基于蒙特卡洛模拟的夹具定位误差分析与预测

Prediction and Analysis of Fixture Positioning Error Based on Monte Carlo Simulation

分析包含零点定位系统的发动机缸盖"一面两销"夹具定位误差机理;以多体系统约束理论以及运动学原理为基础,建立夹具定位误差与各定位元件位置以及制造偏差的关系模型。针对汽车发动机缸盖夹具,利用MATLAB蒙特卡洛模型对14个误差源进行随机取样,并多次模拟求解预测工件位姿误差;对比传统误差计算方法,该模型分析全面且精度更高;利用数值模拟及统计回归方法,分析各误差源对工件整体位移误差以及整体姿态误差的敏感性分布;为夹具综合设计过程中,公差选配具有理论指导意义。

Analyzing the positioning error mechanism of engine cylinder head "one side two pin" fixture, which contains a zero-positioning system. based on the multi-body system constraint theory and kinematics principle, the relationship model between the workpiece pose error and the error of each positioning component is established. For the engine cylinder head clamp, the Monte Carlo model is used to generate multiple sets of random error values for each error source and the simulate workpiece pose error. Compared with the traditional error calculation method, this model is more comprehensive and accuracy. By means of numerical simulation and statistical regression method, the sensitivity distribution of each error source to the overall displacement error and the overall attitude error of the workpiece is analyzed, which has theoretical guiding significance for the selection of tolerances in the process of fixture comprehensive design.