Set-Based Prototyping

Ashwin MichaelrajGraduate Research Assistant

Mechanical Engineering DepartmentClemson University

amichae@clemson.edu

Dr. Joshua D. SummersAssistant Professor

Mechanical Engineering DepartmentClemson University

joshua.summers@ces.clemson.edu

24 March 2008

2/122008.03.24

Set-Based Prototyping Outline Prototype

– Definition– Conventional Prototyping practice– Advantages & Limitations

Introduction to Set-Based Prototyping– Working principle / ‘Set-Based’ principle– Need for ‘Set-Based Prototyping’– Intended use

Requirements for a SBP Tool– Identifying factors and characteristics that influence prototype selection– Prototype design space– SBP tool architecture

Experiments to validate SBP Tool– Student project trials– Web trials

Thesis time line– Work completed– Future work

http://aid.ces.clemson.eduamichae@clemson.edu

3/122008.03.24

Set-Based Prototyping Prototype

Definition– A prototype is a physical instantiation of a product, meant to be used

to help resolve one or more issues during the product development [1, 2]

– Other definitions include Test-beds which enable designers to test their design [3] An artifact or model (physical or virtual) which acts as a catalyst for

further development and evolution [1]

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Physical Prototype Virtual Prototype

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Set-Based Prototyping Conventional Prototyping Practice

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REQUIREMENTS

CONCEPT GENERATION

PROTOTYPING (LOW

FIDELITY)

DESIGN EVALUATION/R

EVIEW

PROTOTYPING (HIGH

FIDELITY)TESTING

PRODUCT TRIAL

CONSUMER EVALUATION

PRODUCT RELEASE

• Three major reasons for multiple prototyping iterations in the design process - Customer dissatisfaction with the design - Poor product performance during internal testing & external testing - Poor selection of initial prototype/design [4]• Conventional prototyping practice follows a point-based approach during

product development – which is selection of initial prototype and modifications to it.

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Set-Based Prototyping Advantages & Limitations Advantages

– Physical prototypes help detect unanticipated phenomena– Reduces the chances of failure of a product– May expedite other product development processes

Limitations– General

Physical prototypes are time consuming* when compared to virtual/analytical prototype

Flexibility offered by virtual/analytical prototypes in modifying design parameters is higher than the physical prototypes

– Selection (Currently prototypes & prototyping techniques are selected based on intuition or experiential knowledge)

When to prototype during a design process? Which prototype suits designer’s needs?

* (depends on complexity of design)

http://aid.ces.clemson.eduamichae@clemson.edu

6/122008.03.24

Set-Based Prototyping Introduction to Set-based Prototyping ‘Set-based’ principle

– Invented by Toyota Motor Corporation as a part of lean product design technique known as Set-Based Concurrent Engineering (SBCE)

– Begins by considering ‘sets of possible solutions’ and then narrowing down the solutions by eliminating the weaker solutions [5]

– Deductive approach (Set-based) rather than Inductive approach (Point-based)

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DESIGN SPACE

DESIGN A

DESIGN B

DESIGN C

OPTIMAL SOLUTION

ELIMINATE WEAK SOLUTIONS

OPTIMAL SOLUTION

SET-BASED APPROACH

DESIGN SPACE SINGLE DESIGN MODIFICATIONS

POINT-BASED APPROACH

OPTIMAL SOLUTION

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Set-Based Prototyping Need for set-based prototyping Set-based prototyping approach offers following advantages over traditional

point-based prototyping approach– Rate of convergence of a final solution is higher– Reduces the probability of starting all over again– Eliminates the need for multiple iteration of a prototype– Quality of solution obtained is higher– Though populating sets of solution from design space seems time

consuming, in general it leads to reduction in overall product development cycle [5]

Intended use of set-based principle– Selection of prototypes during product development (which is currently

based on intuition/experiential knowledge)– Develop a design tool which helps even a novice designer with a structured

approach to prototype selection

http://aid.ces.clemson.eduamichae@clemson.edu

8/122008.03.24

Set-Based Prototyping Requirements of a SBP Tool Identifying factors and characteristics that influence prototype selection

– Communication– Evaluation purpose– Cost– Design stage– Size– Type (Novel, Variant)– Material– Fabrication

Prototype design space– Classifying and naming prototypes based on these factors and characteristics

(Taxonomy) Querying system to extract information about the desired prototype from designer

– Based on Mixed initiative/Conversational reasoning techniques Confidence rating system

– A statistical ranking system to identify which prototype serves the intended purpose(s) better

– Say Prototype A – 75% Confidence level, Prototype B – 90% Confidence level etc

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9/122008.03.24

Set-Based Prototyping SBP tool architecture

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MIXED INITIATIVE/ CONVERSATIONAL

REASONING

PROTOTYPE DESIGN SPACEPROTOTYPE

DESIGN SPACEQUESTIONNAIRES

DATABASE

QUERYING MODULE

PROTOTYPERPROTOTYPE STATISTICAL DATA

STATISTICAL CONFIDENCE

MEASUREMENT

RATING MODULE

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Set-Based Prototyping Experiments to validate SBP Tool Student project trials

– ME 402 – Design projects – Fall 08 Web Trial

– Based on the feed back from student projects an online version of the tool will be made available to designers and academia

Thesis time line

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TaxonomyNaming Prototypes

based on factors and characteristics

SBP Tool Student and Web Trials Thesis Writing Thesis Defense

Jan 08 Apr 08 July 08 Aug 08 Oct 08 Dec 08

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Set-Based Prototyping References

1. Otto K. N., and Wood K. L., 2001, Product design: Techniques in reverse engineering and new product development, Prentice-Hall, Inc. New Jersey, USA.

2. Ulrich K. T., and Eppinger S. D., 2000, Product design and development, McGraw-Hill, Inc, USA.

3. Wall M. B., Ulrich K. T., and Flowers W. C., 1992, “Evaluating Prototyping Technologies for product design”, Journal of Research in Engineering Design 3(3), Springer International, New York, USA, pp. 163-177.

4. Bhushan N., 2007, “Set-based concurrent engineering (SBCE) and TRIZ – A framework for global product development”, Wipro Technologies, India.

5. Sobek D. K., Ward A. C., and Liker J. K., 1999, “Toyota’s principle of set-based concurrent engineering”, Sloan Management Review 40.2.

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12/122008.03.24

Set-Based Prototyping

http://aid.ces.clemson.eduamichae@clemson.edu

QUESTIONS ???