Dimensional measurements of a gray-iron object using a robot and a laser displacement sensor

This paper presents a system for noncontact dimensional measurement of a gray-iron grate by use of a laser dot triangulation displacement sensor and an industrial SCARA robot. A special kernel driver and an associated dynamic link library were written for this system, enabling a higher sampling rate of the robot world coordinate positions and of the laser measurements. For repair of the scan data and calculation of the coordinates of deburring points, another program was written, where a unique approach of polynomial approximation to the profile was developed. To determine the accuracy of the robot measurement system, a number of comparative measurements were performed on a reference cube with a coordinate-measuring machine. Comparative measurements on real gray-iron grates were also done. The results show that dimensional measurements on a grate, at 88 points, can be performed within 45 s and with ±0.3mm accuracy, which proved to be sufficient for robot deburring of gray-iron grates.