Evaluation of a Rotorcraft Autorotation Training Display on a Commercial Flight Training Device

Abstract

This paper outlines the application of a real-time trajectory optimization method for guiding a rotorcraft pilot through an autorotation following a total loss of power. Rotorcraft autorotation is a time-critical maneuver that allows very little margin for error in the timing and magnitude of the pilot’s control inputs. Preliminary tests strongly indicate that successful autorotations may be performed from well within the unsafe operating area of the height-velocity profile of a helicopter by employing a fast and robust optimal algorithm that provides guidance on control inputs through an intuitive pilot display. The algorithm generates optimal aircraft trajectories and control commands via the direct-collocation optimization method, solved using a commercially available nonlinear programming problem solver. The commanded control inputs generated by optimal control formulation are collective and aircraft pitch which are easily tracked by a pilot or can be converted to control actuator commands for automated operation during autorotation. The formulation of the optimal control problem was carefully tailored to emulate solutions resembling those of an expert pilot, accounting for the performance limitations of the rotorcraft as well as safety concerns.