Yaw Stability Control Of Four Wheel Independent Drive Vehicle Based On Sliding Mode Variable Algorithm

Focusing on the instability safety of four-wheel independent drive vehicle under extreme working conditions,this paper maily analyzes its unique advantages in direct yaw moment control,studies and designs the means of controlling the yaw stability,and achieves the manipulating constancy within ultimate hazardous operating mode through the controller.Yaw rate and the sideslip angle of mass center should be taken as the core parameters,which are reflected and controlled by the model.Employ the 2-DOF vehicle model as the nominal consult model,export theoretical value,apply the 7-DOF vehicle model as the practical vehicle model fitting the four-wheel independent drive vehicle,outlet the veritable value;analyze the wheel dynamic state and select the tire model and motor model scheme;construct the model through Matlab and Car-Sim Software,and simulate and verify it.Using sliding mode variable algorithm and hierarchical control,the yaw stability operator is devised.Projecting a status observation equipment to evaluate and reckon the core control outcomes;selecting different sliding surfaces and reaching laws to design the upper additional yaw moment controller,calculating the supplementary yaw moment demanded for the automobile to maintain stable driving under the two models,and constructing the corresponding matlab model.The lower controller inputs the additional yaw moment.This paper designs an optimal distribution scheme based on quadratic programming,compares the distribution methods based on hydraulic braking,axle load ratio,average distribution and minimum road adhesion consumption,and imports them into Matlab and Car-Sim after modularization,and carries out simulation verification of yaw stability under the working conditions of double transfer line surface and serpentine road surface.The simulation gains manifest that in terms of yaw stability control,the four upper layer control schemes designed in this paper are better than no control schemes.Specifically,in terms of the two core parameters,they can maintain the instability boundary range,reduce the peak value and well follow the ideal value under the reference model.The design of the four upper schemes can be compared to select the best scheme.In the matter of yaw moment distribution,the curves of the lower distribution scheme based on quadratic programming are smoother and more reasonable than the contrast scheme chosen in this paper.