多轴轮式工程机械动力学建模及制动性能仿真

为了预先掌握多轴轮式工程机械制动性能,指导制动系统设计,以某四轴轮式工程机械为对象,考虑了地面附着条件、质心位置、制动产生的轴荷转移等因素,进行了制动性能仿真研究。通过车轮坐标系与整车坐标系映射关系,对悬挂和车轮的小变形作线性假设,建立了整机在制动稳定极限状态下的动力学模型,利用MATLAB/Simulink分析附着系数、质心相对位置、制动初速度对制动距离的影响,并将仿真结果与试验结果进行了对比。结果表明：仿真结果与试验结果吻合良好;随地面附着系数和质心距离第Ⅰ轴中心线位置的增加,整车制动距离减小;随制动初速度和质心距离地面高度的提高,整车制动距离增加;相对静止状态,制动过程中第Ⅰ轴和第Ⅳ轴轴荷变化最显著。

Dynamic Model and Braking Performance Simulation of Multi-axle Wheeled Engineering Machine

In order to predict the braking performance of multi-axle wheeled engineering machine and provide reference for the brake system design,a four-axle wheeled engineering machine was set as the object,simulation study on braking performance of the machine was carried out after considering the influence of the adhesion coefficient,the location of the machine’s mass center and the axle-loads shift.Based on the relationship between relative coordinates for wheels and absolute coordinates for whole machine,and the hypothesis of small compression deformation of the suspensions and tyres that is linear,dynamic model for the machine was proposed under its braking stability limit state.Brake distance influenced by different adhesion coefficients,the relative location of the mass center and the braking velocity were analyzed with MATLAB/Simulink.The simulation results and the experiment results were compared.The results show that the simulation results coincide with experiment results.The brake distance decreases with the increase in adhesion coefficient and in the longitudinal location of the mass center relative to the I axle center,while the brake distance increases with the increase in the height of the mass center and in the brake velocity.And Ⅰ axle-load and Ⅳ axle-load vary sharply during the process of braking.