System for Mapping an Estimate Zone of Actuation of Ultrasonic Sensors

Abstract

It is possible to see a considerable growth in the application of sensors in processes and products, seeking for automation, quality gain or to increase safety. Among the vast array of sensors, one of the most used is the ultrasonic sensor. It works based on a measurement of the time spent by a sound wave that travels from a transmitter transducer, reflects on the surface of an object and returns to a detector, commonly used for determining distance. Despite being a well-known principle, it is not trivial to determine the total coverage space of the ultrasonic sensor. Companies that produce ultrasonic sensors, generally, specify the actuation distance or the range of the sensor in its datasheet. However, the information about the working space of the sensors is not presented, only a linear distance or a planar region of operation is shown. Considering projects where the 3D zone of actuation of the sensor is essential, this paper presents a system capable of measuring this zone for ultrasonic sensors, thus ensuring greater reliability in their application in situations that requires security. To define the region where the ultrasonic waves can detect an object, a system was developed, allowing the mapping of the three-dimensional zone. The system consists of a metal structure, on which a robot, built with LEGO©'s kit, positioning an object that can be captured by the ultrasonic sensor. The object moves in three mutually perpendicular axes, making a right prism with a rectangular base (1m x 1m x 4m). The ultrasonic sensor is positioned in the center of the first plane and captures the object moving in the structure space. After the mapping it was possible to generate a graphic with the estimate zone of activity of the sensor, which helped to define the beam of the sensor, contributing in the identification of the opening angle and maximum range of detection. This method can be also performed for evaluation of sensors applied in vehicular safety systems, identifying the safe zone of operation.