Helicopter vibration reduction using robust control [Elektronische Ressource] / vorglegt von Thomas Mannchen

Description

Helicopter Vibration Reduction Using Robust ControlVon der Fakultät Luft- und Raumfahrttechnik der Universität Stuttgartzur Erlangung der Würde eines Doktor-Ingenieurs (Dr.-Ing.)genehmigte AbhandlungVo rg e l eg t vo nThomas Mannchenaus MünchenHauptberichter: Prof. Klaus H. Well, Ph.D.Mitberichter: Prof. Ian Postlethwaite, Ph.D.Tag der mündlichen Prüfung: 10.01.2003Institut für Flugmechanik und FlugregelungUniversität Stuttgart2003IIIAcknowledgementsI would like to take this opportunity to express my gratitude to the many people who haveprovided help and encouragement over the time leading up to and during the developmentof this work. In particular, I would like to thank my supervisor, Professor Klaus Well, for his advice andencouragement. I am grateful as well to Professor Ian Postlethwaite, who has shown anongoing interest in this work and provided valuable comments.Support for this research provided by Eurocopter Deutschland is gratefully acknowledged. Iam particularly indebted to Henning Strehlow and Oliver Dieterich.My contemporaries in the Institute of Flight Mechanics and Control have made my experi-ence at the University of Stuttgart very memorable.On a personal note, I would like to thank my family for their encouragement and support.Finally, my heartfelt thanks to Sandra for her love and understanding.Stuttgart, January 2003Thomas MannchenIVVContentsNotation...........................................................................

Informations

• Publié par: universitat_stuttgart
• Publié le: 01 janvier 2005
• Nombre de lectures: 51
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Helicopter VUsing Robiust Contrbration Reduction ol

Von der Fakultät Luft- und Raumfahrttechnik der Universität Stuttgart
zur Erlangung der Würde eines Doktor-Ingenieurs (Dr.-Ing.)
genehmigte Abhandlung

r:eberichtHauptMitberichter:

Vorgelegt von

hen ManncThomas

aus München

Prof. Klaus H. Well, Ph.D.
Prof. Ian Postlethwaite, Ph.D.

Tag der mündlichen Prüfung:10.01.2003

Institut für Flugmechanik und Flugregelung
Universität Stuttgart
2003

Acknowledgements

III

I would like to take this opportunity to express my gratitude to the many people who have
provided help and encouragement over the time leading up to and during the development
of this work.
In particular, I would like to thank my supervisor, Professor Klaus Well, for his advice and
encouragement. I am grateful as well to Professor Ian Postlethwaite, who has shown an
ongoing interest in this work and provided valuable comments.
Support for this research provided by Eurocopter Deutschland is gratefully acknowledged. I
am particularly indebted to Henning Strehlow and Oliver Dieterich.
My contemporaries in the Institute of Flight Mechanics and Control have made my experi-
ence at the University of Stuttgart very memorable.
On a personal note, I would like to thank my family for their encouragement and support.
Finally, my heartfelt thanks to Sandra for her love and understanding.

ry 2003art, JanuagStutt

henThomas Mannc

IV

entsCont

V

Notation.........................................................................................................................VIII

Abstract...........................................................................................................................XII

Kurzfassung..................................................................................................................XIII

1apterhC1........................................................................................................................Introduction1..........................................................................................................Helicopter1.11.2Rotor Induced Vibration....................................................................................2
1.3Individual Blade Control...................................................................................5
1.4Benefits of Individual Blade Control................................................................6
1.5State-of-the-Art.................................................................................................7
1.6Motivation.........................................................................................................7
1.7Research Objective............................................................................................9
1.8Overview of Content.........................................................................................9

2apterhCModel Description and Analysis.....................................................................................10
10..................................................................................Analytical Rotor Model2.12.1.1Flap and Lag Dynamics......................................................................11
2.1.2Aerodynamics.....................................................................................14
2.1.3Loads, Vibrations, and Hub Filtering..................................................15
2.1.4Multiblade Coordinate Transformation...............................................17
2.1.5Trimming.............................................................................................18
2.1.6Linearization.......................................................................................19
2.2Camrad II Rotor Model...................................................................................21
2.2.1Frequency Domain Analysis...............................................................22
2.2.2Time Domain Analysis........................................................................25
2.2.3Actuator Dynamics..............................................................................27
2.3Fuselage Model...............................................................................................28
2.3.1Implementation...................................................................................28
2.3.2Structural Damping.............................................................................29
2.3.3Coupling and Mode Shapes................................................................30
2.3.4Pole Locations of the Coupled System...............................................30

VI

2.3.5Number of Fuselage Modes Required.................................................33
2.4Pe2.4.1riodicityMultiharmonic.................................... Responses......................................................................................................................................3838
2.4.2Transmissibility of Single Harmonic Blade Inputs.............................39
2.4.3Hub Filtering.......................................................................................39
2.4.4Periodicity of the Total System in MBC.............................................41
2.4.5Measuring Periodicity in State-Space Realizations............................42

3apterhCControl Law for the N-Blade Rotor...............................................................................45
3.1N-Blade Rotor Effects.....................................................................................45
3.2Optimal Output Feedback Control Law Design.............................................46
3.3Vibration Reduction Results...........................................................................47
3.4Singular Value Analysis of the Plant..............................................................49
4apterhCModel Reduction..............................................................................................................50
4.1Reduction of Linear Time-Constant Systems.................................................50
4.2Extension to Linear Time-Periodic Systems...................................................52
5apterhCController Design.............................................................................................................56
5.1Control Objectives..........................................................................................56
5.2Choice of Control Design Method..................................................................57
5.3H Control Design.........................................................................................57
5.3.1The HNorm.....................................................................................57
5.3.2Linear Fractional Transformation.......................................................57
5.3.3Frequency Domain Design Specifications..........................................58
5.3.4General Control Problem Formulation................................................60
5.4Controller Design Setup..................................................................................61
5.4.1Modelling the Output Disturbance......................................................61
5.4.2Selection of Outputs to be Controlled.................................................63
5.4.3Weighting of Individual Modes...........................................................64
5.4.4Uncertainty Modelling........................................................................66
5.4.5Low Frequency Control Authority......................................................66
5.4.6Weighting the Plant Output.................................................................67
5.4.7Summary of Weighting Functions.......................................................67
5.5Periodic Controller..........................................................................................68
5.5.1Observer-Based Realization................................................................68
5.5.2Design at Equally Spaced Points Around the Azimuth......................68
5.6Systematic Adjustment of Weighting Functions.............................................70
5.6.1Performance Index..............................................................................70
5.6.2Optimization........................................................................................71
5.6.3Limitations..........................................................................................73

IVI

6apterhCResults & Analysis...........................................................................................................75
6.1Constant Controller.........................................................................................75
6.1.1Frequency Domain Analysis...............................................................75
6.1.2Time Domain Analysis........................................................................76
6.2Periodic Controller..........................................................................................77
6.2.16.2.2VTialimeda-Ptieron of the Giodic Closead-Loop Siin-Scheduling Approacmulationsh.................................................................................8177
6.2.3Disturbance Rejection.........................................................................83
6.3Fuselage Vibration Controller...................