Last updated: 04/20/2022 18:37

This project will be focusing on building a proof of concept prototype and then performing optimization to the prototype to obtain a valid snare robot that can be used in eye surgery.

• Students: Wenpeng Wang
• Mentor(s): David Usevitch, Mehran Armand

These are the desired snare loop shapes.

This is the picture of the current design of the Proof-of-concept.

Surgical snares are widely used in the medical field. These surgical snares have the following features:

• Perform the grabbing tasks inside the body
• It can move through difficult bends in anatomy
• It provides a cheap, light-weight, and durable solution to those above features

As mentioned in the title, this project is focusing on establishing the prototype of a surgical snare, especially for eye surgery. Eye unlike other organs in the body. The eye itself is a fragile and unrecoverable organ for most cases, which means that the snare created needs to maintain a highly accurate, safe, and reliable inside the limited operation window.

In order to operate the snare robot well for eye surgery, these 2 separate directions can be discussed here. The first one is the actuation of the robot, and the second is the physical housing of those actuators.

1. Actuation: this includes the control of 2 motors in order to bend the snare loop up and down, and the control of the linear actuator to bend the snare loop left and right (please reference the first figure for detailed shape). The last part of actuation is to implement a method for controlling those directions via buttons (this might be later changed).
2. Physical housing: this is to create and build the 3D model holding those actuators stated in the previous paragraph for each generation of the prototype. The team finished designing the proof-of-concept and started to work on the next step of modeling (the figure above is the proof-of-concept prototype).

The creation of this tool will advance the procedure in delivering medicine to the retina. The robot will be inserted into the eye on the front side of the sclera. The current idea is to cut through the choroid at the same time as cutting through the sclera. By putting fluid inside, the robot can separate the choroid and retina passively and create the space for the robot to move forward. When the robot achieves the desired location, it will leave the drug at its current location. Finally, the robot will leave the eye by the same path. This will be a nondestructive way of delivering drugs to the back of retina. The following picture is the structure of the eye for reference.

• Minimum: (Expected by 03/25/2022)
  1. Design and construct a hardware platform for proof-of-concept
  2. Test the proof-of-concept prototype in a gel ball as a replica of the eye

• Expected: (Expected by 04/15/2022)
  1. Based on the proof-of-concept, make modifications to the design of physical housing and add the linear actuator to the system
  2. Implement a control method for motor and linear actuator (could be using buttons or other reasonable media)

• Maximum: (Expected by 05/01/2022)
  1. Combine all the functions obtain from above, and use the suitable hardware to finalize the tool into a new housing that can be operated easily.

Please reference the significance of the procedure the robot will take. In this section, the way of achieving the prototype will be discussed.

1. Physical housing:

Here is a picture of iterating the design for the proof-of-concept prototype. For this prototype, a slideway is added to the backplate that enables the system to bend the loop left and right.

1. Control of actuator:

Here is a picture of controlling the motor via the EPOS studio. The actual value and the demand value are either the same or very close, which can be concluded as these hold accurate results that can be safely used in the future iteration of design.

The next level of controlling the actuators will use a team-developed python package. There are two types of control algorithms. The first one is the keyboard control, which is using WASD to control the motors and stepper motors. The other one is to use a GUI to control those components. The preferred one is the GUI. The GUI provides functions to control the EPOS motors by encoder position, in which the user can command the position of the EPOS motors by filling in the entry of the needed position. The following figure is the GUI window.

This GUI should provide all the interface needed for the follow-up functions that needed to be implemented.

The following are the updated dependencies for the stage of the expected milestone.

1. Milestone name: Proof-of-concept prototype
   • Planned Date: 03/15/2022
   • Expected Date: 03/25/2022
   • Status: Finished
2. Milestone name: Expected prototype
   • Planned Date: 04/15/2022
   • Expected Date: 04/15/2022
   • Status: Finished
3. Milestone name: Maximum prototype
   • Planned Date: 05/01/2022
   • Expected Date: 05/01/2022
   • Status: Started and changed due to introduce the stepper motors.

• Project Plan
  • cis_plan_pres.pdf
  • cis_ii_project_proposal.pdf
• Project Background Reading
  • See Bibliography below for links.
  • Background Reading Report:
  • background_reading_report.pdf
• Project Checkpoint
  • checkpoint_pre.pdf
• Paper Seminar Presentations
  • background_reading_presentation.pdf
• Project Final Presentation
  • cis2_poster.pdf
• Project Final Report
  • final_report.pdf

* here list references and reading material

Cehajic-Kapetanovic J, Singh MS, Zrenner E, MacLaren RE. Bioengineering strategies for restoring vision. Nature biomedical engineering. January 2022. doi:10.1038/s41551-021-00836-4 bioengoineering_strategies_for_restoring_vision_nat_biomed_engr_2022.pdf

Kim HM, Woo SJ. Ocular Drug Delivery to the Retina: Current Innovations and Future Perspectives. Pharmaceutics. 2021;13(1). doi:10.3390/pharmaceutics13010108 ocular_drug_delivery_to_the_retina.pdf

The documentation and the working directory are in the project OneDrive. The team is still figuring out a way to include the directory here.

The link here is the document for using the directory. how_to_use.pdf

The link here is for the project GitHub (currently private): https://github.com/dusevitch/snare_control