| With the progress of science and technology, the robot industry is booming. Service robots act an important role in the robot industry, they provide services to the human and make people free from hard works, increase the happiness of people’s life,effectively alleviate the pressure of the society. So, it is particularly important to study the service robots. Positioning and obstacle avoidance technology is the first requirement of service robots to provide services, the purpose of this paper is to find a practical approach for orientation and local obstacle avoidance, and to apply it to practice.On the positioning method of the robot, considering the indoor environment in this topic, we use an UWB(Ultra Wide band) UHF positioning system.Using a navigation beacon positioning method, to establish three base stations in the indoor environment. The robot acts as the beacon source,using the localization algorithm, we obtain the accurate position of the robot by calculating the relative distance between the base station and the robot.Using laser sensor for obstacle detection, on the obstacle avoidance strategy, we choose the VFH * local obstacle avoidance algorithm. Due to the limitations of reactive-style obstacle avoidance strategy, it is unavoidable for the robot to get into a "trap"(U-shaped obstacles, for example) in the process of obstacle avoidance. This paper take the U-shaped obstacles for example,analysis the reason why the robot gets into the "trap",illustrates the escape method, proposes an improved VFH * algorithm by which the robot can quickly escape from the trap.Finally,we verify the effectiveness of the navigation beacon positioning method and the improved VFH * algorithm on the experimental platform,conduct an escape experiment aiming at the U-shaped obstacles,get the result which proved the accuracy of navigation beacon positioning method, at the same time the improved VFH * algorithm is proved to be able to help the robot to escape from the trap. |
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