Sensor-driven lighting control with illumination and dimming constraints

We consider daylight and occupancy adaptation in a lighting system with sensor-integrated luminaires. Each luminaire has an occupancy sensor and a light sensor and communicates with a central controller. The sensors communicate local presence state and illuminance measurements to the controller, where dimming levels for the luminaires are computed. We consider an optimization framework wherein the objective is to minimize the power consumption subject to illumination and dimming constraints. The illumination constraint is to achieve an illumination value at the light sensor that is above a specified set-point, depending on the presence state. The dimming constraints are to achieve spatial uniformity in dimming levels of the luminaires, with the dimming levels being within physical limits. We consider two spatial uniformity functions depending on prior information available from commissioning of the luminaires. We propose an iterative method for optimization to determine the dimming levels. The proposed method and optimization framework is compared with existing approaches, in terms of spatial dimming uniformity and achieved illumination, in an open-plan office lighting model.