A SYNTHETIC BEAM SONAR SYSTEM FOR MOBILE ROBOTS AND TELEOPERATORS

THE POTENTIAL OF ULTRASONIC RANGING HAS BEEN RECOGNIZED BY MOST MOBILE ROBOTICS RESEARCHERS. VARIOUS NARROW BEAM SYSTEMS) WERE USED ON EARLY MOBILE ROBOT TEST BEDS. THE SHORTCOMINGS OF THESE SYSTEMS INCLUDE SLOW ACQUISITION SPEEDS, LOST SIGNALS FROM SPECULAR REFLECTIONS, AND INADEQUATE IMMUNITY FROM NOISE. THE FIRST COMMERCIALLY AVAILABLE BROAD BEAM ULTRASONIC SYSTEM FOR MOBILE ROBOTS WASRECENTLY INTRODUCED. INSTEAD OF NARROW BEAMS EMANATING RADIALLY, THIS BASIC SYSTEM USES TWO FORWARD-LOOKING, BROAD BEAM TRANSDUCERS LOCATED ON OPPOSITE SIDES OF THE FRONT OF THE VEHICLE. BY DIGITIZING THE RECEIVED ECHOS AND APPLYING DIGITAL SIGNAL PROCESSING, THE SYSTEM HAS OVERCOME MANY OF THE PROBLEMS INHERENT IN EARLIER SYSTEMS. THE CURRENT SYSTEM CAN, HOWEVER, ONLY DETECT THE RANGE AND DIRECTION TO THE NEAREST OBJECT. IN THIS PROJECT, THE STEREOSCOPIC DATA WILL BE FURTHER PROCESSED TO PROVIDE A TWO-DIMENSIONAL IMAGE OF THE ENVIRONMENT IN FRONT OF THE VEHICLE. SINCE MANY SYNTHETIC BEAMS COULD BE GENERATED BY THE INFORMATION FROM ONLY A FEW ACTUAL "PINGS", THE SYSTEM WILL OPERATE MUCH FASTER THAN CONVENTIONAL BEAM SYSTEMS.