构造了可自动切换工作模式的智能太阳跟踪器以提高其在多种气象条件下的工作性能和运行可靠性.研究了太阳跟踪器的工作模式选择问题,提出了基于图像信息的工作模式切换方法.提出的太阳跟踪器具有开环和闭环两种工作模式,由成像单元、转台、步进电机、单片机、上位机等模块构成;其闭环工作模式采用了视觉伺服控制方法,开环工作模式则采用了天文跟踪方法;由天文历法来计算太阳在天空中的位置.系统由成像单元抓取天空图像,利用图像处理的方法来分析当前的天气条件或外界环境,最后系统选择并且进人合适的工作模式.太阳跟踪实验中,系统俯仰角和方位角的太阳平均指向偏差分别为0.186 5°和0.167 9°.太阳跟踪实验表明,该跟踪器运行稳定可靠,能在较复杂的气象条件下工作.%A solar tracker with intelligent switching ability of working modes is constructed to improve its performance and reliability under several weather conditions. How to choose a proper work mode of the solar tracker is investigated, and the switching method of working mode for the solar tracker is also proposed. The solar tracker has two working modes, open loop mode and closed loop one, and it consists of an imaging unit,a turntable, steppers,the subsystem of micro control unit,a computer and so on. A visual servo scheme is employed for the closed loop mode, while astronomy theory is used for the open loop mode. Moreover, the sun position in the sky is obtained by astronomic algorithms in the case of open loop. The system captures the sky image through an imaging unit, and analyzes weather conditions and external environments through image processing. In experiments,the average tracking error is 0.186 5°for the zenith angle and 0.167 9° for the azimuth angle. The solar tracking experiments indicate that the solar tracker operates reliably, and is able to work under complex weather conditions.
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