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Monday, November 23, 2020 | History

3 edition of Tiltrotor vibration reduction through higher harmonic control found in the catalog.

Tiltrotor vibration reduction through higher harmonic control

Tiltrotor vibration reduction through higher harmonic control

  • 213 Want to read
  • 37 Currently reading

Published by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, D.C, Springfield, Va .
Written in English

    Subjects:
  • Rotary wing aircraft.,
  • Helicopters.,
  • Vibration damping.,
  • V-22 aircraft.,
  • Rotor speed.,
  • Aeroelasticity.

  • Edition Notes

    StatementMark W. Nixon, Raymond G. Kvaternik, Settle, T. Ben.
    SeriesNASA-TM -- 112427., NASA technical memorandum -- 112427.
    ContributionsKvaternik, Raymond G., Settle, T. Ben., United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15498467M

    Non-Harmonic Deployment of Trailing-Edge Flaps for Rotor-Performance Enhancement and Vibration Reduction Fifth Decennial AHS Aeromechanics Specialist' Conference Jan Other authorsTitle: Project Engineer at ATA Engineering. Vibration control of the smart structure is realized through four piezoceramic PZT actuators and one PZT sensor bonded to the plate. Active vibration reduction under harmonic excitation. This book is designed to fill the need for a comprehensive resource on noise and vibration control. Several books and journals on noise control, and others on vibration control already exist. most of the simple noise and vibration reduction measures have already been taken and further noise and vibration reduction involves much more.


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Tiltrotor vibration reduction through higher harmonic control Download PDF EPUB FB2

Key words: active control, aeroelasticity, higher harmonic control, HHC, rotorcraft dynamics, tiltrotor, vibration 1. Introduction Rotary-wing aircraft are prone to vibrations due to the intrinsic periodic nature of the airloads acting on the rotor blades.

Tiltrotor aircraft operating in the airplane mode of flight are inherently less. Abstract * The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in the airplane mode of flight, and to evaluate the effectiveness of a Belldeveloped HHC algorithm called MAVSS (Multipoint Adaptive Vibration Suppression System) are presented.

Tiltrotor Vibration Reduction Through Higher Harmonic Control Mark W. Nixon, ARL Vehicle Technology Center; Raymond G. Kvaternik, NASA Langley Research Center; T. Ben Settle, Bell Helicopter Textron, Inc. Ap Your Path: Home > Tiltrotor Vibration Reduction Through Higher Harmonic Control.

A higher harmonic control Tiltrotor vibration reduction through higher harmonic control book investigation was conducted on a full-scale, isolated XV rotor in helicopter mode in the NASA Ames by Foot Wind Tunnel to independently control noise and. Tiltrotor Vibration Reduction Through Higher Harmonic Control.

By T. Ben Settle, Mark W. Nixon and Raymond G. Kvaternik. Abstract. The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in the airplane mode of.

Tiltrotor Vibration Reduction Through Higher Harmonic Control. By Mark Nixon Aerospace, Mark W. Nixon, Raymond G.

Kvaternik and T. Ben Settle. Abstract * The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in. Journal of Guidance, Control, and Dynamics; Journal of Propulsion and Power; Journal of Spacecraft and Rockets; Journal of Thermophysics and Heat Transfer; Browse All Journals; Browse All Virtual Collections; Books.

AIAA Education Series; Library of Flight; Progress in Astronautics and Aeronautics; The Aerospace Press; Browse All Books; Meeting. Tiltrotor Vibration Reduction Through Higher Harmonic Control. * The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control.

Nixon et al., Tiltrotor Vibration Reduction Through Higher Harmonic Control, American Helicopter Society 53rd Annual Forum [CD-ROM], Virginia. Robust harmonic control for helicopter vibration attenuation Force control of semi-active valve lag dampers for vibration reduction in helicopters IET Control Theory &.

Higher Harmonic Control. A dream of helicopter dynamicists is to oscillate the main rotor blades in a manner to reduce the Np loads transmitted into the fuselage.

The idea promises to achieve vibration reduction at the source (i.e., the rotor) and with low weight penalty since no extra actuators need be added to the aircrafts empty weight.

Tiltrotor Vibration Reduction Through Higher Harmonic Control Mark W. Nixon Aerospace Engineer ARL Vehicle Technology Center Hampton, VA Raymond G. Kvaternik Senior Research Engineer NASA Langley Research Center Hampton, VA T. Ben Settle Research Projects Engineer Bell Helicopter Textron, Inc.

Fort Worth, Texas ABSTRACT*. TILTROTOR VIBRATION REDUCTION THROUGH HIGHER HARMONIC CONTROL Mark W. Nixon U.S. Army Vehicle Technology Center NASA Langley Research Center Hampton, Virginia Raymond G.

Kvaternik NASA Langley Research Center Hampton, Virginia T. Ben Settle Bell Helicopter Textron, Inc. Fort Worth, Texas Presented at the American Helicopter Society 53rd Annual.

Higher Harmonic Control. A dream of helicopter dynamicists is to oscillate the main rotor blades in a manner to reduce the Np loads transmitted into the fuselage.

The idea promises to achieve vibration reduction at the source (i.e., the rotor) and with low weight penalty since no extra actuators need be added to the aircrafts empty weight.

Get this from a library. Tiltrotor vibration reduction through higher harmonic control. [Mark W Nixon; Raymond G Kvaternik; T Ben Settle; United States. National Aeronautics and Space Administration.]. Figure 5 is a block diagram of a Higher Harmonic control system for a dual, counter-rotating, coaxial rotor system; and.

Figure 6A is a matrix explanation for the Higher Harmonic control system of a dual, counter-rotating, coaxial rotor system having Forces and moments as represented in Figure 6B. DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT. FIG. 5 is a block diagram of a Higher Harmonic control system for a dual, counter-rotating, coaxial rotor system; and.

FIG. 6A is a matrix explanation for the Higher Harmonic control system of a dual, counter-rotating, coaxial rotor system having Forces and moments as represented in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT.

Forced vibration of damped, single degree of freedom, linear spring mass systems. Finally, we solve the most important vibration problems of all. In engineering practice, we are almost invariably interested in predicting the response of a structure or mechanical system to external forcing.

The vibration reduction of a four-bladed helicopter with dissimilar characteristics is demonstrated using the active twist control method. Numerical results are obtained in forward flight at an advance ratio ofwith a moderate thrust condition of C T /σ = and lock number γ = From both simulation and experiment, the 6th harmonic vibration amplitude was more than degrees within the working speed limits of the engine, while the th and 9th harmonics vibration amplitudes were around degrees within the same speed limits.

Therefore, vibration reduction measures have to be taken for the crankshaft. Tiltrotor Vibration Reduction Through Higher Harmonic Control Regular Price: $ Member price: $ New Comprehensive Time Domain Unsteady Aerodynamics For Flapped Airfoils And Its Application To Rotor Vibration Reduction Using Active Control.

The aim of this paper is the assessment of the capability of controllers based on the combined actuation of flaps and variable-stiffness devices to alleviate helicopter main rotor vibratory hub loads. Trailing-edge flaps are positioned at the rotor blade tip region, whereas variable-stiffness devices are located at the pitch link and at the blade root.

Polychroniadis, M., Achache, M.: Higher harmonic control: flight tests of an experimental system on SA research Gazelle. In: Proceedings of the 42nd Annual Forum of the American Helicopter Society, Washington, D.C., USA, pp. – () Google Scholar.

Benefits to rotor aeromechanics were explored and quantified, including dramatic noise and vibration reduction benefits.

This effort included support from MIT, UCLA, and the University of Maryland. The SMART rotor was tested up to knots with open- and closed-loop excitation to the flaps. Active Control of Structural Response (ACSR) Unlike the HHC and IBC techniques that are intended to reduce the vibration in the rotor system, ACSR approach is designed to attenuate the N/rev vibration in the fuselage, and is one of the most successful helicopter vibration reduction methods at the present time Vibration sensors are placed.

The simultaneous active vibration control of the steady-state housing response at the fourth through seventh mesh harmonics was then tested for a speed range of ?rpm to at 10?rpm increments. Because the sampling rate was set to ?Hz, the highest frequency that can be controlled is limited to below ?Hz.

Naval Postgraduate School Dissertation (Application of Chaos Methods to Helicopter Vibration Reduction Using Higher Harmonic Control) [Martinus M. Sarigul-Klijn, Ramesh Kolar] on *FREE* shipping on qualifying offers. Naval Postgraduate School Dissertation (Application of Chaos Methods to Helicopter Vibration Reduction Using Higher Harmonic Control)Author: Martinus M.

Sarigul-Klijn. Audio Books & Poetry Community Audio Computers, Technology and Science Music, Arts & Culture News & Public Affairs Non-English Audio Spirituality & Religion. Librivox Free Audiobook.

Agar Doa Tidak Tertolak Architecture Insights ADT podcast Autism Spectrum Adult Ed. Performance of minimum energy controllers on tiltrotor aircraft Performance of minimum energy controllers on tiltrotor aircraft Oktay, Tugrul Purpose – The purpose of this article is to evaluate performance of minimum energy controllers thoroughly on a tiltrotor aircraft.

Approach – Minimum energy controllers are designed for tiltrotor aircraft models for helicopter and. An advanced higher harmonic control (HHC) analysis has been developed and applied to investigate its effect on vibration reduction levels, blade and control system fatigue loads, rotor performance, and power requirements of servo-actuators.

The analysis is based on. CONTROL IN ELECTRICAL POWER SYSTEMS”provides suggested harmonic values for power systems: “Computers and allied equipment, such as programmable controllers, frequently require ac sources that have no more than 5% harmonic voltage distortion factor [THD], with the largest single harmonic being no more than 3% of the fundamental voltage.

Overhung rotors are important for use in industrial turbo-machines. The effects of a lateral force can increase as a result of the rotor weight, misalignment, or the operating speed of the suspension system for which the rotor is carrying a transmission connection.

In this paper, the reduction of vibration in supported lateral directions by varying control is discussed in a radial active. 16 hours ago  It can be seen from Figure 9 that the amplitude of the 5th harmonic was always higher than the 3rd one. This indicates the non-imminence of flashover, because the ratio of the 3rd to the 5th harmonic was below one in this case.

However, the 1st, 3rd, and 5th harmonics are higher than the harmonics measured on the non-humidified polluted. The Newmark-β method was adopted to solve the dynamic equation and the simulated vibration responses of drillpipe were calculated.

The results show that the axial models yield harmonic motion. The axial displacement is quite small and the maximum amplitude of the first section is about 6× m.

The transverse displacement is much larger than. The lower rotor control system and the upper rotor control system provide six controls or “knobs” to minimize or theoretically eliminate airframe vibration.

In a dual, counter-rotating, coaxial rotor system, application of a HHC system to the two rotor systems individually but located on the common axis, will yield essentially complete. Pareto points minimizing hub vibration and flap control power are found at flap lengths of 6% and 9% of the rotor length.

This study also explores the variation in rotor hub vibration and flap control power with flying conditions such as the advance ratio and the thrust-to-solidity ratio at the optimum design points.

Nixon M.W. et al, Tiltrotor Vibration Reduction Through Higher Harmonic Control, Journal of the American Helicopter Society, Jul.vol. 43, No. 3, Alexandria, VA, US. The MAVSS control algorithm, is an inherently stable, yet robust time domain control methodology that uses traditional Higher Harmonic Control (HHC) techniques.

In most cases, a mechanically loose connection will yield harmonic levels of vibration (2X, 3X, etc.) and may also yield sub-harmonic levels of vibration (X/2, X/3, etc.).

Vibration caused by mechanically loose connections is often misdiagnosed due to the presence of sub-harmonic vibration levels. PASSIVE VIBRATION REDUCTION ATTENUATOR XMSN FUSEAGE TAIL ROTOR 1,2,3,4. n Blades of Number b t) * * b * sin(n * F F 0 = = O + K Soft Spring K will reduce Oscillatory Force transmitted to Fuselage But will produce excessive static displacement FRAHM ABSORBER t) Fsin(O Y t)/M sin(* -F Y 2 O O = t) Fsin(O M known and fixed is: Assume O.

A generalized predictive control has been developed for the control of the aeroelasticity and structural dynamics of a tiltrotor. Adaptivity is the key feature of the proposed technique. It gives t.

Resilient wheels are extensively used in urban rail transit, especially for tramway systems, owing to its advantages in noise reduction.

A new type of resilient wheel for a metro is designed, and its characteristics of vibration and sound radiation, including the rolling noise of a resilient single wheel coupled with a track, are studied in this paper.Delta robot is typically mounted on a frame and performs high speed pick and place tasks from top to bottom.

Because of its outstanding accelerating capability and higher center of mass, the Delta robot can generate significant frame vibration. Existing trajectory smoothing methods mainly focus on vibration reduction for the robot instead of the frame, and modifying the frame structure.The engines and rotors tilted through 90° and were cross-linked in the event of engine failure.

The rotors were semi-rigid stainless steel with a high twist and no flapping hinges. Control at low speeds was by cyclic and collective blade angle adjustments.

The first hover of the joint Army/NASA XV was performed on 3 May