Chapter 7 - Small-scale robots with programmable magnetization profiles

Abstract

Millimeter and submillimeter robots promise great potential in a variety of fields. The miniature bodies of these small-scale robots endow them with distinctive advantages in comparison with the conventional larger robots. They can access small and constrained environments and perform tasks with a high level of accuracy and delicacy. While the small bodies of these robots bring unparalleled benefits, their limited onboard space prevents them from carrying the components that are essential for conventional robots, such as power and control units. To compensate for the absence of these parts, magnetic field has been utilized in novel strategies to transfer energy and signals to these robots. Magnetic field becomes a popular choice because it (1) is easy and safe to generate, (2) is able to penetrate many substances, especially biological cells and tissues, and (3) can exert both forces and torques on subjects simultaneously. The small-scale magnetic robots can be roughly categorized as rigid- and soft-bodied. The soft-bodied robots proactively utilize their deformations in reaction to the exerted magnetic field to achieve functionalities, opening up a vast number of possibilities. Their deformations are continuous and have unlimited degrees of freedom. The magnetization profiles on these robots can be programmed to be heterogeneous with complex patterns, which enable them to have sophisticated shape-morphing behaviors. This chapter discusses the development and state-of-the-art of small-scale magnetic soft robots with programmable magnetization profiles.