Modular microrobotics transitioning from remote to on-board electronic control

Abstract

Microrobotics has traditionally relied on macroscopic control systems to direct the behaviour of microscopic entities that are too small to act autonomously. Yet in many applications, autonomous action is essential: human intervention is often too imprecise, remote or slow to be practical. In this Review, we illuminate the field of modular microrobotics, focusing on the opportunities and obstacles in achieving on-board control and autonomy. Advances in scalable methods to integrate electronics into 3D microscopic structures have finally enabled mass production and systematic downscaling of microrobots (≤1 mm), with the convergence of information processing and material fabrication technologies making on-board electronics feasible at this size, even within complex forms with interior vessels. These developments promise to disrupt current approaches based as a whole on larger, externally controlled marionette microrobots by delivering true microrobots down to the scale of biological cells. Self-assembling autonomous microrobots equipped with high-density on-board electronics are now technologically within reach, bringing learning capabilities and the coevolution of morphology and control to modular microrobotic systems. Challenges in integrating on-board electronic control have long prevented microrobots from achieving complex autonomy at small scales, leaving applications dependent on simpler, externally controlled particles. This Review examines recent developments in scaling modular microrobots down towards cellular scales.