Understanding

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Understanding ApplyingThe Engineering Design
Process

• Mark D. Conner
• The Engineering Academy at Hoover High School
• www.eahoover.com

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A good product is the result of a good process.


What is design?
What is the Engineering Design Process?
Examples help
What tools are available?
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Originality can be overrated.
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What is Design?
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Design is about creating form and function.
Its achieving objectives within given
constraints.
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The Engineering Design Process is an algorithm
for creation and invention.
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What is the Engineering Design Process?
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The Engineering Design Process mirrors standard
steps in problem-solving.
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Define the problem in detail without implying a
particular solution.
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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 use
• Reliability, durability, security
• Physical (size, weight, temperature)
• Power (voltage levels, battery life)
• Conformance to applicable standards
• Compatibility with existing product(s)

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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 consumption
• reliability
• durability
• etc.

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Design involves creativity within boundaries.
Consider any viable solution concept.
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Nail down enough design details that a decision
can be made.
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The optimal design solution may or may not be
obvious.
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Time to go from idea to reality.
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The Engineering Design Process is generally
iterative, not linear.
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How is the Engineering Design Process
applied?(Part 1 Asking Questions)

• Context BEST Robotics

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The design process begins with some initial
problem statement.

• Initial Problem Statement
• Design a robot to play this years game.
• Design problems are often ill-structured and
  open-ended.
• Asking questions is a great way to begin defining
  the problem to be addressed.

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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?

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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 constraints
• Can the robot touch other robots?
• Can game pieces touch the field?
• What are the dimensions of key parts of the
  field?
• Establishing functions
• What scoring strategy will be adopted?
• How much ground must the robot cover in a round?
• Establishing requirements
• What minimum size must the robot be to carry a
  given game piece?
• How much weight must be lifted to carry a given
  game piece?

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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 alternatives
• Could the robot have 2, 3, or 4 wheels? Treads?
• Could game pieces be lifted from above or scooped
  from below?

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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)

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Some simple tools can help organize the design
process.
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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 controls
• Constraints
• 24 rules (size weight)
• Less that 6 inches of clearance between racks
• Approximately 6 inches of clearance bringing the
  plane through the warehouse door
• Driver doesnt have depth perception w/r/t racks

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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
• Requirements
• Be able to open the switch
• Reach the top, back airplane piece
• Support the weight of a fully assembled plane

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A Pairwise Comparison Chart allows the designer
to order/rank the objectives

• 0 if column objective gt row objective
• 1 if row objective gt column objective
• Higher score more important

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 1
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The Objectives-Constraints Tree groups objectives
and constraints in a hierarchical form.
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Design Specifications refer to quantified values.

• Wheel diameter 8-10 inches
• Degrees-of-freedom 5
• Minimum grabber spacing 1 inch
• Maximum grabber spacing 4 inches
• Maximum weight to be lifted 18 oz.
• Maximum vertical reach 28 inches
• Maximum horizontal reach 12 inches

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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 N3(N-1)

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A Function-Means Tree shows means for achieving
primary functionsand the fallout.
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A Function-Means Tree shows means for achieving
primary functionsand the fallout.
Function
Means
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Are there any questions?