Design of a Stabilizing Handle for Parkinson’s Disease Patients - 1

ME407 – Mechanical Engineering Design | Spring 2019 | Group G2
Mock-up Presentation
Onur Bozkurt
Samet Baykul
Barış Polat
Aziz Emre Akgündüz
Atakan Botasun
Doğa Volkan Altundağ
Mahmut Demir
Ginaz Almus
Design of a Stabilizing Handle for
Parkinson’s Disease Patients

31Overview
• Problem Definition
• Functional Decomposition
• Morphological Chart
• Concept Evaluation
• Best Concept
• Detailed Geometric Layout
• Proof of Concept
• Experience Gained from Mock-up
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31
Problem Definition
• A handle mechanism is to be
designed for PD patients to assist
them in fulfilling their needs in daily
life without the involvement of any
pharmaceutical treatments.
• The handle mechanism is to create
the means of consuming food
without any external assistance,
thus the shaking motion on the
handle side must be eliminated
from the tip of the utensil.
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Figure 1: Liftware Steady, an already existing commercial
product for the problem.

31Functional Decomposition
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Table 1: Functional
Decomposition Chart

5
31
Concept
Evaluation
Evaluation Criteria
Vibration Isolation
Ease of Cleaning
Working Duration Condition
Weight Constraints
Volume Constraints
ON/OFF Switch
User Friendliness
Life Cycle
Reasonable Manufacturing Cost
Electrical Packaging
4/15/2019Mock-up Presentation

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31
Concept
Evaluation
Table 3. Normalized Weighted Factors

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31
Concept
Evaluation
Our concepts
Concept 1: Servomotor, clamp, rechargeable battery, soft fabric for a firm
grip, a magnetic clip mechanism, ON/OFF switch for an active system, symmetric
handle.
Concept 2: Spring-damper mechanism, clamp, viscoelastic cover, a Delrin clip mechanism,
symmetric handle.
Concept 3: DC or Servomotor, round clamp, viscoelastic cover, a screw mechanism,
symmetric handle.
Concept 4: Hybrid active-passive system, round clamp, ON/OFF switch with hand
band, a Delrin clip mechanism, symmetric handle, replaceable battery.
Concept 5: Spring-damper mechanism, clamp, a screw mechanism, symmetric handle,
soft fabric for a firm grip.
Concept 6: Magnetic repulsion, clamp, a screw mechanism, symmetric handle, soft fabric
for a firm grip, rechargeable battery, ON/OFF switch for the active system.
Concept 7: Hybrid active-passive system, round clamp, viscoelastic cover, a Delrin clip
mechanism, symmetric handle.
Concept 8: Counterweight-spring, round clamp, soft fabric for a firm grip, magnetic clip,
symmetric handle.

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Concept
Evaluation
Table 4. Evaluation of the overall concepts

31
Best Concept
• Components: Spring-damper mechanism, clamp,
viscoelastic cover, Delrin clip for attachments,
symmetric handle.
• To attach or detach the spoon, a Delrin
clip mechanism has been chosen. Delrin clips are
relatively easy to manufacture and use. ET/PD
patients can easily assemble or disassemble the
handle from the utensil as the action is just a simple
push. Delrin clips are widely used in many different
areas like bag strap buckles, so the users will be
quite familiar with the concept. The vibratory
isolation will be carried out by a spring on both axes.
Viscoelastic pads will assist by dissipating vibratory
behavior, and constant force springs will negate the
adverse effects of gravitation.
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Figure 2: Drawing of the best concept

31Design Criteria
• Reduction in amplitude (0.5 Hz, 1.2 Hz, 1.5 Hz)
• Ease of cleaning/being dishwasher-safe (for attachments)
• Working duration condition (15 mins x 3 meals)
• Weight constraints
• Volume constraints
• On/Off Switch
• User friendliness, ergonomic design (hand mold grip etc.) and reasonable surface
temperature
• Life cycle (1000 hours)
• Electrical packaging
• Reasonable manufacturing cost
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31
Drawings
Figure 3
Rod Assembly
Male Delrin clip built into the
rod
Springs attached to the rod via
a shaft collar which is attached
to the rod by pins
Another collar used to fix the
rod to the spherical joint
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31
Drawings
Figure 4
Spherical joint and
constant force spring
mount
Representative mount used in
sketch for the constant force
spring drawing found – the real
mount will also include a spool
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31
Drawings
Figure 5
Spoon Attachment
Female Delrin clip built into the
utensil attachment
Mass added onto the
attachment so that it moves
closer to the tip
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31
Drawings
Figure 6
Springs and pins
Springs directly hooked onto
the body by swivel hooks
latched onto holes on through
pins (on the ring collar) and
body
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31
Drawings
Figure 7
Viscoelastic cover
Ergonomic cover for the handle
body for better and
comfortable grip
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31
Drawings
Figure 8
Section view
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Spoon
bowl
Mass Delrin
clip
Spring
Constant
force
spring
Ball jointCollar
Shaft collar

31
Drawings
Video 1
Exploded view and
collapsing of the assembly
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31Proof of Concept
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L
r
m
k c
θ
O
x(t)
y(t) = Yoeiwt
Assume small oscillations.
Constant force spring eliminates the restoring
effect of gravity.
Figure 9: Free-Body
Diagram of the Setup

31Proof of Concept
Video 2
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Video 2: Mock-up setup
Proof of concept demonstration

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20Simulations
Videos 3,4,5

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21
Figures 5,6,7:
Frequency Response – Harmonic Solution (Y top, X bottom)
Results from ANSYS simulations.
0.5 Hz 1 Hz 1.5 Hz
Simulations
Figures 5,6,7

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22Simulations
Tables 5,6,7
Table 5: Spring forces (Y) - Harmonic Solution
Table 6: Spring forces (X) - Harmonic Solution

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23Simulations
Tables 5,6,7
Table 7: Amplitudes - Harmonic Solution

31
The Setup
• Not: figure numaralarını güncelleyin.
Dört tane varmış gibi yaptım.
Fazlaysa ekleyin, azsa çıkarın.
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31
The Setup
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31Remarks on Gained Experience
Figures 14,15:
Mock-up photographs - Helical spring
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Problem – Tension spring not
operational under compression
Solutions:
• Usage of tension-compression
springs
• Attaching tension spring with
initial deflection

Problem – Constant force spring
cannot be tied to the rod by a
string
Solution – Usage of a screw
Problem – Constant force spring
unfurls and twists frequently
Solution – Usage of a spool
Figures 16,17:
Mock-up photographs – Constant force
spring
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Constant force springs
can be also aligned
back-to-back for
improved stability.
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Figure 18 – Dual back-to-back
arrangement of constant force
springs.
Source: Spring-I-Pedia,
http://springipedia.com/constant-
force-mounting.asp

Problem - Dry friction caused by constant force spring and crudely assembled
elements – detrimental to isolation
Solutions:
• Use an additional safety margin for the isolation goal
• Use cleaner design
• Adjust placement distances accordingly
• Change mass accordingly
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Assembly and calculation steps:
• Major factor in our decisions – constant force spring output (distinct values)
• Second factor in our decisions – spring stiffness
• Selected according to the weight selection
• Calculate the placement locations, also considering geometric constraints
• Carry out final tunings to the weight or its placement to alleviate dry friction
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31
Thank you for listening!
Questions?
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Design of a Stabilizing Handle for Parkinson’s Disease Patients - 1

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