A Study on Autonomic High Speed Measurement of a Three Dimensional Shape by Using a Non-Contact Sensor for Detecting an Inclination Angle and a Gap Distance (1st Report): —Design of an element for the Sensor with Multi-beam Projection—

The study is on autonomic high speed measurement of a three dimensional shape by using a non-contact sensor which can continuously and simultaneously detect the normal direction and the position of a measured point. This paper describes the system architecture and a design of the sensor. In order to design the sensor, the principle for detecting a normal direction and a position by reflected light of a beam projected on a measured point is clarified. According to the principle, a structure of the sensor element which has an emitting optical fiber with a graded-index lens and eight receiving optical fibers is determined. Also, computer simulations are performed to make the performance of the sensor element clear. In the simulations, a model-equation which expresses ray-intensity of the projected beam is derived, and reflected light of the beam is modeled by a diffuse component and a specular component. From the simulation-results, it became clear that the sensor element can detect a normal direction in the range from -45.0° to 45.0° and detect a position in the range from 2.7 mm to 6.0 mm for a diffuse surface. For a specular surface, the range of a detected normal direction is restricted from -7.5° to 7.5°.