| How to improve the roll stability and anti-rollover ability of vehicles has become a research hotspot in the field of automobile active safety.This paper comprehensively considers the influence of human-vehicle-road factors on the anti-rollover control and researches on the integrated control of rollover and yaw stability,the coordinated control of roll stability and path tracking,and the coordinated control of roll stability and path tracking considering the driver in the loop.The specific research work is summarized as follows(1)To solve the coupling problem of roll stability control and yaw stability control,an integrated stability control strategy is proposed.The lateral offset of the zero moment point is selected as the rollover index,and then a two-dimensional map based on the rollover index and the yaw rate error is designed.Based on the two-dimensional plan,four control modes are divided: yaw stability control,roll stability control,roll-yaw stability control,anti-rollover control,and the switching rules between control modes are established.Then,the centralized drive electric vehicle is taking as the research object,and the differential drive based on direct yaw moment control(DYC)is employed to improve yaw stability,the roll stability is improved via longitudinal speed control,and the DYC-based single-wheel braking is utilized to prevent rollover.The co-simulation results based on Car Sim and Simulink show that compared with the traditional fuzzy PID control,the root means square(RMS)value of yaw rate error is reduced by about 30%,and the RMS value of roll angle is reduced by about 4.01%.Therefore,the proposed integrated control strategy can reduce rollover risk and improve yaw stability.(2)Aiming at the conflict between roll stability control and path tracking,a longitudinal coordinated control strategy is proposed.Firstly,the path tracking problem is transformed into a yaw rate tracking problem,and the expected yaw rate generation method considering lateral stability is designed based on the back-stepping method.Then,a path tracking controller based on model predictive control(MPC)is designed.The roll stability control and path tracking are weighted and fused by using the weight coefficient,and the longitudinal control is used to coordinate the relationship between path tracking target and stability control.The co-simulation results based on Car Sim and Simulink show that compared with the autonomous steering,the RMS values of yaw rate error and rollover index are reduced by about 36.30% and 1.32%,respectively while ensuring the path tracking performance.Therefore,the proposed control strategy can coordinate the relationship between roll stability control and path tracking.(3)Aiming at the existing researches on vehicle rollover prevention control rarely consider the influence of driver factors on vehicle roll stability,a roll stability and path tracking control strategy based on human-machine shared control is proposed.Firstly,the machine intervention timing is determined according to the path tracking deviation.The lateral offset of the preview point and the human-machine conflict degree are used to determine the weight of the driver and the steering controller based on the fuzzy control method.The human-machine cooperative steering control is used to improve path tracking accuracy.The rollover risk is reduced based on the single-wheel braking of the rear wheel and the conflict with the front wheel steering is also reduced.Then,an integrated steering and braking control strategy based on MPC is designed for automatic driving under emergency conditions.The co-simulation results based on Car Sim and Simulink show that the path tracking accuracy is increased by about11.94%,3.89% and 49.75%,respectively compared with the individual control of drivers with a neural response delay time of 0.2 s,0.3 s and 0.4 s.The proposed control strategy can adapt to different types of drivers,reduce the rollover risk and improve the path tracking accuracy.Finally,the research contents and innovation points of the dissertation are summarized,the shortcomings of the research are pointed out,and then some suggestions for future research are given.Figure [38] Table [9] Reference [121]... |
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