JP5166751B2 - Automotive radar equipment - Google Patents

Description

  The present invention relates to an in-vehicle radar device suitable for an ACC (Adaptive Cruise Control) system.

In the ACC system, a function (follow-up control) for controlling the driving force and braking force of the host vehicle is set so as to maintain a predetermined inter-vehicle distance with respect to the preceding vehicle, and it is mounted on the vehicle for capturing the preceding vehicle and measuring the inter-vehicle distance. A radar device is used. In Patent Document 1, an apparatus for detecting an inter-vehicle distance from the own vehicle to a preceding vehicle using an in-vehicle radar device is disclosed.
Japanese Patent No. 3089864

  For in-vehicle radar devices suitable for the ACC system, in order to improve the catchability of the preceding vehicle, a means for estimating the curvature of the own vehicle traveling path from the vehicle speed and yaw rate of the own vehicle and the lane width of the own vehicle traveling path are set. Means for setting the lane shape of the own vehicle traveling path from the curvature and lane width of the own vehicle traveling path, and means for determining the nearest preceding vehicle on the lane shape as a preceding vehicle to be maintained at a predetermined inter-vehicle distance (Japanese Patent Application No. 2006-79066).

  In such an on-vehicle radar device, if the accuracy of estimating the curvature of the own vehicle traveling path is not sufficiently ensured, the preceding vehicle to be followed by the own vehicle on the S-curve or the like may be lost or the adjacent oncoming vehicle may be It can be mistaken for a preceding vehicle, and the following control may cause unnecessary acceleration and deceleration to be repeated.

  An object of this invention is to provide an effective means for solving such a problem.

According to a first aspect of the present invention, there is provided a yaw rate sensor for detecting a yaw rate of the own vehicle, a means for detecting a vehicle speed of the own vehicle, and a curvature estimation for estimating a curvature of the own vehicle traveling path based on a yaw rate detection signal and a vehicle speed detection signal. Means for setting the lane width of the own vehicle traveling path, means for setting the lane shape of the own vehicle traveling path from the estimated curvature estimated by the curvature estimating means and the lane width, and detection of the yaw rate sensor A yaw rate correction means for correcting an error, wherein the yaw rate correction means sets a gain corresponding to the reciprocal of the estimated curvature as a parameter, a detected value of yaw rate = the gain × the output of the yaw rate sensor Means for correcting to a value, wherein the gain is set to a larger value as the reciprocal of the estimated curvature becomes smaller .

According to a second aspect of the invention, a yaw rate sensor for detecting the yaw rate of the own vehicle, a means for detecting the vehicle speed of the own vehicle, a first filter for removing noise included in a detection signal of the yaw rate sensor, and after the first filter processing The first curvature estimation means for estimating the curvature of the own vehicle traveling path from the yaw rate of the vehicle and the detection signal of the vehicle speed, the means for setting the lane width of the own vehicle traveling path, and the curvature estimated by the first curvature estimation means And means for setting the lane shape of the own vehicle traveling path from the lane width, a second filter for removing noise included in the yaw rate detection signal, and means for calculating the fluctuation of the yaw rate after the second filter processing Secondly, the curvature of the vehicle traveling path is estimated from the means for adjusting the time constant of the first filter based on the fluctuation, the yaw rate after the second filter processing, and the vehicle speed detection signal. Comprising a rate estimation means, and a yaw rate correcting means for correcting the detection error of the yaw rate sensor based on the curvature estimated by the second curvature estimating means, said yaw rate compensation means, estimated by the second curvature estimating means Means for setting a gain corresponding to the reciprocal of the calculated curvature as a parameter, and means for correcting the detected value of the yaw rate = the gain × the output value of the yaw rate sensor. It is characterized by being set to a larger value as the reciprocal becomes smaller .

  In the first to third inventions, the detection error of the yaw rate sensor is corrected, and the curvature of the own vehicle traveling path is estimated using the corrected yaw rate detection signal. The detection error of the yaw rate sensor includes a physical operation delay (response delay). Therefore, when the vehicle is traveling straight ahead, the detection error that can be confused with noise (high-frequency components due to engine vibration, etc.) , Get bigger with this. By removing the error, the preceding vehicle can be captured accurately even on an S-shaped curve or the like.

  In the second invention or the third invention, it is possible to determine the fluctuation of the yaw rate with high sensitivity by the second filter. For this reason, the adjustment (correction) of the time constant of the first filter is advanced, and the curvature of the own vehicle traveling path can be appropriately estimated from the yaw rate after the first filter processing and the vehicle speed detection signal. In the case of only the first filter, it is difficult to set the time constant when traveling straight. In other words, the second filter can minimize the response delay while determining the yaw rate variation with high sensitivity in the first filter. The response delay of the second filter is corrected together with the detection error of the yaw rate sensor. Accordingly, the curvature of the own vehicle traveling path can be accurately estimated even in an S-shaped curve or the like.

  In FIG. 1, reference numeral 10 denotes an electronic control unit (ACC-ECU) of an ACC system mounted on a truck, which controls the braking / driving force of the vehicle so as to maintain the actual inter-vehicle distance with the preceding vehicle. A distance control system 11 (following travel control system) is provided. Reference numeral 12 denotes an operation system of the ACC system 10 in which various function switches are arranged in addition to the main switch. Reference numeral 13 denotes a display system of the ACC system, which displays various ACC information. Reference numeral 14 denotes an inter-vehicle warning buzzer.

  15 is an engine electronic control unit (engine-ECU), 16 is a retarder electronic control unit (retarder-ECU), 17 is a transmission electronic control unit (T / M-ECU), and 18 is a front An inter-vehicle distance radar device that detects an actual inter-vehicle distance from a vehicle, 19 is a yaw rate sensor that detects an angular velocity (yaw rate) around the center of gravity of the vehicle, and these are connected to the inter-vehicle distance control system 11 of the ACC-ECU by a CAN bus. Connected through.

  In the engine-ECU 15, the vehicle speed control system controls the fuel injection amount of the fuel injection control system and the ON / OFF of the exhaust brake based on the vehicle speed command from the ACC-ECU 11. The T / M-ECU 17 controls vehicle shift (clutch engagement and transmission gear shift) based on a vehicle speed command from the ACC-ECU 11. The retarder-ECU 16 controls ON / OFF of the retarder based on the vehicle speed command from the ACC-ECU 11.

FIG. 2 is a schematic diagram for explaining the configuration of the radar device 18, and means 21 for detecting position (distance, angle) information of a preceding vehicle from reception information of a radar (including a millimeter wave transmission unit and a reception unit), Means 23 for estimating the own vehicle traveling path (curvature of the center line in the traveling direction) from the vehicle speed and yaw rate of the own vehicle, and means 24 for storing the horizontal lane width (set value) to be given to the center line of the own vehicle traveling path , Means 25 for setting the lane shape of the own vehicle traveling path from the center line and the lane width of the own vehicle traveling path, and the preceding vehicle on the closest lane shape of the own vehicle traveling path based on the position information of the preceding vehicle And means 26 for outputting the position information of the preceding vehicle to the ACC unit 11 while being determined as (following control target). A vehicle speed sensor 27 detects the vehicle speed of the host vehicle.

FIG. 3 is an explanatory diagram of the lane shape, and the own vehicle traveling path (the center line in the traveling direction) is estimated from the yaw rate and the vehicle speed of the own vehicle, and the horizontal lane width on this center line (see FIG. 4). , The lane shape (shaded area) of the own vehicle traveling path is set. The left is the lane shape when traveling straight, and the right is the lane shape when turning. The lane width (set value) is uniformly set in the traveling direction in the case of a straight road. During the turning operation shown in the figure, since the center line in the traveling direction is curved, the lane width in a direction perpendicular to the tangent line (not shown) is smaller than the lane width in the horizontal direction. A lane width changing means (see S10 in FIG. 8 ) is provided in order to match the width.

  In the lane width changing means, a lane width changing map as shown in the table of FIG. 5 is set, and based on the radius of curvature (the reciprocal of the estimated curvature) and the distance of the front vehicle position information, The horizontal lane width is changed. In FIG. 5, the intermediate value of each lane width is obtained by interpolation processing. A numerical value exemplified as the lane width of the straight road corresponds to the set value of the storage means 24.

  FIG. 4 is an explanatory diagram of the preceding vehicle determination method. The preceding vehicle is determined from the lane shape and the front vehicle position information. In FIG. 4, three front vehicles are captured by the radar, The preceding car is not on the lane shape and is not a candidate for the preceding car. ● The preceding vehicle in ● is a preceding vehicle candidate because it is in the lane shape, and because there is only one preceding vehicle candidate in ●, this is determined as the preceding vehicle that the subject vehicle should follow. It is. The position information of the preceding vehicle is output to the ACC system 11, and the braking / driving force of the vehicle is controlled in the inter-vehicle distance control system so that the actual inter-vehicle distance from the preceding vehicle is maintained at the target inter-vehicle distance.

The lane width is changed by the lane width changing means (see S10 in FIG. 8 ) according to the radius of curvature of the own vehicle traveling path and the distance of the front vehicle position information. Therefore, it is possible to accurately match the preceding vehicle that the vehicle should follow.

  When the vehicle side of the front vehicle enters the millimeter wave reflection range due to the yawing of the host vehicle or the yaw of the front vehicle, the center of the reflection width of the front vehicle is displaced. Therefore, means 30 (see FIG. 2) for correcting the error is provided.

  In the correction means 30, a forward vehicle position information correction map as shown in the table of FIG. 6 is set, and the radar front vehicle angle information is determined by a gain (correction coefficient) corresponding to the radar front vehicle position information (angle and distance). Is to be corrected. Front vehicle angle information after correction = Radar front vehicle angle information × Gain. In FIG. 6, the intermediate value of each gain is obtained by interpolation processing.

In FIG. 2, 32 is a first filter that removes (smooths) noise (high frequency component) riding on the yaw rate, 33 is a second filter, and 34 calculates the fluctuation of the yaw rate after the second filter processing. Means. When the first filter 32 determines the occurrence of the yaw rate fluctuation (low frequency component) due to the steering of the vehicle based on the input from the computing means 34 (calculated value of the yaw rate fluctuation), the first filter 32 sets the time constant to that when the vehicle goes straight ahead. Means (not shown) for correcting relatively small is provided. The time constant of the second filter 33 is set to a predetermined fixed value.

  In the first filter, the time constant of the first filter 32 is corrected to be small when the fluctuation (low frequency component) accompanying the steering of the vehicle is determined from the yaw rate after the second filter processing. For this reason, the response delay of the 1st filter 32 becomes small, and a preceding vehicle can be caught appropriately also in S character curve etc. The time constant of the first filter 32 when traveling straight ahead can be set large in order to increase the removal rate of noise riding on the yaw rate.

  By setting the time constant of the second filter 33 small, it is possible to determine the fluctuation of the yaw rate with high sensitivity, and the correction (adjustment) of the time constant of the first filter 32 is accelerated. The curvature of the vehicle traveling path can be accurately estimated from the processed yaw rate and the vehicle speed detection signal. In the case of only the first filter 32, it is difficult to set a time constant when traveling straight. That is, by adding the second filter 33, the first filter 32 can determine the fluctuation of the yaw rate with high sensitivity, and can also minimize the response delay. Further, the time constant of the first filter 32 is easy to set on the basis of the time constant of the second filter 33 because it is a fixed value.

  Reference numeral 31 denotes a means for correcting a detection error (including a physical operation delay) of the yaw rate sensor 19. The detection error of the yaw rate sensor 19 has a proportional relationship with the fluctuation of the yaw rate. In this example, a yaw rate correction map as shown in the table of FIG. 7 is set, and the gain corresponding to the radius of curvature (the reciprocal of the estimated curvature). Based on (correction coefficient), the detection error of the yaw rate sensor 19 is corrected together with the response delay of the second filter 33. Yaw rate after correction = output value of yaw rate sensor × gain. In FIG. 7, the intermediate value of each gain is obtained by interpolation processing.

  Since the detection error of the yaw rate sensor 19 includes a physical operation delay (response delay), even when the vehicle is traveling straight ahead, the detection error that is mixed with noise (a high-frequency component due to engine vibration or the like) also shifts to the vehicle turning. Then, it becomes large with this. Since the error is removed by the correction means 31 together with the response delay of the second filter 33, the curvature of the own vehicle traveling path can be accurately estimated.

  FIG. 8 is a flowchart for explaining the control contents of the lator device, and is executed at predetermined intervals. In S1, a vehicle speed detection signal is read. In S2, the detection signal of the yaw rate sensor 19 is read. In S3, the radar front vehicle position information is read.

  In S4, the curvature of the center line of the own vehicle traveling path is estimated from the detection information of the vehicle speed sensor 27 and the yaw rate after the second filter processing. In S5, based on the yaw rate correction map of FIG. 7, the detection error of the yaw rate sensor is corrected together with the response delay of the second filter by the gain corresponding to the radius of curvature (the reciprocal of the estimated curvature of S4). In S6, the time constant of the first filter is adjusted (corrected) based on the calculated value of the yaw rate fluctuation.

  In S7, the curvature of the center line in the traveling direction of the host vehicle is estimated from the vehicle speed detection signal and the yaw rate after the first filter processing. In S8, the forward vehicle angle information is corrected by a gain corresponding to the forward vehicle position information (angle, distance) based on the forward vehicle position information correction map of FIG.

  In S9, the lane shape of the own vehicle traveling path is set by giving the lane width to the center line in the own vehicle traveling direction. In S10, based on the lane width change map of FIG. 5, the lane width is changed to the lane width of the lane shape according to the curvature radius of the own vehicle traveling path and the distance of the front vehicle position information. In S11, based on the lane shape and forward vehicle position information (forward vehicle distance information, corrected forward vehicle angle information), the nearest forward vehicle on the lane shape of the own vehicle traveling path should be maintained at a predetermined inter-vehicle distance. It is determined as the target preceding vehicle.

  By such control, it is possible to accurately capture the preceding vehicle that the host vehicle should follow even on an S-shaped curve or the like. Therefore, highly reliable follow-up control can be realized in the ACC system.

  The second filter 33 allows the first filter 32 to determine the yaw rate variation with high sensitivity and to minimize the response delay. Since the response delay of the second filter 33 is corrected together with the detection error of the yaw rate sensor 19, the curvature of the own vehicle traveling path can be accurately estimated even in an S-shaped curve or the like.

In the forward vehicle position information, errors caused by the yawing of the own vehicle and the yawing of the preceding vehicle are corrected without excess or deficiency, so that the lane width changing means (refer to S10 in FIG. 8 ) also in the S-curve etc. Due to the synergistic effect, the preceding vehicle can be accurately determined.

  In the above description, the embodiment has been described using the ACC system. However, the present invention is not limited to this and can be applied to an apparatus that recognizes a preceding vehicle.

It is a schematic diagram explaining the structure of an ACC system It is a block diagram explaining the structure of a radar apparatus. It is explanatory drawing of a lane shape. It is explanatory drawing of the determination method of a preceding vehicle. It is a table | surface which illustrates a lane width change map. It is a table | surface which illustrates a front vehicle position information correction map. It is a table | surface which illustrates a yaw rate correction map. It is a flowchart explaining the control content of a radar apparatus.

Explanation of symbols

10 ACC system 11 Inter-vehicle distance control system 15 Engine-ECU
17 T / M-ECU
DESCRIPTION OF SYMBOLS 18 RATE apparatus 19 Yaw rate sensor 21 Front vehicle information detection means 23 Own vehicle travel path estimation means 24 Lane width setting means 25 Lane shape setting means 26 Leading vehicle determination means 27 Vehicle speed sensor 31 Yaw rate correction means 32 First filter 33 Second filter 34 Yaw rate fluctuation calculation means 35 Own vehicle traveling path curvature estimation means

Claims (2)

A yaw rate sensor that detects the yaw rate of the vehicle;
Means for detecting the speed of the vehicle;
Curvature estimation means for estimating the curvature of the vehicle traveling path based on the detection signal of the yaw rate and the detection signal of the vehicle speed;
Means for setting the lane width of the own vehicle traveling path;
Means for setting the lane shape of the own vehicle traveling path from the estimated curvature estimated by the curvature estimating means and the lane width;
Yaw rate correction means for correcting the detection error of the yaw rate sensor;
With
The yaw rate correction means comprises means for setting a gain corresponding to the reciprocal of the estimated curvature as a parameter , and means for correcting the detected value of yaw rate = the gain × the output value of the yaw rate sensor. Is set to a larger value as the reciprocal of the estimated curvature becomes smaller . A yaw rate sensor that detects the yaw rate of the vehicle;
Means for detecting the speed of the vehicle;
A first filter for removing noise included in the detection signal of the yaw rate sensor;
First curvature estimation means for estimating the curvature of the vehicle traveling path from the yaw rate after the first filter processing and the detection signal of the vehicle speed;
Means for setting the lane width of the own vehicle traveling path;
Means for setting the lane shape of the own vehicle traveling path from the curvature estimated by the first curvature estimating means and the lane width;
A second filter for removing noise included in the yaw rate detection signal;
Means for calculating fluctuations in yaw rate after the second filter processing;
Means for adjusting the time constant of the first filter based on this variation;
Second curvature estimation means for estimating the curvature of the vehicle traveling path from the yaw rate after the second filter processing and the detection signal of the vehicle speed;
Yaw rate correction means for correcting a detection error of the yaw rate sensor based on the curvature estimated by the second curvature estimation means ,
The yaw rate correcting means corrects the gain corresponding to the inverse of the curvature estimated by the second curvature estimating means as a parameter, and the detected value of the yaw rate = the gain × the output value of the yaw rate sensor. The in-vehicle radar device according to claim 1 , wherein the gain is set to a larger value as a reciprocal of the estimated curvature becomes smaller .