The Lateral And Longitudinal Dynamic Control Method Of Autonomous Vehicle Based On State And Parameter Estimation

The main function of lateral and longitudinal dynamic control is to make the vehicle track the reference trajectory safely and reliably.It is vital for lateral and longitudinal control to adopt the appropriate vehicle dynamic model and control method.In addition,the accurate state and parameter of vehicle are also the key input.The paper takes the intelligent connected vehicle platform as the research object and study the problem of lateral and longitudinal dynamic control for autonomous vehicle base on state and parameter estimation.The main research has the following four points.(1)The state and parameter estimation method based on adaptive unscented Kalman filter(AUKF).A derivative fault-tolerant noise statistic estimator and AUKF are adopted to estimate the center of mass position,coefficient of road adhesion,tire cornering stiffness,tire vertical force and road slope.Simulation and experiment results show that this method can give precise dynamic parameter input to lateral and longitudinal controllers.(2)Lateral control method based on the optimal front-tire lateral force.Focusing on the large lateral acceleration condition,a lateral control method for autonomous vehicles based on the optimal front-tire lateral force is proposed in the paper.By constructing the LQR controller based on the feedforward and feedback,the desired front-tire lateral force is solved online in real time.By combining the state and paramete such as vertical tire-force,tire cornering stiffness and coefficient of road adhesion,the method can not only reduce the path tracking error,but also ensure the steerability and the lateral stability of the vehicle.(3)Longitudinal control method based on the desire driving and break force compensation.To improve the accuracy and robustness of controller,the paper apply the hierarchical control structure.The lower controller uses PI controller to control the throttle and brake pedal to track the desired speed,and finally to achieve accurate longitudinal dynamic control.The upper controller adopts the longitudinal control method with desire driving force and break force compensation based on fuzzy system to realize the accurate longitudinal control in rampway.(4)The experiment research based on intelligent connected vehicle platform.The method of estimation and control is verified simultaneously.The experimental results show that the vehicle state and parameter estimation method can estimate the road adhesion coefficient,tire cornering stiffness,vertical tire-force,and road slope accurately.The presented lateral dynamic control and longitudinal dynamic control strategy can effectively tracking desired trajectory in the diffierent typical conditions,which has high engineering application value.