An optical system for communication and sensing in millimetre-sized swarming microrobots

Microrobotic technology underlines the concept of top–down fabrication of autonomous or semi-autonomous robotic systems, with the final aim to produce autonomous micromachines. For millimetre-sized robots, all the sub-component modules must be conceived and designed as minimal components able to accomplish a specific basic task, and each of them consequently represents a fundamental part in the whole microrobotic system. Communication and sensing modules, in particular, are indispensable to the microrobot in order to physically interact with its neighbours and the surrounding environment, a fundamental feature for multi-agent or swarm robotic systems. At present, there exist no communication and sensing modules suitable to be integrated in millimetre-sized microrobots that fulfil the requirements of the application discussed in this paper. The objective of the paper is to present the development of an integrated and scalable miniaturized optical system for communication and sensing in swarming microrobots that are among the smallest ever reported. The system consists of optoelectronic devices in a die form, which are assembled on a substrate and encompassed in a mirroring polymeric structure. The final experimental results demonstrate the effectiveness of the optical module, and potential methods for further improving the system performance are finally proposed.