Overview
A master-slave robot manipulator has been developed for needle-based teleoperation within an MRI chamber, specifically targeting abdominal interventions. The system is designed to be MR-safe and facilitates real-time MRI-guided procedures. It integrates a human-operated master controller with a slave manipulator through fluid transmission, complemented by a digital master controller for multimodal operational capabilities.
Approach
The system architecture comprises a 2+1-DoF (degrees-of-freedom) master controller manipulator that transmits motion and force to a corresponding 2+1-DoF slave manipulator. This transmission is achieved via a fluid-based mechanism. A digital master controller is incorporated to provide control capabilities beyond those typically found in split-axis or mode-switchable hybrid human-digital controller configurations detailed in prior studies.
For remote angulation control, high input impedance, low-leakage, elastomeric fluid actuators are employed. For remote actuation of the needle insertion axis, low-friction graphite piston cylinders are utilized. This choice for the needle insertion axis is based on the system's ability to provide sub-newton force transparency and sub-millimeter motion transmission over bedside fluid piping lengths.
The manipulator supports various control modes, including manual, digital, hybrid, and collaborative. Collaborative tasks demonstrated include assisted tissue penetration, fault-driven virtual fixture, and motion compensation via feedback control.
Findings
Preliminary MR scanner results were obtained from an in-vivo pig experiment. These results demonstrated the functional viability of the manipulator in a bedside, manual control mode configuration.
Why This Matters
The system enables real-time MRI-guided interventions by providing a MR-safe teleoperation platform. This approach integrates manual, digital, hybrid, and collaborative control modes, offering flexibility for complex procedures.
Key Limitations Mentioned by Researchers
The provided information details a preliminary experiment in a specific configuration (bedside, manual control mode) with an in-vivo pig. The extent of testing across all described control modes (digital, hybrid, collaborative) and other potential applications is not elaborated upon in this abstract.