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_∞ loop shaping controller on the Carnegie Mellon University (CMU) Yamaha R-50 robotic helicopter. This gain-scheduled H_∞ 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.