Transcript Catheter Guidewire Control System

Catheter Guidewire Control
System
Derek Carlson & Caleb Anderson
Advisors: Dr. Dempsey & Dr. Stewart
Contents
• Caleb Anderson
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Overview of Catheterization
Project Summary
Overall Block Diagram
Electroactive Polymer
Polymer data
Platinum vs. Gold
• Derek Carlson
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Motor Controller Board
Stepper Motors
MATLAB progress
GUI
Updated Equipment List
Updated Foreseeable Difficulties
Schedule
Collaborative Progress w/ ME’s
Questions?
Overview of Catheterization
• Currently requires the use of
multiple guidewires
• Guidewire allows easy travel to
area of blockage
• Catheter slides directly over
guidewire
• Guidewire is then removed from
vessel
www.forsythradiology.com
www.amplatzer.com
Project Summary
• Eliminate the need for different guidewires
• Add precision control to the guidewire itself.
• Add remote control to the guidewire simply by viewing the
patient through a camera.
• Control will be implemented using a joystick interfaced
with MATLAB
• A purchased controller board will run two stepper motors.
– These stepper motors will be used for lateral motion and
guidewire advancement.
• A voltage reactive polymer will be used for precision tip
control.
Overall Block Diagram
Camera (User’s Visual
Feedback)
VGA Display (User
Input and MATLAB
Output)
Stepper Motor for tip
Pivot functionality
Keyboard Input (User)
PC Target running
MATLAB
RS-232 Serial Output
Motor Control Interface
Board
Stepper Motor for
Lateral Movement
Joystick Input (User)
Tentative
Power Electronics
Polymer Feedback
(Volts)
Polymer
Electroactive Polymer
• Material purchased from Environmental Robots,
Inc by the Mechanical Engineering department
• Responds to a DC voltage between -5V to 5V
• +-5V results in an approximate 90 degree bend
• Tip will be made of this material for precision
control
Electroactive Polymer
Characteristics
• 2 kinds of polymer available
– Platinum plated
– Gold plated
• We discussed testing procedures with the
ME’s.
– They returned voltage vs. curvature data for both
types of polymer
• Results
Platinum Polymer Positive
Deflection Angle
Voltage vs. Deflection Angle
y = 32.501x - 53.866
R2 = 0.9492
80
60
Series1
40
Linear (Series1)
20
0
1.5
2.5
3.5
Voltage
4.5
Platinum Polymer Negative
Deflection Angle
Voltage vs. Deflection Angle
y = -32.404x - 52.938
R2 = 0.9561
80
60
Series1
40
Linear (Series1)
20
0
-4.5
-3.5
-2.5
Voltage
-1.5
Gold Polymer Positive
Angle of Deflection
Voltage vs. Angle of Deflection
y = 21.139x - 32.109
R2 = 0.9888
60
50
40
Series1
30
Linear (Series1)
20
10
0
1.5
2
2.5
3
Voltage
3.5
4
4.5
Gold Polymer Negative
Angle of Deflection
Voltage vs. Angle of Deflection
y = -21.3x - 32.112
2
R = 0.9886
70
60
50
40
30
20
10
0
Series1
Linear (Series1)
-5
-4
-3
-2
Voltage
-1
0
Polymer Run Times
Platinum Plated
Run #
1
2
3
4
5
6
Time (Minutes)
4:50
4:25
4:12
3:51
3:42
3:37
Time Lasted Per Run: 04:06
Run #
1
2
3
4
5
6
Time (Minutes)
3:50
3:30
3:12
3:02
2:48
2:42
Time Lasted Per Run: 03:10
Gold Plated
Run #
1
2
3
4
5
6
Time (Minutes)
7:50
7:25
7:08
6:35
6:17
5:56
Time Lasted Per Run: 6:51
Run #
1
2
3
4
5
6
Time (Minutes)
7:38
7:32
7:19
6:52
6:36
6:06
Time Lasted Per Run: 7:00
Platinum vs. Gold
• Discussed results with ME students
– Linearity issues
– Runtime
– Current Draw
• Gold polymer was decided upon
– Runtime was the largest reason
– Slightly more linear as well
– Did not have quite as large of an angle of
deflection
Contents
• Caleb Anderson
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–
–
–
–
–
Overview of Catheterization
Project Summary
Overall Block Diagram
Electroactive Polymer
Polymer data
Platinum vs. Gold
• Derek Carlson
–
–
–
–
–
–
–
–
•
Motor Controller Board
Stepper Motors
MATLAB progress
GUI
Updated Equipment List
Updated Foreseeable Difficulties
Schedule
Collaborative Progress w/ ME’s
Questions?
Motor Controller Board
• Runs off of a USB-Serial
driver
• Dual supply mode
• 2 motors connected
draw roughly 1 amp
when running
• Controlled via MATLAB’s
serial communication
tools
Stepper Motors
• Used for rotation and advancement of
guidewire
• (2) Jameco 8.4 V motors ordered
– Suggested in Motor Controller Board
documentation
• Tested with Motor Controller board
– Full functionality achieved
– Total current draw = roughly 1 amp while
running.
Stepper Motor Specs
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Stepper Motor
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Excellent for precision control
Can be operated in forward/reverse mode
Excellent torque/size ratio
Wide variety of supply voltages
Data sheet included
Dual shaft
Check for compatible power supplies
Step angle: 0.9 degrees
No. of phases: 2
Drive System: Bipolar
Voltage(VDC): 8.4
Phase resistance (Ω): 30
Current (mA): 280
Phase Inductance (mH): 25
Detent torque(g-cm): 36
Holding Torque(g-cm): 791
Mounting hole space digonal (in.): 1.73
Mounting hole (in.) 0.15
Shaft diameter (in.): 0.155
Shaft length(in.): .29
Motor diameter (in.) 1.64
Motor height (in.) 1.20
Weight: 0.53 lbs.
Jameco P/N 163395 MOTOR,STEP,8.4VDC,30 ohm
.9deg,SHFT:.16"X.39"
www.Jameco.com
MATLAB progress
• Serial control of board completed in
command-line form
• Able to move motors independently
• Can move motors a certain distance, and then
have them return
• All commands documented in BiStep
controller board tested and functional
MATLAB GUI progress
• Documentation of MATLAB GUIde
environment
• Basic GUI designed
– Layout including buttons for advancement and
retraction of guidewire
– Command line interface for testing
– Webcam function via command buttons
• Webcam is functional separately, has not been
implemented into GUI at this point because of speed of
computer
Updated Equipment List
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(2) 1 degree stepper motors (Jameco motors)
(1) Bistep Motor Controller Board
(1) Electroactive polymer tip
(1) Surgical Guidewire
(2) DC voltage sources
(1) PC USB Webcam
(1) Logitech Wingman Pro Attack 2 Joystick
(2) Metal pulley wheels with tight rubber belts
• For gripping of the guidewire
Updated Foreseeable Difficulties
• Polymer current draw was very high on large pieces (0.5 A)
– Shielding will be a large problem inside of a human body.
– UPDATE: Shielding solutions have been discussed and
researched with the ME students.
• Polymer functionality highly dependent upon moisture
– This may be because we have worked with old and mistreated
polymer samples.
– UPDATE: New samples of polymer react better. There still is an
issue of timing though.
• Rotation and advancement of guidewire may be tricky to
perform without damaging guidewire
• UPDATE: Rubber wheel will be used to directly grip guidewire
without damage.
Updated Schedule
• Weeks 1-3
– Stepper motor MATLAB interface (Derek & Caleb)
– Webcam MATLAB interface (Caleb)
– RS-232 MATLAB interface (Derek)
• Weeks 4-6
– GUI for user input (Both)
– Develop polymer electrical characteristics (Both)
• Detailed current draw calculations
• Weeks 7-8
– Develop power electronics to actuate polymer (Derek)
– Possible polymer shielding concerns (Caleb)
• Weeks 9-10
– Stepper motor physical interface (Caleb)
– Guidewire drive system (propulsion, rotation, etc.) (Derek)
• Weeks 11-14
– Build test system (Both)
– Finalize report & Presentation(Both)
Collaborative Progress
• Meetings have been held with ME’s
– Shielding concerns have been discussed
– Medical grade wire for supply of power
– Electrically conductive adhesive for connecting
polymer to wire
– Test system construction
• New samples of polymer were ordered and
received as of last week
– These samples are for our exclusive use
Questions?