A Modular Soft Robotic Wrist for Underwater Manipulation

Abstract

This article presents the development of modular soft robotic wrist joint mechanisms for delicate and precise manipulation in the harsh deep-sea environment. The wrist consists of a rotary module and bending module, which can be combined with other actuators as part of a complete manipulator system. These mechanisms are part of a suite of soft robotic actuators being developed for deep-sea manipulation via submersibles and remotely operated vehicles, and are designed to be powered hydraulically with seawater. The wrist joint mechanisms can also be activated with pneumatic pressure for terrestrial-based applications, such as automated assembly and robotic locomotion. Here we report the development and characterization of a suite of rotary and bending modules by varying fiber number and silicone hardness. Performance of the complete soft robotic wrist is demonstrated in normal atmospheric conditions using both pneumatic and hydraulic pressures for actuation and under high ambient hydrostatic pressures equivalent to those found at least 2300 m deep in the ocean. This rugged modular wrist holds the potential to be utilized at full ocean depths (>10,000 m) and is a step forward in the development of jointed underwater soft robotic arms.

An Opposite-Bending-and-Extension Soft Robotic Manipulator for Delicate Grasping in Shallow Water

“…Previous studies have shown the promising features of soft robots for the deep sea application (Calisti et al, 2011;Cianchetti et al, 2015;Galloway et al, 2016;Licht et al, 2017;Kurumaya et al, 2018;Phillips et al, 2018;Teoh et al, 2018). In this paper, we demonstrate a soft manipulator system with dexterous motions, which aims for the shallow water seafood animal grasping (sea cucumbers, echini, etc.).…”

“…Recently, increasing studies on soft robotics have focused on the underwater applications. For example, robotic octopus arms achieved underwater locomotion (Calisti et al, 2011;Cianchetti et al, 2015); soft gripper has been used for biological sampling the coral reefs (Galloway et al, 2016); the origami gripper was applied to collecting delicate midwater organisms (Teoh et al, 2018); the jamming gripping was exploited in handling in deep sea (Licht et al, 2017); a soft glove was integrated to tele-operated control the soft wrist modules for biological underwater grasping (Kurumaya et al, 2018;Phillips et al, 2018).…”

An Underwater Robotic Manipulator with Soft Bladders and Compact Depth-Independent Actuation

“…[11][12][13][14][15] In particular, the inherent adaptation and waterproofing of soft actuators are ideal for grabbing delicate and flexible objects underwater, [16][17][18] inherited from cable-driven 19 and biomimetic approaches. [20][21][22][23] Fluidic elastomer actuators also work well in underwater applications, in terms of continuum structures, 24 hybrid structures, 25 and even modular structures, 26 tested in a high pressure environment equivalent to 2300 m depth. Three-dimensional printed soft robotic manipulators have also been proven highly successful in deep-sea operations, 27,28 tested for more than 2200 m depth, 29 offering much better compactness and inherent compliance than rigid manipulators for delicate underwater sampling.…”

A Mechatronics-Embedded Pneumatic Soft Modular Robot Powered via Single Air Tube

“…Soft modules are manufactured using soft materials, such as silica gel or rubber, which have characteristics of flexibility and continuous deformation. Therefore, many researchers have studied soft modular robots, including omnidirectional soft robots [13], rotary soft module and bending soft module [14], three types of pneumatically actuated soft modules (SoBL) [15], the soft modular robot with connecting part [16], elastomeric hollow cubes with magnetic connecting mechanisms [17], bidirectional bending modules [18], pneumatic actuators with four chambers [19], multi-spherical modular soft robots [20][21][22][23], bending-type fluidic elastomer actuators [24], modular soft robots with voice coil actuators [25], soft-bodied caterpillar-like modular robots [26], and vacuum-powered soft pneumatic actuator (V-SPA) modules [27,28].…”

“…Some researchers have concentrated their attention on the structure of the soft module. Kurumaya presented the rotary soft module and bending soft module, which can be combined with other actuators as part of a complete manipulator system [14]. Lee designed three types of pneumatically actuated soft modules, which can connect with each other through a unified connecting part [15].…”