Durability of a Hybrid Air-land Vehicle

A small hybrid vehicle has been developed and tested that is capable of flying, crawling, and transitioning between aerial and terrestrial locomotion modes. The Morphing Micro Air-Land Vehicle is a 16 inch wingspan craft proposed for advanced reconnaissance missions. Earlier versions of MMALV included several sources of low durability. Original prototypes relied on standard RC servos (modified for continuous rotation) as terrestrial locomotion drive motors. High impulse loads experienced during landing resulted in failure of these components, often after as few as two or three deployments. Battery containment was also an issue. During abrupt landings, the battery often became a destructive projectile within the fuselage. Another source of low durability was the method by which the motor was mounted to the fuselage. This was primarily an issue during the trimming process, during which crashes were sometimes unavoidable. Multiple improvements over the previous prototype are implemented that allow the vehicle to repeatedly survive the high impulse loading experienced during landing and even crashing. Compliance in each wheel-leg mitigates the peak level of the impulse load, and compliance in the terrestrial drive train limits the torque that is transmitted back to the drive motor. The custom-built drive train housing mates closely and is secured firmly to the fuselage. The housing also secures the battery. A motor nacelle designed into the fuselage allows for firm mounting of the motor, as well as reproducible placement and orientation of the motor. This both improved durability and decreased odds of crashing during trim flights. Improved wing designs were investigated to develop higher lift, thus allowing for lower cruising speed, which would reduce the loads experienced during landing.