Haptic Feedback for Robotic Catheter

Mechanical Design:

System Architecture

The mechanism uses a gear-based force-feedback layout to translate user input into controlled mechanical resistance. The design prioritizes compact packaging, smooth torque transfer, and repeatable motion while maintaining accessibility for rapid iteration.

The various prototypes in different angles and PLA filament colors are displayed to the right.

Key mechanical considerations included:

• Helical gear geometry for smoother engagement and reduced backlash

• Shaft and bearing alignment to minimize friction and wear

• Modular housing to enable rapid component swaps during testing

Key Components:

• 3D-printed helical gears for controlled force transmission

• Press-fit and supported shaft assemblies with radial bearings

• Modular housing designed for tolerance iteration

• Interfaces designed for future sensor and actuator integration

Manufacturing & Prototyping:

Prototypes were fabricated using FDM 3D printing to enable rapid iteration on geometry, tolerances, and assembly fit. Multiple print revisions were used to resolve interference issues, refine bearing seats, and improve gear meshing quality.

Processes included:

• Iterative CAD updates to address tolerance stack-ups

• Post-processing and fit adjustments for rotating interfaces

• Assembly validation through repeated disassembly and rebuilds

Soft Sensor Integration & Fabrication

Additional Processes included:

• Design of sensor mounting features compatible with flexible materials

• Iterative positioning to balance sensitivity and mechanical robustness

• Integration of the sensor with printed components without constraining motion

Testing & Iteration:

Testing focused on mechanical performance, stability, and usability under repeated actuation, evaluating smoothness, force consistency, and alignment stability across operating cycles. An Arduino Uno R4 Minima was used for motor control and monitoring via a DRV8833 driver, with angular position feedback from an AS5600 magnetic encoder and load estimation from an INA169 current sensor.

Key testing steps included:

• Manual and motor-driven actuation testing

• Identification and correction of gear interference and shaft misalignment

• Evaluation of force and current consistency across repeated cycles

• Validation of encoder feedback and control responsiveness

Design iterations were informed by observed mechanical failure modes, sensor feedback, and user interaction during testing.