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2 Quiz Preparation l Have Quiz sheet ready. l Top Center: QUIZ 2 l Upper Right: »Name (L, F, MI), »Today’s date 8/28/12 »Lab day, time »section number Lab Day/TimeSection Number Mon. 1:008 Mon. 3:009 Wed. 1:0010 Wed. 3:0011 Thu. 2:0029 Fri. 1:0012 Lab Day/TimeSection Number Mon. 1:008 Mon. 3:009 Tue. 2:0036 Wed. 1:0010 Wed. 3:0011 Thu. 2:0035 Fri. 1:0012

3 Announcements l Each team must purchase the following before Lab 5: »2 Lego Power Functions 8883 M-Motors »Approx. $10 each l Waiting to hear about availability from the Scientific Supply Store on campus.

4 Quiz l 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).

5 Design Project

6 Competition l 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 l Lectures/Labs 1-7 provide background material for the design project l Start early on the design project! l 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

8 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 Engineering Design Process

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

10 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

11 Engineering Design Process l Example: Zero-Emission Vehicle l 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.

12 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

13 Engr. Design Process (cont’d) l 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

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

15 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

16 Brainstorming l The brain uses two basic modes in the design process: »creative mode »critical mode l These two modes work against each other. l Some people are better at one mode than the other l Brainstorming separates the two processes into different time frames. l It is important not to think critically during brainstorming.

17 Engr. Design Process (cont’d) l Define alternative strategies »Lithium-ion battery »Lead-acid battery »Compressed Air »Etc.

18 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

19 Engr. Design Process (cont’d) l Select the most suitable concept. »Cost –Design cost –Material cost –Assembly cost »Weight »Appearance »Performance »Safety »Environmental risks »Reliability »Ease of use

20 Tradeoffs in Engineering Design Examples: l Cost vs. performance l Safety vs. performance l Performance vs. reliability

21 Selecting the Most Suitable Concept l Typically, you have »Several design alternatives »Multiple, often conflicting, criteria l How do you sort all this out?

22 Pugh Chart BEST

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

24 Pugh Chart Advantages l Gives structure to the decision-making process l Documents the decision-making process

25 Alternative Methods l Positives and Negatives (Pros vs Cons) l Analytical Hierarchy Process l House of Quality Method

26 House of Quality

27 Quiz l 5. Brainstorming is the process of critiquing various alternatives to select the best one. Write TRUE or FALSE

28 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

29 Engr. Design Process (cont’d) l Design the subsystems and integrate them »Break a complex system into small subsystems Body Motor/ Trans. Power Mgmt Electrical Zero-Emission Car

30 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

31 Engr. Design Process (cont’d) l Build and test a prototype »Build and test each subsystem »Integrate and test the subsystems Body Motor/ Trans. Power Mgmt Electrical Zero-Emission Car

32 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

33 Design for Lego  Car l Specification is given. l Define alternative concepts. l 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.

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

35 Lego Car Subsystems l Output voltage »Higher output voltage increases speed »Penalties apply above 10V l Power supply (batteries) »One 9V battery (light, but less than 10V) »Two 9V batteries (≥10V, but heavy) »Watch batteries (very light, but drain quickly) l Wheel size and gears »Torque vs. speed tradeoff l Drive strategy »Front wheel vs. rear wheel drive l Course path »Passing through all gates vs. missing gates »Pushing block vs. not pushing block l Body »Light vs. heavy

36 Further Design Steps l Build and test, then modify!!! l Production design, distribution, and tracking are not relevant to a single-shot prototype design.