Tracking of a moving object using ultrasonic sensors based on a virtual ultrasonic image

For a mobile robot to follow a moving target, the mobile robot should have the capability of first detecting the target and then measuring its position and velocity. This paper proposes a new solution for this problem, using the virtual ultrasonic image which is simply constructed by accumulating the returned ultrasonic signal along the time axis for a certain number of measurement periods. In the virtual ultrasonic image, the slope of the trajectory of an object represents the relative speed of the object with reference to the mobile robot and a static obstacle has a trajectory whose slope is greater than a certain threshold. The mobile robot implemented for resting the performance of the proposed algorithm has shown that it follows a moving target successfully in various working environments. (C) 2001 Elsevier Science B.V. All rights reserved.