AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/1Dr. Ravindra Jategaonkar

Software for Flight Vehicle System Identification

ESTIMA / FITLAB / FVSysIDat DLR

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/2Dr. Ravindra Jategaonkar

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AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/3Dr. Ravindra Jategaonkar

MMLE3: Modified Maximum Likelihood Estimation: A general Fortran program for Maximum Likelihood Parameter Estimation (1980)NASA Dryden, Edwards, CA (Richard Maine and Ken Iliff)

pEst: Parameter Estimation (1987)interactive parameter estimation for nonlinear dynamic systems.NASA, Ames/Dryden (James Murray and Richard Maine)

ESTIMA: Integrated Software tool for parameter estimation (1983 / 1998) and simulation of dynamic systems.DLR Institute of Flight Systems, Braunschweig, Germany (Ravindra Jategaonkar)

IDEAS: Integrated Data Evaluation and Analysis System (1998)Science Applications International Corporation, California, MD (Dennis Linse)

Overview of Software Tools (1)

Software packages used at Aerospace industries are not included:Boeing, Airbus, Embraer, ..

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/4Dr. Ravindra Jategaonkar

MATLAB based software packages:SIDPAC: System Identification Programs for AirCraft (2002)

NASA, Langley, VA (Gene Morelli)

FITLAB Tools box for Linear and Nonlinear parameter estimation (2001)DLR Institute of Flight Systems, Braunschweig, Germany (Susanne Weiss)

FVSysID Flight Vehicle System IDentification: A Time Domain Methodology.(Author: Ravindra Jategaonkar) 2006, AIAA Book

Frequency DomainCIFER: Comprehensive Identification from FrEquency Responses

Identification of transfer-function models, Spectral signal analysis,HQ analysis.Mark Tischler, NASA Ames

DIVA MIMO Analysis and Transfer function approximationsDLR Institute of Flight Systems, Braunschweig, Germany

FITLAB Matlab Tools box for parameter estimation in frequency domain Linear systemsDLR Institute of Flight Systems, Braunschweig, Germany (Susanne Weiss)

Overview of Software Tools (2)

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/5Dr. Ravindra Jategaonkar

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- Developed using basic Matlab (No special Toolbox required)

- Provides source codes (m-files of all the methods / functions)

- Provides sample flight data

- Chapter wise sorted

- Applicable to any general linear / Nonlinear dynamic system- Multiple run evaluation

- Off-line algorithms:- Output Error Method (Linear / Nonlinear systems)

- Filter Error Method (Linear / Nonlinear systems)

- Recursive algorithms:- Recursive least squares (RLS)

- Fourier transform regression (FTR)

- Extended / Unscented Kalman filters (EKF / UKF)

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/6Dr. Ravindra Jategaonkar

FVSysID: Matlab based software (2)

AIAA Book: Flight Vehicle System Identification: A Time Domain Methodology

- Unstable aircraft:- LS, TLS, FEM, EKF, UKF- Stabilized OEM- Eigenvalue transformation- Equation Decoupling

- Utility programs- Integration method (Runge-Kutta 2nd, 3rd, 4th order)- Differentiation of measured variables (multiple run)- Smoothing / Filtering of measured data (multiple runs)

USER Interface

- mDefCasexx.m Definition of model, flight data, initial values etc.- state_eq function to code rhs of state equations- obser_eq function to code observation equations

]),(),([)( xtutxftx =&],),(),([)( yxtutxgty =

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/7Dr. Ravindra Jategaonkar

FVSysID: Matlab based software (3)

AIAA Book: Flight Vehicle System Identification: A Time Domain Methodology

Example: Estimation of lift, drag, pitching moment Derivatives

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AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/8Dr. Ravindra Jategaonkar

FVSysID: Matlab based software (4)

AIAA Book: Flight Vehicle System Identification: A Time Domain Methodology

Example: Estimation of lift, drag, pitching moment Derivatives

The unknown parameter vector

TemmqmmVmLLVLDDVD CCCCCCCCCCC ][ 000 =

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States: State equation: xdot_TC04_hfb_lon

Observations: Obs. Equations: obs_TC04_hfb_lon

Inputs:

test_case = 4; % Integer flag for the test casestate_eq = xdot_TC04_hfb_lon; % function for state equations obser_eq = obs_TC04_hfb_lon; % function for observation equationsNx = 4; % Number of states Ny = 7; % Number of observation variablesNu = 2; % Number of input (control) variablesNparSys = 11; % Number of system parameters

See m-files

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/9Dr. Ravindra Jategaonkar

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, UKF, UKFaug)/FVSysID/chapter07/mainRPE: test_case = 4

Several test cases and sample flight data provided

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/10Dr. Ravindra Jategaonkar

Integrated Software Tool forSystem Identification and Simulation of Dynamic Systems

Standardmodels(FPR,Lon,Lat,6DOF,2nd)

ModelingUsermodels

(completely flexible)

Commonenvironment

Sys Id andsimulation7Optimization methods6IntegrationformulasLargescale systems.....

Nucleus

Results

Modeling, estimation and simulation

Onlineinteractivemode withgraphicaldisplay

Flight DataCDFor

ASCII

Logfile:estimates,correlation,standard deviation,...

Timehistories:cdf,Ascii

Convergence

Linearized system

Eigenvalues/vectors

Scripts:Utility,SysID,Plotprograms(Commontoallplatforms)

CompletelyconfigurableUnix/X-windowsbased

"xfiles"

Front end and command proceduresAvailability:Fourplatforms-IBM-AIX,SG-IRIX,SunOS-Solaris,Linux

Graphic:Gnuplot/GVorGINO

Licensed software:-No.ofconcurrentuser-Industry,Researchorg./Univs.

Support:Demoprograms,Initialfamiliarization,shortcourses

Commercial aspectsCONPLOT:Convergence plots

(time and frequency domain)

EIGPLOT:Eigenvalues/vectors BODEPLOT:Frequency response

THPLOT:Timehistory plots CRSPLOT:Crossplots

Post processing

PSDPLOT:Powerspectral density

ESTIMA (1)

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/11Dr. Ravindra Jategaonkar

Front End

Scripts:Utility,SysID,Plotprograms(Commontoallplatforms)

CompletelyconfigurableUnix/X-windowsbased

"xfiles"

Command procedures

ESTIMA (2)

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/12Dr. Ravindra Jategaonkar

Standardmodels(FPR,Lon,Lat,6DOF,2nd)

ModelingUsermodels

(completely flexible)

Commonenvironment

Sys Id andsimulation7Optimization methods6IntegrationformulasLargescale systems.....

Nucleus

Results

Modeling, estimation and simulation

Onlineinteractivemode withgraphicaldisplay

Flight DataCDFor

ASCII

Logfile:estimates,correlation,standard deviation,...

Timehistories:cdf,Ascii

Convergence

Linearized system

Eigenvalues/vectors

Core

ESTIMA (3)

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/13Dr. Ravindra Jategaonkar

User Interface

ModelingUser models

(completelyflexible)

Models

Standard models(FPR,Lon,Lat,6DOF,2nd)

Statevariables:p, r,, , vControlinputs:a, r, 3, 4, f, ....Observations: ay,,p,r,, , ayc

Keyword: mod_sub = lat

44330 lClCrrlCaalCrlrCplpClClClC +++++++=

44330 nCnCrrnCaanCnCrnrCpnpCnCnCnC ++++++++= &&

44330 YCYCrrYCaaYCrYrCpYpCYCYCYC +++++++=

Fixed structureControl via Input file

Program control fileChannelNos.forinputandoutputvariables

A/cmasscharacteristics

Aerodynamicparameters

ESTIMA (4)

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/14Dr. Ravindra Jategaonkar

Output error method

Optimization MethodsUnconstrainedGauss-NewtonBounded-VariableGauss-NewtonLevenberg-Marquardt

Jacob'sHeuristicsearchEXTREMConjugatedirectionsPOWELL

SIMPLEX(Nelder andMead)SUBPLEX(ROWAN)

Integration MethodsEulerRunge-Kutta 2ndorderRunge-Kutta 3rdorderRunge-Kutta 4thorderRunge-Kutta-Fehlberg withstepsizecontrolBackwarddifferentiationformula

SysIdandsimulation7Optimizationmethods6IntegrationformulasLargescalesystems.....

Nucleus

HybridizationofoptimizationandIntegrationmethods

Large scale systems30States,60outputs,60inputs,80timeslices,80000datapoints

ESTIMA (5)

Algorithmic Features

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/15Dr. Ravindra Jategaonkar

FITLAB: Toolbox for Sys ID under MATLAB (1)

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

FITLAB Features & Functionality

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/16Dr. Ravindra Jategaonkar

FITLAB: Toolbox for Sys ID under MATLAB (2)

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

FITLAB GUI Graphical User Interface

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/17Dr. Ravindra Jategaonkar

ReferencesJategaonkar, R. V., Flight Vehicle System Identification: A Time Domain Methodology,Volume 216, AIAA Progress in Astronautics and Aeronautics SeriesPublished by AIAA Reston, VA, Aug. 2006, ISBN: 1-56347-836-6http://www.aiaa.org/content.cfm?pageid=360&id=1447

Jategaonkar, R. V., ESTIMA: A Modular and Integrated Software Tool for Parameter Estimation andSimulation of Dynamic Systems - Users Manual, Version 1.0, DLR IB 111-2001/29, July 2001.

Jategaonkar, R. V. and Thielecke, F., ESTIMA - an Integrated Software Tool for Nonlinear ParameterEstimation, Journal of Aerospace Science and Technology, Vol. 6, Issue 8, Dec. 2002, pp.565-578.

Linse, D. J., Aircraft System Identification Using Integrated Software Tools, RTO-MP-11, Paper 11, March 1999.

Maine, R. E., and Iliff, K. W., Users Manual for MMLE3, a general FORTRAN Program for Maximum Likelihood Estimation, NASA TP-1563, Nov. 1980.

Murray, J. E. and Maine, R. E., The pEst Version 2.1 Users Manual, NASA TM-88280, Sept. 1987.

Morelli, E. A., System Identification Programs for AirCraft (SIDPAC), AIAA Paper 2002-4704,August 2002.

Tischler, M. B., CIFER version 2.2 Comprehensive Identification from Frequency Responses,NASA CP-3226, Sept. 1994.

Weiss, S.

AIAA Short Course: Flight Vehicle System Identification in Time Domain, Aug. 2006 Software/18Dr. Ravindra Jategaonkar

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