【摘要】 为实现逆向工程中未知自由曲面高效、高精度的数字化测量,提出一种基于探路法的自适应采样方法。在接触式测头(Touch probe,TP)的两侧各安装一个点激光测头(Point laser probe,PLP),建立坐标转换模型将各个测头的测量值统一到基准坐标系下。逐行采样过程中,在测量方向上,PLP用于探路测量,系统实时地对探路测量数据进行处理并拟合成B样条曲线,根据拟合曲线的曲率特征为TP测量规划合理的测量路径,TP以探路结果为指导完成自适应采样。在测量截面进给方向上,通过截面间夹角分析,自适应地细分测量截面。仿真和试验结果表明,该方法能根据曲面特征合理地布置采样点,有效地提高未知自由曲面数字化采样的效率和精度,为逆向工程提供良好的采样数据。更多还原

【Abstract】 In order to realize high-efficiency and high-accuracy digital measurement unknown free-form surfaces in reverse engineering, an adaptive sampling method based on front path detecting is presented. The method is characterized by integration of one touch probe(TP) and two point laser probes(PLPs). The two PLPs are located on both sides of the TP. A coordinate transformation model is built to transform these three probes’ measurement results into a reference coordinate system. In the process of line-by-line sampling, at the measuring direction, the PLPs are used to detect the measuring path information in front of the TP, the data acquired by the PLPs is processed and fitted into B-splines instantaneously, and then the TP measuring path planning can be generated according to the curvature feature of the fitted B-splines. The obtained path detecting information is subsequently used to automatically guide the TP to achieve adaptive sampling. While at the cross-section intake direction, "cross-section angle" analysis algorithm is used to subdivide the cross-sections adaptively. Simulation and experiment results indicate that the sampling points generated by the TP are laid out rationally according to the curvature of the surfaces, and demonstrate that the sampling efficiency and accuracy can be improved significantly, and effective sampling data can be offered for reverse engineering.更多还原