Rollover Estimation And Research On Reliability Of Rollover Prevention For Semi-trailer Tractor At High Speed

Because of high centroid position and complex structure, in the case of avoiding obstacles and overtaking at high speeds or high speed turning,, compare with Single freight vehicle, tractor semi-trailer is more easer to loss lateral stability, produce folding, tailing flick, yawing, rolling and other phenomena. And it is easy to occupy other vehicle lane, cause more serious traffic accident. So, rollover estimation and research on reliability of rollover prevention for tractor semi-trailer at high speed, is great research value. This paper studies the rollover estimation and reliability problem of tractor semi-trailer through virtual simulation technology. The simulation of reliability used to control system, can be made rollover warning advance, in order to reduce the probability of occurrence of rollover risk, for achieving better securityFirstly, this paper establishes the linear mathematical model of three degrees of freedom of tractor semi-trailer, establish the simulation model in Simulink. Simulation results show that the three degree of freedom model is established under some conditions, can simulate the motion characteristics of tractor semitrailer well.Secondly, analyze and compare the extended calman filter (EKF) and the unscented calman filter (UKF) estimation, compare the advantages and disadvantages, finally choose the unscented calman filter (UKF) to estimate and analyze. State equations of three degree of freedom tractor rollover model through the matlab program to discrete, then set up the state linear equations and linear measure equation with noise loading items. Then, use unscented calman filter (UKF) to estimate the three degree of freedom tractor rollover model, compared with the established simulation model in simulink, Analyze estimate results, at last, use unscented calman filter (UKF) to estimate transverse acceleration, high center of gravity, load transfer rate (LTR) for 100 times,1000 times,10000 times simulation.Finally, use method of reliability to calculate and analyze the results of unscented Calman filter (UKF) estimation for load transfer rate (LTR). For the initial velocity 15m/s(54km/h), the steering angle of the front wheel step input is 0.05rad,, a simulation method of Monte-Carlo is used to simulate load transfer rate (LTR) for 100 times,1000 times,10000 times, then use method of reliability to analyze the LTR by numerical simulation. Then simulate the front wheel angle sinusoidal input, the sinusoidal peak is 0.05rad, period is 5s, a simulation method of Monte-Carlo is used to simulate load transfer rate (LTR) for 100 times,1000 times,10000 times, then use method of reliability to analyze the LTR by numerical simulation. The simulation results, an approximate probability or reliability index is a better method to estimate the risk of heavy vehicle rollover, this can be used for rollover warning and control system.