The Calibration And Error Analysis Of The LED Artificial Sky Simulating And Measuring System

Natural light is an indispensable part of people's life.Natural light is an inexhaustible renewable energy with the characteristics of economy and environmental protection.With the progress of society,the concept of sustainable development has been widely recognized,and the application of natural light in architecture has attracted much attention.Fully and reasonably utilizing natural light has become one of the important technical methods in the field of building skills,so the study of natural lighting environment is very important.In 2004,CIE TC3-15 Sky Brightness Distribution Model was formally published as CIE Standard.Based on a large number of outdoor sky observation data,15 kinds of Sky Brightness Distribution Models were summarized by means of mathematical statistics analysis.At present,the methods of simulating sky brightness distribution model include computer simulation and artificial sky simulation measurement system.Computer simulation has limitations,and repeatable experiments are needed to verify the accuracy of simulation.The artificial sky simulation measurement system makes up for this deficiency in experimental verification.With the development of LED technology and the maturity of optical parameter control technology,it provides a basis for simulating the fast changing natural light environment,and makes it possible for artificial sky to accurately simulate the brightness distribution of CIE sky.Therefore,it is possible to construct a repeatable and stable natural light environment by using LED light source to construct artificial dome simulation measurement system.At the end of 2016,Harbin University of Technology built a simulation measurement system for artificial sky of LED light source with a diameter of 15 meters.The calibration of artificial sky system of LED light source has become a new research topic.This paper takes the artificial sky simulation test system of LED light source constructed by the Cold Architecture Science and Research Center of Harbin University of Technology as the research object.Firstly,the spherical center of the artificial dome is measured and calculated,the error is analyzed and the confidence is given.Taking the spherical center as the reference point,the parameters of the artificial sky simulation test system for LED light source are calibrated.By calibrating the parameters,adjusting the LED light source and simulating the CIE15 sky model,15 kinds of simulated sky models were measured,and the simulation system error was analyzed.Secondly,the relationship between spatial scale of artificial dome and field uniformity is measured and analyzed.By changing the height of the experimental platform in the artificial sky,the uniformity of the light field on the altitude plane of the experimental platform is measured and analyzed,and the uniformity analysis of the size of the building model under the spatial scale of the CIE15 sky model is given.Finally,the influence of the position distribution of the LED light source on the field uniformity is discussed.By changing the distance between the measuring surface and the LED light source,the distance between the LED light source and the number of the LED light source lamps,the influence of the position distribution of the LED light source on the field uniformity is analyzed,which provides data reference for the future design and construction of the artificial sky measurement system of the LED light source.