Welcome to the Fourth Step of the Engineering Design Cycle: Finding the Best Solution among Many!

1. The Engineering
Design Cycle
Part 4:
Select the Best
Solution
http://labs.ee.washington.edu/community/BasicEngDes/BasicEngDes_SelectSolution/

2. A problem has been identified.
The problem has been
researched. The need to solve it
has been proven with credible
sources. A range of solutions
have been identified. Now, it's
decision time!
Selecting the best solution
should not be a random or even
a semi-random choice, but
should rely on a careful and
objective decision making
process that in addition to
helping to select the best
solution, can also be used to
offset failure, if it does happen!
The Engineering Design Cycle
Identify the
Problem
Construct
Prototype
Research the
Need
Select the
Best Solution
Design
Solutions
Redesign/
Iterate
Test and
Evaluate
Present the
Solution

3. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Consider each solution for an accelerometer application:
Does each design provide the required performance metrics?

4. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Consider each solution for an accelerometer application:
Does each design provide the required performance metrics?
Some designs may require
preliminary models, hand
calculations, or simulations to
understand if the design is likely
to meet the design specifications.
If it is not clear whether or not
the solution can meet the design
specification, the team will have
to decide if the solution is worth
the risk to pursue it.

5. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Any design that does not meet one
or more design specifications (in
the case above, performance
metrics) must be automatically
rejected OR in some situations, it
may be necessary to go back to the
• Research the Need or
• Design Solutions
phase of the engineering design
cycle to understand if the
specifications are too stringent and
can be relaxed.
Consider each solution for an accelerometer application:
Does each design provide the required performance metrics?

6. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Consider each solution for an accelerometer application:
Does each design remain within the specified constraints?

7. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Consider each solution for an accelerometer application:
Does each design remain within the specified constraints?
Like performance metrics, some
constraints may be impossible or
difficult to estimate for some
design solutions. These solutions
may require:
• Returning to previous phases of
the design cycle to see if the
constraint can be relaxed.
• Identifying how much risk the
design team is willing to take
(and the consequences for
failure).

8. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Which Solutions pass the first pass (Decision Matrix)?

9. Decision Making with a Decision Matrix
Select the
Best Solution
during
the
Engineering
Design
Cycle
Which Solutions pass the first pass (Decision Matrix)?
Solution #6 is the only clear winning solution here, but Solution #4
might also be viable. Which one should be selected to move
forward into the prototyping phase?

10. The Engineering Design Cycle
When the Basic Decision Matrix is not Enough:
A more sophisticated planning method can be used to
evaluate which design provides the best pathway toward a
solution to the problem.
One such method, called SWOT (Strengths, Weaknesses,
Opportunities, Threats), is a popular planning method which
allows the project team to identify both internal factors in the
design and design team (through strengths and weaknesses)
and external factors that may also influence the design and
design team (through opportunities and threats).

11. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Strengths - are the characteristics of the design or the design team
that give a possible design solution an advantage over other
competing options.

12. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Strengths - are the characteristics of the design or the design team
that give a possible design solution an advantage over other
competing options.
Examples of
Strengths:
• Design is
conducive to
fast and
inexpensive
prototyping.
• Design team
member has
previous
expertise in a
key area
associated
with a
particular
design.

13. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Weaknesses - are areas that will be highlighted in the selection of
particular design or characteristics of the design team that will
need to be improved to make the design successful.

14. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Weaknesses - are areas that will be highlighted in the selection of
particular design or characteristics of the design team that will
need to be improved to make the design successful.
Examples of
Weaknesses:
• Design requires
extensive
interviewing to
identify market
and the team is
not particularly
outgoing
• Design relies on
a part that has
limited
availability and
long lead time.

15. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Opportunities - are external elements (things out in the real
world) that can be used or exploited to the advantage of the
design or design team.

16. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Opportunities - are external elements (things out in the real
world) that can be used or exploited to the advantage of the
design or design team.
Examples of
Opportunities:
• Certain consumers are
so desperate for a
product with a
particular function
that they are likely to
tolerate non-idealities.
• A new federal
requirement,
regulation, or law is
scheduled to take
effect, stimulating a
need for products in a
particular design area.

17. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Threats - are things out there in the real world that could cause
trouble for the design.

18. Decision Making with SWOT
Select the
Best Solution
during
the
Engineering
Design
Cycle
Threats - are things out there in the real world that could cause
trouble for the design.
Examples of Threats:
• A competing product is
coming onto the market
or has been proven and
published via research
publication, patent, or
similar release.
• The application for the
design could change
drastically because of
shifting consumer
desires or alternative
technologies emerging
into the market.
• A social issue or
constraint has the
potential to submarine
the design altogether.

19. The Engineering Design Cycle
Caution - Is the Decision Biased or Subjective?
Even engineers are human and during the selection of a
design solution, engineers can show bias in preferring
certain choices over others, despite the fact that objectively,
these choices are not better than others.
Solution - Become a more objective Decision Maker
• Become aware of bias
• Know the types of bias each team member is most
susceptible to
• Take steps to prevent bias from causing the design team
to select non-optimal design choices.

20. Objective Decision Making
Select the
Best Solution
during
the
Engineering
Design
Cycle
Acknowledge your Biases in Design and in Decision Making!

21. Objective Decision Making
Select the
Best Solution
during
the
Engineering
Design
Cycle
Acknowledge your Biases in Design and in Decision Making!
• Do you resist stepping backward in the design process, even
when it may be the best thing to do to avoid failure?
• Do you tend to pick the easiest solution?
• Do you pursue the most challenging solution?
• Do you (almost always) prefer incremental solutions?
• Do you automatically oppose the opinion/choices of certain
others on your team?
• Are you prone to jumping ahead into the build and test phase
of design because thinking about it is boring?
• Other biases?

22. Objective Decision Making
Select the
Best Solution
during
the
Engineering
Design
Cycle
Compensate for your Biases
Imagine counseling a friend on the design choice
Ask an outsider to evaluate your design choice
• Those as or more knowledgeable than you
• Those who know nothing about the design

23. Objective Decision Making
Select the
Best Solution
during
the
Engineering
Design
Cycle
Compensate for your Biases
Strip the choice down to a smaller number of decision factors

24. Objective Decision Making
Select the
Best Solution
during
the
Engineering
Design
Cycle
Compensate for your Biases
Use Reverse Line Thinking
• What's the worst
that can happen
with one design
choice over another?
• How will the worst
consequences
change your future
and livelihood?

25. Select the Best Solution
Select the Best Solution
using
1. Decision Matrices
1. Design Specifications
(Metrics)
2. Design Specifications
(Constraints)
2. SWOT Analysis
3. Other planning methods, as
needed
4. Objective Decision Making
Identify the
Problem
Construct
Prototype
Research the
Need
Select the
Best Solution
Design
Solutions
Redesign/
Iterate
Test and
Evaluate
Present the
Solution

26. Making a Block Diagram
for the Selected Solution
• Show every major component or stage in the design.
• Clearly identify inputs to the system (where inputs are
those signals obtained from outside the system).
• Clearly label outputs from the system (where outputs
are generated from within the system & provided to the
user of that system).
Guidelines

27. Making a Block Diagram
for the Selected Solution
• Places inputs and outputs at the beginning and end of
the signal flow.
• Indicates major decisions and branches in the signal
flow.
• Uses arrows to indicate proper direction of signal flow
from one stage or component to the next.
Guidelines

28. Making a Block Diagram
for the Selected Solution
• Place inputs and outputs at the beginning and end of the
signal flow.
• Indicate major decisions and branches in the signal flow.
• Use arrows to indicate proper direction of signal flow
from one stage or component to the next.
Guidelines

29. Making a Block Diagram
for the Selected Solution
• Minimize the use of text and maximizes the use of visual
presentation to ensure that the scope and structure of
the design are readily communicated to the reader.
• Allow space for key performance metrics and constraints
(e.g. the design specification).
Guidelines

30. Block Diagram –
an Example
Appear Complete?
Show Inputs?
Show Outputs?
Show Signal Flow?
Does this Block Diagram...

31. Block Diagram –
an Example (cont.)
Does this Block Diagram have...
Structure?
Visualization?
Minimized Text?
Communication?

32. Block Diagram –
another Example
Does this Block Diagram...
Appear Complete?
Show Inputs?
Show Outputs?
Show Signal Flow?

33. Block Diagram –
another Example (cont)
Does this
Block Diagram have...
Structure?
Visualization?
Minimized Text?
Communication?

34. Block Diagram –
another Example
Does this
Block Diagram:
Appear Complete?
Show Inputs?
Show Outputs?
Show Signal Flow?

35. Block Diagram –
another Example (cont)
Does this
Block Diagram have:
Structure?
Visualization?
Minimized Text?
Communication?

36. Block Diagram –
another Example
Does this Block Diagram:
Appear Complete?
Show Inputs?
Show Outputs?
Show Signal Flow?

37. Block Diagram –
another Example (cont)
Does this Block Diagram have:
Structure?
Visualization?
Minimized Text?
Communication?

38. Block Diagram –
another Example
Does this Block Diagram...
Appear Complete? Show Inputs? Show Outputs? Show Signal Flow?

39. Block Diagram –
another Example (cont)
Does this Block Diagram have...
Structure? Visualization? Minimized Text? Communication?

40. Select the Best Solution
The Block Diagram
• A good engineering block
diagram clearly communicates
where a design begins and
ends in terms that any reader
can understand.
• The block diagram should
communicate visually the basic
structure and flow of a design in
a way that the reader can
clearly understand the purpose
and function of the overall
design.
• A good block diagram allows
the reader to refer back to it
when reading more in detail
about different components of
that design.
Identify the
Problem
Construct
Prototype
Research the
Need
Select the
Best Solution
Design
Solutions
Redesign/
Iterate
Test and
Evaluate
Present the
Solution

41. Thanks for joining us as we explored the fourth step of the
Engineering Design Cycle: Select the Best Solution.
Complete Educational Materials (including assignments,
quizzes, and recorded lectures) on the topic of Basic
Engineering Design can be found at:
http://labs.ee.washington.edu/community/BasicEngDes/
The Engineering Design Cycle