Patent ID: 12227302

DETAILED DESCRIPTION

The figures are presented for indicative purposes and in no way limit the invention. Unless stated otherwise, a same element appearing in the different figures has a single reference.

A first aspect of the invention illustrated in [FIG.1] relates to an autonomous impact detection device3.

The device3according to a first aspect of the invention comprises at least one impact detector DC. The impact detector DC may for example be chosen from among an accelerometer or instead a piezoelectric sensor. In one embodiment, the device3comprises a plurality of impact detectors DC, the nature of the detectors DC of the plurality of detectors DC being able to be identical or different. Thus, it is possible to put in place a system of redundancy of measurements in order to ensure the exactitude thereof, by choosing for example detectors of same nature. It is also possible to choose detectors of different nature, each type of detector being able to be sensitive to different signals.

The device3according to a first aspect of the invention also comprises at least one wireless transmission means MC provided with an antenna AN configured to transmit the information collected by the impact detector or detectors DC. The wireless transmission means MC may for example be an RFID type communication means, a 4G communication means, a Wifi communication means or instead a WAIC (Wireless Avionics Intra-Communications) communication means. The wireless communication means MC make it possible to transmit the data measured by the impact detector or detectors DC rapidly, which presents a certain advantage when the collection of data has to be done regularly and/or on a large number of devices3according to a first aspect of the invention. This further guarantees a freedom of implantation of the detection device3according to the invention since the latter does not require any physical connection to transmit the measured data.

The device3according to a first aspect of the invention also comprises at least one energy storage means MS configured to supply the impact detector DC and the wireless transmission means MC with energy. In one embodiment, the storage means MS is chosen among a battery, a capacitance or instead a supercapacitance.

The device3according to a first aspect of the invention also comprises at least one Seebeck module GE. Generally speaking, a Seebeck module GE comprises one or more Seebeck cells CE such as illustrated inFIG.2and comprising a first surface S1intended to be exposed to a first temperature T1and a second surface S2intended to be exposed to a second temperature T2. The temperature gradient ΔT applied to the Seebeck module GE is equal to the difference between the temperature T2to which the second surface S2of the Seebeck cell CE is exposed and the temperature T1to which the first surface S1of the Seebeck cell CE is exposed such that ΔT=T2-T1. The presence of this temperature gradient ΔT leads to the appearance of a voltage V at the terminals of the Seebeck cell CE, the sign of this voltage V being a function of the sign of the gradient ΔT applied to the Seebeck cell and the Seebeck coefficient of the materials used. Hereafter, by convention, a positive gradient ΔT>0 will lead to the appearance of a positive voltage V>0 and a negative gradient ΔT<0 will lead to the appearance of a negative voltage V<0.

An exemplary embodiment of a Seebeck module GE according to the invention is illustrated inFIG.3wherein the Seebeck module GE is fixed on the inner surface S1of a wall10, for example the fuselage of an airplane, so as to benefit from the temperature difference between an internal temperature Tintand an external temperature Text. For example, in the case of an aircraft, a substantial temperature difference exists during flight phases or instead during storage phases in conditions of high external temperatures. More particularly, the Seebeck module GE comprises a Seebeck cell CE comprising a first surface S1and a second surface S2and a radiator RA fixed on the second surface S2of the Seebeck cell. In addition, the radiator RA comprises fins enabling efficient thermalisation of the second surface S2of the Seebeck cell CE. In this example, the first surface S1of the Seebeck cell is fixed at the level of the inner surface S1of a wall10, for example the inner surface of the fuselage of an aircraft. This fixation is preferentially carried out using an adhesive AD which is a good heat conductor so as to ensure good thermalisation of the first surface S1of the Seebeck cell in contact with the inner surface of the wall10. In this configuration, the temperature gradient ΔT applied to the Seebeck module is thus equal to the difference between the temperature T2of the second face S2of the Seebeck cell CE and the temperature T1of the first face S1of the Seebeck cell CE. For example, if the wall10is the fuselage of an aircraft, during the flight phase, the temperature T1of the first surface is generally comprised between −20° C. and −30° C., or even in extreme cases −50° C. to −60° C., whereas the temperature T2of the second surface is in general equal to 0° C. due to the presence of the radiator. Thus, during the flight phase, the temperature gradient ΔT applied to the Seebeck module is thus generally comprised between 20° C. and 60° C. Given these temperature ranges and a power requirement of the order of several tens of mW, a Seebeck cell CE of several tens of millimetres, for example 40×40 mm, may be sufficient. As an example, the table below illustrates the charging times of a storage means MS (the left column representing the capacitance of the storage means in Farads noted C(F)) as a function of time and the temperature gradient ΔT applied to a Seebeck module.

TABLE 1ΔT (° C.)C (F)5101520253040500.531 min7 min3 min104 s64 s43 s22 s13 s162 min15 min6 min3 min2 min85 s44 s26 s2125 min30 min13 min7 min4 min3 min89 s52 s3187 min45 min19 min10 min6 min4 min2 min78 s

In one embodiment illustrated inFIG.4, the device according to a first aspect of the invention comprises a second Seebeck module GE2configured in an inversed manner compared to the Seebeck module described previously, hereafter first Seebeck module GE1. In other words, given that a Seebeck cell CE comprises a first surface S1and a second surface S2, when the device3according to a first aspect of the invention is fixed to a surface, the Seebeck cell CE of the first Seebeck module GE1is in contact with this surface10through its first surface S1whereas the Seebeck cell CE of the second Seebeck module GE2is in contact with said surface10through its second surface S2. In other words, in the example illustrated inFIG.4and for the second Seebeck module GE2, the radiator RA is fixed on the first surface S1of the Seebeck cell CE and the second surface S2of the Seebeck cell CE is fixed at the level of the inner surface of the wall10. In this embodiment, the device3according to a first aspect of the invention is thus able to produce a positive (or negative) voltage whatever the sign of the temperature gradient ΔT between the internal temperature Tintand the external temperatureText. InFIG.4, the dashed arrow indicates, for each Seebeck cell CE, the sense of the temperature gradient required to obtain a positive voltage V at the terminals of the corresponding Seebeck module.

In one embodiment illustrated inFIG.5, the device1according to a first aspect of the invention comprises an energy supervisor SE configured to distribute energy to the different components of the device3according to a first aspect of the invention.

In one embodiment illustrated inFIG.6, the wireless transmission means MC/RF are also configured to receive energy by radio frequency. Thus, when the Seebeck module GE has not enabled a sufficient charge of the storage means MS, the latter may be recharged remotely and/or the different components of the device3may be supplied with energy. Thus, the wireless transmission means MC/RF represent a complementary means for supplying the Seebeck module GE with energy. Indeed, when the temperature gradient is not sufficient and when the Seebeck module GE thus cannot supply the device3according to a first aspect of the invention, the wireless transmission means MC/RF may be used as a substitute for the Seebeck module GE. It will be noted that this is particularly advantageous in the case of an aircraft1since small gradients are generally observed when the aircraft1is on the ground. Yet, it is precisely when the aircraft1is parked on the ground that security measures allow the transmission of radio frequencies capable of supplying the necessary energy to the device3.

In one embodiment illustrated inFIG.7, the device3according to a first aspect of the invention comprises a memory MM configured to store the measurements made by the impact detector or detectors DC. Thus, the measurements made by the device3are not necessarily transmitted immediately, but only at regular intervals. In this embodiment, the device3according to a first aspect of the invention also comprises a computing means CP coupled to the memory MM, said computing means CP being configured to perform a pre-processing or a processing of the data acquired by the impact detector or detectors DC. For example, the pre-processing or the processing will be able to comprise the selection of acquired data which have to be memorized in the memory MM and/or transmitted by the wireless communication means MC.

In one embodiment illustrated inFIG.8, the device3according to a first aspect of the invention comprises a first set31, for example in the form of a first housing, comprising the impact detector or detectors DC, and a second set32, for example in the form of a second housing, comprising the Seebeck module or modules GE, the first set31and the second set32being connected such that the energy generated by the Seebeck module GE at the level of the second set32can be transmitted to the first set31. Thus, it is possible to displace the Seebeck module or modules when the most suitable location for the detection of impacts and the most suitable location for the generation of energy by the Seebeck module GE are not identical.

A second aspect of the invention relates to a system for detecting impacts on a structure, the detection system comprising a plurality of autonomous detection devices3according to a first aspect of the invention positioned on a surface S1of the structure, each detection device3being associated with an identifier relating to a predetermined zone of the structure; and a plurality of communication devices close to the structure and configured to communicate with the detection devices3of the plurality of detection devices3so as to collect the measurements made by said devices3and to associate them with the identifier of the corresponding device3.

In the remainder of the description, the system according to a second aspect of the invention is going to be illustrated through an application wherein the structure to monitor is the fuselage of an aircraft. Those skilled in the art will understand that such a system may be used in other situations. Consequently, a third aspect of the invention illustrated inFIG.9relates to an aircraft1comprising a fuselage10and an impact detection system according to a second aspect of the invention. The detection system comprises a plurality of autonomous detection devices3according to a first aspect of the invention positioned on an inner surface S1of the fuselage10of the aircraft1. Further, each autonomous detection device3is associated with an identifier relating to a predetermined fuselage zone10, such that it is possible, knowing the identifier of the device3having detected an impact, to know the zone in which the impact has occurred.

In one embodiment, the detection devices3are fixed on the inner surface S1of the fuselage10using an adhesive. The use of an adhesive enables an easy positioning and repositioning of the detection devices3. In addition, such a fixation means reduces the risks of damaging the fuselage10during the fixation of said detection devices3.

The aircraft1according to a third aspect of the invention also comprises a plurality of communication devices4arranged in the aircraft1and configured to communicate with the detection devices3of the plurality of detection devices3so as to collect the measurements made by said devices3and to associate them with the identifier of the corresponding device3. Preferably, the plurality of communication devices4are positioned so as to be able to communicate with all of the detection devices3of the plurality of detection devices3. It is important to note that a communication device4will be able to communicate with one or more detection devices3. It is also important to note that one or more detection devices3may be positioned so as not to be able to communicate with any of the communication devices4. The latter will however be able to be interrogated using a portable communication device4′, for example during control or maintenance operations.

In one embodiment, the communication devices4are supplied by an electrical supply network12′ connecting the different communication devices4to the electrical supply of the aircraft1. The energy thus received may then be transmitted to each detection device3through the means for receiving energy by radio frequency RF. To do so, each communication device4comprises a wireless communication means MC′/RF′ configured to operate as wireless communication means or as means for sending energy by radio frequency to the detection devices3. Assuming a communication device4having an antenna AN′ of gain equal to 3 dBi and a loss due to the cable of 4.4 dB, and an autonomous detection device3having an antenna AN having a gain equal to 4.5 dBi, table2below illustrates the power transmitted (in dBm and in W) and the power received at the level of a detection device3(in dBm and in mVV) as a function of the distance separating the considered communication device4from the considered detection device3.

TABLE 2PowerPowerPowerPowertransmittedtransmittedreceivedreceivedDistance(dBm)(W)(dBm)(mW)1m3324.93.13m332−4.60.345m332−9.10.1210m332−15.10.031

Those skilled in the art will thus ensure to take this information into account during the positioning of the communication devices4and/or the positioning of the detection devices3, while obviously adapting the hypotheses made above.

In one embodiment illustrated inFIG.10, each communication device4comprises an energy storage means MS′, for example a battery, configured to supply the communication device4when the electrical supply network12′ no longer supplies energy. This is notably the case when the aircraft1is parked for a long period. Thus, even without external electrical supply, the communication devices4of the aircraft1can continue to interrogate the detection devices3, or even to supply the detection devices3by radio frequency if necessary. In one embodiment, the communication device4also comprises an energy supervisor SE′ in charge of the management of the energy of the communication device4, and in particular of the energy storage means MS′.

In the same way, the communication devices4are connected to a communication network12and the data collected from the detection devices3by the communication devices4may be transmitted on the communication network12to next be processed, for example by an on-board computer5or instead by a centralised maintenance server. In one embodiment, each communication device4comprises a memory MM′ (e.g. a hard disc), the data collected from the detection devices3being stored in the memory MM′ when the electrical supply network12′ no longer supplies energy, then transmitted on the communication network when the electrical supply network12′ again supplies energy. In one embodiment, the communication device4comprises a computing means CP′ (for example a processor) making it possible to process the data stored in the memory MM′.

In one embodiment, the fuselage10is a composite fuselage. Indeed, composite fuselage damage is particularly difficult to detect by visual inspection and a detection system such as described in the second aspect of the invention makes this detection much more reliable. It follows however from the above that the invention may be implemented on any type of fuselage (made of composite materials, metal materials, etc.).