A Novel Magnetic Transmission for Powerful Miniature Surgical Robots

Untethered magnetically actuated robots present significant advantages for biomedical applications by allowing power to be delivered wirelessly to remote, miniature robots through flesh and bone. Nevertheless, generating enough usable force to interact with their environment remains a challenge: Most millimeter-size magnetic robots achieve forces of much less than 0.1 N, which limits their medical applications. Therefore, a compact, millimeter-scale transmission is needed to amplify the output force. A novel microtransmission system is presented, composed of a driving magnet suspended between two twisted string actuators. An analytical model of the transmission is formulated to predict its behavior under both fixed load and fixed displacement configurations. Experimental measurements are used to validate the predicted maximum achievable force, to quantify the transmission performance over numerous cycles, to determine the effect of different string materials, and to determine the impact of hysteresis and viscoelasticity. Finally, the transmission is integrated into a 3 mm diameter surgical gripper prototype to demonstrate its effectiveness. With only a modest 20 mT of applied magnetic field, the gripper generates 1.09 N gripping force—a factor of 35 improvement in mechanical advantage and a factor of 62 improvement in gripping force compared to a similar size gripper using direct magnetic actuation. This microtransmission for miniature magnetic robots will enable high-strength untethered robots for minimally invasive surgical applications.

[1]  David Bombara,et al.  Experimental Characterization and Modeling of the Self-Sensing Property in Compliant Twisted String Actuators , 2021, IEEE Robotics and Automation Letters.

[2]  Andrew Lim,et al.  Design and Comparison of Magnetically-Actuated Dexterous Forceps Instruments for Neuroendoscopy , 2020, IEEE Transactions on Biomedical Engineering.

[3]  Robert J. Wood,et al.  Robotic Artificial Muscles: Current Progress and Future Perspectives , 2019, IEEE Transactions on Robotics.

[4]  P. Fischer,et al.  Light‐Controlled Micromotors and Soft Microrobots , 2019, Advanced Optical Materials.

[5]  Eric Diller,et al.  Tetherless Mobile Micro-Surgical Scissors Using Magnetic Actuation , 2019, 2019 International Conference on Robotics and Automation (ICRA).

[6]  François A Lavergne,et al.  Group formation and cohesion of active particles with visual perception–dependent motility , 2019, Science.

[7]  Andrew Lim,et al.  Cable-Less, Magnetically Driven Forceps for Minimally Invasive Surgery , 2019, IEEE Robotics and Automation Letters.

[8]  Jee-Hwan Ryu,et al.  Preliminary Study of Twisted String Actuation Through a Conduit Toward Soft and Wearable Actuation , 2018, 2018 IEEE International Conference on Robotics and Automation (ICRA).

[9]  Bernhard Gleich,et al.  Remote magnetic actuation using a clinical scale system , 2018, PloS one.

[10]  Fumihito Arai,et al.  Manipulating Microrobots Using Balanced Magnetic and Buoyancy Forces , 2018, Micromachines.

[11]  Neel Doshi,et al.  The milliDelta: A high-bandwidth, high-precision, millimeter-scale Delta robot , 2018, Science Robotics.

[12]  S. Esener,et al.  Acoustic Microcannons: Toward Advanced Microballistics. , 2016, ACS nano.

[13]  Subra Suresh,et al.  Three-dimensional manipulation of single cells using surface acoustic waves , 2016, Proceedings of the National Academy of Sciences.

[14]  Claudia Baier,et al.  Fundamentals Of Machine Component Design , 2016 .

[15]  Sriram Subramanian,et al.  Holographic acoustic elements for manipulation of levitated objects , 2015, Nature Communications.

[16]  Shuxiang Guo,et al.  Characteristic Evaluation of a Shrouded Propeller Mechanism for a Magnetic Actuated Microrobot , 2015, Micromachines.

[17]  Guang-Zhong Yang,et al.  da Vinci robot-assisted keyhole neurosurgery: a cadaver study on feasibility and safety , 2014, Neurosurgical Review.

[18]  Jee-Hwan Ryu,et al.  Twisted String Actuation Systems: A Study of the Mathematical Model and a Comparison of Twisted Strings , 2014, IEEE/ASME Transactions on Mechatronics.

[19]  Guang-Zhong Yang,et al.  Forces exerted during microneurosurgery: a cadaver study , 2014, The international journal of medical robotics + computer assisted surgery : MRCAS.

[20]  Metin Sitti,et al.  Three-dimensional independent control of multiple magnetic microrobots via inter-agent forces , 2013, 2013 IEEE International Conference on Robotics and Automation.

[21]  C. Natale,et al.  Modeling and Control of the Twisted String Actuation System , 2013, IEEE/ASME Transactions on Mechatronics.

[22]  Zhenbo Li,et al.  An Omni-Directional Wall-Climbing Microrobot with Magnetic Wheels Directly Integrated with Electromagnetic Micromotors , 2012 .

[23]  Sukho Park,et al.  Enhanced locomotive and drilling microrobot using precessional and gradient magnetic field , 2011 .

[24]  Ioannis K. Kaliakatsos,et al.  Microrobots for minimally invasive medicine. , 2010, Annual review of biomedical engineering.

[25]  C. Natale,et al.  The twisted string actuation system: Modeling and control , 2010, 2010 IEEE/ASME International Conference on Advanced Intelligent Mechatronics.

[26]  Jake J. Abbott,et al.  OctoMag: An Electromagnetic System for 5-DOF Wireless Micromanipulation , 2010, IEEE Transactions on Robotics.

[27]  Sylvain Martel,et al.  Using a swarm of self-propelled natural microrobots in the form of flagellated bacteria to perform complex micro-assembly tasks , 2010, 2010 IEEE International Conference on Robotics and Automation.

[28]  John W. Suh,et al.  Thermally Actuated Omnidirectional Walking Microrobot , 2010, Journal of Microelectromechanical Systems.

[29]  Craig D. McGray,et al.  Power delivery and locomotion of untethered microactuators , 2003 .

[30]  Dorian Liepmann,et al.  Design and Fabrication of a Silicon-Based MEMS Rotary Engine , 2001, Micro-Electro-Mechanical Systems (MEMS).

[31]  I. Daniel,et al.  Determination of shear modulus of single fibers , 1999 .