Noise rejection for ultrasonic sensors in mobile robot applications

The authors categorize different types of noise and discuss methods for rejecting each type of noise. They introduce a method called error eliminating rapid ultrasonic firing (EERUF). EERUF combines different noise rejection techniques and optimizes them for rapid firing. EERUF almost completely rejects crosstalk. Its unique noise rejection capability allows multiple mobile robots to collaborate in the same environment, even if their ultrasonic sensors operate at the same frequencies. For each noise category methods are described to identify and reject the resulting errors. These individual rejection measures were combined into one error rejection method which was then combined with a fast firing algorithm. The resulting combination was EERUF. The EERUF method was implemented on a mobile robot and experimental results are presented. With EERUF, a mobile robot was able to traverse an obstacle course of densely spaced, pencil-thin poles at up to 1 m/s