Method and ststem for operating a detection device

Abstract

Method and system (1) for operating a detection device (4) fixed on an inner surface (5) of a tyre (3) in a current time cycle having a duration not exceeding a rotation period of said tyre (3), said system (1) comprising said detection device (4) and a processing unit (8), operatively connected to said detection device (4), and programmed to: start, and subsequently stop, an acquisition of a signal (S) representative of a motion of a portion (30) of said tyre (3) in an acquisition time window (TA), transmit said signal (S) and / or at least one processed data obtained as a function of said signal (S) in a transmission time window (TT), and determine said acquisition time window (TA) as a function of at least one of a first parameter (w) representative of an angular velocity of said tyre (3) and a second parameter (T) representative of said rotation period, with said transmission time window (TT) temporally disjoint from said acquisition time window (TA).

Description

[0001] DESCRIPTION

[0002] Title: METHOD AND STSTEM FOR OPERATING A DETECTION DEVICE

[0003] Technical field of the invention

[0004] The present invention relates to a method, and a related system, for operating a detection device fixed on an inner surface of a tyre.

[0005] State of the art

[0006] It is known to fix at least one detection device on an inner surface of at least one tyre to be mounted on a vehicle, to acquire a signal representative of a motion of a portion of the tyre in rolling.

[0007] Typically, a tyre has a substantially toroidal structure around a rotation axis thereof during operation, and presents an equatorial plane orthogonal to the rotation axis, said equatorial plane being typically a plane of (substantial) geometric symmetry (e.g. neglecting possible minor asymmetries, such as a tread pattern and / or writings on sidewalls and / or an internal structure).

[0008] The expression "crown portion” means a portion of the tyre positioned in correspondence with a tread band.

[0009] The term "radial” is used with reference to a direction perpendicular to the rotation axis of the tyre.

[0010] The expression "footprint” means a portion of an external surface of the tread band that, during rolling of the mounted tyre subjected to a load (for example due to mounting under a vehicle), at each instant is in contact with a rolling surface. The footprint typically has substantially null curvature (or a substantially infinite radius of curvature), or in any case substantially assumes a conformation of the rolling surface. The expression "footprint area” means a corresponding crown portion instantaneously corresponding to the footprint.

[0011] The expression "passage in correspondence with the footprint”, referred to the portion of the tyre, means an interval, expressed for example in units of time or in degrees of rotation (e.g. with respect to a complete rotation), in which the portion of the tyre, due to rotation of the tyre, continuously lies within the footprint of the tyre.

[0012] Document US 8,424,375 B2 describes a method for operating a sensor, on or in a tyre of a vehicle, with a first sampling frequency in a first time interval and with a second sampling frequency in a second time interval.

[0013] Document EP 3 741 588 B1 describes a method and a system for acquiring data from a sensor mounted in a tyre. Document US 8,096, 172 B2 describes a method for wireless communication, wherein a transmission angle along a circumference of a revolution is determined, wherein a transmission time of the transmission angle is determined at least in part based on a time required to complete a revolution, and wherein a signal is transmitted wirelessly at the transmission angle and at the transmission time.

[0014] Summary of the invention

[0015] During rolling of a tyre of a vehicle caused by advancement of the vehicle, it is advantageous to acquire over time at least one signal representative of a motion of a portion of the tyre, for example an accelerometric signal, a straingauge signal, or a velocity signal. In fact, from the signal it is possible to obtain numerous information relating to motion conditions of the tyre, such as for example adhesion, sliding, presence of an aquaplaning condition, etc., useful for safety purposes.

[0016] In particular, the Applicant has observed that, with reference to a complete revolution of the tyre, it is advantageous to acquire the signal at least during a passage of the portion of the tyre (and therefore of the detection device) in correspondence with the footprint of the tyre. In fact, the signal contains a greatest amount of extractable information useful for the purposes indicated above.

[0017] Similarly, in order to be able to have the useful information extractable from the acquired signal, it is also advantageous to promptly transmit the signal externally from the detection device, for example to a reception unit, by which the signal can be made available to a processor for appropriate processing operations.

[0018] On the other hand, some limitations impose stringent constraints on actual possibilities of acquisition and transmission of the signal by the detection device. For example, an ideal intention to acquire the signal over extended portions of a wheel revolution, ideally over an entire wheel revolution, and to promptly transmit the signal as soon as the signal is acquired, is counterbalanced by the need to limit the consumption of electrical energy present in accumulators or converters, e.g. a battery and / or an energy harvesting element with which the detection device is typically provided, the accumulators or converters having limited capacity, and a charge or, more generally, energy consumption of the accumulators or converters having to be preserved as much as possible over time.

[0019] In particular, acquisition over extended portions of the wheel revolution and prompt transmission of data are typically energetically demanding.

[0020] Therefore, the Applicant, also in light of the solutions known as indicated above, has perceived a need to organize activities performed by the detection device in time available for a wheel revolution of the tyre (e.g. a rotation period), in an appropriate manner, in order to obtain desired advantages indicated above (e.g. acquisition of the signal at least in a region of interest and prompt transmission of data), while limiting, up to eliminating, corresponding issues related to technological constraints and energy consumption.

[0021] In this context, the Applicant has therefore addressed a problem of operating a detection device in an energetically efficient manner without at the same time having to lose relevant portions of a signal representative of a motion of a portion of the tyre, in order to collect useful information, and at the same time to be able to promptly have the acquired signal available.

[0022] According to the Applicant, the problem indicated above is solved by a method, and a related system, for operating a detection device, which provides to subdivide a time of a rotation period of the tyre into at least one acquisition time window of a signal representative of a motion of a portion of the tyre and into a subsequent transmission time window of the signal, the acquisition time window and the transmission time window being temporally disjoint from each other, and wherein the acquisition time window is determined as a function of at least one of a first parameter representative of an angular velocity of the tyre and a second parameter representative of a rotation period of the tyre.

[0023] According to one aspect, the invention relates to a method for operating a detection device fixed on an inner surface of a tyre in a current time cycle not exceeding a rotation period of said tyre.

[0024] Preferably, operating the detection device, in the current time cycle, comprises starting, and subsequently stopping, an acquisition of a signal representative of a motion of a portion of said tyre, the signal comprising at least one entire passage of said portion of the tyre in correspondence with a footprint of said tyre in an acquisition time window.

[0025] Preferably, operating the detection device, in the current time cycle, comprises transmitting, preferably to a reception unit distinct from said detection device, said signal and / or at least one processed data obtained as a function of said signal, in a transmission time window.

[0026] Preferably, it is provided to determine said acquisition time window as a function of at least one of a first parameter representative of an angular velocity of said tyre and a second parameter representative of a rotation period of said tyre.

[0027] Preferably, said transmission time window is temporally disjoint from said acquisition time window in said current time cycle.

[0028] According to another aspect, the invention relates to a system for operating a detection device fixed on an inner surface of a tyre.

[0029] Preferably, said system comprises said detection device.

[0030] Preferably, said system comprises a processing unit, operatively connected to said detection device, and programmed to operate, in a current time cycle not exceeding a rotation period of said tyre, said detection device. Preferably, said processing unit is programmed to, in said current time cycle, command said detection device for starting, and subsequently stopping, an acquisition of a signal representative of a motion of a portion of said tyre comprising at least one entire passage of said portion of said tyre in correspondence with a footprint of said tyre in an acquisition time window.

[0031] Preferably, said processing unit is programmed to, in said current time cycle, command said detection device for transmitting, more preferably to a reception unit distinct from said detection device, said signal and / or at least one processed data obtained as a function of said signal, in a transmission time window.

[0032] Preferably, said processing unit is further programmed to determine said acquisition time window as a function of at least one of a first parameter representative of an angular velocity of said tyre and a second parameter representative of a rotation period of said tyre, wherein preferably said transmission time window is temporally disjoint from said acquisition time window in said current time cycle.

[0033] According to the Applicant, comprising both the acquisition time window and the transmission time window entirely within the current time cycle having a duration less than or equal to the rotation period of the tyre, while at the same time keeping the acquisition time window and the transmission time window temporally disjoint from each other, namely not even partially temporally overlapping, wherein the acquisition time window is determined as a function of at least one of the first parameter and the second parameter, allows, potentially at each wheel revolution, to recalculate a temporal extension of the acquisition time window such that the acquired signal in any case comprises the passage of the detection device in correspondence with the footprint, while at the same time maintaining useful time for performing transmission of the signal.

[0034] This allows, on the one hand, not to renounce acquisition of signal information in a region of greatest interest, while at the same time maintaining the possibility of prompt transmission of the acquired information, thus obtaining prompt availability of information with a smallest possible granularity, since the information is made available as soon as the information is acquired, namely within a temporal arc belonging to the same wheel revolution in which the information is acquired, and, on the other hand, strongly limiting, thanks to temporal separation between the acquisition time window and the transmission time window, energy consumption. In fact, by temporally separating the acquisition phase and the transmission phase from each other, use of a complex processor (for example of the processing unit) which necessarily entails significant consumption, is avoided, use of simpler hardware therefore being sufficient and consequently less energetically demanding.

[0035] In other words, the Applicant has found that by subdividing a total time of a wheel revolution (namely of a complete rotation of the detection device) into the acquisition time window, temporally positioned such that the acquired signal comprises the passage of the detection device in correspondence with the footprint, and into the transmission time window, keeping the acquisition time window and the transmission time window disjoint and sequential, and by determining, potentially at each wheel revolution, the temporal extension of the acquisition time window as a function of the first parameter and / or of the second parameter, it is possible to organize with extreme precision and rationality operative times available in the wheel revolution, guaranteeing that the detection device is operated entirely within the rotation period of the tyre and obtaining desired information with extreme promptness and at the same time with energy saving.

[0036] The present invention, in one or more of the aspects indicated above, can present one or more of the following preferred characteristics.

[0037] Preferably, said processing unit is programmed to perform any embodiment of the method of the present invention. Preferably, operating said detection device is repeated cyclically over time, more preferably with a period substantially equal to a rotation period of said tyre. In this way, each rotation of said tyre corresponds to at least one acquisition of said signal and a respective transmission, to the advantage of prompt availability of information and updating of the information upon variation of rolling conditions.

[0038] Preferably, determining said acquisition time window comprises obtaining said at least one of said first parameter and said second parameter.

[0039] Preferably, determining said acquisition time window is performed, for each current time cycle, in a time cycle, more preferably immediately, preceding said current time cycle. In other words, said acquisition time window is determined, for each wheel revolution, during a wheel revolution immediately preceding, to the advantage of precision of information and synchronism of acquisition with rotation of said tyre, in particular with passage at the footprint of said detection device, as better described hereinafter.

[0040] Preferably, determining said acquisition time window is performed in a calculation time window belonging to said immediately preceding time cycle.

[0041] Preferably, said calculation time window is temporally disjoint from, and more preferably interposed between, an acquisition time window and a transmission time window of said immediately preceding time cycle. In this way, energy consumption is further limited and / or time of the wheel revolution is better subdivided.

[0042] Preferably, it is further provided to determine an acquisition time window of a time cycle directly subsequent to said current time cycle in a calculation time window belonging to said current time cycle.

[0043] Preferably, said calculation time window is temporally disjoint from, and more preferably interposed between, said acquisition time window and said transmission time window of said current time cycle.

[0044] In general, each time cycle preferably comprises a respective calculation time window, disjoint from respective acquisition time windows and transmission time windows, and more preferably temporally interposed between respective acquisition time windows and transmission time windows, wherein said acquisition time window for a time cycle immediately subsequent is determined. In this way, by separating all operative time windows from each other, energy consumption is further reduced.

[0045] Preferably, said transmission time window is temporally subsequent to said acquisition time window, for example for each current time cycle.

[0046] Preferably, said transmission time window is directly consecutive to said calculation time window, for example for each current time cycle.

[0047] According to the Applicant, one or more of, more preferably all of, the characteristics indicated above relating to temporal arrangement of at least two among the acquisition time window, the calculation time window, and the transmission time window allow, in combination with each other, to subdivide time of a wheel revolution in a highly precise and performing manner in order to perform all desired operations, without temporal overlap, to the advantage of greater precision and lower energy consumption. In particular, with the transmission time window directly consecutive to the calculation time window, transmission does not always occur at a fixed angular position and time of the detection device along the revolution, but as soon as the calculation phase is terminated (which in general can vary in duration from one time cycle to another), thus releasing constraints of a fixed-angle transmission, obtaining the advantages indicated above with a better allocation of temporal phases within the wheel revolution, with consequent advantages in terms of versatility of the application and energy saving (since the time windows are always temporally disjoint from each other).

[0048] Preferably, determining said acquisition time window comprises determining, based on a previous passage of said detection device at a footprint of said tyre, a reference angular position 90belonging to said footprint of said tyre. Preferably, determining said acquisition time window comprises determining an initial acquisition time instant of the signal as a function of at least one of said first parameter and said second parameter and of a predetermined initial angular acquisition position 91 included in a neighbourhood of 90+ 3 / 2TT.

[0049] Preferably, determining said acquisition time window comprises determining a final acquisition time instant of the signal as a function of at least one of said first parameter and said second parameter and of a predetermined final angular acquisition position included in a neighbourhood of 90+ 5 / 2TT.

[0050] Preferably, said acquisition time window is defined by said initial acquisition time instant and said final acquisition time instant.

[0051] According to the Applicant, by predetermining the initial and final angular acquisition positions in the respective neighbourhoods indicated above of the reference angular position plus respectively 3 / 2TT and 5 / 2TT, with the reference angular position belonging to the footprint of the tyre during the previous passage of the detection device in correspondence with the footprint, it is possible to determine the acquisition time window (e.g. for the subsequent time cycle) which angularly comprises, and thus with high certainty, at least one entire passage of the detection device in correspondence with the subsequent footprint. This also applies in an autonomously adaptive manner for each wheel revolution, as a function of the respective preceding wheel revolution, thanks to dependence of the initial and final acquisition time instants on the first parameter or the second parameter (which thus allows to take into account possible variations of rotation speed) and to belonging of the reference angular position to the footprint (which thus allows to center each time the acquisition time window provided for a wheel revolution on the footprint of the respectively preceding wheel revolution). In other words, in this way, for each current time cycle it is possible to synchronize acquisition of the signal with rotation of the tyre to acquire with greater certainty the portion of the signal of interest, namely comprising passage of the detection device at the footprint, based on rotation parameters of the preceding time cycle. In this way energy consumption is further limited and probability of acquisition of the region of interest is improved, also in an autonomously adaptive manner to possible variations of rotation of the tyre, strongly reducing risk of loss of the synchronism indicated above, since the identified acquisition time window is sufficiently wide to substantially necessarily comprise the entire passage of the detection device in correspondence with the footprint of the tyre (and thus allowing both to acquire the portion of the signal of interest and to determine the reference angular position), without excessively enlarging acquisition outside the region of interest.

[0052] Preferably, said method comprises starting said acquisition at said initial acquisition time instant. Preferably, said method comprises stopping said acquisition at said final acquisition time instant. In this way, the entire acquisition time window available is exploited.

[0053] Preferably, said neighbourhood of 90+ 3 / 2TT is a symmetrical neighbourhood centred at 90+ 3 / 2TT.

[0054] Preferably, said neighbourhood of 90+ 3 / 2TT has an extension less than or equal to TT radians, more preferably less than or equal to 2 / 3TT radians.

[0055] Preferably, said neighbourhood of 90+ 5 / 2TT is a symmetrical neighbourhood centred at 90+ 5 / 2TT.

[0056] Preferably, said neighbourhood of 90+ 5 / 2TT has an extension less than or equal to TT, more preferably less than or equal to 2 / 3TT.

[0057] According to the Applicant, one or more of the characteristics of symmetry and extension indicated above, referred to the neighbourhoods, contribute to improving probability of acquisition of the signal in correspondence with the footprint and / or reduce risk of loss of synchronisation of acquisition with rotation of the tyre, while at the same time limiting extension of the acquisition time window, in order to further reduce consumption.

[0058] Preferably, said initial acquisition angular position coincides with 90+ 3 / 2TT.

[0059] Preferably, said final acquisition angular position coincides with 90+ 5 / 2TT.

[0060] The Applicant has realised that such angular positions coinciding with the values indicated above are particularly suitable for identifying an angular portion of rotation within which to perform acquisition of the signal for the purpose of improving probability of acquiring, at each wheel revolution, the signal at least during passage of the detection device in correspondence with the footprint and / or for the purpose of reducing risk of loss of synchronisation between acquisition and rotation.

[0061] Preferably, said detection device is fixed to said inner surface in correspondence with a crown portion of said tyre. Preferably, said portion of said tyre coincides with said crown portion of the tyre. In other words, said signal is representative of a motion of said crown portion. In this way, the acquired signal is particularly useful for the purposes described above.

[0062] Preferably, said reference angular position coincides with an angular position of a centre, more preferably a geometrical centre, of a footprint area of said tyre. In this way, definition of the angular acquisition region, from which the acquisition time window derives, is particularly rational and advantageous for purposes of simple subdivision of the wheel revolution into the acquisition time window and the transmission time window, and optionally the calculation time window.

[0063] Preferably, said signal is an accelerometric signal representative of at least one component of an acceleration, more preferably a linear acceleration, experienced by said portion of said tyre.

[0064] In one embodiment, said signal is a velocity signal (or a displacement / deformation signal) representative of at least one component (axial, radial and / or tangential) of a linear velocity (or of a displacement / deformation) of said portion, namely of the crown portion, of said tyre.

[0065] Preferably, said detection device comprises at least one sensor suitable for detecting an accelerometric signal (or a velocity signal or a displacement / deformation signal) representative of at least one component, up to three components, of an acceleration (or of a velocity or of a displacement / deformation), more preferably linear, experienced by said crown portion of said tyre.

[0066] Preferably, said at least one component of the acceleration is selected from the group: axial component, radial component, and tangential component.

[0067] In one embodiment, said at least one component of the acceleration is the sole radial component. The Applicant has found that such component of the acceleration is particularly suitable for identifying passage of the detection device in correspondence with the footprint, to the advantage of precision and / or reliability of operation of the detection device in synchrony with rotation of the tyre. Moreover, such component of the acceleration has been found to be advantageous in terms of information content relating to rolling conditions of the tyre.

[0068] Preferably, determining said acquisition time window comprises determining a further parameter representative of an angular acceleration of said tyre as a function of said at least one of said first parameter and said second parameter, more preferably as a function of a variation over time of said at least one of said first parameter and said second parameter.

[0069] Preferably, determining said initial acquisition time instant and determining said final acquisition time instant are performed also as a function of said further parameter. In this way precision and / or reliability are increased.

[0070] Preferably, determining said initial acquisition time instant and determining said final acquisition time instant are performed as a function of an hourly law of a motion imparted to said detection device by a rolling motion of said tyre. For example, said hourly law identifies a uniformly accelerated circular motion. Use of said hourly law has proved to be particularly suitable for the present invention for purposes of greater precision and / or reliability of determination of time instants at which said detection device is expected to assume said predetermined angular position.

[0071] Preferably, said first parameter coincides with said angular velocity of said tyre.

[0072] Preferably, said second parameter coincides with said rotation period of said tyre.

[0073] Alternatively, the first parameter can comprise the rotation period of said tyre and the second parameter the angular velocity of said tyre.

[0074] Preferably, said further parameter representative of the angular acceleration coincides with said angular acceleration of said tyre.

[0075] In this way, determinations of the time instants are simple.

[0076] Preferably, obtaining said at least one of said first parameter and said second parameter is performed based on said previous passage of said detection device in correspondence with said footprint of said tyre.

[0077] Preferably, determining said acquisition time window comprises detecting said previous passage of said detection device at said footprint as a function of said signal representative of the motion of the portion of the tyre acquired in said acquisition time window of said time cycle directly preceding. In this way it is possible in turn to determine both the first parameter and the second parameter and the reference angular position, from which determination of the acquisition time window derives, as a function of the signal in a feedback manner with the last acquisition of the signal performed, to the advantage of greater precision and / or reliability and / or capability of synchronism of acquisition with rotation of said tyre.

[0078] More in detail, obtaining said at least one of said first parameter and said second parameter is preferably performed as a function of two directly preceding passages of said detection device in correspondence with said footprint which are temporally consecutive to each other.

[0079] For example, obtaining said at least one of said first parameter and said second parameter comprises detecting, for each previous passage, a respective transit of said detection device through a same angular position in correspondence with said footprint and detecting a time elapsed between said respective transits. In this way, the elapsed time is already representative of the period and therefore of the second parameter, while from a ratio between a rotation angle and said elapsed time the first parameter is obtained in a simple manner. Moreover, in this way, said at least one parameter is kept updated with rotation of said tyre.

[0080] Brief description of the figures

[0081] Figure 1 schematically shows a vehicle provided with a system for operating a detection device according to the present invention;

[0082] Figure 2 schematically shows a detail of Figure 1 ;

[0083] Figure 3 shows a partial section of Figure 2;

[0084] Figure 3b schematically shows a system for operating a detection device according to the present invention;

[0085] Figure 4 conceptually shows a subdivision of a wheel revolution into temporal phases according to the present invention;

[0086] Figure 5 shows a logical block diagram of a method according to the present invention; Figure 6 shows an example of a signal acquired in the method according to the present invention.

[0087] Detailed description of some embodiments of the invention

[0088] The characteristics and advantages of the present invention will be further clarified by the following detailed description of some embodiments, provided by way of example and not by way of limitation of the present invention, with reference to the accompanying figures.

[0089] Figure 1 schematically shows a vehicle 99 provided with a system 1 for operating a detection device 4 fixed on an inner surface 5 of a tyre 3 of the vehicle 99, according to the present invention. The vehicle 99 can be a vehicle with an internal combustion engine and / or an electric engine, with two or more driving wheels.

[0090] By way of example, the vehicle 99 comprises four wheels 7 (distributed on two axles), each wheel being provided with a respective tyre 3 (partially shown also in Figure 2) rolling on a surface (not shown). In one embodiment (not shown), the vehicle can have three or more axles.

[0091] The system 1 exemplarily comprises a detection device 4 for each tyre 3 (Figures 1 , 2 and 3). For example, the detection device 4 can be of the type described in one of the following documents in the name of the same Applicant: WO 2018 / 065846 A1 , WO 2019 / 123118 A1 , WO 2020 / 026281 A1 , WO 2020 / 026282 A1.

[0092] Exemplarily, each detection device 4 is fixed on the inner surface 5 of the respective tyre 3, in correspondence with a crown portion of the respective tyre 3 (Figures 2 and 3). In particular, the detection device 4 can be fixed to a liner of the tyre 3, typically by bonding (for example by means of a structural adhesive or by means of a pressuresensitive adhesive (PSA)). Preferably, the detection device 4 can be fixed substantially in correspondence with an equatorial plane 200 of the tyre 3. Further detection devices (not shown) can be arranged in a more lateral position on the inner surface of the tyre 3, and / or in different angular positions along the inner circumference of the tyre 3.

[0093] Exemplarily, the detection device 4 is structured to acquire, typically during rolling of the tyre 3, a signal S representative of a motion of a portion 30 of the tyre 3. In detail, given positioning of the detection device 4 on the inner surface 5, the portion 30 of the tyre coincides with the crown portion arranged in correspondence with the tread band and is substantially subtended by a base surface of the detection device (namely the surface by which the detection device is fixed to the inner surface 5, Figure 3).

[0094] Optionally, the portion 30 of the tyre can have an extension greater than the base surface of the detection device. Exemplarily, each detection device 4 comprises a respective sensor 41 (schematically shown in Figure 3b) suitable for detecting the signal S.

[0095] Exemplarily, the signal S is representative of the motion of the crown portion of the tyre and coincides with an accelerometric signal representative of at least the radial component of a linear acceleration of the crown portion. In one embodiment, the signal S is a velocity signal (or a displacement / deformation signal) representative of at least one component (axial, radial and / or tangential) of a linear velocity (or of a displacement / deformation) of the portion, namely of the crown portion, of the tyre.

[0096] Exemplarily, each detection device 4 further comprises an electronic unit 40 and an electric energy supply device 47, for example a button battery, for electric power supply of electrical and electronic components of the electronic unit and / or of the detection device 4. The electronic unit comprises for example a printed circuit board ("Printed Circuit Board” or "PCB”) on which electrical and electronic components of the electronic unit are mounted, including the sensor 41 and possible further sensors, and on which electrically conductive tracks for electrical interconnection among the various electrical and electronic components of the electronic unit are formed (for example by known abrasion or etching techniques).

[0097] Exemplarily, the electronic unit 40 can comprise, in addition to the sensor 41 , also one or more further sensors, for detecting one or more operative parameters of the tyre and / or further physical quantities. By way of example only, the operative parameters and / or the further physical quantities detectable can comprise: temperature, tyre deformations, pressure, velocity. Examples of sensors suitable for the purposes indicated above can be temperature sensors, pressure sensors, strain gauges, accelerometers, optical sensors, magneto-resistive sensors, inertial sensors, gyroscopes, etc.

[0098] With reference to Figure 3b, by way of example only, the electronic unit 40 can further comprise a processing and transmission system 43 operatively associated with at least the sensor 41 , and typically also with each further sensor, for processing and transmitting one or more data detected by the sensor; for example, the processing and transmission system 43 is configured for transmission to an instrumentation (not shown) available on board the vehicle 99 on which the tyre is mounted. The processing and transmission system can for example comprise a microprocessor or an integrated circuit (for example of the ASIC type - "Application Specific Integrated Circuit”) for performing processing and / or analysis of data coming from the sensor 41 , in order to make the data suitable for transmission from the detection device 4 to a receiver external to the tyre, and an antenna for transmitting the data and / or receiving further data, for example to and from the instrumentation on board the vehicle.

[0099] Exemplarily, moreover, the detection device 4 comprises a container configured to contain the electronic unit and the electric energy supply device. More in detail, the container comprises a base 45 and a housing body 42 having a plan extension included within a plan extension of the base. Typically, moreover, the container comprises at least one opening or through hole in communication with an internal volume of the detection device in which the electronic unit 40 is housed, to allow detection of pressure by at least one sensor of the electronic unit 40.

[0100] The system 1 exemplarily also comprises a processing unit 8 (shown only schematically in Figures 1 and 3b by means of a dashed box) operatively connected to the detection device 4, for example by radio signal and / or wired connection, and programmed to operate the detection device 4.

[0101] More in detail, exemplarily the processing unit 8 is connected to each detection device 4 with which the vehicle is provided, and programmed to operate each detection device.

[0102] In the example shown, the processing unit 8 exemplarily comprises a remote unit 81 installed on board the vehicle, and at least part (e.g. the microprocessor or integrated circuit) of the processing and transmission system 43 of each of the detection devices 4 (Figure 3b).

[0103] In general, the present invention contemplates any arrangement and / or logical and / or physical subdivision of the processing unit, which can for example be a single physical and / or logical unit or be composed of a plurality of distinct and cooperating physical and / or logical units (as in the case described and shown here), said units being able to be located, wholly or in part, in one or more of the following: detection device, in particular in one or more of the sensors and / or in the processing and transmission system 43, tyre (external to the detection device), rim, on board the vehicle, remote station in connection with the vehicle.

[0104] In use, the system 1 can perform a method for operating the detection device 4 in a current time cycle having a duration not exceeding a rotation period of the tyre 3, for example by means of one or more hardware devices programmed by means of one or more software modules resident and / or loaded on suitable memories.

[0105] One embodiment of the method according to the present invention will be described below with reference to Figures 4-6. The following will be described with reference to a given tyre 3 provided with the respective detection device 4, but can be conceptually extended to each of the tyres 3 of the vehicle 99.

[0106] Exemplarily, operating the detection device 4 is performed cyclically over time with a period substantially equal to the rotation period of the tyre, and for consecutive time cycles CY, wherein each time cycle CY is entirely contained, in temporal duration, within the rotation period, and preferably coincides with the rotation period. In other words, operating the detection device 4 is thus exemplarily performed for consecutive time cycles CY, wherein each time cycle CY exemplarily corresponds to a complete rotation, also referred to as a wheel revolution in the context of the present invention, of the tyre around the respective axis, and is completed within the rotation period of the tyre. In general, operating said detection device (4) exemplarily comprises, for each time cycle (CY), acquiring said signal (S) in an acquisition time window (TA) and transmitting said signal (S) (and / or at least one processed data obtained as a function of said signal (S)) in a transmission time window (TT), temporally subsequent to and disjoint from said acquisition time window (TA), wherein said acquisition time window (TA) is determined in a time cycle directly preceding said current time cycle (CY) so that said current time cycle (CY) is completed within a rotation period of said tyre.

[0107] First of all, therefore, said method exemplarily comprises, in a current time cycle (CY), starting, and subsequently stopping, acquisition of said signal (S) comprising at least one entire passage of said portion (30) of said tyre (3) in correspondence with a footprint (60) of said tyre (3) in said acquisition time window (TA).

[0108] Exemplarily, it is subsequently provided, still in said current time cycle (CY), to transmit, for example to a reception unit (not shown) distinct from said detection device (4), said signal (S) and / or at least one processed data obtained as a function of said signal (S), in said transmission time window (TT).

[0109] Exemplarily, it is further provided to determine said acquisition time window (TA) of said current time cycle (CY) as a function of at least one of a first parameter (w) representative of an angular velocity of said tyre (3) and a second parameter (T) representative of a rotation period of said tyre (3), with said transmission time window (TT) temporally disjoint from said acquisition time window (TA) in said current time cycle.

[0110] In detail, determining said acquisition time window (TA) of said current time cycle (CY) is performed in a time cycle (CYp) directly preceding said current time cycle (CY), more precisely in a calculation time window (TC) belonging to said preceding time cycle (CYp) (Figure 6).

[0111] In general, said time cycles (CY) are exemplarily all equal to each other, each time cycle exemplarily comprising a respective calculation time window (TC), disjoint from the respective acquisition time window (TA) and transmission time window (TT), and temporally interposed between the respective acquisition time window (TA) and transmission time window (TT), wherein said acquisition time window (TA) for the time cycle (CY) immediately subsequent is determined.

[0112] Exemplarily, more in detail, determining said acquisition time window (TA) comprises first obtaining, based on a previous passage of said detection device (4) in correspondence with said footprint (60) of said tyre (3), said at least one of said first parameter (w) and said second parameter (T).

[0113] Exemplarily, said first parameter (w) coincides with said angular velocity of said tyre and said second parameter (T) coincides with said rotation period.

[0114] Exemplarily, moreover, determining said acquisition time window (TA) further comprises determining, based on said previous passage of said detection device (4), also a reference angular position (0O) belonging to said footprint (60) of said tyre (3).

[0115] More in detail, determining said acquisition time window (TA) comprises detecting said previous passage of said detection device (4) in correspondence with said footprint (60) as a function of said signal (S) representative of a motion of said portion (30) of said tyre (3) acquired during the time cycle (CYp) directly preceding, exemplarily in said acquisition time window (TA) of said time cycle (CYp) directly preceding.

[0116] More in detail, obtaining said at least one of said first parameter (w) and said second parameter (T) is exemplarily performed as a function of two directly preceding passages of said detection device (4) in correspondence with said footprint (60) which are temporally consecutive to each other, each passage being detected as a function of said signal (S) acquired in a respective time cycle (CY). Exemplarily, determining said at least one parameter comprises detecting, for each previous passage, a respective transit of said detection device through a same angular position in correspondence with said footprint and detecting a time elapsed between said respective transits.

[0117] For example, each of said two passages of said detection device (4) indicated above can be detected, for said purposes, by recognising within the respective acquired signal (S) presence of at least one respective peak. In fact, particularly when said signal (S) is representative of a radial component of a linear acceleration of said crown portion, as in the present embodiment, said signal (S) comprises at least one peak (PK) within said acquisition time window, as for example shown in Figure 6. Said peak typically corresponds to passage of said detection device at said footprint and is due to the fact that, in said passage, the radial component of the acceleration undergoes a sharp displacement towards values around zero due to the fact that, in the footprint area, curvature of said tyre is substantially null, or, in other words, a radius of curvature of said portion tends to infinity, causing a substantial sudden cancellation of the radial acceleration detected by said detection device (from which said peak derives).

[0118] In this way, thanks for example to peak recognition algorithms, for example based on one or more thresholds, it is possible to determine presence of the peak, and thus recognise passage through the footprint area. Moreover, by taking as a reference a predetermined point of the signal (S) belonging to the peak, for example a maximum value or a median value, it is possible to detect a temporal coordinate of the peak. Assuming that occurrence of the peak marks passage of the detection device in correspondence with the footprint, it is therefore possible to obtain a time elapsed between two directly consecutive passages. From said time elapsed between the two passages it is for example possible to directly obtain the second parameter (T), or, from a ratio between a rotation angle (2TT) and said time elapsed, it is possible to obtain the first parameter (w). Moreover, at each subsequent new passage it is possible to update said at least one of the first parameter (w) and the second parameter (T) by comparing again the temporal coordinate of the new passage with the passage directly preceding in time.

[0119] Exemplarily, moreover, said reference angular position (0O) coincides with an angular position of a geometrical centre of the footprint area (60) of said tyre (3).

[0120] For example, from said signal (S) it is possible to determine a spatial extension of the footprint area and thus a respective geometrical centre.

[0121] Exemplarily, moreover, determining said acquisition time window (TA) of said current time cycle (CY) comprises determining an initial acquisition time instant (Ti) of said signal (S) as a function of said at least one of said first parameter (w) and said second parameter (T) and of a predetermined initial acquisition angular position (0i) included in a neighbourhood of (0O+ 3 / 2TT), and further comprises determining a final acquisition time instant (Tf) of said signal (S) as a function of said at least one of said first parameter (w) and said second parameter (T) and of a predetermined final acquisition angular position (0f) included in a neighbourhood of (0O+ 5 / 2TT).

[0122] For example, said neighbourhoods are preferably symmetrical neighbourhoods centred respectively at the values (0O+ 3 / 2TT) and (0O+ 5 / 2TT), having an extension less than or equal to TT radians, more preferably less than or equal to 2 / 3TT radians.

[0123] In a particularly preferred embodiment, said initial acquisition angular position coincides with (0O+ 3 / 2TT) and said final acquisition angular position coincides with (0O+ 5 / 2TT).

[0124] Exemplarily, therefore, said acquisition time window (TA) of said current time cycle (CY) is defined by said initial acquisition time instant (Ti) and said final acquisition time instant (Tf). More in detail, acquisition is exemplarily started at said initial acquisition time instant (Ti) and stopped at said final acquisition time instant (Tf), thus exploiting the entire acquisition time window.

[0125] Exemplarily, therefore, as for example shown in Figure 4, acquisition is performed only during, and for the entire, rotation of said detection device (4) from said initial acquisition angular position to said final acquisition angular position, namely during movement of said detection device (4) along a trajectory defined by a lower half, which indeed contains passage of said detection device through the footprint area (60), of an entire wheel revolution, said lower half also being centred, for each operating time cycle (CY), on the geometrical centre of the footprint portion detected in the time cycle directly preceding.

[0126] Exemplarily, determining said acquisition time window (TA) further comprises determining a further parameter (A) representative of an angular acceleration of said tyre (3) as a function of said at least one of said first parameter (w) and said second parameter (T), more in detail said further parameter (A) exemplarily coincides with said angular acceleration of said tyre (3), and determining said initial acquisition time instant (Ti) and said final acquisition time instant (Tf) also as a function of said further parameter (A). For example, said further parameter (A) can be determined as a function of a variation over time of said at least one of said first parameter (w) and said second parameter (T). Specifically, in a preferred embodiment, determining said initial acquisition time instant (Ti) and determining said final acquisition time instant (Tf) are performed as a function of an hourly law of a motion imparted to said detection device (4) by rolling of said tyre (3). For example, said hourly law can be of the following type (approximated to a second-order temporal term and exemplarily describing a uniformly accelerated rotational motion):

[0127] 1 o

[0128] 0(t) = 90+ wt + — At2where 90is said reference angular position, w is said first parameter, and A is said further parameter representative of angular acceleration.

[0129] For the time variable t, by imposing 90= 9, the following formula applies for the roots of said equation:

[0130] — w + lw2+ 40 i A t=- A - from which it is possible to obtain Ti and Tf by substituting the generic angle 9 with respectively said predetermined initial and final acquisition angular positions 9i and 9f (in the example described here equal respectively to 3 / 2TT and 5 / 2TT since 90= 9 is assumed).

[0131] Exemplarily, moreover, said transmission time window (TT) is directly consecutive to said calculation time window (TC) of the respective time cycle (CY).

[0132] Moreover, exemplarily, said calculation time window (TC) is directly consecutive to said acquisition time window (TA) of the respective time cycle (CY).

[0133] In other words, therefore, each time cycle (CY) of operation of said detection device (4) exemplarily comprises three distinct time windows sequentially arranged in time, as for example shown in Figure 4 or Figure 6.

[0134] Conceptually, therefore, each time cycle (CY) exemplarily starts with the respective acquisition time window (TA), namely starts at said initial acquisition time instant (Ti), followed exemplarily consecutively by the respective calculation time window (TC).

[0135] In the respective calculation time window (TC), the acquisition time window of the time cycle (CY) directly subsequent is exemplarily determined, as described above.

[0136] In said calculation time window, said signal (S) acquired in the acquisition time window (TA) just occurred can moreover be processed, for example in order to obtain said at least one processed data.

[0137] Immediately thereafter, the time cycle then exemplarily provides said transmission time window (TT), in which said signal (S) and / or said at least one processed data are transmitted.

[0138] Preferably, moreover (preferably independently of the exemplary embodiment described so far), it is generally provided not to allocate to any activity part of the time available of the time cycle (CY), preferably a time interval between an end of said transmission time window (TT) and said initial acquisition time instant (Ti) of the time cycle (CY) temporally subsequent (e.g. Figures 4 and 6). Said free time interval, or free time window (ID), can if necessary be allocated to said transmission time window (TT) of the respective time cycle. In fact, while said acquisition time window (TA) has a temporal duration variable as a function of rotation speed of said tyre, since said duration is defined by the instants at which said detection device is expected to pass through said initial and final acquisition angular positions, and therefore at higher rotation speeds the temporal duration of said acquisition time window (TA) is smaller, said transmission time window, by its very nature as time dedicated to data transmission, occurs at fixed time, namely has a fixed temporal duration independently of rotation speed of said tyre (which typically depends on an amount of data collected). Therefore, in case rotation speed is high, presence of said free time window (ID) is particularly advantageous in order to provide additional time to complete operation of said detection device within said time cycle (CY), namely necessarily before said initial acquisition time instant (Ti) of the subsequent time cycle.

[0139] The method according to the present invention therefore allows operating said detection device in such a manner as to allow a cyclic acquisition over time of said signal (S) only within said acquisition time window, but in any case in such a manner as to acquire, for each time cycle, the respective passage of said detection device in correspondence with said footprint, and thus of said region of interest, and to transmit said acquired signal, all within the rotation period of said tyre, by determining from time to time said acquisition time window (TA), and in an autonomously adaptive manner over time also upon variation of rolling variables of said tyre, such as for example angular velocity and / or angular acceleration.

[0140] In Figure 6 an example of said signal (S) acquired by means of the method described in the present embodiment is shown, wherein each acquisition comprises passage of said detection device (4) through said footprint area (60) of said tyre (3) characterized by a respective peak (in the exemplary case of said signal (S) being a radial acceleration signal). In detail, in Figure 6 acquisition of said signal (S) over time (t) in three consecutive time cycles (CY) is shown. It can be observed that for each time cycle acquisition is performed only between the respective initial and final acquisition time instants (Ti) and (Tf), followed by determination of said acquisition time window (TA) for the subsequent time cycle, performed in said calculation time window (TC), followed in turn by transmission in said transmission time window (TT).

[0141] As mentioned above, what has been described so far relates to operation of said detection device in a temporally cyclic manner with a period equal to the rotation period of said tyre.

[0142] In one embodiment, exemplarily before operating said detection device (4) in a temporally cyclic manner, said method can comprise a preliminary phase of acquisition of said signal (S) in a continuous manner for at least two or three consecutive wheel revolutions, namely for at least two or three complete rotations of said detection device. This allows preliminarily determining at least two consecutive passages of said detection device in correspondence with said footprint (preferably of said footprint area given positioning of said detection device (4) on said inner surface (5) of said tyre), from which it is possible to determine a first acquisition time window (TA), for example as described above, for example by obtaining said at least one of said first parameter (w) and said second parameter (T) from said two consecutive wheel revolutions.

[0143] Preferably, said continuous acquisition is maintained for at least one third complete wheel revolution in order to also determine a first value assumed by said further parameter (A) as a variation of said at least one of said first parameter and said second parameter in an evolution from the second to the third wheel revolution.

[0144] In such an embodiment, a last passage (which can be at the second wheel revolution or at the third wheel revolution) of said detection device (4) through said footprint (60) of said tyre (3) also allows determining a first value of said reference angular position (0O) in order to determine said first acquisition time window (TA).

[0145] At this point, once said first acquisition time window (TA) has been established, it is possible to acquire said signal (S), determine said acquisition time window (TA) of the subsequent time cycle, and transmit, in said current time cycle, said signal (S).

[0146] In one embodiment, for example as an alternative to the previous one, always before operating said detection device in a temporally cyclic manner, for example in order to determine first values of said parameters indicated above, it is possible to perform said preliminary phase of acquisition of said signal (S) in a continuous manner substantially for only one wheel revolution. In fact, said parameter representative of angular velocity can be obtained from measurement of radial acceleration, in particular in regions adjacent to said central peak. For example, said adjacent regions are representative of centripetal acceleration, from which angular velocity can be obtained. From said single wheel revolution it is moreover possible to obtain the corresponding passage of said detection device through said footprint in order to determine said reference angular position and then be able to start cyclic acquisition.

Claims

CLAIMS1. Method for operating a detection device (4) fixed on an inner surface (5) of a tyre (3), wherein operating said detection device (4) comprises, in a current time cycle (CY) not exceeding a rotation period of said tyre (3):- starting, and subsequently stopping, an acquisition of a signal (S) representative of a motion of a portion (30) of said tyre (3) comprising at least one entire passage of said portion (30) of the tyre (3) in correspondence with a footprint (60) of said tyre (3) in an acquisition time window (TA);- transmitting, to a reception unit distinct from said detection device (4), said signal (S) and / or at least one processed data obtained as a function of said signal (S), in a transmission time window (TT), wherein it is provided to determine said acquisition time window (TA) as a function of at least one of a first parameter (w) representative of an angular velocity of said tyre (3) and a second parameter (T) representative of a rotation period of said tyre (3) and wherein said transmission time window (TT) is temporally disjoint from said acquisition time window (TA) in said current time cycle (CY).

2. Method according to claim 1, wherein operating said detection device (4) is repeated cyclically over time with a period substantially equal to said rotation period of said tyre (3).

3. Method according to any one of the previous claims, wherein determining said acquisition time window (TA) is performed in a time cycle (CYp) immediately preceding said current time cycle (CY), wherein determining said acquisition time window (TA) is performed in a calculation time window (TC) belonging to said immediately preceding time cycle (CYp), and wherein said calculation time window (TC) is temporally disjoint from, and interposed between, an acquisition time window (TA) and a transmission time window (TT) of said immediately preceding time cycle (CYp).

4. Method according to any one of the previous claims, comprising determining an acquisition time window (TA) of a time cycle directly subsequent to said current time cycle (CY) in a calculation time window (TC) belonging to said current time cycle (CY), said calculation time window (TC) being temporally disjoint from, and interposed between, said acquisition time window (TA) and said transmission time window (TT) of said current time cycle (CY).

5. Method according to claim 4, wherein said transmission time window (TT) is temporally subsequent to said acquisition time window (TA) and wherein said transmission time window (TT) is directly consecutive to said calculation time window (TC).

6. Method according to any one of the previous claims, wherein determining said acquisition time window (TA) comprising:- determining, based on a previous passage of said detection device (4) at a footprint (60) of said tyre (3), a reference angular position 90belonging to said footprint (60) of said tyre (3);- determining an initial acquisition time instant (Ti) of the signal (S) as a function of at least one of said first (w) and second parameter (T) and of a predetermined initial angular acquisition position 0i included in a neighbourhood of 0O+ 3 / 2TT;- determining a final acquisition time instant (Tf) of the signal (S) as a function of at least one of said first (w) and second parameter (T) and of a predetermined final angular acquisition position 0f included in a neighbourhood of0O+ 5 / 2TT;7. Method according to claims 3 and 6, wherein determining said acquisition time window (TA) comprises detecting said previous passage of said detection device (4) at said footprint (60) as a function of said signal (S) representative of the motion of the portion (30) of tyre (3) acquired in said acquisition time window (TA) of said immediately preceding time cycle (CYp).

8. Method according to claim 6 or 7, wherein determining said acquisition time window (TA) comprises obtaining at least one of said first (w) and second parameter (T) based on said previous passage of said detection device (4) at said footprint (60) of said tyre (3).

9. Method according to any of claims 6 to 8, comprising starting said acquisition at said initial acquisition time instant (Ti) and stopping said acquisition at said final acquisition time instant (Tf).

10. Method according to any one of claims from 6 to 9, wherein said initial acquisition angular position 0i coincides with 0O+ 3 / 2TT, said final acquisition angular position 0f coincides with 0O+ 5 / 2TT, and wherein said reference angular position 0_|O coincides with an angular position of a center of a footprint area of said tyre (3).

11. Method according to any one of claims from 6 to 10, wherein determining said acquisition time window (TA) comprises obtaining a further parameter (A) representative of an angular acceleration of said tyre (3) as a function of said at least one of said first (w) and second parameter (T), and wherein determining said initial acquisition time instant (Ti) and determining said final acquisition time instant (Tf) are also performed as a function of said further parameter (A).

12. Method according to any one of claims from 6 to 11 , wherein determining said initial acquisition time instant (Ti) and determining said final acquisition time instant (Tf) are performed as a function of an hourly law of a motion imparted to said detection device (4) by a rolling motion of said tyre (3).

13. Method according to any one of the previous claims, wherein said signal (S) is an accelerometric signal representative of at least one component of an acceleration experienced by said portion (30) of said tyre (3), and wherein said at least one component of the acceleration is selected from the group: axial component, radial component, and tangential component.

14. System for operating a detection device (4) fixed on an inner surface (5) of a tyre (3), the system comprising said detection device (4) and a processing unit (8), operatively connected to said detection device (4), and programmed to operate in a current time cycle (CY) not exceeding a rotation period of said tyre (3), said detection device (4) performing the following steps:- commanding said detection device (4) for starting, and subsequently stopping, an acquisition of a signal (S) representative of a motion of a portion (30) of said tyre (3) comprising at least one entire passage of said portion (30) of said tyre (3) in correspondence with a footprint (60) of said tyre (3) in an acquisition time window (TA);- commanding said detection device (4) for transmitting, to a reception unit distinct from said detection device (4), said signal (S) and / or at least one processed data obtained as a function of said signal (S), in a transmission time window (TT), and wherein said processing unit (8) is further programmed to determine said acquisition time window (TA) as afunction of at least one of a first parameter (w) representative of an angular velocity of said tyre (3) and a second parameter (T) representative of a rotation period of said tyre (3), with said transmission time window (TT) temporally disjoint from said acquisition time window (TA) in said current time cycle (CY).

15. System (1) according to claim 14, wherein said detection device (4) is fixed to said inner surface (5) in correspondence of a crown portion of said tyre (3), and wherein said processing unit (8) is programmed to perform said method for operating said detection device (4) according to one or more of claims 2 to 13.

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