Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/01—Detecting movement of traffic to be counted or controlled
  • G08G1/04—Detecting movement of traffic to be counted or controlled using optical or ultrasonic detectors
• • 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
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy

Definitions

• the present invention relates to a method and a system for detecting a living being or an object on a traffic lane.
• the detection system may in particular be used in different applications, such as:
• the patent US6417783B1 describes a solution which comprises a sensor mounted at the top of a mast placed at the roadside.
• the solution notably uses photovoltaic cells to be autonomous in electrical energy and includes a wireless communication module to transmit the measurement data to a remote central unit.
• a wireless communication module to transmit the measurement data to a remote central unit.
• Patent application GB2478560A describes an "intelligent" signaling pad 0 integrated into the roadway.
• This pad has the distinction of being active. Its operation consists in particular in employing a light detector to detect the intensity of light created by the lights of a vehicle, in processing the signal obtained thanks to a microprocessor and in activating or not signaling diodes according to the processed signal.
• the stud is powered by a photovoltaic cell. This solution is not DD18780 AB
• the object of the invention is to propose a method and a system for detecting the presence of a living being or of an object on a traffic lane, which is particularly simple to install, which does not impact the environment. in particular at the aesthetic level, which remains particularly robust to withstand the different climatic conditions or those which are linked to its implantation environment and which can adapt to different external operating conditions, in order to obtain optimal results.
• This object is achieved by a method for detecting the presence of an object or of a living being on a traffic lane, implemented by a detection system which comprises:
• Photovoltaic equipment comprising at least one photovoltaic sensor intended to be integrated into said traffic path
• a detection step implemented to detect the presence of an object or of a living being when said characteristic variation parameters are identified and / or of determining characteristics of said object or of the living being detected from said parameters. variation in characteristics identified. DD18780 AB
• the method comprises a step of preprocessing the measurement signal obtained.
• the method comprises a step of determining the length of an object from the variation parameters characteristic of the measurement signal obtained for said measured electrical quantity.
• the method comprises:
• the electrical quantity is chosen from the short-circuit current of the photovoltaic equipment, the open circuit voltage of the photovoltaic equipment, the maximum power current of the photovoltaic equipment, the maximum power voltage of photovoltaic equipment or a combination of several of these parameters.
• the level of brightness is determined from several thresholds delimiting at least three zones:
• the method consists in measuring two electrical quantities.
• the invention also relates to a system for detecting the presence of a living being or of an object on a traffic lane, said system including:
• Photovoltaic equipment comprising at least one photovoltaic sensor intended to be integrated into said traffic path
• Means for processing the measurement signal obtained for said at least one measured electrical quantity comprising a module for determining variation parameters characteristic of said measured electrical magnitude and a first detection module configured to detect the presence of a vehicle or a living being when said characteristic variation parameters are identified.
• the processing means are configured to apply a preprocessing to said measurement signal obtained.
• the processing means are configured to apply to the measurement signal obtained an extraction solution chosen from one or more of the following solutions:
• the processing means comprise a module for determining the length of an object from the variation parameters
• the photovoltaic equipment comprises a first photovoltaic sensor and a second photovoltaic sensor, said second photovoltaic sensor being spaced by a non-zero fixed distance relative to the first photovoltaic sensor according to a direction of circulation of the object or said living being on said floor,
• the processing means comprise a module for determining the speed of said object from said fixed distance between said first photovoltaic sensor and said second photovoltaic sensor, from a first detection instant5 determined on a first measurement signal obtained for said electrical quantity measured at the first photovoltaic sensor and at a second detection instant, distinct from the first detection instant, determined on a second measurement signal obtained by said electrical quantity measured at the second photovoltaic sensor.
• the electrical quantity is chosen from the short-circuit current of the photovoltaic equipment, the open circuit voltage of the photovoltaic equipment, the maximum power current of the photovoltaic equipment, the maximum power voltage of photovoltaic equipment or a combination of several of these parameters.
• the system comprises a brightness sensor configured to supply brightness data to the processing means and in that the processing means are configured to determine the electrical quantity measured as a function of said brightness data supplied by the sensor of brightness.
• the photovoltaic equipment comprises one or more photovoltaic cells.
• the photovoltaic equipment is produced in the form of one or more photovoltaic panels glued to the road.
• each photovoltaic panel is in the form of a one-piece element comprising a first layer forming said sensor.
• the system comprises a communication module configured to exchange data with a remote central unit 5 by wired or wireless link.
• FIG. 1A schematically illustrates the detection system of the invention used to detect an object or a living being on a traffic lane;
• FIG. 1B represents a particular embodiment of the system of the invention
• FIG. 2 schematically illustrates, according to a particular embodiment, an example of the structure of the detection system of the invention
• FIG. 3 schematically represents a photovoltaic type sensor which can be used in the detection system of the invention
• FIGS. 4A to 4C represent several alternative embodiments of a photovoltaic sensor of the detection system of the invention.
• FIG. 5 represents a curve l-V characteristic of a photovoltaic element (cell or module), showing the parameters of interest for the system of the invention
• FIG. 6 represents curves l-V characteristic of a photovoltaic element (cell or module) obtained according to different levels of irradiance
• FIG. 7 represents a curve of variation of the power generated by a photovoltaic sensor as a function of time, which makes it possible to illustrate the characteristic parameters of variation during the presence of shading on the sensor;
• FIGS. 8A and 8B represent two curves of variation of the voltage in open circuit measured by a system sensor, during the passage of a vehicle5 provided with lighting, on the traffic lane, respectively at night and in low light; DD18780 AB
• FIG. 9 represents a particular embodiment of the detection system of the invention, in which two photovoltaic sensors of the system are separated by a fixed distance;
• FIG. 10 represents two variation curves of the power generated by
• Figures 1 1 A and 1 1 B each show two curves of variation of the open circuit voltage generated by two photovoltaic sensors of the system0 as a function of time, the two sensors being separated by a fixed distance, Figure 1 1 A being obtained by night measurement and Figure 1 1 B by measurement at dusk; This figure illustrates the principle of determining the speed of the vehicle under these particular conditions;
• FIG. 12 illustrates the principle of determining the length of a vehicle by the detection system of the invention
• FIG. 13 represents the power variation curve obtained by the system of FIG. 12, and illustrating the principle of determining the length of a vehicle
• FIGS. 14A and 14B represent a curve of variation of the current as a function of time making it possible to illustrate the passage respectively of a heavy vehicle and a cyclist over a sensor of the detection system of the invention
• the invention relates to a system 2 for detecting a living being or an object on a traffic lane. This principle is shown diagrammatically in FIG. 1 A.
• road we mean for example a road or equivalent, a path, a cycle track, a parking lot (underground or not), a sidewalk ...
• the detection system 2 notably comprises a photovoltaic type equipment 0 integrated into the traffic lane (for example the road in FIG. 1A).
• photovoltaic equipment subjected to light energy, makes it possible to produce electrical energy.
• the photovoltaic equipment comprises one or more photovoltaic sensors C_pv_i (i can range from 1 to n depending on the configuration5 of the system).
• Figure 1A shows a single photovoltaic sensor system C_pv_1.
• each photo voltaic sensor C_pv_i in the system can DD18780 AB
• Photovoltaic cells can be organized in series / parallel in each collector or photovoltaic element used. They can be encapsulated to be protected from external elements (humidity, shocks ).
• the sensor C_pv_i is represented with a chain of Photovoltaic cells Cell_k connected in series.
• Bypass diodes can be used in each photovoltaic sensor in the system.
• a bypass diode is for example placed in parallel with a group of cells in series and makes it possible to derive the current of the group of cells when one of the cells of group 0 is shaded. Without such a diode, the shadow cells heat up and are susceptible to destruction.
• the detection system 2 comprises means of measurement M_V, MJ of at least one electrical quantity at one or more of the photovoltaic cells of the sensor.
• the sensors of the photovoltaic equipment5 can be identical or different, in particular in the electrical quantity measured / monitored.
• Each C_pvJ photovoltaic sensor can be produced in the form of one or more photovoltaic panels of the type described in patent applications W02016 / 016165A1 and W02016 / 016170A1.
• the slabs can be placed contiguously and contiguously on the traffic lane.
• FIG. 4A represents an architecture with three contiguous photovoltaic panels, each panel itself integrating several photovoltaic cells.
• the three tiles can be combined in the same system sensor, or each form a separate sensor from the system or even from several systems.
• Each panel can include one or more photovoltaic sensors of the detection system.
• each sensor of the photovoltaic equipment can comprise either a photovoltaic cell for measuring the short-circuit current Icc (FIG. 4B) because a large surface area maximizes the value of Icc , i.e. a set of cleaved cells (cut into small pieces - Figure 4C) put in series to measure the open circuit voltage Voc with greater precision (Nb of cells x 0.6V in series, because each cell provides 0 , 6V), either a combination of the two means, or yet another structure.
• Icc short-circuit current
• the detection system 2 can comprise a BATT battery charged by said photovoltaic equipment and which makes it possible to make the detection system completely autonomous in electrical energy, day and night.
• the system can then include an electrical energy management module.
• a C_pv_i photovoltaic sensor as used in the system can be used in at least two separate configurations. In a first configuration, it can fulfill both a sensor role and an electrical energy generation role. To generate electrical energy, it is then connected to a CONV converter of the system, controlled to charge a battery or to send electrical energy back to the electrical network.
• each photovoltaic sensor is therefore designed and installed to operate in the following two operating modes:
• the photovoltaic sensor 5 is therefore connected to the CONV converter connected to the electrical network and / or to a battery (for example that of the system) to supply electrical energy;
• a non-production operating mode The sensor is therefore used only in sensor mode to carry out the measurements necessary for detection;
• the system can then include switching means for connecting / disconnecting each photovoltaic sensor of the converter and thus changing from the production operating mode to the non-production operating mode and vice versa.
• the sensor C_pv_i can only fulfill its role as a sensor.
• the photovoltaic sensor is therefore designed and installed to operate only in a non-production operating mode as defined above. It is then used mainly as a sensor (only a power supply function of the detection system can still be assigned to it in order to make the system autonomous - but we will still consider that its main function is that of sensor).
• the system 2 can also include one or more COM communication modules controlled to receive measurement data from the measurement means and send data to a remote central processing unit 1.
• Communication modules can be wired or wireless. They are controlled by the processing means to send / receive the data.
• the photovoltaic equipment used in the detection system may be part of a more global photovoltaic installation, intended for electrical production only.
• This photovoltaic installation of electrical production can be formed of
• a first principle of the invention consists in determining the electrical quantity or quantities to be measured, according to the ambient light level. In other words, it is a question of taking account of the fact that it is day, night or that it is an intermediate situation, between day and night.
• the electrical quantity measured at one or more cells of the photovoltaic equipment of each sensor and necessary for its operation as a sensor is advantageously an electric current and / or5 an electric voltage.
• the electrical quantity or the electrical quantities can thus be chosen from:
• Each sensor of the photovoltaic equipment of the system can therefore integrate means for measuring one or more of these electrical quantities (see above 5 means of measurement M_V, M l).
• photovoltaic equipment (cell or module with several cells) is characterized by a characteristic curve IV as shown in FIG. 5 and which is directly linked to the characteristic of the photovoltaic cell that it uses.
• the voltage which is present when no current flows 0 is called open circuit voltage Voc.
• the current present when there is no voltage is called short-circuit current Icc.
• the point of maximum power of the photovoltaic equipment corresponds to the point of nominal efficiency of the equipment.5 It is defined by a voltage called voltage at maximum power V mpp and by a current called current at maximum power l mpp .
• Figure 6 shows the curves DD18780 AB
• a second principle of the invention consists in determining the phenomenon to be detected, as a function of the level of brightness determined, in order to deduce therefrom the processing mode to be carried out. It will then be a question of knowing whether we are in the case of detection of a shade (in general when it is day) or in the case of an increase in light (in general when it is night, by the light generated by vehicle lights). Depending on the phenomenon to be detected, the processing mode of the measured signal will be different.
• the system may include a CJum light sensor configured to measure the ambient light of the system and determine, as a function of the light level, the relevant electrical quantity or quantities as well as the phenomenon to be detected.
• a CJum light sensor configured to measure the ambient light of the system and determine, as a function of the light level, the relevant electrical quantity or quantities as well as the phenomenon to be detected.
• the ambient light level and therefore the day / night distinction, is determined directly by the photovoltaic sensor itself.
• the detection system includes processing means.
• the processing means may include at least one central processing unit UC and storage means, for example integrated into the central processing unit. They can be in the form of a programmable controller comprising input modules and output modules. On these input modules, the processing means can receive:
• the detection system 2 can include several sensors (C_pv_1, 5 C_pv_2 as in Figure 2 described below), it can include a central unit DD18780 AB
• the processing means are configured to execute different modules
• One or more control modules intended to place the detection system 2 in the configuration desired and necessary for the detection (control of each sensor in production mode or non-production mode, ...);
• the processing means can disconnect the production mode and switch to non-production mode.
• the electrical quantity or quantities to be measured may differ.
• the system In production mode, the system can rely on measurements of the current at maximum power and / or the voltage at maximum power.
• non-production mode the system can rely on measurements of the short-circuit current and / or the open circuit voltage.
• the brightness level can be characterized from several thresholds.
• the processing means can be configured to manage several thresholds defining the following operating zones:
• a first zone defined under a low brightness threshold The processing means are in a "night" processing mode;
• the processing means are in a "day" processing mode
• a third intermediate zone situated between the two brightness thresholds The processing means are in an intermediate day / night processing mode.
• FIG. 1B represents a detection system as described above, all the components of which are integrated in one and the same monobloc element, forming a slab to be bonded to the traffic lane.
• a first upper layer forms the photovoltaic sensor.
• One or more lower layers5, produced in one or more housings, contain the electronic circuits of the system, the central unit UC, the means for measuring current MJ and voltage M_V, the converter CONV, the battery BATT, and the module for COM switching.
• Several slabs of this type can be glued to the traffic lane, for example contiguously or spaced depending on the application envisaged (speed measurement, de0 length, simple detection, etc.).
• Each panel of this type can communicate with the remote central unit 1 thanks to its COM communication module, by wired or wireless link (for example via a ZIGBEE type network).
• FIG. 2 schematically represents an exemplary embodiment of the detection system.
• the system can have the following characteristics: DD18780 AB
• At least one first sensor C_pv_1 is configurable in production mode or in non-production mode
• Processing means can control the operating mode of the first sensor, to place it in production mode or in
• At least one second sensor C_pv_2 is in non-production mode only, dedicated to measurements;
• the processing means UC can control the current measurement means and the voltage measurement means at the level of each sensor.
• C_pv_1 or C_pv_2 in an individualized manner (this principle is schematized by the control points S_V_1, S_l_1, S_V_2, S_l_2 which make it possible to connect / disconnect the measurement means of the central unit);
• the processing means UC can determine which electrical quantity (s) is (are) useful for the system, taking account for example of the level of brightness, of the processing mode to be carried out (shading detection or increase in light) and of the operating mode in production or out of production of each sensor, and thus receive the measurement data of each selected electrical quantity (this principle is shown diagrammatically by the 0 control points S_V_1 .1, S_V_1 .2, S_l_1. 1, S_l_1 .2 for the first sensor and by the control points S_V_2.1, S_V_2.2, Sl_2.1, S_l_2.2 for the second sensor, these control points being controlled by the central processing unit UC to select each electrical quantity to be treated); In FIG. 4, all the control points controlled by the central unit are generally defined5 S X.
• the detection system of the invention can be integrated into a more general electrical production installation comprising photovoltaic modules (for example in the form of panels) dedicated to the production of electricity.
• Figure 2 thus shows a photovoltaic module M_pv connected to a converter to supply electrical energy to charge a battery.
• the detection system can DD18780 AB
• the electrical production is only intended for the electrical supply of the detection system, a low power is then taken to supply the detection system.
• the measurements carried out can then be based on variations in the open circuit voltage Voc of the equipment. Excess energy not needed to power the system will be stored in a battery or a super-capacity to allow the system to operate autonomously, especially at night.
• the detection system 2 can rely on both the variations of the short-circuit current Icc and the open circuit voltage Voc.
• a sensor dedicated to the measurement for example infrared or other
• infrared or other can be integrated into the system and activated.
• Processing can easily be carried out and configured to extract the characteristic parameters necessary for one or more of the aims pursued (see below, detection, determination of speed, length, etc.). It can be integrated into the CPU central unit.
• the extraction solutions executed by the processing circuit can be for example:
• a second phenomenon related to lighting which can be produced by an object such as a vehicle in the direction of one or more sensors of the photovoltaic equipment of the system;
• the phenomenon to be considered takes into account the ambient light level and the detection system is configured to adapt the processing mode of the measured signal or of the measured signals according to the phenomenon to be detected.
• different processing modes is meant that the characteristic parameters of the measured signal to be detected may be different. 5 DD18780 AB
• Photovoltaic type sensors are indeed suitable tools for detecting the presence of an object (such as a vehicle) by the shading created by the object, this shading in fact causing a reduction in the irradiance on the sensor. .
• the presence of a shade on at least one photovoltaic sensor of the system causes a decrease in the electric production (in terms of current, power or both depending on the configuration of the sensor) as long as the shadow touches the sensor.
• This first phenomenon is dependent on the external irradiance supply and is therefore mainly operating during the day. However, it generally remains present and detectable at night thanks to the 0 luminous contribution of the stars and ambient lighting when it is present.
• the detection of the shading generated by the passage of the vehicle over at least one sensor of the photovoltaic equipment of the system can be carried out in different ways:
• the voltage across the sensor of the photovoltaic equipment is generally imposed by the application (which is generally a static converter) which therefore defines the current level resulting at maximum power0 IMPP.
• the parameter variation will therefore be easier to measure on the current than on the voltage. Indeed, the current remains the variable parameter because imposed only by the amount of radiation received.
• the system performs this monitoring using at least two separate sensors from the photovoltaic equipment, a first photovoltaic sensor C_pv_1 intended for measuring the short-circuit current and a second photovoltaic sensor C_pv_2 intended for measuring the voltage in circuit. open.
• the two measures can be time synchronized.
• the processing means can be common to the two sensors.
• monitoring the short-circuit current Icc is much more relevant for detection whereas it is much less at night.
• the sensor of equipment not used for detection can be used to charge the system battery.
• Figure 7 shows a power curve illustrating the passage of a vehicle5 on the photovoltaic equipment of the system.
• the time T3 at the end of the shading is also identified by the increase in the power produced.
• the level of production of the sensor when it is completely shaded i.e. the low level of the niche.
• This value should be considered compared to what should have been received in the absence of shading, which can be interpolated from other sensors of the equipment irradiated and not impacted by the shading or from the level of the niche when it is in its upper part.
• the presence of an object can be concluded when the voltage drops below a given threshold value.
• the second phenomenon detectable by a photovoltaic equipment sensor is linked to the clean lighting of a vehicle. Indeed, it can be seen that the light equipment of a vehicle (in particular the dipped or main beam headlights, but also the rear lights and the lighting of the license plate) generate an additional amount of light generating a significant response to the level of a system sensor. 5 Note that this second phenomenon can be measured with the same means as the first. On the other hand, the measurement is ideally based on the measurement of the open circuit voltage Voc, the latter being much more sensitive than the current in the event of weak radiation.
• the open circuit voltage makes it possible to detect and measure the passage of the vehicle via the light emitted by its headlights (dipped or / and road or / and fog lights and / and license plate rear lights), combined or not with a artificial light.
• the detection system becomes suitable for other applications, such as:
• the signature on the open circuit voltage Voc is here different from that which is observable during the day.
• the open circuit voltage Voc is low, or even zero, in the absence of lighting of the vehicle. Then the different characteristics of the curve are as follows:
• the voltage increases with a steeper slope, which corresponds to the passage of the vehicle above the system sensor.
• the voltage forms a positive peak, representative of the detection of the light generated essentially by the lighting of the license plate.
• the two phenomena i.e. detection of shading and detection of brightness by the sensor
• the first phenomenon is mainly observed during the day and the second occurs mainly at night. They are nevertheless easily uncorrelated when they occur simultaneously (the first generates in fact what corresponds to a drop in production at the level of the photovoltaic sensor compared to the basic level while the second generates what corresponds to an increase in the production).
• the passage of a vehicle can be announced. For example in the case of dawn or twilight, we could observe the case presented in Figure 8B, corresponding to the monitoring of the open circuit voltage Voc in low light. In this situation, the vehicle has its lights on. 5 In FIG. 8B, we thus:
• T 1 and T2 a distinction is made between the vehicle approach phase marked by an increase in open circuit voltage.
• a T5 corresponds to a positive peak, representative of the detection of the light generated essentially by the vehicle registration plate on the sensor. 5
• the open circuit voltage Voc here has the advantage of being extremely sensitive to light. So, in case the vehicle does not have its lights on DD18780 AB
• the measurement method can still detect the vehicle in a situation of twilight, dawn or the presence of artificial lighting (for example in the city).
• the great sensitivity of the system to the light of the license plate is noted, which even if it is weaker than that of the rear lights, is preponderant because it is oriented perpendicular to the sensor.
• the 0 associated time curve makes it possible to estimate several parameters:
• the detection of the presence of an object is revealed by a disturbance on the measurements of one or more monitored electrical quantities.
• the second phenomenon detection of brightness, for example the lights of a vehicle
• FIGS. 7 to 8B described above make it possible to illustrate the principle of presence detection.
• the disturbance takes the form of a slot more or less long depending on the length of the vehicle, its speed, ...
• the disturbance 5 is more akin to at least one negative peak (or double peak).
• FIG. 14B presents for example a measurement made during the passage of a cyclist.
• the detection time (the peak at T1) is much shorter than for a car.
• the minimum value reached by the slot is not as low as that which can be observed during the passage of a car.
• the disturbance comprises small successive peaks (and a lack of continuity).
• the reliability of the measurement will then depend essentially on the efficiency of the algorithm detecting the edges0 of the disturbance, and on the quality of coordination of the time stamping of the measurements.
• FIG. 9 illustrates a principle of embodiment of the system, allowing the determination of the speed of a vehicle.
• a first sensor C_pv_1 is formed of a first series of three photovoltaic panels connected in series and a second sensor C_pv_2 (advantageously identical to the first) is formed of a second series (identical to the first) of three photovoltaic panels connected in series, separated from the first series by a known distance along the length of the traffic lane.
• the same principle can be duplicated to occupy the entire width of the traffic lane.
• This configuration example makes it possible to easily measure the speed of the vehicle regardless of its size using the two sensors, by measuring the interval of 0 time between the start of the signature on the first sensor and the start of the signature on the second sensor and taking into account the distance D between the two sensors (known parameter).
• Figure 10 shows the power variation curves obtained on each of the two sensors.
• the distance D plotted on the time axis is there to show5 that the known distance between the two sensors C_pv_1, C_pv_2 makes it possible to estimate the speed of the vehicle thanks to the time offset measured between the responses of the series of panels.
• the speed of the object is then equal to the distance D between the sensors divided by the time of offset between the curves, regardless of the size of the vehicle.
• This principle can of course be transposed whatever the electrical magnitude0 monitored and whatever the phenomenon monitored (shading during the day, or voltage peak in open circuit at night).
• Figures 1 1 A and 1 1 B illustrate respectively the passage of a vehicle at night and the passage of a vehicle at dusk. In both cases, we notice the production of the same signal on each of the two sensors.
• T2 is worth around 700 ms (i.e. 0.0001944h).
• T 2 the time of the lower part of the slot (corresponding to the length 4.10m divided by the speed v of the vehicle) and T 3 the ascent time (corresponding to the illumination of the panel of 0.70m divided by the speed v of the vehicle).
• T 3 the ascent time (corresponding to the illumination of the panel of 0.70m divided by the speed v of the vehicle).
• the slot (observable in FIG. 13) consists successively of a power value at a high level, of a step of decrease (rapid, but not instantaneous) of the power, of a phase where the power is low, an ascent phase and a phase where the power is high.
• the time measurement Ti corresponds to the time at the ends of the descent phase. It must be equal to the time of DD18780 AB
• T2 can be defined, either from the start of the descent until the start of the ascent, or from the start of the low period until the end of the ascent.
• the length of the module will be taken into account if we consider the totality of the signature (do not take it into account if we consider only the low state).
• the shading will occur simultaneously on all the strings of the PV module without effect on the triggering of the bypass diodes (no steps observed in the fall of the current and in its ascent). The drop in current will therefore be close to a linear function over time.
• the length L of the vehicle can then be calculated from the following relation:
• Photovoltaic cells are semiconductors that are sensitive to temperature. It is known that the open circuit voltage Voc is more strongly influenced by temperature than the short-circuit current Icc. The photovoltaic cells could then be used to estimate the temperature directly5 at the level of the asphalt of the traffic lane: an advantage is to detect conditions of DD18780 AB
• the detection system is easy to set up; It can in particular be presented in the form of a one-piece element carrying all the components necessary for its operation (sensor, treatment, battery) in a limited space (in particular in thickness).
• the detection system may include a single sensor, sufficient to implement the features of the invention.
• the system is perfectly reliable; It allows object detection (especially of vehicles) under different operating conditions (day, night, high or low light).
• the system can be used in different types of traffic routes, including road, bicycle path, pedestrian crossing, underground parking ...
• the system makes it possible to determine a certain number of parameters, such as the presence of an object or of being alive, speed of the object or of the living being, length of the object, width of the object, temperature of the track, ... 5

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• 2018
  • 2018-08-08 FR FR1857392A patent/FR3084955A1/fr not_active Withdrawn
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  • 2019-08-07 WO PCT/FR2019/051911 patent/WO2020030877A2/fr unknown

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