Abstract: Biomimetic micro-robot technology based on non-contact and cable-free magnetic actuation has become one of the crucial focuses of future biomedical research and micro-industrial development. Inspired by the motion characteristics of ray fish, this article proposes a micro-robot with magnetic controlled bionic ray structure. The micro-robot is made of soft elastic materials such as poly dimethyl siloxane (PDMS), Ethylene-Propylene-Diene Monomer (EPDM), and magnetic material Neodymium Iron Boron (NdFeB) nanoparticles. The external driving magnetic field is a periodic oscillating magnetic field generated by a Helmholtz coil. In order to verify the feasibility of the ray-inspired micro-robot, the motion principle was analyzed and several experiments were carried out. Experimental results demonstrated that the ray-inspired micro-robot can excellently mimic the crucial swimming characteristics of rays under the driving force of a oscillating magnetic field with an intensity of 5 mT and a frequency of 5 Hz, the swimming speed of the biomimetic micro-robot can reach nearly 2 body lengths per second. Analysis shows that the speed and stability of the micro-robot primarily depends not only on the amplitude and frequency of the vertical oscillating magnetic field, but also on the magnitude of the horizontal uniform magnetic field. This article demonstrates that the designed biomimetic micro-robot has the potential application of remotely performing specialized tasks in confined, complex environments such as microchannel-based scenarios.

Key words: Ray-inspired · Micro-robot · Magnetic field · Motion characteristics · Magnetic film