Speed control of a sonar-based mobile robot determining sensing and action strategy simultaneously

Abstract

Today, the ultrasonic TOF (time-of-flight) ranging system is the most common sensing system employed in indoor mobile robotic systems, primarily due to the easy availability of low-cost systems, their compact size, simple circuits, and their ease in interfacing with computers. TOF ranging systems measure the round-trip time required for a pulse of emitted energy to travel to a reflecting object and then echo back to a receiver. However, ultrasonic TOF ranging systems tend to neglect infinitesimal reflected waves below the threshold level. We have proposed a new approach to utilize the infinitesimal reflected waves by integrating the reflected waves. This is implemented using a transducer with a scanning system, and has a great ability of obtaining the travelable area for a robot in environments in which the distance cannot be precisely measured. The proposed system is constructed in a simple manner so as to improve the utility value of the sonar. This paper introduces the speed control strategy under uncertainty of sensor information. By considering the uncertainty of sensor information, we change the action strategy. By changing the action strategy, sensor information which is obtained by the robot changes at the same time. By using this relationship, we construct the robust robot system. The validity of the proposed method is investigated by applying this method to an autonomous mobile robot in various environments such as one with multiple obstacles, at the end of the hall, and so on.