Hindawi Publishing Corporation International Journal of Photoenergy Volume 2013, Article ID 754549, 7 pages http://dx.doi.org/10.1155/2013/754549 Research Article Design and Manufacturing of a High-Precision Sun Tracking System Based on Image Processing Kianoosh Azizi and Ali Ghaffari Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Pardis Avenue, Molla-Sadra Avenue, Vanak Sq., P.O. Box 19395-1999, Tehran 19991 43344, Iran Correspondence should be addressed to Kianoosh Azizi; kianooshazizi@gmail.com Received 30 May 2013; Revised 5 August 2013; Accepted 5 August 2013 Academic Editor: Mohammad A. Behnajady Copyright © 2013 K. Azizi and A. Ghafari. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Concentration solar arrays require greater solar tracking precision than conventional photovoltaic arrays. his paper presents a high precision low cost dual axis sun tracking system based on image processing for concentration photovoltaic applications. An imaging device is designed according to the principle of pinhole imaging, making sun rays to be received on a screen through pinhole and to be a sun spot. he location of the spot is used to adjust the orientation of the solar panel. A fuzzy logic controller is developed to achieve this goal. A prototype was built, and experimental results have proven the good performance of the proposed system and low error of tracking. he operation of this system is independent of geographical location, initial calibration, and periodical regulations. 1. Introduction Renewable energies are considered as a great source of energy during the last two decades. As an important source of alternative energy, the solar has unlimited reserves, has wide- spread existence, is pollution-free, and so forth. It is shown that optimum of solar energy is obtained when sun rays are incident normally on the transforming part of solar systems, such as solar thermal collectors, solar cells, and other solar equipments. Among various types of solar cells, the appli- cation of high concentration solar cells allows a signiicant increase in the amount of energy collected by solar arrays per area unit. However, the performance of solar cells with concentrators decreases drastically if the sun pointing error is greater than a small value and, therefore, a low tracking error must be achieved for this kind of solar photovoltaic arrays (PV) compared with conventional PV arrays [1]. Several kind of solar tracking systems are proposed in the literature; one can classify them according to their degrees of freedom (DoFs) and/or control strategy. Regarding DoF, there are three main types of trackers [2]: ixed devices, single-axis trackers (see [3]), and dual-axis trackers (see [4]). It is shown that the annual gain in energy production of the dual and single-axis trackers is 1.5 and 1.40–1.45, respectively, compared with the nontracking systems [1]. Regarding con- trol strategy, three main types of solar trackers exist [5]: pas- sive, open-loop, and closed-loop controlled trackers. he pas- sive trackers have no electronic sensors or actuators [6]. he open-loop ones have no sensors too but use microprocessor and are based on mathematical formulae to predict the sun’s position [7, 8]. he third kind of trackers use the information of electro-optic sensors for estimating the location of the sun [5, 9]. he open-loop trackers are dependent on geographical location and the start time situation of the system, while closed-loop systems do not have these disadvantages. An open-loop type of controller does not observe the output of the processes that it is controlling. Consequently, an open-loop system cannot correct any errors so that it could make and may not compensate for disturbances in the system. he system is simpler and cheaper than the closed- loop type of sun tracking systems [10]. In open-loop mode, the computer or a processor calculates the sun’s position from formulae or algorithms using its time/date and geographical information to send signals to the electromotor. However, in some cases many sensors are used to identify speciic positions [11]. he systems proposed in [12, 13] are in this category.