Shaping the detection lobe of ultrasonic ranging devices

The detection lobe or radiation area of an ultrasonic ranging device is of primary importance in almost any application of such measuring systems, but in some cases the form of the lobe makes its use in real systems difficult or even impossible. The use of focusing arrays of sensors is difficult because of the large size of the transducers in air, the complexity of the processing devices and the slowness of the measuring process. In this paper we present a new way of conforming the operation field of an ultrasonic sensor that allows almost any arbitrary form to be fixed within the range of the sensor. The application of the system is studied in a sensor for blind people and in an obstacle detection sensor for mobile robots.