JP6157565B2 - Object detection device - Google Patents

Description

  The present invention relates to an object detection device that is mounted on a vehicle and detects peripheral objects.

  As a method for calculating a predicted relative position of a conventional object detection device, for example, there is a technique disclosed in Patent Document 1. In this conventional object detection apparatus, the predicted relative position of the target object is calculated using the vehicle speed and the yaw rate.

JP2011-192226A (pages 5-6, FIG. 1)

  The conventional object detection device is based on the assumption that the host vehicle is traveling at an equal speed or turning at an equal angular speed. If the host vehicle accelerates or decelerates or the turning angular speed changes, the predicted relative position is determined. There was a problem that the accuracy of.

  The present invention has been made to solve the above-described problems. Even when the host vehicle performs acceleration / deceleration or when the turning angular velocity changes, the predicted relative position and predicted relative position of the target object can be accurately obtained. An object of the present invention is to obtain an object detection device that calculates speed.

In the object detecting apparatus according to the invention is mounted on a vehicle, the relative distance of the target object by transmitting and receiving signals, the azimuth and the relative speed to a object detection device for periodically detecting, as the movement change amount of the vehicle A movement change amount acquisition unit for acquiring acceleration and turning angular velocity , a calculation unit for calculating the relative distance, azimuth angle and relative speed of the target object based on a signal reflected from the target object, and the target object calculated by the calculation unit distance relative, track storage unit for storing a track including the azimuth and the relative velocity and the turning angular velocity, the movement change amount with based on the relative distance, azimuth and the relative velocity and the turning angular velocity at the previous stored track in the track storage unit using the obtained translational changes by the acquisition unit, the relative distance of the track, the prediction unit, this Starring the calculating section that predicts azimuth and the relative velocity Relative distance of the target object, the azimuth and the relative speed, relative distance predicted by the prediction unit, based on the azimuth and the relative speed, there is a correlation between this calculated target object and the previous track If there is a correlation in the correlation unit that determines whether or not, and the determination by this correlation unit, the wake is updated with the relative distance, azimuth angle and relative speed and turning angular velocity of the target object calculated this time, When there is no correlation, as a new wake, it includes a wake update unit that stores the relative distance, azimuth and relative speed of the target object calculated this time and the turning angular velocity in the wake storage unit , the movement change amount acquisition unit, The turning angular acceleration of the vehicle is calculated using the turning angular velocity stored in the wake, and the prediction unit uses the turning angular acceleration of the vehicle to predict the azimuth .

According to the present invention, there is provided an object detection device that is mounted on a vehicle and periodically detects a relative distance, an azimuth angle, and a relative speed of a target object by transmitting and receiving signals , and the acceleration and turning as the movement change amount of the vehicle. Based on the signal reflected from the target object, the movement change amount acquisition unit for acquiring the angular velocity , the calculation unit for calculating the relative distance, the azimuth and the relative speed of the target object, the relative distance of the target object calculated by the calculation unit , track storage unit for storing a track including the azimuth and the relative velocity and the turning angular velocity acquired in this track storage unit relative distance in the previous stored track, by the movement change amount acquiring unit together based on azimuth and the relative velocity and the turning angular velocity using a mobile variation which is a relative distance between the track prediction unit for predicting the azimuth and the relative velocity, this calculated target object relative the calculating section Determines away, and azimuth and the relative speed, relative distance predicted by the prediction unit, based on the azimuth and the relative speed, whether there is a correlation between this calculated target object and the previous track If there is a correlation in the correlation unit and the determination by this correlation unit, the wake is updated with the relative distance, azimuth angle and relative speed and turning angular velocity of the target object calculated this time. The wake update unit stores the relative distance, azimuth angle and relative speed , and the turn angular velocity of the target object calculated this time in the wake storage unit as a new wake , and the movement change amount acquisition unit stores the turn stored in the wake. The angular velocity is used to calculate the turning angular acceleration of the vehicle, and the prediction unit uses the turning angular acceleration of the vehicle to predict the azimuth, so even when the vehicle performs acceleration / deceleration or when the turning angular velocity changes ,accuracy It is possible to calculate the predicted relative position and velocity of the Ku target object.

It is a block diagram which shows the object detection apparatus by Embodiment 1 and Embodiment 2 of this invention. It is a figure which shows the relative position and relative velocity relationship between the object detection apparatus by Embodiment 1 and Embodiment 2 of this invention, and a target object.

Embodiment 1 FIG.
1 is a block diagram showing an object detection apparatus according to Embodiment 1 of the present invention.
In FIG. 1, an object detection apparatus according to Embodiment 1 is mounted on a host vehicle and periodically detects a relative position and a relative speed of a target object by transmitting and receiving radio waves, and is configured as follows. Yes.
The radio wave transmission / reception unit 1 transmits radio waves and receives radio waves reflected by the target object. The relative position speed calculation unit 2 (calculation unit) calculates a relative position and a relative speed of the target object with respect to the host vehicle based on the received radio wave, and inputs the calculated relative position and relative speed to the correlation unit 3.
The wake storage unit 4 stores wake information including the relative distance Rt to the target object 11 at the previous time, the relative speed Vt, and the azimuth angle θt.

Based on the output from the acceleration sensor 6 that detects the acceleration of the host vehicle and the yaw rate sensor 7 that detects the turning angular velocity of the host vehicle and the track information of the target object stored in the track storage unit 4, the prediction unit 5 The predicted relative distance, predicted relative speed, and predicted azimuth angle are calculated and input to the correlation unit 3.
The correlator 3 includes information on the target object observed this time calculated by the relative position speed calculator 2 and predicted information on the target object predicted by the prediction unit 5 from the track stored in the track storage unit 4. Determine if there is a correlation between them.
If there is a correlation between the target object observed this time and the track used for prediction based on the determination result of the correlation unit 3, the wake update unit 8 calculates the relative position of the target object calculated this time and The wake used for prediction is updated based on the relative speed, and if there is no correlation, the relative position and relative speed of the target object calculated this time are stored in the wake storage section 4 as a new wake.
Note that the movement change amount acquisition unit having the acceleration sensor 6 and the yaw rate sensor 7 acquires acceleration from the acceleration sensor 6 as the movement change amount, and outputs the yaw rate sensor 7 as described later in the second embodiment. The turning angular acceleration is calculated from a certain turning angular velocity.

FIG. 2 is a diagram showing the relative position and relative velocity relationship between the object detection apparatus and the target object according to the first embodiment of the present invention.
FIG. 2 shows the relative position and relative velocity relationship between the object detection device 10 and the target object 11, and the state of the acceleration A and the turning angular velocity ω of the object detection device 10 mounted on the host vehicle. The target object 11 is traveling at a relative speed V with respect to the object detection apparatus 10 at a relative distance R in the direction of the azimuth angle θ. In FIG. 2, the subscripts of each symbol are omitted.

Next, the operation will be described.
The radio wave transmission / reception unit 1 transmits a radio wave subjected to frequency modulation in which the frequency rises and falls in a triangular wave shape with the passage of time, as in the widely known FMCW (Frequency Modulation Continuous Wave) radar. The transmitted radio wave is reflected by the target object and received again by the radio wave transmission / reception unit 1.
In the radio wave transmission / reception unit 1, the reception antenna ANTa and the reception antenna ANTb are arranged apart from each other by a distance d, and are received by each reception antenna and mixed with the transmitted radio wave, thereby receiving the reception signal a and reception Signals b are respectively generated and input to the relative position speed calculation unit 2.

In the relative position speed calculation unit 2, FFT (Fast Fourier Transform) is performed for the frequency increase period and the frequency decrease period of the transmitted radio wave of each of the reception signal a and the reception signal b, and the respective peak frequency and phase φa and φb are extracted.
Here, the peak frequency and phase in the frequency increase period of the received signal a are fau and φau, the peak frequency and phase in the frequency decrease period of the received signal a are fad and φad, and the peak frequency and phase in the frequency increase period of the received signal b are The peak frequency and phase in the frequency falling period of fbu, φbu, and received signal b are defined as fbd and φbd, respectively.
Further, it is assumed that the relative distance R from the target object 11 to the object detection apparatus 10 of the first embodiment is sufficiently larger than the distance d between the reception antenna ANTa and the reception antenna ANTb, and fau = fbu = fu, fad = Fbd = fd. Further, φau = −φad = φa and φbu = −φbd = φb are defined.
From the above, the relative distance Ro, the relative velocity Vo, and the azimuth angle θo to the target object are easily derived from the distance measurement principle of the FMCW radar and the principle of phase difference detection, by calculating the equation (1). The

  In equation (1), c is the speed of light, T is the modulation period, F is the modulation width, and fc is the modulation center frequency. The relative distance Ro, the relative speed Vo, and the azimuth angle θo calculated as described above are input to the correlation unit 3 as the observed relative distance, the observed relative speed, and the observed azimuth angle to the target object observed this time. Is done.

On the other hand, the process with respect to the wake produced | generated based on the information of the target object 11 observed until the last time is demonstrated.
The information of the track of the target object 11 stored in the track storage unit 4 includes the relative distance Rt, the relative speed Vt, and the azimuth angle θt to the target object 11 at the previous time point. 5 is input.

FIG. 2 shows the relative position and relative velocity relationship between the object detection device 10 and the target object 11 according to the first embodiment, and the state of acceleration A and turning angular velocity ω of the object detection device 10 mounted on the host vehicle. The acceleration A of the host vehicle is detected by the acceleration sensor 6 and input to the prediction unit 5, and the turning angular velocity ω of the host vehicle is detected by the yaw rate sensor 7 and input to the prediction unit 5.

  The prediction unit 5 uses the relative distance Rt, the relative speed Vt, the azimuth angle θt, the acceleration A, and the turning angular speed ω to the target object at the previous time point to calculate the predicted relative distance to the current target object using Equation (2). Rp, predicted relative speed Vp, and predicted azimuth angle θp are calculated. In Expression (2), tc is an observation period.

  The predicted relative distance Rp, predicted relative speed Vp, and predicted azimuth angle θp to the target object 11 calculated as described above are given to the correlation unit 3 as the predicted relative distance, relative speed, and azimuth to the current target object. Entered.

Next, the operation of the correlation unit 3 will be described.
Using the observed relative distance Ro, the observed relative speed Vo, the observed azimuth angle θo, and the predicted relative distance Rp, predicted relative speed Vp, and predicted azimuth angle θp input to the correlator 3, the error amount shown in Equation (3) e is calculated.

When the error amount e is equal to or less than the predetermined threshold Te, it is assumed that the correlation between the target track and the target object observed this time is established, and the current observation relative distance Ro, the observation relative velocity Vo, the observation direction The angle θo is input to the wake update unit 8, updated as the relative distance Rt, the relative speed Vt, and the azimuth angle θt of the wake and stored in the wake storage unit 4.
When the error amount e is larger than the predetermined threshold value Te, it is assumed that the correlation between the target track and the target object observed this time is not established, and the current observation relative distance Ro, the observation relative velocity Vo, The observation azimuth angle θo is input to the wake update unit 8, registered as a new wake, and stored in the wake storage unit 4.

  In the first embodiment, the acceleration sensor 6 and the yaw rate sensor 7 are built in the object detection apparatus. However, the acceleration A and the turning angular velocity ω are input from these sensors mounted on the host vehicle. You may comprise as follows.

  According to the first embodiment, since the predicted relative distance Rp is calculated using the acceleration A of the host vehicle speed, accurate prediction can be performed even if the host vehicle is performing acceleration / deceleration.

Embodiment 2. FIG.
The configuration of the object detection apparatus according to the second embodiment is the same as that shown in FIG.
The operation in which the radio wave subjected to frequency modulation is transmitted from the radio transmission / reception unit 1 and the observation relative distance Ro, the observation relative velocity Vo, and the observation azimuth angle θo to the target object observed this time is input to the correlation unit 3 is as follows. Since it is the same as that of Embodiment 1, the description thereof is omitted.
Further, the previous relative distance Rt, the previous relative speed Vt, the previous azimuth angle θt, the acceleration A of the host vehicle detected by the acceleration sensor 6, and the yaw rate sensor 7 of the wake stored in the wake storage unit 4 are detected. Since the operation in which the turning angular velocity ω of the host vehicle is input to the prediction unit 5 is also the same as that in the first embodiment, the description thereof is omitted.
In the second embodiment, the previous turning angular velocity ωt of the host vehicle is added to the information held by the wake.

The second embodiment will be described below.
The prediction unit 5 uses the relative distance Rt to the target object at the previous time, the relative speed Vt, the azimuth angle θt, the turning angular speed ωt, and the acceleration A and the turning angular speed ω detected this time, The predicted relative distance Rp to the target object, the predicted relative speed Vp, and the predicted azimuth angle θp are calculated. In equation (4), α is an amount corresponding to the turning angular acceleration of the host vehicle, and is calculated from the previous turning angular velocity ωt and the current turning angular velocity ω.

  The predicted relative distance Rp, predicted relative speed Vp, and predicted azimuth angle θp to the target object calculated as described above are input to the correlation unit 3 as the predicted relative distance, relative speed, and azimuth angle to the target object. Is done.

  Since the correlation unit 3 determines the correlation between the target object observed this time and the track, updates the track of the target object, and stores it in the track storage unit 4, the details are the same as in the first embodiment. The detailed explanation is omitted.

In the second embodiment, the acceleration sensor 6 and the yaw rate sensor 7 are built in the object detection device. However, as in the first embodiment, acceleration is detected from these sensors mounted on the host vehicle. You may comprise so that A and turning angular velocity (omega) may be input.

  According to the second embodiment, since the predicted azimuth angle θp is calculated in consideration of the turning angular acceleration of the host vehicle speed, it is possible to accurately predict the target object even when the turning angular velocity of the host vehicle changes. it can.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

DESCRIPTION OF SYMBOLS 1 Radio wave transmission / reception part 2 Relative position speed calculation part 3 Correlation part 4 Wake memory | storage part 5 Prediction part 6 Acceleration sensor 7 Yaw rate sensor 8 Wake update part 10 Object detection apparatus 11 Target object

Claims (1)

An object detection device that is mounted on a vehicle and periodically detects a relative distance, an azimuth angle, and a relative speed of a target object by transmitting and receiving signals,
A movement change amount acquisition unit that acquires acceleration and turning angular velocity as the movement change amount of the vehicle,
An arithmetic unit that calculates the relative distance, azimuth and relative speed of the target object based on the signal reflected from the target object;
A track storage unit that stores a track including a relative distance, an azimuth angle and a relative speed , and a turning angular velocity of the target object calculated by the calculation unit;
Based on the relative distance, azimuth angle and relative speed and turning angular velocity in the wake previously stored in the wake storage unit and using the movement change amount acquired by the movement change amount acquisition unit, the relative distance, azimuth of the wake A predictor that predicts angular and relative velocities,
The relative distance of the current calculated target object by the arithmetic unit, the azimuth and the relative speed, relative distance predicted by the prediction unit, azimuth and based on the relative velocity, this calculated target object and the previous track A correlation unit for determining whether or not there is a correlation between
If there is a correlation in the determination by the correlation unit, the wake is updated based on the relative distance, azimuth angle and relative speed and turning angular velocity of the target object calculated this time. As a wake, provided with a wake update unit for storing the relative distance, azimuth and relative speed and turning angular velocity of the target object calculated this time in the wake storage unit ,
The movement change amount acquisition unit calculates a turning angular acceleration of the vehicle using a turning angular velocity stored in the wake,
The prediction unit uses the turning angular acceleration of the vehicle for the prediction of the azimuth angle .

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