Branch-scalable universal miniature pneumatic system with programmable positive and negative pressure for soft robots

Abstract

In soft robotics, pneumatic actuation is highly valued for its quick response, eco-friendliness, and affordability. Pneumatic systems are essential in pneumatic soft robots, as their movements depend on pressure states. However, existing pneumatic systems often face challenges such as large size, single type of pressure output, the ability to provide only a single type of air pressure, and the inability to expand air branches. These problems hinder the development of integrated and intelligent pneumatic soft robots. In this work, we designed a miniature pneumatic system to provide hardware support for the integration and intelligence of pneumatic soft robot. The miniature pneumatic system using minimal components can expand the air branches according to the robotic requirements, and each air branch can independently program the output positive and negative pressure. Based on the design concept and system configuration, special inflation and deflation strategies, along with closed-loop pressure control strategies, have been proposed to achieve precise pressure control. Subsequently, we designed and manufactured a prototype pneumatic system with three independent air supply branches. Experimental results indicate that the pneumatic system can achieve a wide pressure range from −63–102 kPa, and the speed of inflation and deflation is controllable. Finally, we demonstrated three robotic applications and designed relevant algorithms to verify the feasibility and practicality of the pneumatic system. The proposed pneumatic design can meet the pressure control requirements of various soft robots driven by both positive and negative pressure. It can serve as a universal miniature pneumatic system, which is significant for the development of untethered pneumatic soft robots.