A design of onboard multi-channel sonar signal processing system for autonomous mobile robots

In the last several years, mobile robot systems that achieve complicated tasks have been developed. When a robot works in a cramped workspace, the robot has to detect arrangement of circumambient obstacles in order to avoid collisions. We considered a simple distance estimation algorithm for ultrasonic sonar. This algorithm was able to estimate distance with approximately 13 mm of errors out of 1300 mm using conventional 40 kHz transducer in confirmation experiments. We also attempt stereo reception using two ultrasonic microphones. The stereo reception sonar was able to detect direction with approximately 4.2 degrees of error in preparatory experiments. In order to install small mobile robots and to detect circumambient obstacles, we designed a multi-channel sonar signal processing system using a high-performance embedded microcontroller. This paper describes our idea of the distance estimation algorithm of ultrasonic sonar and a design of signal processing system using a high-performance microcontroller.