Fast, Accurate Sonar-Ring System

Mobile robots often require distance to objects surrounding them for navigation tasks. The sonar ring is widely used to measure distance because it is easy to use and provides distance information all around the robot. Although accurate in range, a sonar ring has difficulty determining bearings to surrounding objects. Conventional sonar rings are slow in covering a full 360 degrees due to sequential driving of transducers for avoiding interference. In this paper, we propose a new sonar-ring sensor system for a mobile robot that can accurately measure bearing angles to objects in a single measurement. The proposed system simultaneously transmits and receives ultrasound in all directions and measures time-of-flight (TOF) differences, achieving fast, accurate measurement of points reflected around a robot. System design and implementation of the proposed sonar ring are also described and the effectiveness of the proposed system shown by experimental results.