Self Guided Catheter

Functional Description and Complete Block Diagram

Derek Carlson & Caleb Anderson

Dr. Dempsey & Dr Stewart

10/17/06

            In surgical operations that require the use of a catheter, multiple guidewires must be used in order to direct the catheter through the patient’s arteries.  The goal of this project is to eliminate the need for different guidewires and to add precision control to the guidewire itself.  Also, the surgeon will be able to control the guidewire from a remote location simply by viewing the patient through a camera.    Control will be implemented using a joystick interfaced with Simulink using RS-232 as an output.  This will drive the controller board that 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.  Certain specifications for this project will be provided by Dr. Andy Chiou of Proctor Hospital, though the scope of the project will greatly outreach this.

            Below is the high-level functionality block diagram:

Figure 2 – 1 High Level Block Diagram

            Figure 2—1 shows that there will be both keyboard and joystick input into the control system.  Both will input via USB or PS/2 to Simulink.  Simulink will then be used to supply the signal to the motor controller board running the two stepper motors, and the voltage to the polymer at the tip of the catheter.  Visual feedback will be implemented through the use of a webcam.  This will allow the surgeon to operate from a remote location.

At this point, it is not known whether the signal to the electroactive polymer will be PWM, DC voltage, or otherwise, but further testing will reveal this detail.  The polymer tip will act as an actuator as well as a sensor.  This sensor will provide the surgeon with feedback regarding the radius of curvature.  Also, there will be a pivotal motor that will rotate the tip so the surgeon can achieve 360 degree control of the polymer.  While Dr. Chiou has not requested a motor for advancement of the guidewire through the body, a stepper motor will be implemented for this feature.  This is above the scope of what a surgeon may require, but will allow for other possible applications of this same technology. 

            This project began as an interdisciplinary project between the Mechanical and Electrical Engineering departments, but revisions have been made in order to further expand upon the initial project idea.  All that will be required for the Mechanical Engineering Interdisciplinary portion will be movement and understanding of the polymer itself. The deliverables from the Electrical Engineering side will be well above what is necessary and required from the Mechanical Engineers and the Surgeon.    For this reason, the documentation will cover only information that is pertinent to the Electrical Engineering Senior Design Project.