Ultrasonic sensor device for a motor vehicle, motor vehicle and process

Abstract

Ultrasonic sensor device (1) for a motor vehicle, comprising an ultrasonic membrane (3), an actuator (4) for moving the ultrasonic membrane (3) and a control device (7) for controlling the actuator (4), wherein the ultrasonic sensor device (1) has a storage device (9) in which a production date of the ultrasonic sensor device (1) is stored, the control device (7) is designed to determine the age of the ultrasonic sensor device (1) based on the stored production date, and the control device (7) is designed to determine an operating state of the ultrasound membrane (3) and / or the actuator (4) at least on the basis of the specified age, characterized by the fact that the control device (7) is designed to adjust the power required to operate the actuator (4) depending on the specific operating state of the ultrasonic membrane (3) and / or the actuator (4).

Description

[0001] The present invention relates to an ultrasonic sensor device for a motor vehicle, comprising an ultrasonic membrane, an actuator for moving the ultrasonic membrane, and a control unit for controlling the actuator. Furthermore, the present invention relates to a motor vehicle with at least one such ultrasonic sensor device. Finally, the present invention relates to a method for operating an ultrasonic sensor device for a motor vehicle.

[0002] Modern motor vehicles incorporate a multitude of mechatronic systems. Such mechatronic systems typically comprise a mechanical component, an electronic component, and an information technology component. This study focuses particularly on mechatronic systems that include a mechanical component, an actuator for moving the mechanical component, and a control unit for activating the actuator.

[0003] Such a mechatronic system in a motor vehicle could, for example, be an ultrasonic sensor or ultrasonic sensor device. These ultrasonic sensors are used, for instance, to detect objects in the vicinity of the vehicle and, in particular, to determine the distance to an object. Such an ultrasonic sensor typically has an ultrasonic diaphragm as its mechanical component. This ultrasonic diaphragm can be moved or set into mechanical vibration. For this purpose, the ultrasonic sensor has an actuator, which can, for example, be a piezoelectric actuator. The ultrasonic sensor can be controlled by a corresponding control unit, which can, for example, be the vehicle's control unit, via an electrical signal.

[0004] Ultrasonic sensor devices age over time. In particular, the ultrasonic diaphragm, as a mechanical component that is moved or subjected to mechanical vibrations, changes its operating characteristics over time due to wear and tear. For example, the detection performance of ultrasonic sensors deteriorates with their lifespan.

[0005] German patent DE 10 2012 200 592 A1 discloses a method and a device for determining the state of a sensor, which may, for example, be an ultrasonic sensor. In this prior art, at least one aging influence, such as temperature or the number of switching cycles, is detected during operation and stored as aging information in an electronic memory. Based on a predefined relationship between the aging influence and the sensor state, the current state of the sensor is derived in order to, for example, computationally correct a sensor characteristic curve for determining the measured value.

[0006] The object of the present invention is to provide a solution for how an ultrasonic sensor device of the type mentioned above can be operated more reliably.

[0007] This problem is solved according to the invention by an ultrasonic sensor device, by a motor vehicle, and by a method with the features according to the respective independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description, and the figures.

[0008] An ultrasonic sensor device according to the invention for a motor vehicle comprises an ultrasonic membrane, an actuator for moving the ultrasonic membrane, and a control unit for controlling the actuator. The ultrasonic sensor device includes a storage device in which a production date of the ultrasonic sensor device is stored, and the control unit is designed to determine the age of the ultrasonic sensor device based on the stored production date.

[0009] The ultrasonic sensor device is a mechatronic system. This mechatronic system includes a mechanical component in the form of the ultrasonic membrane. Furthermore, the mechatronic system includes a corresponding actuator that serves to move or vibrate the mechanical component. The actuator can be controlled, in particular, by an electrical signal. The actuator can therefore be designed as an electromechanical transducer. The ultrasonic sensor device also includes a control unit, which can, for example, be a vehicle control unit. The control unit can output electrical signals to control the actuator.

[0010] The present invention is based on the finding that the age of an ultrasonic sensor device can be easily determined by storing a production date of the ultrasonic sensor device in its memory unit. This date can then be read by the control unit, thus determining the age or remaining lifespan of the ultrasonic sensor device. The production date of the ultrasonic sensor device can be stored in the memory unit after its manufacture. The production date can then be easily read from the memory unit by the control unit via a suitable data connection. This allows the age of the ultrasonic sensor device to be determined with minimal effort.

[0011] Preferably, the control unit is designed to determine the current date and the age of the ultrasonic sensor device by comparing this date with the stored production date. The control unit may include a suitable microcontroller or digital signal processor. Furthermore, the control unit may include a clock or timer for determining the current date. By comparing the current date with the production date read from the ultrasonic sensor device's memory, the age or service life of the ultrasonic sensor device can be determined simply and reliably.

[0012] Furthermore, it has proven advantageous for the ultrasonic sensor device to include a temperature sensing device for continuously monitoring the temperature of the ultrasonic membrane and / or the actuator. The temperature sensing device can, for example, include a suitable temperature sensor located in close proximity to the ultrasonic membrane or the actuator. This allows for easy determination of the temperature stress on the ultrasonic sensor. For instance, temperature fluctuations to which the ultrasonic membrane is exposed can be recorded. In this context, it can also be provided that a temperature threshold is set and the frequency with which this threshold is exceeded is monitored. In this way, external influences or...Environmental influences on the ultrasonic sensor device and in particular the mechanical component, i.e. the ultrasonic membrane, are monitored.

[0013] In another embodiment, the ultrasonic sensor device includes a detection unit for recording the number of activation cycles of the actuator. In other words, the detection unit can determine how often the actuator has been switched on or activated. This allows the number of times the ultrasonic sensor device has been operated to be determined. Based on the number of activation cycles, the stress on the ultrasonic sensor device, and in particular on the ultrasonic membrane or the actuator, can be easily inferred.

[0014] In a further embodiment, the control unit is designed to determine the operating state of the ultrasonic membrane and / or the actuator based on its age, the measured temperature, and / or the number of activation cycles. This allows for a simple determination of the extent to which the ultrasonic sensor device is subject to aging or how much stress the sensor has already been subjected to. The age of the sensor can be taken into account for this purpose. Alternatively or additionally, the temperature fluctuations that have already affected the ultrasonic sensor device or the membrane can be considered. Furthermore, the maximum and / or minimum temperatures to which the ultrasonic sensor device has been exposed can be taken into account. Finally, the number of activation cycles or switching-on cycles can be considered.Thus, the current operating condition can be determined based on the age, external influences, and operating time.

[0015] In one embodiment, the control unit is designed to control the actuator depending on the specific operating state of the ultrasonic membrane and / or the actuator. Based on the determined operating state, it is possible to deduce the extent to which the ultrasonic sensor device has already aged or been subjected to stress. This can be taken into account when controlling the ultrasonic sensor device and, in particular, when controlling the actuator. Thus, compensation for aging or stress can be achieved.

[0016] According to the invention, the control device is designed to adjust the power output for operating the actuator depending on the specific operating state of the ultrasonic membrane and / or the actuator. In particular, the electrical power with which the actuator is operated can be increased. In this way, the aging effects of the ultrasonic sensor device and especially its mechanical components can be compensated for.

[0017] Preferably, the control unit is designed to adjust the frequency for operating the actuator depending on the specific operating state of the ultrasonic membrane and / or the actuator. This aspect proves particularly advantageous because the ultrasonic membrane is typically operated at its resonant frequency. Due to aging or operation, the resonant frequency of the ultrasonic membrane can change slightly. By adjusting the frequency at which the actuator is driven, this drift in the resonant frequency can be compensated for. Thus, the ultrasonic sensor device can be operated energy-efficiently.

[0018] Preferably, the ultrasonic sensor device includes a measuring device for measuring the movement of the ultrasonic membrane, and the control device is designed to control the measuring device depending on the specific operating state of the ultrasonic membrane and / or the actuator. The measuring device can include a suitable sensor with which the movement or mechanical vibration of the membrane can be detected. When measuring the movement of the ultrasonic membrane or evaluating the signal, the operating state can be taken into account, including the aging and / or stress on the ultrasonic membrane. In this way, the movement of the ultrasonic membrane can be reliably detected.

[0019] Preferably, the control unit is designed to adjust the amplification of a received signal from the measuring device depending on the specific operating state of the ultrasonic membrane and / or the actuator. This takes into account the fact that the ultrasonic membrane wears down over time. Therefore, lower signal amplitudes can be achieved when measuring the movement or vibration of the ultrasonic membrane. By appropriately amplifying these measurement signals, the movement of the ultrasonic membrane can be reliably detected.

[0020] Preferably, the actuator comprises a piezoelectric element. An actuator that includes or is formed by a piezoelectric element can be manufactured simply and cost-effectively. Furthermore, the piezoelectric element can be used to detect the mechanical vibration of the ultrasonic membrane. Thus, the actuator can also be used as the measuring device.

[0021] The motor vehicle according to the invention comprises at least one ultrasonic sensor device according to the invention. The motor vehicle is, in particular, designed as a passenger car.

[0022] The method according to the invention serves to operate an ultrasonic sensor device for a motor vehicle. An actuator is controlled by a control unit, and an ultrasonic membrane is moved by the actuator. Furthermore, it is provided that the age of the ultrasonic sensor device is determined by the control unit based on a production date stored in a memory unit of the ultrasonic sensor device.

[0023] The preferred embodiments and their advantages presented with reference to the ultrasonic sensor device according to the invention apply accordingly to the motor vehicle according to the invention and to the method according to the invention.

[0024] Further features of the invention will become apparent from the claims, the figures, and the description of the figures. All features and combinations of features mentioned above in the description, as well as those subsequently mentioned in the description of the figures and / or shown in the figures alone, are usable not only in the combinations specified, but also in other combinations or individually.

[0025] The invention will now be explained in more detail with reference to a preferred embodiment and the accompanying drawings.

[0026] They show: Fig. 1 in schematic representation an ultrasonic sensor device according to an embodiment of the invention; and Fig. 2 a flowchart of a process according to an embodiment of the invention.

[0027] Fig. Figure 1 shows a highly simplified representation of an ultrasonic sensor device 1 for a motor vehicle. The ultrasonic sensor device 1 represents a mechatronic system 1. This mechatronic system comprises a mechanical component 2, which in this case is designed as an ultrasonic membrane 3. The ultrasonic membrane 3 can, for example, be made of aluminum. The ultrasonic membrane 3 can, in particular, have a resonant frequency between 40 kHz and 60 kHz. Furthermore, the ultrasonic sensor device 1 comprises an actuator 4 with which the mechanical component 2, or the ultrasonic membrane 3, can be moved. In particular, the actuator 4 is designed to set the ultrasonic membrane 3 into mechanical vibrations. The actuator 4 is designed as an electromechanical transducer, that is, it can convert an electrical input signal into a mechanical movement. The actuator 4 is preferably connected to the mechanical component 2.In the present embodiment, the actuator 4 comprises a piezoelectric element 5. The ultrasonic membrane 3 and the actuator 4 are arranged at least partially in a common housing 6.

[0028] Furthermore, the ultrasonic sensor device 1 includes a control unit 7. The control unit 7 can, for example, be a control unit of the motor vehicle. The control unit 7 can have a microcontroller and / or a digital signal processor. The control unit 7 is connected to the ultrasonic sensor device 1 via an electrical connection or a data line. This is illustrated by line 8 in this example. In particular, the control unit 7 is electrically connected to the actuator 4. The control unit 7 can output a corresponding electrical signal to control the actuator 4. In the present embodiment, the control unit 7 is provided as a separate component. However, it can also be provided that the control unit 7 is arranged in the housing 6.

[0029] Furthermore, the ultrasonic sensor device 1 includes a storage device 9. The storage device 9 is specifically designed as non-volatile memory. The production date of the ultrasonic sensor device 1 is stored in the storage device 9. For this purpose, the production date can be stored in the storage device 9 after the ultrasonic sensor device 1 has been manufactured or at the end of the manufacturing process. The ultrasonic sensor device 1 also includes a temperature sensing device 10, with which the temperature of the ultrasonic sensor device 1, and in particular of the mechanical component 2, can be detected. The temperature sensing device 10 can include a corresponding temperature sensor for this purpose. Finally, the ultrasonic sensor device 1 includes a detection device 11, with which a number of activation events of the actuator 4 can be detected.In other words, the detection device 11 can record how often the actuator 4 was switched on. For this purpose, it can be determined, for example, how often a corresponding control signal was transmitted from the control unit 7 to the actuator 4.

[0030] In the present embodiment, the piezoelectric element 5 serves not only as an actuator 4 but also as a measuring device 12. The measuring device 12 can detect a mechanical movement or a mechanical vibration of the mechanical component 2 or the ultrasonic membrane 3.

[0031] For example, the piezoelectric element 5 can first be subjected to an electrical voltage, causing the mechanical component 2 or the ultrasound membrane 3 to vibrate. After a predetermined decay period, a mechanical vibration of the mechanical component 2 or the ultrasound membrane 3 can be detected. This vibration could, for example, originate from an echo of an ultrasound signal reflected by an object. The piezoelectric element 5 converts the mechanical movement of the mechanical component 2 into an electrical signal, which can then be evaluated by the control unit 7.

[0032] When the ultrasonic sensor device 1 is operated, performance losses occur over time due to the aging of the ultrasonic sensor device 1 and, in particular, the mechanical component 2 or the ultrasonic membrane 3. The ultrasonic membrane 3, which is subjected to mechanical vibrations, can wear out over time. Likewise, the retaining elements that hold the ultrasonic membrane 3 can wear out over time. To determine the aging or stress on the ultrasonic sensor device 1, its age is now determined. For this purpose, the production date is read from the storage device 9 using the control unit 7. The control unit 7 can then determine the current date, for example, using data from a clock generator.Furthermore, the control unit 7 is designed to determine the age of the ultrasonic sensor device 1 and, in particular, the ultrasonic membrane 3 by comparing the current date with the read-out production date.

[0033] The present purpose is to determine the operating state of the ultrasonic sensor device 1, which describes the extent to which the ultrasonic sensor device 1 has already aged or been subjected to stress. In addition to the age of the ultrasonic sensor device 1, the environmental influences that have acted on it over time can be determined for this purpose. To this end, the control unit 7 can read the data from the temperature detection device 10. For example, it can be determined how often a predetermined temperature threshold, which could be 90°C, has been exceeded. Furthermore, the temperature fluctuations to which the ultrasonic sensor device 1 has been exposed can be taken into account. Another aspect that can be considered for determining the operating state of the ultrasonic sensor device 1 is the number of switching cycles.For this purpose, the control unit 7 can read the data from the recording unit 11. This makes it possible to determine how often the actuator 4 has already been activated.

[0034] To determine the operating status, a counter can be provided that increments depending on the age of the ultrasonic sensor device 1. The counter can be incremented if there is a significant temperature influence, for example, if a temperature threshold is exceeded and / or fallen below. The counter can also be incremented if the number of activation cycles exceeds a certain threshold. Conversely, for example, if the actuator 4 has only been activated infrequently, the counter value can be decremented. This can also be done, for instance, if the temperature load on the ultrasonic sensor device 1 is within a predetermined range where only a minor influence on the ultrasonic sensor device 1 is expected.

[0035] To compensate for the aging or stress on the ultrasonic sensor device 1, the control of the actuator 4 can be adjusted accordingly by the control unit 7. When the operating state of the ultrasonic sensor device 1 reaches a predetermined threshold, the electrical power used to control the actuator 4 can be increased. Furthermore, the frequency of the electrical signal used to control the actuator 4 can be adjusted. Particularly in the case of ultrasonic sensors, which are typically operated at their resonant frequency, the resonant frequency of the mechanical component 2 or the ultrasonic diaphragm can decrease over time due to mechanical wear. This typically slight shift in the resonant frequency can be compensated for by adjusting the frequency of the electrical control signal transmitted from the control unit 7 to the actuator 4.

[0036] Furthermore, the aging or stress on the ultrasonic sensor device 1 can be taken into account when reading the measurement signals. For this purpose, for example, a measurement signal or a received signal acquired by the measuring device 12 can be increased from a predetermined operating state. In this way, the ultrasonic sensor device 1 can be operated reliably and its aging can be compensated for.

[0037] Fig.Figure 2 shows a schematic diagram of a process for operating the ultrasonic sensor device 1. In a first step S1, the ultrasonic sensor device 1 is started. This can occur, for example, when the ignition of the vehicle is activated. In a further step S2, sensor data is read out. Here, the production date can be read from the storage device 9 using the control unit 7. Alternatively or additionally, the data from the temperature detection device 10 and the data from the detection device 11 can be read out. Based on this data, the service life or operating state of the ultrasonic sensor device 1 or the mechatronic system is calculated in a step S3.

[0038] In step S4, the control of actuator 4 by means of control unit 7 or the evaluation of the measurement signals transmitted from measuring device 12 to control unit 7 is adjusted. Predefined aging data, provided in step S5, can also be taken into account. The data from temperature sensing device 10 and sensing device 11 can also be considered to determine the predefined aging data. In step S6, the ultrasonic sensor device 1 can be reprogrammed accordingly. This means that the operating parameters for controlling actuator 4 by means of control unit 7 and for evaluating the measurement data transmitted from measuring device 12 to control unit 7 can be stored in control unit 7. Finally, in step S7, an ultrasonic sensor device 1 is created whose performance and / or...exhibits the performance of a new part.

[0039] The method for operating the ultrasonic sensor device 1 can, in principle, be applied to all mechatronic systems that have a moving mechanical component which is therefore subject to wear. This allows the aging of the mechatronic system to be reliably compensated.

Claims

[1] Ultrasonic sensor device (1) for a motor vehicle, comprising an ultrasonic membrane (3), an actuator (4) for moving the ultrasonic membrane (3) and a control device (7) for controlling the actuator (4), wherein the ultrasonic sensor device (1) has a storage device (9) in which a production date of the ultrasonic sensor device (1) is stored, the control device (7) is designed to determine the age of the ultrasonic sensor device (1) based on the stored production date, and the control device (7) is designed to determine an operating state of the ultrasound membrane (3) and / or the actuator (4) at least on the basis of the specified age, characterized by , that the control device (7) is designed to adjust the power required to operate the actuator (4) depending on the specific operating state of the ultrasonic membrane (3) and / or the actuator (4). [2] Ultrasonic sensor device (1) according to claim 1, characterized by , that the control device (7) is designed to determine a current date and to determine the age of the ultrasonic sensor device (1) by comparing the determined current date with the stored production date. [3] Ultrasonic sensor device (1) according to claim 1 or 2, characterized by , that the ultrasonic sensor device (1) has a temperature sensing device (10) for continuously sensing a temperature of the ultrasonic membrane (3) and / or the actuator (4). [4] Ultrasonic sensor device (1) according to any one of the preceding claims, characterized by , that the ultrasonic sensor device (1) comprises a detection device (11) for detecting a number of activation processes of the actuator (4). [5] Ultrasonic sensor device (1) according to claim 3 or 4, characterized by, that the control device (7) is designed to determine an operating state of the ultrasonic membrane (3) and / or the actuator (4) based on the detected temperature and / or the detected number of activation events. [6] Ultrasonic sensor device (1) according to claim 5, characterized by , that the control device (7) is designed to control the actuator (4) depending on the specific operating state of the ultrasound membrane (3) and / or the actuator (4). [7] Ultrasonic sensor device (1) according to one of claims 5 to 6, characterized by , that the control device (7) is designed to adapt a frequency for operating the actuator (4) depending on the specific operating state of the ultrasonic membrane (3) and / or the actuator (4). [8] Ultrasonic sensor device (1) according to any one of claims 5 to 7, characterized by, that the ultrasonic sensor device (1) has a measuring device (12) for measuring the movement of the ultrasonic membrane (3) and the control device (7) is designed to control the measuring device (12) depending on the specific operating state of the ultrasonic membrane (3) and / or the actuator (4). [9] Ultrasonic sensor device (1) according to claim 8, characterized by , that the control device (7) is designed to adjust the amplification of a received signal from the measuring device (12) depending on the specific operating state of the ultrasonic membrane (3) and / or the actuator (4). [10] Ultrasonic sensor device (1) according to any one of the preceding claims, characterized by , that the actuator (4) comprises a piezoelectric element (5). [11] Motor vehicle with at least one ultrasonic sensor device (1) according to one of the preceding claims. [12] Method for operating an ultrasonic sensor device (1) for a motor vehicle, in which an actuator (4) is controlled by means of a control device (7) and an ultrasonic membrane (3) is moved by means of the actuator (4), by means of the control device (7) the age of the ultrasonic sensor device (1) is determined on the basis of a production date which is stored in a storage device (9) of the ultrasonic sensor device (1) (S3), and by means of the control device (7) an operating state of the ultrasound membrane (3) and / or the actuator (4) is determined at least on the basis of the specified age, characterized by , that The control unit (7) is used to adjust the power required to operate the actuator (4) depending on the specific operating state of the ultrasound membrane (3) and / or the actuator (4).

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