Contact detection using ultrasonic sensor systems

Abstract

This invention relates to a method for contact detection of an ultrasonic sensor system installed in a concealed or unconcealed manner, comprising the following steps: detecting reference environmental information (100) using an ultrasonic sensor of the ultrasonic sensor system, the reference environmental information including a time curve of a signal having: noise signal information related to a wall material and / or airborne sound signal information; storing the reference environmental information (200); detecting real-time environmental information (300) using an ultrasonic sensor, the real-time environmental information including a time curve of a signal having: noise signal information related to a wall material and / or airborne sound signal information and / or object sound signal information related to an object contacting the wall material; and forming a difference signal (400) between the environmental information of the reference environmental information and the real-time environmental information using a computing unit. The difference signal can be interpreted in a further step. The invention also relates to a system having means for performing the steps of the method. Furthermore, the invention relates to a vehicle having the system. The invention also relates to computer programs, data carrier signals, and computer-readable media.

Description

Technical Field

[0001] This invention relates to a method for contact detection using an ultrasonic sensor system, particularly computational contact detection by actively exciting and detecting noise signals using an ultrasonic sensor system installed in a concealed or uncovered manner, especially for vehicles.

[0002] The present invention also relates to a system for contact detection using an ultrasonic sensor system, which is particularly suitable for computational contact detection by actively exciting and detecting noise signals using an ultrasonic sensor system installed in a concealed or uncovered manner, especially for vehicles.

[0003] Furthermore, the present invention relates to a vehicle having such a system.

[0004] The present invention also relates to a computer program including instructions that, when executed by a computer, cause the computer to perform the steps of the method.

[0005] The present invention also relates to a data carrier signal for transmitting computer programs.

[0006] The present invention also relates to a computer-readable medium including instructions that, when executed by a computer, cause the computer to perform the steps of the method. Background Technology

[0007] Ultrasonic transducers or ultrasonic sensor systems used to monitor the vehicle environment are typically installed in a concealed manner, meaning that there are openings in the vehicle wall material in the area of ​​the ultrasonic transducer.

[0008] Concealed installation of ultrasonic transducers or ultrasonic sensor systems (and therefore invisible from the outside) is visually preferred, but has not been largely proven in itself because parasitic structural acoustic amplitudes in the adjacent vehicle structure, particularly in its wall material, which are thus generated during ultrasonic signal transmission and attenuate only slowly without further measures, significantly hinder the reliable detection of ultrasonic signals coupled in echo form through the air propagation path.

[0009] For example, in a vehicle, a concealed ultrasonic sensor system means that one or more ultrasonic sensors are not visible from the outside, that is, not visible on the vehicle's exterior. The ultrasonic signals emitted by the ultrasonic sensor system penetrate the wall material on which the sensors are arranged. In this process, the ultrasonic signals penetrate the wall material twice for ultrasonic detection, particularly during the transmission and reception of the ultrasonic signals by the concealed ultrasonic sensor system. During this process, the wall material vibrates. These vibrations resonate for such a long time that they interfere with the measurement of the echo time of flight.

[0010] Whether in a concealed or uncovered ultrasonic sensor system, computational contact detection is currently hampered by various measurement influences, particularly noise or structural acoustics. Different approaches exist to address this issue in order to enable contact detection, ideally avoiding the active excitation of noise signals. In this case, active excitation of noise signals means that the sensor unit explicitly excites the noise and receives the corresponding detection signal based on this explicit noise excitation.

[0011] For example, published patent application DE102014014389A1 relates to the detection of contact events using a structure acoustic sensor. This structure acoustic sensor is designed separately from an ultrasonic sensor, but utilizes its signal processing device. Contact detection is passive. Therefore, there is no active excitation of noise, particularly structure acoustic.

[0012] The teachings of published patent application DE102006012336A1 are also known. This discloses the use of piezoelectric coatings for contact detection in keyless vehicle entry systems. It also mentions that parking bumps can be detected using this coating. Here, the measurement is not performed by an ultrasonic sensor, and there is no active excitation of noise, particularly structural sound.

[0013] The teachings of published patent application DE102017109009A1 are also known. This discloses a method for detecting contact events on a vehicle body. In this case, a structure sound signal is detected by a structure sound sensor. The structure sound signal is evaluated by an evaluation device to determine the area on the vehicle body that was touched. Based on this location, it is determined whether there is intentional vandal damage or collision damage. The measurement is performed by a structure sound sensor, not by an ultrasonic sensor system. Furthermore, no active excitation of noise, specifically structure sound, is provided.

[0014] The teachings of published patent application DE102017106749A1 are also known. This discloses a method for determining damage to a motor vehicle. In this method, an ultrasonic sensor is used to detect structural acoustic waves generated by external forces acting on motor vehicle components. The noise is not actively excited, and reflections from the vehicle body that reach the ultrasonic sensor again are not evaluated. Therefore, this is not an active measurement.

[0015] Another prior art is the published patent application DE10034524A1. This discloses the measurement of structural acoustic spectrum for the purpose of detecting damage (deformation caused by an accident). For this purpose, a special pulse generator is provided to excite the body of a motor vehicle. The structural acoustic sensor then measures the resulting structural acoustic spectrum and compares it with a reference measurement. Summary of the Invention

[0016] Based on the above-mentioned prior art, the present invention is therefore based on the purpose of improving the contact detection method.

[0017] According to the invention, this objective is achieved by the features of the independent claim. Advantageous configurations of the invention are specified in the dependent claims.

[0018] Therefore, the present invention provides a method for contact detection of an ultrasonic sensor system installed in a concealed or uncovered manner. In particular, the method is intended for use with vehicles having wall materials. The method comprises the following steps: detecting reference environmental information using an ultrasonic sensor of the ultrasonic sensor system, the reference environmental information including a time curve of a signal having: noise signal information and / or airborne sound signal information related to the wall material (particularly of the vehicle); storing the reference environmental information; detecting real-time environmental information using the ultrasonic sensor, the real-time environmental information including a time curve of a signal having: noise signal information and / or airborne sound signal information related to the wall material and / or object sound signal information related to an object contacting the wall material; and forming a difference signal between the environmental information of the reference environmental information and the real-time environmental information using a computing unit.

[0019] In the specification and appended claims, the detection of environmental information, particularly reference environmental information and real-time environmental information, is understood to mean the generation of ultrasonic waves, particularly ultrasonic signals or ultrasonic pulses, as well as the associated excitation of the wall material and the emission of ultrasonic waves, and the subsequent measurement of vibrations, particularly vibrations of the wall material, by means of an ultrasonic sensor.

[0020] The method for contact detection is preferably a method for calculating noise compensation, specifically a method for calculating structure-based acoustic compensation.

[0021] Preferably, the final step of the method according to the invention is performed in a vehicle.

[0022] The present invention also specifies a system for contact detection of an ultrasonic sensor system installed in a concealed or uncovered manner, particularly for vehicles with wall materials. The system has:

[0023] An ultrasonic sensor system having one or more ultrasonic sensors, configured to detect reference environmental information, wherein the reference environmental information includes a time profile of a signal having: noise signal information related to the wall material and / or airborne acoustic signal information;

[0024] A storage device configured to store reference environment information;

[0025] One or more ultrasonic sensors are configured to detect real-time environmental information, wherein the real-time environmental information includes a time profile of a signal having: noise signal information related to the wall material and / or airborne sound signal information and / or object sound signal information related to an object in contact with the wall material; and a computing unit configured to form a difference signal between the environmental information of the reference environmental information and the real-time environmental information. The system preferably has means configured to perform at least one step according to one of the preferred embodiments described below.

[0026] The present invention also specifies a vehicle having the system. The vehicle is preferably a driver's private vehicle.

[0027] Furthermore, this invention provides a computer program comprising instructions that, when executed by a computer, cause the computer to perform the steps of the method. A computer program is a collection of instructions designed to perform a specific task aimed at solving a particular class of problems. The instructions of a program are designed to be executed by a computer, and a computer must be able to execute a program to run.

[0028] The present invention also specifies a data carrier signal for transmitting computer programs.

[0029] The present invention also provides a computer-readable medium including instructions that, when executed by a computer, cause the computer to perform the steps of the method.

[0030] Therefore, the basic idea of ​​this invention is to introduce ultrasonic signals into the wall material and identify interference signals, particularly structural acoustic interference signals, as reference noise information related to the wall material. After real-time noise information related to the wall material has been detected accordingly, the difference between the real-time noise information and the reference noise information is determined. This difference is practically zero as long as the conditions of the vehicle wall remain unchanged. This difference is highly sensitive to interference, and therefore can even detect contact with the vehicle's outer wall. Damage or scratching processes on the outer wall can also be detected in this way. According to the invention, it is therefore possible to accurately detect changes in noise patterns, particularly structural acoustic patterns, during contact detection, with associated high sensitivity.

[0031] According to the present invention, the structure sound spectrum was not determined, but changes in reflected noise, particularly structure sound, were detected.

[0032] In other words, this invention is based on the principle of detecting signal changes. Temperature-related changes in noise can also be considered during the latter's compensation calculations. Therefore, this method allows for reliable detection using an ultrasonic sensor system, where the system, mounted under, for example, a wall material, can have multiple ultrasonic sensors that can simultaneously and continuously detect, resulting in consistently accurate detection results. The proposed method allows for significant reductions in design and material costs, and thus potentially significant reductions in cost and weight, while the performance of concealed ultrasonic detection systems is comparable to or even improved. This method for compensating for structural acoustics can also be used in concealed ultrasonic detection systems, where the corresponding signal generated by the reverberation of the membrane and which can also be interpreted as structural acoustics is removed through calculations for each measurement. In this case, the membrane is formed, for example, a wall material. In an unconcealed configuration of the ultrasonic transducer, the quality of detection results at small distances (e.g., close to 10 cm) is improved.

[0033] According to the present invention, the evaluation of the difference signal can be used not only to detect contacts that produce structured sound, but also to detect contacts that do not produce either airborne or structured sound. Static contacts can also be detected. In principle, large-area and point-like contacts can be detected.

[0034] For example, if the relevant wall materials of the vehicle, particularly the vehicle shell, allow for sufficient propagation of structural sound, especially in the case of metallic materials, hard plastics, and glass, then methods for contact detection can be used. Therefore, all areas of the vehicle shell, especially the following configurations, facilitate the application of this method.

[0035] For example, this invention can be used in conjunction with a keyless entry system to identify which door / hatch will be opened based on contact. A keyless entry system is a system that unlocks a vehicle when a hand is within a few centimeters of the door handle of a vehicle equipped with the system. In this case, the system is awakened from a so-called "sleep mode" by means of an always-active onboard capacitive or optical proximity sensor and transmits a coded request signal via multiple antennas distributed throughout the vehicle. The onboard system then enters a receiving mode and waits for confirmation. If the key is within range, it receives the signal at a specific frequency, decodes it, and actively transmits it again with a new code. Inside the vehicle, the control unit decodes it again. Since the system knows both coding tables, it can compare its original transmitted signal with the signal just received. If there is no correct response within a defined time, nothing happens, and the system switches back to standby. Pulling the door handle has no effect because the state of the door lock is not changed by the system. However, if the two codes match, this results in authentication, the onboard system releases the lock, and pulling the handle unlocks the door.

[0036] It is conceivable that concealed ultrasonic transducers already present in vehicles could be used for routine environmental monitoring or object detection. Conversely, concealed ultrasonic transducers for contact detection could also be used simultaneously for environmental monitoring, object detection, or as proximity sensors.

[0037] In principle, pre-stored reference environment information, especially noise signal information, can be obtained. These detections can be performed, for example, by using a sound absorber, such as in a suitably configured sound studio.

[0038] Ultrasound is understood as sound with frequencies above the range of human hearing. It preferably includes frequencies starting from 16 kHz. Sounds with frequencies above approximately 1 GHz are also called ultrasound. In contrast, frequencies below the range of human hearing are called infrasound.

[0039] In gases and liquids, ultrasound propagates as longitudinal waves. In solids, it also propagates as transverse waves due to the resulting shear stress. The transition from airborne sound to solid sound, or vice versa, can be achieved, for efficiency reasons, by using coupling media with suitable acoustic impedance and specific thickness.

[0040] Depending on the material of the obstacle, ultrasonic waves can be reflected, absorbed, scattered, or transmitted. As with other waves, refraction, diffraction, and interference also occur, resulting in the design of highly sensitive ultrasonic systems.

[0041] Air exhibits damping of ultrasound waves, and this damping increases sharply with frequency. Air damping also depends on air temperature and humidity. In contrast, ultrasound waves propagate with low damping in liquids.

[0042] Therefore, the first step of this method is to detect reference environment information.

[0043] This invention does not require differentiation between single or multiple pieces of information, as doing so does not contribute to the inventive step. Furthermore, the reference environmental information may include only noise signal information and / or airborne sound signal information related to the wall material. In other words, the word "one" is used as an indefinite article rather than a numeral.

[0044] Wall material is considered to be the exterior wall of a vehicle, such as body panels or Gorilla glass used in sliding roofs.

[0045] Noise signal information refers to signal information that appears in addition to the expected sound detection and may interfere with it. It is this signal information that needs to be compensated.

[0046] Airborne acoustic signals are considered to be ultrasonic waves located outside the wall material.

[0047] Next, the reference environment information is stored. This step can be performed once or repeatedly, depending on the defined conditions. For this method to be effective, it is important that the reference environment information detected in previous steps is retrieveable at a later time.

[0048] If the reference environmental information is stored as searchable, ultrasonic sensors are used to detect real-time environmental information, including noise signal information related to the wall material, particularly structural acoustic signals, and / or airborne acoustic signals and / or object acoustic signals related to objects in contact with the wall material. Characteristic signals of objects, such as a hand placed on the wall material, can be detected. In this way, other real-time information is detected in addition to the existing reference information. If the distance to the detected object changes between different detection times, this is also detected.

[0049] The acoustic signal information of the object is considered to be ultrasonic waves located outside the wall material and generated by the object touching the wall material. It is information that does not correspond to noise signal information or airborne acoustic signal information.

[0050] Finally, a difference signal is generated between each piece of environmental information in the reference and real-time environmental information using a computational unit. In this way, the reference measurement is subtracted from the subsequent real-time measurement in the time domain. In this case, the reference environmental information can be subtracted from the real-time environmental information, or vice versa. It should be noted that the computational algorithm is uniformly configured.

[0051] The subsequent steps are performed according to existing technology, that is, as in the case of an externally mounted ultrasonic sensor. For example, a signal is typically used, in this case a differential signal, to check for any event, such as a threshold being exceeded.

[0052] According to an advantageous embodiment of the invention, the ultrasonic sensor is a distance sensor. According to an advantageous embodiment of the invention, the ultrasonic sensor system is installed in a concealed manner. In other words, noise, especially structure noise, is measured by ultrasonic sensors that are concealed and also function as distance sensors.

[0053] According to an advantageous embodiment of the invention, the wall material of the vehicle has a thickness of at least 0.1 mm and at most 3.0 mm. With this wall material thickness, suitable sensitivity for the ultrasonic sensor has been advantageously discovered.

[0054] According to an advantageous embodiment, the invention is characterized by smoothing and / or filtering the difference signal. The difference signal prepared for subsequent calculations enables more reliable or less error-prone detection of the vehicle environment.

[0055] According to an advantageous embodiment of the invention, the frequency of the ultrasonic sensor is at least 40 kHz to 80 kHz. It has been found that noise, particularly structural noise, in this frequency range can be well compensated for, thereby enabling reliable or error-free detection of the vehicle environment.

[0056] According to an advantageous embodiment of the invention, a difference signal between various environmental information points is formed based on the raw data, the envelope, and / or another filtered received signal, such as the correlation with the transmitted signal of an ultrasonic sensor. The raw data only requires reduced computational power, thereby accelerating data utilization.

[0057] According to an advantageous embodiment of the invention, reference environment information is repeatedly detected at defined time intervals. In principle, any detected reference environment information may also include detected objects. To enable the most reliable and accurate detection, in one embodiment, the reference environment information is detected at regular time intervals. According to an advantageous embodiment of the foregoing embodiments, the defined time interval is less than one minute. A preferred time interval for enabling the most reliable and accurate detection may, in particular, be at least 10 milliseconds.

[0058] According to an advantageous embodiment of the invention, reference environmental information is repeatedly detected in an event-based manner. This means that external factors, as events, initiate the detection of reference environmental information. This reduces the number of computational operations. According to an advantageous embodiment of the foregoing embodiments, the reference environmental information is repeatedly detected in an event-based manner such that changes in temperature and / or humidity trigger repeated detection of the reference environmental information. It has been found that if changes in temperature and / or humidity exceed a defined range, these effects as events are suitable for repeatedly performing new detections, making reliable detection possible.

[0059] According to an advantageous embodiment of the invention, if an object has changed its position relative to a vehicle or relative to a corresponding ultrasonic transducer, at least one object signal component detected by means of airborne acoustic signal information and / or object acoustic signal information in the reference environmental information generates a negative signal in the difference signal. This configuration provides more data that can be used to improve the accuracy and reliability of the detection results. In particular, the negative signal or object can be captured based on amplitude changes and / or phase changes. According to an advantageous embodiment of the foregoing embodiments, the negative signal is used inversely as a positive signal in the real-time environmental information for object tracking. The negative signal can be used to track the object based on feature data of the negative signal, as a positive signal relative to a previously known reference signal.

[0060] According to an advantageous embodiment of the invention, the computing unit is a dedicated circuit integrated into the ultrasonic sensor system. This enables reliable data processing within a cost-effective structural unit. An Application-Specific Integrated Circuit (ASIC) is an electronic circuit implemented in the form of an integrated circuit. Therefore, the functionality of an ASIC is no longer variable, but it has lower production costs and higher initial costs.

[0061] According to an advantageous embodiment of the invention, the proposed method for calculating sound compensation is also used in conjunction with an unhidden ultrasonic transducer to achieve improved object detection at close range by calculating the signal generated by the reverberation of the wall material for each measurement. The wall material is in the form of a membrane and can also be interpreted as structural acoustics.

[0062] According to an advantageous embodiment of the invention, the method is for calculating structural acoustic compensation, and the noise signal information is structural acoustic signal information. Structural acoustic signal information is a type of noise signal information, wherein structural sound detected by an ultrasonic sensor is considered structural acoustic signal information, which corresponds to vibrations of the wall material. This application is particularly suitable for ultrasonic transducers installed in a concealed manner, such as those mounted on vehicles.

[0063] According to an advantageous embodiment of the invention, the proposed method for calculating sound compensation is used in conjunction with concealed and / or unconcealed ultrasonic transducers to selectively block single or multiple unwanted airborne sound signals from the environment, such as those from trailer hitches or bicycle frames, and also to detect very subtle changes in the echo conditions of the environment, which can be complex in some cases, such as for detecting objects under a vehicle using ultrasonic transducers located in the underside area of ​​the vehicle, and / or for detecting any changes in structure sound patterns, such as due to changes in temperature, contamination, deformation, and / or damage. Damage can be, for example, a damaged glass pane. Here, at least one ultrasonic transducer can be attached to the glass pane and measure its structure sound. If the glass pane breaks, the detected structure sound signal changes, meaning that glass damage can be inferred. As a result, the noise signal that remains unchanged compared to the initial noise signal is considered the signal for an unbroken glass pane.

[0064] The invention will now be explained in more detail with reference to the accompanying drawings and based on preferred embodiments. Each feature shown may represent an aspect of the invention individually or in combination. Features of different exemplary embodiments may be transferred from one exemplary embodiment to another. Attached Figure Description

[0065] In the diagram:

[0066] Figure 1 A schematic diagram of an ultrasonic sensor system according to a preferred embodiment of the present invention is shown.

[0067] Figure 2 A car with an ultrasonic sensor system is shown.

[0068] Figure 3 An exemplary time signal curve and its difference generated according to this method are shown, as well as

[0069] Figure 4 A flowchart of the contact detection method is shown. Detailed Implementation

[0070] Figure 1 An ultrasonic sensor system 1, concealed and mounted, is shown. The ultrasonic sensor 5 is arranged on the wall material 2 of a vehicle and is used to detect noise signal information 3, particularly structural acoustic signal information 4, airborne acoustic signal information 7, and object acoustic signal information 7. See also... Figure 2 The ultrasonic sensor system can be integrated into a vehicle. As part of a specific, preferred exemplary embodiment, the noise signal information 3 will be assumed below to be structure acoustic signal information. The invention is not limited to ultrasonic sensors 5 installed in a concealed manner, although these sensors are used as examples in the exemplary embodiments to solve specific problems.

[0071] Hidden installation means that the ultrasonic sensor system 1 includes transmitters and / or receivers arranged in a way that is not visible from the outside of the vehicle.

[0072] The structural acoustic signal information and the airborne acoustic signal information 4 are processed in the computing unit 6.

[0073] exist Figure 1 No objects were detected. However, according to... Figure 3 In the case of time curves of c (the third image from the top) and 3d (the bottom image), such an object exists.

[0074] Figure 4 A flowchart illustrating contact detection for an ultrasonic sensor system 1 installed in a concealed or uncovered manner is shown schematically, particularly for a vehicle with a wall material 2. The method includes the following steps:

[0075] Following the steps of reference number "100", ultrasonic sensor 5 of ultrasonic sensor system 1 is used to detect reference environmental information. The reference environmental information includes time curves of signals with noise signal information 3 and airborne sound signal information 4 related to the wall material 2.

[0076] Specifically, by means of an ultrasonic transducer installed in a concealed manner, the characteristic structural acoustic signal 100 is excited and detected in a defined manner, and the system response is recorded in the time domain for later use as a reference signal or for generating such a reference signal.

[0077] Store the reference environment information according to the steps of reference number "200".

[0078] Following the steps of reference number "300", ultrasonic sensor 5 is used to detect real-time environmental information. The real-time environmental information includes a time profile of the signal, which contains noise signal information 3 and airborne sound signal information 4 related to the wall material 2, as well as object sound signal information 7 related to the object in contact with the wall material 2.

[0079] Based on the steps of reference number "400", the calculation unit 6 is used to form the difference signal between the environmental information of the reference environmental information and the real-time environmental information.

[0080] Further steps include applying methods to interpret the difference signal.

[0081] Specifically, the structure-sound signal is compensated by calculation through the difference between these corresponding signals and the reference signal in the time domain. As long as the structure-sound mode remains unchanged, the difference signal will not show any significant signal deflection. In the case of contact, changes in the structure-sound mode occur due to associated material stress and deformation, and / or due to associated airborne and structural sound, and / or particularly due to the mechanical damping of related changes in the vehicle shell bearing the structure-sound. This results in signal deflection in the difference signal.

[0082] According to Figure 1 In an advantageous embodiment, the computing unit 6 is a dedicated circuit integrated into the ultrasonic sensor system 1.

[0083] Figure 3 (Top image) illustrates the transmission and reception of signals in a concealed ultrasonic sensor system 1 or a concealed ultrasonic sensor 5 according to a preferred embodiment of the present invention. No objects, such as a hand placed on a vehicle body, are present in the detection area, so that the airborne acoustic signal information 4 or the object acoustic signal information 7 does not cause signal deflection. Because the ultrasonic sensor 5 is concealed, it detects noise or structural acoustic signal information 3. Therefore, reference environmental information is detected in the absence of objects.

[0084] Figure 3 (The second image from the top) illustrates the difference signal between the reference and real-time environmental information in a schematically simplified manner, with no objects positioned in the detection area. Therefore, if no contact is detected, there is complete compensation between the reference and real-time environmental information.

[0085] Figure 3 (The third image from the top) illustrates the transmission and reception of signals in a concealed ultrasonic sensor system 1 or a concealed ultrasonic sensor 5 according to a preferred embodiment of the present invention. In this case, an object is arranged in the detection area, such as a hand in contact with the wall material 2. As a result, signal deflection can be recorded for airborne acoustic signal information 4 and object acoustic signal information 7. The airborne acoustic signal information 4 and object acoustic signal information 7 are mixed. Because the ultrasonic sensor 5 is concealed, it also detects noise or structural acoustic signal information 3. However, these are superimposed, meaning that the object cannot be identified solely by this detection. In other words, the signal from the object is overridden by the signal from the structural sound or from the wall material 2.

[0086] Figure 3 (Bottom image) illustrates the difference signal between the environmental information of the reference environment and the real-time environment in a schematically simplified manner. Here, airborne acoustic signal information 4 and object acoustic signal information 7 can also be mixed. Signal contour features of the object are generated, allowing identification of which object is involved, for example, based on features of the signal envelope. In other words, when the difference is formed, it can be recognized that there is incomplete compensation between the reference environment information and the real-time environment information.

[0087] If a reference measurement is performed while the object is within the detection area, the object becomes visible in the difference signal once it changes its position relative to the ultrasonic transducer. In this case, it is sufficient if the object changes its position relative to the ultrasonic transducer even within the sub-millimeter range.

[0088] In other words, in addition to contacts that produce structured sound, contacts that do not produce either airborne or structured sound can also be detected. Static contacts can also be detected. In principle, large-area and point-like contacts can be detected.

[0089] The frequency at which the reference signal is generated can vary considerably. For example, each measurement can serve as a reference for the next measurement. On the other hand, only every 100 measurements can serve as a reference. Furthermore, a reference can be formed from multiple measurements.

[0090] Because even very small changes in the structure-sound pattern can lead to incomplete compensation when differences are formed, even relatively light contact can be detected. The structure-sound pattern is highly sensitive, particularly to changes in mechanical damping, so that, for example, even a slight touch of a hand on a structural area carrying the structure-sound can cause a significant signal deflection in the difference signal.

[0091] The generation of airborne ultrasound is also closely related to the excitation of structure sound. However, the signal deflection in the difference signal caused by changes in structure sound is usually significantly different in their curves from the signal deflection caused by changes in airborne acoustic echoes.

[0092] The method according to the invention, in combination with other methods known from the prior art for contact detection, particularly those based on the operating principles mentioned at the beginning—detecting changes in the acoustic spectrum of characteristic structures, detecting structural acoustics using structural acoustic sensors or ultrasonic sensors, or detecting changes in mechanical stress by means of piezoelectric layers—can use the same ultrasonic transducer.

[0093] If the materials of the vehicle, particularly the vehicle body, allow for sufficient propagation of structural sound, especially in the case of metals, hard plastics, and glass, then contact detection methods can be used. Therefore, all areas of the vehicle body, especially the following configurations, facilitate the application of this method: integrating at least one concealed ultrasonic transducer in each door, at least one concealed ultrasonic transducer in the trunk lid, at least one concealed ultrasonic transducer in the sliding roof, at least one concealed ultrasonic transducer in the fuel filler cap, or at least one concealed ultrasonic transducer in the hood.

[0094] Another possibility is its integration with keyless entry systems, allowing for contact-based identification of which door or barrier will be opened, for example... Figure 2 As shown. To implement this method, if appropriate, a concealed ultrasonic transducer already present in the vehicle can be used for normal environmental monitoring or object detection. Therefore, conversely, an ultrasonic transducer installed concealed for contact detection can also be used simultaneously for environmental monitoring or object detection, or as a proximity sensor.

[0095] According to an advantageous embodiment of the invention, the wall material 2 of the vehicle has a material thickness of at least 0.1 mm. According to one embodiment, it is also preferred that the wall material 2 of the vehicle has a material thickness of at most 3.0 mm. Figure 3 One of the signal curves shown, for example in the third image, exemplarily illustrates the structure-sound within this range.

[0096] According to an advantageous embodiment of the invention, the difference signal is smoothed and / or filtered.

[0097] According to an advantageous embodiment of the invention, the frequency of the ultrasonic sensor 5 is at least 40 kHz to 80 kHz. Ultrasonic detection occurring at such a frequency generates an audio signal, such as... Figure 3 An example is shown in the signal curve.

[0098] According to an advantageous embodiment of the invention, a difference signal between each piece of environmental information is formed based on the original data, the envelope and / or another filtered received signal, such as the correlation with the transmitted signal of the ultrasonic sensor 5. Figure 3The envelope is illustrated using a symbolic example. This means that ultrasonic signals are represented and processed through an envelope.

[0099] According to an advantageous embodiment of the invention, reference environment information is repeatedly detected at defined time intervals.

[0100] According to an advantageous embodiment of the foregoing embodiments, the defined time interval is less than one minute, particularly at least 10 milliseconds.

[0101] According to an advantageous embodiment of the invention, reference environment information is repeatedly detected in an event-based manner.

[0102] According to an advantageous embodiment of the foregoing embodiments, reference environmental information is repeatedly detected in an event-based manner, such that temperature changes and / or humidity changes trigger repeated detection of the reference environmental information.

[0103] According to an advantageous embodiment of the invention, if an object has changed its position relative to the vehicle or relative to the corresponding ultrasonic transducer, the signal component of at least one object detected by means of the airborne acoustic signal information 4 in the reference environmental information generates a negative signal in the difference signal.

[0104] According to an advantageous embodiment of the foregoing embodiments, the negative signal is reversed and used as a positive signal in real-time environmental information for object tracking.

[0105] List of reference numerals

[0106] 1. Ultrasonic sensor system

[0107] 2. Vehicle wall materials

[0108] 3. Noise signal information

[0109] 4. Airborne acoustic signal information

[0110] 5. Ultrasonic Sensor

[0111] 6. Calculation Unit

[0112] 7. Object acoustic signal information

[0113] 100 Testing Reference Environment Information

[0114] 200 Storage Reference Environment Information

[0115] 300 Real-time Environmental Information Detection

[0116] 400 generates differential signals between various environmental information items.

Claims

1. A method for contact detection of an ultrasonic sensor system (1) installed in a concealed or uncovered manner, for a vehicle having a wall material (2), wherein, The ultrasonic sensor (5) of the ultrasonic sensor system (1) is a distance sensor, and the method has the following steps: - Ultrasonic sensor (5) of ultrasonic sensor system (1) detects reference environmental information (100). - Store reference environment information (200); - Real-time environmental information (300) is detected using an ultrasonic sensor (5), wherein the detection of reference environmental information and real-time environmental information includes: the generation and emission of ultrasonic waves, and subsequent measurement of vibrations using the ultrasonic sensor; and - The computing unit (6) uses reference environmental information and real-time environmental information to form a difference signal (400) between each piece of environmental information, wherein the difference signal (400) between each piece of environmental information is formed based on the original data, envelope and / or correlation with the emitted signal of the ultrasonic sensor (5); and Based on the difference signal, the contact with the vehicle's outer wall is detected; in, The ultrasonic sensor system (1) is installed in a concealed manner; and The detection of reference environmental information and real-time environmental information also includes wall material excitation; The reference environmental information includes a time curve of the signal, which has: noise signal information (3) and / or airborne sound signal information (4) related to the wall material (2); The real-time environmental information includes a time curve of a signal having: noise signal information (3) related to the wall material (2) and / or airborne sound signal information (4) and / or object sound signal information (7) related to an object in contact with the wall material (2).

2. The method as described in claim 1, wherein, The wall material (2) is the wall material of the vehicle and has a material thickness in the range of at least 0.1 mm and at most 3.0 mm.

3. The method as described in claim 1, wherein, The difference signal is smoothed and / or filtered.

4. The method of claim 1, wherein, The frequency of the ultrasonic sensor (5) is at least 40 kHz to 80 kHz.

5. The method of claim 1, wherein, Repeatedly detect reference environment information (100) at defined time intervals.

6. The method of claim 1, wherein, Repeatedly detect reference environment information (100) in an event-based manner.

7. The method of claim 1, wherein, If an object changes its position based on the reference environment information, then at least one object signal component detected in the reference environment information by means of the airborne acoustic signal information (4) and / or the object acoustic signal information (7) generates a negative signal in the difference signal.

8. The method of claim 1, wherein, The computing unit (6) is a dedicated circuit integrated into the ultrasonic sensor system (1).

9. A system for contact detection of an ultrasonic sensor system (1) installed in a concealed or unconcealed manner, for a vehicle having a wall material (2), the system being configured to perform the method according to any one of claims 1 to 8, the system having: An ultrasonic sensor system (1) having one or more ultrasonic sensors (5) is configured as follows: Detect reference environmental information, wherein the reference environmental information includes the time curve of the signal, which has: noise signal information (3) related to the wall material (2) and / or airborne sound signal information (4). A storage device configured to store reference environment information; One or more of the ultrasonic sensors (5) are configured as follows: Detecting real-time environmental information, wherein the real-time environmental information includes the time curve of a signal having: noise signal information (3) related to the wall material (2) and / or airborne sound signal information (4) and / or object sound signal information (7) related to an object in contact with the wall material (2); and The computing unit (6) is configured to form a difference signal between the environmental information of the reference environment information and the environmental information of the real-time environment information.

10. A vehicle having a system for contact detection of an ultrasonic sensor system (1) installed in a concealed or unconcealed manner as described in claim 9.

11. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method as described in any one of claims 1 to 8.

12. A data carrier signal for transmitting a computer program product as described in claim 11.

13. A computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the method as claimed in any one of claims 1 to 8.

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