一种形位不确定回转壳体内壁表面的激光测量与重构方法研究

Laser Measurement and Reconstruction Method Research for a Kind of Rotary Shell′s Inner-surface with Uncertain Configuration

针对形位不确定回转壳体内表面的测量及重构问题,提出了一种准在线纵截线测量与曲面重构方法.通过粗、精测量相结合的实现过程,首先根据技术文件提取回转壳体的基本信息,并针对内表面存在的不确定性,建立一种模糊调节规则,对回转壳体内表面的形位进行预测,实时调整激光测量的角度与位置,完成测量.搭建激光测试试验平台,开发了模块化的测试平台软件系统.采用所提方法对回转壳体内表面进行测量试验研究,得到待测回转壳体内表面的三维数据,并进一步根据回转曲面二次加工的要求对曲面的重构方法进行分析,重构回转壳体内壁的三维曲面实体模型.试验结果表明,曲面模型的相对误差绝对值平均值小于0.024%.

According to configuration uncertainty of a kind of rotary shell＇s inner surface, a laser measurement and reconstruction method based on quasi-online longitudinal curve for the inner- surface is proposed in this paper. The whole laser measurement is implemented in virtue of two steps. One is coarse measurement process, the other is precise measurement process. In coarse process, the basic information of the rotary shellls inner-surface is picked up from its technical file. For the uncertainty of the inner-surfacefs configuration, a fuzzy prediction algorithm for the actual inner-surface is applied for precise measurement process. The measurement position of inner surface in next sampling time is predicted based on fuzzy reasoning. The measurement is accomplied through adjusting of projecting angle and location of laser sensor depending on the prediction algorithm. The laser experimental platform is set up. Its software system is developed. Experimental research of the proposed method are carried out by means of the test platform. The three-dimensional data are obtained from coarse and precise measurement process. The measurement and reconstruction method is evaluated in terms of secondary processing requirement. The 3D model of the rotary shell~ s inner-surface is reconstructed by using appropriate measurement and reconstruction method. The experimental results verify that the proposed method reveals better performance. The mean absolute difference rate of the model is less than 0. 024 %.