Meeting Abstract
The tentacles of the cephalopods (such as octopus) are usually cone-shaped and highly variable in the taper angle across species. For example, the octopus variabilis has long and slender tentacles, while the octopus ovulum possess short and brawny tentacles. Inspired by this unique morphological feature, we designed and fabricated a pneumatically actuated, cone-shaped soft robotic tentacle, thereby adding to the conventional soft robots designs whose transverse section usually maintain constant across the height. A series of cone-shaped tentacles were fabricated with a uniform height of 200 mm, but with different taper angles. Combining the parametric modeling, which allows for investigations of tentacle kinematics in a systematic manner, and the experiments of the soft robotic prototypes, we examined the effect of the taper angle on the performance of the tentacle (i.e., the bending angle, the curvature, and the force exterted by the robot) across a range of pneumatic pressures (0-300kPa). The bending kinematics show that the tentacle with a small taper angle resulted in a spiral shape with a bending curvature that are significantly greater than the tentacle with a large taper angle. In contrast, the force outputs of tentacles showed opposite responses concerning the taper angle. We further speculate that there is a performance trade-off between bending capacity and force output in regards to the taper of the tentacle. Furthermore, we implemented a prototype “OctopusGripper” with rows of flexible suction cups assembled on the soft tentacle. With the aid of the suction cups empowered by vacuum, the tentacle can wrap around and grip a variety of objects with different sizes and shapes (https://www.youtube.com/watch?v=ZPUvA98uSj8).
