EP4725620A1 - System for ultrasonic cleaning - Google Patents

System for ultrasonic cleaning

Info

Publication number
EP4725620A1
EP4725620A1 EP24205244.7A EP24205244A EP4725620A1 EP 4725620 A1 EP4725620 A1 EP 4725620A1 EP 24205244 A EP24205244 A EP 24205244A EP 4725620 A1 EP4725620 A1 EP 4725620A1
Authority
EP
European Patent Office
Prior art keywords
ultrasonic waves
transducers
contamination
control unit
liquid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24205244.7A
Other languages
German (de)
French (fr)
Inventor
Mincheol Shin
Harry Page
Joshua Keaton Odling-Thomas
Steffen Walter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Echovista Ultrasound Surface Cleaning Ltd
Original Assignee
Echovista Ultrasound Surface Cleaning Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Echovista Ultrasound Surface Cleaning Ltd filed Critical Echovista Ultrasound Surface Cleaning Ltd
Priority to EP24205244.7A priority Critical patent/EP4725620A1/en
Priority to PCT/EP2025/077766 priority patent/WO2026077741A1/en
Publication of EP4725620A1 publication Critical patent/EP4725620A1/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
    • B08B7/02—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by distortion, beating, or vibration of the surface to be cleaned
    • B08B7/026—Using sound waves
    • B08B7/028—Using ultrasounds

Landscapes

  • Cleaning By Liquid Or Steam (AREA)

Abstract

Described is a system for ultrasonic cleaning of a surface, a corresponding method, and a use of the system for cleaning a surface. The method for clearing a contamination from a surface is comprising: generating first ultrasonic waves; coupling the first ultrasonic waves to the surface; receiving at least some of the first ultrasonic waves; detecting a change in one or more characteristics of a plurality of characteristics of the at least some of the first ultrasonic waves in the; determining a cleaning action for the surface from a set of predefined cleaning actions based on the detected change in the one or more characteristics; generating second ultrasonic waves; and coupling the second ultrasonic waves to the surface in accordance with the determined cleaning action.

Description

    TECHNICAL FIELD
  • The present invention relates to a system for ultrasonic cleaning of a surface, a corresponding method, and a use of the system for cleaning a surface.
    • BACKGROUND
  • Surfaces such as glass plates in windows, protective covers of optical viewing equipment, mirrors and others are typically subject to contamination, such as by rain, mud or other media. Such contamination may impair the visibility through such a surface or may be harmful to the surface or a coating applied to the surface, such that cleaning of the surface becomes necessary. Mechanical means of cleaning may themselves be harmful to the surface or a coating. Wipers or cloths may themselves be designed to gently contact the surface. However, the content of the contamination, such as grains of sand or other particles may be harmful in such scenarios independent of the design of the mechanical means for cleaning the surface. Additionally, mechanical surface cleaning means themselves may occlude visibility through a glass surface during cleaning of the surface. In the state of the art, ultrasonic cleaning methods for surfaces have been described, in which ultrasonic waves are used to clean surfaces instead of mechanical means. Furthermore, in order to reduce the stress on the components of the cleaning systems and the surface to be cleaned, detection methods have been described, wherein the cleaning is only carried out when a contamination is sensed. However, ultrasonic cleaning of surfaces is not as reliable as mechanical means in removing contamination completely.
    • SUMMARY
  • It is thus an object of the present invention to provide a system which is capable of cleaning surfaces more reliably.
  • This object is achieved by a system as defined by independent claim 1, by a method as defined by claim 11 and by the use of a system of claims 1 to 10 according to claim 15.
  • The inventors have realized that the reliability of ultrasonic cleaning of a surface depends on the contamination present on the surface. While the detection of the presence of a contamination allows for efficient use of the cleaning system (e.g. no power is wasted on operating the system when no contamination is present), a general mode of cleaning does not reliably remove contaminations. The inventors have, thus, realised that in order to increase the reliability of ultrasonic cleaning, tailored cleaning actions are beneficial, whereby in a system able to detect the presence of a contamination, different detections lead to different cleaning actions of the system, thereby increasing the reliability and efficiency of cleaning according to the contamination.
  • According to a general aspect of the invention, a system for clearing a contamination from a surface is provided, the system comprising: one or more ultrasound transducers configured to couple ultrasonic waves to the surface; at least one generator configured to generate a drive signal to drive the one or more transducers; a receiver configured to receive at least some of the ultrasonic waves coupled to the surface; and a control unit; wherein the control unit is configured to: cause the at least one generator to generate a first drive signal to drive the one or more transducers; cause at least one of the one or more transducers to produce first ultrasonic waves in accordance with the first drive signal to couple the first ultrasonic waves to the surface; detect a change in one or more characteristics of a plurality of characteristics of at least some of the first ultrasonic waves received by the receiver; determine a cleaning action for the surface from a set of predefined cleaning actions based on the detected change in the one or more characteristics; cause the at least one generator to generate a second drive signal in accordance with the determined cleaning action to drive at least a portion of the one or more transducers; and cause the portion of the one or more transducers to produce second ultrasonic waves in accordance with the second drive signal to couple the second ultrasonic waves to the surface.
  • By detecting change in one or more characteristics of a plurality of characteristics of the first ultrasonic waves in the received at least some of the first ultrasonic waves, a cleaning action corresponding to the detected change may be determined and performed. Thus, the cleaning of the surface may be suited to the specific detected change, allowing for more reliable and efficient cleaning.
  • In an aspect of the invention, the control unit is further configured to infer a type of the contamination on the surface from a predefined set of types of contaminations from the detected change in the one or more characteristics of the at least some of the first ultrasonic waves and wherein the determined cleaning action corresponds to the inferred type of the contamination wherein the predefined set of types of contaminations comprises at least one of ice fog/condensation mud, dust, biological matter (e.g., protein) and liquid (e.g. droplets). In another aspect of the invention, the predefined set of cleaning actions may comprise at least one cleaning action for every type of contamination. The predefined set of cleaning actions may also comprise one cleaning action for every detected change in the one or more characteristics in the predefined set of detected changes.
  • By inferring the type of the contamination, different detected changes in one or more characteristics of the at least some of the received first ultrasonic waves may be grouped together. Thus, cleaning actions which are applicable to more than one detected change, can be efficiently mapped to all relevant detected changes, allowing for better categorization of detected changes and applicable cleaning actions allowing for more efficient cleaning of the surface. Furthermore, the predefined set of cleaning actions can be better tailored to the types of contamination. Moreover, in systems in which a user interacts with the system, representation of a detected change as a type of the contamination is helpful, since users are typically unable to properly distinguish, compare or otherwise usefully analyse changes in ultrasonic waves reliably or understand in detail the content of such changes. The above-mentioned types of contamination represent the most common types of contamination, such that the inclusion of any one of these allows for more reliable and complete cleaning of the surface.
  • The characteristics may be characteristics that define the ultrasonic wave, such as frequency, amplitude, and/or phase. In an aspect of the invention, the control unit is configured to detect the change in the one or more characteristics of the at least some of the first ultrasonic waves by comparing the at least some of the first ultrasonic waves to a base level signal, and/or wherein the detected change is a change in the waveform or frequency characteristics of the at least some of the first ultrasonic waves, wherein, preferably, the detected change is at least one of the power level, the frequency spectrum and the amplitude of the ultrasonic detection waves.
  • The detection of the change in one or more characteristics of the received at least some of the first ultrasonic waves may be more reliable when done by comparison with a base level signal. Factors, such as the dimensions of the surface, the material of the surface, the placement of the transducers and the receiver relative to one another and other optional objects may all influence the first ultrasonic waves while travelling from one of the transducers to the receiver. Thus, in order to more reliably detect changes in one or more characteristics of the received at least some of the first ultrasonic waves, the comparison with such a base level is beneficial. The ultrasonic waves coupled to the surface, travel through the surface and are subject to several effects according to the properties of the surface, such as the surface material, dimensions etc. For example, ultrasonic waves are subject to attenuation due to energy dissipation. For example, the first ultrasonic waves may be partially coupled into a contamination present on the surface at the boundary between the surface and the contamination. Different media, however, also have different dissipative properties, such that the attenuation may be stronger or weaker than in the material of the surface or may be more or less pronounced at different frequencies, such that a detected change in a characteristic of the received at least some of the first ultrasonic detection waves allows the control unit to determine the appropriate corresponding cleaning action. The detected changes may vary depending on the parameters of the system, environmental conditions and parameters of the surface. For example, the dimensions of the surface, the material of the surface, the ambient temperature, the distance between the transducer(s) and the receiver etc. may all influence the ultrasonic waves in the surface. Thus, in another aspect of the invention, the system may be calibrated to the surface and conditions in which it is applied. This may also entail calibrating the base level signal accordingly, e.g. by recording such a base level signal in the conditions to which the system is applied.
  • In an aspect of the invention, the one or more transducers comprise at least two transducers, and wherein one of the at least two transducers functions as the receiver.
  • By comprising at least two transducers, the system is capable of more thoroughly cleaning the surface since a large number of combinations of second ultrasonic waves may be applied according to the cleaning actions determined by the control unit. Furthermore, due to the attenuation of the waves in the surface and contaminations and the general inverse square law, the use of at least two transducers reduces the energy consumption of the system at equal performance. When one of the at least two transducers functions as the receiver for the first ultrasonic waves, a further component of the system is not required such that the system becomes less complex, requires fewer components, and can, thus, be incorporated into other systems or environments more easily.
  • In an aspect of the invention, the control unit is configured to assess, whether the detected change in the one or more characteristics crosses a threshold value, such that the cleaning action to be performed is only determined and/or performed when the detected change in the one or more characteristics crosses the threshold value. The system preferably further comprises: a transceiver configured to detect environmental conditions, wherein the detectable environmental conditions include at least one of temperature, humidity and air flow, wherein the control unit is configured to receive information conveying the detected environmental conditions and determine the cleaning action based also on the received information, and wherein, preferably, the control unit is configured to adapt the threshold value to the environmental conditions based on the received information. The environmental conditions may be the conditions prevailing in the vicinity of the surface and/or the transducers.
  • By making the determination and/or performance of the cleaning action conditional on whether the detected change crosses a threshold value, unnecessary operation of the system to clean the surface is mitigated. For example, when the amount of contamination on the surface is negligible it is inefficient for the system to perform the cleaning action, since this may unfeasibly increase the frequency of performing said action. Furthermore, the use of a threshold value allows the system to be more robust to outliers in detected changes in the one or more characteristics of the received at least some of the first ultrasonic waves, which may be caused by factors external to the system. It is further beneficial for the control unit to be configured to infer the type of the contamination based also on the received information conveying the environmental conditions detected by the transceiver. For example, when the environmental temperature is particularly low, e.g. -20°C, this may be an indicator that contaminations which are similar to water may be snow, ice or sleet. In another aspect of the invention the control unit is thus configured to base the determination of the cleaning action corresponding to the detected change in one or more characteristics of the received at least some of the first ultrasonic waves and/or the inferring of the type of the contamination also on the received information conveying the environmental conditions. Environmental conditions such as the temperature, humidity or air flow may cause a change in the characteristics of the received at least some of the ultrasonic waves. Dispersion properties typically depend on the temperature, such that the threshold value may be inadvertently crossed even though no contamination or only a negligible amount of contamination is present. Furthermore, the ambient humidity may change the electrical properties of components of the system, such that the threshold values may also be crossed due to artefacts in the electrical communications between components. In order to prevent misdetections and unnecessary determination/performance of cleaning actions, causing inefficient use of resources, it is beneficial for the control unit to be able to adapt the threshold values accordingly.
  • In an aspect of the invention, the system further comprises: a liquid supply apparatus configured to supply liquid, preferably water, to the surface; wherein the control unit is configured to cause the liquid supply apparatus to supply liquid to the surface in accordance with the determined cleaning action, preferably wherein the transducers are configured to couple ultrasonic waves to the liquid through the surface and/or directly, and/or wherein the control unit is configured to cause the liquid supply apparatus to supply liquid in accordance with the detected type of contamination.
  • For some contaminations it can be useful for liquid to be supplied to the surface. The supplied liquid may dissolve contaminations such that cleaning of the surface is facilitated. The transducers may couple ultrasonic waves to the liquid directly, when the liquid is in contact with the transducers. The transducers may also couple ultrasonic waves to the liquid indirectly through the surface to which the liquid has been applied. The liquid may surround the contamination after being supplied to the surface. Thus, the area of contact between the contamination and a medium carrying the ultrasonic waves (e.g. the surface and/or the liquid) is increased allowing for an enhanced determination of the cleaning action and cleaning of the surface. For example, when rain or other liquid is detected on the surface, the usefulness of liquid in the cleaning action is low. Thus, the control unit may not cause the liquid supply apparatus to supply liquid to the surface in such a scenario, when the cleaning action does not entail such a supply of liquid. However, when in an example the detected contamination type is mud, biological matter (e.g., protein), dust or any further such type, the supply of liquid can increase the effectiveness of the second ultrasonic waves. Furthermore, the liquid can dissolve the contamination at least in part. Additionally, the liquid supplied to the surface may be caused by the cleaning action to be propelled to the edge of the surface and may in this manner collide and loosen the contamination. Thus, a more reliable cleaning may be achieved.
  • In an aspect of the invention, the system comprises a power amplifier configured to amplify the power of the generated first and/or second drive signals; wherein the power amplifier is configured to be operable in at least two different modes, each mode corresponding to a different amount of amplification; wherein the control unit is configured to cause at least some of the portion of the one or more transducers to produce ultrasonic waves driven by differently amplified drive signals in accordance with the determined cleaning action.
  • By being configured to adjust the power level of the ultrasonic waves produced by the transducers and coupled to the surface, the system is enabled to perform cleaning actions corresponding to different types of contaminations, which may have different properties. In an aspect of the invention, the power level may be adjusted such that the transducers may at least be able to operate at a base power level and a high power level. The high power level may correspond to approximately twice the power of the base power level. In a further aspect the power level may be adjusted such that the transducers may further be able to operate at a low power level. The low power level may, for example, correspond to approximately one fifth of the base power level. In another aspect, the power level may be adjusted such that the transducers may further be able to operate at further power levels between the low and the high power level and/or below the low power level and/or above the high power level. Thus, different contaminations may be cleaned in a manner corresponding to the contamination. For example, denser contaminations may require higher power levels for propulsion than less dense contaminations. In another example, heat may be generated in a contamination by applying a high power level. In yet another example, small droplets (liquid), as for example are present in condensation or fog, may be reliably cleaned using low power levels, thus reducing the energy consumption of the system.
  • In an aspect of the invention, the at least one generator comprises a pulse generator, such that the at least one generator is configured to be able to produce pulsed drive signals, and wherein the control unit is configured to adjust the pulse frequency and/or duration, preferably wherein the control unit is configured to cause synchronously and/or asynchronously pulsed ultrasonic waves to be produced by different transducers of the portion of one or more transducers. In yet another aspect, the control unit is configured to adjust the pulse frequency and/or duration according to the determined cleaning action for one or more transducers of the portion of the one or more transducers.
  • Pulsed second ultrasonic waves allow for quicker propulsion of liquid (e.g, droplets) across the surface. Individual pulsing of the transducers allows for complex and efficient cleaning actions. Additionally, the stress induced in the surface by the ultrasonic waves may be reduced, which is beneficial for the longevity and stability of the surface. Furthermore, the energy consumption of the system may be reduced when pulsed ultrasonic waves are produced. The complexity of the superimposed (first/second) ultrasonic waves in the surface may be adapted to the needs of the system in detecting changes in the characteristics of the received at least some of the first ultrasonic waves or in performing the determined cleaning actions by allowing synchronous and asynchronous pulsing sequences for different transducers. For example, asynchronous pulsing of two opposite transducers during synchronous, non-pulsed activation of a third transducer allows particularly efficient removal of liquid liquid (e.g. droplets) from the surface.
  • In an aspect of the invention, the control unit is configured to cause the at least one generator to modulate the first and/or second drive signal in accordance with the determined cleaning action, wherein at least one of the amplitude, the frequency and the phase shift of the first and/or second drive signal is modulated.
  • For the detection of contaminations on the surface, the control unit may cause modulation of the amplitude, frequency or phase shift of the ultrasonic waves produced by the one or more transducers. For example, for the detection of contaminations it is beneficial for the transducers to couple ultrasonic waves with multiple different frequencies into the surface, such that the detection of a change in the one or more characteristics may be a change in a single frequency. For example, a contamination may attenuate ultrasonic waves of a particular frequency strongly, while attenuating waves of other frequencies to a lesser degree. Thus, the control unit may be able to determine the corresponding cleaning action properly. Furthermore, the control unit may be able to infer the type of the contamination from the detected change. In cleaning the surface, the same principle applies. For example, a higher amplitude may lead to a higher transmission of energy to a contamination, which in turn may lead to faster evaporation, quicker propagation or other beneficial effects. Modulating the frequency may be beneficial in order to cause ultrasonic waves to be caused to be coupled into the surface in, thus, into the contamination the frequency of which may correspond to a resonant frequency/ eigenmode or a harmony of such a frequency of the contaminant, which causes a stronger effect of the ultrasonic waves in the contamination. Furthermore, ultrasonic waves of the resonant frequency/eigenmode or a harmony thereof of the surface may be caused to be coupled into the surface in order to cause strong vibrations in the surface.
  • In an aspect of the invention, the control unit is configured to calculate a liquid saturation of a boundary of the contamination based on a liquid flow rate of the liquid supplied by the liquid supply apparatus, and cause the portion of the one or more transducers to produce second ultrasonic waves in accordance with the determined cleaning action and in accordance with the calculated liquid saturation.
  • When the liquid saturation of the boundary of the contamination is high, the area of contact between the contamination and media which may couple the second ultrasonic waves to the contamination is increased. Thus, a more effective, reliable and efficient cleaning of the surface is facilitated. Additionally, cavitations caused in the liquid by the second ultrasonic waves may cause microjets and/micro bubbles, which in turn may loosen the contamination. When a larger proportion of the boundary of the contamination is saturated by the liquid such cavitations may have a stronger effect. Thus, by causing the portion of the one or more transducers to produce second ultrasonic waves in accordance with the calculated liquid saturation, the system is able to operate more efficiently.
  • In a general aspect of the invention, a method for clearing a contamination from a surface is provided, the method comprising: generating first ultrasonic waves coupling the first ultrasonic waves to the surface receiving at least some of the first ultrasonic waves detecting a change in one or more characteristics of a plurality of characteristics of the at least some of the first ultrasonic waves in the; determining a cleaning action for the surface from a set of predefined cleaning actions based on the detected change in the one or more characteristics; generating second ultrasonic waves coupling the second ultrasonic waves to the surface in accordance with the determined cleaning action.
  • By coupling the first ultrasonic waves to the surface, the detection of a contamination is facilitated. Detecting a change in one or more characteristics of a plurality of characteristics of the first ultrasonic waves in the received at least some of the first ultrasonic waves allows a cleaning action corresponding to the detected change to be determined and performed. Thus, the cleaning of the surface may be carried out in a better suited manner to the contamination.
  • In an aspect of the invention, the method further comprises: inferring a type of the contamination on the surface from a predefined set of types of contaminations from the detected change in the one or more characteristics; and determining the cleaning action in accordance with the inferred type of the contamination.
  • By inferring the type of the contamination, a cleaning action specifically tailored to such a contamination may be determined and performed by coupling second ultrasonic waves to the surface. For example, different types of contaminations such as e.g. ice, liquid (e.g. droplets) or mud may have different properties (e.g. density, viscosity etc.) whereby different cleaning actions may be beneficial in the removal of such contaminations. It is, thus, beneficial for the cleaning of the surface to infer the type of contamination and base the determination of the cleaning action also on the inferred type of the contamination.
  • In an aspect of the invention, the method further comprises: supplying liquid to the surface according to the determined cleaning action.
  • Supplying liquid to the surface is particularly beneficial, since some types of contamination may be more efficiently and reliably cleaned thusly. For example, mud may be more easily removed when it is dissolved in a liquid, as the liquid may be propelled by the second ultrasonic waves to the edge of the surface. Additionally, the second ultrasonic waves may be more efficiently coupled to the contamination since the contact are of the contamination to media to which the second ultrasonic waves have been coupled is enlarged. Furthermore, cavitations in the liquid caused by the second ultrasonic waves may cause loosening of the contaminations from the surface.
  • In an aspect of the invention, the method further comprises: adjusting the power level of the second ultrasonic waves in accordance with the determined cleaning action, and/or adjusting the pulsing sequence of the second ultrasonic waves in accordance with the determined cleaning action, and/or modulating the second ultrasonic waves in accordance with the determined cleaning action, including modulating at least one of the amplitude, the frequency and the phase shift of the second ultrasonic waves.
  • The benefits of such methods are described above in reference to the system according to the invention.
  • Other advantages will become apparent from the following description and the above summary is not meant to indicate essential features or limit the scope of the invention.
    • BRIEF DESCRIPTION OF THE FIGURES
  • Various aspects and embodiments will be described with reference to the following figures. It should be appreciated that the figures are not necessarily drawn to scale. Items appearing in multiple figures are indicated by the same reference number in all the figures in which they appear.
    • Fig. 1 shows an illustrative depiction of a system according to the invention for clearing a contaminations from a surface.
    • Fig. 2 shows an illustration of a change in an illustrative ultrasonic wave due to a contamination on a surface.
    • Fig. 3 shows a storage unit of the system, according to the invention.
    • Fig. 4 shows a liquid supply apparatus configured to supply liquid, preferably water, to the surface according to the invention, with an expanded view.
    • Fig. 5 shows an application of liquid, preferably water, to the surface according to the invention, with an expanded view.
    • Fig. 6 shows an exemplary predefined set of types of contaminations according to the invention.
    • Fig. 7 shows pulsed drive signal sequences for the transducers according to the invention.
    • Fig. 8 shows a pulsed drive signal for a transducers according to the invention.
    • Fig. 9 shows amplification schemes for drive signal for transducers according to the invention.
    • Fig. 10 shows a cleaning action according to the invention.
    • Fig. 11 shows a cleaning action according to the invention.
    • Fig. 12 shows a cleaning action according to the invention.
    • Fig. 13 shows a cleaning action according to the invention.
    • Fig. 14 is a schematic illustration of different ultrasonic wave types.
    DETAILED DESCRIPTION
  • Fig. 1 shows an illustrative depiction of a system according to the invention for clearing a contamination 140 from a surface 100.
  • The system comprises one or more ultrasound transducers 110, 111, 112a-d configured to couple ultrasonic waves 120, 125 to the surface 100. The system also includes at least one generator 130 configured to generate a drive signal to drive the one or more transducers 110, 111, 112a-d and a receiver 110, 111, 112a-d configured to receive at least some of the ultrasonic waves 120, 125 coupled to the surface 100 by the one or more ultrasound transducers. The oppositely arranged entities 110, 111, 112a-d may be respective transducer-receiver-pairs. For example, 110 may be one of the transducers and 110 may be the receiver that receives the ultrasonic waves 120, 125 coupled to the surface 110 by the transducer 110.
  • The system further includes a control unit 160. The control unit 160 is configured to: cause the at least one generator 130 to generate a first drive signal to drive the one or more transducers 110, 111, 112a-d; cause at least one of the one or more transducers 110, 111, 112a-d to produce first ultrasonic waves 120 in accordance with the first drive signal to couple the first ultrasonic waves 120 to the surface 100; detect a change in one or more characteristics of a plurality of characteristics of at least some of the first ultrasonic waves 120 received by the receiver 110, 111, 112a-d; determine a cleaning action for the surface 100 from a set of predefined cleaning actions based on the detected change in the one or more characteristics; cause the at least one generator 130 to generate a second drive signal in accordance with the determined cleaning action to drive at least a portion of the one or more transducers 110, 111, 112a-d; and cause the portion of the one or more transducers 110, 111, 112a-d to produce second ultrasonic waves 125 in accordance with the second drive signal to couple the second ultrasonic waves 125 to the surface 100.
  • The system, e.g. the generator 130, may comprise a power amplifier 133 configured to amplify the power of the generated first and/or second drive signals.
  • The system, e.g. the at least one generator 130, may comprises a pulse generator 135, such that the at least one generator 130 is configured to be able to produce pulsed drive signals, and wherein the control unit 160 is configured to adjust the pulse frequency and pulse duration.
  • The generator 130 and the control unit may be hosted by one or more computers 150.
  • The system may further include a transceiver 170 configured to detect environmental conditions, wherein the detectable environmental conditions include at least one of temperature, humidity and air flow, wherein the control unit 160 is configured to receive information conveying the detected environmental conditions and determine the cleaning action based also on the received information.
  • The system may further include a liquid supply apparatus 180 configured to supply liquid (185 in Fig. 4), preferably water and/or a cleaning agent, to the surface 100; wherein the control unit 160 is configured to cause the liquid supply apparatus 180 to supply the liquid 185 to the surface 100 in accordance with the determined cleaning action, as illustrated in Figs. 4 and 5 in closer view. The liquid 185 may be a medium that is configured to transfer energy from the surface 100 to the contaminant 140.
  • The system of Fig. 1 may be used for clearing a contamination 140 from a surface 100. The system shown in Fig. 1 may for example be used to execute a method for clearing a contamination 140 from a surface 100, the method comprising: generating first ultrasonic waves 120; coupling the first ultrasonic waves 120 to the surface 100; receiving at least some of the first ultrasonic waves 120; detecting a change in one or more characteristics of a plurality of characteristics of the at least some of the first ultrasonic waves 120 in the; determining a cleaning action for the surface 100 from a set of predefined cleaning actions based on the detected change in the one or more characteristics; generating second ultrasonic waves 125; coupling the second ultrasonic waves 125 to the surface 100 in accordance with the determined cleaning action.
  • In other words, an ultrasound surface cleaning system with auto-detection and/or autocleaning features is provided.
  • For the auto-detection feature, one or more transceivers (piezo material) are sensing environmental condition such as temperature and humidity. This information is used to update an auto-detection threshold.
  • For the auto-detection feature, one of the transducers may be driven at a low power (e.g., below a predetermined threshold value). The opposing transducer operates as a sensor, receiving a signal induced by the vibration along the surface. Surface contaminants change the characteristics of the received signal. Different contaminant kinds or types (such as rain, ice, mud, condensation and organics) will have different effects on the received signal. By detecting the change of characteristics in the received signal, the presence of contaminant can be detected and the type of contaminant can be distinguished. This can serve as a trigger for activating a cleaning sequence.
  • The particular cleaning mode is then triggered that is most relevant to the kind of contaminant. Different cleaning modes, with different cleaning sequence, can include: De-icing, De-fogging, De-condensation, De-mudding, De-dusting, De-matter/protein, and/or De-droplets/liquid
  • To establish different cleaning modes, ultrasonic wave parameters are adapted to the kind (type) of contaminant, the parameters including power level, number of operating channels, pulsing sequence, and/or liquid supplier timing.
  • Fig. 2 shows an illustration of a change in an illustrative ultrasonic wave due to a contamination 140 on a surface 100.
  • The system for clearing the contamination 140 from the surface 100 may be calibrated by recording a base level signal without any contamination on the surface 100 between the transducer 110 and receiver 111 (cf. Fig. 2 a)). Variations due to the dimensions of the area, distances between the transducers, etc., can be accounted for in this way in a particularly effective manner, if desired.
  • The control unit 160 may be configured to detect the change in the one or more characteristics of the at least some of the first ultrasonic waves 120 by comparing the at least some of the first ultrasonic waves 120 to the base level signal (cf. Fig. 2 b)).
  • To remove the contaminant 140 from the surface 100, characteristics of the ultrasonic wave 120, such as the frequency (cf. Fig. 2 c) indicating a prolonged pulse duration, dashed line therein indicating half of the pulse duration namely from peak to valley of the waveform) and/or waveform, can be changed to perform the determined cleaning action.
  • The detected change can be a change in the waveform or frequency characteristics of the at least some of the first ultrasonic waves 120.
  • Fig. 3 shows a storage unit of the system for clearing a contamination from a surface.
  • The control unit 160 of the system may comprise a storage unit 165 storing a database 166, wherein the stored database 166 contains associations: between the predefined set of types "cont 1, 2, ..." of contaminations 140 (cf. column 1 in database 166) and corresponding changes "ch 1, 2,..." (cf. column 2 in database 166) in one or more characteristics of the plurality of characteristics, and between the predefined set of types "cont 1, 2, ..." of contaminations 140 and corresponding cleaning actions "cla 1, 2..." (cf. column 2 in database 166) of the predefined set of cleaning actions.
  • As illustrated in Fig. 6, the predefined set of types of contaminations for the surface 100 may comprise at least one of ice 143 (cf. Fig. 6 c)), fog or condensation 145 (cf. Fig. 6 e)), mud 142 (cf. Fig. 6 b)), dust 144 (cf. Fig. 6 d)), biological matter (e.g., protein) 142 (cf. Fig. 6 b)) and liquid (e.g. droplets) 141 (cf. Fig. 6 a)). Other types are also possible. The predefined set of types of contaminations may comprise ice 143 and fog or condensation 145. Alternatively or additionally, the predefined set of types of contaminations may comprise ice 143 and mud 142. Alternatively or additionally, the predefined set of types of contaminations may comprise ice 143 and dust 144. Alternatively or additionally, the predefined set of types of contaminations may comprise ice 143 and biological matter (e.g., protein) 142. Alternatively or additionally, the predefined set of types of contaminations may comprise ice 143 and liquid 141. The predefined set of types of contaminations for the surface 100 may comprise ice 143, fog or condensation 145, mud 142, and liquid 141. The predefined set of types of contaminations for the surface 100 may comprise ice 143, fog or condensation 145, mud 142, dust 144, biological matter (e.g., protein) 142 and liquid 141.
  • Returning to Fig. 3, the control unit 160 may be configured to locate the detected change in the one or more characteristics in the database 166 and extract the corresponding type 141, 142, 143, 144, 145 ("cont 1, 2, ...") of the contamination 140 using the association between the change ("ch 1, 2,...") in the one or more characteristics and the corresponding type 141, 142, 143, 144, 145 of the contamination 140, and wherein the control unit 160 is configured to locate the extracted type 141, 142, 143, 144, 145 of the contamination 140 in the database 166 and extract the corresponding cleaning action ("cla 1, 2,...") using the association between the type 141, 142, 143, 144, 145 of contamination 140 and the corresponding cleaning action.
  • The control unit 160 may be configured to detect properties of the contamination 140 (e.g. type of liquid, such as oil or water) based on the detected change in the one or more characteristics of the at least some of the first ultrasonic waves 120.
  • The control unit 160 may be configured to detect properties of individual constituents of the contamination 140 (e.g. the size of an individual droplet, since smaller droplet can more easily evaporate while larger droplets may be moved more easily) based on the detected change in the one or more characteristics of the at least some of the first ultrasonic waves.
  • Returning to Fig. 4 and 5, the control unit 160 is configured to cause the liquid supply apparatus 180 to supply the liquid 185 to the surface 100 in accordance with the determined cleaning action. In Fig. 5, the bottom part is a closer view of the dashed rectangle in the upper part of Fig. 5. As shown in the bottom part, the transducers 110, 111, 112a-d may be configured to couple ultrasonic waves to the liquid 185 through the surface 100 and/or directly to the liquid 185. In the bottom part of Fig. 5, the two wave sections show that the waves are coupled either directly from the transducer into the liquid 185 or via the surface into the liquid 185.
  • The control unit 160 may be configured to cause the liquid supply apparatus 180 to supply liquid 185 in accordance with the detected contamination 140. The control unit 160 is further configured to: estimate the mass of the contamination 140 based on the detected change in the one or more characteristics, and cause the liquid supply apparatus 180 to supply an amount of liquid 185 in accordance with the determined cleaning action. The control unit 160 may be configured to cause the liquid supply apparatus 180 to supply an amount of liquid 185 approximately equal in mass to the estimated mass of the contamination 140.
  • As illustrated in Figures 1, 7 and 8, the at least one generator 130 comprises a pulse generator 135, such that the at least one generator 130 is configured to produce pulsed drive signals ("Signal of Trans" in Figs. 7 and 8), and wherein the control unit 160 is configured to vary the pulse frequency, pulse duration and/or phase of the pulse from transducer to transducer (cf. Fig. 7) and/or for one and the same transducer over time, as shown in Fig. 8.
  • The control unit 160 may be configured to cause synchronously and/or asynchronously pulsed ultrasonic waves to be produced by different transducers "Trans 1-4" of the portion of one or more transducers, as shown in Fig. 7.
  • For effective droplet propulsion, for example, it may be advisable to avoid droplet cavitation or evaporation. This can be achieved by decreasing the power, such as via pulsation. Liquid (e.g, droplets) can be propelled across the surface more quickly if the transducer activation is pulsed. Pulsed transducer actuation can, however, also be beneficial for other types of contamination.
  • When assuming that 110, 111, 112a and 112c in Fig. 1 would each be transducers according to the invention and would be transducers ("Trans") 4, 2, 1 and 3 of Fig. 7, respectively, then, at the four transducers Trans 1-4, a propulsion sequence may be executed, at which the left (Trans 4) and right (Trans 2) transducer are pulsed out of phase while the top (Trans 1) transducer remains activated, as illustrated in Fig. 7.
  • In particular, the propulsion sequence may include the following sequences 1, 2, 3, 4 and 5:
    Propulsion sequence 1 is performed: at which the left (Trans 4) and right (Trans 2) transducer are pulsed ou t of phase while the top (Trans 1) transducer remains activated, as illustrated in Fig. 7. The pulse duration is Xms.
  • Propulsion sequence 2 is then performed, at which the left (Trans 4) and right (Trans 2) transducer are pulsed out of phase while the top (Trans 1) transducer remains activated as illustrated in Fig. 7, but the pulse duration is repeatably chirped from Xms to Xms, increasing by Xms every cycle.
  • Propulsion sequence 3: Frequency Modulated Driving Sequence is performed.
  • Propulsion sequence 4: Phase Modulated Driving Sequence is performed.
  • Propulsion sequence 5: Amplitude Modulated Driving Sequence is performed.
  • As illustrated in Fig. 9 a), the system's power amplifier 133 may be configured to amplify the power P for the generated first and/or second drive signals, wherein the power amplifier is configured to be operable in at least two or three different modes, each mode corresponding to a different amount of amplification (gain). In Fig. 9 a) three gain levels are shown: Level high gain (e.g. double the amplification of level normal), normal gain und low gain (e.g. 0.2 times the amplification of the normal gain). The gain for a transducer can be adjusted in steps over time, can be decreased or increased continuously over time or may be increased and then reduced again (or vice versa) over time, such as in waves (cf. Fig. 9 a)).
  • The control unit 160 may be configured to cause at least some of the portion of the one or more transducers "Trans 1-3" to produce ultrasonic waves driven by differently amplified drive signals in accordance with the determined cleaning action. For different transducers, different amplification schemes can thus be applied.
  • The control unit 160 may be configured cause the power amplifier 133 to amplify the power of the generated drive signal in accordance with the received information conveying the detected environmental conditions.
  • Removing of some contaminants, such as ice, may involve activating all transducers at high power. The activation can be continuous or pulsed.
  • De-icing, for example, may occur by heating the glass and via shear action of the ice.
  • At sub-zero temperatures the piezoelectric material may be less effective. Therefore, a higher power level is preferred, as shown in Fig. 9 b), when starting the de-icing. As the temperature of the transducer and/or substrate increases, the power level can be reduced, as shown in Fig. 9 b). That is, in the de-ice mode, the transducer can be started in high power mode to warm up the surface and the transducer, and then the power is reduced.
  • De-fog mode may involve activating several or all transducers. The activation can be continuous or pulsed. The de-fogging time can be dependent on the power level.
  • De-mud/ De-matter/protein mode may involve activating several or all transducers at high power with the addition to the surface of a small quantity of a medium configured to transfer energy from the surface to the contaminant. Once the contaminant has been lifted from the surface, a propulsion sequence can be used to move the contaminant off the surface.
  • As illustrated in Figs. 1, 10, the control unit 160 is configured to choose whether - and preferably also by which amount - the amplitude, frequency and/or phase shift of the ultrasonic wave 125 is modulated based on the detected properties of the contamination 140 or properties of the individual constituents of the contamination 140, such as, for example, to force the contamination (e.g. droplet) into motion (rotational and/or translational motion) on the surface 100.
  • Fig. 11 illustrates that the one or more transducers 110, 111, 112a-d may be configured to cause cavitations 186 in the supplied liquid 185 for loosening the contaminants 140.
  • For example, once a medium, such as the liquid 185, that is configured to transfer energy from the surface 100 to the contaminant 140 is distributed across the surface it may surround the contaminant 140 at its boundary. Once the medium 185 has saturated the contaminant boundary, ultrasound is activated (cf. Fig. 11 a)). By activating ultrasound 125, the medium penetrates the contaminant through microbubble and microjets created by cavitation effect after a certain amount of time passed (cf. Fig. 6 b)). The medium and ultrasound activation times can be based on the medium's flow rate and the surface's size.
  • This approach described for Fig. 11 can have an effect on the nanoscale. For example, contaminants 140 can fill nanostructures at the surface 100, thereby reducing contact angle and coating efficacy of a coating on the surface 100. After the medium is released onto the contaminant 140 and ultrasound is activated, cavitation and microjets clear the contaminant 140 from the nanostructures, so that the contact angle at the surface 100 is enhanced, which, e.g., allows for easy removal of liquid.
  • Fig. 12 illustrates that the control unit 160 may be configured to calculate a liquid saturation of a boundary of the contamination 140 based on a liquid flow rate of the liquid 185 supplied by the liquid supply apparatus 180, and cause the portion of the one or more transducers 110, 111, 112a-d to produce second ultrasonic waves 125 in accordance with the determined cleaning action and in accordance with the calculated liquid saturation. For example, the one or more transducers ("Signal") are not switched on until one or more seconds after saturation (cf. Fig. 12 a)) and/or the transducers are allowed to continue running for one or more (e.g. two) seconds after the end of the supply of the liquid 185 (cf. Fig. 12 b)).
  • For example, ultrasound may be activated one or more second after full spread of the medium, which is configured to transfer energy from the surface to the contaminant, across the substrate is achieved. The quantity of the medium applied is relative to the contaminant characteristics detected. Ultrasound can continue to be activated for two or more seconds after the medium's supply ends to enhance proper cleaning.
  • The control unit 160 is configured to cause the at least one generator 130 to generate a second drive signal in accordance with the determined cleaning action to drive at least a portion of the one or more transducers 110, 111, 112a-d. As illustrated in Fig. 13, a standing wave may be created in the surface 100 between at least two transducers 110, 111, 112a-d of the portion of the one or more transducers.
  • Figure 14 illustrates that the one or more transducers 110, 111, 112a-d may be configured to couple waves of different types to the surface 100. Fig. 14 is a schematic illustration of different wave types.
  • The different wave types may comprise at least one of Lamb waves, longitudinal waves, shear waves, and Rayleigh waves. In Fig. 14, the top part a) of the Figure shows a Lamb Wave or Rayleigh Wave. The middle part b) of Fig. 14 shows a quasi-longitudinal wave. The bottom part c) of Fig. 14 shows a shear wave.
  • The speed (and hence wavelength) of waves in the surface 100 may vary with frequency, material properties (for example, Young's modulus, density, or Poisson ratio), and thickness of the surface material. These parameters may be known within a certain tolerance or experimentally measured. For example, a laser vibrometer may be used to accurately determine the spatial field of vibration within the surface material during the operation of the system for the purposes of obtaining a more accurate measure of the wave speeds within the surface material for refining and improving the efficiency of the transducer designs.
  • Having described several aspects and embodiments of the claimed subject-matter, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. In particular, the present invention can (alternatively) be described by one or more of the following numbered aspects:
    • ASPECTS
    1. 1. A system for clearing a contamination (140) from a surface (100), the system comprising:
      • one or more ultrasound transducers (110, 111, 112a-d) configured to couple ultrasonic waves (120, 125) to the surface (100);
      • at least one generator (130) configured to generate a drive signal to drive the one or more transducers (110, 111, 112a-d);
      • a receiver (110, 111, 112a-d) configured to receive at least some of the ultrasonic waves (120, 125) coupled to the surface (100); and
      • a control unit (160);
      wherein the control unit (160) is configured to:
      • cause the at least one generator (130) to generate a first drive signal to drive the one or more transducers (110, 111, 112a-d);
      • cause at least one of the one or more transducers (110, 111, 112a-d) to produce first ultrasonic waves (120) in accordance with the first drive signal to couple the first ultrasonic waves (120) to the surface (100);
      • detect a change in one or more characteristics of a plurality of characteristics of at least some of the first ultrasonic waves (120) received by the receiver (110, 111, 112a-d);
      • determine a cleaning action for the surface (100) from a set of predefined cleaning actions based on the detected change in the one or more characteristics;
      • cause the at least one generator (130) to generate a second drive signal in accordance with the determined cleaning action to drive at least a portion of the one or more transducers (110, 111, 112a-d); and
      • cause the portion of the one or more transducers (110, 111, 112a-d) to produce second ultrasonic waves (125) in accordance with the second drive signal to couple the second ultrasonic waves (125) to the surface (100).
    2. 2. The system of aspect 1, wherein the control unit (160) is further configured to infer a type (141, 142, 143, 144, 145) of the contamination (140) on the surface (100) from a predefined set of types of contaminations from the detected change in the one or more characteristics of the at least some of the first ultrasonic waves (120), and wherein the determined cleaning action corresponds to the inferred type (141, 142, 143, 144, 145) of the contamination (140).
    3. 3. The system of any one of the preceding aspects, wherein the control unit (160) is configured to detect the change in the one or more characteristics of the at least some of the first ultrasonic waves (120) by comparing the at least some of the first ultrasonic waves (120) to a base level signal.
    4. 4. The system of any one of the preceding aspects, wherein the detected change is a change in the waveform or frequency characteristics of the at least some of the first ultrasonic waves (120).
    5. 5. The system of any one of the preceding aspects, wherein the detected change is at least one of the power level, the frequency spectrum and the amplitude of the ultrasonic detection waves.
    6. 6. The system of any one of the preceding aspects, wherein the one or more transducers (110, 111, 112a-d) comprise at least two transducers (110, 111, 112a-d), and
      wherein one of the at least two transducers (110, 111, 112a-d) functions as the receiver (110, 111, 112a-d).
    7. 7. The system of any of the preceding aspects, wherein the control unit (160) is configured to assess, whether the detected change in the one or more characteristics crosses a threshold value, such that the cleaning action to be performed is only determined and/or performed when the detected change in the one or more characteristics crosses the threshold value.
    8. 8. The system of aspect 7, further comprising:
      • a transceiver (170) configured to detect environmental conditions,
      • wherein the detectable environmental conditions include at least one of temperature, humidity and air flow,
      • wherein the control unit (160) is configured to receive information conveying the detected environmental conditions and determine the cleaning action based also on the received information.
    9. 9. The system of aspect 8 wherein the control unit (160) is configured to adapt the threshold value to the environmental conditions based on the received information.
    10. 10. The system of any one of aspects 2 to 9, wherein the control unit (160) comprises a storage unit (165) storing a database (166), wherein the stored database (166) contains associations:
      • between the predefined set of types of contamination (140)s and corresponding changes in one or more characteristics of the plurality of characteristics, and
      • between the predefined set of types of contamination (140)s and corresponding cleaning actions of the predefined set of cleaning actions,
      • wherein the control unit (160) is configured to locate the detected change in the one or more characteristics in the database (166) and extract the corresponding type (141, 142, 143, 144, 145) of the contamination (140) using the association between the change in the one or more characteristics and the corresponding type (141, 142, 143, 144, 145) of the contamination (140), and
      • wherein the control unit (160) is configured to locate the extracted type (141, 142, 143, 144, 145) of the contamination (140) in the database (166) and extract the corresponding cleaning action using the association between the type (141, 142, 143, 144, 145) of contamination (140) and the corresponding cleaning action.
    11. 11. The system of any one of the preceding aspects, further comprising:
      • a liquid supply apparatus (180) configured to supply liquid (185), preferably water, to the surface (100);
      • wherein the control unit (160) is configured to cause the liquid supply apparatus (180) to supply liquid (185) to the surface (100) in accordance with the determined cleaning action.
    12. 12. The system of aspect 11, wherein the transducers (110, 111, 112a-d) are configured to couple ultrasonic waves to the liquid (185) through the surface (100) and/or directly.
    13. 13. The system of any one of aspects 11 and 12, wherein the control unit (160) is configured to cause the liquid supply apparatus (180) to supply liquid (185) in accordance with the detected contamination (140).
    14. 14. The system of aspect 13, wherein the control unit (160) is further configured to:
      • estimate the mass of the contamination (140) based on the detected change in the one or more characteristics, and
      • cause the liquid supply apparatus (180) to supply an amount of liquid (185) in accordance with the determined cleaning action.
    15. 15. The system of any one of aspects 13 or 14, wherein the control unit (160) is configured to cause the liquid supply apparatus (180) to supply an amount of liquid (185) approximately equal in mass to the estimated mass of the contamination (140).
    16. 16. The system of any of one of aspects 2 to 15, wherein the predefined set of types of contaminations comprises at least one of ice (143), fog/condensation (145), mud (142), dust (144), biological matter (142) and liquid (141).
    17. 17. The system of any of the preceding aspects, wherein the control unit (160) is configured to detect properties of the contamination (140) based on the detected change in the one or more characteristics of the at least some of the first ultrasonic waves (120).
    18. 18. The system of any of the preceding aspects, wherein the control unit (160) is configured to detect properties of individual constituents of the contamination (140) based on the detected change in the one or more characteristics of the at least some of the first ultrasonic waves (120).
    19. 19. The system of any of the preceding aspects, wherein the system comprises a power amplifier (133) configured to amplify the power of the generated first and/or second drive signals.
    20. 20. The system of aspect 19, wherein the power amplifier (133) is configured to be operable in at least two different modes, each mode corresponding to a different amount of amplification.
    21. 21. The system of aspect 20, wherein the control unit (160) is configured to cause at least some of the portion of the one or more transducers (110, 111, 112a-d) to produce ultrasonic waves driven by differently amplified drive signals in accordance with the determined cleaning action.
    22. 22. The system of any of the preceding aspects, wherein the at least one generator (130) comprises a pulse generator (135), such that the at least one generator (130) is configured to be able to produce pulsed drive signals, and
      wherein the control unit (160) is configured to adjust the pulse frequency and pulse duration.
    23. 23. The system of aspect 22, wherein the control unit (160) is configured to cause synchronously and/or asynchronously pulsed ultrasonic waves to be produced by different transducers (110, 111, 112a-d) of the portion of one or more transducers (110, 111, 112a-d).
    24. 24. The system of any of the preceding aspects, wherein the control unit (160) is configured to cause the at least one generator (130) to modulate the second drive signal in accordance with the determined cleaning action, wherein at least one of the amplitude, the frequency and the phase shift of the second drive signal is modulated.
    25. 25. The system of aspect 24, wherein control unit (160) is configured to choose whether the amplitude, frequency or phase shift is modulated based on the detected properties of the contamination (140) or properties of the individual constituents of the contamination (140).
    26. 26. The system of any one of aspects 19 to 25, wherein the control unit (160) is configured cause the power amplifier (133) to amplify the power of the generated drive signal in accordance with the received information conveying the detected environmental conditions.
    27. 27. The system of aspect any one of aspects 11 to 26, wherein the transducers (110, 111, 112a-d) are configured to cause cavitations (186) in the supplied liquid (185) for loosening the contaminants.
    28. 28. The system of any one of aspects 11 to 27, wherein the control unit (160) is configured to calculate a liquid saturation of a boundary of the contamination (140) based on a liquid flow rate of the liquid (185) supplied by the liquid supply apparatus (180), and
      cause the portion of the one or more transducers (110, 111, 112a-d) to produce second ultrasonic waves (125) in accordance with the determined cleaning action and in accordance with the calculated liquid saturation.
    29. 29. The system of any one of aspects 11 to 28, wherein the liquid (185) contains a cleaning agent.
    30. 30. The system of aspect 29, wherein the liquid supply apparatus (180) is configured to add the cleaning agent to the liquid (185), and
      wherein the control unit (160) is configured to cause the cleaning apparatus to mix the liquid (185) with the cleaning agent at a ratio in accordance with the determined cleaning action.
    31. 31. The system of any one of the preceding aspects, wherein a standing wave is created in the surface (100) between at least two transducers (110, 111, 112a-d) of the portion of the one or more transducers (110, 111, 112a-d).
    32. 32. The system of any one of the preceding aspects, wherein the transducers (110, 111, 112a-d) are configured to couple waves of different types to the surface (100).
    33. 33. The system of aspect 32, wherein the different wave types comprise at least one of Lamb waves, shear waves, and Rayleigh waves.
    34. 34. A method for clearing a contamination (140) from a surface (100), the method comprising:
      • generating first ultrasonic waves (120);
      • coupling the first ultrasonic waves (120) to the surface (100);
      • receiving at least some of the first ultrasonic waves (120);
      • detecting a change in one or more characteristics of a plurality of characteristics of the at least some of the first ultrasonic waves (120) in the;
      • determining a cleaning action for the surface (100) from a set of predefined cleaning actions based on the detected change in the one or more characteristics;
      • generating second ultrasonic waves (125);
      • coupling the second ultrasonic waves (125) to the surface (100) in accordance with the determined cleaning action.
    35. 35. The method of aspect 34, further comprising:
      • inferring a type (141, 142, 143, 144, 145) of the contamination (140) on the surface (100) from a predefined set of types of contaminations from the detected change in the one or more characteristics; and
      • determining the cleaning action in accordance with the inferred type (141, 142, 143, 144, 145) of the contamination (140).
    36. 36. The method of any one of aspects 34 and 35, further comprising:
      detecting the change in the one or more characteristics of the received at least some of the first ultrasonic waves (120) by comparing the received at least some of the first ultrasonic waves (120) to a base level signal.
    37. 37. The method of any one of aspects 34 to 36, further comprising:
      • assessing, whether the detected change in the one or more characteristics crosses a threshold value; and
      • determining the cleaning action and/or coupling the ultrasonic cleaning waves to the surface (100) in accordance with the determined cleaning action only when the detected change in the one or more characteristics crosses the threshold value.
    38. 38. The method of aspect 37, further comprising:
      • receiving information conveying detected environmental conditions; and
      • determining the cleaning action based also on the received information.
    39. 39. The method of aspect 38, further comprising:
      adapting the threshold value to the environmental conditions in accordance with the received information.
    40. 40. The method of any one of aspects 34 to 39, further comprising:
      supplying liquid (185) to the surface (100) according to the determined cleaning action.
    41. 41. The method of any one of aspects 34 to 40, further comprising:
      detecting properties of the contamination (140) based on the detected change in the one or more characteristics of the at least some of the first ultrasonic waves (120).
    42. 42. The method of any one of aspects 34 to 41, further comprising:
      detecting properties of individual constituents of the contamination (140) based on the detected change in the one or more characteristics of the at least some of the first ultrasonic waves (120).
    43. 43. The method of any one of aspects 34 to 42, further comprising:
      adjusting the power level of the second ultrasonic waves (125) in accordance with the determined cleaning action.
    44. 44. The method of any one of aspects 34 to 43, further comprising:
      adjusting the pulsing sequence of the second ultrasonic waves (125) in accordance with the determined cleaning action.
    45. 45. The method of any one of aspects 34 to 44, further comprising:
      modulating the second ultrasonic waves (125) in accordance with the determined cleaning action, including modulating at least one of the amplitude, the frequency and the phase shift of the second ultrasonic waves (125).
    46. 46. The method of aspect 45, further comprising:
      modulating the second ultrasonic waves (125) based on the detected properties of the contamination (140) or properties of the individual constituents of the contamination (140).
    47. 47. The method of any one of aspects 40 to 46, further comprising:
      • calculating a liquid saturation of a boundary of the contamination (140) based on a liquid flow rate of the supplied liquid (185), and
      • coupling the second ultrasonic waves (125) to the surface (100) in accordance with the determined cleaning action and in accordance with the calculated liquid saturation.
    48. 48. The method of any one of aspects 34 to 47, further comprising:
      creating a standing wave in the surface (100).
    49. 49. Use of the system of any one of aspects 1 to 33 for clearing a contamination (140) from a surface (100).
  • Further, though advantages of the present invention are indicated, it should be appreciated that not every embodiment of the invention described herein will include every described advantage. Some aspects and embodiments may not implement any features described as advantageous herein and in some instances one or more of the described features may be implemented to achieve further embodiments. Accordingly, this description and these drawings are by way of example only.
  • Having described several aspects and embodiments of this invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this invention, and are intended to be within the scope of the invention as defined by the appended claims.
  • The various aspects and embodiments described above can be combined to provide yet further embodiments. These and other changes can be made to the embodiments in light of the abovedetailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific aspects and embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled.

Claims (15)

  1. A system for clearing a contamination from a surface (100), the system comprising:
    one or more ultrasound transducers (110, 111, 112a-d) configured to couple ultrasonic waves (120, 125) to the surface (100);
    at least one generator (130) configured to generate a drive signal to drive the one or more transducers (110, 111, 112a-d);
    a receiver (110, 111, 112a-d) configured to receive at least some of the ultrasonic waves (120, 125) coupled to the surface (100); and
    a control unit (160);
    wherein the control unit (160) is configured to:
    cause the at least one generator (130) to generate a first drive signal to drive the one or more transducers (110, 111, 112a-d);
    cause at least one of the one or more transducers (110, 111, 112a-d) to produce first ultrasonic waves (120) in accordance with the first drive signal to couple the first ultrasonic waves (120) to the surface (100);
    detect a change in one or more characteristics of a plurality of characteristics of at least some of the first ultrasonic waves (120) received by the receiver (110, 111, 112a-d);
    determine a cleaning action for the surface (100) from a set of predefined cleaning actions based on the detected change in the one or more characteristics;
    cause the at least one generator (130) to generate a second drive signal in accordance with the determined cleaning action to drive at least a portion of the one or more transducers (110, 111, 112a-d); and
    cause the portion of the one or more transducers (110, 111, 112a-d) to produce second ultrasonic waves (125) in accordance with the second drive signal to couple the second ultrasonic waves (125) to the surface (100).
  2. The system of claim 1, wherein the control unit (160) is further configured to infer a type (141, 142, 143, 144, 145) of the contamination (140) on the surface (100) from a predefined set of types of contaminations from the detected change in the one or more characteristics of the at least some of the first ultrasonic waves (120), and wherein the determined cleaning action corresponds to the inferred type (141, 142, 143, 144, 145) of the contamination (140), wherein the predefined set of types of contaminations comprises at least one of ice (143), fog/condensation (145), mud (142), dust (144), biological matter (142) and liquid (141).
  3. The system of any one of the preceding claims, wherein the control unit (160) is configured to detect the change in the one or more characteristics of the at least some of the first ultrasonic waves (120) by comparing the at least some of the first ultrasonic waves (120) to a base level signal, and/or wherein the detected change is a change in the waveform and/or frequency characteristics of the at least some of the first ultrasonic waves (120), wherein, preferably, the detected change is at least one of the power level, the frequency spectrum and/or the amplitude of the ultrasonic detection waves.
  4. The system of any one of the preceding claims, wherein the one or more transducers (110, 111, 112a-d) comprise at least two transducers (110, 111, 112a-d), and wherein one of the at least two transducers (110, 111, 112a-d) functions as the receiver (110, 111, 112a-d).
  5. The system of any of the preceding claims, wherein the control unit (160) is configured to assess, whether the detected change in the one or more characteristics crosses a threshold value, such that the cleaning action to be performed is only determined and/or performed when the detected change in the one or more characteristics crosses the threshold value, wherein the system preferably further comprises:
    a transceiver (170) configured to detect environmental conditions, wherein the detectable environmental conditions include at least one of temperature, humidity and air flow, wherein the control unit (160) is configured to receive information conveying the detected environmental conditions and determine the cleaning action based also on the received information, and wherein, preferably, the control unit (160) is configured to adapt the threshold value to the environmental conditions based on the received information.
  6. The system of any one of the preceding claims, further comprising:
    a liquid supply apparatus (180) configured to supply liquid (185), preferably water, to the surface (100); wherein the control unit (160) is configured to cause the liquid supply apparatus (180) to supply liquid (185) to the surface (100) in accordance with the determined cleaning action, preferably wherein the transducers (110, 111, 112a-d) are configured to couple ultrasonic waves to the liquid (185) through the surface (100) and/or directly, and/or wherein the control unit (160) is configured to cause the liquid supply apparatus (180) to supply liquid (185) in accordance with the detected contamination (140).
  7. The system of any of the preceding claims, wherein the system comprises a power amplifier (133) configured to amplify the power of the generated first and/or second drive signals; wherein the power amplifier (133) is configured to be operable in at least two different modes, each mode corresponding to a different amount of amplification; wherein the control unit (160) is configured to cause at least some of the portion of the one or more transducers (110, 111, 112a-d) to produce ultrasonic waves driven by differently amplified drive signals in accordance with the determined cleaning action.
  8. The system of any of the preceding claims, wherein the at least one generator (130) comprises a pulse generator (135), such that the at least one generator (130) is configured to be able to produce pulsed drive signals, and wherein the control unit (160) is configured to adjust the pulse frequency and pulse duration, preferably wherein the control unit (160) is configured to cause synchronously and/or asynchronously pulsed ultrasonic waves to be produced by different transducers (110, 111, 112a-d) of the portion of one or more transducers (110, 111, 112a-d).
  9. The system of any of the preceding claims, wherein the control unit (160) is configured to cause the at least one generator (130) to modulate the second drive signal in accordance with the determined cleaning action, wherein at least one of the amplitude, the frequency and the phase shift of the second drive signal is modulated.
  10. The system of any one of claims 6 to 9, wherein the control unit (160) is configured to calculate a liquid saturation of a boundary of the contamination (140) based on a liquid flow rate of the liquid (185) supplied by the liquid supply apparatus (180), and
    cause the portion of the one or more transducers (110, 111, 112a-d) to produce second ultrasonic waves (125) in accordance with the determined cleaning action and in accordance with the calculated liquid saturation.
  11. A method for clearing a contamination (140) from a surface (100), the method comprising:
    generating first ultrasonic waves (120);
    coupling the first ultrasonic waves (120) to the surface (100);
    receiving at least some of the first ultrasonic waves (120);
    detecting a change in one or more characteristics of a plurality of characteristics of the at least some of the first ultrasonic waves (120) in the;
    determining a cleaning action for the surface (100) from a set of predefined cleaning actions based on the detected change in the one or more characteristics;
    generating second ultrasonic waves (125); and
    coupling the second ultrasonic waves (125) to the surface (100) in accordance with the determined cleaning action.
  12. The method of claim 11, further comprising:
    inferring a type (141, 142, 143, 144, 145) of the contamination (140) on the surface (100) from a predefined set of types of contaminations from the detected change in the one or more characteristics; and
    determining the cleaning action in accordance with the inferred type (141, 142, 143, 144, 145) of the contamination (140).
  13. The method of any one of claims 11 to 12, further comprising: supplying liquid (185) to the surface (100) according to the determined cleaning action.
  14. The method of any one of claims 11 to 13, further comprising:
    adjusting the power level of the second ultrasonic waves (125) in accordance with the determined cleaning action, and/or
    adjusting the pulsing sequence of the second ultrasonic waves (125) in accordance with the determined cleaning action, and/or
    modulating the second ultrasonic waves (125) in accordance with the determined cleaning action, including modulating at least one of the amplitude, the frequency and the phase shift of the second ultrasonic waves (125).
  15. Use of the system of any one of claims 1 to 10 for clearing a contamination (140) from a surface (100).
EP24205244.7A 2024-10-08 2024-10-08 System for ultrasonic cleaning Pending EP4725620A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP24205244.7A EP4725620A1 (en) 2024-10-08 2024-10-08 System for ultrasonic cleaning
PCT/EP2025/077766 WO2026077741A1 (en) 2024-10-08 2025-09-29 System for ultrasonic cleaning

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP24205244.7A EP4725620A1 (en) 2024-10-08 2024-10-08 System for ultrasonic cleaning

Publications (1)

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EP4725620A1 true EP4725620A1 (en) 2026-04-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP24205244.7A Pending EP4725620A1 (en) 2024-10-08 2024-10-08 System for ultrasonic cleaning

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EP (1) EP4725620A1 (en)
WO (1) WO2026077741A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11351579B2 (en) * 2014-02-24 2022-06-07 The Boeing Company System and method for surface cleaning
US20240181995A1 (en) * 2021-03-31 2024-06-06 Universite De Lille Device for cleaning an optical surface
EP4095002B1 (en) * 2020-02-17 2024-07-31 Huawei Technologies Co., Ltd. Vehicle window cleaning method, vehicle window cleaning apparatus, and vehicle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11351579B2 (en) * 2014-02-24 2022-06-07 The Boeing Company System and method for surface cleaning
EP4095002B1 (en) * 2020-02-17 2024-07-31 Huawei Technologies Co., Ltd. Vehicle window cleaning method, vehicle window cleaning apparatus, and vehicle
US20240181995A1 (en) * 2021-03-31 2024-06-06 Universite De Lille Device for cleaning an optical surface

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