Modeling the Geometry of the Laser Distance Sensor

Abstract

The paper presents an analysis and design considerations for a non-contact distance sensor. The sensor operates on the triangulation principle and utilizes a low power laser beam as a source of light First, the paper describes the major components of the sensor and itS principles of operation. Also, additional electronic components, that are necessary for sensor operations, are briefly presented. These include a laser diode driver and a conditioning circuit for a position sensitive detector (PSD). Next, a model of the geometry for the distance sensing device is presented. Analysis of the sensor model results in a detailed description of the effects of the sensor's geometrical parameters on the performance of the sensor. In particular, non-linearity of its characteristics is analyzed in detail, and some design hints on how to avoid it are presented. Furthermore, major trade-offs, which must be considered while selecting design parameters of the laser sensing device, are described. Finally, the paper gives examples of possible applications of a non-contact laser distance sensor.