FR3156967A1 - Method and system for securing the wearing of at least one piece of personal protective equipment - Google Patents

Abstract

Method and system for ensuring the safe wearing of at least one item of personal protective equipment The invention relates to a method for ensuring the safe wearing of at least one item of PPE by a worker (100), each item of PPE being equipped with a respective slave radiofrequency beacon (120). According to such a method, a master radiofrequency beacon (130) equipping the worker in a predetermined position performs, for each slave beacon: - reception of a radiofrequency signal emitted by the slave beacon; - estimation of the strength of the received signal; - estimation of a distance between the master beacon and the slave beacon based on the strength of the received signal; and, if the estimated distance is greater than a predetermined threshold distance associated with the slave beacon: - generation of a first alert information item. ABSTRACT FIGURE: [Fig. 1]

Description

Method and system for securing the wearing of at least one piece of personal protective equipment Field of invention

The field of invention is that of worker safety.

The invention relates more particularly to the wearing of personal protective equipment, or PPE, by such a worker.

The invention thus has numerous applications in all areas of intervention of workers wearing such PPE, in particular but not exclusively, for the maintenance of industrial systems such as distribution or telecommunications networks, renewable energy generation systems, waste management systems, etc.

Prior art and its drawbacks

PPE is designed to protect workers from occupational hazards, whether they are hazardous chemicals, extreme temperatures, airborne particles, excessive noise, or other potential hazards. However, despite the undeniable importance of PPE, wearing it can pose many challenges and problems.

First, there is a challenge in raising worker awareness of the importance of wearing PPE. It can be difficult to convince workers to wear it regularly, especially if it is perceived as uncomfortable or inconvenient. A poor understanding of occupational risks and potential health consequences can also lead to neglect of PPE.

Additionally, the choice of PPE is critical. Workers must be trained to select the appropriate PPE based on their specific work environment and the nature of the risks they are exposed to. Unsuitable PPE may not provide the necessary protection, which can jeopardize workers' health.

There is therefore a need for a technique to ensure that a worker actually wears PPE while working. Preferably, such a technique should ensure that the PPE worn by the worker is appropriate for a given work environment.

In one embodiment of the invention, a method is proposed for securing the wearing of at least one piece of personal protective equipment, hereinafter PPE, by a worker. Each PPE is equipped with a respective radiofrequency beacon, called a slave beacon. According to such a method, a radiofrequency beacon, called a master beacon, equipping the worker in a predetermined position performs, for each slave beacon:

- reception of a radiofrequency signal emitted by the slave beacon;

- an estimate of the power of the received signal;

- an estimate of a distance between the master beacon and the slave beacon from the power of the received signal; and, if the estimated distance is greater than a predetermined threshold distance associated with the slave beacon:

- generation of initial alert information.

Thus, the invention provides a new and inventive solution to ensure that a worker actually wears one (or more) PPE while working.

More specifically, the wearing of PPE equipped with a given slave beacon is controlled via the estimation of the distance between the master beacon and the given slave beacon. Thus, it is easily detected when the PPE in question is not worn by the worker.

In certain embodiments, if for each slave beacon the estimated distance is less than the predetermined threshold distance associated with the slave beacon, the master beacon executes again, for each slave beacon, said reception of a radiofrequency signal, said estimation of a power of the received signal, said estimation of a distance, and, if the new estimated distance is greater than the predetermined threshold distance associated with the slave beacon, the master beacon executes again the generation of a first alert information.

Thus, securing the wearing of PPE (or PPE) is carried out according to a predefined time sequence or periodically, e.g. with a period between 0.5 seconds and 1 second so as not to miss events such as the removal of PPE and not to have latency in the generation of alerts. In this way, it can be detected when the worker removes PPE, e.g. a glove, when this is not authorized.

In some embodiments, the master beacon performs, for each slave beacon, obtaining the predetermined threshold distance associated with the slave beacon.

Thus, the process is optimized for a given worker and given equipment.

In some embodiments, obtaining the predetermined threshold distance associated with the slave beacon comprises:

- reception of a calibration radiofrequency signal emitted by the slave beacon when the respective PPE is correctly positioned on the worker;

- an estimate of the power of the received calibration signal; and

- an estimate of the predetermined threshold distance associated with the slave beacon from the power of the calibration signal received.

In some embodiments, receiving a calibration radio frequency signal and estimating a power of the received calibration signal are performed a plurality of times so as to deliver a plurality of received calibration signal powers. The predetermined threshold distance associated with the slave beacon is estimated from an average of the received calibration signal powers.

Thus, the estimation of the predetermined threshold distance associated with the slave beacon is more precise via the averaging effect which reduces the variance of the estimation in the presence of noise.

In some embodiments, the master tag executes, for each slave tag:

- reception of a radiofrequency identification signal emitted by the slave beacon, the identification signal comprising a predefined identifier stored in the slave beacon, the predefined identifier being associated with the type of PPE that the slave beacon is equipped with;

- a transmission, to a radiofrequency beacon, called a tracking beacon, implemented in a worker's work area, of the predefined identifier stored in the slave beacon, the correspondence between the predefined identifier and the associated type of PPE being known to the tracking beacon.

Thus, the tracking beacon is able to check that the worker is wearing the PPE (or PPE) to be used in the work area.

In some embodiments, the master tag performs:

- a reception of a second alert information sent by the tracking beacon when, for at least one expected identifier associated with a type of PPE to be worn by the worker in the work area, no predefined identifier transmitted during the execution, for each slave beacon, of said transmission corresponds to the expected identifier.

In certain embodiments, the master beacon executes a sending of the first alert information and/or the second alert information to a restitution device equipping the worker.

This alerts the worker that he is not wearing the expected PPE, or that he is wearing the wrong type of PPE for the work area he is in.

In some embodiments, the radio frequency communication between the master beacon and the at least one slave beacon implements a radio technology belonging to the group comprising:

- a Bluetooth protocol;

- a WiFi protocol;

- a Zigbee protocol; and

- an Ultra WideBand protocol.

In some embodiments, the radio frequency communication between the master beacon and the tracking beacon implements a radio technology belonging to the group comprising:

- a Bluetooth protocol;

- a WiFi protocol;

- a Zigbee protocol;

- an Ultra WideBand protocol; and

- a modulation called OOK.

The invention also relates to a radiofrequency beacon, called a master beacon, for securing the wearing of at least one PPE by a worker. Each PPE is equipped with a respective radiofrequency beacon, called a slave beacon. The master beacon is configured to execute, for each slave beacon and when the master beacon equips the worker in a predetermined position:

- reception of a radiofrequency signal emitted by the slave beacon;

- an estimate of the power of the received signal;

- an estimate of a distance between the master beacon and the slave beacon from the power of the received signal; and, if the estimated distance is greater than a predetermined threshold distance associated with the slave beacon:

- generation of initial alert information.

The invention also relates to a system comprising:

- a radio frequency beacon, called a master beacon, as described above; and

- at least one radiofrequency beacon, called a slave beacon, intended to equip a respective PPE.

List of figures

Other aims, characteristics and advantages of the invention will appear more clearly on reading the following description, given as a simple illustrative, and non-limiting, example, in relation to the figures, among which:

FIG. 1 illustrates a system for securing the wearing of PPE by a worker according to one embodiment of the invention;

FIG. 2 illustrates an example of the structure of a radiofrequency beacon, called a slave beacon, of the system of the FIG. 1 according to one embodiment of the invention;

FIG. 3 illustrates an example of the structure of a radiofrequency beacon, called a master beacon, of the system of the FIG. 1 according to one embodiment of the invention;

FIG. 4 illustrates an example of the structure of a radiofrequency beacon, called a tracking beacon, of the system of the FIG. 1 according to one embodiment of the invention;

FIG. 5 illustrates an analog signal representing a bitstream according to one embodiment of the invention;

FIG. 5 illustrates a radio frequency carrier according to one embodiment of the invention;

FIG. 5 illustrates the signal resulting from the OOK modulation of the carrier of the FIG. 5 by the binary train of the FIG. 5 according to one embodiment of the invention.

FIG. 6 illustrates the steps of a process for securing the wearing of PPE by the worker implemented by the system of the FIG. 1 according to one embodiment of the invention.

Detailed description of embodiments of the invention

We now present, in relation to the FIG. 1, a system for securing the wearing of PPE 110a, 110b, 110c by a worker 100 according to an embodiment of the invention. For example, such PPE 110a, 110b, 110c comprise safety shoes 110a, gloves 110b and a helmet 110c.

The security system comprises a set of radiofrequency beacons 120, called slave beacons. Each slave beacon equips a respective PPE 110a, 110b, 110c. In the present embodiment, the worker 100 wears a plurality of PPEs 110a, 110b, 110c each equipped with a respective slave beacon 120. In other embodiments, the worker 100 wears a single PPE equipped with a slave beacon 120. In general, the security system, as well as the corresponding method of the FIG. 6 , concerns the wearing of at least one PPE by a worker 100, each PPE being equipped with a respective slave beacon 120.

Back to the FIG. 1 , the security system also comprises a radiofrequency beacon 130, called master beacon, equipping the worker 100 in a predetermined position. The fact that the master beacon 130 is placed in a predetermined position allows, for each slave beacon 120, a comparison between, on the one hand, the estimated distance between the master beacon 130 and the slave beacon 120 considered and, on the other hand, a predetermined threshold distance associated with the slave beacon 120 considered. Such a comparison is more particularly described below in relation to [Fig.5].

Back to the FIG. 1 , the security system also comprises a radiofrequency beacon 150, called a tracking beacon, implemented in a work area 160 of the worker 100 (e.g. a warehouse, a given workstation, a construction site). Such a tracking beacon 150 makes it possible in particular to check that the worker 100 is wearing the PPE 110a, 110b, 110c to be used in the work area 160. However, in other embodiments the security system does not comprise a tracking beacon 150. In such cases, the security system only comprises a master beacon 130 equipping the worker 100 in a predetermined position and one (or more) slave beacons 120 equipping a respective PPE 110a, 110b, 110c.

Back to the FIG. 1 , the security system also comprises a restitution device 140. Such a restitution device 140 comprises means (e.g. a radiofrequency transceiver or a wired link) for communicating with the master beacon 130 so as to receive one (or more) alert information. The restitution device 140 also comprises restitution means (e.g. a loudspeaker, a screen, a light device) to the worker 100 of the alert information (or information). However, in other embodiments the security system does not comprise a restitution device 140. The alerts generated by the master beacon 130 are for example sent to a remote device, e.g. to inform a manager of the worker 100.

We now present, in relation to the FIG. 2an example of a slave tag structure 120 comprising means for implementing all or part of the corresponding steps of the method for securing theFIG. 6according to one embodiment of the invention.

More particularly, such a slave tag 120 comprises different means such as a random access memory 203 (for example a RAM memory), a processing unit 202 equipped for example with a processor, and controlled by a computer program stored in a read-only memory 201 (for example a ROM memory or a hard disk). Upon initialization, the code instructions of the computer program are for example loaded into the random access memory 203 before being executed by the processor of the processing unit 202.

The slave beacon 120 further comprises an on-board electrical energy source 205 (e.g. a battery, rechargeable or not) and radio frequency communication means 204, e.g. a transmitter/receiver implementing a protocol of the Bluetooth, Zigbee or UWB (for “Ultra WideBand” in English) type. Such communication means 204 allow communications e.g. with the master beacon 130.

This FIG. 2 illustrates only one particular way, among several possible ones, of producing the slave tag 120 so that it carries out all or part of the corresponding steps of the method of securing the FIG. 6 (according to any of the embodiments and/or variants described below in relation to the FIG. 6 ). For example, these steps can be performed either by implementing a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or by implementing a dedicated computing machine (for example a set of logic gates such as an FPGA or an ASIC, or any other hardware module).

In the case where the slave tag 120 is produced by implementing a reprogrammable computing machine, the corresponding program (i.e. the sequence of instructions) may be stored in a removable storage medium (such as for example a CD-ROM, a DVD-ROM, a USB key) or not, this storage medium being partially or totally readable by a computer or a processor.

We now present, in relation to the FIG. 3an example of a master tag structure 130 comprising means for implementing all or part of the corresponding steps of the method for securing theFIG. 6according to one embodiment of the invention.

More particularly, such a master tag 130 comprises different means such as a random access memory 303 (for example a RAM memory), a processing unit 302 equipped for example with a processor, and controlled by a computer program stored in a read-only memory 301 (for example a ROM memory or a hard disk). Upon initialization, the code instructions of the computer program are for example loaded into the random access memory 303 before being executed by the processor of the processing unit 302.

The master tag 130 further comprises an on-board electrical energy source 305 (e.g. a battery, rechargeable or not) and radio frequency communication means 304, e.g. a transmitter/receiver implementing a protocol of the Bluetooth, WiFi, Zigbee or UWB (for “Ultra WideBand” in English) type. Such communication means 204 allow communication e.g. with the slave tag(s) 120 and with the tracking tag 150. In certain embodiments, in order to communicate with the tracking tag 150, the radio frequency communication means 304 implement a so-called all-or-nothing modulation, or OOK (for “On-Off Keying” in English). More particularly, according to such a modulation, an analog signal representing a binary train ( FIG. 5) comes to modulate the amplitude of a radiofrequency carrier ( FIG. 5) in all or nothing. For example, a low state information bit (logic “0”) corresponds to a substantially zero amplitude of the carrier while a high state information bit (logic “1”) corresponds to a non-zero predetermined value amplitude of the carrier ( FIG. 5).

There FIG. 3 illustrates only one particular way, among several possible ones, of producing the master tag 130 so that it carries out all or part of the corresponding steps of the method of securing the FIG. 6 (according to any of the embodiments and/or variants described below in relation to the FIG. 6 ). For example, these steps can be performed either by implementing a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or by implementing a dedicated computing machine (for example a set of logic gates such as an FPGA or an ASIC, or any other hardware module).

In the case where the master tag 130 is produced by implementing a reprogrammable computing machine, the corresponding program (i.e. the sequence of instructions) may be stored in a removable storage medium (such as for example a CD-ROM, a DVD-ROM, a USB key) or not, this storage medium being partially or totally readable by a computer or a processor.

We now present, in relation to the FIG. 4an example of a tracking beacon structure 150 comprising means for implementing all or part of the corresponding steps of the method for securing theFIG. 6according to one embodiment of the invention.

More particularly, such a tracking beacon 150 comprises various means such as a random access memory 403 (for example a RAM memory), a processing unit 402 equipped for example with a processor, and controlled by a computer program stored in a read-only memory 401 (for example a ROM memory or a hard disk). Upon initialization, the code instructions of the computer program are for example loaded into the random access memory 403 before being executed by the processor of the processing unit 402.

The tracking beacon 150 further comprises an on-board electrical energy source 405 (e.g. a battery, rechargeable or not) and radio frequency communication means 404, e.g. a transmitter/receiver implementing a protocol of the Bluetooth, WiFi, Zigbee or UWB (for “Ultra WideBand”) type. Such communication means 404 allow communication e.g. with the master beacon 130. In certain embodiments, the communication means 404 implement a so-called all-or-nothing modulation, or OOK (for “On-Off Keying”), as described above.

There FIG. 4 illustrates only one particular way, among several possible ones, of producing the tracking beacon 150 so that it carries out all or part of the corresponding steps of the method of securing the FIG. 6 (according to any of the embodiments and/or variants described below in relation to the FIG. 6 ). For example, these steps can be performed either by implementing a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or by implementing a dedicated computing machine (for example a set of logic gates such as an FPGA or an ASIC, or any other hardware module).

In the case where the tracking beacon 150 is produced by implementing a reprogrammable computing machine, the corresponding program (i.e. the sequence of instructions) may be stored in a removable storage medium (such as for example a CD-ROM, a DVD-ROM, a USB key) or not, this storage medium being partially or totally readable by a computer or a processor.

We now present, in relation to the FIG. 6, the steps of a process for securing the wearing of PPE 110a, 110b, 110c implemented by the system of theFIG. 1according to one embodiment of the invention.

According to such a method, the master beacon 130 executes, for each slave beacon 120, a step E600 of obtaining a predetermined threshold distance associated with the slave beacon 120 considered. More particularly, such a predetermined threshold distance is representative of the radioelectric distance between the master beacon 130 and the slave beacon 120 considered when the corresponding PPE 110a is correctly positioned on the worker 100. The predetermined threshold distance can thus be interpreted as a metric making it possible to decide whether the PPE 110a, 110b, 110c in question is actually correctly positioned on the worker 100.

In some embodiments, obtaining the predetermined threshold distance associated with a given slave beacon 120 comprises the following steps performed by the master beacon 130:

- reception of a calibration radiofrequency signal emitted by the slave beacon 120 considered when the corresponding PPE 110a, 110b, 110c is correctly positioned on the worker 100;

- an estimate of the power of the received calibration signal; and

- an estimate of the predetermined threshold distance associated with the slave beacon 120 considered from the power of the calibration signal received.

For example, the correspondence between the predetermined threshold distance and power of the received calibration signal is given by the equation [Math.1] when the powers are expressed in logarithmic units:

Or represents the transmission power of the slave beacon 120 considered and a constant which depends on the radio propagation medium (eg for the void).

In some embodiments, the steps of receiving a calibration radiofrequency signal and estimating a power of the received calibration signal are executed a plurality of times so as to deliver a plurality of powers of received calibration signals. The predetermined threshold distance associated with the slave beacon 120 considered is then estimated from an average of the powers of received calibration signals.

Thus, the estimation of the predetermined threshold distance associated with the slave beacon 120 considered is more precise via the averaging effect which reduces the variance of the estimation in the presence of noise.

In other embodiments, the predetermined threshold distance associated with a given slave tag 120 is obtained by other techniques, e.g. based on estimates made from a worker model, or from electromagnetic simulations.

Back to the FIG. 6 , the master tag 130 executes, for each slave tag 120:

- a step E610 of receiving a radiofrequency signal emitted by the slave beacon 120 considered. The radiofrequency signal in question is identified by the master beacon 130 as being emitted by the slave beacon 120 considered. For example, the radiofrequency signal in question comprises an identifier of the slave beacon 120 considered. Alternatively, a communications channel between the master beacon 130 and the slave beacon 120 considered is previously established according to a given radio protocol;

- a step E620 of estimating the power of the received signal;

- a step E630 of estimating a distance between the master beacon 130 and the slave beacon 120 considered from the power of the received signal; and, if the estimated distance is greater than the predetermined threshold distance associated with the slave beacon 120 considered:

- a step E640 for generating a first alert information.

For example, during step E630, the distance between the master beacon 130 and the slave beacon 120 considered is estimated by implementing the same steps as those described above in relation to step E600 of obtaining a predetermined threshold distance associated with the slave beacon 120 considered (e.g. by implementing the equation [Math.1] and possibly averaging).

In the embodiment of the FIG. 6 , the predetermined threshold distance associated with the slave beacon 120 considered is the threshold distance determined during the execution of the aforementioned step E600.

However, in certain embodiments, step E600 is not executed and the predetermined threshold distance associated with the slave beacon 120 considered is a threshold distance previously configured e.g. on the basis of previous implementations of step E600.

Regardless of the method of obtaining the predetermined threshold distance associated with a given slave beacon 120, the wearing of a PPE 110a, 110b, 110c equipped with such a slave beacon 120 is controlled via the estimation of the distance between the master beacon 130 and the given slave beacon 120. Thus, it is easily detected if one (or more) PPE 110a, 110b, 110c is not worn by the worker 100. The present technique thus makes it possible to ensure that the worker 100 actually wears one (or more) PPE 110a, 110b, 110c during his work.

Back to the FIG. 6 , if for each slave beacon 120 the estimated distance is less than the predetermined threshold distance associated with the slave beacon 120 in question, the master beacon 130 executes again, for each slave beacon 120: the step E610 of receiving a radiofrequency signal, the step E620 of estimating a power of the received signal, the step E630 of estimating a distance between the master beacon 130 and the slave beacon 120 considered. If the new estimated distance is greater than the predetermined threshold distance associated with the slave beacon 120 considered, the master beacon 130 executes again the step E640 of generating a first alert information.

Thus, securing the wearing of PPE 110a, 110b, 110c is carried out according to a predefined time sequence or periodically, e.g. with a period between 0.5 seconds and 1 second. This makes it possible, for example, not to miss events such as the removal of PPE and to avoid latency in the generation of alerts. In this way, it can be detected when the worker 100 removes PPE 110a, 110b, 110c, e.g. a glove, during his work when this is not authorized.

In the embodiment of the FIG. 6 , the master tag 130 executes, for each slave tag 120:

- a step E650 of receiving a radiofrequency identification signal emitted by the slave beacon 120 in question. The identification signal comprises a predefined PPE type identifier stored in the slave beacon 120 in question. The predefined PPE type identifier being associated with the type of PPE 110a, 110b, 110c that the slave beacon 120 in question is equipped with. For example, such a PPE type identifier can take a first value associated with the “glove” type, a second value associated with the “safety shoe” type, a third value associated with the “helmet” type, etc. The PPE type identifier is for example programmed in the slave beacon 120 at the time of its implementation in the corresponding PPE 110a, 110b, 110c or at the time of a calibration phase of the overall system;

- a step E660 of transmitting, to the tracking beacon 150 implemented in the work zone 160, the predefined PPE type identifier stored in the slave beacon 120 considered.

The correspondence between the predefined PPE type identifier and the associated PPE type 110a, 110b, 110c is known to the tracking tag 150.

Thus, the tracking beacon 150 is able to check that the worker 100 is wearing the PPE 110a, 110b, 110c to be used in the work zone 160. To do this, the tracking beacon 150 performs e.g. a comparison of the predefined PPE type identifier transmitted by the master beacon 130 with one (or more) expected identifiers corresponding to the types of PPE to be worn in the work zone 160 in which the tracking beacon 150 is implemented.

For example, when, for at least one expected identifier associated with a type of PPE to be worn in the work area 160, no predefined identifier transmitted by the master tag 130 during the execution, for each slave tag 120, of the transmission step E660 corresponds to the expected identifier, the tracking tag 150 generates a second alert information. To do this, the tracking tag 150 e.g. compares, to a predetermined list of expected identifiers of types of PPE to be worn in the work area 160, each predefined identifier received during the execution of the step E660. The tracking tag 150 detects, for each expected identifier, whether a predefined identifier received during the execution of the step E660 corresponds to the expected identifier. For example, if for at least one expected identifier, no predefined identifier received during the execution of step E660 corresponds to the expected identifier in question, the tracking beacon 150 generates the second alert information, e.g. after a predetermined time duration.

In this case, during a step E670 , the tracking beacon 150 transmits the second alert information to the master beacon 130. Conversely, during the step E670, the master beacon 130 receives the second alert information.

However, in other embodiments, steps E650, E660 and E670 are not implemented, eg when the work area 160 does not include a tracking beacon 150 as described above in relation to the FIG. 1 .

Back to the FIG. 6 , during a step E680 , the master beacon 130 executes a sending of the first alert information and/or the second alert information to the restitution device 140 equipping the worker 100.

Thus, worker 100 is alerted that he is not wearing one (or more) PPE 110a, 110b, 110c, or that he is wearing one (or more) PPE 110a, 110b, 110c of the wrong type for the work zone 160 in which he is located.

In certain embodiments described above in connection with the FIG. 1 in which the security system does not include a restitution device 140, step E680 is not necessarily implemented. For example, the alert information (or information) is stored in the master tag 130 in order to generate a history of the problems that have occurred, e.g. for post-processing purposes. Alternatively, during step E680 the master tag 130 sends the alert information (or information) to a remote device, e.g. to inform a manager of the worker 100.

In certain embodiments, the radio frequency communication between the master beacon 130 and the slave beacon(s) 120 implements a radio technology belonging to the group comprising: a Bluetooth protocol, a WiFi protocol, a Zigbee protocol and a UWB protocol.

In certain embodiments, the radio frequency communication between the master beacon 130 and the tracking beacon 150 implements a radio technology belonging to the group comprising: a Bluetooth protocol, a WiFi protocol, a Zigbee protocol, a UWB protocol and a so-called OOK modulation as described above.

Claims (12)

Method for securing the wearing of at least one piece of personal protective equipment (110a, 110b, 110c), hereinafter PPE, by a worker (100), each PPE being equipped with a respective radiofrequency beacon (120), called slave beacon,
characterized in that a radiofrequency beacon (130), called master beacon, equipping the worker in a predetermined position executes, for each slave beacon:
- reception (E610) of a radiofrequency signal emitted by the slave beacon;
- an estimate (E620) of the power of the received signal;
- an estimate (E630) of a distance between the master beacon and the slave beacon from the power of the received signal; and, if the estimated distance is greater than a predetermined threshold distance associated with the slave beacon:
- a generation (E640) of a first alert information.
Method according to claim 1, in which, if for each slave beacon the estimated distance is less than the predetermined threshold distance associated with the slave beacon, the master beacon executes again, for each slave beacon, said reception of a radiofrequency signal, said estimation of a power of the received signal, said estimation of a distance, and, if the new estimated distance is greater than the predetermined threshold distance associated with the slave beacon, the master beacon executes again the generation of a first alert information.
Method according to claim 1 or 2, in which the master tag executes, for each slave tag:
- obtaining (E600) the predetermined threshold distance associated with the slave beacon.
The method of claim 3, wherein obtaining the predetermined threshold distance associated with the slave beacon comprises:
- reception of a calibration radiofrequency signal emitted by the slave beacon when the respective PPE is correctly positioned on the worker;
- an estimate of the power of the received calibration signal; and
- an estimate of the predetermined threshold distance associated with the slave beacon from the power of the calibration signal received.
The method of claim 4, wherein said receiving a calibration radio frequency signal and said estimating a power of the received calibration signal are performed a plurality of times so as to deliver a plurality of powers of received calibration signals,
and wherein the predetermined threshold distance associated with the slave beacon is estimated from an average of the received calibration signal powers.
Method according to any one of claims 1 to 5, in which the master tag executes, for each slave tag:
- a reception (E650) of a radiofrequency identification signal emitted by the slave beacon, the identification signal comprising a predefined identifier stored in the slave beacon, the predefined identifier being associated with the type of PPE that the slave beacon equips;
- a transmission (E660), to a radiofrequency beacon (150), called a tracking beacon, implemented in a work zone (160) of the worker, of the predefined identifier stored in the slave beacon, the correspondence between the predefined identifier and the associated type of PPE being known to the tracking beacon.
The method of claim 6, wherein the master tag performs:
- a reception (E670) of a second alert information sent by the tracking beacon when, for at least one expected identifier associated with a type of PPE to be worn by the worker in the work zone, no predefined identifier transmitted during the execution, for each slave beacon, of said transmission corresponds to the expected identifier.
A method according to any one of claims 1 to 7, wherein the master tag performs:
- sending (E680) the first alert information and/or the second alert information to a restitution device (140) equipping the worker.
Method according to any one of claims 1 to 8, in which the radio frequency communication between the master beacon and the at least one slave beacon implements a radio technology belonging to the group comprising:
- a Bluetooth protocol;
- a WiFi protocol;
- a Zigbee protocol; and
- an Ultra WideBand protocol.
Method according to claim 6 or 7, in which the radio frequency communication between the master beacon and the tracking beacon implements a radio technology belonging to the group comprising:
- a Bluetooth protocol;
- a WiFi protocol;
- a Zigbee protocol;
- an Ultra WideBand protocol; and
- a modulation called OOK.
radiofrequency beacon (130), called master beacon, for securing the wearing of at least one piece of personal protective equipment (110a, 110b, 110c), hereinafter PPE, by a worker (100), each PPE being equipped with a respective radiofrequency beacon (120), called slave beacon,
characterized in that the master tag is configured to execute, for each slave tag and when the master tag equips the worker in a predetermined position:
- reception (E610) of a radiofrequency signal emitted by the slave beacon;
- an estimate (E620) of the power of the received signal;
- an estimate (E630) of a distance between the master beacon and the slave beacon from the power of the received signal; and, if the estimated distance is greater than a predetermined threshold distance associated with the slave beacon:
- a generation (E640) of a first alert information.
System comprising:
- a radiofrequency beacon (130) according to claim 11; and
- at least one radiofrequency beacon (120), called a slave beacon, intended to equip a respective PPE.