A signal-based fault detection method for bolster springs on heavy haul wagons

摘要

A signal-based fault detection and isolation (FDI) system is proposed for heavy haul wagons in this paper. Such systems, to be feasible on freight wagons, must be as cheap and as robust as possible, so the design assumes the constraint of using only two accelerometers which are mounted on the front left and right rear part of each carbody. The focus of this paper is the detection of bolster spring fault conditions. The problem is made more complex by the modes of failure which might be expected in bolster spring nests. Types of spring failure are firstly identified and discussed covering situations of broken (shortening springs) and softening (individual spring loss from a nest or cross section loss through corrosion). The effects of these faults and their detectability were investigated using simulations on straight and curved track and using a fully detailed model of a typical 40t axle-load heavy haul wagon. The simulation results were then examined and compared using correlation analysis and a FDI system was proposed. The FDI system introduced 5 possible fault indicators (FIs). Initial results indicated that it was possible to detect changes in bolster stiffness of ±25%.