太阳自动跟踪机构的设计和位姿分析

Design and positional posture analysis of parallel sun auto-tracking mechanism

设计了一种新型三自由度并联跟踪机构,以使太阳能板全方位地跟踪太阳并最大限度地输出有效发电量。采用三角平台上的万向节使太阳能板的大部分重量传递到支架上,通过3条细钢丝绳的协调动作使太阳能板的姿态发生变化,达到跟踪机构驱动电机耗能小,输出有效发电量多的目的。利用坐标变换理论建立了该三自由度并联跟踪机构的位置正解方程,然后用牛顿迭代法数值求解正解方程组;最后,依据空间投影理论对该并联跟踪机构的空间位姿进行实测分析,并对设计的跟踪机构与传统二轴跟踪机构进行驱动耗能对比实验。结果表明:本文建立的位置正解方程与实测结果的趋势基本相同,输出位姿空间角α、β和距离zB的平均误差分别为1.8%、2.6%、0.84%,满足跟踪机构的误差要求,设计的跟踪机构的耗电量约为传统二轴跟踪机构的25%。

A new type of 3-DOF sun parallel tracker was designed to track the sun all-around and to maximize its effective output powers.By using the cardan joint on a triangular platform to transfer the most of the weights of solar panels to the stand and to change the positional posture of the solar panels in all direction through three thin steel ropes,the track mechanism could reduce the electrical power consumption of own motor and could generate more efficient powers.Firstly,the forward position equations of the 3-DOF parallel tracker were established based on the theory of coordinate transformation.And then the forward position equations were solved by Newton＇s iterative method numerically.Finally,the space positional posture was measured and analyzed with the theory of the space parallel projection to verify the accuracy of the forward position equations.A driven energy experiment was performed to contrast the power consumption between the designed mechanism and a traditional two-axis tracker.The experimental results show that the established forward position equations and measured results have the same trend basically,and the average errors of output positional postures for space angles α,β,and distance zB are 1.8%,2.6%,0.84%,respectively.This accuracy can meet the requirements of the tracking mechanism for errors.Moreover,the power consumption of the designed tracking mechanism is about 25% that of the traditional two-axis tracker.