通过对多轴转向车辆数学模型进行简化,获得某型号五轴全路面起重机的二自由度操纵动力学模型,并基于零质心侧偏角控制策略推导出各后轮转角与前轮转角及车速的函数关系.在对比例阀和转向执行机构(液压缸)进行简化的基础上,在Matlab/Simulink中建立了转向系统完整的数学模型.为克服传统PID控制器的缺点,基于Matlab模糊逻辑控制模块建立了转向系统模糊自适应PID控制器,对PID控制器各个控制参数进行在线整定,以此获得较高的控制精度.以25km/h速度下稳态回转试验对该控制器进行仿真验证.经过仿真分析后发现,该模糊控制器取得很好的效果,系统响应迅速,跟随性好,完全能满足控制需要.

A 2-DOF model of the five-axle all terrain crane with some simplifications is proposed, and based on the assumption of zero side-slip angle of mass center and the proportional control strategy, the function relating the angles of the rear and the front axles, and the velocity are derived. With some simplifications with respect to the proportional valve and the cylinder, a mathematical model of the steering system in Matlab/Simulink is established. In order to overcome the weakness of the traditional PID controller, a fuzzy adaptive PID controller of the rear axle steering angle is built in Matlab by using its fuzzy logic control toolbox. Through the real-time determination of the PID parameters, a high control precision is achieved. A steady state cornering simulation is carried out under 25km/h, and the comparison of the simulation and theoretical values shows that the fuzzy adaptive PID controller works well, with quick system response and good following performance.