PneuSIC Box: Pneumatic Sequential and Independent Control Box for Scalable Demultiplexing

Abstract

Soft robots are well suited for various applications, including wearable robotics, haptic devices, and medical robotics, due to their inherent compliance. While there are many methods for actuating soft robots, pneumatic actuation remains the dominant choice because it enables large force output and a fast response time. However, actuating a robot with multiple independent pneumatic actuators requires an equal number of pressure regulators and associated electromechanical components, making the back-end control setup bulky, expensive, and unsuitable for potential untethered applications. In this work, we present PneuSIC Box, a pneumatic demultiplexer inspired by the working principle of a music box. Unlike other pneumatic demultiplexing methods that require many pneumatic and control inputs based on the number of actuators, PneuSIC Box operates with just a single pneumatic input and a motor. Furthermore, PneuSIC Box enables simultaneous control of multiple actuators and allows pneumatic memory retention in the attached actuators without any energy expenditure due to the use of soft kink valves. We discuss the working principle and design of the device, provide a finite element analysis (FEA) model to aid in the design of the kink valves, and present detailed device characterization. Finally, we demonstrate the device's applicability using an inchworm-like robot and a robotic hand with soft fingers.