An ℒ₁ adaptive pitch controller for miniature air vehicles

One of the challenges in designing low level control loops for Micro Air Vehicles (MAVs) is that the manufacturing process for airframes is not consistent enough to ensure uniform aerodynamic properties. Therefore, there is a significant need for robust adaptive control techniques that are computationally simple. Conventional Model Reference Adaptive Controllers (MRAC) have proved to be very useful in a number of flight tests over the past years. However, a major drawback of this control architecture is that during the transient the control signal or the system output can exhibit large oscillations. This requires intensive Monte-Carlo testing for all possible variations in all possible scenarios before each flight test. This paper presents preliminary results for a novel adaptive control technique that is both computationally simple, and has uniform bounded transient response. The effectiveness of the proposed control scheme is demonstrated through simulation results produced by a medium-fidelity hardware-in-the-loop simulator as well as flight test results on a five foot wingspan unmanned air vehicle.