The Process of Design

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Chapter 2

• The Process of Design

2
Design Process

• The 12-Step Design Process is

• Define the Problem
• Brainstorming
• Researching and Generating Ideas
• Identifying Criteria and Specifying Constraints
• Exploring Possibilities
• Selecting an Approach
• Developing a Design Proposal
• Making a Model or Prototype
• Testing and Evaluating
• Refining
• Creating or Making
• Communicating Process and Results

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Define the Problem

• At this phase of the project, the problem is
  identified and defined.
• Discussion of problem
• Disposal and rechargeable batteries have been
  used to power everything from cellular phones to
  computers. The Hubble space telescope depends on
  batteries to power its electronics during night
  orbits.
• Because the space craft has been in service for
  18 years, the batteries have come to the end of
  their service life.
• Example of solution A new battery design that
  will replace existing batteries and thus extend
  the life of the spacecraft as well as provide
  more power for future instrument packages.

http//www.nasa.gov/mission_pages/hubble/servicing
/series/battery_story.html
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Brainstorming

• Each team member contributes his or her unique
  ideas in order to generate solutions to the
  problem.

Nickel-cadmium batteries
Lithium ion polymer batteries
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Researching and Generating Ideas

• Used to discover prior implemented solutions to
  particular design problems.

Currently, the Hubble space telescope is using
nickel-hydrogen batteries.
Courtesy of JupiterImages/Plainpicture
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Identifying Criteria and Specifying Constraints

• Detail what you intend to do and the imposed
  limitations.

• The battery must
• Not exceed 460 lbs
• 36" x 32" x 11"
• Min. of 75 amp-hours
• Deliver 24 volts

Courtesy of JupiterImages/Liquidlibrary.
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Exploring Possibilities
Exploring all possible solutions. (This phase
requires attention to detail.)

• Lithium ion polymer batteries varies from 2.7
  volts (discharged) to 4.23 volts (fully charged).
• Have to be protected from overcharge by limiting
  the applied voltage to no more than 4.235 volts
  per cell used in a series combination.

Courtesy Jim B. MacDonald
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Selecting an Approach
Courtesy of JupiterImages/Workbook Stock

• Perform an assessment and then choose a design
  path.

I dont really think this is the right way to
make an assessment.
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Developing a Design Proposal
http//www.nasa.gov/mission_pages/hubble/servicing
/SM4/main/index.html
Create a clear documented description of the
design.
Background During Hubbles sunlight (or day)
orbit, the solar array panels provide power to
the electrical components and charge the
batteries. This supplies enough power to support
Hubble during its night orbit.
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Making a Model or Prototype
http//www.nasa.gov/mission_pages/hubble/servicing
/series/battery_story.html
With the design proposal completed, a model or
prototype of the solution is constructed.
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Testing and Evaluating

• The model or prototype is tested to determine how
  well the design meets the criteria set earlier in
  the project.

Courtesy of Aiolos, www.aiolos.com
12
Refining
Any problems and/or concerns indicated in the
testing phase are addressed in the refining phase.
Courtesy of Workbook Stock/JupiterImages
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Creating or Making
At this point in the process, the design is sent
to production.
Courtesy of Z Corporation
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Communicating Process and Results
At this point in the process, the final
documentation is prepared.