Development of a Hybrid Micro Air Vehicle Capable of Controlled Transition

Abstract

Micro air vehicles often have limited versatility with restrictions on endurance, agility, hover capability, and payload. A hybrid vehicle is proposed that addresses these constraints using a tailsitter design and novel dual tilting rotors. Transition between hover and forward flight is achieved by rotating the body with control authority provided by only the tilting rotors in a minimally actuated design. The addition of tilting rotors allows for improved actuation capacity and control throughout transition. A cascaded control methodology is presented that accounts for large body rotations using the resolved tilt-twist method. Nonlinear backstepping converts the control forces and moments to actuator inputs while considering the unique vehicle dynamics. A prototype vehicle is constructed with the control strategy running in an embedded flight controller and transition is demonstrated experimentally. The vehicle is able to maintain control authority throughout transition while also achieving increased efficiency in forward flight.