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The Future

DAVE-ML

DAVE-ML

  • What it is
  • What it looks like
  • What it isn't
  • What we can do today
  • Why use it?
  • Where we're going
  • How we got here

On 22 March 2011, the draft AIAA standard receives final publication approval by the American National Standards Institute (ANSI)

2011

Simple One-Dimensional Function Table

<?xml version="1.0" standalone="no"?>

<!DOCTYPE DAVEfunc PUBLIC "-//NASA//DTD for Flight Dynamic Models - Functions 1.9//EN" "DAVEfunc.dtd">

<!-- $Revision: 140 $ -->

<DAVEfunc>

<fileHeader>

<author name="Bruce Jackson" org="NASA Langley Research Center" email="e.b.jackson@nasa.gov"/>

<fileCreationDate date="2002-03-11"/>

<description>

Coefficient of lift (non-dimensional) versus angle-of-attack, deg.

Example file for DAVE function table format. This example is the simplest version.

</description>

<modificationRecord modID="A" date="2002-03-11">

<author name="Bruce Jackson" org="NASA Langley Research Center" email="e.b.jackson@nasa.gov"/>

<description>

Added varID to dependentVarPts and independentVarPts, per DTD 1.5b2 change. Also changed

author's xns address to e-mail address.

</description>

</modificationRecord>

<modificationRecord modID="B" date="2006-11-17">

<author name="Bruce Jackson" org="NASA Langley Research Center" email="e.b.jackson@nasa.gov"/>

<description>

Added date to modificationRecord per DTD 1.9 change.

</description>

</modificationRecord>

</fileHeader>

<variableDef name="alpha" varID="alpdeg" units="deg"/>

<variableDef name="CL" varID="cl" units=""/>

<function name="CL">

<independentVarPts varID="alpdeg">

-4.0, 0., 4.0, 8.0, 12.0, 16.0

</independentVarPts>

<dependentVarPts varID="cl">

0.0, 0.2, 0.4, 0.8, 1.0, 1.2

</dependentVarPts>

</function>

</DAVEfunc>

DAVE-ML DTD 2.0 Release Candidate 3

The "PDF" of air vehicle simulations

2010

DAVE-ML and AIAA / ANSI Standard Development

ANSI notice of project initiation is published in the ANSI Standards Action bulletin; the draft AIAA standard (BSR/AIAA S-119) is released for comment

2009

brent@artsimmagic.com

Brent W. York

ArtSimMagic Inc.

2008

A draft document is submitted to the AIAA Committee on Standards

2007

2006

limited in scope, but still evolving

DAVE-ML isn't...

a simulation framework

supported by an enthusiastic user / developer community

Data with Confidence

a complete end product capable of representing an entire flight dynamics model

a methodology to encourage "best practice" for simulation maintainability

Function Declaration

with Provenance

The AIAA Modeling & Simulation Technical Committee's Standards subcommittee begins the effort to establish DAVE-ML as an AIAA (and thereby, ANSI) standard

Breakpoints

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<!DOCTYPE DAVEfunc PUBLIC "-//NASA//DTD for Flight Dynamic Models - Functions 1.9//EN" "DAVEfunc.dtd">

<DAVEfunc>

<fileHeader>

<author name="Bruce Jackson" org="NASA Langley Research Center" email="e.b.jackson@nasa.gov"/>

<fileCreationDate date="2002-03-01"/>

<fileVersion>$Revision: 140 $</fileVersion>

<description> Coefficient of lift (non-dimensional) - single two-dimensional table. Example file

for DAVE function table format. This example is more complex. </description>

<reference refID="REF01" author="Raney, David L." title="F-19A Basic Aerodynamics Model"

accession="NASA TM-4302" date="1992-07-31"/>

<reference refID="REF02" author="Buggati, Richard W." title="F-19A Rotary Aerodynamics Model"

accession="NASA TM-4303" date="1993-07-31"

xlink:href="http://dcb.larc.nasa.gov/models/tm4303.pdf"/>

<reference refID="REF03" author="Aviation Leak &amp; Space Tautology"

title="F-19A Falling Short on Design Performance Numbers" accession="Vol. 45, Number 12"

date="1993-07-03"/>

<modificationRecord modID="A" refID="REF03" date="2002-03-01">

<author name="Hildrup, Bruce L." org="SAID Patuxent River">

<address>

1087 Exploration Parkway Ste 201

Lexington Park, MD 20654

</address>

</author>

<description> Reversed sign on drag term for better performance! </description>

</modificationRecord>

<modificationRecord modID="B" date="2006-11-16">

<author name="Bruce Jackson" org="NASA Langley Research Center" email="e.b.jackson@nasa.gov">

<address>

MS308 NASA

Hampton VA 23681 USA

</address>

</author>

<description> Renamed from .xml to .dml; changed to conform to DAVEfunc.dtd 1.9: added 'date'

to modification record, renamed docID attribute in documentRefs to refID; corrected date

formats to ISO; added fileVersion element with Revision keyword.</description>

</modificationRecord> </fileHeader>

<!-- ================== -->

<!-- Input variables -->

<!-- ================== -->

<variableDef name="alpha" varID="ALPHA" units="deg" symbol="#x3B1">

<description> Instantaneous true angle-of-attack, in degrees </description>

</variableDef>

<variableDef name="Mach" varID="MACH" units="ND" symbol="M"/>

<!-- ================== -->

<!-- Output variable -->

<!-- ================== -->

<variableDef name="CL" varID="CL" units="ND" symbol="CL">

<description> Coefficient of lift based on alpha and mach. </description>

</variableDef>

<!-- ================== -->

<!-- Breakpoint values -->

<!-- ================== -->

<breakpointDef name="alpha" bpID="ALPHA1" units="deg">

<description> Alpha breakpoints for most basic aero data </description>

<bpVals> -4.0, 0., 4.0, 8.0, 12.0, 16.0 </bpVals>

</breakpointDef>

<breakpointDef name="mach" bpID="MACH1" units="ND">

<bpVals> 0.0, 0.4, 0.8, 0.9, 0.95, 0.99, 1.00, 1.01, 1.05, 1.2 </bpVals>

</breakpointDef>

<!-- ================== -->

<!-- Functions -->

<!-- ================== -->

<function name="Basic CL">

<description> Basic coefficient of lift table as a function of Mach and angle of attack </description>

<provenance>

<author name="Bruce Jackson" org="NASA Langley Research Center" xns="@bjax"/>

<functionCreationDate date="Jul-1994"/>

<documentRef refID="REF01"/>

<documentRef refID="REF02"/>

<modificationRef modID="A"/>

</provenance>

<independentVarRef varID="MACH" min="0.3" max="0.95" extrapolate="max"/>

<!-- Mach breakpoints -->

<independentVarRef varID="ALPHA" min="0.0" max="15.0" extrapolate="both"/>

<!-- Alpha breakpoints -->

<dependentVarRef varID="CL"/>

<functionDefn name="CL_FN">

<griddedTable name="CL_TABLE">

<breakpointRefs>

<bpRef bpID="MACH1"/>

<bpRef bpID="ALPHA1"/>

</breakpointRefs>

<confidenceBound value="95%"/>

<dataTable>

<!-- Note: last breakpoint changes most rapidly --> 9.5013e-01 6.1543e-01 5.7891e-02

1.5274e-02 8.3812e-01 1.9343e-01 2.3114e-01 7.9194e-01 3.5287e-01 7.4679e-01 1.9640e-02

6.8222e-01 6.0684e-01 9.2181e-01 8.1317e-01 4.4510e-01 6.8128e-01 3.0276e-01 4.8598e-01

7.3821e-01 9.8613e-03 9.3181e-01 3.7948e-01 5.4167e-01 8.9130e-01 1.7627e-01 1.3889e-01

4.6599e-01 8.3180e-01 1.5087e-01 7.6210e-01 4.0571e-01 2.0277e-01 4.1865e-01 5.0281e-01

6.9790e-01 4.5647e-01 9.3547e-01 1.9872e-01 8.4622e-01 7.0947e-01 3.7837e-01 1.8504e-02

9.1690e-01 6.0379e-01 5.2515e-01 4.2889e-01 8.6001e-01 8.2141e-01 4.1027e-01 2.7219e-01

2.0265e-01 3.0462e-01 8.5366e-01 4.4470e-01 8.9365e-01 1.9881e-01 6.7214e-01 1.8965e-01

5.9356e-01 </dataTable>

</griddedTable>

</functionDefn>

</function>

</DAVEfunc>

Output Variables

Input Variables

the solution to all model exchange problems

2005

Modification Record

a programming-language agnostic implementation of the recently approved

AIAA / ANSI flight dynamics model exchange standard

Two-Dimensional Orthogonal Table

Data Source

required to be used by any agency (yet)

defined using a Document Type Definition (DTD) for XML

finished

the Dynamic Aerospace Vehicle Exchange Markup Language

DAVE-ML is...

"The ultimate goal is to drastically reduce the amount of time required to move an operating, real-time simulation model from one simulation laboratory to another from weeks/months to less than one work day."

Jackson, Hildreth, York, and Cleveland present an AIAA paper detailing the successes and challenges of the demonstration

2004

Current Limitations

"...estimated savings of $6.8M per year for a single in-service tactical aircraft program..."

"The purpose of DAVE-ML is to provide a digital exchange format for aerospace vehicle flight dynamic models in a facility- and programming-language-neutral way, using open standards."

  • ironically, no dynamics are currently supported
  • nothing that has a state (integrators, etc.) can be represented
  • complex control laws currently cannot be modeled

Version 2.0.1 of the DAVE-ML DTD supports any static, non-linear model (such as aerostatics, steady engine thrust, and mass properties)

NASA Ames, NASA Langley, and U.S. Navy (Pax River) agree to develop and demonstrate ability to exchange flight models in DAVE-ML

2003

Bruce Jackson and Bruce Hildreth propose DAVE-ML in a paper to the AIAA (American Institute of Aeronautics & Astronautics)

2002

DAVE-ML DTD 1.4

DAVE-ML v4.0

Questions?

DAVE-ML v3.0

DAVE-ML v2.3

Eight Months to Eight Minutes

DAVE-ML v2.2

  • Documentation, checkcases, uncertainty, and provenance packaged with data / model

DAVE-ML v2.1

Further element refinements

Usability improvements

Addressing community feedback

Multidimensional output tables

Vector and matrix support

Subsystems (ability to build libraries)

Current Capabilities

Dynamic model support

(1) international standard for data encoding

(2) universally transportable

(3) human- and machine-readable

(4) self-documenting

(5) can be easily transformed into a variety of other formats using XSLT technology

Design Decisions

XML is a formal standard supported by the World-Wide Web Consortium (W3C) with many advantages for use in DAVE-ML:

  • Clarity over brevity
  • XML as transport
  • non-linear function descriptions
  • links to on-line documentation
  • citations to off-line documentation
  • data provenance (original source and modification history)
  • buildup equations of arbitrary complexity, including switching between databases
  • embedded check-case data, including all intermediate calculations
  • embedded data uncertainty descriptions

System-of-systems support

(true encapsulation of total dynamic vehicle model)

Off-line

DAVEtools

Developed by NASA Langley (Bruce Jackson)

Java tools for manipulating DAVE-ML files

Can generate MATLAB and Simulink objects from DAVE-ML

daveml.org/DAVEtools/index.html

"Real-World" Examples

Off-line

XSLT

eXtensible Stylesheet Language Transformation: standard translation protocol for XML files

  • DAVE-ML website (daveml.org)
  • sim-stds mailing list (daveml.org/list.html)
  • Flight Dynamics Model Exchange Standard (ANSI/AIAA S-119-2011e) available from aiaa.org (free for AIAA members)

Uses a utility such as Xalan (xml.apache.org/xalan-j/)

Resources

Allows user to transform DAVE-ML into any other arbitrary format (HTML, PDF, proprietary function table lookup data file format)

F-16 Fighter Aircraft

  • 51 variables, 18 tables, 744 points
  • Switches & absolute-value nonlinear elements
  • 17 verification check-cases included
  • 154 KB file with 2,712 lines

Tools

Example at daveml.org/tools.html

Run-time

These "Real-World" Examples have been successfully read and executed by multiple organizations.

Janus C++ API

Developed by Australian Defence Science and Technology Organisation (DSTO)

Built on Apache Xerces-C++ validating XML parser library

www.dsto.defence.gov.au/research/4675/

  • Supersonic and subsonic regimes
  • 361 variables, 168 tables, 6,240 points
  • 25 verification check-cases included
  • 1.2 MB file with 22,299 lines

HL-20 Lifting Body

Off-line

GeneSim

Open Source project (development may currently be stalled)

Auto-generates C code from DAVE-ML input files

genesim.sourceforge.net

Available on DAVE-ML website

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