采用标准长度的激光多边法坐标测量系统自标定算法

基于多路激光跟踪干涉仪测长的坐标测量系统在大尺寸测量领域具有显著的优越性,准确标定系统参数是实现高精度坐标测量的关键。为了克服传统自标定方法的缺点,提出了一种采用标准长度的改进自标定算法。该算法首先在稳定的基座上设置固定点,在X、Y、Z方向分别产生用激光干涉法精确测得的标准长度,然后将标准长度用于构造自标定的优化函数。通过提高相应优化函数的权重,进一步提高坐标测量精度。通过仿真实验证明了该算法的可行性。采用独立的激光干涉仪验证系统在大尺寸范围内的测量精度,当测量点分布在距系统坐标系原点［7.0 m,8.3 m］区间内,两组实验误差均分布在［-9.5 μm,4.6 μm］区间内,结果表明所提出自标定算法可显著提高大尺寸空间坐标测量精度。

Self-calibration Algorithm for Laser Multilateral Coordinate Measurement System Using Standard Length Method

The coordinate measuring system based on laser multilateral tracking method has remarkable superiority in the large scale measurement filed,and the accurate calibration of system parameters is the key to achieve high-precision coordinate measurement.To overcome the shortcomings of the traditional calibration method,an improved self-calibration algorithm by using standard length is proposed. Firstly,a number of fixed points are set in the stable base,and the accurately standard lengths along X,Y,Z directions are measured using laser interference method respectively.Then the standard lengths are used to constructed self-calibration optimization functions.By increasing the weight of the corresponding optimization function, the coordinates measurement accuracy is improved further.The feasibility of the algorithm is verified through simulation experiments.Also,the actual experiments are conducted to verify the measurement accuracy of the developed system in large scale range.By comparing with independent laser interferometer measurement results, the error of two groups are distributed in the［-9.5 μm, 4.6 μm］ range as the distances between the compared points to the origin of the coordinate measure system are distributed in the［7.0 m,8.3 m］ interval. The results show that the measurement accuracy of large scale coordinate significantly is improved by the proposed self-calibration algorithm.