Stochastic self-reconfiguring robots are modular robots that possess the ability to autonomously change the arrangement of their modules and do so through the use of non-deterministic processes. We present a concept for a robotic system in which the stochastic behavior of turbulent flow in a chamber is used during assembly and disassembly operations. The thermorheological properties of Pluronic®are used to implement flow routing for controlling the assembly process. This is the first use of thermorheological valving in three dimensions. A novel reversible module connection mechanism using a low melting point alloy which is soldered in a fluid environment is presented. Together with our approach to self-alignment, these are the innovations required to allow scalable self-directed assembly in three dimensions.

Modular robotic systems typically assemble using deterministic processes where modules are directly placed into their target position. By contrast, stochastic modular robots take advantage of ambient environmental energy for the transportation and delivery of robot components to target locations, thus offering potential scalability. The inability to precisely predict component availability and assembly rates is a key challenge for planning in such environments. Here, we describe a computationally efficient simulator to model a modular robotic system that assembles in a stochastic fluid environment. This simulator allows us to address the challenge of planning for stochastic assembly by testing a series of potential strategies. We first calibrate the simulator using both high-fidelity computational fluid-dynamics simulations and physical experiments. We then use this simulator to study the effects of various system parameters and assembly strategies on the speed and accuracy of assembly of topologically different target structures.