Robotic Assistant
for Cardiologist
Embedded Files
Motivation
A Transesophageal Echocardiography (TEE) is an ultrasound imaging technique used to analyze the structure and function of the heart. A specialized probe in manually passed down the patient's esophagus by a cardiologists to obtain clearer, more detailed images of the heart than a traditional echocardiogram. Despite the sophistication of a TEE, it has the following drawbacks:
Time consuming (2 hrs long)
Ergonomically challenging
Limited in precision
Hazardous (x-ray radiation exposure)
Objective
To overcome these drawbacks, our project goal is to remotely operate the TEE procedure after initial manual catheter insertion.
Our strategy for achieving this goal involves developing a teleoperated robotic assistant that capable of providing remote control of all probe features
Design Solution
Watch our design solution video below that summarizes our innovative approach and key features.
System CAD Model
Our system assembly comprises 200 components and 4 sub-mechanisms, each serving a unique function. Depending on the application, we employed various manufacturing techniques, including FDM 3D printing and acrylic laser cutting. We also utilized assembly methods such as threaded heat set inserts, mechanical assembly, and interference fits.
Fabricated System
To ensure seamless integration into a hospital environment, we tested our system in a simulation room using a human mannequin. This testing validated our design solution and identified areas for improvement. Refer to the functionality section below to see our system in action, and check the future works section to learn about the improvements we highlighted.
Process Diagram
The schematic on the left offers a high-level overview of our system's intended use. It illustrates how the system integrates into the hospital environment and outlines the process for setting it up and using it to obtain heart images.
Sub-Mechanisms
Our system is comprised of 4 main sub-mechanisms which are explored below.
Tip Control
Tip Control
2 DOF sub-mechanism for controlling the catheter near the patient's mouth
Minimizes error due to catheter kink
Guides catheter into mouth
Linear Translation: 80 mm ± 2.12 mm
Rotation: 360° ± 2.15°
Support Arm
Sub-mechanism for supporting tip-control
Static aluminum base
Flexible upper tubes for fine adjustments
Knob Engagement
Knob Engagement
3 DOF sub-mechanism that controls rotation of two probe handle knobs and actuation of the multi-plane angle button
Controls catheter tip flexion
Knob Rotation: 180° ± 1°
CAM actuated multi-plane angle button
Probe Handle Housing
Probe Handle Housing
2 DOF sub-mechanism for controlling probe handle translation and axial rotation
Passive linear translation
Synchronous rotation with Tip Control: 360° ± 2.82°
Electronics and Firmware
Controller
Controller
LED Display
Hosyond IIC I2c 2004 LCD Module 20x4
Shows real-time position metrics
Radio Communication
nRF24L01 Transceiver Module
Features
LCD display showing real-time position metrics
Motor step size customization
Save and restore motor positions corresponding to favorite images
Operating range: 20 meters
Emergency stop switch to immediately terminate all movements
Removable and rechargeable Li-ion battery
Electronics
Electronics
Stepper Motors
Nema 17
Linear Actuator
Firgelli Micro Pen Actuator with Feedback
Servo Motors
FEETECH 20KG Servo Motor 7.4V
Microcontrollers
Arduino Mega 2560 Rev3 (Main)
Arduino Nano Every (Controller)
Radio Communication
nRF24L01 Transceiver Module
Firmware
Firmware
Custom built stepper and linear actuator libraries
Bi-directional radio communication between main system and controller
Objected orientated C++ and Arduino
Open-loop proportional control algorithm
Open source available on GitHub
Functionality
Our system allows cardiologists to remotely control the TEE probe with five degrees of freedom (DOF).
Linear Translation
Axial Rotation
Multi-Plane Angle Slicing
Anteflex/Retroflex
Left/Right Flex
Hardware Performance and Analysis
Theoretical and experimental translation in relation to controller input
Theoretical and experimental translation in relation to controller input
Theoretical and experimental rotation in relation to controller input
Theoretical and experimental rotation in relation to controller input
Theoretical vs experimental deflection of support arm at tip under varying loads
Theoretical vs experimental deflection of support arm at tip under varying loads
Deliverables
Summary
Impact
We hope to have demonstrated that safe, precise, and user-friendly TEE automation solutions exist, and hope our project will have a novel contributed to the growing field of medical robotics
Future Work
Make TEE probe more easily accessible
Re-design the housing to allow quick insertion and removal
Create a tool-free instillation and removal
Create a universal probe mounting system to accommodate different models of TEE probe
Find a solution for accommodating probes of varying diameter, length, and knob size
Improve reliability and robustness
Upgrade the stepper motor power supply to 24V to increase torque and prevent stalling
Install limit switches to send rotation to a know home position prior to procedure
Upgrade the nRF transceiver module to a higher-quality version capable of a more stable long-range connection
Implement more comprehensive safety measures such as an E-Stop that immediately cuts power, and integrated force sensors to prevent patient injury
Acknowledgements
Thank you to Professor Delson, our TA Jackie Chen, and our sponsor Dr. Raisinghani
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