Abstract: In order to improve the function of adaptive cruise control (ACC) system, a modeling and hierarchical control method for ACC system is investigated in this paper. Firstly, a 14 DOF vehicle dynamics model is established with considerations of longitudinal, lateral and vertical coupling characteristics, and according to the physical characteristics of electronic throttle and brake system，an actuator model, which can accurately track the desired input，is also built. Then an inverse dynamics model is set up, which includes drive / brake switching logic, inverse engine model and inverse brake model. Finally aiming at the functional requirements of ACC system, the robust lowerlayer controller accommodating different working conditions is designed by applying model matching control theory, while the upperlayer controller can get the desired vehicle following acceleration, comprehensively considering vehicle distance, relative velocity and ego vehicle acceleration based on linear quadratic optimal control theory. Simulation results show that the ACC system can make vehicle maintain good tracking and adaptive performance in different driving conditions covering acceleration, steady following and deceleration.

Key words: ACC system, vehicle dynamics modeling, hierarchical control, robust control, linear quadratic optimal control