On dual ultrasound sensor technique for unmanned vehicles

✍ Scribed by Wen C. Lin; Huey R. Tsui

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 1005 KB
• Volume: 1
• Category: Article
• ISSN: 0926-5805
• DOI: 10.1016/0926-5805(92)90005-5

✦ Synopsis

Ultrasound ranging devices have been widely used in unmanned vehicles or autonomous mobile robots because of their cost-effectiveness and reliability. They have been widely used for detecting obstacles for collision avoidance, and path planning. However, due to the properties of the ultrasound devices, they suffer a few important drawbacks for these applications. First, they detect only objects whose surface is normal with respect to the traveling direction of the sound beam generated, i.e., they do not "see" obstacles whose surfaces are oriented more than _+ 12 ° off normal. Second, they do not provide any information on the size of the obstacle even when the surface is normal with respect to the sound beam. In this paper, we describe a technique by which a system can estimate the size of objects of different orientations. This technique utilizes a pair of Polaroid ultrasonic ranging units mounted on a rotating shaft to scan the surrounding environment. The data are then fed into an IBM-PC/XT and processed by a novel algorithm. Experimental results show that the system can estimate the size of an object at different orientations. It can detect an obstacle and determine if the obstacle is moving or stationary. With this property, the system can plot its environmental setting, and the perimeter of an object, which is essential information for any unmanned or autonomous vehicles. The algorithm is first simulated on the IBM-PC/XT using the raw data collected with the dual ultrasound device based system. The algorithm is then verified experimentally with the "real-world" environment.