TIRE CASING FITTED WITH A MEASUREMENT SYSTEM AND METHOD OF COMMUNICATION FOR SUCH AN ASSEMBLY

Abstract

An arrangement comprises a tire casing, an electronic device for measuring a mounted assembly and an interface for bonding the casing and the electronic device, made of elastomeric material and covering the electronic device. The measuring electronic device comprises: a UHF radiofrequency antenna; and a circuit board with an electronic chip coupled to the UHF radiofrequency antenna and a sensor for measuring a parameter of the mounted assembly. The tire casing comprises: a crown, two sidewalls and two beads of revolution about a reference axis and first and second surfaces located internally and externally to the tire casing; and a median plane perpendicular to the reference axis. The interface is fastened in line with the crown to the second surface of the tire casing, and the feed point is located axially in the central region of the crown.

Claims

1.-22. (canceled)

23. An arrangement comprising: a tire casing; an electronic device for measuring parameters of a mounted assembly; and a bonding interface made of elastomeric material at least partially covering the electronic device and serving as an interface between the tire casing and the electronic device; the electronic device comprising: a UHF radiofrequency antenna defining a polar axis; and a circuit board comprising: an electronic chip electrically coupled to the UHF radiofrequency antenna by at least one galvanic transmission line; and at least one sensor for measuring a parameter of the mounted assembly; the tire casing comprising: a crown, two sidewalls and two beads of revolution about a reference axis defining a first surface located externally and a second surface located internally to the tire casing with respect to the reference axis; and a median plane perpendicular to the reference axis and equidistant from the two beads, wherein the bonding interface is fastened in line with the crown to the second surface of the tire casing, and wherein at least one feed point defined as an intersection between the polar axis and the at least one galvanic transmission line is located axially in a central region of the crown of the tire casing.

24. The arrangement according to claim 23, wherein the circuit board comprises a microcontroller, a capacitive element and a power manager, and the electronic components of the circuit board are low-consumption components.

25. The arrangement according to claim 23, wherein the electronic device comprises a ground plane connected to the circuit board.

26. The arrangement according to claim 23, wherein the at least one feed point is located in the median plane of the tire casing.

27. The arrangement according to claim 23, wherein the tire casing comprises at least one visual indicator located on the first surface of the tire casing in line with one of the sidewalls, and the bonding interface is located at an azimuth separated from an azimuth of the at least one visual indicator by less than 15 degrees.

28. The arrangement according to claim 27, wherein the azimuth of the bonding interface is superposed on the azimuth of the at least one visual indicator.

29. The arrangement according to claim 23, wherein the UHF radiofrequency antenna is a single-band half-wave dipole antenna, the total length L of which is comprised between the following limits:
0.9*C/(2*f)<L<1.1*C/(2*f), in which, C is a speed of radiofrequency waves in a medium in which the UHF radiofrequency antenna is embedded and f is a communication frequency of the UHF radiofrequency antenna.

30. The arrangement according to claim 23, wherein the polar axis of the UHF radiofrequency antenna is parallel to a circumferential direction of the tire casing.

31. The arrangement according to claim 23, wherein the polar axis of the UHF radiofrequency antenna is parallel to the reference axis of the tire casing.

32. A method for achieving communication between a mounted assembly and an external radiofrequency device comprising a radiofrequency antenna having a polar axis, the mounted assembly comprising an arrangement according to claim 23, comprising the following steps: positioning the external radiofrequency device radially at a radial distance R, with respect to the reference axis, comprised between one third and all of the height of the tire casing; bringing axially, in line with one of the sidewalls of the tire casing, the polar axis of the radiofrequency antenna of the external radiofrequency device to a distance D0, with respect to the first surface of the tire casing of the mounted assembly, defining a first read position; and transmitting a radiofrequency transmission with the external radiofrequency device for a duration T0 while angularly scanning a first angular sector β of α degrees.

33. The method according to claim 32, wherein, if no response has been obtained by the external radiofrequency device, the external radiofrequency device is moved to a second position located at α degrees from the first position before restarting the radiofrequency transmission.

34. The method according to claim 32, wherein, if no response has been obtained by the external radiofrequency device, the distance D0 between the polar axis of the antenna of the external radiofrequency device and the first surface of the tire casing is decreased by a factor γ before the radiofrequency transmission is restarted.

35. The method according to claim 32, wherein, if no response has been obtained by the external radiofrequency device, the angle α of the scanned first angular sector β is decreased by a factor μ before the radiofrequency transmission is restarted.

36. The method according to claim 32, wherein, if no response has been obtained by the external radiofrequency device, the duration T0 of the interrogation mode is multiplied by a factor ρ before the radiofrequency transmission is restarted.

37. The method according to claim 32, wherein the distance D0 is between 0 and 1 m.

38. The method according to claim 32, wherein the tire casing comprises at least one visual indicator located on the first surface of the tire casing in line with one of the sidewalls, and the bonding interface is located at an azimuth separated from an azimuth of the at least one visual indicator by less than 15 degrees, and wherein the external radiofrequency device is positioned in line with the at least one visual indicator.

39. The method according to claim 32, wherein the scanned angular sector β of the radiofrequency transmission is 30 degrees.

40. The method according to claim 32, wherein the duration T0 of the radiofrequency transmission is between 0.5 and 2.0 seconds.

41. The method according to claim 35, wherein the factor μ by which the scanning angle of the radiofrequency transmission is decreased is a real number.

42. The method according to claim 36, wherein the factor ρ by which the duration T0 of the radiofrequency transmission is multiplied is a real number.

43. The method according to claim 32, wherein the external radiofrequency device is in linear polarization mode.

44. The method according to claim 43, wherein the tire casing comprises at least one visual indicator located on the first surface of the tire casing in line with one of the sidewalls, and the bonding interface is located at an azimuth separated from an azimuth of the at least one visual indicator by less than 15 degrees, and wherein the polar axis of the antenna of the external radiofrequency device is oriented depending on information of the at least one visual indicator.

Description

[0095] The invention will be better understood upon reading the following description, which is given solely by way of example, and with reference to the appended figures, throughout which the same reference numerals designate identical parts, and in which:

[0096] FIG. 1 shows an overview of the electronic device according to the invention;

[0097] FIG. 2 is a cross-sectional view of the measuring system according to the invention;

[0098] FIG. 3 is a view from above of a strand of the dipole radiating antenna;

[0099] FIG. 4 is a view from above of a loop forming the strand of a dipole antenna according to the invention;

[0100] FIG. 5 is a cutaway in perspective of a tyre casing; and

[0101] FIG. 6 is an overview of the method for achieving communication with a mounted assembly comprising an arrangement according to the invention.

[0102] Below, the terms “tyre” and “pneumatic tyre” are employed equivalently and refer to any type of pneumatic or non-pneumatic tyre.

[0103] The term “electronic device” comprises the UHF radiofrequency antenna, the circuit board and the ground plane.

[0104] The term “measuring system” comprises the electronic device and the bonding interface.

[0105] FIG. 1 shows an overview of the electronic device 10 of the system for measuring a parameter of the mounted assembly. On the one hand, the radiocommunication portion comprises a UHF radiating antenna 20 that is connected to the circuit board 40 via the electronic chip 41. If needs be, an impedance-matching circuit 21 is interposed between its two components in order to couple them efficiently and to optimize the transfer of electric power.

[0106] The circuit board 40 comprises a first sub-assembly ensuring power management. This sub-assembly comprises, on the one hand, a power manager 42 that serves as an interface between the electronic chip 41 and the capacitive element 43. Specifically, the electrical energy delivered to the electronic chip 41 is directed to the power manager 42, which directs the flow of energy to the capacitive element 43. This capacitive element 43 is the energy store of the circuit board 40. When the capacitive element 43 has reached a certain threshold allowing the circuit board 40 to begin to operate, the energy of the capacitive element 43 is released to the circuit board 40 via the power manager 42.

[0107] The circuit board 40 also comprises a second sub-assembly that carries out the measurement and post-processes this measurement, firstly comprising, from the electronic chip 41, a microcontroller 44. This microcontroller 44 ensures the communication of information between the electronic chip 41 and the sensor 45 for measuring a parameter of the mounted assembly. At the very least, communication from the microcontroller 44 to the electronic chip 41 is carried out. Often, the communication is two-way. Specifically, either the electronic chip 41 sends an instruction from a list of instructions to the microcontroller 44, or the electronic chip 41 transmits the information received from the microcontroller 44, the latter verifying that the transmitted information is compliant. The microcontroller 44 is also in communication with the measuring sensor 45. Communication is at least from the measuring sensor 45 to the microcontroller 44. Often it is two-way, in order to acknowledge the information transmitted or to transmit an operation to the measuring sensor from among a list of possible operations to be carried out, such as, for example, carrying out a measurement or communicating the partial or complete content of the memory of the measuring sensor 45 or any other task to be performed by the measuring sensor 45.

[0108] Apart from these first two sub-assemblies connected to each other by means of an electric circuit, the circuit board 40 is connected to a ground plane 46. Of course, the electric circuit galvanically connects all of the elements of the circuit board 40. It will be noted that when the measuring sensor 45 is of analogue type, a digital/analogue converter is incorporated between the microcontroller 44 and the measuring sensor 45 in order to decode or encode the information between the digital mode specific to the electronic chip 41 and the analogue mode of the measuring sensor 45. Lastly, the power manager 42 transmits the energy necessary for the correct operation of the circuit board 40 to at least the microcontroller 44, which then redistributes it to the measuring sensor 45. However, the power manager 42 may, as indicated in the overview, also directly supply the measuring sensor 45 and, if necessary, the digital/analogue converter.

[0109] FIG. 2 is a cross section through the system 1 for measuring a parameter of the mounted assembly, in the OXZ-plane. The X-direction is the direction of the polar axis of the UHF radiating antenna 20, which is here a half-wave dipole. The Z-direction is the direction vertical to the circuit board 40. Lastly, the point O is the centre of the electronic chip 41. The latter is conventionally in the shape of a parallelepiped, the vertical Z-direction of which corresponds to its smallest dimension.

[0110] This measuring system 1 comprises a bonding interface 2 including the radiating antenna 20, the ground plane 46 and the circuit board 40. This bonding interface 2 is a mass made of an elastomer blend. Thus any elastomer/elastomer adhesion solution may be used to fasten the measuring system 1 to the tyre casing. The bonding interface 2 comprises a through-orifice 3 that places the fluid located outside the bonding interface 2 in communication with the pressure- and temperature-measuring sensor 45, the measurement of which focuses on the properties of this fluid.

[0111] In this configuration, the measuring system 1 also comprises a first helical metal strand 30 connected to the circuit board 40. This helical strand 30 is mechanically anchored by means of an orifice that passes vertically through the printed circuit board 50, and of soldering of this metallic strand 30 to a metal pad, such as for example a pad made of copper, included in the electric circuit 47 of the circuit board 40. This point of attachment of the strand 30 corresponds to the feed point of this strand 30. The first element of the circuit board 40 connected via the electric circuit 47 to this pad is the electronic chip 41. The latter is also connected via the electronic circuit 47 to a second strand 31 of the radiating antenna. This connection corresponds to a second feed point for the UHF radiofrequency antenna 30.

[0112] This second strand 31 is here a metal circular loop, it is therefore an areal structure the plane of which contains the axis of rotation of the first helical strand 30 and the main direction of the loop of which is parallel to the axis of rotation of the first strand 30. Thus the two strands 30 and 31 indeed form a dipole radiating antenna. The length of the path travelled along each strand is tailored to a central communication frequency of approximately 433 MHz when the measuring system 1 is incorporated into a tyre casing, on the crown thereof. The second strand of the radiating antenna may be, in another variant of the measuring device 10, a single helical metal strand connected to the circuit board 40 so that the longitudinal axes of each strand are coaxial.

[0113] The circuit board 40 is constructed from a printed circuit board 50, one of the metal, here copper, faces 51 of which has been chemically etched in order to form the electric circuit 47, which consists of conductive wires that connect connection pads to which the various elements of the electronic device 10 are connected. These pads may be unapertured or apertured depending on the system used to anchor the elements to the printed circuit board 50. In the case of the helical strand 30 and of the loop 31, the pads are apertured. In the case of the power manager or of the capacitive element or of the microcontroller 44, they are unapertured, these elements being fastened to the printed circuit board 50 by bonding. The other face 51′ of the printed circuit board 50 is covered by a bilayer laminate, the upper layer 52 of which is metal in order to form the ground plane 46. Here, the ground plane 46 is dissociated from the loop 31 forming the second strand of the radiating antenna even though the two elements were initially both joined to the upper layer 52 of the laminate. Chemical etching of the metal layer 52 of the bilayer laminate allowed them to be physically and electrically dissociated via the insulating lower layer of the laminate.

[0114] The connection between the ground plane 46 and the circuit board is made via connecting elements 60 that connect the upper surface 52 of the printed circuit board to its lower surface 51. Connection on the side of the lower surface 51 is achieved via the electric circuit 47.

[0115] The first face 51 of the printed circuit board 50 accommodates the various elements of the circuit board 40. These are mechanically fastened to the printed circuit board 50 and electrically connected to the electric circuit 47. Here only the sub-assembly that takes the measurement is shown in FIG. 2. Firstly, the microcontroller 44 is directly connected to the electronic chip 41. Next, a measuring sensor 45 of the pressure-sensor type is connected to the microcontroller 44, and located between these two components is an analogue/digital converter 48. A second measuring sensor 45′ of the digital-accelerometer type is galvanically connected directly to the microcontroller 44.

[0116] It will be noted that the pressure sensor 45 passes through the printed circuit board 50. Specifically, it is electrically connected to the electric printed circuit 47 on the first face 51 of the printed circuit board 50. However, the active part of the pressure sensor 45 is located above the upper layer 52 of the bilayer laminate in the Z-direction. The pressure sensor 45 is fastened in place after the other electronic components have been connected.

[0117] A protective layer 70 is then necessary to protect these elements from physico-chemical attacks from the external environment of the measuring system 1. This protection 70 is achieved based on parylene deposited by condensation on top of the assembly consisting of the complete circuit board 40, of the ground plane 46 and of the radiofrequency antenna 20. This deposition process ensures a constant small thickness of protector over the entire external surface. Thus, maximum protection is achieved with a minimum mass of protector. Beforehand, the active region of the pressure sensor 45 has been protected so as not to be covered by this protection 70. The parylene mainly ensures hermeticity to solid and liquid pollution. Lastly, this protector 70 is compatible with the elastomer blends from which the bonding interface 2 is made. Of course another protector such as epoxy resin might have been used, but employment thereof would not have been as advantageous as employment of parylene.

[0118] FIG. 3 is an example of strand 30 of a UHF radiating antenna in a configuration that is optimal with respect to energy efficiency. This configuration is a two-dimensional structure that integrates perfectly into the system for measuring a parameter of the mounted assembly. The two ends A and I of the strand define the X-axis representing the axis of the UHF radiating antenna or polar axis. The Y-axis is the direction perpendicular to the X-axis in the plane of the strand 30. The point A here corresponds to the feed point 22 of the strand 30 of a UHF radiofrequency antenna of the electronic device.

[0119] It comprises a metal wire firstly comprising a rectilinear segment 101 between points A and B, of a length representing 50% of the total length of the strand. The point A is the end of the strand 30 that will be galvanically connected to the electronic chip. The second portion of the strand 30, between the points B and H, is a right meander-type structure that terminates in a rectilinear segment between points H and I representing 0.5% of the total length of the strand 30. In fact, the segment between points B and H is a succession of meanders 102, 103, 104, 105, 106 and 107, the dimension of which in the X-direction is constant and of a value equivalent to 1.5% of the length of the strand 30. However, their dimension in the Y-direction continuously decreases. For example, the meander 103 is bounded by points C and D. For each meander, the path travelled along the meander may be broken down into a component in the X-direction and a component in the Y-direction. The X-component of each meander is by the construction of this strand constant and has a value equivalent to 3% of the length of the strand 30. However, the Y-component of each meander, from the end B to the end H, continuously decreases by a factor of 2 from meander to meander, the maximum dimension on the meander 102 being equivalent to 8% of the length of the strand 30. This X-component of the meander 104 is the sum of the elementary distances d1 and d3. Regarding the Y-component of the same meander 104, it is twice the elementary distance d2. The formulas of the X- and Y-components are similar from one meander to the next.

[0120] Therefore, the path L0 travelled along this strand 30 is thus the full distance of the strand 30. The value of L0 is about 80 millimetres, which is indeed comprised in the interval desired for a half-wave dipole radiating antenna operating at a frequency of 900 MHz.

[0121] The oriented path L1 of this strand corresponds to the distance travelled in the X-direction alone, the X-direction being the direction of the axis of the radiating antenna. This path L1 is then simply defined by the following formula:

[00001]$L.Math.1=a_1+\underset{i=b}{\overset{g}{.Math.}}.Math.\left(i_1+i_3\right)+h_1=0,685*L.Math..Math.0$

[0122] The value of L1 represents about 70 percent of the total path L0 travelled along the strand 30. Thus the role of most of the strand 30 is to permit the electric charge located on the strand 30 to be accelerated by the electric field of the radiofrequency device.

[0123] Lastly, the optimal oriented path L2 of this strand 30, which corresponds to the largest continuous portion of the strand 30 perfectly aligned with the X-direction, which corresponds to the axis of the radiating antenna, is then defined by the following formula:

L2=a.sub.1=0.5*L0

[0124] The optimal oriented path L2 is indeed more than 70 percent of the oriented path L1 of the strand 30 of the radiating antenna. In addition, this optimal oriented path L2 comprises the end A of the strand, which will be placed in line with the electrical connection to the electronic chip.

[0125] FIG. 4 is a view from above of a strand 32 of the UHF radiating antenna integrated into the ground plane 46 of the electronic device. The ground plane 46 is here bounded by a regular hexagon defining a total area of about 500 square millimetres. The ground plane 46 has on its face five connection elements 60 between the ground plane 46 and the circuit board, and allowing an electrical connection to be made. At one end of the hexagon is a small rectilinear segment 200, which will be neglected for the evaluation of the paths of the strand. Alignment of this rectilinear section 200 with the axis of the UHF radiofrequency antenna is desirable as it allows a half-wave dipole antenna to be produced in which a first strand is the loop 32 integrated into the ground plane 46. This alignment represents the X-axis or polar axis. The end left free of this rectilinear section 200 represents a feed point 22 of the UHF radiofrequency antenna. The Y-direction is orthonormal to the X- and Z-directions, where the Z-direction is the direction normal to the ground plane 46 directed externally to the circuit board.

[0126] Each vertex of the hexagon is defined by a letter from A to J in the clockwise direction around the hexagon in the XY-plane. Each segment q.sup.i of the hexagon has a length p which, depending on the orientation of the section of length p in the XY-plane, defines a component q.sup.i.sub.x in the X-direction and a component q.sup.i.sub.y in the Y-direction.

[0127] The loop strand 32 may then be considered to be located on the periphery of the ground plane 46. In fact, this region corresponds to the area of movement of the electric charge located on the ground plane 46 when the latter is placed in an electric field E parallel to the ground plane 46. The line of dots 300 represents what may be considered to be the thickness of this loop 32, so as to allow this thickness to be seen in FIG. 4.

[0128] The intersection of the loop 32 and the X-axis defines a first point O and a second point P, in order starting from the rectilinear section 200. The distance defined by the regular hexagon between these two points is constant, independently of the direction in which it is chosen to measure it around the regular hexagon. This distance travelled corresponds not only to the half-perimeter D of the loop 32 but also to the travelled path L0 of the loop 32. This distance is defined, considering solely segments q.sup.1 to q.sup.5 of the regular hexagon, by the following formula:

[00002]$L.Math.0=\underset{i=1}{\overset{5}{.Math.}}.Math.q^i=5.Math.p$

[0129] It is then easy to determine the oriented path L1 of the loop 32, simply by considering the projections of the sections of the regular hexagon onto the X-direction. Thus the oriented path L1 is obtained using the following formula:

[00003]$L.Math.1=\underset{i=1}{\overset{5}{.Math.}}.Math.q_x^i=3,72*p=0,74*L.Math..Math.0$

[0130] This loop-type strand 32 allows an oriented path suitable for achieving a sufficient energy efficiency to be obtained. However, this energy efficiency is not optimal due to the orientation of the loop strand 32. However, the particular shape of this antenna ensures the compactness of the measuring system, as it allows the ground plane 46 to play a first role as an electrical regulator of the circuit board and a second role as a radiofrequency strand.

[0131] FIG. 5 shows a cross section of a pneumatic tyre 501 according to the invention comprising a crown S extended by two sidewalls F and terminating in two beads B. In this case, the tyre 501 is intended to be mounted on a wheel (not shown in this figure) via the two beads B. A closed cavity containing at least one pressurized fluid is thus defined, this cavity being bounded both by the second surface 513 radially internal to the tyre 501 and by the external surface of the wheel. The tyre casing 501 also comprises a first surface 514 that is radially external to the tyre casing 501.

[0132] The reference axis 601, which corresponds to the reference axis or natural axis of rotation of the tyre 501, and the median plane 611, which is perpendicular to the reference axis 601 and equidistant from the two beads, will be noted. The intersection of the reference axis 601 with the median plane 611 defines the centre of the pneumatic tyre 600. A Cartesian coordinate system is defined at the centre of the pneumatic tyre 600, this system consisting of the reference axis 601, of a vertical axis 603 perpendicular to the ground and of a longitudinal axis 602 perpendicular to the other two axes. Furthermore, an axial plane 612 is defined that passes through the reference axis 601 and the longitudinal axis 602, parallel to the plane of the ground and perpendicular to the median plane 611. Lastly, the vertical plane 613 is the plane that is perpendicular both to the median plane 611 and to the axial plane 612 and that passes through the vertical axis 603.

[0133] Any material point of the tyre 501 is uniquely defined by its cylindrical coordinates (Y, R, θ). The scalar Y represents the axial distance to the centre of the pneumatic tyre 600 in the direction of the reference axis 601, i.e. the distance defined by the orthogonal projection of the material point of the tyre 501 onto the reference axis 601. A radial plane 614 making an angle θ to the vertical plane 613 around the reference axis 601 is defined. The material point of the tyre 501 is identified, in this radial plane 614, by the distance R to the centre of the pneumatic tyre 600 in the direction perpendicular to the reference axis 601, i.e. the distance identified by the orthogonal projection of this material point on the radial axis 604. The unit vector perpendicular to the radial plane 614, which vector forms, with the unit vectors of the axial direction 601 and radial direction 604, a direct system of axes, represents the circumferential direction of the tyre casing 501.

[0134] FIG. 6 is an overview of the method for achieving communication between a mounted assembly comprising an arrangement according to the first object of the invention and an external radiofrequency device. This method comprises three essential phases.

[0135] The first phase, incremented from 1000, consists in positioning the external radiofrequency device with respect to the tyre casing equipped with an electronic device for measuring parameters of the mounted assembly. This reader positioning comprises a first step 1001 consisting in positioning the external radiofrequency device radially with respect to the reference axis of the tyre casing. The external radiofrequency device is positioned between one third and all of the height of the sidewall of the tyre casing.

[0136] The second step 1002 consists in bringing axially the polar axis of the radiofrequency antenna of said external device to a distance D0 from the, radially external, second surface of the tyre casing. This distance D0 is preferably zero, leading to the best possible radiofrequency coupling. However, to avoid any contact between the two components, i.e. the tyre casing and the external radiofrequency device, it is possible to place the polar axis up to 1 metre away.

[0137] In the third positioning step 1003 of the communication method, the external radiofrequency device is placed angularly with respect to the tyre casing. If there is no visual indicator on the external sidewall of the mounted assembly indicating the presence of the measuring electronic device, the azimuth is chosen at random. Otherwise, the external radiofrequency device is positioned in such a way that the azimuth of the polar axis of the device is in line with the visual indicator of the tyre. Moreover, if the visual indicator provides the operator with information on an orientation of the polar axis of the measuring electronic device, the polar axis of the external device should then be oriented as indicated.

[0138] In the second phase of the communication method, which phase is incremented from 2000, the polarization mode of the radiofrequency antenna of the external device is chosen. Specifically, it is possible to choose a circular polarization mode or a linear polarization mode. The first mode leads to the transmission of radiofrequency energy in an omnidirectional manner, and the second mode leads to the transmission of energy in one single direction. For a given amount of energy transmitted by the external device, the second mode will transmit a higher power to the measuring electronic device. However, if the direction of the linear mode is orthogonal to the polar axis of the measuring electronic device, no energy will be transmitted to the electronic device. The polarization mode is chosen in step 2001.

[0139] If information on the orientation of the polar axis of the measuring electronic device is provided by the visual indicator on the sidewall of the tyre casing or on the data sheet of this same casing, the operator will choose the linear polarization mode in order to optimize the coupling of energy between the two components. Otherwise, and in any case prudently, he will choose the circular polarization mode to be certain to transmit energy to the measuring electronic device.

[0140] In the third phase of the communication method, which phase is incremented from 3000, the mode of radiofrequency interrogation between the external device and the measuring electronic device present in the tyre casing is chosen.

[0141] After the polarization mode of the antenna of the external radiofrequency device has been defined and the external radiofrequency device has been positioned with respect to the tyre casing, the first step 3001 consists in transmitting the UHF radiofrequency transmission to the electronic measuring device for a continuous duration T0. Thus, the external device transmits radiofrequency waves for a duration T0 in a chosen direction. This duration T0 is at least 500 milliseconds, in order to transfer sufficient energy to the electronic device for it to be able to perform its basic tasks. The duration T0 may be as long as two seconds in the event of poor coupling between the external device and the electronic device and of execution of a more complete set of tasks by the measuring device. However, for a standard pressure measurement, an interrogation duration of one second or two seconds is a good compromise.

[0142] After this first step, in step 3002, the operator angularly scans a sector β of α degrees from the first read position of the external radiofrequency device. The way in which this angular scan is performed is unimportant: it may be a reciprocating or progressive scan. The objective is to transmit a certain amount of radiofrequency energy to a given volume of the tyre casing.

[0143] Therefore, a scan over a sector of 30 degrees is reasonable, in particular in the case where no information is provided on the azimuthal position of the measuring electronic device. However, the coupling will be more efficient with an angle of 20 degrees, above all if the request made by the operator via the external device is a request, such as a request for the inflation pressure of the mounted assembly corrected for thermal variations, that will cause the measuring electronic device to consume much power. Lastly, a 5-degree scan is entirely realistic in the case of presence of a visual indicator, even in circular polarization mode.

[0144] The third step 3003 of this phase consists in collecting the radiofrequency waves returned by the measuring electronic device in response to the interrogation, before this phase ends in a final step 3004 of stopping the radiofrequency transmission. Specifically, the measuring electronic device is a passive system that uses the radiofrequency transmission of the external device to transmit the requested responses. Thus, part of the radiofrequency-transmission duration T0 is devoted to receiving the returned radiofrequency waves.

[0145] Depending on whether a response is received from the measuring electronic device by the external device, the communication method will either be stopped, in step 5001, since the requested information has been transmitted, or adjustments made to the communication method via a correction phase that is incremented from 4000.

[0146] There are two separate categories of correcting steps. The first category aims to optimize the positioning of the external radiofrequency device with respect to the measuring electronic device: the associated steps are incremented from 4100. The second category is more to do with the radiofrequency interrogation mode: the corresponding steps are incremented from 4300.

[0147] In the context of optimization of the position of the external device with respect to the measuring electronic device, the possible first step 4101 consists in decreasing the axial distance D0 between the external device and the tyre casing accommodating the electronic device. This step is in particular to be envisaged in the case of a request that is said to consume much power in the measuring electronic device, for example a request for the inflation pressure of the mounted assembly corrected for thermal variations.

[0148] The second step 4102 conceivable in this category consists in modifying the scanned angular sector. This correction is highly recommended in the absence of a visual indicator on the sidewall of the tyre providing the operator with information on the azimuthal position of the measuring electronic device within the tyre casing.

[0149] Among the steps of the second category of corrections, step 4301 consists in extending the duration T0 of radiofrequency transmission from the external device. This correction is desirable if the polarization mode of the radiofrequency antenna is of the circular polarization type, the transmission of radiofrequency energy to the measuring electronic device not being optimal in this mode. Likewise, if the requested request consumes much power, it is preferable to also increase the duration of the radiofrequency transmission.

[0150] Lastly, if there is no visual indicator on the external surface of the sidewall of the tyre casing and a first angular sector β has been scanned without obtaining a response in return, the operator may choose to implement step 4302, which consists in decreasing the angular amplitude of the scan in order to transmit, for a given duration T0 of the radiofrequency transmission, a greater amount of energy to the measuring electronic device.

[0151] When one or more correcting steps are carried out, it is recommendable to carry out the interrogating phase again in order to obtain a second communication-method result. In case of a response, the communication method ends in step 5001. Otherwise, new corrections that are reasonable with respect to the range of the various parameters of the communication method will need to be chosen and the interrogation mode restarted.