During an age of technological innovation, automation has become more and more prevalent in various industries, leading to the development of robots to assist in performing tasks in a precise manner, free of human variation. Over the past decade, soft robotics has emerged as a field that aims to “soften” these robots by replacing the circuitry and rigid, metallic bodies with flexible materials in order to make interactions with humans safer, all while maintaining the functionality of the traditional robots. These soft robots are powered through pneumatics rather than electricity, with the manipulation of the empty space of air within the hollow, plastic constructs allowing for actuation of the robot. Stemming from a biomimetic approach, soft robots have proven capable of demonstrating semblances of motor skills and swimming gaits seen in other living organisms; however, the precise timing of movements still requires the reliance on electronics. As such, this study aims to develop approaches to minimizing the footprint of the electromechanical control hardware by employing pneumatic logic.

The concept of pneumatic logic entails the use of air to power logic circuits, which can be designed by arraying together normally-closed valves, formed using polydimethylsiloxane (PDMS) as a flexible membrane, in a microfluidic chip. This results in the development of pneumatic logic gates that act similarly to their electronic counterparts (e.g. AND, OR, NOT), with the key difference being that the pneumatic analog can be used to impede the flow of air rather than electricity, making them suitable for controlling soft robots. Powered by vacuum pressure in particular, this use of monolithic membrane valves in conjunction with pneumatic logic minimizes the electronic control hardware required to operate multiple soft robots independently, with error-checking capabilities present as well. This design also enables a mode of continuous soft robotic actuation without the need for any controllers, requiring only a source of vacuum pressure. Able to operate with low pressures and at the microfluidic scale, pneumatic logic presents itself as an attractive option for controlling soft robots in an efficient manner.