Macroslip detection for a metal V-belt continuously variable transmission using the period difference

Abstract

In this study, a macroslip detection method is proposed for a metal V-belt continuously variable transmission. The macroslip detection method was developed using the instantaneous periods of the primary pulley’s acceleration and the secondary pulley’s acceleration, which can be obtained from the existing speed sensors. To obtain the instantaneous periods of the accelerations of the pulleys in real time, a signal-processing method was developed on the basis of zero-cross detection. Using the instantaneous periods, the period difference is introduced, and a threshold value b is defined to evaluate the slip state. The characteristics of the period difference and b were investigated by a three-dimensional analysis, in which a three-dimensional model of the continuously variable transmission including the blocks, the bands and the pulleys was constructed, and the velocity of each element and the slip rate were obtained. From the simulation results, it was found that the period difference stays below the threshold value b in the microslip region and begins to increase over the threshold value b in the macroslip region. The macroslip detection method proposed in this study was validated by experiments, which showed that the method is effective for detecting the occurrence of macroslip, independently of the input torque and the speed ratio.