Smart Surgical Tool with Haptic Feedback

The target of this project is to come up with a handheld surgical tool adapting a tactile feedback system. The tool consists of a 3-degree-of-freedom (DOF) hall effect sensor and three tactile displays. The sensor is easily embedded in the tool by adopting Hall Effect transduction principle. The sen

Project Title

Smart Surgical Tool with Haptic Feedback

Project Area of Specialization

Mechatronics Engineering

Project Summary

The target of this project is to come up with a handheld surgical tool adapting a tactile feedback system. The tool consists of a 3-degree-of-freedom (DOF) hall effect sensor and three tactile displays. The sensor is easily embedded in the tool by adopting Hall Effect transduction principle. The sensor measures the direction and magnitude of the 3-DOF force applied to the tool tip. The fingertip grasping the tool is stimulated by the tactile display to transmit the contact force information measured by the sensor. The tactile display is actuated by employing an ERM vibration motor. In this work, a prototype of the tool is designed and fabricated. Its performance is experimentally validated. The surgical tool will be equipped to differentiate between different tactile surfaces as well as the hardness of a surface or object and provide haptic feedback to the operator.

Project Objectives

1. Select appropriate sensors and medical instruments.

2. Perform FEM analysis of surgical tool for most efficient placement of sensor for integration.

3. Mathematical models of concerned mechanisms.

4. Sensor Calibration for accurate feedback.

5. Development of feedback system for accurate force representation.

6. Algorithms for signal processing from sensor to feedback system via actuator.

7. Functional Smart tool.

Project Implementation Method

The first phase of our project was the literature review to find out all the work that has been done on haptics before. We looked into the design and implementations of the work that had been done previously. After exploring all possible designs, we went with our own design by first making the hinge mechanism for transmitting force to the sensor. The hinge designs were tested on ANSYS by giving various material properties as well as different dimensions to the hinges for adequate force transmittance. Some of the design tests were made by 3-D printing the mechanism and testing it along with the sensor. Due to unavailability of a sensor suitable to our needs, we decided to fabricate our own sensor based on this design (insert citation). The sensor works on the HALL affect mechanism. It is made using four SS39ET SMD hall sensors on a double layered PCB. There is a 10mm layer of soft elastomer on the PCB with four grooves for embedding the magnets. The magnets are 2x4mm in dimensions. On top of the soft elastomer there is a layer of a hard elastomer as well. This hard sheet of elastomer allows the uniform displacement of magnets corresponding to the applied force. The sensor was calibrated and tested using LabView as well as on Arduino IDE for the interfacing. The hinge was designed based on the force to displacement values of the sensor. It transmits the normal as well as the shear force on to the sensor. The initial plan was to use DEA (Dielectric Elastomers Actuators), but due to the unavailability of the materials and the means to produce it, ERM Vibration motors were chosen to provide the haptic feedback due to their small size and the wide range of frequency. The motors are used along with a motor driver DRV2605. The motor driver comes with over 100 libraries to provide various haptic gestures and intensities. The feedback is in the form of various vibration patterns for different sense of touch. To implement algorithms for signal processing from sensor to feedback system via actuator, Arduino nano is used. It has been selected due its small form factor which gives convenience in adjusting in the tool and fast processing power. An adequate alternative is STM Bluepill 38. The body of the device 3D printed and is made to size to all of the elements that are housed within it and it comes with a snug placement of the components to help give it its compact look. One of the main focus of this design is to make it as compact as possible because of its ease of use and implementation in the robotic eye surgery, a compact and slender design is preferred.

Benefits of the Project

The Haptic Feedback SmartPen is designed for advantages in modern surgery. The product was initially designed for telemanipulation based robotic surgery such as minimally invasive surgery or eye surgery where we are deprived of the touch sensation that would be received through manual methods. Hence this product provides us with haptic feedback, allowing us to differentiate between the hardness and softness of the surface manipulated by our respective surgical tool, giving the surgeon an idea of what they are interacting with. This tool can also be used for training of surgeons, allowing them to feel which tissue/organ they are interacting with through the feedback received from this tool.

Technical Details of Final Deliverable

The force transmitting mechanism consists of hinges which transfers the force acting on the needle attached at the front to the surface of the sensor. The sensor working on the Hall Effect Principle consists of four hall effect ICs with corresponding magnets whose deflection produces a change in voltage from the given threshold value. The change in voltage drop gives magnitude whereas the IC giving the change indicates direction. This signal is sent to the microcontroller housed in the pen, which in this case is the Arduino Nano. The Arduino uses an algorithm using defined ranges to indicate which motor needs to be turned on to give an accurate depiction of direction of the force acting at the tip. Once the direction is defined the microcontroller turns the motor on according to the magnitude of the voltage from the sensor. The magnitude is determined by mapping the values of the voltage onto the PWM signals being given by the controller to the motors. The tactile display is actuated by employing ERM vibration motors. Their magnitude can be varied by either varying voltage or the PWM; for this application we have chosen PWM.

Final Deliverable of the Project

Hardware System

Core Industry

Medical

Other Industries

Core Technology

Others

Other Technologies

Sustainable Development Goals

Good Health and Well-Being for People, Industry, Innovation and Infrastructure, Partnerships to achieve the Goal

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com