Stimuli-responsive electrofluidic nervous system for autonomous soft robots

Many organisms like earthworms with soft bodies and simple nervous systems can sense and respond to stimuli, conducting complex tasks such as navigation, foraging and transporting objects. However, most soft robots currently require rigid semiconductor-based electronics for sensing and control, limiting the benefits of their soft bodies and posing challenges for integration. To address these limitations, we propose a stimuli-responsive electrofluidic nervous system (SENS) composed of soft materials to realize signal generation, multimodal stimuli-sensing and decision making for multi-actuator soft electroactive robots. SENS is composed of multiple fluidic switches, which are driven by electroactive actuators and by external stimuli such as force and heat transduced into fluidic movement by sensing receptors. Electrofluidic circuits are created using these switches to achieve self-starting oscillating circuits that control input voltages to actuators and mode-selection units that activate specific oscillating circuits based on applied external stimuli to achieve stimuli-responsive behaviors. Utilizing SENS,we realized a soft crawling robot that can change its direction of motion in response to tactile and heat stimuli. The robot is made of a dielectric elastomer actuator and two electroadhesion actuators. Furthermore, an untethered soft robot has been developed with a miniaturized SENS and an onboard constant voltage power source, which can exhibit unidirectional motion. This work constitutes a step towards developing electronics-free, entirely soft autonomous robots capable of versatile and adaptive tasks.<p></p>