Transient State Machine Enabled from the Colliding and Coalescence of a Swarm of Autonomously Running Liquid Metal Motors.

Internally triggered motion of an object owns important potential in diverse application areas ranging from micromachines, actuator or sensor, to self-assembly of superstructures. A new conceptual liquid metal machine style has been presented here: the transient state machine that can work as either a large size robot, partial running elements, or just divide spontaneously running swarm of tiny motors. According to need, the discrete droplet machines as quickly generated through injecting the stream of a large liquid metal machine can combine back again to the original one. Over the process, each tiny machine just keeps its running, colliding, bouncing, or adhesion states until finally assembling into a single machine. Unlike the commonly encountered rigid machines, such transient state system can be reversible in working shapes. Depending on their surface tension, the autonomously traveling droplet motors can experience bouncing and colliding before undergoing total coalescence, arrested coalescence, or total bounce. This finding would help mold unconventional robot in the sense of transient state machine that could automatically transform among different geometries such as a single or swarm, small or large size, assembling and interaction, etc. It refreshes people's basic understandings on machines, liquid metal materials, fluid mechanics, and micromotors.