New insights in synthetic fiber rope elongation and its detection for ultra lightweight tendon driven series elastic robots

Abstract

Selecting transmission components for tendon driven actuation systems can be challenging because of the variety of available solutions. Synthetic fiber ropes have great potential for these systems, but the typically provided characteristics are not always suitable to decide whether a rope should be used in the specific system or not. In this paper, a comparative evaluation of the elongation characteristic regarding different rope materials, manufacturers and temperatures is presented. Further, the influence of guiding pulleys is investigated concerning the application at ultra lightweight tendon driven series elastic robots. The knowledge gained from the performed new rope analysis supports the design process of tendon driven robots. Since tendon elongation influences the control performance and joint torque estimation of the regarded class of robots, a novel observer-based approach for tendon elongation detection is presented and evaluated, which enables to monitor wear for quality assurance and to avoid failures.