Highly Repeatable Rope Winch Design With Multiple Windings and Differential Gear Mechanism

Abstract

This paper presents a rope winch with high position repeatability using a differential gear mechanism. This winch is easy to apply to existing buildings using synthetic fiber ropes, which are generally used by building exterior maintenance workers, and can be widely utilized as a winch of a gondola or climbing robot. Multiple pulleys are used to achieve high payloads, and differential gear mechanisms are used to distribute the torque across each pulley evenly. Uniform torque distribution minimizes slipping on each pulley, which reduces the power loss due to friction. This is proven through an analysis using the capstan equation and an experiment on a test bench. In addition, a criterion for the position repeatability of the winch is designed, and its results show that one pressure roller achieves optimal performance when the roller at the free end is pressed to 37 N. Extensive experiments were carried out on the final model of the winch, and position repeatability of under 50 mm deviation per 10 m was achieved through stable torque distribution under various payloads. INDEX TERMS Rope winch, differential gear mechanism, position repeatability, capstan equation, rope tension modeling.

Position Error Compensation of Façade-Cleaning Robot by Optimal Rope Winch Design

“…The rope deforms owing to differences in tension within the slip zone. This, in turn, causes positioning error of the robot [15], [19].…”

“…The pressure module force is important for producing a sufficient frictional force between the synthetic fiber rope and pulley. The problem is that although this force can help exert adequate frictional forces, it can also act as a resistance force owing to the radial elasticity of the rope [15]. Therefore, the number of pressure modules and the pressure module force were selected as design parameters because these could affect the position repeatability of the rope winch owing to the rope's characteristics.…”

“…A multi-wound differential pulley winch (MWDPW) has been proposed to improve position accuracy (Fig. 1, (b)) [15]. In this system, two pulleys and a differential gear module are installed at the center.…”