We developed the simple optical proximity sensor based on measuring the phase shift of modulated reflex light from the object. It can measure the distance and the inclination angle of the object as well without being affected by the reflection factor. Basic elements of the proposed sensor consist of light sources and an optical detector. In case of distance measurement, two light sources are located asymmetrically to the optical detector, and driven by 90 degree phase shifted signal (sine or cosine signal). The distance can be obtained as the function of the phase angle of reflex light signal. In case of inclination angle measurement, two light sources are located symmetrically and then the inclination angle can be measured as the phase angle of reflex light. This sensor can be applied to three dimensional surface tracing control and obstacle avoidance control of the robot manipulator.
SICE Awards for Outstanding Paper in 1983.