1
Quiz Preparation
Have Quiz sheet ready.
 Top Center: QUIZ 2
 Upper Right:
» Name (L, F, MI),
» Today’s date 8/28/12
» Lab day , time
» section number

Lab Day/Time
Mon.
Mon.
Tue.
Wed.
Wed.
Wed.
Thu.
Thu.
Fri.
Fri.
1:00
3:00
2:00
1:00
1:00
3:00
3:00
2:00
2:00
1:00
1:00
Section
Number
8
9
36
10
10
11
11
29
35
12
12
2
Announcements

Each team must purchase the following
before Lab 5:
» 2 Lego Power Functions 8883 M-Motors
» Approx. $10 each

Waiting to hear about availability from the
Scientific Supply Store on campus.
3
Quiz

1. What does your team need for Lab 5
(select only one answer) ?
» a. Two LEGO motors
» b. Keypad code
» c. bucket of LEGOs
» 2. Motors are provided for you at no cost (True
or False).
4
Design Project
5
Competition

Each team designs and builds a car
» Specifications in syllabus
» Work on car done outside of class
» Team must build the car with their own supplies
– No supplies are provided

Lectures/Labs 1-7 provide background material for
the design project

Start early on the design project!

COMPETITION –Thursday, 11/8, at 7 PM in BR
125.
6
Optional Gates
(+5 sec. penalty if missed)
Push block across finish
line or incur a +30 sec.
penalty
START/
FINISH
BLOCK
Required Gates
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
8
Quiz

3. In this class, our design process stops
after
» a. Prototyping (making one)
» b. Production (making many)
9
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
10
Engineering Design Process

Example: Zero-Emission Vehicle

Identify customer needs.
» “I want a vehicle that is affordable.”
» “I want a vehicle I can use to drive to and from
work every day.”
» “I want a vehicle that does not pollute the
environment.”
» “I want a vehicle that is safe to operate.
11
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
12
Engr. Design Process (cont’d)

Establish product specification.
» Performance should be comparable to a
conventional automobile.
» Initial purchase cost should be $30,000.
» Consumables must be recyclable or not release
toxins to the environment upon disposal or an
accident
13
Quiz

4. Which one establishes a contract between
the customer and the supplier?
» a. Customer needs
» b. Specifications
14
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
15
Brainstorming





The brain uses two basic modes in the design
process:
» creative mode
» critical mode
These two modes work against each other.
Some people are better at one mode than the other
Brainstorming separates the two processes into
different time frames.
It is important not to think critically during
brainstorming.
16
Engr. Design Process (cont’d)

Define alternative strategies
»
»
»
»
Lithium-ion battery
Lead-acid battery
Compressed Air
Etc.
17
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
18
Engr. Design Process (cont’d)

Select the most
suitable concept.
» Cost
» Environmental risks
» Reliability
» Ease of use
– Design cost
– Material cost
– Assembly cost
»
»
»
»
Weight
Appearance
Performance
Safety
19
Tradeoffs in Engineering Design
Examples:
 Cost vs. performance
 Safety vs. performance
 Performance vs. reliability
20
Selecting the Most Suitable Concept

Typically, you have
» Several design alternatives
» Multiple, often conflicting, criteria

How do you sort all this out?
21
Pugh Chart
BEST
22
Design Reports

A Pugh chart will be REQUIRED for each
design decision in your preliminary and
final design reports.
23
Pugh Chart Advantages

Gives structure to the decision-making
process

Documents the decision-making process
24
Alternative Methods
Positives and Negatives (Pros vs Cons)
 Analytical Hierarchy Process
 House of Quality Method

25
House of Quality
26
Quiz

5. Brainstorming is the process of critiquing
various alternatives to select the best one.
Write TRUE or FALSE
27
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
28
Engr. Design Process (cont’d)

Design the subsystems and integrate them
» Break a complex system into small subsystems
Zero-Emission Car
Body
Motor/
Trans.
Power
Mgmt
Electrical
29
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
30
Engr. Design Process (cont’d)

Build and test a prototype
» Build and test each subsystem
» Integrate and test the subsystems
Zero-Emission Car
Body
Motor/
Trans.
Power
Mgmt
Electrical
31
Engineering Design Process
Identify Customer Needs
Establish Product Specification
Define Alternative Concepts
Select the Most Suitable Concept
Design/Integrate Subsystems
Build/Test Prototype
Design/Build Production
Produce
Track
32
Design for Lego Car
Specification is given.
 Define alternative concepts.
 Select the most suitable concept.

» Bottom line is finishing time.
» “Cost” is figured in by penalizing use of parts.
» Car should be sturdy enough not to fly apart
during race.
» Car and course must pass minimal safety specs.
33
Design Subsystems
Car path & steering strategy
 Power supplied to vehicle
 Torque vs speed
 Vehicle mass, wheels, etc.

34
Lego Car Subsystems

Output voltage
» Higher output voltage increases speed
» Penalties apply above 10V

Power supply (batteries)
» One 9V battery (light, but less than 10V)
» Two 9V batteries (≥10V, but heavy)
» Watch batteries (very light, but drain quickly)

Wheel size and gears
» Torque vs. speed tradeoff

Drive strategy
» Front wheel vs. rear wheel drive

Course path
» Passing through all gates vs. missing gates
» Pushing block vs. not pushing block

Body
» Light vs. heavy
35
Further Design Steps
Build and test, then modify!!!
 Production design, distribution, and tracking
are not relevant to a single-shot prototype
design.

36