整车质心测量精度的研究

Research on Measurement Accuracy of Vehicle Center of Mass

整车质心测量方法(举升法和摆锤法)都存在以下一种或几种问题:测量过程中前后悬架压缩、轮胎变形和摩擦力变化等,带来X、Y和Z方向质心测量偏差过大的问题,这些偏差都会成倍冗余在各个模块的设计和验证中,影响项目进度、成本和开发周期。文章通过研究当前测量方法的测量过程,结合实车物理结构的分析,再对比理论数模数据和实车测量结构,总结出上述问题产生的原因。通过建立刚性连接机构解决测量过程中弹簧和轮胎的变形问题;设计专用机构把轮胎滑动摩擦力转化成轴承的滚动摩擦力,减小内摩擦力和反作用力方向不能确定的问题;通过设备上的位置感应器和倾角测量仪校准,减少举升高度和倾斜角度在测量中的偏差。通过上述措施和方法可以提高测量精度。

There are one or more of the following problems in the vehicle centroid measurement methods(lifting method and pendulum method):during the measurement,the front and rear suspension compression,tire deformation and friction change,etc.They cause the problem that the measurement deviation of centroid in X,Y and Z directions is too large.These deviations will be multiplied and redundant in the design and verification of each module,which will affect project schedule,cost and development cycle.This paper mainly studies how to solve the above problems.By studying the measurement process of current measurement methods,combined with the analysis of the physical structure of the real vehicle,and then comparing the theoretical digital analog data with the real vehicle measurement structure,we summarize the causes of the above problems.We solve the deformation problem of spring and tire in the measurement process by establishing a rigid connection mechanism.A special mechanism is designed to convert the sliding friction of the tire into the rolling friction of the bearing,so as to reduce the problem that the direction of internal friction and reaction force cannot be determined.Through the calibration of the position sensor and inclination measuring instrument on the equipment,the deviation of lifting height and inclination angle in the measurement can be reduced.Through the above measures and methods,the measurement accuracy can be improved.