The Research Of AFS Control Strategy Based On The Hardware-in-the-loop System

Vehicle horizontal pendulum control is related to vehicle driving safety in the process of actual use. If the car yawing angular velocity does not accord with the established target value, the result will be a driving steering control problem or serious consequence. By active front wheel steering system(AFS- Active Front Steering), through the Active Steering and variable ratio intervention, the vehicle could obtain the ideal Steering characteristics. Under different speed conditions, it can satisfy people’s demand for automotive steering. It also played a key role to ensure the safety of car driving and improve the drivers’ working conditions. Based on steering stability and security, the happening of the accident is avoided to the greatest extent. The active steering system is a main trend of the current and future development. Therefore it is important to carry out the AFS active safety studies.The topic is on the basis of some car enterprise test control project. The hardware in the loop simulation system is set up, the AFS control strategy model is established, and the control system performance is analyzed, so as to provide theoretical basis and technical support for the development of AFS.The following work is conducted in this thesis.First, the CarSim software is employed to establish the whole vehicle model, and at the same time, working condition of completed vehicle as well as the construction of the road is set up. The MATLAB/Simulink is used to design with front wheel angle controller programming, and CarSim input/output interface is connected with it.Secondly, according to the fuzzy theory, the AFS controller based on fuzzy control and simulation analysis is designed. Through the comparison of simulation results, it can prove the effectiveness of the proposed control strategy. And the yawing angular velocity algorithm and ackermann Angle algorithm in the input of fuzzy control strategy are established, to ensure the precision of the system.The third is hardware in the construction of the ring system, and debugging the connections between hardware and software. Through this platform,the established vehicle model is applied to test the real-time performance of system.Finally, based on co-simulation CarSim with LabVIEW, the hardware signal and simulation system are debugged for validation. And within the lower machine, the artificial real-time running is conducted to test the validity of the platform, further testing AFS control strategy. Through software simulation and hardware in the loop simulation, the two items verified the effectiveness of the control strategy at the same time.