The Study On SBW System Front Steering Angle And Road-feel Simulation

As the highest form of steering system,the SBW(Steering-by-wire)system connect the steering wheel with steering actuators by electronic control technology,instead of the traditional mechanical connection.Itget rid of the limitations of traditional mechanical steering system,and the angular velocity ratio can be designed freely,meanwhile the SBW system can balance the force transfer characteristics and angle transfer characteristics,it makes steering system more humanized,it has huge development prospects.As following,several contents have been researched based on the summary of domestic and foreigndevelopment situation of the steering technology and research method.First of all,set up a SBW system simulation model.According to the characteristics of the SBW system,based on the idea of order-reduced,divided steering system into three parts:steering wheel assembly,actuator and motor.Using Simulink to build each part simulation model of SBW system.Adopt double closed loop method to control the executive motor and road-feel motor,and get the PID parameters of each motor.At the same time,using the vehicle system dynamics simulation software CarSim build the vehicle simulation model,and through relevant interface achieve CarSim/Simulink co-simulation.And then,the model was verified by the DLC(double lane-change)test,the results show that the model is reasonable,it can replace the mechanical steering system to steer and get reasonable road feel,for follow-up study of control strategy laid a foundation.Secondly,SBW system front wheel angle control strategy was studied.In order to analyze the mechanical steering sensitivity characteristics,different speed and steering wheel angle step simulation test was carried out.Thenthe concept of ideal angle ratio is introduced,put forward two kind of method to get the ideal velocity ratioand compares the result of them,finally get the ideal velocity ratio of SBW system.According to the ideal velocity ratio to calculate the front wheel angle primarily,then a TWO-DOF multi-body dynamics model for reference,based on yaw rate and side-slip angle front wheel angle control strategy was designed to get the ideal front wheel angle,after that though DLC test and sine-wave test the control strategy are verified,the results show that the control strategy can achieve the desired effect.At the last,SBW system road feeling strategy was studied.After introduce the concept of steering system road feel,analyze it'smechanism of production,influence factors and the requirement of road feel,for the mechanical steering vehicle sine steering angle input test were carried out in different speed,then analyzethe characteristics of the mechanical steering,based on this,road feel planning was put forward which mainly focus on the steering gear resistance torque and considerate the speed,steering wheel angle,lateral acceleration comprehensively,andeach value of parameter were determined.Finally,using several kinds of typical working conditions to verify this control strategy,the results show that the effectiveness of the control strategy.