ICNPAA 2010: Mathematical Problems in
Engineering, Aerospace and Sciences

Flapping wings micro aerial vehicles (MAV) flight stability and control presents some difficult challenges. The low moments of inertia of MAVs make them vulnerable to rapid angular accelerations, a problem further complicated by the fact that aerodynamic damping of angular rates decreases with a reduction in wingspan. Another potential source of instability for MAVs is the relative magnitudes of wind gusts, which are much higher at the MAV scale than for larger aircraft. Other problem occurs with influence of flapping wings on MAV’s body motion. The birds and flying insects, the biological counterpart of mechanical MAVs, can offer some important insights into how one may best be able to overcome these problems. Biological systems, while forceful evidence of the importance of vision in flight, do not, however, in and of themselves warrant a computer-vision based approach to MAV autonomy. Fundamentally, flight stability and control requires measurement of the MAV’s angular orientation. While for larger aircraft this is typically estimated through the integration of the aircraft’s angular rates or accelerations, a vision-based system can directly measure the MAV’s orientation with respect to the ground. The two degrees of freedom critical for stability  the bank angle and the pitch angle  can be derived from a line corresponding to the horizon as seen from a forward facing camera on the aircraft. Therefore, we have developed a vision-based horizon-detection algorithm that lies at the core of our flight stability system.