Object detection device

Abstract

To avoid interference of an ultrasonic wave surely even when other vehicle loads the same object detection device as an own vehicle.SOLUTION: An object detection device comprises: a control unit that controls to make a transreceiving unit transmitting a transmission wave, and receiving a reception wave generating because the transmission wave is reflected upon the object transmit the transmission wave at a prescribed transmission timing; a distance calculation unit that calculates a distance to the object on the basis of the transmission wave and reception wave; and a determination unit that determines a random time serving as a standby time for shifting the transmission timing in accordance with each of a normal state where the distance to the object is larger than a first distance, or the object is not detected, a first approach state where the distance to the object is equal to or less than the first distance, and a second approach state where the distance to the object is equal to or less than a second distance smaller than the first distance. The control unit is configured to control the transreceiving unit so as to transmit the transmission wave at a new transmission timing having the transmission timing delayed by the determined random time.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to an object detection device. [Background technology]

[0002] In vehicle control systems and the like, object detection devices are used that detect objects present around the vehicle by transmitting transmission waves such as ultrasonic waves from the vehicle and receiving reception waves (reflected waves) generated when the transmission waves are reflected by the object.

[0003] In such an object detection device, if the timing of transmitting ultrasonic waves between the subject vehicle and another vehicle has a certain relationship, interference may occur in which the ultrasonic waves transmitted by the other vehicle are mistaken for those transmitted by the subject vehicle. Conventional technology avoids such interference by changing the timing of transmitting ultrasonic waves from the subject vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6413620 [Patent Document 2] Japanese Patent Application Publication No. 2018-59826 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the subject vehicle is experiencing interference, the other vehicle is also experiencing interference from the subject vehicle's ultrasonic waves. Therefore, with this conventional technology, if the subject vehicle and the other vehicle are both equipped with the same object detection device that uses the same interference avoidance method, the subject vehicle and the other vehicle may end up avoiding interference with each other, resulting in the timing of transmitting ultrasonic waves coinciding, and thus making it impossible to avoid interference. [Means for solving the problem]

[0006] An object detection device of an embodiment is an object detection device that is mounted on a vehicle and detects objects present in the vicinity of the vehicle, and includes: a control unit that controls a transceiver unit that transmits a transmission wave and receives a reception wave generated when the transmission wave is reflected by the object to transmit the transmission wave at a predetermined transmission timing; a distance calculation unit that calculates the distance to the object based on the transmission wave and the reception wave; and a determination unit that determines a random time, which is a waiting time for shifting the transmission timing, depending on each of a normal state in which the distance to the object is greater than a first distance or the object is not detected, a first approach state in which the distance to the object is equal to or less than the first distance, and a second approach state in which the distance to the object is equal to or less than a second distance that is smaller than the first distance, and the control unit controls the transceiver unit to transmit the transmission wave at a new transmission timing that is delayed by the determined random time.

[0007] With this configuration, for example, even if another vehicle is equipped with the same object detection device as the host vehicle, it is possible to reliably avoid interference of ultrasonic waves.

[0008] In addition, in the object detection device of the embodiment, the first distance is smaller than a distance based on the difference between the random time corresponding to the first approach state and the random time corresponding to the normal state, and the second distance is smaller than a distance based on the difference between the random time corresponding to the second approach state and the random time corresponding to the normal state, and the determination unit determines the random time according to the normal state after the control unit transmits a transmission wave at the new transmission timing in the first approach state or the second approach state.

[0009] With this configuration, for example, even if another vehicle is equipped with the same object detection device as the host vehicle, it becomes possible to more reliably avoid interference.

[0010] In addition, in the object detection device of the embodiment, the determination unit determines the random time of the transmission wave from the transceiver unit provided at the front of the vehicle and the random time of the transmission wave from the transceiver unit provided at the rear of the vehicle to be different times.

[0011] With this configuration, for example, even if another vehicle is equipped with the same object detection device as the subject vehicle, it is possible to reliably avoid interference of ultrasonic waves depending on the direction of travel of the vehicle.

[0012] In addition, the object detection device of the embodiment further includes a memory unit that stores random information in which a random time is determined corresponding to each of the normal state, the first approach state, and the second approach state, and the determination unit determines the random time based on the normal state, the first approach state, the second approach state, and the random information.

[0013] With this configuration, for example, even if another vehicle is equipped with the same object detection device as the host vehicle, it becomes possible to easily and more reliably avoid interference of ultrasonic waves. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a top view illustrating an example of a configuration of a vehicle according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of a hardware configuration of the vehicle control system according to the embodiment. [Figure 3] FIG. 3 is a block diagram showing an example of the functional configuration of the object detection device according to this embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a transition of a vehicle state in this embodiment. [Figure 5A] FIG. 5A is a diagram showing an example of a random table when the vehicle state is the normal state in this embodiment. [Figure 5B]FIG. 5B is a diagram showing an example of a random table when the vehicle state is the first approach state in this embodiment. [Figure 5C] FIG. 5C is a diagram showing an example of a random table when the vehicle state is the second approach state in this embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of the procedure of the ultrasonic wave transmission process according to this embodiment. [Figure 7] FIG. 7 is a diagram showing an example of ultrasonic wave transmission timings shifted by random times in a conventional object detection device. [Figure 8] FIG. 8 is a diagram showing an example of ultrasonic wave transmission timings shifted by random times in a conventional object detection device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The configurations of the embodiments described below and the actions and effects brought about by the configurations are merely examples, and the present invention is not limited to the following description.

[0016] 1 is a top view showing an example of the configuration of a vehicle 1 according to an embodiment. The vehicle 1 is an example of a moving body on which an object detection device according to this embodiment is mounted. The object detection device according to this embodiment is a device that detects objects present around the vehicle 1 based on information such as TOF (Time Of Flight) and Doppler shift acquired by transmitting a transmission wave from the vehicle 1 and receiving a reception wave (reflected wave) generated when the transmission wave is reflected by an object.

[0017] The object detection device according to this embodiment is connected to a plurality of transceivers 21A to 21L. Hereinafter, when it is not necessary to distinguish between the plurality of transceivers 21A to 21L, they will be referred to as transceiver 21.

[0018] Each transceiver 21 is installed on the vehicle body 2, which is the exterior of the vehicle 1, and transmits ultrasonic waves (an example of a transmitted wave) toward the outside of the vehicle body 2, and receives reflected waves from objects outside the vehicle body 2 as received waves. In the example shown in Fig. 1, four transceivers 21A to 21D are arranged at the front end of the vehicle body 2, four transceivers 21E to 21H are arranged at the rear end, two transceivers 21I and 21J are arranged on the right side, and two transceivers 21K and 21L are arranged on the left side. Note that the number and installation locations of the transceivers 21 are not limited to this example.

[0019] 2 is a block diagram showing an example of a hardware configuration of a vehicle control system 50 according to an embodiment. The vehicle control system 50 performs processing for controlling the vehicle 1 based on information output from a transmission / reception unit 21. The vehicle control system 50 according to this embodiment mainly includes an ECU (Electronic Control Unit) 100, a plurality of transmission / reception units 21, a brake system 221, a buzzer 222, and an engine 223.

[0020] The ECU 100 and each transmitter / receiver 21 are connected by an in-vehicle network, LIN (Local Interconnect Network) 240. The ECU 100 is also connected by an in-vehicle network, CAN (Controller Area Network) 230, to each of the brake system 221, the buzzer 222, the engine 223, and the shift sensor 224.

[0021] Each transmitting / receiving unit 21 includes a vibrator 211 configured using a piezoelectric element or the like, an amplifier, etc., and realizes transmission and reception of ultrasonic waves by the vibration of the vibrator 211. Specifically, each transmitting / receiving unit 21 transmits ultrasonic waves generated in response to the vibration of the vibrator 211 as a transmission wave, and detects the vibration of the vibrator 211 caused by a reflected wave (received wave) of the transmission wave reflected by an object such as an obstacle O or a road surface RS. The vibration of the vibrator 211 is converted into an electrical signal, and based on the electrical signal, it is possible to obtain information such as a TOF corresponding to the distance from the transmitting / receiving unit 21 to the obstacle O and Doppler shift information corresponding to the relative speed of the obstacle O.

[0022] 2 illustrates a configuration in which both transmission of transmission waves and reception of reception waves are performed using a single oscillator 211, but the configuration of the transmitter / receiver 21 is not limited to this. For example, the transmitter and receiver may be separated, such as a configuration in which an oscillator for transmitting transmission waves and an oscillator for receiving reception waves are separately provided.

[0023] The ECU 100 is a unit that executes various processes for controlling the vehicle 1 based on various types of information. By sending control signals via the CAN 230, the ECU 100 can control the brake system 221, the engine 223, etc., and output sound to the buzzer 222. Furthermore, the ECU 100 can receive detection results from various sensors (not shown) via the CAN 230.

[0024] 2, the ECU 100 includes a CPU (Central Processing Unit) 130, an SSD (Solid State Drive) 121, a ROM (Read Only Memory) 122, and a RAM (Random Access Memory) 123. The ECU 100 is an example of an object detection device. The ECU 100 may also be referred to as an object detection device 100.

[0025] The CPU 130 can execute various types of arithmetic processing and control, such as outputting an alarm to the buzzer 222, detecting an object, and determining whether or not there is interference with an object. The ROM 122 is a non-volatile storage device. A program is stored in the ROM 122 in advance. The CPU 130 can read out the program stored in the ROM 122 and execute arithmetic processing in accordance with the program.

[0026] The RAM 123 temporarily stores various data used in the calculations of the CPU 130. The SSD 121 is a rewritable nonvolatile storage unit, and can store data even when the power of the ECU 100 is turned off. The CPU 130, ROM 122, RAM 123, etc. can be integrated in the same package. The ECU 100 may be configured to use other logic calculation processors, such as a DSP (Digital Signal Processor), logic circuits, etc., instead of the CPU 130. A HDD (Hard Disk Drive) may be provided instead of the SSD 121, or the SSD 121 and the HDD may be provided separately from the ECU 100.

[0027] The brake system 221 is, for example, an ABS (Anti-lock Brake System) that prevents the brakes from locking, an ESC (Electronic Stability Control) that prevents the vehicle 1 from skidding when cornering, an electric brake system that increases braking force (performing brake assist), or a BBW (Brake By Wire) system.

[0028] The engine 223 is a prime mover that drives the vehicle 1 . The buzzer 222 is provided inside the vehicle 1 and outputs an alarm.

[0029] Next, the functional configuration of the object detection device (ECU) 100 will be described. Fig. 3 is a block diagram showing an example of the functional configuration of the object detection device 100 according to this embodiment. As shown in Fig. 3, the object detection device 100 according to this embodiment has a functional configuration mainly including a sound wave control unit 150, a vehicle state estimation unit 160, a notification control unit 162, a vehicle information management unit 163, and a braking control unit 164.

[0030] The vehicle state estimation unit 160 estimates various states of the vehicle 1. In this embodiment, the state of the vehicle 1 is estimated to be one of a normal state, a first approach state, and a second approach state based on the distance to the object calculated by a detection distance calculation unit 1521 (described later). Details of the normal state, the first approach state, and the second approach state will be described later.

[0031] The notification control unit 162 issues a notification by outputting an alarm from the buzzer 222 when the vehicle 1 is approaching an object, that is, when the detection distance calculation unit 1521 (described later) determines that the distance to the object is equal to or shorter than a predetermined distance based on ultrasonic waves transmitted and received by the transmitter / receiver unit 21 (described later) by the abnormality detection unit 1522 (described later). The vehicle information management unit 163 manages various information about the vehicle 1. The braking control unit 164 controls braking by the brake system 221.

[0032] The ultrasonic wave control unit 150 controls the transmission of ultrasonic waves by the transmitting / receiving unit 21 and manages information based on the reflected waves received by the transmitting / receiving unit 21. As shown in FIG. 3, the ultrasonic wave control unit 150 includes a transmission / reception control unit 1510 and a transmission / reception information management unit 1520.

[0033] The transmission and reception control unit 1510 controls the transmission and reception of ultrasonic waves by the transmission and reception unit 21. The transmission and reception control unit 1510 includes a wave transmission control unit 1511, a random time determination unit 1512, and a random table 1513, as shown in FIG.

[0034] The wave transmission control unit 1511 controls the transmitting and receiving unit to transmit ultrasonic waves at a predetermined transmission timing. More specifically, the wave transmission control unit 1511 controls the transmitting and receiving unit 21 to transmit ultrasonic waves at new transmission timing obtained by delaying the transmission timing by a random time determined by a random time determination unit 1512 (described later). Here, the random time is a waiting time for shifting the transmission timing of the ultrasonic waves. The wave transmission control unit 1511 is an example of a control unit.

[0035] The random time determination unit 1512 determines the random time according to each of the normal state, the first approach state, and the second approach state as the state of the vehicle 1. The random time determination unit 1512 is an example of a determination unit.

[0036] Furthermore, the normal state is a state in which the distance to the object is greater than the first distance, or no object is detected. The first approach state is a state in which the distance to the object is equal to or less than the first distance. The second approach state is a state in which the distance is equal to or less than a second distance that is smaller than the first distance. In this embodiment, the vehicle state is classified into three states based on the distance to the object calculated by the detection distance calculation unit 1521, and the vehicle state transitions between these three states. In this embodiment, the first distance is set to 3 m and the second distance is set to 1 m, but the present invention is not limited to these.

[0037] FIG. 4 is a transition diagram of the vehicle state in this embodiment. When the vehicle state is in a normal state, if the distance to the detected object is the first distance of 3 m or less and is the same distance continuously (within 15 cm after movement distance correction), and if the vehicle has not transitioned to the first approach state in the last two times, the vehicle state will transition to the first approach state.

[0038] When the vehicle state is in a normal state and the distance to the detected object is the second distance of 1 m or less, the vehicle state transitions to the second approach state the first time it becomes 1 m or less. In other cases, the vehicle state does not transition from the normal state.

[0039] Furthermore, after the vehicle state transitions to the first approach state, it transitions to the normal state without transitioning to the second approach state. After the vehicle state transitions to the second approach state, it transitions to the normal state without transitioning to the first approach state.

[0040] That is, the random time determination unit 1512 determines the random time in the first approach state or the random time in the second approach state, and after the transmission wave control unit 1511 transmits the transmission wave at the new transmission timing, it determines the random time in the normal state.

[0041] Specifically, the random time determination unit 1512 refers to the random table 1513 and, depending on the state of the vehicle 1, determines different times for the random time of the ultrasonic waves as transmission waves from the transceiver units 21A to 21D provided at the front of the vehicle 1 and the random time of the ultrasonic waves from the transceiver units 21E to 21H provided at the rear of the vehicle 1.

[0042] Random table 1513 is stored in a storage medium such as SSD 121. Random table 1513 defines, for each vehicle state, i.e., normal state, first approach state, and second approach state, a random time (an example of a first random time) for the transmission waves from transceivers 21A to 21D provided at the front of vehicle 1 and a random time (an example of a second random time) for the transmission waves from transceivers 21E to 21H provided at the rear of vehicle 1.

[0043] 5A to 5C are diagrams showing examples of random tables according to this embodiment. Fig. 5A is a diagram showing an example of a random table in the normal state. Fig. 5B is a diagram showing an example of a random table in the first approach state. Fig. 5C is a diagram showing an example of a random table in the second approach state.

[0044] 5A to 5C, the random time for Fr (front) is the random time (first random time) of the transmission waves (i.e., ultrasonic waves) from the transmitting / receiving units 21A to 21D provided at the front of the vehicle 1, and the random time for Rr (rear) is the random time (second random time) of the transmission waves (i.e., ultrasonic waves) from the transmitting / receiving units 21E to 21H provided at the rear of the vehicle 1. Also, three random times are set for each, and any random time can be selected from these.

[0045] Here, the first distance is smaller than a distance based on a difference between a random time corresponding to the first approach state and a random time corresponding to the normal state, and the second distance is smaller than a distance based on a difference between a random time corresponding to the second approach state and a random time corresponding to the normal state.

[0046] In other words, a 1 ms delay in the transmission timing of the sound waves results in an estimation error of approximately 175 mm in distance. Note that this estimation error differs depending on the temperature. When the vehicle state transitions from the normal state to the first approach state or the second approach state and random table 1513 is changed, random time determination unit 1512 selects the minimum value in the random table so that the random time and the detection distances that are the transition conditions, i.e., the first distance and the second distance, satisfy the conditions of the following equations (1) and (2).

[0047] When transitioning from the normal state to the first approach state 175*(minimum random time of first approach state - maximum random time of normal state) >First distance...(1)

[0048] When transitioning from the normal state to the second approach state 175*(Minimum value of random time in the second approach state - Maximum value of random time in the normal state) >Second distance...(2)

[0049] That is, in this embodiment, since the first distance is 3 m, the random time is set to satisfy the above formula (1) in random table 1513 of the formulas in Figures 5A and 5B. Also, in this embodiment, since the second distance is 3 m, the random time is set to satisfy the above formula (2) in random table 1513 of the formulas in Figures 5A and 5C.

[0050] Then, as described above, after the vehicle state transitions to the first approach state, it transitions to the normal state without transitioning to the second approach state. After the vehicle state transitions to the second approach state, it transitions to the normal state without transitioning to the first approach state. That is, the random time determination unit 1512 determines the random time from the random table for the normal state. Therefore, when the vehicle transitions to the first approach state and then transitions to the normal state, the distance obtained by multiplying the difference between the random time for the first approach state and the random time for the normal state by 175 m becomes greater than the first distance, and ultrasonic waves are not transmitted for this distance, thereby making it possible to avoid interference with ultrasonic waves from other vehicles.

[0051] Similarly, when transitioning to the second approach state and then to the normal state, the distance obtained by multiplying the difference between the random time in the second approach state and the random time in the normal state by 175 m becomes greater than the second distance, and ultrasonic waves will not be transmitted for this distance, thereby avoiding interference with ultrasonic waves from other vehicles.

[0052] The transmission and reception information management unit 1520 manages information based on the reflected wave received by the transmission and reception unit 21. The transmission and reception information management unit 1520 includes a detection distance calculation unit 1521 and an abnormality detection unit 1522, as shown in FIG.

[0053] The detection distance calculation unit 1521 calculates the distance to an object based on the transmission wave transmitted by the transmission / reception unit 21 and the received reflected wave. Specifically, the detection distance calculation unit 1521 detects an object and calculates the distance to the object based on information such as TOF and Doppler shift acquired by receiving the reception wave (reflected wave) generated when the transmission wave is reflected by the object. Here, a known method is used to calculate the distance.

[0054] The abnormality detection unit 1522 detects abnormalities in the vehicle 1, etc. In this embodiment, the abnormality detection unit 1522 determines that an object is approaching when the distance calculated by the detection distance calculation unit 1521 is equal to or shorter than a predetermined distance. Furthermore, the abnormality detection unit 1522 detects whether or not ultrasonic waves are interfering based on the distance calculated by the detection distance calculation unit 1521. For example, when the abnormality detection unit 1522 detects that the distance calculated by the detection distance calculation unit 1521 is equal to or shorter than a predetermined threshold three times in succession, it determines that ultrasonic waves are interfering. Note that the method for detecting ultrasonic wave interference is not limited to this.

[0055] Next, the ultrasonic wave transmission process performed by the object detection device 100 according to this embodiment configured as above will be described. 6 is a flowchart showing an example of the procedure of the ultrasonic wave transmission process according to this embodiment. This transmission process is performed when the vehicle 1 starts traveling.

[0056] First, the random time determination unit 1512 acquires the distance to the object calculated by the detection distance calculation unit 1521 (S11). Then, the random time determination unit 1512 determines whether the acquired current distance is equal to or less than the second distance (S12). Here, the number of times the distance is equal to or less than the second distance is set to one. Then, if the distance is equal to or less than the second distance (S12: Yes), the vehicle state transitions to the second approach state, and the random time determination unit 1512 selects a random time from the random table 1513 for the second approach state shown in FIG. 5C (S13).

[0057] If the distance is greater than the second distance in S12 (S12: No), the random time determination unit 1512 determines whether the current distance is equal to or less than the first distance and is the same distance twice consecutively (S14). If the current distance is equal to or less than the first distance and is the same distance twice consecutively (S14: Yes), the vehicle state transitions to the first approach state, and the random time determination unit 1512 selects a random time from the random table 1513 for the first approach state shown in FIG. 5B (S15).

[0058] Then, the transmission control unit 1511 controls the transmission / reception unit 21 to transmit ultrasonic waves at timings shifted by the random time determined in S13 and S15, and as a result, the transmission / reception unit 21 transmits ultrasonic waves at timings shifted by the random time (S17).

[0059] Next, the vehicle state transitions to the normal state, and the random time determination unit 1512 selects a random time from the random table 1513 for the normal state shown in FIG. 5A (S18).

[0060] Then, the transmission control unit 1511 controls the transmission / reception unit 21 to transmit ultrasonic waves at timings shifted by the random time determined in S18, and as a result, the transmission / reception unit 21 transmits ultrasonic waves at timings shifted by the random time (S19).

[0061] Returning to S14, if the current distance is greater than the first distance, or if the current distance is less than the first distance but is not the same distance for two consecutive times (S14: No), the random time determination unit 1512 selects a random time from the normal state random table shown in Figure 5A (S16).

[0062] Then, the transmission control unit 1511 controls the transmission / reception unit 21 to transmit ultrasonic waves at timings shifted by the random time determined in S16, and as a result, the transmission / reception unit 21 transmits ultrasonic waves at timings shifted by the random time (S19).

[0063] Conventionally, a vehicle transmits ultrasonic waves to detect an object, and if the distance to the object is within a predetermined distance, a buzzer issues an alarm. However, if the timing of ultrasonic transmission between the vehicle and another vehicle is in a certain relationship, when the vehicle receives ultrasonic waves transmitted by the other vehicle, the ultrasonic waves may be mistakenly recognized as a reflected wave of the ultrasonic waves transmitted by the vehicle, resulting in interference. For example, if the vehicle and another vehicle simultaneously transmit ultrasonic waves, the vehicle may mistakenly recognize the ultrasonic waves returning from half the distance as a reflected wave. Therefore, if the object is in a short distance and is mistakenly recognized as being within the buzzer output range, the buzzer may be erroneously output.

[0064] Therefore, to avoid false recognition due to such interference, conventional object detection devices have a method of determining that interference is occurring if they detect the same distance continuously for more than a predetermined threshold. For example, an object detection device may determine that interference is occurring if it detects a distance of 30 cm three times in a row. If interference is determined to be occurring, the object detection device can avoid continuous detection of the same distance by shifting the timing of ultrasonic wave transmission.

[0065] 7 and 8 are diagrams showing an example of the transmission timing of ultrasonic waves shifted by a random time in a conventional object detection device. As shown in Fig. 7, for example, if ultrasonic waves are transmitted at intervals of 168 ms and interference is determined, the object detection device can avoid the interference by transmitting ultrasonic waves every 172 ms, which is a random shift of 4 ms.

[0066] However, when a vehicle receives ultrasonic waves from another vehicle, the other vehicle often also receives ultrasonic waves from the vehicle. Consider a case where two vehicles are equipped with an object detection device that uses the same method as the conventional interference avoidance processing. In this case, even if the object detection device detects interference and shifts the transmission timing of the ultrasonic waves of the vehicle, if the other vehicle also shifts its transmission timing using the same method, the transmission timings may again coincide, causing interference, as shown in Figure 8.

[0067] In contrast, in this embodiment, the random time determination unit 1512 determines a random time, which is a waiting time for shifting the transmission timing, in accordance with each of a normal state in which the distance to the object is greater than a first distance or no object is detected, a first approach state in which the distance to the object is equal to or less than the first distance, and a second approach state in which the distance to the object is equal to or less than a second distance that is smaller than the first distance, and the wave transmission control unit 1511 controls the transceiver unit 21 to transmit a transmission wave at a new transmission timing that is delayed by the determined random time. Therefore, according to this embodiment, even if another vehicle is equipped with the same object detection device as the host vehicle, the random time is delayed in accordance with the state of the vehicle 1, making it possible to reliably avoid ultrasonic interference.

[0068] Furthermore, in this embodiment, the first distance is smaller than the distance based on the difference between the random time corresponding to the first approach state and the random time corresponding to the normal state, and the second distance is smaller than the distance based on the difference between the random time corresponding to the second approach state and the random time corresponding to the normal state. After the wave transmission control unit 1511 transmits a transmission wave at a new transmission timing in the first approach state or the second approach state, the random time determination unit 1512 determines the random time corresponding to the normal state. Therefore, by transitioning from the first approach state or the second approach state to the normal state, the distance corresponding to the difference in the random times becomes larger than the first distance as a transition condition for transitioning from the normal state to the first approach state and the second distance as a transition condition for transitioning from the normal state to the second approach state. Therefore, according to this embodiment, even if the other vehicle is equipped with the same object detection device as the host vehicle, the possibility of interference with the other vehicle is reduced by this difference in distance, making it possible to more reliably avoid interference.

[0069] Furthermore, in this embodiment, the random time determination unit 1512 determines different times for the random times of the transmission waves from the transceivers 21A to 21D provided at the front of the vehicle 1 and the random times of the transmission waves from the transceivers 21E to 21H provided at the rear of the vehicle 1. Therefore, according to this embodiment, even if another vehicle is equipped with the same object detection device as the vehicle itself, it is possible to reliably avoid interference of ultrasonic waves depending on the traveling direction of the vehicle 1.

[0070] Furthermore, this embodiment further includes an SSD 121 that stores a random table 1513 in which random times are determined corresponding to the normal state, the first approach state, and the second approach state, and the random time determination unit 1512 determines the random time based on the normal state, the first approach state, and the second approach state and the random table 1513. Therefore, according to this embodiment, the random time can be determined by switching the random table, so that even if another vehicle is equipped with the same object detection device as the host vehicle, ultrasonic interference can be avoided simply and more reliably.

[0071] In the above-described embodiment, the CPU 130 reads and executes programs stored in a storage device such as the ROM 122 or the SSD 121, thereby realizing various functional modules such as the wave transmission control unit 1511, the random time determination unit 1512, the detection distance calculation unit 1521, the abnormality detection unit 1522, the vehicle state estimation unit 160, the notification control unit 162, the vehicle information management unit 163, and the braking control unit 164. However, this is not limited to this. For example, the various functional modules such as the wave transmission control unit 1511, the random time determination unit 1512, the detection distance calculation unit 1521, the abnormality detection unit 1522, the vehicle state estimation unit 160, the notification control unit 162, the vehicle information management unit 163, and the braking control unit 164 can also be realized by independent hardware.

[0072] The object detection program executed by the object detection device 100 of the above embodiment is provided in a state that it is pre-installed in a ROM or the like.

[0073] The object detection program executed by the object detection device 100 of the above embodiment may be configured to be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk).

[0074] Furthermore, the object detection program executed by object detection device 100 of the above embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Also, the object detection program executed by object detection device 100 of the above embodiment may be provided or distributed via a network such as the Internet.

[0075] The object detection program executed by the object detection device 100 of the above embodiment has a modular structure including the above-mentioned units (wave transmission control unit 1511, random time determination unit 1512, detection distance calculation unit 1521, abnormality detection unit 1522, vehicle state estimation unit 160, notification control unit 162, vehicle information management unit 163, braking control unit 164, etc.), and in terms of actual hardware, the CPU reads and executes the object detection program from the above-mentioned ROM, thereby loading the above-mentioned units onto the main memory, and the wave transmission control unit 1511, random time determination unit 1512, detection distance calculation unit 1521, abnormality detection unit 1522, vehicle state estimation unit 160, notification control unit 162, vehicle information management unit 163, braking control unit 164, etc. are generated on the main memory.

[0076] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0077] 1 vehicle 21 Transmitter / receiver 50 Vehicle Control System 100 Object detection unit (ECU) 121 SSD 211 Oscillator 150 Sonic control unit 1510 Transmission and reception control section 1511 Transmission control section 1512 Random Time Determination Unit 1513 Random Table 1520 Transmission and Reception Information Management Department 1521 Detection distance calculation unit 1522 Anomaly detection unit 160 Vehicle state estimation unit 162 Notification control section 163 Vehicle Information Management Department 164 Braking control unit

Claims

1. An object detection device that is mounted on a vehicle and detects objects present around the vehicle, a control unit that controls a transceiver unit that transmits a transmission wave and receives a reception wave generated when the transmission wave is reflected by the object, to transmit the transmission wave at a predetermined transmission timing; a distance calculation unit that calculates a distance to the object based on the transmitted wave and the received wave; a determination unit that determines a random time, which is a waiting time for shifting the transmission timing, in accordance with each of a normal state in which the distance to the object is greater than a first distance or the object is not detected, a first approach state in which the distance to the object is equal to or less than the first distance, and a second approach state in which the distance to the object is equal to or less than a second distance that is smaller than the first distance, the control unit controls the transceiver unit to transmit the transmission wave at a new transmission timing obtained by delaying the transmission timing by the determined random time. Object detection device.

2. the first distance is smaller than a distance based on a difference between the random time corresponding to the first approach state and the random time corresponding to the normal state, and the second distance is smaller than a distance based on a difference between the random time corresponding to the second approach state and the random time corresponding to the normal state, the determination unit determines the random time according to the normal state after the control unit transmits the transmission wave at the new transmission timing in the first approach state or the second approach state. The object detection device according to claim 1 .

3. the determination unit determines the random time of the transmission wave from the transceiver unit provided in the front part of the vehicle to be different from the random time of the transmission wave from the transceiver unit provided in the rear part of the vehicle. The object detection device according to claim 2 .

4. a storage unit that stores random information in which a random time is determined corresponding to each of the normal state, the first approach state, and the second approach state, the determination unit determines the random time based on the normal state, the first approach state, the second approach state, and the random information. The object detection device according to claim 1 .

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