Individual Blade Control for Component Load Alleviation using a Model Predictive Control Formulation

Abstract

This paper considers synthesis of a load alleviation scheme based on active rotor control for helicopter component life extension. The proposed load alleviation scheme is formulated in a model predictive framework. Using a reduced order coupled body/rotor/inflow dynamic model onboard the vehicle, real-time estimates of component loads arising due to vehicle maneuvers are generated. The load estimates in turn are used in an optimal control formulation to obtain the higher harmonic individual blade control (IBC) inputs needed to reduce selected harmonics of component loads. The performance of the proposed component load alleviation using IBC scheme is implemented in a comprehensive nonlinear model of a generic helicopter. Nonlinear model simulations show that significant individual harmonic load reduction can be obtained with very little impact on the maneuver performance and minimal impact on the uncontrolled harmonics of component loads.