Soft Digital Logic
We embedded physical intelligence into materials 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. Physical intelligence plays an important role in our quest to develop inexpensive air-releasable robots (ARRs). By implementing ARRs as hybrids of electronics and computational materials, we can reduce their cost while making them more resilient to harsh environments.
- 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
By having developed fundamental logic blocks, we are capable of assembling them to increasingly functional circuits including ring oscillators. Ring oscillators 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. Such circuits build the foundation for ARRs that can operate underwater and on water surfaces.
- 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
We developed memory elements that are entirely built from soft materials. By changing the properties of the membrane of the bistable valve, it is able to rest in the most-recently flipped state. Much of this work draws parallels to computer engineering, whereas we just passed the point of having built the first transistor. ARRs will benefit from increasingly capable computational materials, gaining functionality from the implementations of their physical bodies.
- 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