Engineering Laboratory Systems Integration Division

Transcription

1 PMI Validation and Conformance Testing for Model-based Engineering Joshua Lubell Systems Engineering Conference in Washington DC (SEDC) April 3, Engineering Laboratory Systems Integration Division

2 Outline 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.

3 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

4 PMI Example from a Standard * * ISO 1101, Geometrical product specifications (GPS) geometrical tolerancing tolerances of form. Orientation, location and run-out (2nd ed.) International Organization for Standardization, Geneva (Switzerland) (2004)

5 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

6 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

7 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 Y Dimensioning and Tolerancing ASME Y Digital Product Data Definition Practices

8 Test Cases Project Components (1) 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

9 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

10 MBE PMI Validation Data Process Flow Expert Review CATIA V5 Models CAx-IF STEP Files CATIA V5 Models Test Cases Creo Models NX Models JT-IF JT Models Creo Models NX Models SolidWorks Models 3D PDF-IF 3D PDF Models SolidWorks Models Verification Implementer Forum = Vendor partnership to identify & resolve implementation issues Validation

11 Test Cases versus Test Models * Test Case a PMI construct Test Model its CAD implementation * Figures from NIST MBE PMI Validation Project Update, ITI Transcendata, February 2013

12 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

13 Sample PMI Annotation Constructs

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19 Complex Test Cases Spreadsheet

20 Atomic Test Cases Spreadsheet

21 Test Case Browser Demo

22 Test Cases Modeled in 4 CAD Systems Test Case CATIA V5 R21 Model NX 8.0 Model SolidWorks 2012 Model Creo 2.0 Model

23 Example Semantic Verification Issue in-between designation and bounds (edges) are non-semantic.

24 Results Test Cases 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)

25 NIST STEP File Analyzer and Semantic PMI STEP File Analyzer parses ISO 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

26 Semantic PMI Summary Worksheet Recreate Visual Presentation of the Semantic PMI Datum systems, dimensional and geometric tolerances

27 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

28 Phase 2 Plans Test Cases 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

29 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