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 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 for yaw rate r and no

3、minal 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 result; 2 Yaw rate simulation result a Nominal fore wheel t

4、urn 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 test curves, it is obvious that simulation results of nine-deg

5、ree 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 under operating mode of avoiding obstacle The following dyn

6、amics 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 fore wheel angle of used simulating input, is written as 8 F

7、arong 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 simulation under running mode of avoiding obstacle is completed at 85km/

8、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 Lateral deviation angle of coach center of mass deg 6 5 -0.5 Coach

9、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-degree of freedom are established based on the analysis of coac

10、h 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 obstacle, coach dynamic simulations are carried out by using ni

11、ne-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 rod, further enhances coach running stability. Lateral deviation

12、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 fundin