Pneumatic Comparator With Multiple Sensitivities for Electronics‐Free Soft Robots

ABSTRACT Integrating fluidic logic circuits into pneumatic soft robots provides an efficient approach to simplifying their bulky pressure control systems. However, despite the realization of simple oscillations and rudimentary proprioceptive responses, it remains challenging for electronics‐free devices to execute complex, multi‐step actions with minimal inputs in complicated tasks. Here, we present a pneumatic soft comparator with adjustable sensitivities to achieve programmable pressure threshold‐based reflexes for electronics‐free soft robots. This comparator leverages a monostable snap‐through mechanism with tunable energy barriers, thereby enabling programmable input pressures to trigger the reversible switching of tube kinking. Distinct logic functions, including fluidic oscillators and multi‐threshold pneumatic comparators, are constructed by strategically interconnecting several comparators. Consequently, the logic output can be precisely modulated by encoding command signals into the variation of the input pressure. By fusing this threshold‐based logic into fluidic systems, we demonstrate a soft gripper with switchable grasping modes, a soft robotic arm with tunable deformation, and a crawling robot with in situ adjustability. This pressure‐based architecture establishes a compact and minimalist control paradigm while enhancing functionality, offering a scalable pathway toward interactive electronics‐free soft robots.