Control and Stability Characteristics of Gamera II: a Human Powered Helicopter

In the pursuit of the AHS Sikorsky Prize, a team of students from the University of Maryland have built and flown the human powered helicopter Gamera IIXR. Having achieved flights of over 60 seconds and approaching 3 m in altitude, the team has been focusing on stability and control. Three primary stability issues have been identified: translational drift, coupled yaw-flap oscillations, and long period forward pitch behavior. Methods for alleviating these issues include: (1) an active control system that varies rotor RPM, and (2) a teetering rotor hub in conjunction with pitch-flap (ƍ3) coupling. Both of these techniques have been successfully implemented on the latest vehicle, Gamera IID.