System and method of operation for controlling vehicle ultrasonic sensors

Abstract

This invention discloses a system and operating method for controlling ultrasonic sensors in a vehicle. The system includes: an ultrasonic sensor comprising an ultrasonic transducer that generates ultrasonic waves and a control module that controls the drive frequency of the ultrasonic waves emitted from the ultrasonic transducer, wherein multiple ultrasonic sensors are mounted externally to the vehicle; and a control unit that sets multiple drive frequencies with guard bands formed therebetween, and controls the control module to cause the multiple ultrasonic sensors to emit and receive ultrasonic waves having different drive frequencies from each other.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0034873 and Korean Patent Application No. 10-2021-0034874, filed on March 17, 2021, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] This invention relates to a technique for controlling a vehicle's ultrasonic sensor using multiple frequencies. Background Technology

[0004] Typically, collision avoidance devices developed to prevent car accidents use ultrasound, radio waves, or images to measure the distance to adjacent vehicles in a non-contact manner, and prevent accidents by automatically braking or warning the driver when the distance between the main vehicle and the adjacent vehicle decreases to or below a safe distance.

[0005] Such a device takes into account the speed of the main vehicle, the moving speed and distance to the adjacent vehicle or object, the braking distance of the vehicle, the human response time, etc., presets a safe distance suitable for various situations, analyzes the situation when the vehicle is being driven, and warns the driver or automatically brakes when the distance between the main vehicle and the vehicle in front decreases to or below the preset safe distance.

[0006] Specifically, the ultrasonic sensor 100 is used to assist driving when the vehicle is in motion, but it is more commonly used to detect adjacent vehicles or objects around the vehicle while it is parked, and the use of the sensor has been greatly expanded from measuring parking distances to remote parking, emergency braking during parking, etc.

[0007] Therefore, installing multiple ultrasonic sensors in a vehicle and using a single frequency based on the vehicle's frequency sensitivity / characteristics leads to problems with reduced data response and update time.

[0008] The above-described technical background is only for better understanding of the background of the present invention and should not be regarded as an admission that they belong to conventional technology known to those skilled in the art. Summary of the Invention

[0009] The present invention is proposed to solve the above-mentioned problems and aims to drive multiple ultrasonic sensors installed in a vehicle at multiple frequencies.

[0010] An ultrasonic sensor control system for a vehicle according to the present application includes: ultrasonic sensors including an ultrasonic transducer generating ultrasonic waves and a control module controlling a drive frequency of the ultrasonic waves emitted from the ultrasonic transducer, wherein a plurality of ultrasonic sensors are installed outside the vehicle; and a control unit setting a plurality of drive frequencies with a guard band formed therebetween, and controlling the control module so that the plurality of ultrasonic sensors emit and receive ultrasonic waves having different drive frequencies from each other.

[0011] The control unit can group adjacent ultrasonic sensors among the plurality of ultrasonic sensors, and set the drive frequencies of the plurality of grouped ultrasonic sensors to be different from each other.

[0012] The control module can include a filter having a cutoff frequency set to filter the received ultrasonic waves, and the control unit can set the guard band according to a characteristic of the filter.

[0013] The filter can include a band pass filter passing only frequencies within a preset frequency band width, and the control unit can set the guard band to a value greater than the frequency band width preset in the band pass filter.

[0014] The frequency band preset in the band pass filter can be preset to a frequency in a frequency band in which a voltage converted in the ultrasonic transducer is reduced by half.

[0015] The frequency band preset in the band pass filter can be preset by a Q factor and a center frequency of a frequency of the ultrasonic waves.

[0016] The filter can include a matched filter determining whether a received drive frequency is a valid frequency based on a common element between a preset reference frequency and the received drive frequency, and the control unit can set the guard band based on the preset reference frequency.

[0017] The control unit can select a plurality of frequencies at drive frequency points and set the plurality of frequencies.

[0018] The control unit can set the plurality of frequencies by frequency modulation.

[0019] The control unit can compensate for a sensitivity of the ultrasonic waves reflected from the target and received, and control the control module for sensing the target.

[0020] The control unit can set a reference sensitivity of a frequency of the received ultrasonic waves and increase or decrease the frequency of the ultrasonic waves reflected from the target and received to sense at the reference sensitivity.

[0021] The control unit can pre-map component characteristics and temperature of the ultrasonic sensor, predict sensor sensitivity at a certain frequency based on the pre-mapping, and convert the sensor sensitivity into a reference sensitivity for sensing.

[0022] The sensor diagnosis unit can diagnose the ultrasonic sensor and calculate a transfer function of the ultrasonic sensor, and the control unit can predict an element value of the ultrasonic sensor in the equivalent circuit based on the transfer function of the ultrasonic sensor calculated by the sensor diagnosis unit and convert the element value into the reference sensitivity for sensing.

[0023] The sensing unit can sense an external temperature or humidity through which the ultrasonic waves generated by the ultrasonic sensor are transmitted, and the control unit can calculate an attenuation coefficient of the ultrasonic waves in the air according to the temperature or humidity sensed by the sensing unit and convert the attenuation coefficient into the reference sensitivity for sensing.

[0024] The vehicle ultrasonic sensor control method according to the present application can include setting a plurality of driving frequencies at which a guard band is formed, controlling so that a plurality of ultrasonic sensors emit and receive ultrasonic waves having the set driving frequencies different from each other, and compensating for sensitivity of the ultrasonic waves reflected from a target and received for sensing the target.

[0025] The method can further include grouping adjacent ultrasonic sensors among the plurality of ultrasonic sensors before the driving frequencies are set, and in the controlling, the plurality of grouped ultrasonic sensors can be set to the driving frequencies different from each other.

[0026] The sensing of the target can include setting a reference sensitivity of a frequency of the received ultrasonic waves and increasing or decreasing the frequency of the ultrasonic waves reflected from the target and received to sense at the reference sensitivity.

[0027] The method can further include pre-mapping component characteristics and temperature of the ultrasonic sensor, and the sensing of the target can include predicting sensor sensitivity at a certain frequency based on the pre-mapping and converting the sensor sensitivity into the reference sensitivity for sensing.

[0028] The method can further include diagnosing the ultrasonic sensor and calculating a transfer function of the ultrasonic sensor, and the sensing of the target can include predicting an element value of the ultrasonic sensor in the equivalent circuit based on the transfer function of the ultrasonic sensor calculated by the sensor diagnosis unit and converting the element value into the reference sensitivity for sensing.

[0029] The method can further include sensing an external temperature or humidity through which the ultrasonic waves generated by the ultrasonic sensor are transmitted, and the sensing of the target can include calculating an attenuation coefficient of the ultrasonic waves in the air according to the sensed temperature or humidity and converting the attenuation coefficient into the reference sensitivity for sensing.

[0030] The vehicle ultrasonic sensor control system according to the present application drives a plurality of ultrasonic sensors provided in a vehicle using a plurality of frequencies, thereby allowing an effect of shortening an update time of sensing data from the ultrasonic sensors.

[0031] Further, grouping adjacent ultrasonic sensors of a vehicle and driving a plurality of grouped ultrasonic sensors at different frequencies from each other reduces the number of frequencies, such that an ultrasonic transducer having a relatively narrow frequency band is used, thereby allowing an effect of reducing costs to be achieved.

[0032] In addition, driving a plurality of ultrasonic sensors at a plurality of frequencies has an effect of shortening an update time of sensing data from the ultrasonic sensors, and using a plurality of frequencies allows an effect of accurately receiving sensing data by adjusting frequency sensitivity of received ultrasonic waves to be achieved.

[0033] Further, pre-mapping frequency sensitivity of each frequency characteristic, diagnosing an ultrasonic sensor to calculate a transfer function of the sensor, and sensing temperature or humidity of a medium through which an ultrasonic wave is transmitted to adjust the frequency sensitivity allow an effect of accurately receiving sensing data to be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 FIG. 1 is a block diagram illustrating a vehicle ultrasonic sensor control system according to an embodiment of the present application.

[0035] Figure 2 FIG. 2 is a perspective view illustrating a vehicle ultrasonic sensor according to an embodiment of the present application.

[0036] Figure 3 FIG. 3 is a graph illustrating a frequency characteristic of each driving frequency according to an embodiment of the present application.

[0037] Figure 4 FIG. 4 is a graph illustrating a frequency characteristic of a band pass filter.

[0038] Figure 5 FIG. 5 is a graph illustrating a frequency characteristic of a matched filter.

[0039] Figure 6 FIG. 6 is a view illustrating a mounting position of a vehicle ultrasonic sensor according to an embodiment of the present application.

[0040] Figure 7 FIG. 7 is a graph illustrating selected minimum / maximum frequency / sensitivity characteristic curves of main characteristic values of an ultrasonic sensor transducer obtained at three temperatures (-40 degrees, +25 degrees, +70 degrees), respectively.

[0041] Figure 8is a graph showing an adjustment result having a reference sensitivity according to a sensed ultrasonic frequency.

[0042] Figure 9 is a graph showing a transfer function and a phase curve of an ultrasonic sensor diagnosed by a sensor.

[0043] Figure 10 is a graph showing a change in an attenuation coefficient of an ultrasonic wave in air with respect to temperature / humidity under the same frequency / atmospheric pressure conditions.

[0044] Figure 11 is a flowchart of a vehicle ultrasonic sensor control method according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] The specific configuration or functional descriptions of the embodiments of the present application disclosed in the present specification or application are present by way of example only for the purpose of describing the embodiments according to the present application, and the embodiments according to the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments described in the present specification or application.

[0046] Since the embodiments of the present application can be modified in various ways and have various forms, specific embodiments will be shown in the accompanying drawings and described in the present specification or application. However, this is not intended to limit the embodiments according to the present inventive concept to specific forms, and is explained to include all modifications, equivalents, and alternatives included within the spirit and scope of the present application.

[0047] Terms such as first and / or second can be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, a first component can be referred to as a second component, and similarly, a second component can also be referred to as a first component without departing from the scope of the inventive concept.

[0048] When a component is referred to as being "connected" or "coupled" to another component, it can be directly connected or coupled to the other component, but it should be understood that other components can exist therebetween. On the other hand, when a component is referred to as being "directly connected" or "directly coupled" to another component, it should be understood that there are no intermediate components therebetween. Other expressions describing the relationship between components, such as "between" and "only between" or "adjacent to" and "directly adjacent to", should be interpreted in the same manner.

[0049] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, including in the claims "or" as used herein is inclusive or meant to be the term "and / or." Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and claims and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0050] Unless otherwise defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and claims and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0051] Hereinafter, the present application will be described in detail by describing preferred embodiments of a control system of a vehicle ultrasonic sensor 100 according to the present application with reference to the accompanying drawings. The same reference numbers will be used throughout the drawings to refer to the same components.

[0052] The control unit 200 according to the exemplary embodiment of the present application can be implemented by a processor (not shown) configured to perform the operations described below using an algorithm configured to control the operations of the components of the vehicle, or a non-volatile memory (not shown) configured to store data related to software commands for reproducing the algorithm and data stored in the memory. Here, the memory and the processor can be implemented as separate chips. Alternatively, the memory and the processor can be implemented as a single integrated chip. The processor can take the form of one or more processors.

[0053] Figure 1 is a block diagram illustrating a control system of a vehicle ultrasonic sensor 100 according to an embodiment of the present application; Figure 2 is a perspective view illustrating a vehicle ultrasonic sensor 100 according to an embodiment of the present application; Figure 3 is a graph illustrating a frequency characteristic of each drive frequency according to an embodiment of the present application; Figure 4 is a graph illustrating a frequency characteristic of a band pass filter 11; Figure 5 is a graph illustrating a frequency characteristic of a matched filter 11; and Figure 6 is a view illustrating a mounting position of a vehicle ultrasonic sensor 100 according to an embodiment of the present application.

[0054] Reference will be made to Figures 1 to 6 A preferred embodiment of a control system of a vehicle ultrasonic sensor 100 according to the present application will be described.

[0055] The ultrasonic transducer 20 used in the ultrasonic sensor 100 can be driven to emit and receive ultrasonic waves by attaching a piezoelectric element (oscillator) to an aluminum shell. In this case, a resonant point exists in the driving frequency band according to the frequency characteristics of the piezoelectric element, and the maximum sensitivity is sensed at the resonant point. Therefore, the conventional ultrasonic sensor 100 uses only one frequency.

[0056] However, because multiple ultrasonic sensors 100 are installed in the vehicle, using a single frequency requires sequentially driving multiple ultrasonic sensors 100 to avoid signal interference between sensors during measurement, which causes a delay in measurement and data updates.

[0057] To solve the above problems, the control system of the vehicle ultrasonic sensor 100 according to the present invention includes: an ultrasonic sensor 100, the ultrasonic sensor 100 including an ultrasonic transducer 20 that generates ultrasonic waves and a control module 10 that controls the drive frequency of the ultrasonic waves emitted from the ultrasonic transducer 20, wherein a plurality of ultrasonic sensors are mounted on the exterior of the vehicle; and a control unit 200 that sets a plurality of drive frequencies, a guard band located between the plurality of drive frequencies, and the control unit 200 controls the control module 10 to cause the plurality of ultrasonic sensors 100 to emit and receive ultrasonic waves having drive frequencies different from each other.

[0058] like Figure 1 and Figure 2 As shown, in the same configuration as a conventional ultrasonic sensor 100, the ultrasonic sensor 100 may include an ultrasonic transducer 20 that generates and receives ultrasonic waves and a control module 10 that controls the frequency of the ultrasonic waves generated by the ultrasonic transducer 20.

[0059] The ultrasonic transducer 20 may be configured with an aluminum shell and piezoelectric elements to have a resonant point.

[0060] When driving a conventional ultrasonic sensor 100, the ultrasonic sensor 100 is driven by applying a burst pulse at the frequency of the series resonant point Fc, which has the highest sensitivity and is the most stable.

[0061] The control unit 200 of the control system of the vehicle ultrasonic sensor 100 according to the present invention sets a guard band at the series resonant point Fc, selects frequencies that separate up to the guard band, and sets multiple frequencies. Then, the multiple set frequencies are respectively applied to the multiple ultrasonic sensors 100, so that the ultrasonic sensors 100 can be driven at different frequencies from each other.

[0062] This allows multiple ultrasonic sensors 100 to be driven at different frequencies, thereby enabling a reduction in measurement and data update time.

[0063] As Figure 3 indicated, the control unit 200 can select frequencies A, B, and C including a resonance point Fc and having a plurality of guard bands set, and drive the ultrasonic sensors 100. SLS is system level sensitivity, which indicates the sensitivity characteristics of the system (i.e., the sensor) over the entire frequency range.

[0064] The control unit 200 can group adjacent ultrasonic sensors 100 among the plurality of ultrasonic sensors 100, and set the plurality of grouped ultrasonic sensors 100 to different driving frequencies from each other.

[0065] As Figure 6 indicated, the plurality of ultrasonic sensors 100 can be installed at the front, side, or rear of the vehicle, and the control unit 200 can group adjacent ultrasonic sensors 100 among the plurality of ultrasonic sensors installed in the vehicle into a plurality of subgroups, and drive the grouped ultrasonic sensors 100 at different frequencies from each other, respectively.

[0066] For example, the control unit 200 can group the six sensors in the front half of the vehicle as indicated in Figure 6

[0067] This allows the effect of reducing the operation time of the conventional ultrasonic sensor 100 by half.

[0068] For example, when the ultrasonic sensors 100 are grouped into two subgroups, two frequencies can be used, and when the ultrasonic sensors 100 are grouped into three subgroups, three frequencies can be used. When two frequencies are used, there is an effect of shortening the sensing period by half, and when three frequencies are used, there is an effect of shortening the sensing period by two-thirds.

[0069] The control module 10 can include a filter 11 having a cutoff frequency set to filter the received ultrasonic waves, and the control unit 200 can set the guard band according to the characteristics of the filter 11.

[0070] As Figure 1 indicated, the control module 10 of the ultrasonic sensor 100 can include a filter 11 so that the control module 10 receives the ultrasonic waves emitted from the ultrasonic transducer 20.

[0071] The filter 11 can be set to pass only the ultrasonic frequency components in a specific frequency band, and the guard band can be set by the control unit 200 according to the characteristics of the filter 11 installed in the ultrasonic sensor 100.

[0072] ​The type of the filter 11 can be as follows.

[0073] The filter 11 can include a band pass filter 11 that passes only frequencies within a preset frequency band width, and the control unit 200 can set the guard band to a value greater than the preset frequency band width in the band pass filter 11.

[0074] As shown in FIG. 1, Figure 4 The band pass filter 11 can be applied to the first embodiment of the filter 11. The band pass filter 11 is a filter 11 that passes only a desired frequency component and has a cutoff frequency f1 and f2 that forms a preset frequency band before and after the band pass filter.

[0075] Thus, the band pass filter 11 can pass only frequencies within the cutoff frequency.

[0076] The frequency band preset in the band pass filter 11 can be preset to a frequency in a frequency band in which a voltage converted in the ultrasonic transducer is reduced by half.

[0077] In the preset frequency band of the band pass filter 11, in order to accurately receive the ultrasonic wave, a frequency in which the voltage is reduced by half (i.e., a -3dB frequency) can be set as the cutoff frequency.

[0078] The frequency band preset in the band pass filter 11 can be preset by a Q factor and a center frequency of the frequency of the ultrasonic wave.

[0079] The Q factor is a value indicating the sharpness of resonance in a resonant circuit, and is defined as Q = w0L / R, where, in a relationship between reactance and resistance, w0 is a resonance angular frequency of the resonant circuit, L is inductance, and R is resistance. Among them, w0 = 2πf0, where f0 is a resonance frequency. In addition, the value of the Q factor can be obtained by the formula Q = Fc / (F2–F1) in Figure 4

[0080] For example, if it is assumed that, as shown in FIG. 1, Figure 3 a band pass filter 11 having Fc of 50 kHz and Q = 10 is used, the bandwidth of the driving signal is 5 kHz (+2.5 kHz), and if it is assumed that the number of driving frequencies is 3, 45 kHz, 50 kHz, and 55 kHz can be selected to use, and the bandwidth of the guard band for each driving frequency is 5 kHz.

[0081] The filter 11 can include a matched filter 11 that determines whether the received driving frequency is a valid frequency based on a common element between a preset reference frequency and the received driving frequency, and the control unit 200 can set the guard band based on the preset reference frequency.

[0082] As shown in FIG. 1, Figure 5 ​As shown, the matched filter 11 can be used in the second embodiment of the filter 11. When the matched filter 11 is used, the reference signal (reference frequency) and the received signal (received frequency) can be compared to determine whether the received signal (received frequency) is a valid signal (frequency) based on the number of common elements.

[0083] This allows the advantage of being able to selectively receive an extremely weak and specific signal among many noise signals.

[0084] The control unit 200 can select a plurality of frequencies at a driving frequency point and set the plurality of frequencies.

[0085] When the plurality of frequencies is set, the control unit 200 can select one driving point and set the plurality of frequencies using amplitude modulation (AM) or a burst pulse.

[0086] Further, in another embodiment, the control unit 200 can set the plurality of frequencies by frequency modulation (FM).

[0087] The control unit 200 can set the plurality of frequencies by a modulation method that changes the frequency of a carrier wave according to the amplitude of a signal wave.

[0088] When the ultrasonic sensor is driven using the present application, the sensor can be driven in the form of a frequency chirp as well as in the form of a conventional single-frequency burst pulse. When the ultrasonic sensor is driven in the form of a frequency chirp, the frequency band in which the sensor is driven is wider than when the sensor is driven by a single-frequency burst pulse, so that a guard band needs to be sufficiently secured in consideration of the chirp bandwidth.

[0089] The control unit 200 can compensate for the sensitivity of the ultrasonic wave reflected from the target and received, and control the control module 10 for sensing the target.

[0090] As shown in FIGS. 1 and 2, the ultrasonic sensor 100 can include an ultrasonic transducer 20 that generates and receives an ultrasonic wave, and a control module 10 that controls the frequency of the ultrasonic wave generated in the ultrasonic transducer 20. Figure 1 and Figure 2 As shown, the ultrasonic sensor 100 can include an ultrasonic transducer 20 that generates and receives an ultrasonic wave, and a control module 10 that controls the frequency of the ultrasonic wave generated in the ultrasonic transducer 20.

[0091] The ultrasonic transducer 20 can be configured with an aluminum case and a piezoelectric element to have a resonance point.

[0092] When a conventional ultrasonic sensor 100 is driven, the ultrasonic sensor 100 is driven by applying a burst pulse at a frequency at which the series resonance point Fc is maximally sensitive and most stable.

[0093] The control unit 200 of the control system of the vehicle ultrasonic sensor 100 according to the present application sets a guard band at the series resonance point Fc, and sets a plurality of frequencies by selecting frequencies separated by as much as the guard band. Then, the plurality of set frequencies are respectively applied to the plurality of ultrasonic sensors 100 so that the ultrasonic sensors 100 can be driven at frequencies different from each other.

[0094] This allows the plurality of ultrasonic sensors 100 to be driven at frequencies different from each other, respectively, thereby allowing the effect of shortening the time in measurement and data update.

[0095] Further, as Figure 8 indicated, the frequency / sensitivity characteristic of the ultrasonic sensor 100 can be such that the sensitivity can be even around the center frequency when the ultrasonic transducer 20 and the matching circuit are perfectly matched, and the frequency / sensitivity characteristic can not be symmetrical to the right and left of the center frequency when the component characteristics change due to various factors such as the environment, etc.

[0096] That is, when different frequencies around Fc are selected to drive the ultrasonic sensors, the sensor sensitivity difference at the different frequencies causes a sensitivity difference between the sensors. That is, it is necessary to perform measurement after adjusting the sensitivity to the same level.

[0097] In general, when sensing an object using the ultrasonic sensor 100, the sensor sensitivity serves as an important factor. Therefore, as Figure 8 indicated, when a plurality of frequencies are used, the control unit 200 can adjust the sensitivity at different frequencies to the sensitivity at the center frequency.

[0098] This allows the effect of accurately sensing an object even when a plurality of ultrasonic sensors 100 are driven using a plurality of frequencies.

[0099] Figure 6 is a view illustrating a mounting position of the vehicle ultrasonic sensor 100 according to an embodiment of the present application.

[0100] As Figure 6 indicated, a plurality of ultrasonic sensors 100 can be installed in a vehicle, and the control unit 200 can group adjacent ultrasonic sensors 100 among the plurality of ultrasonic sensors 100, and set a plurality of grouped ultrasonic sensors 100 to different driving frequencies from each other.

[0101] The plurality of ultrasonic sensors 100 can be provided at the front, rear, or side of the vehicle to assist the driver in driving. For example, a total of twelve ultrasonic sensors 100 (six in the front half and six in the rear half) can be installed, and four to twelve ultrasonic sensors 100 can be installed according to the vehicle option or the vehicle type.

[0102] If multiple ultrasonic frequencies are to be used, the ultrasonic sensor 100 needs to have a wide frequency band. Since this increases the cost, the control unit 200 can group a portion of adjacent ultrasonic sensors 100 among the multiple ultrasonic sensors 100 and drive the grouped ultrasonic sensors 100 using two to three ultrasonic frequencies.

[0103] Since the grouped ultrasonic sensors 100 are driven using multiple frequencies, this allows the effect of shortening the sensing period to be achieved compared to conventional technology.

[0104] For example, when the ultrasonic sensors 100 are grouped into two subgroups, two frequencies can be used, and when the ultrasonic sensors 100 are grouped into three subgroups, three frequencies can be used. When two frequencies are used, there is an effect of shortening the sensing period by half, and when three frequencies are used, there is an effect of shortening the sensing period by two-thirds.

[0105] The control unit 200 can set a reference sensitivity of the frequency of the received ultrasonic waves and increase or decrease the frequency of the ultrasonic waves reflected from the target and received to sense at the reference sensitivity.

[0106] As shown in FIG. 4, Figure 7 Generally, due to the frequency sensitivity characteristic, both sides can appear to be asymmetric.

[0107] In contrast, when multiple frequencies are used, the control unit 200 can adjust the magnitude of the center frequency by increasing or decreasing the magnitude of the frequency with respect to the reference sensitivity to match the reference sensitivity.

[0108] This allows the effect of accurately sensing the target even if multiple frequencies are used.

[0109] The control unit 200 can pre-map the component characteristics or temperature of the ultrasonic sensor 100, predict the sensor sensitivity at a certain frequency based on the pre-mapping, and convert the sensor sensitivity to a reference sensitivity for sensing.

[0110] The frequency / sensitivity characteristic of the ultrasonic sensor 100 can be determined by the characteristics of the ultrasonic transducer 20 and the matching circuit, and when the component characteristics change due to different factors (temperature, component aging), the frequency / sensitivity characteristic of the ultrasonic sensor 100 can undergo a change.

[0111] As shown in FIG. 6, Figure 7 In the ultrasonic sensitivity characteristic, A, B, C are a graph of the frequency / sensitivity characteristic showing the minimum / maximum values selected for the main characteristic values of the ultrasonic transducer 20 for each ultrasonic sensor 100, and although there are differences in the characteristics of the ultrasonic transducer 20, the difference caused by the temperature difference remains the same.

[0112] Thus, the control unit 200 can pre-map the sensitivity adjustment value according to the component characteristics or temperature of the ultrasonic sensor 100, and adjust the frequency sensitivity based on the pre-mapping to allow reception of sensing information.

[0113] Figure 9 is a graph showing a transfer function and a phase curve of the ultrasonic sensor 100 diagnosed by the sensor diagnosis unit 300.

[0114] The sensor diagnosis unit 300 can diagnose the ultrasonic sensor 100 and calculate a transfer function of the ultrasonic sensor 100, and the control unit 200 can predict an element value of the ultrasonic sensor 100 in the equivalent circuit based on the transfer function of the ultrasonic sensor 100 calculated by the sensor diagnosis unit 300, and convert the element value into a reference sensitivity for sensing.

[0115] Adjustment of the frequency sensitivity based on the pre-mapping causes a problem in that characteristics of the ultrasonic transducer 20 and the matching circuit vary much more than expected at the time of pre-mapping, and in addition, factors such as component aging can vary much more than the initial management value.

[0116] To solve this problem, the sensor diagnosis unit 300 can diagnose the ultrasonic sensor 100 and calculate a transfer function, and the control unit 200 can adjust the sensitivity of the ultrasonic sensor 100 to a reference sensitivity by inferring an element value on the equivalent circuit taken by the ultrasonic transducer 20 and the matching circuit based on the calculated transfer function.

[0117] Figure 10 is a graph showing a change in an attenuation coefficient of an ultrasonic wave in air according to temperature / humidity under the same frequency / atmospheric pressure.

[0118] The sensing unit 400 can sense an external temperature or humidity, the ultrasonic wave generated by the ultrasonic sensor 100 is transmitted through the external temperature or humidity, and the control unit 200 can calculate an attenuation coefficient of the ultrasonic wave in air according to the temperature or humidity sensed by the sensing unit 400, and convert the attenuation coefficient into a reference sensitivity for sensing.

[0119] An ultrasonic wave is attenuated according to a state of a medium (air, etc.) at the time of generation. In particular, since the ultrasonic wave is affected by factors (temperature, humidity, atmospheric pressure, frequency) of the medium, it is necessary to consider characteristics of the medium after adjustment based on pre-mapping or sensor diagnosis is performed.

[0120] As Figure 10As illustrated, since the attenuation coefficient of the ultrasonic wave in the air changes according to the temperature and humidity, the sensing unit 400 can sense the temperature or humidity of the air, and the control unit 200 can adjust the sensitivity of the ultrasonic sensor 100 based on the sensed temperature or humidity.

[0121] This allows the effect of precisely adjusting the frequency sensitivity of the ultrasonic sensor 100 in several steps.

[0122] The control unit 200 can perform the sensitivity adjustment of each ultrasonic sensor 100 when the ultrasonic sensor 100 starts operation or when the vehicle shifts gears.

[0123] The control unit 200 can perform the sensitivity adjustment of the ultrasonic sensor 100 when the vehicle starts or when the vehicle gear is switched to the forward or reverse gear.

[0124] This allows the effect of stably receiving the signal of the ultrasonic sensor 100 by adjusting the sensitivity of the ultrasonic sensor 100 in response to the changing environment of the vehicle.

[0125] Figure 11 is a flowchart of a vehicle ultrasonic sensor 100 control method according to the present application.

[0126] A preferred embodiment of a vehicle ultrasonic sensor 100 control method according to the present application will be described with reference to Figure 11 A preferred embodiment of a vehicle ultrasonic sensor 100 control method according to the present application will be described with reference to

[0127] The vehicle ultrasonic sensor 100 control method according to the present application includes setting a plurality of drive frequencies having a guard band therebetween (S11), controlling so that a plurality of ultrasonic sensors 100 emit and receive ultrasonic waves having the set drive frequencies different from each other (S12), and compensating the sensitivity of the ultrasonic wave reflected from the target and received for sensing the target (S50).

[0128] It can further include, before setting the drive frequencies, grouping adjacent ultrasonic sensors 100 among the plurality of ultrasonic sensors 100 (S10), and at the time of controlling, the plurality of grouped ultrasonic sensors 100 can be set to the drive frequencies different from each other.

[0129] In the sensing of the target (S50) can include setting a reference sensitivity of the received ultrasonic wave, and increasing or decreasing the frequency of the ultrasonic wave reflected from the target and received to sense at the reference sensitivity (S54).

[0130] It is also possible to include pre-mapping of component characteristics or temperature of the ultrasonic sensor 100 (S20), and in the sensing of the target (S50) it is possible to include predicting the sensor sensitivity at a certain frequency based on the pre-mapping and converting the sensor sensitivity into a reference sensitivity (S51).

[0131] It is also possible to include diagnosing the ultrasonic sensor 100 and calculating a transfer function of the ultrasonic sensor 100 (S30), and in the sensing of the target (S50) it is possible to include predicting an element value of the ultrasonic sensor 100 in an equivalent circuit based on the transfer function of the ultrasonic sensor 100 calculated by the sensor diagnosis unit 300 and converting the element value into a reference sensitivity for the sensing (S52).

[0132] It is also possible to include sensing an external temperature or humidity (S40) through which the ultrasonic waves generated by the ultrasonic sensor 100 are transmitted, and in the sensing of the target it is possible to include calculating an attenuation coefficient of the ultrasonic waves in the air according to the sensed temperature or humidity and converting the attenuation coefficient into a reference sensitivity for the sensing (S53).

[0133] Specific embodiments of the present application are illustrated and described, but it is obvious to those skilled in the art that the present application can be improved and modified in various ways without departing from the technical spirit of the present application provided by the following patent claims.

Claims

1. A system for controlling ultrasonic sensors of a vehicle, comprising: a plurality of ultrasonic sensors attached to the vehicle, each ultrasonic sensor including: an ultrasonic transducer configured to generate ultrasonic waves; and a control module configured to control a driving frequency of the ultrasonic waves emitted from the ultrasonic transducer; and a control unit configured to: set a plurality of driving frequencies, a guard band being located between the plurality of driving frequencies; and control the control module such that a driving frequency of the ultrasonic waves emitted and received by each ultrasonic sensor is different from a driving frequency of the ultrasonic waves emitted and received from other ultrasonic sensors; wherein the control module includes a filter having a cutoff frequency set to filter the received ultrasonic waves, the control unit is configured to set the guard band based on a characteristic of the filter, the filter includes: a matched filter configured to determine whether a driving frequency of the received ultrasonic waves is a valid frequency based on a common element between a preset reference frequency and the driving frequency of the received ultrasonic waves, and the control unit is configured to set the guard band based on the preset reference frequency. 2.The system of claim 1, wherein: the plurality of ultrasonic sensors are divided into a plurality of ultrasonic sensor groups, each ultrasonic sensor group including a number of ultrasonic sensors positioned adjacent to each other, and the control unit is configured to set the driving frequencies of each ultrasonic sensor group to be different from each other. 3.The system of claim 1, wherein: the filter includes a band pass filter that passes only frequencies within a preset frequency band width, and the control unit is configured to set a frequency band width of the guard band to a value greater than the preset frequency band width of the band pass filter.

4. The system of claim 3, wherein, the preset frequency band of the band pass filter includes frequencies in a frequency band in which a voltage converted in the ultrasonic transducer is reduced by half.

5. The system of claim 3, wherein, the preset frequency band in the band pass filter is preset based on a Q factor and a center frequency among frequencies of the ultrasonic waves.

6. The system of claim 1, wherein, the control unit is configured to select and set a plurality of frequencies at driving frequency points.

7. The system of claim 1, wherein, the control unit is configured to perform frequency modulation to set a plurality of frequencies.

8. The system of claim 1, wherein, the control unit is configured to compensate for a sensitivity of the ultrasonic waves reflected from a target and received, and control the control module for sensing the target.

9. The system of claim 8, wherein, the control unit is configured to: set a reference sensitivity of a frequency of the received ultrasonic waves; and increase or decrease the frequency of the ultrasonic waves reflected from the target and received to sense at the reference sensitivity.

10. The system of claim 9, wherein, the control unit is configured to: pre-map component characteristics or temperatures of the ultrasonic sensors; predict a sensor sensitivity at a specific frequency based on the pre-mapping; and convert the sensor sensitivity to the reference sensitivity. 4.The system of claim 1, wherein: the control unit is configured to: set a reference sensitivity of a frequency of the received ultrasonic waves; and increase or decrease the frequency of the ultrasonic waves reflected from the target and received to sense at the reference sensitivity. 5.The system of claim 1, wherein: the control unit is configured to: pre-map component characteristics or temperatures of the ultrasonic sensors; predict a sensor sensitivity at a specific frequency based on the pre-mapping; and convert the sensor sensitivity to the reference sensitivity.

11. The system of claim 9, further comprising: a sensor diagnosis unit configured to diagnose the ultrasonic sensor and calculate a transfer function of the ultrasonic sensor, wherein the control unit is configured to predict element values of the ultrasonic sensor in an equivalent circuit based on the transfer function of the ultrasonic sensor calculated by the sensor diagnosis unit and convert the element values into the reference sensitivity.

12. The system of claim 9, further comprising: a sensing unit configured to sense an outside temperature or humidity of air around the vehicle through which the ultrasonic waves generated by the ultrasonic sensor are transmitted, wherein the control unit is configured to calculate an attenuation coefficient of the ultrasonic waves in the air according to the sensed outside temperature or humidity and convert the attenuation coefficient into the reference sensitivity. 13.A method of operating a vehicle ultrasonic sensor for sensing a target, comprising: setting a plurality of drive frequencies for a plurality of ultrasonic sensors, wherein the plurality of drive frequencies are separated from each other, and a guard band is located between the plurality of drive frequencies; controlling a plurality of the ultrasonic sensors to transmit and receive ultrasonic waves, wherein a drive frequency of the ultrasonic waves transmitted and received by each ultrasonic sensor is different from drive frequencies of the ultrasonic waves transmitted and received by other ultrasonic sensors; compensating for sensitivity of the ultrasonic waves reflected from the target and received; and sensing the target based on the compensated sensitivity of the ultrasonic waves reflected from the target and received; the method further comprising filtering the received ultrasonic waves by a filter having a cutoff frequency, the filter including a matched filter configured to determine whether a drive frequency of the received ultrasonic waves is a valid frequency based on a common element between a preset reference frequency and the drive frequency of the received ultrasonic waves, and the guard band being set based on the preset reference frequency and a characteristic of the filter.

14. The method of claim 13, further comprising: dividing the plurality of the ultrasonic sensors into a plurality of ultrasonic sensor groups each including a number of ultrasonic sensors positioned adjacent to each other, wherein each ultrasonic sensor group is configured to operate at a drive frequency different from drive frequencies of other ultrasonic sensor groups.

15. The method of claim 13, wherein, sensing the target includes: setting a reference sensitivity for the drive frequency of the received ultrasonic waves; and increasing or decreasing the drive frequency of the ultrasonic waves reflected from the target and received to sense at the reference sensitivity.

16. The method of claim 15, further comprising: pre-mapping component characteristics or temperature of the ultrasonic sensor, wherein sensing the target further includes: predicting a sensor sensitivity at a specific frequency based on the pre-mapping; and converting the sensor sensitivity into the reference sensitivity. 17.The method of claim 15, further comprising diagnosing the ultrasonic sensor and calculating a transfer function of the ultrasonic sensor, wherein sensing the target includes: predicting element values of the ultrasonic sensor in an equivalent circuit unit based on the calculated transfer function; and converting the element values into the reference sensitivity.

18. The method of claim 15, further comprising: sensing an outside temperature or humidity of air around the vehicle through which the ultrasonic waves generated by the ultrasonic sensor are transmitted, wherein sensing the target includes: calculating an attenuation coefficient of the ultrasonic waves from the sensed temperature or humidity; and converting the attenuation coefficient into the reference sensitivity.

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