Rigid–Soft Interactive Design of a Lobster-Inspired Finger Surface for Enhanced Grasping Underwater

Abstract

Bio-inspirations from soft-bodied animals provide a rich design source for soft robots, yet limited literature explored the potential enhancement from rigid-bodied ones. This paper draws inspiration from the tooth profiles of the rigid claws of the Boston Lobster, aiming at an enhanced soft finger surface for underwater grasping using an iterative design process. The lobsters distinguish themselves from other marine animals with a pair of claws capable of dexterous object manipulation both on land and underwater. We proposed a 3-stage design iteration process that involves raw imitation, design parametric exploration, and bionic parametric exploitation on the original tooth profiles on the claws of the Boston Lobster. Eventually, 7 finger surface designs were generated and fabricated with soft silicone. We validated each design stage through many vision-based robotic grasping attempts against selected objects from the Evolved Grasping Analysis Dataset (EGAD). Over 14,000 grasp attempts were accumulated on land (71.4%) and underwater (28.6%), where we selected the optimal design through an on-land experiment and further tested its capability underwater. As a result, we observed an 18.2% improvement in grasping success rate at most from a resultant bionic finger surface design, compared with those without the surface, and a 10.4% improvement at most compared with the validation design from the previous literature. Results from this paper are relevant and consistent with the bioresearch earlier in 1911, showing the value of bionics. The results indicate the capability and competence of the optimal bionic finger surface design in an amphibious environment, which can contribute to future research in enhanced underwater grasping using soft robots.

Autoencoding a Soft Touch to Learn Grasping from On‐Land to Underwater

“…For example, visual input tends to be corrupted by background noise in an underwater environment, which could be alleviated mechanically by adding a layer of silicone skin on the finger surface. [ 43 ] We could also enhance the tactile perception using XMem [ 44 ] to track the soft finger's deformation from the in‐finger vision or use inpainting algorithms [ 45 ] to use the in‐finger vision for visual perception. The proposed underwater grasping system is yet to be tested on remotely operated vehicles in shallow and deep water for further engineering enhancement.…”

Oceanic Challenges to Technological Solutions: A Review of Autonomous Underwater Vehicle Path Technologies in Biomimicry, Control, Navigation, and Sensing

“…By replicating the propulsion and movement of jellyfish, these robots offer energy-efficient and maneuverable swimming capabilities. They find applications in marine exploration, environmental monitoring, and underwater tasks [40]. Fig.…”

Bioinspiration and Biomimetic Art in Robotic Grippers

“…These grippers feature fingers equipped with small hooks, allowing them to attach to surfaces. In another instance, a lobster-inspired gripper was introduced in [ 254 ], where the contact interface of each finger incorporated multiple sharp pins, enabling an interlocking mechanism when handling hefty objects (see Figure 10 b).…”

“… B-I grippers based on hooking and locking mechanism mimicking different animals: ( a ) beetle-leg-inspired gripper [ 250 ] (© MDPI Biomimetics Volume 8 Issue 1 ), and ( b ) lobster-jaw-inspired gripper [ 254 ] (© 2021 Frontiers ). …”