states of the wing. OCM with new basis function kept states within limits. The adaptation was able to keep the tracking error low for the pitch rate commanded doublet.