Laser line scanners: the eyes of your robot

The sensors act as the ‘eyes’ of the robot and are used in a variety of applications from gap measurement in car interiors and automatic weld inspection systems, to industrial pick-and-place systems, says Chris Jones, Managing Director of Micro-Epsilon UK.

As well as inspecting one-dimensional parameters, there is now an increasing
need for multi-dimensional quality control in industrial production. Laser profile sensors (laser line scanners) are designed to carry out complex 2D/3D measurement tasks in robotics and other automated, high speed production environments, where the sensors are increasingly used to measure profiles and contours.

The operating principle of a laser line scanner is
based on the laser triangulation technique for two-dimensional profile detection. They detect, measure and evaluate the profiles on different object surfaces. By using special lenses, a laser beam is enlarged to form a static laser line instead of a point and is projected onto the target surface. An optical system projects the diffusely
reflected light of this laser line onto a highly sensitive sensor matrix. In addition to distance information (z-axis), the controller also uses this camera image to calculate the position along the laser line (x-axis). These measured values are then output in a two-dimensional coordinate system that is fixed with respect to the
sensor. In the case of moving objects or a traversing sensor, it is therefore possible to obtain 3D measurement values. Laser line scanners are equipped with an integrated, highly sensitive receiving matrix that enables measurements on almost all industrial materials, largely independent of the surface reflection.

Read the full article in the February issue of DPA