Ultrasonic sonar and vehicle

Abstract

To eliminate effects on ultrasonic signals reflected by an object, that arise from an overlap region between excitation signals of two sonars.SOLUTION: A sonar in one aspect of the present disclosure includes a first transducer having a first resonant frequency, a first signal generating circuit that generates a first excitation signal having a first frequency range that excites the first transducer, a second transducer having a second resonant frequency different from the first resonant frequency, and a second signal generating circuit that generates a second excitation signal for exciting the second transducer, having a second frequency range that does not overlap with the first frequency range.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to ultrasonic sonar and vehicles. [Background technology]

[0002] Conventional sonar is installed on vehicles and the like to detect targets.

[0003] In this regard, a system has been proposed in which two ultrasonic sonars having the same resonant frequency are used, and each sonar transmits a chirp-modulated excitation signal (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-035755 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the excitation signals of the two sonars, whose frequency ranges are fa and fb, have the same resonance frequency fR, so that the amplitude spectra of the ultrasonic signals emitted by the two sonars have an overlapping region where the spectral ranges overlap. Therefore, the ultrasonic signals emitted by the two sonars may interfere with each other, decreasing the detection accuracy of the target.

[0006] The present disclosure contributes to providing an ultrasonic sonar and a vehicle that can suppress a decrease in target detection accuracy. [Means for solving the problem]

[0007] A sonar in one embodiment of the present disclosure includes a first transducer having a first resonant frequency, a first signal generating circuit that generates a first excitation signal having a first frequency range that excites the first transducer, a second transducer having a second resonant frequency different from the first resonant frequency, and a second signal generating circuit that generates a second excitation signal having a second frequency range that excites the second transducer, the second frequency range being different from the first frequency range.

[0008] In one embodiment of the present disclosure, a vehicle is equipped with a sonar including a first transducer having a first resonant frequency, a first signal generating circuit that generates a first excitation signal having a first frequency range that excites the first transducer, a second transducer having a second resonant frequency different from the first resonant frequency, and a second signal generating circuit that generates a second excitation signal having a second frequency range that excites the second transducer, the second frequency range being different from the first frequency range. Effect of the Invention

[0009] According to an embodiment of the present disclosure, it is possible to suppress a decrease in the detection accuracy of a target. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a circuit configuration of an ultrasonic sonar according to a first embodiment. [Figure 2A] Diagram showing the frequency band of the sonar excitation signal [Figure 2B] Diagram showing chirp signal [Diagram 3] FIG. 13 is a diagram showing a circuit configuration of an ultrasonic sonar according to a second embodiment. [Figure 4] FIG. 13 is a diagram showing a circuit configuration of a system according to a third embodiment. [Diagram 5] FIG. 13 is a diagram showing a circuit configuration of a system according to a fourth embodiment. [Figure 6] FIG. 13 is a diagram showing a circuit configuration of an ultrasonic sonar according to a fifth embodiment. [Figure 7]FIG. 13 shows a circuit configuration of an ultrasonic sonar according to a sixth embodiment. [Figure 8] FIG. 23 shows a circuit configuration of a system according to a seventh embodiment. [Figure 9] FIG. 23 shows a circuit configuration of a system according to an eighth embodiment. [Figure 10] A diagram showing the reference value for determining whether to control the variable BPF. [Figure 11] FIG. 1 shows a system for adjusting the initial settings of an ultrasonic sonar according to the first to eighth embodiments. [Figure 12] Diagram showing a system for simultaneously adjusting the initial settings of two ultrasonic sonars [Figure 13] FIG. 13 is a flowchart showing an adjustment process of the initial settings in the first to fourth embodiments. [Figure 14] FIG. 13 is a flowchart showing an adjustment process of the initial settings in the fifth to eighth embodiments. [Figure 15] A diagram showing an example of two sonars being deployed on a vehicle. [Figure 16] A diagram showing an example of three sonars deployed on a vehicle. [Figure 17] A diagram showing an example of four sonars deployed on a vehicle. [Figure 18] A diagram showing a second example where four sonars are arranged on a vehicle. [Figure 19] A diagram showing a third example where four sonars are arranged on a vehicle. [Figure 20] A diagram showing a fourth example in which four sonars are arranged on a vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate.

[0012] (Embodiment 1) The circuit configuration of the ultrasonic sonar 100 according to the first embodiment of the present disclosure will be described.

[0013] 1, an ultrasonic sonar 100 includes sonars 110 and 120. A transmission signal 141 transmitted by the sonar 110 is reflected by a target 130, and a portion of the signal is received by the sonar 110 as a reflected signal 142, and a portion of the signal is received by the sonar 120 as a crossover signal 153.

[0014] A transmission signal 151 transmitted by the sonar 120 is reflected by the target 130 , and a portion of the signal is received by the sonar 120 as a reflected signal 152 , and a portion of the signal is received by the sonar 110 as a crossover signal 143 .

[0015] The ultrasonic sonar 100 can calculate the distance to the target 130 based on the delay time between the time the ultrasonic wave is transmitted and the time the ultrasonic wave is received.

[0016] The sonar 110 includes a CPU (Central Processing Unit) core 111a, a signal generating circuit 112a, a transmitting wave driving circuit 113a, an electroacoustic transducer 114a, a receiving wave amplifying circuit 115a, a wave detector 116a, and a correlator 117a. For example, the CPU core 111a, the signal generating circuit 112a, the wave detector 116a, and the correlator 117a are configured by a microprocessor 118a.

[0017] The sonar 120 includes a CPU core 111b, a signal generating circuit 112b, a transmitting drive circuit 113, an electroacoustic transducer 114b, a receiving amplifier circuit 115b, a detector 116b, and a correlator 117b. For example, the CPU core 111b, the signal generating circuit 112b, the detector 116b, and the correlator 117b are configured by a microprocessor 118b. The electroacoustic transducers 114a and 114b are also called ultrasonic microphones, ultrasonic microphones, microphones, microphones, or transducers.

[0018] The CPU core 111a can control the entire sonar 110. The CPU core 111a instructs the signal generating circuit 112a to generate a signal to be transmitted.

[0019] Furthermore, the CPU core 111a obtains the distance from the ultrasonic sonar 100 to the target 130 based on the delay time received from the correlator 117a.

[0020] The CPU core 111b can control the entire sonar 120. The CPU core 111b instructs the signal generating circuit 112b to generate a signal to be transmitted.

[0021] Furthermore, the CPU core 111b obtains the distance from the ultrasonic sonar 100 to the target 130 based on the delay time received from the correlator 117b.

[0022] The signal generating circuit 112a generates an excitation signal in the frequency range fa as shown in FIG. 2A in response to an instruction from the CPU core 111a.

[0023] The signal generating circuit 112b generates an excitation signal in a frequency range fb as shown in Fig. 2A in response to an instruction from the CPU core 111b. The frequency range fa and the frequency range fb do not have overlapping bands.

[0024] The excitation signals generated by the signal generating circuit 112a and the signal generating circuit 112b are frequency modulated signals, for example chirp signals as shown in FIG. 2B.

[0025] The transmitting wave driving circuits 113a and 113b drive the electroacoustic transducers 114a and 114b in accordance with the excitation signals generated by the signal generating circuits 112a and 112b, respectively.

[0026] The electroacoustic transducer 114a has a resonance frequency fR1. The electroacoustic transducer 114a transmits an electric signal received from the wave transmission driving circuit 113a as an ultrasonic wave, and transmits an electric signal corresponding to the received ultrasonic wave to the wave reception amplification circuit 115a.

[0027] Here, the resonant frequency fR1 is included in the frequency range fa, and may be the center frequency of the frequency range fa.

[0028] The electroacoustic transducer 114a is configured to receive a reflected signal 142 in the frequency range fa and a crossover signal 143 in the frequency range fb, and is therefore capable of receiving signals in both frequency ranges.

[0029] The electroacoustic transducer 114b has a resonance frequency fR2. The electroacoustic transducer 114b transmits an electric signal received from the transmitting wave driving circuit 113b as an ultrasonic wave, and transmits an electric signal corresponding to the received ultrasonic wave to the receiving wave amplifying circuit 115b.

[0030] Here, the resonant frequency fR2 is included in the frequency range fb, and may be the center frequency of the frequency range fb.

[0031] The electroacoustic transducer 114b is configured to receive a reflected signal 152 in the frequency range fb and a crossover signal 153 in the frequency range fa, and is therefore capable of receiving signals in both frequency ranges.

[0032] The receiving amplifier circuits 115a and 115b amplify the signals received from the electroacoustic transducers 114a and 114b, respectively. A low noise amplifier (LNA) can be used for the amplification.

[0033] The detectors 116a and 116b detect the signals received from the receiving amplifier circuits 115a and 115b, respectively. The detectors 116a and 116b may obtain the amplitude of the signals by, for example, envelope detection. The detectors 116a and 116b may obtain the amplitude and phase of the signals by, for example, converting the signals into baseband signals by quadrature detection.

[0034] The correlators 117a and 117b each obtain the transmitted signal as a reference signal and calculate the correlation with the received signal to obtain the delay time of the reflected signal 142 and the crossover signal 143.

[0035] The delay time from when the transmitted wave signal 141 from the electroacoustic transducer 114a is received as a reflected signal 142 is the time required for the signal to travel a round trip from the electroacoustic transducer 114a to the target. Therefore, the CPU core 111a can obtain the distance from the electroacoustic transducer 114a to the target 130 based on the delay time of the reflected signal 142.

[0036] In addition, the delay time until the transmission signal 151 transmitted by the electroacoustic transducer 114b is received as a crossing signal 143 is the time required for the signal to propagate the total distance consisting of the distance from the electroacoustic transducer 114b to the target 130 and the distance from the target 130 to the electroacoustic transducer 114a.

[0037] Therefore, the CPU core 111a can obtain the total distance of the distance from the electroacoustic transducer 114b to the target 130 and the distance from the target 130 to the electroacoustic transducer 114a based on the delay time of the crossover signal 143.

[0038] Similarly, the CPU core 111 b can obtain the distance from the electroacoustic transducer 114 b to the target 130 based on the delay time of the reflected signal 152 .

[0039] Furthermore, the CPU core 111b can obtain the total distance of the distance from the electroacoustic transducer 114a to the target 130 and the distance from the target 130 to the electroacoustic transducer 114b, based on the delay time of the crossover signal 153.

[0040] Sonar 120 has the same configuration as sonar 110, except that the resonant frequency and the frequency band of the excitation signal are different from those of sonar 110.

[0041] As described above, the electroacoustic transducer 114a having the resonant frequency fR1 of the sonar 110 is excited by an excitation signal in the frequency range fa. The electroacoustic transducer 114b having the resonant frequency fR2 of the sonar 120 is excited by an excitation signal in the frequency range fb. Here, the frequency range fb and the frequency range fa do not overlap because they are in different frequency domains.

[0042] Therefore, the frequency ranges of the ultrasonic signals transmitted by the sonars 110 and 120 are different and do not overlap, so interference between the ultrasonic signals can be prevented, and deterioration of the correlation gain when calculating the delay time can be prevented. As a result, deterioration of the detection accuracy of the target can be prevented.

[0043] (Embodiment 2) The circuit configuration of the ultrasonic sonar 300 according to the second embodiment of the present disclosure will be described.

[0044] The configuration of the second embodiment is a modification of the configuration of the first embodiment shown in Fig. 1 so that calculations and control are performed collectively by one microprocessor 318. The same components as those in Fig. 1 are given the same reference numerals and the description thereof will be omitted.

[0045] In FIG. 3, the ultrasonic sonar 300 has a CPU core 311, signal generating circuits 112a and 112b, transmitting wave driving circuits 113a and 113b, electroacoustic transducers 114a and 114b, a receiving wave amplifying circuit 315, a wave detector 316, and correlators 117a and 117b.

[0046] The CPU core 311 , the signal generating circuits 112 a and 112 b , the detector 316 , and the correlators 117 a and 117 b may be configured in a microprocessor 318 .

[0047] The CPU core 311 determines the position of the target based on the delay times received from the correlators 117a and 117b.

[0048] The electroacoustic transducer 114a has a resonant frequency fR1. The resonant frequency fR1 is included in a frequency range fa. The resonant frequency fR1 may be the center frequency of the frequency range fa.

[0049] The electroacoustic transducer 114b has a resonant frequency fR2. The resonant frequency fR2 is included in a frequency range fb. The resonant frequency fR2 may be the center frequency of the frequency range fb.

[0050] The electroacoustic transducers 114 a and 114 b output, to the receiving amplifier circuit 315 , electrical signals based on the received ultrasonic waves.

[0051] The receiving amplifier circuit 315 amplifies the signals received from the electroacoustic transducers 114a and 114b and outputs the amplified signals to the detector 316. An LNA can be used for the amplification.

[0052] The detector 316 detects the signal received from the receiving amplifier circuit 315. When a spread spectrum signal is transmitted, the signal may be despread using the spreading code used for the spread spectrum.

[0053] Detector 316 distributes the output between correlators 117a and 117b depending on whether a signal in frequency range fa or a signal in frequency range fb is detected.

[0054] The delay time from when the transmitted wave signal 141 transmitted by the electroacoustic transducer 114a is received as a reflected signal 142 is the time required for the signal to travel a round trip distance from the electroacoustic transducer 114a to the target 130. Therefore, the CPU core 311 can obtain the distance from the electroacoustic transducer 114a to the target 130 from the delay time of the reflected signal 142.

[0055] Furthermore, the delay time until the transmission signal 151 transmitted by the electroacoustic transducer 114b is received by the electroacoustic transducer 114a as the crossing signal 143 is the time required for the signal to propagate the total distance from the electroacoustic transducer 114b to the target 130 and the distance from the target 130 to the electroacoustic transducer 114a. Therefore, the CPU core 311 can obtain the total distance from the electroacoustic transducer 114b to the target 130 and the distance from the target 130 to the electroacoustic transducer 114a.

[0056] In addition, the delay time until the transmitted signal 151 sent by the electroacoustic transducer 114b is received as a reflected signal 152 is the time required for the signal to travel the round trip distance from the electroacoustic transducer 114b to the target 130, and therefore the distance from the electroacoustic transducer 114b to the target 130 can be obtained.

[0057] Furthermore, the delay time until the transmission signal 141 transmitted by the electroacoustic transducer 114a is received by the electroacoustic transducer 114b as a crossing signal 153 is the time required for the signal to propagate the total distance from the electroacoustic transducer 114a to the target 130 and the distance from the target 130 to the electroacoustic transducer 114b. Therefore, the CPU core 311 can obtain the total distance from the electroacoustic transducer 114a to the target 130 and the distance from the target 130 to the electroacoustic transducer 114b.

[0058] When the ultrasonic sonar 300 is mounted on a vehicle, the target 130 is located at approximately the same height as the vehicle. Since the distance between the electroacoustic transducer 114a and the electroacoustic transducer 114b is known, the CPU core 311 can obtain the position of the target 130 from this distance, the distance between the electroacoustic transducer 114a and the target 130, and the distance between the electroacoustic transducer 114b and the target 130.

[0059] (Embodiment 3) The circuit configuration of the system according to the third embodiment of the present disclosure will be described.

[0060] In Fig. 4, the configuration of the third embodiment is a modification of the configuration of the first embodiment shown in Fig. 1 so that an ECU (Electronic Control Unit) 460 performs calculations and control. The same components as those in Fig. 1 are given the same reference numerals and descriptions thereof will be omitted.

[0061] In the system of the third embodiment, the ECU 460 controls the sonars 410 and 420 .

[0062] The sonar 410 includes a CPU core 411a, a signal generating circuit 112a, a transmitting drive circuit 113a, an electroacoustic transducer 114a, a receiving amplifier circuit 115a, a detector 116a, and a correlator 117a. The CPU core 411a, the signal generating circuit 112a, the detector 116a, and the correlator 117a may be configured by a microprocessor 418a.

[0063] The sonar 420 includes a CPU core 411b, a signal generating circuit 112b, a transmitting drive circuit 113b, an electroacoustic transducer 114b, a receiving amplifier circuit 115b, a detector 116b, and a correlator 117b. The CPU core 411b, the signal generating circuit 112b, the detector 116b, and the correlator 117b may be configured by a microprocessor 418b.

[0064] The CPU cores 411 a and 411 b detect the delay times and peak value levels of the reflected signals 142 and 152 and the crossover signals 143 and 153 , and output the detected delay times and peak value levels to the ECU 460 .

[0065] The ECU 460 controls the transmission and reception frequency range and transmission timing of the sonars 410 and 420. The ECU 460 also detects the position of the target 130 based on the delay time detected by the CPU cores 411a and 411b.

[0066] (Embodiment 4) A circuit configuration of a system according to the fourth embodiment of the present disclosure will be described.

[0067] In Fig. 5, the configuration of the fourth embodiment is a modification of the configuration of the second embodiment shown in Fig. 3 so that ECU 560 performs calculations and control. The same components as those in Fig. 3 are given the same reference numerals and descriptions thereof will be omitted.

[0068] In the system of the fourth embodiment, the ECU 560 controls the ultrasonic sonar 500 .

[0069] The ultrasonic sonar 500 includes a CPU core 511, signal generating circuits 112a and 112b, transmitting drive circuits 113a and 113b, electroacoustic transducers 114a and 114b, a receiving amplifier circuit 315, a detector 316, and correlators 117a and 117b.

[0070] The CPU core 511, the signal generating circuits 112a and 112b, the detector 316, and the correlators 117a and 117b may be configured as a microprocessor 518.

[0071] The CPU core 511 detects the delay time and peak value level of the reflected signals 142 and 152 and the crossover signals 143 and 153 , and outputs the detected delay time and peak value level to the ECU 560 .

[0072] The ECU 560 controls the transmission and reception frequency range and transmission timing of the ultrasonic signal transmitted by the ultrasonic sonar 500. In addition, the ECU 560 detects the position of the target 130 based on the delay time detected by the CPU core 511.

[0073] (Embodiment 5) The circuit configuration of the ultrasonic sonar 600 according to the fifth embodiment of the present disclosure will be described.

[0074] In Fig. 6, the configuration of the fifth embodiment is obtained by providing variable BPFs (Band Pass Filters) 619a and 619b to the configuration of the first embodiment shown in Fig. 1. The same components as those in Fig. 1 are given the same reference numerals and the description thereof will be omitted.

[0075] The sonar 610 includes a CPU core 611a, a signal generating circuit 112a, a transmitting drive circuit 113a, a variable BPF (Band Pass Filter) 619a, an electroacoustic transducer 114a, a receiving amplifier circuit 115a, a detector 116a, and a correlator 117a. The CPU core 111a, the signal generating circuit 112a, the detector 116a, and the correlator 117a may be configured by a microprocessor 118a.

[0076] The sonar 620 includes a CPU core 611b, a signal generating circuit 112b, a transmitting drive circuit 113, a variable BPF 619b, an electroacoustic transducer 114b, a receiving amplifier circuit 115b, a detector 116b, and a correlator 117b. The CPU core 111b, the signal generating circuit 112b, the detector 116b, and the correlator 117b may be configured by a microprocessor 118b.

[0077] The variable BPFs 619a and 619b control the passband of the excitation signal under the control of the CPU cores 611a and 611b, respectively. The variable BPFs 619a and 619b may be digital filters whose tap coefficients are set by the CPU cores 611a and 611b, for example.

[0078] The CPU core 611a controls the entire sonar 610. The CPU core 611a instructs the signal generating circuit 112a to generate a signal to be transmitted. The CPU core 611a also controls the variable BPF 619a.

[0079] Furthermore, when the peak value detected after correlation detection by the correlator 117a is lower than the reference level, the CPU core 611a determines that there is mutual interference between the ultrasonic signals, and controls the passband of the excitation signal in the variable BPF 619a so that the peak value becomes higher than the reference level. The reference level of the peak value may be a constant level, or may be determined according to the distance to the target 130.

[0080] The CPU core 611 a can obtain the distance from the electroacoustic transducer 114 a to the target 130 based on the delay time of the reflected signal 142 .

[0081] In addition, the delay time until the transmission signal 151 transmitted by the electroacoustic transducer 114b is received as the crossing signal 143 is the time it takes for the signal to propagate the total distance between the distance from the electroacoustic transducer 114b to the target 130 and the distance from the target 130 to the electroacoustic transducer 114a.

[0082] Therefore, the CPU core 611a can obtain the total distance of the distance from the electroacoustic transducer 114b to the target 130 and the distance from the target 130 to the electroacoustic transducer 114a based on the delay time of the crossover signal 143.

[0083] The CPU core 611b controls the entire sonar 620. The CPU core 111b instructs the signal generating circuit 112b to generate a signal to be transmitted. The CPU core 611b also controls the variable BPF 619b.

[0084] When the peak value detected after correlation detection by the correlator 117b is lower than the reference level, the CPU core 611b determines that there is mutual interference between the ultrasonic signals, and controls the passband of the excitation signal in the variable BPF 619b so that the peak value becomes higher than the reference level. The reference level of the peak value may be a constant level or may be determined according to the distance to the target 130.

[0085] The CPU core 611 b can obtain the distance from the electroacoustic transducer 114 b to the target 130 based on the delay time of the reflected signal 152 .

[0086] In addition, the delay time until the transmission signal 141 transmitted by the electroacoustic transducer 114a is received as a crossover signal 153 is the time it takes for the signal to propagate the total distance of the distance from the electroacoustic transducer 114a to the target 130 and the distance from the target 130 to the electroacoustic transducer 114b.

[0087] Therefore, the CPU core 611b can obtain the total distance of the distance from the electroacoustic transducer 114a to the target 130 and the distance from the target 130 to the electroacoustic transducer 114b based on the delay time of the crossover signal 153.

[0088] Sonar 620 has the same configuration as sonar 110 except that it has a different resonant frequency and a different frequency band of the excitation signal from sonar 610.

[0089] (Embodiment 6) The circuit configuration of the ultrasonic sonar 700 according to the sixth embodiment of the present disclosure will be described.

[0090] In Fig. 7, the configuration of the sixth embodiment is obtained by providing variable BPFs 619a and 619b to the configuration of the second embodiment shown in Fig. 3. The same components as those in Fig. 3 are given the same reference numerals and the description thereof will be omitted.

[0091] The ultrasonic sonar 700 includes a CPU core 711, signal generating circuits 112a and 112b, transmitting drive circuits 113a and 113b, variable BPFs 619a and 619b, electroacoustic transducers 114a and 114b, a receiving amplifier circuit 315, a detector 316, and correlators 117a and 117b.

[0092] The CPU core 711 , the signal generating circuits 112 a and 112 b , the detector 316 , and the correlators 117 a and 117 b may be configured as a microprocessor 718 .

[0093] The CPU core 711 obtains the position of the target based on the delay times received from the correlators 117a and 117b. The CPU core 711 controls the variable BPFs 619a and 619b.

[0094] When the peak value detected after correlation detection by the correlators 117a and 117b is lower than the reference level, the CPU core 711 determines that there is mutual interference between the ultrasonic signals, and controls the band of the excitation signal in the variable BPFs 619a and 619b so that the peak value becomes higher than the reference level. The reference level of the peak value may be a constant level, or may be determined according to the distance to the target 130.

[0095] (Embodiment 7) The circuit configuration of the system according to the seventh embodiment of the present disclosure will be described.

[0096] In Fig. 8, the configuration of the seventh embodiment is obtained by providing a variable BPF to the configuration of the third embodiment shown in Fig. 4. The same components as those in Fig. 4 are given the same reference numerals and the description thereof will be omitted.

[0097] In the system of the seventh embodiment, the ECU 860 controls the sonars 810 and 820 .

[0098] The sonar 810 includes a CPU core 811a, a signal generating circuit 112a, a transmitting drive circuit 113a, a variable BPF 619a, an electroacoustic transducer 114a, a receiving amplifier circuit 115a, a detector 116a, and a correlator 117a. The CPU core 811a, the signal generating circuit 112a, the detector 116a, and the correlator 117a may be configured by a microprocessor 818a.

[0099] The sonar 820 includes a CPU core 811b, a signal generating circuit 112b, a transmitting drive circuit 113b, an electroacoustic transducer 114b, a receiving amplifier circuit 115b, a detector 116b, and a correlator 117b. The CPU core 811b, the signal generating circuit 112b, the detector 116b, and the correlator 117b may be configured by a microprocessor 818b.

[0100] The CPU cores 811a and 811b detect the delay time and peak value level of the reflected signals 142 and 152 and the crossover signals 143 and 153, and output the detected delay time and peak value level to the ECU 860. In addition, the CPU cores 811a and 811b control the variable BPFs 619a and 619b under the control of the ECU 860.

[0101] The ECU 860 controls the transmission and reception frequency ranges and transmission timings of ultrasonic signals transmitted by the sonars 810 and 820. The ECU 860 also detects the position of the target 130 based on the delay times detected by the CPU cores 811a and 811b.

[0102] When the detected peak value is lower than the reference level, the ECU 860 determines that there is mutual interference between the ultrasonic signals, and causes the CPU cores 811a and 811b to control the passband of the excitation signal in the variable BPFs 619a and 619b so that the peak value becomes higher than the reference level. The reference level of the peak value is determined according to the distance to the target 130.

[0103] (Embodiment 8) The circuit configuration of the system according to the eighth embodiment of the present disclosure will be described.

[0104] In Fig. 9, the configuration of the eighth embodiment is obtained by providing variable BPFs 619a and 619b to the configuration of the fourth embodiment shown in Fig. 5. The same components as those in Fig. 5 are given the same reference numerals and the description thereof will be omitted.

[0105] In the system of the eighth embodiment, the ECU 960 controls the ultrasonic sonar 900 .

[0106] The ultrasonic sonar 900 includes a CPU core 911, signal generating circuits 112a and 112b, transmitting drive circuits 113a and 113b, variable BPFs 619a and 619b, electroacoustic transducers 114a and 114b, a receiving amplifier circuit 315, a detector 316, and correlators 117a and 117b.

[0107] The CPU core 911 , the signal generating circuits 112 a and 112 b , the detector 316 , and the correlators 117 a and 117 b may be configured in a microprocessor 918 .

[0108] Based on the delay times received from the correlators 117a and 117b, the CPU core 911 obtains the position of the target 130. Based on the control of the ECU 960, the CPU core 911 controls the variable BPFs 619a and 619b.

[0109] The ECU 960 controls the transmission and reception frequency range and transmission timing of the ultrasonic sonar 900. In addition, the ECU 960 detects the position of the target 130 based on the delay time detected by the CPU core 911.

[0110] When the detected peak value is lower than the reference level, the ECU 960 determines that there is mutual interference between the ultrasonic signals, and causes the CPU core 911 to control the passband of the excitation signal in the variable BPFs 619a and 619b so that the peak value becomes higher than the reference level. The reference level of the peak value may be a constant level, or may be determined according to the distance to the target 130.

[0111] <Modification> In the configurations of the fifth to eighth embodiments shown in FIGS. 6 to 9, wideband electroacoustic transducers having different resonant frequencies may be used as the electroacoustic transducers 114a and 114b, and the variable BPFs 619a and 619b may be controlled so that the frequency ranges fa and fb of the excitation signals do not overlap.

[0112] <Reference value> FIG. 10 shows a reference value for determining whether or not to control the variable BPFs 619a and 619b.

[0113] The detected peak value in the sonar is given as the sum of the peak value of the transmitted signal and the correlation gain minus the loss.

[0114] In FIG. 10, the dotted line indicates a case where there is interference between the ultrasonic signals transmitted from the two electroacoustic transducers, resulting in a low correlation gain and a peak value that is less than the reference value, while the solid line indicates a case where there is no interference between the ultrasonic signals, resulting in a high correlation gain and a peak value that is higher than the reference value.

[0115] In this example, the reference value is determined according to the distance to the target, and for example, the reference value decreases as the distance increases. The reference value may be determined according to the ambient temperature, or may be determined according to the ambient temperature and the distance. The reference value may be a constant reference value regardless of the distance.

[0116] <Initial settings> Fig. 11 shows a system for adjusting the initial settings of the ultrasonic sonars in the first to eighth embodiments at the time of shipment from a factory, etc. Fig. 12 shows a system for simultaneously adjusting the initial settings of two ultrasonic sonars. Fig. 12 shows the system as viewed from above.

[0117] For example, a cylindrical target with a diameter of 75 mm is placed 1 m ahead of the sonar. A PC (Personal Computer) that replaces the ECU controls the ultrasonic sonar, detects the wave height of the reflected signal from the target, and adjusts the ultrasonic sonar's variable BPF, transmitted sound pressure, receiving sensitivity, etc. depending on whether the wave height is higher or lower than the reference value.

[0118] The flow of the adjustment process of the initial settings in the first to fourth embodiments will be described with reference to FIG.

[0119] First, the PC reads initial parameters as default parameters (step S1301). The default parameters are, for example, the frequency, sound pressure, and wave receiving sensitivity of the ultrasonic signal to be transmitted.

[0120] After reading the initial parameters, the PC controls the ultrasonic sonar to transmit waves (step S1302).

[0121] Then, the PC determines whether or not the peak value of the received reflected signal is equal to or greater than a reference value (step S1303).

[0122] In step S1303, if the peak value of the received reflected signal is equal to or greater than the reference value, no adjustment is made and the process ends.

[0123] In step S1303, if the peak value of the received reflected signal is less than the reference value, the PC adjusts the sound pressure (step S1304).

[0124] Thereafter, the PC determines whether or not the peak value of the received reflected signal is equal to or greater than a reference value (step S1305).

[0125] In step S1305, if the peak value of the received reflected signal is equal to or greater than the reference value, no further adjustment is made and the process ends.

[0126] In step S1305, if the peak value of the received reflected signal is less than the reference value, the PC adjusts the wave receiving sensitivity (step S1306).

[0127] Then, the PC determines whether or not the peak value of the received reflected signal is equal to or greater than a reference value (step S1307).

[0128] In step S1307, if the peak value of the received reflected signal is equal to or greater than the reference value, no further adjustment is made and the process ends.

[0129] In step S1307, if the peak value of the received reflected signal is less than the reference value, even if all parameters are adjusted, a reflected signal having a peak value equal to or greater than the reference value is not received, so the PC determines that the sonar is defective and the process ends.

[0130] The flow of the adjustment process of the initial settings in the fifth to eighth embodiments will be described with reference to FIG.

[0131] The processing from steps S1301 to S1307 is the same as the processing from steps S1301 to S1307 shown in FIG.

[0132] In step S1307, if the crest value of the received reflected signal is less than the reference value, the PC performs adjustment to avoid interference (step S1408). The adjustment to avoid interference is to adjust the variable BPF. The adjustment of the variable BPF may be an adjustment of the half-width.

[0133] Thereafter, the PC determines whether or not the peak value of the received reflected signal is equal to or greater than a reference value (step S1409).

[0134] In step S1409, if the peak value of the received reflected signal is equal to or greater than the reference value, no further adjustment is made and the process ends.

[0135] In step S1409, if the peak value of the received reflected signal is less than the reference value, the PC determines that the sonar is defective since no reflected signal having a peak value equal to or greater than the reference value is received even if all parameters are adjusted, and the process ends.

[0136] <Example of sonar installed on a vehicle> For example, each sonar included in the ultrasonic sonar may be disposed at the front, side, and rear of the vehicle. Also, each sonar may be disposed at approximately the corners of the vehicle.

[0137] In the example shown in FIG. 15, the two sonars are driven simultaneously to detect the reflected signal and the crossover signal simultaneously.

[0138] Specifically, sonar 1 having a resonant frequency fR1 and sonar 2 having a resonant frequency fR2 different from the resonant frequency fR1 transmit simultaneously. Then, sonars 1 and 2 receive the reflected signal of the signal transmitted by their own sonar and the crossover signal transmitted by the other sonar.

[0139] In FIG. 16, the three sonars are arranged such that sonar 1 and sonar 3, each having a resonant frequency fr1, are disposed on either side, and sonar 2, having a resonant frequency fR2, is disposed in the center.

[0140] Of the three sonars, two are driven simultaneously. For example, the pairs of two sonars that are driven simultaneously are "Sonar 1 and Sonar 2" and "Sonar 2 and Sonar 3", and these two pairs are driven alternately. The sonars that are not driven simultaneously detect the migration signal.

[0141] In this case, since sonar 1 and sonar 3 do not transmit waves at the same time, one signal generating circuit can be provided for each of them, and the output destination of the one signal generating circuit can be switched to a transmitting wave driving circuit connected to the electro-acoustic transducer that drives sonar 1 or sonar 3.

[0142] In FIG. 17, when there are four sonars, sonars 1 and 3 with resonant frequencies fR1 and sonars 2 and 4 with resonant frequencies fR2 are arranged alternately.

[0143] Of the four sonars, two are driven simultaneously. There are three pairs of two sonars that are driven simultaneously: "Sonar 2 and Sonar 3", "Sonar 1 and Sonar 2", and "Sonar 3 and Sonar 4", and these three pairs are driven repeatedly in this order. The sonars that are not driven simultaneously detect the migration signal.

[0144] In FIG. 17, since sonar 1 and sonar 4 are far apart, the crossover signal between sonar 1 and sonar 4 is not received, but the crossover signal between sonar 1 and sonar 4 may also be received.

[0145] In this case, since sonar 1 and sonar 3 do not transmit waves at the same time, one signal generating circuit can be provided for each of them, and the output destination of the one signal generating circuit can be switched to a transmitting wave driving circuit connected to the electro-acoustic transducer that drives sonar 1 or sonar 3.

[0146] In addition, since sonar 2 and sonar 4 do not transmit waves at the same time, one signal generating circuit can be provided for each of them, and the output destination of the one signal generating circuit can be switched to a transmitting wave driving circuit connected to the electro-acoustic transducer that drives sonar 2 or sonar 4.

[0147] In FIG. 18, sonars 1 and 3 having a resonant frequency fR1 and sonars 2 and 4 having a resonant frequency fR2 are arranged alternately.

[0148] Of the four sonars, two are driven simultaneously. The two pairs of two sonars that are driven simultaneously are "Sonar 2 and Sonar 3" and "Sonar 1 and Sonar 4", and these pairs are driven alternately. The sonars that are not driven simultaneously detect the crossing signal. In FIG. 18, the distance between sonar 1 and sonar 4 is far, so the crossing signal between sonar 1 and sonar 4 is not the target for reception, but the crossing signal between sonar 1 and sonar 4 may be the target for reception.

[0149] 18, sonar 1 and sonar 2, sonar 1 and sonar 3, sonar 2 and sonar 4, and sonar 3 and sonar 4 do not transmit simultaneously. Therefore, one signal generating circuit is provided for each pair, and the output destination of one signal generating circuit may be switched to the sonar wave transmitting driving circuit connected to the electro-acoustic transducer to be driven.

[0150] In FIG. 19, of the sonars with resonant frequencies fR1 and fR2, the two sonars 1 and 4 with resonant frequency fR1 are arranged on the outside of the vehicle, and the two sonars 2 and 3 with resonant frequency fR2 are arranged closer to the center of the vehicle.

[0151] Of the four sonars, two are driven simultaneously. The two pairs of two sonars that are driven simultaneously are "Sonar 1 and Sonar 2" and "Sonar 3 and Sonar 4", and these pairs are driven alternately. The sonars that are not driven simultaneously detect the migration signal. In FIG. 19, the distance between sonar 1 and sonar 4 is far, so the migration signal between sonar 1 and sonar 4 is not the target for reception, but the migration signal between sonar 1 and sonar 4 may be the target for reception.

[0152] 19, sonar 1 and sonar 3, sonar 1 and sonar 4, sonar 2 and sonar 3, and sonar 2 and sonar 4 do not transmit simultaneously. Therefore, one signal generating circuit is provided for each pair, and the output destination of one signal generating circuit may be switched to the sonar wave transmitting driving circuit connected to the electro-acoustic transducer to be driven.

[0153] In FIG. 20, of the sonars with resonant frequencies fR1 and fR2, the two sonars 1 and 4 with resonant frequency fR1 are positioned closer to the side of the vehicle than sonars 2 and 3, and the two sonars 3 and 4 with resonant frequency fR2 are positioned closer to the center of the vehicle than sonars 1 and 4.

[0154] Of the four sonars, two are driven simultaneously. There are two pairs of two sonars that are driven simultaneously: "Sonar 1 and Sonar 3" and "Sonar 2 and Sonar 4", and these pairs are driven alternately. The sonars that are not driven simultaneously detect the crossing signal. In FIG. 20, the distance between sonar 1 and sonar 4 is far, so the crossing signal between sonar 1 and sonar 4 is not the target for reception, but the crossing signal between sonar 1 and sonar 4 may be the target for reception.

[0155] In this case, sonar 1 and sonar 2, sonar 1 and sonar 4, sonar 2 and sonar 3, and sonar 3 and sonar 4 do not transmit simultaneously. Therefore, one signal generating circuit is provided for each pair, and the output destination of the one signal generating circuit may be switched to the sonar transmission wave driving circuit connected to the electro-acoustic transducer to be driven.

[0156] In each of the above embodiments, when an ultrasonic sonar is mounted on a vehicle, the determined distance to the target 130 may be used to control the vehicle (for example, accelerator, brake, steering).

[0157] In the above-described embodiments, the notation "... device" used for each component may be replaced with other notations such as "... circuit", "... assembly", "... device", "... unit", or "... module".

[0158] The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiment may be realized partially or entirely as an LSI, which is an integrated circuit, and each process described in the above embodiment may be controlled partially or entirely by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include some or all of the functional blocks. The LSI may have input and output of data. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI.

[0159] The method of integration is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after LSI manufacturing, a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0160] Furthermore, if a new integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a derivative technology, it is possible to integrate the functional blocks using that technology. The application of biotechnology is also a possibility.

[0161] (1) A sonar in one aspect of the present disclosure includes a first transducer having a first resonant frequency, a first signal generating circuit that generates a first excitation signal having a first frequency range that excites the first transducer, a second transducer having a second resonant frequency different from the first resonant frequency, and a second signal generating circuit that generates a second excitation signal having a second frequency range that excites the second transducer, the second frequency range different from the first frequency range.

[0162] (2) In one aspect of the present disclosure, in the sonar of (1), the first transducer and the second transducer each receive both the first frequency range and the second frequency range.

[0163] (3) A sonar according to one aspect of the present disclosure is the sonar of (1), further comprising one CPU core that controls both the first signal generating circuit and the second signal generating circuit.

[0164] (4) A sonar according to one aspect of the present disclosure is the sonar of (1), further including an ECU that detects a target based on ultrasonic waves received by the first transducer and the second transducer.

[0165] (5) A sonar according to one aspect of the present disclosure is the sonar of (1), further comprising a first variable bandpass filter for varying the range of ultrasonic waves transmitted from the first transducer, and a second variable bandpass filter for varying the range of ultrasonic waves transmitted from the second transducer.

[0166] (6) A sonar in one aspect of the present disclosure is the sonar described in (1), further comprising a third sonar having a third transducer having the first resonant frequency.

[0167] (7) A sonar in one aspect of the present disclosure is the sonar described in (6), further comprising a fourth sonar having a fourth transducer having the second resonant frequency.

[0168] (8) A vehicle in one embodiment of the present disclosure is equipped with a sonar described in any one of (1) to (7). [Industrial Applicability]

[0169] The present disclosure is useful in sonar and vehicles. [Explanation of symbols]

[0170] 100, 300, 500, 600, 700, 900 Ultrasonic Sonar 110, 120, 410, 420, 610, 620, 810, 820 Sonar 111a, 111b, 311, 411a, 411b, 511, 611a, 611b, 711, 811a, 811b, 911 CPU cores 112a, 112b signal generation circuit 113a, 113b Wave transmission drive circuit 114a, 114b Electroacoustic transducer 115a, 115b, 315 receiving amplifier circuit 116a, 116b, 316 detector 117a, 117b Correlator 118a, 118b, 318, 418a, 418b, 518, 618a, 618b, 718, 818a, 818b, 918 Microprocessors 130 Target 141, 151 Transmission signal 142, 152 reflected signal 143, 153 Crossing Signal 460, 560, 860, 960 ECU 619a, 619b Variable BPF

Claims

1. a first transducer having a first resonant frequency; a first signal generating circuit for generating a first excitation signal having a first frequency range for exciting the first transducer; a second transducer having a second resonant frequency different from the first resonant frequency; a second signal generating circuit for generating a second excitation signal having a second frequency range different from the first frequency range for exciting the second transducer; Sonar equipped with

2. the first transducer and the second transducer each receive both the first frequency range and the second frequency range; The sonar of claim 1.

3. Further comprising one CPU core that controls both the first signal generating circuit and the second signal generating circuit. The sonar of claim 1.

4. The vehicle further includes an ECU that detects a target based on ultrasonic waves received by the first transducer and the second transducer. The sonar of claim 1.

5. Further comprising a first variable bandpass filter for varying the range of ultrasonic waves transmitted from the first transducer, and a second variable bandpass filter for varying the range of ultrasonic waves transmitted from the second transducer. The sonar of claim 1.

6. a third sonar having a third transducer having the first resonant frequency; The sonar of claim 1.

7. a fourth sonar having a fourth transducer having the second resonant frequency; 7. The sonar of claim 6.

8. A vehicle equipped with the sonar according to claim 1.

Images