Inertia Parameter Identification Of Mining Dump Truck's Sprung Mass Under Random Road Excitation

Mining dump truck is an important transport equipment of modern mines,and in order to improve the independent research and development capability of mine dump truck in our country,the mining dump truck is classified as major technical equipment by State Congress in key areas,which put forward higher requirements on the performance of mining dump truck.With the deepening research on the performance of the mining dump truck,the accuracy of dynamic model is of the increasingly high demand.The accuracy and efficiency of the dynamic model are directly affected by the precision and method of the dynamic parameters's acquisition.The inertia parameters of the sprung mass play a decisive role in the stability of the vehicle and have a direct effect on the vehicle's handling characteristics,ride comfort,power,fuel economy and active control.It is also an important parameter for the modeling and analysis of the vehicle dynamics.At present,the inertia parameters of the vehicle sprung mass are mainly measured by direct method and indirect method.The direct method refers to the measurement of the inertia parameters in the test bench,this method is very high accuracy.However,due to the large volume and mass of the mining dump truck,the investment cost of the bench is high,so it is difficult to measure the inertia parameters of the sprung mass directly.The indirect method is mainly based on the longitudinal dynamics or manipulating dynamics of the vehicle under the specific working condition.However,the indirect method depends on accurate measurement of the air resistance,rolling resistance,slope resistance,engine output torque and other parameters,and can only identify part of the inertia parameters,such as the mass.the pitch and roll moment of inertia can not be identified.Mining dump truck runs on the mine random road all the year round.The random road excitation is a kind of environmental excitation,can comprehensively stimulate modal information of the sprung mass.On the basis of accurately obtaining the modal parameters of sprung mass,reasonable construction of the relationship between the modal parameter and the inertia parameter of sprung mass can be used to identify more inertia parameters of the sprung mass theoretically,it has great research value.Therefore,this paper presents a method to identify the inertia parameters of mining dump truck's sprung mass with only measurement of acceleration responses of sprung mass under random road excitation,which is significant to improve the accuracy of dynamic modeling and the level of development.Main contents of this paper are as follows:1.According to the difference of frequency domain power spectral density between the random road excitation and the white noise excitation,the response under random road excitation is pretreated by short frequency window filtering and wavelet decomposition,and NExT(Natural Excitation Technique)technology to extract the equivalent impulse response is improved,and an equivalent impulse response extraction method for random road excitation is proposed.2.Based on free vibration model of multi degree system and the complex mode-state space theory,the relationship between the modal parameter and the inertia parameter of sprung mass is constructed.Combined with time domain modal identification ITD method(The Ibrahim Time Domain Technique),an inertia parameters identification method under random road excitation is proposed.3.Considering the coherent characteristics of left and right track,the random road excitation of four wheel vehicle is simulated.The simulating generation is used as the input of example models to simulate the acceleration response of sprung mass.By identifying the inertial parameters of example models,the correlation relationship between modal parameters and inertia parameters and the inertia parameters identification method under random road excitation is verified as precise and effective.And the identification ability of the method is analyzed at different random road grades and vehicle speeds.4.Design vehicle driving test under random road,when analysing test data,it is found that the zero drift trend is obvious and the high frequency noise is more.First,the least squares method is used to eliminate the zero drift trend of the acceleration test data.The low-pass filter is used to filter out the frequency signal of 2Hz or more,highlighting identification frequency range vibration mode of sprung mass.And then the wavelet threshold method is used to denoise the identification frequency range test data.Comparing the denoising effect of soft threshold method and hard threshold method to obtain the best denoising results for the follow-up work.5.The inertia parameter identification model of the dump truck's sprung mass is established,then the inertia parameters of sprung mass during unloading and overloading are obtained.Based on the identification result of sprung mass's inertia parameters,the dynamic model of the electric wheel dump truck-random road is established and simulate the working condition during unloading and overloading under random road excitation.The reliability of the identified inertial parameters of the dump truck'sprung mass is verified by comparing the simulation vertical acceleration response of the front-left suspension upper,rear-left suspension upper and rear-right suspension upper with the denoised test data during the same working condition.