Helicopter slung load control using lagged cable angle feedback

Jayanth Krishnamurthi, Joseph Francis Horn

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A control design method to address stability and handling qualities issues associated with helicopter slung load operations in hover and low speed is presented. A low-order model is developed using first principle physics, with application of basic control techniques. Subsequently, a nonlinear slung load model is developed and integrated with the GENHEL-PSU simulation of the UH-60. Linear model frequency responses are verified against Aeroflightdynamics Directorate (AFDD) OVERCAST models and flight data, showing good correlation in the relevant frequency ranges. A control architecture based on dynamic inversion is developed, combining fuselage and load state feedback. Slung load states are added in feedback linearization, and lagged cable angle feedback is introduced. The controller is shown to reduce load oscillations with trade-offs in pilot response. A controller that uses only lagged cable angle feedback (and no cable state feedback) is also investigated and found to provide good load stabilization without the use of noisy cable angle and rate sensor signals. Sensitivity to parameter variations and optimization methodologies are considered in aiding the design process. Nonlinear batch and real-time simulations are conducted to evaluate performance of the controller.

Original languageEnglish (US)
Article number022011
JournalJournal of the American Helicopter Society
Volume60
Issue number2
DOIs
StatePublished - Apr 1 2015

Fingerprint

Slings
Helicopters
Cables
Feedback
State feedback
Controllers
Feedback linearization
Fuselages
Frequency response
Physics
Stabilization
Sensors

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Aerospace Engineering
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

@article{0e58f67567c24730991993bef1626847,
title = "Helicopter slung load control using lagged cable angle feedback",
abstract = "A control design method to address stability and handling qualities issues associated with helicopter slung load operations in hover and low speed is presented. A low-order model is developed using first principle physics, with application of basic control techniques. Subsequently, a nonlinear slung load model is developed and integrated with the GENHEL-PSU simulation of the UH-60. Linear model frequency responses are verified against Aeroflightdynamics Directorate (AFDD) OVERCAST models and flight data, showing good correlation in the relevant frequency ranges. A control architecture based on dynamic inversion is developed, combining fuselage and load state feedback. Slung load states are added in feedback linearization, and lagged cable angle feedback is introduced. The controller is shown to reduce load oscillations with trade-offs in pilot response. A controller that uses only lagged cable angle feedback (and no cable state feedback) is also investigated and found to provide good load stabilization without the use of noisy cable angle and rate sensor signals. Sensitivity to parameter variations and optimization methodologies are considered in aiding the design process. Nonlinear batch and real-time simulations are conducted to evaluate performance of the controller.",
author = "Jayanth Krishnamurthi and Horn, {Joseph Francis}",
year = "2015",
month = "4",
day = "1",
doi = "10.4050/JAHS.60.022011",
language = "English (US)",
volume = "60",
journal = "Journal of the American Helicopter Society",
issn = "0002-8711",
publisher = "American Helicopter Society",
number = "2",

}

Helicopter slung load control using lagged cable angle feedback. / Krishnamurthi, Jayanth; Horn, Joseph Francis.

In: Journal of the American Helicopter Society, Vol. 60, No. 2, 022011, 01.04.2015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Helicopter slung load control using lagged cable angle feedback

AU - Krishnamurthi, Jayanth

AU - Horn, Joseph Francis

PY - 2015/4/1

Y1 - 2015/4/1

N2 - A control design method to address stability and handling qualities issues associated with helicopter slung load operations in hover and low speed is presented. A low-order model is developed using first principle physics, with application of basic control techniques. Subsequently, a nonlinear slung load model is developed and integrated with the GENHEL-PSU simulation of the UH-60. Linear model frequency responses are verified against Aeroflightdynamics Directorate (AFDD) OVERCAST models and flight data, showing good correlation in the relevant frequency ranges. A control architecture based on dynamic inversion is developed, combining fuselage and load state feedback. Slung load states are added in feedback linearization, and lagged cable angle feedback is introduced. The controller is shown to reduce load oscillations with trade-offs in pilot response. A controller that uses only lagged cable angle feedback (and no cable state feedback) is also investigated and found to provide good load stabilization without the use of noisy cable angle and rate sensor signals. Sensitivity to parameter variations and optimization methodologies are considered in aiding the design process. Nonlinear batch and real-time simulations are conducted to evaluate performance of the controller.

AB - A control design method to address stability and handling qualities issues associated with helicopter slung load operations in hover and low speed is presented. A low-order model is developed using first principle physics, with application of basic control techniques. Subsequently, a nonlinear slung load model is developed and integrated with the GENHEL-PSU simulation of the UH-60. Linear model frequency responses are verified against Aeroflightdynamics Directorate (AFDD) OVERCAST models and flight data, showing good correlation in the relevant frequency ranges. A control architecture based on dynamic inversion is developed, combining fuselage and load state feedback. Slung load states are added in feedback linearization, and lagged cable angle feedback is introduced. The controller is shown to reduce load oscillations with trade-offs in pilot response. A controller that uses only lagged cable angle feedback (and no cable state feedback) is also investigated and found to provide good load stabilization without the use of noisy cable angle and rate sensor signals. Sensitivity to parameter variations and optimization methodologies are considered in aiding the design process. Nonlinear batch and real-time simulations are conducted to evaluate performance of the controller.

UR - http://www.scopus.com/inward/record.url?scp=84927606255&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84927606255&partnerID=8YFLogxK

U2 - 10.4050/JAHS.60.022011

DO - 10.4050/JAHS.60.022011

M3 - Article

VL - 60

JO - Journal of the American Helicopter Society

JF - Journal of the American Helicopter Society

SN - 0002-8711

IS - 2

M1 - 022011

ER -