Load alleviation control using dynamic inversion with direct load feedback

Mariano Scaramal, Joseph F. Horn, Umberto Saetti

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper addresses the use of dynamic inversion with direct load feedback to provide combined load alleviation and flight control of rotorocraft. The method is applied to a compound utility rotorcraft with similar airframe properties as a UH-60A along with a lifting wing. The controller makes use of flaperons and horizontal stabilizer in addition to the conventional main rotor / tail rotor blade pitch controls to track pilot commands while also minimizing pitch link loads. The nonlinear simulation is developed in FLIGHTLAB® with structural models of the rotor blades and control system. This model must be linearized to a linear time-invariant (LTI) system to support linear Dynamic Inversion control design. The vehicle dynamics and critical fatigue load are modeled with a linear time-periodic (LTP) model which is converted via harmonic decomposition into a high-order LTI model. This model is then reduced to design controllers across a range of airspeeds. The controllers are tested both in linear model simulations and using the full nonlinear FLIGHTLAB® model. The results show that the load alleviating controller achieves significant reduction in the pitch link peak-to-peak loads with minimal change in response characteristics, indicating that load alleviation can be achieved with no degradation in handling qualities.

Original languageEnglish (US)
Title of host publication77th Annual Vertical Flight Society Forum and Technology Display, FORUM 2021
Subtitle of host publicationThe Future of Vertical Flight
PublisherVertical Flight Society
ISBN (Electronic)9781713830016
StatePublished - 2021
Event77th Annual Vertical Flight Society Forum and Technology Display: The Future of Vertical Flight, FORUM 2021 - Virtual, Online
Duration: May 10 2021May 14 2021

Publication series

Name77th Annual Vertical Flight Society Forum and Technology Display, FORUM 2021: The Future of Vertical Flight

Conference

Conference77th Annual Vertical Flight Society Forum and Technology Display: The Future of Vertical Flight, FORUM 2021
CityVirtual, Online
Period5/10/215/14/21

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Control and Systems Engineering

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