EP2224308B1

EP2224308B1 - A system and a method for controlling the light intensity in a tunnel

Info

Publication number: EP2224308B1
Application number: EP09425078A
Authority: EP
Inventors: Andrea Paolo Bondi; Massimo Pescalli; Gian Pietro Picco; Renato Antonio Lo Cigno; Matteo Nardelli; Nicola Vernesoni
Original assignee: Siemens SpA
Current assignee: Siemens SpA
Priority date: 2009-02-26
Filing date: 2009-02-26
Publication date: 2012-10-24
Anticipated expiration: 2029-02-26
Also published as: EP2224308A1

Description

The present invention relates to a system and method for controlling the light intensity in a tunnel according to the appended claims.
The state of the art on road tunnels and underpass illumination systems is bound to open-loop control of the illumination level based on a single parameter (time of day or external illumination level or veil luminance). Ambient characteristics are taken into account only statically based in the project and dimensioning of the plant. Samples of these systems are: Reverberi SDL TC veil luminance sensor, Techno Team Video Photometer, Thorn North Star Lighting, US 2004160199 , GB2345998 and FR 2490363 .
International and national regulations for the illumination of road, tunnels, underpasses, and other similar infrastructures impose strict limits in terms of the luminance and contrast perception for drivers and users. Applicability goes beyond tunnels and roads and can be extended to any situation where the security, safety, or simply comfort of use, require well-defined luminance levels. Energy consumption may or may not be a primary concern, but the strict adherence to rules (in contrast to over-dimensioning) of the proposed system guarantees energy consumption minimization.
The present illumination system is composed of six main functional blocks as illustrated in Fig. 1. The core and innovation of the system are in Internal Measures, Controller, and in part in External Measures.
The External Measures block includes a set, possibly with a single component, of measurements performed outside the area of controlled illumination, which are related to the specific ambient and scope of the illumination. Such measures can include luminance measurement, traffic measures (for roads), weather and physical environment conditions, etc. Based on these measurements the Reference Definition block computes a reference set point (which is indeed a complex curve function of time and space) for the illumination.
The Lamps block is a set of illumination devices. It is possibly heterogeneous and can include natural illumination sources (such as light wells collecting and regulating the flow of sunlight) and artificial illumination sources such as incandescence lamps, LEDs, and in general any light-emitting device. The Actuators block includes means for regulating the light flow of the devices in the Lamps block. Actuation techniques may operate on single illumination devices or groups thereof. Regulation techniques include, but are not limited to: 1) switching on and off illumination devices; 2) changing the driving voltage or current; 3) changing the duty-cycle of current; 4) screening the light source.
The Internal Measures block is a complex ensemble of functions which include: 1) measuring one or more of the following quantities: luminance, illumination, temperature, infrared radiation, ultraviolet radiation, reflectivity of walls, floor and ceiling; 2) collecting and transmitting the above measures to one or more collection points called gateways; 3) elaborating and normalizing such information and measures; 4) communicating periodically or asynchronously the measures and information to the Controller.
The Controller block is a hardware device with computational capabilities that, based on a suitable algorithm, can regulate the actuators such that the actual illumination parameters as measured by the Internal Measures block do not differ from the said reference set point by more than a predefined quantity. The algorithms used by the Controller may include robust and optimal control theory techniques, heuristic adaptations and neural networks or other artificial intelligence techniques suitable to minimize the residual error between the reference set point and the actual measures.

SUMMARY OF THE INVENTION

1) The concept of gathering external measures of different kinds, as discussed above with respect to the External Measures block, is an improvement on the state of the art, which typically relies on a single kind of measurement. Present day systems for road tunnels use a camera-based sensor to identify the screen luminance; in other applications the illumination in some other key point is measured. Other systems simply use the time of day without any measurement. Our system can use single as well as multiple measures, enabling a computation of the reference set point based upon multiple parameters. Additional measures can be, but are not limited to:
1. a) presence of traffic;
2. b) traffic speed and/or density;
3. c) hazardous conditions like stalling traffic into a tunnel or ongoing security activities in other environments;
4. d) modified ambient conditions that alters the reaction of drivers (e.g., snow, rain, fog).
2) The dynamic setting of the reference set point, either done with a continuous algorithm or with a tabular function. In state-of-the-art systems the set point is not a reference, rather a working consequence of the actuators settings, which are computed off-line at design time.
3) The fine-grained control of illumination devices both in light level and in space, with the ability of compensating illumination in one point by properly regulating adjacent lamps.
4) The closed loop control of illumination based on a dense set of measures internal to the controlled system, which can control the entire and can drive it to the reference set point with a controllable error.

Claims

A system for controlling the light intensity in a road tunnel or in any other ambient with similar characteristics, hereinafter referred as area of controlled illumination, based on dense measurements of internal illumination-related quantities and other physical parameters, comprising:
- a set of illumination devices,

- actuator means for regulating the light flow of the illumination devices;

- internal measuring means for measuring internal illumination-related quantities ;

- controlling means for regulating the actuator means;

- external measuring means for performing external measurements of the ambient outside the area of controlled illumination;
characterised by
- reference definition means for dynamically computing a reference set point curve for the illumination of the controlled area, based on the external measurements and on a set of limits and/or criteria requiring well-defined illumination levels

- wherein said internal illumination-related quantities are collected with a Wireless Sensor Network and comprise one or more of the following quantities:
■ luminance, illumination, temperature, infrared radiation, ultraviolet radiation, reflectivity of walls, floor and ceiling;

- wherein said external measurements of the ambient outside the area of controlled illumination comprise one or more of the following measurements:
■ luminance, measurement, traffic measures, weather and physical environment conditions; presence of traffic; traffic speed and/or density; hazardous conditions like stalling traffic into the tunnel or ongoing security activities in other environments; modified ambient conditions that alter the reaction of drivers (e.g., snow, rain, fog) ;

- wherein the controlling means regulates the actuators means such that the measured internal illumination-related quantities do not differ from the reference set point curve by more than a defined quantity.
A system according to claim 1, wherein the Wireless Sensor Network is a system of sensing and communicating devices which are not connected by communication wires, but communicate through radio, infrared, or any other suitable means not based on wires, hereby including such devices which are powered by an external source, internal batteries, or ambient (solar, wind, vibrations, thermal, chemical, nuclear, etc.) energy collection systems, including, but not limiting to, such system that accumulate the collected energy in a battery or ultra-capacitor.
A system according to claim 1 wherein the controlling means is implemented though one or more PLCs.
A system according to claim 1 wherein the controlling means is implemented via a general computing device or system, including a distributed implementation on multiple computers.
A system according to claim 1, wherein the controlling means is implemented through a distributed algorithm running on embedded devices, including also a) the case where the controlling means is implemented directly in the wireless sensor network; and b) the case where the wireless sensor network is used also to drive the actuators of the lamps.
A system according to claim 5 wherein sensors and actuators are integrated in one device, including the case of co-location with illumination devices.
A system according to claim 1 wherein the measures are illumination measures taken on selected points of the area of controlled illumination and where the transformation to the reference set point is done via theoretical computation.
A system according to claim 1 wherein the measures are luminance measures.
A method for controlling the light intensity in a road tunnel or in any other ambient with similar characteristics, hereinafter referred as area of controlled illumination based on dense measurements of internal illumination-related quantities and other physical parameters, comprising the steps of:
- providing a set of illumination devices,

- providing actuator means for regulating the light flow of the illumination devices;

- providing internal measuring means for measuring internal illumination-related quantities ;

- providing controlling means for regulating the actuator means;

- providing external measuring means for performing external measurements of the ambient outside the area of controlled illumination;
characterised by
- providing reference definition means for dynamically computing a reference set point curve for the illumination of the controlled area, based on the external measurements and on a set of limits and/or criteria requiring well-defined illumination levels

- collecting said internal illumination-related quantities with a Wireless Sensor Network and wherein said internal illumination-related quantities comprise one or more of the following quantities:
■ luminance, illumination, temperature, infrared radiation, ultraviolet radiation, reflectivity of walls, floor and ceiling;

- measuring said external measurements of the ambient outside the area of controlled illumination which comprise one or more of the following measurements:
■ luminance measurement, traffic measures, weather and physical environment conditions; presence of traffic; traffic speed and/or density; hazardous conditions like stalling traffic into the tunnel or ongoing security activities in other environments; modified ambient conditions that alter the reaction of drivers (e.g., snow, rain, fog);

- by the controlling means, regulating the actuators means such that the measured internal illumination-related quantities do not differ from the reference set point curve by more than a defined quantity.