大曲面检测技术研究

大曲面的检测对于三坐标测量机是一个难题,以电子经纬仪作为传感器的工业测量是一种新的方法,可以解决这个难题.这种测量属于非接触测量,因此被测工件的状态是不受约束的.另外一个优点是它可以在较大的测量范围内达到较高的测量精度.在本文中,检测了处于架设状态下的大曲面,同时研究了相关的检测技术.由于直接得到的测量结果是采样点的三维坐标,所以首先需要分析其坐标与被检测量之间的关系,根据曲面的特征,其坐标偏差的标准偏差值作为评价型面质量的参数;然后建立相应的检测系统.在建立的过程中,需要考虑检测精度和曲面与经纬仪的位置关系.检测结果表明,这些技术可以实现对大曲面的高精度检测,并且具有广泛的应用前景.

MEASUREMENT OF SURFACES HAVING LARGE RADIUS OF CURVATURE

Measurement of curved surface having large radius of curvature is a problem for a three coordinates measuring machine. The measured surface could not be larger than the machine and should be set at a level position. An industrial measurement system with electronic theodolites as sensors is a new way to solve this problem. It belongs to the non-contact measurement systems, so the measured piece could be freely set. The system has larger measurement range and higher precision. Erected curved surfaces have been measured and some techniques of measurement were discussed in the paper. The measured results directly given from the measurement system are the three coordinates of sampling points. Analysis of the relationship between these coordinates and the surface to be measured are first necessary. According to the surface characters, the standard deviation of all sampling points coordinates are selected to evaluate its surface precision. Then, the measurement system is set up. Measurement precision and surface characters should be considered before setting up the system. Results of measurement show that these measures could achieve purposes in curved surface measurement and have wide applications.