Software for Flight Vehicle System IdentificationESTIMA / FITLAB / FVSysID at DLR Dr. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/1 Aug. Dr. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. 2006 Software/2 .This page is left intentionally blank. MD (Dennis Linse) Software packages used at Aerospace industries are not included: Boeing. California. CA (Richard Maine and Ken Iliff) pEst: Parameter Estimation (1987) interactive parameter estimation for nonlinear dynamic systems. Aug. Edwards. ….Overview of Software Tools (1) MMLE3: Modified Maximum Likelihood Estimation: A general Fortran program for Maximum Likelihood Parameter Estimation (1980) NASA Dryden. DLR Institute of Flight Systems. NASA. 2006 Software/3 . Germany (Ravindra Jategaonkar) IDEAS: Integrated Data Evaluation and Analysis System (1998) Science Applications International Corporation. Ames/Dryden (James Murray and Richard Maine) ESTIMA: Integrated Software tool for parameter estimation (1983 / 1998) and simulation of dynamic systems. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain.. Braunschweig. Embraer. Airbus. Dr. Langley. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. Germany (Susanne Weiss) FVSysID Flight Vehicle System IDentification: A Time Domain Methodology.HQ analysis. Germany FITLAB Matlab Tools box for parameter estimation in frequency domain – Linear systems DLR Institute of Flight Systems. 2006 Software/4 . Aug. Braunschweig. Braunschweig. NASA Ames DIVA MIMO Analysis and Transfer function approximations DLR Institute of Flight Systems. Spectral signal analysis.Overview of Software Tools (2) MATLAB based software packages: SIDPAC: System Identification Programs for AirCraft (2002) NASA. VA (Gene Morelli) FITLAB Tools box for Linear and Nonlinear parameter estimation (2001) DLR Institute of Flight Systems. Germany (Susanne Weiss) Dr. (Author: Ravindra Jategaonkar) 2006. AIAA Book Frequency Domain CIFER: Comprehensive Identification from FrEquency Responses Identification of transfer-function models. Braunschweig. Mark Tischler. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain.Developed using basic Matlab (No special Toolbox required) .Recursive algorithms: .FVSysID: Matlab based software (1) Part of AIAA Book: “Flight Vehicle System Identification: A Time Domain Methodology” Specially tailored software for system identification in time domain .Off-line algorithms: .Recursive least squares (RLS) . Aug.Fourier transform regression (FTR) .Applicable to any general linear / Nonlinear dynamic system . 2006 Software/5 .Output Error Method (Linear / Nonlinear systems) .Chapter wise sorted .Provides sample flight data .Provides source codes (m-files of all the methods / functions) .Multiple run evaluation .Filter Error Method (Linear / Nonlinear systems) .Extended / Unscented Kalman filters (EKF / UKF) Dr. LS. UKF . β y ] Dr. flight data.obser_eq Î function to code observation equations y (t ) = g[ x(t ). EKF. initial values etc.m Î Definition of model.Stabilized OEM .Differentiation of measured variables (multiple run) . 3rd. 2006 Software/6 . β x ] . 4th order) . FEM.Integration method (Runge-Kutta 2nd. β x .Eigenvalue transformation .Smoothing / Filtering of measured data (multiple runs) USER Interface . Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain.mDefCasexx.state_eq Î function to code rhs of state equations x& (t ) = f [ x(t ).Unstable aircraft: . . Aug. TLS. u (t ).Equation Decoupling .FVSysID: Matlab based software (2) AIAA Book: “Flight Vehicle System Identification: A Time Domain Methodology” .Utility programs . u (t ). Ravindra Jategaonkar C X = C L sin α − C D cos α C Z = − C L cos α − C D sin α AIAA Short Course: Flight Vehicle System Identification in Time Domain. Aug. 2006 Software/7 . pitching moment Derivatives State equations F qS C D + g sin(α − θ ) + e cos(α + σ T ) V& = − m m F qS g C L + q + cos(α − θ ) − e sin(α + σ T ) α& = − V mV mV θ& = q q& = F q Sc C m + e ( l tx sin σ T + l tz cos σ T ) Iy Iy Observation equations C D = C D 0 + C DV C L = C L0 + C LV V + C Dα α V0 V + C Lα α V0 Cm = Cm 0 + CmV V qc + Cmα α + Cmq + Cmδe δ e 2Vo V0 Vm = V αm = α θm = θ qm = q q& m = F q Sc C m + e ( l tx sin σ T + l tz cos σ T ) Iy Iy F qS C X + e cos σ T m m F qS C Z − e sin σ T = m m a xm = a zm Dr.FVSysID: Matlab based software (3) AIAA Book: “Flight Vehicle System Identification: A Time Domain Methodology” Example: Estimation of lift. drag. Aug. pitching moment Derivatives The unknown parameter vector Θ = [C D0 C DV C Dα C L0 C LV C Lα C m0 C mV C mα C mq C mδe ]T V . % Number of states Ny = 7. % Number of system parameters Dr. q. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. Equations: ‘obs_TC04_hfb_lon’ δ e . q States: State equation: ‘xdot_TC04_hfb_lon’ Observations: V . 2006 Software/8 . a x . % function for observation equations Nx = 4. % function for state equations See m-files obser_eq = ‘obs_TC04_hfb_lon’. α. Fe Inputs: test_case = 4. % Number of observation variables Nu = 2. state_eq % Integer flag for the test case = ‘xdot_TC04_hfb_lon’. θ .θ. % Number of input (control) variables NparSys = 11. q& .FVSysID: Matlab based software (4) AIAA Book: “Flight Vehicle System Identification: A Time Domain Methodology” Example: Estimation of lift. a z Obs. α . drag. Aug. UKFaug) /FVSysID/chapter07/ mainRPE: test_case = 4 Several test cases and sample flight data provided Dr.FVSysID: Matlab based software (5) AIAA Book: “Flight Vehicle System Identification: A Time Domain Methodology” Example: Estimation of lift. drag. pitching moment Derivatives Run the test case: Output Error method: /FVSysID/chapter04/ ml_oem: test_case = 4 Filter Error method /FVSysID/chapter05/ ml_fem: test_case = 4 Recursive estimation methods (EKF. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. 2006 Software/9 . UKF. of concurrent user - Industry. Research org. Linux CONPLOT: Convergence plots PSDPLOT: Power spectral density Graphic: Gnuplot/GV or GINO Licensed software: - No.. standard deviation. Log file: estimates. Lat.. Ravindra Jategaonkar Support: Demo programs. Aug. SysID... correlation. Plot programs (Common to all platforms) Post processing (time and frequency domain) Eigenvalues/vectors Commercial aspects Availability: Four platforms - IBM-AIX. . short courses EIGPLOT: Eigenvalues/vectors BODEPLOT: Frequency response AIAA Short Course: Flight Vehicle System Identification in Time Domain. THPLOT: Time history plots CRSPLOT: Cross plots Time histories: cdf. Ascii Convergence Linearized system Common environment Front end and command procedures Scripts: Utility... estimation and simulation Modeling Standard models User models (FPR. 6DOF. 2006 Software/10 ./Univs. Lon. Initial familiarization. SunOS-Solaris. 2nd) (completely flexible) Flight Data CDF or ASCII Online interactive mode with graphical display Results Nucleus Sys Id and simulation 7 Optimization methods 6 Integration formulas Large scale systems . Completely configurable Unix / X-windows based "xfiles" Dr. SG-IRIX.ESTIMA (1) Integrated Software Tool for System Identification and Simulation of Dynamic Systems Modeling. ESTIMA (2) Front End Command procedures Scripts: Utility. Plot programs (Common to all platforms) Completely configurable Unix / X-windows based "xfiles" Dr. SysID. Aug. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. 2006 Software/11 . Lat. Aug. Ascii Convergence Linearized system Common environment Eigenvalues/vectors AIAA Short Course: Flight Vehicle System Identification in Time Domain... . standard deviation.. 2nd) (completely flexible) Flight Data CDF or ASCII Online interactive mode with graphical display Dr. Lon. Ravindra Jategaonkar Results Nucleus Sys Id and simulation 7 Optimization methods 6 Integration formulas Large scale systems . correlation. Time histories: cdf...ESTIMA (3) Core Modeling. Log file: estimates. 6DOF. estimation and simulation Modeling Standard models User models (FPR. 2006 Software/12 .. δ4... Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. δ3. φ. δr. β. Lat. r. δf.. Aug. Observations: ay. 6DOF. 2nd) (completely flexible) Program control file Channel Nos. ψ. ψ. φ. p. for input and output variables A/c mass characteristics Aerodynamic parameters Keyword: mod_sub = lat State variables: p. ayc CY = CY 0 + CYβ β + CYp p + CYr r + CY δ a δ a + CY δ r δr + CYδ 3 δ3 + CYδ 4 δ 4 C =C +C β +C p +C r +C δ +C δ +C δ +C δ l l0 lβ lp lr l δ a a l δ r r lδ 3 3 lδ 4 4 Fixed structure Control via Input file C =C + C β + C p +C r + C β& + C δ + C δ + C δ + C δ n n0 nβ np nr nδ a a nδ r r nδ3 3 nδ 4 4 nβ& Dr. Lon. v Control inputs: δa. 2006 Software/13 .ESTIMA (4) User Interface Models Modeling Standard models User models (FPR. . r. ..ESTIMA (5) Algorithmic Features Nucleus Sys Id and simulation 7 Optimization methods 6 Integration formulas Large scale systems . 60 inputs. Backward differentiation formula 80 time slices. Output error method Optimization Methods Unconstrained Gauss-Newton Bounded-Variable Gauss-Newton Levenberg-Marquardt Jacob's Heuristic search EXTREM Conjugate directions POWELL SIMPLEX (Nelder and Mead) SUBPLEX (ROWAN) Integration Methods Hybridization Euler Runge-Kutta 2nd order of optimization and Integration methods Runge-Kutta 3rd order Runge-Kutta 4th order Large scale systems Runge-Kutta-Fehlberg with step size control 30 States. 2006 Software/14 .. 80000 data points Dr.. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. Aug. 60 outputs. 2006 Software/15 . Aug. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain.FITLAB: Toolbox for Sys ID under MATLAB (1) FITLAB – Features & Functionality Matlab® Toolbox Identification of nonlinear models – m-Files – Simulink®-Models – S-Functions Identification of linear models – time and frequency domain – startup algorithm Maximum-Likelihood cost function Optimization using – bounded Gauss-Newton method – subspace-simplex search method Multiple maneuvers can be evaluated together Graphical user interface Dr. Aug. 2006 Software/16 .FITLAB: Toolbox for Sys ID under MATLAB (2) FITLAB GUI – Graphical User Interface Menu-driven system identification Operation via mouse Standard plots – quicklook plots for measured data – report plots for results Restart option Generation of batch files for repeating tasks Dr. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. 2006. V. R. Weiss. Vol. V. NASA CP-3226.cfm?pageid=360&id=1447 Jategaonkar. E. “Aircraft System Identification Using Integrated Software Tools”. Aug. Maine. DLR IB 111-2001/29. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. “ESTIMA: A Modular and Integrated Software Tool for Parameter Estimation and Simulation of Dynamic Systems .. 2006 Software/17 .. Version 1. NASA TM-88280... August 2002.aiaa.. M.0”. RTO-MP-11. E. Nov.org/content. Aug. Volume 216. March 1999.2 – Comprehensive Identification from Frequency Responses”. A. Jategaonkar. 1994. S.. Sept. Flight Vehicle System Identification: A Time Domain Methodology. 2002. and Maine.User’s Manual. Issue 8. AIAA Paper 2002-4704. 1980. E. Sept.. Murray. 1987. R. “User’s Manual for MMLE3. and Thielecke. “ Dr. Dec. J. a general FORTRAN Program for Maximum Likelihood Estimation”. K. Journal of Aerospace Science and Technology. ISBN: 1-56347-836-6 http://www. D. 6. Tischler. July 2001. “ESTIMA .565-578. Linse. Paper 11. “CIFER version 2. E. F. VA. pp.an Integrated Software Tool for Nonlinear Parameter Estimation“. B.References Jategaonkar. W. J.1 User’s Manual”. Morelli. R. AIAA Progress in Astronautics and Aeronautics Series Published by AIAA Reston. R. R. V. “System Identification Programs for AirCraft (SIDPAC)”. and Iliff.. NASA TP-1563. “The pEst Version 2.. Aug. Dr. Ravindra Jategaonkar AIAA Short Course: Flight Vehicle System Identification in Time Domain. 2006 Software/18 .This page is left intentionally blank.