Design and Testing of a Magnetic Soft Crawling Robot With Multimodal Locomotion Driven by 3-D Magnetic Fields

The non-contact driving of soft robots by magnetic fields has potential for practical application. To enable motion of untethered robots in a narrow space, a magnetic soft crawling robot with multimodal locomotion was developed. Methods of calculating the magnetic field intensities generated by the Helmholtz coils and the permanent magnet under the ideal conditions were proposed and the driving systems based on the Helmholtz coils and permanent magnet were designed. A soft crawling robot with multimodal locomotion driven by the magnetic dipole fields was devised. Furthermore, three locomotive modes (inchworm-like motion, creeping, and tumbling) of the soft robot were analyzed and simulated. Finally, a highly tough hydrogel was fabricated to manufacture a prototype of the soft robot, followed by experiments involving the motion performance of the soft robot in the three locomotive modes. Simulation and experimental results show that the robot has the highest speed of 36.2 mm/s, it can climb over obstacles as high as 4 mm and can smoothly turn in a narrow bend of 90°. Therefore, the main contribution of this paper is to design a novel multi-mode magnetic-controlled soft robot system, which can increase the crawling speed by at least 1.6 times. During this period, the modeling, simulation and testing of the system are undertaken.