基于模式切换的汽车自适应巡航系统分层控制

Research on hierarchical control of automobile adaptive cruise system based on mode switch

汽车自适应巡航系统通过分层控制即上层控制器向下层控制器(节气门或制动执行器)发出指令,实现汽车自动加速、减速或保持车速不变,以保持后车与前车间的期望距离。文章将自适应巡航汽车的控制模式划分为速度控制模式和车距控制模式,考虑到2种模式之间的博弈,根据车距与相对速度之间的关系建立2种模式之间的切换策略,以实现速度控制模式和车距控制模式间的平稳切换;再利用PI(proportional integral)控制和模糊控制对期望加速度进行控制,完成上层控制器的建立;根据刹车油门切换逻辑区分期望加速度和期望减速度,建立下层控制;最后利用CarSim和Matlab/Simulink软件对自适应巡航汽车的行驶工况进行联合仿真,仿真结果表明该控制策略能使后车较为稳定地跟踪前车。

Automobile adaptive cruise system sends commands from the upper controller to the lower controller（throttle or brake controller） through the hierarchical control, which enables the automobile to accelerate, decelerate or keep constant speed automatically in order to maintain the desired distance between the automobiles. The adaptive cruise control modes are divided into the automobile speed control mode and automobile distance control mode. Considering the game between the two modes, the switch strategy is established according to the relationship between the distance and the relative velocity to achieve a smooth switch between the automobile speed control mode and automobile distance control mode. The desired acceleration in different modes is controlled by the proportional integral（PI） control and fuzzy control so as to establish the upper controller. The desired acceleration and desired deceleration are distinguished according to the switching logic between the brake and the accelerator to obtain the lower controller. Finally, the simulation on the adaptive cruise automobile in different conditions is carried out by using the CarSim and Matlab/Simulink software. The results show that the automobile tracks the one ahead steadily by the proposed control method.