Performance Evaluation for an Elevator by Analyzing the Vibration Data of the car

Elevators have become an essential means of transportation for people living in high-rise buildings, but many elevators are getting old and of poor performance and which may lead to fatal accidents, thus elevators need to be evaluated for safety purposes to be decided to use further or replace them. Currently, the elevator is evaluated by experts according to national or local laws and rules, the evaluation process is time-consuming, and the results from different experts may be different, there is a lack of useful evaluation methods for elevators. In this paper, an evaluation method for elevator performance based on the improved Grey Relational Analysis (GRA) by analyzing the vibration data of the car of an elevator is proposed. Firstly, the relationship between the vibration and the performance is analyzed. The vibration data of the cars of three selected elevators in 300 days was collected, and then the features of the vibration data are analyzed and the sensitive ones are selected as the evaluation indexes. Secondly, a hybrid combining Weight-Minkowski and Distance-Improved GRA performance evaluation method is constructed for elevators’ performance evaluation, in which, the entropy method and interval analytic hierarchy process (IAHP) are combined to give the weight for the selected features. And then, the Weighted GRA is calculated by using the Minkowski distance which can consider the influence of the fluctuation of the gray relational coefficient of each feature to evaluate the performance. Finally, the proposed method is verified by serval other elevators in service as well as an experimental one. The results show that the proposed method can improve the accuracy of the evaluation results compared with the traditional GRA as well as the Weighted GRA method, matching well with the real health states of the elevators being evaluated. The proposed method can be used not only for evaluating the performance of an elevator but also for other traction-drive machines, for example, mining lifts, etc.