Ultrasonic visibility tests and estimation of specular target plane orientation through a robotic scanning

Abstract

In this paper, the authors present an ultrasonic scanner of own design consisting of a smart robotic arm which is accurately programmed to let an ultrasonic sensor track a linear path. They use both a narrow and a wide beam sensor with a view to evaluating the relating regions of detection. After acquiring and processing the ultrasonic echo signals reflected from a target panel, the realized mechatronics system permits to obtain a distance measure for each end-effector position. The set of distance values is connected to the scan, that is a plot obtained by displaying dots at the appropriate range along the direction perpendicular to the followed path. In consequence of physical considerations, a geometrical model of the conical region of detection was confirmed and several tests were carried out in order to compare predicted data with experimental ones. This comparison also permitted to appreciate the visibility angle of each sensor and to verify the obstacle ability to reflect back the acoustic energy taking the eventual effect of lateral lobes into consideration. Moreover, some tests were conducted by spreading ultrasonic waves toward an inclined plane and the scans were opportunely regarded to estimate the panel orientation. This recently introduced approach was based on line fitting and it could be applied to wall-following problems in robotics.