Active Control of Gimballed Rotors Using Swashplate Actuation During Shipboard Engagement Operations

Abstract

An analysis has been developed to investigate the feedback control of gimballed rotor systems using swashplate actuation during transient shipboard engagement operations. The equations of motion for a rigid, three-bladed gimballed rotor system were derived using a Newtonian force summation method. Aerodynamic forces were simulated with a blade-element linear attached flow model. The resulting equations of motion were time integrated along a specified rotor-speed profile. A time domain linear-quadratic-regulator optimal control technique was applied to the equations of motion to minimize the transient rotor response. The physical limits of collective and cyclic pitch inputs in both magnitude and rate were enforced. The maximum transient gimbal tilt angle was reduced by as much as 56% with full knowledge of the ship air-wake environment and 42% with only partial knowledge of the ship airwake environment. Increasing the physical limits of collective and cyclic pitch inputs achieved up to a 70% reduction in the maximum transient gimbal tilt angle.