Applications: Twisted String Actuation-based Compact Automatic Transmission

Abstract

Input-output transmission ratio shifting mechanisms provide a variable transmission ratio, which effectively expands a speed-force operating range of actuators. Although it is the most effective solution to increase the performance of robotic systems, its application to compact robotic systems still remains a challenging issue due to its complexity and massive structure. In this paper, we introduce a twisted string actuation-based transmission module for compact robotic systems. The twisted string mechanism provides a simplified transmission design and a compact form factor of the transmission module. An automatic transmission shifting algorithm is proposed for effective and autonomous control strategies. The developed prototype is integrated into a robotic gripper/hand, and its performance is verified with grasping demonstrations.