P12031: Motion Assistive
Seating Device for Sailing
Please view our Website for Live Updates:
http://edge.rit.edu/content/P12031/public/Home
Project Team:
Steven Gajewski
Aleef Mahmud
Mitchel Rankie
Christopher “Chappy” Sullivan
MSD - P12031
Faculty Guide: Edward Hanzlik
Technical Mentor: Kate Leipold
Primary Customer: Richard Ramos
Secondary Customer: Keith Burhans
Sponsor: Mark Smith and M.E. Dept.
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10/12/2011
Agenda
 Meeting Date:
Wednesday 11/4/2011 Desired Outcome from Meeting:
 Gather critical Feedback on our progress!
 Meeting Time:
 Are we headed in the right direction?
3:30PM-5:30PM
 Should we change anything before detailed design?
 Meeting Location:
RIT Engineering #09-4425  Interactive meeting: question or comment as we go!
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Project Description
Senior Design Project Data Sheet
Project #
Project Name
Project Track
Project Family
P12031
Motion Assistive
Seating Device for
Sailing
Biomedical Systems
and Technologies
N/A
Start Term
Team Guide
Project Sponsor
Doc. Revision
Fall
2011
Professor Edward
Hanzlik
RIT Funds
rev.1
Project Description
Project Background:
The goal of the Motion Assistive Seating Device
for Sailing team is to design, assemble, and test
an updated version of the current design for the
portable and detachable seating system that
empowers the disabled community to experience
the true joys of sailing while endowing the
functional advantages to compete in sailing
competitions and decreasing any hindrances
caused by implementing the seating system
during competition. The updated design should
be a safe and functional improvement upon the
current design that meets the requirements of
Richard Ramos and Keith Burhans. The updated
seating system will go into application for the
community of disabled users who wish to sail for
leisurely
purposes.
Depending
on
the
effectiveness of the design, the seating system
may receive enough recognition to go into further
implementation internationally through the
Paralympic games as was the current design
after its initial implementation.
Problem Statement:
The primary objective of this project is to make
improvement upon an existing design for
paralympian sailing events. Improvements are
desired in terms of lower weight and more
functionality.
Objectives/Scope:
1.
2.
3.
Reduce Weight
Increase and/or maintain the functionality
already available
Adapt specifically for C4-5 quadriplegic user
Richard Ramos on a 3 person Sonar keel
boat and must meet all IFDS regulations
Deliverables:
MSD - P12031



Analysis
3 and Modeling of current system.
Functional prototype that meets the needs.
New Design, Drawings (i.e. Cad), Sketches,
Analysis (i.e. FEM), and BOM on prototype.
Expected Project Benefits:



Recognition to RIT Mechanical Engineering.
Tremendous impact on the disabled
community by empowering them to live more
active lifestyles like Richard Ramos.
Excellent hands on learning in product
development of medical devices and
performance sailing.
Core Team Members:




Steve Gajewski
Aleef Mahmud – Project Manager
Mitchel Rankie
Christopher Sullivan – Systems Engineer
Strategy & Approach
Assumptions & Constraints:
1.
2.
3.
4.
5.
The team must first understand current
system and sailing interfaces. Working with
an existing system will enable the team to
properly complete their analysis prior to
design of the updated system.
Proposed Budget: $1000
System must fit Sonar model sailing boat.
Solution must utilize materials and methods
that are appropriate for Marine/Sailing
applications.
Solution must comply with all appropriate
requirements and regulations.
Issues & Risks:
Project Issues/Risks/Constraints

Project Comprehension by Team
o New Project
o New Area of Study for Many

Available Resources
o Obtaining Resources
o Order Parts/Hardware
o Lead Time

Time and Performance risks
o Design is safe in operation.
o Design deliverable within 22 wk.
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Customer Needs
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Engineering Specifications
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Material Selection
 Ideal material:




High corrosion resistance
High strength properties
Weld-able
Common
 AA 6061-T6:
 Has all material qualities we are looking for
 Very common across all distributors
Material
Modulus
Poisson’s
AA 6061-T6
70-80
0.33
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Tensile
Strength
115
Yield
Shear
48
83
6
Cost (12"x1"x1")
[McMaster]
$6.32
Weld able
Yes
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Recap: Functional Decomposition
User
Device
Portability
Attachable
Non
Permanent
Tiller
Control
Assembly
Required
Override
Major Parts
Tiller Strut
Tiller Arm
Rotate hand
Crank
Passenger
Interface
Seat
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Shifting
Weight
Ropes Taut
Track
Platform
Boat
Ropes and
Pulleys
Locking
Mechanism
4-Point
harness
Restrain
User
Hands
Feet
Steering
column tilt
Pedestal
Base
Cranks
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Recap: System Interface
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Detailed Design
 Safety
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 Triple Constraint
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Pedestal Base
 Pedestal base changes
 Re-routed lines (new pulley location)
 Taller support tube
 Shorter platform
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Track Platform
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Material Properties
Young’s
Modulus
200 GPa
70.0 GPa
Structural Steel
Aluminum T6
(MatWeb)
Plywood (The
1.6GPa
Engineering ToolBox)
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Yield
Ultimate
Density
250MPa
270 MPa
460MPa
395MPa
2823 kg / m3
N/A
50 MPa
600 kg / m3
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Richard Swinging Across
𝜃
𝜋 − .0001
=
0
𝜃
𝜃=𝜃
−𝑔 sin 30 sin 𝜃
𝜃=
𝑅 sin 𝜃 2 + 𝑅 cos 𝜃
1
0.8
0.6
0.4
0.2
2
0
-0.2
-0.4
-0.6
-0.8
-1
-1
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-0.5
0
0.5
1
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Richard Swinging Across
𝑣𝑅 = 3.7 𝑚 𝑠
𝑣𝑅 = −8.2 𝑚𝑝ℎ
1 2
𝑣𝑟 𝑚
2
𝐹𝑐 =
𝑑
𝐹𝑐 = 6000𝑁
Angular Velocity vs Time
0
Angular Velocity (rad/s)
-1
-2
-3
-4
-5
-6
1
1.5
2
2.5
3
3.5
Time (s)
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ANSYS Work for Richard Swinging
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Rough Waves
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Rough Waves
7
Wave
6
𝑦𝑚𝑎𝑥
2𝜋𝑡 𝜋
𝑦𝑚𝑎𝑥
𝑌𝑤 𝑡 =
sin
−
+
2
𝑃
2
2
5
Hight
4
3
1
2
Angle Of the Boat
0.8
1
0.6
0
0
2
4
6
0.2
8
Time (s)
10
12
14
16
0.8
0
-0.2
0.6
-0.4
0.4
-0.6
-0.8
-1
0
2
4
6
8
Time (s)
10
12
14
16
Acceleration (m/s 2)
Angle (rad)
0.4
0.2
0
-0.2
-0.4
1425N-down
25N-Bow
-0.6
-0.8
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Acc Y
Acc X
17
0
2
4
6
8
Time (s)
10
12
14
16
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Rough Waves
At Stop
At Unsupported
At Middle
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Acceleration
 The Maximum
acceleration the system
can handle 4.5 Gs
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Acceleration
Bow 5G
Stern 4.5G
Port 5G
Bow 10G
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Starboard 4.5G
Combined Starboard
and Sten3.5G Mag = 4.9
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Passenger Interface
 The Passenger Interface is a
very elaborate subsystem that
was further dissected into two
sub-subsystems:
Crank System
Seating Support
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User Dimensions
 Passenger Interface was
heavily driven by the user’s
dimensions.
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Custom Seat Dimensions
“ASO seat pan will be 19 wide x 18 long and about 4" tall” Colleen Wolstenholm, Aspen Seating LLC
“Seat pan will have a t-nut fastener heated and sunk into
the seat on the inside plastic, then a 1/4-20 stainless knob
screwing from the outside of the aluminum tabs to the
seat.” - Joe Bieganek, Aspen Seating LLC
Aluminum tabs can be welded on to seat plate once we have
access to the Custom Seat to align with the bolt location.
 Waiting for more details on the custom seat.
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Benchmarking: Seat
The Parameters for choosing the seat:
 Seat must fit within a common interface with the Custom Seat.
 Interface will be aluminum flat plate with the dimensions of 20”wide by 18”long.






Seat Height cannot exceed 30”
Seat must fit within the boundaries of the Sonar Boat.
Seat must have minimal weight.
Seat must be durable in corrosive environment.
Seat must be intended for rigorous activity.
Seat cost must be relatively low compared to the market.
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Benchmarking: Seat
Kirkey 19800 Economy 10 Degree Layback
 Versatile mounting.
 17.5”wide by 14.5”long by 35”high with
10⁰recline.
 Weighs 13.5lb
 Al 5052 has good formability, corrosion
resistance and weldability.
 Designed for low horse power cars on
small tracks.
 Stock frame costs $136.60 and the Blue
Vinyl cover cost $68.40. Total estimate
is about $205.
 Catalog:
http://kirkeyracing.com/Kirkey_2009_c
atalog.pdf
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Benchmarking: Harness
The Parameters for choosing the seat:





Harness must fit with the Custom Seat and Commercial Seat.
Harness must restrain user within the confines of the seat.
Harness must be accepted by user for final application.
Harness must be durable in corrosive environment.
Harness cost must be relatively low compared to the
market.
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Benchmarking: Harness
enableyourlife.com Wheelchair Butterfly
Chest Harness
 Harness intended to attach via 4” adjustable
straps which can be mounted on the seat.
 Harness is designed to restrain disabled users
into their wheel chairs while in movement.
 User has already voiced his preference for
butterfly type harnesses.
 Harness material is a versatile nylon webbing
and plastic buckle that should not rust.
 Harness cost is very low compared to its
competitors.
 Catalog:
http://enableyourlife.com/wheelchairbutterfly-chest-harness.asp
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Hand Constraints & Attachment
 Used C-5 Grip system as
benchmark
 System too expensive to
purchase
 Decided to redesign and
fabricate
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Our “C-5” System
Hand
Tube
Pin Hole
 Same functionality
 Cheaper components
 Simple solution
Bearing
Threaded
Insert
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Casing
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Bearing Specifications
Max Dynamic Load
Max Static Load
Max Axial Load
2110
966
966
lb
lb
lb
 Sealed bearing to last in
elements
 Able to withstand larger loads
than applied
 Cheap to replace if needed
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Boat Constraints
 Needed to know boat
dimensions to design
everything
 Shumway provided non
dimensioned drawing
 Took real world measurements
to scale drawing
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Boat Constraints Cont.
 From dimensions we scaled
drawing
 Created the boat itself to make
sure system fits inside
 Created a hybrid 3-D drawing
to show walls and important
features on boat
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Boat Constraints Cont.
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Seat Tilt and Support
 Once boat was laid out
design was possible
 Decided on permanent
tilt for simplicity
 Went with 10 degree tilt
for comfort and visibility
 Seat has built in seat so
you are actually tilted 20 25 degrees
MSD - P12031
 Decided to keep the back
of bar in same location
 Raised front where
pedestal mount is
 Therefore system needed
to shift forward to
prevent contact with
sides and traveler
 With tilt total height will
decrease to miss boom
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Seat Tilt Prelim Design
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Seat Support Design
 Once angle and structure was decided we laid out our
support system
 Single beam for simplicity
 Cross beam for support and bearing mount
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Crank Geometry Constraints
 Crank center of rotation
was to be placed at
location relative to seat
 Distance between pulleys
was fixed by v-belt length
 Width of crank fixed by
Richard’s dimensions
 Seat was a large factor
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 Seat issues:
 Seat drives where crank is
 Different seats move
crank (different
dimensions)
 Where seat plate is
located
 Tilt created difficult
geometry
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Crank Center Location
 Crank located 23” from
back of seat and 12” from
seat cushion
 Assumed 11” torso and
14” from torso
 Used 23” so there is play
and space for different
seats
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Crank Layout Design
 Used Callahan’s system
for layout
 Shaft set up allows for
line drum to rotate as
well as steering system to
rotate out of the way
 Support arm provides
strength and constrains
rotation of system
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Crank Layout Cont.
 Centered line drum over
pedestal
 Secured support arm with
ball lock pin for easy
installation
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Points of Adjustability
 To change crank location the following dimensions must
be changed
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Adjustability Cont.
 Grip system will have longer or shorter hand tubes
for different should widths
 Seat can be moved relative to the plate
 Harness size can be changed
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Calculation: Mechanical Advantage
Mechanical Advantage:
User input force will be amplified
through the pulleys and crank sizes.
Current system amplifies to
approximately 85lb output.
Current system will amplifies to
approximately 150lb output.
 Approximately 75% increase
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Calculation: Seat Plate
Seat Plate:




Aluminum 6061-T6
20”wide by 18”long by .25”thick
Analyzed through use of ANSYS Classic.
Assume Fixed Support at weld and cross
beam.
 Case #1: Assume distributed Pressure P
across entire plate to represent Richard’s
𝐹
weight of 170lb in normal position. 𝑃 = 𝐴 =
𝐹
𝑊𝑥𝐿
=
170𝑙𝑏
20𝑖𝑛x18in
= .4722𝑃𝑠𝑖
 Case #2: Assume distributed Pressure P
across half the plate to represent
Richard’s weight of 170lb suddenly thrown
to one side while in quick rotation. 𝑃 =
𝐹
2𝑥𝐹
2𝑥170𝑙𝑏
= .9444𝑃𝑠𝑖
𝐴 = 𝑊𝑥𝐿 =
20𝑖𝑛x18in
(2)
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Calculation: Seat Plate
 Final conclusion is that the seat will be able to
withstand the loading under its current
specifications in ideal conditions. No further
redesign is recommended at this time.
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Calculation: Crank System
Crank System:
 Aluminum 6061-T6
 Analyzed through use of ANSYS
Workbench.
 Assume Fixed Support at connection
points.
 Case #1: Normal 20lb applied by user on
the crank axis.
 Case #2: Extreme case of 170lb applied
by user on the crank axis to represent his
entire weight being pulled against the
crank system.
 Case #3: Extreme case of 170lb applied
by user on the crank axis to represent his
entire weight being pushed onto the
crank system.
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Calculation: Crank System
 Final conclusion is that the Crank System will
be able to withstand the loading under its
current specifications. Despite being loaded
in the most aggressive scenarios to simulate
the entire weight of the user being slammed
against and pulled away from the crank, the
crank system will still be able to withstand
the load.
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Calculation: Original Tiller Strut
Original Tiller Strut :
 Aluminum 6061-T6
 Analyzed through use of ANSYS
Workbench.
 Assume Fixed Support at
connection points.
 Case #1: Previous load of 85lb on
previous design.
 Case #2: Enhanced load of 150lb on
previous design.
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Calculation: Crank System
 Final conclusion is that the Tiller Strut will
not be able to withstand the Enhanced load
of 150lb generated through mechanical
advantage of the new proposed design. Steps
must be taken to redesign the Tiller Strut as
well to withstand the new load generated in
the new design.
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Calculation: Tiller Strut Redesign
Tiller Strut Redesign :
 Aluminum 6061-T6
 Beefed up with Aluminum
tubes.
 Analyzed through use of ANSYS
Workbench.
 Assume Fixed Support at
connection points.
 Case #1: Simulates the boat
going straight under peak load.
 Case #2: Simulates the boat
turning left under peak load.
 Case #3: Simulates the boat
turning Right under peak load.
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Calculation: Crank System
 Final conclusion is that the new Tiller Strut
design will be able to withstand the
Enhanced load of 150lb generated through
mechanical advantage of the new proposed
design. The implementation of the square
tubes should also work to limit the
deformation caused by the accentuated
loading to less than 1/8”.
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Preliminary Test Plan
Major Sub-Systems/ Features/ Function
1 Weight and Cost
2 User Comfort
3 Installation
4 Normal Sailing Conditions
5 Rough Sailing and Worst Case Conditions
6
7
General Template for Testing
Function/ Feature Name:________________
Date Completed: _________________
Performed By: __________________
Tested By: ________________________.
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Preliminary Test Plan Cont.
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Preliminary Test Plan Cont.
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Project Plan: MSD I
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Project Plan: MSD 2
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Risk Assessment 1
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Risk Assessment 2
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Risk Assessment 3
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Risk Assessment 4
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Next Step
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Questions and Feedback
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Unknowns and Action Items
 For Richard Ramos:
 For Keith Burhans:
 Status of custom seat
 Timeframe for current
system return
 Probably reach BOM cost
of $3000
 SONAR availability during
Winter for testing phase
 For all Stakeholders:
 Are we headed in the right
direction?
 Should we change anything
before detailed design?
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