Biomechanics and control of the octopus arm
Yoram Yekutieli, Hadassah Academic College and
Weizmann Institute of Science
Octopus arms are remarkable tools capable of exerting high forces as well performing precision work. Their wide motion repertoire is carried out with no rigid skeletal support and is dependent on muscular hydrostat biomechanics. We study the complex interplay of biomechanical constraints and control strategies of the octopus arm by applying a multidisciplinary approach. Behavioral techniques, neurophysiology and mathematical modeling are combined to understand the generation of motion. We develop and use novel tools for data gathering and data analysis. These include techniques for tracking and 3D reconstruction of octopus arms in motion, and dynamical simulations of the arms. In previous studies we described two movements, the reaching movement and the fetching movement, as two different strategies to simplify the task of controlling the hyper redundant arm. Recently, our kinematic studies revealed that the octopus uses both bend propagation and elongation of the arm during the reaching movement. This is interesting in view of the generalized biomechanics of the octopus arm in contrast to the specialized biomechanics of the squid tentacle. Our results are used as inspiration for the development of novel, soft robotic manipulators. These devices are designed to overcome some of the limitations of traditional rigid links robotics. Such manipulators can use their elongated bodies to bypass obstacles and manipulate objects in cluttered or unstructured environments.