Object detection device and method for detecting object

Abstract

To provide an object detection device and an object detection method that can suppress deterioration of object detection performance.SOLUTION: One aspect of the object detection device of the present disclosure includes: a first sensor provided in a vehicle, for performing ultrasonic distance measurement for detecting an object; a second sensor provided in the vehicle, for performing the ultrasonic distance measurement for detecting the object after monitoring noise after the distance measurement of the first sensor; and a control unit for causing the second sensor to monitor the noise after a predetermined waiting time following the next distance measurement of the first sensor, in a case where the noise is detected.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to an object detection device and an object detection method. [Background technology]

[0002] 2. Description of the Related Art There is known an object detection device that uses a distance measurement sensor such as an ultrasonic sensor mounted on a vehicle to detect objects present around the vehicle.

[0003] The object detection device detects the presence or absence of an object around a vehicle by having a distance measurement sensor monitor noise for a predetermined period of time and then transmit ultrasonic waves. For example, if the distance measurement sensor does not detect noise during noise monitoring, the object detection device detects the position of the object from the time it takes for the distance measurement sensor to transmit ultrasonic waves and receive the reflected waves from the object. Furthermore, for example, if the distance measurement sensor does not detect noise during noise monitoring and does not receive the reflected waves from the object, the object detection device detects that no object is present around the vehicle. Furthermore, for example, if the distance measurement sensor detects noise during noise monitoring, the object detection device invalidates the detection result and skips object detection to prevent erroneous object detection due to interference with the noise.

[0004] Patent Document 1 discloses that when two ultrasonic sensors are used to detect an obstacle, if one of them detects noise, there is a possibility that interference with noise is occurring in the other one as well, so the detection results of both ultrasonic sensors are invalidated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6089585 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the above-mentioned existing technology, depending on the ultrasonic wave transmission cycle, the reflected wave of the previously transmitted ultrasonic wave may be erroneously detected as noise. In this case, the detection result is invalidated even though no noise was detected. Therefore, if such erroneous detection occurs frequently, the frequency of object detection may decrease, which may lead to a deterioration in object detection performance.

[0007] The present disclosure has been made in consideration of the above circumstances, and contributes to providing an object detection device and an object detection method that can suppress deterioration of object detection performance. [Means for solving the problem]

[0008] One aspect of the object detection device disclosed herein comprises a first sensor mounted on a vehicle that performs ultrasonic ranging to detect an object; a second sensor mounted on the vehicle that monitors noise after ranging by the first sensor and then performs ultrasonic ranging to detect the object; and a control unit that, when the noise is detected, causes the second sensor to wait a predetermined time after the next ranging by the first sensor before monitoring the noise.

[0009] One aspect of the object detection device disclosed herein comprises a first sensor mounted on a vehicle that performs ultrasonic ranging to detect an object; a second sensor mounted on the vehicle that monitors noise after ranging by the first sensor and then performs ultrasonic ranging to detect the object; and a control unit that, if the noise is detected, changes the first threshold value to a second threshold value greater than the first threshold value after the next ranging by the first sensor, and monitors the noise.

[0010] In one aspect of the object detection method disclosed herein, a control unit causes a first sensor installed in a vehicle to perform ultrasonic ranging to detect an object, and after the first sensor has performed ranging, causes a second sensor installed in the vehicle to monitor noise before performing the ultrasonic ranging to detect the object, and if the noise is detected, after the next ranging by the first sensor, causes the second sensor to wait a predetermined time before monitoring the noise before monitoring the noise.

[0011] In one aspect of the object detection method of the present disclosure, a control unit causes a first sensor installed in a vehicle to perform ultrasonic ranging to detect an object, and after the first sensor has performed ranging, causes a second sensor installed in the vehicle to monitor noise and then perform the ultrasonic ranging to detect the object, and if the noise is detected, after the next ranging by the first sensor, causes the second sensor to change the first threshold to a second threshold that is larger than the first threshold and monitor the noise. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide an object detection device and an object detection method that can suppress deterioration of object detection performance. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an example of a vehicle to which the object detection device of this embodiment is applied. [Figure 2] FIG. 2 is a block diagram showing an example of the functional configuration of the object detection device (vehicle) of this embodiment. [Figure 3] FIG. 3 is a block diagram showing an example of a detailed configuration of the distance measuring sensor of this embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the hardware configuration of the control device of this embodiment. [Figure 5] FIG. 5 is a diagram showing an example of control of the order of transmitting ultrasonic waves from the distance measuring sensor by the wave transmission control unit of this embodiment. [Figure 6]FIG. 6 is a diagram showing an example of the relationship between the wave transmission and wave reception of the distance measuring sensor when the wave transmission control shown in FIG. 5 is performed. [Figure 7] FIG. 7 is a diagram showing an example of control of the transmission timing of ultrasonic waves from the distance measuring sensor by the wave transmission control unit of this embodiment. [Figure 8] FIG. 8 is a diagram schematically illustrating an example of a situation in which the false detection of noise shown in FIG. 7 occurs. [Figure 9] FIG. 9 is a diagram showing the voltage value of the reflected wave received by the distance measuring sensor when the wave transmission control unit of this embodiment performs wait control on the distance measuring sensor. [Figure 10] FIG. 10 is a flowchart showing an example of the object detection process performed by the object detection device of this embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of control of the ultrasonic wave transmission timing and threshold value of the distance measuring sensor by the wave transmission control unit of the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present disclosure (hereinafter simply referred to as "the present embodiment") will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiment. Furthermore, the following embodiment and modified examples can be combined as appropriate.

[0015] First, the external configuration of a vehicle to which the object detection device of this embodiment is applied will be described.

[0016] FIG. 1 is a schematic diagram showing an example of a vehicle 1 to which an object detection device 100 of this embodiment is applied. As shown in FIG. 1, the vehicle 1 is equipped with a plurality of distance measurement sensors 10, a plurality of image capture devices 30, a plurality of radars 40, and a control device 90. The object detection device 100 detects objects present around the vehicle 1 using the distance measurement sensors 10, and is equipped with at least the distance measurement sensors 10 and the control device 90. In this embodiment, a case in which the object detection device 100 is applied to the vehicle 1 will be described as an example, but the present invention is not limited to this.

[0017] The distance measuring sensor 10 is provided on the vehicle 1 and is a sensor that detects objects present around the vehicle 1. In this embodiment, the distance measuring sensor 10 has a detection range of, for example, several centimeters to several meters, and detects the presence or absence of an object at a relatively short distance and the distance to the object. In this embodiment, the distance measuring sensor 10 is an ultrasonic sensor that performs ultrasonic distance measurement to detect an object, but is not limited to this. The ultrasonic sensor has a wave transmitting function that transmits ultrasonic waves of, for example, 20 kHz to 100 kHz as a transmission wave, and a wave receiving function that receives ultrasonic waves reflected by an object as a reflected wave.

[0018] In this embodiment, the vehicle 1 is equipped with distance measurement sensors 10, including distance measurement sensor 10RL, distance measurement sensor 10RLC, distance measurement sensor 10RRC, distance measurement sensor 10RR, distance measurement sensor 10FL, distance measurement sensor 10FLC, distance measurement sensor 10FRC, and distance measurement sensor 10FR. These distance measurement sensors 10 are provided at different positions on the vehicle 1. Furthermore, the detection ranges of the respective distance measurement sensors 10 are adjusted so that at least a portion of them do not overlap.

[0019] Distance measurement sensors 10RL, 10RLC, 10RRC, and 10RR are provided in the rear portion of vehicle 1. Distance measurement sensor 10RL is provided in the left corner of the rear portion of vehicle 1. Distance measurement sensor 10RLC is provided near the left center of the rear portion of vehicle 1. Distance measurement sensor 10RRC is provided near the right center of the rear portion of vehicle 1. Distance measurement sensor 10RR is provided in the right corner of the rear portion of vehicle 1.

[0020] The detection range 20RL of the ranging sensor 10RL, the detection range 20RLC of the ranging sensor 10RLC, the detection range 20RRC of the ranging sensor 10RRC, and the detection range 20RR of the ranging sensor 10RR are arranged so that they do not overlap at least partially. The detection ranges 20 of the multiple ranging sensors 10 in the rear section may be arranged so that they partially overlap.

[0021] Distance measurement sensor 10FL, distance measurement sensor 10FLC, distance measurement sensor 10FRC, and distance measurement sensor 10FR are provided in the front portion of vehicle 1. Distance measurement sensor 10FL is provided in the left corner of the front portion of vehicle 1. Distance measurement sensor 10FLC is provided near the left center of the front portion of vehicle 1. Distance measurement sensor 10FRC is provided near the right center of the front portion of vehicle 1. Distance measurement sensor 10FR is provided in the right corner of the front portion of vehicle 1.

[0022] The detection ranges of the distance measurement sensors 10FL, 10FLC, 10FRC, and 10FR are arranged so that they at least partially do not overlap, as in the rear section (not shown). The detection ranges of the distance measurement sensors 10 in the front section may also be arranged so that they partially overlap, as in the rear section.

[0023] The number and arrangement of the distance measurement sensors 10 provided on the vehicle 1 are not limited to the above. For example, one or more distance measurement sensors 10 may be provided on the side of the vehicle 1.

[0024] The image capturing device 30 captures an image of the surroundings of the vehicle 1 and outputs the captured image to the control device 90.

[0025] In this embodiment, the vehicle 1 is equipped with the imaging devices 30, namely, imaging device 30F and imaging device 30R. The imaging device 30F is provided at the front of the vehicle 1 and captures images of the area around the front of the vehicle 1. The imaging device 30R is provided at the rear of the vehicle 1 and captures images of the area around the rear of the vehicle 1. The number and arrangement of the imaging devices 30 provided on the vehicle 1 are not limited to the above embodiment. Furthermore, in the object detection device 100 of this embodiment, the imaging device 30 may be omitted.

[0026] The radar 40 detects an object around the vehicle 1 and measures the distance to the object (the distance between the object and the vehicle 1). The radar 40 detects an object around the vehicle 1 by scanning, for example, millimeter waves, which are electromagnetic waves.

[0027] In this embodiment, the vehicle 1 is equipped with radar 40F and radar 40R as radars 40. Radar 40F is provided in the front portion of the vehicle 1 and detects objects in the front vicinity of the vehicle 1 by scanning the front vicinity of the vehicle 1. Radar 40R is provided in the rear portion of the vehicle 1 and detects objects in the rear vicinity of the vehicle 1 by scanning the rear vicinity of the vehicle 1. Note that the number and arrangement of radars 40 provided in the vehicle 1 are not limited to the above-described embodiment. Furthermore, in the object detection device 100 of this embodiment, radar 40 may be omitted.

[0028] Next, the functional configuration of the object detection device (vehicle) of this embodiment will be described.

[0029] 2 is a block diagram showing an example of the functional configuration of the object detection device 100 (vehicle 1) of this embodiment. As shown in Fig. 2, the object detection device 100 (vehicle 1) includes a distance measurement sensor 10, an image capturing device 30, a radar 40, a G sensor 51, a steering angle sensor 53, a driving control unit 55, an operation unit 57, a meter computer 59, a storage unit 61, and a control device 90.

[0030] The distance measuring sensor 10, the image capturing device 30, the radar 40, the G sensor 51, the steering angle sensor 53, the driving control unit 55, the meter computer 59, the storage unit 61, and the control device 90 are communicatively connected via a bus 70. The bus 70 may be, for example, a local area network such as a CAN (Controller Area Network), but is not limited to this.

[0031] The distance measuring sensor 10 detects an object within its detection range and outputs the detection result of the object to the control device 90. Note that an object is something that can be detected by the distance measuring sensor 10. For example, an object may be an object that generates a reflected wave that reflects an ultrasonic wave transmitted from the distance measuring sensor 10.

[0032] Fig. 3 is a block diagram showing an example of a detailed configuration of the distance measuring sensor 10 of this embodiment. As shown in Fig. 3, the distance measuring sensor 10 includes a wave transmitting unit 12, a wave receiving unit 14, and a controller 16. The wave transmitting unit 12 and the wave receiving unit 14 are each connected to the controller 16 so as to be able to communicate with each other. Furthermore, the controller 16 is connected to a control device 90 so as to be able to communicate with each other.

[0033] The wave transmitting unit 12 transmits ultrasonic waves. The wave receiving unit 14 receives reflected waves that are generated when the ultrasonic waves hit an object and are reflected. The wave transmitting unit 12 and the wave receiving unit 14 transmit ultrasonic waves and receive reflected waves, for example, via piezoelectric elements or the like. Under instructions from the control device 90, the controller 16 controls the transmission timing, transmission period, and frequency of the ultrasonic waves transmitted from the wave transmitting unit 12. The controller 16 also controls the wave receiving unit 14 to monitor noise before causing the wave transmitting unit 12 to transmit ultrasonic waves. The controller 16 also measures the distance to the object (relative position with respect to the distance measuring sensor 10) by measuring the time from when the ultrasonic waves are transmitted by the wave transmitting unit 12 to when the reflected waves are received by the wave receiving unit 14. The controller 16 outputs detection results, including the noise monitoring results (presence or absence of noise), whether an object is detected, and the distance to the object, to the control device 90.

[0034] The imaging device 30 and the radar 40 have already been explained in FIG. 1, so explanations thereof will be omitted.

[0035] The G sensor 51 measures the speed and acceleration of the vehicle 1 and outputs the measurement results to the control device 90.

[0036] The steering angle sensor 53 detects the steering angle of the steering wheel provided on the vehicle 1 and outputs it to the control device 90 as steering angle information.

[0037] The driving control unit 55 is an ECU (Engine Control Unit) that controls the driving of the vehicle 1. The driving control unit 55 is communicably connected to an operation unit 57. The driving control unit 55 controls drive devices such as an engine and a motor of the vehicle 1, and controls transmission system devices such as a transmission of the vehicle 1, in accordance with operation information by the driver (passenger) received from the operation unit 57.

[0038] The operating unit 57 is operated by the driver. The operating unit 57 includes, for example, an ignition switch, a shift lever, an accelerator pedal, and a brake pedal. However, the operating unit 57 is not limited to these.

[0039] The driving control unit 55 controls the drive device and transmission system of the vehicle 1 according to operation information of the ignition switch, shift position information of the shift lever, accelerator pedal operation information of the accelerator pedal, and brake pedal information of the brake pedal.

[0040] The operation information of the ignition switch is, for example, information that indicates an instruction to supply power to each part of the electrical system of the vehicle 1 and an instruction to start the engine of the vehicle 1. Upon receiving the instruction to supply power to each part of the electrical system of the vehicle 1, the traveling control unit 55 starts supplying power to the electronic devices mounted on the vehicle 1. Furthermore, upon receiving the instruction to start the engine of the vehicle 1, the traveling control unit 55 starts the engine of the vehicle 1.

[0041] The shift lever shift position information is information that indicates the position of the shift lever, such as parking, reverse, neutral, or drive.

[0042] The meter computer 59 has an information notification function for passengers such as the driver. The information notification function includes, but is not limited to, a display function that displays information and a sound output function that outputs a sound representing the information. An example of the display function is a combination meter device that notifies by display. An example of the sound output function is an alarm sound generator that notifies by buzzer or voice.

[0043] The storage unit 61 stores various types of data. Examples of the storage unit 61 include, but are not limited to, at least one of a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, and an optical disk. The storage unit 61 may be composed of one or more storage media.

[0044] The control device 90 controls each part of the object detection device 100 (vehicle 1). In this embodiment, among the various controls performed by the control device 90, mainly ultrasonic wave transmission control for each of the multiple distance measuring sensors 10 and object detection processing using the detection results of the distance measuring sensors 10 will be described, but the control device 90 is not limited to these.

[0045] Fig. 4 is a block diagram showing an example of the hardware configuration of the control device 90 of this embodiment. As shown in Fig. 4, the control device 90 has a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 83, a RAM 85, an I / F 87, etc., which are interconnected via a bus 89, and has a hardware configuration that utilizes an existing computer.

[0046] The CPU 81 is a calculation device that controls the control device 90 of this embodiment. The ROM 83 stores programs and the like that realize various processes by the CPU 81. The RAM 85 stores data used for various processes by the CPU 81. The I / F 87 is an interface for sending and receiving data.

[0047] The programs for executing various controls and various processes executed by the control device 90 of this embodiment are provided by being pre-installed in the ROM 83, etc. The programs executed by the control device 90 of this embodiment may be provided by being recorded in a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD) in a format that can be installed or executed by the control device 90.

[0048] Returning to Figure 2, the description will continue. As shown in Figure 2, the control device 90 includes a wave transmission control unit 91, a detection result acquisition unit 93, an object detection unit 95, a determination unit 97, and a drive control unit 99. Some or all of the functional units included in the control device 90 may be realized, for example, by causing a processing device such as the CPU 81 to execute a program, for example, by software, or may be realized by hardware such as an IC (Integrated Circuit), or may be realized by a combination of software and hardware. Note that at least some of the functional units included in the control device 90 may be configured to be mounted on an external information processing device communicably connected to the control device 90 via a network or the like.

[0049] The wave transmission control unit 91 controls the transmission of ultrasonic waves from each of the multiple distance measurement sensors 10. In the following, wave transmission control of the distance measurement sensors 10 by the wave transmission control unit 91 of this embodiment will be described using distance measurement sensors 10RL, 10RLC, 10RRC, and 10RR provided in the rear portion of the vehicle 1 as an example. However, this is not limiting, and the method described below can also be applied to distance measurement sensors 10 provided in the front portion of the vehicle 1.

[0050] FIG. 5 is a diagram illustrating an example of control of the transmission order of ultrasonic waves from the distance measurement sensors 10 by the wave transmission control unit 91 of this embodiment. When ultrasonic waves are transmitted simultaneously from multiple distance measurement sensors 10, it may be difficult to distinguish which distance measurement sensor 10 transmitted the reflected ultrasonic wave, resulting in reduced distance measurement accuracy. Therefore, in this embodiment, the wave transmission control unit 91 sequentially transmits ultrasonic waves from each of the multiple distance measurement sensors 10 according to a predetermined wave transmission order. For example, as shown in FIG. 5, the control device 90 periodically causes each distance measurement sensor 10 to sequentially transmit ultrasonic waves in the following cycle: distance measurement sensors 10RL and 10RR, distance measurement sensor 10RLC, and distance measurement sensor 10RRC. Note that the distance measurement sensors 10RL and 10RR are provided at the corners of both ends of the vehicle 1, respectively, and thus are less susceptible to interference. Therefore, simultaneous transmission of ultrasonic waves is unlikely to result in reduced distance measurement accuracy. For this reason, in this embodiment, the wave transmission control unit 91 causes the distance measuring sensors 10RL and 10RR to transmit ultrasonic waves simultaneously.

[0051] Fig. 6 is a diagram showing an example of the relationship between wave transmission and wave reception of the distance measuring sensor 10 when performing the wave transmission control shown in Fig. 5. The example shown in Fig. 6 shows a scene in which the distance measuring sensor 10RLC transmits ultrasonic waves and the transmitted ultrasonic waves hit an object O and are reflected. In this scene, in addition to the distance measuring sensor 10RLC, the distance measuring sensors 10RL and 10RRC arranged adjacent to the distance measuring sensor 10RLC also receive the reflected waves. In this way, in this embodiment, the reflected waves are received not only by the distance measuring sensor 10 that transmitted the ultrasonic waves but also by distance measuring sensors 10 that are capable of receiving the reflected waves of the ultrasonic waves, thereby increasing the frequency of object detection and improving object detection performance.

[0052] Although not shown, for example, when ranging sensors 10RL and 10RR transmit ultrasonic waves, the reflected waves are received not only by ranging sensors 10RL and 10RR but also by adjacent ranging sensors 10RLC and 10RRC.Furthermore, for example, when ranging sensor 10RRC transmits ultrasonic waves, the reflected waves are received not only by ranging sensor 10RRC but also by adjacent ranging sensors 10RLC and 10RR.

[0053] Fig. 7 is a diagram showing an example of control of the timing of transmitting ultrasonic waves from the distance measuring sensor 10 by the wave transmission control unit 91 of this embodiment. In the example shown in Fig. 7, the wave transmission control unit 91 causes each distance measuring sensor 10 to transmit ultrasonic waves in the order of distance measuring sensors 10RL and 10RR, distance measuring sensor 10RLC, distance measuring sensor 10RRC, distance measuring sensors 10RL and 10RR, ... as described in Fig. 5.

[0054] In addition, in the example shown in Figure 7, the transmission control unit 91 sets the noise monitoring time performed before transmitting ultrasonic waves to NT for each ranging sensor 10, and sets the reception time to 25 ms for ranging sensors 10RL and 10RR, and 40 ms for ranging sensors 10RLC and 10RRC.

[0055] In the example shown in Fig. 7, it is assumed that the distance measuring sensors 10RL and 10RR are configured to detect an object located within approximately 3.5 m in the direction of travel (backward). Here, the time required to detect an object located 3.5 m ahead is approximately 20.6 ms according to formula (1). In the following, the speed of ultrasonic waves is assumed to be 340 m / s.

[0056] (3500mm / 340m / s)×2≒20.6ms…(1)

[0057] 7, it is assumed that the distance measuring sensors 10RLC and 10RRC are to detect an object located within approximately 6 m in the traveling direction (backward direction). Here, the time required to detect an object located 6 m ahead is approximately 35.3 ms according to formula (2).

[0058] (6000mm / 340m / s)×2≒35.3ms…(2)

[0059] As described above, the wave reception time for the distance measuring sensors 10RL and 10RR is calculated to be approximately 20.6 ms, and the wave reception time for the distance measuring sensors 10RLC and 10RRC is calculated to be approximately 35.3 ms. In contrast, in the example shown in FIG. 7, the wave reception time for the distance measuring sensors 10RL and 10RR is tightly set to 25 ms, and the wave reception time for the distance measuring sensors 10RLC and 10RRC is tightly set to 40 ms, thereby shortening the object detection cycle, increasing the detection frequency, and improving object detection performance. Also, in the example shown in FIG. 7, the distance measuring sensors 10RL and 10RR, which are provided in the corners of the rear of the vehicle 1, have a narrower detection range and shorter wave reception time than the distance measuring sensors 10RLC and 10RRC, thereby shortening the object detection cycle and increasing the detection frequency.

[0060] The noise monitoring time is the time during which each distance measuring sensor 10 monitors noise before transmitting ultrasonic waves to prevent interference between the transmitted ultrasonic waves and noise. A time NT common to all distance measuring sensors 10 is set as the noise monitoring time. The NT set as the noise monitoring time can be any time shorter than the 25 ms reception time of the distance measuring sensors 10RL and 10RR, for example. Examples of noise include, but are not limited to, noise from construction sites, strange noises from fluorescent lights, exhaust noise from motorcycles, and ultrasonic waves transmitted by oncoming vehicles.

[0061] As described above, the noise monitoring result is included in the detection result output by the distance measuring sensor 10 to the control device 90, and is therefore acquired by the detection result acquisition unit 93. If the noise monitoring result acquired by the detection result acquisition unit 93 indicates "noise present," the object detection unit 95 discards the detection result, invalidates whether or not an object is detected and the distance to the object, and skips object detection in order to prevent erroneous detection of an object due to interference with noise.

[0062] In this embodiment, as described above, the wave receiving time of the distance measuring sensor 10 is set tight in order to shorten the object detection cycle and increase the detection frequency. Therefore, when noise is monitored during the noise monitoring time, the reflected wave of the ultrasonic wave transmitted immediately before may be erroneously detected as noise.

[0063] In the example shown in Fig. 7, during noise monitoring time 201, distance measurement sensor 10RLC detects (falsely detects) the reflected wave of the ultrasonic wave transmitted by distance measurement sensor 10RL immediately before as noise. Fig. 8 is a diagram schematically illustrating an example of a situation in which the false detection of noise shown in Fig. 7 occurs. In the example shown in Fig. 8, vehicle 1 is traveling (backing up) in the traveling direction DT, and object 203 is located 5 m away from vehicle 1. In the state shown in Fig. 8, the reflected wave of the ultrasonic wave transmitted by distance measurement sensor 10RL hits object 203 and is reflected, and is detected as noise by distance measurement sensor 10RLC. Note that the time required to detect an object located 5 m ahead is approximately 29.4 ms according to equation (3).

[0064] (5000mm / 340m / s)×2≒29.4ms…(3)

[0065] If the wave reception time of the distance measuring sensor 10 is set too tight in this way, when an object is present at a distance slightly farther away than the distance to the detection target, the reflected ultrasonic waves from the object will return to the noise monitoring time of the distance measuring sensor 10 that next transmits ultrasonic waves, resulting in false detection. The distance to the detection target for the distance measuring sensor 10RL is, for example, 3.5 m. In this case, as described above, the detection result will be invalidated even though no noise was detected.

[0066] Furthermore, the state in which an object exists at a distance slightly farther away than the distance to the detection target is not resolved immediately but is considered to continue for a certain period of time. For example, the state shown in Fig. 8 will not be resolved unless the distance to the object 203 is reduced to about 3.5 m, which is the detection target distance of the distance measuring sensor 10RL, or the distance to the object 203 is increased enough that the reflected wave from the object 203 is not detected as noise. This leads to frequent situations in which the detection result is invalidated even though no noise is detected, which is undesirable.

[0067] Therefore, in this embodiment, when noise is detected by the ranging sensor 10RLC (an example of a second sensor), the transmission control unit 91 causes the ranging sensor 10RLC to wait a predetermined time before monitoring the noise after the next ranging measurement by the ranging sensor 10RL (an example of a first sensor), and then causes the ranging sensor 10RLC to monitor the noise.

[0068] Below, the timing of transmitting waves from each distance measuring sensor 10 shown in FIG. 7 will be explained, while the wait control for waiting for monitoring noise will be explained.

[0069] First, the wave transmission control unit 91 sets NT as the noise monitoring time and causes the distance measuring sensors 10RL and 10RR to monitor noise for NT. After the noise monitoring time has elapsed, the wave transmission control unit 91 sets 25 ms as the wave receiving time for the distance measuring sensors 10RL and 10RR and causes the distance measuring sensors 10RL and 10RR to transmit ultrasonic waves and detect the received reflected waves for 25 ms. After the wave receiving time has elapsed, the distance measuring sensors 10RL and 10RR output the detection results to the control device 90. Note that because the distance measuring sensors 10RL and 10RR have not detected noise, a description of the control performed by the control device 90 using the detection results will be omitted.

[0070] Next, the wave transmission control unit 91 sets NT as the noise monitoring time 201 and causes the ranging sensor 10RLC to monitor noise for NT (an example of a first time period). Here, as shown in FIG. 7, during the noise monitoring time 201, the ranging sensor 10RLC detects (falsely detects) the reflected wave of the ultrasonic wave transmitted by the ranging sensor 10RL immediately before as noise. After the noise monitoring time 201 has elapsed, the wave transmission control unit 91 sets 40 ms as the wave reception time of the ranging sensor 10RLC and causes the ranging sensor 10RLC to transmit ultrasonic waves and detect the received reflected wave for 40 ms. After the wave reception time has elapsed, the ranging sensor 10RLC outputs the detection result to the control device 90, and the detection result acquisition unit 93 acquires it.

[0071] In this case, since the noise monitoring result included in the detection result acquired by the detection result acquisition unit 93 indicates "noise present," the object detection unit 95 discards the detection result and invalidates whether an object is detected and the distance to the object. Also, since the noise monitoring result included in the detection result acquired by the detection result acquisition unit 93 indicates "noise present," the wave transmission control unit 91 sets a flag to set a wait time before the next noise monitoring by the distance measurement sensor 10RLC. For example, the wave transmission control unit 91 sets a flag indicating the distance measurement sensor 10RLC.

[0072] Next, the wave transmission control unit 91 checks whether the flag indicates the distance measurement sensor 10 to be next controlled. However, since the next control target is the distance measurement sensor 10RRC, normal control is performed. The wave transmission control unit 91 sets NT as the noise monitoring time and causes the distance measurement sensor 10RRC to monitor noise for NT. After the noise monitoring time has elapsed, the wave transmission control unit 91 sets 40 ms as the wave reception time of the distance measurement sensor 10RRC and causes the distance measurement sensor 10RRC to transmit ultrasonic waves and detect the received reflected waves for 40 ms. After the wave reception time has elapsed, the distance measurement sensor 10RRC outputs the detection result to the control device 90. Note that since the distance measurement sensor 10RRC has not detected noise, a description of the control performed by the control device 90 using the detection result will be omitted.

[0073] Next, the wave transmission control unit 91 checks whether the flag indicates the next distance measurement sensor 10 to be controlled. However, since the next distance measurement sensor 10 to be controlled is the distance measurement sensors 10RL and 10RR, normal control is performed. The wave transmission control unit 91 sets NT as the noise monitoring time and causes the distance measurement sensors 10RL and 10RR to monitor noise for NT. After the noise monitoring time has elapsed, the wave transmission control unit 91 sets 25 ms as the wave reception time for the distance measurement sensors 10RL and 10RR and causes the distance measurement sensors 10RL and 10RR to transmit ultrasonic waves and detect the received reflected waves for 25 ms. After the wave reception time has elapsed, the distance measurement sensors 10RL and 10RR output the detection results to the control device 90. Note that, since the distance measurement sensors 10RL and 10RR have not detected noise, a description of the control performed by the control device 90 using the detection results will be omitted.

[0074] Next, the wave transmission control unit 91 checks whether the flag indicates the distance measuring sensor 10 to be controlled next, and since the next control target is the distance measuring sensor 10RLC indicated by the flag, it initializes the flag and performs wait control. Fig. 9 is a diagram showing the voltage value of the reflected wave received by the distance measuring sensor 10RLC when the wave transmission control unit 91 of this embodiment performs wait control on the distance measuring sensor 10RLC.

[0075] The wave transmission control unit 91 sets NT as the WAIT time 211 and causes the ranging sensor 10RLC to wait for NT before monitoring noise. Here, as in the previous case, it is assumed that the situation in which the reflected waves of the ultrasonic waves transmitted by the ranging sensor 10RL are returned as noise has not been resolved. However, because the ranging sensor 10RLC does not monitor noise during the WAIT time 211, it does not detect the reflected waves 223 having a voltage value exceeding the threshold value 221 as noise, even if it receives them, as shown in FIG. 9.

[0076] Next, the wave transmission control unit 91 sets NT as the noise monitoring time 213 and causes the ranging sensor 10RLC to monitor noise for NT. As shown in FIG. 9, the ranging sensor 10RLC does not receive any reflected waves having a voltage value exceeding the threshold 221 during the noise monitoring time 213, and therefore does not detect noise. After the noise monitoring time 213 has elapsed, the wave transmission control unit 91 sets 40 ms as the wave reception time for the ranging sensor 10RLC and causes the ranging sensor 10RLC to transmit ultrasonic waves and detect the received reflected waves for 40 ms. As shown in FIG. 9, the ranging sensor 10RLC transmits ultrasonic waves 225 and receives reflected waves 227 having a voltage value exceeding the threshold 221 within the wave reception time. The reflected waves 227 are waves that are reflected when the ultrasonic waves 225 hit an object. After the wave reception time has elapsed, the ranging sensor 10RLC outputs the detection result to the control device 90. Since the distance measuring sensor 10RLC does not detect noise due to wait control, a description of the control performed by the control device 90 using the detection results will be omitted.

[0077] Returning to FIG. 2, the description of other functional units included in the control device 90 will continue.

[0078] The detection result acquisition unit 93 acquires the detection result output from the distance measurement sensor 10. As described above, the detection result includes the noise monitoring result (presence or absence of noise), presence or absence of object detection, and the distance to the object.

[0079] When the detection result acquired by the detection result acquisition unit 93 indicates "no noise" and "object present," the object detection unit 95 detects the relative position of the object from the distance to the object. Furthermore, when the detection result acquired by the detection result acquisition unit 93 indicates "no noise" and "no object," the object detection unit 95 detects that no object is present around the vehicle 1. Furthermore, when the detection result acquired by the detection result acquisition unit 93 indicates "noise present," the object detection unit 95 discards the detection result, invalidates whether or not an object was detected and the distance to the object, and skips object detection in order to prevent erroneous object detection due to interference with noise.

[0080] When the same object is detected a predetermined number of times by any of the distance measuring sensors 10, the determination unit 97 determines that the same object is an object present around the vehicle 1.

[0081] For example, suppose that the object detection unit 95 detects an object 5 m ahead of the previous detection result of the distance measurement sensor 10RLC, and detects an object 4.8 m ahead of the latest detection result of the distance measurement sensor 10RLC. In this case, the determination unit 97 compares the displacement of the object detected by the distance measurement sensor 10RLC with the movement amount due to the vehicle speed of the vehicle 1. If the two values ​​match, the determination unit 97 determines that tracking is successful and increments the reliability level. Thereafter, the determination unit 97 performs the above-described process each time the object detection unit 95 detects the position of an object from the detection result of the distance measurement sensor 10RLC. When the reliability level reaches an upper limit (e.g., 3), the determination unit 97 determines that the tracked object is present around the vehicle 1. Note that if the object detection unit 95 skips object detection due to "noise present," the determination unit 97 may also skip the determination process while maintaining the reliability level.

[0082] The drive control unit 99 controls the drive of the vehicle 1 based on the determination result of the determination unit 97. For example, the drive control unit 99 controls the traveling control unit 55 so as to avoid contact with the object determined by the determination unit 97. Also, for example, the drive control unit 99 controls the traveling control unit 55 so as to travel while avoiding contact with the object determined by the determination unit 97. Also, for example, the drive control unit 99 controls the traveling control unit 55 so as to stop while avoiding contact with the object determined by the determination unit 97.

[0083] Furthermore, the drive control unit 99 may output information about the object determined by the determination unit 97 to the meter computer 59. For example, the drive control unit 99 may cause the meter computer 59 to display or output by voice information indicating that the determined object is located around the vehicle 1.

[0084] FIG. 10 is a flowchart showing an example of the object detection process performed by the object detection device 100 of this embodiment.

[0085] First, the wave transmission control unit 91 checks whether or not a flag indicating the distance measuring sensor 10 to be next controlled is set (step S101).

[0086] If the flag indicating the distance measuring sensor 10 to be next controlled is set (Yes in step S101), the wave transmission control unit 91 sets NT as the WAIT time and causes the distance measuring sensor 10 to wait monitoring for noise for NT (step S103). On the other hand, if the flag indicating the distance measuring sensor 10 to be next controlled is not set (No in step S101), the process of step S103 is not performed.

[0087] Next, the wave transmission control unit 91 sets a noise monitoring time NT and causes the distance measuring sensor 10 to monitor noise for the period NT (step S105).

[0088] When the noise monitoring time has elapsed, the wave transmission control unit 91 sets the wave receiving time of the distance measuring sensor 10, causes the distance measuring sensor 10 to transmit ultrasonic waves (step S107), and causes the sensor 10 to detect the received reflected waves during the wave receiving time (step S109).

[0089] When the wave reception time has elapsed, the distance measuring sensor 10 outputs the detection result to the control device 90, and the detection result acquisition unit 93 acquires the detection result (step S111).

[0090] If the detection result indicates "noise is present" (Yes in step S113), the object detection unit 95 discards the detection result, invalidates whether an object was detected and the distance to the object, and skips object detection (step S115).

[0091] Next, the wave transmission control unit 91 sets a flag indicating the distance measuring sensor 10 that detected noise in order to set a wait time before the next noise monitoring for that distance measuring sensor 10 (step S117).

[0092] On the other hand, if the detection result indicates "no noise" and "object detection" (No in step S113, Yes in step S119), the determination unit 97 performs tracking processing of the object whose position is detected from the detection result of the distance measuring sensor 10 by the object detection unit 95 (step S121). On the other hand, if the detection result indicates "no object detection" (No in step S119), the processing of step S121 is not performed.

[0093] As described above, in this embodiment, when noise is detected by the distance measurement sensor 10RLC, the wave transmission control unit 91 causes the distance measurement sensor 10RLC to wait a predetermined time before monitoring noise after the next distance measurement by the distance measurement sensor 10RL, and then causes the distance measurement sensor 10RLC to monitor the noise. Therefore, if the noise is a reflected wave of an ultrasonic wave transmitted immediately before, the distance measurement sensor 10RLC receives the reflected wave during the waiting time, and therefore does not detect it as noise, preventing erroneous detection and preventing the detection result from being invalidated.

[0094] In this way, in this embodiment, if the noise is a reflected wave of the previously transmitted ultrasonic wave, it can be prevented from being erroneously detected as noise from the second time onwards. Therefore, according to this embodiment, it is possible to avoid a situation in which the detection result is invalidated even though no noise is detected, and it is possible to suppress deterioration of object detection performance.

[0095] Furthermore, according to this embodiment, the wait time is set to the same time as the noise monitoring time, so that simple control can prevent the reflected wave of the previously transmitted ultrasonic wave from being mistakenly detected as noise.

[0096] In this embodiment, the wave transmission control unit 91 makes the ranging sensor 10RLC wait for a predetermined time before monitoring the noise, so even if the noise is not a reflected wave of the ultrasonic wave transmitted previously but is noise such as a background noise, it can be correctly detected as noise, and erroneous detection of objects due to interference with noise can also be prevented.

[0097] (Variation 1) In the above embodiment, the WAIT time is set to a fixed time equal to the noise monitoring time, but the present invention is not limited to this. In Modification 1, an example will be described in which the WAIT time is variable within the range of the noise monitoring time.

[0098] When the ranging sensor 10 detects noise during the noise monitoring time, it identifies the noise detection time, which is the time required from the start of the noise monitoring time until the noise is detected, and includes this in the detection result. Furthermore, when the noise monitoring result included in the detection result indicates "noise present," the wave transmission control unit 91 sets a flag indicating the ranging sensor 10 that detected the noise and associates it with the noise detection time included in the detection result. When the next control target is the ranging sensor 10 indicated by the flag, the wave transmission control unit 91 sets the noise detection time as the WAIT time and causes the ranging sensor 10RLC to wait for the noise detection time before monitoring for noise.

[0099] In this way, in Modification 1, the WAIT time is a variable time until noise is actually detected, so compared to when the noise monitoring time is used for the WAIT time, the WAIT time can be shortened, shortening the object detection cycle and increasing the detection frequency. Note that the WAIT time may be set to a time that is equal to or greater than the noise detection time and equal to or less than the noise monitoring time.

[0100] The time when noise is detected may be, for example, the time when the voltage value exceeds a threshold value. For example, if noise is detected when three points, namely, the portion where the voltage value exceeds the threshold value, the peak of the voltage value, and the portion where the voltage value falls below the threshold value, are detected, the time when noise is detected may be the time when the peak of the voltage value occurs.

[0101] (Variation 2) In the above embodiment and modified example 1, an example was described in which a wait time was set to avoid detecting the reflected wave of the previously transmitted ultrasonic wave as noise, but this is not limited to this. In modified example 2, an example will be described in which a wait time is not set and the threshold value of the reflection intensity for noise monitoring is changed to avoid detecting the reflected wave of the previously transmitted ultrasonic wave as noise.

[0102] Fig. 11 is a diagram showing an example of control of the ultrasonic wave transmission timing and threshold value of the distance measuring sensor 10 by the wave transmission control unit 91 of Modification 2. Note that the ultrasonic wave transmission timing shown in Fig. 11 is the same as the ultrasonic wave transmission timing shown in Fig. 7 except that no WAIT time is provided, so here we will explain noise monitoring by the distance measuring sensor 10RLC.

[0103] First, we will explain the control during the noise monitoring time 201. The wave transmission control unit 91 sets NT as the noise monitoring time 201 and causes the distance measuring sensor 10RLC to monitor noise during NT (an example of a first time period). Here, as shown in Fig. 11, during the noise monitoring time 201, the distance measuring sensor 10RLC receives a reflected wave 233 of the ultrasonic wave transmitted immediately before by the distance measuring sensor 10RL, and since the voltage value of the reflected wave 233 exceeds the threshold value 221, it detects it as noise (falsely detected).

[0104] Next, we will explain the control during the noise monitoring time 213. The wave transmission control unit 91 checks whether the flag indicates the distance measuring sensor 10 to be next controlled, and since the next control target is the distance measuring sensor 10RLC indicated by the flag, it initializes the flag and performs threshold control.

[0105] As shown in FIG. 11 , the wave transmission control unit 91 causes the ranging sensor 10RLC to change the threshold value 221 to a threshold value 231 that is greater than the threshold value 221. The wave transmission control unit 91 also sets NT as the noise monitoring time 213 and causes the ranging sensor 10RLC to monitor noise for NT. Here, it is assumed that, as in the previous case, the state in which the reflected waves of the ultrasonic waves transmitted by the ranging sensor 10RL are returned as noise has not been resolved. The ranging sensor 10RLC receives the reflected wave 223 during the noise monitoring time 213, but since the threshold value 221 has been changed to the threshold value 231 and the reflected wave 223 does not have a voltage value that exceeds the threshold value 231, the ranging sensor 10RLC does not detect the reflected wave 223 as noise. When the noise monitoring time 213 has elapsed, the wave transmission control unit 91 causes the ranging sensor 10RLC to change the threshold value 231 back to the threshold value 221.

[0106] In this way, in variant example 2, threshold control is used without setting a WAIT time, thereby avoiding the reflected wave of the previously transmitted ultrasonic wave being detected as noise, and therefore the object detection cycle can be shortened and the detection frequency can be increased compared to when a WAIT time is set.

[0107] (Variation 3) The weight control of Modification 1 and the threshold control of Modification 2 may be combined. For example, if the reflected wave does not fall below the threshold even after performing threshold control, the transmission wave control unit 91 may perform weight control instead of threshold control from the next time onwards to avoid detecting the reflected wave of the previously transmitted ultrasonic wave as noise. Also, for example, if the reflected wave is monitored as noise during the noise monitoring time even after performing weight control, the transmission wave control unit 91 may perform threshold control instead of weight control from the next time onwards to avoid detecting the reflected wave of the previously transmitted ultrasonic wave as noise. Note that, instead of performing threshold control instead of weight control, threshold control may also be performed in addition to weight control.

[0108] (Variation 4) In the above embodiment, it has been explained on the assumption that the frequency at which ultrasonic waves are transmitted is the same for all distance measurement sensors 10, but this is not limitative and the frequency may be made different depending on the placement position of the distance measurement sensor 10. For example, the frequency may be made different for a distance measurement sensor 10 placed near the center of the vehicle 1 and a distance measurement sensor 10 placed near the side of the vehicle 1.

[0109] (program) The programs executed by the object detection devices of the above embodiments and each of the above variations are provided as files in an installable or executable format stored on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD).

[0110] The programs executed by the object detection devices of the above embodiments and each of the above modifications may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. The programs executed by the object detection devices of the above embodiments and each of the above modifications may be provided or distributed via a network such as the Internet. The programs executed by the object detection devices of the above embodiments and each of the above modifications may be provided by being pre-installed in a ROM or the like.

[0111] The programs executed by the object detection devices of the above-described embodiments and modifications have a modular structure for implementing the above-described units on a computer. In terms of actual hardware, for example, the CPU reads the learning program from the HDD onto the RAM and executes it, thereby implementing the above-described units on the computer.

[0112] As described above, according to the above embodiment and the above modifications, it is possible to suppress deterioration of object detection performance.

[0113] The above-described embodiment and each of the above-described modifications merely illustrate examples of specific embodiments of the present disclosure, and the technical scope of the present disclosure should not be construed as being limited by these. For example, the present disclosure can be implemented in various forms without departing from the gist or main features thereof. For example, the above-described embodiment and each of the above-described modifications may be appropriately combined in their respective constituent units. Furthermore, for example, some components may be deleted from all components in the above-described embodiment and each of the above-described modifications.

[0114] In the above description, the notation "... section" used for each component may be replaced with other notations such as "... assembly," "... circuit," "... device," "... unit," or "... module." The object detection device may also be configured to be executed by a CPU using a program stored in memory.

[0115] The present disclosure includes the following aspects.

[0116] (1) a first sensor provided on a vehicle and configured to perform ultrasonic ranging for detecting an object; a second sensor provided on the vehicle, which monitors noise after the first sensor measures distance, and then performs the ultrasonic distance measurement to detect the object; a control unit that, when the noise is detected, causes the second sensor to wait a predetermined time from monitoring the noise after the next distance measurement by the first sensor, and then causes the second sensor to monitor the noise; An object detection device comprising:

[0117] (2) the second sensor monitors the noise for a predetermined first time period; The predetermined time is the first time. The object detection device according to (1) above.

[0118] (3) The predetermined time is a time elapsed from when the second sensor starts monitoring the noise until the noise is detected. The object detection device according to (1) above.

[0119] (4) The device further includes a determination unit that determines, when the same object is detected a predetermined number of times by either the first sensor or the second sensor, that the same object is the object. The object detection device according to any one of (1) to (3) above.

[0120] (5) a first sensor provided on the vehicle, the first sensor performing ultrasonic distance measurement for detecting an object; a second sensor provided on the vehicle, which monitors noise after the first sensor measures distance, and then performs the ultrasonic distance measurement to detect the object; a control unit that, when the noise is detected, changes the first threshold value to a second threshold value that is greater than the first threshold value after the next distance measurement by the first sensor, and monitors the noise; An object detection device comprising:

[0121] (6) The control unit: a first sensor provided on the vehicle to perform ultrasonic ranging to detect an object; After the distance measurement by the first sensor, a second sensor provided on the vehicle is caused to monitor noise and then perform the ultrasonic distance measurement to detect the object; when the noise is detected, after the next distance measurement by the first sensor, making the second sensor wait for a predetermined time before monitoring the noise, and then making the second sensor monitor the noise. Object detection methods.

[0122] (7) causing the second sensor to monitor the noise for a first predetermined time period; The predetermined time is the first time. The object detection method according to (6) above.

[0123] (8) The predetermined time is a time elapsed from when the second sensor starts monitoring the noise until the noise is detected. The object detection method according to (6) above.

[0124] (9) The control unit When the same object is detected a predetermined number of times by either the first sensor or the second sensor, the same object is determined to be the object. The object detection method according to any one of (6) to (8) above.

[0125] (10) The control unit: a first sensor provided on the vehicle to perform ultrasonic ranging to detect an object; After the distance measurement by the first sensor, a second sensor provided on the vehicle is caused to monitor noise and then perform the ultrasonic distance measurement to detect the object; If the noise is detected, after the next distance measurement by the first sensor, the second sensor changes the first threshold value to a second threshold value that is greater than the first threshold value, and monitors the noise. Object detection methods. [Explanation of symbols]

[0126] 1 vehicle 10, 10RL, 10RLC, 10RRC, 10RR distance measuring sensors 12 Transmitting unit 14 Receiver section 16 Controllers 30 Imaging equipment 40 Radar 51 G sensor 53 Steering angle sensor 55 Travel control unit 57 Operation section 59 Meter Computer 61 Storage section 70 Bus 81 CPU 83 ROM 85 RAM 87 Interface 89 Bus 90 Control device 91 Transmission control section 93 Detection result acquisition unit 95 Object detection unit 97 Judgment section 99 Drive control unit 100 Object detection device

Claims

1. a first sensor provided on the vehicle and configured to perform ultrasonic distance measurement for detecting an object; a second sensor provided on the vehicle, which monitors noise after the first sensor measures distance and then performs ultrasonic distance measurement to detect the object; a control unit that, when the noise is detected, causes the second sensor to wait a predetermined time from monitoring the noise after the next distance measurement by the first sensor, and then causes the second sensor to monitor the noise; An object detection device comprising:

2. the second sensor monitors the noise for a first predetermined time period; the predetermined time is the first time, The object detection device according to claim 1 .

3. the predetermined time is a time elapsed from when the second sensor starts monitoring the noise until the noise is detected. The object detection device according to claim 1 .

4. a determination unit that determines, when the same object is detected a predetermined number of times by either the first sensor or the second sensor, that the same object is the object; The object detection device according to any one of claims 1 to 3.

5. a first sensor provided on the vehicle and configured to perform ultrasonic distance measurement for detecting an object; a second sensor provided on the vehicle, which monitors noise after the first sensor measures distance and then performs ultrasonic distance measurement to detect the object; a control unit that, when the noise is detected, changes the first threshold value to a second threshold value that is greater than the first threshold value after the next distance measurement by the first sensor, and monitors the noise; An object detection device comprising:

6. The control unit causing a first sensor provided on the vehicle to perform ultrasonic distance measurement to detect an object; After the distance measurement by the first sensor, a second sensor provided on the vehicle is caused to monitor noise and then to perform the ultrasonic distance measurement to detect the object; when the noise is detected, after the next distance measurement by the first sensor, the second sensor is made to wait for a predetermined time before monitoring the noise, and then the second sensor is made to monitor the noise. Object detection methods.

7. causing the second sensor to monitor the noise for a first predetermined time period; the predetermined time is the first time, The object detection method according to claim 6 .

8. the predetermined time is a time elapsed from when the second sensor starts monitoring the noise until the noise is detected. The object detection method according to claim 6 .

9. The control unit When the same object is detected a predetermined number of times by either the first sensor or the second sensor, the same object is determined to be the object. The object detection method according to any one of claims 6 to 8.

10. The control unit causing a first sensor provided on the vehicle to perform ultrasonic distance measurement to detect an object; After the distance measurement by the first sensor, a second sensor provided on the vehicle is caused to monitor noise and then to perform the ultrasonic distance measurement to detect the object; If the noise is detected, after the next distance measurement by the first sensor, the second sensor changes the first threshold value to a second threshold value that is greater than the first threshold value, and monitors the noise. Object detection methods.

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