An Integrated Leg-Arm Underwater Robot Capable of Sensorized Grasping

Aiming at underwater operation, such as grasping and transportation, this paper proposed an integrated leg-arm underwater robot capable of sensorized grasping. The robot is equipped with four leg-arm with 3 Degrees of Freedom(DoF), and each leg-arm structure includes three joints driven by servos, a water-jet thruster with a flexible gripper, and two pressure sensors. Four leg-arm structure with water-jet thruster enable the robot move with a vectored propulsion function. This configuration of pressure sensors enables the robot to detect forces exerted on or by the flexible gripper, providing sensitive and accurate tactile and grasping feedback. Grasping is achieved by controlling servos to induce inward folding of the robotic arms, while the gripper's flexibility allows for continued adjustment of the vectored propulsion's thrust direction after target capture, preserving the robot's underwater mobility. Grasping target detection, localization and grasping experiments were conducted, and experimental results demonstrate the rationality of the grasping mechanism design, and validate the flexibility and effectiveness of the grasping approach, confirm the sensitivity of the feedback system, and verify the accuracy of target localization, thereby serving as a foundation for future underwater grasping experiments.