Ultrasonic sensor device and detection method of an ultrasonic sensor device

Abstract

Ultrasonic sensor device comprising: a driver unit (10) for providing a transmission pulse to a transducer that transmits an ultrasonic wave and receives an echo of the ultrasonic wave; an amplifier (20) for amplifying an electrical signal for the echo; an analog-to-digital converter (30) for converting the amplified electrical signal into an original digital signal; a signal processor (40) for performing envelope extraction processing on the original digital signal to generate an extracted signal; and a control unit (50) for outputting a distance signal related to an external object based on the original digital signal and the extracted signal, wherein the control unit comprises: a test frequency generator (51) for applying a test frequency signal to the converter; an excitation frequency measuring unit (52) for measuring an excitation frequency generated in the transducer; and an optimal frequency calculator (53) for calculating an optimal frequency using the excitation frequency, where the excitation frequency is the frequency of an excitation that oscillates freely in an excitation mode range between a transmission mode and a reception mode of the transducer, and wherein the optimal frequency is an intermediate value between the excitation frequency and an anti-resonance frequency.

Description

BACKGROUND AREA

[0001] The present invention relates to an ultrasonic sensor, and more particularly to an ultrasonic sensor device and a detection method of an ultrasonic sensor device. STATE OF THE ART

[0002] Recently, vehicle manufacturers have been developing and introducing advanced safety technologies to the market. A typical example is modern advanced driver assistance systems (ADAS), which are primarily used in conjunction with parking. In particular, parking assistance systems and automatic parking assistance systems are widely used to indicate the distance between the vehicle and an object when parking. In this system, the essential technologies include a technique for measuring the position of objects around the vehicle or the distance between the objects and the vehicle using an ultrasonic sensor.

[0003] An ultrasonic sensor is a sensor that emits an ultrasonic wave with a frequency of 20 kHz or more in an inaudible range and then detects an ultrasonic echo reflected from an external object to measure the distance to the external object. In automobiles, the ultrasonic echo detected by the ultrasonic sensor is used to measure the distance to an object around the vehicle and inform the driver in a variety of ways, such as a warning sound, a display on the vehicle's screen, and the like.

[0004] However, distance measuring devices using conventional ultrasonic sensors have limitations in terms of distance range or accuracy. As the need for various applications that exceed the limits of the detection range and accuracy of conventional ultrasonic sensors gradually increases, improving existing distance measuring systems using ultrasonic sensors has become particularly urgent. For example, expanding the detection range of existing ultrasonic sensors and improving their accuracy has become necessary for many reasons, enabling them to detect a smaller distance for more efficient parking in tight spaces.

[0005] Such a conventional ultrasonic sensor device operates at constant transmission / reception frequencies, regardless of changes in the position of the ultrasonic sensor array and the surrounding environment in which the ultrasonic sensor device is located. The ultrasonic sensor device thus has a limited ability to detect objects.

[0006] A prior art document is US Patent No. US 7,046,015 (issued on May 16, 2006).

[0007] Another relevant publication, US 2011 / 0261652 A1, presents an acoustic distance measurement system that can dynamically adjust its measurement frequency to a frequency within a preselected bandwidth around the resonant frequency of an acoustic transducer. The system ensures that the actual resonant frequency is taken into account, although the actual resonant frequency depends on operating conditions. SHORT SUMMARY

[0008] The present invention has been made in an effort to solve or alleviate various problems including the above-mentioned problems. An object of the present invention is to provide an ultrasonic sensor device and a detection method of the device, in which the frequency in the resonant frequency band of the transducer is applied to detect the frequency of the reverberation signal of the transducer, and then the amplitudes at the corresponding frequencies are compared to determine the optimal transmission and reception frequencies of the transducer, so that an optimal transmission and reception frequency is determined according to the geometric shape and size of the transducer, and an optimal transmission and reception frequency of the transducer is determined even in various environments (temperature, humidity, poor condition, etc.).An improvement in object detection capability is thus achieved. However, these problems are merely illustrative, and the scope of the present invention is not limited thereto.

[0009] According to one aspect of the present invention, an ultrasonic sensor device is provided. The ultrasonic sensor device comprises: a driver unit for providing a transmission pulse to a transducer that transmits an ultrasonic wave and receives an echo of the ultrasonic wave, an amplifier for amplifying an electrical signal for the echo, an analog-to-digital converter for converting the amplified electrical signal into an original digital signal, a signal processor for performing envelope extraction processing on the original digital signal to generate an extracted signal, and a control unit for outputting a distance signal relative to an external object based on the original digital signal and the extracted signal. The control unit may comprise: a test frequency generator for applying a test frequency signal to the transducer.an excitation frequency measuring unit for measuring the excitation frequency generated in the transducer, and an optimal frequency calculator for calculating an optimal frequency using the excitation frequency.

[0010] The excitation frequency is the frequency of an excitation that oscillates freely in an excitation mode range between a transmission mode and a reception mode of the transducer.

[0011] The optimal frequency is an intermediate value between the excitation frequency and an anti-resonance frequency.

[0012] In the ultrasonic sensor device, the excitation frequency generated in the transducer may be a resonant frequency of the transducer.

[0013] In the ultrasonic sensor device, the control unit may further comprise: a transmission pulse calibration device for calibrating the transmission pulse frequency taking into account the optimal frequency.

[0014] According to one aspect of the present invention, there is provided a detection method of an ultrasonic sensor device comprising a drive unit for providing a transmission pulse to a transducer that transmits an ultrasonic wave and receives the echo of the ultrasonic wave, an amplifier for amplifying an electrical signal for the echo, an analog-to-digital converter for converting the amplified electrical signal into an original digital signal, a signal processor for performing envelope extraction processing on the original digital signal to generate an extracted signal, and a control unit for outputting a distance signal with respect to an external object based on the original digital signal and the extracted signal.The method includes: a test frequency application step for applying a test frequency signal to the transducer, an excitation frequency measuring step for measuring an excitation frequency generated in the transducer according to the test frequency signal, an optimal frequency calculation step for calculating an optimal frequency using the excitation frequency, and a transmission pulse frequency calibration step for calibrating a transmission pulse frequency taking into account the optimal frequency.

[0015] In the excitation frequency measuring step, the excitation frequency is the frequency of an excitation that oscillates freely in an excitation mode range between a transmission mode and a reception mode of the transducer.

[0016] The optimal frequency calculation step is a step for calculating an intermediate value between the excitation frequency and an anti-resonance frequency.

[0017] In the detection method, in the excitation frequency measuring step, the excitation frequency generated in the transducer may be a resonant frequency of the transducer. BENEFICIAL EFFECTS

[0018] According to one embodiment of the present invention described above, the frequency in the resonant frequency band of the transducer is applied to determine the frequency of the reverberation signal of the transducer, and then the amplitudes at the corresponding frequencies are compared to determine the optimal transmission and reception frequencies of the transducer. Thus, an optimal transmission and reception frequency is determined according to the geometric shape and size of the transducer, and an optimal transmission and reception frequency of the transducer is determined even in various environments (temperature, humidity, old age, etc.). An improvement effect on the object detection capability is thus achieved. The scope of the present invention is, of course, not limited by these effects. DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing an ultrasonic sensor device according to an embodiment of the present invention. Fig. Figure 2 is a graph showing the transmission and reception frequencies produced by a transducer of the ultrasonic sensor device Fig. 1 can be generated. Fig. 3 is a graph showing the in the transducer of the ultrasonic sensor device of Fig. 1 shows the excitation frequency generated. Fig. 4 is a flowchart illustrating a detection method of an ultrasonic sensor device according to an embodiment of the present invention. <Erläuterung der Bezugszeichen> 10 Driver unit 20 amplifiers 30 analog-to-digital converters 40 Signal processor 50 control unit 51 test frequency generator 52 Excitation frequency measuring unit 53 optimal frequency calculator 54 Transmission pulse calibration device T converter RF excitation frequency OF optimal frequency AF anti-resonance frequency DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0020] These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. However, it is to be understood that this invention is not limited to the embodiments described below, but may be embodied in various other forms. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The thickness or size of each layer in the drawings is exaggerated for simplicity and clarity of explanation.

[0021] Fig. 1 is a schematic view showing an ultrasonic sensor device according to an embodiment of the present invention, Fig. Figure 2 is a graph showing the transmission and reception frequencies provided by a transducer of the ultrasonic sensor device Fig. 1 are generated, and Fig. Figure 3 is a graph showing the excitation frequency output from the transducer of the ultrasonic sensor device Fig. 1 is generated.

[0022] As in Fig. 1, an ultrasonic sensor device according to an embodiment of the present invention may include a driver unit 10, an amplifier 20, an analog-to-digital converter 30, a signal processor 40, and a control unit 50.

[0023] As in Fig. As shown in Figure 1, the driver unit 10 can provide a transmission pulse to a transducer T, which transmits an ultrasonic wave and receives the echo of the ultrasonic wave. Specifically, the driver unit 10 can provide the transmission pulse to the transducer T such that the transducer T oscillates and transmits the ultrasonic wave. The transducer T can receive the echo of the transmitted ultrasonic wave and convert the echo into an electrical signal.

[0024] The amplifier 20 can amplify the electrical signal for the echo. Specifically, the amplifier 20 can amplify the electrical signal for the echo of the ultrasonic wave received by the transducer T and can be operated by dynamically changing the amplification factor according to the distance to an external object.

[0025] The analog-to-digital converter 30 can convert the amplified electrical signal into an original digital signal. Specifically, the analog-to-digital converter 30 can convert the electrical signal amplified by the amplifier 20 into a digital signal and transmit the digital signal to the signal processor 40.

[0026] Furthermore, the signal processor 40 can perform envelope extraction processing on the original digital signal to generate an extracted signal. Specifically, the signal processor 40 can be a module for converting / processing into a signal that can be analyzed by the control unit 50, such as removing noise from the original digital signal for the ultrasonic echo and extracting an envelope. For example, the signal processor can include a bandpass filter that filters a specific frequency range around a transmission frequency with various digital filters, an envelope extractor that extracts an envelope from a signal passed through the bandpass filter, and a lowpass filter that extracts noise from the extracted signal, and the like.

[0027] The control unit 50 can output a distance signal to an external object based on the original digital signal and the extracted signal. The control unit 50 can include a test frequency generator 51 for applying a test frequency signal to the transducer T, an excitation frequency measuring unit 51 for measuring the excitation frequency RF generated by the transducer T, an optimal frequency calculator 53 for calculating an optimal frequency OF using the excitation frequency RF, and a transmission pulse calibration unit 54 for calibrating the transmission pulse frequency taking into account the optimal frequency OF. The excitation frequency RF generated in the transducer T can be the resonant frequency of the transducer T.

[0028] As in Fig. 2, the excitation frequency RF can be, for example, a frequency of the excitation that oscillates freely in the excitation mode range between the transmission mode and the reception mode of the transducer T. As shown in Fig. 3, the optimal frequency OF can also be an intermediate value between the excitation frequency RF and the anti-resonance frequency AF.

[0029] As in the Fig. 1 to 3, the control unit 50 of the ultrasonic sensor device according to the embodiment of the present invention can control the drive unit 10 so that the transducer T oscillates at a value between the excitation frequency RF and the anti-resonance frequency AF of the transducer T in consideration of the transmitted test frequency and the reception sensitivity of the excitation frequency RF according to the received echo of the test frequency, thereby outputting a transmission pulse.

[0030] Whenever the vehicle-mounted ultrasonic sensor device is operated, the control unit 50 of the ultrasonic sensor device, for example, can control the driver unit 10 so that the transducer T oscillates at a value between the excitation frequency RF and the anti-resonance frequency AF of the transducer T, taking into account the transmitted test frequency and the reception sensitivity of the excitation frequency RF according to the received echo of the test frequency, thereby outputting a transmission pulse. The ultrasonic sensor device can thus transmit and receive at an optimal frequency in response to various environments around the vehicle.

[0031] Thus, the frequency in the resonant frequency band of the transducer T is applied to determine the frequency of the signal from the transducer T. Then, the amplitudes at the corresponding frequencies are compared to determine the optimal transmission and reception frequencies of the transducer T. This allows optimal transmission and reception frequencies to be determined according to the geometric shape and size of the transducer T, and also allows optimal transmission and reception frequencies of the transducer T to be determined in different environments (temperature, humidity, old age, etc.). An improvement effect on the object detection capability is thus achieved.

[0032] Fig. 4 is a flowchart illustrating a detection method of an ultrasonic sensor device according to an embodiment of the present invention.

[0033] As in Fig.4, the detection method of the ultrasonic sensor device, which includes a driver unit 10 for providing a transmission pulse to a transducer T that transmits an ultrasonic wave and receives the echo of the ultrasonic wave, an amplifier 20 for amplifying the electrical signal for the echo, an analog-to-digital converter 30 for converting the amplified electrical signal into an original digital signal, a signal processor 40 for performing envelope extraction processing on the original digital signal to generate an extracted signal, and a control unit 50 for outputting a distance signal related to an external object based on the original digital signal and the extracted signal, includes the following: a test frequency application step S10 for applying a test frequency signal to the transducer T, an excitation frequency measurement step S20 for measuring an excitation frequency RF,which is generated according to the test frequency signal in the converter T, an optimal frequency calculation step S30 for calculating an optimal frequency OF using the excitation frequency RF and a transmission pulse frequency calibration step S40 for calibrating a transmission pulse frequency taking into account the optimal frequency OF.

[0034] In the excitation frequency measurement step S20, the excitation frequency RF generated in the transducer T may, in particular, be the resonance frequency of the transducer T. In the excitation frequency measurement step S20, the excitation frequency RF may, for example, be the frequency of an excitation that oscillates freely in the excitation mode range between the transmission mode and the reception mode of the transducer T. The optimal frequency calculation step S30 may also be a step for calculating an intermediate value between the excitation frequency RF and the anti-resonance frequency AF.

[0035] As shown in FIG. 4, according to the detection method of an ultrasonic sensor device according to an embodiment of the present invention, the control unit 50 of the ultrasonic sensor device can control the drive unit 10 so that the transducer T oscillates at a value between the excitation frequency RF and the anti-resonance frequency AF of the transducer T, taking into account the transmitted test frequency and the reception sensitivity of the excitation frequency RF according to the received echo of the test frequency, thereby outputting a transmission pulse. The ultrasonic sensor device can thus transmit and receive at an optimal frequency in response to various environments around the vehicle.

[0036] Thus, the frequency in the resonant frequency band of the transducer T is applied to determine the frequency of the reverberation signal of the transducer T. Then, the amplitudes at the corresponding frequencies are compared to determine the optimal transmission and reception frequencies of the transducer T. This allows optimal transmission and reception frequencies to be determined according to the geometric shape and size of the transducer T, and also allows optimal transmission and reception frequencies of the transducer T to be determined in different environments (temperature, humidity, old age, etc.). An improvement effect on the object detection capability is thus achieved.

[0037] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but rather is intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims. Thus, the true scope of the present invention is to be determined by the technical spirit of the appended claims.

Claims

[1] Ultrasonic sensor device comprising: a driver unit (10) for providing a transmission pulse to a transducer that transmits an ultrasonic wave and receives an echo of the ultrasonic wave; an amplifier (20) for amplifying an electrical signal for the echo; an analog-to-digital converter (30) for converting the amplified electrical signal into an original digital signal; a signal processor (40) for performing envelope extraction processing on the original digital signal to generate an extracted signal; and a control unit (50) for outputting a distance signal related to an external object based on the original digital signal and the extracted signal, wherein the control unit comprises: a test frequency generator (51) for applying a test frequency signal to the converter; an excitation frequency measuring unit (52) for measuring an excitation frequency generated in the transducer; and an optimal frequency calculator (53) for calculating an optimal frequency using the excitation frequency, where the excitation frequency is the frequency of an excitation that oscillates freely in an excitation mode range between a transmission mode and a reception mode of the transducer, and wherein the optimal frequency is an intermediate value between the excitation frequency and an anti-resonance frequency. [2] The device of claim 1, wherein the excitation frequency generated in the transducer is a resonant frequency of the transducer. [3] The apparatus of claim 1, wherein the control unit further comprises: a transmission pulse calibration device (54) for calibrating a transmission pulse frequency taking into account the optimal frequency. [4] A detection method of an ultrasonic sensor device comprising a driver unit (10) for providing a transmission pulse to a transducer that transmits an ultrasonic wave and receives the echo of the ultrasonic wave, an amplifier (20) for amplifying an electrical signal for the echo, an analog-to-digital converter (30) for converting the amplified electrical signal into an original digital signal, a signal processor (40) for performing envelope extraction processing on the original digital signal to generate an extracted signal, and a control unit (50) for outputting a distance signal with respect to an external object based on the original digital signal and the extracted signal, the method comprising: a test frequency application step for applying a test frequency signal to the converter; an excitation frequency measuring step for measuring an excitation frequency generated in the transducer according to the test frequency signal; an optimal frequency calculation step for calculating an optimal frequency using the excitation frequency; and a transmission pulse frequency calibration step for calibrating a transmission pulse frequency taking into account the optimal frequency, wherein in the excitation frequency measuring step, the excitation frequency is the frequency of an excitation that oscillates freely in an excitation mode range between a transmission mode and a reception mode of the transducer, and wherein the optimal frequency calculation step is a step of calculating an intermediate value between the excitation frequency and an anti-resonance frequency. [5] The method according to claim 4, wherein in the excitation frequency measuring step, the excitation frequency generated in the transducer is a resonance frequency of the transducer.

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