Research On Integrated Control Methods For Horizontal And Vertical Motion Of Smart Cars

With the advancement of science and technology, intelligent vehicle is inevitable for the development of the automobile industry. As the combination of multi-disciplinary advanced technology, intelligent vehicle has brought new ideas and methods to solve the increasingly serious traffic problems. Nowadays, there are many key technologies that need to be optimized. Intelligent control of vehicle movement is one of the crucial technologies of intelligent vehicle research, which directly determines whether the vehicle is running at a desired state of mankind. In this thesis, the research on the method of controlling vehicle motion is carried out aiming to establish a comprehensive control system for the vehicle lateral and longitudinal movements.Three dynamics models need to be established based on the idea of intelligent control system in this thesis: Decoupled lateral and longitudinal independent dynamics models and globe dynamics model. Based on a range of assumptions, the lateral dynamics model of the relative position of the vehicle and the road centerline, and the longitudinal dynamics model of longitudinal dynamics and powertrain dynamics were established, which were modeled in MATLAB / Simulink. Taking the accuracy of vehicle globe dynamics model into account, in AMESim software a vehicle fifteen degrees of freedom vehicle model was built. The establishment of three dynamics models laid the foundation for the design of the control system.Analyzing the impact that the vehicle parameters have on the lateral dynamics, in order to reduce the uncertainty of the model, the longitudinal speed is divided into four intervals. Corresponding controllers of each sub-interval model was designed based on fuzzy logic control. In order to avoid the peak appear during the interval switch, a fusion block was designed. So the lateral control system was accomplished. The longitudinal controller was designed based on hierarchical structure. The Constant Time-gap spacing policy was chosen as the upper controller. A coordinated accelerate and brake controllers based on fuzzy logic was proposed. And considering the logic switch to coordinated the accelerate and brake actuators which considered vehicle state, the appropriate scenarios were set in the MATLAB/Simulink, and the results showed that the design of the lateral and longitudinal independent control systems work well.Combing the lateral and longitudinal control system, the coupling of control system was achieved by setting speed as the combination point. Through the co-simulation of MATLAB/Simulink and AMESim, the vehicle globe control system was designed. Typical vehicle operating conditions was set and the debug of the vehicle globe control system was completed. The simulation results show that the globe control system works well.In order to verify the feasibility of the globe control system, intelligent vehicle actuators were designed based on dSPACE rapid control prototyping on a real vehicle. The RCP on real vehicle test showed that the actuator movements can accurately follow the output of the globe control system, which proved the feasibility of the globe control system.