Dimensional measurement of hot heavy forgings is desirable to permit real-time
process control, but usually is inconvenient because of the difficulty in working with very hot
workpieces. This paper presents an approach based on Two-dimensional Laser Range Sensor
(TLRS). Firstly, the measurement system can be obtained by assembling TLRS, an axis of rotation,
and a servo motor, which rotates and scans forgings in different planes. Then, the coordinates of
points of forging's surface can be obtained in coordinate system in scanning plane. Secondly, the
origin of Measurement Coordinate System (MCS) at the centre of rotation of TLRS can be located.
According to the transformation between Sensor Coordinate System (SCS) and MCS, coordinates
of points in different SCS can be transferred into the fixed MCS. Next, the final points of forging's
surface in MCS can be obtained. Hence models of hot heavy forgings can be reconstructed by
using Triangulated Irregular Network and optimized by employing Delaunay rules. Finally,
different parameters of forgings, such as lengths and diameters, can be measured. In order to
calibrate the measurement system, a pyramid is proposed to compute the transformation matrix
between SCS and MCS based on the projective geometry theory. The new method has been
verified by experiments in both the laboratory and the forging workshop. The experimental results
indicate that it is much more practical for the real time on-site measurement of hot heavy forgings.
This research lays a desirable foundation for the further work.