基于微粒群算法的汽车底盘控制系统集成优化

为了消除汽车底盘集成系统机械与控制系统间的耦合,该文首先建立了汽车悬架与制动系统动力学模型,分别设计了主动悬架和防抱死制动系统的子控制器和该系统的集成协调控制器。针对传统汽车底盘集成系统的机械与控制参数采用串行设计容易失去全局最优性能的特点,提出一种基于微粒群优化算法的参数的集成优化方法,以集成系统机械与控制参数为优化变量,以反映汽车动力学综合性能为目标函数,编制了集成优化程序进行了优化仿真计算。仿真结果表明:汽车底盘集成系统经过参数优化后,汽车的俯仰角加速度较优化前减小,表明汽车乘坐舒适性得到改善;汽车制动时制动距离、前后轮动载荷均有明显减小,表明汽车制动的安全性显著提高。最后改变汽车的部分机械结构参数和全部控制参数进行实车试验,试验结果表明:汽车底盘集成控制系统经过优化后,汽车的前、后轮动载荷分别降低了34.2%和32.1%,汽车制动时制动时间和制动距离分别降低了2.31%和4.5%,汽车制动时俯仰角加速度响应降低了15.1%,汽车主动安全性及汽车舒适性均得到了不同程度的改善和提高。优化设计方法对改善汽车底盘主动安全性具有重要参考意义。

Simultaneous optimization design of vehicle chassis integrated control system based on particle swarm optimization algorithm

Abstract: With the application of active control technology in vehicle, the performances of vehicle such as riding comfort, active safety and handling stability were greatly improved in recent years. However, most of these control systems were aimed to improve individual performance of vehicle respectively. In fact, the improvement of the overall vehicle dynamics performance not only depends on the cooperative work among these various control subsystems but also depends on the coupling interferences of the mechanical structure and control system of vehicle in the running process. In order to remove the coupling interferences between the mechanical structure and control system of vehicle chassis system and to further enhance the overall performance of vehicle, the method of simultaneous optimization of mechanical structure and controller parameters of vehicle chassis system based on Particle Swarm Optimization Algorithm is presented in this paper. According to the fundamental principle of vehicle dynamics, a half car mode of active suspension system and anti-lock braking systems established at first. Then the linear quadratic gauss controller of the active suspension system and sliding mode controller of anti-lock braking system are designed. Taking controllers designed for active suspension system and anti-lock braking system as bottom controllers, the upper coordinated control logic of the systems is put forward and the upper PID coordinated controller is designed on the basis of analyzing the coupling conflict between active suspension system and anti-lock braking system. Finally, a Particle Swarm Optimization Algorithm was adopted for simultaneous optimization of mechanical structure and controller parameters of vehicle chassis integrated control system, because the traditional design method of a vehicle system is always to design control parameters following structure parameters and it can not obtain the global optimal performances for the system. In order to verify the effectiveness of the algorithm, the simultaneous optimization program is developed based on Particle Swarm Optimization Algorithm in MATLAB environment while the mechanical structure and control parameters of chassis control system are set as optimization variables and the overall vehicle dynamics performance is set as objective function. Simulation result shows that the pitching angular acceleration of vehicle is reduced and vehicle riding comfort performance is improved after optimized. Braking distance and dynamic load of front and rear wheels of vehicle are also reduced significantly which indicating vehicle active safety is improved dramatically. The vehicle road test was also carried out based on integrated controller is development of anti-lock braking system and active suspension system using ARM7 when vehicle speed is 40 km/h under braking condition. The road test also shows that the dynamic load of front and rear wheels of vehicle are reduced by 34.20% and 34.10%, braking time and braking distance of vehicle were reduced by 2.31% and 4.50% respectively, the response of vehicle pitching angular acceleration at braking condition is decreased by 15.10% after optimized, and both vehicle active safety and riding comfort are improved at different levels..