Lateral And Longitudinal Integrated Control Of Driverless Cars Based On Model Predictive Control

With the increase of car ownership year by year,more and more traffic problems have been exposed.In recent years,in order to solve these problems,driverless car technology has become the focus of research by government agencies,enterprises and university research institutes.Among them,the horizontal and vertical motion control problem,which is the lower level in driverless vehicle technology,is the core of research.At the same time,since the horizontal and vertical motion of unmanned vehicles will interfere with each other,it is very necessary to conduct research on the comprehensive horizontal and vertical motion control of unmanned vehicles.In this paper,based on the model predictive control algorithm,the lateral,longitudinal and integrated controllers of unmanned vehicles are designed to solve the motion control problem of unmanned vehicles with strong nonlinearity and strong coupling.The main research contents of this paper are as follows:(1)Firstly,the three cores of model predictive control are expounded.These three cores are: predictive model,rolling optimization and feedback correction,and the necessity and principle of linearization and discretization are mainly introduced in the part of predictive model.The construction process of the lateral and longitudinal dynamic models of the whole vehicle is described,and the dynamic models of the transmission system and the braking system are built for the lower longitudinal motion controller.Finally,the construction method of the co-simulation experiment platform is briefly stated.(2)Linearization and discretization are carried out for the built vehicle lateral dynamics model,and then a lateral motion controller is designed according to the obtained prediction model.The controller optimizes and solves the steering wheel angle according to the related vehicle state parameters,thereby control the vehicle.Finally,the co-simulation experiment is carried out by selecting the double line-moving path as the desired trajectory.Finally,the co-simulation experiment is carried out by selecting the double line-moving path as the desired trajectory.The results show that the lateral controller designed in this paper can realize the lateral motion control of the vehicle,and can also meet the constraints set for comfort.(3)When facing the longitudinal dynamics model of the whole vehicle,a special method is used for linearization,and then a prediction model is obtained after discretization.According to the prediction model,a longitudinal upper motion controller is designed,and the controller solves the required driving force or braking force,and the corresponding throttle valve opening or brake master cylinder pressure is solved by the longitudinal lower motion controller.Finally,some working conditions of NEDC are selected for co-simulation experiments.The results show that the longitudinal controller designed in this paper is designed in this paper.The longitudinal motion control of the vehicle can be realized,while also meeting the constraints set for comfort.(4)In the end,this paper selects the vehicle longitudinal speed as the coupling point of the lateral and longitudinal control,and designs a lateral and longitudinal integrated motion controller combined with the previously designed lateral and longitudinal motion controllers.The results show that the comprehensive control of the vehicle’s lateral and longitudinal directions can be realized,and at the same time,it can meet the requirements of comfort.Finally,by calculating the time spent in each controller solution,it shows that the lateral and longitudinal integrated motion controller designed in this paper can meet the real-time performance.requirements.