Integrated Trailing-Edge Flaps and Servotabs for Helicopter Primary Control

The comprehensive analysis University of Maryland Advanced Rotor Code (UMARC) was used to quantify the capabilities of trailing-edge flaps (TEFs) for helicopter vibration reduction and performance improvement. The rotor performance in hover was improved with a combination of torsionally softer blades and positive TEF deflections. Suitable combinations of lower harmonic TEF inputs were shown capable of reducing the rotor power requirement by about 4-5% at an advance ratio of μ = 0.4. The TEF was shown to be capable of suppressing vibratory loads at a range of forward speeds, using half peak-to-peak deflections of about 5 • -10 • . Softening the blades in torsion resulted in larger flap actuation requirements for vibration reduction. A combination of 1, 2, 3, 4, and 5/rev TEF inputs resulted in a power reduction of 1.5%, while also reducing certain vibratory loads by more than 50% in high-speed forward flight. Nomenclature C cblade section chord force (positive towards leading edge) coefficient C m blade section pitching moment coefficient C n blade section normal force coefficientrev hub longitudinal shear, lb F y N b /rev hub lateral shear, lb F z N b /rev hub vertical shear, lb f x blade root lateral shear, lb f y blade root longitudinal shear, lb f z blade root vertical shear, lb GJ blade torsional rigidity, lb ft 2 HPP half peak-to-peak J 1 , J 2 vibration objective functions L/D lift-to-drag ratio M blade section Mach number M x N b /rev hub roll moment, lb-ft M y N b /rev hub pitch moment,

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“…15). The blades are modeled as second-order, nonlinear, Euler-Bernoulli beams capable of undergoing coupled flap, lag, torsion, and axial motion.…”

Section: Analytical Modelmentioning

confidence: 93%

Trailing-Edge Flaps for Rotor Performance Enhancement and Vibration Reduction

Ravichandran¹,

Chopra²,

Wake³

et al. 2013

J Am Helicopter Soc

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“…And from 2005 to 2006, Bao and Allen in Maryland conducted experiments of the ECR system [6]. Then Falls and Chopra made some optimizations of the trailing-edge flap in 2007 [7] . In China, the research began in 2002, Lu yang and Gao zheng have done theoretic and experimental research on the ECR system [8][9] .…”

Section: Introductionmentioning

confidence: 99%

Improved Algorithm Simulation of Adaptive Blade Pitch Control for Electrically Controlled Rotor

Dong

2012

2012 Second International Conference on Intelligent System Design and Engineering Application

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Based on the former adaptive blade pitch control method of the Electrically Controlled Rotor in time domain, two improved control algorithms are proposed. One method is through adding a weight-constrained function for active control filter, which can prevent the divergent of control system caused by interference signal of error channel. The other method is through adding a desired signal of scaling factor to replace the identification process of the forward path. The algorithm can enhance the real time characteristics and the response characteristics of control system. In addition, the comparison between two improved methods and the former method is conducted, and the simulation analysis is made based on the matlab/simulink. The simulation results show that the two proposed methods have better system robustness, and the control characteristics are obviously superior to the former system.

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“…And from 2005 to 2006, Bao and Allen in Maryland conducted experiments of the ECR system [6]. Then Falls and Chopra made some optimizations of the trailing-edge flap in 2007 [7]. In China, the research began in 2002, Lu yang and Gao zheng have done theoretic and experimental research on the RCE system [8][9].…”

Section: Introductionmentioning

confidence: 99%

Simulation of Adaptive Blade Pitch Control for Elctrically Controlled Rotor

Liang

Yang

2010

2010 International Conference on Intelligent System Design and Engineering Application

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Electrically Controlled Rotor (ECR) is a new concept rotor system which was brought forward at the beginning of the 21st century. A control strategy of the ECR system is given out in this paper. An adaptive blade pitch control strategy of the ECR system is proposed, which is based on the adaptive filter with least mean aquare (LMS) algorithm. A secondary path on-line identification method with random signal is added into the control system. To eliminate the bad effect of the random signal, a secondary path filter is used. The effectiveness of the control strategy is verified through SIMULINK simulation. The results show that the control strategy can adapt the changes automatically in different filght conditions of the helicopter, and the actual blade pitch value will reach the required pitch value in less than 2 seconds.

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Integrated Trailing-Edge Flaps and Servotabs for Helicopter Primary Control

Cited by 14 publications

References 10 publications

Trailing-Edge Flaps for Rotor Performance Enhancement and Vibration Reduction

Trailing-Edge Flaps for Rotor Performance Enhancement and Vibration Reduction

Improved Algorithm Simulation of Adaptive Blade Pitch Control for Electrically Controlled Rotor

Simulation of Adaptive Blade Pitch Control for Elctrically Controlled Rotor

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