Research On Trajectory Tracking Control Of Intelligent Vehicle

Relying on the continuous development and growth of new technology,the intelligent vehicle industry attracts more and more capital to join in,and it has broad development prospects.The motion control algorithm is one of the key parts in the field of intelligent vehicle technology,in the actual,individual lateral or longitudinal control can not meet the actual needs,so it is necessary to combine lateral control with longitudinal control.The main research content of the paper is intelligent vehicle trajectory tracking control,in order to achieve this purpose,lateral controller and longitudinal controller were designed respectively,and lateral and longitudinal cooperative control was carried out at last.This process mainly includes the following aspects:(1)The lateral and longitudinal dynamic models of the vehicle were established.Lateral dynamic model was established on the basis of the two-wheel model of the vehicle,and the longitudinal dynamic model mainly includes the whole vehicle model and the power transmission system model,in which the power transmission model includes the inverse brake and inverse engine model.(2)The lateral controller was designed.The lateral dynamic model is a kind of mismatched uncertain system with uncontrollable disturbance.Firstly,the matrix transformation method was used to decompose the unmatched uncertainties,and then the vehicle lateral controller was established based on the robust control theory,the matching part was eliminated by integral sliding mode control,and the unmatched part was suppressed by H_∞ control.After that,the robustness of speed and road adhesion coefficient was verified,and the road is double moving line.The results showed that the controller could track the desired path well and was robust to vehicle speed and road adhesion coefficient.(3)The hierarchical structure was adopted in the design of vehicle longitudinal controller.The upper controller adopts MPC control,the output is the desired acceleration,and the lower controller includes brake/acceleration switching logic and inverse dynamic model.The switching module will select the braking/acceleration mode according to the desired acceleration,and the inverse dynamic model can obtain the desired throttle opening or brake master cylinder pressure.The simulation results showed that the longitudinal controller could switch between braking and acceleration,and could track the given reference speed curve including multiple acceleration segments stably and quickly.(4)Simulation verification of lateral and longitudinal cooperative control.First of all,based on the two dangerous working conditions of roll and side slip,the critical speed model of the vehicle driving on the road was deduced,the longitudinal speed was selected according to the critical speed model.Then the road environment was set,and the road environment adopted two kinds of working conditions:double-shift line and curve track.The results showed that compared with the lateral control,the lateral and longitudinal cooperative control could greatly improve the vehicle trajectory tracking accuracy and driving stability,and had significant advantages over the single lateral control.