Hisanori Ikegami

Estimation of illuminance sensor positions and improvement of energy efficiency in the distributed control lighting system

We propose a distributed control lighting system (hereafter, Intelligent Lighting System) for achieving personal illuminance. The Intelligent Lighting System changes the luminances for individual lights based on a self-distribution algorithm. It learns the influence of lights on illuminance sensors through regression analysis and controls the lighting to achieve the required illuminance in the required places. When the numbers of lights and illuminance sensors increase, however, an error in the regression coefficient becomes larger; accordingly, the influence of the lights on illuminance sensors may not be correctly estimated. To solve this problem, this study proposes a method for correcting the results of the learning of the influence of the lights on illuminance sensors by estimating the illuminance sensor positions. With the proposed method, we estimate the illuminance sensor positions and determine the distances between the individual lights and illuminance sensors to correct the results of the learning according to the distances. The method proposed in this study enables the illuminance sensor positions to be estimated with an error of less than 1 m. Moreover, the method makes it possible to appropriately control lighting luminance compared with conventional method, achieving an improvement in illuminance convergence speed as well as a 5% reduction in power consumption.

An Intelligent Lighting System with a Seat Management Mechanism

We have been researching and development of an Intelligent Lighting System to provide desired illminance to a desire place. We have implemented the Intelligent Lighting System in actual office spaces for verifying its utility. The Intelligent Lighting System judge that illuminance is unnecessary in the place, when the worker has left his seat. In the Intelligent lighting Systems we have implemented in actual offices, every worker ask to change their seating status through a user interface on the web. However, the seating information was not properly managed, the workers who are away from the office are often regarded as seated, resulting in excessive and unnecessary consumption of electricity for lighting. Therefore we use a seating sensor that can judge to automatically detect workers seating statuses of a person by sensing the pressure. In this research, an Intelligent Lighting System with a seat management mechanism to automatically detect workers seating statuses was built using a seating sensor. Verification testing was implemented in actual offices, to determine how much savings can be achieved in the consumption of electricity for lighting.

Combination of Preferred Illuminance and Preferred Color Temperature for Work

We have been conducting research on an Intelligent Lighting System which is able to provides required illuminance for each worker. In the Intelligent Lighting System, it is possible to provide illuminance and color temperature in an arbitrary location by incorporating chroma sensor into the system. By simply setting a target illuminance and target color temperature, the worker can create the optimal illuminance and color temperature environment for work. However, when setting the target illuminance and target color temperature, selecting the illuminance as well as a color temperature suitable for that illuminance may be difficult for users because it may be unclear which color temperature should be set for the selected illuminance. Thus, in this research we conduct experiments related to illuminance and color temperature, and investigate the combination of preferred illuminance and preferred color temperature for work. By applying the experiment results to the Intelligent Lighting System and simplifying the operations of setting the target illuminance and target color temperature, we aim to improve the level of comfort for worker in the office equipped with LED lighting.