Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
  • H05B47/10—Controlling the light source
  • H05B47/105—Controlling the light source in response to determined parameters
  • H05B47/11—Controlling the light source in response to determined parameters by determining the brightness or colour temperature of ambient light
• • E—FIXED CONSTRUCTIONS
  • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
  • E06B—FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES
  • E06B9/00—Screening or protective devices for wall or similar openings, with or without operating or securing mechanisms; Closures of similar construction
  • E06B9/56—Operating, guiding or securing devices or arrangements for roll-type closures; Spring drums; Tape drums; Counterweighting arrangements therefor
  • E06B9/68—Operating devices or mechanisms, e.g. with electric drive
  • E06B2009/6809—Control
• • E—FIXED CONSTRUCTIONS
  • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
  • E06B—FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES
  • E06B9/00—Screening or protective devices for wall or similar openings, with or without operating or securing mechanisms; Closures of similar construction
  • E06B9/24—Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blinds
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B13/00—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion
  • G05B13/02—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric
  • G05B13/0265—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric the criterion being a learning criterion
  • G05B13/0275—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric the criterion being a learning criterion using fuzzy logic only
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
  • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

Definitions

• the invention relates to a control unit for a lighting control system according to the preamble of claim 1. Furthermore, the invention relates to a lighting control system, a lighting system, a method for controlling a lighting system, a computer program product and an HDR vision sensor according to claims, 3, 7, 8, 9 and 10, respectively. The invention furthermore relates to a control method according to the preamble of claim 11. The invention furthermore relates to a method for controlling a technical system, a computer program product and a control unit according to claims 18, 19 and 20, respectively.
• an office lighting system therefore not only comprises an electric lighting system but also devices for avoiding glare, for example window blinds.
• an office lighting system has to assure that there is always enough light on an office occupant's workspace, because otherwise the occupant cannot properly see his work, e.g. his paperwork or his computer keyboard.
• lighting control systems typically comprising a lighting control unit, different sensors and different actuators. Based on input values received from the sensors, e.g. illuminance sensors, the lighting control unit typically sends output values to the actuators which act on luminaires, window blinds and the like.
• Such lighting control systems are typically able to automatically guarantee a constant illuminance on an office occupant's workplane at every moment in time.
• a common way to avoid glare sensation for the occupant as well as guaranteeing enough light includes using a rudimentary ceiling-mounted luminance meter that measures the horizontal illuminance (typically on a workplane level) right below the luminance meter.
• the principle of a common controller which integrates this measured value is quite straightforward: a control loop starts and the system performs a data acquisition task to sample the current indoor lighting condition. In the next step, the horizontal illuminance is compared with a lower boundary limit, for example 200 lux. According to the output, the controller either executes new commands to modify the settings of a lighting system (e.g. sending commands to the lighting facility of the building, sun shadings and electric lighting system), or the control loop continues for further analysis.
• a lighting system e.g. sending commands to the lighting facility of the building, sun shadings and electric lighting system
• control unit for a lighting control system, wherein the control unit is configured to calculate output values based on input values, wherein the output values include control commands for a lighting installation, wherein the input values include information about a light distribution, preferably a luminance distribution, in a view field of an office occupant, and the control unit is configured to calculate said output values based on said input values in such a way that discomfort glare for the office occupant is avoided, while sufficient workplane illuminance is guaranteed and electricity consumption is minimized.
• control unit receives as input values information about a light distribution, preferably a luminance distribution, in the view filed of an office occupant enables the control unit to determine whether there is a risk of discomfort glare in the office occupant's view filed.
• the control unit can then efficiently and reliably avoid glare, for example by closing a window blind until the light distribution in the office occupant's view field is such that no discomfort glare occurs.
• the control unit can act on a complementary electric lighting system in order to guarantee an appropriate illuminance on the office occupant's workplane, for example between 300 lux and 500 lux, while avoiding to supply too much electric lighting in order to keep an electricity consumption as low as possible.
• the control unit is configured to carry out said avoiding of discomfort glare continuously.
• the term "continuously" means that the control unit is able to react immediately when discomfort glare occurs. This has the advantage of making the work environment very comfortable for the occupant because as soon as discomfort glare is detected, the control unit can intervene and for example move the window blinds such that the discomfort glare is overcome. However, it is also possible to have the control unit only periodically check whether discomfort glare occurs, for example every 5 minutes. In a particularly preferred embodiment, the control unit is configured such that it acts on the window blinds when a certain calculated glare value passes a certain threshold.
• the input values to the control unit comprise a sun profile angle, a current sun shading position and/or a current sun shading tilt angle and/or a current electric lighting power.
• a lighting control system comprises a control unit according to the invention and furthermore comprises a first light sensor, which is an HDR vision sensor, configured to at least partly supply said input values to the control unit. It is particularly preferred that the HDR vision sensor is configured such that it supplies said information about a light distribution in the view field of an office occupant to the control unit.
• the term "HDR vision sensor” is to be understood as follows: this photometric device allows for real-time capturing and analyzing of luminance maps of visual scenes with considerable accuracy and speed. It offers a 132dB intra-scene dynamic range encoded logarithmically with 149 steps per decade. Each HDR image therefore provides a complete record of the magnitude and spatial variation of the luminance in the field-of-view.
• HDR High dynamic range
• the first light sensor is configured to calculate a glare value based on light captured by the first light sensor, wherein the glare value preferably comprises a daylight glare probability, and the first light sensor is configured to send said glare value as input value to the control unit.
• the first light sensor is configured to calculate the glare value on-the-fly, meaning that the almost "real time" processed data, in particular the glare value, is provided to the control unit automatically, without any further offline or manual post-processing by means of any computer program.
• the first light sensor is configured to send said glare value to the control unit at least every 20 seconds, preferably at least every 15 seconds, more preferably at least every 13 seconds, most preferably every 5 seconds.
• DGP Daylight Glare Probability
• E v [lux] is the vertical eye illuminance
• L s i [cd/m 2 ] is the average luminance of glare source i
• ⁇ 5 ⁇ [sr] is the solid angle subtended by the glare source i and ⁇
• [-] is the Guth's position index for the glare source i, taking in to account the importance of the location of glare index with respect to the center of the image.
• Calculating the glare value directly in the HDR vision sensor has the advantage of making it possible to only send the glare value to the control unit when the glare value passes a certain threshold and/or is such that discomfort glare occurs. Like this, unnecessary data transfer between the HDR vision sensor and the control unit, which could slow down the lighting control system, can be avoided. However, it is also possible for the control unit to calculate the glare value and the HDR vision sensor to only send raw luminance data to the control unit. Using the daylight glare probability for assessing a risk of discomfort glare is advantageous because it is considered to be a very reliable assessment of risk of discomfort glare which can furthermore be comparably easily and quickly calculated.
• the first light sensor comprises a digital signal processor configured to carry out image processing and the calculation of said glare value and/or in that the first light sensor is configured to be mounted at a height between 100 cm and 140 cm above a floor of an office room, preferably at a height between 110 cm and 130 cm above said floor, most preferably at a height of approximately 120 cm above said floor.
• the first light sensor is configured to be mounted parallel to the line of view of the sitting office occupant, preferably next to the office occupant, or on a computer screen of the office occupant, or yet on a wall behind the occupant. Mounting the first light sensor in such a way has the advantage of obtaining realistic assessments of glare risk. However, it would in theory also be possible to locate the first light sensor differently, for example above the head of the office occupant.
• the lighting control system comprises a second light sensor, wherein the second light sensor is preferably an HDR vision sensor, wherein the second light sensor is configured to measure an illuminance of one or more workplanes of an office room in which the lighting control system is installed.
• the second light sensor is configured to be mounted on a ceiling of an office room and provides workplane illuminance values as input values to the control unit.
• Such a second light sensor has the advantage of making it extremely easy for the control unit to guarantee sufficient illuminances on the workplanes, because the control unit will always know about the actual illuminances on the workplanes and will be able to supply just as much additional electric light as needed, thus also minimizing the electricity consumption.
• a lighting system according to the invention which is preferably part of a building automation system, comprises a lighting control system according to the invention and further comprises a lighting installation, wherein the lighting installation comprises at least one lighting device and at least one window blind.
• the window blind is typically a Venetian blind or a roller blind.
• the lighting device is typically a ceiling-mounted luminaire, a freestanding luminaire or any other kind of luminaire or lamp.
• the control unit is configured to send the output values to the lighting installation such that, preferably at essentially every moment in time, discomfort glare is avoided, and preferably a best possible trade-off between discomfort glare minimization, workplane illuminance maximization and electrical power minimization is guaranteed.
• an algorithm is typically continuously running inside the control unit which continuously determines optimal set points for the window blinds' altitude and/or tilt, and the optimal lighting power.
• a method for controlling a lighting system in an office room comprises the steps:
• a glare value preferably comprises a daylight glare probability and/or a daylight glare index and/or a unified glare rating and/or a CIE glare index
• the calculating is preferably carried out by means of a digital signal processor of the HDR vision sensor
• a control unit preferably on the fly and/or continuously and/or event-based
• a data transfer from the HDR vision sensor to the control unit is carried out via a telemetry channel, wherein in this context the expression "telemetry channel” is to be understood as wired or wireless communication protocol to transfer data over pre-established channels to a remote agent such as a computer program or a repeater.
• a computer program product typically recorded on a computer-readable medium, comprises code for carrying out a method according to the invention.
• An HDR vision sensor comprises a fish eye lens, a CMOS light capturing sensor, and a digital signal processor, wherein the HDR vision sensor is configured to calculate a glare value, based on light captured by the light capturing sensor, wherein said calculation is preferably carried out on the fly, wherein the glare value preferably comprises a daylight glare probability and/or a daylight glare index and/or a unified glare rating and/or a CIE glare index, and the HDR vision sensor is configured to supply the glare value as input value to a control unit.
• the HDR vision sensor is spectrally calibrated and/or geometrically calibrated and/or photometrically calibrated, meaning that firstly, the spectral sensitivity of the sensor is modified through application of one or several glass- or gelatin-based optical filters so as to match the spectral sensitivity of the human eye ⁇ V( )). Secondly, the sensor is calibrated in order to eliminate the Vignetting phenomenon, a pure geometrical phenomenon, caused by the fisheye lens; reduction of an image's brightness or saturation at the periphery compared to the image center. Finally, the sensor is calibrated photometrically so that the value of each pixel is equal to the average luminance (e.g. in cd/m 2 ) of corresponding patch of the area in the field of view of the sensor.
• the average luminance e.g. in cd/m 2
• the HDR vision sensor works as follows: The light from its field of view arrives firstly on the fisheye lens.
• the fisheye lens collects the light and redirects the part of the light rays that are not parallel to its principal axes.
• all the light rays going through its principal axis pass through one or several optical filters.
• the optical filters in this case change the spectral composition of the light so as to pass only visible part of the light.
• the light rays arrive on the photodetector of the vision sensor where the light photons are transformed to voltage differences proportionally to the light intensity.
• the output of the photodetector is a matrix of 320 X 240 pixels in greyscale unit; ranging from 0 to 0123.
• the digital signal processing unit It is fed in the next step to the digital signal processing unit to perform the image analysis and extract the daylight glare value, such as the daylight glare probability. As soon as this variable is ready, it is sent over the telemetry channel to the remote agent as an input for the control unit.
• the problem is furthermore solved by a method for controlling a lighting system
• the method comprises a first sub-method
• the first sub-method comprises a first data acquisition step during which a set of current lighting parameters is acquired, a fuzzy logic step during which a fuzzy logic sequence is run in order to determine a preferred sun-shading position based on the set of current lighting parameters, a checking step during which a check sequence is run to decide whether a sun shading system forming part of the lighting system is to be actuated such as to reach the preferred sun-shading position, and an actuating step during which a command is sent to the sun shading system by which the sun shading system is forced into the preferred sun-shading position, if during the checking step it was decided that the sun shading system is to be actuated such as to reach the preferred sun-shading position, wherein the set of current lighting parameters comprises a visual comfort parameter.
• the visual comfort parameter is a delta discomfort glare probability (DDGP).
• DDGP delta discomfort glare probability
• a calibrated High Dynamic Range (HDR) vision sensor provides a discomfort glare index named Daylight Glare Probability (DGP), which, similar to any other variable that reports the occurrence probability of any phenomenon, ranges from 0% to 100%. This range is typically divided into four spans associated with subjective linguistic terms: imperceptible [0, 35%]; perceptible [35%, 40%]; disturbing [40%, 45%]; intolerable [45%, 100%].
• DGP_ref the threshold for imperceptible glare sensation is set to 35%. This threshold is typically referred to as DGP_ref.
• DDGP DGP_measured - DGP_ref.
• URR unified glare rating
• the set of current lighting parameters comprises a horizontal workplane illuminance and/or a solar height and/or an azimuth angle.
• the horizontal workplane illuminance is an illuminance value at a certain point of a predefined horizontal workplane, for example at 80 cm or 100 cm above floor level, the solar height is typically expressed in degrees, and so is the azimuth angle, which corresponds to an azimuth of the sun with regard to a building fagade.
• the preferred sun shading position comprises a first position value for a first sun shading and a second position value for a second sun shading.
• the use of two separate sun shading position values for two different sun shadings allows for a maximum amount of flexibility because the two sun shadings, which could typically be an upper sun shading and a lower sun shading, can then be actuated separately.
• the checking step comprises a time check and/or a threshold check and/or a seriousness check.
• the time check it is typically checked how much time has elapsed since a last sun shading position change, and only if a minimum amount of time has elapsed since this last position change, another sun shading position change is considered further.
• the minimum amount of time is typically at least 5 minutes, preferably at least 10 minutes, more preferably at least 15 minutes. Such a time check has the advantage to guarantee that amendments to the sun shading positioning are not occurring too often.
• the threshold check it is typically checked whether a modification of a sun shading position will lead to a sufficiently important change in window coverage percentage.
• a first threshold exists for increasing the window coverage percentage and a second threshold exists for decreasing it.
• the first threshold equals at least 5%, preferably at least 10%, more preferably at least 15% and/or the second threshold equals at least 10%, preferably at least 20%, more preferably at least 30%.
• the seriousness check it is checked whether the fuzzy logic rules have been sufficiently applied.
• the objective of the seriousness check is to find out whether the rule set of the fuzzy logic step is sufficiently utilized for deriving the sun shading position change.
• the seriousness of a whole rule base used in the fuzzy logic step is the sum of all fuzzy rules' weights. If the sum of the weights is close to 0, this means that the output value of the fuzzy logic step is not seriously determined.
• the output weights correspond to IRR parameters and/or outputs of an evalfis command in Matlab.
• the checking step comprises a visual comfort parameter check, wherein the visual comfort parameter check is preferably configured to override the time check and/or the threshold check and/or the seriousness check.
• the method comprises a second sub-method, wherein the second sub-method comprises a second acquiring step during which a second set of current lighting parameters is acquired, an illuminance assessment step during which an illuminance level is assessed, and an electric lighting commanding step during which a command is sent to an electric lighting system forming part of the lighting system in order to achieve a desired illuminance level, if during the illuminance assessment step it was found that the illuminance is insufficient.
• the electric lighting system is tuned either to "full power" mode or "dimming" mode.
• the full power mode is preferably activated in the case where the difference between the current measured illuminance level and the reference illuminance level (e.g. 300 lux) is larger than the illuminance level that can be maximally provided by the electric lighting system.
• the electric lighting system is tuned to "full power" mode ((300-100) lux > 150 lux). Otherwise, the lighting system is preferably set to dimming mode. By applying this strategy, the electric lighting energy demand is minimized.
• the electric lighting system is deactivated as the measured current illuminance level is larger than the reference illuminance value.
• Such a second sub-method meant to control an electric lighting system has the advantage that electric lighting can also be controlled.
• the separation into two distinct sub-methods allows for dealing with daylighting and electric lighting independently and flexibly. However, it would also be possible to control daylighting and electric lighting at the same time.
• the first sub-method is carried out before the second sub-method. This has the advantage to also try everything possible to use available daylight in the first place, and then to only add artificial lighting when it is really necessary. This order for the sub-methods can therefore be considered to help to cut down electricity demands. However, it would theoretically also be possible to carry out the second sub-method before the first one.
• this method comprises a calculation step during which a preferred system setting is determined based on at least one input variable, wherein the method further comprises a filtration step, during which it is assessed whether the technical system should actually really reach the preferred system setting, wherein the filtration step preferably comprises a seriousness check.
• This method cannot only be used in lighting but for example also for assuring that appropriate instructions are, for example, given to robots that interact with humans.
• the method for controlling a technical system comprises a fuzzy logic step as described above, in particular a fuzzy logic step during which a seriousness of a whole rule base used in the fuzzy logic step is the sum of all fuzzy rules' weights, and during the seriousness check it is checked whether this seriousness is above a certain threshold, and an action command to reach the preferred system setting is only issued if the seriousness is above the threshold.
• the method for controlling a technical system comprises a time check and/or a threshold check and or a first sub- method and/or a second sub-method as described above.
• the method for controlling a technical system comprises an override step configured to override the seriousness check and/or the time check and/or the threshold check.
• a computer program product according to the invention comprises code for carrying out any of the methods according to the invention.
• a control unit according to the invention is configured to carry out any of the methods according to the invention.
• Figure 1 A schematic view of an office room in which a lighting system
• FIG. 2 Flow diagram of a control method according to one embodiment of the invention
• FIG. 3 Fuzzy logic control step with four inputs and two outputs
• Figure 5 Schematic overview of rule aggregation during the fuzzy logic
• Figure 6 Zoom-in on output section of Figure 5.
• Figure 1 shows schematic view of an office room 1 in which a lighting system according to the invention is installed.
• office room 1 an office occupant 2 is sitting on a chair at a workplace in front of a computer screen.
• a surface on the table at the workspace of the office occupant 2 is referred to as workplane. This is typically an area of the table where the office occupant's 2 computer keyboard would be located.
• the office room 1 comprises a window 3.
• the window 3 is equipped with a window blind 4.
• the window blind 4 is made from fabric of beige color and is a roller blind.
• the office room furthermore comprises a daylighting system 5, which comprises a rounded surfaces coated with aluminum. This daylighting system 5 is configured to reflect daylight D that hits the aluminum coating onto a ceiling of the office room 1 , from where it is reflected downwards.
• the daylighting system 5 is equipped with a daylighting system blind 6, which is a roller blind.
• the office room 1 is furthermore equipped with two ceiling-mounted luminaires 7.1 , 7.2.
• These ceiling-mounted luminaires 7.1 , 7.2 are equipped with electric light sources such as LEDs or fluorescent tubes and are configured to supply artificial light to the office room 1 and in particular the office occupant's 2 workplane at times where not enough daylight D reaches the office room 1 through the window 3 and the daylighting system 5.
• the office room 1 is furthermore equipped with a control unit 8.
• the control unit 8 is linked to the window blind 4, the daylighting system blind 6 and to the luminaires 7.1 , 7.2.
• the control unit 8 is configured to create output values and to send them as instructions to the window blind 4, the daylighting system blind 6 and to the luminaires 7.1 , 7.2.
• These instructions can for example be dimming instructions for the luminaires 7.1 , 7.2 and/or up/down commands for the blinds 4, 6.
• the office room 1 comprises a first light sensor 9.
• the first light sensor 9 is an HDR vision sensor. It is mounted on a movable rod 10 at approximately 120 cm above floor level, i.e. approximately at an eye level of the office occupant 2.
• the first light sensor 9 is configured to measure a luminance distribution in a view field of the office occupant 2 and to calculate a daylight glare probability from this luminance distribution.
• the first light sensor 9 is furthermore configured to supply this daylight glare probability as input value to the control unit 8 via a telemetry network, which is typically a wireless network (not visualized in Figure 1 ).
• the office room 1 furthermore comprises a ceiling-mounted second light sensor 11 , which is also an HDR vision sensor.
• the second light sensor 11 is configured to measure an illuminance on the workplane of the office occupant 2.
• the control unit 8 and the light sensors 9, 11 form a lighting control system.
• This lighting control system, together with the blinds 4, 6 and the luminaires 7.1 , 7.2 form a lighting system of the office room 1.
• This lighting system operates as follows:
• the first light sensor 9 measures a visual discomfort index, for example the daylight glare probability, for the view field of the office occupant 2, and the second light sensor 11 measures the workplane illuminance for the office occupant 2 and detects the presence of the office occupant 2.
• the first light sensor 9 and the second light sensor 11 make their data available as input values to the control unit 8.
• the control unit then regulates the lighting installation of the office room 1 , namely the luminaires 7.1 , 7.2 and/or the window blind 4 and/or the daylighting system blind 6 based on these input values.
• first light sensor 9 is mounted on the rod 10 next to the office occupant 2 in Figure 1 , it is also possible to mount it on the computer screen of the office occupant 2 or yet on a wall or partition behind the office occupant 2. Furthermore, it is possible to foresee multiple first light sensors 9. This has the advantage to make it possible to more reliable detect discomfort glare in the office room 1.
• Image processing and calculation of the visual discomfort index is carried-out by the digital signal processor embedded in the first light sensor 9.
• the data transfer within the lighting system can be carried out by means of wireless or wired communication networks, or a combination of both.
• the first light sensor 9 communicates with the control unit 8 through a wireless communication channel, whereas the blinds 4, 6, the luminaires 7.1 , 7.2 and the second light sensor 11 are connected to the control unit 8 by wire.
• the first light sensor 9 continuously evaluates the daylight glare probability based on the luminance distribution detected by it and provides it as input value to the control unit 8.
• Other visual comfort indices such as Daylight Glare Index (DGI), Unified Glare Rating (UGR) and/or CIE Glare Index (CGI) are also measurable by the first light sensor 9.
• the control unit 8 comprises is a closed loop controller that is configured to apply different control strategies such as predictive algorithms and/or user- adaptive algorithms and/or fuzzy logic algorithms.
• the control unit 8 can furthermore be configured to not only control the lighting installation, but also to interact with control units for heating, ventilation and air conditioning, so-called HVAC control units, or to even act as a combined lighting and HVAC control unit.
• the ceiling-mounted luminaires 7.1 , 7.2 can be replaced by or combined with other ceiling-mounted luminaires and/or pendant luminaires and/or freestanding luminaires and/or recessed ceiling luminaires and/or recessed wall luminaires and/or spotlights and/or downlights.
• the blinds 4, 6 can have different embodiments such as internal or external roller blinds, or yet internal or external Venetian blinds.
• the second light sensor 11 can be installed directly above the workplane of the office occupant 2 (as shown in Figure 1 ), or at any other place on the ceiling of the office room 1.
• the workplane illuminances of several work stations and/or workplanes are measurable with one and the same second light sensor 11 , but it is also possible to foresee multiple second light sensors 11.
• Figure 2 shows a block diagram of a method for controlling a lighting system according to the invention.
• the method starts with a start step SO and ends with an end step S12. This procedure is called one cycle. As soon as one cycle is finished, the method is typically restarted.
• the method comprises two sub-methods.
• the first sub-method is responsible for defining and commanding the positions of a sun shading system forming part of the lighting system based on the captured data.
• the steps S1 to S7 belong to this first sub-method.
• the second sub-method is responsible for defining a state and commanding an electric lighting system forming part of the lighting system.
• the steps S8 to S11 belong to this second sub-method.
• a data acquisition step S1 and S8, respectively, is performed in order to provide the control method with the actual lighting conditions of the office room.
• the reason for dividing the control method into two sub-methods is to privilege the daylighting over the electric lighting by improving first the lighting condition of the office by adjusting the sun shading system.
• a calibrated High Dynamic Range (HDR) vision sensor provides a discomfort glare index named Daylight Glare Probability (DGP) (as explained in [1], see Section “Cited References” below) as input variable to be dealt with during the method.
• DGP Daylight Glare Probability
• the DGP similar to any other variable that reports the occurrence probability of any phenomenon, ranges from 0% to 100%. This range is divided into four spans associated with subjective linguistic terms: “imperceptible” (0% to 35%), “perceptible” (35% to 40%), “disturbing” (40% to 45%) and intolerable (45% to 100%).
• the threshold for imperceptible glare sensation is typically set to 35%.
• DGP_ref This threshold is referred to as DGP_ref.
• DGP_ref This threshold is referred to as DGP_ref.
• DDGP delta daylight glare probability
• DDGP DGP_measured - DGP_ref, wherein the variable DGP_measured is a measured DGP at a particular moment in time and wherein DGP_ref is a customized DGP for a particular office occupant, in particular an office occupant who will be using the lighting system which is controlled by the control method according to the invention.
• the DDGP is used as an input to the first sub-method according to the following procedure:
• a data acquisition step S1 the current indoor lighting condition in an office room is sampled.
• four current lighting parameters are determined during this step, namely the DDGP 12, a horizontal workplane illuminance 13, a solar height 14 and an azimuth angle 15. These four current lighting parameters are used as inputs for the fuzzy logic step S2, as can be seen in Figure 3.
• the outputs 16 and 17 of the fuzzy logic step S2 of the present embodiment are new sun shading positions 16 and 17 for two sun shadings, which correspond to the preferred sun-shading position at a given moment in time.
• a fuzzy logic sequence is run in order to determine the preferred sun-shading position based on the set of current lighting parameters.
• new commands for the positions of the sun shading system and the seriousness of the fuzzy logic step about these commands are created as outputs of the fuzzy logic step S2. More details regarding the fuzzy logic step S2 will be explained later on.
• the outputs of the fuzzy logic step S2 are used as input variables for a checking step.
• This checking step comprises a time check S3, a threshold check S4 and a seriousness check S6.
• the reasons for the presence of the checking step is that the inventors have found out that the commands created by the fuzzy logic step S2 cannot always be applied as such to the sun shading system for the following two reasons:
• the number of the sun shading and electric lighting status amendments should be minimized so as to avoid bothering the building occupants; 2) The system should remain as agile as possible when there is a high risk of glare sensation.
• a minimum time interval e.g. 15 minutes, is introduced in order to avoid frequent amendments of the shading position. If there is any command to the sun shading system generated by fuzzy logic step S2 before this minimum time interval (which typically starts once a sun shading positioning has been effectuated) has elapsed, the command is ignored and the method continues directly with a data logging step S11 (see below). However, in case this minimum time interval has elapsed, the command is passed to the threshold check S4.
• a threshold is introduced in order to avoid jerky, and occasionally useless and annoying movements of sun shading system.
• a lower threshold namely 15%
• a higher threshold is chosen for a command that would lead to a decreasing of the window coverage percentage (in other words: an opening of sun shading), for which a threshold of 30% is chosen.
• the reason for these different thresholds is the fact that it is preferable to encourage more agile glare protection capacity and therefore to accept lower thresholds for cases where sun shadings are to be closed.
• the threshold of 15% means that only such commands are carried out which lead to at least 15% more window area being covered by the sun shading than before.
• the seriousness check S6 the seriousness of the command generated by the fuzzy logic step S2 is taken into account.
• the inventors have found out by means of experiments that not all of the commands are serious and strong enough to be taken into consideration.
• the reason for this is that the structure and outcome of the fuzzy logic step S2 depends basically on the experience of the controller designer who designs the fuzzy logic step S2 and in particular the rules.
• the controller designer defines each rule based on some subjective observations and assumptions regarding the behavior of the system states in different situations. Most of the time, these rules might not be sufficient enough to cover all the possible conditions that a system might experience. Hence, the outcomes might not be "serious" and "strong” all the time.
• a threshold for seriousness of the output of the fuzzy logic step S2 is defined. This threshold is chosen to be 15% of seriousness. If any command has a seriousness of more than 15%, it is sent to the sun shading system to execute it. If not, the command is ignored and the method continues directly with the data logging step S11 (see below).
• the first sub-method furthermore comprises a visual comfort parameter check S5.
• This visual comfort parameter check S5 is assigned to keep the system agile enough to react to sudden strong risks of glare sensation. If the DDGP is higher than a certain threshold - for example 5% -, regardless of any possible outcomes of the checks S3, S4 and S6, the command of the fuzzy logic step S2 is passed on to the actuators.
• actuating step S7 the commands having been filtered during the checking step are executed.
• This actuating step S7 sends the commands to the motors of the sun shading system. This is the end of the first sub-method of the control cycle.
• the second sub-method of the method for controlling a lighting system begins with a second data acquisition step S8 during which the new indoor lighting conditions - i.e. the lighting conditions which have been reached after the first sub-method has been carried out - are re-evaluated.
• an illuminance check step S9 it is determined if a horizontal illuminance on a predefined workplane is high enough. If this is the case, there is no need for applying electric lighting. In this case, the method continues directly with the data logging step S11 (see below). Otherwise, the necessary complementary illumination intensity needed by the electric lighting is determined. This can include determining a dimming level of the electric lighting system if a dimmable system is in place.
• a lighting step S10 lighting commands in line with the outcome of the illuminance check step S9 are applied to the electric lighting system.
• fuzzy inference is the process of formulating the mapping from a given input to an output using fuzzy logic. It is composed of five steps: i) fuzzify inputs, ii) apply fuzzy operators, iii) apply implication method, iv) aggregate all outputs and finally v) deffuzify.
• all the outputs of the rules are aggregated. Because decisions are based on the testing of all of the rules in a Fuzzy Inference System (FIS), the rules must be combined in some manner in order to make a decision. Aggregation is the process by which the fuzzy sets that represent the outputs of each rule are combined into a single fuzzy set.
• FIS Fuzzy Inference System
• the input of the aggregation process is the list of "truncated output" functions returned by the implication process for each rule.
• the output of the aggregation process is one fuzzy set for each output variable.
• the output of each rule of a fuzzy process is combined, or aggregated, into a single fuzzy set whose membership function assigns a weighting for every output (tip) value.
• the explained principles are valid for the crisp output sets; these sets are used in this embodiment for generating commands for the position of the two sun shadings.
• the centroid method is applied to return the center of an area under a curve that represents the result of aggregation.
• the mathematical operation behind the centroid method is depicted in Equation 1 , where the value y 0 is the value of the fuzzy inference output, ⁇ ' (yj) is the value of the aggregated result at yj and j is the sweeping parameter over the output range and F is the upper maximum of the output range.
• the "seriousness" value of the present embodiment is the denominator of Equation 1 , which is the weight of fuzzy or crisp output sets.
• Equation 2 In the case where the sum of the aggregated results is too small, it implies that none of the rules are seriously contributed to the aggregated results. In this case, although y 0 , the final output, is mathematically calculable and it is theoretically valid, it is not derived based on considerable aggregated values. This case normally happens when the rules does not have much to "say" based on the inputs.
• the input variables are fuzzified: according to predefined membership functions, the numerical variables are translated to fuzzified variables.
• the membership functions of the DDGP are defined as shown in Figure 4. They are defined based on the boundaries defined for the DGP in document [1] by Wienold and Christoffersen (see details in Section "Cited References” below). Reference to the definitions of the boundaries for the DGP in document [1] is hereby made.
• Figure 5 shows a rule-base according to the invention predefined by a control method designer. Based on this rule base, the control method provides the proper positioning outputs for two sun shading devices as follows:
• the inputs are inserted to each rule and based on the internal mechanism of the rule, and then the decisions for the position of sun shadings are determined.
• the decision of the rule for each shading position is created by a) the position of the sun shading device, for example 30% window coverage; and b) the "seriousness" of the rule about this decision.
• the respective position of the sun shading device is shown by the horizontal positions of the striped vertical bars 19 in the white output boxes and the seriousness is shown by the ratio of the length of the thick black bars 18 with respect to the total height of the striped vertical bars 19.
• the striped vertical bar 8 is located in the far right side of the white box (e.g.
• the weighted sum of the output of each rule determines the final value and the seriousness of the fuzzy logic controller for this set of inputs.
• the final outputs are shown in the bottom right corner of Figure 5 and at the bottom of Figure 6, respectively.
• the sun shading window coverage for sun shading #1 is about 100% as depicted in Output 1 (horizontal position of the checkerboard pattern vertical line v1 ) and for sun shading #2 it is about 60% as depicted in Output 2 (horizontal position of the checkerboard pattern vertical line v2).
• a method for controlling a lighting system in an office room comprises the steps:
• a glare value preferably comprises a daylight glare probability and/or a daylight glare index and/or a unified glare rating and/or a CIE glare index
• the calculating is preferably carried out by means of a digital signal processor of the HDR vision sensor
• a control unit preferably on the fly and/or continuously and/or event-based
• the method further comprises a first sub-method, wherein the first sub- method comprises:
• a checking step (S3, S4, S5, S6) during which a check sequence is run to decide whether a sun shading system forming part of the lighting system is to be actuated such as to reach the preferred sun-shading position
• an actuating step (S7) during which a command is sent to the sun shading system by which the sun shading system is forced into the preferred sun- shading position, if during the checking step it was decided that the sun shading system is to be actuated such as to reach the preferred sun-shading position, wherein the set of current lighting parameters (12, 13, 14, 15) comprises a visual comfort parameter (12).
• each claim may stand on its own as a separate embodiment. While each claim may stand on its own as a separate embodiment, it is to be noted that - although a dependent claim may refer in the claims to a specific combination with one or more other claims - other embodiments may also include a combination of the dependent claim with the subject matter of each other dependent or independent claim. Such combinations are proposed herein unless it is stated that a specific combination is not intended. Furthermore, it is intended to include also features of a claim to any other independent claim even if this claim is not directly made dependent to the independent claim.

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• 2017
  • 2017-06-12 WO PCT/IB2017/000710 patent/WO2017216623A2/en unknown
  • 2017-06-12 EP EP17745487.3A patent/EP3469860A2/de active Pending

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