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. 2021 Aug 26:15:736730.
doi: 10.3389/fnins.2021.736730. eCollection 2021.

Study on Magnetic Control Systems of Micro-Robots

Youjia Shao  1   2 , Ashraf Fahmy  3   4 , Ming Li  1 , Chunxu Li  1   5 , Wencang Zhao  1 , Johann Sienz  3
Affiliations

Study on Magnetic Control Systems of Micro-Robots

Youjia Shao et al. Front Neurosci. .

Abstract

Magnetic control systems of micro-robots have recently blossomed as one of the most thrilling areas in the field of medical treatment. For the sake of learning how to apply relevant technologies in medical services, we systematically review pioneering works published in the past and divide magnetic control systems into three categories: stationary electromagnet control systems, permanent magnet control systems and mobile electromagnet control systems. Based on this, we ulteriorly analyze and illustrate their respective strengths and weaknesses. Furthermore, aiming at surmounting the instability of magnetic control system, we utilize SolidWorks2020 software to partially modify the SAMM system to make its final overall thickness attain 111 mm, which is capable to control and observe the motion of the micro-robot under the microscope system in an even better fashion. Ultimately, we emphasize the challenges and open problems that urgently need to be settled, and summarize the direction of development in this field, which plays a momentous role in the wide and safe application of magnetic control systems of micro-robots in clinic.

Keywords: electromagnet; magnetic control system; magnetic field; micro-robot; permanent magnet.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
(A) OctoMag control system has eight fixed electromagnetic coils for 5-DOF control (Kummer et al., 2010). (B) Model of electromagnetic coils configuration of OctoMag shows that the upper electromagnets have rotated 45 degrees relative to the lower electromagnets (Pourkand and Abbott, 2018). (C) Six electromagnetic coils setup with a camera for top-view vision feedback and a microscope lens on the top for controlling Mag-μBots (Diller et al., 2012) (D) Eight electromagnetic coils system to control multiple micro-robots with different structures (Diller et al., 2013) (E) Model of electromagnetic coils configuration shows that 8-electromagnetic coils are distributed diagonally (Pourkand and Abbott, 2018).
Figure 2
Figure 2
(A) External electromagnetic system has 8 electromagnetic coils distributed diagonally to control a micro robot with two pseudopods to perform magnetic walking (Li et al., 2020). (B) The process of magnetic walking of a micro-robot by alternately raising the left and right feet (Li et al., 2020) (C) Indirect pushing of non-magnetic microbeads (Li et al., 2020) (D) Octupole magnetic system provides magnetic drive in rotating field and gradient field to ISMEs (Zheng et al., 2021).
Figure 3
Figure 3
(A) MiniMag control system restricts 8 electromagnetic coils in a fixed hemisphere for the control of micro robots with a small working distance from the system (Kratochvil et al., 2014). (B) Omnimagnet control system has three nested cubic electromagnetic coils and magnetic ball inside (Petruska and Abbott, 2014). (C) Three-axis Helmholtz electromagnetic coils system with a PointGrey camera and three Maxon motor controllers are used for generating the dynamic magnetic fields (Yu et al., 2017). (D) 3D helmholtz coils system with two cameras for controlling CTM (Su et al., 2020).
Figure 4
Figure 4
(A) Seven permanent magnets proof mechanism system is used to prove that the maximum 8-DOF magnetic control can be achieved (Salmanipour and Diller, 2018). (B) Magnetic field generation prototype for 8-DOF control, consisting of four inner coils and four outer coils (Salmanipour and Diller, 2018) (C) BatMag control system has 9 electromagnetic coils for 6-DOF control (Ongaro et al., 2019).
Figure 5
Figure 5
(A) Single permanent magnet device to perform 2-DOF rotation of the external permanent magnet through the joint unit and move the external permanent magnet in the three XYZ directions through cartesian coordinate robot (Kim et al., 2008) (B) Stereotaxis Niobe magnetic control system, including two independently rotating permanent magnets (Carpi and Pappone, 2009b) (C) External permanent magnet control system in which permanent magnet is moved by a mechanical arm with 6-DOF (Ciuti et al., 2010a).
Figure 6
Figure 6
(A) Single rotating permanent magnet control system that rotates around a fixed rotation axis (Mahoney and Abbott, 2012) (B) Main configuration of magnetic ball in SAMM, 4 ball screws prevent the magnetic ball from moving and three omniwheels control the magnetic ball to rotate freely (Wright et al., 2017) (C) Prototype of SAMM system as the end-effector is mounted mounted to the tool frame of robotic (Wright et al., 2017) (D) Eight independently rotating permanent magnets control system (Ryan and Diller, 2017).
Figure 7
Figure 7
(A) A magnetic system consisting of 3 hollow-core coils that can rotate around their respective vertical axes (Véron et al., 2013a) (B) BigMag control system, including three movable and three stationary electromagnetic coils (Sikorski et al., 2017) (C) DeltaMag control system, including three symmetrically distributed moving coils (Yang et al., 2019); (D) ARMM control system in which a single cored coil is moved by a mechanical arm with 6-DOF (Sikorski et al., 2019b).
Figure 8
Figure 8
(A) Top view of upper cover; (B) Cross-section of main structure; (C) Bottom view of lower cover; (D) 3D structure of design.
See this image and copyright information in PMC

References

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