Performance Degradation Monitoring for Onboard Speed Sensors of Trains

Photoelectric speed sensors (PSSs), which are used for velocity measuring and positioning, are key components of train control systems. In real applications, the performance of PSSs may degrade, such as the decrease in the number of the output pulses, which is caused by the existence of jammed code tracks on the shading plates of PSSs. Considering this kind of performance degradation, this paper proposes an online performance-degradation-monitoring approach that can detect the existence of the jammed code tracks and estimate the number of them. Based on the results from the performance-degradation-monitoring approach, this paper also provides a compensation algorithm for the distorted speed readings resulting from the existence of the performance degradation. The results from the mathematical analysis and numerical examples verify the effectiveness of the proposed performance-degradation-monitoring approach for PSSs.