车辆操纵稳定性的动态仿真与研究

1、 2922 Farong Kou et al. / Energy Procedia 13 (2011 2916 2924 Farong Kou et al. / Energy Procedia 00 (2011 000000 7 Fig.7. Vehicle test instruments Step-input test for coach is performed in 75km/h speed and 1.4 rad steering wheel angle. Steering wheel angle is transformed as nominal fore wheel turn a

2、ngle f by transmission ratio of 20.2:1. Nominal fore wheel angle used in simulating input is given as 0 (0 t 0.2 = f 0.0691(t 0.2 (0.2 < t 1.20 (t > 1.20 0.0691 (30 The results of tests and simulations are shown in fig.8. Horizontal ordinate stands for time t and longitudinal ordinate stands f

3、or yaw rate r and nominal fore wheel angle. 8 2 7 1 6 5 4 3 2 1 0 -1 -1 a b 6 5 4 3 2 1 0 -1 -1 a b 7 1 6 5 4 3 2 1 0 -1 -1 b a 8 2 8 7 1 2 r ( °/s and f ( ° r ( °/s and f ( ° 0 1 2 time (s 3 4 5 0 1 2 time (s 3 4 5 r ( °/s and f ( ° 0 1 2 time (s 3 4 5 1 Yaw rate test

4、result; 2 Yaw rate simulation result a Nominal fore wheel turn angle of test input; b Nominal fore wheel turn angle of simulation input Fig.8. (a six degree of freedom model ; (b seven degree of freedom model ; (c nine degree of freedom model Through the comparisons between simulation curves and tes

5、t curves, it is obvious that simulation results of nine-degree of freedom model of coach greatly approach test results. Overshoot of simulation of nine-degree of freedom model curve is much little and simulation curve appears convergence trend. 4. Simulating analysis of coach handling and stability

6、under operating mode of avoiding obstacle The following dynamics simulations, under running mode of dangerous avoiding obstacle, are carried out by using nine-degree of freedom model of coach which was proved to be valid. Input function of drivers avoiding obstacle operating mode, which is nominal f

7、ore wheel angle of used simulating input, is written as 8 Farong Kou et al. / Energy Procedia 13 (2011 2916 2924 Farong Kou et al. / Energy Procedia 00 (2011 000000 2923 (0 t 0.2 0 0.0691(t 0.2 (0.2 < t 1.20 (1.2 t 3.2 f = 0.0691 0.0691(t 3.2 + 0.0691 (3.2 t 4.2 (t 4.2 0 (31 The dynamics simulati

8、on under running mode of avoiding obstacle is completed at 85km/h speed with different stiffness lateral stabilizer rod being fixed in coach fore axle, the results of which are given in fig.9. 0.5 c1=159030Nm/rad c1=268590Nm/rad c1=378160Nm/rad 7 c1=159030Nm/rad c1=268590Nm/rad c1=378160Nm/rad 0 Lat

9、eral deviation angle of coach center of mass deg 6 5 -0.5 Coach roll angle deg 4 -1 3 -1.5 2 -2 1 -2.5 0 -3 -1 0 1 2 3 Time s 4 5 6 0 1 2 3 Time s 4 5 6 Fig.9. (a response curve of lateral deviation angle of coach; (b response curve of roll angle of coach 5. Conclusions Coach dynamics models of poly

10、-degree of freedom are established based on the analysis of coach structure and load. Passenger body models are built and subsequently verified. The tests of real vehicle are done on the testing road and the effectiveness of established models is validated. Under operating mode of dangerous avoiding

11、 obstacle, coach dynamic simulations are carried out by using nine-degree of freedom model of coach which was proved to be valid. The simulating results show that handling and stability of coach is obviously improved when lateral stabilizer rod is fixed. Stiffness increasing for lateral stabilizer r

12、od, further enhances coach running stability. Lateral deviation angle of coach center of mass drops and the amplitude of coach weaving is reduced. Acknowledgements This work was financially supported by 2010 Chinese post doctor scientific fund(20100481310 , Shaanxi education department scientific research plan-science special (2010JK660, the doctor initial fun