Design and Manufacturing Engineering Department, University of Zaragoza, María de Luna, 3, E-50018, Zaragoza, Spain.
Sensors (Basel). 2011;11(1):90-110. doi: 10.3390/s110100090. Epub 2010 Dec 23.
This article discusses different non contact 3D measuring strategies and presents a model for measuring complex geometry parts, manipulated through a robot arm, using a novel vision system consisting of a laser triangulation sensor and a motorized linear stage. First, the geometric model incorporating an automatic simple module for long term stability improvement will be outlined in the article. The new method used in the automatic module allows the sensor set up, including the motorized linear stage, for the scanning avoiding external measurement devices. In the measurement model the robot is just a positioning of parts with high repeatability. Its position and orientation data are not used for the measurement and therefore it is not directly "coupled" as an active component in the model. The function of the robot is to present the various surfaces of the workpiece along the measurement range of the vision system, which is responsible for the measurement. Thus, the whole system is not affected by the robot own errors following a trajectory, except those due to the lack of static repeatability. For the indirect link between the vision system and the robot, the original model developed needs only one first piece measuring as a "zero" or master piece, known by its accurate measurement using, for example, a Coordinate Measurement Machine. The strategy proposed presents a different approach to traditional laser triangulation systems on board the robot in order to improve the measurement accuracy, and several important cues for self-recalibration are explored using only a master piece. Experimental results are also presented to demonstrate the technique and the final 3D measurement accuracy.
本文讨论了不同的非接触式 3D 测量策略，并提出了一种使用新型视觉系统（包括激光三角传感器和电动线性平台）测量通过机器人臂操作的复杂几何形状零件的模型。首先，本文将概述纳入自动长期稳定性改进简单模块的几何模型。自动模块中使用的新方法允许设置传感器，包括电动线性平台，以避免使用外部测量设备进行扫描。在测量模型中，机器人只是具有高重复性的零件的定位。它的位置和方向数据不用于测量，因此它不会直接作为模型中的主动组件“耦合”。机器人的功能是沿着视觉系统的测量范围呈现各种工件表面，视觉系统负责测量。因此，除了由于静态重复性不足导致的误差外，整个系统不受机器人自身轨迹误差的影响。对于视觉系统和机器人之间的间接联系，原始模型仅需要一个第一块测量作为“零点”或母版，使用例如坐标测量机来对母版进行准确测量。所提出的策略针对机器人上的传统激光三角测量系统提出了一种不同的方法，以提高测量精度，并使用仅一个母版探索了几个用于自动重新校准的重要线索。还介绍了实验结果以证明该技术和最终的 3D 测量精度。
