Performance, Flight Testing of a Shrouded Rotor Micro Air Vehicle in Edgewise Gusts

Experimental studieswere conducted to study the response of a shrouded rotormicro air vehicle to edgewise gusts. In edgewise flow, the thrust, drag, and pitching moment produced by three platforms were compared: elliptic inlet, circular inlet shrouded rotor, and an unshrouded rotor. The elliptic inlet shrouded rotor wasmore efficient in hover but had ahigher penalty in drag andpitchingmoment in edgewiseflow.Cyclic pitch variation of a hingeless rotorwas used to counter these adverse pitching moments. The control authority of the shrouded rotors was at least 80–100% higher than the unshrouded rotor, with the elliptic inlet shrouded rotor producing the highest control moments. By optimizing rotor collective settings, it was possible to reduce the deteriorating effect of edgewise flow on control moments. To increase the control authority and gust tolerance of the shrouded rotor, the cyclic pitch travel and blade planform modifications were made. With a careful selection of rotor solidity, planform, operating revolutions per minute, and cyclic pitch travel, it was possible to achieve a gust tolerance of about 3 m=s for the circular inlet shrouded rotor. Free flight tests were then conducted to study the ability of the vehicle to hover in a given position in the presence of gusts generated from pedestal fans with honeycomb flow straighteners. A combination of VICON and an onboard sensor were used for feedback control. The vehicle was satisfactorily able tomaintain hover position in edgewise gusts of up to 3 m=s.