JP2018169366A - Object detection device, object detection system, and mobile body - Google Patents

Abstract

To provide an object detection device, an object detection system, and a mobile body that can perform short distance object detection and long distance object detection while reducing difference between a frequency used for the short distance object detection and a frequency used for the long distance object detection.SOLUTION: An object detection device 10 includes a wave transmission control unit 13 and a detection unit 14. The wave transmission control unit 13 controls a wave transmission unit 21 to repeat transmitting ultrasonic waves from the wave transmission unit 21 while switching a plurality of wave transmission time lengths to transmit the ultrasonic waves. The detection unit 14 detects an object within a detection space (common space E3 and spaces E10 and E11) on the basis of a wave reception time from transmitting the ultrasonic waves to receiving reflection waves of the ultrasonic waves by a wave receiving unit 22.SELECTED DRAWING: Figure 1

Description

  The present invention generally relates to an object detection device, an object detection system, and a moving body, and more particularly relates to an object detection device, an object detection system, and a moving body that detect an object using ultrasonic waves.

  2. Description of the Related Art Conventionally, an obstacle detection device that detects an obstacle (object) using ultrasonic waves is known, and is disclosed in, for example, Patent Document 1. The obstacle detection apparatus described in Patent Document 1 changes the obstacle detection range by changing the frequency of ultrasonic waves to be transmitted. Thereby, it is possible to detect an obstacle at a short distance or an obstacle at a long distance.

JP 2009-14560 A

  In Patent Literature 1, short-distance object detection and long-distance object detection are performed by switching frequencies. Depending on the short-range object detection range and the long-range object detection range, the difference between the frequency used for short-range object detection and the frequency used for long-range object detection becomes large.

  Therefore, the present invention has been made in view of the above-mentioned reasons, and while reducing the difference between the frequency used for short-distance object detection and the frequency used for long-distance object detection, short-distance object detection and long-distance detection An object of the present invention is to provide an object detection device, an object detection system, and a moving body that can perform object detection.

  The object detection apparatus according to the first aspect of the present invention includes a transmission control unit and a detection unit. The wave transmission control unit controls the wave transmission unit to repeat the ultrasonic wave transmission from the wave transmission unit while switching a plurality of wave transmission time lengths for transmitting the ultrasonic wave. The detection unit detects an object in a detection area based on a reception time from when the ultrasonic wave is transmitted until the reception unit receives the reflected wave of the ultrasonic wave.

  In the object detection device according to the second aspect, in the first aspect, the detection unit is associated with the plurality of transmission time lengths and uses a plurality of thresholds with respect to the reception intensity of the ultrasonic waves. Detect objects.

  In the object detection apparatus according to the third aspect, in the second aspect, each of the plurality of threshold values changes with respect to the time axis direction until the object detection processing by the detection unit is completed.

  In the object detection device according to the fourth aspect, in the second or third aspect, the detection unit uses a threshold value according to the transmission time length switched by the transmission control unit among the plurality of threshold values. To detect the object.

  In the object detection device according to the fifth aspect, in any one of the first to fourth aspects, a plurality of the wave transmission units exist. There are a plurality of wave receiving sections, and each correspond to the plurality of wave transmitting sections. The transmission control unit controls the plurality of transmission units to repeat the ultrasonic transmission of each of the transmission units while switching the plurality of transmission time lengths. The detection unit detects an object in a detection area for each of the wave receiving units based on the wave receiving time for the ultrasonic wave transmitted by the corresponding wave transmitting unit.

  In the object detection device according to a sixth aspect, in the fifth aspect, the plurality of transmission time lengths are a first transmission time length and a second transmission time length shorter than the first transmission time length. including. The transmission control unit sequentially controls the plurality of transmission units such that each of the transmission units transmits the ultrasonic wave with the first transmission time length. The detection unit is configured such that each of the transmission units transmits the ultrasonic wave with the first transmission time length, and then the corresponding transmission unit transmits the ultrasonic wave with the first transmission time length. On the basis of the reception time for the object, detection of an object in a detection area is performed for each of the reception units. The detection unit, when the detection results in at least two reception units among the plurality of reception units indicate that an object has been detected, from the combination of detection results in the at least two reception units Find the position of the object. The transmission control unit sequentially controls the plurality of transmission units so that each of the transmission units transmits the ultrasonic wave with the second transmission time length. The detection unit is configured such that each of the transmission units transmits the ultrasonic wave with the first transmission time length, and then the corresponding transmission unit transmits the ultrasonic wave with the second transmission time length. On the basis of the reception time for the object, detection of an object in a detection area is performed for each of the reception units.

  In the object detection device according to the seventh aspect, in any one of the first to sixth aspects, the frequencies of the ultrasonic waves transmitted in the plurality of transmission time lengths are the same.

  An object detection system according to an eighth aspect includes the object detection device according to any one of the first to seventh aspects, the wave transmission unit, and the wave reception unit.

  The moving body according to the ninth aspect includes the object detection system according to the eighth aspect.

  According to the present invention, it is possible to perform short-distance object detection and long-distance object detection while reducing the difference between the frequency used for distance object detection and the frequency used for long-distance object detection.

FIG. 1 is a block diagram illustrating a configuration of an object detection system according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a vehicle in which the object detection system is used. FIG. 3A is a diagram schematically illustrating an ultrasonic waveform transmitted by the object detection system according to the first transmission time length. FIG. 3B is a diagram schematically illustrating the relationship between the waveform of the reflected wave of the ultrasonic wave transmitted by the object detection system according to the first transmission time length and the first threshold value. FIG. 3C is a diagram schematically illustrating a waveform of an ultrasonic wave transmitted by the object detection system according to the second transmission time length. FIG. 3D is a diagram schematically illustrating the relationship between the waveform of the reflected wave of the ultrasonic wave transmitted by the object detection system of the same as the second transmission time length and the second threshold value. FIG. 4 is a diagram for explaining the operation when the object detection system according to the embodiment transmits ultrasonic waves.

  Each embodiment and modification described below are only examples of the present invention, and the present invention is not limited to the embodiment and modification. Even if it is except this embodiment and a modification, if it is a range which does not deviate from the technical idea which concerns on this invention, a various change is possible according to a design etc.

(Embodiment)
The object detection apparatus 10 and the object detection system 100 in this embodiment are demonstrated using FIGS.

  The object detection system 100 of the present embodiment is mounted on a moving body 200 such as an automobile (see FIG. 2). Below, the mobile body 200 is demonstrated as a motor vehicle.

  The object detection system 100 of this embodiment detects the presence or absence of an object in a plurality of spaces as detection targets. For example, the object detection system 100 detects the presence or absence of an object in a space close to the moving body 200 (spaces E11 and E12 described later) and a space away from the moving body 200 (a common space E3 described later).

  The object detection system 100 has a driving support function (hereinafter referred to as a first function) and a peripheral object detection function (hereinafter referred to as a second function). The first function is a function of detecting the presence or absence of an object in the moving direction of the moving body 200 and controlling the speed of the moving body 200 or controlling the brake according to the detection result. The second function is a function of detecting the presence or absence of an object around the moving body 200.

  As shown in FIG. 1, the object detection system 100 includes an object detection device 10 and a plurality of ultrasonic sensors 20 (here, two ultrasonic sensors 20). In the present embodiment, when the two ultrasonic sensors 20 are distinguished, they are described as an ultrasonic sensor 20A and an ultrasonic sensor 20B.

  The ultrasonic sensor 20 is attached to the moving body 200 (for example, a rear bumper). Specifically, the ultrasonic sensor 20A is attached to a position closer to one end than the center of the rear bumper, and the ultrasonic sensor 20B is attached to a position closer to the other end than the center of the rear bumper (see FIG. 2).

  As shown in FIG. 1, the ultrasonic sensor 20 includes a wave transmission unit 21, a wave reception unit 22, and a drive unit 23.

  The wave transmission unit 21 is configured to convert an electric signal into mechanical vibration. In the present embodiment, the wave transmitting unit 21 vibrates by a predetermined electric signal output from the driving unit 23, and transmits (transmits) an ultrasonic wave toward the space by vibrating air. In the present embodiment, the wave transmission unit 21 transmits ultrasonic waves at regular intervals according to the electrical signal from the drive unit 23. That is, the wave transmission part 21 transmits an ultrasonic wave indirectly.

  The wave receiving unit 22 is configured to convert mechanical vibration into an electric signal. In the present embodiment, the wave receiving unit 22 receives a reflected wave reflected by an object from among the ultrasonic waves transmitted from the wave transmitting unit 21 of the ultrasonic sensor 20A and the wave transmitting unit 21 of the ultrasonic sensor 20B ( Receiving) and converting the received reflected wave into an electric signal. The wave receiving unit 22 outputs the converted electric signal to the object detection device 10.

  The drive unit 23 outputs an electrical signal based on the drive signal received from the object detection device 10 to the transmission unit 21 with a plurality of transmission time lengths under the control of the object detection device 10, and with a plurality of transmission time lengths. Send ultrasonic waves. Note that the frequencies of ultrasonic waves transmitted with a plurality of transmission time lengths are the same. Note that communication between the ultrasonic sensor 20 and the object detection apparatus 10 is performed by, for example, LIN (Local Interconnect Network) communication.

  The drive unit 23 includes a filter circuit that removes frequency components that deviate from the frequency of the transmitted ultrasonic waves. The drive unit 23 outputs the electrical signal filtered by the filter circuit to the wave transmission unit 21. Accordingly, the drive unit 23 can cause the wave transmission unit 21 to output an ultrasonic wave having an appropriate frequency.

  In this embodiment, the wave transmission part 21 and the wave reception part 22 are integrally comprised, for example with the ultrasonic transducer. The drive unit 23 is housed in a housing that houses the ultrasonic transducer. In addition, the wave transmission part 21, the wave receiving part 22, and the drive part 23 may each be comprised separately. For example, the housing in which the wave transmitting unit 21 and the wave receiving unit 22 are stored may be separated from the housing in which the driving unit 23 is stored. Or the housing | casing in which the wave transmission part 21 and the drive part 23 are accommodated, and the housing | casing in which the wave receiving part 22 is accommodated may be separated. In addition, the housing in which the wave transmission unit 21 is housed, the housing in which the wave receiving unit 22 is housed, and the housing in which the driving unit 23 is housed may be separated.

  As illustrated in FIG. 1, the object detection device 10 includes a processing unit 11 and a storage unit 12.

  The storage unit 12 includes a device selected from a ROM (Read Only Memory), a RAM (Random Access Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), or the like. The storage unit 12 stores data necessary for detecting an object using the electrical signal received by the wave receiving unit 22.

  The processing unit 11 is an ECU (Electronic Control Unit) and includes, for example, an MCU (Micro Control Unit) as a main configuration. The processing unit 11 (MCU) implements a function as the processing unit 11 by executing a program recorded in the memory by a CPU (Central Processing Unit).

  As illustrated in FIG. 1, the processing unit 11 includes a wave transmission control unit 13 and a detection unit 14.

  The transmission control unit 13 controls the transmission unit 21 to repeat the transmission of ultrasonic waves from the transmission unit 21 of the ultrasonic sensor 20 while switching a plurality of transmission time lengths.

  For example, the wave transmission control unit 13 controls the drive unit 23 of the ultrasonic sensor 20A so that the ultrasonic sensor 20A transmits an ultrasonic wave with the first transmission time length. Specifically, the transmission control unit 13 generates a drive signal having a predetermined frequency, and outputs the generated drive signal to the drive unit 23 of the ultrasonic sensor 20A with the first transmission time length. Thereby, the wave transmission unit 21 of the ultrasonic sensor 20 </ b> A can transmit ultrasonic waves with the first transmission time length. Thereafter, the transmission control unit 13 controls the drive unit 23 of the ultrasonic sensor 20B so that the ultrasonic sensor 20B transmits ultrasonic waves with the first transmission time length. Specifically, the transmission control unit 13 generates a drive signal having a predetermined frequency, and outputs the generated drive signal to the drive unit 23 of the ultrasonic sensor 20B with the first transmission time length. In each of the ultrasonic sensors 20A and 20B, after the ultrasonic wave is transmitted with the first transmission time length, the transmission control unit 13 performs the supersonic with the second transmission time length shorter than the first transmission time length. The ultrasonic sensor 20A is controlled so as to transmit a sound wave. Specifically, the drive unit 23 of the ultrasonic sensor 20A is controlled so that the ultrasonic sensor 20A transmits an ultrasonic wave with the second transmission time length. Specifically, the transmission control unit 13 generates a drive signal having a predetermined frequency, and outputs the generated drive signal to the drive unit 23 of the ultrasonic sensor 20A with the second transmission time length. Thereafter, the transmission control unit 13 controls the ultrasonic sensor 20B so as to transmit ultrasonic waves with the second transmission time length.

  The transmission control unit 13 sets the above-described operation as one cycle and repeats this cycle, so that each of the ultrasonic sensors 20A and 20B transmits ultrasonic waves with the first transmission time length and the second transmission time length. Control to do.

  The detecting unit 14 receives the waveform of the receiving unit 22 that receives the reflected wave of the ultrasonic wave transmitted for the first transmission time length and the reflected wave of the ultrasonic wave that is transmitted for the second transmission time length. Based on each of the waveforms of the wave receiving unit 22, the presence or absence of an object in the space to be detected by the ultrasonic sensor 20 is detected. The detection unit 14 also detects the distance to the detected object based on the time (wave reception time) from when the wave transmission unit 21 transmits ultrasonic waves until the wave reception unit 22 receives reflected waves. Ask for. Further, when an object is detected by both the ultrasonic sensors 20A and 20B with respect to the ultrasonic wave transmitted in the first transmission time length, the detection unit 14 triangulates the position of the detected object. Using a surveying method such as method.

  The detection part 14 outputs the detection result of the presence or absence of an object to the vehicle control apparatus 30 connected so that communication was possible. When the position of the object is obtained, the detection unit 14 outputs the position of the object to the vehicle control device 30.

  In response to the detection result received from the detection unit 14, the vehicle control device 30 emits a warning sound that notifies that an object is present. When the position of the object is obtained, the position of the object is displayed on the display device provided in the moving body 200. Furthermore, in the first function, the speed of the moving body 200 is controlled or the brake is controlled according to the detection result.

  As described above, the transmission control unit 13 transmits ultrasonic waves from each of the ultrasonic sensors 20A and 20B while switching between the first transmission time length and the second transmission time length. Normally, the longer the time for transmitting ultrasonic waves, the wider the space to be detected. For example, the wave receiving unit 22 of the ultrasonic sensor 20A can receive a reflected wave in the space E1 with respect to the ultrasonic wave transmitted with the first transmission time length (see FIG. 2). Further, the wave receiving unit 22 of the ultrasonic sensor 20B can receive the reflected wave in the space E2 with respect to the ultrasonic wave transmitted with the first transmission time length (see FIG. 2). That is, when the ultrasonic sensor 20A transmits ultrasonic waves with the first transmission time length, the space that can be received by both the wave receiving unit 22 of the ultrasonic sensor 20A and the wave receiving unit 22 of the ultrasonic sensor 20B is A common space E3 of the space E1 and the space E2 (see FIG. 2). In addition, since the object existing outside the vehicle width does not affect driving assistance (such as preventing rear-end collision), the common space E3 is preferably within the vehicle width of the moving body 200.

  On the other hand, when the ultrasonic sensor 20A transmits an ultrasonic wave with the second transmission time length, the space E10 becomes a detection target space (see FIG. 2). When the ultrasonic sensor 20B transmits ultrasonic waves for the second transmission time length, the space E11 becomes a detection target space (see FIG. 2). Since the spaces E10 and E11 are narrower than the spaces E1 and E2, the spaces E10 and E11 are used for the second function. In the second function, in order to detect the presence or absence of an object around the moving body 200, it is preferable that the spaces E10 and E11 include a region outside the vehicle width of the moving body 200.

  Next, the basic operation of the object detection system 100 will be described.

  First, the object detection operation when an ultrasonic wave is transmitted with the first transmission time length will be described. Here, the case where the ultrasonic sensor 20A transmits ultrasonic waves will be described.

  The transmission control unit 13 generates a drive signal having a predetermined frequency, and outputs the generated drive signal to the drive unit 23 of the ultrasonic sensor 20A with the first transmission time length. When the drive unit 23 receives the drive signal from the transmission control unit 13 with the first transmission time length, the transmission unit 21 of the ultrasonic sensor 20A vibrates at a predetermined frequency, and the ultrasonic wave has the first transmission time length. The electric signal based on the drive signal is output to the wave transmission unit 21 so as to be transmitted. The wave transmission unit 21 of the ultrasonic sensor 20 </ b> A vibrates at a predetermined frequency in accordance with an electric signal from the drive unit 23 and transmits an ultrasonic wave with a first transmission time length. FIG. 3A shows a waveform W1 (waveform of an electrical signal) of an ultrasonic wave transmitted by the wave transmission unit 21 of the ultrasonic sensor 20A with the first transmission time length. The time length X1 shown in FIG. 3A corresponds to the first transmission time length.

  The wave receiving unit 22 of the ultrasonic sensor 20A receives the reflected wave of the ultrasonic wave transmitted by the wave transmitting unit 21 of the ultrasonic sensor 20A, converts it to an electric signal, and converts it into an analog signal to the object detection device 10. Output. Here, the received wave intensity of the reflected wave (converted electrical signal) received by the wave receiving unit 22 may be too high or too low, thereby hindering object detection. Therefore, the storage unit 12 of the object detection device 10 stores a correction value for correcting the received intensity of the electric signal according to the combination of the function to operate and the detection space (detection range).

  The processing unit 11 corrects the electric signal received from the wave receiving unit 22 of the ultrasonic sensor 20A using a correction value corresponding to the detection space. The processing unit 11 converts the corrected electrical signal from an analog signal to a digital signal by an AD (Analog to Digital) converter. The waveform W10 of the reflected wave converted into a digital signal by the AD converter is shown in FIG. 3B.

  The wave receiving unit 22 of the ultrasonic sensor 20B receives the reflected wave of the ultrasonic wave transmitted by the wave transmitting unit 21 of the ultrasonic sensor 20A, converts it to an electric signal, and converts it into an analog signal to the object detection device 10. Output.

  The processing unit 11 corrects the electric signal received from the wave receiving unit 22 of the ultrasonic sensor 20B using a correction value corresponding to the detection space. The processing unit 11 converts the corrected electrical signal from an analog signal to a digital signal by an AD converter. The waveform W11 of the reflected wave converted into a digital signal by the AD converter is shown in FIG. 3B. Since the distance from the wave receiving part 22 of the ultrasonic sensor 20B to the object is longer than the distance from the wave receiving part 22 of the ultrasonic sensor 20A to the object, the waveform W11 appears later than the waveform W10.

  First, the detection unit 14 detects an object from each of the waveform W10 and the waveform W11. When an object is detected in the detection space, in the waveform W10 and the waveform W11, the received wave intensity at the time when the reflected wave reflected by the object is received is smaller than the received wave intensity for the previous and subsequent times. Therefore, the detection unit 14 detects the presence of an object when the received wave intensity is lower than the first threshold value T1 as compared with the first threshold value T1 with respect to the received wave intensity (voltage). In the present embodiment, the first threshold value T1 changes along the time axis so as to increase stepwise until the detection process ends (see FIG. 3B).

  Next, the operation of object detection when ultrasonic waves are transmitted with the second transmission time length will be described. Here, the case where the ultrasonic sensor 20A transmits ultrasonic waves will be described.

  The transmission control unit 13 generates a drive signal having a predetermined frequency, and outputs the generated drive signal to the drive unit 23 of the ultrasonic sensor 20A with the second transmission time length. When the drive unit 23 receives the drive signal from the transmission control unit 13 with the second transmission time length, the transmission unit 21 of the ultrasonic sensor 20A vibrates at a predetermined frequency, and the ultrasonic wave has the second transmission time length. The electric signal based on the drive signal is output to the wave transmission unit 21 so as to be transmitted. The wave transmission unit 21 of the ultrasonic sensor 20 </ b> A vibrates at a predetermined frequency in accordance with an electric signal from the drive unit 23 and transmits an ultrasonic wave with the second transmission time length. FIG. 3C shows a waveform W2 (electric signal waveform) of an ultrasonic wave transmitted by the transmission unit 21 with the second transmission time length. The time length X2 shown in FIG. 3C corresponds to the second transmission time length. Here, the frequency of the ultrasonic wave transmitted in the second function is the same as the frequency of the ultrasonic wave transmitted in the first function.

  The wave receiving unit 22 receives the reflected wave of the ultrasonic wave transmitted by the wave transmitting unit 21, converts it into an electrical signal, and outputs it as an analog signal to the object detection device 10.

  The processing unit 11 corrects the electrical signal received from the wave receiving unit 22 using a correction value corresponding to the detection space. The processing unit 11 converts the corrected electrical signal from an analog signal to a digital signal by an AD converter. The waveform W20 of the reflected wave converted into a digital signal by the AD converter is shown in FIG. 3D. When an object is detected in the detection space, in the waveform W20, the received wave intensity at the time when the reflected wave reflected by the ultrasonic wave is received is compared with the received wave intensity for the previous and subsequent times, for example, the broken line of the waveform W20. As small as the part.

  The detection unit 14 detects an object around the moving body 200 using the waveform W20. Specifically, the presence of an object is detected when the received wave intensity is lower than the second threshold value T2 as compared with the second threshold value T2 with respect to the received wave intensity (voltage). In the present embodiment, the second threshold T2 changes so as to increase stepwise along the time axis until the detection process is completed (see FIG. 3D). For example, in FIG. 3D, when the waveform is a broken line at time a1, it is smaller than the second threshold T2, and therefore the detection unit 14 transmits an ultrasonic wave assuming that the object exists. The distance to the object is determined based on the time (wave reception time) from time to time a1.

  In the present embodiment, the object detection system 100 has the first function and the second function as described above.

  When the object detection system 100 operates as the first function, the detection method of the presence / absence of an object includes detection of the presence / absence of an object in a wide range (long distance) (detection for a long distance) and an object in a narrow range (short distance). And the presence / absence detection (short distance detection). When the operation as the first function is started, the object detection system 100 performs detection for a long distance. Specifically, the transmission control unit 13 of the object detection apparatus 10 controls the ultrasonic sensor 20 so that the ultrasonic sensor 20 transmits ultrasonic waves with the first transmission time length. The detection unit 14 of the object detection device 10 detects the presence or absence of an object based on the reflected wave of the ultrasonic wave transmitted for the first transmission time length. In the detection for long distance, the object detection system 100 switches the detection method to detection for short distance when the distance of the detected object is equal to or less than a predetermined value (for example, 1 m or less). When the detection method is switched to short-distance detection, the transmission control unit 13 causes the ultrasonic sensor 20 to be super-long with a transmission time length shorter than the first transmission time length (for example, the second transmission time length). The ultrasonic sensor 20 is controlled so as to transmit a sound wave. The detection unit 14 of the object detection device 10 detects the presence or absence of an object based on the reflected wave of the ultrasonic wave transmitted with the second transmission time length.

  In the present embodiment, the detection time length differs between the long-distance object detection of the first function and the short-distance object detection of the first function. For example, in the long-distance object detection of the first function, the detection unit 14 detects an object (detection process) with a first detection time length from when the ultrasonic wave is transmitted until the first time elapses. . In the first-function short-distance object detection, the detection unit 14 performs the detection process with the second detection time length from when the ultrasonic wave is transmitted until the second time shorter than the first time elapses. Further, the first threshold T1 used for the long-distance object detection of the first function and the short-distance object detection of the first function may be different or may be the same first threshold T1. Good. In the present embodiment, the first threshold T1 used in the long distance object detection in the first function and the short distance object detection in the first function is the same.

  In the present embodiment, in the detection method of the presence / absence of an object when the object detection system 100 operates as the second function, the detection unit 14 performs object detection for long distances as in the case of operating as the first function. And object detection for short distances. Also in this case, as in the case of operating as the first function, the detection time length is different between the long-distance object detection of the second function and the short-distance object detection of the second function. For example, in the long-distance object detection of the second function, the detection unit 14 performs the detection process with the third detection time length from when the ultrasonic wave is transmitted until the third time elapses. In the short-distance object detection of the second function, the detection unit 14 performs the detection process with a fourth detection time length from when the ultrasonic wave is transmitted until a fourth time shorter than the third time elapses. The second threshold T2 used for the long-distance object detection of the second function and the short-distance object detection of the second function may be different or may be the same second threshold T2. In the present embodiment, the second threshold T2 used for the long-distance object detection of the second function and the short-distance object detection of the second function are different.

  Next, the operation of the object detection system 100 using both the first function and the second function will be described with reference to FIG.

  The object detection system 100 operates as the first function and the second function using the ultrasonic wave transmitted from the ultrasonic sensor 20A in the period t1 illustrated in FIG. 4, and the first function (driving support function) and the second function are performed. Long-distance object detection is performed as a function (peripheral object detection function). First, the transmission control unit 13 controls the ultrasonic sensor 20A so as to transmit ultrasonic waves to the ultrasonic sensor 20A with the first transmission time length.

  The processing unit 11 performs correction and digital conversion on the electric signal corresponding to the reflected wave received by the wave receiving unit 22 of the ultrasonic sensor 20A, and acquires the electric signal (first received signal). The detection unit 14 compares the voltage (received intensity) of the first received signal with the first threshold value T1 corresponding to the elapsed time since the ultrasonic sensor 20A transmits the ultrasonic wave, and determines the common space. In E3, the presence or absence of an object is detected. The detection unit 14 determines that an object exists when the received wave intensity is equal to or lower than the first threshold T1, and determines that no object exists when the received wave intensity is greater than the first threshold T1. If the detection unit 14 determines that an object is present, the detection unit 14 is based on the time from when the ultrasonic sensor 20A transmits an ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20A receives the reflected wave. To obtain the distance to the detected object.

  The processing unit 11 performs correction and digital conversion on the electric signal corresponding to the reflected wave received by the wave receiving unit 22 of the ultrasonic sensor 20B, and acquires an electric signal (second received signal). The detecting unit 14 compares the voltage (received intensity) of the second received signal with the first threshold value T1 corresponding to the elapsed time after the ultrasonic sensor 20A transmits the ultrasonic wave, and determines the common space. In E3, the presence or absence of an object is detected. If the detection unit 14 determines that an object is present, the detection unit 14 is based on the time from when the ultrasonic sensor 20A transmits an ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20B receives the reflected wave. To obtain the distance to the detected object.

  When the object is detected from both the first received signal and the second received signal, the detecting unit 14 obtains the position of the object by triangulation.

  The detection unit 14 performs the above processing until the first detection time length described above has elapsed in the period t1.

  Next, the detection unit 14 detects the object in the vicinity, that is, the length in the second function (peripheral object detection function) based on the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20A for the first transmission time length. Performs object detection for distance.

  In this case, the processing unit 11 is for a long distance in the second function (peripheral object detection function) with respect to the electrical signal corresponding to the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20A with the first transmission time length. Correction using a correction value corresponding to the object detection and digital conversion are performed to obtain an electric signal (third received signal).

  The detection unit 14 compares the voltage (received intensity) of the third received signal with the second threshold value T2 corresponding to the elapsed time after the ultrasonic sensor 20A transmits the ultrasonic wave, The presence or absence of an object in the space E10) is detected. The detection unit 14 determines that an object exists in the vicinity when the received wave intensity is equal to or lower than the second threshold T2, and determines that no object exists in the vicinity when the received wave intensity is greater than the second threshold T2. If the detection unit 14 determines that an object is present, the detection unit 14 is based on the time from when the ultrasonic sensor 20A transmits an ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20A receives the reflected wave. To obtain the distance to the detected object. The detection unit 14 performs the above processing until the above-described third detection time length elapses during the period t1.

  The object detection system 100 operates as the first function and the second function using the ultrasonic sensor 20B in the period t2 shown in FIG. 4, and performs long-distance object detection as the first function and the second function. The transmission control unit 13 controls the ultrasonic sensor 20B so as to transmit ultrasonic waves to the ultrasonic sensor 20B with the first transmission time length. The processing unit 11 performs correction and digital conversion on the electric signal corresponding to the reflected wave received by the wave receiving unit 22 of the ultrasonic sensor 20B, and acquires an electric signal (fourth received signal). The detection unit 14 compares the voltage (received intensity) of the third received signal with the first threshold value T1 corresponding to the elapsed time after the ultrasonic sensor 20B transmits the ultrasonic wave, and determines the common space. In E3, the presence or absence of an object is detected. If the detection unit 14 determines that an object is present, the ultrasonic sensor 20B transmits the ultrasonic wave after the transmission unit 21 of the ultrasonic sensor 20B transmits the reflected wave. The distance to the detected object is obtained based on the time until the detection.

  The processing unit 11 performs correction and digital conversion on the electric signal corresponding to the reflected wave received by the wave receiving unit 22 of the ultrasonic sensor 20A, and acquires the electric signal (fifth received signal). The detection unit 14 compares the voltage (received intensity) of the fifth received signal with the first threshold value T1 corresponding to the elapsed time since the ultrasonic sensor 20B transmits the ultrasonic wave, and determines the common space. In E3, the presence or absence of an object is detected. When the detection unit 14 determines that an object is present, the detection unit 14 is based on the time from when the ultrasonic sensor 20B transmits an ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20A receives the reflected wave. To obtain the distance to the detected object.

  When the object is detected from both the fourth received signal and the fifth received signal, the detecting unit 14 obtains the position of the object by triangulation.

  The detection unit 14 performs the above-described processing until the above-described first detection time length elapses during the period t2.

  Next, similarly to the period t1, the detection unit 14 further detects an object (first) in the vicinity (space E11) based on the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20B with the first transmission time length. Long-distance object detection in two functions).

  In this case, the processing unit 11 is for a long distance in the second function (peripheral object detection function) with respect to the electrical signal corresponding to the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20B with the first transmission time length. Then, correction using a correction value corresponding to the object detection and digital conversion are performed to obtain an electrical signal (sixth received signal).

  The detecting unit 14 compares the voltage (received intensity) of the sixth received signal with the second threshold value T2 corresponding to the elapsed time since the ultrasonic sensor 20B transmitted, and the presence / absence of an object in the vicinity Is detected. When the detection unit 14 detects the presence of an object, the time from when the ultrasonic sensor 20B transmits an ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20B receives the reflected wave. Based on the above, the distance to the detected object is obtained. The detection unit 14 performs the above process until the above-described third detection time length elapses during the period t2.

  The object detection system 100 operates as a second function using the ultrasonic sensor 20A during the period t3 shown in FIG. The transmission control unit 13 controls the ultrasonic sensor 20A so as to transmit ultrasonic waves to the ultrasonic sensor 20A with the second transmission time length.

  The processing unit 11 detects an object for short distance in the second function (peripheral object detection function) with respect to an electrical signal corresponding to the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20A with the second transmission time length. The electric signal (seventh received signal) is acquired by performing correction and digital conversion using the correction value according to the above.

  The detection unit 14 compares the voltage (received intensity) of the seventh received signal with the second threshold value T2 corresponding to the elapsed time after the ultrasonic sensor 20A transmits the ultrasonic wave, Detects the presence of an object. If the detection unit 14 determines that an object is present, the detection unit 14 is based on the time from when the ultrasonic sensor 20A transmits an ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20A receives the reflected wave. To obtain the distance to the detected object. The detection unit 14 performs the above process until the above-described fourth detection time length elapses during the period t3.

  The object detection system 100 operates as a second function using the ultrasonic sensor 20B in the period t4 shown in FIG. 4, and performs object detection for a short distance. The transmission control unit 13 controls the ultrasonic sensor 20A so as to transmit ultrasonic waves to the ultrasonic sensor 20B with the second transmission time length.

  The processing unit 11 detects an object for short distance in the second function (peripheral object detection function) with respect to the electrical signal corresponding to the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20B with the second transmission time length. The electric signal (eighth received signal) is acquired by performing correction using the correction value according to the above and digital conversion.

  The detection unit 14 compares the voltage (received intensity) of the eighth received signal with the second threshold value T2 corresponding to the elapsed time after the ultrasonic sensor 20B transmits the ultrasonic wave, Detects the presence of an object. When the detection unit 14 detects an object, based on the time from when the ultrasonic sensor 20B transmits the ultrasonic wave to when the reception unit 22 of the ultrasonic sensor 20B receives the reflected wave, Find the distance to the detected object. The detection unit 14 performs the above process until the above-described fourth detection time length elapses during the period t4.

  Thereafter, the object detection system 100 repeats the operation from the period t1 to the period t4. For example, the object detection system 100 executes the first function and the second function using the ultrasonic wave transmitted with the first transmission time length in the ultrasonic sensor 20A in the period t5 shown in FIG. In the period t6, the object detection system 100 performs the first function and the second function using the ultrasonic wave transmitted by the ultrasonic sensor 20B with the first transmission time length. In the period t7, the object detection system 100 executes the second function using the ultrasonic wave transmitted by the ultrasonic sensor 20A with the second transmission time length. In the period t8, the object detection system 100 executes the second function using the ultrasonic wave transmitted by the ultrasonic sensor 20B with the second transmission time length.

  Note that, in the periods t1, t2, t5, and t6 shown in FIG. 4, as described above, the near-distance object detection in the first function may be performed. For example, when the distance of the object detected in the periods t1 and t2 is equal to or less than a predetermined value (1 m or less), the object detection for the short distance in the first function is performed in the periods t5 and t6.

  Hereinafter, in the period t1, the operation in the case of performing short-distance object detection in the first function using the ultrasonic wave transmitted by the ultrasonic sensor 20A will be described.

  In the period t1, the transmission control unit 13 transmits the ultrasonic wave to the ultrasonic sensor 20A with a time length shorter than the first transmission time length (for example, the second transmission time length). 20A is controlled. The processing unit 11 performs correction and digital conversion on the electrical signal corresponding to the reflected wave received by the wave receiving unit 22 of the ultrasonic sensor 20A, and acquires the electrical signal (the ninth received signal). The detection unit 14 compares the voltage (received intensity) of the ninth received signal with the first threshold value T1 corresponding to the elapsed time after the ultrasonic sensor 20A transmits the ultrasonic wave, Detect the presence or absence. When the detection unit 14 detects an object, based on the time from when the ultrasonic sensor 20A transmits the ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20A receives the reflected wave, Find the distance to the detected object. The detection unit 14 performs the above-described processing until the above-described second detection time length elapses during the period t1.

  Further, the detection unit 14 further detects an object in the vicinity (object detection for a short distance in the peripheral object detection function) based on the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20A with the second transmission time length. Also do.

  In this case, the processing unit 11 responds to the long-distance object detection in the peripheral object detection function with respect to the electrical signal corresponding to the reflected wave of the ultrasonic wave transmitted by the ultrasonic sensor 20A with the second transmission time length. The electric signal (tenth received signal) is obtained by performing correction using the correction value and digital conversion.

  The detection unit 14 compares the voltage (received intensity) of the tenth received signal with the second threshold value T2 corresponding to the elapsed time after the ultrasonic sensor 20A transmits the ultrasonic wave, Detects the presence of an object. When the detection unit 14 detects an object, based on the time from when the ultrasonic sensor 20A transmits the ultrasonic wave until the reception unit 22 of the ultrasonic sensor 20A receives the reflected wave, Find the distance to the detected object. The detection unit 14 performs the above-described processing until the above-described fourth detection time length elapses during the period t1.

  In addition, in the short-distance object detection in the first function using the ultrasonic wave transmitted by the ultrasonic sensor 20A, together with the detection result using the reflected wave received by the wave receiving unit 22 of the ultrasonic sensor 20B. The position of the object may be obtained.

  In addition, since the operation when the object detection for short distance in the first function is performed on the ultrasonic sensor 20B is the same operation as described above, the description thereof is omitted here.

  As described above, the object detection system 100 uses the detection based on the ultrasonic wave transmitted in the first transmission time zone and the ultrasonic wave transmitted in the second transmission time zone in the peripheral object detection function. Based detection. Therefore, there is no period in which object detection by the peripheral object detection function is not performed in each period in which the object is detected. Thereby, the object detection system 100 can perform the detection based on the standard about the peripheral object detection function.

  Conventionally, two ultrasonic sensors for detecting peripheral objects are provided at the corners of the bumper, and two ultrasonic sensors for driving support are provided at the central portion of the bumper. Is realized. On the other hand, in the present embodiment, since the peripheral object detection function and the driving support function are realized using the two ultrasonic sensors 20, the number of parts is small. As a result, the cost of the object detection system can be reduced.

(5) Modifications Modifications are listed below. Note that the modifications described below can be applied in appropriate combination with the above embodiments.

  In the above embodiment, the transmission control unit 13 is configured to switch between two time lengths of the first transmission time length and the second transmission time length, but is not limited to this configuration. The transmission control unit 13 may perform switching of three or more time lengths. Thereby, the object detection system 100 can perform object detection for each of the detection spaces corresponding to the short distance, the medium distance, the long distance, and the three distances.

  In the above embodiment, the frequency of the ultrasonic wave transmitted in the first transmission time length is the same as the frequency of the ultrasonic wave transmitted in the second transmission time length. However, the present invention is not limited to this. The frequency of the ultrasonic wave transmitted in the first transmission time length may be different from the frequency of the ultrasonic wave transmitted in the second transmission time length.

  In the above embodiment, the object detection device 10 is configured to use the time length for transmitting an ultrasonic wave as the second transmission time length when performing short-distance object detection in the driving support function, but is limited to this configuration. Not. In the object detection device 10, the time length for transmitting an ultrasonic wave in the case of performing short-distance object detection in the driving support function may be a time length shorter than the first transmission time length.

  In the above embodiment, the number of ultrasonic sensors 20 is two, but the present invention is not limited to this configuration. The number of ultrasonic sensors 20 may be one or more.

  In the above embodiment, the reflected wave of the ultrasonic wave transmitted from each of the ultrasonic sensor 20A and the ultrasonic sensor 20B is received by the wave receiving unit 22 of the ultrasonic sensor 20A and the wave receiving unit 22 of the ultrasonic sensor 20B. However, the present invention is not limited to this configuration. Only the receiving portion 22 of the ultrasonic sensor 20A receives the reflected ultrasonic wave transmitted from the ultrasonic sensor 20A, and the reflected ultrasonic wave transmitted from the ultrasonic sensor 20B is received by the ultrasonic sensor 20B. Only the wave receiving unit 22 may receive the wave. In this case, the detection unit 14 performs the object detection based on the ultrasonic wave transmitted from the ultrasonic sensor 20A and the object detection based on the ultrasonic wave transmitted from the ultrasonic sensor 20B, and then from both reflected waves. When the object is detected, the position of the object is obtained.

  In the above-described embodiment, the drive signal is generated by the transmission control unit 13 of the object detection apparatus 10, but the present invention is not limited to this configuration. Another component, for example, the drive unit 23 of the ultrasonic sensor 20 may generate the drive signal.

  The communication method between the object detection apparatus 10 and the ultrasonic sensor 20 is not particularly limited, and may be, for example, the LIN communication described above or another communication method.

  In the said embodiment, although the ultrasonic sensor 20 was set as the structure attached to the rear bumper of the mobile body 200 (automobile), it is not limited to this structure. The ultrasonic sensor 20 may be attached to the front bumper of the moving body 200 (automobile) or may be attached to the side surface of the moving body 200 (automobile).

  In the said embodiment, although it was set as the motor vehicle as an example of the mobile body 200, it is not limited to this illustration. The moving body 200 may be a golf course cart. The moving body 200 may be any vehicle that moves by driving a person.

(Summary)
As described above, the object detection device 10 according to the first aspect includes the wave transmission control unit 13 and the detection unit 14. The transmission control unit 13 switches the transmission of ultrasonic waves from the transmission unit 21 among a plurality of transmission time lengths (first transmission time length and second transmission time length) for transmitting the ultrasonic waves. The transmission unit 21 is controlled to repeat. The detection unit 14 detects an object in the detection area (detection space) based on the reception time from when the ultrasonic wave is transmitted until the reception unit 22 receives the reflected wave of the ultrasonic wave. .

  According to this configuration, the object detection apparatus 10 switches the range in which the ultrasonic waves reach by switching the transmission time length for transmitting the ultrasonic waves. That is, the object detection apparatus 10 can switch the detection area (detection space) by switching the transmission time length for transmitting the ultrasonic wave. Thus, in order to secure a space for detecting objects at short distance and a space for detecting objects at long distance, the frequency used for detecting objects at short distance and the frequency used for detecting objects at long distance There is no need to increase the difference. Therefore, the object detection apparatus 10 performs short-distance object detection and long-distance object detection while reducing the difference between the frequency used for short-distance object detection and the frequency used for long-distance object detection. Can do.

  Conventionally, the difference between the frequency used for object detection at a distance and the frequency used for object detection at a long distance becomes large, which may complicate circuit design such as modulation processing. On the other hand, in the object detection apparatus 10 described above, the difference between the frequency used for object detection at a distance and the frequency used for object detection at a long distance can be reduced. Is less likely to be complicated.

  In the object detection device 10 of the second aspect, in the first aspect, the detection unit 14 is associated with each of a plurality of transmission time lengths (first transmission time length, second transmission time length), and An object is detected using a plurality of threshold values (first threshold value T1 and second threshold value T2) for the received wave intensity of the ultrasonic wave.

  According to this configuration, the object detection apparatus 10 detects an object using a plurality of threshold values, and thus can detect an object with higher accuracy.

  In the object detection device 10 of the third aspect, in the second aspect, each of the plurality of threshold values changes with respect to the time axis direction until the object detection processing by the detection unit 14 is completed.

  According to this configuration, since the object detection device 10 changes each of the plurality of threshold values with respect to the time axis direction, the threshold value can be arbitrarily set with respect to the time axis direction. Moreover, the detection range can be gradually expanded by increasing the threshold value. Therefore, more accurate object detection can be performed.

  In the object detection device 10 according to the fourth aspect, in the second or third aspect, the detection unit 14 uses a threshold corresponding to the transmission time length switched by the transmission control unit 13 among the plurality of thresholds. Detect objects.

  According to this configuration, the object detection apparatus 10 uses the threshold value corresponding to the transmission time length, and thus can perform object detection with higher accuracy.

  In the object detection device 10 of the fifth aspect, in any one of the first to fourth aspects, there are a plurality of the wave transmission units 21. There are a plurality of wave receivers 22, and each correspond to a plurality of wave transmitters 21. The transmission control unit 13 controls the plurality of transmission units 21 to repeat the transmission of each ultrasonic wave of the transmission unit 21 while switching the plurality of transmission time lengths. The detection unit 14 detects an object in the detection area for each wave reception unit 22 based on the reception time for the ultrasonic wave transmitted by the corresponding wave transmission unit 21.

  According to this configuration, the object detection device 10 performs object detection based on each of the ultrasonic waves transmitted from the plurality of wave transmission units 21, and thus can perform object detection with higher accuracy.

  In the object detection apparatus 10 according to the sixth aspect, in the fifth aspect, the plurality of transmission time lengths include a first transmission time length and a second transmission time length shorter than the first transmission time length. Including. The transmission control unit 13 sequentially controls the plurality of transmission units 21 so that each of the transmission units 21 transmits ultrasonic waves with the first transmission time length. The detection unit 14 receives a time for receiving an ultrasonic wave transmitted by the corresponding transmission unit 21 with the first transmission time length after each of the transmission units 21 transmits the ultrasonic wave with the first transmission time length. Based on the above, an object within the detection area is detected for each wave receiving unit 22. If the detection results in at least two of the plurality of reception units 22 indicate that the detection unit 14 has detected an object, the detection unit 14 detects the object from a combination of the detection results in the at least two reception units 22 Find the position of. The transmission control unit 13 sequentially controls the plurality of transmission units 21 so that each of the transmission units 21 transmits ultrasonic waves with the second transmission time length. After each of the transmission units transmits ultrasonic waves with the first transmission time length, the detection unit 14 determines the reception time for the ultrasonic waves transmitted by the corresponding transmission unit 21 with the second transmission time length. Based on this, an object within the detection area is detected for each wave receiving unit 22.

  According to this configuration, the object detection device 10 detects the presence / absence of an object for each wave receiving unit 22, and obtains the position of the object from the combination of the wave receiving units 22. Thereby, object detection with higher accuracy can be performed.

  In the object detection apparatus 10 according to the seventh aspect, in any one of the first to sixth aspects, the frequencies of the ultrasonic waves transmitted with a plurality of transmission time lengths are the same.

  According to this configuration, since the object detection apparatus 10 uses the same frequency for the ultrasonic waves transmitted with a plurality of transmission time lengths, it is not necessary to perform different filter processing for each ultrasonic wave to be transmitted. . Conventionally, since the frequency of the ultrasonic wave is switched to switch the detection area, it is necessary to provide a different filter process for each detection area, and the configuration may be complicated. However, in the object detection apparatus 10 of the present embodiment, it is only necessary to perform the same filtering process for all the detection areas, and therefore it is not necessary to provide a different filtering process for each detection area. Therefore, the possibility that the configuration is complicated can be reduced as compared with the conventional case. Further, by setting the frequencies of the ultrasonic waves transmitted in a plurality of transmission time lengths to be the same, the Q value can be increased, the sensitivity can be increased, and the S / N ratio can be improved.

  The object detection system 100 according to the eighth aspect includes the object detection device 10 according to any one of the first to seventh aspects, and a wave transmission unit 21 and a wave reception unit 22.

  According to this configuration, the object detection system 100 switches the range in which the ultrasonic wave reaches by switching the transmission time length for transmitting the ultrasonic wave. That is, the object detection system 100 can switch the detection area (detection space) by switching the transmission time length for transmitting the ultrasonic wave.

  The moving body 200 according to the ninth aspect includes the object detection system 100 according to the eighth aspect.

  According to this configuration, the moving body 200 switches the range in which the ultrasonic wave reaches by switching the transmission time length for transmitting the ultrasonic wave. That is, the moving body 200 can switch the detection area (detection space) by switching the transmission time length for transmitting the ultrasonic wave.

DESCRIPTION OF SYMBOLS 10 Object detection apparatus 13 Transmission control part 14 Detection part 20 Ultrasonic sensor 21 Transmission part 22 Reception part 100 Object detection system 200 Mobile body T1 1st threshold value T2 2nd threshold value E3 Common space (detection space, detection area)
E10, E11 space (detection space, detection area)

Claims (9)

A transmission control unit for controlling the transmission unit to repeat the transmission of the ultrasonic wave from the transmission unit while switching a plurality of transmission time lengths for transmitting the ultrasonic wave;
A detection unit that detects an object in a detection area based on a reception time from when the ultrasonic wave is transmitted until the reception unit receives the reflected wave of the ultrasonic wave. An object detection device. The detector is
The object detection apparatus according to claim 1, wherein the object detection is performed using a plurality of threshold values corresponding to the plurality of transmission time lengths and corresponding to the reception intensity of the ultrasonic wave. The object detection apparatus according to claim 2, wherein each of the plurality of threshold values changes with respect to a time axis direction until the object detection processing by the detection unit is completed. The detector is
The object detection apparatus according to claim 2 or 3, wherein the object is detected using a threshold corresponding to the transmission time length switched by the transmission control unit among the plurality of thresholds. There are a plurality of the transmission units,
There are a plurality of the receiving units, and each of the receiving units corresponds to the plurality of transmitting units,
The wave transmission control unit
For the plurality of transmission units, control to repeat the transmission of each ultrasonic wave of the transmission unit while switching the plurality of transmission time lengths,
The detector is
The detection of the object in a detection area is performed for every said receiving part based on the said receiving time with respect to the said ultrasonic wave which the said corresponding transmitting part transmitted, The any one of Claims 1-4 characterized by the above-mentioned. The object detection apparatus according to claim 1. The plurality of transmission time lengths include a first transmission time length and a second transmission time length shorter than the first transmission time length,
The wave transmission control unit
Sequentially controlling the plurality of transmission units such that each of the transmission units transmits the ultrasonic wave with the first transmission time length,
The detector is
After each of the transmission units transmits the ultrasonic wave with the first transmission time length, the reception time for the ultrasonic wave transmitted by the corresponding transmission unit with the first transmission time length. Based on the detection of the object in the detection area for each of the receiving unit,
When the detection results in at least two of the plurality of receiving units indicate that an object has been detected, the position of the object is obtained from the combination of the detection results in the at least two receiving units. ,
The wave transmission control unit
Sequentially controlling the plurality of transmission units such that each of the transmission units transmits the ultrasonic wave with the second transmission time length;
The detector is
After each of the transmission units transmits the ultrasonic wave with the first transmission time length, the reception time with respect to the ultrasonic wave transmitted by the corresponding transmission unit with the second transmission time length The object detection device according to claim 5, wherein an object in a detection area is detected for each of the wave receiving units based on the above. The object detection apparatus according to any one of claims 1 to 6, wherein the frequencies of the ultrasonic waves transmitted in the plurality of transmission time lengths are the same. The object detection device according to any one of claims 1 to 7,
The object detection system comprising the wave transmission unit and the wave reception unit. A moving body comprising the object detection system according to claim 8.