Condition monitoring

About: Condition monitoring is a research topic. Over the lifetime, 13911 publications have been published within this topic receiving 201649 citations.

Complexity as a measure for machine health evaluation

Abstract: This paper presents a machine health evaluation technique using the Lempel-Ziv complexity as a numerical measure. Comparing to conventional techniques such as spectral and time-frequency analysis, the presented approach does not require a linear transfer function of the physical system to be evaluated, and is thus suited for the condition monitoring of machine systems under varying operation and loading conditions. Theoretical foundation of the technique is introduced, and its performance is investigated through experimental study of realistic vibration signals measured from a rolling bearing system. The results demonstrated that complexity provides an effective measure for machine health condition evaluation.

Real-time monitoring of video quality in IP networks

Abstract: This paper investigates the problem of assessing the quality of video transmitted over IP networks. Our goal is to develop a methodology that is both reasonably accurate and simple enough to support the large-scale deployments that the increasing use of video over IP are likely to demand. For that purpose, we focus on developing an approach that is capable of mapping network statistics, e.g., packet losses, available from simple measurements, to the quality of video sequences reconstructed by receivers. A first step in that direction is a loss-distortion model that accounts for the impact of network losses on video quality, as a function of application-specific parameters such as video codec, loss recovery technique, coded bit rate, packetization, video characteristics, etc. The model, although accurate, is poorly suited to large-scale, on-line monitoring, because of its dependency on parameters that are difficult to estimate in real-time. As a result, we introduce a ldquorelative qualityrdquo metric (rPSNR) that bypasses this problem by measuring video quality against a quality benchmark that the network is expected to provide. The approach offers a lightweight video quality monitoring solution that is suitable for large-scale deployments. We assess its feasibility and accuracy through extensive simulations and experiments.

A method for sensorless on-line vibration monitoring of induction machines

Abstract: This paper proposes a method for sensorless on-line vibration monitoring of induction machines based on the relationship between the current harmonics in the machine and their related vibration harmonics. Initially, the vibration monitoring system records two baseline measurements of current and vibration with the machine operating under normal conditions. The baseline data is then evaluated to determine the critical frequencies to monitor on-line. Once these frequencies are determined, the baseline vibration measurement is simply used to scale the current harmonic signal to an estimated vibration level. Based on theoretical analysis, simulation results, and the experimental results shown here, a linear relationship between the current harmonics and vibration level can be assumed. The results of two experiments on a three-phase 230 V, 10 HP induction motor operating under no load are discussed and show the feasibility of this method for sensorless on-line vibration monitoring.