Endoscopic Capsule Robots


Pill-cameras have established themselves within the past few years as the primary diagnostic tool for the small intestine. However, they have several limitations which we are addressing by creating pill-sized endoscopic capsule robots. One is the inability to actively control their position (e.g. to "back up" or aim the camera in a desired direction). Another is that their size causes them to tumble in the large intestine, returning images with little clinical utility. Furthermore, they are not yet capable of directly delivering therapy or taking biopsy samples. At Vanderbilt, we are working toward systems that can address both diagnostic and interventional capabilities for capsule robots.

To address the diagnostic issues, we have developed capsule robots in collaboration with the CRIM laboratory, SSSA, Italy, that include legs. The latest version in a series of prototypes matches the dimensions of commercial pill-cameras (11 mm diameter by 25 mm long) and is thus swallowable. It includes 12 legs, which are actuated by two motors.
      
(Left) The 12-leg capsule robot (Right) CAD image of internal robot mechanics.


The key idea of this design is a novel slot-follower mechanism driven via lead-screw. Designing robots at this "meso-scale" requires careful consideration of kinematics, statics, and dynamics of the mechanism. Designing and manufacturing individual components is also challenging; tenths and even hundredths of millimeters are significant. 



The capsule robot in ex-vivo porcine colon. The number and arrangement of legs
evenly distend the loose, elastic environment.
To address the interventional capabilities of capsule robots, we are developing novel actuators and power supply technologies, including fluid power systems. Initial progress toward these goals is summarized in our Design of Medical Devices conference abstract, listed below.



Initial fluid-powered capsule design - this capsule is designed to insufflate the intestine.

Videos:

  1. 12-Leg CAD Gait Simulation

  2. Prior 8-Leg Prototype

  3. Fluoroscopic In-Vivo 8-Leg Video

Journal Publications:

  1. P. Valdastri, R. J. Webster III, C. Quaglia, M. Quirini, A. Menciassi, and P. Dario. A New Mechanism for Meso-Scale Legged Locomotion in Compliant Tubular Environments. IEEE Transactions on Robotics, 2009. In Press. Advance copy available from IEEE Xplore: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4799108&isnumber=4359257

  2. C. Quaglia, E. Buselli, R. J. Webster III, P. Valdastri, A. Menciassi, and P. Dario. An Endoscopic Capsule Robot: A Meso-Scale Engineering Case Study, Journal of Micromechanics and  Microengineering, 2009. In Revision.

  3. J. L. Toennies and R. J. Webster III. A Wireless Insufflation System for Capsular Endoscopes. ASME Journal of Medical Devices, 2009. Accepted.

Conference Publications:

  1. M. Quirini, R. J. Webster III, A. Menciassi, and P. Dario.  Design of a Pill-Sized 12-legged Endoscopic Capsule Robot.  IEEE International Conference on Robotics and Automation, 1856-1862, 2007.

Posters:

  1. J. L. Toennies and R. J. Webster III. A Wireless Insufflation System for Capsular Endoscopes. ASME Design of Medical Devices Conference, 2009.  Best Poster Award.

Patents:

  1. M. Quirini, R. J. Webster III, A. Menciassi, and P. Dario. Teleoperated Endoscopic Capsule. International Patent application PCT/IT2007/000259.