A Passive Spherical Chain Mechanism for Hydraulically Driven
MRI-compatible Puncture Robot
Abstract
Magnetic resonance imaging (MRI) has significantly improved the
monitoring of tumor ablation by providing high-contrast soft tissue
images. However, MRI-guided surgical procedures often involve extremely
delicate and complex manipulations, requiring an MRI-compatible robotic
system to enhance precision and reduce human error from jitter during
prolonged high-precision tasks. This article introduces a novel
MRI-compatible, hydraulically actuated needle insertion robot for
minimally invasive stereotactic neurosurgery. The robot operates based
on the principles of spherical chain mechanisms and communicating
vessels, being driven by a linear piston and actuator. A double-layer
spherical chain mechanism translates the linear motion of the piston
into rotational motion. An MRI-compatible linear encoder is constructed
using a grating ruler and optical fiber to ensure precise control. Model
predictive control (MPC) enabled the robot to track a given trajectory
accurately, allowing for precise braking pressure management and fast
response times. Testing and analysis revealed that the robotic system
achieves an average positional accuracy of 1.435 mm, with angle
accuracies of 0.401°. Additionally, the precision and repeatability of
the robot fall within the ideal range. The results demonstrate that the
developed puncture robot is both materially and structurally compatible
with the MRI environment, showcasing effective spatial positioning and
trajectory planning capabilities.