一种R-test球头球心检测装置结构优化设计方法

基于数控系统绕刀具中心旋转(Rotation tool center point，RTCP)功能，R-test装置被用于多轴联动数控机床的联动精度检测与标定。该仪器通过三个直线位移传感器测量安装于主轴的球头球心空间位置，从而可测量机床多轴联动时的刀具中心点位置误差。在分析测量原理的基础上，提出最大测量空间和测量敏感度的两个用于评价测量性能的指标及相应的数值算法，得到一种R-test装置结构优化设计方法。在选择通用球头芯棒与长度计的情况下，通过约束分析得到测量杆安装圆直径、测量杆与基准面夹角两个关键尺寸的设计区间，利用蒙特卡罗法搜索得到这两个关键尺寸的最优解，完成结构优化设计。仿真表明，优化设计得到的R-test测量装置具有最佳的测量敏感度，可测区域大于半径为4 mm的球体，能满足实际测量精度和测量空间需要。

An Optimum Structural Design Method of R-test Ball Sphere Center Measuring Device

Based on the rotation tool center point (RTCP) function of NC system, R-test device has been used in accuracy inspection of multi-axis movement and calibration of multi-axis machine tools. Three linear displacement sensors are used in this device to measure the sphere center in X, Y, and Z directions of a reference ball attached to the machine’s spindle, thus the tool center point (TCP) can be measured during the machine’s multi-axis movement. Based on the analysis of measuring principle, a structural optimization method for R-test device is obtained. Two indices thus maximum measuring space and measuring sensitivity are designed to evaluate the measuring performance, and the numerical algorithm of these two indices are also got. By analyzing the restraint state of the measuring limbs and the measured ball, the design ranges of two key dimensions thus the diameter of the measuring limbs’ located circle on the reference plane and the angle between the measuring limb and the reference plane are got. In the condition of choosing the normal ball-bar and length measuring meters, these two key dimensions’ optimal solutions are calculated by Monte Carlo method, and the structure optimization is finished. Simulation shows that this R-test device has the best measuring sensitivity and the maximum measuring space which is larger than a spherical space whose radius is 4 mm, and it can satisfy the actual need of measuring accuracy and size.