Modeling And Synthesis Of Super-Gaussian Road Profile Under Vehicle-Road Coupling

Power spectral density(PSD)is widely used to describe the statistical characteristics of road roughness,and its implicit assumption is that road roughness follows Gaussian distribution.The practice shows that the road profile excitation often presents a significant super-Gaussian random characteristic when the vehicle is driving on the complex roads,which is influenced by the continuous irregular convex pavement and the speed change.However,the current study does not consider the coupling effect of the speed change and road profile transformation on the super-Gaussian road profile model,and the proposed super-Gaussian road profile models do not have the generalization ability.Therefore,focusing on two aspects in this paper: the modeling method of super-Gaussian random signal in time domain and the synthesis method of super-Gaussian road profile in spatial domain.A new method of modeling and synthesis of super-Gaussian road profile under vehicle-road coupling is proposed,which not only improves the accuracy of road profile modeling,but also lays the foundation for vehicle-road collaborative control and improves the durability of vehicle design.This paper mainly carries out the following work:(1)Studying the characteristic statistics describing the time-frequency domain of the road profile signal,such as skewness,kurtosis,power spectral density and probability density function(PDF),etc.Based on these key statistics,the fatigue characteristics of Gaussian and super-Gaussian road profile signal are analyzed,and the methods of frequency domain and time domain to calculate fatigue damage spectrum(FDS)of different road profile signals are used.(2)Focusing on the modeling method of super-Gaussian random signal based on amplitude modulation,and a new linear combination modulation modeling method based on Weibull distribution and Beta distribution is proposed,which can not only solve the problem of narrow kurtosis coverage of the existing methods,but also ensure that the high kurtosis value of the super-Gaussian signal is correctly transmitted to the structural response by controlling of spectrum components and cumulative distribution function(CDF)of the amplitude modulation signal(AMS).(3)Based on the conversion relationship between time domain,frequency domain and spatial domain,the super-Gaussian signal modeling method is transformed into super-Gaussian road profile modeling method.By introducing the international roughness index(IRI),a modeling method of super-Gaussian road profile based on modified Gamma distribution is proposed,and finally the modeling and synthesis of super-Gaussian road profile is realized.(4)A new super-Gaussian signal modulation modeling method based on the linear combination of Weibull distribution and Beta distribution,as well as the super-Gaussian road profile modeling method based on the measured IRI and modified Gamma distribution were tested experimentally.The effectiveness of the two new methods was verified.