汽车线控转向系统自适应变增益传动比设计OA北大核心CSTPCD

The variable steering transmission ratio was a crucial factor affecting the active safety and handling sta-bility of vehicles.In order to enhance the steering characteristics of steering-by-wire vehicles on low-adhesion coef-ficient road surfaces,a variable gain transmission ratio that adapts to changes in road adhesion coefficient and vehi-cle speed was designed.A 2 DOF model was established for the vehicle,to analyze the factors influencing the yaw rate gain,and to obtain the data relationship between the influencing factors and the gain through simulation.The Min-Max normalization method was utilized to preprocess the data between the influencing factors and the yaw rate gain,constructing a neural network dataset.Design a Snake Optimizer Backpropagation Neural Network(SO-BP)was desighed and train to use the preprocessed dataset to dynamically acquire the variable yaw rate gain.A strategy was employed to combines the variable yaw rate gain with the lateral acceleration gain in proportion to design the variable gain transmission ratio for electronic control steering.Simulink-CarSim was used to build a steer-by-wire steering whole vehicle model.Compare and analyze the designed variable gain transmission ratio was analized and compared with a traditional fixed gain transmission ratio under conditions of both high-adhesion coefficient road sur-faces with a double lane change scenario and low-adhesion coefficient road surfaces with a step input scenario.Re-sults indicated that with high-adhesion coefficient road conditions,the trajectory error of the two transmission ratio vehicles remained within 3%,while the variable gain transmission ratio vehicle reduced the peak steering wheel an-gle by 9.1%.With low-adhesion coefficient road conditions,the variable gain transmission ratio vehicle showed a 22.3%reduction in steady-state yaw rate at low to moderate speeds and a 24.6%reduction in peak yaw rate.At moderate to high speeds,the steady-state yaw rate decreased by 6.6%,and the peak yaw rate decreased by 10.8%.The variable gain transmission ratio not only enhanced steering sensitivity on high-adhesion coefficient road surfaces,but also improved safety and maneuverability when driving on low-adhesion coefficient road surfaces.