JP2016200443A - Obstacle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction in detection accuracy of an obstacle due to the sticking of sensing.SOLUTION: An obstacle detection device detects an obstacle using a first radar sensor having a first sensing area expanding in the lateral direction of a vehicle and a second radar sensor having a second sensing area expanding in the lateral direction, and includes: an estimation part for estimating a relative position of the object entering into a dead angle area between the first sensing area and the second sensing area against the vehicle through the first sensing area; and a determination part for determining whether the sticking of the sensing of the first radar sensor occurs based on the detection result of the obstacle by the first radar sensor when the obstacle is included in the first sensing area. The estimation part estimates the relative position of the obstacle based on the detection result of the obstacle by the first radar sensor before the determination is made when the sticking is determined to occur by the determination part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an obstacle detection apparatus that detects an obstacle.

  JP, 2005-032063, A is known as technical literature about an obstacle detection device which detects obstacles, such as other vehicles conventionally. This publication discloses an obstacle detection device that detects an obstacle using a plurality of sensors whose sensing areas do not overlap each other, and passes between the sensing areas of one sensor and the sensing areas of other sensors. A device for estimating the position of an obstacle in the blind spot area based on the detection result of the past sensor when an obstacle enters the blind spot area is shown.

JP 2005-032063 A

  By the way, when a radar sensor is used as a sensor, detection in the vicinity of the boundary of the sensing area is unstable, so that the position information detected by the radar sensor does not change even though the actual obstacle is moving. Sometimes sticking occurs. Such sensing sticking is likely to occur when an obstruction that is long in the front-rear direction such as a truck passes through the sensing area. Sensing sticking is problematic because it reduces the accuracy of obstacle detection by the device.

  Therefore, in this technical field, it is desired to provide an obstacle detection device that can suppress a decrease in the detection accuracy of an obstacle caused by sensing fixation.

  In order to solve the above-described problem, the present invention provides a first radar sensor having a first sensing region that extends to the side of the vehicle, and a second sensing that extends to the side of the vehicle in front of the first sensing region. An obstacle detection device that detects an obstacle using a second radar sensor having a region, and based on a detection result of the obstacle by the first radar sensor, the first radar passes through the first sensing region. An estimation unit that estimates the relative position of the obstacle that has entered the blind spot area between the sensing area and the second sensing area with respect to the vehicle, and the first radar sensor when the obstacle is included in the first sensing area. And a determination unit that determines whether or not the sensing fixation of the first radar sensor has occurred based on the detection result of the obstacle by the vehicle, and the determination unit The relative speed of the obstacle is greater than or equal to the first threshold, and the relative position of the obstacle after the predetermined time predicted based on the relative position and the relative speed of the obstacle to the vehicle and the first time after the predetermined time has elapsed. When the distance in the front-rear direction with respect to the relative position of the obstacle detected by the radar sensor is equal to or greater than the second threshold, it is determined that the sticking has occurred, and the estimation unit determines that the sticking has occurred by the determination unit An obstacle detection device that, when determined, estimates the relative position of an obstacle based on an obstacle detection result by the first radar sensor before the determination.

  According to the obstacle detection device of the present invention, it is possible to suppress a decrease in obstacle detection accuracy caused by sensing fixation.

It is a block diagram which shows the obstruction detection apparatus which concerns on this embodiment. It is a top view for demonstrating switching with sensing mode and estimation mode. It is a flowchart which shows the estimation mode switching method of the obstacle detection apparatus which concerns on this embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  An obstacle detection apparatus 1 according to the present embodiment shown in FIG. 1 is mounted on a vehicle such as a passenger car, for example, and detects an obstacle present on the side (left side or right side) of the vehicle. The obstacle is, for example, another vehicle (including a four-wheeled vehicle and a two-wheeled vehicle). Obstacles may include pedestrians, and may include structures such as utility poles and trees.

[Configuration of obstacle detection device]
As shown in FIG. 1, the obstacle detection apparatus 1 includes an ECU [Electronic Control Unit] 2 that controls the apparatus in an integrated manner. The ECU 2 is an electronic control unit having a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. The ECU 2 is connected to the first radar sensor 3, the second radar sensor 4, the vehicle speed sensor 5, the acceleration sensor 6, and the yaw rate sensor 7.

  The first radar sensor 3 is, for example, a sensor that is provided on the rear side of the left side surface of the vehicle and detects an obstacle on the left side of the vehicle. The first radar sensor 3 has a first sensing area A that extends to the left side of the vehicle. The first radar sensor 3 is, for example, a millimeter wave radar sensor that uses a millimeter wave, and detects the obstacle by transmitting the millimeter wave and receiving the millimeter wave reflected by the obstacle. The first radar sensor 3 detects the relative position and the relative speed of the obstacle with respect to the vehicle, for example, by FM-CW [Frequency Modulated-Continuous Wave] method. The first radar sensor 3 transmits obstacle information including the relative position and relative speed of the obstacle to the ECU 2.

  The second radar sensor 4 is, for example, a sensor that is provided on the front side of the left side surface of the vehicle and detects an obstacle on the left side of the vehicle. The second radar sensor 4 has a second sensing area B that extends to the left side of the vehicle. The second sensing area B is located on the front side of the vehicle with respect to the first sensing area A.

  The second radar sensor 4 is also a millimeter wave radar sensor that uses millimeter waves, for example. The second radar sensor 4 detects the relative position and relative speed of the obstacle with respect to the vehicle, for example, by the FM-CW method. The second radar sensor 4 transmits obstacle information including the relative position and velocity of the obstacle to the ECU 2. The first radar sensor 3 and the second radar sensor 4 may use LIDAR [Laser Imaging Detection and Ranging] or the like instead of the millimeter wave radar sensor.

  The vehicle speed sensor 5 is a detector that detects the speed of the vehicle. As the vehicle speed sensor 5, for example, a wheel speed sensor that is provided on a vehicle wheel or a drive shaft that rotates integrally with the wheel and detects the rotation speed of the wheel is used. The vehicle speed sensor 5 transmits the detected vehicle speed information to the ECU 2.

  The acceleration sensor 6 is a detector that detects the acceleration of the vehicle. The acceleration sensor 6 includes, for example, a longitudinal acceleration sensor that detects acceleration in the longitudinal direction of the vehicle and a lateral acceleration sensor that detects lateral acceleration of the vehicle. For example, the acceleration sensor 6 transmits the detected acceleration information to the ECU 2.

  The yaw rate sensor 7 is a detector that detects the yaw rate (rotational angular velocity) around the vertical axis of the center of gravity of the vehicle. As the yaw rate sensor 7, for example, a gyro sensor can be used. The yaw rate sensor transmits the detected yaw rate information of the vehicle to the ECU 2.

  The driving support unit 8 is a device that performs driving support for the driver of the vehicle. For example, the driving support unit 8 performs driving support using the detection result of the obstacle detected by the obstacle detection device 1. The driving assistance includes, for example, collision avoidance assistance that avoids collision between the vehicle and an obstacle, and lane change assistance that assists the driver in changing the lane of the vehicle. Note that the device that uses the obstacle detection result is not limited to driving support.

  Next, the functional configuration of the ECU 2 will be described. The ECU 2 includes an estimation unit 10 and a determination unit 11.

  The estimation unit 10 executes the sensing mode or the estimation mode. The sensing mode is a mode in which obstacle information detected by the first radar sensor 3 or the second radar sensor 4 is output to the driving support unit 8. In the estimation mode, the relative position of the current obstacle is estimated based on the past obstacle information detected by the first radar sensor 3 or the second radar sensor 4, and the estimated obstacle information is output to the outside. Mode. In the estimation mode, for example, the relative speed is treated as not changing from the last detected value.

  The determination unit 11 switches between the sensing mode and the estimation mode of the estimation unit 10 based on the detection result of the first radar sensor 3. For example, the determination unit 11 switches the sensing mode and the estimation mode of the estimation unit 10 by transmitting a switching signal to the estimation unit 10. For example, the determination unit 11 can switch between the sensing mode and the estimation mode for each part of the obstacle (for example, for each reflection point that reflects the millimeter wave).

  Hereinafter, switching between the sensing mode and the estimation mode will be described with reference to FIG. FIG. 2 is a plan view for explaining switching between the sensing mode and the estimation mode. 2 shows a vehicle M, a traveling lane R1 on which the vehicle M travels, an adjacent lane R2 adjacent to the traveling lane R1, a first sensing area A in the first radar sensor 3, and a second in the second radar sensor 4. Sensing area B, other vehicle (obstacle) N traveling in adjacent lane R2, future position Nf of other vehicle N, reflection point P in other vehicle N, and reflection point Pf which is reflection point P in future position Nf Show.

  An arrow D1 shown in FIG. 2 indicates transmission / reception of millimeter waves of the first radar sensor 3 with respect to the reflection point P. Similarly, the arrow D2 indicates transmission / reception of millimeter waves of the second radar sensor 4 with respect to the reflection point Pf. Further, FIG. 2 shows an XY coordinate system. The X-axis direction is the vehicle width direction of the vehicle M. The Y-axis direction is the front-rear direction of the vehicle M.

  As shown in FIG. 2, a blind spot area C exists between the first sensing area A and the second sensing area B. The blind spot area C is an area in which an obstacle cannot be detected by the first radar sensor 3 or the second radar sensor 4. Note that the first sensing area A and the second sensing area B are areas that do not overlap each other, but may partially overlap. The present invention can be applied when the blind spot region C exists between the first sensing region A and the second sensing region B.

  In the situation shown in FIG. 2, the estimation unit 10 first detects the other vehicle N included in the first sensing area A by the first radar sensor 3 in the sensing mode. The other vehicle N is, for example, a truck having a certain length in the front-rear direction. For example, the estimating unit 10 reflects the millimeter wave transmitted by the first radar sensor 3 at the reflection point P located on the side surface of the other vehicle N on the vehicle M side, and the first radar sensor 3 receives the millimeter wave again. The relative speed and the relative position of the reflection point P of the other vehicle N with respect to the vehicle M are detected. The estimation unit 10 detects the other vehicle N as a continuum of reflection points P, for example.

  Here, it is assumed that the other vehicle N is another vehicle having a speed higher than that of the vehicle M. That is, the relative speed of the other vehicle N with respect to the vehicle M in the front-rear direction (Y-axis direction) is a positive value. On the other hand, when the vehicle speed of the other vehicle N is smaller than that of the vehicle M, the relative speed of the other vehicle N with respect to the vehicle M in the front-rear direction is a negative value. The other vehicle N having a higher speed than the vehicle M passes through the first sensing area A and enters the blind spot area C, and then enters the second sensing area B.

  When the first radar sensor 3 has lost the reflection point P of the other vehicle N due to the forward movement of the other vehicle N (when no longer detected), the determination unit 11 estimates the estimation unit 10 from the sensing mode for the reflection point P. Switch to mode. The estimation unit 10 estimates the relative position of the reflection point P in the blind spot area C based on, for example, the last detected relative velocity and relative position of the reflection point P. For example, the estimation unit 10 assumes that the relative velocity of the last detected reflection point P is maintained, and uses the relative position of the last detected reflection point P as a reference in accordance with the elapsed time since the loss. The relative position of the reflection point P is estimated. In addition, the estimation unit 10 may estimate the relative position of the reflection point P in the blind spot area C by a known method.

  When the other vehicle N further moves forward and the second radar sensor 4 detects the reflection point Pf in the second sensing region B, the estimation unit 10 reflects the reflection based on the estimation result of the relative position of the reflection point P. It is determined whether or not the point Pf is the same as the reflection point P. For example, when the distance between the estimated relative position of the reflection point P and the relative position of the reflection point Pf in the Y-axis direction is within a preset error region, the estimation unit 10 has the same reflection point Pf as the reflection point P. Judge that there is. As described above, in the obstacle detection apparatus 1, the reflection point Pf detected in the second sensing region B is the same as the reflection point P when the estimation unit 10 estimates the relative position of the reflection point P in the blind spot region C. Therefore, it is possible to continuously detect the reflection points P including the blind spot area C.

  Here, sensing fixation will be described. In the detection by the radar sensor, the reflection point P is in the relative position of the reflection point P detected by the radar sensor even though the reflection point P actually moves with respect to the vehicle M because of unstable detection near the boundary of the sensing area. There are times when sensing sticking that does not change occurs. For example, when the other vehicle N is a truck having a flat side surface, the radar sensor detects a change in the relative position because the same reflection occurs at the same position as the previous reflection point P even if the other vehicle N moves forward a little. There are things that cannot be done.

  When such sensing sticking occurs, the conventional obstacle detection device cannot recognize that the reflection point P has already been lost due to the forward movement of the other vehicle N, and for example, reflects until the entire other vehicle N is lost. It was recognized that the point P remained in the first sensing area A. Thereafter, in the conventional obstacle detection device, when the other vehicle N moves forward and passes through the first sensing area A and enters the second sensing area B, the actual reflection point P (reflection point Pf) is the second. It is detected by the radar sensor 4. In this case, in the conventional obstacle detection device, the reflection point P, which has been recognized as staying in the first sensing area A until immediately before, is detected as if it has moved to the second sensing area B in an instant, and the reflection is detected. Discontinuity of the position information (relative position information) of the point P occurred.

  On the other hand, in the obstacle detection device 1 according to the present embodiment, the determination unit 11 determines whether sensing sticking has occurred. The determination unit 11 determines whether sensing sticking has occurred based on the detection result of the first radar sensor 3.

  Specifically, the determination unit 11 determines whether the relative speed of the reflection point P in the front-rear direction is equal to or higher than the first threshold based on the detection result of the first radar sensor 3. The first threshold value is a value (positive value) appropriately set for determining sensing sticking. The case where the relative speed of the reflection point P in the front-rear direction is equal to or higher than the first threshold corresponds to the case where the speed of the other vehicle N is higher than the speed of the vehicle M than the first threshold. The determination unit 11 calculates the relative speed in the front-rear direction (front-rear direction component of the relative speed) by recognizing the front-rear direction using the yaw rate information of the yaw rate sensor 7, for example.

  If the determination unit 11 determines that the relative speed of the reflection point P in the front-rear direction is greater than or equal to the first threshold, the determination unit 11 predicts the relative position of the reflection point P after a predetermined time ΔT has elapsed. The predetermined time ΔT is a time appropriately set for determination of sensing sticking. The determination unit 11 predicts the relative position of the reflection point P after a predetermined time ΔT has elapsed, assuming that the relative speed of the reflection point P is maintained. The determination unit 11 may change the predetermined time ΔT so that the predicted relative position of the reflection point P is within the first sensing region A.

  The determination unit 11 recognizes the relative position of the reflection point P detected by the first radar sensor 3 after a predetermined time ΔT has elapsed. The determination unit 11 determines whether or not the distance between the predicted relative position of the reflection point P and the detected relative position of the reflection point P in the front-rear direction is equal to or greater than a second threshold value. The second threshold value is a value appropriately set for determination of sensing sticking. For example, the determination unit 11 recognizes the front-rear direction using the yaw rate information of the yaw rate sensor 7. If the determination unit 11 determines that the distance between the predicted relative position of the reflection point P and the detected relative position of the reflection point P in the front-rear direction is equal to or greater than the second threshold value, the relative speed is sufficiently large. Since the relative position hardly changes, it is determined that the sensing is stuck.

  If the determination unit 11 determines that sensing sticking has occurred, the determination unit 11 switches the estimation unit 10 from the sensing mode to the estimation mode for the reflection point P. In this case, the estimation unit 10 estimates the relative position of the reflection point P even if the reflection point P is included in the first sensing region A. The estimation unit 10 determines the reflection point P based on the detection result (relative position and relative speed of the reflection point P) of the first radar sensor 3 before the determination unit 11 determines that sensing sticking has occurred. The relative position of is estimated.

  The estimation unit 10 assumes, for example, that the relative speed of the reflection point P detected immediately before the determination is maintained, and determines from the determination based on the relative position of the reflection point P detected immediately before the determination by the determination unit 11. The relative position of the reflection point P according to the elapsed time is estimated. In addition, the estimation unit 10 may estimate the relative position of the reflection point P by a known method. The estimation unit 10 may further improve the accuracy of estimating the relative position of the reflection point P by adopting a known method using the vehicle speed information of the vehicle speed sensor 5 and the acceleration information of the acceleration sensor 6.

  In addition, when the determination unit 11 detects the reflection point Pf in the second sensing region B as the other vehicle N moves forward, the determination unit 11 does not immediately start the sensing mode for the reflection point Pf, but the reflection point Pf is the second point. The sensing mode may be started after proceeding to the inside of the second sensing area B beyond the vicinity of the boundary of the sensing area B. Thereby, it is possible to avoid the instability of recognition near the boundary of the second sensing region B from affecting the detection result. An appropriate area is set in advance as the vicinity of the boundary. If the determination unit 11 determines that the reflection point P and the reflection point Pf are the same based on the estimation result of the relative position of the reflection point P in the blind spot area C, the determination unit 11 ends the reflection point P estimation mode. Switch to sensing mode.

[How to switch the estimation mode of the obstacle detection device]
Next, the estimation mode switching method of the obstacle detection apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the estimation mode switching method of the obstacle detection apparatus 1 according to the present embodiment. The flowchart shown in FIG. 3 is repeatedly executed while the vehicle M is traveling, for example.

  As shown in FIG. 3, the ECU 2 of the obstacle detection apparatus 1 determines whether or not an obstacle (or a part of the obstacle such as the reflection point P) exists in the first sensing area A as step S101. judge. When the ECU 2 determines that there is no obstacle in the first sensing area A (S101: NO), the ECU 2 ends the current process. Then, ECU2 performs step S101 again after progress of the preset time. On the other hand, when the ECU 2 determines that there is an obstacle in the first sensing area A (S101: YES), the ECU 2 proceeds to step S102.

  In step S102, the ECU 2 determines whether the relative speed between the vehicle M and the obstacle in the front-rear direction (Y-axis direction) of the vehicle M is greater than or equal to the first threshold value by the determination unit 11. When it is determined that the relative speed between the vehicle M and the obstacle in the front-rear direction is not equal to or higher than the first threshold (S102: NO), the ECU 2 ends the current process because it cannot determine the sensing sticking. Then, ECU2 performs step S101 again after progress of the preset time. On the other hand, when the determination unit 11 determines that the relative speed between the vehicle M and the obstacle in the front-rear direction is equal to or higher than the first threshold (S102: YES), the ECU 2 proceeds to step S103.

  In step S103, the ECU 2 predicts the relative position of the obstacle after the predetermined time ΔT has elapsed by the determination unit 11. The determination unit 11 predicts the relative position of the obstacle after a predetermined time ΔT, assuming that the current relative speed of the obstacle is maintained, for example. The ECU 2 waits for the elapse of the predetermined time ΔT, and detects the relative position of the obstacle after the elapse of the predetermined time ΔT by the first radar sensor 3. Thereafter, the ECU 2 proceeds to step S104.

  In step S104, the ECU 2 causes the determination unit 11 to determine whether the distance in the front-rear direction between the predicted relative position of the obstacle and the detected relative position after the lapse of the predetermined time ΔT is equal to or greater than a second threshold value. . If it is determined that the distance is not greater than or equal to the second threshold (S104: NO), the ECU 2 terminates the current process because it cannot be said that sensing sticking has occurred. Then, ECU2 performs step S101 again after progress of the preset time. On the other hand, when it is determined that the distance is equal to or greater than the second threshold (S104: YES), the ECU 2 proceeds to step S105.

  In step S <b> 105, the ECU 2 determines that sensing sticking has occurred by the determination unit 11. Thereafter, the ECU 2 proceeds to step S106.

  In step S106, the ECU 2 causes the determination unit 11 to change the estimation unit 10 from the sensing mode to the estimation mode for an obstacle (or a part of an obstacle such as the reflection point P) that has been determined to have sensing sticking. Switch. Thereafter, the ECU 2 ends the current process.

[Effects of obstacle detection device]
According to the obstacle detection device 1 according to the present embodiment, when it is determined that the sensing sticking occurs, the relative position of the obstacle is estimated even if the obstacle is not lost. It is possible to avoid outputting the information of the incorrect relative position as it is, and it is possible to suppress a decrease in obstacle detection accuracy. According to this obstacle detection device 1, it is possible to avoid the output of discontinuous position information such as a jump from the first sensing area A to the second sensing area B for the obstacle, Continuous positioning information can be output even for obstacles that are long in the direction.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above. The present invention can be implemented in various forms including various modifications and improvements based on the knowledge of those skilled in the art including the above-described embodiments.

  For example, in the above-described embodiment, the first radar sensor 3 and the second radar sensor 4 provided on the left side of the vehicle have been described as examples. However, the first radar sensor 3 and the second radar sensor 4 are It may be provided on the right side of the vehicle.

  DESCRIPTION OF SYMBOLS 1 ... Obstacle detection apparatus, 2 ... ECU, 3 ... 1st radar sensor, 4 ... 2nd radar sensor, 5 ... Vehicle speed sensor, 6 ... Acceleration sensor, 7 ... Yaw rate sensor, 8 ... Driving support part, 10 ... Estimating unit, 11 ... determining unit, A ... first sensing region, B ... second sensing region, C ... dead angle region, M ... vehicle, N ... other vehicle, Nf ... future position, P ... reflection point, Pf ... future reflection point, R1 ... running lane, R2 ... adjacent lane.

Claims (1)

A first radar sensor having a first sensing area extending laterally of the vehicle, and a second radar sensor having a second sensing area extending laterally on the front side of the vehicle relative to the first sensing area An obstacle detection device that detects an obstacle using
Based on the detection result of the obstacle by the first radar sensor, the obstacle that has entered the blind spot area between the first sensing area and the second sensing area via the first sensing area. An estimation unit for estimating a relative position with respect to the vehicle;
When the obstacle is included in the first sensing area, it is determined whether sensing of the first radar sensor is stuck based on a detection result of the obstacle by the first radar sensor. A determination unit for determining;
With
The determination unit is a case where a relative speed of the obstacle with respect to the vehicle in the front-rear direction of the vehicle is equal to or higher than a first threshold, and is predicted based on a relative position of the obstacle with respect to the vehicle and the relative speed. The distance in the front-rear direction between the relative position of the obstacle after the lapse of the predetermined time and the relative position of the obstacle detected by the first radar sensor after the lapse of the predetermined time is greater than or equal to a second threshold value. When it is determined that the sticking has occurred,
When it is determined by the determination unit that the sticking has occurred, the estimation unit determines the relative position of the obstacle based on the detection result of the obstacle by the first radar sensor before the determination. Obstacle detection device.

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