Research On Vehicle Dynamics Control Algorithm Considering Driver Characteristics

According to the report of the accident statistics,most of the traffic accidents are related to the wrong operation of the driver,especially under the limit condition of the vehicle.In the wrong operation of the process,the driver's reaction delay is one of the important factors.This delay involves the driver's brain response,the brain to the actuator and the actuator delay.The length of the delay varies greatly under different environmental conditions,Driving experience,the driver's mental state and road conditions will interference to the driver's reaction,even is likely to cause a great impact on the vehicle handling and stability,even lead to the occurrence of unsafe condition such as sliding and overturning.Therefore,it is an important research direction of vehicle active safety to consider the delay of the driver.This paper mainly studies the influence of driving factors on the handling and stability.Using the control algorithm to reduce the consequences caused by the driver delay,in order to improve the vehicle handling performance and stability.In this paper,steer-by-wire control method and Smith compensation control method are adopted to deal with the robustness of driver delay difference.The main work of this paper includes the following aspects:(1)Build an integrated model of vehicle,tire and driver considering driver delay characteristics.The vehicle yaw dynamic model is established by analyzing the dynamics of vehicle steering process.The tire nonlinearity is linearized by using fuzzy method,and take the tire characteristics into the vehicle yaw dynamics equation through the value of cornering stiffness.The model of the driver track is established,and the influences of the driver's delay on the vehicle handling and stability are studied by simulating the track process.(2)By using the linear matrix inequality theory and steer-by-wire method,a new robust controller is designed to improve the vehicle handling and stability.The theory and theorem of linear matrix inequalities are studied,and the vehicle yaw motion is represented by linear matrix inequalities.The stiffness of the tires is estimated and tracked on the basis of the Luenberger observer,and these values are used for the design of the robust control algorithm.This algorithm can realize the automatic control of weight distribution between the yaw rate and sideslip angle.Through this algorithm,the controller can achieve the control performance of the vehicle in the normal situation,while when the vehicle reaches the control limit,the controller can help the driver to prevent the occurrence of instability of the vehicle.(3)The long delay of the driver in the process of steering is dealt by Smith compensation principle,and PID control algorithm is adopted to deal with the mismatch between the Smith compensator model and the actual model.The delay of the driver's steering process is processed by the system uncertainty theory,and the stability range of the PID controller parameters is determined by the frequency analysis method.The PID controller and the Smith compensator are utilized to control the steering behavior of the driver to achieve the better control of the vehicle.The feasibility of the control method is verified by simulation.(4)Through the four wheel independent drive electric vehicle platform,the differential steering experiment is carried out to verify the control algorithm,in addition,the vehicle yaw motion and hardware in the loop simulation are also studied and explored deeply.In this paper,the Matlab/Simulink and Dspace controller are used in the hardware in the loop simulation.The characteristics of acceleration,steering and braking are analyzed through the open loop experiment.Through the closed-loop experiments,the constant yaw rate and the variable yaw rate are tracked respectively,research and analysis of front wheel differential steering is studied by lane changing experiment,S-shaped road experience and J-turn experience.