Research On The Roll Stability Of Passenger Cars Based On ECAS

Due to its high quality,high center of gravity and narrow track,heavy passenger cars are prone to instability during high speed driving.Especially in the case of a turn,the vehicle is easy to roll over and causes a great loss to the driver’s life and property safety.Aiming at this problem,this paper establishes an air spring charge and discharge model,a vehicle sevendegree-of-freedom vertical dynamics model and a vehicle nine-degree-of-freedom roll model.On this basis,the vehicle anti-rollover control strategy is designed.According to the stiffness and height adjustable characteristics of the air spring,the anti-rollover capability of the vehicle is improved.The main contents of the paper are as follows:(1)Introduce the air suspension and classify the air springs,analyze the gas pressure in the air spring and the effect of the effective area on the stiffness and natural frequency of the air spring,and establish an air spring according to the air spring.The first theory of thermodynamics and other related theories.The charge and discharge model provides the basis for the vehicle’s charge and discharge model.(2)According to the knowledge of vehicle dynamics,the four-wheel road excitation model is derived based on the single-wheel road excitation model.At the same time,a vehicle tire model was established.On this basis,the seven-degree-of-freedom vertical dynamics of the passenger car was established.The passenger car model and the nine-degree-of-freedom roll model use Trucksim to validate the established seven-degree-of-freedom model and the ninedegree-of-freedom roll model to provide passengers with basic vehicle rollover control.(3)Select the vehicle anti-rollover evaluation index and study the vehicle system dynamics in depth.When the vehicle reaches the roll threshold,the air spring is charged and deflated to change the center of mass of the vehicle and change the stiffness of the air spring to improve the stability of the vehicle.gender.The air spring air mass flow is controlled by a PWM control algorithm to prevent vehicle overshoot.When the vehicle’s center of mass reaches the target height,the optimal anti-rolling control force required by the vehicle is determined by a microdecomposition coupling genetic algorithm,and the main power is distributed to the left and right suspensions.The vehicle passes through the force distributor and uses the left and right air suspension.A corresponding main power is generated to form an additional torque,thereby achieving an anti-rollover effect of the vehicle.(4)Using MATLAB / simulink to establish the vehicle roll model and the vehicle air suspension charge and discharge model,increase the above anti-rollover controller,and perform simulation analysis under the angle step condition.The results show that the stability of the vehicle roll under the anti-rollover control algorithm is improved based on ECAS.