BRPI0318578B1 - METHODS FOR DETERMINING THE ASPECTS OF A ROLLING SURFACE ON WHICH TIRE IS ROLLING AND TO CONTROL THE BEHAVIOR OF A VEHICLE WHICH LEAST ONE MOUNTED, SYSTEM TO DETERMINE THE ASPERCE OF A ROLLING SURFACE ON WHICH THE TIRE IS ROLLING VEHICLE, AND, WHEEL - Google Patents

Description

“METHODS FOR DETERMINING THE HARNESS OF A TIRE SURFACE WHERE A TIRE IS ROLLING AND TO CONTROL THE BEHAVIOR OF A VEHICLE AT LEAST, A SYSTEM FOR DETERMINING THE HARNESS OF A SURFACE WHERE A TIRE IS ROLLING , TIRE FOR A VEHICLE, AND WHEEL ”The present invention relates to measuring devices associated with a tire mounted on a vehicle. The use of gauges placed inside a tire to detect specific quantities that characterize the operating conditions of the tire itself is known. US-A-2003/0058118 describes, inter alia, a detection device for the road surface contact area of a tire under load. Such a sensing device incorporates a radial accelerometer having the sensing axis aligned with the radius of the wheel on which the tire is mounted. This radial accelerometer provides a signal from which contact area information is received by elaboration. In this patent application it is specified that these elaborations also include a low frequency filtering operation to remove the "road noise" associated with the presence of holes, stones and gravel. US Patent Application 2003/0095050 describes a device for the continuous measurement of tire deformation, arising from which information concerning the vertical compression of the tire and the type of maneuver (advance in a straight or curved line) performed by the vehicle is obtained. . The sensor device described in this patent application includes a light emitter mounted on the tire support rim and a reflective surface attached to an inner wall of the tire. The Applicant has dealt with the problem that the measuring device to be associated with tires described in the known art provides a limited typology of information. In particular, the Applicant noted that conventional tire measurement systems and methods do not allow the collection of information regarding the surface on which the tire is rolling. The Applicant has observed that the limitations presented by conventional measuring devices can be overcome by extracting, from the signal provided by a measuring device associated with a tire, an output indicative of the roughness of the surface on which the vehicle advances and on which the tire rolls. Information associated with the roughness of the rolling surface on which the tire is rolling, such as the road surface, may find application very useful in monitoring and / or control systems with which the vehicle itself may be fitted. For example, such information may play an important role in the verification stages performed by an ABS (Anti-Lock System) system.

According to a first aspect, the present invention relates to a method for determining the roughness of the rolling surface on which a tire is rolling as defined by claim 1. Preferred embodiments of such a method are defined in dependent claims 2. 16 According to a second aspect, the invention relates to a method for verifying the behavior of a vehicle as described in claim 17 and, in its preferred embodiment, claim 18.

According to a third aspect, the invention relates to a system for determining the roughness of a rolling surface on which the tire is rolling as defined by claim 19 and to its preferred embodiment described in dependent claims 20-43.

According to a fourth aspect, the present invention relates to a tire as defined in claim 44. Preferred embodiments of the tire are described in dependent claims 45-50. A wheel as defined in claim 51 also forms a subject of the invention. In order to better understand the invention and appreciate the advantages, some of its non-limiting exemplary embodiments are described in the following, referring to the enclosed drawings, in which: Figure 1 shows a cross section of a tire to which a sensing device according to with a particular exemplary embodiment of the invention is fixed; Figure 2 shows schematically, and through functional blocks, an example of a sensing device according to the invention; Figure 3 shows schematically and through functional blocks an example of a fixed unit according to the invention and installable on board a vehicle; Figure 4 qualitatively shows the behavior of an acceleration signal obtainable from said sensor device; Figure 5 qualitatively shows the behavior of a low pass filtered acceleration signal Slp and a band pass filtered acceleration signal Sbp obtainable from filtering stages of said sensor device; Figure 6 shows three curves, obtained under a first experimental condition, expressing the tendency of a roughness parameter as a function of the angular velocity of the tire and characterizing three different rolling surfaces on which the tire is rolling; Figure 7 shows three other curves analogous to those of Figure 6, but deduced under a second experimental condition; Figure 8 shows, for three different tire models, three curves analogous to those of Figure 6 and related to the three distinct rolling surfaces on which the tire is rolling.

Referring to Figures 1, 2 and 3, an example of a measuring system operably associable with a vehicle tire (not shown) 11 according to the invention is described in the following. Such a system allows obtaining information related to the roughness level of a surface on which the vehicle advances. Advantageously, the system of the invention is able to provide this information in "running time", that is, it can operate during vehicle advancement, making the roughness-related information of essentially the same surface on which the vehicle is advancing available. It is noted that, as will be apparent from the following description, the system of the invention (which may include the same tire to which it is associated) may also have components or component blocks not attached to the tire, but arranged on board the vehicle or attached to a wheel to which the tire is mounted. In any case, such a system is to be considered operably associable with the tire provided that it is provided with at least one component which in its operation interacts with the tire or its parts, particularly during rolling of the tire itself.

According to the example described, the system of the invention includes a sensor device 3 operatively associated with the tire 11 and optionally a fixed unit 2 arranged on board the vehicle.

According to a particular embodiment of the invention, the sensor device 3 is attachable to the tire 11 and, in particular, is mountable within the cavity identified by the tire itself. Referring to this embodiment, Figure 1 shows a cross section of the wheel of a vehicle including tire 11 and a support rim 12. Such a tire 11 is of the type known by the term "tubeless", that is, without an inner chamber. Tire 11 is inflatable by means of an inflation valve 13 positioned, for example, in said support ring channel 12. Tire 11 includes a housing 16, terminating in two lugs 14 and 14 ', each formed along of an inner circumferential edge of the housing 16 to secure the tire 11 to the corresponding support rim 12. Beads 14 and 14 'include respective annular reinforcement cores 15 and 15', known as bead cores. The carcass 16 is formed of at least one reinforcing tarpaulin, including textile or metal strands, extending axially from one bead 14 to another 14 'in a toroidal profile, and having its ends associated with a respective bead core 15 and 15. '.

In conventional tires of the type known as "radial" the above mentioned strings are in a plane containing the tire's axis of rotation. An annular structure 17, known as the strap, is placed in a radially external position with respect to the shell 16. Typically, the strap structure 17 includes one or more strips of elastomeric material incorporating overlapping metal and / or textile cords . An elastomeric tread 18 is wrapped around the strap structure 17 and has a plurality of relief or block patterns (not shown) distributed according to a particular configuration for contact with a scroll surface. , such as the road surface. Two sides 19 and 19 ', in elastomeric material, are also placed in the housing in radially opposite lateral positions, each extending radially outwardly from the outer edges of the corresponding beads 14 and 14'.

In tubeless tires, the inner surface of the carcass 16 is normally covered with a protective cover 111, known as a liner, composed of one or more protective layers of air impermeable elastomeric material. The tire 11 may be provided with other conventional elements or components according to their specific typology such as, for example, bead fillers.

As shown in Figure 1, the following basic directions are definable for tire 11: radial direction Z, longitudinal (or forward) direction X and transverse direction Y.

According to the example of Figure 1, the sensor device 3, the structure of which will be described exemplarily later, is placed on an inner wall of the tire 11 opposite the tread 18. More particularly, it is found essentially in the line of the center of the tire 11 aligned with the radial axis Z. The sensing device 3 is fixed to at least one observation point P of the inner liner 111 by a fastener 332 which both adheres to a wall of a housing in the sensing device 3. and also to the lining itself. It is observed that according to the present invention the term "dot" is meant a region or part of tire 11 without zero dimensions, but small with respect to those of the whole tire, the effective value of which depends on the resolution of the sensor device 3. The fastener 332 is made of flexible rubbers such as natural or synthetic rubber (e.g. rubber made from conjugated dienes having from 4 to 10 carbon atoms such as polyisoprene rubber, polybutadiene, styrene butadiene and the like). The fastener 332 also advantageously has a protective effect on the sensor device 3, thereby reducing the likelihood of damage.

According to alternative embodiments, the sensor device 3 may be incorporated within the tire frame 11 in the tread region 18 and, for example, within the tread itself, or between the strap 17 and the tread 18. It is observed that sensing devices fixed not to a tire wall 11 but, for example, to the support rim 12 and / or sensing devices not placed on the center line of the tire but fixed or incorporated into the sidewalls 19 and 19 'of tire 11, or other regions thereof, may also be used.

Furthermore, according to the present invention, a plurality of sensor devices 3 associated with the tire 11 itself may be used. In particular, sensing devices placed at circumferentially spaced positions from one another, essentially at a fixed angle, may be used. For example, three sensor devices, analogous to device 3, placed circumferentially within tire 11, and spaced apart by an angle of approximately 120 °, may be used.

Referring to Figure 2, according to a particular exemplary embodiment, the sensor device 3 includes a measuring device (MD) 32, such as for providing a corresponding output terminal 50 with an electrical signal representative of movement in at least one said direction at least one point P of the tire itself during its rolling on the road surface. Advantageously, the measuring device 32 is such as to provide the output 50 with an electrical signal also representative of the movement components of the observation point P due to the deformations suffered by the tire 11 during rolling. It is observed that the deformations of the tire 11 detectable by the measuring device 32 are also those induced by the roughness of the surface on which the tire rolls, i.e. those roughness due to the particular texture of the road surface.

According to the preferred embodiment of the invention, the measuring device 32 is an accelerometer such as to provide at least one signal representative of the acceleration experienced by said tire point P along one or more of the following directions (defined according to commonly used terminology): radial or centripetal direction Z, longitudinal (or forward or tangential) direction X, lateral direction Y.

Measuring devices suitable for use in the present invention are commercially available and are made, for example, using MEMS (Micro-Electro-Mechanical Systems) technology, or are for example optical or acoustic sensors.

In this regard, the above-cited Patent Application US-A-2003/0095050 describes an optical type sensor used for tire footprint measurement which can be used in the present invention to generate a representative signal of movement components of observation point P due to deformation of tire 11 during rolling. This type of optical sensor is attachable to the rim 12 and is capable of detecting the movements of the fixed observation point P of the tire 11, lying on any inner wall thereof, to which a suitable reflective surface of the optical radiation emitted by the optical sensor can be applied.

According to an exemplary embodiment of the invention, the sensor device 3 further includes a signal processing stage 51 provided by the measuring device 32 to provide an output that is indicative of the roughness of the rolling surface on which the tire 11 is rolling. It is noted that processing stage 51 may include circuit blocks for analog signal processing and / or circuit blocks for digital signal processing. In addition, the above processing of the output signal of the measuring device 32 may be performed in whole or in part by software, that is, in the execution of an electronic data processor (computer) program.

With reference to the particular embodiment shown in Figure 2, processing stage 51 includes a filter block 52 having an input terminal connected to the output 50 of the metering device 32 and an output terminal connected to the input terminal of an analog converter. 53. Filter block 52 is for performing bandpass filtering and was outlined in Figure 2 as the serial connection of a first low pass filter (LPF) 56 and a high pass filter ( HPF) 57. These filters 56 and 57 may be composed, for example, of conventional analog filters. The passband B of the filter block 52 is selected in such a way as to extract from the acceleration signal present at the output terminal 50, a part containing frequency components, the source of which is referable to the roughness-induced stresses of the road surface. In addition, such passing band B is selected in such a way as to reduce or substantially eliminate those low frequency components relating to phenomena of no interest, such as, for example, load-correlated phenomena. vertical, skidding or drifting. The preselected through band B is identified by the lower cutoff frequency fi and the upper cutoff frequency fu of the filter block 52. Advantageously, the passband B is included between 300 Hz and 5,000 Hz and preferably between 300 Hz and 2,500 Hz, or more preferably between 500 Hz-1,200 Hz.

The passband B values given above were determined experimentally by the Applicant and emerged as being suitable for extracting the frequencies of interest from an acceleration signal. With reference to what the Applicant has noted that the vibrations of the tire structure 11 during its rolling on the road surface have an amplitude that is directly related to the roughness amplitude of the road surface itself and furthermore that the frequency band to be extracted , using the filter block 52, is dependent on the exact vibration modes of the tire structure 11 for stresses having a frequency corresponding to the particular exciting wavelengths of the specific road surface. It is noted that the frequency ranges indicated above have emerged to be in good agreement with those qualitative theoretical considerations regarding tire stresses due to the surface on which it rolls.

According to a particular embodiment of the invention, the high pass filter 57 and the first low pass filter 56 may have respective cutoff frequencies of less than fi and greater than fu constants (and in particular, constants varying with each other). tire angular velocity 11) and such that the corresponding through band B is within the values given above.

Alternatively, the high pass filter 57 and the first low pass filter 56 may be of the tracking type, that is, having the lower cutoff frequency f | and / or the upper cutoff frequency fu is not fixed, but modifiable or adjustable by respective control signals transmissible to the filters themselves. In particular, the upper and lower cutoff frequencies fi and fu may vary with varying angular tire rolling speeds. In such a case, the lower and upper cutoff frequencies can be estimated using the following equations: (D (2) where: a *: centripetal acceleration of the tire during the ith rotation; rg: inflated tire drain; m; lower harmonic component; n „: upper harmonic component.

According to equations (1) and (2), the upper and lower cutoff frequencies are multiple, according to the factors min, instantaneous angular velocity ω,> of the tire, depending on the centripetal acceleration, and the inflated radius. rg of it.

The factors m and nu consider the number of block patterns with which the outer surface of the tread 18 of the tire 11 is provided which influences the number of the vibration harmonic components of the tire itself. For example, in the case of an overall number of block patterns present in tread 18 equal to n, it can be assumed that the harmonic components of tire vibrations are equal to exactly η. The lower harmonic component's value iii is less than the n value, and the upper harmonic component's n value is greater than the n value so that they identify a range that includes the harmonic components of interest. According to a particular embodiment, the ntI value of the upper harmonic component is close to the number of block patterns n such that it is less than 2n.

For example, for various block patterns n = 70, m can be selected equal to 65 and nu is selected equal to 75. With such example lower and upper harmonic component values, for a tire angular velocity of 100 km / h, by applying equations (1) and (2), one obtains a higher cut-off frequency fi equal to 930 Hz and a lower cut-off frequency f „equal to 1,070 Hz. Alternatively, you can select the naked value such that is equal to or greater than a multiple dc n. In other words, the value nu can be equal to or greater than 2n or to another multiple of n (3n, etc.). In this way, one also takes into account the contribution to the phenomenon associated with higher order harmonics.

As will be further described below in more detail, according to the embodiment of the invention using low pass 56 and high pass 57 filters of the tracking type, the values of the lower and upper cutoff frequencies can be calculated accordingly. with equations (I) and (2) (for example with each revolution of tire 11) and then fed to the respective filters.

In the case of tracking filters and in the case of fixed cut-off frequency filters, the first low pass filter 56 and high pass filter 57 may be of a conventional type such as, for example, the discrete level type which allows adjusting the cut-off frequency not in a continuous manner but by pre-set degrees or steps according to the angular velocity of the tire. Processing stage 51 is also equipped with a second low pass filter (LPF) 54 for determining secondary parameters and a processing unit (CPU) 34 having a corresponding input terminal connected to output terminal 50 and a output terminal. corresponding output connected to the input of an analog to digital converter 53.

In general, the cutoff frequency ft of the second lowpass filter 54 is less than or equal to the lower cutoff frequency fi of the bandpass filter stage 52. Preferably, the cutoff frequency f1 is less than 300 Hz. For example, in the case of a speed dependent filter, the second low pass filter 54 has a cut-off frequency f equal to approximately 40 Hz at 20 km / h and equal to approximately 240 Hz at 100 km / h. The second low pass filter 54 may read a constant cutoff frequency ft or may be of the crawl type and may have an adjustable cutoff frequency with the angular velocity of the tire 11, in return calculable according to the invention as described. exemplarily in addition below. In particular, the cutoff frequency ft is proportional to the angular velocity tüp according to a predefined factor K: <n The factor K (eg an integer greater than 1) is dependent on the type of tire under consideration and, for example, It can be selected on the basis of its dimensions in order to extract harmonic components that describe the movement of the particular tire under consideration in a manner sufficiently with mp 1 et a.

In addition, a processing unit (CPU) 34 associated with a memory device (MEM) 35 and connected by a bus 55 to an analog to digital converter 53 is included in processing stage 51 for receiving digital values from the converter 53. Processing unit 34 made, for example using a conventional microprocessor, is such as to perform the elaboration of digital data stored in the memory device 35 and / or originating from analog to digital converter 53 for output generation, representative of roughness. of the road surface. Advantageously, this processing unit 34 can also perform a control and monitoring role for metering device 32 and the other blocks included in sensor device 3, by control signals Sc and monitoring signals Sm_ (originating from the devices or blocks being monitored) made available through relevant control / monitoring lines. For simplicity of representation, control / monitoring lines connected to corresponding components of sensor device 3 have been omitted from Figure 2. Processing unit 34 has at least one output line OU1 through which at least one output signal is provided, Sp, resulting from processing and bearing at least the information concerning the roughness of the road surface. It is noted that the measuring device 32 and some of the blocks of the processing stage 51 may also be used in order to generate, in addition to the roughness signal, also output signals carrying other deductible information from the signal produced by the measuring device itself. . For example, processing unit 34 may provide signals carrying data on the present acceleration and present angular velocity of the tire or information on other tire operating conditions such as, for example, the vertical load acting on the tire.

In addition, the sensor device 3 includes a conventional (Rx / Tx) transceiver device 31 connected to the output line OU1 and an antenna 37 to enable reception and transmission of signals to / from the fixed unit 2 installed on board the device. vehicle. Sensor device 3 is equipped with an electrical power source (PW) 33 such as, for example, a battery. However, it is possible that the processes performed within the sensor device 3 and the processing associated with the transceiver device 31 will make the battery life short compared to the life of the tire 11. Therefore, according to preferred embodiments, the Power source 33 includes a self-loading device (not shown) which generates electrical energy resulting from the mechanical stress to which the self-loading device itself is subjected (eg centrifugal force, or deformations of liner 111 or motions). due to advancement on uneven roads). For example, the self-loading device may include one or more components in piezoelectric material. The self-charging device also includes an electrical storage circuit (not shown) typically including a resistor and capacitor. As a further alternative, the sensing device 3 may be provided by the fixed unit 2 by a suitable receiving device (not shown) connected to the mobile antenna 37. Preferably, an electric power distribution device (PW-D) 36 distributes the power. provided by the power source 33 in a manner suitable for processing unit 34, memory device 35, transceiver device 31 and metering device 32, according to their requirements. ✓ It is useful to note that it is not necessary to include all components of the sensing device 3 described above (such as for example the measuring device 32, the transceiver device 31 and the processing stage 51) in the same enclosure or package. For example, the processing stage 51 and transceiver device 31 may be enclosed in a housing that is separate from that in which the metering device 32 is included and secured to other parts of the tire 11 or to the wheel (for example, the rim). 12) and associated with a cable or wireless connection (for example, by optical waves or by radio frequency). In such a case, the measuring device 32 may be placed, for example, in a casing attached to the tire similar to that shown in Figure 1 for the sensor device 3.

Figure 3 shows, using function blocks and in a very schematic manner, an exemplary embodiment of the fixed unit 2 usable in the system of the present invention. Preferably, the fixed unit 2 includes a receiver (Rx) device 26 (for example, a radio frequency receiver) connected to a fixed antenna 25 in such a manner as to enable reception of signals transmitted by the sensing device 3. Preferably, the transmitting device receiver 26 is connected to a demodulator (DEM) 27 for demodulating the received data. A memory unit (MEM) 28 such as for example an EPROM can store data received from sensor device 32 and demodulated by demodulator 27. Memory unit 28 can be associated with an additional processing unit (CPU) 24, having the role of performing the elaborations and calculations of the data received from the sensor device 3 and / or stored within the memory unit 28 and, for example, controlling the components of the fixed unit 2. In addition, the fixed unit 2 preferably includes a device Transmission and Modulation (Tx / Mod) 23 suitable for transmitting signals to the sensor device 3. The method of calculating one or more parameters representative of the roughness of the road surface or other test surface on which the tire 11 rolls, for example using sensor device 3 will now be described. The particular case in which the measuring device 32 is an acceleration sensor which returns to the output terminal 50 at least one signal Sa indicative of the time acceleration trend of the observation point P of tire 11 is considered. For example, the exemplary case where the signal Sa is representative of the radial or centripetal acceleration (ie along the Z direction) of the observation point P of tire 11 is considered. In order to better understand the following treatment. Figure 4 shows a possible trend of such an acceleration signal Sa, representing the amplitude of the eentiped acceleration az (expressed in multiples of g) as a function of the rotation angle R (variable between 0 ° and 360 “) and estimated at an angular velocity. preset U) p of tire 1 The trend of Figure 4 refers to a complete revolution performed by tire 11.

From observing the Sa signal trend, a contact area or footprint CZ is distinguished (located approximately 180 ° in the example illustrated in Figure 4), where the tire area monitored by the sensor device 3 is found to be in contact with the road. Within the contact area, the acceleration a decreases sharply until it essentially disappears, and subsequently increases. Before the tire, while rotating, moves the observation point P into the contact area CZ, that is to be found in an IN-Z (contiguous with that of the contact) entry zone where the eentipipate acceleration a is increasing. When the lookout point P leaves the contact area C-Z, the acceleration signal Sa allows the identification of an OU-Z (contiguous and contact area) output area in which the acceleration az is decreasing.

In parts of the Sa signal outside the three zones mentioned above (for example, for angles between 0 ° and 100 °), eentipeptal acceleration assumes variable values over a reduced amplitude range. The Applicant noted that for the determination of road surface roughness parameters it is particularly significant to analyze the Sa signal in close proximity to the C-Z contact area. For example, the portion of the signal that includes the IN-Z input zone, C-Z contact areas, and OU-Z output zone is of interest. In addition, the Applicant noted that the area providing the most information regarding surface roughness is the IN-Z entry zone. This result has been verified experimentally and finds a possible explanation in the fact that the IN-Z entry zone, adjoining the CZ contact area where the direct request of the tire structure by the road surface occurs, is able to "feel" the roughness-induced stress of the road surface, but is less disturbed by other phenomena associated with passing under the footprint, such as, for example, the greater or lesser flatness induced by the load.

The parts of the signal Sa on which to perform the analysis for determining the aforementioned roughness parameter are determined according to a methodology which will be described in the following, also referring to Figure 5 in addition to that of Figure 2. The output signal Sa of measuring device 32 is referred to the second low pass filter 54, which reduces or eliminates high frequency contributions and resumes a low pass filtered signal Slp. In particular, the low pass filter 54 eliminates or considerably reduces the frequency components due to the stresses borne by the road surface tire 11.

Figure 5 shows qualitatively the trend of low pass filtered signal Slp as a function of time t. In addition, for clarity, also shown in Figure 5 is tire 11, its direction of rotation and on the outer surface of the same tire are indicated the area of contact with the road surface CZ (where the tire is crushed), the zone IN-Z and the OU-Z output area.

Similar to what is said for signal Sa detected by metering device 32, the low pass filtered signal SLp has a tendency that is increasing to a first maximum pi in the IN-Z input zone. In the C-Z contact area, the low-pass filtered signal Slp has a tendency that is decreasing until it reaches a minimum value and then increases again until it reaches a second maximum value pu. In the OU-Z output area, the Slp signal has a downward trend from the second maximum pu value. The low-pass filtered signal Slp is therefore sent to the analog to digital converter 53, which resumes the corresponding digital data stored in memory 35.

Subsequently, an analysis of the stored digital data is performed to identify the first maximum pi, the second maximum pu, and the time values or coordinates ti and tu according to which such maximums are verified (evaluated from an initial time).

According to the example described, the analysis leading to the identification of the time coordinates (ti and tu) of the maxims Pi and pu is performed by processing unit 34 on the basis of a program that executes algorithms obvious to those skilled in the art. It is observed that, instead of the time coordinates, the rotation angles of the tire 11 corresponding to the aforementioned maximums can also be estimated.

According to the method of the invention, the amplitude of the IN-Z input zone is fixed taking into account the amount of data that is to be processed in the following elaborations.

For example, the inlet zone IN-Z has an extension corresponding to an angular sector (estimated at the center C of tire 11) having a prefixed angle Î ±, which may be wider with increasing tire length. For example, the angle α can be selected between 30 ° and 100 °. In the case of a car tire (for example a model 195/65 / R15 tire), a convenient value of such an angle may be about 50 °, while for a truck tire the angle may be equal to about 70 °. From the value t, corresponding to the first maximum pi, the angle oc allows the identification of another time coordinate ti (or angular), which delimits the input zone IN-Z.

Similarly, the contact area C-Z is included between the coordinates t, and tu. The OU-Z output area will be included between the time coordinate tu and another time coordinate obtained by prefixing the extension of the OU-Z output area of interest in a manner analogous to that for the IH-Z input zone. The time coordinates u, ti, tu, t: thus determined are therefore stored in memory 35.

Alternatively, the amplitude of the input zone ΪΝ-Ζ and that of the output area OU-Z may be determined, not on the basis of a predefined angular opening angular sector, but by presetting the number of samples acquired for consideration by the subsequent elaborations. It is noted that the stage of determining the time coordinates tu ti, tu, Í2 (which identify the parts of interest of the acceleration signal) can be repeated with each revolution of the tire 11.

Furthermore, it is known that for determining the time coordinates identifying the parts of interest of the acceleration signal, advantageously, an acceleration signal according to any of the X, Y, Z directions, and not necessarily the centripetal acceleration signal. may be used as described above exemplarily. The method of the invention also includes a processing stage (itself repeatable with each revolution of the tire) that leads to the estimation of the angular velocity% of the tire 11 related to a ith revolution of the same.

Advantageously, the angular velocity estimation C d is performed starting from the centripetal acceleration signal provided by the measuring device 32.

For example, for this estimation, the same low-pass filtered signal Slp, output from the second low-pass filter 54, fed to the analog-digital converter 53, can be used. Alternatively, the signal Sa present at terminal 50 can be fed directly to the analog to digital converter 53, or low-pass filtering can be performed by another filter (not shown). Analog to digital converter 53, operating in a conventional manner, takes up corresponding digital values which are then stored in memory 35. Calculation operations for determining angular velocity are performed, for example by processing unit 34 using these stored digital values. .

Preferably, the angular velocity (%) is estimated by considering the centripetal acceleration amplitude values, Î ±, assumed in the areas of interest and preferably before and after the contact area C-Z.

Referring to Figure 5, it is possible to consider the values aij and aiij of the centripetal acceleration, ai, estimated for the time coordinates t | and% i which identify the beginning of the input zone ΓΝ-Ζ and the end of the output area ou-z, on the basis of the value f (centripetal acceleration before the area of interest) and the value aus (centripetal acceleration following the area of interest), an average acceleration value aiin is calculated: (3) The angular velocity,% is therefore given by the equation: (4) Where the inflated radius rg relative to the observation point P has been pre-stored in memory 35, The value of the angular velocity e> p itself also storable in memory 35 is useful for some of the processing stages of the method of the invention. In addition, the same angular velocity value c% can be used to modify the cutoff frequency f (of the second low pass tracking filter 54, for example according to equation (Γ) indicated above. Sa acceleration, which from the output terminal 50 is fed into the bandpass filter block 52, during the rolling motion of tire 11, is now considered.The bandpass filter block 52 resumes a bandpass filtered signal. Sbp, which contains the frequency components, the origin of which is referred to the stresses induced by the texture or roughness of the road surface in the tire structure. 11. Within such a bandpass filtered signal Sbp, the frequency components due to other phenomena, not of interest, were strongly attenuated or essentially eliminated.

Figure 5 qualitatively shows a possible time trend of the Sbp bandpass filtered acceleration signal. It is noted that in the case where filter block 52 uses the first low pass filter 56 and high pass filter 57 made with tracking filters and non-constant cutoff frequency filters, processing unit 34 performs the calculation. lower and lower cutoff frequencies by applying equations (1) and (2) above, on the basis of the previously calculated angular velocity Cup and corresponding to the tire revolution considered. Processing unit 34 then sends control signals corresponding to two filters 56 and 57, which impose the calculated value for the cutoff frequency or the closest possible values allowed by the filter types to those calculated.

Subsequently, the bandpass filtered signal Sbp undergoes an analog-to-digital conversion in converter 53, which may consider conventional sampling of a given frequency fc, a quantization and a coding. The sampling frequency fc is, for example, 10 kHz, and selected according to the Nyquist theorem, and is equal to the number N of samples obtained within a given unit of time.

As previously mentioned, according to the preferred embodiment of the invention, for subsequent elaborations, the entire acceleration signal resulting from the analogue-digital conversion of the filtered bandpass signal S ^ and relative to a complete tire revolution is not. used. Advantageously, for the following elaborations, only those parts of the SBP bandpass filtered signal (or, in more detail, of the corresponding digital signal resulting from the conversion) deemed to be of interest for estimating the roughness of the road surface are taken into account. consideration.

In particular, those parts of the signal corresponding to the contact area C-Z and / or the contiguous areas, such as the IN-Z input zone and / or the OU-Z output zone are taken into account.

These parts of signal Sbp can be defined by processing unit 34 on the basis of time coordinates ti, ti, tu, t? estimated as previously described and stored in memory 35. As shown in Figure 5, the bandpass filtered signal Sbp is subdivided into a first calculation portion porção1 limited by the time coordinates ti and tu into a second limited calculation portion 52 by the time coordinates t; and you are a third calculation portion 53 limited by the time coordinates tu and t2.

It should be remembered that the angular velocity (Tire op 11 (the value of which is stored in memory 35) is associated with the angular frequency fp (number of revolutions per unit of time) by the equation: (ΰρ = 2π fp On the basis of rotational frequency fp and sampling frequency fc, the total number of samples np present in the digital signal corresponding to one revolution of the tire is estimated: npl = fc / fp For each of the three calculation parts 51, 52, 53, the number of samples taken into account is an appropriate fraction of the total value np (, correlated with the extent of the specific area of interest. For example, for a first calculation portion δΐ, a number of samples nl equal to np, / 8 may be selected.

Similarly, for the remaining calculation parts S2 and 53, a corresponding number of samples are selected to be used, n2 and n3. On the basis of these samples, a significant parameter of road surface roughness is calculated. According to the preferred embodiment of the invention, such parameter is an average of values assumed by the low pass filtered signal Sbp. In particular, the estimated parameter is a quadratic average.

In further detail, processing unit 34 performs the calculation of an energy parameter indicated by the symbol OLj (where the initials OL are derived from the term "Global Level", that is, the global surface level) expressed as a quadratic average. the amplitude values assumed by the acceleration signal and having the following equation: i5) where: - aik is the acceleration amplitude ai (radial in nature according to the example described herein) corresponding to the kth sample, - the index j (which can assume the values, 1, 2, 3) identifies the particular calculation portion δΐ, 52 or δ3 for which the OLj parameter is estimated (for example, this can be estimated for all three parts of the filtered pass signal - low Sbp digitally converted). The sum given in equation (5) is extended through the number nj of the samples as part of the jth calculation part.

As previously mentioned, the value of the parameter OLj obtained in the calculation part δΐ corresponding to the input zone 1N-Z is particularly significant of the roughness to be measured. For example, according to the particular embodiment of the invention, the estimation of parameter OLj is not performed for calculation areas δ2 and 53, but only the information deduced from the first calculation area δΐ is taken into account. Alternatively, by repeating the calculation for one or both of the other areas δ2 and δ3, it is then made possible to average the OLj parameter obtained from the first calculation area with the values of the OLj parameter deducted from the second and / or third calculation area. δ2 and / or δ3.

Advantageously, the calculation of the energy parameter OLj can be performed not only from the radial or centripetal acceleration signal Sa, but also from the acceleration signal relative to another direction or even all other directions such as the longitudinal direction X and direction. lateral Y.

Where two or three of the acceleration signals obtainable from a measuring device 32, such as a triaxial accelerometer, are used, the sensor device 3 is equipped with a suitable signal processing stage. For example, in such a case, sensor device 3 may also include at least one other filter block, analogous to block 52, for filtering the longitudinal or lateral acceleration signal. Other calculation operations may be performed by the processing unit 34 equipped with adequate processing power.

It is also noted that the calculation of the energy parameter OLj may also be performed not on an individual sensor device 3, but by many sensor devices analogous to those described and mountable at various observation points within the tire 1. The embodiment which it considers, In addition to the sensing device 3 placed on the center line of the tire 11, as shown in Figure 1, two additional sensing devices fixed laterally thereto within the tread area 18 for the sidewalls 19 and 19 ', or, for example, placed on the sides themselves, it is particularly advantageous. The sensor device 3 placed on the center line of the tire 11 is advantageous for calculating the energy parameter OLj during the advance of the vehicle in a straight line. Meanwhile, each of the sensor devices placed for the sides 19 and 19 'may be useful for calculating the energy parameter OLj during a curve.

Having three sensor devices available, it is possible to establish, for example, using appropriate software, taking into account only one of the OLj parameters provided by them. For example, it may be decided to take into account only the signal originating from one of the three installed sensing devices, which ensures the best operation under those particular operating conditions (eg on the basis of tread characteristics, convergence or curvature). The OLi parameter, as a function of tire point acceleration 11 on the frequency of interest and area of interest, is significant of the roughness of the road surface. The value of the energy parameter OLj is calculable in real time and advantageously with each tire revolution 11.

Therefore, processing unit 34 can make one or more digital signals Sp, indicative of parameter OLj and thus representative of the roughness of the road surface on which the tire 11 is rolling, available through the OUL exit line.

This Sp signal is then processed (e.g., amplified and modulated) by the transceiver device 31 which, via antenna 37, sends it to the fixed unit 2 installed on board the vehicle. It is noted that the energy parameter calculation operations described above may be performed, in whole or in part, not by the sensor device 3, but by the fixed unit 2.

A particular example of applying the method of the invention will now be described. This application will be described with reference to an experiment performed by the Applicant, but the methods with which such experiment has been performed may be used, more generally, to perform a characterization of the different roughness exhibited by road surfaces of different textures.

Three different road surfaces having different MPD parameter values ("average profile depth") were considered. The MPD parameter is an indicator commonly used to define the texture level of surfaces and is defined by ISO 13473-1 standards.

The three different road surfaces considered have the following MPD values: 0.6 ("very smooth" typology surface); 1.0 ("medium" typology surface) and 1.8 ("very rough" typology surface).

For these surfaces, the value of the energy parameter OLj was estimated with the varying angular velocity tüp of the tire using a sensing device and a calculation methodology analogous to those described above. In particular, in these tests, a tire produced by the Applicant, Pirelli model P7 225 / 55R16 was used, inflated to a pressure of 22 kPa, with a static load of 440 kg and mounted on the front right axle of a vehicle. The tests were performed at a vehicle forward speed of between 20 and 100 km / h.

In addition, in order to calculate the parameter OLj, the radial acceleration signal Sa taken from a sensor device 3 placed, not on the centerline as shown in Figure 1, but laterally with respect to the centerline of the tire, within half facing the vehicle was taken into consideration. For these experimental tests, the IN-Z input zone was taken into account. The OLj parameter was calculated (using equation (5)) in real time, with each wheel revolution, and for each of the three surfaces considered. Advantageously, a subsequent averaging operation has been performed which considers the weighting of the parameter value GLj of the individual revolution to a value of the same parameter estimated at least one revolution previously. In particular, for this average, four consecutive revolutions were considered and a variable quadratic average was performed.

Such a method has the advantage of increasing the stability of the information obtained by real-time calculation and reducing the influence of casual (or random) stresses arising from gross road surface irregularities and underlining the differences in the energy parameter OLj as a function of characteristics of the test surfaces in terms of roughness.

In detail, the average energy parameter OLj <) 0 in relation to the kth revolution gave the equation: (6) Equation (6) expresses a variable average since the values of the energy parameter it considers are updated during movement. and in particular with each revolution of the tire. The average energy parameter OLj (k) was estimated for each of the three surfaces for some angular velocity values (túj).

Subsequently, an interpolation curve of the values of the mean energy parameter OLj (k) and related to each of the three surfaces considered was identified.

For example, suitable interpolation curves are described by second degree polynomials OLj (m) within the angular velocity variable ω, having the following form: OLj (to) = acür + btt) + c Where a, b and c are the coefficients of the interpolation polynomial.

Figure 6 shows the interpolation curves € 1 (relative to very smooth surface), € 2 (relative to medium surface) and C3 (relative to very rough surface) obtained under the experimental conditions indicated above. Near each curve C1, C2 and C3 are the numerical values of coefficients a, b and c (left to right). Each curve in Figure 6 compares the angular velocity 0) p expressed in rad / s (indicated on the X axis) with mean energy parameter values (on the Y axis).

From the observation of Figure 6, a clear distinction of the Cl, C2 and C3 curves is noted, especially for angular velocity values greater than 40 rad / s, and it can be ascertained that the energy parameter values are much higher for the surface. very rough (curve C3), less for the average surface (curve C2) and even less for the very smooth surface (curveCl).

This result shows how the calculation of the energy parameter performed according to the invention is effectively significant of the road surface texture.

According to a preferred embodiment of the invention, digital data corresponding to curves C1, C2 and C3 are stored in the memory 28 of the fixed unit 2 in such a way as to constitute reference curves in order to allow the characterization of the road surface in which mobile vehicle is found. For example, the interpellation curve formula and the corresponding interpolation coefficients can be stored in memory. The sensor device 3 may transmit, for example for each wheel revolution, a signal corresponding to the calculated value of the energy parameter OLj (estimated according to equation (5)) together with another signal containing the tire angular velocity value ( estimated according to equation (4)). The fixed unit processing unit can receive these signals and use the energy parameter and angular velocity values as coordinates of a point D to be identified in the diagram in Figure 6.

Given this curve, between the Cl, C2 and C3 curves that is closest to point D, the type of surface on which the vehicle is found can be classified and establish whether someone is dealing with a very smooth, medium or very rough surface.

This information may be made available by the fixed unit 2 to another apparatus placed on board the vehicle such as, for example, an ABS control system which may therefore operate on the basis of additional descriptive information of the vehicle's movement conditions and modify , for example, one or more operating parameters that influence the behavior of the vehicle itself.

Figure 7 shows a diagram with three Cl ', C2' and C3 'curves obtained analogously and under the same experimental conditions as described for the Cl, C2 and C3 curves of the diagram in Figure 6 and at least for the fact that the parameter of The mean energy OLj (k) was estimated from the non-radial but longitudinal X acceleration signal provided by the measuring device 32. In Figure 7, next to each interpolation curve, the values of the coefficients a, b and c that define the second interpolation polynomial of corresponding degree used for the specific experimental test. For the Cl ', C2' and C3 'curves, the same considerations regarding the distinctiveness of the three surface typologies made for those of Figure 6 are valid.

This shows how the method of the invention, although described with reference to the radial acceleration signal, is valid even when using an acceleration signal referring to the other directions of the tire.

Figure 8 shows interpolation curves obtained with the method described above and under the same experimental conditions (by processing a radial acceleration signal) in the same Cartesian plane for three different tire models: Pirelli P6000 205 / 55R16, Pirelli P7 205 / 55R16 (as used for the curves in Figure 6) and Pirelli Pzero 205 / 55R16.

Figure 8 shows three families of curves, where each curve corresponds to one of the models listed above: the family Fl, related to the very smooth surface; the F2 family, related to the medium surface, the F3 family, related to the very rough surface.

From the observation of Figure 8 it is observed that, varying with the tire model, a clear distinction between the estimated family of curves for the three different surfaces is still observed, especially above an angular velocity of approximately 40 rad / s.

The three curves of each family do not differ much from each other. In other words, the methodology described above for information on the roughness of the rolling surface on which the tire is rolling appears to be essentially independent of the tire structure. Nevertheless, the Applicant believes that for the characterization of the road surface on which a vehicle travels, having a particular tire model, it is more convenient to memorize the reference curves obtained from measurements performed using the same tire model.

According to a further embodiment of the present invention, during the movement of the vehicle it is possible to store the energy parameter values OLj with reference to various tire revolutions in order to estimate the variance (or the mean square difference) of these. values in order to obtain information on the general characteristics of a long section of road such as, for example, indications of the uniformity or irregularity of the surface of the considered road section.

The teachings of the present invention are particularly advantageous in that they allow the determination of a parameter that characterizes the texture / roughness of the surface on which the moving vehicle is found. This parameter is of significant importance if, for example, it is then made available to an onboard system such as an ABS (Anti-Lock System) control system.

Claims (48)

Method for determining the roughness of a rolling surface on which a tire (11) is rolling, characterized in that it includes the step of: - providing, by means of a sensor device (3) operatively associated with the tire ( 11) a first signal (Sa) representative of the movement of at least one point (P) of the tire during its rolling on the surface; said first signal (Sa) being an acceleration signal representative of said at least one point of the tire during its rolling on the surface; processing the first signal to provide an output (OUl) indicative of the roughness of said rolling surface on which the tire is rolling, said processing step including the step of: determining at least a first tcmporal / angular coordinate corresponding to a first portion of the first signal associated with a tire rolling step, wherein said at least one point is in a contiguous zone (IN-Z; OU-Z) with a tire contact zone (CZ) with the rolling surface. Method according to claim 1, characterized in that the processing step includes a frequency filtering step of the first signal (Sa) to extract one. second signal (Sbp) representative of movement components of said at least one point due to deformations suffered by the tire during rolling. Method according to claim 2, characterized in that the processing step includes a data processing step of at least a portion (Sl) of said second signal to calculate at least one parameter indicative of the roughness of the surface. Scrolling. Method according to claim 1, characterized in that said acceleration signal is representative of at least one of the following accelerations of at least one tire point: radial acceleration, longitudinal acceleration, lateral acceleration. A method according to claim 1, characterized in that the first signal is representative of the movement of said at least one point (P) during a tire revolution (11), said processing step including the step of: determining second temporal / angular coordinates corresponding to a second portion of the first signal associated with a tire rolling step, wherein said at least one point is in said tire contact zone (CZ) with the rolling surface. Method according to claim 5, characterized in that said contiguous zone is an inlet zone (IN-Z) preceding said contact zone (C-Z) according to the direction of rotation of the tire. Method according to claim 6, characterized in that said inlet zone (IN-Z) corresponds to an angular sector of the tire having a predetermined opening angle. Method according to claim 1, characterized in that the processing step includes a step of estimating the angular velocity of the tire (11) during its rotation. Method according to claim 8, characterized in that the estimation step includes a step of calculating the angular velocity on the basis of at least one value of the centripetal acceleration of the tire and on the basis of the tire radius. Method according to claims 1 and 3, characterized in that the processing step includes a step of defining said at least a portion (δΐ) of the second signal (Sbp) on the basis of said temporal / angular coordinates, dictates at least a portion corresponding to one between the contact zone (CZ) and the contiguous zone (IN-Z). Method according to claim 3, characterized in that the processing step includes the steps of: - filtering the first signal to extract the second signal (Sbp), - performing an analog to digital conversion to obtain corresponding digital data said second signal; - elaborate at least part of said digital data and provide an output signal taking the current parameter indicative of the roughness of the surface on which the tire roll occurs. Method according to claim 11, characterized in that said step of elaborating at least part of the digital data includes a calculation of an average of values associated with a preselected number of digital samples. Method according to claim 11, characterized in that it further includes a data pre-storage step (a, b, c) defining at least a first reference curve representative of a first bias of the roughness parameters. measured at the varying angular velocity of the tire, the first reference curve being indicative of a first class of roughness associated with a first reference rolling surface. A method according to claim 13, characterized in that it further includes an additional data pre-storage step (a, b, c) defining a second reference curve representative of a second trend of measured roughness parameters. with the varying angular velocity of the tire, the second reference curve being indicative of a second roughness class distinct from the first class and associated with a second reference rolling surface. Method according to claim 13, characterized in that it further includes the steps of: - receiving the output signal taking the current parameter; - receive an additional output signal indicative of the current angular velocity assumed by the tire essentially during the measurement of the current parameter; - perform a comparative elaboration of the current parameter with the values of said at least first reference curve in such a way as to establish a roughness typology to which the surface on which the tire roll is taking place belongs essentially during the parameter measurement comparative elaboration being performed taking into account the present angular velocity. 16. Method for controlling the behavior of a vehicle to which at least one tire is fitted, characterized in that it includes the steps of: - determining the roughness of a tire rolling surface (11) according to a a method as defined in at least one of the preceding claims; - make the roughness information available to a vehicle control system. Method according to claim 16, characterized in that said control system is an ABS (Anti-Lock System) system. 18. A system for determining the roughness of a rolling surface of a tire (11) to be mounted on a vehicle, the system being operably associable with the tire and comprising: - an associated sensing device (3, 32) operatively with the tire (11) to provide a first signal (Sa) representative of the movement of at least one point (P) of the tire while rolling said tire on a surface having a respective roughness, said sensing device including an accelerometer and the first signal (Sa) being an acceleration signal representative of the acceleration of said at least one tire point during surface rolling, - a processing stage (51, 2) of the first signal to generate an output (OUl) indicative of the roughness of said rolling surface on which the tire is rolling, the processing stage (54, 53, 34) in order to process the first signal (Sa) to determine the temporal / angular coordinates corresponding to: - a first the portion of the first signal associated with a tire rolling step wherein said at least one point is found in a contiguous zone (IN-Z; OU-Z) to a zone of contact of the tire with the rolling surface. A system according to claim 18, characterized in that the processing stage is such as to perform frequency filtering of the first signal (Sa) to extract the second signal (Sbp) representative of said motion components. at least one point due to tire deformation during rolling. A system according to claim 19, characterized in that the processing stage is such as to perform an elaboration of at least a portion of said second signal to calculate at least one parameter indicative of the roughness of the scroll surface. A system according to claim 18, characterized in that said acceleration signal is representative of at least one of the following tire accelerations: radial, longitudinal, lateral. System according to claim 18, characterized in that the first signal is representative of the movement of said at least one point (P) during a revolution of the tire (11) and the processing stage (54, 53, 34). ) is for processing the first signal (Sa) to determine temporal / angular coordinates corresponding to: - a second portion of the first signal associated with a tire rolling step wherein said at least one point is found in said contact zone (CZ) of the tire with the rolling surface. System according to claim 22, characterized in that said contiguous zone is an inlet zone (IN-Z) preceding said contact zone (C-Z) according to the direction of rotation of the tire. A system according to claim 23, characterized in that said inlet zone (IN-Z) corresponds to an angular sector of the tire having a predetermined opening angle. A system according to claim 18, characterized in that the processing stage is for estimating the angular velocity of the tire (11) assumed during its rotation. A system according to claim 25, characterized in that the processing stage is for estimating the angular velocity on the basis of at least one centripetal acceleration value of the tire and on the basis of a tire radius. System according to claims 19 and 21, characterized in that the processing stage is for identifying said at least a portion (δΐ) of the second signal (SBp) on the basis of said temporal / angular coordinates, said at least a portion corresponding to one between the contact area (CZ) and the contiguous area (IN-Z). System according to claim 19, characterized in that said processing stage includes a bandpass filtering block (52) for providing said second signal from the first signal. The system of claim 28, further comprising: - an analog to digital converter (53) for obtaining digital data corresponding to said second signal (SBp) and having a preset sampling frequency associated therewith; a memory device (35) for storing at least said digital data. A system according to claim 29, characterized in that said processing stage includes a processing unit (34) for processing at least part of said digital data and providing at least one parameter indicative of the scroll surface roughness. . A system according to claim 28, characterized in that said bandpass filtering block (52) has an included bandwidth between 300 Hz and 5,000 Hz. A system according to claim 31, characterized in that said band-pass filtering block (52) has a through-band included between 300 Hz and 2500 Hz. A system according to claim 28, characterized in that said filter block includes at least one tracking filter (56, 57) having a modifiable respective cutoff frequency (fi, fu) as a function of the angular velocity of tire rotation is correlated with a factor dependent on the number of block patterns present in the tread of said tire. A system according to claims 27 and 30, characterized in that it dictates at least a portion of the samples to be processed by the processing unit is determined as a function of said sampling frequency and as a function of the extension of one between said contiguous zone and said contact zone. A system according to claim 18, characterized in that said sensing device is predisposed to be fixed to the tire. A system according to claim 34, characterized in that it further includes a transmitting device (31) connected to said processing stage (51) and equipped with a first antenna (37) in order to radiate at least one signal. external. A system according to claim 36, characterized in that said at least one external signal carries the information content of the first signal. A system according to claim 36, characterized in that said at least one external signal carries information indicative of the roughness of the rolling surface on which the tire is rolling. A system according to claim 36, characterized in that said at least one external signal includes a velocity signal representative of the present angular velocity of the tire during its rolling. A system according to claim 37, characterized in that it further includes: - a fixed unit (2) installable on a vehicle and including a second antenna (25) coupled to a receiving device (25) in order to receive said external signal; - an additional processing unit connected to a receiving device for processing the received external signal. A system according to claim 18, characterized in that said sensor device is arranged to be fixed to a tire support rim (12). 42. Tire (11) for a vehicle, characterized in that it includes a sensor device (3) operatively associated with the tire to provide a first signal (Sa) representative of the movement of at least one point (P) of the tire during rolling. said tire on a surface having a respective roughness, said sensor device including an accelerometer and the first signal (Sa) being an acceleration signal representative of the acceleration of said at least one point of the tire during rolling on the surface, said sensor device comprising a processing stage (51) of the first signal to generate an output (OUl) indicative of the roughness of said rolling surface on which the tire is rolling, the processing stage (54, 53, 34) of processing the first signal (Sa) in order to determine the temporal / angular coordinates corresponding to: - a first portion of the first signal associated with a tire rolling step wherein said at least one point is found in a contiguous zone (IN-Z; OU-Z) to a zone of contact of the tire with the rolling surface. Tire according to claim 42, characterized in that the processing stage is for performing frequency filtering of the first signal (Sa) to extract a second signal (Sbp) representative of said at least one moving component. point due to tire deformation during rolling. Tire according to claim 43, characterized in that the processing stage is for processing at least a portion of said second signal to calculate at least one parameter indicative of the roughness of the rolling surface. Tire according to Claim 42, characterized in that said acceleration signal is representative of at least one of the following tire accelerations: radial, longitudinal, lateral. Tire according to Claim 42, characterized in that the sensor device includes a housing fixed to a wall inside the tire by means of a fastener (332). Tire according to claim 42, characterized in that it includes at least one additional sensing device operably associable with the tire to provide an additional corresponding signal (Sa) representative of the movement of at least one additional point of the tire during rolling. of said tire on the surface. Wheel, characterized in that it includes a support rim (12) and a tire (II) as defined in at least one of claims 42 to 47 associated with said support rim.