Sonar device and object detection method

Abstract

To provide a sonar device capable of solving the problem that when receiving ultrasonic signals multiple times, the ultrasonic signals interfere with each other, and the received power of the synthesized ultrasonic signal may decrease.SOLUTION: The sonar device includes: a transmission circuit that transmits transmission signals of multiple frequencies; a receiving circuit that receives reception signals corresponding to the transmitted signals of the multiple frequencies; and a detection circuit that detects objects based on the received signal. The multiple frequencies are determined so that the power of a composite signal of received signals that have at least one frequency among the multiple frequencies is greater than that of each received signal constituting the composite signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to sonar devices and object detection methods. [Background technology]

[0002] In recent years, vehicles have been equipped with various sensors, such as sonar devices. Sonar devices can detect the presence of an object (also called a target) by transmitting an ultrasonic signal and receiving the ultrasonic signal reflected by the object, and can also measure the distance to the object from the time difference between the time the signal is transmitted and the time it is received.

[0003] For objects with simple shapes, such as walls, when an ultrasonic signal is reflected by the object, the sonar device receives a single strong received signal.

[0004] On the other hand, in the case of an object with a complex shape, such as a human, the ultrasonic signal is reflected from multiple points on the object, so the sonar receives the signal multiple times. Also, if there are multiple objects, the sonar receives the ultrasonic signal multiple times.

[0005] When ultrasonic signals are received multiple times, the ultrasonic signals may interfere with each other, potentially reducing the received power of the combined ultrasonic signal. For example, if a "sparse" ultrasonic signal and a "dense" ultrasonic signal overlap, the received power of the combined ultrasonic signal will be weak, making it difficult to receive the ultrasonic signal properly.

[0006] For example, if the difference (distance difference) between the first path length when the first reflected wave is received and the second path length when the second reflected wave is received is half a wavelength, the "sparse" and "dense" ultrasonic signals will be combined, making it difficult to receive the ultrasonic signals properly.

[0007] Patent Document 1 discloses a technique for reducing interference between ultrasonic signals by using chirp signals as transmission signals, while Patent Document 2 discloses a technique for reducing interference between ultrasonic signals by simultaneously transmitting ultrasonic signals of two different frequencies. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2022 / 176442 [Patent Document 2] Japanese Patent Application Publication No. 2019-035755 [Patent Document 3] International Publication No. 2021 / 256414 Summary of the Invention [Problem to be solved by the invention]

[0009] However, neither of these documents takes into consideration interference of ultrasonic signals reflected by multiple objects, and the frequency difference is small, so interference prevention is insufficient.

[0010] Non-limiting examples of the present disclosure contribute to providing a sonar device and an object detection method that can reduce interference between ultrasonic signals. [Means for solving the problem]

[0011] A sonar device in one embodiment of the present disclosure comprises a transmitting circuit that transmits transmission signals of multiple frequencies, a receiving circuit that receives reception signals corresponding to the transmission signals of the multiple frequencies, and a detection circuit that detects an object based on the reception signals, wherein the multiple frequencies are determined so that the power of a composite signal of reception signals having at least one frequency from the multiple frequencies is greater than the power of each of the reception signals that make up the composite signal.

[0012] In one embodiment of the present disclosure, a vehicle is equipped with a sonar device that includes a transmitting circuit that transmits transmission signals of multiple frequencies, a receiving circuit that receives reception signals corresponding to the transmission signals of the multiple frequencies, and a detection circuit that detects an object based on the reception signals, and the multiple frequencies are determined so that the power of a composite signal of reception signals having at least one frequency from the multiple frequencies is greater than the power of each of the reception signals that make up the composite signal.

[0013] An object detection method in one embodiment of the present disclosure is an object detection method that transmits transmission signals of multiple frequencies, receives reception signals corresponding to the transmission signals of the multiple frequencies, and detects an object based on the reception signals, wherein the multiple frequencies are determined so that the power of a composite signal of reception signals having at least one frequency from the multiple frequencies is greater than the power of each of the reception signals that make up the composite signal. [Effects of the Invention]

[0014] According to an embodiment of the present disclosure, interference between ultrasonic signals can be reduced. [Brief explanation of the drawings]

[0015] [Figure 1] Top view of the vehicle [Figure 2] Sonar device block diagram [Figure 3] Block diagram of a sonar device with two transducers [Figure 4] A diagram showing the received power versus the path difference when transmitting 31kHz ultrasonic waves. [Figure 5] A diagram showing the received power versus the path difference when transmitting 62kHz ultrasonic waves. [Figure 6] A diagram showing a situation where two adjacent transducers transmit and receive ultrasonic waves of frequency f1 and frequency f2, respectively. [Figure 7]A diagram showing two transducers at the same location transmitting and receiving ultrasonic signals at frequencies f1 and f2, respectively. [Figure 8] A diagram showing a situation in which two adjacent transducers simultaneously transmit an ultrasonic signal of frequency f1 or an ultrasonic signal of frequency f2, and both transducers receive the ultrasonic signal of frequency f1 and the ultrasonic signal of frequency f2. [Figure 9] A diagram showing a situation in which two transducers present at the same location simultaneously transmit an ultrasonic signal of frequency f1 or an ultrasonic signal of frequency f2, and both transducers receive the ultrasonic signals of frequency f1 and frequency f2. [Figure 10] A diagram showing a situation where a single transducer alternately transmits ultrasonic signals at frequencies f1 and f2. [Figure 11] A diagram showing an example of the difference in reception intensity between successive frames of a received signal. [Figure 12] FIG. 10 is a diagram showing an example of the relationship between the reception intensity of successive frames of a received signal and a threshold value. [Figure 13] A diagram showing an example of peaks in the received signal strength [Figure 14] FIG. 10 is a diagram showing an example of a time period during which the received signal strength is equal to or greater than a threshold value. [Figure 15] FIG. 10 is a diagram showing an example of a flowchart of a process for transmitting wave signals at multiple frequencies only when an object is determined to have a complex shape. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are merely examples, and the present disclosure is not limited to the following embodiments.

[0017] However, more detailed explanations than necessary may be omitted, for example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted, in order to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0019] In FIG. 1, a vehicle 100 includes sonar devices 111 to 118 and a vehicle control unit (ECU: Electronic Control Unit) 120.

[0020] Sonar device 111 is located on the front right (FR). Sonar device 112 is located in the front right center (FRC). Sonar device 113 is located in the front left center (FLC). Sonar device 114 is located on the front left (FL).

[0021] Also, sonar device 115 is located on the rear right side (Rear Right RR). Sonar device 116 is located in the rear right center (RRC). Sonar device 117 is located in the rear left center (RLC). Sonar device 118 is located on the rear left side (Rear Left RL). The number and locations of sonar devices are not limited to those shown in FIG. 1.

[0022] The ECU 120 is connected to the sonar devices 111 to 118. Based on the detection results of the sonar devices 111 to 118, the ECU 120 can control the vehicle, such as by applying an emergency brake or controlling the direction of travel of the vehicle.

[0023] The following describes in detail the configuration of the sonar devices 111-118 mounted on the vehicle 100. In FIG.

[0024] Sonar device 200 has a transmission control circuit 210, a detection circuit 220, and a sensor 230. Sensor 230 has a transmission circuit 231, a reception circuit 232, and a transducer 233. A vehicle may be equipped with multiple sonar devices, or may be equipped with other sonar devices.

[0025] The transmission control circuit 210 outputs the object detection result to the ECU 120. The transmission control circuit 210 controls the transmission circuit 231. The transmission control circuit 210 controls the timing at which the transmission circuit 231 transmits ultrasonic waves, the frequency of the transmitted ultrasonic signals, and the transmission time for transmitting the ultrasonic signals. The frequency of each transmitted ultrasonic signal is, for example, 62 kHz, 31 kHz, etc. Each ultrasonic signal may be a chirp signal. The transmission control circuit 210 sets the transmission time to, for example, 1 ms. When transmitting ultrasonic waves in pulses, the transmission control circuit 210 may set the number of pulses, for example, 64 pulses, and may further set the pulse width and pulse period.

[0026] The detection circuit 220 detects the received signal.

[0027] The transmission circuit 231 generates a transmission signal based on the control of the transmission control circuit 210 , and transmits the generated transmission signal to the transducer 233 .

[0028] The receiving circuit 232 transmits a received signal to the detection circuit 220 based on the received signal received by the transducer 233. The receiving circuit 232 may include a frequency filter, a Fourier transformer, and the like.

[0029] The transducer 233 is an electroacoustic transducer that transmits an ultrasonic signal based on a transmission signal received from the transmission circuit 231, and transmits a reception signal based on the received ultrasonic signal to the reception circuit 232. While it is difficult for the transducer 233 to receive an ultrasonic signal while transmitting it, it may receive the ultrasonic signal at the same time as transmitting it.

[0030] In FIG. 3, sonar device 300 is used as sonar devices 111-118.

[0031] Sonar device 300 has a transmission control circuit 310, detection circuits 220-1 and 220-2, and sensors 230-1 (sensor #1) and 230-2 (sensor #2). Detection circuits 220-1 and 220-2 may have the same configuration as detection circuit 220 in Fig. 2, and sensors #1 and #2 may have the same configuration as sensor 230 in Fig. 2. Sensors #1 and #2 may also be sensors with different configurations.

[0032] Furthermore, sensors #1 and #2 may be located in the same location, for example, on the front right side of the vehicle. Sensors #1 and #2 may be located adjacent to each other, for example, sensor #1 may be located on the front right side of the vehicle and sensor #2 may be located in the center of the front right side of the vehicle.

[0033] Other sonar devices may be installed on the vehicle 100. Also, both the sonar device 200 and the sonar device 300 may be installed on the vehicle 100.

[0034] Since the components other than the transmission control circuit 310 are the same as those in the first configuration, a description thereof will be omitted.

[0035] The transmission control circuit 310 outputs the results of detection by the detection circuits 220-1 and 220-2 to the ECU 120. Based on the object detection results, the ECU 120 can control the vehicle, such as by applying an emergency brake or controlling the direction of travel of the vehicle.

[0036] In Figures 4 and 5, the horizontal axis represents the path difference (distance difference) between the two reflected waves, and the received power of each of the two reflections is assumed to be equal. Figures 4(a) and 5(a) show the maximum power after combining up to a distance difference of 1000 mm.

[0037] In Figure 4, the frequency is 31 kHz, so the wavelength of the ultrasonic signal is approximately 11 mm. If the difference in distance from the sonar device to the two reflecting points is 2.75 mm, the round-trip path difference is 5.5 mm, resulting in a path difference equivalent to half a wavelength. When ultrasonic signals with a phase shift of half a wavelength are combined, the received power becomes weaker. From Figure 4(b), we can see that at a distance difference of 2.75 mm, the combined received power is approximately -18 dB.

[0038] In Figure 5, the frequency is 62 kHz, so the wavelength of the ultrasonic signal is approximately 5.5 mm. If the difference in distance from the sonar device to the two reflecting points is 2.75 mm, the round-trip path difference is 5.5 mm, resulting in a path difference of one wavelength. When ultrasonic signals with a phase shift of one wavelength are combined, the received power becomes stronger. From Figure 5(b), we can see that at a distance difference of 2.75 mm, the combined received power is approximately +6 dB.

[0039] Referring to Figures 4 and 5, when two ultrasonic signals are received with a difference of 2.75 mm in distance from the sonar device to the two reflecting points on the object, the combined received power is -18 dB for ultrasonic signals with a frequency of 31 kHz, which is weak, but the combined received power is +6 dB for ultrasonic signals with a frequency of 62 kHz, which is strong.

[0040] The combined received power of ultrasonic signals of frequency f weakens when the difference in path length between the ultrasonic signals is half a period. Even with the same path length difference, the path length difference becomes one period for an ultrasonic signal of frequency 2f, which has twice the frequency (half the wavelength). Therefore, when the combined received power of ultrasonic signals of frequency f weakens, the combined received power of ultrasonic signals of frequency 2f strengthens.

[0041] Therefore, by transmitting ultrasonic signals of frequency f and frequency 2f as the frequencies of the two ultrasonic signals to be transmitted, it is possible to obtain a combined received signal with strong received power for at least one of the ultrasonic signals.

[0042] Although the case where ultrasonic signals of frequency f and frequency 2f are transmitted has been described here, it is sufficient that the ultrasonic signal synthesized from ultrasonic signals of at least one frequency is strong. Also, it is sufficient that the multiple frequencies are determined so that the synthesized received wave power of ultrasonic signals of at least one frequency among the multiple frequencies is greater than the received wave power of each ultrasonic signal that makes up the synthesized received wave signal.

[0043] In Fig. 6, of the two transducers located adjacent to each other, transducer Tr1 transmits and receives ultrasonic waves at frequency f1, and transducer Tr2 transmits and receives ultrasonic waves at frequency f2. In Fig. 6, transducer Tr1 is located on the front right side of the vehicle, and transducer Tr2 is located in the center of the front right side of the vehicle.

[0044] In Figure 6, the ultrasonic signal of frequency f1 is shown by a solid line, and the ultrasonic signal of frequency f2 is shown by a dotted line (this also applies to Figures 7 to 10 described below). Frequency f2 is twice the frequency of frequency f1. Each frequency may be any frequency as long as the ultrasonic signal synthesized from ultrasonic signals of at least one frequency is strong.

[0045] For example, the transducers Tr1 and Tr2 may be the transducers 233 having the configuration shown in FIG. 2 and may be provided in the sonar devices 111 and 112, respectively.

[0046] In this case, the ECU 120 controls the transmission control circuit 210 of the sonar device 111, causing the sonar device 111 to transmit and receive ultrasonic signals of frequency f1. The ECU 120 also controls the transmission control circuit 210 of the sonar device 112, causing the sonar device 112 to transmit and receive ultrasonic signals of frequency f2. The transmission of waves by the sonar device 111 and the sonar device 112 is simultaneous.

[0047] The ECU 120 detects an object based on the received wave signal of frequency f1 received by the sonar device 111 and the received wave signal of frequency f2 received by the sonar device 112. At least one of the sonars can obtain a strong received wave signal, so the ECU 120 can detect an object based on the strong received wave signal.

[0048] Furthermore, the transducer Tr1 and the transducer Tr2 may be the transducers 233-1 and 233-2 having the configuration shown in FIG. 3, respectively, and may be provided at the front right side of the vehicle and at the center of the entire right side of the vehicle.

[0049] The transmission control circuit 310 may then cause the sensor #1 having the transducer Tr1 to transmit and receive ultrasonic signals of frequency f1, and the sensor #2 having the transducer Tr2 to transmit and receive ultrasonic signals of frequency f2. The transmission of the ultrasonic signals from the transducer Tr1 and the transducer Tr2 is simultaneous.

[0050] The transmission control circuit 310 detects an object based on the wave reception signal of frequency f1 received by the transducer Tr1 and the wave reception signal of frequency f2 received by the transducer Tr2. At least one of the transducers can obtain a strong wave reception signal, so the transmission control circuit 310 can detect an object based on the strong wave reception signal.

[0051] In Figure 7, of the two transducers located in the same location, transducer Tr1 transmits and receives ultrasonic signals at frequency f1, and transducer Tr2 transmits and receives ultrasonic signals at frequency f2. For example, both transducers Tr1 and Tr2 may be located on the front right side of the vehicle. This is the same as Figure 6 except that the two transducers are located in the same location. Note that "in the same location" means that the two transducers are located, for example, within a radius of 5 cm.

[0052] In (a) of Figure 8, of two transducers located adjacent to each other, transducer Tr1 transmits an ultrasonic signal of frequency f1, transducer Tr2 transmits an ultrasonic signal of frequency f2 simultaneously with transducer Tr1, and both transducers Tr1 and Tr2 receive the ultrasonic signal of frequency f1 and the ultrasonic signal of frequency f2.

[0053] In (b) of Figure 8, after the transmission and reception in (a) of Figure 8, transducer Tr1 transmits an ultrasonic signal of frequency f2, transducer Tr2 transmits an ultrasonic signal of frequency f1 simultaneously with transducer Tr1, and both transducers Tr1 and Tr2 receive the ultrasonic signals of frequency f1 and frequency f2.

[0054] The transducer Tr1 may be disposed on the front right side of the vehicle, and the transducer Tr2 may be disposed in the center of the front right side of the vehicle. A multi-resonance point transducer may be used as a transducer that transmits and / or receives ultrasonic signals of multiple frequencies (see, for example, Patent Document 3).

[0055] The transmitted wave shown in FIG. 8(a) and the transmitted wave shown in FIG. 8(b) are alternately repeated.

[0056] For example, the transducers Tr1 and Tr2 may be the transducers 233 having the configuration shown in FIG. 2 and may be provided in the sonar devices 111 and 112, respectively.

[0057] The ECU 120 controls the transmission control circuit 210 of the sonar device 111, causing the sonar device 111 to transmit an ultrasonic signal of frequency f1 and receive ultrasonic signals of frequency f1 and frequency f2. The ECU 120 also controls the transmission control circuit 210 of the sonar device 112, causing the sonar device 112 to transmit an ultrasonic signal of frequency f2 and receive ultrasonic signals of frequency f1 and frequency f2. The transmission of waves by the sonar device 111 and the sonar device 112 is simultaneous.

[0058] The ECU 120 detects objects based on the received signal of frequency f1 received by the sonar device 111 and the received signal of frequency f2 received by the sonar device 112. Each sonar can receive a strong received signal of at least one of the frequencies, and therefore can detect objects based on the strong received signal.

[0059] Furthermore, transducer Tr1 and transducer Tr2 may be transducer 233-1 and transducer 233-2, respectively, having the configurations shown in Figure 3, with transducer Tr1 being positioned on the front right side of the vehicle and transducer Tr2 being positioned in the center of the front right side of the vehicle.

[0060] The transmission control circuit 310 may cause the sensor #1 having the transducer Tr1 to transmit an ultrasonic signal of frequency f1, and the sensor #2 having the transducer Tr2 to transmit an ultrasonic signal of frequency f2. The transmission of the ultrasonic signal from the transducer Tr1 and the transmission of the ultrasonic signal from the transducer Tr2 are simultaneous.

[0061] The transmission control circuit 310 detects objects based on the received signals of frequencies f1 and f2 received by each sonar device. Each transducer can receive a strong received signal of at least one of the frequencies, so the transmission control circuit 310 can detect objects based on the strong received signal.

[0062] In (a) of Figure 9, of the two transducers located in the same location, transducer Tr1 simultaneously transmits an ultrasonic signal of frequency f1 and transducer Tr2 simultaneously transmits an ultrasonic signal of frequency f2, and both transducers Tr1 and Tr2 receive the ultrasonic signals of frequency f1 and frequency f2. In (b) of Figure 9, transducer Tr2 simultaneously transmits an ultrasonic signal of frequency f1 and transducer Tr1 simultaneously transmits an ultrasonic signal of frequency f2, and both transducers Tr1 and Tr2 receive the ultrasonic signals of frequency f1 and frequency f2. For example, transducers Tr1 and Tr2 may both be located on the front right side of the vehicle. This is the same as Figure 8 except that the two transducers are located in the same location.

[0063] In FIG. 10(a), one transducer transmits an ultrasonic signal at frequency f1, and then in FIG. 10(b), it transmits an ultrasonic signal at frequency f2.

[0064] Even with a single transducer, if the object is not moving, a strong received signal of at least one of the frequencies can be obtained, making it possible to detect the object based on the strong received signal.

[0065] The wave transmission according to each embodiment may be performed when the object is determined to have a complex shape. In this case, the detection circuit 220 determines whether the object has a complex shape based on the wave reception signal.

[0066] For example, the waveform of a received signal reflected by an object with a simple shape, such as a wall or a pillar, will be almost the same as the waveform of the transmitted signal, but the waveform of a received signal reflected by an object with a complex shape, such as a human, will be a variety of waveforms.

[0067] When the detection circuit 220 determines that the object has a complex shape, the transmission control circuits 210 and 310 cause the transducer to transmit transmission signals at multiple frequencies. The method for determining whether the object has a complex shape will be described later.

[0068] When processing received signals of multiple frequencies, power consumption increases compared to processing received signals of a single frequency. However, if it is determined that the object has a complex shape, power consumption can be reduced by transmitting signals at multiple frequencies.

[0069] A method for determining whether an object has a complex shape will be described below. When an object has a complex shape, the interference situation of the received signal changes significantly due to the movement of the object and / or vehicle, resulting in large fluctuations in the reception strength of the received signal. Therefore, by detecting fluctuations in the reception strength of the received signal, it is possible to determine whether an object has a complex shape.

[0070] 11, the detection circuit 220 determines that an object has a complex shape when the difference between the reception strength of the received wave signal and the reception strength of a wave signal received previously (for example, in the previous frame) is equal to or greater than a threshold. While Fig. 11 shows an example in which the reception strength of frame n+1 is lower than that of frame n, the reception strength of frame n+1 may also be higher than that of frame n.

[0071] In FIG. 12, the detection circuit 220 may determine that an object has a complex shape when the reception strength of the received wave signal is less than a threshold. When the reception strength of the received wave signal fluctuates greatly, the detection circuit 220 may also receive a received wave signal with a low reception strength. Furthermore, when the shape is complex, the reflection of the ultrasonic signal may be complex, resulting in a weak reception strength. Therefore, by detecting the reception strength, it is possible to determine whether or not the object has a complex shape. The threshold may be a reception strength according to the TOF (Time of Flight).

[0072] The received signal used for the determination is the first received signal, but the second or subsequent received signals may also be used. If the received signals are determined to have been reflected by the same object (for example, the difference in TOF between the received signals is equal to or less than a predetermined value), they can be used for the determination.

[0073] If the object has a complex shape, when signals reflected from various parts of the object (for example, the torso and legs) are received, the number of peaks (maximum values) in the reception strength of the received signals will be large, as shown in Figure 13.

[0074] Therefore, the detection circuit 220 may determine that the object has a complex shape when the number of peaks in the reception strength of the received wave signal is equal to or greater than a threshold value.

[0075] Furthermore, the detection circuit 220 may determine that an object has a complex shape when the number of parts of the received signal that exceed the threshold is equal to or greater than the threshold. By using the parts that exceed the threshold as a substitute for peaks, the number of peaks can be approximated by the number of parts that exceed the threshold.

[0076] In this case, the determination of whether or not an object has a complex shape is made based on the number of peaks or portions exceeding the threshold of the first received signal, but may also be made based on the number of peaks or portions exceeding the threshold of the second or subsequent received signals.

[0077] Alternatively, it may be possible to determine whether an object has a complex shape using the following method.

[0078] When an object has a complex shape, signals reflected from various parts of the object (for example, the torso and legs) overlap and are received, resulting in a wide received signal, as shown in FIG.

[0079] Therefore, the detection circuit 220 may determine that the object has a complex shape when the time during which the reception strength of the received wave signal is equal to or greater than the first threshold is equal to or greater than the second threshold.

[0080] In this case, the determination of whether or not the object has a complex shape is made based on the first received wave signal, but may also be made based on the second or subsequent received wave signals.

[0081] Furthermore, the threshold values ​​in each of the above-described methods may be set statically or may be set dynamically depending on past reception conditions.

[0082] Next, the procedure of the process executed by transmission control circuit 310 will be described with reference to Fig. 15. The process of Fig. 15 is executed by transmission control circuit 310, but may also be executed by ECU 120.

[0083] First, the transmission control circuit 310 causes the transducer to transmit a transmission signal at one frequency (step S1501).

[0084] Then, the transmission control circuit 310 determines whether or not an object with a complex shape has been detected (step S1502).

[0085] If it is determined that an object with a complex shape has been detected (step S1502, Yes), the transmission control circuit 310 causes the transducer to transmit ultrasonic signals at a plurality of frequencies (step S1503).

[0086] The method of transmitting waves at multiple frequencies can be any of the methods described with reference to Figures 6 to 10. After transmitting ultrasonic signals at multiple frequencies, the process returns to step S1502, and it is determined whether an object with a complex shape has been detected.

[0087] If the transmission control circuit 310 determines that the detection circuit 220 has not detected an object with a complex shape (step S1502, No), the process returns to step S1501, and causes the transducer to transmit a transmission signal at one frequency.

[0088] In this way, when it is determined that the object is a complex-shaped object such as a human, power consumption can be reduced by transmitting wave signals at multiple frequencies.

[0089] Although the embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims. It is understood that such modifications or alterations also fall within the technical scope of the present disclosure. Furthermore, the components in the embodiments may be combined in any manner without departing from the spirit of the present disclosure.

[0090] In the above description, the expression "... part" used for each component may be replaced with other expressions such as "... assembly," "... circuit," "... device," "... unit," or "... module." Also, the sonar device may be configured to be executed by a processor using a program stored in memory built into the ECU.

[0091] (1) A sonar device in one embodiment of the present disclosure includes a transmitting circuit that transmits transmitted signals of multiple frequencies, a receiving circuit that receives received signals corresponding to the transmitted signals of the multiple frequencies, and a detecting circuit that detects an object based on the received signals, wherein the multiple frequencies are determined so that the power of a composite signal of received signals having at least one frequency among the multiple frequencies is greater than the power of each received signal that constitutes the composite signal.

[0092] (2) In one embodiment of the present disclosure, the sonar device is the sonar device of (1), wherein the transmission signal is a chirp signal.

[0093] (3) In one embodiment of the present disclosure, the sonar device is the sonar device of (1), wherein the plurality of frequencies includes a first frequency and a second frequency that is twice the first frequency.

[0094] (4) In one embodiment of the sonar device of the present disclosure, in the sonar device of (1), the transmitting circuit transmits the transmission signal at the multiple frequencies corresponding to the multiple resonance points via a transducer having the multiple resonance points.

[0095] (5) In one embodiment of the present disclosure, the sonar device is the sonar device of (1), further comprising a transmission control circuit that controls a transmission method for the transmission signals of the plurality of frequencies based on the received signals.

[0096] (6) In one embodiment of the sonar device of the present disclosure, in the sonar device of (5), the transmission control circuit controls the multiple transducers to simultaneously transmit each transmission signal that constitutes the transmission signals of the multiple frequencies.

[0097] (7) In one embodiment of the sonar device of the present disclosure, in the sonar device of (5), the transmission control circuit controls one transducer to transmit each transmission signal constituting the transmission signals of the multiple frequencies at different timings.

[0098] (8) In one embodiment of the present disclosure, the sonar device is the sonar device of (5), further comprising a detection circuit that determines whether the object has a complex shape based on the received signal, and the transmission control circuit transmits transmission signals of the multiple frequencies when the object is determined to be an object with a complex shape, and transmits a transmission signal of a single frequency when the object is not determined to be an object with a complex shape.

[0099] (9) In one embodiment of the sonar device of the present disclosure, in the sonar device of (8), the detection circuit determines whether the object has a complex shape based on the reception strength of the received wave signal.

[0100] (10) In one embodiment of the sonar device of the present disclosure, in the sonar device of (8), the detection circuit determines whether the object has a complex shape based on the number of peaks in the received signal or the number of portions where the received signal exceeds a threshold.

[0101] (11) In one embodiment of the sonar device of the present disclosure, in the sonar device of (8), the detection circuit determines whether the object has a complex shape based on the reception time of the received signal.

[0102] (12) In one embodiment of the present disclosure, a vehicle is equipped with the sonar device of (1).

[0103] (13) An object detection method in one embodiment of the present disclosure includes transmitting transmission signals of multiple frequencies, receiving reception signals corresponding to the transmission signals of the multiple frequencies, and detecting an object based on the reception signals, wherein the multiple frequencies are determined so that the power of a composite signal of reception signals having at least one frequency among the multiple frequencies is greater than the power of each reception signal that constitutes the composite signal.

[0104] (14) An object detection method according to one embodiment of the present disclosure is the object detection method according to (13), wherein the transmission signal is a chirp signal.

[0105] (15) An object detection method according to one embodiment of the present disclosure is the object detection method according to (13), wherein the plurality of frequencies includes a first frequency and a second frequency that is twice the first frequency.

[0106] (16) An object detection method in one embodiment of the present disclosure is the object detection method of (13), wherein the transmission signal is transmitted via a transducer having multiple resonance points at the multiple frequencies corresponding to the multiple resonance points.

[0107] (17) An object detection method according to one embodiment of the present disclosure is the object detection method of (13), wherein the method of transmitting the transmission signals of the multiple frequencies is controlled based on the received signals.

[0108] (18) An object detection method in one embodiment of the present disclosure is the object detection method of (17), wherein the transmission signal is transmitted by a plurality of transducers, and the plurality of transducers are controlled to simultaneously transmit each transmission signal constituting the transmission signal of the plurality of frequencies.

[0109] (19) An object detection method in one embodiment of the present disclosure is the object detection method of (17), wherein the transmission signal is transmitted by one transducer, and the one transducer is controlled to transmit each transmission signal constituting the transmission signals of the multiple frequencies at different timings.

[0110] (20) An object detection method in one embodiment of the present disclosure is the object detection method of (17), further comprising: determining whether the object has a complex shape based on the received wave signal; if the object is determined to be an object with a complex shape, transmitting wave signals of the multiple frequencies; and if the object is not determined to be an object with a complex shape, transmitting a wave signal of a single frequency. [Explanation of symbols]

[0111] 100: Vehicle 111~118, 200, 300: Sonar equipment 120:ECU 210, 310: Transmission control circuit 220: Detection circuit 230: Sensor 231: Transmitting circuit 232: Receiving circuit 233: Transducer

Claims

1. a transmitting circuit for transmitting transmission signals of a plurality of frequencies; a receiving circuit for receiving received signals corresponding to the transmitted signals of the plurality of frequencies; a detection circuit that detects an object based on the received wave signal; Equipped with the plurality of frequencies are determined so that the power of a composite signal of received signals having at least one frequency among the plurality of frequencies is greater than the power of each received signal constituting the composite signal; Sonar equipment.

2. The transmission signal is a chirp signal.

10. The sonar device of claim 1.

3. the plurality of frequencies includes a first frequency and a second frequency that is twice the first frequency; 10. The sonar device of claim 1.

4. the transmission circuit transmits the transmission signal at the plurality of frequencies corresponding to the plurality of resonance points via a transducer having the plurality of resonance points; 10. The sonar device of claim 1.

5. Further, a transmission control circuit is provided that controls a transmission method of the transmission signals of the plurality of frequencies based on the received signal.

10. The sonar device of claim 1.

6. the transmission control circuit controls the plurality of transducers to simultaneously transmit the respective transmission signals constituting the transmission signals of the plurality of frequencies; 6. The sonar device of claim 5.

7. the transmission control circuit controls one transducer to transmit each of the transmission signals constituting the transmission signals of the plurality of frequencies at different timings; 6. The sonar device of claim 5.

8. a detection circuit for determining whether the object has a complex shape based on the received wave signal; the transmission control circuit transmits the transmission signals of the plurality of frequencies when the object is determined to be an object with a complex shape, and transmits the transmission signal of a single frequency when the object is not determined to be an object with a complex shape.

6. The sonar device of claim 5.

9. the detection circuit determines whether the object has a complex shape based on the reception intensity of the received wave signal.

9. The sonar device of claim 8.

10. The detection circuit determines whether the object has a complex shape based on the number of peaks in the received signal or the number of portions in which the received signal exceeds a threshold.

9. The sonar device of claim 8.

11. the detection circuit determines whether the object has a complex shape based on the reception time of the received wave signal.

9. The sonar device of claim 8.

12. A vehicle equipped with the sonar device according to claim 1.

13. Transmitting transmission signals of multiple frequencies, receiving received signals corresponding to the transmitted signals of the plurality of frequencies; Detecting an object based on the received wave signal; 1. A method for detecting an object, comprising: the plurality of frequencies are determined so that the power of a composite signal of received signals having at least one frequency among the plurality of frequencies is greater than the power of each received signal constituting the composite signal; Object detection methods.

14. The transmission signal is a chirp signal. The object detection method according to claim 13.

15. the plurality of frequencies includes a first frequency and a second frequency that is twice the first frequency; The object detection method according to claim 13.

16. The transmission signal is transmitted via a transducer having a plurality of resonance points at the plurality of frequencies corresponding to the plurality of resonance points. The object detection method according to claim 13.

17. The method of transmitting the transmission signals of the plurality of frequencies is controlled based on the reception signal. The object detection method according to claim 13.

18. The transmission signals are transmitted by a plurality of transducers; The plurality of transducers are controlled to simultaneously transmit the respective transmission signals constituting the transmission signals of the plurality of frequencies. The object detection method according to claim 17.

19. The transmission signal is transmitted by one transducer; The one transducer is controlled to transmit each transmission signal constituting the transmission signals of the plurality of frequencies at different timings. The object detection method according to claim 17.

20. Further, it is determined whether the object has a complex shape based on the received wave signal; When the object is determined to be an object having a complex shape, the wave transmission signals of the plurality of frequencies are transmitted, and when the object is not determined to be an object having a complex shape, the wave transmission signal of a single frequency is transmitted. The object detection method according to claim 17.

Images