Obstacle Detection Device, Obstacle Detection Method, and Program

Abstract

To provide an obstacle detection device capable of reducing the possibility of false detection of an obstacle due to interference waves.SOLUTION: An obstacle detection device according to the present disclosure includes a transmission circuit, a reception circuit, an object detection circuit, an interference detection circuit, and a determination circuit. The transmission circuit transmits a frequency-modulated transmission wave signal. The reception circuit receives a signal from the outside. The object detection circuit detects an object present in a transmission wave direction of the transmission wave signal based on a reflected wave of the transmission wave signal received by the reception circuit. The interference detection circuit detects, as interference, another transmission wave signal transmitted from another transmission circuit different from the transmission circuit, based on a signal received by the reception circuit. The determination circuit determines a frequency modulation pattern to be applied to the transmission wave signal and the transmission timing of the transmission wave signal, based on detection results of the object detection circuit and the interference detection circuit.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to an obstacle detection device, an obstacle detection method, and a program.

Background Art

[0002] Conventionally, a technique for detecting an object such as a preceding vehicle, an obstacle, or a pedestrian using a ranging sensor such as a transceiver mounted on a vehicle is known. Further, based on the object detection result by the ranging sensor, various controls for improving the driving safety of the vehicle, for example, techniques for operating an automatic brake and notifying a driver are known.

[0003] As the ranging sensor, a sonar that transmits ultrasonic waves and detects an object by receiving a reflected wave reflected by an object around the vehicle is known.

[0004] By the way, when there is a vehicle equipped with another sonar around a vehicle equipped with a sonar, if both vehicles unconditionally transmit ultrasonic waves of the same frequency, the sonar may cause misdetection of an object due to the influence of the transmission of ultrasonic waves from the other vehicle.

[0005] Conventionally, when an interference wave is detected, misdetection has been prevented by changing at least one or more of the initial time, phase, and period of the modulation signal.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when vehicles equipped with a control device that performs the same sonar control face each other while the vehicle is reversing for purposes such as parking, modulation is similarly performed, ultrasonic interference occurs in each vehicle, and it is difficult to accurately measure the distance value for parking, and false detection may occur.

[0008] The present disclosure provides an obstacle detection device capable of reducing the possibility of false detection of an obstacle due to an interference wave.

Means for Solving the Problems

[0009] The obstacle detection device according to the present disclosure includes a transmission circuit, a reception circuit, an object detection circuit, an interference detection circuit, and a determination circuit. The transmission circuit transmits a carrier signal subjected to frequency modulation. The reception circuit receives a signal from the outside. The object detection circuit detects an object existing in the transmission direction of the carrier signal based on the reflected wave of the carrier signal received by the reception circuit. The interference detection circuit detects, as interference, another carrier signal transmitted from another transmission circuit different from the transmission circuit based on the signal received by the reception circuit. The determination circuit determines a frequency modulation pattern applied to the carrier signal and a transmission timing of the carrier signal based on the detection results of the object detection circuit and the interference detection circuit.

Effects of the Invention

[0010] According to the obstacle detection device according to the present disclosure, the possibility of false detection of an obstacle due to an interference wave can be reduced.

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a vehicle equipped with an in-vehicle system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a sonar according to an embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the waveform of ultrasonic waves transmitted by a sonar according to an embodiment in a first pattern. [Figure 4]FIG. 4 is a diagram showing an example of the waveform of ultrasonic waves received by the sonar according to the embodiment in the first pattern. [Figure 5] FIG. 5 is a diagram showing an example of the waveform of ultrasonic waves transmitted by the sonar according to the embodiment in the second pattern. [Figure 6] FIG. 6 is a diagram showing an example of the waveform of ultrasonic waves received by the sonar according to the embodiment in the second pattern. [Figure 7] FIG. 7 is a diagram showing an example of the hardware configuration of the sensor control device according to the embodiment. [Figure 8] FIG. 8 is a block diagram showing an example of the functions provided by the sensor control device according to the embodiment. [Figure 9] FIG. 9 is a diagram showing an example of the positional relationship between the vehicle according to the embodiment and another vehicle. [Figure 10] FIG. 10 is a diagram for explaining an example of the flow of processing of each part of the vehicle according to the embodiment. [Figure 11] FIG. 11 is a diagram for explaining an example of the flow of processing of each part of the vehicle according to the embodiment. [Figure 12] FIG. 12 is an explanatory diagram showing an example of the received signal according to the embodiment. [Figure 13] FIG. 13 is a diagram for explaining an example of the flow of processing of each part of the vehicle according to the embodiment. [Figure 14] FIG. 14 is an explanatory diagram showing an example of the received signal according to the embodiment. [Figure 15] FIG. 15 is a diagram showing an example of the interference relationship between vehicle 1A and vehicle 1B according to the embodiment. [Figure 16] FIG. 16 is a diagram showing an example of the interference relationship between vehicle 1A and vehicle 1B according to the embodiment. [Figure 17] FIG. 17 is a diagram showing an example of the data table according to the embodiment. [Figure 18] FIG. 18 is a diagram showing an example of the data table according to the embodiment. [Figure 19] FIG. 19 is a diagram schematically showing an example of the interference pattern of the data table according to the embodiment. [Figure 20]FIG. 20 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 21] FIG. 21 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 22] FIG. 22 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 23] FIG. 23 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 24] FIG. 24 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 25] FIG. 25 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 26] FIG. 26 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 27] FIG. 27 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 28] FIG. 28 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 29] FIG. 29 is a diagram schematically showing an example of an interference pattern of a data table according to an embodiment. [Figure 30] FIG. 30 is a diagram for explaining an example of a processing flow of each part of a vehicle according to an embodiment. [Figure 31] FIG. 31 is a flowchart showing an example of processing executed by a sensor control device according to an embodiment. [Figure 32] FIG. 32 is a diagram for explaining an example of a processing flow executed by a sensor control device according to Modification 2. [Figure 33] FIG. 33 is a diagram showing an example of a data table according to Modification 3. [Figure 34] FIG. 34 is a diagram showing an example of a data table according to Modification 3. [Figure 35]FIG. 35 is a diagram showing an example of a data table according to Modification 3. Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of an obstacle detection device according to the present disclosure will be described with reference to the drawings.

[0013] As shown in FIG. 1, the vehicle 1 includes a steering control device 30, a speed control device 40, a vehicle control device 50, an HMI (Human Machine Interface) device 60, a sensor control device 70, and an alarm device 80.

[0014] In the present embodiment, the in-vehicle system 100 includes the steering control device 30, the speed control device 40, the vehicle control device 50, the HMI device 60, the sensor control device 70, and the alarm device 80. Note that other devices may be further mounted on the vehicle 1. Also, in FIG. 1, the steering control device 30, the speed control device 40, the vehicle control device 50, the HMI device 60, the sensor control device 70, and the alarm device 80 are shown as separate devices, but some or all of these devices may be integrated.

[0015] The vehicle 1 also includes a first front center sonar 21a, a second front center sonar 21b, a first front corner sonar 21c, a second front corner sonar 21d, a first rear center sonar 22a, a second rear center sonar 22b, a first rear corner sonar 22c, and a second rear corner sonar 22d.

[0016] In the following description, the first front center sonar 21a, the second front center sonar 21b, the first front corner sonar 21c, the second front corner sonar 21d, the first rear center sonar 22a, the second rear center sonar 22b, the first rear corner sonar 22c, and the second rear corner sonar 22d are also simply referred to as sonars 21a, 21b, 21c, 21d, 22a, 22b, 22c, and 22d.

[0017] Sonars 21a, 21b, 21c, 21d, 22a, 22b, 22c, and 22d are examples of a transmission unit and a reception unit. Among sonars 21a, 21b, 21c, 21d, 22a, 22b, 22c, and 22d, sonars 21a, 21b, 21c, and 21d are provided at the front end of vehicle 1. Also, sonars 22a, 22b, 22c, and 22d are provided at the rear end of vehicle 1.

[0018] Hereinafter, when not distinguishing between individual sonars 21a, 21b, 21c, 21d, 22a, 22b, 22c, and 22d and sonars 22a, 22b, 22c, and 22d, they are also referred to as sonar 21 and sonar 22. Also, when collectively referring to sonars 21a, 21b, 21c, and 21d, they are also referred to as front sonar 21. Also, when collectively referring to sonars 22a, 22b, 22c, and 22d, they are also referred to as rear sonar 22.

[0019] Sonars 21 and 22 are arranged on vehicle 1 at positions advantageous for detecting or ranging surrounding objects. For example, a plurality of sonars 21 and 22 are arranged at intervals on the bumpers at the front end and the rear end of vehicle 1 to detect objects in front of and behind vehicle 1.

[0020] Sonars 21 and 22 are provided in vehicle 1. Sonars 21 and 22 transmit ultrasonic waves subjected to frequency modulation. Ultrasonic waves are an example of a transmission signal. Also, sonars 21 and 22 receive signals from the outside. Here, the signals include reflected waves of ultrasonic waves. Sonars 21 and 22 detect objects around vehicle 1 and obtain distance information to the detected objects by measuring the time from transmitting ultrasonic waves until receiving the reflected waves reflected by the objects around vehicle 1.

[0021] In addition, when referring to an "object" or an "obstacle" in this embodiment, it shall include pedestrians and other vehicles. Further, things that do not hinder the running of Vehicle 1, such as unevenness on the road surface, etc., are not included in the obstacles.

[0022] More specifically, a sonar 21a and a sonar 21b are provided at the center of the front end portion of Vehicle 1. Also, at the front end portion of Vehicle 1, near the corner portions outside the sonars 21a and 21b, sonars 21c and 21d are provided.

[0023] Also, a sonar 22a and a sonar 22b are provided at the center of the rear end portion of Vehicle 1. Also, at the rear end portion of Vehicle 1, near the corner portions outside the sonars 22a and 22b, sonars 22c and 22d are provided.

[0024] In FIG. 1, the range within which the sonar 21a can detect an object is defined as a detection range 210a, the range within which the sonar 21b can detect an object is defined as a detection range 210b, the range within which the sonar 21c can detect an object is defined as a detection range 210c, and the range within which the sonar 21d can detect an object is defined as a detection range 210d. When not distinguishing the individual detection ranges 210a to 210d, it is simply also referred to as a detection range 210.

[0025] Also, the range within which the sonar 22a can detect an object is defined as a detection range 220c, the range within which the sonar 22b can detect an object is defined as a detection range 220b, the range within which the sonar 22c can detect an object is defined as a detection range 220c, and the range within which the sonar 22d can detect an object is defined as a detection range 220d. When not distinguishing the individual detection ranges 220a to 210d, it is simply also referred to as a detection range 220.

[0026] Note that in FIG. 1, the detection ranges 210 and the detection range 220 are shown separately, but actually, the adjacent detection ranges 210 and the adjacent detection ranges 220 may overlap.

[0027] When not distinguishing between sonar 21a, sonar 21b, sonar 22a, and sonar 22b, they are also collectively referred to as center sonar 21a, 21b, 22a, and 22b. When not distinguishing between sonar 21c, sonar 21d, sonar 22c, and sonar 22d, they are also collectively referred to as corner sonar 21c, 21d, 22c, and 22d. Note that the vehicle 1 may omit the corner sonar 21c, 21d, 22c, and 22d.

[0028] Hereinafter, in this embodiment, mainly taking the case where the traveling direction of the vehicle 1 is backward as an example, specific descriptions will be given. However, for example, when the traveling direction of the vehicle 1 is forward, the functions exemplified using the rear sonar 22 may be applied to the front sonar 21.

[0029] When the vehicle 1 travels straight backward, obstacles located in the traveling direction of the vehicle 1 are detected by the inner sonar 22a and sonar 22b. When the vehicle 1 turns left or right backward, objects located at the left or right turn destination are detected by sonar 22c or sonar 22d.

[0030] Furthermore, when an obstacle enters from the right side of the vehicle 1 to the right rear of the vehicle 1, sonar 22c or the second rear center sonar 22a detects it first. When an obstacle enters from the left side of the vehicle 1 to the left rear of the vehicle 1, sonar 22d or sonar 22b detects it first.

[0031] Also, the installation locations and numbers of the sonar 21 and sonar 22 are not limited to the example shown in FIG. 1. Note that in addition to the sonar 21 and sonar 22, the vehicle 1 may be equipped with imaging devices such as cameras, radars, antennas capable of receiving GPS (Global Positioning System) signals, and GPS devices (not shown) for specifying GPS coordinates representing the position of the vehicle 1 based on the received GPS signals as sensors.

[0032] Here, the sonar 21 and the sonar 22 will be described in detail with reference to Fig. 2. The sonar 21 and the sonar 22 are also referred to as sonar modules. The sonar module includes a controller 23, a drive circuit 241, a receiving circuit 242, and a piezoelectric element 25.

[0033] First, the drive circuit 241, the receiving circuit 242, and the piezoelectric element 25 will be described. The sonar module transmits ultrasonic waves by applying a voltage to the piezoelectric element 25. The controller 23 controls the drive circuit 241 to apply a voltage of, for example, 50 KHz to the piezoelectric element 25, causing the piezoelectric element 25 to transmit ultrasonic waves of the same frequency. The transmitted ultrasonic waves are pulsed. When the pulsed ultrasonic waves hit the road surface or an obstacle, they are reflected, and a portion of them returns to the sonar 21 and the sonar 22.

[0034] Furthermore, the piezoelectric element 25 converts the sound pressure of the returned reflected wave into a voltage. The receiving circuit 242 amplifies and rectifies the voltage converted from the sound pressure by the piezoelectric element 25, and converts it into a sound wave reception intensity. The waveform that shows the time change in the converted sound wave reception intensity is called an echo waveform.

[0035] The received signal and the amplified received signal are AC, and the sound wave received intensity is the rectified amplified received signal, so there is a difference between AC and DC, but since both are obtained by processing the received signal, they are sometimes collectively referred to as the received signal without distinguishing between AC and DC. The receiving circuit 242 is equipped with an amplifier circuit (amplifier) not shown that amplifies the voltage converted from the sound pressure by the piezoelectric element 25.

[0036] Furthermore, under the control of the sensor control device 70, the sonar module transmits ultrasonic waves using frequency modulation A or frequency modulation B which is different from frequency modulation A. Frequency modulation A and frequency modulation B are examples of frequency modulation patterns.

[0037] Here, frequency modulation A and frequency modulation B will be described with reference to FIGS.

[0038] As shown in Figure 3, when the sonar module uses frequency modulation A as the frequency modulation pattern, it changes the frequency of the ultrasound from a low frequency to a high frequency and transmits the ultrasound. Frequency modulation A is an example of the first or second pattern. Furthermore, when the sonar module receives the reflected waves of the ultrasound transmitted using frequency modulation A, the ultrasound is attenuated, and as shown in Figure 4, the received ultrasound has a reduced amplitude compared to when it was transmitted.

[0039] As shown in Figure 5, when the sonar module uses frequency modulation B as the frequency modulation pattern, it changes the frequency of the ultrasound from a high frequency to a low frequency and transmits the ultrasound. Frequency modulation B is an example of the first or second pattern. Furthermore, when the sonar module receives the reflected waves of the ultrasound transmitted using frequency modulation A, the ultrasound is attenuated, and as shown in Figure 6, the received ultrasound has a reduced amplitude compared to when it was transmitted.

[0040] In this embodiment, frequency modulation A and frequency modulation B are used as the frequency modulation patterns, but the frequency modulation patterns are not limited to this. For example, either frequency modulation A or frequency modulation B may be a constant frequency. Furthermore, frequency modulation may be performed using a pattern different from frequency modulation A and frequency modulation B.

[0041] Returning to FIG. 2 , the controller 23 will be described. The controller 23 performs overall control of the sonar module. The controller 23 includes a communication circuit 231, a timer 232, a waveform memory 233, a threshold memory 234, and a determination circuit 235. The controller 23 is connected to the sensor control device 70 via a transmission path 27. The controller 23 may also be connected to the vehicle control device 50, etc. via the transmission path 27.

[0042] The communication circuit 231 controls communication between the controller 23 and other devices. For example, the communication circuit 231 transmits and receives data to and from the sensor control device 70 via the transmission line 27. The communication circuit 231 receives a sonar control signal from the sensor control device 70. Further, the communication circuit 231 transmits detection information indicating whether a reflected wave having an intensity exceeding a threshold value is received, distance information indicating the distance from the vehicle 1 to the target, and the like to the sensor control device 70.

[0043] The timer 232 measures time. For example, the sonar control signal includes a delay time when transmitting ultrasonic waves. The timer 232 starts measuring time from the point in time when the communication circuit 231 receives the sonar control signal, and transmits a drive signal for driving the drive circuit 241 after the elapse of the delay time. Thereby, the sonar module can transmit ultrasonic waves at the transmission timing determined by the sonar control signal.

[0044] The waveform memory 233 stores the echo waveform. The threshold memory 234 stores a short-distance interference detection threshold 810, an obstacle detection threshold 811, and a long-distance interference detection threshold 812 (see FIGS. 12 and 14 in both cases). The short-distance interference detection threshold 810 is an example of the second threshold value. Further, the obstacle detection threshold 811 is an example of the first threshold value. Further, the long-distance interference detection threshold 812 is an example of the third threshold value. The short-distance interference detection threshold 810, the obstacle detection threshold 811, and the long-distance interference detection threshold 812 will be described later.

[0045] The determination circuit 235 compares the amplified received signal with the short-distance interference detection threshold 810, the obstacle detection threshold 811, and the long-distance interference detection threshold 812 stored in the threshold memory 234. More precisely, the amplified received signal is rectified to obtain the sound wave reception intensity, and this sound wave reception intensity is compared with each detection threshold value. In the following description, for the sake of avoiding complexity, there may be cases where it is simply expressed that the received signal is compared with the threshold value.

[0046] The determination circuit 235 calculates distance information indicating the distance from the vehicle 1 to the target (the position where short-distance interference occurs, the position of the obstacle, and the position where long-distance interference occurs) based on the comparison result between the received signal and each detection threshold value. The determination circuit 235 sends the calculated distance information to the communication circuit 231. The communication circuit 231 transmits the distance information sent from the determination circuit 235 to the sensor control device 70 via the transmission line 27.

[0047] Returning to FIG. 1 and continuing the explanation. The steering control device 30 controls the steering angle of the vehicle 1. The steering control device 30 is also referred to as a steering angle control device. The steering control device 30 is arranged, for example, at a position advantageous for the steering assist of the power steering of the vehicle 1.

[0048] The speed control device 40 controls the acceleration and braking of the vehicle 1. The speed control device 40 is arranged, for example, at a position advantageous for the control of the engine or motor and the brake.

[0049] The vehicle control device 50 is a device that controls various behaviors of the vehicle 1 and is arranged, for example, in the vicinity of the steering control device 30 and the speed control device 40.

[0050] The HMI device 60 may include a display (not shown) capable of displaying information and a touch panel or switch etc. capable of receiving operations by the user. Note that the display and the touch panel may be configured as an integrated device. The display is also referred to as a display unit. The touch panel and the switch are also referred to as an operation unit. Further, the display unit and the operation unit included in the HMI device 60 are arranged around the driver's seat.

[0051] The warning device 80 warns the driver of other vehicles and obstacles detected by the vehicle control device 50 and the sensor control device 70. Note that the warning device 80 may be a configuration included in the HMI device 60.

[0052] The sensor control device 70 controls the sonar module. The sensor control device 70 and the sonar module are examples of an obstacle detection device in this embodiment. The obstacle detection device may include the entire in-vehicle system 100, or any of the steering control device 30, speed control device 40, vehicle control device 50, HMI device 60, and warning device 80 included in the in-vehicle system 100.

[0053] The steering control device 30, the speed control device 40, the vehicle control device 50, the HMI device 60, and the sensor control device 70 are connected by wire, for example, via a local area network such as a CAN (Controller Area Network). The sonar 21, the sonar 22, and the imaging device 16 may be connected to the local area network, or may be connected to the sensor control device 70 or the vehicle control device 50 by dedicated wiring.

[0054] Next, we will explain the hardware configuration of the sensor control device 70. As shown in Fig. 7, the sensor control device 70 has a hardware configuration that uses a normal computer, in which a CPU (Central Processing Unit) 11A, a ROM (Read Only Memory) 11B, a RAM (Random Access Memory) 11C, an I / F (Interface) 11D, a flash memory 11E, etc. are interconnected via a bus 11F.

[0055] The CPU 11A is a computing device that controls the entire sensor control device 70. The CPU 11A is an example of a processor, and another processor or processing circuit may be provided instead of the CPU 11A. The ROM 11B stores programs and the like that realize various processes by the CPU 11A. The RAM 11C is, for example, a main storage device of the sensor control device 70, and stores data used for various processes by the CPU 11A.

[0056] I / F11D is an interface for transmitting and receiving data. Also, I / F11D may transmit and receive information with other devices mounted on vehicle 1 via CAN or the like within vehicle 1. Further, flash memory 11E is an example of a writable non-volatile storage medium. ROM11B, RAM11C, and flash memory 11E are also referred to as a storage unit. Note that the sensor control device 70 may include another storage device such as an HDD (Hard Disk Drive) instead of or in addition to flash memory 11E.

[0057] Also, the hardware configurations of the steering control device 30, the speed control device 40, the vehicle control device 50, and the HMI device 60 are also assumed to include a processing circuit such as a CPU, a ROM, a RAM, an I / F, and a flash memory or the like.

[0058] As shown in FIG. 8, the sensor control device 70 includes a first detection unit 701, a sonar control unit 702, an acquisition unit 703, and a second detection unit 704. Note that the functions included in the sensor control device 70 are not limited to these.

[0059] The first detection unit 701 detects an action that serves as a trigger for operating the sonar module. For example, the first detection unit 701 detects the start of vehicle reverse. In this case, the first detection unit 701 detects an electrical signal (hereinafter also referred to as +B) output from the battery when the driver of vehicle 1 puts the gear into reverse as a signal that serves as a trigger for operating the sonar 22.

[0060] The sonar control unit 702 generates a sonar control signal for controlling the sonar module. The sonar module generates an ultrasonic signal in accordance with the sonar control signal.

[0061] Further, based on the detection result of the second detection unit 704, the sonar control unit 702 determines the frequency modulation pattern applied to the ultrasonic wave and the transmission timing of the ultrasonic wave. The sonar control unit 702 is an example of a determination unit. For example, based on the detection result of the second detection unit 704, the sonar control unit 702 determines the frequency modulation pattern and the transmission timing for transmitting the ultrasonic wave, and generates a sonar control signal according to the determination.

[0062] The acquisition unit 703 acquires detection information and distance information from the sonar module. Specifically, the acquisition unit 703 acquires the detection information and distance information of the sonar module received via the I / F11D.

[0063] The second detection unit 704 detects an object existing in the transmission direction of the ultrasonic wave based on the reflected wave of the ultrasonic wave received by the sonar module. The second detection unit in this case is an example of an object detection unit.

[0064] Further, the second detection unit 704 detects, as interference, other ultrasonic waves transmitted from a transmission unit different from the sonar module of the vehicle 1 that transmitted the ultrasonic wave, based on the ultrasonic wave received by the sonar module. The second detection unit 704 in this case is an example of an interference detection unit. Here, in this specification, interference refers to a phenomenon in which ultrasonic waves overlap and reinforce or weaken each other.

[0065] Specifically, the second detection unit 704 detects the presence or absence of short-distance interference, the presence or absence of obstacles, and the presence or absence of long-distance interference based on the detection information and distance information of the sonar module acquired by the acquisition unit 703.

[0066] Hereinafter, with reference to FIGS. 9 to 33, the processes executed by the sensor control device 70 will be described with specific examples. In the following description, as shown in FIG. 9, a scene where the vehicle 1A and the vehicle 1B face each other backward will be described as an example.

[0067] The flow of processing in each part of the vehicle 1A according to the embodiment will be described using Figure 10. First, it is assumed that the driver of the vehicle 1A has performed an operation to put the gear into reverse. As a result, the battery outputs +B. The first detection unit 701 detects +B and detects that the vehicle 1A has started to move backward (process 7011).

[0068] The sonar control unit 702 generates a sonar control signal that controls the sonar 22 to transmit ultrasonic waves in accordance with a predetermined frequency modulation pattern and transmission timing (process 7021).

[0069] Specifically, the sonar control unit 702 sets the frequency modulation pattern to frequency modulation A and generates a sonar control signal according to a predetermined delay time. Note that in this embodiment, the predetermined frequency modulation pattern in process 7021 is frequency modulation A, but the predetermined frequency modulation pattern may also be frequency modulation B.

[0070] The sonar control unit 702 outputs the generated sonar control signal to the sonar 22a and the sonar 22c via the I / F 11D. Here, the sonar control unit 702 generates a sonar control signal for the sonar 22c so that the sonar 22c transmits ultrasonic waves after a certain period of time has elapsed since the sonar 22a transmitted ultrasonic waves.

[0071] The sonar 22a and the sonar 22c receive sonar control signals via the communication circuit 231. Then, the sonar 22a transmits ultrasonic waves based on the received sonar control signals (process 2221). Specifically, the sonar 22a transmits ultrasonic waves with a frequency modulation pattern of frequency modulation A and a normal delay time.

[0072] Here, after the sonar 22a transmits the ultrasonic waves, the vehicle control device 50 transmits a control signal (hereinafter also referred to as a reverse signal) for moving the vehicle 1A backward (process 501). In many conventional vehicles, a configuration is adopted in which the sonar transmits ultrasonic waves in response to the detection of a reverse signal.

[0073] In contrast, in this embodiment, the sonar 22a is configured to transmit ultrasonic waves in response to the detection of +B. Therefore, the sonar 22a can transmit ultrasonic waves earlier by the time indicated by the arrow AT in Fig. 10 than when the sonar transmits ultrasonic waves in response to the detection of a reverse signal. This allows for earlier detection of an obstacle.

[0074] Here, the processing flow of each part of the vehicle 1A according to the embodiment will be described with reference to FIG. 11. The horizontal axis in FIG. 11 represents the time axis. In the following drawings, when an arrow representing time is drawn, the horizontal axis also represents the time axis. After the sonar 22a transmits ultrasonic waves (process 2221), the sonar 22a performs a process of receiving reflected waves of the transmitted ultrasonic waves (process 2222). Furthermore, the sonar 22c performs a process of receiving reflected waves of the ultrasonic waves transmitted by the sonar 22a in process 2221 (process 2211). Furthermore, the sonar 22b performs a process of receiving reflected waves of the ultrasonic waves transmitted by the sonar 22a in process 2221 (process 2231).

[0075] Furthermore, after a certain time has elapsed since the sonar 22a transmitted the ultrasonic waves (process 2221), the sonar 22c transmits ultrasonic waves based on the received sonar control signal (process 2212). After the sonar 22c transmits the ultrasonic waves, the sonar 22c performs a process of receiving the reflected waves of the ultrasonic waves transmitted in process 2212 (process 2213).

[0076] The determination circuits 235 of the sonars 22a, 22c, and 22b compare the received signals with a short-distance interference detection threshold 810, an obstacle detection threshold 811, and a long-distance interference detection threshold 812, respectively, and calculate distance information.

[0077] The communication circuits 231 of the sonars 22a, 22c, and 22b transmit the distance information to the sensor control device 70. The sensor control device 70 receives the distance information via the I / F 11D, and the second detection unit 704 detects the presence or absence of an obstacle based on the distance information (process 7041).

[0078] In addition, in the present embodiment, in order to avoid false detection, the second detection unit 704 is configured to detect that there is an obstacle when the sonar module continuously receives the transmitted reflected wave a plurality of times (for example, three times). In the present embodiment, the condition for detecting an obstacle is that the reflected wave is continuously received three times.

[0079] Here, with reference to FIG. 12, the distance information calculation process of the determination circuit 235 of the sonar 22 and the obstacle detection process of the second detection unit 704 of the sensor control device 70 will be described. In the present embodiment, the received signal refers to a signal obtained by rectifying the received ultrasonic signal.

[0080] FIG. 12 shows the relationship between the received signal obtained by rectifying the reflected wave of the sonar 22a received in the process 2222 and the received signal obtained by rectifying the reflected wave of the sonar 22c received in the process 2211, the short-distance interference detection threshold 810, the obstacle detection threshold 811, the long-distance interference detection threshold 812, and the frequency modulation pattern A801 at the time of wave transmission.

[0081] The solid-line waveform in FIG. 12 represents an example of the received signal when an obstacle exists. Specifically, the received signal shown in FIG. 12 includes the received peak P1 indicating the presence of an obstacle.

[0082] In addition, the dotted-line waveform in FIG. 12 shows an example of the received signal when short-distance interference and long-distance interference occur due to the influence of ultrasonic waves emitted by other vehicles. When short-distance interference occurs in addition to the presence of an obstacle, two received peaks P2 and P1 will exist in the received signal. Also, when long-distance interference occurs in addition to the presence of an obstacle, two received peaks P1 and P3 will exist in the received signal.

[0083] Also, when short-distance interference and long-distance interference occur in addition to the presence of an obstacle, three received peaks P2, P1, and P3 will exist in the received signal.

[0084] For example, in the situation shown in FIG. 9, when interference occurs at a position closer to vehicle 1A than the position where vehicle 1B is present, sonar 22 receives interference waves such as ultrasonic waves emitted by the sonar 22 of vehicle 1B or reflected waves of the ultrasonic waves before receiving the reflected wave reflected by vehicle 1B. For this reason, P2 mainly representing short-distance interference by vehicle 1B appears before peak P1 representing the reflected wave reflected by vehicle 1B.

[0085] Also, in this case, since interference occurs at a position close to vehicle 1A, the amplitude of peak P2 is larger than the amplitude of peak P1 representing the reflected wave reflected by vehicle 1B. And as shown in FIG. 12, since the signal intensity at the peak position becomes smaller as the amplitude increases, the signal intensity is peak P1 > peak P2.

[0086] Note that the short-distance interference detection threshold 810 is a threshold of signal intensity for identifying whether it is short-distance interference. Specifically, based on the relationship of peak P1 > peak P2, a value smaller than the obstacle detection threshold 811 is set for the short-distance interference detection threshold 810.

[0087] Also, for example, in the situation of FIG. 9, when interference occurs at a position farther from the position where vehicle 1B is present, sonar 22 receives interference waves generated by multiple reflections after receiving the reflected wave reflected by vehicle 1B. For this reason, P3 mainly representing long-distance interference by multiple reflections exists after peak P1 representing the reflected wave reflected by vehicle 1B.

[0088] Also, in this case, since interference occurs at a position far from vehicle 1A, the amplitude of peak P3 is smaller than the amplitude of peak P1 representing the reflected wave reflected by vehicle 1B. And as shown in FIG. 12, since the signal intensity at the peak position becomes smaller as the amplitude increases, the signal intensity is peak P1 < peak P3.

[0089] Note that the long-distance interference detection threshold 812 is a signal strength threshold for identifying whether there is long-distance interference. Specifically, based on the relationship of peak P1 < peak P3, a value larger than the obstacle detection threshold 811 is set as the long-distance interference detection threshold 812.

[0090] Next, the calculation process of the distance information by the determination circuit 235 will be described. First, the determination circuit 235 compares the received signal with the obstacle detection threshold 811 and determines the presence or absence of a peak below the obstacle detection threshold 811. When there is a peak below the obstacle detection threshold 811, the determination circuit 235 determines the number of peaks below the obstacle detection threshold 811.

[0091] When there is one peak below the obstacle detection threshold 811, the determination circuit 235 determines that peak P1 or P2 exists. In this case, the determination circuit 235 determines the presence or absence of a peak below the short-distance interference detection threshold 810.

[0092] When there is one peak below the obstacle detection threshold 811 and the peak is below the short-distance interference detection threshold 810, the determination circuit 235 determines that peak P2 exists and calculates the distance value of A1K shown in FIG. 12 as the distance information.

[0093] On the other hand, when there is one peak below the obstacle detection threshold 811 and the peak is greater than or equal to the short-distance interference detection threshold 810, the determination circuit 235 determines that peak P1 exists. In this case, the determination circuit 235 determines whether there is a peak below the long-distance interference detection threshold 812 other than peak P1.

[0094] When there is one peak below the obstacle detection threshold 811 and there is a peak below the long-distance interference detection threshold 812 other than the peak, the determination circuit 235 determines that peaks P1 and P3 exist and calculates two distance values of A1 and A1E shown in FIG. 12 as the distance information.

[0095] On the other hand, if there is one peak below the obstacle detection threshold 811 and no other peaks below the long-distance interference detection threshold 812, the judgment circuit 235 determines that peak P1 exists and calculates the distance value of A1 shown in Figure 12 as distance information.

[0096] Furthermore, if there are two peaks below the obstacle detection threshold 811, the determination circuit 235 compares the received signal with the short-distance interference detection threshold 810 to determine whether there are any peaks below the short-distance interference detection threshold 810.

[0097] The sonar detects distance using ToF (Time of Flight). Also, since the height of the reflected wave attenuates depending on the distance, the thresholds may be set depending on the distance to the object.

[0098] If there are two peaks below the obstacle detection threshold 811 and at least one of the two peaks is below the short-distance interference detection threshold 810, the determination circuit 235 determines that peaks P2 and P1 are present. In this case, the determination circuit 235 determines that the peak with the largest amplitude is P2 and the peak with the next largest amplitude is P1, and calculates the two distance values A1K and A1 shown in FIG. 12 as distance information.

[0099] On the other hand, if there are two peaks below the obstacle detection threshold 811 and both of the two peaks are equal to or greater than the short-distance interference detection threshold 810, the determination circuit 235 determines that peaks P1 and P3 are present. In this case, the determination circuit 235 determines that the peak with the largest amplitude is P1 and the peak with the next largest amplitude is P3, and calculates the two distance values A1 and A1E shown in FIG. 12 as distance information.

[0100] Furthermore, if there are three or more peaks below the obstacle detection threshold 811, the determination circuit 235 determines whether there is a peak below the short-distance interference detection threshold 810.

[0101] If there are three or more peaks below the obstacle detection threshold 811, and at least one of the three or more peaks is below the short-distance interference detection threshold 810, the determination circuit 235 determines that peaks P2, P1, and P3 exist. At this time, the determination circuit 235 sets the peak with the largest amplitude as P2, the next largest amplitude peak as P1, and the next largest amplitude peak as P3, and calculates the three distance values of A1K, A1, and A1E shown in FIG. 12 as distance information.

[0102] Note that the determination circuit 235 does not have to detect as a peak the peaks that exist at a time later than peak P3.

[0103] On the other hand, if there are three or more peaks below the obstacle detection threshold 811 and all of the three or more peaks are equal to or higher than the short-distance interference detection threshold 810, the determination circuit 235 determines that P1 and P3 exist. At this time, the determination circuit 235 sets the peak with the largest amplitude as P1, and the next largest amplitude peak as P3, and calculates the two distance values of A1 and A1E shown in FIG. 12 as distance information.

[0104] Note that the determination circuit 235 does not have to detect as a peak the peaks that exist at a time later than peak P3.

[0105] Also, if there is no peak below the obstacle detection threshold 811, the determination circuit 235 determines the presence or absence of a peak below the long-distance interference detection threshold 812. If there is no peak below the obstacle detection threshold 811 and the amplitude of the portion with the largest amplitude among the received signals is below the long-distance interference detection threshold 812, the determination circuit 235 determines that peak P3 exists. The determination circuit 235 sets the said portion as peak P3, and calculates the distance value of A1E shown in FIG. 12 as distance information.

[0106] On the other hand, if there is no peak below the obstacle detection threshold 811 and the amplitude of the portion with the largest amplitude among the received signals is equal to or higher than the long-distance interference detection threshold 812, the determination circuit 235 uses the information indicating that all of the distance values of A1K, A1, and A1E have not been calculated as the distance information.

[0107] The distance information calculated by the determination circuit 235 is sent to the communication circuit 231. The communication circuit 231 transmits the distance information sent by the determination circuit 235 to the sensor control device 70. Then, the transmitted distance information is acquired by the acquisition unit 703 of the sensor control device 70.

[0108] Note that FIG. 12 described the received signal obtained by rectifying the reflected wave of the sonar 22a received in the process 2222 and the received signal obtained by rectifying the reflected wave of the sonar 22c received in the process 2211. The received signal obtained by rectifying the reflected wave of the second center sonar 22b received in the process 2231 is the same as that in FIG. 12.

[0109] Next, the obstacle detection process by the second detection unit 704 will be described. In the example of the process 7041 in FIG. 11, the second detection unit 704 detects the presence or absence of an obstacle based on the distance information calculated from the received signals obtained by rectifying the reflected waves received in the processes 2222, 2211, and 2231.

[0110] Specifically, in all of the received signals received in the processes 2222, 2211, and 2231, when the distance value of A1 is calculated, the second detection unit 704 detects that there is an obstacle around the vehicle 1A. On the other hand, in other cases, the second detection unit 704 detects that there is no obstacle around the vehicle 1A.

[0111] Note that when the difference between the calculated distance values of A1 based on the received signals obtained by rectifying the reflected waves received in the processes 2222, 2211, and 2231 exceeds a predetermined threshold value, the second detection unit 704 may detect that there is no obstacle around the vehicle 1A even if the distance value of A1 is calculated in all of the received signals received in the processes 2222, 2211, and 2231.

[0112] Returning to FIG. 11, the description continues. The sonar control unit 702 generates a sonar control signal based on the detection result of the second detection unit 704 in process 7041 (process 7022). Specifically, when the second detection unit 704 detects that there is no obstacle, the sonar control unit 702 sets the frequency modulation pattern to frequency modulation A and generates a sonar control signal to control sonar 22 to transmit ultrasonic waves according to a predetermined delay time.

[0113] On the other hand, when the second detection unit 704 detects the presence of an obstacle, the sonar control unit 702 determines the frequency modulation pattern to be frequency modulation A and generates a sonar control signal according to a predetermined delay time. In this embodiment, in process 7022, the frequency modulation pattern when an obstacle is detected is set to frequency modulation A, but the frequency modulation pattern when an obstacle is detected may be set to frequency modulation B.

[0114] Here, in the example of FIG. 11, in process 7041, the second detection unit 704 detects an obstacle, and in process 7022, the frequency modulation pattern is set to frequency modulation A, and a sonar control signal is generated to control sonar 22 to transmit ultrasonic waves according to a predetermined delay time.

[0115] Also, in process 7022 of FIG. 11, the sonar control unit 702 transmits the generated sonar control signal to sonar 22b and sonar 22d via I / F11D. Here, for sonar 22d, the sonar control unit 702 generates a sonar control signal to transmit the first ultrasonic wave after a certain period has elapsed after sonar 22b transmits the first ultrasonic wave.

[0116] Sonar 22b and sonar 22d receive the sonar control signal via communication circuit 231. Then, sonar 22b transmits the first ultrasonic wave according to the received sonar control signal (process 2232). Specifically, sonar 22b transmits the first ultrasonic wave with the frequency modulation pattern of frequency modulation A and a normal delay time.

[0117] Here, with reference to FIG. 13, the processing flow of each part of the vehicle 1A according to the embodiment will be described. After the sonar 22b transmits ultrasonic waves, the sonar 22b performs a process of receiving the reflected wave of the first ultrasonic wave transmitted (process 2233). Also, the sonar 22d performs a process of receiving the reflected wave of the first ultrasonic wave transmitted by the sonar 22b (process 2241).

[0118] Also, the sonar 22a performs a process of receiving the reflected wave of the first ultrasonic wave transmitted by the sonar 22b (process 2223).

[0119] Also, after a certain period of time has elapsed since the first ultrasonic wave transmission by the sonar 22b, the sonar 22d transmits the first ultrasonic wave according to the received sonar control signal (process 2242). After the sonar 22d transmits the ultrasonic waves, the sonar 22d performs a process of receiving the reflected wave of the first ultrasonic wave transmitted (process 2243).

[0120] The determination circuits 235 of the sonar 22a, the sonar 22c, and the sonar 22b respectively compare the received signals with the short - distance interference detection threshold 810, the obstacle detection threshold 811, and the long - distance interference detection threshold 812, and calculate the distance information.

[0121] The communication circuits 231 of the sonar 22a, the sonar 22c, and the sonar 22b transmit the distance information to the sensor control device 70. The sensor control device 70 receives the distance information via the I / F11D, and the second detection unit 704 detects interference based on the distance information (process 7042).

[0122] Here, with reference to FIG. 14, the distance information calculation process of the determination circuit 235 of the sonar 22 and the interference detection process of the second detection unit 704 of the sensor control device 70 will be described.

[0123] FIG. 14 shows the relationship between the received signal obtained by rectifying the reflected wave of sonar 22b received in process 2233, the received signal obtained by rectifying the reflected wave of sonar 22d received in process 2241, the short-distance interference detection threshold 810, the obstacle detection threshold 811, and the long-distance interference detection threshold 812, and the frequency modulation pattern A821 or frequency modulation B822 during transmission.

[0124] The process of determination circuit 235 is substantially the same as in the case of FIG. 12. However, after the processes of process 2233, process 2241, and process 2223, determination circuit 235 calculates the distance value of A2 or B2 instead of the distance value of A1, the distance value of A2K or B2K instead of A1K, and the distance value of A2E or B2E instead of the distance value of A1E.

[0125] When sonar 22b and sonar 22d transmit waves with frequency modulation A, determination circuit 235 calculates A2, A2K, and A2E. When sonar 22b and sonar 22d transmit waves with frequency modulation B, determination circuit 235 calculates B2, B2K, and B2E.

[0126] Next, the interference detection process by the second detection unit 704 will be described. In the example of process 7042 in FIG. 13, first, the second detection unit 704 detects the presence or absence of short-distance interference, the presence or absence of an obstacle, and the presence or absence of long-distance interference based on the distance information calculated from the received signals obtained by rectifying the reflected waves received in process 2233, process 2241, and process 2223.

[0127] Specifically, in all of the received signals obtained by rectifying the reflected waves received in process 2233, process 2241, and process 2223, if the distance value of A2K or B2K is calculated, the second detection unit 704 detects that there is short-distance interference in vehicle 1A. On the other hand, in other cases, the second detection unit 704 detects that there is no short-distance interference in vehicle 1A.

[0128] Furthermore, if the distance value of A2 or B2 is calculated in all of the received signals obtained by rectifying the reflected waves received in process 2233, process 2241, and process 2223, the second detection unit 704 detects that an obstacle exists around the vehicle 1A. On the other hand, in cases other than those mentioned above, the second detection unit 704 detects that no obstacle exists around the vehicle 1A.

[0129] Furthermore, if an A2E or B2E distance value is calculated for all of the received signals obtained by rectifying the reflected waves received in process 2233, process 2241, and process 2223, the second detection unit 704 detects that long-distance interference is present in vehicle 1A. On the other hand, in cases other than those mentioned above, the second detection unit 704 detects that long-distance interference is not present in vehicle 1A.

[0130] Then, the second detection unit 704 detects an interference pattern used to determine the frequency modulation pattern (frequency modulation A or frequency modulation B) and transmission timing (no delay time or extended delay time) of the ultrasonic waves to be transmitted next, based on the distance values of A1, A1K, A1E, A2 (or B2), A2K (or B2K), and A2E (or B2E).

[0131] 15 to 32, the detection process of the interference pattern by the second detection unit 704 will be described. Fig. 15 shows a change in the positional relationship of interference between vehicle 1A and vehicle 1B when vehicle 1A shown in Fig. 9 moves backward in the direction where vehicle 1B is present (negative direction of the X axis in Fig. 9), and vehicle 1B moves backward in the direction where vehicle 1A is present (positive direction of the X axis in Fig. 9).

[0132] As shown in Figure 15, when vehicle 1A starts to move backward toward vehicle 1B, and vehicle 1B starts to move backward toward vehicle 1A, and sonar 22a of vehicle 1A transmits ultrasonic waves, the ultrasonic waves reach the rear end of vehicle 1B after transmission time ST has elapsed.

[0133] Then, the reflected wave reflected by the rear end of vehicle 1B is received by sonars 22a and 22c of vehicle 1A after an additional reflection time RT has elapsed from that point. Therefore, the determination circuit 235 of sonars 22a and 22c of vehicle 1A calculates the distance value of A1, for example, the distance value to vehicle 1B.

[0134] Also, sonars 22a and 22c of vehicle 1A receive the ultrasonic wave transmitted from vehicle 1B before the transmission time ST has elapsed. For this reason, near-distance interference KK occurs. Therefore, the determination circuit 235 of sonars 22a and 22c of vehicle 1A calculates the distance value of A1K, for example, the distance value related to the near-distance interference KK.

[0135] After that, when sonar 22b of vehicle 1A further transmits an ultrasonic wave, the ultrasonic wave reaches the rear end of vehicle 1B after the transmission time ST has elapsed. Then, after an additional reflection time RT has elapsed from that point, the reflected wave is received by sonars 22b and 22d. Therefore, the determination circuit 235 of sonars 22 b and sonar 22 d of vehicle 1A calculates the distance value of A2, for example, the distance value to vehicle 1B.

[0136] Also, sonars 22b and 22d of vehicle 1A receive the ultrasonic wave transmitted from vehicle 1B before the transmission time ST has elapsed. For this reason, near-distance interference KK occurs. Therefore, the determination circuit 235 of sonars 22b and 22d of vehicle 1A calculates the distance value of A2K, for example, the distance value related to the near-distance interference KK.

[0137] Also, since vehicle 1A is moving backward in the direction of vehicle 1B and vehicle 1B is moving backward in the direction of vehicle 1A, the distance between vehicle 1A and vehicle 1B is closer at the time when sonar 22b of vehicle 1A transmits an ultrasonic wave than at the time when sonar 22a of vehicle 1A transmits an ultrasonic wave. Therefore, the distance value of A2 is smaller than that of A1, and the distance value of A2K is smaller than that of A1K.

[0138] Therefore, as time passes, vehicle 1B approaches vehicle 1A, and the position where short-distance interference KK occurs (hereinafter also referred to as the interference position) also approaches vehicle 1A.

[0139] In addition, when long-distance interference EK occurs due to multiple reflections or the like, the interference position of long-distance interference EK also approaches vehicle 1A as time passes, similar to the case of the above short-distance interference KK.

[0140] FIG. 16 shows the change in the positional relationship of the interference between vehicle 1A and vehicle 1B when vehicle 1A shown in FIG. 9 moves in the direction opposite to the direction in which vehicle 1B exists (the positive direction of the X axis in FIG. 9), and vehicle 1B moves in the direction opposite to the direction in which vehicle 1A exists (the negative direction of the X axis in FIG. 9).

[0141] In FIG. 16, since vehicle 1A moves in the direction opposite to vehicle 1B and vehicle 1B moves in the direction opposite to vehicle 1A, the distance between vehicle 1A and vehicle 1B is farther at the time when sonar 22b of vehicle 1A transmits ultrasonic waves than at the time when sonar 22a of vehicle 1A transmits ultrasonic waves. Therefore, the distance value of A2 is larger than that of A1, and the distance value of A2K is larger than that of A1K.

[0142] Therefore, as time passes, vehicle 1B moves away from vehicle 1A, and the interference position of short-distance interference also moves away from vehicle 1A.

[0143] In addition, when long-distance interference EK occurs, the interference position of long-distance interference EK also moves away from vehicle 1A as time passes, similar to the case of the above short-distance interference KK.

[0144] As described above, the relationships explained with reference to FIGS. 15 and 16 hold for the vehicle 1A, the obstacle, the interference positions of the vehicle 1A and the short-distance interference KK, and the interference positions of the vehicle 1A and the long-distance interference. From this, the second detection unit 704 compares the distance value of A1 with the distance value of A2 (or B2), the distance value of A1K with the distance value of A2K (or B2K), and the distance value of A1E with the distance value of A2E (or B2E), and detects an interference pattern representing the relationship between the position of the vehicle 1A, the interference position of the short-distance interference, the position of the obstacle, and the interference position of the long-distance interference.

[0145] In this embodiment, the distance values of A1, A1K, and A1E used for detecting the interference pattern are assumed to be the values obtained from the sonar 22a. However, the values obtained from the sonar 22c, the values obtained from the sonar 22b, or the average value or median value of the values obtained from the sonar 22a may also be used.

[0146] Also, the distance values of A2 (or B2), A1K, A2K (or B2K), A1K, and A2K (or B2K) are assumed to be the values obtained from the sonar 22b. However, the values obtained from the sonar 22d, the values obtained from the sonar 22a, or the average value or median value of the values obtained from the sonar 22a may also be used.

[0147] Further, the sonar control unit 702 generates a sonar control signal based on the interference pattern detected by the second detection unit 704.

[0148] Hereinafter, the detection process of the interference pattern by the second detection unit 704 and the determination process (hereinafter also referred to as the transmission condition of the ultrasonic wave) of the type of frequency modulation (frequency modulation A or frequency modulation B) and the transmission timing (earlier or later) of the ultrasonic wave to be transmitted next by the sonar control unit 702 will be described.

[0149] In this embodiment, the second detection unit 704 detects an interference pattern based on a data table that determines the detection of an interference pattern and the transmission conditions of the next ultrasonic wave to be transmitted, and that is stored in the flash memory 11E, etc. Also, the sonar control unit 702 determines the transmission conditions of the next ultrasonic wave to be transmitted based on the data table.

[0150] "No." in the data tables of Figures 17 and 18 represents a number that identifies the interference pattern. Also, "Sonar 22a / 22c (frequency modulation A or frequency modulation B)" in "Interference pattern" represents the source of the first ultrasonic wave and the frequency modulation pattern used for transmitting the ultrasonic wave. Also, "Sonar 22b / 22d (frequency modulation A or frequency modulation B)" in "Interference pattern" represents the source of the second ultrasonic wave and the frequency modulation pattern used for transmitting the ultrasonic wave.

[0151] Additionally, "Sonar 22a / 22c" in "Transmission Conditions" indicates the source of the third ultrasonic wave. Additionally, "Frequency Modulation" in "Transmission Conditions" indicates the frequency modulation pattern used for transmitting the third ultrasonic wave. Additionally, "Transmission Timing" in "Transmission Conditions" indicates whether the timing of transmitting the third ultrasonic wave is to be advanced or delayed.

[0152] In this embodiment, "advancing the transmission timing" means that the sonar 21 or the sonar 22 transmits ultrasonic waves without a predetermined normal delay time. Also, "delaying the transmission timing" means that the sonar 21 or the sonar 22 transmits ultrasonic waves by extending the predetermined normal delay time by a predetermined time.

[0153] In addition, the "short-range interference" of "sonar 22a / 22c (frequency modulation A)" in the "interference pattern" indicates whether or not the distance value of A1K has been measured (whether or not short-range interference has been detected). In addition, the "obstacle" of "sonar 22a / 22c (frequency modulation A)" in the "interference pattern" indicates whether or not the distance value of A1 has been measured (whether or not an obstacle has been detected). In addition, the "long-range interference" of "sonar 22a / 22c (frequency modulation A)" in the "interference pattern" indicates whether or not the distance value of A1E has been measured (whether or not long-range interference has been detected).

[0154] In addition, the "short-range interference" of "sonar 22b / 22d (frequency modulation A)" in the "interference pattern" represents the relationship between the distance value of A1K and the distance value of A2K (or B2K). In addition, the "obstacle" of "sonar 22b / 22d (frequency modulation A)" in the "interference pattern" represents the relationship between the distance value of A1 and the distance value of A2 (or B2). In addition, the "long-range interference" of "sonar 22b / 22d (frequency modulation A)" in the "interference pattern" represents the relationship between the distance value of A1E and the distance value of A2E (or B2E).

[0155] Here, Fig. 17 is an excerpt from the data table according to this embodiment that shows the interference pattern when the distance value of A1 is measured, and Fig. 18 is an excerpt from the data table according to this embodiment that shows the interference pattern when the distance value of A1 is not measured.

[0156] The second detection unit 704 refers to the data table and identifies the interference pattern from the distance values of A1, A1K, A1E, A2 (or B2), A2K (or B2K), and A2E (or B2E) acquired as distance information by the acquisition unit 703. For example, if the acquisition unit 703 acquires the distance value of A1 and the distance value of A2, but does not acquire other distance values, and the distance value of A1 is greater than the distance value of A2, the second detection unit 704 refers to the data table and identifies the interference pattern as "No. 1."

[0157] Also, in this case, the sonar control unit 702 refers to the data table and determines the frequency modulation "frequency modulation A " and the transmission timing "earlier" as the transmission conditions corresponding to the interference pattern "No. 1".

[0158] Here, the reason why the data table is set as shown in FIGS. 17 and 18 will be described with reference to FIGS. 19 to 29. In FIGS. 19 to 29, the obstacle is assumed to be another vehicle.

[0159] "Sonar 22a / Sonar 22c: first time" in FIG. 19 represents the first transmission and reception of ultrasonic waves by Sonar 22a / Sonar 22c. Also, "Sonar 22b / Sonar 22d: first time" represents the first transmission and reception of ultrasonic waves by Sonar 22b / Sonar 22d. Further, "Sonar 22a / Sonar 22c: second time" in FIG. 19 represents the second transmission and reception of ultrasonic waves by Sonar 22a / Sonar 22c under the transmission conditions determined based on the reception result of the ultrasonic waves transmitted for the first time.

[0160] For comparison with the determined transmission conditions, an example of the case where the second transmission and reception of ultrasonic waves are performed with a predetermined delay time is shown by the dotted line "delay "Nobu" ," and "transmission".

[0161] In the interference pattern "No. 1", the distance value of A1 is measured during the first transmission of ultrasonic waves, the distance value of A2 is measured during the second transmission of ultrasonic waves, and the situation is such that the distance value of A1 > the distance value of A2. This indicates that another vehicle is approaching Vehicle 1. Also, since the distance values of A1K and AIE are not measured, it can be seen that neither short-distance interference nor long-distance interference has occurred.

[0162] In this case, since another vehicle is approaching Vehicle 1, there is a possibility that Vehicle 1 and the other vehicle will collide, and it is necessary to detect the other vehicle earlier. Therefore, the sensor control device 70 advances the ultrasonic wave transmission timing. As a result, an obstacle can be detected earlier. For this reason, the sensor control device 70 can reduce the possibility of a collision between Vehicle 1 and the other vehicle by detecting the other vehicle early and notifying the driver of a warning.

[0163] Therefore, in the interference pattern "No. 1", the transmission timing is advanced. In the present embodiment, when advancing the transmission timing, it is defined that the frequency modulation pattern is frequency modulation A, and when delaying the transmission timing, the frequency modulation pattern is frequency modulation B. Therefore, in this case, the frequency modulation pattern A becomes.

[0164] In the interference pattern "No. 2" shown in FIG. 20, the distance value of A1 is measured by the first ultrasonic wave transmission, the distance value of A2 is measured by the second ultrasonic wave transmission, and the situation is such that the distance value of A1 ≤ the distance value of A2. This indicates that the other vehicle is moving away from Vehicle 1. Also, since the distance values of A1K and AIE are not measured, it can be seen that neither short-distance interference nor long-distance interference has occurred.

[0165] In this case, since the other vehicle is moving away from Vehicle 1, the possibility of a collision between Vehicle 1 and the other vehicle is low. Therefore, the sensor control device 70 delays the ultrasonic wave transmission timing. As a result, an obstacle farther away can be detected. For this reason, the sensor control device 70 can detect the other vehicle even when the other vehicle moves further away. Therefore, in the interference pattern "No. 2", the transmission timing is delayed.

[0166] The interference pattern "No.3" shown in Fig. 21 is a situation where the distance value of A1 is measured during the first ultrasonic wave transmission, and no distance values are measured during the second ultrasonic wave transmission. This indicates that no other vehicles are detected during the second ultrasonic wave transmission. Also, since the distance values of A1K and AIE are not measured, it can be seen that neither short-distance interference KK nor long-distance interference EK has occurred.

[0167] In this case, since no other vehicles are detected, the transmission timing can be advanced or delayed. However, in order to determine what to do with the transmission timing when the distance value of A2 is not measured, in the data table of Fig. 17, it is determined that the transmission timing is advanced when the distance value of A2 is not measured. Therefore, in the interference pattern "No.3", the transmission timing is advanced.

[0168] The interference pattern "No.4" shown in Fig. 22 is a situation where the distance value of A1 is measured during the first ultrasonic wave transmission, and the distance values of A2K and A2 are measured during the second ultrasonic wave transmission, and the distance value of A1 > becomes the distance value of A2. This indicates that there is short-distance interference KK and that other vehicles are moving away from Vehicle 1.

[0169] In this case, since short-distance interference KK has occurred, by transmitting the ultrasonic wave later, the time until the ultrasonic wave reaches the interference position of short-distance interference KK can be lengthened. Thereby, the possibility of interference by the ultrasonic wave transmitted by other vehicles can be reduced. Therefore, in the interference pattern "No.4", the transmission timing is delayed.

[0170] The interference pattern "No.5" shown in Fig. 23 is a situation where the distance value of A1 is measured during the first ultrasonic wave transmission, and the distance values of A2K and A2 are measured during the second ultrasonic wave transmission, and the distance value of A1 ≦ becomes the distance value of A2. This indicates that there is short-distance interference KK and that other vehicles are approaching Vehicle 1.

[0171] In this case, since short-distance interference KK occurs, as in the interference pattern "No. 4", in the interference pattern "No. 5", the transmission timing is set to be delayed.

[0172] In the interference pattern "No. 6" shown in FIG. 24, the distance value of A1 is measured at the first ultrasonic wave transmission, and the distance values of A2K are measured at the second ultrasonic wave transmission. 、A The two distance values is not measured This is the situation. This indicates that there is short-distance interference KK and no other vehicle is detected at the second ultrasonic wave transmission.

[0173] In this case, since short-distance interference KK occurs, as in the interference pattern "No. 4", in the interference pattern "No. 6 」, the transmission timing is set to be delayed.

[0174] In the interference pattern "No. 7" shown in FIG. 25, the distance value of A1 is measured at the first ultrasonic wave transmission, and the distance values of A2 and A2E are measured at the second ultrasonic wave transmission, and the distance value of A1 > the distance value of A2. This indicates that there is long-distance interference EK and another vehicle is approaching vehicle 1.

[0175] In this case, although long-distance interference EK occurs, the influence of long-distance interference is small, and since another vehicle is approaching vehicle 1, as in the interference pattern "No. 1", in the interference pattern "No. 7", the transmission timing is set to be advanced.

[0176] In the interference pattern "No. 8" shown in FIG. 26, the distance value of A1 is measured at the first ultrasonic wave transmission, and the distance values of A2 and A2E are measured at the second ultrasonic wave transmission, and the distance value of A1 ≤ the distance value of A2. This indicates that there is long-distance interference EK and another vehicle is moving away from vehicle 1.

[0177] In this case, long-distance interference EK occurs, but the influence of the long-distance interference is small, and since other vehicles are far from Vehicle 1, in the interference pattern "No. 8", similar to the interference pattern "No. 2", the transmission timing is Slow set to be

[0178] In the interference pattern "No. 9" shown in FIG. 27, the distance value of A1 is measured by the first ultrasonic wave transmission, and the distance value of A2E is measured by the second ultrasonic wave transmission 、A These two distance values is not measured are the situation. This indicates that there is long-distance interference EK and no other vehicles are detected by the second ultrasonic wave transmission.

[0179] In this case, long-distance interference EK occurs, short-distance interference KK is not detected, and no other vehicles are detected by the second ultrasonic wave transmission. Therefore, even if the interference position of the detected long-distance interference EK moves away by delaying the ultrasonic wave transmission, the long-distance interference EK can still be detected. For this reason, in the interference pattern "No. 9", the transmission timing is set to be delayed.

[0180] Also, for the interference patterns "No. 10", "No. 11", and "No. 12", the influence of the long-distance interference EK is small, and the transmission conditions are determined according to the same judgment as the interference patterns "No. 4", "No. 5", and "No. 6" respectively, so the illustration and description are omitted.

[0181] Also, since the influence of the short-distance interference KK is large, when both the distance value of A1K and the distance value of A2K are calculated as in the interference patterns "No. 13" to "No. 18", the transmission conditions are determined based on the relationship between the distance value of A1K and the distance value of A2K.

[0182] Here, as shown in interference patterns "No. 13" to "No. 15", the distance value of A1K <A2Kの距離値となる場合、他車の干渉が遅くなるため、送波タイミングを早くすることにより、他の車両が送波した超音波による干渉が起こる可能性を低減できる。このため、A1Kの距離値<A2Kの距離値となる場合には、送波タイミングを早くすることとしている。

[0183] On the other hand, when the distance value of A1K is greater than or equal to the distance value of A2K, as in interference patterns "No. 16" to "No. 18," interference from other vehicles occurs earlier, so by delaying the transmission timing, the possibility of interference from ultrasonic waves transmitted by other vehicles can be reduced. For this reason, when the distance value of A1K is greater than or equal to the distance value of A2K, the transmission timing is delayed.

[0184] Furthermore, when the distance values of A1K and A2K are not measured, but the distance values of A1, A2, A1E, and A2E are measured, as in interference patterns "No. 19," "No. 20," "No. 22," and "No. 23," the influence of long-distance interference EK is small, and therefore the transmission conditions are determined based on the relationship between the distance values of A1 and A2.

[0185] Therefore, interference patterns "No. 19" and "No. 22" are judged in the same way as interference pattern "No. 1," and therefore the transmission timing is advanced for interference patterns "No. 19" and "No. 22."

[0186] In addition, interference patterns "No. 20" and "No. 23" are interference patterns "No. 2 For interference patterns "No. 19" and "No. 22", the transmission timing is Slow We are planning to do this.

[0187] Additionally, interference patterns "No. 21" and "No. 24" represent situations where the distance values of A1E and A2E are measured. In this case, the transmission conditions are determined based on the relationship between the distance values of A1E and A2E.

[0188] Here, as shown in interference pattern "No. 21", the distance value of A1E <A2Eの距離値となる場合、他車の干渉が遅くなるため、送波タイミングを早くすることにより、他の車両が送波した超音波による干渉が起こる可能性を低減できる。このため、AIEの距離値及びA2Eの距離値以外は計測されず、A1Eの距離値<A2Eの距離値となる場合には、送波タイミングを早くすることとしている。

[0189] On the other hand, when the distance value of A1E is greater than or equal to the distance value of A2E, as in interference pattern "No. 24," interference from other vehicles occurs earlier, so by delaying the transmission timing, the possibility of interference from ultrasonic waves transmitted by other vehicles can be reduced. For this reason, only the distance values of AIE and A2E are measured, and when the distance value of A1E is greater than or equal to the distance value of A2E, the transmission timing is delayed.

[0190] Furthermore, for interference patterns "No. 25" to "No. 30," both the A1K distance value and the A2K distance value are calculated, and therefore, similar to interference patterns "No. 13" to "No. 18," the transmission conditions are determined based on the relationship between the A1K distance value and the A2K distance value.

[0191] Therefore, interference patterns "No. 25" to "No. 27" are the distance values of A1K. <A2Kの距離値となるため、送波タイミングを早くすることとしている。また、干渉パターン「No.28」乃至「No.30」は、A1Kの距離値≧A2Kの距離値となるため、送波タイミングを遅くすることとしている。

[0192] In addition, since the interference patterns "No. 31" to "No. 33" are subject to the same judgment as the interference patterns "No. 22" to "No. 24", for the interference pattern "No. 31", similar to the interference pattern "No. 22", the transmission timing is set to be earlier. Also, for the interference patterns "No. 32" and "No. 33", similar to the interference patterns "No. 23" and "No. 24", the transmission timing is set to be later.

[0193] In addition, since the interference patterns "No. 34" to "No. 36" are subject to the same judgment as the interference patterns "No. 19" to "No. 21", for the interference patterns "No. 34" and "No. 36", similar to the interference patterns "No. 19" and "No. 21", the transmission timing is set to be earlier. Also, for the interference pattern "No. 35", similar to the interference pattern "No. 20", the transmission timing is set to be later.

[0194] In addition, for the interference patterns "No. 3 7 " to "No. 48", since both the distance value of A1K and the distance value of A2K are calculated, the transmission conditions are determined based on the relationship between the distance value of A1K and the distance value of A2K.

[0195] Therefore, for the interference patterns "No. 3 7 " to "No. 42", since the distance value of A1K < the distance value of A2K, the transmission timing is set to be earlier. Also, for the interference patterns "No. 43" to "No. 48", since the distance value of A1K ≥ the distance value of A2K, the transmission timing is set to be later.

[0196] The interference patterns in the case where another vehicle is detected by the first ultrasonic wave transmission shown in FIG. 17 have been described above. Below, the interference patterns in the case where another vehicle is not detected by the first ultrasonic wave transmission shown in FIG. 18 will be described.

[0197] The interference pattern "No.49" shown in Fig. 28 is a situation where the distance value of A1K is measured by the first ultrasonic wave transmission, the distance values of B2K and B2 are measured by the second ultrasonic wave transmission, and the distance value of A1K < the distance value of B2K. This indicates that the interference from other vehicles is delayed. That is, no other vehicle was detected by the first ultrasonic wave transmission, but another vehicle was detected by the second ultrasonic wave transmission.

[0198] In this case, since the interference from other vehicles is delayed, by advancing the transmission timing, the possibility of interference caused by the ultrasonic waves transmitted by other vehicles can be reduced. Therefore, for the interference pattern "No.49", the transmission timing is advanced.

[0199] Note that since the influence of short - range interference KK is significant, when both the distance value of A1K and the distance value of B2K are calculated as in the interference pattern "No.49", the transmission conditions are determined based on the relationship between the distance value of A1K and the distance value of B2K.

[0200] The interference pattern "No.50" shown in Fig. 29 is a situation where the distance value of A1K is measured by the first ultrasonic wave transmission, the distance values of B2K and B2 are measured by the second ultrasonic wave transmission, and the distance value of A1K ≥ the distance value of B2K. This indicates that the interference from other vehicles is early. That is, no other vehicle was detected by the first ultrasonic wave transmission, but another vehicle was detected by the second ultrasonic wave transmission.

[0201] In this case, since the interference from other vehicles is early, by delaying the transmission timing, the possibility of interference caused by the ultrasonic waves transmitted by other vehicles can be reduced. Therefore, for the interference pattern "No.50", the transmission timing is delayed.

[0202] Also, since the interference pattern "No.51" has the same judgment as the interference pattern "No.49", for the interference pattern "No.51", similar to the interference pattern "No.49", the transmission timing is advanced.

[0203] Also, since the interference pattern "No.52" has the same judgment as the interference pattern "No.50", in the interference pattern "No.52", the transmission timing is set to be slower, similar to the interference pattern "No.50".

[0204] Also, when neither the distance value of B2K nor the distance value of B2E is measured, and the distance value of A1K is measured, as in the interference patterns "No.53" and "No.54", since near - distance interference KK is detected when ultrasonic waves are transmitted with frequency modulation A, in the interference patterns "No.53" and "No.54", the frequency modulation pattern is set to frequency modulation B. Therefore, the transmission timing in this case becomes slower.

[0205] Also, when the distance value of B2K is not measured and the distance values of A1E and B2E are measured, as in the interference patterns "No.55" and "No.58", since long - distance interference EK occurs, the transmission conditions are determined based on the relationship between the distance value of A1E and the distance value of B2E.

[0206] Here, when the distance value of A1E < the distance value of B2E, as in the interference patterns "No.55" and "No.57", the interference from other vehicles is delayed. Therefore, by advancing the transmission timing, the possibility of interference caused by ultrasonic waves transmitted by other vehicles can be reduced. For this reason, when the distance value of A1E < the distance value of B2E, the transmission timing is set to be advanced.

[0207] On the other hand, when the distance value of A1E ≥ the distance value of A2E, as in the interference patterns "No.56" and "No.58", the interference from other vehicles is advanced. Therefore, by delaying the transmission timing, the possibility of interference caused by ultrasonic waves transmitted by other vehicles can be reduced. For this reason, when the distance value of A1E ≥ the distance value of B2E, the transmission timing is set to be delayed.

[0208] In addition, for interference patterns "No. 59" to "No. 70", since both the distance value of A1K and the distance value of B2K are calculated, similar to interference patterns "No. 49" and "No. 50", the transmission conditions are determined based on the relationship between the distance value of A1K and the distance value of B2K.

[0209] Therefore, for interference patterns "No. 59" to "No. 64", since the distance value of A1K < the distance value of A2K, the transmission timing is set to be earlier. Also, for interference patterns "No. 65" to "No. 70", since the distance value of A1K ≥ the distance value of B2K, the transmission timing is set to be later.

[0210] In addition, for interference patterns "No. 71" to "No. 74", since the same judgment as for interference patterns "No. 55" to "No. 58" is made, in interference patterns "No. 71" and "No. 72", similar to interference patterns "No. 55" and "No. 57", the transmission timing is set to be earlier. Also, in interference patterns "No. 73" and "No. 74", similar to interference patterns "No. 56" and "No. 58", the transmission timing is set to be later.

[0211] Returning to FIG. 13 and continuing the explanation. After the second detection unit 704 detects the interference pattern in process 7042, the sonar control unit 702 determines the frequency modulation pattern of the ultrasonic wave and the transmission timing of the ultrasonic wave that the sonar 22a transmits for the second time based on the interference pattern.

[0212] Specifically, the sonar control unit 702 determines whether to transmit the ultrasonic wave with frequency modulation A or frequency modulation B. Also, when the sonar control unit 702 determines to transmit with frequency modulation A, it determines to transmit the ultrasonic wave without a delay time. Also, when the sonar control unit 702 determines to transmit with frequency modulation B, it determines to transmit the ultrasonic wave after extending a predetermined delay time.

[0213] Then, the sonar control unit 702 generates a sonar control signal for controlling the sonar 22 to transmit ultrasonic waves according to the determined type of frequency modulation and delay time (process 7023). In the example of FIG. 13, it is assumed that the sonar control unit 702 generates a sonar control signal for controlling the sonar 22 to transmit ultrasonic waves with frequency modulation B and an extended delay time.

[0214] The sonar control unit 702 transmits the generated sonar control signal to the sonar 22a and the sonar 22c via the I / F 11D. Here, for the sonar 22c, the sonar control unit 702 generates a sonar control signal for transmitting ultrasonic waves after a certain period has elapsed after the sonar 22a has transmitted ultrasonic waves.

[0215] The sonar 22a and the sonar 22c receive the sonar control signal via the communication circuit 231. Then, the sonar 22a transmits the second ultrasonic wave according to the received sonar control signal (process 2224). Specifically, the sonar 22a transmits ultrasonic waves with the frequency modulation pattern of frequency modulation B and an extended delay time.

[0216] Here, with reference to FIG. 30, the processing flow of each part of the vehicle 1A will be described. After the second ultrasonic wave is transmitted by the sonar 22a, the sonar 22a performs a process of receiving the reflected wave of the second transmitted ultrasonic wave (process 2225). Also, the sonar 22c performs a process of receiving the reflected wave of the second ultrasonic wave transmitted by the sonar 22a (process 221 4 )).

[0217] Also, the sonar 22b receives the reflected wave of the second ultrasonic wave transmitted by the sonar 22a (process 2234).

[0218] Also, after a certain time has elapsed since the second ultrasonic wave is transmitted by the sonar 22a, the sonar 22c transmits ultrasonic waves according to the received sonar control signal (process 2215). After the second ultrasonic wave is transmitted by the sonar 22c, the sonar 22c performs a process of receiving the reflected wave of the second transmitted ultrasonic wave (process 2216).

[0219] The determination circuits 235 of the sonars 22a, 22c, and 22b compare the received signals with a short-distance interference detection threshold 810, an obstacle detection threshold 811, and a long-distance interference detection threshold 812, respectively, and calculate distance information.

[0220] The communication circuits 231 of the sonars 22a, 22c, and 22b transmit the distance information to the sensor control device 70. The sensor control device 70 receives the distance information via the I / F 11D, and the second detection unit 704 detects the presence or absence of an obstacle based on the distance information (process 7043).

[0221] Note that from process 7043 onwards, the same processes as processes 7022 to 7043 are executed. After receiving the reflected wave of the third ultrasonic wave transmitted by the sonar 22d, the second detection unit 704 detects whether or not there is an obstacle, and determines the detection result of whether or not there is an obstacle.

[0222] When the second detection unit 704 determines that an obstacle has been detected, it transmits information that an obstacle has been detected to the vehicle control device 50, etc. via the I / F 11D. This enables the vehicle control device 50 to issue a warning to the driver that an obstacle has been detected.

[0223] Next, the flow of processing executed by the sensor control device 70 according to this embodiment will be described.

[0224] The process executed by the sensor control device 70 will be described with reference to FIG.

[0225] First, the first detection unit 701 detects backward movement of the vehicle 1 (step S1). Specifically, the first detection unit 701 detects backward movement of the vehicle 1 by detecting +B output from the battery when the driver of the vehicle 1 performs an operation to put the gear into reverse.

[0226] Next, the sonar control unit 702 generates a sonar control signal (step S2). In this embodiment, the sonar control unit 702 generates a sonar control signal that causes the sonar 22 to transmit ultrasonic waves using frequency modulation A, which is a predetermined frequency modulation pattern, and a predetermined normal delay time.

[0227] Next, the sonar control unit 702 transmits the generated sonar control signal to the sonar 22a (step S3). Specifically, the sonar control unit 702 transmits the sonar control signal to the sonar 22a via the I / F 11D.

[0228] Here, the sonar control signal generated by the sonar control unit 702 is received by the communication circuit 231 of the sonar 22a. Then, in accordance with the received sonar control signal, the sonar 22a transmits ultrasonic waves with frequency modulation A and a normal delay time.

[0229] The ultrasonic waves transmitted by the sonar 22a are received by the sonar 22a, the sonar 22c, and the sonar 22b. The determination circuits 235 of the sonar 22a, the sonar 22c, and the sonar 22b calculate distance information. The calculated distance information is transmitted to the sensor control device 70 via the communication circuit 231.

[0230] Next, the acquisition unit 703 acquires distance information from the sonar 22a (step S4). Specifically, the acquisition unit 703 acquires distance information received from the sonar 22a via I / F 11D. Similarly, the acquisition unit 703 also acquires distance information from the sonar 22c (step S5). Similarly, the acquisition unit 703 also acquires distance information from the sonar 22b (step S6).

[0231] Next, the second detection unit 704 detects the presence or absence of an obstacle based on the distance information calculated by the sonar 22a, sonar 22c, and sonar 22b (step S7). Specifically, if the distance value A1 is calculated by all of the sonar 22a, sonar 22c, and sonar 22b, the second detection unit 704 detects that an obstacle is present. On the other hand, in other cases, the second detection unit 704 detects that no obstacle is present.

[0232] If an obstacle is detected (step S7: Yes), the sonar control unit 702 generates a sonar control signal that causes the sonar 22 to transmit ultrasonic waves with frequency modulation A and a normal delay time (step S8). Next, the sonar control unit 702 transmits the generated sonar control signal to the sonar 22b (step S9).

[0233] Then, in accordance with the received sonar control signal, the sonar 22b transmits ultrasonic waves with frequency modulation A and a normal delay time. The subsequent processing of the sonar 22 is the same as the processing after step S3, and therefore a description thereof will be omitted.

[0234] Next, the acquisition unit 703 acquires distance information from the sonar 22b (step S10). a The acquisition unit 703 acquires distance information from the sonar 22 (step S11). d Then, the process proceeds to step S18 (step S12).

[0235] On the other hand, if no obstacle is detected in step S7 (step S7: No), the sonar control unit 702 generates a sonar control signal that causes the sonar 22 to transmit ultrasonic waves with frequency modulation B and a normal delay time (step S13). Next, the sonar control unit 702 transmits the generated sonar control signal to the sonar 22b (step S14).

[0236] Then, in accordance with the received sonar control signal, the sonar 22b transmits ultrasonic waves with frequency modulation B and a normal delay time. The subsequent processing of the sonar 22 is the same as the processing after step S3, and therefore a description thereof will be omitted.

[0237] Next, the acquisition unit 703 acquires distance information from the sonar 22b (step S15). a The acquisition unit 703 acquires distance information from the sonar 22 (step S16). dObtain distance information and proceed to the process of step S18 (step S17).

[0238] After the process of step S12 or step S17, the second detection unit 704 detects an interference pattern based on the distance information calculated by the sonars 22a, 22c, and 22b (step S18).

[0239] Specifically, the second detection unit 704 compares the respective distance values of A1, A1K, and A1E obtained as distance information in steps S4 to S6 with the respective distance values of A2 (or B2), A2K (or B2K), and A2E (or B2E) calculated as distance information in steps S7 to S9 or steps S15 to S17, and detects an interference pattern.

[0240] Next, based on the interference pattern detected by the second detection unit 704, the sonar control unit 702 determines the frequency modulation pattern of the ultrasonic wave to be transmitted next time as frequency modulation A or frequency modulation B (step S19).

[0241] When it is determined as frequency modulation A (step S19: frequency modulation A), the sonar control unit 702 determines the transmission delay time of the ultrasonic wave to be transmitted next time without delay, generates a sonar control signal according to the determination, and then transmits the generated sonar control signal to the sonar 22a (step S21).

[0242] Then, the sonar 22a transmits an ultrasonic wave with frequency modulation A and no delay time according to the received sonar control signal. The subsequent processing of the sonar 22 is the same as the processing after step S3, so the description is omitted.

[0243] Next, the acquisition unit 703 acquires distance information from the sonar 22a (step S22). Also, the acquisition unit 703 acquires distance information from the sonar 22c (step S23). Further, the acquisition unit 703 acquires distance information from the sonar 22b and proceeds to the process of step S30 (step S24).

[0244] On the other hand, if frequency modulation B is selected in step S19 (step S19: frequency modulation B), the sonar control unit 702 determines that the delay time of the next ultrasonic wave transmission will be longer than the normal delay time, and generates a sonar control signal in accordance with the determination (step S25). Next, the sonar control unit 702 transmits the generated sonar control signal to the sonar 22a (step S26).

[0245] Then, in accordance with the received sonar control signal, the sonar 22a transmits ultrasonic waves with frequency modulation B and a longer delay time. The subsequent processing of the sonar 22 is similar to the processing after step S3, and therefore a description thereof will be omitted.

[0246] Next, the acquisition unit 703 acquires distance information from the sonar 22a (step S27). The acquisition unit 703 also acquires distance information from the sonar 22c (step S28). The acquisition unit 703 then acquires distance information from the sonar 22b, and proceeds to the processing of step S30 (step S29).

[0247] After the process of step S24 or step S29, the second detection unit 704 checks whether the next obstacle detection is the third time (step S30). If the next obstacle detection is the first or second time (step S30: No), the process proceeds to step S7.

[0248] On the other hand, if the detection of the presence or absence of an obstacle is the third time (step S30: Yes), the second detection unit 704 determines the detection result of the presence or absence of an obstacle based on the distance information calculated by the sonar 22a, sonar 22c, and sonar 22b, and ends this process (step S31). Note that the specific detection process is the same as step S7, so its description will be omitted.

[0249] As described above, in accordance with the detection of the start of the vehicle's reverse, the sensor control device 70 according to the present embodiment generates a control signal for controlling the sonar 22, and causes the sonar 22 to transmit the first ultrasonic wave at a predetermined frequency modulation pattern and transmission timing. Further, the sensor control device 70 acquires distance information calculated based on the received signal received after the first ultrasonic wave transmission from the sonar 22, detects the presence or absence of an obstacle based on the distance information, and determines the frequency modulation pattern of the second ultrasonic wave based on the detection result. At this time, when there is an obstacle, the sensor control device 70 determines the frequency modulation pattern as frequency modulation A, and when there is no obstacle, determines the frequency modulation pattern as frequency modulation B. The sensor control device 70 generates a control signal for controlling the sonar 22 based on the determined frequency modulation pattern, and causes the sonar 22 to transmit the second ultrasonic wave at the determined frequency modulation pattern and predetermined transmission timing. Further, the sensor control device 70 acquires distance information calculated based on the received signal received after the second ultrasonic wave transmission from the sonar 22, detects an interference pattern including the presence or absence of an obstacle based on the distance information, and determines the frequency modulation pattern and transmission timing of the third ultrasonic wave based on the detection result. At this time, the sensor control device 70 determines the frequency modulation pattern in the same manner as the second time. Further, when the distance to the interference position is approaching, the sensor control device 70 delays the transmission timing, and when the distance to the interference position is increasing, the sensor control device 70 advances the transmission timing. The sensor control device 70 generates a control signal for controlling the sonar 22 based on the determined frequency modulation pattern and transmission timing, and causes the sonar 22 to transmit the third ultrasonic wave at the determined frequency modulation pattern and transmission timing. Further, the sensor control device 70 acquires distance information calculated based on the received signal received after the third ultrasonic wave transmission from the sonar 22, and determines the presence or absence of an obstacle based on the distance information.

[0250] As a result, due to the interference pattern of the vehicle 1, the frequency modulation pattern and the transmission timing to be transmitted can be changed, so that interference from other vehicles and interference due to multiple reflections can be prevented. For example, by detecting the change in the interference position, when the interference position approaches the vehicle 1 over time, the transmission timing can be delayed, or when the interference position moves away from the vehicle 1 over time, the transmission timing can be advanced. In this way, even when other vehicles emit ultrasonic waves of the same frequency by shifting the transmission timing, interference can be made less likely to occur. For example, according to the sensor control device 70 according to the present embodiment, the possibility of misdetection of an obstacle due to an interference wave can be reduced.

[0251] Further, the sensor control device 70 detects the presence or absence of an obstacle, the presence or absence of short-distance interference, and the presence or absence of long-distance interference as the interference pattern. Therefore, the sensor control device 70 can determine the transmission timing according to various interference situations, such as whether an obstacle is detected around the vehicle 1, whether interference occurs near the vehicle 1, whether interference occurs at a far position, or whether interference occurs at both short and long distances. For example, according to the sensor control device 70 according to the present embodiment, the possibility of misdetection of an obstacle due to an interference wave can be reduced.

[0252] Further, the sensor control device 70 detects whether the obstacle is approaching the vehicle, whether the interference position of the short-distance interference is approaching the vehicle 1, and whether the interference position of the long-distance interference is approaching the vehicle 1 based on the temporal changes in the distance value between the vehicle 1 and the obstacle, the distance value between the vehicle 1 and the interference position of the short-distance interference, and the distance value between the vehicle 1 and the interference position of the long-distance interference. Thereby, the sensor control device 70 can determine the transmission timing of the ultrasonic wave according to whether the interference position is approaching or moving away. For example, according to the sensor control device 70 according to the present embodiment, the possibility of misdetection of an obstacle due to an interference wave can be reduced.

[0253] Note that the above-described embodiments can be appropriately modified and implemented by changing part of the configuration or function of each device of the vehicle 1. Therefore, below, some modification examples according to the above-described embodiments will be described as other embodiments. Note that below, the points different from the above-described embodiments will be mainly described, and detailed descriptions of the points common to the already described content will be omitted. Further, the modification examples described below may be implemented individually or in appropriate combinations.

[0254] (Modification Example 1) In the above-described embodiment, the form in which the sensor control device 70 has the functions of the first detection unit 701, the sonar control unit 702, the acquisition unit 703, and the second detection unit 704 has been described. However, part or all of these functions may be possessed by the controller 23 of the sonar 21 or the sonar 22.

[0255] In this modification example, the sonar control unit 702 generates a drive signal for controlling the drive circuit 241. The drive circuit 241 applies a voltage to the piezoelectric element 25 according to the drive signal generated by the sonar control unit 702. As a result, the sonar 21 or the sonar 22 can transmit ultrasonic waves at the frequency modulation pattern and transmission timing determined by the sonar control unit 702. Further, the acquisition unit 703 acquires the distance information calculated by the determination circuit 235.

[0256] According to this modification example, the processing load of the sensor control device 70 can be reduced.

[0257] (Modification Example 2) In the above-described embodiment, the transmission and reception of ultrasonic waves by the sonar 22a and the sonar 22c, and the transmission and reception of ultrasonic waves by the sonar 22b and the sonar 22d are regarded as one set of processing (one-time processing), and the processing is repeated three times, and after the third processing, the obstacle detection processing is performed, and the detection result is determined as the detection result of the presence or absence of an obstacle. However, the processing for determining the detection result of the presence or absence of an obstacle is not limited to this.

[0258] For example, after the transmission waves of the second sonars 22a and 22c, the detection process of obstacles may be performed, and the detection result may be determined as the detection result of the presence or absence of obstacles. Also, for example, three processes may be regarded as one set of processes, and the one set of processes may be repeated twice. After the second set of processes, the detection process of obstacles may be performed, and the detection result may be determined as the detection result of the presence or absence of obstacles.

[0259] The arrow LG1 in FIG. 32 represents a process of repeating the transmission and reception of ultrasonic waves by the sonar module twice as one set of processes (one process). After the transmission and reception of ultrasonic waves by the sonar module after the first process, the detection process of obstacles is performed, and the process of determining the presence or absence of obstacles is represented.

[0260] Also, the arrow LG2 represents a process of repeating the process of the arrow LG1 twice and determining the presence or absence of obstacles. Also, the arrow LG3 represents a process of repeating the process of the arrow LG2 twice and determining the presence or absence of obstacles.

[0261] Note that the user may be able to select any one of the processes of the arrow LG1, the arrow LG2, and the arrow LG3. Thereby, when the user wants to reduce the processing load of the sensor control device 70, the process of the arrow LG1 can be selected, and when the user wants to detect obstacles more accurately, the process of the arrow LG3 can be selected, etc., and processing according to the user's needs can be performed.

[0262] (Modification Example 3) In the above-described embodiment, the form of performing the detection process of the interference pattern and the determination process of the transmission condition of the ultrasonic wave to be transmitted next using the data tables shown in FIGS. 17 and 18 has been described. However, the above processing is not limited to this. For example, the sonar control unit 702 and the second detection unit 704 may perform the above processing using a data table defined by a logic different from the data tables shown in FIGS. 17 and 18.

[0263] FIG. 33 is an excerpt showing a portion of the interference pattern when the distance value of A1 is not measured in the data table according to Modification Example 3.

[0264] As shown in FIG. 33, in this data table, when the distance value of A1 is not measured by the first transmission of ultrasonic waves by the sonars 22a and 22c, it is determined that the frequency modulation pattern of the ultrasonic waves transmitted by the sonars 22a and 22c will be frequency modulation B next time.

[0265] FIG. 34 is an excerpt of a portion showing an interference pattern when the distance value of A1 is not measured in a data table according to a third modification different from FIG. 33.

[0266] When using the data table of FIG. 34 for the interference pattern detection process, the second detection unit 704 compares the distance value of A1K with the distance value of B2 when the distance value of B2K is not measured and the distance values of AIK and B2 are measured, and detects the interference pattern. Further, the sonar control unit 702 determines the transmission condition, giving priority to the comparison result between the distance value of A1K and the distance value of B2 over the comparison result between the distance value of A1E and the distance value of B2E.

[0267] Also, the distance value of A1K > the distance value of B2 indicates that another vehicle is approaching vehicle 1, and the distance value of A1K ≤ the distance value of B2 indicates that another vehicle is moving away from vehicle 1. In this case, the possibility of interference can be reduced by advancing the transmission timing of the ultrasonic waves. Therefore, in the data table of FIG. 34, when the distance value of A1K > B2, the transmission timing of the ultrasonic waves is set to be advanced.

[0268] FIG. 35 is an excerpt of a portion showing an interference pattern when the distance value of A1 is not measured in a data table according to a third modification different from FIGS. 33 and 34.

[0269] When using the data table of FIG. 35 for the interference pattern detection process, if the distance value of B2K is not measured and the distance values of AIK and B2 are measured, the second detection unit 704 compares the distance value of A1K with the distance value of B2 to detect the interference pattern. Also, the sonar control unit 702 determines the transmission condition by prioritizing the comparison result of the distance value of A1K and the distance value of B2 over the comparison result of the distance value of A1E and the distance value of B2E.

[0270] In the data table of FIG. 35, similar to the data table of FIG. 34, when the distance value of A1K > B2, the ultrasonic wave transmission timing is set to be advanced. Also, in the data table of FIG. 35, for interference patterns other than the case where the distance value of A1K > B2, the transmission conditions are determined based on substantially the same criteria as the data table of FIG. 18.

[0271] According to the configuration of the above-described embodiment, the possibility of erroneously detecting an obstacle due to an interference wave can be reduced.

[0272] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof.

[0273] Also, the notation “... unit” in the above-described embodiments may be replaced with other notations such as “... circuitry”, “... assembly”, “... device”, “... unit”, or “... module”.

[0274] In each of the above embodiments, the present disclosure has been described by way of an example configured using hardware, but the present disclosure can also be realized by software in cooperation with hardware.

[0275] Also, each functional block used in the description of each of the above embodiments is typically realized as an LSI, which is an integrated circuit. The integrated circuit may control each functional block used in the description of the above embodiment and include an input terminal and an output terminal. These may be individually formed into one chip, or may be formed into one chip so as to include part or all of them. Here, an LSI is mentioned, but depending on the degree of integration, it may also be referred to as an IC, a system LSI, a super LSI, or an ultra LSI.

[0276] Also, the method of integrating into an integrated circuit is not limited to LSI, and it may be realized using an application-specific circuit or a general-purpose processor and memory. After manufacturing the LSI, an FPGA (Field Programmable Gate Array) that can be programmed, or a reconfigurable processor that can reconfigure the connection or setting of circuit cells inside the LSI may be used.

[0277] Furthermore, if a technology for integrating into an integrated circuit that replaces the LSI appears due to the progress of semiconductor technology or other derived technologies, naturally, the functional blocks may be integrated using that technology. The application of biotechnology or the like is a possibility.

Explanation of Reference Numerals

[0278] 1 Vehicle 21a First front center sonar 21b Second front center sonar 21c First front corner sonar 21d Second front corner sonar 22a First rear center sonar 22b Second rear center sonar 22c First rear corner sonar 22d Second rear corner sonar 30 Steering control device 40 Speed control device 50 Vehicle control device 60 HMI device 70 Sensor control device 100 Vehicle-mounted system 701 First detection unit 702 Sonar control unit 703 Acquisition unit 704 Second detection unit

Claims

1. A transmission circuit that transmits a carrier signal subjected to frequency modulation, A receiving circuit that receives a signal from the outside, An object detection circuit that detects an object existing in the transmission direction of the carrier signal based on the reflected wave of the carrier signal received by the receiving circuit, An interference detection circuit that detects, as interference, another carrier signal transmitted from another transmission circuit different from the transmission circuit based on the signal received by the receiving circuit, A determination circuit that determines a frequency modulation pattern applied to the carrier signal and a transmission timing of the carrier signal based on detection results of the object detection circuit and the interference detection circuit, An obstacle detection device comprising the same.

2. When the object is detected, the determination circuit determines the frequency modulation pattern as a first pattern, and when the object is not detected, the determination circuit determines the frequency modulation pattern as a second pattern different from the first pattern. The obstacle detection device according to claim 1.

3. The transmission circuit repeatedly transmits the transmission of the carrier signal, The object detection circuit detects a change in the distance from the transmission circuit to the object based on the reflected wave repeatedly received by the receiving circuit. The obstacle detection device according to claim 1.

4. The interference detection circuit detects a change in the interference position representing the position from the transmission circuit to the interference based on the signal repeatedly received by the receiving circuit. The obstacle detection device according to claim 3.

5. When it is detected that the interference position is approaching the transmission circuit, the determination circuit delays the transmission timing, and when it is detected that the interference position is moving away from the transmission circuit, the determination circuit advances the transmission timing. The obstacle detection device according to claim 4.

6. The object detection circuit detects the object based on a change amount of the signal intensity of the reflected wave and a first threshold value representing the change amount of the signal intensity of the reflected wave for detecting the object. The obstacle detection device according to any one of claims 1 to 5.

7. The interference detection circuit detects a short-distance interference representing the interference occurring near the transmission circuit and a long-distance interference representing the interference occurring far from the transmission circuit. The obstacle detection device according to claim 6.

8. The interference detection circuit detects the short-distance interference based on a change amount of the signal intensity of the signal and a second threshold value representing the change amount of the signal intensity of the signal for detecting the short-distance interference. Detecting the long-distance interference based on the amount of change in the signal strength of the signal and a third threshold value representing the amount of change in the signal strength of the signal for detecting the long-distance interference The obstacle detection device according to claim 7

9. The second threshold value is a value larger than the first threshold value, and the third threshold value is a value smaller than the first threshold value The obstacle detection device according to claim 8

10. An obstacle detection method by an obstacle detection device including a transmission circuit that transmits a carrier signal subjected to frequency modulation and a reception circuit that receives a signal from the outside, comprising: Detecting an object existing in the transmission direction of the carrier signal based on a reflected wave of the carrier signal received by the reception circuit Detecting, as interference, another carrier signal transmitted from another transmission circuit different from the transmission circuit based on the signal received by the reception circuit Determining a frequency modulation pattern applied to the carrier signal and a transmission timing of the carrier signal based on the detection result of the object and the detection result of the interference Obstacle detection method

11. When the object is detected, determining the frequency modulation pattern as a first pattern, and when the object is not detected, determining the frequency modulation pattern as a second pattern different from the first pattern The obstacle detection method according to claim 10

12. The transmission of the carrier signal is repeatedly transmitted by the transmission circuit Detecting a change in the distance from the transmission circuit to the object based on the reflected wave repeatedly received by the reception circuit The obstacle detection method according to claim 10

13. Detecting a change in an interference position representing a position from the transmission circuit to the interference based on the signal repeatedly received by the reception circuit The obstacle detection method according to claim 12

14. When it is detected that the interference position is approaching the transmission circuit, delaying the transmission timing When it is detected that the interference position is moving away from the transmission circuit, advancing the transmission timing The obstacle detection method according to claim 13

15. Detecting the object based on the amount of change in the signal strength of the reflected wave and a first threshold value representing the amount of change in the signal strength of the reflected wave The obstacle detection method according to claim 10

16. Detecting a short-distance interference representing the interference occurring near the transmission circuit and a long-distance interference representing the interference occurring far from the transmission circuit The obstacle detection method according to claim 15 According to claim 17, detecting the short-distance interference based on the amount of change in the signal strength of the signal and a second threshold value representing the amount of change in the signal strength of the signal. Detecting the long-distance interference based on the amount of change in the signal strength of the signal and a third threshold value representing the amount of change in the signal strength of the signal, wherein the third threshold value is different from the second threshold value. The obstacle detection method according to claim 16. According to claim 18, the second threshold value is a value larger than the first threshold value, and the third threshold value is a value smaller than the first threshold value. The obstacle detection method according to claim 17.

19. A program for causing a computer of an obstacle detection device including a transmission circuit that transmits a carrier signal subjected to frequency modulation and a reception circuit that receives a signal from the outside to execute, Detecting an object existing in the transmission direction of the carrier signal based on the reflected wave of the carrier signal received by the reception circuit. Detecting, as interference, another carrier signal transmitted from another transmission circuit different from the transmission circuit based on the signal received by the reception circuit. Determining a frequency modulation pattern applied to the carrier signal and a transmission timing of the carrier signal based on the detection result of the object and the detection result of the interference. Program.

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