A method for qualifying high density data acquisition systems for free form metrology

摘要

The Vehicle Perception Safety Research Team of the Ford Manufacturing & Vehicle Design Research Laboratory has developed artifacts, procedures and data analysis techniques to assist in evaluating systems used for the high-speed collection of geometric data. These systems are usually comprised of a non-contact sensor and a means of positioning the sensor relative to the part being inspected. They are usually used to collect data from sculptured or "free form" surfaces for reverse engineering or for applications in the emerging field of free form metroogy. The evaluation procedure consists of acquiring data from three ceramic balls nominally 44.45 mm in diameter held by depressions in a flat plate. The data are then first analyzed using least square techniques to obtain observed radii of the balls and the location of their centers. Then free form metrology techniques are used to compare the data from each ball to an ideal sphere of the observed radius and center location. By combining the observed location and radii with a high resolution graphical representation of the quality of fit between the data and an ideal sphere, a good assessment of the system's capability for collection of data for reverse engineering or for free form metrology is obtained. At the same time the technique graphically reveals any troublesome systematic or shape-related sources of error.