JP5034966B2 - Object speed detector - Google Patents

Description

  The present invention relates to an object speed detection device that detects a moving speed of an object such as a vehicle.

As a conventional object speed detection device, for example, as described in Patent Document 1, position observation data of a moving body that is an obstacle to traveling of the host vehicle is input, and the speed of the moving body is calculated based on a linear motion model. A device that calculates the speed of a moving body that becomes an obstacle using an estimated Kalman filter is known.
JP-A-8-122432

  In the above prior art, the speed of the moving body can be calculated from the position observation data of the moving body. However, when the object speed detection device is applied to a PCS (pre-crash safety system) or the like that requires a short sampling period, a slight positional deviation greatly affects the speed calculation result. By using the Kalman filter, variations in position to some extent are suppressed, but there is a problem that the time until convergence becomes longer depending on how the initial values are given. For this reason, there is a limit in calculating the speed of the moving object only from the position information.

  An object of the present invention is to provide an object speed detection device capable of obtaining a moving speed of an object with high accuracy.

  The present invention relates to an object speed detection device that is mounted on a moving body and detects a moving speed of an object, a position information acquisition unit that acquires position information of the object, and a movement of the object based on the position information of the object. Using the speed calculation means for calculating the speed, the relative speed information acquisition means for acquiring the relative speed information between the moving object and the object, and the relative speed information, the upper limit value and the lower limit value of the movement speed of the object are calculated. And a speed limit value calculating means.

  In such an object speed detection device of the present invention, by acquiring the relative speed information of the moving body and the object, by using the relative speed information to obtain the upper limit value and the lower limit value of the moving speed of the object, Variations in the moving speed of the object obtained based on the position information of the object can be suppressed. Thereby, compared with the case where the moving speed of a target object is calculated | required only based on the positional information on a target object, the moving speed of the target object which approaches a mobile body can be calculated | required with high precision.

  Preferably, a means for obtaining an approach direction vector of the object relative to the moving object based on the position information of the object, and a means for obtaining an approach direction area of the object based on the approach direction vector and a preset correction angle. The speed limit value calculating means calculates an upper limit value and a lower limit value of the moving speed of the object based on the approach direction region of the object and the relative speed information.

  If there is a predetermined number of pieces of position information of the target object, it is possible to predict an approach direction vector of the target object with respect to the moving object from each position information. Therefore, an approach direction area of the object is obtained based on the approach direction vector of the object with respect to the moving object and a preset correction angle, and an upper limit of the moving speed of the object is determined based on the approach direction area and the relative speed information. By obtaining the value and the lower limit value, it is possible to obtain an appropriate upper limit value and lower limit value of the moving speed according to the approach direction of the object. Thereby, the moving speed of the target object approaching the moving body can be obtained with higher accuracy.

  Preferably, the apparatus further comprises means for determining whether the effective score of the position information of the object acquired by the position information acquiring means is two or more and less than a predetermined number, and the speed limit value calculating means includes the target When the effective point number of the object position information is two or more and less than the predetermined number, the upper limit value and the lower limit value of the moving speed of the object are determined based on the two preset direction data and the relative speed information. calculate.

  If there are at least two effective points in the position information of the object, it is possible to obtain the upper limit value and the lower limit value of the moving speed of the object based on the two direction data and the relative speed information. In this case, the moving speed of the object approaching the moving body can be easily obtained with high accuracy.

  The present invention also provides a position information acquisition means for acquiring position information of an object from radar measurement data, in an object speed detection device mounted on a moving body and detecting the moving speed of the object using a radar, First speed calculating means for calculating a first moving speed of the object based on position information of the object, relative speed information acquiring means for acquiring relative speed information of the moving object and the object from the radar measurement data, A second speed calculating means for calculating a second moving speed of the object based on the speed information; a first moving speed calculated by the first speed calculating means; a second moving speed calculated by the second speed calculating means; And a speed determining means for determining the moving speed of the object.

  In such an object speed detection device of the present invention, the first moving speed of the target object is calculated based on the position information of the target object, and the first speed of the target object is calculated based on the relative speed information between the moving body and the target object. By calculating the two moving speeds and obtaining the moving speed of the object based on the first moving speed and the second moving speed, it is possible to obtain a moving speed that enjoys the merits of both calculation methods. Thereby, compared with the case where the moving speed of a target object is calculated | required only based on the positional information on a target object, the moving speed of the target object which approaches a mobile body can be calculated | required with high precision.

  Preferably, the apparatus further includes means for obtaining an approach direction vector of the object with respect to the moving object based on the position information of the object, and the speed determination means determines the degree of divergence between the approach direction vector of the object and the measurement radial direction of the radar. Based on this, the weighting of the first moving speed and the second moving speed is determined, and the moving speed of the object is obtained.

  When calculating the second moving speed of the target object based on the relative speed information between the moving object and the target object, the calculation accuracy improves as the approaching direction of the target object becomes closer to the measurement radius direction of the radar. Therefore, by determining the weighting of the first moving speed and the second moving speed based on the degree of deviation between the approaching direction vector of the object and the measurement radial direction of the radar, the moving speed of the object approaching the moving body is determined. It can be determined with higher accuracy.

  According to the present invention, the moving speed of an object can be obtained with high accuracy. This makes it possible to make a collision determination with high accuracy when, for example, a process for determining whether or not the mobile object and the object collide is performed in the subsequent process.

  Preferred embodiments of an object speed detection device according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an object velocity detection apparatus according to the present invention. In the figure, an object speed detection device 1 of the present embodiment is applied to, for example, a PCS (pre-crash safety system) mounted on a vehicle.

  The object speed detection device 1 includes a millimeter wave radar 2, a wheel speed sensor 3, and a speed calculation ECU (Electronic Control Unit) 4 connected to the millimeter wave radar 2 and the wheel speed sensor 3.

  The millimeter wave radar 2 applies a millimeter wave (for example, 76 GHz to 77 GHz) to a partner vehicle approaching the host vehicle, receives the millimeter wave reflected from the partner vehicle, and generates a frequency caused by a propagation time or a Doppler effect. It is a sensor for measuring the position of the opponent vehicle and the relative speed with the own vehicle from the difference. The wheel speed sensor 3 detects the rotational speed of each wheel as a pulse signal.

  The speed calculation ECU 4 includes a partner vehicle position calculation unit 5, a relative speed calculation unit 6, a partner vehicle track calculation unit 7, a host vehicle speed calculation unit 8, and a partner vehicle speed calculation unit 9. A collision determination ECU 10 is connected to such speed calculation ECU 4.

  The opponent vehicle position calculation unit 5 calculates the position of the opponent vehicle with respect to the own vehicle from the measurement data of the millimeter wave radar 2. The relative speed calculation unit 6 calculates the relative speed between the host vehicle and the opponent vehicle from the measurement data of the millimeter wave radar 2. The partner vehicle track calculation unit 7 calculates the track (direction of approach) of the partner vehicle from the history of the position information of the partner vehicle using a least square method or the like. The own vehicle speed calculation unit 8 calculates the vehicle speed of the own vehicle from the detection value of the wheel speed sensor 3. The partner vehicle speed calculation unit 9 obtains the vehicle speed (traveling speed) of the partner vehicle based on the position of the partner vehicle, the relative speed between the host vehicle and the partner vehicle, the track of the partner vehicle, and the vehicle speed of the host vehicle.

  Various calculation data obtained by the speed calculation ECU 4 are sent to the collision determination ECU 10. Then, the collision determination ECU 10 determines the possibility of collision between the own vehicle and the opponent vehicle based on various calculation data.

  FIG. 2 is a flowchart showing a procedure of a partner vehicle speed calculation process executed by the partner vehicle speed calculation unit 9.

  In the figure, first, target (here, a partner vehicle approaching the own vehicle) information from the millimeter wave radar 2 is acquired (step S101). Specifically, the position of the partner vehicle calculated by the partner vehicle position calculation unit 5, the relative speed between the host vehicle and the partner vehicle calculated by the relative speed calculation unit 6, and the track of the partner vehicle calculated by the partner vehicle track calculation unit 7. Get information about.

  Subsequently, it is determined whether or not the number of effective points of the target information from the millimeter wave radar 2 is 2 or more (step S102). Here, the effective score of the target information represents the history score of the target stably captured by the millimeter wave radar 2 except during extrapolation.

  When the number of effective points of the target information is 2 or more, is the number of effective points of the target information from the millimeter wave radar 2 is 5 or more, or has the procedures S108 and S109 described later been executed in the previous processing? It is determined whether or not (step S103).

  When the effective score of the target information is a predetermined score (here, 5 points) or more, or when steps S108 and S109 described later in the previous processing are executed, the position of the opponent vehicle obtained by the opponent vehicle position calculation unit 5 By performing position differentiation using the αβ filter, which is an existing method, information is converted from the capture point of the millimeter wave radar 2 to a fixed ground coordinate axis, and the vehicle speed of the opponent vehicle is calculated while suppressing variation in position (procedure) S104).

  FIG. 3 shows the concept of calculating the vehicle speed of the opponent vehicle by performing position differentiation using an αβ filter. In the figure, first, a predicted point of an opponent vehicle is obtained by an αβ filter equation. Then, the distance between the predicted point and the capture point (millimeter wave radar information) is considered at a ratio of 1, and the section is divided at a ratio of 1-α: α to obtain a smooth point. This smooth point is taken as the position of the partner vehicle at the time k.

The prediction points (X _p (k), Y _p (k)) are updated as follows.
_{X p (k) = X s} (k-1) + TV sx (k-1)
Y _p (k) = Y _s (k−1) + TV _sy (k−1)

The smooth points (X _s (k), Y _s (k)) are updated as follows. X _m (j) and Y _m (j) are values of the capture points.
_{X s (k) = X p} (k) + α [X m (j) -X p (k)]
Y _s (k) = Y _p (k) + α [Y _m (j) −Y _p (k)]

However, X _s (0), Y _s (0), V _sx (0), and V _sy (0) required at the first time are defined as follows.
X _s (0) = X _m (4)
Y _s (0) = Y _m (4)
V _sx (0) = V _nx
V _sy (0) = V _ny

The current smoothing speed is obtained by correcting the residual between the predicted point and the captured point by the ratio of β to the previously calculated smoothing speed. Then, the vehicle speed V _{nxy of the} opponent vehicle is calculated from the smooth speeds in these directions. V _sx (k) and V _sy (k) are smoothing speeds at time k, and T is a sampling interval at the effective point.
V _nx = V _sx (k) = V _sx (k−1) + β [X _m (j) −X _p (k)] / T
V _ny = V _sy (k) = V _sy (k−1) + β [Y _m (j) −Y _p (k)] / T

Here, the tuning of the αβ filter is performed with coefficients (filter constants) α, β. The meanings of the coefficients α and β are as follows.
α: Coefficient related to the weighted average of the current prediction point and capture point
The closer to 0, the greater the weight of the prediction point, and the closer to 1, the greater the weight of the capture point. Β: Based on the previous smoothing speed, add the speed increase according to the residual between the capture point and the prediction point Coefficient
The closer to 0, the previous smoothing speed is maintained, and the smoothing speed changes according to the residual between the capture point and the prediction point.

The values of the coefficients α and β are determined as follows, for example.

  Next, a speed upper / lower limit cut filter based on the predicted predicted trajectory of the opponent vehicle obtained by the opponent vehicle trajectory calculation unit 7 is applied to the estimated speed of the opponent vehicle obtained in step S104 (procedure S105).

4 and 5 show the concept of the speed upper / lower limit cut filter based on the opponent vehicle predicted trajectory. In each figure, in this procedure, the predicted trajectory (approach direction vector M) of the companion vehicle B obtained by the companion vehicle trajectory calculation unit 7 and constant correction angles ξ _{L +} and ξ _L− with respect to the approach direction vector M are obtained. The range (approach direction area) H in the approach direction of the partner vehicle B is obtained. Further, the vehicle speed of the host vehicle A (hereinafter simply referred to as the host vehicle speed) v ₀ obtained by the host vehicle speed calculation unit 8, and the relative speed of the host vehicle A and the partner vehicle B obtained by the relative speed calculation unit 6 (hereinafter simply referred to as relative V _r ), the angle (line-of-sight angle) ξ formed by the host vehicle speed v ₀ and the relative speed v _r , the angle formed by the approach direction vector M of the partner vehicle B and the host vehicle speed v ₀ , that is, the host vehicle A and the partner vehicle When it is assumed that B collides, the upper and lower limit values of the speed of the opponent vehicle B are calculated from the angle δ immediately before the collision between them (the angle immediately before the collision) δ.

Specifically, the opponent vehicle component v _A of the relative speed v _r is determined as the speed lower limit value v _nxy− of the opponent vehicle B. However, the speed lower limit value v _nxy− is, for example, the lowest value 0 km / h.
v _nxy− = v _A = −v _r −v _I = −v _r −v ₀ cos | ξ |

The relative velocity _v with the mating wheel component _{v A} of _r collision immediately prior angle δ correction angle xi] _{L +,} from xi] _L-and determines the speed upper limit of the counterpart vehicle B _{v NXY +.}

However, in order to prevent division by zero, | δ− | ξ || + ξ _{L +} <π / 2 or | δ− | ξ || + ξ _L− <π / 2, and the predicted trajectory line is formal and the angle immediately before the collision. When δ is calculated, the above calculation formula is used. In other cases, the speed upper limit value v _{nxy + is set} to 180 km / h, for example. When the speed upper limit value v _{nxy +} is, for example, 15 km / h or less, the speed upper limit value v _{nxy + is set} to 15 km / h. The correction angle ξ _{L +} is, for example, 60 °, and the correction angle ξ _L− is, for example, 0 °.

のままとする。 The vehicle speed V _nxy of the partner vehicle B based on the position information of the partner vehicle B is determined using the partner vehicle speed lower limit value v _nxy− and the speed upper limit value v _{nxy +} thus obtained.
When V _nxy <v _nxy− ,
Correction of smoothing speed in each direction: V _nx ′ = v _nxy− × V _nx / V _nxy
V _ny ′ = v _nxy− × V _ny / V _nxy
Update of estimated speed: V _nxy = v _nxy−
When V _nxy > v _{nxy +} ,
Correction of smoothing speed in each direction: V _nx ′ = v _{nxy +} × V _nx / V _nxy
V _ny ′ = v _{nxy +} × V _ny / V _nxy
Update of estimated speed: V _nxy = v _{nxy +}
When v _nxy− ≦ V _nxy ≦ v _{nxy +} ,

Leave as it is.

Next, a speed v _nr of the opponent vehicle based on the Doppler relative speed information is calculated separately from the vehicle speed V _{nxy of the} opponent vehicle based on the position information of the opponent vehicle (step S106).

FIG. 6 shows the concept of obtaining the speed of the opponent vehicle from the relative speed information. In this figure, in this procedure, the speed v _nr of the opponent vehicle based on the relative speed information is calculated from the relative speed v _r , the host vehicle speed v ₀ , the line-of-sight angle ξ, and the angle just before the collision δ using the following formula.

However, in order to prevent the division by zero, when | δ− | ξ || <π / 2 and the angle δ immediately before the collision is calculated, the above formula is used. The velocity v _nr is not calculated.

Next, the vehicle speed V _{nxy of the} opponent vehicle obtained from the position information in steps S104 and S105 and the vehicle speed v _{nr of the} opponent vehicle obtained from the relative speed information in step S106 are combined to obtain the final vehicle speed v of the opponent vehicle. _n is calculated, and the process proceeds to step S110 (step S107).

Specifically, it calculates the vehicle speed v _n of the counterpart vehicle using the following equation.
v _n = (1−A _p ) v _nr + A _p · V _nxy
A _p (0 ≦ A _p ≦ 1) is a vehicle speed mixing ratio. Weight of the vehicle speed calculated from the position information of the higher counterpart vehicle A _p increases increases, the weight of the vehicle speed calculated from the relative velocity information about A _p decreases increases.

  Here, when the speed vector of the partner vehicle B is in the direction on the mounting center axis of the millimeter wave radar 2, that is, in the vicinity of the millimeter wave measurement direction (| δ− | ξ || = 0), the millimeter wave radar 2 The relative speed can be detected with high accuracy. However, when the speed vector of the partner vehicle B is in a direction different from the center axis of the millimeter wave radar 2 attached, the speed component perpendicular to the central axis, that is, the speed component that cannot be seen by the Doppler increases. The relative speed detection accuracy due to 2 becomes worse.

Therefore, for example, using a map as shown in Table 1, | δ- | ξ || value sought A _{p 'from,} seek A _p by the linear interpolation. However, when the vehicle speed _{v nr} is not calculated, _{if A p} exceeds 1 and 1 a _{A p.}

  In the above step S103, when the effective score of the target information is not 5 points or more but 2 points or more and less than 5 points, and steps S108 and S109 are not executed in the previous process, the opponent vehicle position calculation unit 5 The vehicle speed of the opponent vehicle is calculated by performing general position differentiation without using the αβ filter with respect to the position information of the opponent vehicle obtained in step S108.

Specifically, the acquisition point of the millimeter wave radar 2 is converted to a fixed ground coordinate axis, the distance between the oldest acquisition point and the newest acquisition point in time series is divided by the interval time, and the speed in each direction is obtained. The vehicle speed V _{nxy of the} opponent vehicle is calculated from the speed of the vehicle. X _m (j) and Y _m (j) are values of the capture points, and T is a sampling interval at the effective point.
V _nx (j) = [X _m (j) −X _m (1)] / T
V _ny (j) = [Y _m (j) −Y _m (1)] / T

  Next, a speed upper / lower limit cut filter in the horizontal and vertical directions set in advance is applied to the estimated speed of the opponent vehicle obtained in step S108, and the process proceeds to step S110 (step S109).

  The concept of the upper and lower speed cut filters in the horizontal and vertical directions is shown in FIGS. In each figure, the vertical direction is the traveling direction of the host vehicle, and the horizontal direction is the direction perpendicular to the traveling direction of the host vehicle. However, the method of determining the horizontal and vertical directions is not limited to this.

In this procedure, first, an approach direction range (approach direction region) H of the partner vehicle B is assumed using a constant correction angle ξ _h with respect to the horizontal direction and a constant correction angle ξ _v with respect to the vertical direction. Then, a filter value is calculated from the host vehicle speed v ₀ , relative speed v _r , and line-of-sight angle ξ, and upper and lower limit values of the speed of the partner vehicle B are calculated.

Specifically, the speed lower limit value v _nxy− of the opponent vehicle B is determined as follows. However, the speed lower limit value v _nxy− is, for example, the lowest value 0 km / h.
v _nxy− = −v _r −v _I = −v _r −v ₀ cos | ξ | = v _A

The speed upper limit value _{vnxy +} of the partner vehicle B is determined as follows.

However, in order to prevent division by zero, the above formula is used when 2 / π− | ξ | + ξ _h <π / 2 or | ξ | + ξ _v <π / 2, and in other cases, the upper speed limit For example, v _{nxy + is set} to 180 km / h. When the speed upper limit value v _{nxy +} is, for example, 15 km / h or less, the speed upper limit value v _{nxy + is set} to 15 km / h. The correction angle ξ _h is 5 °, for example, and the correction angle ξ _v is 0 °, for example.

のままとする。 The vehicle speed V _nxy of the opponent vehicle B is determined using the speed lower limit value v _nxy− and the speed upper limit value v _{nxy +} of the opponent vehicle B _thus obtained.
When V _nxy <v _nxy− ,
Correction of speed in each direction: V _nx ′ = v _nxy− × V _nx / V _nxy
V _ny ′ = v _nxy− × V _ny / V _nxy
Update of estimated speed: V _nxy = v _nxy−
When V _nxy > v _{nxy +} ,
Correction of speed in each direction: V _nx ′ = v _{nxy +} × V _nx / V _nxy
V _ny ′ = v _{nxy +} × V _ny / V _nxy
Update of estimated speed: V _nxy = v _{nxy +}
When v _nxy− ≦ V _nxy ≦ v _{nxy +} ,

Leave as it is.

Then, the vehicle speed _{V NXY} in which the calculated vehicle speed _{v n} of the opponent car B.
v _n = V _nxy

In step S110, transmits the data of the vehicle speed _{v n} obtained opponent car in Step S107 or Step S109 to the collision determination ECU 10.

Further, in the above step S102, when it is determined that the number of effective points of the target information from the millimeter wave radar 2 is less than 2, the number of effective points is extremely small, and in principle, the vehicle speed of the opponent vehicle is obtained. can not, and sends the invalid value data to the collision determination ECU10 as a vehicle speed _{v n} of the opponent vehicle (Step S111).

  In the above, the procedure S101 of the millimeter wave radar 2, the opponent vehicle position calculation unit 5, and the opponent vehicle speed calculation unit 9 constitutes a position information acquisition unit that acquires the position information of the object. Steps S104 and S108 of the counterpart vehicle speed calculation unit 9 constitute speed calculation means for calculating the moving speed of the object based on the position information of the object. The procedure S101 of the millimeter wave radar 2, the relative speed calculation unit 6, and the counterpart vehicle speed calculation unit 9 constitutes a relative speed information acquisition unit that acquires relative speed information between the moving object and the object. Steps S105 and S109 of the host vehicle speed calculation unit 8 and the partner vehicle speed calculation unit 9 constitute speed limit value calculation means for calculating the upper limit value and the lower limit value of the moving speed of the object using the relative speed information.

  The counterpart vehicle track calculation unit 7 constitutes means for obtaining an approaching direction vector of the object relative to the moving body based on the position information of the object. Steps S101 and S105 of the counterpart vehicle speed calculation unit 9 constitute a means for obtaining the approach direction region of the object based on the approach direction vector and a preset correction angle.

  Steps S102 and S103 of the counterpart vehicle speed calculation unit 9 constitute means for determining whether the effective position number of the position information of the object acquired by the position information acquisition means is 2 or more and less than a predetermined number.

  The procedure S101 of the opponent vehicle position calculation unit 5 and the opponent vehicle speed calculation unit 9 constitutes position information acquisition means for acquiring the position information of the object from the measurement data of the radar 2. Steps S104 and S105 of the host vehicle speed calculation unit 8 and the partner vehicle speed calculation unit 9 constitute first speed calculation means for calculating the first moving speed of the target object based on the position information of the target object. Step S101 of the relative speed calculation unit 6 and the counterpart vehicle speed calculation unit 9 constitutes a relative speed information acquisition unit that acquires relative speed information between the moving body and the target object from the measurement data of the radar 2. Step S106 of the own vehicle speed calculation unit 8 and the counterpart vehicle speed calculation unit 9 constitutes a second speed calculation unit that calculates the second movement speed of the object based on the relative speed information. Step S107 of the counterpart vehicle speed calculation unit 9 is a speed at which the moving speed of the object is determined based on the first moving speed calculated by the first speed calculating means and the second moving speed calculated by the second speed calculating means. The determination means is configured.

  By the way, the traveling speed of the opponent vehicle can be calculated by differentiating the position information of the opponent vehicle obtained from the millimeter wave radar 2. However, since the calculation cycle in the PCS is as short as 16 ms, the calculation result of the running speed of the opponent vehicle varies greatly due to a slight shift in the position information of the opponent vehicle.

On the other hand, in this embodiment, focusing on the fact that the approaching direction of the opponent vehicle can be predicted from the history of the position information of the opponent vehicle when the number of effective millimeter wave capture points by the millimeter wave radar 2 is large. When the number of effective points of the vehicle position information is 5 or more, after performing position differentiation using the αβ filter to calculate the vehicle speed V _nxy of the opponent vehicle, the approach direction of the opponent vehicle from the history of each position information of the opponent vehicle Find a vector. And the approach direction area | region of an other party vehicle is calculated | required using the approach direction vector and correction | amendment angle of the other party vehicle. Then, using the relative speed information of the opponent vehicle with respect to the own vehicle and the approach direction area of the opponent vehicle, the upper limit speed value and the lower limit speed value of the opponent vehicle are obtained, and the vehicle speed V of the opponent vehicle obtained by position differentiation as necessary. _nxy is corrected. Thereby, the dispersion | variation in the vehicle speed data of the other party vehicle calculated only from the position information of the other party vehicle can be suppressed.

In addition to the vehicle speed V _{nxy of the} opponent vehicle obtained from the position information of the opponent vehicle, the vehicle speed v _{nr of the} opponent vehicle is obtained from the relative speed information of the opponent vehicle with respect to the own vehicle. Here, in the method of obtaining the vehicle speed only from the position information, the speed can be calculated stably regardless of the approaching direction of the opponent vehicle, but the variation is large as a whole. On the other hand, in the method of obtaining the vehicle speed only from the relative speed information, the approaching direction vector of the opponent vehicle can be calculated with high accuracy when the vector is close to the measurement radial direction (millimeter wave measurement direction) of the millimeter wave radar 2, but the opponent vehicle When the approaching direction vector becomes far from the measurement radial direction of the millimeter wave radar 2, the calculation accuracy is deteriorated.

In this embodiment, the vehicle speed V _{nxy of the} opponent vehicle obtained from the position information and the vehicle speed v _{nr of the} opponent vehicle obtained from the relative speed information are combined, and the measurement radial direction of the millimeter wave radar 2 with respect to the approach direction vector of the opponent vehicle Since the mixing ratio (weighting) of both is changed according to the degree of divergence of the vehicle, the vehicle speed of the opponent vehicle can be calculated with higher accuracy by taking advantage of the vehicle speed calculation method of both.

On the other hand, when the millimeter wave radar 2 has a small number of millimeter wave capture effective points, the approach direction of the partner vehicle cannot be predicted from the history of the partner vehicle position information, but it can be understood that the partner vehicle is approaching itself. . Therefore, when the number of effective points in the position information of the opponent vehicle is 2 or more and less than 5, the position vehicle is calculated by calculating the vehicle speed V _{nxy of the} opponent vehicle using the position differential, and then using the correction angle with respect to the horizontal and vertical directions. Assuming the approach direction area of the vehicle, use the relative speed information of the partner vehicle with respect to the host vehicle and the approach direction region of the partner vehicle to obtain the speed upper limit value and speed lower limit value of the partner vehicle, and obtain it by position differentiation as necessary. The vehicle speed V _nxy of the other vehicle is corrected. Also in this case, it is possible to suppress variations in the vehicle speed data of the opponent vehicle calculated from only the position information of the opponent vehicle.

  As described above, according to the present embodiment, the travel speed of the partner vehicle is calculated by calculating the travel speed of the partner vehicle using both the position information of the partner vehicle and the relative speed information of the partner vehicle with respect to the host vehicle. It can be detected with high accuracy. As a result, the collision determination ECU 10 can accurately determine the collision between the host vehicle and the opponent vehicle.

  Next, since the experiment which estimates the vehicle speed of the other party vehicle using the vehicle speed calculation logic mentioned above was performed, the content is demonstrated. Here, as shown in FIG. 9, a test pattern in which the host vehicle A and the partner vehicle B travel at 40 km / h in the perpendicular direction is adopted.

  FIG. 10 shows the estimation result of the speed of the opponent vehicle. In FIG. 10, the horizontal axis of the graph represents TTC (Time to Collision), and the vertical axis of the graph represents an estimated value of the speed of the opponent vehicle. Black diamonds P in the table represent vehicle speed calculation results by normal position differentiation (position differentiation without using an αβ filter), and black squares Q in the table represent vehicle speed calculation by position differentiation using an αβ filter. The white triangle mark R in the table represents the vehicle speed calculation result when the upper / lower limit cut filter is applied to the vehicle speed obtained by the position differentiation using the αβ filter, and the * mark S in the table represents The vehicle speed calculation result when the vehicle speed obtained by applying the above-mentioned upper and lower limit cut filter and the vehicle speed obtained from the relative speed information is combined is shown. The solid line T represents the actual vehicle speed (40 km / h). In addition, the numerical value mentioned above was used as it is as a parameter conformity value for vehicle speed estimation.

  As is clear from the estimation results shown in FIG. 10, as the position differential using the αβ filter, the upper / lower limit cut filter, and the combination of the vehicle speed obtained from the position information and the vehicle speed obtained from the relative speed information are adopted. The estimation accuracy of the speed of the opponent vehicle is higher. Therefore, the effectiveness of the present invention has been demonstrated.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the position information and relative speed information of the opponent vehicle are acquired using the millimeter wave radar 2, but the radar to be used is not limited to the millimeter wave radar, and is a laser radar or the like. Also good.

  Further, in the above embodiment, the vehicle speed obtained by applying the speed upper / lower limit cut filter by the opponent vehicle predicted trajectory and the vehicle speed obtained from the relative speed information are combined to obtain the final vehicle speed of the opponent vehicle. However, it is also possible to obtain the final vehicle speed of the opponent vehicle by combining the vehicle speed obtained by applying the speed upper / lower limit cut filter in the horizontal and vertical directions and the vehicle speed obtained from the relative speed information.

  Furthermore, although the said embodiment is applied to PCS, the object speed detection apparatus of this invention is applicable also to systems other than PCS. The object speed detection device of the present invention can also be applied to detection of moving objects other than vehicles such as automobiles.

It is a block diagram which shows schematic structure of one Embodiment of the object speed detection apparatus concerning this invention. It is a flowchart which shows the procedure of the calculation process of the other party vehicle speed performed by the other party vehicle speed calculating part shown in FIG. It is a conceptual diagram which shows the view which calculates the vehicle speed of the other party vehicle by performing position differentiation using an αβ filter. It is a conceptual diagram which shows the idea of the speed upper / lower limit cut filter by the other party vehicle prediction track. It is a conceptual diagram which shows the idea of the speed upper / lower limit cut filter by the other party vehicle prediction track. It is a conceptual diagram which shows the view which calculates | requires the vehicle speed of an other party vehicle from relative speed information. It is a conceptual diagram which shows the view of the speed upper / lower limit cut filter by a horizontal / vertical direction. It is a conceptual diagram which shows the view of the speed upper / lower limit cut filter by a horizontal / vertical direction. It is a figure which shows the test pattern which estimates the vehicle speed of an other party vehicle. It is a graph which shows the result of having estimated the vehicle speed of the other party vehicle by the test pattern shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Object speed detection apparatus, 2 ... Millimeter wave radar (position information acquisition means, relative speed information acquisition means), 4 ... Speed calculation ECU, 5 ... Counterpart vehicle position calculating part (position information acquisition means), 6 ... Relative speed calculation Parts (relative speed information acquisition means), 7 ... counterpart vehicle track calculation part, 8 ... own vehicle speed calculation part (speed limit value calculation means, first speed calculation means, second speed calculation means), 9 ... counterpart vehicle speed calculation part ( Position information acquisition means, speed calculation means, relative speed information acquisition means, speed limit value calculation means, first speed calculation means, second speed calculation means, speed determination means), A ... own vehicle (moving body), B ... partner Car (object).

Claims (5)

In an object speed detection device that is mounted on a moving body and detects the moving speed of an object,
Position information acquisition means for acquiring position information of the object;
Speed calculating means for calculating a moving speed of the object based on position information of the object;
Relative speed information acquisition means for acquiring relative speed information between the moving object and the object;
An object speed detection device comprising: speed limit value calculation means for calculating an upper limit value and a lower limit value of the moving speed of the object using the relative speed information. Means for obtaining an approaching direction vector of the object relative to the moving body based on position information of the object;
Means for obtaining an approach direction region of the object based on the approach direction vector and a preset correction angle;
The said speed limit value calculation means calculates the upper limit value and lower limit value of the moving speed of the target object based on the approach direction area of the target object and the relative speed information. Object speed detection device. A means for determining whether or not the number of effective points of the position information of the object acquired by the position information acquisition means is two or more and less than a predetermined number;
When the effective point number of the position information of the object is 2 points or more and less than a predetermined number, the speed limit value calculating unit is configured to calculate the speed limit value based on the two direction data set in advance and the relative speed information. 3. The object speed detection device according to claim 1, wherein an upper limit value and a lower limit value of the moving speed of the object are calculated. In an object speed detection device that is mounted on a moving body and detects the moving speed of an object using a radar,
Position information acquisition means for acquiring position information of the object from the measurement data of the radar;
First speed calculating means for calculating a first moving speed of the object based on position information of the object;
Relative velocity information acquisition means for acquiring relative velocity information between the moving body and the object from the radar measurement data;
Second speed calculating means for calculating a second moving speed of the object based on the relative speed information;
Speed determining means for determining the moving speed of the object based on the first moving speed calculated by the first speed calculating means and the second moving speed calculated by the second speed calculating means. Characteristic object speed detection device. Means for obtaining an approach direction vector of the object relative to the moving object based on position information of the object;
The speed determining means determines the weighting of the first moving speed and the second moving speed based on a degree of deviation between the approach direction vector of the object and the measurement radial direction of the radar, and moves the object 5. The object speed detection apparatus according to claim 4, wherein the speed is obtained.

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