Structural dimensional inspection is vital for the process monitoring, quality control, and fault diagnosis in the mass production of auto bodies. Comparing with the non-contact measurement, the high-precision five-axis measuring machine with the touch-trigger probe is a preferred choice for data collection. It can assist manufacturers in making accurate inspection quickly. As the increase of free-form surfaces and diverse surface orientations in auto body design, existing inspection approaches cannot capture some new critical features in the curvature of auto bodies in an efficient way. Therefore, we need to develop new path planning methods for automated dimensional inspection of free-form surfaces. This paper proposes an optimal path planning system for automated programming of measuring point inspection by incorporating probe rotations and effective collision detection. Specifically, the methodological contributions include: (i) a dynamic searching volume-based algorithm is developed to detect potential collisions in the local path between measurement points; (ii) a local path generation method is proposed with the integration of the probe trajectory and the stylus rotation. Then, the inspection time matrix is proposed to quantify the measuring time of diverse local paths; (iii) an optimization approach of the global inspection path for all critical points on the auto body is developed to minimize the total inspection time. A case study has been conducted on an auto body to verify the performance of the proposed method. Results show that the collision-free path for the free-form auto body could be generated automatically with off-line programming, and the proposed method produces about 40% fewer dummy points and needs 32% less movement time in the auto body inspection process.

中文翻译：

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自由曲面自动尺寸检测的最佳路径规划

结构尺寸检测对于汽车车身大规模生产中的过程监控、质量控制和故障诊断至关重要。与非接触式测量相比，带触发式测头的高精度五轴测量机是数据采集的首选。它可以帮助制造商快速进行准确的检查。随着汽车车身设计中自由曲面和多样化表面方向的增加，现有的检测方法无法以有效的方式捕捉汽车车身曲率中的一些新的关键特征。因此，我们需要开发新的路径规划方法，用于自由曲面的自动尺寸检测。本文通过结合探针旋转和有效的碰撞检测，提出了一种用于测量点检测自动化编程的最佳路径规划系统。具体而言，方法论贡献包括：(i) 开发了一种基于动态搜索体积的算法来检测测量点之间局部路径中的潜在碰撞；(ii) 提出了一种结合探针轨迹和触笔旋转的局部路径生成方法。然后，提出检测时间矩阵来量化不同局部路径的测量时间；(iii) 开发了车身上所有关键点的全局检测路径的优化方法，以最小化总检测时间。已经在汽车车身上进行了案例研究，以验证所提出方法的性能。