Transcript Catheter Guidewire Control System

Catheter Guidewire Control
System
Derek Carlson & Caleb Anderson
Advisors: Dr. Dempsey & Dr. Stewart
Contents
•
•
•
Caleb Anderson
– Overview of Catheterization
– Project Summary
– Overall Block Diagram
– Electroactive Polymer
– Polymer data
– Platinum vs. Gold
– Microcontroller Development board
Derek Carlson
– Amplifier Circuit
– Motor Controller Board
– Stepper Motors
– MATLAB progress
– Final Equipment List
– Schedule
– Collaborative Progress w/ ME’s
– Conclusions
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 is implemented using a joystick interfaced with
Matlab.
• A purchased controller board runs 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
80535
Microcontroller
Development Kit
Power Electronics
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
Gold Polymer
Voltage vs. Deflection Angle
Voltage vs. Angle of Deflection
y = 5.6312x2 - 8.8412x + 4.0684
R² = 0.9858
80
y = 5.5005x2 + 7.4805x + 2.0405
R² = 0.9893
80
Deflection Angle
Deflection Angle
70
70
60
60
50
50
40
40
30
30
20
20
10
10
0
1.5
2
2.5
3
3.5
4
4.5
0
-4.5
Voltage
-3.5
Voltage
-2.5
-1.5
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
Polymer Characteristic Problems
• Polymer behavior is not uniform
– Polymer to polymer
– Multiple runs – same polymer
• Voltage response – highly nonlinear
– Earlier results?
– DC voltage only test signal of value
• Other test signals?
80535 Microcontroller
Development Board
• D/A used to create 0 to 5 volt test signal
• 2 methods of input
– Keypad
– Joystick
• 0-100 % Entry
• LCD Readout
Contents
•
•
•
Caleb Anderson
– Overview of Catheterization
– Project Summary
– Overall Block Diagram
– Electroactive Polymer
– Polymer data
– Platinum vs. Gold
– Microcontroller Development board
Derek Carlson
– Amplifier Circuit
– Motor Controller Board
– Stepper Motors
– MATLAB progress
– Final Equipment List
– Schedule
– Collaborative Progress w/ ME’s
– Conclusions
Questions?
Amplifier Circuit
• Frequency Response
20 Hz – 20 kHz
• Minimum Gain of 10
for no oscillation
•Non-inverting so
unity at DC
•Mute needs 0.5 mA
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
80535
Microcontroller
Development Kit
Power Electronics
Polymer
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.
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
• 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
Final Equipment List
•
•
•
•
•
(2) 1 degree stepper motors
(1) Bistep Motor Controller Board
(1) Electroactive polymer tip
(1) Surgical Guidewire
(3) DC voltage sources – (2) for motor control (1)
for op-amp.
• (1) PC USB Webcam
• (1) Logitech Wingman Pro Attack 2 Joystick
• TBA – mechanical system to test guidewire
Completion of 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
• Several meeting 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
• ME’s focused on prototype guidewire
– Our focus was on control system
Conclusions
• Electroactive polymers very promising for use
in the medical field
• Gold plated polymer used for guidewire tip
control is not developed enough for use
– Material is unpredictable and inconsistent
• Further research and development necessary
to generate more useful polymer
– Other polymers may exist that would respond
better
Questions?