CN112166344B

CN112166344B - Detection device

Info

Publication number: CN112166344B
Application number: CN201980034007.6A
Authority: CN
Inventors: 和智勇介; 中村宝弘
Original assignee: Hitachi Astemo Ltd
Current assignee: Hitachi Astemo Ltd
Priority date: 2018-06-28
Filing date: 2019-05-09
Publication date: 2023-07-28
Anticipated expiration: 2039-05-09
Also published as: JP6981928B2; WO2020003759A1; JP2020003351A; CN112166344A

Abstract

The invention provides a detection device. In the detection device (1), a transmitting antenna (TXANT 1) spatially transmits a modulated signal. The receiving antennas (RXANT 1 to RXANTN) receive reflected waves of the modulated signals transmitted from the transmitting antenna (TXANT 1). The calculation unit is provided with distance peak detection units (31-3N) and an azimuth detection unit (34), obtains the distance and azimuth of the object from the received signals of the reflected waves received by the receiving antennas (RXANT 1-RXANT) at regular intervals, and calculates the time variation of the distance from the obtained distance and azimuth of the object. A corner detection unit (35) detects the corners of the object on the basis of the time-varying amounts calculated by the calculation unit. The corner detection unit compares the time variation calculated by the calculation unit with a preset threshold value, detects a corner of the object when the time variation exceeds the threshold value, and outputs a corner detection signal.

Description

Detection device

Technical Field

The present invention relates to a detection device, and more particularly to a technique effective for detecting a corner portion in an object by a radar system.

Background

As a technique of reducing the load of a driver driving a motor vehicle and reducing the accident rate, a driving assistance system is attracting attention. As one of the driving support systems, there is an automatic parking support system.

The automatic parking assist system is a system that detects a parking space while maintaining an appropriate distance from an adjacent vehicle at a target parking position, guides the vehicle into a separation line, and automatically parks a motor vehicle.

In recent years, with the improvement of performance of millimeter wave radar, application of millimeter wave radar is advancing not only for long-distance detection originally used but also for medium-distance or short-distance detection, and millimeter wave radar is used for a detection device for detecting a corner portion or the like of a target vehicle in automatic parking for the purpose of realizing automatic parking application.

As a detection technique using a detection device of such a radar device, for example, in order to prevent erroneous grouping processing in which a reflection point group across a plurality of objects is determined to be 1 object or the like when detecting an object in front of the host vehicle with a millimeter wave radar, it is known to calculate right-end identification points, left-end identification points, and representative identification points of the plurality of reflection points, and perform grouping processing using estimated widths of the objects calculated based on the respective variations (for example, refer to patent document 1).

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2015-132553

Disclosure of Invention

Problems to be solved by the invention

However, in the technique of patent document 1, although it is determined whether or not the target object is the same object using the time variation of the identification points, no method is described for calculating the right and left identification points, which are the corners of the object.

In addition, when vertical parking or lateral parking is performed by automatic parking, it is necessary to quickly and accurately extract the corner portions of the target vehicle. In the case of patent document 1, the right end identification point is a reflection point located at the rightmost end in the left-right direction among reflection points within the group range, but it is impossible to determine whether or not there is a corner of the object. In other words, the corner portion of the target vehicle cannot be detected, and there is a risk that the accuracy of automatic parking is lowered.

In addition, as a technique of detecting a corner portion or the like in a target vehicle using the above-described millimeter wave radar, it is conceivable to detect a corner portion of the target vehicle by performing beam scanning with transmit beam forming of the millimeter wave radar.

However, in this case, a phase shifter or the like for performing transmit beamforming is newly required, and the number of transmit antennas increases. As a result, there is a problem that the cost of the detection device increases.

The present invention aims to provide a technique capable of detecting corners of an object rapidly and inexpensively in an automatic parking application.

The above and other objects and novel features of the present invention will be made apparent from the accompanying drawings and description of the present invention.

Means for solving the problems

The outline of a representative invention among the inventions disclosed in the present application will be briefly described as follows.

That is, a representative detection device has a 1 st transmitting antenna, a plurality of receiving antennas, a calculation section, and a corner detection section. The 1 st transmitting antenna transmits a modulated signal to space. The plurality of receiving antennas receive reflected waves of the modulated signal transmitted from the 1 st transmitting antenna.

The calculation unit obtains the distance and azimuth of the object from the received signals of the reflected waves received by the plurality of receiving antennas at regular intervals, and calculates the time variation of the distance from the obtained distance and azimuth of the object.

The corner detection unit detects a corner of the object based on the time-varying amount calculated by the calculation unit. The corner detection unit compares the time variation calculated by the calculation unit with a preset threshold value, detects a corner of the object when the time variation exceeds the threshold value, and outputs a corner detection signal indicating that the corner of the object is detected.

In particular, the corner detection unit detects, as a corner of the object, a point of the object corresponding to the distance and the azimuth calculated by the calculation unit before the time when the time variation exceeds the threshold value.

ADVANTAGEOUS EFFECTS OF INVENTION

The effects obtained by the representative invention among the inventions disclosed in the present application will be briefly described as follows.

It is possible to provide a detection device which is low in cost and short in detection time.

Drawings

Fig. 1 is an explanatory diagram showing an example of the structure of the detection device according to embodiment 1.

Fig. 2 is an explanatory diagram illustrating an operation performed by the detection device of fig. 1.

Fig. 3 is a flowchart showing an example of operation processing performed by the detection device of fig. 1.

Fig. 4 is an explanatory diagram of a strong reflection signal of an object, a signal intensity of a reflection point located between the strong reflection point and a corner of the object, and an azimuth.

Fig. 5 is an explanatory view showing another example of the detection device of fig. 1.

Fig. 6 is a flowchart showing an example of the detection process performed by the detection device of fig. 5.

Fig. 7 is an explanatory diagram showing an example of a verification experiment for each scene of the vertical automatic parking obtained by the study of the present inventors.

Fig. 8 is an explanatory diagram showing an example of the reception intensity in the millimeter wave radar having the wide-angle antenna for BSD application, which has been studied by the present inventors.

Fig. 9 is an explanatory diagram of FFT spectra in the verification experiment of fig. 8.

Fig. 10 is an explanatory diagram showing a relationship between the amount of spectral leakage power of the reflected signal and the reflected signal intensity.

Fig. 11 is an explanatory diagram showing an example of the structure of the detection device according to embodiment 2.

Fig. 12 is an explanatory view of an operation performed by the detection device of fig. 11.

Fig. 13 is a flowchart showing an example of detection processing performed by the detection device of fig. 11.

Fig. 14 is a flowchart showing an example of detection processing when a new switch and a new transmitting antenna are provided in the detection device of fig. 11.

Fig. 15 is an explanatory diagram showing an example of the structure of the detection device according to embodiment 3.

Fig. 16 is an explanatory diagram of an operation in the detection device of fig. 15.

Fig. 17 is an explanatory diagram showing a relationship between the distance and the azimuth angle at each time of the distance positions R0 and R4 between the host vehicle and the target vehicle.

Fig. 18 is a flowchart showing an example of the detection process performed by the detection device of fig. 15.

Fig. 19 is a flowchart showing an example of detection processing when a new switch and a new transmitting antenna are provided in the detection device of fig. 15.

Fig. 20 is an explanatory diagram showing an example of the structure of the detection device according to embodiment 4.

Fig. 21 is a flowchart showing an example of the detection process performed by the detection device of fig. 20.

Detailed Description

In all the drawings for explaining the embodiments, the same members are denoted by the same reference numerals in principle, and repeated descriptions thereof are omitted.

(embodiment 1)

The embodiments are described in detail below.

Structure example of detection device

Fig. 1 is an explanatory diagram showing an example of the structure of the detection device 1 according to embodiment 1.

As shown in fig. 1, the detection device 1 includes a transmitting/receiving antenna/analog unit 2, a digital signal processing unit 3, and a memory 4. The transmitting/receiving antenna/analog section 2 has a frequency generator VCO, a transmitting antenna TXANT1, N receiving antennas RXANT1 to RXANT constituting N receiving channels, N mixers MIX1 to MIX, and N analog/digital converters ADC1 to ADCN. The reception antennas RXANT1 to RXANTN are arranged at intervals at which a phase difference occurs in the reception signals between the reception channels in order to detect the azimuth of the object.

The modulated signals generated by the frequency generator VCO are distributed to the transmit antenna TXANT1 and the mixers MIX1 to MIX, respectively. The modulated signal is, for example, a signal in the 79GHz band in millimeter wave radar.

The 1 st transmission antenna TXANT1 transmits the modulated signal output from the frequency generator VCO as electromagnetic waves to space. The emitted electromagnetic wave hits the object, and a part of the reflected electromagnetic wave is received by the receiving antennas RXANT1 to RXANTN of the detection device 1.

The reception signals received by the reception antennas RXANT1 to RXANT n are converted into low-frequency signals by the mixers MIX1 to MIX, and are sent to the analog/digital converters ADC1 to ADCN.

The low-frequency signal converted by the mixers MIX1 to MIX includes a frequency component corresponding to the distance between the detection device 1 and the object. The low-frequency signals are converted into digital signals by the analog/digital converters ADC1 to ADCN, respectively, and then sent to the digital signal processing unit 3.

The digital signal processing unit 3 includes distance peak detection units 31 to 3N, an azimuth detection unit 34, and a corner detection unit 35. The distance peak detecting units 31 to 3N constituting the calculating unit convert signals converted into digital signals by the analog/digital converters ADC1 to ADCN of the transmitting/receiving antenna/analog unit 2 from time domain signals to frequency domain signals by, for example, FFT (fast fourier transform: fast Fourier Transform) processing.

Then, power intensity and phase information at a frequency proportional to the distance from the object to the detection device 1 are extracted from the converted frequency domain signal, and the extracted power intensity and phase information at the frequency are output to the azimuth detection unit 34.

The azimuth detecting unit 34 constituting the calculating unit detects the azimuth in which the object exists by using, for example, signal processing of DBF (Digital Beam Forming: digital beam forming) based on the power intensity and phase information at the frequencies generated by the distance peak detecting units 31 to 3N, and outputs the information of the distance and azimuth of the object to the memory 4 and the corner detecting unit 35, respectively.

The memory 4 stores information of the distance and the orientation of the object output from the orientation detection unit 34 for each time period t=t1 to t=tn, and outputs the information of the distance and the orientation of the object for each time period to the corner detection unit 35. Here, N of time t=tn is different from the number N of the above-described reception channels.

The corner detection unit 35 determines whether or not there is a corner of the object based on the information of the distance and the azimuth of the object output from the azimuth detection unit 34 and the information of the distance/azimuth of the object at each time stored in the memory 4, and outputs a corner detection signal when the corner of the object is detected.

< principle of operation of detection device 1 >

Here, the operation of the detection device 1 will be described.

Fig. 7 is an explanatory diagram showing an example of a verification experiment for each scene of the vertical automatic parking obtained by the study of the present inventors. Fig. 8 is an explanatory diagram showing an example of the reception intensity in the millimeter wave radar having the wide-angle antenna for BSD (Blind Spot Detection) application, which has been studied by the present inventors.

First, the inventors have conducted a verification experiment for each scene of longitudinal automatic parking shown in fig. 7 in order to realize an automatic parking application using a millimeter wave radar.

Fig. 7 shows an example in which a wall 105 is provided on the left side, a curb 106 is provided on the right side, and a vehicle 101 and a vehicle 102 are longitudinally parked along the curb 106 with a parking space corresponding to 1 vehicle, so that the vehicle 100 is automatically parked between the vehicle 101 and the vehicle 102.

In fig. 7, in a state where automatic parking is started, the host vehicle 100 needs to accurately and promptly recognize the rear corner of the vehicle 101, which is the target vehicle parked in front.

For example, in the case where the side portion of the target vehicle 101 is observed with a millimeter wave radar having an antenna with a wide angle, a signal from a distance position R0 where the emitted electromagnetic wave is perpendicularly incident to the target vehicle 101 is strongly received as shown by a solid line in fig. 8. On the other hand, signals from the distance positions R1 to R5, which are incident from angles other than the normal, are specularly reflected as shown by the broken lines in fig. 8, and the reception intensity is lowered.

In particular, the sharper the incident angle is, the stronger the specular reflection is, and the reception power is extremely small at the corner of the target vehicle 101 to be detected, that is, at the distance position R5 shown in fig. 8, and if the corner of the target vehicle 101 approaches the distance position R0 without the host vehicle 100 backing up, the detection is difficult.

As shown in the FFT spectrum of fig. 9, the received signal from the distance position R0 having strong reflection intensity also affects the received signals from the distance positions R1 to R5 due to spectrum leakage caused by the window function at the time of the FFT processing, making it more difficult to detect the corners of the target vehicle 101. The distance intervals between the distance positions R0 to R1 and the distance positions R1 to R2, … … are determined by the resolving power of the FFT.

As described above with reference to fig. 9, the received signal from the distance position R0 having strong reflection intensity also affects the received signals from the distance positions R1 to R5 due to spectral leakage caused by the window function at the time of FFT processing.

However, as a result of the detailed study, the present inventors have found that, at a distance between a distance position R0 where the reflection intensity is strong and a distance position where a corner of the target vehicle 101 exists, there is a signal at a distance position which is not masked by the spectral leakage power at the distance position R0 and which is larger than the noise floor.

Fig. 10 is an explanatory diagram showing a relationship between the amount of spectral leakage power of the reflected signal and the reflected signal intensity. Fig. 10 shows the comparison result of the amount of spectral leakage power with respect to the reflected signal from the distance position R0 in fig. 8 and the reflected signal intensity from the distance position R4.

The spectral leakage power from the distance position R0 decreases as the distance bin becomes farther away, and the direction detection by DBF becomes smaller than the spectral leakage power from the distance position R0 by about 10dB at the distance bin from the distance position R4, and it is confirmed that the direction from the distance position R4 can be detected. The detection technique in the detection device 1 is based on this conclusion.

Operation example of detection device 1

The operation of the detection device 1 will be described in detail below.

Fig. 2 is an explanatory diagram illustrating an operation performed by the detection device 1 of fig. 1. Fig. 3 is a flowchart showing an example of the operation processing performed by the detection device 1 of fig. 1. The flowchart shown in fig. 3 shows a process mainly performed by the digital signal processing unit 3 included in the detection device 1.

First, at time t=t1 shown in fig. 2, the automatic parking process by the vehicle 100 is started. At this time t=t1, the detection device 1 transmits, in other words, emits, electromagnetic waves to the target vehicle 101, and receives reflected waves from the target vehicle 101 by the reception antennas RXANT1 to RXANT of the detection device 1.

The received reception signal is frequency-converted and converted into a digital signal by the transmitting/receiving antenna/analog section 2 of the detecting apparatus 1, and is output to the digital signal processing section 3. The digital signal is subjected to FFT processing by the distance peak detection units 31 to 3N of the digital signal processing unit 3, and frequency proportional to the distance from the object to the detection device 1 and power intensity and phase information at the frequency are extracted. The power intensity and phase information at the frequency is output to the azimuth detection unit 34.

The azimuth detecting unit 34 obtains information on the distance and azimuth of the distance position R0 where the reflection intensity is strong and the distance position R4 where the corner of the target vehicle 101 exists, using DBF processing, based on the power intensity and phase information at the frequency generated by the distance peak detecting units 31 to 3N (step S101). Here, in the case of the example shown in fig. 2, the angle +.r4=2°.

The azimuth detection unit 34 outputs information on the distance from the distance position R4 and the azimuth of the target vehicle 101 to the memory 4 and the corner detection unit 35, respectively. The memory 4 stores information of the distance and the azimuth at time t=t1 from the position R4 of the target vehicle 101 output from the azimuth detection unit 34.

The same signal processing is also performed for the next time t=t2, and information on the distance and the azimuth of the target vehicle 101 from the position R4 at the time t=t2 is output to the memory 4 and the corner detection unit 35. In the example shown in fig. 2, the information of the azimuth is the angle +.r4=2°.

The corner detection unit 35 compares the information of the distance and the azimuth of the distance position R4 at time t=t1 with the information of the distance and the azimuth of the distance position R4 at time t=t2, and determines whether or not the fluctuation amounts of the information reach a predetermined threshold.

The threshold value is input from an external source such as ECU (Electronic Control Unit), which is responsible for controlling the automatic driving in the vehicle 100. Alternatively, the threshold value stored in the memory 4 may be obtained.

When the fluctuation amount is smaller than the threshold value, the process returns to step S101 again (step S102). In the case of the example of fig. 2, since the fluctuation amount of the angle R4 is equal to or smaller than the threshold value, the process returns to the process of step S101 again. In addition, the time interval of time t=t1 and time t=t2 depends on the processing time for calculating the distance and the azimuth, which is in the order of about 10ms in the case of the millimeter wave radar.

The same signal processing is performed also at time t=tn, and the information of the distance and the azimuth of the distance position R4 of the target vehicle 101 at time t=tn is output to the memory 4 and the corner detection unit 35, respectively. In the case of the example of fig. 2, the angle r4=45°.

The corner detection unit 35 compares the information of the distance and the azimuth of the distance position R4 at times t=t1, t2=, … … tN-1 with the information of the distance and the azimuth of the distance position R4 at times t=tn, and determines whether or not the fluctuation amounts of both exceeds a set threshold value, and determines that a corner exists at the distance position if the fluctuation amount is greater than the threshold value (step S103). In the case of the example of fig. 2, the amount of change in angle R4 is 43 ° at time t=tn, exceeding the threshold value.

More precisely, the distance and orientation of the distance position R4 at time t=tn-1 represent the corner position of the target vehicle 101. In addition, since the object existing in the azimuth of 2 ° calculated as the azimuth of the distance position R4 at time t1< t < tN changes from the corner of the target vehicle 101 to the wall 105, the distance position R4 in the azimuth of 2 ° is converted into another distance position. In the case of fig. 2, at time t=tn, the distance position of the 2 ° azimuth changes from the distance position R4 to the distance position R14. Therefore, the threshold value of the fluctuation amount may be set to the fluctuation amount of the azimuth of a certain distance position of interest, the fluctuation amount of the distance in a certain azimuth of interest, or both.

By the above-described processing, in the detection device 1, the detection device can quickly detect the corner of the rear portion of the target vehicle 101 by determining based on the time variation amount of the distance position and the azimuth of the target vehicle 101.

In addition, the corner of the rear portion of the target vehicle 101 can be detected with high accuracy without using a transmission beam forming technique or the like, so that a low-cost detection device 1 can be provided.

< validity of detection device 1 >

Fig. 4 shows the results of experiments performed to confirm the validity of the detection device 1 of fig. 1.

At a time corresponding to time t=t2 shown on the left side of fig. 4, the azimuth of the distance R4 between the distance position R0 where the reflection intensity is strong and the distance position where the corner of the target vehicle 101 exists is calculated to be-15 °.

On the other hand, the distance to the corner of the target vehicle 101 shown on the right side of fig. 4 coincides with the distance position R4 for a time corresponding to time t=tn, and the azimuth of the distance position R4 is calculated to be +30°.

That is, it is confirmed that the azimuth from the position R4 is changed by 45 ° from the time t=t2 to the time t=tn, and it is confirmed that the corner of the rear portion of the target vehicle 101 can be detected by the detection device 1.

The reason why the azimuth of the distance position R4 at time t=tn is 30 ° is that the spectral leakage from the distance position R0 having strong reflection intensity affects the distance position R4, and the azimuth of the distance position R0 is calculated.

In addition, as a more preferable embodiment, the corner detection unit 35 detects the corner of the target vehicle 101 when it is determined that the threshold value is exceeded 2 times or more, whereby the corner of the target vehicle 101 can be accurately detected even when there is an influence of noise such as external interference.

< other configuration example and operation example of detection device >)

Fig. 5 is an explanatory view showing another example of the detection device 1 of fig. 1. Fig. 6 is a flowchart showing an example of the detection process performed by the detection device of fig. 5.

The detecting device 1 shown in fig. 5 is different from the detecting device 1 of fig. 1 in that switches SW1, SW2 and a transmitting antenna TXANT2 are newly provided in a transmitting-receiving antenna/analog section 2.

The switch SW1 switches the connection of the frequency generator VCO with the transmitting antenna TXANT 1. The switch SW2 switches the connection of the frequency generator VCO with the transmitting antenna TXANT2. The switches SW1 and SW2 are switching units.

The switches SW1 and SW2 switch the connection targets based on the corner detection signal output from the corner detection unit 35. The 2 nd transmitting antenna, i.e., the transmitting antenna TXANT2, is an antenna having a tilt characteristic of a downward depression angle, for example, and is an antenna dedicated to detecting the curb 106 shown in fig. 7.

Next, an operation of the detection device 1 of fig. 5 will be described.

Fig. 6 is a flowchart showing an example of the detection process performed by the detection device of fig. 5. Here, the processing of steps S201 to S203 in the flowchart of fig. 6 is the same processing as steps S101 to S103 in the flowchart of fig. 3.

In the detection device 1 shown in fig. 5, the transmitting antenna TXANT1 is connected to the frequency generator VCO by the switch SW1 until the corner of the target vehicle 101 is detected (steps S201 to S203), that is, until time t < tN.

Then, when the corner detection signal is output from the corner detection unit 35 at the time of detecting the corner of the target vehicle 101 at time t=tn, the switch SW1 is turned OFF and the switch SW2 is turned ON. As a result, the transmitting antenna TXANT2 is connected to the frequency generator VCO.

As described above, the transmitting antenna TXANT2 has, for example, a downward, i.e., depression angle, inclination characteristic, and is an antenna dedicated to detecting the curb 106. At time t=tn+1, the distance after the fluctuation in the azimuth of interest, for example, the curb 106 disposed at the distance position R14 of fig. 2 is detected using the transmitting antenna TXANT2 (step S204). In the process of step S204, if the curb 106 is not detected, the process of step S201 may be returned.

In this way, after the corner of the target vehicle 101 is detected, the curb 106 is detected, whereby the corner position of the target vehicle 101 can be determined with higher accuracy.

(embodiment 2)

Structural example of detection device 1

Fig. 11 is an explanatory diagram showing an example of the structure of the detection device 1 according to embodiment 2.

The detecting device 1 shown in fig. 11 is different from the detecting device 1 shown in fig. 1 of the above-described embodiment 1 in the configuration of the digital signal processing section 3. The other structures are the same as those in fig. 1, and therefore, the description thereof is omitted.

The digital signal processing unit 3 includes distance peak detection units 31 to 3N, an azimuth detection unit 34, a corner detection unit 35, and a newly provided surface detection unit 36. The distance peak detection units 31 to 3N convert signals converted into digital signals by the analog/digital converters ADC1 to ADCN of the transmitting/receiving antenna/analog unit 2 from time domain signals to frequency domain signals by FFT processing, for example.

Then, frequency proportional to the distance from the object to the detection device 1 and power intensity and phase information at the frequency are extracted from the frequency domain signal, and the power intensity and phase information at the frequency are output to the azimuth detection unit 34.

The azimuth detecting unit 34 detects the azimuth in which the object exists, for example, by using the signal processing of DBF, based on the power intensity and phase information at the frequency generated by the distance peak detecting units 31 to 3N, and outputs the information of the distance and azimuth of the object to the memory 4 and the face detecting unit 36.

The memory 4 stores information of the distance and the orientation of the object output from the orientation detection unit 34 for each time period t=t1 to t=tn, and outputs the information of the distance and the orientation of the object for each time period to the corner detection unit 35 and the face detection unit 36. Here, N of time t=tn is different from the number N of the above-described reception channels.

The surface detecting unit 36 determines whether or not the objects constitute the surface of the same object based on the information of the distance and the direction of the objects output from the direction detecting unit 34 and the information of the distance and the direction of the objects stored in the memory 4 for each time, and outputs a determination result signal to the corner detecting unit 35 when it is determined that the objects constitute the surface of the same object.

When receiving the determination result signal from the surface detecting unit 36, the corner detecting unit 35 determines whether or not there is a corner of the object based on the information on the distance and the azimuth of the object output from the azimuth detecting unit 34 and the information on the distance/azimuth of the object at each time stored in the memory 4, and outputs a corner detection signal when a corner is detected.

Operation example of detection device 1

Fig. 12 is an explanatory diagram of the operation performed by the detection device 1 of fig. 11. Fig. 13 is a flowchart showing an example of the detection process performed by the detection device 1 of fig. 11. The main body of the processing in the flowchart of fig. 13 is mainly based on the operation of the digital signal processing unit 3.

First, automatic parking is started at time t=t1 of fig. 12. At time t=t1, the detection device 1 emits electromagnetic waves to the target vehicle 101, and the reflected waves from the target vehicle 101 are received by the receiving antennas RXANT1 to RXANTN of the detection device 1.

The reception signals received by the reception antennas RXANT1 to N are frequency-converted and converted into digital signals by the transmitting/receiving antenna/analog unit 2 constituting the detection device 1, and are output to the digital signal processing unit 3.

After the digital signal is subjected to FFT processing by the distance peak detection units 31 to 3N included in the digital signal processing unit 3, a frequency proportional to the distance from the object to the detection device 1 and power intensity and phase information at the frequency are extracted. The power intensity and phase information at the extracted frequency is output to the azimuth detection unit 34.

The azimuth detection unit 34 obtains information on the distance and azimuth of the distance position R0 having strong reflection intensity, and information on the distance position R4 and azimuth, which are distances between the distance position R0 having strong reflection intensity and the distance position where the corner of the target vehicle 101 is present, using DBF processing based on the power intensity and phase information at the frequencies generated by the distance peak detection units 31 to 3N (step S301). In the example of fig. 12, angle +.r0=45°, angle +.r4=2°.

Here, if there is no difference between the azimuth of the distance position R0 and the azimuth of the distance position R4, which are strong in reflection intensity (step S302), it is considered that 2 or more reflection points cannot be detected from the target vehicle 101, which is the object, and the process returns to step S301. Alternatively, the flow of automatic parking may be stopped or restarted.

If there is a certain difference between the azimuth of the distance position R0 having strong reflection intensity and the azimuth of the distance position R4 (step S302), it is considered that 2 or more reflection points are successfully detected from the target vehicle 101, and the information on the distance and azimuth of the distance positions R0 and R4 is output to the memory 4 and the corner detection unit 35.

The memory 4 stores information of the distance and the azimuth at time t=t1 from the position R0 of the target vehicle 101 and information of the distance and the azimuth at time t=t1 from the position R4, which are input from the azimuth detecting unit 34.

The same signal processing is also performed for the next time t=t2, and information on the distance and the azimuth of the distance positions R0 and R4 of the target vehicle 101 at the time t=t2 is output to the memory 4 and the surface detection unit 36 (step S303). In the example of fig. 12, angle +.r0=45°, angle +.r4=2°.

The surface detection unit 36 determines whether or not the distance position R0 and the distance position R4 constitute an element of the surface of the same object based on the distance and orientation information of the distance positions R0 and R4 at time t=t1 and the distance and orientation information of the distance positions R0 and R4 at time t=t2 (step S304).

If the distance position R0 and the distance position R4 are elements constituting the surface of the same object, the trajectories of the distance position R0 and the distance position R4 at the respective times are aligned on a certain straight line as shown in fig. 12.

The corner detection unit 35 compares the information of the distance and the azimuth of the distance positions R0 and R4 at time t=tn (step S305) with the information of the distance and the azimuth of the distance position R4 at time t=t1, t2, … … tN-1, and determines whether or not the fluctuation amounts of the two exceeds a certain threshold value (step S306).

Then, when the fluctuation amount is smaller than the threshold value, the process returns to step S305. In the example of fig. 12, since the fluctuation amount of the angle R4 is equal to or smaller than the threshold value, the process returns to step S305 again.

Here, the threshold value is also input from an external portion such as an ECU that is responsible for controlling the automatic driving in the vehicle 100. Alternatively, the threshold value stored in the memory 4 may be obtained.

When the fluctuation amount exceeds the threshold value, it is determined that there is a corner at the distance position, that is, the distance position R4 in fig. 12 (step S307). In the example of fig. 12, when time t=tn, the variation amount of angle R4 is 43 °, and exceeds the threshold value. More precisely, the distance and orientation of the distance position R4 at time t=tn-1 represent the corner position of the target vehicle 101.

Further, since the object existing in the azimuth of 2 ° calculated as the azimuth of the distance position R4 at the time t1< t < tN changes from the corner of the target vehicle 101 to the wall 105 or the curb, the distance position R4 in the azimuth of 2 ° changes to another distance position.

In the case of fig. 12, the distance position of the 2 ° azimuth changes from the distance position R4 to the distance position R14 at time t=tn. Therefore, the threshold value of the fluctuation amount may be set to the fluctuation amount of the azimuth of a certain distance position of interest, or may be set to the fluctuation amount of the distance in a certain azimuth of interest. Or both may be provided.

The detection device 1 is provided with the surface detection unit 36 that determines whether or not the surface of the same object is formed by the time trace of the distance positions R0 and R4 at time t=t2 by the above operation, whereby the corner portion of the rear portion of the target vehicle 101 can be detected more accurately.

Thus, the accuracy of automatic parking can be improved.

Further, as a more preferable example, the corner of the vehicle 101 is determined to be the corner of the target vehicle 101 in the case where the threshold value is continuously exceeded 2 times or more in the threshold value determination by the corner detection unit 35, which is a plurality of times in the processing of step S306 by the above-described corner detection unit 35, whereby the corner of the vehicle 101 can be detected more accurately even in the case where there is an influence of noise such as external interference.

< other configuration example and operation example of the detection apparatus 1 >

In addition, the detection device 1 may be configured such that the switches SW1 and SW2 and the transmitting antenna TXANT2 shown in fig. 5 of the above-described embodiment 1 are newly provided in the configuration of the detection device 1 of fig. 11.

In this case, the connection structure of the newly provided switches SW1 and SW2 and the transmitting antenna TXANT2 is the same as fig. 5, and therefore, the description thereof is omitted. The transmitting antenna TXANT2 is also an antenna having a tilt characteristic of a downward depression angle, and is an antenna dedicated to detecting the curb 106 and the like of fig. 7.

Fig. 14 is a flowchart showing an example of detection processing in the detection device 1 of fig. 11 in which new switches SW1 and SW2 and a transmission antenna TXANT2 are provided.

Here, the processing of steps S401 to S407 in the flowchart of fig. 14 is the same as the processing of steps S301 to S307 in the flowchart of fig. 13.

In the detection device 1, the transmission antenna TXANT1 is connected to the frequency generator VCO by the switch SW1 until the corner of the target vehicle 101 is detected (steps S401 to S407), that is, until the time t < tN.

Then, when the corner detection signal is output at the time t=tn and the corner of the target vehicle 101 is detected, the switch SW1 is turned OFF and the switch SW2 is turned ON (step S408). As a result, the transmitting antenna TXANT2 is connected to the frequency generator VCO.

As described above, the transmitting antenna TXANT2, for example, having a downward depression angle characteristic, is an antenna dedicated to detecting the curb 106. At time t=tn+1, the distance after the fluctuation in the azimuth of interest, for example, the wall 105 disposed at the distance position R14 of fig. 2 is detected using the transmitting antenna TXANT2 (step S409).

In this way, the edge of the target vehicle 101 is also detected, and then the edge of the target vehicle 101 is detected, whereby the edge position of the target vehicle 101 can be determined with higher accuracy.

Embodiment 3

In embodiment 3, an example will be described in which the host vehicle and the target vehicle 101 are not horizontally aligned, but, for example, when the target vehicle 101 has a certain inclination angle, it is appropriate to detect the corner of the vehicle 101.

Structural example of detection device 1

Fig. 15 is an explanatory diagram showing an example of the structure of the detection device 1 according to embodiment 3.

The detecting device 1 shown in fig. 15 is different from the detecting device 1 of fig. 11 of the above-described embodiment 2 in that a threshold value adjusting section 37 is newly provided in the digital signal processing section 3.

The surface detecting unit 36 determines whether or not the objects constitute the surface of the same object, calculates the inclination angle of the surface, and outputs the calculation result to the threshold value adjusting unit 37 as inclination angle information. The inclination information is correction information.

A preset threshold value is input to the surface detection unit 36. The threshold value is obtained by an external input from an ECU or the like that is responsible for controlling the automatic driving in the vehicle 100. Alternatively, the threshold value stored in the memory 4 may be obtained. The other structures are the same as those in fig. 4, and therefore, the description thereof is omitted.

The threshold value adjusting unit 37 calculates a correction threshold value corrected in accordance with the inclination angle information outputted from the face detecting unit 36, and outputs the correction threshold value to the corner detecting unit 35.

Operation example of detection device 1

Fig. 16 is an explanatory diagram of the operation of the detection device 1 of fig. 15. Fig. 18 is a flowchart showing an example of the detection process performed by the detection device 1 shown in fig. 15. In the flowchart shown in fig. 18, the digital signal processing unit 3 mainly performs processing.

First, at time t=t1 in fig. 16, the process of automatic parking is started. At time t=t1, the detection device 1 emits electromagnetic waves to the target vehicle 101, and the reflected waves from the target vehicle 101 are received by the receiving antennas RXANT1 to RXANTN of the detection device 1. In the example of fig. 16, it is assumed that the target vehicle 101 is parked at an inclination angle of, for example, 5 °, and the vehicle speed of the host vehicle is moved at 10km per hour.

The reception signals received by the reception antennas RXANT1 to RXANT are frequency-converted and converted into digital signals by the transmitting/receiving antenna/analog section 2 provided in the detection device 1, and are output to the digital signal processing section 3.

The digital signal is subjected to FFT processing by the distance peak detection units 31 to 3N included in the digital signal processing unit 3, frequency proportional to the distance from the object to the detection device 1 and power intensity and phase information at the frequency are extracted, and the extracted power intensity and phase information at the frequency are output to the azimuth detection unit 34.

The azimuth detection unit 34 obtains information on the distance and azimuth of the distance position R0 having strong reflection intensity and information on the distance and azimuth of the distance position R4 between the distance position R0 having strong reflection intensity and the distance position where the corner of the target vehicle 101 is present, using DBF processing, based on the power intensity and phase information at the frequency generated by the distance peak detection units 31 to 3N (step S501). In the example of fig. 16, angle +.r0=50°, angle +.r4=6.5°.

Here, if there is no difference between the azimuth of the distance position R0 and the azimuth of the distance position R4, which are strong in reflection intensity (step S502), it is considered that 2 or more reflection points cannot be detected from the target vehicle 101, which is the object, and the process returns to step S501. Alternatively, the automatic parking process may be stopped or the detection device 1 may be restarted.

If there is a difference between the azimuth of the distance position R0 and the azimuth of the distance position R4, which is strong in reflection intensity (step S502), it is considered that 2 or more reflection points are successfully detected from the target vehicle 101, and information on the distance and the azimuth of the distance positions R0 and R4 is output to the memory 4 and the corner detection unit 35.

The same signal processing is also performed for the next time t=t2, and information on the distance and the azimuth of the distance positions R0 and R4 of the target vehicle 101 at the time t=t2 is output to the memory 4 and the surface detection unit 36. Here, in the example of fig. 16, the angle +.r0=50°, and the angle +.r4=6.7°.

The surface detection unit 36 determines whether or not the distance position R0 and the distance position R4 constitute an element of the surface of the same object based on the acquired threshold value, with respect to the distance and orientation information of the distance positions R0 and R4 at time t=t1 and the distance and orientation information of the distance positions R0 and R4 at time t=t2 (step S504).

If the distance position R0 and the distance position R4 are elements constituting the surface of the same object, the trajectories of the distance position R0 and the distance position R4 at the respective times are aligned on a certain straight line as shown in fig. 16.

Fig. 17 is an explanatory diagram showing a relationship between the distance and the azimuth angle at each time of the distance positions R0 and R4 between the host vehicle 100 and the target vehicle 101.

Fig. 17 (a) is a graph showing distances between the respective times of the distance positions R0 and R4 in a state where the host vehicle 100 and the target vehicle 101 are juxtaposed with each other at an inclination of about 5 °.

Fig. 17 (b) is a graph similarly showing the orientations of the own vehicle 100 and the target vehicle 101 at respective times of distance positions R0 and R4 in a state of being juxtaposed with each other with an inclination of about 5 °.

As shown in fig. 17, when the host vehicle 100 and the target vehicle 101 are not horizontally juxtaposed, it is confirmed that the distance and the azimuth of the distance positions R0 and R4 gradually change with the passage of time.

That is, the surface detecting unit 36 and the corner detecting unit 35 need to take into consideration the amount of fluctuation in the distance and the azimuth of the target vehicle 101, which is the object caused by the inclination angle, and thus the threshold value corresponding to the inclination angle is input to the surface detecting unit 36.

For example, if an inclination angle of 5 ° or less is to be handled, the threshold value of the azimuth fluctuation is a value obtained by adding a fluctuation margin due to noise to 0.2 °. The information of the inclination angle of the host vehicle 100 and the target vehicle 101 detected by the surface detection unit 36 is output to the threshold adjustment unit 37. The threshold value adjusting unit 37 calculates a correction threshold value, which is a threshold value corrected in accordance with the inclination angle information, and outputs the correction threshold value to the corner detecting unit 35.

The corner detection unit 35 compares the information of the distance and the direction of the distance positions R0 and R4 at time t=tn with the information of the distance and the direction of the distance position R4 at time t=t1, t2, … … tN-1, and determines whether or not the fluctuation amounts of the two exceeds the correction threshold (step S506).

When the fluctuation amount is smaller than the correction threshold value, the process returns to step S505 again. In the example of fig. 16, since the fluctuation amount of the angle R4 is equal to or smaller than the correction threshold value, the process returns to step S505.

When the fluctuation amount exceeds the correction threshold value, it is determined that there is a corner at the distance position, that is, the distance position R4 in fig. 16 (step S507). More precisely, the distance and orientation of the distance position R4 at time t=tn-1 represent the corner position of the target vehicle 101.

Further, since the object existing in the azimuth of 10.7 ° calculated as the azimuth of the distance position R4 in the time t1< t < tN changes from the corner of the target vehicle 101 to the wall 105 or the curb, the distance position R4 in the azimuth of 2 ° changes to another distance position.

In the case of fig. 16, the distance position of the 2 ° azimuth changes from the distance position R4 to the distance position R14 at time t=tn. Therefore, the threshold value of the fluctuation amount may be set to the fluctuation amount of the azimuth of a certain distance position of interest, the fluctuation amount of the distance in a certain azimuth of interest, or both.

By the above-described operation, even when the host vehicle 100 and the target vehicle 101 are juxtaposed not horizontally but at a certain inclination, the corner of the rear portion of the target vehicle 101 can be detected promptly.

Thus, even if the target vehicle 101 or the like is parked obliquely, the automatic parking process can be performed with high accuracy.

In this case, the corner of the target vehicle 101 is also determined as being a corner of the vehicle 101 in the process of step S506 performed by the corner detection unit 35, that is, in the case where the correction threshold value is exceeded 2 times or more in the correction threshold value determination performed by the corner detection unit 35, whereby the corner of the vehicle 101 can be detected more accurately even in the case where there is an influence of noise such as external interference.

As described with reference to fig. 14 of embodiment 2, the detection device 1 of fig. 15 may be configured to newly include the switches SW1 and SW2 and the transmitting antenna TXANT2 shown in fig. 5 of embodiment 1 of the present invention.

Here, the newly provided transmitting antenna TXANT2 is also an antenna having a downward dip characteristic, and is an antenna dedicated to detecting the curb 106 or the like of fig. 7.

Fig. 19 is a flowchart showing an example of detection processing in the detection device provided with the new switches SW1 and SW2 and the transmission antenna TXANT 2.

Here, the processing of steps S601 to S607 in the flowchart of fig. 19 is the same as the processing of steps S501 to S507 in the flowchart of fig. 18.

In the detection device 1, the transmission antenna TXANT1 is connected to the frequency generator VCO by the switch SW1 until the corner of the target vehicle 101 is detected (steps S601 to S607), that is, until the time t < tN.

Then, when the corner detection signal is output at the time t=tn and the corner of the target vehicle 101 is detected, the switch SW1 is turned OFF and the switch SW2 is turned ON (step S608). As a result, the transmitting antenna TXANT2 is connected to the frequency generator VCO.

As described above, the transmitting antenna TXANT2, for example, having a downward depression angle characteristic, is an antenna dedicated to detecting the curb 106. At time t=tn+1, the distance after the fluctuation in the azimuth of interest, for example, the curb 106 shown in fig. 7 is detected using the transmitting antenna TXANT2 (step S609).

Embodiment 4

In embodiment 4, a technique of performing automatic parking processing using information of the free parking space 160 detected before entering the automatic parking processing on the premise that a rear corner of the target vehicle 101 is recognized will be described. The free space 160 is information of an area where the vehicle 100 can park, and is, for example, a parking space between the vehicle 101 and the vehicle 102 as shown by a broken line box in the example of fig. 7.

If the rear corner of the target vehicle 101 is detected and identified by the empty space detection before the automatic parking process is entered, there is a possibility that the target vehicle 101 moves back and forth at the time when the own vehicle 100 enters the automatic parking process. Therefore, it is necessary to identify the corners of the target vehicle 101 from the side.

Details of this technique are described below.

Structural example of detection device 1

Fig. 20 is an explanatory diagram showing an example of the structure of the detection device 1 according to embodiment 4.

In the detection device 1 shown in fig. 20, a memory 4a is newly provided in the detection device 1 shown in fig. 11 according to embodiment 2. The memory 4a stores the distance and the azimuth of the corner portion of the target vehicle 101 detected by the empty space detection.

The information of the distance and the azimuth of the corner portion of the target vehicle 101 detected by the free space is, for example, information obtained from a sensor connected to the outside. Alternatively, the information detected by the detection device 1 may be used.

The corner detection unit 35 determines whether or not a corner of the object is present based on the information on the distance and the orientation of the object output from the orientation detection unit 34, the information on the distance and the orientation of the object at each time stored in the memory 4, and the information on the distance and the orientation of the object detected by the free space stored in the memory 4a, and outputs a corner detection signal when the corner of the object is detected.

Operation example of detection device 1

The detection processing performed by the detection device 1 will be described below.

Fig. 21 is a flowchart showing an example of the detection process performed by the detection device 1 of fig. 20.

In the automatic parking performed by the detection device 1 of fig. 20, the process of detecting the free space is performed before the process of entering the automatic parking, as described above, on the premise that the initial position of the target vehicle 101 is known.

In fig. 21, the operation for time t0< t < tN-1 is the same as the processing in steps S301 to 306 in fig. 13 in embodiment 2, and therefore, the description thereof is omitted.

At time t=tn, the distance and the azimuth of the distance position R4 of the target vehicle 101 are detected, and whether the target vehicle 101 moves back and forth after the idle parking space detection is confirmed against the corner position information of the target vehicle 101 stored in the memory 4a (step S707).

If the corner detection of the target vehicle 101 by the empty space detection of the above sensor matches the result of the corner detection by the corner detection unit 35, it is determined that the target vehicle 101 has not moved after the empty space detection (step S708), and the automatic parking process is performed.

If the corner detection of the target vehicle 101 by the empty space detection does not coincide with the result of the corner detection by the corner detection section 35, the process of automatic parking is suspended. Alternatively, if the safety can be confirmed based on the positional relationship between the target vehicle 101 and the vehicle 102 located behind the vehicle 101 shown in fig. 7, the process of automatically parking may be maintained.

In addition, when the automatic parking process is performed, the detection device 1 again confirms the position of the corner of the target vehicle 101, and thus the correction process of automatic parking can be performed.

By the above, even if the target vehicle 101 moves forward or backward after the idle parking space is detected, the process of automatic parking or the stopping thereof can be safely performed.

This can improve the safety during automatic parking.

The invention obtained by the present inventors has been specifically described above based on the embodiments, but the invention is not limited to the above embodiments, and various modifications can be made without departing from the gist thereof.

Description of the reference numerals

1. Detection device

2. Transmitting/receiving antenna/analog part

3. Digital signal processing unit

4. Memory device

4a memory

31. Distance peak value detection unit

34. Azimuth detecting unit

35. Corner detection part

36. Surface detection unit

37. Threshold value adjusting unit

100. Vehicle with a vehicle body having a vehicle body support

101. Vehicle with a vehicle body having a vehicle body support

105. Wall with a wall body

106. Curb stone

VCO frequency generator

TXANT transmitting antenna

RXANT receiving antenna

MIX mixer

ADC analog-to-digital converter

SW1 switch

SW2 switch.

Claims

1. A detection apparatus, characterized by comprising:

a 1 st transmitting antenna for transmitting a modulated signal to a space;

A plurality of receiving antennas for receiving reflected waves of the modulated signal transmitted from the 1 st transmitting antenna;

a calculation unit that obtains a distance and an azimuth of an object from received signals of the reflected waves received by a plurality of the receiving antennas at regular intervals, and calculates a time-varying amount of the distance from the obtained distance and azimuth of the object; and

a corner detection unit that detects a corner of the object based on the time variation calculated by the calculation unit,

the corner detection unit compares the time variation calculated by the calculation unit with a predetermined threshold value, and outputs a corner detection signal indicating that the corner of the object is detected when the time variation exceeds the threshold value.

2. The detection apparatus according to claim 1, wherein:

the corner detection unit detects, as a corner of the object, a point of the object corresponding to the distance and the azimuth calculated by the calculation unit before the time when the time variation exceeds the threshold.

3. The detection apparatus according to claim 1, wherein:

the corner detection unit outputs the corner detection signal when the time variation calculated by the calculation unit exceeds the threshold value at least 2 times in succession.

4. The detection apparatus according to claim 1, wherein:

a memory for storing the distance and direction of the object calculated by the calculating unit,

the corner detection unit reads the distance and the azimuth of the object from the memory, and calculates the time variation of the distance.

5. The detection apparatus according to claim 1, characterized by comprising:

a 2 nd transmitting antenna having a dip characteristic of a depression angle, spatially transmitting the modulated signal; and

a switch section that switches a connection target of the 1 st transmitting antenna and the 2 nd transmitting antenna based on the corner detection signal,

the switch section switches so that the 1 st transmitting antenna is connected to a frequency generator that generates the modulation signal before the corner detection signal is output from the corner detection section, and so that the 2 nd transmitting antenna is connected to the frequency generator when the corner detection signal is output from the corner detection section.

6. The detection apparatus according to claim 1, wherein:

the corner detection unit compares a distance and an orientation of a corner of the object, which are input from the outside in advance, with the distance and the orientation of the corner detected by the detection unit, determines that the object is not moving when the distance and the orientation match, and detects the corner of the object based on the time variation calculated by the calculation unit.

7. A detection apparatus, characterized by comprising:

a 1 st transmitting antenna for transmitting a modulated signal to a space;

a calculation unit that obtains a distance and an azimuth of an object at regular intervals from received signals of the reflected waves received by the plurality of receiving antennas, and calculates a time-varying amount of the distance from the obtained distance and azimuth of the object;

a corner detection unit that detects a corner of the object based on the time variation calculated by the calculation unit; and

a plane detection unit that determines whether or not the objects constitute a plane of the same object based on the time variation of the distance calculated by the calculation unit, and outputs a determination result signal to the corner detection unit when it is determined that the objects constitute the same plane,

the corner detection unit compares the time variation calculated by the calculation unit with a predetermined threshold value when the determination result signal is received, detects a corner of the object when the time variation exceeds the threshold value, and outputs a corner detection signal indicating that the corner of the object is detected.

8. The detection apparatus according to claim 7, wherein:

the surface detection unit judges the surface of the object based on the distance and the direction of the object obtained by the calculation unit at regular intervals in a dot-like manner,

9. The detection apparatus according to claim 8, wherein:

10. The detection apparatus according to claim 9, wherein:

11. A detection apparatus, characterized by comprising:

a 1 st transmitting antenna for transmitting a modulated signal to a space;

a surface detection unit that determines whether or not an object forms a surface of the same object based on the time variation of the distance calculated by the calculation unit, and outputs a determination result signal to the corner detection unit when it is determined that the object forms the same surface;

an adjustment unit for generating correction information in accordance with the inclination information; and

the surface detecting unit detects an amount of inclination of the object based on the time-varying amount of the distance calculated by the calculating unit, outputs the detected amount of inclination as the correction information,

the corner detection unit corrects a preset threshold value based on the correction information, compares the corrected threshold value with the time variation calculated by the calculation unit when the determination result signal is received, detects a corner of the object when the time variation exceeds the corrected threshold value, and outputs a corner detection signal indicating that the corner of the object is detected.

12. The detection apparatus according to claim 11, wherein:

13. The detection apparatus according to claim 12, wherein:

14. The detection apparatus according to claim 11, wherein: