Soft Digital Logic
We developed information-processing soft machines by taking advantage of material instabilities, specifically, the buckling of membranes. Similar to a pop-up toy, a bistable membrane is able to flip when a pressure is applied. We used such membranes for the kinking of tubing, which allowed the development of a complete set of logic gates (NOT, AND, OR gates), which we assembled to functional blocks including shift registers, set-reset latches, and volatile memory. We used these functional blocks to demonstrate a soft gripper that could switch between two states (closed and open gripper), being operated from a single soft button.
- Digital Logic for Soft Devices
D.J. Preston, P. Rothemund, H.J. Jiang, M.P. Nemitz, J. Rawson, Z. Suo, G.M. Whitesides
Proceedings of the National Academy of Sciences (PNAS), 1820672116, 2019
Soft Ring Oscillator
We paid special attention to NOT gates and their assembly to ring oscillators, as they produce oscillating signals from a single, constant pressure supply. These oscillatory output pressures enable several applications including undulating and rolling motions in soft robots, size-based particle separation, pneumatic mechanotherapy (medical application), and metering fluids.
- A Soft Ring Oscillator
D.J. Preston, H.J. Jiang, V. Sanchez, P. Rothemund, J. Rawson, M.P. Nemitz, W.-K. Lee, Z. Suo, C.J. Walsh, G.M. Whitesides
Science Robotics, 4(31), 2019
Our most recent work entails a non-volatile memory device that permanently stores information. By changing the properties of the membrane, it is able to rest in the most-recently flipped state. Pneumatic signals are used to flip the membrane from one state to the other. Memory devices are important to push research towards increasingly complex robot behaviors. Much of this work draws parallels to computer engineering, whereas we just passed the point of having built the first transistor.
- Soft Non-Volatile Memory for Non-Electronic Information Storage in Soft Robots
M. P. Nemitz, C. K. Abrahamsson, L. Wille, D. J. Preston, A. A. Stokes, G. M. Whitesides
IEEE Soft Robotics Conference, New Haven, 2020