Underwater Soft Peristaltic Swallowing Robot with Multimodal Perception

An underwater soft peristaltic swallowing robot with multimodal perception is presented. Moving beyond conventional pick-and-place (PnP) paradigm, we introduce a simultaneous pick-and-place (sPnP) framework that enables continuous object ingestion and transport without interrupting manipulator mobility. Fabricated as a tendon-driven, dual-segment soft continuum robot from compliant material, the proximal segment enables precise omnidirectional bending and axial extension, while the distal segment integrates eight independently controlled inward-contracting hydraulic actuators to realize rhythmic peristaltic transport. To support safe and adaptive operation in complex underwater environments, an embodied electrical impedance tomography (EIT) architecture is integrated directly into the mesh-structured body. This system simultaneously delivers real-time morphology self-perception (bending direction, bending angle, and axial length) and anomalous-object detection (internal/external conductors and insulators), achieving multimodal awareness of the robot’s own shape, external contacts, and the position of internal swallowed objects. Extensive underwater experiments demonstrate high-fidelity morphology tracking (maximum bending direction error 7.67%, maximum bending-angle error 2.6°, less than 1.1 mm axial length error), robust internal/external object localization even under bent configurations, and stable peristaltic swallowing with concurrent perception across multiple postures. These results establish a transformative paradigm for underwater soft robotics that unifies compliant manipulation, energy-efficient internal transport, and embodied multimodal perception, laying the foundation for future soft robotic systems with enhanced autonomy in unstructured marine environments.