The 8-bit pneumatic RAM chip helps a soft robot control its movements. (Image Credit: William Grover/UC Riverside)
Soft robots still run on circuitry and various electronics to operate, which can introduce some limitations for advancements. A new innovation could help overcome that obstacle. Recently, UC Riverside engineers developed pneumatic computer memory to control soft robots.
Pneumatic logic was created before electronic computers, providing advanced controls in various products ranging from thermostats and climate control systems to early 1900s pianos. Pneumatic logic involves air moving through circuits or channels. Air pressure represents on/off or true/false, which are represented by 1 and 0 in computers, triggering or ending an electrical charge. Pneumatic soft robots need a way to memorize their positional moving parts. The team realized they could replace a soft robot’s electronic memory by developing and deploying a pneumatic logic memory instead.
Their innovation consists of microfluidic valves, which controls airflow, rather than electron transistors and circuits. These valves are always sealed against a pressure drop, even if it’s disconnected from an air supply line. This produces trapped pressure differentials that operate as memories and help control the robot’s actuators. Denser arrays of these valves enable more advanced operations while reducing the costly, bulky, and power-intensive electronics that control pneumatic robots.
The team altered the microfluidic valves to deal with larger airflow rates and developed an 8-bit RAM chip capable of controlling larger and quicker soft robots. Afterward, they integrated it into two 3D-printed rubber hands. Atmospheric pressure in a valve represents a “0”, and vacuum represents a “1”. The fingers extend when they connect to atmospheric pressure, and a vacuum causes them to contract.
The robot even managed to play a few notes, chords, and “Mary Had a Little Lamb” on a piano by using a combination of the atmospheric pressure and vacuum in the RAM chip’s channels. This system is very safe since it doesn’t produce any positive pressure, which means the memory won’t explode while it’s in use.
Overall, the technology still needs some speed and complexity improvements before being deployed for everyday use. Additionally, a robot requires soft processors and components to eliminate its reliance on electronic hardware. Even then, this technology is safe enough for delicate use on wearable devices for infants with motor impairments.
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