Research On The Influence Of Suspension K&C Characteristics On Tracking Performance Of Autonomous Sightseeing Vehicle

Autonomous driving is the future development trend of automobiles,and trajectory tracking performance is one of the important properties of autonomous vehicles,and the handling stability dynamics model plays an important role in it.Existing automatic driving algorithms mostly use different degrees of freedom mathematical models for algorithm development,but most of them ignore the suspension structure and believe that the tire mechanics characteristics are linear,which leads to large errors between the model and the actual vehicle.In order to improve the trajectory tracking accuracy from a theoretical point of view,this paper analyzes the influence of suspension K&C characteristics on the trajectory of the car by quantitatively expressing the changes of wheel positioning parameters and tire mechanical characteristics,and realizes that the simulation model has better tracking performance on the actual trajectory.Firstly,the mathematical model theory of three-degree-of-freedom handling stability considering roll,side and yaw is introduced.The motion equation is given and the corresponding simulation model is established in MATLAB.Introduce the characteristics of suspension K&C characteristic analysis and main working conditions,and explain how toe angle,camber angle,kingpin parameters,etc.affect the performance of the whole vehicle.For a certain type of self-driving sightseeing car,design experiments to measure its front and rear suspension hard points and vehicle parameters.Establish the front and rear suspension and vehicle dynamics models in ADAMS/car.Carry out the simulation analysis of suspension K&C characteristics,and obtain the gradient values of toe angle,camber angle,kingpin parameters,etc.with the wheel load.The curve of tire cornering stiffness and camber stiffness with vertical load is obtained by magic formula.Carry out real-vehicle angle step,angle pulse and steady-state rotation tests according to the national standard,and fit the real vehicle angle to the input model,simulate the three-degree-of-freedom model and the ADAMS model,compare the result curves and quantitative evaluation parameters,and verify the built ADAMS The accuracy of the multi-body dynamics model ensures that the K&C characteristic parameters obtained through ADAMS simulation have certain accuracy.Starting from the understeering degree,the influence of the suspension K&C characteristic parameters on the handling stability is analyzed,and the conclusion is drawn that the toe angle and the camber angle change gradient value are introduced into the model.The suspension K&C characteristic parameters and the influence of wheel load transfer are added to the three-degree-of-freedom mathematical model,and the simulation model is established in MATLAB.The simulation model before and after considering the suspension K&C characteristics and the actual vehicle trajectory deviation value were compared under the snaking and double shifting conditions to study the influence of the suspension K&C characteristics on the vehicle trajectory tracking performance.