Precision laser triangulation range sensor with double detectors for measurement on CMMs

Usual commercial laser triangulation range sensor offers a noncontact means of measuring part dimensions for use with CMMs. However, there are several factors such as surface inclination and reflection variation which must be taken into account if accurate and reliable results are to be achieved. In this paper a precision laser triangulation range sensor with double detectors is proposed. The sensor can continuously and simultaneously detect the range of displacement and the surface inclination as well as generate a tracing signal to trace the surface normal. Using the summing signal processing method, the measurement error caused by surface inclination can be partly compensated. In this paper the derivation of the relation between the displacement of the surface and the centroid shift on the detector is presented. The computer simulation and experimental results show that the proposed sensor is able to provide the means with noncontact, high speed, high accuracy for profile measurement, even though for sculptured surface measurement on CMMs.