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Study on Automatic Centering Operations of Varieties of Workpieces Based on Non-linear Dynamic Analyzes of Contact Surfaces

基于接触面非线性动态分析的多种工件自动定心操作研究

基本信息

批准号：
03650104
负责人：
YOSHIMURA Masataka
金额：
$ 1.34万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

The centering operation of workpieces is one of the most time-consuming jobs for which automation has not been established in Computer-Aided Manufacturing (CAM). As fundamental research for automating the centering operations, analytical models and methodologies needed for automating centering operations were proposed. First, the movement behaviors of a workpiece when applying an impulse force with a hammer were observed using experimental equipment and the relationships between the applied force and the displacement of the workpiece were measured. Then, frictional forces between a workpiece and a table were formulated as a nonlinear function of the velocity of the workpiece. Next, to obtain a displacement behavior of the workpiece on a table numerically, the movement of the workpiece was simulated by the finite element method (FEM) in which a nonlinear frictional force model was applied at the contact surface between the workpiece and the table. Finally, a method was constructed for determining the optimal impulse force for displacing a workpiece to a required postion on a table so that the positional error of the workpiece was minimum and numerical results were given to demonstrate the method. The results obtained by this study are itemized as follows :(1) A frictional force model with four parameters of static frictional coefficient, dynamic frictional coefficient and two parametric values expressing the rising speed of the frictional force function was constructed.(2) Computer simulation of workpiece displacement behaviors was conducted using the frictional force model and the finite element method. The simulated results have a good agreement with the measured ones.(3) A method for determining the optimal impulse force for displacing a workpiece to a required position on a table was constructed and the method was demonstrated using numerical results.

工件的定心操作是计算机辅助制造（CAM）中尚未建立自动化的最耗时的工作之一。作为对中操作自动化的基础研究，提出了对中操作自动化所需的分析模型和方法。首先，使用实验设备观察用锤子施加冲击力时工件的运动行为，并测量施加的力与工件的位移之间的关系。然后，工件和工作台之间的摩擦力被公式化为工件速度的非线性函数。接下来，为了以数值方式获得工件在工作台上的位移行为，通过有限元法（FEM）模拟工件的运动，其中在工件与工作台之间的接触表面应用非线性摩擦力模型。最后，构建了一种确定将工件移动到工作台上所需位置的最佳冲击力的方法，以使工件的位置误差最小，并给出了数值结果来验证该方法。研究结果如下：（1）建立了由静摩擦系数、动摩擦系数四个参数和两个表示摩擦力函数上升速度的参数值组成的摩擦力模型。（2）利用摩擦力模型和有限元方法对工件位移行为进行了计算机模拟。仿真结果与实测结果吻合较好。(3)建立了一种确定将工件移动到工作台上所需位置的最佳冲击力的方法，并用数值结果对该方法进行了验证。