iLighting the World

ENSURE

System Architecture and Networking (SAN)

Eindhoven University of Technology

Introduction

ENSURE is the Philips, TU Eindhoven and TU Delft joint KWR project (KennisWerkersRegeling of Ministerie van Economische Zaken/ SenterNovem). Knowledge workers from industry will perform research jointly with and at the universities (TU/e and TUD). The knowledge workers will give essential feedback on the practical applicability of ideas, and at the same time the funds that this program introduces, create possibilities for universities to contribute essential ideas and knowledge in an open-innovation fashion as well as to exchange personnel. The main objective of the project is to develop intelligent lighting solutions for the world of tomorrow. On this front, there are several new research questions such as on; the interaction between the user and the system, the design of the algorithms for communication between sensors and light sources, and the easiness of the installation mechanism.

ENSURE consists of 4 workgroups (WG). The SAN contribution in ENSURE is divided into two of these workgroups, namely i) Intelligent Road Lighting (WG1) and ii) Buildings Without Switches (WG4). WG1 focuses on intelligent lighting systems inside and outside cities where an energy reduction of at least a factor of 2 in comparison to the currently available traditional non-intelligent systems is expected. WG4 concentrates on designing an intelligent and flexible lighting system which is adaptive in terms of behavior and modular with respect to configuration.

People Involved

SAN Contribution

In the former, we focus on intelligent and efficient road lighting systems and our aim is to provide software, scripts and interfaces to control lights for the Wizard of Oz study, in order to maximize user comfort while minimizing energy consumption. In the latter, our aim is to provide a software and network architecture to enable seamless integration of adaptive smart lighting into building spaces. Given the limitations of node alternatives (e.g. wireless light sensors, LED luminaries, actuators), the provided architecture needs to be light-weight. Therefore, the OSAS architecture is a good candidate for the baseline architecture of this system.

Intelligent Road Lighting

Traditional road lighting designs are based on on-off control systems, where all the luminaries are turned on when the ambient light falls under a certain threshold. However, using all the lamps in full-power mode causes a non-optimal scenario in terms of total energy consumption. In a road lighting system, one has to consider the user perceptions, such as the feeling of safety and the psychological mechanisms behind them. To further examine this problem, we establish a testbed where we can change the brightness level of each lamp using a software-controlled system. Here, we describe the experiment testbed, installed in one of the streets of TU/e campus, in detail along with the possible future work.

System Model

Our testbed consists of a computer, a segment controller (SC) and 10 outdoor luminaire controllers (OLCs) (one per each luminary). The computer is used for sending commands to and monitoring SC as well as for collecting and analyzing the feedback data received from SC. The system model is illustrated in the figure below.

SC is responsible for monitoring and controlling OLCs over the LonWorks network using the power-line communication. The brightness of each lamp is adjusted by OLCs, where a voltage value between 1-10V is set according to the requested brightness value via the power-line communication using LonTalk open protocol. In the project, CitySoul LED luminaries, a relatively new type of LED lamp launched in late 2009 by Philips, are used. Each luminaire includes 84 LEDs with a total power consumption of 106 W and light output of 8820 lm. A close-up photo of LED lamp is shown in the figure.

Using a simple setup shown below, we measure the voltage characteristics of the LED lamp. The measurements are done in a dark room in order to prevent the effect of any interfering light. The following figure presents the graph of the lux values versus the voltage supplied by OLC. As expected, the lamp behaves linearly with respect to the supplied voltage.

An OPC (Object Linking and Embedding (OLE) for Process Control) server is required for the communication between the SC and the computer in the control room. OPC is a widely accepted software application in the industrial field due to its properties, such as, plug and play, open standard and interoperability. Although one can access the SC using a web-based GUI via HTTP, we use LabView for building a GUI. LabView is a programming environment for creating user interfaces and heavily used in the industry for automation, measurement, test and control. It also includes an OPC client and allows a human operator to switch between different scenarios effectively. A snapshot of the GUI written in LabView is shown in figure below. The switch at the top starts the experiment according to the luminance values defined by the scenario number, which is entered at the box left of the switch. Another switch is placed at the bottom for turning off the interfering light poles around the testbed and the 'stop' button terminates the experiment instantaneously.

Experiment

The experiment is done on a street in TU/e campus where ten lamp posts are evenly placed. We installed LED lamps using a metal fork along with the traditional HID lamps as seen in figure.

The schematic of the experiment is given in figure below. Green circles and red squares represent the position of the LED lamps experimented and the position of interfering lamp posts, respectively. The blue star shows the location of the subjects who rated different scenarios according to the perceived safety. After initial experiments, we observed that the interfering lamp posts in the surrounding degrade the reliability of the questionnaire. In order to control interfering lamps, we installed additional OLCs to each of these posts and connected all of them to a second SC. Before doing an experiment, all of these interfering lamps are turned off via the GUI.

Future Work

Following the result of this study, a sensor box (including sensors, such as camera, microphone, passive infrared and radar) will be placed on each lamp post. Additional questionnaires will be administrated while participants are walking through the street and the results will enlighten us further on how to utilize the sensory information efficiently. Using the necessary inputs from these sensors, the system will adjust the luminance levels of each lamp. Our goal is a fully automatic and intelligent road lighting system where lamps react to the changes in the environment by adapting their brightness in real-time.

References

1. Y. A. W. de Kort, A. Haans, L. Geerdinck, D. van Gennip, M. Horst, and J. Servaes, "Psychological building blocks for dynamic road lighting: Understanding light's role in feelings of safety at night," in Proc. of LS12-WLED3 July 11-16, 2010, TU/e, the Netherlands, 2010.
2. C. Atici, T. Ozcelebi, and J. J. Lukkien, "Intelligent Architecture for Road Lighting," submitted to ICCE 2011.
3. LonWorks, "PLT-22 Power Line Transceiver User's Guide (110kHz-140kHz Operation)." [Online]. Available: http://www.viste.com/LON/tools/PowerLine/PLT22A.pdf
4. Philips, "LFC7065 Segment Controller," 2008. [Online]. Available: http://www.lighting.philips.com/dk_da/architect/luminaire/controls/pdf/k_lysstyring/starsence/starsence_LFC7065-segment_controler.pdf
5. Philips, \LLC7020 Outdoor Luminaire Controller," 2008. [Online]. Available: http://www.lighting.philips.com/dk_da/architect/luminaire/controls/pdf/k_lysstyring/starsence/starsence_LLC7020-outdore luminare controler.pdf
6. E. Co., "LonTalk Protocol Specification Version 3.0," 1994.
7. Philips, "CitySoul LED - BGP431," 2009. [Online]. Available: http://www.lighting.philips.com/nl_nl/service_center/downloads/citysoul_led_nl.pdf
8. X. Hong and W. Jianhua, "Using standard components in automation industry: A study on OPC Specification," Computer Standards & Interfaces, vol. 28, no. 4, pp. 386-395, 2006.
9. LabView, National Instruments. [Online]. Available: http://www.ni.com/labview/

Links

		System Architecture and Networking

		Eindhoven University of Technology

Last update: 12/02/2010