Multimodal soft valve enables physical responsiveness for preemptive resilience of soft robots.

Resilience is crucial for the self-preservation of biological systems: Humans recover from wounds thanks to an immune system that autonomously enacts a multistage response to promote healing. Similar passive mechanisms can enable pneumatic soft robots to overcome common faults such as bursts originating from punctures or overpressurization. Recent technological advancements, ranging from fault-tolerant controllers for robot reconfigurability to self-healing materials, have paved the way for robot resilience. However, these techniques require powerful processors and large datasets or external hardware. How to extend the operational life span of damaged soft robots with minimal computational and physical resources remains unclear. In this study, we demonstrated a multimodal pneumatic soft valve capable of passive resilient reactions, triggered by faults, to prevent or isolate damage in soft robots. In its forward operation mode, the valve, requiring a single supply pressure, isolated punctured soft inflatable elements from the rest of the soft robot in as fast as 21 milliseconds. In its reverse operation mode, the valve can passively protect robots against overpressurization caused by external disturbances, avoiding plastic deformations and bursts. Furthermore, the two modes combined enabled the creation of an endogenously controlled valve capable of autonomous burst isolation. We demonstrated the passive and quick response and the possibility of monolithic integration of the soft valve in grippers and crawling robots. The approach proposed in this study provides a distributed small-footprint alternative to controller-based resilience and is expected to help soft robots achieve uninterrupted long-lasting operation. Editor's summary: Fluidic soft robots are vulnerable to failure from overpressurization and damage that leads to sudden loss of pressurization. To give these robots more resilience and extend their lifetimes, Pontin and Damian developed a multimodal pneumatic soft valve designed to isolate damage and avoid catastrophic failure. The valve passively reacts to pressure differences triggered by faults. In the forward operating mode, the valve can detect a burst and autonomously isolate the damaged section, maintaining pressure in the other parts of the robot. In the reverse operating mode, the valve can detect overpressurization and release air to prevent irreversible damage. The valve capabilities were demonstrated in a five-finger soft gripper, a two-finger soft hand, and a soft crawler that remained operational after damage. —Melisa Yashinski [ABSTRACT FROM AUTHOR]