Projects

Self-Steering Microcatheters

Path planning for non-linear minimization of shape error and optimization of catheter design parameters

Custom 4-DoF actuation unit with series-elastic elements and load sensing

Catheter and vessel outline tracking from bi-plane fluoroscopy

Background:

  • Mechanical thrombectomy or the endovascular retrieval of blood clots, using stent retrievers and/or aspiration catheters, has become the standard of care for patients who present with acute large vessel occlusion (LVO) strokes.

  • Widespread adoption is hindered by high skill barrier due to technical complexity of navigating tortuous vasculature with passive catheters and guidewires.

  • Actively steerable microcatheters can facilitate endovascular deployment and lower the skill barrier needed to perform this surgery.

Technical Gap:

  • Existing robotic microcatheters do not meet the size, articulation, and/or open bore requirements needed for mechanical thrombectomy.

  • Current robotic catheters do not address sensing at the scale needed for neurointervention.

Contributions:

  • Kinematic modelling and image-based calibration of an antagonistic pair 2-DoF robotic microcatheter (OD 0.88mm).

  • A path planning algorithm for non-linear minimization of shape error between the robotic catheter and a target vasculature path segmented from pre-operative CT scans.

  • Non-linear optimization of catheter design parameters to minimize the tracking error for patient-specific endovascular intervention.

  • Design and fabrication of a custom 4-DoF actuation unit with series-elastic elements and load sensing for safe catheter deployment.

  • Formulation and implementation of assistive control modes for catheter self-steering using active compliance and telemanipulation.

  • Catheter tracking from bi-plane fluoroscopy imaging, using image-segmentation and extended Kalman filtering, for close-loop catheter control.

Collaborative Robots in Confined Spaces

Multi-modal sensing disk unit (SDU) with integrated Time-of-flight sensors, Hall effect sensors, magnets embedded in a protective silicone sleeve, and custom multiplexer PCBs

Fully assembled sensing disk unit

Five SDUs integrated within the structure of a multi-backbone continuum robot

Background:

  • Collaborative manufacturing in confined spaces demands cooperation modes and levels of dexterity, sensing, and safety that exceed capabilities of existing robotic systems.

  • Goal: Enable robot situational awareness in a confined space and ensure safety of the collocated user.

Sensing Requirements:

  • Mapping of the confined space

  • Bracing for improved reach and reduced motor power

  • Path planning with contacts

  • Compliant Motion with multi-point contacts

  • Safe human-robot interactions

Contributions:

  • Design, fabrication, and calibration of multi-modal sensing disk units (SDUs) capable of proximity sensing, mapping, contact detection and localization, and force sensing.

  • Formulation and implementation of a protocol for I2C communication with 40 time-of-flight sensors and 40 hall-effect sensors, in real-time.

  • Hardware and software integration of five SDUs (80 sensors) within a continuum robot for whole-body sensing and mapping of confined spaces.

Variable Geometry Continuum Robots

Multi-backbone continuum robot with different outer diameter configurations

Angulated Scissor Linkage

Technical Gap:

Current continuum robot designs lack the ability to actively vary their diameter and optimize their performance using this additional degree of redundancy.

Contributions:

  • Novel design of a multi-backbone continuum robot (MBCR) with active diameter control using circular angulated scissor linkages as spacer disks.

  • Motion analysis of angulated scissor linkages and geometric constraints on radial expansion.

  • Instantaneous kinematics and statics analysis of MBCR with variable diameter.

  • Performance analysis of MBCR with and without variable diameter, using a redundancy resolution scheme, in a simulation study.