Design and flight testing of an H∞ controller for a robotic helicopter

Although robotic helicopters have received increasing interest from university, industry, and military research groups, their flight envelope in autonomous operations remains extremely limited. The absence of high-fidelity simulation models has prevented the use of well-established multivariable control techniques for the design of high-bandwidth control systems. Existing controllers are of low bandwidth and cover only small portions of the vehicle's flight envelope. The results of the synergic use of high-fidelity integrated modeling strategies and robust multivariable control techniques for the rapid and reliable design of a high-bandwidth controller for robotic helicopters are presented. The project implemented and flight tested an H-infinity loop shaping controller on the Carnegie Mellon University (CMU) Yamaha R-50 robotic helicopter. During the flight tests, the CMU R-50 flew moderate-speed coordinated maneuvers with a level of tracking performance that exceeds performance reported in the publicly available literature. The authors believe that the results open the road to the implementation on robotic helicopters of full-flight-envelope control systems for complex autonomous missions.