Quiz Preparation

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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 Section Number

Mon. 1:00 8Mon. 3:00 9Wed. 1:00 10Wed. 3:00 11Thu. 2:00 29Fri. 1:00 12

Lab Day/Time Section Number

Mon. 1:00 8Mon. 3:00 9Tue. 2:00 36Wed. 1:00 10Wed. 3:00 11Thu. 2:00 35Fri. 1:00 12

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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.

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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).

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Design Project

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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.

START/FINISH

BLOCK

Required Gates

Optional Gates(+5 sec. penalty if missed)

Push block across finish line or incur a +30 sec. penalty

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Identify Customer NeedsEstablish Product Specification

Define Alternative ConceptsSelect the Most Suitable Concept

Design/Integrate SubsystemsBuild/Test Prototype

Design/Build ProductionProduceTrack

Engineering Design Process

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Quiz

3. In this class, our design process stops after» a. Prototyping (making one)» b. Production (making many)

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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.

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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

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Quiz

4. Which one establishes a contract between the customer and the supplier?» a. Customer needs» b. Specifications

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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.

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Engr. Design Process (cont’d)

Define alternative strategies» Lithium-ion battery» Lead-acid battery» Compressed Air» Etc.

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Select the most suitable concept.» Cost

– Design cost– Material cost– Assembly cost

» Weight» Appearance» Performance» Safety

» Environmental risks» Reliability» Ease of use

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Tradeoffs in Engineering Design

Examples: Cost vs. performance Safety vs. performance Performance vs. reliability

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Selecting the Most Suitable Concept

Typically, you have» Several design alternatives» Multiple, often conflicting, criteria

How do you sort all this out?

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Pugh Chart

BEST

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Design Reports

A Pugh chart will be REQUIRED for each design decision in your preliminary and final design reports.

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Pugh Chart Advantages

Gives structure to the decision-making process

Documents the decision-making process

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Alternative Methods

Positives and Negatives (Pros vs Cons) Analytical Hierarchy Process House of Quality Method

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House of Quality

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Quiz

5. Brainstorming is the process of critiquing various alternatives to select the best one.

Write TRUE or FALSE

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Design the subsystems and integrate them» Break a complex system into small subsystems

Body Motor/Trans.

Power Mgmt Electrical

Zero-Emission Car

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Build and test a prototype» Build and test each subsystem» Integrate and test the subsystems

Body Motor/Trans.

Power Mgmt Electrical

Zero-Emission Car

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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.

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Design Subsystems

Car path & steering strategy Power supplied to vehicle Torque vs speed Vehicle mass, wheels, etc.

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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

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Further Design Steps

Build and test, then modify!!! Production design, distribution, and

tracking are not relevant to a single-shot prototype design.