Rollover Risk Research On Dual-axle Truck With High Center Of Gravity

The economy of China is developing at break-neck speed and the area of freight transportation is increasingly widespread while the number of commercial vehicles is rising quickly.But the rollover of the vehicles with high center of gravity would lead to serious consequences,including mortal incidences and property losses.In some situations,including sharp steering and serpentine steering,the peak value of oscillating LTR of vehicles may exceed the critical point even the prediction of steady state is safe.Meanwhile,the resonant frequency of sprung mass' rolling motion,is also desicive to vehicle rollover.But the existing research have hardly considered these two factors' influence on vehicle's rollover.To determine the resonant frequency of roll motion and peak value of LTR,the steering model with two degrees of freedom and roll model with single axle were established firstly in this dessertation.Based on these models,the second order transfer function between steering input and LTR output were built to determine the resonant frequency.The steering input of sharp steering and serpentine steering was simulated and,using Fourier transformation,its spectrum and auto-power spectrum were derived to analyze the potential risk of a specific input according to resonant frequency.Finally,the variation of roll angel,roll rate and LTR in time domain can be determined and then the peak value of LTR will be confirmed.And simulation experiments under critical conditions of rollover was carried out to test the accuracy of resonant frequency and LTR peak value prediction.At the same time,a scaled model was established and the measure process of its relative parameters and control program of motors were introduced while the similarity between simulation model and scaled model was validified by Buckinghan theory.According to simulation and experiments,using this predict system,the peak value of LTR during steering can be effectively determined with driver's input,while the resonant frequency also have desicive influence on rollover.Subsequently driving advices or judging basis could be provided to human driver or rollover control system,respectively.