P14045: Mobile Pediatric
Stander
System Design Review
Agenda
● Introduction
●
●
●
●
●
●
●
●
●
●
●
Background/Problem statement
Customer Requirements
Engineering Requirements
Benchmarking Specs
Functional Decomposition
Concept Generation/Selection
System Architecture
Risk Assessment
Engineering Analysis
Test Plan Outline
Project Schedule
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2
Who’s who?
Greg Roeth: Project
Manager/Mechanical
Engineer
Alex Hebert: Lead Mechanical
Engineer
Emily Courtney: Mechanical
Engineer
Martha Vargas: Lead Electrical
Engineer
John Daley: Electrical Engineer
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Project Background
Who will use our mobilized standers?
● Predominantly pre-school kids with Cerebral Palsy (CP)
•
CP is a “non progressive brain disorder” caused by damage to a
developing brain
o disconnection between muscles and the brain

•
wide range of motor skills/control
o condition typically doesn’t worsen or improve over time
Some users are on the Autism spectrum as well
*taken from familymedicinehelp.com
14045 Week 6 Project Presentation - 10/1/13
*taken from cprochester.org
4
Project Background
What is a mobile pediatric stander?
•
•
•
Teaching Style:
- Push In vs. Pull Out
Happier Kids
Physiological and psychological
benefits to standing vs. sitting
14045 Week 6 Project Presentation - 10/1/13
Snug Seat Product Guide 2013
5
Project Background
Problem Statement:
● A motorized pediatric stander is a device similar to a wheelchair, meant to
assist a disabled child to move around their environment in an upright
position. The device should be able to provide safe, comfortable, and
smooth transportation of the passenger, with the ability to be controlled
by a third party. A previous prototype used buttons to control its
movement, but the start/stop was found to be very jerky and the stander
did not track straight. The remote control functionality was attempted,
but was not fully implemented. Safety features were not fully developed.
● The goals for this project are to modify the existing prototype to include
better safety features such as collision detection and a remote control for
a third party. Since there are no standing patents on automated standers
key constraints are cost and weight of the components we add.
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Customer Requirements
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Benchmarking Old Systems
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Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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http://images.worldofapple.com
/
https://www.ssidisplays.co
m/
http://www.etac.com/
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Control System Mounting
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Gooseneck Arm
Pros:
● Avoids sharp corners adjustable
● Multi Size
Cons:
● potential break down
● weight restrictions
http://www.1800wheelchair.com/
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Swivel Arm
Pros:
● Fully Adjustable
Cons:
● Limited Orientation
● iPad only
http://www.rehabmart.com/
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Snug Seat Tray
Pro:
● wide workspace
Cons:
● Fixed
● Doesn’t move out of the way
● toucan only
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Concept Selection Process
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Final Concept
● Magnetic tray
● Swappable
Touchpad/iPad
● Collapsible
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Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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Electronics Housing Current Design
Pros:
1) Battery is secure
Cons:
1) Components and wires
are exposed
2) Battery tray is rusty and
sharp
3)Battery tray in way of
stander angle adjustment
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Electronics Housing - Option 1
Pros:
1) Battery is secure, yet accessible
2) One box, One location
3) Baffles allow airflow and provide spill
protection
Cons:
1) Need to create
mounting area
2) May interfere
with folding control
mount
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Electronics Housing - Option 2
*taken from123rf.com
Pros:
1) All components
contained and separate
2) Utilizes available
mounting space
3) Utilizes current battery
tray mounting
Cons:
1) Multiple
parts, multiple
locations
(3)
*taken from ozprodrivers.com.au
*taken from tadpoleadaptive.com
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a.
Electronics Housing - Option 3
b.
+
Pros:
1) Battery is secure, yet
accessible and separate
2) One location - utilizes
current tray mounting
Cons:
1) Cumbersome - may
interfere with angle adjust
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Electronics Housing Concept selection
vs.
vs.
vs.
vs.
+
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Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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Wheel System
Current Design:
Pros:
● Already implemented on stander.
● Integrates well with parallax
motor bearing block.
Cons:
● Stander had to be roughly
modified for assembly.
● Assembly and stander adaptation
is difficult.
We would like to implement a
solution that integrates with the
stander and the motor mounts in
an easier way.
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New Wheel Mount Concepts
Concept 1: New Bracket
Pros:
● More easily attaches to
stander
● Doesn’t require
modification to stander
parts
Cons
● Potentially difficult to
manufacture
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New Wheel Mount Concepts
Concept 2: New Adapter
Pros:
● More easily attaches to
stander
● Doesn’t require
modification to stander
parts
● Utilizes existing adapter
block
Cons:
● Potential difficulty of
assembly.
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New Wheel Mount Concepts
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New Wheel Mount Concepts
● From the preliminary Pugh charts, it
seems like the new adapter is the way
to go.
● Still to-do
○ Measure existing stander mounts
○ Perform preliminary engineering analysis
on current designs.
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Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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Microprocessor
Last Year’s Group: Stellaris
●
●
●
Fully developed Board, lots of unnecessary additions
Used Ti’s Code Composer
Expensive, mitigated by the MCU contest (now finished)
Contenders
Launchpad - Stellaris or MSP430
●
●
●
TI products - similar to last years group
Cheap
Lots of add-ons, lots of support
Arduino
●
●
Lots of add-ons
Extensive libraries, easy to use
Raspberry Pi
●
●
single board computer (overkill)
Linux environment
STM32 F3
●
ARM processor similar to last years
*image from mouser.com
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Microprocessor
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*images from wiki.ti.com, en.wikipedia.org, jaunty-electronics.com, bit-tech.net
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Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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Bluetooth Module
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Images from robotshop.com,, processors.wiki.ti.com/, bluegiga.com,, and sparkfun.com,
35
Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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Control Scheme Pugh Concept Selection Decision Matrix
Cited Sources:
Imageshttp://www.etac.com/uploa
d/NL-Etac/E800/Wheelchairaccessories-R-NET-ControllerJoystick-36-0.jpg
http://img.diytrade.com/cdimg/146
0607/22277139/0/1309847401/Pr
ogrammable_Control_System_Wir
eless_Touch_Screen.jpg
https://www.ssidisplays.com/sites/
default/files/img_2352.jpg
http://images.worldofapple.com/
http://i01.i.aliimg.com/wsphoto/v0/
1246873025_1/6-pcs-of-60mmlighted-font-b-button-b-font-font-bIlluminated-b-font-round.jpg
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Remote Control
● Custom design based on P13045.
● Reduce size and adapt
ergonomically to user.
● Use same uController as
main system.
Last year’s model consisted on a TI Stellaris
Launchpad controller encased in a box with 5
buttons and two switches.
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Concept Selection
●
●
●
●
●
●
Control System Mounting
Electronics housing
Wheel System
Microprocessor
Bluetooth Module
Control Scheme
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System architecture: Level 1
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Risk Assessment
ID
Risk Item
Effect
Cause
Action to Minimize Risk
Owner
1
Damage to electronics
Loss of injured
component, increase in
cost to replace items
Overloads, water, blunt
force trauma, gunshots,
angry group members
Work on electronics in a lab and use proper
ESD protection, design protective casing,
Perform weather test very carefully and
without electronics.
Group split
2
Motors don’t drive
straight
User had to
compensate, or
device is unusable
Poor software
development
1
3
3
Proper testing
EEs
3
Damage to stander
Increased cost/time
Crashing, improper
operation, ill
considered
modifications
1
3
3
Proper planning and testing only in
controlled environment, design reviews
before proposed modifications,
Group split
4
Injuring user
Loss of test subject,
possible end of
project, lawsuit
Improper operation,
improper design
1
3
3
Design correct specs, tests of
modifications, tested by dummy before
patient
Group split
5
Injuring bystander
Possible end of
project, lawsuit
Improper operation,
improper design
1
3
3
Design correct specs, test in controlled
environment
Group split
6
Software is buggy
Device could not
function, could just
have quirks
little experience in
programming
2
2
4
Have expert review over software, pull
in extra resources around RIT
EEs
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L
S
3
I
2
6
43
Risk Assessment (Cont.)
ID
Risk Item
Effect
Cause
L
S
I
Action to Minimize Risk
Owner
7
Work not completed
on time
Loss of time and
goodwill in group,
failure to complete
project fully
Poor planning and
time management
2
3
6
In depth project plan that is FOLLOWED
Everyone
8
Lack of funds
Can’t buy
components
overspending, lack
of support from
sponsor
1
2
2
Good project plan, very awesome faculty
guide
Leads
9
Inconsistent team
priorities
Wasted time and
money, interpersonal
tension
Lack of team
values, poor
communications,
poor
management/planni
ng
1
2
2
Weekly meetings
Leads and
Guides
10
Customer changes
mind in focuses
Wasted time, product
does not satisfy
customer
Poor
communication with
Linda/Steve, bad
problem statement
1
3
3
Meet with Linda and Email her on major
project updates and major branches of
development
11
Conflicting customer
ideas
Compromises that
leave everyone
dissatisfied
Poor
communication
between Linda and
Steve
3
1
3
Include Dr. Day and Linda on meetings
and design reviews, encourage dialogue
in email
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Risk Assessment (Cont.)
ID
Risk Item
Effect
Cause
L
S
I
Action to Minimize Risk
12
Processor Change
Loss of time due to
changed code, more
money and
development costs
Choice made too
quickly and too
early in
development
1
2
2
Make code in higher level language, such
as C instead of assembly
13
Tipping
Injuring user,
damage to stander,
especially upper
portions
Poorly thought out
modifications, too
much acceleration
1
3
3
Do better testing and survey the usage
site. Make sure deceleration is not very
large, govern the speed.
14
Battery Overheating
Damage to
Electronics
Poor Airflow, too
much insulation
and overuse
1
3
3
Monitor temperature, thermal shut offs,
good enclosure design, don’t use a li-po
15
Dangerous Stander
Design
Injuring user
Sharp edges and
loose connection
(electrical and
mechanical)
2
2
4
No sharp edges, check all electrical
connections that no powered surface is
accessible
16
Long lead time on
parts
Delay of project due
to lack of parts so no
testing, design,
building
Long lead time from
manufacturers,
parts out of stock
2
2
4
Order early, order often, have
alternatives for things to work on, do fab.
work in house
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Owner
45
Engineering Analysis
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Test Plan Outline
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Test Plan Outline
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Project Schedule
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Agenda
● Introduction
●
●
●
●
●
●
●
●
●
●
●
Background/Problem statement
Customer Requirements
Engineering Requirements
Benchmarking Specs
Functional Decomposition
Concept Generation/Selection
System Architecture
Risk Assessment
Engineering Analysis
Test Plan Outline
Project Schedule
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Questions?
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