Vysoké Uˇcení Technické V Brnˇe Odhad Letových
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VYSOKÉ UCEN͡ TECHNICKÉ V BRNEˇ BRNO UNIVERSITY OF TECHNOLOGY FAKULTA INFORMACNÍCHˇ TECHNOLOGIÍ ÚSTAV POCÍTAˇ COVɡ GRAFIKY A MULTIMÉDIÍ FACULTY OF INFORMATION TECHNOLOGY DEPARTMENT OF COMPUTER GRAPHICS AND MULTIMEDIA ODHAD LETOVÝCH PARAMETRU˚ MALÉHO LETOUNU LIGHT AIRPLANE FLIGHT PARAMETERS ESTIMATION DISERTACN͡ PRÁCE PHD THESIS AUTOR PRÁCE Ing. PETR DITTRICH AUTHOR VEDOUCÍ PRÁCE Ing. PETER CHUDÝ, Ph.D. MBA SUPERVISOR BRNO 2016 Abstract This thesis is focused on a light airplane flight parameter estimation, specially aimed at the Evektor SportStar RTC. For the purposes of flight parameter estimation the Equation Error Method, Output Error Method and Recursive Least–Squares methods were used. This thesis is focused on the investigation of the characteristics of the flight parameters of longitudinal motion and the verification, that this estimated parameters corresponds to the measured data and thus create a prerecquisite for a sufficiently accurate airplane model. The estimated flight parameters are compared to the a–priori values obtained using the Tornado, AVL and Datcom softwares. The differences between the a–priori values and estimated flight parameters are also compared to the correction factors published for the subsonic flight regime of an F–18 Hornet model. Keywords Airplane, System Identification, Parameter Estimation, Flight Parameters, Flight Enve- lope, Equations of Motion, Linearization, State–Space Model, Longitudinal Motion, Equa- tion Error Method, Output Error Method, Recursive Least–Squares, Sensors, Flight Path Reconstruction, Kalman Filter, Model Validation. Citation Petr Dittrich: Light airplane flight parameters estimation, PhD thesis, Brno, BUT FIT, 2016 Abstrakt Tato práce je zaměřena na odhad letových parametrůmalého letounu, konkrétněletounu Evektor SportStar RTC. Pro odhad letových parametrůjsou použity metody “Equation Error Method”, “Output Error Method” a metody rekurzivních nejmenších čtverců. Práce je zaměřena na zkoumání charakteristik aerodynamických parametrůpodélného pohybu a ověření, zda takto odhadnuté letové parametry odpovídají naměřeným datům a tudíž vytvářejí předpoklad pro realizaci dostatečněpřesného modelu letadla. Odhadnuté letové parametry jsou dále porovnávány s a–priorními hodnotami získanými s využitím programů Tornado, AVL a softwarovéverze sbírky Datcom. Rozdíly mezi a–priorními hodnotami a odhadnutými letovými paramatery jsou porovnány s korekcemi publikovanými pro subson- ické letové podmínky modelu letounu F–18 Hornet. Klíčová slova Letoun, identifikace systému, odhad parametrů, letové parametry, letová obálka, pohy- bové rovnice, linearizace, stavovýmodel, podélnýpohyb, “Equation Error Method”, “Out- put Error Method”, rekurzivní nejmenšíčtverce, senzory, rekonstrukce letové trajektorie, Kálmánův filtr, validace modelu. Citace Petr Dittrich: Odhad letových parametrůmalého letounu, disertační práce, Brno, FIT VUT v Brně, 2016 Light airplane flight parameters estimation Declaration I hereby declare that this thesis is my genuine work, created under the guidance of my supervisor Assistant professor Peter Chudý. All information sources and publications used are properly cited. ....................... Petr Dittrich August 29th,2016 Acknowledgment I would like to thank my supervisor Assistant professor Peter Chudýfor his guidance and valuable comments on my research work. I also would like to thank my family, my friends and my colleagues at Faculty of Information Technology, Brno University of Technology for their support. c Petr Dittrich, 2016. Tato práce vznikla jako školní dílo na Vysokém učení technickém v Brně, Fakultěinfor- mačních technologií. Práce je chráněna autorským zákonem a její užití bez udělení oprávnění autorem je nezákonné, s výjimkou zákonem definovaných případů. Contents 1Introduction 15 1.1 Objectives of the thesis .............................. 16 1.2 Outline of the thesis ............................... 16 2Systemidentification 18 2.1 Model structure identification .......................... 18 2.2 Parameter estimation ............................... 19 3Modeling 20 3.1 Modeling frames ................................. 20 3.1.1 Earth–related reference frames ..................... 21 3.1.2 Aircraft–related reference frames .................... 22 3.2 Kinematic model ................................. 24 3.2.1 Kinematics of translational motion ................... 24 3.2.2 Kinematics of rotational motion ..................... 26 3.3 Dynamic model .................................. 29 3.3.1 Dynamics of translational motion .................... 29 3.3.2 Dynamics of rotational motion ..................... 30 3.4 Aircraft model .................................. 32 3.4.1 Mass and inertia model ......................... 32 3.4.2 Aerodynamic model ........................... 33 3.4.3 Propulsion model ............................. 34 3.5 Nonlinear Equations of Motion ......................... 35 3.5.1 General nonlinear dynamic system ................... 36 3.5.2 Nonlinear kinematic Equations of Motion ............... 36 3.5.3 Nonlinear dynamic Equations of Motion ................ 37 3.5.4 Separation of dynamic Equations of Motion .............. 39 3.6 Linear Equations of Motion ........................... 40 3.6.1 System linearization ........................... 40 3.6.2 Linear Equations of Motion ....................... 42 4 Flight parameter estimation 45 4.1 Control inputs for system identification ..................... 45 4.1.1 Time domain based inputs for identification .............. 45 4.1.2 Frequency domain based inputs for identification ........... 46 4.1.3 Typical maneuvers in longitudinal and lateral/directional motion .. 47 4.2 Data acquisition ................................. 47 4.2.1 Pilot input and control surface deflection sensors ........... 47 4.2.2 Position, orientation and motion sensors ................ 49 1 4.2.3 Airdata sensors .............................. 50 4.2.4 Engine data sensors ........................... 51 4.3 Flight Path Reconstruction ........................... 52 4.3.1 Bias and gain error ............................ 52 4.3.2 Position error ............................... 53 4.3.3 Measurement and process noise ..................... 53 4.3.4 Kalman Filter ............................... 53 4.4 A–priori values acquisition ............................ 57 4.4.1 Tornado .................................. 57 4.4.2 AVL .................................... 58 4.4.3 Datcom .................................. 58 4.5 Estimation methods ............................... 58 4.5.1 Equation Error Method ......................... 59 4.5.2 Output Error Method .......................... 62 4.5.3 Recursive Least–Squares ......................... 66 4.5.4 Other approaches ............................. 67 5Experimenalresults 68 5.1 Research airplane ................................. 68 5.1.1 Description of the airplane ........................ 68 5.1.2 Flight envelope .............................. 70 5.1.3 Airplane’s center of mass ........................ 71 5.2 Instrumentation .................................. 72 5.2.1 Data Acquisition System ......................... 72 5.2.2 Utilized sensors .............................. 73 5.2.3 Primary Flight Display .......................... 76 5.3 Flight data acquisition and preprocessing ................... 78 5.3.1 Dynamic longitudinal stability ..................... 78 5.3.2 Flight campaign ............................. 79 5.3.3 Flight Path Reconstruction ....................... 79 5.4 A–priori data ................................... 81 5.4.1 Tornado software estimates ....................... 81 5.4.2 AVL software estimates ......................... 82 5.4.3 Datcom software estimates ....................... 82 5.5 Parameter estimation ............................... 82 5.5.1 Force parameters ............................. 83 5.5.2 Moment parameters ........................... 85 5.5.3 Model validation ............................. 87 5.6 Summary ..................................... 89 5.6.1 Linear dependency of parameters .................... 89 5.6.2 Simulation and model validation .................... 89 5.6.3 Correction of a–priori values ....................... 89 5.6.4 Comparison with other airplane category ................ 90 6 Conclusion and future work 92 A Coordinate systems 99 BWGS84model 102 2 C ICAO Standard atmosphere 103 DAircraftregulatoryauthorities 104 EEASAclassificationofaircraft 105 FAirplanestructuredescription 107 GAdditionalresultsofmodelvalidation 109 H Model of an F–18 Hornet 116 3 List of Figures 2.1 Airplane as a system ............................... 18 3.1 Earth–related reference frames ......................... 21 3.2 Aircraft–related reference frames ........................ 22 3.3 Dataflow diagram of a nonlinear system .................... 36 3.4 Dataflow diagram of a linear State–Space model ................ 41 4.1 Identification process flow ............................ 45 4.2 Input maneuver examples ............................ 46 4.3 Dataflow diagram of a discrete state–space model ............... 55 4.4 Estimation methods categorization ....................... 59 4.5 Block diagram of the EEM ........................... 61 4.6 Block diagram of the OEM ........................... 64 5.1 Photography of the experimental airplane ................... 68 5.2 Operational flight envelope ........................... 70 5.3 Data Acquisition System with sensors and PFD ................ 72 5.4 The NI CompactRIO modules .......................... 74 5.5 Xsens MTi-G Attitude and Heading Reference