Electrical Circuits I
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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)
1
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
4
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
5
SPIRIT
Attitude-Determining
Heuristics
Quantify
or express all
variables in numbers
Always give an answer
Work at the margin of
solvable problems
6
SPIRIT
Risk-Controlling Heuristics
Make
small changes from
previous successful
solutions.
Always give yourself a
chance to retreat.
Use feedback to stabilize a
design
7
SPIRIT
Resource Allocation
Heuristics
Allocate
8
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
12
SPIRIT
Literature Review
Brainstorming
User Surveys and
Questionnaires
Structured Interviews
Building an Objectives Tree
13
SPIRIT
Building an Objectives Tree
14
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.
15
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
16
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
17
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
18
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
21
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.
23
SPIRIT
Conceptual Design
Methods
Means
Performance
Specification Method
Quality Function
Deployment (QFD)
Morphological Chart
24
SPIRIT
Brainstorming
Synectics and
Analogies
Benchmarking
Reverse Engineering
(Dissection)
Convergent (left brain) and
Divergent (right brain) Thinking
25
SPIRIT