Electrical Circuits I

1
Agenda for Monday July 16, 2007 0900 Welcome for
the Day (BC/NG/HD and faculty) AIM for Stars
overview (Neal) Lesson Idea List distribution
(Neal) 0915 Bill and Jims Lesson Samples and
Examples (Bill, Jim) 0945 Engineering Design
Tools (HD) Objectives and Constraints Scheduli
ng Technical Writing 1015 Breakout
(Observations/Questions) (HD?) Is engineering
for everyone in the 21st century? Who would be
good at engineering? 1045 Break 1115 What
teachers should know about the TekBot
(HD) Sensors, Light, Force Sensors, Sound,
Position 1200 Lunch 1300 Hands-On Assembly and
Test of Analog Brain Board 1530 Adjourn (adjourn
directly from labs)
2
Silicon Prairie Initiative on Robotics in
Information Technology

• Engineering Design Tools

3
Heuristics

• A heuristic is anything that provides a plausible
  aid or direction in the solution of a problem.
• Heuristics are usually unjustified and
  potentially fallible.
• Engineering design is the use of heuristics.
• Heuristics are used to cause the best change in a
  poorly understood situation within the available
  resources.

4
Sample Engineering Heuristics

• Rules of Thumb and Orders of Magnitude
• Attitude-Determining Heuristics
• Risk-Controlling Heuristics
• Resource Allocation Heuristics
• Miscellaneous Heuristics

5
Rules of Thumb

• Ambient temperature 20? C
• Air 80 nitrogen, 20 oxygen
• Forward biased diode voltage 0.7 V
• LED 1.5V
• One gram of uranium gives one mega-watt day of
  energy
• Building construction scales as the price of meat
• Screws have a point, bolts are flat

6
Attitude-Determining Heuristics

• Quantify or express all variables in numbers
• Always give an answer
• Work at the margin of solvable problems

7
Risk-Controlling Heuristics

• Make small changes from previous successful
  solutions.
• Always give yourself a chance to retreat.
• Use feedback to stabilize a design

8
Resource Allocation Heuristics

• Allocate sufficient resources to the weak link.
• Allocate resources as long as the cost of not
  knowing exceeds the cost of finding out.
• At some point in the project, freeze the design.

9
Miscellaneous

• Break complex problems into smaller, more
  manageable pieces.
• Design for a specific time frame.
• Always make the minimum decision.

10
Problem Definition 1. Clarify objectives 2.
Establish user requirements 3. Identify
constraints 4. Establish functions
Client Statement (Need)
Conceptual Design 5. Establish design
specifications 6. Generate alternatives
Design Process
Preliminary Design 7. Model or analyze design 8.
Test and evaluate design
Detailed Design 9. Refine and optimize design
Final Design (Fabrication Specs Documentation)
Design Communication 10. Document design
11
Convergent (left brain) and Divergent (right
brain) Thinking
12
Problem Definition

• Methods
• Objective Tree
• Pairwise Comparison Chart
• Weighted Objectives Tree
• Function-Means Tree
• Functional Analysis
• Requirements Matrix

• Means
• Literature Review
• Brainstorming
• User Surveys and Questionnaires
• Structured Interviews

13
Building an Objectives Tree
14
Building an Objectives Tree
15
Functional Analysis

• What does the design DO?
• What functions must be performed to realize the
  objectives?
• Put the language of the client and users into the
  language of the engineer.
• Put things into terminology that helps to find
  ways to meet objectives.
• Use terminology that can be used to measure how
  well the objectives have been met.

16
What are Functions?

• A relationship between independent variables
  (inputs) and response or dependent variables.
  (outputs)
• Mathematics
• Business Management Theory

Transformation function
17
Black and Glass Boxes

• Like the mathematical and management models -
  relate the inputs to the outputs
• All ins and outs must be specified
• What happens to each input?
• Where does the output come from?
• Remove the cover to see what's going on inside.

Black Box
18
Black Box of a Radio
19
Radio Glass Box(the cover has been removed)
20
Function-Means Tree

• A graphical representation of the design's basic
  and secondary functions
• Alternating levels of function and means
• Begins the process of association of what must be
  done and how we might do it.
• Can be used to separate and sort secondary
  functions associated with the design.

21
(No Transcript)
22
Heuristics

• A heuristic is anything that provides a plausible
  aid or direction in the solution of a problem.
• Heuristics are usually unjustified and
  potentially fallible.
• Engineering design is the use of heuristics.
• Heuristics are used to cause the best change in a
  poorly understood situation within the available
  resources.

23
Conceptual Design Finding a Feasible Concept.

• Break down the overall problem into subproblems.
• Find solutions to each subproblem
• Combine the subproblem solutions.
• The aim is to start with the project definition
  and generate as many ways as possible of solving
  the problem.
• Then select the most promising ideas that meet
  the design specification.

24
Conceptual Design

• Methods
• Performance Specification Method
• Quality Function Deployment (QFD)
• Morphological Chart

• Means
• Brainstorming
• Synectics and Analogies
• Benchmarking
• Reverse Engineering (Dissection)

25
Convergent (left brain) and Divergent (right
brain) Thinking