Versatile Like a Seahorse Tail: A Bio-Inspired Programmable Continuum Robot For Conformal Grasping

Compliant grasping is an important function of continuum robots that interact with humans and/or unpredictable environments. However, the existing robots often have cross-sections that remain constant along their length. This causes the robots to exhibit poor grasping ability, especially when dealing with objects with diverse curvatures. Here, inspired by the high adaptability of seahorse tails in grasping, we proposed a cable-driven continuum robot with tapered tensegrity, capable of conformally grasping objects with various curvatures. To characterize the effects of the tapering on the robot’s kinematics, we derived a mechanical model using multi-body dynamic framework for both predicting the configuration and developing a control strategy for cables. Theoretical predictions indicate that the curvature of each unit can be regulated by altering the length of the cables, allowing the robot to conform to objects with curvatures ranging from 1.48 m-1 to 28.21 m-1. We further employed a continuum robot and tested the control strategy that can be used for grasping floating objects when the curvature of the objects is used as the input. Our robotic design, which presents an example of embedded physical intelligence, can inspire in situ characterization techniques for collecting marine debris.