| As one of the key applications of wireless sensor network (WSN), positioning and tracking has raised the attention of research institutions. The mobile robots have the ability of interacting with the environment actively. On many occasions, mobile robots are able to replace the role of human to automatically complete some daily and dangerous tasks. It has been hot in the area of studying the combination of WSN and robot, especially in the technique of positioning and tracking robot based on WSN. According to the practical demands of the mobile robot in precise positioning and tracking indoor, this thesis designed a high-quality and high-accuracy indoor positioning and tracking system based on WSN.Compare with the tracking effect on the mobile-target tracking in the passive TDOA-indoor-tracking system, the thesis designed an actively positioning and tracking indoor system, which is composed the target-nodes, the beaconing nodes, the sink nodes and the coordinate-calculating computer. The system measures the distance through the time difference between FR signals and ultrasonic signals both sent by target-nodes, and then calculates the position of the target-nodes by Maximum Likelihood Estimation method. According to the problem of a number of data transmission in a short time from target nodes to sink nodes, a kind of time-share transmission method based on beaconing nodes is designed, which is much higher-quality,and the cooperated accuracy among system nodes even achieve millimeter degree. The measure precision can come to1cm after system error are analysed by experiment,the spreading speed of ultrasonic is compensated by temperature sensor and then the system error are calibrated by experiment.On the basis of indoor-positioning-system, This thesis also designs the mobile robot system consisting of six-wheeled mobile robot, ZigBee WSN, and PC-robot-control-software. The mobile robot employs the ARM processor-STM32(Cortex-M3the core) as the kernel controller, apply μC/OS-Ⅱ system to manage the various functions of the robot and makes the system operate stably and reliably. Based on the design of Zigbee-WSN, the interacting with the data of the tracking system can be realized and the problem of wireless signals’real-time transportation in complex indoor environment can be solved. In addition, the monitoring software of PC-robot has been designed based on.NET platform and can realise the moving control and the tracking and monitoring position of the robot.In the aspect of the deployment on beaconing nodes, the simulating experiment can obtain the best deployment of the square and the hexagon and the mass deployment-strategy can be designed based on the ZigBee network. The position of the target nodes can be calculated and be displayed by positioning demonstrating soft based on.NET. In the aspect of the theory algorithm, Kalman Filter algorithm taken can realize tracking the target of the mobile robot in high accuracy.The designed positioning and tracking system in this thesis has the features of small size, high accuracy, high EFT, low power, less mount in calculating and so on. The system error is less than5cm and the highest positioning frequency is20Hz at most through the tests. This system is superior to the similar system in the world in many index of the performances and can realize the tracking of mobile robot in high accuracy. |
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