Modeling of slip for wheeled mobile robots

This paper introduces error eliminating rapid ultrasonic$nng(EERUF), a new method for firing multiple ultrasonic sensors in mobilerobot applications. EERUF allows ultrasonic sensors to fire at ratesthat are five to ten times faster than those customary in conventionalapplications. This is possible because EERUF reduces the number oferroneous readings due to ultrasonic noise by one to two orders ofmagnitude. While faster firing rates improve the reliability and robustness ofmobile robot obstacle avoidance and are necessary for safe travel athigher speed (e.g.,I > 0.3 dsec) , they introduce more ultrasonicnoise and increase the occurrence rateof crosstalk. However, EERUFalmost eliminates crosstalk, making fast firing feasible. Furthermore,ERRUF’s unique noise rejection capability allows multiple mobile robotsto collaborate in the same environment, even if their ultrasonic sensorsoperate at the same frequencies.We have implemented and tested the EERUF method on a mobilerobot and we present experimental results. With EERUF, a mobile robotwas able to traverse an obstacle course of densely spaced, pencil-thin (8mm-diameter) poles at up to 1 dsec . Manuscript received June 1, 1992; revised July 1993. This work wassupported in part by Department of Energy Grant DE-FG02-86NE37969 andin part by the Veterans Administration Grant 028085.The authors are with the University of Michigan, Departmentof MechanicalEngineering and Applied Mechanics (MEAM), Ann Arbor, MI 48109-21 I OUSA.IEEE Log Number 9403337.EERUF Error Eliminating Rapid Ultrasonic Firing.URS Ultrasonic Range Sensor.