Zheliazkov Y. System of adaptive lighting based on determination of human circadian rhythms

Dissertation is dedicated to the development of an adaptive lighting system, which, based on data on human physiological parameters and lighting indoor parameters, performs the function of regulating and maintaining comfortable conditions for a person's stay in the room by adapting to their circadian rhythms, which avoids deterioration of health. Adaptation of light to human circadian rhythms involves taking into account physiological data and microclimatic parameters of the room in which a person is staying. Registration of physiological signals has both advantages and disadvantages: advantage is the availability of additional information and to adjust the lighting mode to a specific user; disadvantage is the constructive complexity of signal registration. When implementing adaptive lighting, it is also necessary to take into account the geometric and light characteristics of the room. For most situations the main requirements for adaptive lighting systems are: 1) a colour temperature that matches the time of day and human physiological parameters; 2) no luminous flux fluctuations; 3) energy parameters - the dependence of radiation energy on the radiation wavelength - must be consistent with the colour temperature at specific times of the day. The main task of work is to study the effect of different types of light on human circadian rhythms and to develop a system that can adapt to personal physiological characteristics and microclimatic parameters at a particular time, taking into account geographic location. In practice, systems are using in order to collect and analyse dates of human circadian rhythms using wearable biological sensors. At the same time, there are systems that use photosensors to record, analyze, and change light parameters, such as illumination and correlated color temperature, accordingly. Existing adaptive lighting systems provide regulation of light parameters according to the time of day and the values set by the control algorithm, without taking into account human physiological parameters. The additional consideration of physiological signals allows for individualized adjustment, lighting control according to individually selected scenarios, and reduces the harmful effects of additional light-emitting devices. Thus, the paper proposes an adaptive lighting system that takes into account the indoor and outdoor light indicators of a room and automatically adapts to human physiological data. The thesis, based on theoretical and experimental studies, provides an increase in the accuracy of measuring light characteristics by creating new and improving existing methods for measuring photometric characteristics. The thesis consists of an introduction, four chapters, conclusions, a list of references and 22 appendices. The scientific novelty is: 1. An approach is proposed to determine the integrated indicator of the relationship between human physiological parameters, light and electrical parameters of the adaptive lighting system, which can be used to control the light parameters of the environment in which person is staying. 2. An approach to modeling the work of the human heart in the form of a Van der Pol circuit, which is distinguished by taking into account the transmission effect between the heart and body tissues, which made it possible to simulate the work of the human heart to avoid noise and interference in the elements of an equivalent electrical circuit with further and accurate determination of the parameters of human circadian rhythms. 3. A mathematical model of the environment, which differs from the known ones by representing the dependencies of microclimate parameters and human physiological parameters in the form of fuzzy logical statements. 4. An electrical circuit diagram of sensors for measuring physiological parameters for determining human circadian rhythms and environmental parameters is proposed, which differs from the known ones by the possibility of determining and adjusting light and microclimate parameters to personal physiological parameters of a person. Practical significance of the work: 1. Technical solutions for an IoT system of adaptive lighting that integrates data on the individual human condition and environmental conditions for automatic lighting control are proposed. This allowed to improve the quality of life of people and increase the energy efficiency of lighting by 10%. 2. On the basis of the proposed mathematical models and methods, software environment was developed to measure biological signals and environmental parameters, in particular to support the functioning of the electrical circuit of sensors, which allows to adjust the fixed physiological needs of a particular person, adapt at a particular time to their changes, maintain comfortable conditions for people indoor staying. 3. Practical implementation of the developed IoT system of adaptive lighting in the projects "KUEHA" and "CeTi" at the TU Dresden.