Wear Sensing and Wear Sensors

Abstract

A method for determining wear of a textured layer bonded to a base layer is disclosed, the base layer being disposed between the textured layer and the ultrasonic transducer, the textured layer having recesses and protrusions. The method includes the steps of emitting ultrasonic waves toward the recesses and protrusions with the ultrasonic transducer, receiving ultrasonic echoes of the emitted ultrasonic waves reflected by the recesses and protrusions of the textured layer with the ultrasonic transducer, and determining a height difference between the recesses and protrusions based on the received ultrasonic echoes. The present invention also relates to a device for determining wear of a textured layer bonded to a base layer, and a product comprising said device.

Description

[Technical Field]

[0001] The present invention generally relates to sensing wear in a textured layer bonded to a base layer using ultrasound. [Background technology]

[0002] Patent Document 1 relates to a large, centrally open rolling bearing consisting of a single-piece or multi-piece outer and inner rings and rolling elements disposed between the rings that roll on tracks. In this bearing, one ring is designed to accommodate an ultrasonic probe, while the other ring has a coupling surface. One or more rolling coupling surfaces are disposed on one or more outer surfaces of the ring to be tested. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] European Patent Application Publication No. 0413119 Summary of the Invention [Means for solving the problem]

[0004] One aspect of the present invention relates to a method for determining wear of a textured layer bonded to a base layer comprising an ultrasonic transducer, the base layer being disposed between the textured layer and the ultrasonic transducer, the textured layer comprising recesses and protrusions. The method comprises: emitting ultrasonic waves toward the recessed portion and the protruding portion by an ultrasonic transducer; receiving, by an ultrasonic transducer, ultrasonic echoes of the emitted ultrasonic waves reflected by the recesses and protrusions of the textured layer; and determining a height difference between the recessed portion and the protruding portion based on the received ultrasonic echoes.

[0005] It will be appreciated that the present invention can mitigate (or even cancel) the effects of external temperature for determining wear of a textured layer using an ultrasonic transducer. External temperature fluctuations may cause, for example, thermal expansion of the base layer and / or the transducer. The present invention can also mitigate (or even cancel) problems commonly encountered when, for example, a complex interface exists between the base layer and the textured layer. It will also be appreciated that the present invention can remotely measure wear of a textured layer, in the sense that the ultrasonic transducer does not need to be directly attached to the textured layer. The textured layer may be placed in a hostile environment, and therefore a transducer attached to this hostile environment may not operate properly. Therefore, the present invention allows for in situ wear measurements to be performed even when the textured layer is placed in a hostile environment (thereby avoiding contamination, wear, and / or damage to the transducer).

[0006] The frequency of the emitted ultrasound may be between 20 kHz and 1000 MHz, preferably between 50 kHz and 500 MHz, and even more preferably between 100 kHz and 10 MHz.

[0007] The ultrasonic transducer may comprise (or consist of) a piezoelectric transducer.

[0008] In one embodiment, the step of determining the height difference includes determining a time difference (i.e., delay) between echoes reflected by the recess and the protrusion, and the determination of the height difference is based on the determined time difference.

[0009] Optionally, the step of determining the height difference comprises determining an absorption between echoes reflected by the recess and the protrusion, and the determination of the height difference is based on the determined absorption.

[0010] In one embodiment, the method further comprises determining a frequency of a resonant peak of the textured layer bonded to the base layer, wherein the frequency of ultrasonic waves emitted by the ultrasonic transducer is substantially equal to the determined frequency of the resonant peak. The frequency of the emitted ultrasonic waves is preferably the full width at half maximum (FWHM) of said resonant peak, more preferably within a frequency that provides a maximum attenuation of −2 dB relative to the peak's maximum, and most preferably within a frequency that provides a maximum attenuation of −1 dB relative to the peak's maximum. Optionally, determining the resonant peak comprises sampling the response of the textured layer bonded to the base layer at multiple frequencies, for example by emitting multiple ultrasonic waves at different frequencies.

[0011] The method may include determining a phase shift between ultrasonic echoes reflected by recesses and protrusions of the textured layer, and determining a height difference between the recesses and protrusions may be based on the determined phase shift.

[0012] In one embodiment, the method may further include comparing the determined frequency of the resonant peak of the textured layer bonded to the base layer with expected frequencies of the resonant peak, for example stored in a database.

[0013] Determining the height difference may include mapping the received ultrasonic echoes to a height difference using a lookup table, database, and / or artificial intelligence model that maps the received ultrasonic echoes to a height difference between the recess and protrusion.

[0014] The method may also include communicating the determined height difference to a remote receiver, for example, via at least one of Bluetooth®, Bluetooth Low Energy®, Zigbee®, Z-Wave®, NFC®, RFID®, and 6LoWPAN® protocols.

[0015] The base layer may comprise a metallic material such as aluminum, copper, iron, tin, gold, lead, silver, titanium, uranium, and zinc, or any combination thereof. The base layer may comprise a composite material such as reinforced concrete or a fiber-reinforced polymer (e.g., carbon fiber-reinforced polymer, glass-reinforced plastic). The polymer may be a thermoplastic polymer or a thermosetting polymer. An example thermosetting composite may incorporate aramid and carbon fibers in an epoxy resin matrix. Typically, one of the components of the composite may be structured, for example, as a mesh or the like. Typical examples of the base layer may include stone, steel, PMMA, nylon, and aluminum dibond (a layer of LDPE sandwiched between two layers of aluminum).

[0016] The textured layer may comprise (or consist of) silicone foam, natural rubber (possibly including polyester), polychloroprene (neoprene), polyurethane, acrylic, alkyd enamel, acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM / acetal), fluoropolymers (PTFE, PFA, PVDF, FEP, ETFE), polysulfone (PAS, PPS / PPSU, PES, PSU, PSF), polyetherimide (PEI), polyaryletherketone (PAEK), polyamideimide (PAI), polyimide (PI), inorganic enamel and inorganic ceramic, as well as combinations of the foregoing layer materials as mixtures or as individual phases.

[0017] The angle of incidence of the emitted ultrasound may be substantially normal to the surface of at least one of the recess and protrusion, and preferably should not deviate from normal incidence by more than 10°, more preferably should not deviate from normal incidence by more than 5°, and even more preferably should not deviate from normal incidence by more than 2°.

[0018] The emitted ultrasound may be pulsed ultrasound. Alternatively, the emitted ultrasound may be continuous ultrasound. Of course, the ultrasound transducer may emit pulsed ultrasound and continuous ultrasound, possibly sequentially.

[0019] The method may preferably comprise, as an alternative to determining the height difference, storing the frequency of a resonant peak of the textured layer bonded to the base layer, for example in a database. In one embodiment, multiple resonant peaks may be stored.

[0020] A further aspect of the present invention relates to a device for determining wear of a textured layer affixed to a base layer, the textured layer comprising recesses and protrusions. The device comprises: an ultrasonic transducer configured to emit ultrasonic waves toward the recesses and protrusions and to receive ultrasonic echoes of the emitted ultrasonic waves reflected by the recesses and protrusions of the textured layer; a controller configured to determine a height difference between the recessed portion and the protruding portion based on the received ultrasonic echoes.

[0021] Determining the height difference may include determining a time difference between echoes reflected by the recess and the protrusion, the determination of the height difference being based on the determined time difference.

[0022] Determining this height difference may include determining an absorption between echoes reflected by the recess and the protrusion, and determining the height difference is based on the determined absorption.

[0023] In one embodiment, a controller is operably connected to the ultrasonic transducer, the controller being configured to determine a frequency of a resonant peak of the textured layer bonded to the base layer. The controller may be configured to operate the ultrasonic transducer to emit ultrasonic waves at a frequency substantially equal to the determined frequency of the resonant peak. The frequency of the emitted ultrasonic waves is preferably within a full width at half maximum (FWHM) of the resonant peak, more preferably within a frequency that provides a maximum attenuation of −2 dB relative to the peak's maximum, and most preferably within a frequency that provides a maximum attenuation of −1 dB relative to the peak's maximum.

[0024] The controller may be further configured to determine a phase shift between ultrasound echoes reflected by the recesses and protrusions of the textured layer, and determining a height difference between the recesses and protrusions may be based on the determined phase shift.

[0025] The controller may be configured to compare the determined frequencies of the resonant peaks of the textured layer bonded to the base layer with expected frequencies of the resonant peaks, for example stored in a database.

[0026] Determining the height difference may include mapping the received ultrasonic echoes to a height difference using a lookup table, database, and / or artificial intelligence model that maps the received ultrasonic echoes to a height difference between the recessed portion and the protrusion, which mapping may be performed by a controller.

[0027] The weight of the device may be between 1g and 10g, preferably between 2g and 9g, and most preferably between 3g and 7g.

[0028] The device may further comprise a transmitter selected from the group consisting of a Bluetooth® transmitter, a Bluetooth Low Energy® transmitter, a Zigbee® transmitter, a Z-Wave® transmitter, an NFC® transmitter, an RFID® transmitter, and a 6LoWPAN® transmitter, the transmitter configured to communicate the determined height difference to a remote receiver. The transmitter is controlled by a controller such that the controller can operate the transmitter to communicate the determined height difference to the remote receiver. In one embodiment, the controller may determine whether the determined height difference is below or above a threshold. If the determined height difference is below the threshold, the controller may operate the transmitter to emit an alarm signal in addition to or as an alternative to the determined height difference.

[0029] The controller may preferably be configured to store, eg in a database, the frequencies of the resonant peaks of the textured layer adhered to the base layer as an alternative to determining the height difference.

[0030] A further aspect of the present invention relates to an article of manufacture comprising a device as disclosed herein, the article comprising a textured layer and a base layer, the textured layer affixed to the base layer and the base layer disposed between the textured layer and an ultrasound transducer of the device, the textured layer comprising recesses and protrusions.

[0031] The ultrasonic transducer may be embedded in the base layer.

[0032] As used herein, the verb "comprise" and the phrase "consisting of" are used as open transitions meaning "including" or "consisting of at least." Unless otherwise indicated by context, the use of the singular is intended to encompass the plural, except when the cardinal number "1" is used. That is, "1" in this case means "exactly one." Ordinal numbers ("first," "second," etc.) are used herein to distinguish between different instances of a general object; no particular order, importance, or hierarchy is intended by their use. Furthermore, when multiple instances of an object are referred to by an ordinal number, this does not necessarily mean that no other instances of that object are present (unless the context clearly indicates otherwise). When reference is made to "one embodiment," "an embodiment," "multiple embodiments," etc., this means that these embodiments can be combined with each other. An embodiment may relate to various aspects of the invention unless the context clearly indicates that it is incompatible with a particular aspect. Furthermore, features of these embodiments can be used in the combinations specified, and further, these features can be combined between embodiments without departing from the invention, unless the context clearly indicates that the combination is not possible.

[0033] Preferred, non-limiting embodiments of the present invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a schematic representation of a product according to one aspect of the present invention. [Figure 2] FIG. 1 illustrates a typical response to ultrasonic excitation of a base layer bonded to a textured layer. [Figure 3] 1 is a plot showing a typical response to ultrasonic excitation of a base layer bonded to a textured layer. [Figure 4]FIG. 1 illustrates a typical response to ultrasonic excitation of a base layer bonded to a textured layer. [Figure 5] FIG. 1 illustrates a typical response to ultrasonic excitation of a base layer bonded to a textured layer. [Figure 6] FIG. 1 illustrates a typical response to ultrasonic excitation of a base layer bonded to a textured layer. DETAILED DESCRIPTION OF THE INVENTION

[0035] The reader is advised that the drawings are not to scale. Additionally, for clarity, height, length, and / or width proportions may not be drawn precisely.

[0036] 1 shows an article 10 comprising a device 12, a base layer 14, and a textured layer 16. The textured layer 16 is secured to the base layer 14, for example, by adhesive, gluing, laminating, etc. Additionally, the textured layer 16 can be obtained by etching or, in other words, machining the base layer 14.

[0037] On the opposite side of the textured layer 16 is the device 12. The device 12 includes an ultrasonic transducer 18 (e.g., a piezoelectric transducer), which is in direct contact with the base layer 14. In other words, the base layer 14 is disposed between the textured layer 16 and the ultrasonic transducer 18 of the device 12. In one embodiment, the ultrasonic transducer 18, or even the entire device 12, may be embedded (at least partially or entirely) in the base layer 14. The ultrasonic transducer 18 may be affixed to the base layer 14, for example, by adhesive or gluing.

[0038] Textured layer 16 includes recesses 20 and protrusions 22 on the surface opposite base layer 14 .

[0039] The base layer 14 may comprise a metallic material such as aluminum, copper, iron, tin, gold, lead, silver, titanium, uranium, and zinc, or any combination thereof. The base layer 14 may also comprise a composite material such as reinforced concrete or a fiber-reinforced polymer (e.g., carbon fiber-reinforced polymer, glass-reinforced plastic). The polymer may be a thermoplastic polymer or a thermosetting polymer. An example thermosetting composite may incorporate aramid and carbon fibers in an epoxy resin or rubber matrix. Typically, one of the components of the composite may be structured as, for example, a mesh or equivalent, which may or may not be metallic. Typical examples of base layers may include stone, steel, PMMA, nylon, and aluminum dibond (a layer of LDPE sandwiched between two layers of aluminum). The base layer 14 may be composed of multiple sub-layers.

[0040] The textured layer may comprise (or consist of) silicone foam, natural rubber (possibly including polyester), polychloroprene (neoprene), polyurethane, acrylic, alkyd enamel, acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM / acetal), fluoropolymers (PTFE, PFA, PVDF, FEP, ETFE), polysulfone (PAS, PPS / PPSU, PES, PSU, PSF), polyetherimide (PEI), polyaryletherketone (PAEK), polyamideimide (PAI), polyimide (PI), inorganic enamel and inorganic ceramic, as well as combinations of the foregoing layer materials as mixtures or as individual phases.

[0041] In one embodiment, the composition of base layer 14 is different from the composition of textured layer 16 .

[0042] The ultrasonic transducer 18 is controlled by the controller 24. When operated by the controller 24, the ultrasonic transducer 18 may emit one or more ultrasonic waves toward the textured layer 16 and the base layer 14. The one or more ultrasonic waves may be pulsed ultrasonic waves, continuous ultrasonic waves, or a combination thereof. In particular, the ultrasonic transducer 18 may emit one or more ultrasonic waves toward the recesses 20 and the protrusions 22.

[0043] The one or more ultrasonic waves propagate through the base layer 14 and the textured layer 16. The one or more ultrasonic waves may then be reflected, for example, by the interface between the base layer 14 and the textured layer 16, thereby generating a first reflected wave r1. Furthermore, the one or more ultrasonic waves may be reflected by the interface between the textured layer 16 and the medium within which the textured layer resides, thereby generating further reflected waves r2 and r3. These reflected waves r1, r2, and r3 may then be received by the ultrasonic transducer 18.

[0044] These reflected waves received by the transducer are echoes of the emitted ultrasonic wave or waves that are reflected by the interface as disclosed above.

[0045] These received waves may then be processed by the controller 24 to determine, for example, the height difference between the recessed portion 20 and the protrusion portion 22, based on, for example, the time difference (delay) Δt of the reception of the ultrasonic echoes and / or the absorption of the emitted ultrasonic echoes. A typical height difference may be between 0.01 mm and 30 mm, preferably between 0.1 mm and 5 mm, and most preferably between 0.2 mm and 3 mm.

[0046] Additionally, the device may include a transmitter 26 selected from the group consisting of a Bluetooth® transmitter, a Bluetooth Low Energy® transmitter, a Zigbee® transmitter, a Z-Wave® transmitter, an NFC® transmitter, an RFID® transmitter, and a 6LoWPAN® transmitter. The transmitter may be configured to communicate to a remote receiver, for example, the determined height difference and / or any information provided by the controller, such as the location of one or more resonant peaks. The controller may be configured to operate the transmitter 26.

[0047] Additionally, the device may include a power supply (AC) 28 for powering the components of the device. The controller 24 serves as a power management system for the device 12 and is configured to power, for example, the ultrasonic transducer 18, the transmitter 26, or other components via the power supply (AC) 28.

[0048] The controller may operate the device through specific programming or by being specially designed hardware, for example an application specific integrated circuit (ASIC), digital signal processor (DSP), or programmable logic circuit (e.g., FPGA, etc.) The controller may include or have access to memory for providing the persistence layer.

[0049] The weight of the device may be between 1 g and 10 g, preferably between 2 g and 9 g, and most preferably between 3 g and 7 g. The dimensions of the device may be in the range of 5 mm to 20 mm, preferably between 6 mm and 15 mm, and even more preferably between 8 mm and 10 mm. The thickness of the device may be in the range of 1 mm to 10 mm, preferably between 2 mm and 7 mm, and even more preferably between 3 mm and 5 mm. During operation, the power consumption of the device may be as low as 1 mW to 100 mW, for example, as low as 10 mW to 50 mW, and even more preferably as low as 20 mW to 40 mW.

[0050] 2 shows a typical signal acquired by an ultrasonic transducer upon emission of an ultrasonic pulse as disclosed above. Four peaks are detected by this ultrasonic transducer 18. The first peak is for the emitted wave, with delays in reception order, echoes r1, r2, and r3. The time Δt between r2 and r3 provides an indication of the height difference between the recess and protrusion. Furthermore, the absorption difference between the two peaks can provide an indication of such height difference.

[0051] By providing a differential measurement of the textured layer, the present invention allows for mitigating (even canceling out) the effects of external temperature for determining wear of the textured layer using an ultrasonic transducer. Furthermore, this differential measurement allows for canceling out any complications arising from the base layer (e.g., complex interfaces between the base layer and the textured layer). It will be further appreciated that the device according to the present invention allows for in situ probing of the product while being indirect in the sense that there is no direct contact with the textured layer.

[0052] In the context of this specification, wear to the textured layer can take many forms, such as material loss (which reduces the thickness of the textured layer), ridges, impurities, contaminants (e.g., additional layers such as biofilm), defects (e.g., cracks, corrosion), etc. In other words, wear relates to changes in the textured layer during use relative to the textured layer as intended and manufactured at the factory.

[0053] 3 shows an example of measurements that can be obtained by using device 12 to probe textured layer 16 attached to base layer 14. Here, the following are plotted: Top left:s 11 s for the real part of 11 Nyquist plot of the imaginary part of Top center: S versus radiated ultrasonic frequency 11 Bode plot of the absolute value of . Top right: Bode plot of the absolute value of Z versus the emitted ultrasonic frequency. Bottom left: Nyquist plot of the imaginary part of Z against the real part of Z. Bottom center: s vs. emitted ultrasonic frequency 11 Bode plot of the phase of Bottom right: Bode plot of the phase of Z versus the emitted ultrasonic frequency.

[0054] This s 11 The absolute value of s (known as the reflection coefficient) represents the reflected power from the textured layer 16 attached to the base layer 14, while s 11 The phase of indicates the phase shift of the reflected wave relative to the emitted wave. Z corresponds to the impedance of the ultrasonic transducer, which can vary depending on the received ultrasonic wave.

[0055] For each plot, three samples were probed: the first sample was the original stone tile alone as the base layer (triangles), the second sample was the stone tile with layer A attached (squares), and the third sample was the stone tile with layer B attached (lines).

[0056] The stone tiles are 7 mm thick, layer A is a 3.2 mm thick silicone foam (RS stock number: 733-6810) and layer B is a 1.5 mm thick natural rubber sheet (RS stock number: 506-3078) with a polyester insert in the middle. This natural rubber has a density of 1.5 g / cm 3 It has a density of

[0057] These plots show a resonance peak at approximately 1 MHz, which provides better resolution for determining height difference or absorption.

[0058] Figure 4 is a close-up of the plot near the resonance peak in the lower right of Figure 3. This plot shows the phase difference caused by the difference in layer thickness (or the lack of a difference in thickness). This phase difference can then be mapped to a height difference, for example, by using a look-up table, database, and / or artificial intelligence model that maps this phase difference. Note that this phase difference is directly related to the time difference by the speed of sound in a particular medium.

[0059] The lookup tables, databases, and / or artificial intelligence models may be accessed locally, for example, with a persistence layer located in the persistence layer of the controller, or may be accessed remotely, for example, via communication from / to the transmitter to a remote server comprising the lookup tables, databases, and / or artificial intelligence models.

[0060] It is worth noting that the frequency shift Δf of the resonant peak occurs depending on the material adhered to the base layer (layer A or layer B), thereby making it possible to determine whether this adhered layer is in fact the expected layer. This may be particularly advantageous for determining whether a small foreign object made of a material different from the base layer 14 and the textured layer 16 is lodged in the recess. The detection of a small foreign object in the recess may also indicate that the determined height difference may not be accurate. Furthermore, one or more additional layers, such as, for example, a biofilm, may form on the textured layer during wear. Such presence of a biofilm may be detected by the present invention, since the resonant peak may be shifted.

[0061] In Figure 5, three samples were probed: the first sample is the original stone tile only as a base layer (circle), the second sample is the stone tile with layer B attached (cross), and the third sample is the stone tile with two layers B attached (line).

[0062] Figure 5 shows the phase difference recorded due to the difference between the thickness of one layer B and the thickness of its second layer B. Again, the height difference can be determined by mapping as disclosed above. Furthermore, as expected, no frequency shift occurs.

[0063] Additionally, other materials may be probed, as shown in Figure 6, where an aluminum die bond composite (a layer of LDPE sandwiched between two aluminum layers) is used as the base layer onto which either layer A or layer B is adhered. Again, if another material is detected, a frequency shift can be determined. Additionally, as previously mentioned, a phase shift can also be determined.

[0064] It should be noted that a similar analysis can be performed using other plots such as |s11| versus frequency and |Z| versus frequency, which represent the absorption of the emitted wave.

[0065] In some embodiments, multiple transducers may be used, for example, a first transducer may be configured to emit ultrasound waves toward the recessed portion and a second transducer may be configured to emit ultrasound waves toward the protruding portion.

[0066] This product may be parquet siding (e.g. wear and tear, loss of protective varnish), a boat hull (e.g. loss of protective paint or biofilm build-up), a fluid supply pipeline (e.g. corrosion, loss of internal protective coating), a wall masonry (e.g. loss of paint or protective coating), a glass window (e.g. loss of protective infrared or UV coating), a swimming pool liner or composite wall section (e.g. loss of protective rubber coating), with the advantage that the device 12 is protected and never exposed to harsh environments.

[0067] While particular embodiments have been described in detail herein, those skilled in the art will recognize that various modifications and alterations to these details may be developed in light of the overall teachings of the present disclosure. Accordingly, the particular configurations disclosed are intended solely as examples and not as limitations on the scope of the invention, which is to be given the full scope of the appended claims and any and all equivalents thereof. [Explanation of symbols]

[0068] 10 products 12 devices 14 Base Layer 16 Textured Layers 18 Ultrasonic Transducer 20 recess 22 Protrusion 24 Controller 26 Transmitter 28 Power supply (AC)

Claims

1. 1. A method for determining wear of a textured layer bonded to a base layer comprising an ultrasonic transducer, the base layer being disposed between the textured layer and the ultrasonic transducer, the textured layer comprising recesses and protrusions, the method comprising: emitting ultrasonic waves toward the recess and the protrusion by the ultrasonic transducer; receiving, by the ultrasonic transducer, ultrasonic echoes of the emitted ultrasonic waves reflected by the recesses and the protrusions of the textured layer; determining a height difference between the recess and the protrusion based on the received ultrasonic echoes; A method comprising:

2. 2. The method of claim 1, wherein determining the height difference comprises determining a time difference between echoes reflected by the recess and the protrusion, and wherein the determination of the height difference is based on the determined time difference.

3. 3. The method of claim 1, wherein the step of determining the height difference comprises determining an absorption between echoes reflected by the recess and the protrusion, and the determination of the height difference is based on the determined absorption.

4. 4. The method of claim 1, further comprising determining a frequency of a resonant peak of the textured layer bonded to the base layer, wherein the frequency of the ultrasonic waves emitted by the ultrasonic transducer is substantially equal to the determined frequency of the resonant peak.

5. 5. The method of claim 1, further comprising determining a phase shift between the ultrasonic echoes reflected by the recesses and protrusions of the textured layer.

6. 5. The method of claim 4, comprising the step of comparing the determined frequency of the resonant peak of the textured layer bonded to the base layer with expected frequencies of the resonant peak, e.g., stored in a database.

7. 7. The method of claim 1, wherein determining the height difference comprises mapping the received ultrasonic echoes to a height difference using a lookup table, database, and / or artificial intelligence model that maps the received ultrasonic echoes to a height difference between the recess and the protrusion.

8. 8. The method of claim 1, further comprising the step of communicating the determined height difference to a remote receiver, for example by at least one of Bluetooth, Bluetooth Low Energy, Zigbee, Z-Wave, NFC, RFID, and 6LoWPAN protocols.

9. The method of claim 1 , wherein the base layer comprises a metallic material.

10. The method according to claim 1 , wherein the incident angle of the emitted ultrasonic waves is perpendicular to a surface of at least one of the recess and the protrusion.

11. 11. The method according to claim 1, wherein the emitted ultrasound waves are pulsed ultrasound waves.

12. 12. The method according to any one of claims 1 to 11, preferably as an alternative to the step of determining the height difference, comprising a step of storing the frequencies of the resonant peaks of the textured layer adhered to the base layer, for example in a database.

13. 1. A device for determining wear of a textured layer affixed to a base layer, the textured layer comprising recesses and protrusions, the device comprising: an ultrasonic transducer configured to emit ultrasonic waves toward the recesses and the protrusions and to receive ultrasonic echoes of the emitted ultrasonic waves reflected by the recesses and the protrusions of the textured layer; a controller configured to determine a height difference between the recess and the protrusion based on the received ultrasonic echoes; A device comprising:

14. 14. The device of claim 13, wherein determining the height difference comprises determining a time difference between echoes reflected by the recess and the protrusion, and the determination of the height difference is based on the determined time difference.

15. 15. The device of claim 13 or 14, wherein determining the height difference comprises determining an absorption between echoes reflected by the recess and the protrusion, and the determination of the height difference is based on the determined absorption.

16. 16. The device of claim 13, wherein the controller is operably connected to the ultrasonic transducer, the controller is configured to determine a frequency of a resonant peak of the textured layer adhered to the base layer, and the controller is configured to operate the ultrasonic transducer to emit the ultrasonic waves at a frequency substantially equal to the determined frequency of the resonant peak.

17. 16. The device of claim 13, wherein the controller is further configured to determine a phase shift between the ultrasound echoes reflected by the recesses and the protrusions of the textured layer.

18. 17. The device of claim 16, wherein the controller is configured to compare the determined frequency of the resonant peak of the textured layer adhered to the base layer with expected frequencies of the resonant peak, for example stored in a database.

19. 19. The device of claim 13, wherein the determining of the height difference comprises mapping the received ultrasound echoes to a height difference using a lookup table, database, and / or artificial intelligence model that maps the received ultrasound echoes to a height difference between the recess and the protrusion.

20. 20. The device of any one of claims 13 to 19, wherein the weight of the device is between 1g and 10g.

21. 21. The device of any one of claims 13 to 20, further comprising a transmitter selected from the group consisting of a Bluetooth® transmitter, a Bluetooth Low Energy® transmitter, a Zigbee® transmitter, a Z-Wave® transmitter, an NFC® transmitter, an RFID® transmitter, and a 6LoWPAN® transmitter, wherein the transmitter is configured to communicate the determined height difference to a remote receiver.

22. 22. A device according to any one of claims 13 to 21, wherein the controller is preferably configured to store, as an alternative to determining the height difference, the frequency of a resonant peak of the textured layer adhered to the base layer, e.g. in a database.

23. 21. A product comprising the device of any one of claims 12 to 20, the product comprising a textured layer and a base layer, the textured layer being affixed to the base layer and the base layer being positioned between the textured layer and an ultrasound transducer of the device, the textured layer comprising recesses and protrusions.

24. 24. The article of manufacture of claim 23, wherein the ultrasonic transducer is embedded in the base layer.

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