30 May 2017
Scalable Pneumatic and Tendon Driven Robotic Joint Inspired by Jumping Spiders; A. Spröwitz, C. Göttler, A. Sinha, C. Caer, M.U. Öztekin, K. Petersen, and M. Sitti. Accepted for ICRA 2017. Fluidic actuators allow versatile, agile, and powerful motions and are commonly applied in robotics and automation. Likewise, many biological systems use fluidic actuators implemented with tissue for a wealth of tasks and performances. Spiders for example apply a hybrid mechanism of hydraulically actuated joint extension and muscle-based joint flexion to produce movement in two of their seven leg joints. Here, we present a novel spider-inspired joint mechanism employing both pneumatics and electrically-actuated tendons capable of strong, dynamic, and rapid joint movement. The implementation of the joint is closely inspired by those seen in real spiders, with a foldable structured membrane that effectively transfers all the energy from pressure to torque as the leg unfolds. To evaluate the mechanism we derived static joint models and a simple jumping model, and conducted equivalent experimental tests with a prototype of a single jumping leg robot. Besides applications in robot locomotion, the implementation and modeling of the spider-inspired joint mechanism can be utilized to further explore dynamics and functional biomechanics in spiders. In the future, we hope to use this platform to answer questions related to the impressive jumping and locomotion performances of real arachnids, and explore what morphological traits lie behind efficient spider locomotion at different size scales. Work at Max Planck Institute for Intelligent Systems, Stuttgart, Germany. Video cut and animation by C. Göttler.