The Engineering Design Process Mark D Conner The Engineering Academy at Hoover High School wwweahoovercom A good product is the result of a good process What is design Examples help What tools are available ID: 308435
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Slide1
Understanding & ApplyingThe Engineering Design Process
Mark D. Conner
The Engineering Academy at
Hoover High School
www.eahoover.comSlide2
A good product is the result of a good process.
What is design?
Examples help
What tools are available?
What is the Engineering Design Process?
+
+Slide3
Originality can be overrated.Slide4
What is Design?Slide5
Design is about creating – form and
function
.
It’s achieving
objectives within given constraints
.Slide6
The Engineering Design Process is an algorithm for creation and invention.Slide7
What is the Engineering Design Process?Slide8
The Engineering Design Process mirrors standard steps in problem-solving.
Documentation is crucial!Slide9
restrictions or limitations on a
behavior, a value, or some other
aspect of performance
stated as clearly defined limits
often the result of guidelines and
standards
actions the design must perform
expressed as “doing” statements
typically involve output based on
input
Define the problem in detail without implying a particular solution.
Problem Definition
desired attributes and behavior
expressed as “being” statements
(not “doing”)
non-negotiable objectives and/or
functions
Clarify design
objectives
Identify
constraints
Establish
functions
Establish
requirementsSlide10
Objectives, constraints, functions and requirements may be broad-based.
Some items are absolute – others may be negotiable
Functionality (inputs, outputs, operating modes)
Performance (speed, resolution)
Cost
Ease of useReliability, durability, securityPhysical (size, weight, temperature)
Power (voltage levels, battery life)Conformance to applicable standardsCompatibility with existing product(s)Slide11
Both functional and non-functional requirements may be placed on a design.
Functional
requirements:
support a given load
respond to voice commands(output based on input)
Non-functional requirements (usually form-focused):size, weight,
color, etc.power consumptionreliability
durabilityetc.Slide12
Establish
design
specifications
Generate
design
alternatives
Design involves creativity within boundaries. Consider
any
viable solution concept.
Concept
ual Design
precise descriptions of properties
numerical values corresponding
to performance parameters and
attributes
m
ust live within the design space
let the creativity flow
don’t marry the first idea
beware of “you/we can’t…” and
“you/we have to…”Slide13
determine the optimal design
Nail down enough design details that a decision can be made.
Preliminary Design
qualitative and/or quantitative
cardboard or scale models
computer models (CAD, FEM)
mathematical models
proof-of-concept
simulation results
“Flesh out” leading
conceptual designs
Model
,
analyze
,
test
, and
evaluate
conceptual
designs
“Flesh out” leading
conceptual designs
Model
“Flesh out” leading
conceptual designs
Model
,
analyze
“Flesh out” leading
conceptual designs
Model
,
analyze
,
test
“Flesh out” leading
conceptual designs
Model
,
analyze
,
test
, and
evaluate
conceptual
designsSlide14
The “optimal” design solution may or may not be obvious.
Design Decision
Select the
optimal
design
based on the findings
from the previous stageSlide15
Time to go from idea to reality.
Detailed Design
Refine and optimize
choices made in
preliminary design
Articulate specific parts
and dimensions
Fabricate prototype and
move toward production
There is a
huge
gulf between a great idea and a working prototype!Slide16
The Engineering Design Process is generally iterative, not linear.Slide17
How is the Engineering Design Process applied?(Part 1 – Asking Questions)
Context: BEST RoboticsSlide18
The design process begins with some initial problem statement.Initial Problem Statement
Design a robot to play this year’s game.
Design problems are often
ill-structured
and open-ended
.Asking questions is a great way to begin defining the problem to be addressed.Slide19
Think in terms of questions that would help define the problem and guide the design.
What scoring strategy will we use?
What type of steering is desired?
How many degrees-of-freedom does the robot need?
What maximum reach must the robot have?How fast does the robot need to be?
How much weight must the robot lift?What physical obstacles must the robot overcome?Will the robot be interacting with other robots?What sight (or other) limitations will be placed on the driver?
What functions must the robot perform?Slide20
Begin to categorize questions in terms of what information the answers communicate.
Clarifying
objectives
What scoring strategy will be adopted?
How much practice time will drivers have?Identifying
constraintsCan the robot touch other robots?Can game pieces touch the field?What are the dimensions of key parts of the field?
Establishing functionsWhat scoring strategy will be adopted?How much ground must the robot cover in a round?
Establishing requirementsWhat minimum size must the robot be to carry a given game piece?
How much weight must be lifted to carry a given game piece?
Problem DefinitionSlide21
Think about specific details and various means of achieving certain functions.
Establishing
design specifications
What is the maximum torque required to pick up a game piece?
What is the maximum reach needed?What is the smallest space in which the robot will operate?
Generating design alternativesCould the robot have 2, 3, or 4 wheels? Treads?
Could game pieces be lifted from above or scooped from below?
Conceptual DesignSlide22
What tools are available to aid in the Engineering Design Process?
How is the Engineering
Design Process applied?
(Part 2 – Some Tools to Guide the Process)Slide23
Some simple tools can help organize the design process.
Problem Definition
(Questions List)
Attributes List
Pairwise
Comparison Chart
Objectives/Constraints Tree
Conceptual Design
Preliminary Design
Design Specifications
6-3-5 Method
Function-Means TreeSlide24
An Attributes List contains a list of objectives, constraints, …
Objectives
Assemble primary subassemblies on the warehouse rack
Make no more than 2 trips into/out of the warehouse
Move planes to flight area (without hanging them)
Simple controlsConstraints
24 rules (size & weight)Less that 6 inches of clearance between racksApproximately 6 inches of clearance bringing the plane through the warehouse door
Driver doesn’t have depth perception w/r/t racks
Problem DefinitionSlide25
… functions, and requirements.Functions
Grab all 4 warehouse subassemblies (individually) with one grabber
Rotate fuselage 90 degrees
Zero-radius turning
Move FOD out of the way
RequirementsBe able to open the switchReach the top, back airplane piece
Support the weight of a fully assembled plane
Problem DefinitionSlide26
“0” if column objective > row objective“1” if row objective > column objectiveHigher score = more important
A
Pairwise
Comparison Chart
allows the designer to order/rank the objectives
Problem Definition
Goals
Speed
Drive
Power
Lifting
Power
DOF
Simple Controls
Score
Speed
••••
0
0
0
0
0
Drive
Power
1
••••
1
1
1
4
Lifting
Power
1
0
••••
1
1
3
DOF
1
0
0
••••
1
2
Simple Controls
1
0
0
0
••••
1Slide27
An Objectives/Constraints Tree provides a hierarchical view of key attributes.Slide28
Design Specifications refer to quantified values.
Wheel diameter = 8-10 inches
Degrees-of-freedom = 5
Minimum grabber spacing = 1 inch
Maximum grabber spacing = 4 inchesMaximum weight to be lifted = 18 oz.
Maximum vertical reach = 28 inchesMaximum horizontal reach = 12 inches
Conceptual DesignSlide29
The 6-3-5 Method is one way to begin generating design alternatives.
6 team members
3 ideas each (described in words or pictures)
5 other team members review each design idea
No discussions allowed during the process
Can be modified to N–3–(N-1)
Preliminary DesignSlide30
A Function-Means Tree shows means for achieving primary functions…and the fallout.
Preliminary DesignSlide31
A Function-Means Tree shows means for achieving primary functions…and the fallout.
Function
Means
Preliminary DesignSlide32
Are there any questions?