ELECTRONIC MEMBER TRANSMITTING AN ITEM OF IDENTIFICATION INFORMATION DURING A STATE CHANGE

Abstract

Electronic member comprising: A movement sensor and/or a proximity sensor; A microprocessor coupled to the sensor to form a data signal; A storage area connected to the microprocessor for storing a part of the data signal and an identification information element; An energy source; and A radio transmitter connected to the microprocessor;
characterized in that the microprocessor is capable of defining two states of the electronic member, the storage area contains a predetermined change of state which is defined on the basis of the two states, the microprocessor is capable, having detected the predetermined change of state, of transmitting the identification information element via a radiofrequency signal transmitted during a time interval T and then stopping the transmission of the radiofrequency signal at the end of said time interval T and the time interval T is between 20 seconds and 10 minutes.

Claims

1.-14. (canceled)

15. An electronic member (1) comprising: at least one movement sensor (4), a signal of which is sensitive to movement of the electronic member (1), and/or at least one proximity sensor (4), a signal of which is sensitive to a distance of the at least one proximity sensor from an object outside the electronic member (1); a microprocessor (2) coupled to the at least one movement sensor (4) and/or to the at least one proximity sensor (4) to create a data signal; a storage area (5, 5a, 5b) connected to the microprocessor (2) for storing at least one part of a data signal representative of the at least one sensor (4, 4) and at least one identification information element; an energy source (3); and a radio transmitter (6) connected to the microprocessor (2), wherein the microprocessor (2) is capable of defining at least two states of the electronic member on the basis of the at least one part of the data signal, wherein the storage area contains at least one predetermined change of state which is defined on a basis of the at least two states of the electronic member, wherein the microprocessor (2) is capable, when the microprocessor (2) has detected the at least one predetermined change of state of the electronic member, of transmitting the at least one identification information element via a radiofrequency signal transmitted during a time interval T and then stopping the transmission of the radiofrequency signal at the end of the time interval T, and wherein the time interval T of the transmission of the radiofrequency signal is between 20 seconds and 10 minutes.

16. The electronic member according to claim 15, wherein, an amplitude of the at least one part of the data signal constituting an information element for determining the state of the electronic member, each state of the electronic member being limited, in the at least one part of the data signal, by at least a first limit value, and the electronic member being in a given state, the crossing of the at least a first limit value by at least one value of the at least one part of the data signal characterizes the change of state of the electronic member.

17. The electronic member according to claim 16, wherein the at least a first limit value is a value defined on a basis of at least a critical distance or a critical velocity or a critical acceleration.

18. The electronic member according to claim 15, wherein, repetition of a pattern in the at least one part of the data signal constituting an information element for determining the state of the electronic member, and the electronic member being in a given state, the exceeding of a number N of patterns observed during a period T in the at least one part of the data signal characterizes a change of state of the electronic member.

19. The electronic member according to claim 18, wherein the period T is proportional to an inverse of a second critical velocity of the electronic member.

20. The electronic member according to claim 15, wherein the at least one movement sensor (4) is selected from the group consisting of inertial sensors and angular sensors.

21. The electronic member according to claim 15, wherein the at least one proximity sensor (4) is selected from the group consisting of optical sensors, electromagnetic sensors, inductive sensors, capacitive sensors, acoustic sensors, microwave sensors and push buttons.

22. The electronic member according to claim 15, wherein transmission of the radiofrequency signal during the time interval T takes place periodically over a period T which is between 0.5 second and 1 minute.

23. The electronic member according to claim 22, wherein the period T is defined according to the state of the electronic member.

24. The electronic member according to claim 15, wherein the radiofrequency signal has a transmission frequency of between 2400 and 2482 MHz.

25. A tire casing (100) comprising the electronic member according to claim 15 mounted integrally on the tire casing, wherein the at least one identification information element is selected from the group consisting of serial number of the tire casing, identity of the tire casing, serial number of the electronic member, and identity of the electronic member.

26. A conveyor belt comprising the electronic member according to claim 15 mounted integrally on the conveyor belt, wherein the at least one identification information element is selected from the group consisting of serial number of the conveyor belt, identity of the conveyor belt, serial number of the electronic member, and identity of the electronic member.

27. A track comprising the electronic member according to claim 15 mounted integrally on the track, wherein the at least one identification information element is selected from the group consisting of serial number of the track, identity of the track, serial number of the electronic member, and identity of the electronic member.

28. A mounted assembly comprising the electronic member according to claim 15 mounted integrally, a tire casing, and a wheel, wherein the at least one identification information element is selected from the group consisting of serial number of the tire casing, identity of the tire casing, serial number of the wheel, identity of the wheel, serial number of the electronic member and identity of the electronic member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The invention will be more readily understood from a reading of the following description, which mainly relates to an application of the mounted assembly type. These applications are provided solely by way of example and refer to the attached drawings, in which:

[0047] FIG. 1 is a simplified diagram of an electronic member according to one embodiment of the first object of the invention.

[0048] FIG. 2 is a mounted assembly comprising a tyre casing, fitted with an electronic member according to the second object of the invention, and a wheel.

[0049] FIG. 3a is a time signal emitted from a rotary encoder of an electronic member mounted on a tyre casing of a mounted assembly in a rolling condition according to the second object of the invention.

[0050] FIG. 3b is a time signal emitted from a accelerometer of an electronic member mounted on a wheel of a mounted assembly in a rolling condition according to the fifth object of the invention.

[0051] FIG. 3c is a time signal, representative of a proximity sensor, emitted from an accelerometer of an electronic member mounted on a mounted assembly in the proximity of an object, according to the fifth object of the invention.

[0052] FIG. 3d is a time signal emitted from an accelerometer of an electronic member mounted on a tyre casing of a mounted assembly in a rolling condition according to the second object of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0053] FIG. 1 shows a simplified diagram of an electronic member 1 according to the invention. This system comprises a microprocessor 2 coupled to an energy source 3 which may be a battery or an accumulator of energy which is, for example, supplied by a piezoelectric element. The microprocessor 2 is in communication with a movement sensor 4 sensitive to the movement of the electronic member, in this case the rotation speed about a predefined axis of rotation, which is the basis for the positioning and orientation of the movement sensor 4 with respect to the fixing support of the electronic member 1, not shown in this diagram. In this example, the microprocessor 2 controls the acquisition of the movement sensor 4 by transmitting the acquisition command to it, and retrieves the data obtained from the sensor 4. Similarly, the microprocessor 2 is linked to the mobility sensor 4 which in this case is an ultrasonic sensor sensitive to an ultrasound source emitting a calibrated noise. The emission of the source is represented here by a curved broken line. The link with this second sensor 4 is one-way in this case, because the sensor is passive. Additionally, the nearer the sensor 4, and therefore the electronic member 1, is to the ultrasound source, the stronger is the signal recorded by the sensor 4. By analysing this signal it is possible to deduce the distance between the electronic member 1 and the ultrasound source.

[0054] The microprocessor 2 is connected to a first storage area 5a for storing some of the data obtained from the sensor, for the purpose of performing some of the above operations for defining the rotation state of the electronic member 1. Preferably, this storage area 5a is of the flash memory or RAM memory type. The microprocessor 2 may also be linked to a second storage area 5b containing the identification information carried by the electronic member 1, together with the predetermined changes of state. Preferably, this storage area 5b is a read-only memory, that is to say an EPROM or EEPRO memory that is locked for writing but possibly rewritable. The two storage areas 5a and 5b form the storage area 5 of the electronic member 1. However, if the microprocessor 2 has enough cache memory, the whole storage area 5 of the electronic member may be located in the microprocessor 2 in order to optimize the response times.

[0055] Finally, the microprocessor 2 is in communication with a radio transmitter 6 receiving the energy required for transmission, the identification information to be transmitted and, if necessary, the periodicity of transmission to be provided by the microprocessor 2. The radio transmitter 6 encodes the information in a radiofrequency signal and sends it via one or more transmitting antennas. Preferably, the radio transmitter 6 operates in the UHF (Ultra High Frequency) band, and particularly in the 2.4 GHz band, which is the working band of BLE technology. Evidently, the radio transmitter 6 may have a bidirectional link with the microprocessor, for the purpose of modifying the parameters of the electronic member, such as the identification information and the predetermined changes of state, according to the physical support on which the electronic member is to be integrally mounted. Thus, remote programming may be carried out either during or after the installation of the electronic member on the physical support, thereby facilitating the industrial production of physical supports fitted with such electronic members.

[0056] FIG. 2 shows a section through a tyre casing 100 according to the second object of the invention. The tyre casing 100 comprises a crown S prolonged by two sidewalls F and terminating in two beads B. In this case, the tyre 100 is to be mounted on a private car or heavy goods vehicle wheel, which is not shown in this figure, at the position of the two beads B. Thus a closed cavity C, containing at least one pressurized fluid, is delimited, and is bounded by the inner surface 13 of the tyre casing 100 and the outer surface of the vehicle wheel. The outer surface of the tyre casing 100 is denoted 14.

[0057] The reference axis 201, corresponding to the natural axis of rotation of the tyre casing 100 or of the mounted assembly, should be noted, as should the mid-plane 211, perpendicular to the reference axis 201 and equidistant from the two beads B. The intersection of the reference axis 201 and the mid-plane 211 determines the centre of the tyre casing 200. A Cartesian reference frame in the centre of the tyre casing 200 is defined, consisting of the reference axis 201, a vertical axis 203 perpendicular to the ground, and a longitudinal axis 202 perpendicular to the other two axes. Furthermore, an axial plane 212 is defined that passes through the reference axis 201 and the longitudinal axis 202, parallel to the plane of the ground and perpendicular to the mid-plane 211. Lastly, the vertical plane 213 is the plane that is perpendicular both to the mid-plane 211 and to the axial plane 212 and that passes through the vertical axis 203.

[0058] Each material point of the tyre casing 100 is defined uniquely by its cylindrical coordinates (Y, R, ). The scalar Y represents the axial distance to the centre of the tyre casing 200 in the direction of the reference axis 201 defined by the orthogonal projection of the material point of the tyre casing 100 on the reference axis 201. A radial plane 214 making an angle to the vertical plane 213 around the reference axis 201 is defined. The material point of the tyre casing 100 is referenced in this radial plane 214 by the distance R to the centre of the pneumatic tyre in the direction perpendicular to the reference axis 201 identified by the orthogonal projection of this material point on the radial axis 204.

[0059] The tyre casing 100 comprises, at a right angle to its crown S on the inner surface 13 of the tyre casing, an electronic member corresponding to the first object of the invention. The electronic member is fixed on the inner surface 13 of the tyre casing 100 by means of a patch of elastomer compound which is well known to those skilled in the art. The electronic member here comprises a sensor sensitive to movement, in the form of a single-axis accelerometer whose main axis is positioned perpendicularly to the inner surface 13 of the tyre casing 100. Thus the signal delivered by the sensor is the acceleration in the radial direction with respect to the natural axis of rotation 201 of the mounted assembly.

[0060] Evidently, the electronic member may also be fitted with a three-axis accelerometer whose axes are not collinear with each other. At this moment, it is entirely possible, given the geometrical position of these three axes with respect to the inner surface 13 of the tyre casing, to define the radial acceleration experienced by the electronic member. Therefore, it is useful to know the positioning of the electronic member with respect to the physical support, in this case the tyre casing 100, in order to deliver a useful signal. However, in the context of the determination of the movement of the electronic member, it is preferable but not essential to determine the radial acceleration. An error of inclination has no effect on the capacity of the electronic member to determine its state of rotation, but it is then necessary to adapt the detection parameters such as the first or second limit value. Similarly, it is preferable to position the electronic member at a right angle to the crown assembly S of the tyre casing 100. However, there is no reason why it should not be positioned on the sidewall F or the bead B of the tyre casing 100.

[0061] FIG. 3 are time representations of various sensors sensitive to the movement of the electronic member or its proximity to objects when it is made integral with the physical supports which are components of the mounted assembly, for example at the position of the wheel or the tyre casing.

[0062] FIG. 3a is the time response of a rotary encoder of the electronic member mounted on a tyre casing during the rotation of the mounted assembly at constant velocity. The signal takes the form of a Dirac comb. Each Dirac represents a full rotation of the electronic member about the axis of rotation of the tyre casing. This data signal is bounded by the unit value. The critical periodicity for identifying a predetermined change of state of the tyre casing is represented here by the time interval T which starts in temporal terms at the level of the Dirac. For the signal analysis, a threshold value of 0.8 has been defined, the upward crossing of this threshold value being taken as the starting point of the timebase of the time interval T.

[0063] In order to constitute a change of state of the electronic member and therefore of the tyre casing, that is to say a change of rotation speed, the pattern of the wheel revolution signal must be repeated at least once in the period T. Here, the identification of the pattern requires the detection of the threshold value, which is a bijective value represented by the horizontal curve 1000 shown as a broken line. Additionally, given the direction in which the threshold value of 0.8 is crossed, it must be crossed twice in the period T to determine a change of state of the electronic member mounted integrally on the tyre casing. If there is no direction of crossing, the threshold value would have to be crossed three times. This is not the case here, because only a single upward crossing is observed. The electronic member, and therefore the tyre casing does not change its state, and therefore the electronic member does not trigger the radiofrequency transmission.

[0064] FIG. 3b corresponds to the time data signal of an electronic member mounted on a wheel of a mounted assembly. Said mounted assembly is in a condition of rolling at constant velocity. Here, the data signal is representative of the signal of an accelerometer in the radial direction of the mounted assembly with respect to the natural axis of rotation of the mounted assembly.

[0065] The determination of the change of state of the electronic member, and therefore the change of state of the object, in this case the mounted assembly, on which the electronic member is integrally mounted, may be carried out via the amplitude of the values of the data signal and also simply via the shape of the data signal, because of the effect of terrestrial gravity on the amplitude of the signal. In fact, during one rotation of the mounted assembly, the extreme vertical positions represent the minima and maxima of amplitude of the radial acceleration, enabling revolutions of wheels to be detected. Conversely, the vertical median positions of the accelerometer during the wheel revolution represent the central values of the signal between the minima and maxima. Evidently, if the radial acceleration of the mounted assembly is not constant, the signal is perturbed by a carrier linked to the instantaneous radial acceleration of the electronic member.

[0066] Taking into account the fact that the rotation speed is constant here, a time interval T corresponding to the switch to a particular state of rotation of the electronic member is determined. This time interval T starts from a reference point; here, the reference point is the threshold value 0.2 of the sinusoidal signal of the radial acceleration subtracted from the carrier linked to the rotation velocity of the mounted assembly. The threshold value is represented by the broken horizontal curve 1001. The upward crossing of the value 0.2 increments an encoder. If the encoder exceeds the number 2 during the period T, this signifies a change of state of the electronic member. Here, this event does indeed occur during the period T. At the end of the time interval T, the electronic member starts to transmit a radiofrequency signal at a time interval T. This radiofrequency signal comprises an identification information which in this case is the serial number of the tyre casing and the serial number of the wheel, which were previously put into the storage area of the electronic member during the formation of the mounted assembly.

[0067] FIG. 3c is the time response of the data signal of the electronic member representative of a microphone. The electronic member is initially positioned with respect to an object which is a source of white noise. The electronic member is mounted on a mounted assembly. The source of white noise is moved transversely with respect to the mounted assembly in a manner transverse to the latter, and a stop in this transverse movement is marked. Starting from a stop position, the noise source is brought towards the mounted assembly. The stop time is marked, and the noise source is then moved away from the electronic member along the same path, separating it from the mounted assembly. Here, the separation is greater than the initial distance between the noise source and the mounted assembly.

[0068] The aim here is to determine changes between two states of the electronic member corresponding to the distance from this electronic member to the noise source.

[0069] The first state correspond to a distance greater than a critical length LO, and the second state corresponds to a distance smaller than the same critical length. A calibration of the proximity sensor, represented by the microphone, to determine that the critical distance LO corresponds to a certain amplitude of the data signal representative of the microphone must be done. This amplitude is represented by the broken horizontal curve 1002 which forms a first limit value. Additionally, in this case, the simple detection of the first limit value is not sufficient to initiate the radiofrequency transmission. This transmission is subject to a delay effect. In fact, the signal must exceed the first limit value for a period T. This provides greater certainty that the critical length has been exceeded, by redundancy of information. Given that the change of state of the member between state 1 and state 2 has taken place and that this change is a predetermined change of state, the electronic member initiates the radiofrequency transmission for a time interval T.

[0070] The electronic member then detects the downward crossing of the first limit value, which in this case potentially corresponds to the switching of the electronic member from state 2 to state 1. In fact, this change of state must persist for a period T in order to validate this change of state of the electronic member. However, this change of state from state 2 to state 1 is not a predetermined change of state. Therefore, although the change of state persists, the electronic member does not transmit a radiofrequency signal. However, it is now in state 1. It waits for a return to state 2 and the necessary conditions for transmitting a radiofrequency signal carrying identification information about the mounted assembly during the same time interval T.

[0071] FIG. 3d is a time signal emitted from an accelerometer of an electronic member mounted on a tyre casing of a mounted assembly in a rolling condition. Here, the aim is to identify the state of the electronic member between a first state 1 and a second state 2 corresponding to a velocity of movement of the electronic member above a critical velocity. This critical velocity is represented in terms of acceleration along the radial direction by a first limit value which is proportional to the square of the critical velocity. This first limit value is represented by the broken horizontal curve 1003.

[0072] At the start of the temporal variation, the electronic member is in its state 1, the amplitude of the accelerometer signal being below the curve 1003. The acceleration then upwardly crosses the value defined by the curve 1003. This is confirmed after a delay Tj; that is to say, after this period the amplitude of the signal is still above the curve 1003, which signifies that the electronic member has changed its state and switched to state 2. Since this change of state is a predetermined change of state for the electronic member, the latter starts to transmit a radiofrequency signal comprising the identification information of the tyre casing after the delay Tj. This transmission takes place during the time interval T, via a signal transmitted periodically during this time interval T. The electronic member then stops its radiofrequency transmission. During this time, however, the amplitude of the data signal crosses the curve 1003 downwardly, before crossing it upwardly again. This dip in the data signal is specific to the tyre casing in the rolling condition. This is because, when the accelerometer of the electronic member is in the contact area, corresponding to the material point of the tyre casing in contact with the ground, the accelerometer observes an acceleration of virtually zero, due to this contact. This transient switch lasts for only a part of the wheel revolution of the tyre casing, not exceeding 10% of this wheel revolution. In temporal terms, this switch of the accelerometer to a virtually zero value continues for a short period which is a function of the velocity of the tyre casing. To avoid misleading the electronic member about its state, it is useful, for example, to define a second delay Ti which is a function of the critical velocity and the characteristics of the tyre casing, in order to prevent the electronic member from making an untimely and erroneous decision because it considers that the electronic member has returned to state 1. The electronic member re-analyses the amplitude of the data signal after this delay Ti. If this value is again above the curve 1003, this means that the electronic member is still in its initial state, that is to say its state 2. If it detects that the amplitude of the signal is still below the curve 1003, it deduces that the electronic member has switched to its state 1. Here, the switch from state 2 to state 1 is not a predetermined change of state of the electronic member, and the latter does not start to transmit a radiofrequency signal. However, it is now in state 1. The duration of state 1 of the electronic member attached to the tyre casing is indicated by the white rectangle, and the duration of state 2 is indicated by the black rectangle.