Method for determining state of health of automotive glass

Abstract

The present disclosure relates to a method for determining a state of health of automotive glass. The method includes generating, by a transmitter, a guided wave to propagate over the glass. The method further includes receiving, by the sensor, the guided wave after propagation. The method further includes post-processing, by a processing unit, the received waves to determine a state of health of the glass. This constitutes an improved method for determining the state of health of the automotive glass.

Description

Technical Field

[0001] The present invention relates to the field of automotive glass, and more particularly, to a method for determining the health state of automotive glass, a system configured to perform such a method, and an automotive glass system including the automotive glass and the system configured to perform the method. Background Art

[0002] In road conditions, vehicle glass panels are subject to all kinds of vibrations, object impacts, wind loads, etc. All vibrations, impacts and other loads can be dangerous and may lead to failure of vehicle glass panels after long-term service. Documents FR2749938A1, EP3665431A1, WO2019101884A, WO2004 / 021038A1 refer to these matters.

[0003] Within this context, there remains a need for improved methods for determining the state of health of automotive glazing. Summary of the invention

[0004] Therefore, a method for determining the health state of automotive glass is provided. The method includes generating, by a transmitter, a guided wave that propagates on the glass. The method further includes receiving, by a sensor, the guided wave after propagation. The method further includes post-processing, by a processing unit, the received wave to determine the health state of the glass.

[0005] The method may include one or more of the following features:

[0006] - Guided waves propagate across the glass surface after they have been emitted by the transmitter;

[0007] - Post-processing includes detection of defects based on the received guided waves;

[0008] - the method further comprises: measuring, by the sensor, a velocity value of the guided wave; comparing, by the processing unit, the measured velocity value with a velocity value of another guided wave; determining, by the processing unit, whether there is residual stress or pressure in the glass if the comparison results in a difference between the measured velocity value and the velocity value of another guided wave;

[0009] - the transmitter is fixed to the car glass and the sensor is fixed to the car glass;

[0010] - the transmitter is fixed to the inner surface of the automobile glass, and the sensor is fixed to the inner surface of the automobile glass;

[0011] -The transmitter is a piezoelectric transmitter fixed to the car glass;

[0012] - The method further comprises: generating another guided wave by another transmitter; receiving the another guided wave by another sensor and measuring a velocity value of the another guided wave;

[0013] - the further guided wave propagates across the glass surface after it has been emitted by the further emitter;

[0014] - the further transmitter is fixed to the vehicle glass, and the further sensor is fixed to the vehicle glass;

[0015] - the further transmitter is fixed to the inner surface of the vehicle glass, and the further sensor is fixed to the inner surface of the vehicle glass;

[0016] - the other transmitter is a piezoelectric transmitter fixed to the vehicle glass;

[0017] - the transmitter and the sensor are the same transducer;

[0018] - said further transmitter and said further sensor are further identical transducers;

[0019] - the or each transducer is a piezoelectric transducer;

[0020] - the or each transducer is secured to the vehicle glass;

[0021] - the or each transducer is fixed to the inner surface of the vehicle glass;

[0022] - The transducers are positioned at positive angles to each other;

[0023] - the angle is substantially equal to 90°;

[0024] - The transducer is positioned in the top corner of the glass;

[0025] - the velocity value of the other waveguide is a reference velocity value of the reference waveguide;

[0026] - the method further comprises: measuring the temperature of the glass or the temperature near the glass by a thermal sensor, and determining whether residual stress exists comprises comparing the measured temperature with a reference temperature associated with the velocity value of the other guided wave;

[0027] - The determination of whether residual stresses exist occurs in real time;

[0028] - the method further comprises: before generating the waveguide and / or generating the further waveguide, selecting the mode of the waveguide and / or the mode of the further waveguide among non-dispersive modes; and / or

[0029] - said transmitter and said sensor are the same transducer.

[0030] - When the automotive glass is installed in a vehicle, the inner surface of the automotive glass is intended to be arranged within the vehicle interior.

[0031] The processing unit may cooperate with a series of analog and digital signal processing elements. The signal processing elements may filter and select the wave signal from the background noise. The signal processing elements may filter and select the wave signal from the background noise before post-processing of the received wave. The selection of the waveguide may include analyzing the wave dispersion of the automotive glass panel and selecting a wave mode without dispersion. The DSP unit may process the received wave signal, i.e. the received wave, because the wave signal is relatively small and sometimes complex algorithms may be preferred to extract the characteristics of the wave.

[0032] A system configured to perform a method for determining the health state of automotive glass is also provided. The system includes one or more sensors, one or more transmitters, and a processing unit. The one or more transmitters of the system are configured to generate guided waves according to the method to propagate on the glass. The one or more sensors are configured to receive the guided waves after propagation according to the method. The processing unit is configured to post-process the received waves according to the method to determine the health state of the glass. The processing unit is more generally configured to perform the steps of the method performed by the processing unit, as further discussed below. The system may further include the other transmitter, the other transmitter is configured to generate another guided wave according to the method. The system may further include the other sensor, the other sensor is configured to receive another guided wave, and measure the velocity value of the other guided wave according to the method. The system may further include the temperature sensor, the temperature sensor is configured to measure the temperature of the glass or the temperature near the glass according to the method. As discussed below for the method, each corresponding sensor and transmitter pair included by the system can form the same corresponding transducer. The system may include a series of analog and digital signal processing elements. The system may be provided as a kit comprising one or more sensors, one or more transmitters and a control unit, and optionally another sensor and transmitter and / or a temperature sensor. The kit may include notice to assemble the system. Alternatively, the system may be provided already assembled.

[0033] The or each transmitter may be secured to the vehicle glass and the or each sensor may be secured to the vehicle glass.

[0034] The or each emitter may be secured to an inner surface of the vehicle's glazing and the or each sensor may be secured to an inner surface of the vehicle's glazing.

[0035] An automotive glass system is also provided, the automotive glass system comprising automotive glass and a system configured to perform the method. The automotive glass system may be provided as a kit comprising the system configured to perform the method and unassembled glass, optionally with instructions for assembling the system configured to perform the method with the glass. Alternatively, the automotive glass system may be provided as a single device formed by the glass and the system configured to perform the method assembled to the glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Non-limiting examples will now be described with reference to the accompanying drawings, in which:

[0037] -[ Figure 1 ],[ Figure 1 ] shows an example of the method. DETAILED DESCRIPTION

[0038] A method for determining a health state of automotive glass is provided. The method includes generating a guided wave by a transmitter to propagate on the glass. The method further includes receiving the guided wave after propagation by a sensor. The method further includes post-processing the received wave by a processing unit to determine a health state of the glass.

[0039] Such a method forms an improved solution for determining the state of health of automotive glazing.The method enables an improved determination of the state of health of automotive glazing in an efficient and simplified manner.

[0040] This is achieved by a method comprising generating guided waves by a transmitter to propagate on the glass and receiving the guided waves by a sensor after propagation. Guided waves are known to be used for inspection and detection of faults, such as cracks, fissures, holes or voids, and fatigue of materials (e.g., residual stress), but their use for automotive glass inspection and defect or fatigue detection has not been studied. However, the inventors have found that the planar and thin structure of automotive glass can support guided waves, so that one or more guided waves can be efficiently used to inspect automotive glass, so as to determine the health state of the glass, for example, by detecting and evaluating defects and / or measuring glass residual stress. Since one guided wave transmitter (e.g., transducer) can cover a large area, using such waves for such tasks provides improved efficiency and simplicity in the determination of the health state of the wave (as, for example, compared to the use of body waves). Thus, using guided waves, as the method does, saves electronics, wave transmitters, wave sensors and transducers. The use of guided waves also enables the determination of the health state of the automotive glass to be non-invasive. In addition, by using guided waves, the method goes one step further than vibration detection by also determining the health state of the glass.

[0041] Methods used to determine the health of automotive glass include:

[0042] - A guided wave is generated by a transmitter to propagate on the glass;

[0043] - receiving the guided waves after propagation by a sensor; and

[0044] - The received waves are post-processed by a processing unit to determine the health state of the glass.

[0045] The method determines the state of health of automotive glass. The state of health of automotive glass refers to the condition or state of automotive glass at a specific point or stage during its life. Therefore, determining the state of health of automotive glass includes determining any parameter or event related to the state of automotive glass, such as, for example, detecting defects on the glass or determining residual stress of the glass. Automotive glass is any glass panel of any vehicle (e.g., a car), such as, for example, a windshield, a sunroof, a rear light, or a side light. The glass can be, for example, a layer of tempered glass or a laminated glass.

[0046] The method uses a transmitter and a sensor, i.e., at least one transmitter and at least one sensor. The transmitter (i.e., each transmitter used in the method) is an electronic device for sending out or emitting waves. In the present case, the transmitter is configured to emit guided waves, and such waves are emitted during the method. The transmitter may, for example, emit ultrasonic guided waves. The transmitter may, for example, include piezoelectric materials, or may be of electromagnetic design. The sensor (i.e., each sensor used in the method) is a device for receiving and measuring waves. Each sensor herein is configured to receive and measure guided waves. The sensor may be configured to measure ultrasonic guided waves. The method uses at least one corresponding pair consisting of a corresponding transmitter and a corresponding sensor. The method may use one or more such pairs, i.e., one or more transmitters with one or more sensors, wherein each transmitter emits a corresponding guided wave, and each sensor receives the emitted guided wave. Each sensor and transmitter in each pair may form a single identical transducer that works as both a transmitter and a sensor, as discussed further below. The transducer used by the method may be positioned on the glass as a transducer array. Each transmitter, sensor and transducer herein can be fixed to the glass or to the body of the automobile vehicle (e.g., a car frame) by any known fixing technique. Each transmitter, sensor and transducer can be positioned on face 1 or face 2 of the automobile glass, which is, for example, tempered glass (face 1 is the outer surface of the glass and face 2 is the inner surface of the glass). For example, each transmitter, sensor and transducer is fixed on face 2. Generally, for tempered glass, there are only two faces, face 1 and face 2. Alternatively, each transmitter, sensor and transducer can be positioned on face 4 of the automobile glass, which is, for example, laminated glass. For laminated glass (most of the windshield), there are three layers (glass-PVB-glass): face 1 is the outer surface of the first glass, face 2 is the inner surface of the first glass and the first surface of the PVB layer, face 3 is the second surface of the PVB and the first surface of the second glass, and face 4 is the second (inner) surface of the second glass.

[0047] The guided waves generated by the transmitter (i.e., each guided wave generated by the corresponding transmitter) are waves whose energy is concentrated near or between boundaries. The guided waves may be, for example, Lamb waves (symmetric / asymmetric wave modes, A0 / S0, ​​A1 / S1, etc.), Rayleigh waves, shear horizontal waves (SHO, SH1, etc.), or surface acoustic waves. The guided waves may be, for example, ultrasonic guided waves. The propagation of the guided waves on the glass refers to the journey that the waves make across the glass surface after they have been emitted by the transmitter. Therefore, each transmitter is configured to emit the guided waves so that the guided waves travel on the glass.

[0048] The method further includes post-processing the waves received by the sensors (i.e., each wave received by each sensor) to determine the health of the glass. Post-processing can include applying any method to process (one or more) received guided waves to determine the health of the glass. Post-processing will be discussed further below.

[0049] The post-processing is performed by a processing unit. The processing unit may also be referred to as a "data processing module" or a "data processing unit". The processing unit may be a processing unit of any suitable computer system, such as a general-purpose computer or a microcontroller. The processing unit may be composed of one or more processors of such a system. The processing unit may be composed of one or more CPUs (central processing units) of the system. The processing unit may be coupled to a memory having a computer program including instructions recorded thereon, and when the program is executed, the instructions cause the processing unit to perform post-processing of the received waves. The processing unit may be connected to each transmitter and sensor used by the method in any suitable manner (e.g., by a wired connection), so that the processing unit may perform post-processing when receiving (one or more) guided waves measured by (one or more) sensors. Alternatively, (one or more) received waves may be transmitted, for example, by means of a wireless connection (e.g., by means of a microcontroller or another suitable processing unit connected to (one or more) transmitters and (one or more) sensors and to a wireless connection device such as a 4G / 5G chip) to an external computer system including a processing unit that performs post-processing.

[0050] The computer program may include instructions executable by a computer, the instructions including components for causing the above processing unit to perform post-processing. The program may be recordable on any data storage medium, including a memory of a processing unit. The program may be implemented, for example, in a digital electronic circuit, or in computer hardware, firmware, software, or a combination thereof. The program may be implemented as a device, such as a product tangibly embodied in a machine-readable storage device for execution by a programmable processor. The post-processing step may be performed by a programmable processor that executes the instruction program to perform the function of post-processing by operating on input data and generating output. Therefore, the processor may be programmable and coupled to receive data and instructions from a data storage system, at least one input device, and at least one output device, and to transmit data and instructions to them. If desired, the application may be implemented in a high-level procedural or object-oriented programming language, or in an assembly or machine language. In any case, the language may be a compiled or interpreted language. The program may be a complete installer or updater. The application on the system in any case causes instructions for performing post-processing. Alternatively, the computer program may be stored on a server in a cloud computing environment and executed thereon, and the server communicates with one or more clients across a network. In such a case, the processing unit executes instructions included by the program, thereby causing post-processing to be performed on the cloud computing environment.

[0051] Post-processing may include detecting defects based on the received guided waves. Defects may be any irregularities present along the automotive glass. Defects may, for example, be present in one or more cracks, one or more cracks, one or more holes, and / or one or more voids in the glass. To this end, post-processing may include applying any suitable method or methodology for detecting such defects based on the received guided waves. Such methods or methodologies may be found, for example, in U.S. Pat. No. 2,280,226, entitled “Flaw Detecting Device and Measuring Instrument,” dated April 21, 1942, which is incorporated herein by reference.

[0052] Examples of methods for detecting defects are now briefly discussed.

[0053] In this example, there may be one or more pairs consisting of a transmitter that emits a guided wave and a sensor that receives the wave, each pair consisting of, for example, a transducer (e.g., an ultrasonic transducer). Thus, one or more guided waves are generated and received, the guided waves comprising one or more Lamb waves (e.g., symmetrical / asymmetrical wave modes, A0 / S0, ​​A1 / S1), one or more Rayleigh waves, one or more shear horizontal waves (SH0, SH1), and / or one or more shear vertical waves. Depending on the layout and number of the sensor and transmitter (or transducer) pairs, the method may use a pulse echo method or a send-and-receive method for inspection, where appropriate. The mode of each guided wave emitted may be selected from a non-dispersive or minimum dispersion mode in order to avoid a dispersion mode. In the implementation of the detection method, the frequency Rayleigh-Lamb equation governing the plate guided wave is as follows:

[0054] symmetry:

[0055]

[0056] Asymmetric:

[0057]

[0058] where p and q are denoted by:

[0059]

[0060] The group velocity of Lamb waves can be expressed as follows:

[0061]

[0062] where the variables q and p are defined in the equation, h is half the thickness (i.e. d / 2), k is the wave number, ω is the angular frequency, and c L is the longitudinal wave velocity, c T is the shear wave velocity, c g is the group velocity, f is the frequency, c p is the phase velocity, and d is the thickness of the structure for guiding the waves.

[0063] In this implementation, the resolution of defects is governed by the frequency and wave mode. Generally, the higher the frequency, the better the resolution. In the implementation, a transducer array is used in order to improve the spatial resolution or localization of defects.

[0064] The method may additionally or alternatively include determining the residual stress or pressure of the glass using a sensor, a transmitter and a processing unit. To this end, the method includes measuring the velocity value of the waveguide by the sensor, and comparing the measured velocity value with the velocity value of another waveguide by the processing unit. Then, the method includes, if the comparison causes a difference or inconsistency between the measured velocity value and the velocity value of another waveguide, determining by the processing unit whether there is residual stress or pressure of the glass. This can mean that the method can evaluate the inconsistency between the two velocity values ​​(for example, the difference between the two values ​​can be evaluated to exceed a predefined threshold value), and the inconsistency is related to the presence of residual stress or pressure. The determination can be performed by comparing the measured velocity with the velocity of another waveguide and correlating the presence or absence of residual stress or pressure with any suitable method of the comparison. The expression of the equation governing the waveguide discussed previously can be used to calculate the velocity of any waveguide herein.

[0065] In order to determine the residual stress or pressure, the method can use another transmitter and another sensor, which can be the same transducer (in this case, the sensor and the transmitter also form the same transducer). In this case, the method can apply a pitch-catch method. The other transmitter generates another guided wave, and the other sensor receives the other guided wave. The other sensor measures the velocity value of the other guided wave. In other words, in this case, two guided waves are emitted and received (for example, by two transducers as previously discussed), and then the processing unit determines whether there is residual stress of the glass or pressure along the glass by comparing the speed of the two waves and determining whether the comparison causes a difference / inconsistency between the measured velocity value and the velocity value of the other guided wave. According to the basic principle of waves in solids, if there is residual stress in the inspection plate, the velocities of guided waves with different directions may be different. Therefore, the transducers can be positioned at a positive angle to each other (that is, positioned so that the corresponding waves they emit are emitted so as to form this positive angle). The transducers may be positioned separately, for example, one at the left corner of the glass (e.g., the top corner or the bottom corner) and the other at the right corner of the glass (e.g., the top corner or the bottom corner). According to another example, two transducers may be positioned in the top corners of the glass (i.e., one in each corner). This results in different propagation directions of the guided waves (e.g., Lamb waves or Rayleigh waves, whose governing equations have been discussed previously) generated by the two transmitters. The angle between the transducers may be equal to or substantially equal to 90°.

[0066] Alternatively, instead of the value of the measured guided wave, the value of the other guided wave may be a reference value of a reference guided wave. In this case, the method may use a single sensor and a single transmitter, which may form a single identical transducer. As previously discussed, the sensor measures the velocity value of the guided wave emitted by the transmitter, and the processing unit compares the measured velocity value with the reference velocity value. If the comparison results in a difference (or inconsistency) between the measured velocity value and the reference velocity value, the processing unit then determines whether there is residual stress of the glass or pressure along the glass. In this case, the method may use a pulse echo method, since only one sensor-transmitter pair (e.g., only one transducer) may be used.

[0067] In this case, the temperature of the glass or the vicinity of the glass can be an additional variable that can be used to determine whether there is residual stress. In fact, the reference value can be related to the existence of residual stress or pressure for a specific temperature or a specific temperature range near the glass or the glass. In contrast, in the previous case of two measured velocities of two measured waves, temperature is not a variable. Therefore, the method may further include measuring the temperature of the glass or the vicinity of the glass (that is, the temperature of the glass or the temperature of the air near the glass) by a thermal sensor. Then, determining whether there is residual stress includes determining whether there is residual stress by comparing the measured temperature with a reference temperature associated with the velocity value of another waveguide. In other words, the known stress and temperature of the glass corresponding to the reference velocity value can be used as a reference value to relate the measured velocity value and the measured temperature to the residual stress or pressure of the glass in the case where the temperature and velocity are measured by the method. For example, the velocity of glass without stress can be used as a benchmark to derive stressed glass.

[0068] In any case, whether it is the case of using another measured velocity value or the case of a reference velocity value (both of which have been discussed), the difference in the velocity (also called "group velocity") of the two guided waves can be well correlated with the residual stress of the glass. The stress gauge can be implemented by using a standard glass panel with known stress as a reference or calibrating the strain gauge. By comparing the two stresses with the original state, a safety threshold can be determined (or by directly comparing the guided wave velocity with the guided wave velocity of the reference glass, because the threshold can be set by the difference in velocity between the two). The safety threshold can be expressed as part of the health state of the glass. The safety threshold can be expressed as part of the health state of the glass. That is, if the method includes obtaining the initial state of the glass, a sensor such as a temperature sensor may be required because the velocity may also be affected by the temperature of the structure. However, if the method includes taking the two transmitters / sensors at a certain angle, there is no need to use such a sensor. The threshold can be set directly using the difference in the velocity of the waves in the two directions. In some cases, the health state of the glass can be beneficial when residual stresses in the material structure are to be avoided. When the internal stress reaches a certain value that the material can support, the stress energy may be released and thereby cause failure of the structure (eg, fractures, cracks, and / or fissures).

[0069] Advantageously and unlike conventional strain gauges, the stress that can be measured by generating, receiving and post-processing guided waves can result in an overall or average value for the glass, rather than stress at a specific location or on a surface.

[0070] The residual stress of the glass panel can be monitored in real time under road conditions (i.e., the determination of whether residual stress exists can occur in real time). As previously discussed, depending on, for example, the preferred layout of the sensor and the transmitter, and / or the total desired number of sensors and transmitters, the method can be applied according to a pulse echo method or a send-receive method. For example, a pulse echo method using one sensor and transmitter or one transducer can be preferred to minimize the use of hardware. The pulse echo method also uses one sensor as a transmitter (e.g., an ultrasonic transmitter) and a receiver (e.g., an ultrasonic receiver). In order to save hardware, the pulse echo method can also be preferably used for materials and / or structures with less damping. Examples of such materials / structures can include tempered glass, single-layer glass, and / or laminated glass with less damping PVB or standard PVB. The send-receive method uses a transmitter (e.g., an ultrasonic transmitter) and another separate receiver (e.g., an ultrasonic receiver) to obtain a signal, i.e., waveguide. The send-receive method can be preferably used for large damping materials and / or structures. In other words, for high damping materials such as laminated acoustic PVB, a pitch-catch approach should be preferred to ensure sufficient signal.

[0071] As previously discussed, the method may include, prior to generating the guided wave and / or generating the further guided wave (or any generated guided wave herein), selecting the mode of the guided wave and / or the mode of the further guided wave among non-dispersive modes. For example, Rayleigh waves may be preferred for surfaces with a maximum thickness of 1 mm.

[0072] The determined health state may indicate whether the automotive glass is in a functional condition. Additionally or alternatively, the health state may be evaluated to make a prediction about the condition of the automotive glass in the future. Such a prediction may be a short-term prediction. Alternatively, such a prediction may be a long-term prediction. Alternatively, such a prediction may determine the remaining life of the automotive glass. The method may include evaluating such an indication or making such a prediction based on the determined health state.

[0073] The processing unit can cooperate with other electronic hardware, such as, for example, a DSP (digital signal processor) board, an FPGA (field programmable gate array), an amplifier and / or a preamplifier. The processing unit can cooperate with a series of analog and digital signal processing elements. The signal processing element can filter and select wave signals from background noise. Before the received wave is post-processed, the signal processing element can filter and select wave signals from background noise. The selection of waveguides can include analyzing the wave dispersion of the automobile glass panel and selecting a wave mode without dispersion. The DSP unit can process the received wave signal, i.e. the received wave, because the wave signal is relatively small, and sometimes a complex algorithm may be preferred to extract the characteristics of the wave. All electronic hardware herein can, for example, be installed on the dashboard of the vehicle, or near the other position of the desired glass panel of the vehicle (for example, a suitable pillar of the vehicle, such as so-called "pillar A"). The screen of the dashboard can display the health status of the automobile glass and / or any other determined value related to the health status. Additionally or alternatively, a 4G or 5G chip or a Bluetooth device or any other suitable communication component can transmit the health status of the vehicle glass and / or any other determined values ​​related to the health status to an external Internet source.

[0074] [ Figure 1] relates to an example of a method and system in which transducers 101, 102 are positioned on an automotive glass in the form of a glass panel, substantially at a 90° angle to each other (i.e., the directions of the waves they emit substantially form a 90° angle). The transducers are positioned in the top corners of the glass panel. According to one configuration, the transducers 101, 102, each of which includes a transmitter and a sensor, generate guided waves 104, 105, which propagate along the glass according to trajectories 106, 107. The propagated waves 104, 105 are reflected back to the transducers 101, 102 and are received by the transducers 101, 102. The transducers 101, 102 measure the velocity values ​​of the received waves 104, 105. Then, a processing unit (not shown) performs post-processing on the received waves to determine the health state of the glass. The processing unit compares the measured velocity value of one of the two waveguides 104 with the velocity value of the other of the two waveguides 105. If the comparison results in a difference / inconsistency between the measured velocity value of the first guided wave 104 and the velocity value of the second guided wave 105, the processing unit then determines if there is residual stress or pressure along the glass.

[0075] According to another configuration of the example, a temperature sensor 103 placed on the automotive glass and between two transducers 101, 102 measures the temperature on or near the glass. One of the transducers 101, 102 generates a guided wave 104, 105, which propagates along the glass according to trajectories 106, 107. The propagated waves 104, 105 are reflected back to the transducers 101, 102 and received by the transducers 101, 102. The transducers 101, 102 measure the velocity values ​​of the received waves 104, 105. Then, a processing unit (not shown) post-processes the received waves to determine the health state of the glass. The processing unit determines whether there is residual stress by comparing the measured temperature with a reference temperature associated with the velocity value of the other guided wave, which is a reference velocity value of the reference guided wave.

Claims

1. A method for determining the health status of automotive glass, the method include: - generating a guided wave (104) by a transmitter (102) to propagate on the glass; - receiving the guided waves after propagation by a sensor (102); and - The received waves are post-processed by a processing unit to determine the health state of the glass.

2. The method of claim 1, wherein post-processing comprises detecting defects based on the received guided waves.

3. The method according to claim 1 or 2, wherein the transmitter (102) is fixed to the vehicle glass and the sensor (102) is fixed to the vehicle glass.

4. The method of claim 3, wherein the transmitter (102) is fixed to an inner surface of the vehicle glass and the sensor (102) is fixed to an inner surface of the vehicle glass.

5. The method according to any one of the preceding claims, wherein the method further comprises include: - measuring the velocity value of the guided wave (104) by the sensor (102); - the processing unit compares the measured velocity value with the velocity value of another waveguide (105); If the comparison results in a difference between the velocity value measured and the velocity value of another guided wave, it is determined by the processing unit whether there are residual stresses or pressures in the glass.

6. The method according to claim 5, wherein the method further comprises include: - generating another guided wave (105) by another transmitter (101); - receiving another guided wave by another sensor (101) and measuring a velocity value of the other guided wave (105).

7. The method according to claim 6, wherein the further transmitter (101) is fixed to the vehicle glass and the further sensor (101) is fixed to the vehicle glass.

8. The method according to claim 7, wherein the further transmitter (101) is fixed to the inner surface of the vehicle glass and the further sensor (101) is fixed to the inner surface of the vehicle glass.

9. The method according to any one of claims 6 to 8, wherein the transmitter and the sensor are one and the same transducer (102), and the further transmitter and the further sensor are another one and the same transducer (101).

10. The method of claim 9, wherein the transducers (101, 102) are positioned at a positive angle to each other. The method of claim 10 , wherein the angle is substantially equal to 90°.

12. The method of claim 11, wherein the transducers (101, 102) are positioned in corners of the glass.

13. The method according to any one of claims 5 to 12, wherein the velocity value of the further waveguide (105) is a reference velocity value of the reference waveguide.

14. The method according to claim 13, wherein the method further comprises include: - measuring the temperature of the glass or the temperature near the glass by means of a thermal sensor (103), Determining whether residual stress is present includes comparing the measured temperature to a reference temperature associated with a velocity value of another guided wave (105).

15. A method according to any one of claims 5 to 14, wherein determining whether residual stress is present occurs in real time.

16. The method according to any one of claims 1 to 15, wherein the method further comprises, before generating the waveguide (104) and / or generating the other waveguide (105), selecting a mode of the waveguide (104) and / or the other waveguide (105) among non-dispersive modes.

17. The method according to any one of claims 1 to 16, wherein the transmitter and the sensor are the same transducer (101, 102).

18. A system comprising one or more sensors (101, 102), one or more transmitters (101, 102), and a processing unit, the system being configured to perform the method of any one of claims 1 to 17.

19. A system according to claim 18, wherein the or each transmitter (101, 102) is fixed to the vehicle glass and the or each sensor (101, 102) is fixed to the vehicle glass.

20. A system according to claim 19, wherein the or each emitter (101, 102) is fixed to the inner surface of the vehicle glass and the or each sensor (101, 102) is fixed to the inner surface of the vehicle glass.

21. An automotive glass system comprising automotive glass and a system according to any one of claims 18 to 20.

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