Ultragentle manipulation of delicate structures using a soft robotic gripper

Abstract

Here, we present ultragentle soft robotic actuators capable of grasping delicate specimens of gelatinous marine life. Although state-of-the-art soft robotic manipulators have demonstrated gentle gripping of brittle animals (e.g., corals) and echinoderms (e.g., sea cucumbers) in the deep sea, they are unable to nondestructively grasp more fragile soft-bodied organisms, such as jellyfish. Through an exploration of design parameters and laboratory testing of individual actuators, we confirmed that our nanofiber-reinforced soft actuators apply sufficiently low contact pressure to ensure minimal harm to typical jellyfish species. We then built a gripping device using several actuators and evaluated its underwater grasping performance in the laboratory. By assessing the gripper’s region of acquisition and robustness to external forces, we gained insight into the necessary precision and speed with which grasping maneuvers must be performed to achieve successful collection of samples. Last, we demonstrated successful manipulation of three live jellyfish species in an aquarium setting using a hand-held prototype gripper. Overall, our ultragentle gripper demonstrates an improvement in gentle sample collection compared with existing deep-sea sampling devices. Extensions of this technology may improve a variety of in situ characterization techniques used to study the ecological and genetic features of deep-sea organisms.

Soft Actuators for Soft Robotic Applications: A Review

“…Moreover, the gripper system is shown to be stimulated using low hydraulic pressures compared with ambient (6.9-41.4 kPa) and resulting in a pull force of 0.77 N and a retraction speed of 0.050 m s À1 . [260] Galloway et al demonstrated a hydraulically stimulated soft robot for gripper application as well, as shown in Figure 17b. The grippers are monolithic structures and are coupled to a palm.…”

Hands in the Real World

“…2014; Galloway et al, 2016;Laschi, 2017;Stuart et al, 2017;Mura et al, 2018;Takeuchi et al, 2018;Sinatra et al, 2019). While the non-adaptive end-effectors are most consistently utilized, they are not as suitable for nondestructive, gentle biological and archaeological tasks.…”

“…A number of hands are deployed in the ocean, from single-DOF rigid claws, such as the Schilling Titan gripper 1 , to adaptive grippers with compliant elements or underactuation (e.g., Cianchetti et al, 2011 ; Lemburg et al, 2011 ; Bemfica et al, 2014 ; Galloway et al, 2016 ; Laschi, 2017 ; Stuart et al, 2017 ; Mura et al, 2018 ; Takeuchi et al, 2018 ; Sinatra et al, 2019 ). While the non-adaptive end-effectors are most consistently utilized, they are not as suitable for nondestructive, gentle biological and archaeological tasks.…”

For safe and compliant interaction: an outlook of soft underwater manipulators

“…designed an underwater gripper driven by pressure air featuring “ultragentle” manipulation, which is shown in Figure 4(c). 27 To decrease the contact pressure, the nanofiber was used to reinforce the soft actuator, and as a result of it, the jellyfish can be grasped by the grippers. All the above grippers using silicone elastomer for its compliance and easy manufacturability.…”

“…Fluid-driven soft underwater grippers: (a) the pneumatic gripper with PA structure 25 ; (b) the hydraulic soft grippers with PA (up) and FRA (down) structure 2 ; (c) the gripper with “ultragentle” manipulation 27 ; (d) the universal soft grippers using jamming effect 29 ; and (e) a soft hydraulic gripper using hydrogel as the body material. 28 …”