Transcript Electrical Circuits I

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 Jim’s Lesson Samples and Examples (Bill, Jim)
0945
Engineering Design Tools (HD)
Objectives and Constraints
Scheduling
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)
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SPIRIT
Silicon Prairie Initiative on Robotics in
Information Technology
Engineering
Design Tools
2
SPIRIT
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.
3
SPIRIT
Sample Engineering Heuristics
Rules
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of Thumb and Orders
of Magnitude
Attitude-Determining
Heuristics
Risk-Controlling Heuristics
Resource Allocation
Heuristics
Miscellaneous Heuristics
SPIRIT
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
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SPIRIT
Attitude-Determining
Heuristics
Quantify
or express all
variables in numbers
Always give an answer
Work at the margin of
solvable problems
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SPIRIT
Risk-Controlling Heuristics
Make
small changes from
previous successful
solutions.
Always give yourself a
chance to retreat.
Use feedback to stabilize a
design
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SPIRIT
Resource Allocation
Heuristics
Allocate
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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.
SPIRIT
Miscellaneous
Break
complex problems into
smaller, more manageable
pieces.
Design for a specific time
frame.
Always make the minimum
decision.
9
SPIRIT
Client Statement
(Need)
Problem Definition
1. Clarify objectives
2. Establish user requirements
3. Identify constraints
4. Establish functions
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
10
SPIRIT
Convergent (left brain) and
Divergent (right brain) Thinking
11
SPIRIT
Problem Definition
 Methods
 Means
 Objective Tree
 Pairwise
Comparison Chart
 Weighted Objectives
Tree
 Function-Means Tree
 Functional Analysis
 Requirements Matrix
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SPIRIT
 Literature Review
 Brainstorming
 User Surveys and
Questionnaires
 Structured Interviews
Building an Objectives Tree
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SPIRIT
Building an Objectives Tree
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SPIRIT
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.
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SPIRIT
What are Functions?
A
relationship between independent
variables (inputs) and response or
dependent variables. (outputs)
 Mathematics:
y  f x 
 Business
Management Theory:
Transformation function
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 labor 
 m aterials    products

  services 

technolog y  
SPIRIT
Black and Glass Boxes
 Like
the mathematical and management
models - relate the inputs to the
outputs
Black Box
 All
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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.
SPIRIT
Black Box of a Radio
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SPIRIT
Radio Glass Box
(the cover has been removed)
19
SPIRIT
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.
20
SPIRIT
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SPIRIT
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.
22
SPIRIT
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.
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SPIRIT
Conceptual Design
 Methods
 Means
 Performance
Specification Method
 Quality Function
Deployment (QFD)
 Morphological Chart
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SPIRIT
 Brainstorming
 Synectics and
Analogies
 Benchmarking
 Reverse Engineering
(Dissection)
Convergent (left brain) and
Divergent (right brain) Thinking
25
SPIRIT