A Universal Algorithm for Bias-Chord Offset Based on MCO and Its Characteristics Analyses
Hu Wei · Tiedao gongcheng xuebao · 2013
Research purposes: There are two methods for alignment and profile irregularities evaluation of HSR ballastless track,i. e. mid-chord offset( MCO) method and bias-chord offset differential method. MCO method has been applied in track survey field widely,but the application of bias-chord offset differential method was limited due to its dependence of absolute survey. From the mathematical model of two methods,this paper analyzed the geometric interpretations of two methods to provide the theoretical basis for HSR ballastless track irregularity evaluation.Research conclusions:( 1) On this basis,a universal algorithm for chord deflection offset was established which is based on short chord MCO data. The result of computer simulation has verified the accuracy of the universal algorithm.( 2) By means of frequency characteristics and error characteristics analysis,this paper argued that: contrast with bias-chord offset differential method,MCO method has some characteristics in the same chord length,e. g. zero phase shifting,richness of irregularities information,location convenience and characterization of dynamic properties. Not only that,the MCO method is able to extract the information of long wave irregularities with extended algorithm.( 3) The universal algorithm established in this paper should provide a new method for the measurement of chord deflection offset in HSR survey.