利用测头等效法确定激光单点测头的方向

提出了一种利用测头等效法和迭代标定法确定激光单点测头方向的方法。该方法通过求解从激光测头的一维坐标向三维坐标转换的变换矩阵确定激光测头在测量机直角坐标系中的方向。利用测头等效法将激光测头等效为接触式测头,保证它在标定过程中的测量值不变,使其能测量空间的一个固定点,从而确定了求解变换矩阵的“共轭对”;利用迭代标定法保证了“共轭对”的确定满足测头等效条件,使变换矩阵的解(激光束的方向)逐步趋近于理想值。实验表明,当测头的一维测量精度为0.0128mm时,利用变换矩阵转换得到的三维数据的精度为0.0173mm,这证明利用该方法所确定的激光单点测头的方向具有较高的精度。

Study on determining the direction of laser beam sensors via equivalent-probe approach

An equivalent-probe and iterative-calibration approach for determining the direction of a laser beam sensor is proposed. By solving the matrix from transforming the 1-D data of laser sensor into 3-D data, the direction of the laser sensor in the Cartesian coordinate of a coordinate measuring machine (CMM) is determined. According to equivalent-probe principle, the laser sensor is regarded as an equivalent contact trigger probe when measuring different points at a fixed working value. This enables the sensor to measure a fixed point, and the conjugate pairs from solving the transforming matrix are determined. An iterative calibration approach is applied to ensure the condition of probe equivalent when determining conjugate pairs. With the increase of iteration times the solution of the matrix tends to an ideal value. Experiment shows that the accuracy of 3-D data transformed from 1-D laser value is 0.0173mm while the accuracy of the laser sensor is 0.0128mm. This demonstrates that the direction of the laser beam sensor determined via the proposed approach possesses high accuracy.