Optimal ultrasonic sensor ring with beam overlap for high resolution obstacle detection

This paper presents an optimal ultrasonic sensor ring with beam overlap for high resolution obstacle detection of a mobile robot. It is assumed that a set of low directivity ultrasonic sensors of the same type are arranged in a circle of nonzero radius at regular spacings with their beams overlapped. First, the concept of efficient beam overlap among three adjacent ultrasonic sensors is introduced, and the structural restrictions on an overlapped ultrasonic sensor ring for efficient beam overlap are derived. Second, the effective beam width of an overlapped ultrasonic sensor ring are assessed, and the optimal design parameters of an overlapped ultrasonic sensor ring for minimal positional uncertainty are determined. Third, the high resolution obstacle detection based on the inequality relationships among three adjacent obstacle distances is proposed, and using the resulting decision table for uncertainty arc, the outline extraction in a rather complex obstacle environment is performed.