Vacuum fluidic circuits with logic control and on-site oscillation tunability for electronics-free soft robots

Abstract Fluidic circuits advance the soft pneumatic robot beyond the dependence on bulky and rigid control components. However, many existing fluidic logic architectures, which were primarily developed for positive pressure operation, exhibit limited adaptability to vacuum actuation, particularly in achieving on-site period tunability in fluidic oscillators. This paper presents vacuum fluidic circuits that leverage origami-inspired soft valves to achieve logic control and tunable oscillation for soft robotic manipulation in dynamic scenarios. The soft valve achieves airflow control via tube kinking and serves as a fundamental NOT logic gate. This design contributes to more complicated logic operations and fluidic oscillators via strategic valve arrangements. Based on the theoretical analysis, the flow regulator is introduced into fluidic circuits to enable the tunable oscillating period from 2.4 s to 15.6 s. Combined with logic input and programmable actuation, diversified robotic operations, including autonomous actuation, object sieving with multi-level periods, and omnidirectional locomotion control, demonstrates the control flexibility for versatile applications. This on-site tunability of fluidic circuit enables vacuum-driven soft robots to perform dexterous and electronics-free operations with scalability and programmability, showcasing the possibility toward mechanical intelligence.