Session: 06-05: Continuum Robotics

Paper Number: 110881

110881 - Soft Tentacles for Underwater Robotics Powered by Twisted and Coiled Artificial Muscles (Tcams) 

Traditional robotic actuators present inherent limitations to the development of soft robotics due to trade-offs between size, power, weight, and cost.  Recently developed Twisted and Coiled Artificial Muscles (TCAMs) seek to overcome these limitations and enable the development of novel soft robotic devices by utilizing inexpensive and commercially available components while exhibiting incredible performance: current iterations are able to lift up to 12,600 times their own weight with an input voltage of 0.2 V/mm. We previously used TCAMs to develop four muscular hydrostats which mimic the motion and anatomical musculature arrangement of cephalopod limbs: contraction, torsion, bending, and extension. In this work, we seek to optimize these hydrostats through the development of a theoretical models and the use of finite element simulations as well as demonstrating underwater actuation of all four devices. In order to maximize hydrostat performance, we also evaluate a range of precursor fibers materials for TCAM manufacturing in air, aquatic, and simulated marine environments. The theoretical model for torsional hydrostats takes into account the dual-mode contribution of the TCAM to the motion of the hydrostat as a whole and provides an accurate prediction of the angle of rotation achieved by the device. The extension hydrostat is evaluated via finite element modeling to determine the optimal arrangement and number of TCAMs along with the shape and size of the unit cells which transfer the muscle contraction to the device extension. The bending hydrostats are also analyzed through finite element simulations in order to optimize the geometric properties of the Voronoi-tessellated compliant “skeleton” which determines the location and degree of bending.  We also model the behavior of the compression hydrostat for future implementation with a controller.

Finally, we demonstrate the underwater capability of our soft robotic tentacles through the creation of a Rube Goldberg machine which utilizes the hydrostats to navigate a marble through a subaquatic obstacle course.  The extension, torsion, and compression hydrostats manipulate the marble through a series of elevation changes and bring it to its final resting place where the bending hydrostat turns on a spotlight.  Modeling and testing of the hydrostats brings us closer to the realization of inexpensive and easily deployable soft robotic tentacles.

Presenting Author: Sean Maxson University of Iowa

Presenting Author Biography: Sean Maxson is a graduate research assistant in the Smart Multifunctional Material Systems (SMMS) Lab at the University of Iowa where he works on twisted and coiled artificial muscles and bio-inspired soft robotics. He holds a BSE in Biomedical Engineering from the University of Iowa in Iowa City, Iowa.