Transcript Linear Actuator Model

Automated Animal Board for
Positioning in Ocular
Photography and Imaging
Dhaval Desai
Nathan Kleinhans
Holly Liske
Laura Piechura
Kellen Sheedy
Client: B’Ann Gabelt
Department of Ophthalmology
Advisor: Wally Block, PhD
Department of Biomedical Engineering
Glaucoma
• High intraocular
pressure
• Damage of the
nerve fibers and the
optic disc
• Result: Vision loss
• Current cure: None
• Second leading
cause of blindness
in the world
Normal Vision
National Eye Institute
Vision with Glaucoma
National Eye Institute
Motivation
• Aim 1: Early diagnosis of glaucoma
– Nerve fiber layer thickness
– Normal vs. glaucoma
• Aim 2: Explore treatment options
– Chemotherapeutics and gene therapy
– Animal model: Monkey
– Monitor nerve fiber layer parameters at
several time points
Problem Statement
Fine adjustments in the positioning of the
eye are necessary to obtain quality
images of the retina and nerve for
glaucoma research. The goal of this
project is to construct an automated
positioning device that provides accurate
alignment of the animal for successive
scans.
Design Specification
• Automated or require minimal manual
labor
• Support weights up to 50 lbs
• Rotate 30 degrees from horizontal in pitch
and roll directions
Rotary Actuator Model
•Independent rotary actuators
–Control pitch and roll
•Automated rotation
•Inclinometer to measure angular
displacement
Rotary Actuator Model
Pros:
Cons:
• No center support of
plate required
• Low center of gravity
• Direct correlation to
handheld control
• Precision
• Torque on actuators
• Actuator cost
Ticker-Tape Model
• Mechanical approach
• Tape runs through platform in both directions
• Relies on system of internal pulleys
• Small motor retrieves tape (normalizes)
Ticker-Tape Model
Pros:
• Simple design
• Easy to record
displacement
• Inexpensive design
Cons:
• Manual
• Normalizing may
decrease life in
service
Linear Actuator Model
• Employs two
electric linear
actuators
• Ball and socket
heads are
mounted to
actuators
• Central ball and
socket column
• Inclinometer to
measure
angular
displacement
Linear Actuator Model
Pros:
Cons:
• Automated design
• Continuous motion
and fine adjustment
capabilities
• Complicated design
• Actuators and
inclinometers are
expensive
Design Matrix
Criteria
Rotator Ticker
Tape
Linear
Actuator
Accuracy
4
7
7
Maximum loads
6
4
9
Cost
2
8
5
Ease of
Manufacturing
6
4
6
Prototype Life
7
4
8
Total
25
27
35
Future Work
•
•
•
•
Final Design modifications
Choose and order materials
Build prototype
Test
References
• Glaucoma Research Foundation.
www.glaucoma.org
• National Glaucoma Research. American
Health Assistance Foundation.
www.ahaf.org
• Glaucoma Resource Guide. National Eye
Institute. www.nei.nih.gov/health
Questions?