Helicopter maneuver performance with active load limiting

Abstract

This paper expands on a previously developed real-time load limiting for critical helicopter components that are subjected to significant fatigue loading. The (structural) load limiting scheme, which is posed as an optimal control problem where estimate of control margin associated with the component load limit is used to arrive at load limiting, is developed within a Dynamic Inversion control architecture. The integration of the load limiting via Model Predictive Control (MPC) within the Dynamic Inversion environment is described in detail. The developed controller resulting from this integration is evaluated using nonlinear model simulations for its ability to limit harmonic pitch link loads and its direct effect on maneuver performance for test cases including attitude and rate command maneuvers.