Download - SEDC Conference 2014

PMI Validation and Conformance Testing
for Model-based Engineering
Joshua Lubell
[email protected]
Systems Engineering Conference in Washington DC (SEDC)
April 3, 2014
www.nist.gov/el/msid/infotest/mbe-pmi-validation.cfm
Engineering Laboratory
Systems Integration Division
Outline
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Model-based systems engineering and PMI
PMI standards and “semantic PMI”
NIST digital test artifacts and V&V workflow
Software tools
Future directions
Disclaimer: Any mention of commercial products
within this presentation is for information only; it
does not imply recommendation or endorsement by
NIST.
Model-based SE and PMI
• Model must capture product’s functional and
behavioral requirements
• Product and Manufacturing Information (PMI)
– Specifies these requires in a production context
– In a formal and precise language
– Communicating allowable product geometry
variations in form, size, and orientation
• PMI is essential for manufacturing high-precision
parts and assemblies
PMI Example from a Standard*
1101, Geometrical product specifications (GPS)–geometrical tolerancing–tolerances of
form. Orientation, location and run-out (2nd ed.) International Organization for
Standardization, Geneva (Switzerland) (2004)
*ISO
The Digital Thread
• Model Based Definition (MBD)
– Created by Engineering
– Used to complete Model Based Manufacturing
and Inspection (MBM and MBI)
• DT = MBD data + MBM data + MBI data
• 3D models with “semantic” PMI makes it
possible
Semantic PMI
• Defined using a computer-interpretable language
• Allows software developers to automate various design
and manufacturing functions
• Unambiguous representation and presentation of PMI
are critical for digital product definition
• But PMI standards are complex
• Potential is great for the same PMI to be interpreted
and presented differently by different software
applications
• Incorrect PMI presentation and misinterpretation can
result in significant delays and costly errors
NIST PMI Validation and
Conformance Testing Project
Develop test case definitions, test case models and software
algorithms sufficient to measure conformance of CAD systems to
American Society of Mechanical Engineers (ASME) standards for
PMI.
ASME Y14.5-1994 - Dimensioning and Tolerancing
ASME Y14.41-2003 - Digital Product Data Definition Practices
Project Components (1)
• Test Cases
• Select 50 PMI annotation constructs
(Atomic Test Case – ATC)
• PMI applied to 5 parts (Complex Test Case – CTC)
• Each a collection of 10 ATC
• Expert review of the PMI
• Test Models
• Each of the 5 parts modeled in 4 CAD systems
(CATIA, Creo, NX, SolidWorks)
• Focus on Semantic PMI
• Precise, not graphical, machine interpretable, no
encoded strings
Project Components (2)
• Verification of CAD models
• Comparison to test case definitions and to each other
• Identify and resolve modeling issues to ensure semantic
equivalence
• Test of the CAD authoring system
• Release to implementer groups
• Generate derivative STEP, JT, and 3D PDF files
• Validate derivative files to original CAD models
• Import derivation STEP files to CAD systems
• Validate derivative CAD models to original CAD models
• Test of CAD translating system
• Release test cases and CAD models to public
MBE PMI Validation Data Process Flow
Expert
Review
CATIA V5
Models
CAx-IF
STEP
Files
Creo
Models
Test
Cases
JT-IF
NX
Models
SolidWorks
Models
Verification
JT
Models
CATIA V5
Models
Creo
Models
NX
Models
3D
PDF-IF
3D PDF
Models
Implementer Forum =
Vendor partnership to identify &
resolve implementation issues
SolidWorks
Models
Validation
Test Cases versus Test Models *
Test Case – a PMI construct
*Figures
Test Model – its CAD implementation
from “NIST MBE PMI Validation Project Update,” ITI Transcendata, February 2013
“Complex” versus “Atomic”
5 Complex Test Cases
• Manufacturable
• Useful for integration
testing
• Pre-requisite for developing
Atomic Test Cases
50 Atomic Test Cases
• Many ATCs to one CTC
• Useful for conformance
testing
Sample PMI Annotation Constructs
Complex Test Cases Spreadsheet
Atomic Test Cases Spreadsheet
Test Case Browser Demo
http://cic.nist.gov/mbe/PMITest/index.html
Test Cases Modeled in 4 CAD Systems
Test Case
CATIA V5 R21 Model
NX 8.0 Model
SolidWorks 2012 Model
Creo 2.0 Model
Example Semantic Verification Issue
in-between designation and bounds
(edges) are non-semantic.
• Test Cases
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Results
Select 50 PMI annotation constructs
Applied to 5 parts (10 per part)
Documented with PDF, images, and explanatory text
Expert review of the PMI
• Test Models
• Each of the 5 parts with PMI modeled in 4 CAD
systems
• Verification of CAD models
• Comparison to test case definitions and to each other
• Release to Implementor Forums
• Resolve modeling issues
• Generate derivative STEP, JT files, and 3D PDF files
• Validate derivative files to original CAD models (in
progress)
NIST STEP File Analyzer and
Semantic PMI
• STEP File Analyzer parses ISO 10303 STEP
file and displays PMI data in spreadsheet
• Recreates visual presentation of the
semantic PMI
• Compare to test case definition
• Identify source of discrepancies
• STEP file, CAD model, Analyzer
Semantic PMI Summary Worksheet
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Recreate Visual Presentation of the Semantic PMI
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Datum systems, dimensional and geometric tolerances
STEP File Analyzer - Coverage Analysis
Column A – Types of PMI,
numbers in parentheses refer to
CAx-IF Recommended Practices
Other Columns – One per STEP
file, X indicates the file contains
that type of PMI, but not the
number of instances
• Test Cases
Phase 2 Plans
• Select 50 more PMI annotation constructs (Atomic Test Case –
ATC)
• Expert review of the PMI
• Applied to 5 parts (Fully-Toleranced Test Case – FTC)
• Test Models
• Each of the 5 parts with PMI modeled in 4 CAD systems
(more recent versions of CATIA, Creo, NX, SolidWorks)
• Focus on Semantic PMI
• Verification of CAD models
• Comparison to test case definitions and to each other
• Implementor Forums (IFs) to resolve modeling issues
• Release to IFs
• Generate derivative STEP, JT, and 3D PDF files
• Validate derivative files to original CAD models
• Import derivation STEP files to CAD systems
• Validate derivative CAD models to original CAD models
Summary
• Semantic PMI is a fundamental component of
the Digital Thread
• Semantic PMI implementation is a challenge
• NIST has a growing collection of digital test
artifacts and tools for verification and
validation of CAD implementations of
semantic PMI

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