Basic study for drive mechanism with synthetic fiber rope – investigation of strength reduction by bending and terminal fixation method

Abstract

In this study, we investigate physical properties of synthetic fiber ropes for drive mechanism. First, we carry out experiment about the relation between tensile strength and bending ratio D/d, where D is pulley diameter and d is rope diameter. Although it is widely known that a metal wire rope gets strength reduction under small D/d, we newly detected that a synthetic fiber rope also gets strength reduction in the same way. Secondly, we evaluate the strength of various end fixation method of synthetic fiber rope. Knot fixation make rope strength half in all kinds of knot. Clamping fixation with enough pressuring force can get large strength even if a synthetic fiber rope has low friction coefficient. Although calking fixation and sewing fixation cannot change rope length easily, they can get the largest strength around 85 to 90 % of the rope strength in our experiment.

Development of New Terminal Fixation Method for Synthetic Fiber Ropes

“…In our previous work, we experimentally evaluated several terminal fixation methods with an adjustable length function. However, the maximum strength efficiency still remained at 83.7% [13], which is not so high when compared to the steel wire rope fixation.…”

Super Dragon: A 10-m-Long-Coupled Tendon-Driven Articulated Manipulator

“…10. A 30 mm reel diameter is selected, which achieves a maximum tension greater than 90 % of the tensile strength, based on our previous work to investigate the strength decrease caused by pulley bending [15]. The arrangement of the DC actuators was optimized to minimize the size of the base structure while keeping the JCTs pathways clear and the maintenance easy.…”

“…We selected a 2 mm-diameter Dyneema rope (tensile strength of 4.29 kN, DB-96HSL, Hayami industry) as the JCTs because of these characteristics. We intensively investigated the basic mechanical properties of various types of synthetic fiber ropes in our previous work [15] [16] [17], and found that Dyneema had the highest durability against sharp repetitive bending.…”

Bundled Wire Drive: Proposal and Feasibility Study of a Novel Tendon-Driven Mechanism Using Synthetic Fiber Ropes

“…The upper arm is rotationally driven around the vertical axis by a timing belt. The curvature of the joint sliding surface is set to R = 20 mm so as not to cause strength reductions in the ropes by bending [4]. The material of the sliding surfaces in contact with the rope is made of POM, and UHMWPE fiber rope (Hayami Industry Co., DB-96HSL, diameter 2 mm) was used.…”

“…Thus, if we were to fully exploit these advantages of synthetic fiber ropes, it may be possible to develop a high performance robot, which is not feasible with conventional mechanisms. In our previous works, we investigated modeling of synthetic fiber ropes [3], tensile strength degradation by bending [4], repetitive bending durability [5], and the terminal fixation method [6].…”