三伸缩杆驱动的光伏板视日追踪系统设计与研究

视日追踪系统能够显著地提高光伏板接受太阳能的效率。相较于串联式，并联式视日追踪系统以其追踪精度高、功耗小和耗材少等优点在太阳能追踪中具有很大的应用潜力，但相关研究尚属起步阶段且并不能满足实际需求。基于3-RPS并联机构，提出了一种新型三伸缩杆驱动的光伏板视日追踪系统。其中，三根伸缩杆结构相同，且呈正三角形布置；每根伸缩杆的上端通过复合铰链与光伏板相连，下端通过转动铰链与基座相连；通过改变三根伸缩杆的长短驱动光伏板运动，实现对太阳的实时追踪。首先，结合太阳运动规律和3-RPS的机构性质，根据空间几何学，建立了追日过程中的相关数学模型。在此基础上，针对特定的追踪地点、日期和机构尺寸，对系统分别在夏至日和冬至日当天进行了仿真分析。进而，针对每条支链所需伸缩杆节数过多的问题，提出了动平台质心高度可动的控制策略。对于目前商业化球铰转动范围不足的问题，采用虎克铰链加转动铰链组成的复合铰链来代替球铰的结构方案，同时，得到了复合铰链绕其各转动轴线的转动角度。然后，由于追日过程是一个缓慢的过程，通过建立系统的瞬时静力学模型，仿真得到了系统所需的驱动力和驱动功率，最大驱动力为164.65N，总的最大驱动功率为2.94e-3W。最后，实施了系统的追日实验，验证了理论和仿真分析的正确性，同时得到了系统的追踪精度在±0.4°以内。

Design and Research of Three-extensible-rod Solar Tracking Drive System for Photovoltaic Panels

A solar tracking drive system can significantly improve the efficiency of photovoltaic panels for receiving solar energy. Compared with series-type, parallel-type solar tracking drive systems have great application potential in solar tacking with its high tracking accuracy, low power consumption and material loss. However, relative research is still at the beginning stage and can not meet the actual demand. Therefore, based on 3-RPS parallel mechanism, a novel three-extensible-rod solar tracking drive system for photovoltaic panels was proposed. Three extensible rods had the same structure and were arranged as an equilateral triangle. The upper end of each extensible rod was connected to the photoltaic panel by a compound hinge, and the lower end was connected to the base platform by a rotary hinge. The photovoltaic panel could be driven by changing the lengths of three extensible rods, and then the real-time solar tracking could be realized. Firstly, based on the law of solar motion and the characteristics of 3-RPS parallel mechanism, the relative mathematical models of sun tracking were established by the knowledge of space geometry. On the basis of this, for given tracking location, date and mechanism dimensions, the system was analyzed by simulation on the Summer Solstice and Winter Solstice, respectively. For the problem that the section number of each extensible rod was too much, a new control strategy of the highly movable centroid of the mobile platform was proposed. For the problem that the rotation range of the commercial spherical hinge is insufficient, a structural scheme of the compound hinge with Hook and rotation hinge to replace the spherical hinge was adopted. Moreover, the rotation angle of the compound hinge around each axis was obtained. Then, as the process of tracking the sun is slow, the instantaneous static model of the system was established, and the driving force and driving power of the system were obtained. The maximum driving force is 164.65N and the total driving power is 2.94e-3W. Finally, a solar tracking experiment of the system was carried out. The experimental results verify the theory and simulation analysis, and the tracking precision of the system is no more than ±0.4°.