Design and flight testing of a gain-scheduled H∞ loop shaping controller for wide-envelope flight of a robotic helicopter

Complex future missions in civilian and military scenarios will require robotic helicopters to have controllers that exploit their full dynamic capabilities. The absence of high-fidelity simulation models has prevented the use of well established multivariable control techniques for the design of high-bandwidth full-flight-envelope control systems. Existing model-based controllers are of low bandwidth and cover only small portions,of the vehicle's flight envelope. In this paper we present the results of the synergistic use of high-fidelity integrated modeling strategies, robust multivariable control techniques, and classical gain scheduling for the rapid and reliable design of a high-bandwidth full-flight-envelope controller for robotic helicopters. We implemented and flight tested a gain-scheduled H-infinity loop shaping controller on the Carnegie Mellon University (CMU) Yamaha R-50 robotic helicopter. This gain-scheduled H-infinity loop shaping controller is the first of its kind to be flight tested on a helicopter (manned or unmanned). During the flight tests, the CMU R-50 flew moderate to high-speed maneuvers. We believe that our modeling/control approach delivers controllers that exploit the full dynamic capability of the airframe and thus are ready to be used by higher level navigation systems for complex autonomous missions.