Two Degrees-of-Freedom, Fluid Power Stepper Actuator Model


Vanderbilt researchers have developed a novel technology for use of a flexible fluidic actuator in MRI-guided surgical systems. This method eliminates the need for moving the patient out of the MRI machine, onto an operating table, and back in order to perform procedures. It is a safe, sterilized, and successful method to simplify MRI-guided surgical procedures.

Addressed Need

  • Robots employing compact, non-magnetic, low-noise actuators are needed for access to the patient in the case of MRI-guided surgical systems
  • This technology can be sterilized and is intrinsically safe, unlike most conventional methods

Technology Description

This device was designed around the parameters of being intrinsically safe, free of mechanical or electrical components, sterile, and compact. A fluid agnostic stepper motor provides bidirectional linear actuation in discrete increments to a needle. The needle is grasped by a pinching mechanism that consists of two flat diaphragms. The inflation of these diaphragms grasps the needle. The inflation and deflation of toroidal bellows provide bidirectional linear displacement of the needle. A mechanical stop limits the deflation, thus limiting the amount that the needle is displaced in either direction. A linear bellows provides rotational actuation of the needle. The rotational and translational bellows work independently of one another such that the needle cannot be rotated and translated simultaneously. The bellows are sealed in order to remain sterile from contaminants that could arise during surgery.

Unique Features

  • Compact, sterilized and inherently safe device
  • Can be partnered with multiple medical imagining technologies
  • Eliminates the need of multiple patient transfers between MRI machines and separate operating tables

Intellectual Property Status

A U.S. Provisional Patent Application was filed 6/12/2014.

Additional Information

  • Publication “Design and Precision Control of an MR-Compatible Flexible Fluidic Actuator”, Comber, Proceedings of the ASME/BATH 2013 Symposium on Fluid Power & Motion Control


Fig 1.  Technology prototype in CAD

Licensing Contact

Taylor Jordan

Tech ID: