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ABSTRACT
This paper discusses the implementation of an inverted triangle tri-sonar sensing configuration to detect and avoid collision with obstacles in a structured or unstructured specular indoor environment.
The technique of sonar sensing that overcomes the problem of conventional ultrasonic ranging by providing the direction of the reflecting point is used. Conventional ultrasonic sensors do not provide the reflecting point accurately, therefore inconvenient to use in detecting obstacles in an environment where accuracy in range measurement is required.
We have therefore, considered the beam width characteristics of the implemented sonar sensor to position the sonar sensors on the front panel of the robot used in the study.
The choice of range data for the algorithm has been done in order to minimize cross echoes from neighboring sonar sensors that may be within the environment. In addition, the sensing technique allows getting more information from a single measurement by sensing several features at once.
Our results show that this technique increases speed and precision of environment mapping for obstacle avoidance and navigation.
Keywords: Sound Navigation and Ranging (SONAR), ultrasonic ranging, beam width, reflecting point, obstacle avoidance, specular characteristics
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1. INTRODUCTION
Ultrasound time of flight (TOF) sensors normally used in mobile robot applications such as distance measurement, environment perception and robot navigation [2, 3] have been around for a while. In many applications like environment perception or robot navigation, ultrasonic sensors have been considered to be unreliable and inaccurate, due to the wide opening angle that introduces a high angular uncertainty.
On the other hand ultrasound sensors are simple in construction and use, mechanically robust, and provide a cost-effective process for environment perception. The widely used Polaroid device is inexpensive, easy to integrate into other systems and has found wide use in robotic applications. Due to the importance of ultrasound sensors, research has focused on the ultrasound rangefinder data interpretation and improvement [4]. Regarding data interpretation, several physical simulation models [2] and experimental based models derived from data collection [5, 3] have been addressed.
An external sensor is very important for a mobile robot to recognize its environment and its own position. In particular, the range sensor, which can measure the distance to objects, is also useful in recognizing the physical...