Omnidirectional Ultrasonic Localization for Mobile Robots

To solve the detection angle limitation of conventional ultrasonic sensors, we propose a localization system based on omnidirectional ultrasonic sensing by using a reflection cone to generate ultrasonic beams with 360° propagation. The architecture of the proposed localization system includes four ultrasonic receivers deployed around a square measuring environment and a mobile robot carrying an integrated omnidirectional ultrasonic module as a transmitter. When the ultrasonic receivers receive ultrasonic signals from the integrated omnidirectional ultrasonic module, distance measurements between the transmitter and the receiver can be obtained by time-of-flight calculation, which are sequentially transferred to a remote PC via a Zigbee wireless network. Using the distance measurements collected from the receivers, the coordinates of the mobile robot can be determined by using the established dual-circle localization method. Experimental results have shown satisfactory accuracy in determining the coordinates of the mobile robot via the proposed localization system.