Ultrasonic Robotic-Sensors for Exact Short Range Distance Measurement and Object Identification

Abstract

Ultrasonic Distance Sensors recognize structures in the direction of ultrasonic propagation as a sequence of echoes. This sequence is digitized and stored in a memory as an Echo Profile, which represents the p revailing situation and which can be evaluted and interpreted by a microcomputer. By using such ultrasonic sensors as Gripper R eferred Sensors the movement of a robot can be controlled in accordance with a given situation, avoiding p recise movements on predetermined paths after a preinspection. This application as an Eye in the Hand demands for rugged ultrasonic transducers with a high l ocal resolution. Our novel L2QZ-Transducers, consisting of a composite of piezoceramic and plastic material, yield a broad bandwidth and correspondingly short ultrasonic echoes by a low Q-Factor ((3) and a low acoustic impedance. With sample transducers having a center f requency of about 200 kHz a step resolution of about 1 mn was achieved directly and was improved by mathematical deconvolution by the f actor of 2 to 5.