Weigh in motion based on dynamic tire force separation

Abstract

Dynamic tire forces are the main factor affecting the measurement accuracy of the axle weight of moving vehicles. This paper focuses on separating dynamic tire forces from axle-weight signal, and proposes a new method to measure the axle weigh of vehicle based on improved EMD (empirical mode decomposition). First, the characteristics of axle-weight signal and related concepts and process of EMD are briefly introduced. Then the causes and the influences on weighing accuracy of end effect and pseudo-IMF (intrinsic mode function) are analyzed in detail. The AR (auto-regressive) model prediction method and the correlation coefficient method are employed to extend the data points outside of signal end points and judge the pseudo-IMFs, respectively. The pseudo-IMFs and the residual are added to form a new residual, and the average value of new residual is regarded as the axle-weight estimation. Lastly, the simulation and real experiments are given to illustrate the proposed method. The max weighing error of axle-weight is 4.34% at the speed no higher than 20km/h. © 2011 Springer-Verlag Berlin Heidelberg.