JP6965577B2 - Object detection device - Google Patents

Description

The present invention relates to an object detection device.

A technique is known in which a detection wave such as an ultrasonic wave is transmitted to an object and the detection wave reflected by the object is received to measure the distance to the object. Further, there is known a technique of measuring the height of a vehicle or the like by transmitting a detection wave downward and receiving a detection wave reflected on the ground.

Japanese Unexamined Patent Publication No. 2016-112929 Japanese Unexamined Patent Publication No. 2010-145363

However, in the above-mentioned technique, since it is necessary to separately provide a device for detecting an object and a device for measuring the height, there is a problem that the configuration of the device becomes complicated.

The present invention has been made in view of the above, and an object of the present invention is to provide an object detection device capable of simplifying the configuration.

In order to solve the above-mentioned problems and achieve the object, the object detection device of the present invention is provided in a vehicle, and includes a plurality of transmission / reception units that transmit the detection wave and receive the reflected detection wave. The control unit that controls the transmission / reception unit and calculates the transmission / reception time, which is the time between the time when the detection wave is transmitted and the time when the detection wave is received, and the distance to the object are calculated based on the transmission / reception time of the detection wave. A processing unit that calculates the vehicle height based on the vehicle height transmission / reception time, which is the transmission / reception time of the detection wave within the preset vehicle height determination time , is provided, and the processing unit includes a plurality of the transmission / reception units. A plurality of vehicle heights are calculated based on the transmission / reception time of each unit, and when any of the plurality of vehicle heights is an abnormal value, the vehicle height of the abnormal value is calculated by the vehicle height other than the abnormal value. At the time of correction, the inclination of the vehicle is adjusted based on preset vehicle mounting position information of the transmission / reception unit and a plurality of vehicle heights calculated based on the detection waves received by the plurality of transmission / reception units. Calculate and correct the vehicle height of the abnormal value based on the inclination of the vehicle.

In the object detection device of the present invention, the processing unit that calculates the distance to the object based on the transmission / reception time of the detection wave calculates the vehicle height based on the transmission / reception time within the vehicle height determination time. As a result, the object detection device can calculate the vehicle height and the distance to the object with one device, so that the configuration of the device can be simplified. Further, when the processing unit includes an abnormal value in the vehicle height, the processing unit corrects the vehicle height of the abnormal value by a plurality of vehicle heights other than the abnormal value, so that more accurate calculation of the vehicle height can be realized. At this time, since the processing unit corrects the abnormal value of the vehicle height based on the vehicle inclination and the vehicle mounting position information calculated from the plurality of vehicle heights, the vehicle height is more accurate according to the position of the transmission / reception unit. Correction can be realized.

The object detection device of the present invention is provided in a vehicle, transmits a detection wave, controls a plurality of transmission / reception units for receiving the reflected detection wave, and controls the transmission / reception unit, and the time when the detection wave is transmitted. The control unit that calculates the transmission / reception time, which is the time between the reception time and the reception time, and the distance to the object based on the transmission / reception time of the detection wave, and within the preset vehicle height determination time The processing unit includes a processing unit that calculates the vehicle height based on the transmission / reception time for the vehicle height, which is the transmission / reception time of the detection wave, and the processing unit has a plurality of vehicle heights based on the transmission / reception time of each of the plurality of transmission / reception units. When any of the plurality of vehicle heights is an abnormal value, when the vehicle height of the abnormal value is corrected by the vehicle height other than the abnormal value, the vehicle height of the abnormal value is said to be the same. The vehicle height of the abnormal value is based on a linear function that is a function of the vehicle height calculated from the transmission / reception time of the transmission / reception units adjacent to each other on both sides of the transmission / reception unit that transmits / receives the detection wave and the position of the transmission / reception unit. To correct.

As described above, in the object detection device of the present invention, the processing unit that calculates the distance to the object based on the transmission / reception time of the detection wave calculates the vehicle height based on the transmission / reception time within the vehicle height determination time. .. As a result, the object detection device can calculate the vehicle height and the distance to the object with one device, so that the configuration of the device can be simplified. Further, when the processing unit includes an abnormal value in the vehicle height, the processing unit corrects the vehicle height of the abnormal value by a plurality of vehicle heights other than the abnormal value, so that more accurate calculation of the vehicle height can be realized. At this time, since the processing unit corrects the vehicle height of the abnormal value based on the linear function which is a function of the vehicle height and the position of the transmission / reception unit, the vehicle height is corrected with higher accuracy according to the position of the transmission / reception unit. Can be realized.

The object detection device of the present invention is provided in a vehicle, transmits a detection wave, controls a transmission / reception unit that receives the reflected detection wave, and controls the transmission / reception unit, and receives the time and reception of the detection wave. The detection wave within the preset vehicle height determination time by calculating the distance to the object based on the transmission / reception time of the detection wave and the control unit that calculates the transmission / reception time, which is the time between the time and the time. The processing unit includes a processing unit that calculates the vehicle height based on the vehicle height transmission / reception time, which is the transmission / reception time of the vehicle height. If the difference between the reception level of the peak and the reception level of the peak of the detection wave of the other transmission / reception unit is equal to or greater than the level difference threshold, the object is based on the peak equal to or greater than the level difference threshold. Calculate the distance to .

As described above, in the object detection device of the present invention, the processing unit that calculates the distance to the object based on the transmission / reception time of the detection wave calculates the vehicle height based on the transmission / reception time within the vehicle height determination time. .. As a result, the object detection device can calculate the vehicle height and the distance to the object with one device, so that the configuration of the device can be simplified. At this time, the processing unit can calculate the distance of the object existing at a distance substantially the same as the vehicle height.

In the object detection device of the present invention, the frequency of the detection wave transmitted by the transmission / reception unit is higher than the vehicle height frequency for measuring the vehicle height and the distance to the object. A frequency switching unit for switching between the frequency for measuring the distance and the frequency for measuring the distance may be further provided.

As described above, in the object detection device of the present invention, when calculating the vehicle height, the frequency switching unit transmits the detection wave of the vehicle height frequency having a low frequency and wide directivity to the transmission / reception unit, so that the detection wave is transmitted from the ground. The reception level of the detection wave can be made relatively high. Further, when calculating the distance to the object, the frequency switching unit transmits the detection wave of the high frequency and narrow directivity frequency to the transmission / reception unit, so that the reception level of the detection wave from the object is relatively high. Can be made larger. As a result, the object detection device can improve the accuracy of calculating the vehicle height and the distance to the object.

If the reception level of the peak of the detection wave within the vehicle height determination time is equal to or higher than the determination threshold value, the processing unit of the object detection device of the present invention is the distance to the object based on the peak. May be calculated.

As a result, the processing unit of the object detection device of the present invention can calculate the distance of the object existing at a distance substantially the same as the vehicle height.

FIG. 1 is a plan view showing the vehicle of the first embodiment. FIG. 2 is a block diagram illustrating a configuration of a control system mounted on the vehicle of the first embodiment. FIG. 3 is a functional block diagram illustrating the function of the object detection device of the first embodiment. FIG. 4 is a diagram for explaining the calculation of the vehicle height and the distance to the object by the vehicle height calculation unit and the distance calculation unit. FIG. 5 is a flowchart of the measurement process of the first embodiment executed by the object detection device. FIG. 6 is a functional block diagram illustrating the function of the object detection device of the second embodiment. FIG. 7 is a graph showing the reception level of the detection wave of the distance frequency of the second embodiment. FIG. 8 is a flowchart of the measurement process of the second embodiment executed by the control unit of each transmission / reception device. FIG. 9 is a graph illustrating a method of calculating the distance to the object by the distance calculation unit of the third embodiment.

Similar components such as the following exemplary embodiments are given common reference numerals, and duplicate description will be omitted as appropriate.

<First Embodiment>
FIG. 1 is a plan view showing the vehicle 10 of the first embodiment. As shown in FIG. 1, the vehicle 10 includes a vehicle body 12, a plurality of (for example, 4) wheels 13, and 1 or a plurality (for example, 4) imaging units 14a, 14b, 14c, 14d, 1 or It has a plurality of (for example, eight) transmission / reception devices 16Fa, 16Fb, 16Fc, 16Fd, 16Fe, 16Ff, 16Ba, 16Bb, 16Bc, 16Bd, 16Be, 16Bf. When it is not necessary to distinguish the imaging units 14a, 14b, 14c, and 14d, it is referred to as the imaging unit 14. When it is not necessary to distinguish between the transmission / reception device 16F and the transmission / reception device 16Bf, the transmission / reception device 16 is described.

The vehicle body 12 constitutes a passenger compartment in which an occupant rides. The vehicle body 12 accommodates or holds the configuration of the vehicle 10 such as the wheels 13, the image pickup unit 14, and the transmission / reception device 16.

The image pickup unit 14 is, for example, a digital camera incorporating an image pickup element such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor). The image pickup unit 14 outputs the data of the captured image obtained by capturing the periphery of the vehicle 10. The imaging unit 14 is provided around the vehicle body 12. For example, the image pickup unit 14a is provided at a central portion (for example, a front bumper) in the left-right direction of the front end portion of the vehicle body 12. The imaging unit 14a generates an captured image of the periphery in front of the vehicle 10. The image pickup unit 14b is provided at a central portion (for example, a rear bumper) in the left-right direction of the rear end portion of the vehicle body 12. The imaging unit 14b generates an captured image of the rear periphery of the vehicle 10. The imaging unit 14c is provided at the center of the left end of the vehicle body 12 in the front-rear direction (for example, the left side mirror 12a). The imaging unit 14c generates an captured image of the left periphery of the vehicle 10. The imaging unit 14d is provided at the center of the right end of the vehicle body 12 in the front-rear direction (for example, the right side mirror 12b). The imaging unit 14d generates an image captured by capturing the right periphery of the vehicle 10.

The transmission / reception device 16 is provided in the vehicle 10 (for example, around the vehicle 10). The transmission / reception device 16 transmits a detection wave to the ground or an object, and receives the detection wave reflected by the ground or an object. For example, the transmission / reception devices 16Fa to 16Fc are provided at different positions on the left side of the front end portion of the vehicle body 12. Therefore, the transmission / reception devices 16F to 16Fc transmit / receive detection waves for measuring the distances to the objects on the left front and left sides of the vehicle 10 and the vehicle height at the left front end of the vehicle 10. The transmission / reception devices 16Fd to 16Ff are provided at different positions on the right side of the front end portion of the vehicle body 12. Therefore, the transmission / reception devices 16Fd to 16Ff transmit / receive detection waves for measuring the distances to the objects on the right front and right sides of the vehicle 10 and the vehicle height at the right front end of the vehicle 10. The transmission / reception devices 16Ba to 16Bc are provided at different positions on the left side of the rear end portion of the vehicle body 12. Therefore, the transmission / reception devices 16Ba to 16Bc transmit / receive detection waves for measuring the distances to the objects on the left rear and left sides of the vehicle 10 and the vehicle height at the left rear end of the vehicle 10. The transmission / reception devices 16Bd to 16Bf are provided at different positions on the right side of the rear end portion of the vehicle body 12. Therefore, the transmission / reception devices 16Bd to 16Bf transmit / receive detection waves for measuring the distances to the objects on the right rear and right sides of the vehicle 10 and the vehicle height at the right rear end of the vehicle 10. When the transmission / reception device 16 receives the detection wave, the transmission / reception device 16 calculates the transmission / reception time, which is the time between the transmission and reception of the detection wave. The transmission / reception time is also called TOF (= Time Of Fright).

FIG. 2 is a block diagram illustrating a configuration of a control system mounted on the vehicle 10 of the first embodiment. As shown in FIG. 2, the vehicle 10 further includes an object detection device 20, a monitor device 34, and an in-vehicle network 38.

The object detection device 20 measures the distance to an object existing around the vehicle 10 by transmitting and receiving detection such as ultrasonic waves, and also measures the vehicle height, which is the height of the vehicle 10. The object detection device 20 includes a transmission / reception device 16 and an information processing device 36.

The information processing device 36 is a computer including a microcomputer such as an ECU (Electronic Control Unit). The information processing device 36 acquires the data of the captured image from the imaging unit 14. The information processing device 36 transmits data related to an image or sound generated based on an captured image or the like to a monitor device 34. The information processing device 36 calculates the distance to the object and the vehicle height based on the transmission / reception time acquired from the transmission / reception device 16.

The information processing unit 36 includes a CPU (Central Processing Unit) 36a, a ROM (Read Only Memory) 36b, a RAM (Random Access Memory) 36c, a display control unit 36d, a voice control unit 36e, and an SSD (Solid State Drive). ) 36f and the like. The CPU 36a, ROM 36b and RAM 36c may be integrated in the same package.

The CPU 36a is an example of a hardware processor, reads a program stored in a non-volatile storage device such as a ROM 36b, and executes various arithmetic processes and controls according to the program. The CPU 36a executes, for example, a measurement process for calculating the distance to the object and the vehicle height.

The ROM 36b stores each program and parameters required for executing the program. The RAM 36c temporarily stores various data used in the calculation by the CPU 36a. The display control unit 36d mainly executes image processing of the image obtained by the imaging unit 14, data conversion of the image for display to be displayed on the display unit 40, and the like among the arithmetic processing in the information processing device 36. The voice control unit 36e mainly executes the voice processing to be output to the voice output unit 42 among the arithmetic processing in the information processing device 36. The SSD 36f is a rewritable non-volatile storage unit, and maintains data even when the power of the information processing device 36 is turned off.

In the present embodiment, the information processing device 36 executes a measurement process for calculating the distance to the object and the vehicle height by the cooperation of the hardware and the software (program).

The monitoring device 34 is provided on a dashboard or the like in the vehicle interior. The monitoring device 34 includes a display unit 40, an audio output unit 42, and an operation input unit 44.

The display unit 40 displays an image based on the image data transmitted by the information processing device 36. The display unit 40 is, for example, a display device such as a liquid crystal display (LCD) or an organic EL display (OLELD). The display unit 40 displays, for example, an image of the surroundings of the vehicle 10 captured by the image pickup unit 14.

The voice output unit 42 outputs voice based on the voice data transmitted by the information processing device 36. The audio output unit 42 is, for example, a speaker. The audio output unit 42 may be provided at a position in the vehicle interior different from that of the display unit 40.

The operation input unit 44 receives the input of the occupant. The operation input unit 44 is, for example, a touch panel, a push button type hard switch, or the like. The operation input unit 44 is provided on the display screen of the display unit 40. The operation input unit 44 is configured to be transparent to the image displayed by the display unit 40. As a result, the operation input unit 44 can make the occupant visually recognize the image displayed on the display screen of the display unit 40. The operation input unit 44 receives the instruction input by the occupant touching the position corresponding to the image displayed on the display screen of the display unit 40, and transmits the instruction to the information processing device 36.

The in-vehicle network 38 includes, for example, CAN (Controller Area Network) and LIN (Local Interconnect Network). The in-vehicle network 38 electrically connects the transmission / reception device 16, the information processing device 36, and the operation input unit 44 so as to be able to transmit and receive signals and information to each other. In addition, for example, the transmission / reception device 16, the information processing device 36, and the operation input unit 44 may be directly connected to each other by LIN (Local Interconnect Network) or the like.

FIG. 3 is a functional block diagram illustrating the function of the object detection device 20 of the first embodiment. As shown in FIG. 3, each of the plurality of transmission / reception devices 16 has a transmission / reception unit 46, a control unit 48, and a sub-storage unit 50.

The transmission / reception unit 46 is provided in the vehicle 10 to transmit a detection wave to the ground or an object, and also receives a detection wave reflected by the ground or an object. The transmission / reception unit 46 is, for example, a sonar having a piezoelectric element or the like and transmitting / receiving a detection wave such as a sound wave including an ultrasonic wave. The transmission / reception unit 46 transmits the detection wave in a substantially horizontal direction, and receives the detection wave reflected by an object or the like existing around the vehicle 10. Here, the transmission / reception unit 46 transmits a detection wave having a wide directivity that can travel not only in the horizontal direction, which is the direction in which the detection wave is transmitted, but also in the vertical direction. For example, the transmission / reception unit 46 transmits a detection wave having a wide directivity that travels in a direction inclined by 90 ° or more with respect to a direction in which the detection wave is transmitted (that is, a substantially horizontal direction). The transmission / reception unit 46 transmits a detection wave having a low frequency (for example, 40 kHz to 70 kHz) or a detection wave having a large side lobe as a detection wave having a wide directivity. Therefore, the transmission / reception unit 46 receives the detection wave reflected by the object existing in the horizontal direction and the detection wave reflected by the ground below. The transmission / reception unit 46 outputs a reception level indicating the intensity of the received detection wave to the control unit 48.

The control unit 48 may be, for example, a circuit such as an IC (Integrated Circuit). The control unit 48 controls the transmission / reception unit 46 to calculate the transmission / reception time, which is the time between the transmission of the detection wave and the reception of the detection wave.

Specifically, the control unit 48 outputs a transmission signal to the transmission / reception unit 46 to transmit the detection wave. The control unit 48 calculates the transmission time, which is the time when the transmission / reception unit 46 transmits the detection wave. The time when the detection wave is transmitted may be the time when the transmission of the detection wave is started. For example, the control unit 48 may calculate the transmission time based on the time when the transmission signal is output to the transmission / reception unit 46 and the transmission delay time set in advance. Specifically, the control unit 48 may calculate the time obtained by adding the transmission delay time to the time when the transmission signal is output as the transmission time. The transmission delay time is, for example, the time required from the time when the control unit 48 outputs the transmission signal to the time when the transmission / reception unit 46 starts transmitting the detection wave. The transmission delay time may be measured in advance and stored as a part of the numerical data 51 of the sub-storage unit 50.

The control unit 48 sequentially acquires the reception level of the detection wave from the transmission / reception unit 46 that has received the detection wave reflected by the ground, an object, or the like. The control unit 48 calculates the reception time, which is the time when the detection wave is received. The time when the detection wave is received is, for example, the time when the transmission / reception unit 46 starts receiving the waveform of the detection wave that has temporarily peaked. The peak referred to here may be limited to the level threshold value or higher. The level threshold value may be predetermined and stored as a part of the numerical data 51 of the sub-storage unit 50.

The control unit 48 calculates the transmission / reception time, which is the time between the transmission of the detection wave and the reception of the detection wave, from the difference between the transmission time and the reception time for each peak of the reception level sequentially acquired in time series. Therefore, when there are a plurality of peaks, the control unit 48 calculates a plurality of transmission / reception times while receiving one detection wave. The control unit 48 outputs the calculated one or more transmission / reception times to the information processing device 36. The control unit 48 may output the transmission / reception time and the peak reception level to the information processing device 36 in association with each other.

The sub-storage unit 50 is, for example, a rewritable storage device such as an EEPROM (Erasable and Programmable Read-Only Memory) or an EEPROM (Electrically Erasable and Programmable Read-Only Memory). The sub-storage unit 50 stores the transmission delay time required for the control unit 48 to process the calculation of the transmission / reception time, the numerical data 51 such as the level threshold value, and the like.

As shown in FIG. 3, the information processing device 36 has a processing unit 52 and a main storage unit 54.

The processing unit 52 is realized, for example, as a function of the CPU 36a. The processing unit 52 may be a hardware processor other than the CPU 36a. The processing unit 52 includes a vehicle height calculation unit 58 and a distance calculation unit 59. The processing unit 52 may realize the functions of the vehicle height calculation unit 58 and the distance calculation unit 59 by reading the measurement program 60 stored in the main storage unit 54. A part or all of the vehicle height calculation unit 58 and the distance calculation unit 59 may be configured by hardware such as a circuit including an ASIC (Application Specific Integrated Circuit).

The vehicle height calculation unit 58 calculates the vehicle height based on the vehicle height transmission / reception time acquired from each of the control units 48 of the plurality of transmission / reception devices 16. The vehicle height transmission / reception time is the transmission / reception time of the detection wave within the vehicle height determination time among the transmission / reception times of the detection waves acquired from the control unit 48. The vehicle height determination time is included in the determination data 62 that is predetermined and stored in the main storage unit 54. Here, the vehicle height calculation unit 58 calculates the vehicle height based on the transmission / reception time of each of the control units 48 of the plurality of transmission / reception devices 16, so that a plurality of vehicle heights are calculated as a result.

The vehicle height calculation unit 58 determines whether or not an abnormal value is included in the plurality of vehicle heights calculated based on each of the detection waves received by the plurality of transmission / reception units 46. When any of the plurality of vehicle heights is an abnormal value, the vehicle height calculation unit 58 corrects the vehicle height of the abnormal value with a vehicle height other than the abnormal value. For example, the vehicle height calculation unit 58 is calculated based on each of the vehicle mounting position information 63 of the transmission / reception unit 46 preset and stored in the main storage unit 54 and the detection waves received by the plurality of transmission / reception units 46. The inclination of the vehicle 10 may be calculated based on the vehicle height of the vehicle 10, and the vehicle height of an abnormal value may be corrected based on the inclination of the vehicle 10. The vehicle mounting position information 63 is information indicating the position of the transmission / reception device 16 in the vehicle 10.

The vehicle height calculation unit 58 uses the calculated vehicle heights to perform corrections and the like for other devices. For example, the vehicle height calculation unit 58 adjusts the optical axis of the image pickup unit 14 based on the calculated vehicle height to set an adjustment value for correcting the captured image.

The distance calculation unit 59 calculates the distance to the object based on the transmission / reception time acquired from each of the control units 48 of the plurality of transmission / reception devices 16. The distance calculation unit 59 calculates the distance to the object based on the transmission / reception time other than the vehicle height transmission / reception time (hereinafter referred to as the distance transmission / reception time) used by the vehicle height calculation unit 58 to calculate the vehicle height. You can. Here, the distance calculation unit 59 calculates the distance to the object based on the distance transmission / reception time acquired from each of the control units 48 of the plurality of transmission / reception devices 16, and as a result, a plurality of distances in a plurality of directions are calculated. The distance to the object will be calculated.

The main storage unit 54 is realized, for example, as a function of the ROM 36b, the RAM 36c, and the SSD 36f. The main storage unit 54 may be provided externally and connected via a network. The main storage unit 54 stores the program executed by the processing unit 52 and the information necessary for executing the program. For example, the main storage unit 54 stores the measurement program 60 executed by the processing unit 52. The main storage unit 54 stores the determination data 62 and the vehicle mounting position information 63 necessary for the processing unit 52 to execute the measurement program 60. The determination data 62 includes a vehicle height determination time for calculating the vehicle height and the like.

FIG. 4 is a diagram illustrating a method of calculating the vehicle height and the distance to the object by the vehicle height calculation unit 58 and the distance calculation unit 59. In FIG. 4, the horizontal axis represents the time and the vertical axis represents the reception level of the detection wave. The thin solid line indicates the reception level RL acquired by the control unit 48. Although the reception level RL is indicated by a continuous line, it may be a discontinuous value. The thick dotted line indicates the level threshold Th1 indicated by the determination data 62. The level threshold Th1 may be a discontinuous value.

The control unit 48 outputs a transmission signal to the transmission / reception unit 46 to calculate the transmission time at which the transmission level of the detection wave is maximized. In FIG. 4, the transmission time is the origin on the horizontal axis.

The control unit 48 acquires the reception level RL of the reflected detection wave from the transmission / reception unit 46 in chronological order, and sets the peak times PT1, PT2, and PT3 at which the reception level RL of the detection wave reaches the peak of the level threshold Th1 or higher. To detect. When it is not necessary to distinguish the peak time PT1, PT2, and PT3, it is described as the peak time PT.

The control unit 48 calculates the transmission / reception time, which is the time between the transmission of the detection wave and the reception of the detection wave, from the difference between the transmission time and the reception time for each peak of the reception level sequentially acquired in time series. In FIG. 4, since the transmission time is “0”, the reception time is the transmission / reception time.

The vehicle height calculation unit 58 and the distance calculation unit 59 calculate the vehicle height and the distance to the object based on the transmission / reception time and the vehicle height determination time.

In FIG. 4, the vehicle height determination time is the time from the time T1a to the time T1b, and is the time for calculating the vehicle height. The time T1b is set, for example, in association with the maximum value of the vehicle height. The maximum vehicle height is, for example, the vehicle height when nothing is loaded on the vehicle 10. The time T1a is set, for example, longer than the time at which the vibration of the piezoelectric element due to the transmission of the detection wave almost ends, and is associated with the minimum value of the vehicle height. The minimum vehicle height is, for example, the vehicle height in a state where a load having a maximum load capacity is applied to the vehicle 10. Therefore, the minimum value of the vehicle height is also a value obtained by subtracting the sinking amount of the vehicle 10 when the load of the maximum load capacity is applied to the vehicle 10 from the maximum value of the vehicle height. An example of the amount of sinking of the vehicle 10 is several cm to several tens of cm. The transmission / reception time corresponding to the maximum amount of sinking is "dT".

The vehicle height calculation unit 58 calculates the vehicle height based on the vehicle height transmission / reception time within the vehicle height determination time among the transmission / reception times calculated by the control unit 48. Specifically, the vehicle height calculation unit 58 calculates 1/2 of the product of the vehicle height transmission / reception time and the speed of the detection wave as the vehicle height. When the detection wave is an ultrasonic wave, the speed of the detection wave is the speed of sound.

The distance calculation unit 59 calculates the distance to the object based on the transmission / reception time for distance, which is the transmission / reception time other than the transmission / reception time for vehicle height, among the transmission / reception times calculated by the control unit 48. Specifically, the distance calculation unit 59 calculates 1/2 of the product of the transmission / reception time for distance and the speed of the detection wave as the distance to each object.

FIG. 5 is a flowchart of the measurement process of the first embodiment executed by the object detection device 20. The left side of FIG. 5 is a flowchart executed by the control unit 48 of each transmission / reception device 16. The right side of FIG. 5 is a flowchart executed by the processing unit 52 of the information processing apparatus 36. The processing unit 52 executes the measurement processing of the first embodiment by reading the measurement program 60 stored in the main storage unit 54 when the vehicle 10 is started.

As shown in FIG. 5, in the measurement process of the first embodiment, the control unit 48 of each transmission / reception device 16 outputs a transmission signal to the transmission / reception unit 46 (S1102). As a result, the transmission / reception unit 46 that has acquired the transmission signal transmits the detection wave.

The control unit 48 acquires the reception level RL from the transmission / reception unit 46 that has transmitted the detection wave (S1104). The control unit 48 determines whether or not the reception of the detection wave is completed (S1106). For example, the control unit 48 may determine that the reception of the detection wave has been completed when a predetermined time has elapsed since the transmission signal was output. Further, the control unit 48 may determine that the reception of the detection wave is completed when the acquisition of the reception level RL from the transmission / reception unit 46 is completed. The control unit 48 repeats step S1104 and subsequent steps until it is determined that the reception of the detection wave is completed (S1106: No), and sequentially acquires the reception level RL in chronological order.

When the control unit 48 determines that the reception of the detection wave is completed (S1106: Yes), the control unit 48 calculates the transmission / reception time for each peak of the acquired reception level RL (S1108), and associates it with its own identification information to receive the reception level RL. And the transmission / reception time is output to the information processing device 36 (S1110).

In the processing unit 52 of the information processing device 36, the vehicle height calculation unit 58 and the distance calculation unit 59 acquire the transmission / reception time from the control unit 48 of the transmission / reception device 16 (S2102). The vehicle height calculation unit 58 calculates the vehicle height based on the vehicle height transmission / reception time, which is the transmission / reception time within the vehicle height determination time, and the speed of the detection wave among the acquired transmission / reception times (S2104). The distance calculation unit 59 is based on the distance transmission / reception time and the detection wave speed, which are the transmission / reception times outside the vehicle height determination time (that is, the transmission / reception time other than the vehicle height transmission / reception time) among the acquired transmission / reception times. , Calculate the distance to the object (S2106).

The distance calculation unit 59 determines whether or not the calculation of the distance to the object based on the transmission / reception time for all distances has been completed (S2108). When the distance calculation unit 59 determines that the calculation of the distances to all the objects has not been completed (S2108: No), the distance calculation unit 59 repeats step S2106.

Next, when the distance calculation unit 59 determines that the calculation of the distances to all the objects has been completed (S2108: Yes), the vehicle height calculation unit 58 and the distance calculation unit 59 all of the transmission / reception devices 16. It is determined whether or not the processes of steps S2104 to S2108 have been executed with respect to the transmission / reception time (S2110). The vehicle height calculation unit 58 and the distance calculation unit 59 execute the processes of steps S2104 to S2108 for each of the transmission / reception devices 16 until it is determined that the processing has been executed for all the transmission / reception devices 16. Calculate the heights of a plurality of vehicles and the distances to a plurality of objects (S2110: No).

When the vehicle height calculation unit 58 and the distance calculation unit 59 determine that the processes of steps S2104 to S2108 have been executed for all the transmission / reception devices 16 (S2110: Yes), the vehicle height calculation unit 58 has a plurality of vehicles. It is determined whether any of the high values is an abnormal value (S2112). For example, the vehicle height calculation unit 58 sets the absolute value of the difference between one of the calculated vehicle heights and the average value of the other plurality of vehicle heights to be greater than a preset vehicle height difference threshold. If it is large, it may be determined that the vehicle height is an abnormal value. When it is determined that all the vehicle heights are not abnormal values (S2112: No), the vehicle height calculation unit 58 executes step S2116.

When the vehicle height calculation unit 58 determines that any of the vehicle heights is an abnormal value (S2112: Yes), the vehicle height calculation unit 58 corrects the vehicle height determined to be an abnormal value (S2114). For example, the vehicle height calculation unit 58 calculates the inclination of the vehicle 10 from a plurality of vehicle heights that are not abnormal values calculated based on the detection waves of the plurality of transmission / reception devices 16. The vehicle height calculation unit 58 may correct an abnormal vehicle height based on the calculated inclination of the vehicle 10. For example, when the vehicle height calculation unit 58 determines that the vehicle height calculated from the detection wave of the transmission / reception device 16Fd is an abnormal value, it calculates from the detection waves of the transmission / reception device 16Fa and the transmission / reception device 16Fe adjacent to each other on both sides of the transmission / reception device 16Fd. The vehicle height at the position of the transmission / reception device 16Fd is corrected based on the inclination of the vehicle 10 calculated from the two vehicle heights and the position of the transmission / reception device 16Fd indicated by the vehicle mounting position information 63.

The vehicle height calculation unit 58 executes the corrected vehicle height utilization process (S2116). For example, the vehicle height calculation unit 58 calculates the inclination of the vehicle 10 and the like based on the vehicle height, adjusts the optical axis of the image pickup unit 14, and calculates an adjustment value for correcting the captured image. As a result, the processing unit 52 ends the measurement process.

As described above, in the object detection device 20, the vehicle height calculation unit 58 and the distance calculation unit 59 calculate the vehicle height and the distance to the object based on the vehicle height determination time. As a result, the vehicle height calculation unit 58 can accurately calculate the vehicle height based on the vehicle height transmission / reception time within the vehicle height determination time. Further, the distance calculation unit 59 can accurately calculate the distance to the object based on the transmission / reception time for the distance other than the determination time for the vehicle height. As a result, the object detection device 20 can calculate the vehicle height and the distance to the object with one device, so that the configuration of the device can be simplified.

In the object detection device 20, the vehicle height calculation unit 58 calculates the vehicle height for each of the detection waves received by the plurality of transmission / reception devices 16. As a result, the vehicle height calculation unit 58 can determine whether or not the plurality of vehicle heights include an abnormal value based on the calculated plurality of vehicle heights. Further, when the vehicle height includes an abnormal value, the vehicle height calculation unit 58 can correct the vehicle height of the abnormal value by a plurality of other vehicle heights. As a result, the object detection device 20 can realize more accurate calculation of the vehicle height.

In the vehicle height correction, the vehicle height calculation unit 58 determines that the vehicle height is an abnormal value based on the inclination of the vehicle 10 calculated from the plurality of vehicle heights that is not an abnormal value calculated from the vehicle height transmission / reception times of the plurality of transmission / reception devices 16. Correct the vehicle height. As a result, the vehicle height calculation unit 58 can realize more accurate vehicle height correction according to the position of the transmission / reception device 16.

<Second Embodiment>
FIG. 6 is a functional block diagram illustrating the function of the object detection device 120 of the second embodiment. As shown in FIG. 6, the transmission / reception devices 116Ba to 116Bf and 116Fa to 116Ff of the object detection device 120 of the second embodiment further include a frequency switching unit 70, respectively. The arrangement of the transmission / reception devices 116Ba to 116Bf and 116F to 116Ff is the same as the arrangement of the transmission / reception devices 16Ba to 16Bf and 16Fa to 16Ff. When it is not necessary to distinguish between the transmission / reception devices 116Ba to 116Bf and 116F to 116Ff, the transmission / reception device 116 is described. Each frequency switching unit 70 is connected to one of the transmission / reception units 46 and the control unit 148.

The control unit 148 outputs the vehicle height transmission signal, which is a transmission signal for calculating the vehicle height, and the distance transmission signal, which is a transmission signal for calculating the distance to the object, to the frequency switching unit 70 at different timings. For example, the control unit 148 outputs a vehicle height transmission signal when the vehicle 10 is started. The control unit 148 outputs a vehicle height transmission signal, the vehicle height calculation unit 58 calculates the vehicle height, and then outputs a distance transmission signal.

The frequency switching unit 70 switches the frequency of the detection wave transmitted by the transmission / reception unit 46 based on the transmission signal from the control unit 148. Specifically, when the frequency switching unit 70 acquires the vehicle height transmission signal from the control unit 148, the frequency switching unit 70 causes the transmission / reception unit 46 to transmit a vehicle height frequency detection wave for measuring the vehicle height. When the frequency switching unit 70 acquires the distance transmission signal from the control unit 148, the frequency switching unit 70 causes the transmission / reception unit 46 to transmit a detection wave of the distance frequency for measuring the distance to the object. That is, the frequency switching unit 70 switches the frequency of the detection wave transmitted by the transmission / reception unit 46 between the vehicle height frequency and the distance frequency. Here, the frequency for distance is higher than the frequency for vehicle height. For example, the frequency for distance may be about 20% to 30% higher than the frequency for vehicle height. Therefore, the directivity of the detection wave of the vehicle height frequency is wider than the directivity of the detection wave of the distance frequency. The detection wave of the vehicle height frequency may be the same as the detection wave of the first embodiment, for example.

The vehicle height calculation unit 58 and the distance calculation unit 59 determine the vehicle height and the vehicle height based on the transmission / reception time of the detection wave, the reception level of the detection wave, and the vehicle height determination time included in the determination data 62 stored in the main storage unit 54. Calculate the distance to the object.

FIG. 7 is a graph showing the reception level RL in the detection wave of the distance frequency of the second embodiment. In FIG. 7, the horizontal axis represents the time and the vertical axis represents the reception level of the detection wave.

The detection wave of the distance frequency has a narrower directivity than the detection wave of the vehicle height frequency, and the rate of traveling downward is small. Therefore, as shown in FIG. 7, the peak of the time PT1 for calculating the vehicle height is It becomes smaller. Further, since the distance frequency is higher than the vehicle height frequency, the detection wave of the distance frequency has a larger attenuation rate than the detection wave of the vehicle height frequency. Therefore, the reception level of the detection wave of the distance frequency is generally smaller than the reception level of the detection wave of the vehicle height frequency. Therefore, the level threshold Th2 for the detection wave of the distance frequency may be smaller than the level threshold Th1 for the detection wave of the vehicle height frequency.

The time T1a and time T1b that define the vehicle height determination time at the distance frequency may be the same as the corresponding times T1a and T1b at the vehicle height frequency.

FIG. 8 is a flowchart of the measurement process of the second embodiment executed by the control unit 148 of each transmission / reception device 116. The process executed by the processing unit 52 of the information processing device 36 is almost the same as that of the first embodiment, and thus is omitted. Regarding the processing of the second embodiment similar to the control unit 48 of the first embodiment, the same step number is assigned to simplify the description.

As shown in FIG. 8, in the measurement process of the second embodiment, the control unit 148 of each transmission / reception device 116 outputs the vehicle height transmission signal to the frequency switching unit 70 (S1202). As a result, the frequency switching unit 70 that has acquired the vehicle height transmission signal causes the transmission / reception unit 46 to transmit the detection wave of the vehicle height frequency.

Next, the control unit 148 calculates the transmission / reception time for calculating the vehicle height based on the detection wave of the vehicle height frequency received by the transmission / reception unit 46, and outputs the transmission / reception time to the information processing device 36 (S1104 to S1110). .. The transmission / reception time may include at least the transmission / reception time for vehicle height, and may include the transmission / reception time for distance.

When the control unit 148 finishes the process related to the vehicle height, the control unit 148 outputs a distance transmission signal (S1203). As a result, the frequency switching unit 70 that has acquired the distance transmission signal causes the transmission / reception unit 46 to transmit the detection wave of the distance frequency.

The control unit 148 executes steps S1204 to S1210, which are almost the same processes as steps S1104 to S1110, with respect to the detection wave of the distance frequency received by the transmission / reception unit 46, and calculates the distance to the object. The transmission / reception time for this is calculated and output to the information processing apparatus 36 (S1204 to S1210).

The control unit 148 determines whether or not the vehicle 10 has stopped (S1222). When the control unit 148 determines that the vehicle 10 is not stopped (S1222: No), the control unit 148 outputs a distance transmission signal to the transmission / reception unit 46 (S1203), and repeats steps S1204 and subsequent steps. As a result, the control unit 148 outputs a distance transmission signal to the transmission / reception unit 46 until the vehicle 10 stops, and determines the distance to the object based on the detection wave of the distance frequency transmitted by the transmission / reception unit 46. Calculate the transmission / reception time for calculation. The transmission / reception time may include at least the transmission / reception time for distance, and may include the transmission / reception time for vehicle height.

When the control unit 148 determines that the vehicle 10 has stopped (S1222: Yes), the control unit 148 ends the process.

As described above, in the object detection device 120, the frequency switching unit 70 switches the frequency of the detection wave transmitted by the transmission / reception device 116 between the vehicle height frequency and the distance frequency higher than the vehicle height frequency for detection. The directivity of the wave can be switched. For example, when calculating the vehicle height, the object detection device 120 widens the directivity by a detection wave having a vehicle height frequency lower than the distance frequency. As a result, when calculating the vehicle height, the object detection device 120 can increase the ratio of the reception level RL of the detection wave reflected by the ground to the reception level RL of the detection wave reflected by the object. On the other hand, when calculating the distance to the object, the object detection device 120 narrows the directivity by the detection wave of the distance frequency higher than the vehicle height frequency. As a result, when calculating the distance to the object, the object detection device 120 can increase the ratio of the reception level RL of the detection wave reflected by the object to the reception level of the detection wave reflected by the ground. ..

Therefore, when calculating the vehicle height, the object detection device 120 can improve the calculation accuracy of the vehicle height by the detection wave having a high reception level RL reflected by the ground. Further, when calculating the distance to the object, the object detection device 120 can improve the calculation accuracy of the distance to the object by the detection wave having a high reception level RL reflected by the object.

<Third Embodiment>
Next, a third embodiment in which the distance calculation method of the distance calculation unit 59 is partially modified will be described. FIG. 9 is a graph illustrating a method of calculating the distance to the object by the distance calculation unit 59 of the third embodiment. Each configuration of the third embodiment will be described with reference numerals of each configuration of the first embodiment.

As shown in FIG. 9, when the object exists at a distance substantially the same as the vehicle height, the transmission / reception unit 46 receives both the detection wave reflected by the ground and the detection wave reflected by the object, so that the vehicle height determination is made. The peak in time (here, the peak at time PT1) becomes larger than the peak of the detection wave (see the dotted line) when the object does not exist.

The distance calculation unit 59 of the third embodiment is an object existing at a distance substantially the same as the vehicle height based on the peak transmission / reception time and the reception level RL within the vehicle height determination time acquired from the control unit 48 of the transmission / reception device 16. The distance to the object may be calculated. Specifically, if the reception level of the peak of the detection wave within the vehicle height determination time is equal to or higher than the preset determination threshold Th3, the distance calculation unit 59 determines the object based on the transmission / reception time of the peak. You may calculate the distance to. As a result, the object detection device 20 of the third embodiment can calculate the distance of the object existing at a distance substantially the same as the vehicle height. The determination threshold Th3 is preferably larger than the level threshold Th1 and higher than the reception level of only reflection from the ground.

Further, within the vehicle height determination time, the difference between the peak of the detection wave in which the object does not exist and the peak of the detection wave in the case where the object exists becomes large, so that the distance calculation unit 59 is based on the difference. Therefore, it may be determined whether or not the object exists at a distance substantially the same as the vehicle height. Specifically, the distance calculation unit 59 includes the reception level RL of the peak of the detection wave received by the transmission / reception unit 46 of any transmission / reception device 16 within the vehicle height determination time, and the transmission / reception unit 46 of the other transmission / reception device 16. Calculates the level difference, which is the difference between the peak of the detection wave received by and the reception level RL. If the level difference is equal to or greater than a predetermined level difference threshold value, the distance calculation unit 59 determines that the object exists at a distance substantially the same as the vehicle height, and is equal to or greater than the level difference threshold value within the vehicle height determination time. The distance to the object may be calculated based on the transmission / reception time of the peak of the detection wave. As a result, the object detection device 20 of the third embodiment can calculate the distance of the object existing at a distance substantially the same as the vehicle height.

The functions, connection relationships, numbers, arrangements, etc. of the configurations of the above-described embodiments may be appropriately changed or deleted within the scope of the invention and the scope equivalent to the scope of the invention. Each embodiment may be combined as appropriate. The order of each step of each embodiment may be changed as appropriate.

In the above-described embodiment, the example of 12 transmission / reception devices 16 has been described, but the number of transmission / reception devices 16 may be changed as appropriate.

In the above-described embodiment, the vehicle height calculation unit 58 gives an example of correcting an abnormal vehicle height based on the inclination of the vehicle 10 calculated from a plurality of vehicle heights, but the vehicle height correction is not limited to this. .. For example, the vehicle height calculation unit 58 calculates the vehicle height and the position of the transmission / reception device 16 from the transmission / reception time of the detection waves received by the transmission / reception devices 16 adjacent to each other on both sides of the transmission / reception device 16 that transmits / receives the detection wave of the abnormal value vehicle height. The vehicle height of an abnormal value may be corrected based on a linear function which is a function of. For example, when the vehicle height calculation unit 58 determines that the vehicle height calculated from the detection wave of the transmission / reception device 16Fd is an abnormal value, the vehicle height calculation unit 58 together with the two vehicle heights calculated from the detection waves of the transmission / reception device 16Fa and the transmission / reception device 16Fe, and transmission / reception. A linear function indicating the relationship between the positions of the device 16Fa and the transmission / reception device 16Fe is calculated. The vehicle height calculation unit 58 corrects the vehicle height obtained by substituting the position of the transmission / reception device 16Fd into the linear function as the vehicle height at the position of the transmission / reception device 16Fd. As a result, the vehicle height calculation unit 58 can realize more accurate vehicle height correction according to the position of the transmission / reception device 16Fd that causes the abnormal value of the vehicle height.

The transmission / reception device 16 may have an amplifier (that is, an amplifier) that amplifies the reception level RL. In this case, the transmission / reception device 16 may amplify the reception level RL by an amplifier so that the reception level RL that decreases as the distance of the object increases becomes constant.

In the above-described embodiment, the threshold value function in which the threshold value is locally uneven has been described as an example, but the present invention is not limited to this. For example, in the threshold function, the threshold value may gradually decrease as the transmission / reception time increases.

In the above-described embodiment, the control units 48 and 148 are provided in the transmission / reception devices 16 and 116, but the present invention is not limited to this. For example, the control units 48 and 148 may be provided in the processing unit 52 of the information processing device 36. In this case, the control units 48 and 148 may acquire the transmission time of the detection wave and the reception level indicating the intensity of the received detection wave from the transmission / reception devices 16 and 116 in chronological order to calculate the transmission / reception time.

In the above-described embodiment, an example in which the time T1a and the time T1b that define the vehicle height determination time are set is given, but the present invention is not limited to this. For example, a plurality of sets of time T1a to time T1b that define the vehicle height determination time may be preset in association with the temperature at which the sound velocity is changed.

In the first embodiment described above, the level threshold Th1 gives one example, but the present invention is not limited to this. For example, a plurality of level threshold values Th1 may be set in advance in association with the humidity that changes the level of the detection wave. Specifically, the higher the humidity, the lower the level threshold Th1 may be. Similarly, a plurality of level threshold values Th2 and determination threshold value Th3 may be set in advance in association with the humidity that changes the level of the detection wave.

10 ... Vehicle 46 ... Transmission / reception unit 20, 120 ... Object detection device 52 ... Processing unit 48, 148 ... Control unit 58 ... Vehicle height calculation unit 59 ... Distance calculation unit 70 ... Frequency switching unit RL ... Reception level

Claims (5)

A plurality of transmission / reception units provided in the vehicle to transmit the detection wave and receive the reflected detection wave.
A control unit that controls the transmission / reception unit and calculates the transmission / reception time, which is the time between the time when the detection wave is transmitted and the time when the detection wave is received.
The distance to the object is calculated based on the transmission / reception time of the detection wave, and the vehicle height is calculated based on the vehicle height transmission / reception time, which is the transmission / reception time of the detection wave within the preset vehicle height determination time. Processing unit and
With
The processing unit calculates a plurality of vehicle heights based on the transmission / reception time of each of the plurality of transmission / reception units, and when any of the plurality of vehicle heights is an abnormal value, the vehicle height other than the abnormal value is obtained. When correcting the vehicle height of the abnormal value, the vehicle mounting position information of the transmission / reception unit set in advance and the plurality of vehicle heights calculated based on the detection waves received by the plurality of transmission / reception units are used. An object detection device that calculates the inclination of the vehicle based on the above and corrects the vehicle height of the abnormal value based on the inclination of the vehicle. A plurality of transmission / reception units provided in the vehicle to transmit the detection wave and receive the reflected detection wave.
A control unit that controls the transmission / reception unit and calculates the transmission / reception time, which is the time between the time when the detection wave is transmitted and the time when the detection wave is received.
The distance to the object is calculated based on the transmission / reception time of the detection wave, and the vehicle height is calculated based on the vehicle height transmission / reception time, which is the transmission / reception time of the detection wave within the preset vehicle height determination time. Processing unit and
With
The processing unit calculates a plurality of vehicle heights based on the transmission / reception time of each of the plurality of transmission / reception units, and when any of the plurality of vehicle heights is an abnormal value, the vehicle height other than the abnormal value is obtained. When correcting the vehicle height of the abnormal value, the vehicle height calculated from the transmission / reception time of the transmission / reception units adjacent to both sides of the transmission / reception unit that transmitted / received the detection wave of the vehicle height of the abnormal value. An object detection device that corrects the vehicle height of the abnormal value based on a linear function that is a function of the position of the transmission / reception unit. A transmitter / receiver provided in the vehicle that transmits the detection wave and receives the reflected detection wave.
A control unit that controls the transmission / reception unit and calculates the transmission / reception time, which is the time between the time when the detection wave is transmitted and the time when the detection wave is received.
The distance to the object is calculated based on the transmission / reception time of the detection wave, and the vehicle height is calculated based on the vehicle height transmission / reception time, which is the transmission / reception time of the detection wave within the preset vehicle height determination time. Processing unit and
With
The processing unit has a reception level of the peak of the detection wave of any of the plurality of transmission / reception units within the vehicle height determination time and the reception level of the peak of the detection wave of the other transmission / reception unit. An object detection device that calculates the distance to the object based on the peak above the level difference threshold if the difference is equal to or greater than the level difference threshold. The frequency of the detection wave transmitted by the transmission / reception unit is switched between a vehicle height frequency for measuring the vehicle height and a distance frequency for measuring the distance to the object higher than the vehicle height frequency. The object detection device according to any one of claims 1 to 3 , further comprising a frequency switching unit. If the reception level of the peak of the detection wave within the vehicle height determination time is equal to or higher than the determination threshold value, the processing unit calculates the distance to the object based on the peak, claims 1 to 4. The object detection device according to any one of the above items.

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