Flight Testing and Model Based Control of a Shrouded Rotor Micro Air Vehicle in Hover with Edgewise Gusts

摘要

This paper focuses on the feedback control system development and flight testing of a shrouded rotor MAV with anti-torque vanes (TiShrov) in hover with the presence of edgewise gusts. The vehicle was designed modularly to enable studies on the the differences in flight stability between a shrouded and an unshrouded rotor incorporating either a teetering or a hingeless hub. Effects of asymmetric tip clearance and variations in rotor tip path plane relative to shroud axis on flight stability were studied. A closed loop PID controller was developed and flight tested to mitigate unstable oscillations in flight. System identification studies of the attitude dynamics were conducted and a model based LQR controller was developed. Disturbance rejection capabilities of the controller were tested with the vehicle in edgewise flow. To safeguard the model, the vehicle was constrained in translation on a spherical gimbal setup. Two sources of gust were used: table fan and wind tunnel flow. The controller was successfully able to reject the low intensity gust disturbances from both sources. The shrouded vehicle was found to tolerate up to 2m/s of edgewise gusts whereas the unshrouded rotor configuration could tolerate up to 4.8 m/s of gust. These studies demonstrated that shrouded rotor MAVs are better suited for indoor applications in hover to low speed forward flight with a low level of gusts.