Michael T. Tolley, Ph.D.

Postdoctoral Associate
Sibley School of Mechanical and Aerospace Engineering

Introduction: Programmable Matter

I'm interested in the concept of programmable matter, a substance that is able to change its physical properties as directed by the user. Imagine a system that assembles a pile of regular, mass-produced components into an iPod, computer, robot, or tool with embedded sensing and computation. Objects can be assembled or repaired on-the-fly, and deconstructed to be recycled into new objects when they are no longer needed. This technology would open up new possibilities for rapid prototyping, space exploration, sustainable technology, and evolutionary design.

Our approach to programmable matter involves the assembly of components with embeded electronics by manipulating the flow of fluid through an assembly chamber. My work has involved the development of a C++ based simulator to develop control strategies capable of overcoming the stochasticity in the assembly environment (see Programmable Matter Simulation below). Additionally, I have performed experiments in which 500 by 500 by 30 micron silicon tiles are assembled automatically into pre- determined structures (see Dynamically Programmable Fluidic Assembly below).

Please check out an interview Jonas Neubert and I gave on our research in Programmable Matter to Robots Podcast .

Programmable Matter Simulation

I have written a simulator in C++ based on the Open Dynamics Engine (ODE) to model the interactions of 3D programmable matter components in a fluidic environment. Simplified fluidic forces are applied to the components in order to obtain a computationally-efficient simulation.

Simulation: Fluidic assembly and reconfiguration. This simulation demonstrates the fluidic assembly of 3D cubes into an initial C-shape and the subsequent reconfiguration of this assembly into a U-Shape. Components are attracted by opening sinks on the bottom of the chamber. Once a component is attached, it opens internal valves to direct the fluid flow and attract new components where they are needed to assemble the target structure.

Dynamically Programmable Fluidic Microassembly

A major challenge in fluidic assembly is the dynamically programmable fabrication of arbitrary geometries from basic components. Current approaches require predetermination of either the assembly machinery or the component interfaces for the specific target geometries. This research persues an alternative concept that exploits self-assembly forces locally but directs these forces globally, allowing fabrication and manipulation of target structures without tailoring the substrate or interfaces. By controlling the flow in a microfluidic chamber, components are directed to their target locations where local interactions align and bond them. Following this approach, we have so far demonstrated the experimental assembly of structures composed of two to ten components.

Please see my Videos page for videos of these experiments.

Microtile manipulation and assembly. Frames taken from video micrographs of (a) an automated microtile manipulation and (b-d) three assembly experiments. Timed valve actuation directs pressurized flow into the microfluidic chamber and out the indicated openings. Fluid flow applies hydrodynamic forces to the 500 by 500 by 30 micron silicon tiles, causing them to move and assemble. Alignment patterns and compliant latches cause adjacent tiles to self-align and bond together. The valving sequences determine the final structures.

Visual Feedback Experiments. Frames from video micrographs of the assembly of symmetrical structures composed of four to ten components. Valve switching was controlled manually with visual feedback.