Large deformation analysis of the magneto-responsive beam and its applications in flexible grippers and robots

Due to their superior biocompatibility, flexibility and control strategy compared to the traditional robots, soft robots have been widely used in a wide spectrum of engineering areas, such as biomedical, exploration, aerospace, intelligent devices and other fields. However, the existing soft robot structures mainly focus on employing homogeneous materials, which greatly limits the design flexibilities of soft robots, and correspondingly, the existing theories are usually invalid for calculating heterogeneous large deformation beam models. Therefore, we developed a novel simulation method and an advanced theoretical calculation method for representing the large deformation of both the homogeneous and heterogeneous beams made of magneto-responsive materials prepared by mixing silicon rubber with NdFeB particles. We found the experimental and numerical results agree very well, showing that the heterogeneous beam can demonstrate a better driving performance than the homogeneous beam. Optimal parameters are afterwards obtained based on the developed simulation and theorical methods. Next, we generalize the optimized heterogeneous structure to engineer the flexible gripper and the soft robot. The grasping forces of the gripper are calculated based on the variational model of large deformation beams, which are consistent with the simulation and experimental values. Moreover, the motion mechanism of magnetic soft robot has been revealed through comprehensive force analysis and formulaic rigid body motion analysis. These findings have strengthened our understandings on the deformation of slender structures and the locomotion of magnetic soft robot, which are promising to guide the design and analysis of innovative devices and robots.