面向复杂立体石雕的机器人面扫描视点规划

Robotic Surface Scanning Viewpoint Planning for Complex 3D Stone Carving

目前,在机器人石雕环节缺少对工件表面的质量检测,无法保证后续的机器人磨抛精度,从而导致产品报废。因此,提出了一种基于截面线点云的机器人面扫描视点规划新方法,并将其应用在复杂立体石雕自动化测量中。首先,采用单因素试验和中心组合设计响应面法确定最优扫描工艺参数。其次,利用最小外接圆柱确定截面线数量,并探究截面线不同采样方式对扫描质量的影响,选取等弧长采样获得扫描视点,通过向量叉乘和分离轴理论对扫描视点进行遮挡和碰撞检测,对存在遮挡与碰撞的视点进行优化,针对扫描过程中由于频繁变换扫描方向导致扫描效率降低的问题,提出了一种生长聚类算法优化扫描方向。此外,为了保证整个扫描过程的连续性,在两相邻扫描路径之间引入旋转扫描。最后,进行了弥勒佛(260 mm×210 mm×560 mm)扫描视点规划和测量试验,结果表明,整体扫描耗时152 s,扫描完整性100%,扫描精度0.26 mm。所提方法能快速完成复杂立体石雕的三维扫描,采用规划视点扫描的模型完整性好、精度高,能够满足复杂立体石雕自动化测量要求。

Currently,the lack of quality inspection of the workpiece surface in the robotic stone carving segment does not guarantee the accuracy of subsequent robotic grinding and polishing,which leads to product scrap.Therefore,a new method of robot surface scanning viewpoint planning based on cross-sectional line point clouds is proposed and applied to the automated measurement of complex 3D stone carving.Firstly,the optimal scanning process parameters are determined using single-factor experiments and the central composite design response surface method.Secondly,the number of cross-section lines is determined by using the minimum external circular column,and the effect of different sampling methods of cross-section lines on the scanning quality is investigated,the scanning viewpoints are obtained by selecting equal arc length sampling,detected by vector fork multiplication and separation axis theory,and optimized for the viewpoints with occlusion and collision,and a growth clustering algorithm is proposed to optimize the scanning direction for the problem that the scanning efficiency is reduced due to frequent change of scanning direction in the scanning process.In addition,to ensure the continuity of the whole scanning process,rotational scanning is introduced between two adjacent scanning paths.Finally,the scanning viewpoint planning and measurement experiments of Maitreya Buddha(260 mm×210 mm×560 mm)are carried out.The results show that the overall scanning time is 152 s,the scanning integrity is 100%,and the scanning accuracy is 0.26 mm.The proposed method can quickly complete the 3D scanning of complex three-dimensional stone sculptures,and the model scanned using the planned viewpoint has good integrity and high accuracy,which can meet the automated measurement requirements of complex three-dimensional stone sculptures.