JP2015207171A - Driving assist device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving assist device capable of appropriately determining backing of a vehicle.SOLUTION: The driving assist device for performing a driving assist for a vehicle comprises: object detection means (e.g., a millimeter wave radar device, a camera device) for detecting an object existing around the vehicle; and a backing determination section for determining that the vehicle is backing, when it is determined that the vehicle gradually separates from the object being located and still in front of the vehicle (hereinafter referred to as "a still object") on the basis of location information on the still object detected by the object detection means.

Description

  The present disclosure relates to a driving support device.

  In recent years, based on information obtained from a radar device or the like mounted on the host vehicle, the possibility of a collision with an obstacle such as another vehicle located in front of the host vehicle is predicted, and braking or An apparatus for reducing the impact at the time of collision by winding a belt or the like has been put into practical use.

  Such control is sometimes referred to as pre-crash safety control, and is hereinafter simply referred to as PCS (Pre-Crash Safety System) control.

  By the way, this PCS control may not be able to cope with the behavior of the host vehicle accompanying the braking by the PCS control depending on the traveling speed of the host vehicle, the road surface condition, and the like.

  On the other hand, a technique for performing reverse determination of the host vehicle is known (see, for example, Patent Document 1). In patent document 1, the reverse determination of the own vehicle is performed based on the vehicle speed detected by the vehicle speed sensor and the selected position of the shift lever.

JP 2013-002619 A

  However, as in Patent Document 1, when the reverse determination of the host vehicle is performed based on the selected position of the shift lever, there is a risk that an erroneous determination of the reverse determination may be performed depending on the inclination angle of the road surface. For example, when the shift lever is selected to the reverse (R) position, the host vehicle may move forward if the downward inclination angle is steep. In this case, it is erroneously determined that the host vehicle is moving backward although the host vehicle is moving forward, and the PCS control is not activated.

  On the other hand, when the shift lever is selected at the drive (D) position, the host vehicle may move backward if the upward inclination angle is steep. In this case, since it is erroneously determined that the host vehicle is moving backward but not moving backward (moving forward), the PCS control is activated.

  If the PCS control is activated when the host vehicle is moving backward, the driver cannot cope with the behavior of the host vehicle accompanying the braking by the PCS control, and the behavior often becomes unstable.

  As described above, according to the above-described Patent Document 1, there is a case where the reverse determination is erroneously determined. Therefore, the PCS control may be activated when it is not necessary to activate the PCS control.

  In view of the above, an object of the present disclosure is to provide a driving support device capable of appropriately performing the reverse determination of the vehicle.

  According to one aspect of the present disclosure, in a driving support device that supports driving of a vehicle, an object detection unit that detects an object around the vehicle, and a stationary position that is located in front of the vehicle that is detected by the object detection unit. And a reverse determination unit that determines that the vehicle is moving backward when it is determined that the vehicle is gradually moving away from the stationary object based on position information of a moving object. Is obtained.

  According to the present disclosure, it is possible to obtain a driving assistance device that can appropriately determine whether the vehicle is going backward.

It is a block diagram which shows an example of the whole structure of the driving assistance device which concerns on one Embodiment. 2 is a flowchart illustrating an example of a control process of the driving support device illustrated in FIG. 1.

(Configuration of the driving support device 1)
Hereinafter, the driving support apparatus according to the present embodiment will be described with reference to the accompanying drawings.

  The driving support device is a device that detects an object (an obstacle around the host vehicle, a preceding vehicle, a pedestrian, etc.) and prevents or reduces a collision with the detected object. FIG. 1 is a block diagram illustrating an example of the overall configuration of a driving support apparatus according to an embodiment.

  The driving support device 1 is a device for supporting driving of the host vehicle and is mounted on the host vehicle. The driving support device 1 includes an object detection unit 10 and a PCS-ECU (Electronic Control Unit) 20 as main components.

  The object detection means 10 is, for example, a millimeter wave radar device 11 and is disposed at a front portion near the front grill or the front bumper of the host vehicle. The object detection means 10 irradiates a transmission wave to an irradiation range including a front object (an obstacle, a preceding vehicle, a pedestrian, etc.) located in front of the host vehicle by the FM-CW method, for example, and reflects the reflected wave. By detecting, a scanned image including an obstacle is recognized. Thereby, a relative distance, a relative speed, and a lateral displacement (or direction) with respect to an object located in front of the host vehicle are calculated, and these calculation results are transmitted to the PCS-ECU 20.

  Here, the “lateral displacement” means a deviation from the extension line of the central axis of the host vehicle, and is calculated by an internal circuit of the millimeter wave radar device 11 based on the distance and the direction. Instead of the millimeter wave radar device 11, a laser radar, a sonar, a camera device, or the like may be provided. The camera device 12 is, for example, a stereo camera device or a moving stereo camera device.

  When the camera device 12 is used, the distance and the lateral position of the object are obtained by mapping the position on the captured image to the position on the actual road plane. The relative speed can be obtained by differentiating the distance. In this embodiment, as shown in FIG. 1, the case where both the millimeter wave radar device 11 and the camera device 12 are provided is illustrated. Thus, a plurality of means for detecting an object may be provided.

  The PCS-ECU 20 is, for example, a computer unit in which a ROM 22, a RAM 23, and a reverse determination unit 24 are connected to each other via a bus with a CPU 21 as a center. In addition, the PCS-ECU 20 includes a storage device such as an HDD (Hard Disc Drive), a DVD (Digital Versatile Disk) drive, a CD-ROM drive, and a flash memory, an I / O port, a timer, a counter, and the like. The ROM 22 stores programs and data executed by the CPU 21. In addition, the PCS-ECU 20 performs reverse determination on the host vehicle based on the reverse determination unit 24, receives a result of the determination, and the CPU 21 executes a program stored in the ROM 22 as a main functional block that functions as a main functional block. In this case, the PCS control is activated.

  A steering angle sensor 13 that detects the steering angle of the wheel shaft is connected to the PCS-ECU 20 of the driving support device 1. The PCS-ECU 20 can recognize the steering direction of the host vehicle based on the steering angle detected by the steering angle sensor 13. There are various detection principles for the steering angle sensor 13. For example, S pole and N pole magnetic bodies are arranged on the wheel shaft side, and the periphery of the wheel shaft is surrounded in a ring shape. The rotation angle is detected by detecting a change in magnetism.

  The yaw rate sensor 14 is connected to the PCS-ECU 20. The yaw rate sensor 14 detects the yaw rate around the longitudinal axis of the host vehicle and outputs the detection result to the PCS-ECU 20. The PCS-ECU 20 obtains a turning radius from the yaw rate, determines whether or not to deviate from the lane, and appropriately gives a warning using a buzzer or a warning light (not shown).

  Further, a shift position sensor 15 is connected to the PCS-ECU 20 to detect and shift a selected position (forward D 1 · 2, neutral N, reverse R, parking P, etc.). The position signal is output to the PCS-ECU 20.

  A PCS switch (or PCS control switch) 16 is connected to the PCS-ECU 20. The PCS switch 16 is for the driver to perform various operations for PCS control. The driver can turn on / off the PCS control, input a detection target distance, set a safety level, and the like by the PCS switch 16.

  The driver can turn off the PCS control by pressing the PCS switch 16. In this case, a PCS control off signal is transmitted from the PCS switch 16 to the PCS-ECU 20. The PCS-ECU 20 performs control so that PCS control is not performed based on the off signal transmitted from the PCS switch 16. The PCS switch 16 is provided on the back side of the handle, for example. When the PCS switch 16 is not pressed, the PCS control is in an on state, and when the driver presses the PCS switch 16, the PCS control is in an off state.

  Further, a meter ECU 30 and a brake ECU 40 are connected to the PCS-ECU 20.

  The meter ECU 30 includes, for example, a CPU, ROM, RAM, a data bus connecting them, and an input / output interface. The meter ECU 30 performs predetermined processing according to a program stored in the ROM, and controls a speedometer and an odometer in the instrument panel based on the vehicle speed V acquired from the PCS-ECU 20, and from the PCS-ECU 20 Based on this alarm command, control is performed to turn on a warning lamp (not shown). More specifically, the meter ECU 30 displays warnings on the meter panel, such as vehicle status such as speed and engine speed, half-doors, etc., based on various sensor signals, switch signals, and requests from the PCS-ECU 20. Or turn on a predetermined lamp to inform the driver.

  In the present embodiment, a PCS indicator 31 is connected to the meter ECU 30. The PCS indicator 31 is provided, for example, in the instrument panel, and alerts the driver visually by displaying an alarm according to an operation command from the PCS-ECU 20. Note that alerting the driver is not limited to the alarm display, and a buzzer warning device may be provided in the vehicle cabin so that a buzzer sounds according to an operation command from the PCS-ECU 20. Or you may comprise so that a warning lamp may be lighted.

  The brake ECU 40 controls the brake actuator 41 provided corresponding to the front, rear, left, and right wheels in the host vehicle, and performs brake control of the host vehicle. The brake ECU 40 includes, for example, a CPU, a ROM, a RAM, a data bus connecting them, and an input / output interface, and the CPU performs predetermined processing according to a program stored in the ROM. The brake ECU 40 controls the brake actuator 41 based on the braking command from the PCS-ECU 20 to brake the host vehicle. The brake ECU 40 controls the brake actuator 41 based on a braking command from the PCS-ECU 20 or a brake pedal operation by the driver, for example, and brakes the host vehicle. The speed V is detected, and the detection result of the vehicle speed V is output to the PCS-ECU 20. The brake actuator 41 is provided on each wheel of the host vehicle.

  Specifically, the brake ECU 40 applies the target braking force of the host vehicle based on the opening degree of the brake pedal operated by the driver, the vehicle speed, or the like, or based on a control command supplied from the PCS-ECU 20. The drive amount of the brake actuator 41 (hydraulic mechanism or electric motor) necessary for this is calculated. Then, the brake ECU 40 issues a drive command to the brake actuator 41 so that the drive amount is realized.

  The brake ECU 40 controls the brake actuator 41 to independently control the wheel cylinder pressure of each wheel without depending on the driver's operation of the brake pedal. The reverse determination unit 24 of the PCS-ECU 20 determines the reverse of the host vehicle based on the relative distance to the object, the relative speed, and the lateral displacement. If it is determined that the host vehicle is moving backward, the PCS control is performed. The PCS-ECU 20 is controlled so as not to break.

The stop lamp 42 is turned on based on a current command supplied from the brake ECU 40 when the brake ECU 40 performs braking of the host vehicle and when the brake ECU 40 performs light braking.
(Operation of the driving support device 1)
Next, operation | movement of the driving assistance device 1 which concerns on this embodiment is demonstrated, referring FIG.

  First, in the case where the driver is driving by driving the host vehicle, the driving state amount during driving is detected. Specifically, the driving state amount of the host vehicle is detected using the steering angle sensor 13, the yaw rate sensor 14, and the shift position sensor 15 connected to the driving support device 1. Detection signals based on these detection results are input to the PCS-ECU 20. The amount of driving state of the host vehicle depends on the steering angle of the wheel shaft by the steering angle sensor 13, the yaw rate of the host vehicle (change speed of the rotation angle in the turning direction) by the yaw rate sensor 14, and the shift lever selection position by the shift position sensor 15. Based on the overall judgment.

  Data from the millimeter wave radar device 11 and a captured image analysis result from the camera device 12 are output to the PCS-ECU 20. Based on these output results, the PCS-ECU 20 recognizes the relative distance, relative speed, and lateral displacement with respect to an object located in front of the host vehicle. Specifically, of the data output from the millimeter wave radar device 11, data whose existence has been confirmed by the camera device 12 is defined as an object. The PCS-ECU 20 extracts feature points having a larger luminance difference (pixel value difference including color in the case of a color image) in the captured image of the camera device 12 than adjacent pixels, and extracts them by connecting the feature points. The image area to be recognized is recognized as the contour of the object. In addition, the relative speed can be calculated by observing the time change of the distance. Therefore, the object can be recognized with sufficient accuracy by the combination of the data output from the millimeter wave radar device 11 and the captured image analysis result of the camera device 12. These data and the captured image analysis result (position information) are always output as data to the PCS-ECU 20.

  When it is determined that the host vehicle is moving backward based on the driving state quantity of the host vehicle and the position information of the object, the PCS-ECU 20 is controlled so that the PCS control is not performed.

On the other hand, if it is not determined that the host vehicle is moving backward, the PCS-ECU 20 is controlled so that the PCS control is performed. When the relative distance, relative speed, and the like with the object located in front of the host vehicle satisfy the predetermined conditions, the PCS-ECU 20 requests the brake ECU 40 to brake the host vehicle and brakes the host vehicle. In addition, when the possibility of a collision with an object becomes high, it may be configured to display an alarm according to an operation command from the PCS-ECU 20, sound an alarm sound, or turn on a warning light. Good.
(Control processing of driving support device 1)
Next, a control process of the driving support device 1 according to the present embodiment will be described. FIG. 2 is a flowchart illustrating an example of a control process of the driving support apparatus illustrated in FIG.

  First, it is determined whether or not the host vehicle is stopped (step S1). For example, based on a detection value of a wheel speed sensor (not shown), the vehicle is determined to be stopped when the detection value of the wheel speed sensor is a predetermined value or less. In combination with the selected position of the shift lever detected by the shift position sensor 15, it may be determined whether or not the host vehicle is stopped. Alternatively, the accelerator pedal and the brake pedal are each provided with an on / off switch that is turned on when the driver steps on the pedal (when the driver operates the pedal), and this is detected by turning the switch on or off. May be performed. If the host vehicle stop condition is not satisfied (NO in step S1), the process returns to step S1 again to perform a circulating loop process until the host vehicle stop condition is satisfied. Only when the own vehicle stop condition is satisfied (YES in step S1), the process proceeds to the next step S2.

  In step S2, when the host vehicle is stopped, the environment around the host vehicle is recognized from the millimeter wave radar device 11 and the camera device 12, so that a stationary object located in front of the host vehicle (hereinafter referred to as "stationary object"). The PCS-ECU 20 recognizes a stationary object. When it is determined that the stationary object recognized in the above is moving, a new stationary object is extracted as a moving object. Whether or not the stationary object has moved is determined based on the relative distance (relative position) of the stationary object to the host vehicle, the relative speed, and the like.

  The recognition of the stationary object by the PCS-ECU 20 is continuously performed until the host vehicle departs (step S3). The departure of the host vehicle is, for example, that the host vehicle departs when the detection value of the wheel speed sensor exceeds a predetermined value based on the detection value of the wheel speed sensor and the detection value increases. Is determined. Similar to the determination of the stop of the host vehicle, the departure of the host vehicle may be determined by providing the shift position sensor 15 and the on / off switch.

  If it is determined that the host vehicle has started, the process proceeds to the next step S4 to determine whether the host vehicle is moving backward. Specifically, it is determined whether or not the host vehicle is gradually away from the stationary object recognized in step S2. This determination is made based on the driving state quantity of the host vehicle based on the steering angle sensor 13, the yaw rate sensor 14, and the shift position sensor 15, and the output result of the stationary object based on the millimeter wave radar device 11 and the camera device 12. That is, when the host vehicle departs, if the host vehicle is gradually away from the stationary object recognized in step S2 (YES in step S4), that is, the relative distance (relative position) between the host vehicle and the stationary object. If the lateral displacement or the like becomes large, it is determined that the host vehicle is moving backward (step S5).

  On the other hand, when the vehicle departs, if the own vehicle gradually approaches this stationary object (NO in step S4), that is, the relative distance (relative position) between the own vehicle and the stationary object, lateral displacement, etc. When it becomes smaller, it is determined that the host vehicle is not moving backward (moving forward) (step S6).

  As described above, the backward determination of the host vehicle is performed by calculating the relative distance, the relative speed, and the like between the host vehicle and the stationary object based on the stationary object recognized by the driving support device 1. This stationary object can be recognized more accurately when the vehicle is stopped than when the host vehicle is traveling. Usually, when the host vehicle moves backward, the vehicle always stops once. Therefore, in this embodiment, the reverse determination is surely performed by recognizing a stationary object every time the vehicle stops.

  In the present embodiment, since the control is performed as described above, it is possible to prevent braking by the PCS control when the host vehicle is moving backward, and to avoid the behavior of the host vehicle becoming unstable when moving backward. it can. Therefore, it is possible to reduce the possibility that the driver cannot cope with the reverse braking and the own vehicle collides with the object. Standards related to functional safety are set for automobiles, and by performing the above-described reverse determination, it is possible to provide a vehicle suitable for functional safety. More specifically, the reduction of the possibility of collision of an object is ranked as an ASIL-A hazard. In the present embodiment, this hazard can be avoided by performing the reverse determination of the host vehicle and not performing the PCS control by the driving support device 1 while the host vehicle is moving backward.

  Here, ASIL (Automotive Safety Integrity Level) is an index related to the functional safety of the host vehicle. Specifically, ASIL is standardized to IEC61508 / ISO26262 and the like, and ISO26262 is an index for designating safety requirements and safety measures for automobiles. ASIL has five safety levels, and D, C, B, A, and QM in descending order of safety standards. The ASIL considers the magnitude of damage caused by a hazard (failure), the frequency of occurrence of the hazard, and the control difficulty level when the hazard occurs, and is determined by the vehicle manufacturer or the like.

  According to this embodiment, since the backward determination of the host vehicle is performed by existing sensors such as the millimeter wave radar device 11 and the camera device 12, the driving support device 1 can be reduced in price. In addition, since the existing sensor respond | corresponds to the hazard of ASIL-B, it can perform reverse determination of the own vehicle with high reliability.

  As a method for determining the reverse of the host vehicle, a wheel speed sensor capable of outputting a positive / negative detection value is provided, and when the negative detection value is output, it may be determined that the host vehicle is moving backward. . However, since the wheel speed sensor that can output such positive and negative detection values is expensive, the driving assistance device 1 becomes expensive. Further, when the shift lever selected by the shift position sensor 15 is reverse reverse (R), it may be determined that the host vehicle is moving backward. However, when the downhill inclination angle of the road surface is steep, the host vehicle may move forward, and in this case, it may be erroneously determined that the host vehicle is moving backward. Further, when the direction (direction) of the steering angle of the wheel shaft detected by the steering angle sensor 13 by the driver's steering operation changes in the direction opposite to the direction of the yaw rate detected by the yaw rate sensor 14, the host vehicle It may be determined that is moving backward. However, when the steering angle is near zero degrees, it is difficult to determine whether the host vehicle is not moving backward (moving forward) or is moving backward. It is also conceivable to determine the traveling direction of the host vehicle by newly providing a millimeter wave radar device, a camera device, or the like that can measure the relative speed between the host vehicle and the road surface on the lower surface of the vehicle body. However, if a new sensor is separately provided in this way, the driving support device 1 becomes expensive. In addition, since the sensors 13, 14, 15 and the like are not suitable for the functional safety of the host vehicle, these sensors are more expensive to cope with the hazard of ASIL-A.

  According to this embodiment, since the millimeter wave radar device 11 and the camera device 12 used for the backward determination of the host vehicle are compatible with the hazard of ASIL-A, it is possible to perform the backward determination of the host vehicle with high reliability. In addition, the low-cost driving support device 1 can be provided.

  On the other hand, it is also assumed that a stationary object moves when the host vehicle is moving backward. In this case, the reverse determination (step S2) of the host vehicle in the flowchart shown in FIG. 2 may be erroneously determined.

  For example, when an object recognized as a stationary object starts moving backward at twice the vehicle speed of the own vehicle when the own vehicle is moving backward, the backward determination of the own vehicle is erroneously determined. . That is, when the host vehicle is moving backward at a vehicle speed V, if the object moves backward (reverses) at a speed of 2 V, the host vehicle approaches the object at a speed V as a relative speed. Become. In this case, in the reverse determination (step S2) of the own vehicle in the flowchart shown in FIG. 2, it is erroneously determined that the own vehicle approaches the object at the vehicle speed V (not reverse). Therefore, when it is determined that the stationary object recognized at the time of stopping is moving when the host vehicle is moving backward, the moved object is excluded from the determination material for determining the backward driving of the host vehicle.

  As described above, when the movement of the stationary object is started while the host vehicle is moving backward, many other stationary objects extracted by the millimeter wave radar device 11, the camera device 12, and the like, and these stationary objects with respect to the host vehicle. The reverse direction of the host vehicle is determined by comparing the moving directions when the vehicle moves. The moving direction when the stationary object moves is determined based on the relative distance of the stationary object to the host vehicle, the relative speed, and the like.

  As mentioned above, although the best mode for carrying out the present invention has been described using the embodiment, the present invention is not limited to such an embodiment and is within the scope not departing from the gist of the present invention. Various modifications and substitutions can be made to the above-described embodiment.

  In this embodiment, the case where a sensor such as the millimeter wave radar device 11 and the camera device 12 is attached in front of the own vehicle when performing the reverse determination of the own vehicle has been described as an example, but the present invention has this configuration. It is not limited.

  It is not necessary to attach these sensors to the front of the host vehicle. For example, the reverse determination may be performed by configuring the sensor to be attached to the rear of the host vehicle. In this case, an object located behind the host vehicle is recognized as a stationary object. Therefore, the determination conditions are different from those in the case where the sensor is mounted in front of the host vehicle. That is, when the host vehicle gradually approaches the stationary object, it is determined that the host vehicle is moving backward, and when the host vehicle is gradually moving away from the stationary object, the host vehicle is not moving backward (moving forward). Determined).

  Moreover, although the reverse determination of the own vehicle which concerns on this embodiment demonstrated and demonstrated the case where the malfunctioning of PCS control was prevented, this invention is not limited to this. The present invention is not limited to preventing malfunction of PCS control, and can be widely used when performing reverse determination of the host vehicle.

DESCRIPTION OF SYMBOLS 1 Driving assistance apparatus 10 Object detection means 11 Millimeter wave radar apparatus 12 Camera apparatus 20 PCS-ECU
24 Reverse determination unit

Claims (1)

In a driving support device that supports driving of a vehicle,
Object detection means for detecting objects around the vehicle;
When it is determined that the vehicle is gradually moving away from the stationary object based on the position information of the stationary object located in front of the vehicle detected by the object detection means, the vehicle is A driving assistance apparatus comprising: a reverse determination unit that determines that the vehicle is moving backward.

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