Robust Parameter Design of an Ascender Affecting Rope Deformation for High Repeatability

In this study, an optimized traction pulley is designed to achieve high repeatability of rope winches of surface-cleaning robots that estimate positions using the lengths of the ascender and flexible rope. When a slip occurs, measuring the length of the rope becomes difficult, which further complicates position estimation and control. However, if the slip is constant and repeatable, the error can be corrected by estimating the position. Herein, traction pulley’s design parameters(Pulley diameter, Number of groove,Pressure roller force) was experimentally evaluated using Taguchi method and Full Factorial Design. Based on two experiments, the optimal design parameters of the pulley were determined to be a diameter of 205 mm, 45 grooves, and a pressure roller force of 47 N. The optimized pulley demonstrated improved performance by reducing the standard deviation in the position error by 70.1 % compared with that of the optimized pulley reported in a previous study. Thus, applying the optimized traction pulley in future studies is expected to improve the accuracy of position estimation.