Quaternion-Based Hybrid Attitude Control for an Under-Actuated Flapping Wing Aerial Vehicle

The Challenge for the flight control of flapping wing vehicles has been baffling the control scientists and engineers for decades. Based on this observation, we propose a quaternion-based hybrid attitude control strategy to implement stable hovering and forward flight for a flapping wing vehicle. Specifically, two hysteretic functions are adopted to switch between two control strategies, namely regulating to the desired attitude and pulling back to the stable flight region, so as to deal with a specific geometric constraint, and retain good robustness. Meanwhile, considering the inherent underactuation property of the studied vehicle, the reduced quaternion is introduced to construct feedback signals which are convenient and practical to use. These innovations contribute to a reliable control strategy for the flapping wing vehicles, even with underactuation in attitude. The equilibrium set is proved to be globally asymptotically stable with the help of hybrid control theory. Finally, the proposed controller is implemented in our self-made flapping wing vehicle, with the obtained experimental results clearly showing its superior performance.