Progress in the Migration of Flight Test Analysis Routines to Python

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Stella Jackson
5 years ago
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1 Progress in the Migration of Flight Test Analysis Routines to Python

Previous presentation at 2016 Instrumentation Workshop introduced Python as a MATLAB alternative for flight test Projections from 2016: Introduction We can and should migrate our MATLAB test and

2 Previous presentation at 2016 Instrumentation Workshop introduced Python as a MATLAB alternative for flight test Projections from 2016: Introduction We can and should migrate our MATLAB test and analysis routines to Python All analysis routines in the core code of IADS can easily be translated to Python for development of application-specific tools Discoveries and application-specific tools developed since 2016

3 Python-Specific Discoveries Python 2.X or Python 3.X? MatPlotLib Python Library for graphics The TKinter Python Library for graphics Anaconda Distribution and the mpldatacursor Library example Ability to produce a distributable package from Python code Cuda/Numba - brand new topic not in use yet

4 CIC filter compensator coefficients provided by user IADS did not have FIR filter implementation COM DLL was developed for FIR Filter Implementation Filter Tools

FIR Filter Designer was developed in Python to allow users to take advantage of the new FIR filter implementation Export filter coefficients to

5 FIR Filter Designer was developed in Python to allow users to take advantage of the new FIR filter implementation Export filter coefficients to file for immediate use in IADS Linear phase in passband is desirable for certain analyses Interactive (TKinter library) Filter Tools (continued)

Filter Tools (continued) IIR Filter Designer was developed in Python to compliment FIR Filter Designer and replace legacy IIR Filter Designer Elliptic coefficient algorithm from IADS was

6 Filter Tools (continued) IIR Filter Designer was developed in Python to compliment FIR Filter Designer and replace legacy IIR Filter Designer Elliptic coefficient algorithm from IADS was translated and used Includes features missing in the original tool (impulse/step response and bandstop filters) Interactive (TKinter library) zoom and selection capabilities and data exports

upgraded easily by users Not yet interactive can be

7 Modal Analysis Widgets Mode Indicator Function (MIF) Tool prototyped in Python Simple math can be upgraded easily by users Not yet interactive can be imbedded in a tkinter Frame like Filter Designer Missed one!

Modal Analysis Widgets (continued) Stabilization Diagram prototype developed in Python Uses Rational Fraction Polynomial curve fit method from IADS (translated)

8 Modal Analysis Widgets (continued) Stabilization Diagram prototype developed in Python Uses Rational Fraction Polynomial curve fit method from IADS (translated) Reads frequency response data from standard IADS Log To File output Also not yet interactive frequency limits, maximum order and tolerances are hard-coded in the script

9 PYADS a Simpler Python IDE Experience with Anaconda s Spyder IDE prompted the development of a simpler IDE optimized for easier debugging of Scientific Python scripts - Contents of arrays can be displayed while stepping through code - Hovering over variables displays their value - Call stack, variable watch window, Step in function and breakpoints follow Visual Studio convention PYADS is still in development/test input welcomed

10 PYADS Screen Shot A few steps after a breakpoint

11 Ongoing Research OpenModal - experimental modal analysis software in Python NeXT/ERA, a technique used in operational structural analysis, can be realized in Python Improved Filtering using filtfilt() in SciPy library can probably be used for many IADS analyses, particularly in post-test, near real-time and frequency domain displays Python Simulink clones are starting to appear

12 OpenModal The source code for this tool is available for download may be able to adapt some of this for flight test Build UUT geometry (sensor locations on a 2D or 3D model) Measure or Import Data System ID (curve fitting) Mode shape animation

13 Natural Excitation Technique and ERA NeXT estimate modal parameters from only operational data Produce state space model from cross correlations Extract modal parameters from state space model Will this work? Need to simulate a data set Get algorithm working with sim data Build feature-rich Python GUI that can animate mode shapes

14 Improved Filtering Techniques SciPy library has filtfilt() function (forward/backward filtering) This can be used in many IADS algorithms that average blocks Initial conditions specification may mitigate impulse response Research done in Python does not disturb core code of IADS Incorporate filtfilt() directly into some of IADS analyses?

BMSpy - Block model simulator designed as a lightweight, fully scriptable, open-source equivalent to Simulink in python PySimLib to simulate Modelica Simulink models in a

15 BMSpy - Block model simulator designed as a lightweight, fully scriptable, open-source equivalent to Simulink in python PySimLib to simulate Modelica Simulink models in a platform-independent way PyLinX screenshot looks like they are on the right track Python Simulink Clones No experience with these tools yet, but they don t appear to be as far along as Xcos (SciLab)

Closing Remarks Tools and widgets have been successfully developed in Python since the previous presentation that can be easily distributed to the IADS user community PYADS will be optimized

16 Closing Remarks Tools and widgets have been successfully developed in Python since the previous presentation that can be easily distributed to the IADS user community PYADS will be optimized for IADS users (deployed as a distribution) Mode shape animation in near real-time, a Holy Grail in our list of future capabilities, is within striking distance Scientific Python is here to stay

17 Contact Information For further information regarding IADS contact: Patrick Mattingly Vice President SYMVIONICS, Inc. (661) x206 Commercially available product. Numerous contracting options are available to procure IADS, including GSA contracting vehicles. For more information about SYMVIONICS, see our web site or contact: Richard A. Weeks Executive Vice President SYMVIONICS, Inc. (626)

Can We Migrate Our Analysis Routines to Python?

Can We Migrate Our Analysis Routines to Python? Introduction Can we migrate our analysis routines to Python? - MATLAB is powerful, but it s expensive. - Capable open-source alternatives exist and are thriving.