OctoMag: An electromagnetic system for 5-DOF wireless micromanipulation

Abstract

Abstract-We demonstrate five-degree-of-freedom (5-DOF) wireless magnetic control of a fully untethered microrobot with a magnetic steering system we call OctoMag. Although only occupying a single hemisphere, this system is capable of isotropically applying forces on the order of 1-40 µN with unrestricted control of the 2 orienting DOF. These capabilities are enabled through the use of soft-magnetic-cores which provide an increase of approximately 20× that of air cores in magnetic-field strength, but comes at the cost of more complicated interactions between coils. We propose a modeling mechanism that assumes the field contributions of the individual currents superimpose linearly when using cores with large linear regions and negligible hysteresis. When designing the system, the locations and quantity of electromagnets were optimized with regards to the force generation in the worstcase direction predicted by the model. The resultant system is capable of both open and closed-loop operation over a workspace of 4 cm 3 . OctoMag was primarily designed for the control of intraocular microrobots for delicate retinal procedures, but also has potential uses in other medical applications or micromanipulation under an optical microscope.

OctoMag: An Electromagnetic System for 5-DOF Wireless Micromanipulation

“…9-12 show a few trajectories of the device, where automated pose control refers to closed-loop position control with open-loop orientation control. The system exhibits similar performance in a wide array of different trajectories as well as for a variety of robot orientations, as illustrated in [42].…”

A discrete-time localization method for capsule endoscopy based on on-board magnetic sensing

“…Accordingly, many research groups are working to develop active locomotion devices and platforms [2][3][4]. A promising approach for active locomotion is to magnetically control endoscopic capsules by means of external magnetic fields, thus overcoming powering issues [5][6][7][8][9][10][11][12][13].…”

Cell‐Based Micro/Nano‐Robots for Biomedical Applications: A Review

“…[106] Nelson et al set an Octomag eight-coil magnetron system to drive microrobots in the lens of the animal eyes. [107] The control method of this system and related robot design provided strategies for micro-robotic ophthalmic surgery. The characteristic of rotating magnetic fields is that the vector direction of the magnetic field rotates periodically around a certain axis.…”