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Design and evaluation of a control system for a variable stiffness catheter for eye surgery
The student will design a control system for a variable stiffness catheter. The catheter is infused with a Low Melting Point Alloy, which needs to be temperature controlled in order to control the stiffness. Feedback for the controlled is provided via the resistance change in the alloy.
Keywords: Control, medical robotics, variable stiffness, catheter, mechanical design, LMPA
The design catheters in medical robotics is of interest in numerous medical applications. The variable stiffness feature is of interest in this context because we want to be able to easily control the catheter orientation in a soft state, and apply forces for puncture, injection or grasping gesture in a stiff state.
Several technologies have already been considered for variable stiffness catheters and endoscopes in cardiac and gastric surgeries, but the small dimensions of the tools dedicated to eye surgery (where the diameter of the tools do not exceed 1 mm) makes such design particularly challenging and interesting. Expected outcomes for such a development have potential in several procedures such as eye floaters removal, membrane peeling or sub-retinal injections.
A novel variable stiffness technology has recently been investigated in the MSRL team (The Multiscale robotics lab, ETHZ) and consists in Low Melting Point Alloy (LMPA) that can be switched from a soft liquid state to a stiff solid state through temperature change around its melting point (40-50°C). The adaptation to eye surgery has however not been investigated so far and is context of this new project.
In this project, the student designs a controller for a variable stiffness catheter, which utilizes the LMPA technology. The controller should successfully sense and regulate the temperature of the catheter in order to be able to quickly switch from a flexible to solid state. The mobility and performance of the catheter will be evaluated in an eye phantom. This project is particularly interesting as the student works in robotics and mechatronics as well as simulation.
The student will take benefit from the unique equipment located in the MSRL, as well as the multi-disciplinary skills of the team members
The design catheters in medical robotics is of interest in numerous medical applications. The variable stiffness feature is of interest in this context because we want to be able to easily control the catheter orientation in a soft state, and apply forces for puncture, injection or grasping gesture in a stiff state. Several technologies have already been considered for variable stiffness catheters and endoscopes in cardiac and gastric surgeries, but the small dimensions of the tools dedicated to eye surgery (where the diameter of the tools do not exceed 1 mm) makes such design particularly challenging and interesting. Expected outcomes for such a development have potential in several procedures such as eye floaters removal, membrane peeling or sub-retinal injections. A novel variable stiffness technology has recently been investigated in the MSRL team (The Multiscale robotics lab, ETHZ) and consists in Low Melting Point Alloy (LMPA) that can be switched from a soft liquid state to a stiff solid state through temperature change around its melting point (40-50°C). The adaptation to eye surgery has however not been investigated so far and is context of this new project.
In this project, the student designs a controller for a variable stiffness catheter, which utilizes the LMPA technology. The controller should successfully sense and regulate the temperature of the catheter in order to be able to quickly switch from a flexible to solid state. The mobility and performance of the catheter will be evaluated in an eye phantom. This project is particularly interesting as the student works in robotics and mechatronics as well as simulation. The student will take benefit from the unique equipment located in the MSRL, as well as the multi-disciplinary skills of the team members
-Thermal modeling of the catheter Fabrication of the prototype
-Design of control system to regulate temperature of the LMPA
-Characterization and evaluation of the catheter stiffness variation and response time
-Evaluation of catheter mobility
-Thermal modeling of the catheter Fabrication of the prototype -Design of control system to regulate temperature of the LMPA -Characterization and evaluation of the catheter stiffness variation and response time -Evaluation of catheter mobility