Condition Monitoring of Rope-less Elevator Braking System Based on Wavelet Denoising

Abstract

The rope-less elevator driven by Permanent Magnet Linear Synchronous Motor (PMLSM) is a new technology for high-rise buildings. In the practical operation, PMLSM inevitably encounters various kinds of turbulences which directly affect the rope-less elevator's operation. The braking system is important for rope-less elevator safe and steady operation. Usually, the ordinary inspections are not able to detect some early stage faults in the elevator braking system. Based on the analyzing of braking system common faults, the article proposes a rope-less elevator braking system monitoring scheme and presents a method that uses air gap sensor, hydraulic pressure transducer and disc spring pressure sensor in order to detect running condition of braking system. The sampling signals are inevitably influenced by noise, which degrades the accuracy and precision of an analysis. De-noising by soft-thresholding is a new signal inspection method in wavelet analysis. On the base of briefly introducing wavelet de-noising theory, a wavelet de-noising analysis method is presented. The study shows that the useful information reflecting the condition of braking system can be effectively extracted from highly noised signals by soft-thresholding de-noising method.

Modeling and Prediction of Rainfall-runoff Relationship in the Yuanjiang, Red River Basin

“…The rainfall and runoff in Yuanjiang, Red River Basin from 2001 to 2010 were obtained. In order to reflect real trend of hydrological data, the noise was eliminated by wavelet analysis [9,10,[12][13][14]. We defined Signal-tonoise ratio (often abbreviated SNR) as…”

State Monitoring and Early Fault Diagnosis of Rolling Bearing based on Wavelet Energy Entropy and LS-SVM

“…The wavelet packet method is developed from classic wavelet decomposition. For classic wavelet transform [11], signals split into detail and approximation sections. The main improvement from Wavelet Transform (WT) to Wavelet Packet Transform (WPT) is that WPT splits both approximations and details.…”

Emergency braking mechanism for an elevator using hydraulic and pneumatic actuation

“…Yamaguchi et al (1996) show a setup, where, in case of power supply interruption, the current will be induced by a secondary permanent magnet and brake force will be generated to stop the elevator in case of an emergency. Zhang et al (2013) show another setup for rope less elevators. In this setup, in case of power failure, an emergency braking mechanism which employs the use of brake discs and brake pads, will stop the elevator.…”