Research on measuring device and quantifiable risk assessment method based on FMEA of escalator brake

Abstract

To improve the accuracy of braking distance measurement and reduce the impact of human factors on brake risk assessment of escalators, a non-contact braking distance measuring device based on infrared ranging principle is designed. Futher, a quantifiable risk assessment method of brake based on failure mode and effects analysis (FMEA) is propose in this paper. Characteristics and trends of distance changes during emergency braking process of the escalator are theoretically analyzed. To extract, process, and recognize the distance change signals, and finally to realize accurate measurement of the braking distance, a high-speed infrared distance measurement technology is used. Influencing factors of the escalator brake performance are studied. The risk analysis method based on FMEA is used to analyze its failure mode, failure mechanism, and consequences of the failure. A risk index assessment system is constructed and quantified. The test results show that the measurement error of the device designed is 1.6%, which is 1/6 of the traditional measurement method. The repeated measurement error of the device is 1.4%, which is 1/7 of the traditional measurement method. Application results show that the quantifiable risk assessment method quantifies and assigns the risk level according to the weight, which effectively avoids the inconsistent results caused by human bias. The evaluation results are more scientific and reliable.