The Ocean One hands: An adaptive design for robust marine manipulation

Abstract

Underactuated, compliant, tendon-driven robotic hands are suited for deep-sea exploration. The robust Ocean One hand design utilizes elastic finger joints and a spring transmission to achieve a variety of pinch and wrap grasps. Compliance in the fingers and transmission determines the degree of load-sharing among contacts and the hands' ability to secure irregularly shaped objects. However, it can also decrease external grasp stiffness and acquisition reliability. SimGrasp, a flexible dynamic hand simulator, enables parametric studies of the hand for acquisition and pull-out tests with varying transmission spring rates. In the present application, we take advantage of achieving different stiffnesses by reversing the direction of tendon windup using a torsional spring-loaded winch. With this provision, the hand can be relatively soft for handling delicate objects and stiff for tasks requiring strength. Two hands were field-tested as part of the Ocean One humanoid platform, which acquired a vase from the La Lune shipwreck site at a 91 m depth in the Mediterranean Sea.

Hands in the Real World

“…Various efforts have sought to develop adaptive and reconfigurable hands for these environments, such as in works by Lovchik and Diftler (1999), Laliberté and Gosselin (2001), and FIGURE 1 | Examples of real world applied hands (Lovchik and Diftler, 1999;Hemming et al, 2014;Controzzi et al, 2016;Galloway et al, 2016;Gardecki and Podpora, 2017;Stuart et al, 2017;Friedl et al, 2018;Negrello et al, 2018). This paper focuses on field exploration, industrial applications, service robots, search and rescue and prosthetics.…”

“…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.…”

SUAS: A Novel Soft Underwater Artificial Skin with Capacitive Transducers and Hyperelastic Membrane

“…In Eq. (11), N is a positive integer which determines the number of terms in the strain-energy function, μ p are (constant) shear moduli and α p are dimensionless constants, p = 1, . .…”

Ocean One: A Robotic Avatar for Oceanic Discovery

“…However, when lifting heavy artifacts or extracting an object from sediment, a high transmission stiffness is useful. In Ocean One's design, the degree of load sharing between fingers can be determined by selecting between two transmission stiffnesses based on actuation direction [20]. The geometry of the hands is constrained by the need to achieve a variety of common grasps, including wrapping on heavy frames or tools and more delicate pinching [5], [7].…”