Research On Earth-sun Movement Modeling And Its Application Based On Theory Of Mechanism

The applied research on solar direction is always a significant topic. It is not only widely concerned in field of new energy, but also an essential problem in field of celestial navigation. As an ancient celestial navigation technology, positioning with solar direction has advantages of strong concealment, no electromagnetic interference, etc. Presently, related sun researches mainly focus on overcoming technology problems, such as improvement of devices' precision. Principle of algorithms is less concerned. Current solar direction algorithm is based on spherical trigonometry, which is hard to understand.In this paper, problems of current solar direction application are summarized according to domestic and foreign works. Based on which, research topic is herein proposed. Firstly, theory of mechanisms is applied to the earth-sun movement. An imaginary earth-sun movement mechanism C1R2P2 is put forward to reproduce movement of any earth's location around sun with five kinematic pairs visually. Secondly, according to proposed series mechanism C1R2P2, motion model is built up. The forward kinematics analysis with Denavit-Hartenberg method and product of exponential formula(POE) is used to establish time-space relationship equation of earth's location to sun's center in motion space. The equation is applied to solar direction calculation to achieve a new solar direction algorithm by local time and latitude. Then, a further research on proposed motion model of series mechanism C1R2P2 is performed with inverse kinematics method. A calculation method of latitude and longitude by Greenwich Mean Time(GMT) and solar direction is obtained for single celestial positioning. Finally, application research of presented algorithms is carried out. Man-machine interfaces for the presented algorithms are designed respectively into a solar direction calculator and a latitude-longitude calculator with the GUI module in MATLAB, by which automatic calculation of single point data can be realized. An Android solar angle application and an IOS camera positioning application are developed to test feasibility of proposed algorithms. Since astronomy algorithms are difficult to be implemented in solar tracking system, a conceptual design scheme is proposed to integrate proposed solar direction algorithm into a solar tracking system.