JP2009208559A - Collision prevention assistant device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collision prevention assistant device starting automatic braking at the optimum timing. <P>SOLUTION: The collision prevention assistant device is provided with: a collision forecasting means for forecasting the collision of an obstacle existing at a periphery of the vehicle with the vehicle; a gripping state detection means for detecting the gripping state of a rim part of a steering wheel gripped by a driver; an automatic braking timing determination means for determining automatic braking timing for starting automatic braking action not depending on operation of the driver according to the gripping state detected by the gripping state detection means when it is forecast that the obstacle and the vehicle collide; and a braking means for performing braking action at automatic braking timing determined by the automatic braking timing determination means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a collision prevention support device, and more particularly to a collision prevention support device that automatically performs a braking operation when there is a risk that a vehicle will collide with an obstacle.

  Conventionally, when an obstacle around the vehicle is detected and there is a possibility of collision between the vehicle and the obstacle, automatic braking operation (hereinafter referred to as automatic braking) that does not depend on the driver's operation is started. A collision prevention support device has been developed.

  For example, when a vehicle collision prevention support apparatus disclosed in Patent Document 1 detects an obstacle, a minimum distance necessary for avoiding a collision between the vehicle and the obstacle by braking (hereinafter referred to as a braking limit distance). And a minimum distance required to avoid a collision between the vehicle and an obstacle by steering (hereinafter referred to as a steering limit distance) is calculated. FIG. 12 is a graph showing the relationship between the relative speed, the braking limit distance, and the steering limit distance. As shown in FIG. 12, the braking limit distance and the steering limit distance vary according to the magnitude of the relative speed between the vehicle and the obstacle. The collision prevention assistance device performs the following control when the steering limit distance is equal to or less than the braking limit distance (when the relative speed is V1 or more in FIG. 12).

First, the collision prevention support device issues an alarm when the distance between the vehicle and the obstacle (hereinafter referred to as a collision distance) is smaller than a first predetermined value. Then, when there is no steering operation by the driver after the time when the warning is issued, the collision prevention assisting device operates the braking device when the collision distance becomes equal to or less than the braking limit distance. On the other hand, when there is a steering operation by the driver after the time when the alarm is issued, the collision prevention support device starts automatic braking when the collision distance becomes equal to or less than the steering limit distance.
JP 2004-224309 A

  According to the conventional collision prevention support device, the steering limit distance is equal to or less than the braking limit distance even when the driver attempts to avoid the collision by steering and does not intentionally perform the steering operation. Automatic braking is started when the distance becomes less than the braking limit distance. In this way, when the driver is trying to avoid by steering, if the automatic braking is started at a timing that the driver does not want, the driver feels bothered or the steering operation for collision avoidance. The problem of being unable to execute as expected.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a collision prevention support device that starts automatic braking at an optimal timing.

  The present invention employs the following configuration in order to solve the above problems. That is, the first invention includes a collision prediction unit that predicts a collision between an obstacle existing around the vehicle and the vehicle, and a gripping state detection unit that detects a gripping state of the rim portion of the steering wheel gripped by the driver. When the vehicle is predicted to collide with an obstacle, the automatic brake determines the automatic brake timing for starting the automatic braking operation not depending on the operation of the driver according to the gripping state detected by the gripping state detecting means. A collision prevention assisting device including a timing determining unit and a braking unit that executes a braking operation at an automatic brake timing determined by the automatic brake timing determining unit.

  In a second aspect based on the first aspect, the gripping state detecting means includes gripping position detecting means for detecting a gripping position at which the driver grips the rim portion of the steering wheel, and the automatic brake timing determining means is the gripping position. The automatic brake timing is determined according to

  In a third aspect based on the second aspect, the gripping position detecting means detects the gripping position based on a touch input to a touch sensor disposed on the outer surface of the rim portion of the steering wheel.

  In a fourth aspect based on the third aspect, a plurality of touch sensors are arranged on the outer surface of the rim portion of the steering wheel along the circumferential direction of the rim portion.

  According to a fifth invention, in the second invention, the gripping position detecting means includes an imaging device that captures an image including a rim portion of the steering wheel and a driver's hand gripping the rim portion. The grip position is detected.

  In a sixth aspect based on the second aspect, the collision prevention assisting device further includes a rudder angle detecting means for detecting a rudder angle of the steering wheel, and the automatic brake timing determining means is automatically activated according to the rudder angle and the gripping position. Determine the brake timing.

  In a seventh aspect based on the first aspect, the collision prevention assisting device further includes alarm control means for operating the alarm device at a timing earlier than the automatic brake timing when the obstacle and the vehicle are predicted to collide, The gripping state detecting means includes a gripping position change detecting means for detecting a change in the gripping position, and the automatic brake timing determining means detects the change in the gripping position when a change in the gripping position is detected before and after the alarm device operates. The automatic brake timing is relatively delayed as compared with the case where it is not detected.

  In an eighth aspect based on the first aspect, the gripping state detecting means includes gripping hand determining means for determining whether the driver is gripping the rim portion with one hand or both hands, and the automatic brake The timing determination means makes the automatic brake timing relatively earlier when the driver is holding the rim portion with one hand than when the driver is holding the rim portion with both hands.

  According to the first aspect of the present invention, unnecessary automatic braking is not executed when the driver intends to avoid collision by a steering operation, and the driver can make a collision between the vehicle and an obstacle by the steering operation. It can be avoided more safely.

  According to the second invention, for example, when the driver holds the rim portion of the steering wheel at a position where it is difficult to steer, automatic braking is executed at a relatively early timing, and the driver can safely steer. The collision between the vehicle and the obstacle can be avoided by the operation. In addition, when the driver holds the rim portion of the steering wheel at a position where the driver can easily steer, automatic braking is executed at a relatively late timing, and execution of unnecessary automatic braking can be suppressed.

  According to the third invention, the grip position of the rim portion of the steering wheel gripped by the driver can be detected only by the driver gripping the steering device.

  According to the fourth aspect, the grip position of the rim portion of the steering wheel can be determined in more detail.

  According to the fifth aspect, the gripping position of the rim portion of the steering wheel that is gripped by the driver in a non-contact manner based on an image captured by the camera using an imaging device such as a camera as the device that detects the gripping position. Can be detected. Therefore, compared with the case where a contact-type detection device such as a touch sensor is used as a device for detecting the grip position, the device is less likely to be consumed.

  According to the sixth invention, even if the gripping position that is easy for the driver to operate is changed according to the steering angle, the automatic brake timing is determined according to the steering angle and the gripping position. Can be activated.

  According to the seventh aspect of the invention, when the driver recognizes the danger of collision by an alarm and changes the grip position of the rim portion of the steering wheel, the operation of the automatic brake unnecessary for the driver can be suppressed. .

  According to the eighth invention, when the driver holds the rim portion of the steering wheel with one hand and is difficult to steer, the timing for executing the automatic braking operation is earlier, Steering operation for avoiding collision can be performed safely.

(First embodiment)
Hereinafter, with reference to FIG. 1 to FIG. 6, a collision prevention support apparatus according to a first embodiment of the present invention will be described. The collision prevention assisting apparatus according to the first embodiment is automatically operated according to a position where the driver grips the steering wheel (hereinafter referred to as a gripping position) when a vehicle equipped with the apparatus approaches an obstacle or the like. Change the brake timing. The difficulty level of collision avoidance by the steering operation varies depending on the gripping position. Therefore, by changing the automatic brake timing according to the gripping position, the driver can more safely avoid the collision between the vehicle and the obstacle by the steering operation.

  First, an example of a functional configuration of the collision prevention support apparatus will be described with reference to FIG. FIG. 1 is a block diagram illustrating an example of a functional configuration of the collision prevention support apparatus. As shown in FIG. 1, the collision prevention support device includes a millimeter wave radar 11, a touch sensor 121, a touch sensor 122, an ECU (Electrical Control Unit) 13, and a brake control device 14.

  The millimeter wave radar 11 is arranged on a structural material such as a front grill of a vehicle as a sensor for monitoring outside the vehicle. The millimeter wave radar 11 emits an electromagnetic wave having a millimeter wavelength, receives a reflected wave from an obstacle existing around the vehicle, and detects the obstacle. Further, the millimeter wave radar 11 measures the detected distance L from the vehicle to the obstacle and the relative speed V of the vehicle with respect to the obstacle. When the millimeter wave radar 11 detects an obstacle, the millimeter wave radar 11 measures the distance L and the relative speed V, and outputs a signal indicating each measured value to the ECU 13. In addition, as long as the distance L and the relative velocity V can be measured, other measuring instruments such as a laser sensor may be used instead of the millimeter wave radar 11.

  The touch sensor 121 and the touch sensor 122 are respectively disposed on the surface of the rim portion of the steering wheel of the vehicle on which the collision prevention support device is mounted. In the present embodiment, the steering wheel is configured in a substantially annular shape. The touch sensor 121 and the touch sensor 122 are disposed so as to cover the rim surface of the steering wheel as shown in FIG. FIG. 2 is an external view showing an example of a steering wheel on which a touch sensor is arranged. As shown in FIG. 2, the touch sensor 121 is disposed on the upper side of the rim portion while the steering wheel is not rotating. Further, the touch sensor 122 is disposed below the rim portion in a state where the steering wheel is not rotating. As described above, the surface of the rim portion of the steering wheel is covered with either the touch sensor 121 or the touch sensor 122. Therefore, when the driver grasps the rim portion to steer the vehicle, the driver naturally performs touch input to the touch sensor 121 and / or the touch sensor 122. Hereinafter, a state where each touch sensor receives a touch input is referred to as an on state, and a state where no touch input is received is referred to as an off state. Touch sensor 121 and touch sensor 122 output a signal (hereinafter referred to as touch input information) indicating whether the sensor is in an on state or an off state to ECU 13. Note that various types of touch sensors such as an electrostatic type and a pressure-sensitive type can be used for the touch sensor 121 and the touch sensor 122.

  Returning to the description of FIG. 1, the ECU 13 is typically a processing device including an information processing device such as a microcomputer, a storage device such as a memory, and an interface circuit. The ECU 13 calculates a predicted collision time TTC until the obstacle collides with the vehicle based on the distance L and the relative speed V output from the millimeter wave radar. Further, the ECU 13 calculates a threshold TH of the expected collision time TTC based on the touch input information output from the touch sensor 121 and the touch sensor 122. Then, the ECU 13 outputs an instruction to start automatic braking to the brake control device 14 when the value of the time TTC reaches the threshold value TH. Therefore, the larger the threshold value TH, the longer the time from when the vehicle and the obstacle are expected to collide to when automatic braking is started. That is, as the threshold value TH is relatively large, the automatic braking is started at a relatively early point.

  The brake control device 14 is a device that controls the operation of a brake provided in the vehicle. The brake control device 14 performs automatic braking based on an instruction signal output from the ECU 13.

  Next, the processing of the ECU 13 will be described in detail with reference to FIG. FIG. 3 is a flowchart showing an example of processing executed by the ECU 13.

  In step S11, the ECU 13 determines whether or not the ignition switch is ON. If the ECU 13 determines that the ignition switch is ON, the ECU 13 advances the process to step S12. On the other hand, when it is determined that the ignition switch is in a state other than ON (for example, the accessory power supply is on or the ignition switch is off), the ECU 13 ends the process. By the process of step S11, while the ignition switch is ON, the processes from step S12 to step S20 described below are repeated.

In step S12, the ECU 13 calculates an expected collision time TTC. Specifically, the ECU 13 calculates the value of the expected collision time TTC based on the distance L and the relative speed V output from the millimeter wave radar 11 by the following equation.
TTC = L / V
The ECU 13 stores the calculated value of the predicted collision time TTC in the storage device. When the ECU 13 completes the process of step S12, the process proceeds to step S13.

  In step S13, the ECU 13 calculates a steering limit time TS. The steering limit time TS is a minimum time necessary for avoiding a collision between the vehicle and an obstacle by steering. Specifically, the ECU 13 calculates the steering limit time TS based on the relative speed V and the steering limit time calculation table. The steering limit time calculation table is a data table showing the relationship between the steering limit time TS and the relative speed V, and is stored in advance in a storage device provided in the ECU 13. FIG. 4 is a diagram illustrating an example of a steering limit time calculation table. Hereinafter, a method in which the ECU 13 calculates the value of the steering limit time TS will be described with reference to FIG.

  In the steering limit time calculation table shown in FIG. 4, the relative speed V is shown in the first column, and each value of the steering limit time TS corresponding to each value of the relative speed V is shown in the second column of the same row. The ECU 13 searches the steering limit time calculation table for a row indicating the value of the relative speed V acquired from the millimeter wave radar 11, and acquires the value of the steering limit time TS described in the row.

  For example, when the value of the relative speed V is 30 Km / h, the ECU 13 acquires 10 sec as the value of the steering limit time TS based on the steering limit time calculation table shown in FIG.

  Note that the steering limit time calculation table shown in FIG. 4 is an example, and the values of the relative speed V and the steering limit time TS set in the table are not limited to the above. In the above description, the steering limit time TS is calculated from the data table. However, the method for deriving the steering limit time TS is not limited to the above. For example, the steering limit time TS may be calculated based on a mathematical formula indicating the relationship between the steering limit time TS and the relative speed V.

  The ECU 13 stores the calculated steering limit time TS in a storage device. When the ECU 13 completes the process of step S13, the process proceeds to step S14.

  In step S14, the ECU 13 calculates a braking limit time TB. The braking limit time TB is a minimum time required for avoiding a collision between the vehicle and an obstacle by braking. Specifically, the ECU 13 calculates a braking limit time TB based on the relative speed V and a braking limit time calculation table (not shown). The braking limit time calculation table is a data table showing the relationship between the braking limit time TB and the relative speed V, and is stored in advance in a storage device provided in the ECU 13. In the braking limit time calculation table, the value of the braking limit time TB corresponding to each value of the relative speed V is shown. The ECU 13 searches the braking limit time calculation table for the value of the relative speed V acquired from the millimeter wave radar 11, and acquires the value of the braking limit time TB corresponding to the value of the relative speed V. The ECU 13 stores the calculated braking limit time TB in the storage device. When the ECU 13 completes the process of step S14, the process proceeds to step S15.

  In step S15, the ECU 13 determines whether or not the value of the steering limit time TS is smaller than the value of the braking limit time TB. Specifically, the ECU 13 reads the values of the steering limit time TS and the braking limit time TB stored in the storage device, and compares the values. If the ECU 13 determines that the value of the steering limit time TS is smaller than the value of the braking limit time TB, the ECU 13 advances the process to step S16. On the other hand, when the ECU 13 determines that the value of the steering limit time TS is equal to or greater than the value of the braking limit time TB, the ECU 13 proceeds with the process to step S18.

  In step S16, the ECU 13 calculates a threshold value TH. Specifically, the ECU 13 calculates the value of the quick take-out time α according to the grip position. Then, the ECU 13 calculates the value of the threshold value TH by adding the value of the quick start time α to the steering limit time TS. Note that the quick start time α is a numerical value determined based on input information of the touch sensor. Details of the subroutine processing executed in step S16 will be described below with reference to FIG. FIG. 5 is a flowchart showing an example of the subroutine processing in step S16 shown in FIG.

  In step S161, the ECU 13 acquires touch input information output from the touch sensors 121 and 122. Specifically, the ECU 13 acquires a signal indicating whether each of the touch sensors 121 and 122 is in an on state or an off state from the touch sensor 121 and the touch sensor 122, and an input state to each of the touch sensors 121 and 122 Is stored in the storage device. When the ECU 13 completes the process of step S161, the process proceeds to step S162.

  In step S162, the ECU 13 calculates the quick delivery time α. Specifically, the ECU 13 calculates the quick-start time α based on the touch input information acquired in step S161 and the quick-start time calculation table shown in FIG. 6 stored in advance in the storage device. The quick play time calculation table is a data table showing the relationship between the touch input information and the value of the quick play time α. FIG. 6 is a diagram illustrating an example of the quick-start time calculation table. Hereinafter, a method in which the ECU 13 calculates the value of the quick start time α will be described with reference to FIG.

  In the quick-start time calculation table shown in FIG. 6, the input state (on state or off state) to the touch sensor 121 is shown in the first column. Similarly, the input state to the touch sensor 122 is shown in the second column. Then, the value of the quick start time α corresponding to the combination of the input states of the touch sensors 121 and 122 shown in the first and second columns of each row is shown in the third column of the same row. The ECU 13 searches the quick search time calculation table for a line indicating a combination of input states of the touch sensors 121 and 122 that matches the touch input information stored in step S161, and displays the quick search time α indicated in the line. Get the value of.

  It is desirable that the value of the quick pick-up time α set on the quick pick-up time calculation table is set according to the steering difficulty level. Specifically, the steering difficulty level is estimated based on the combination of touch input information of the touch sensors 121 and 122, that is, the gripping position, and the value of the quick start time α is set according to the estimated difficulty level. For example, in FIG. 6, when the touch sensor 121 is on, that is, when the driver is holding the upper part of the steering wheel (see FIG. 2), the driver can sufficiently avoid the collision by steering. Conceivable. In such a case, it is desirable that the value of the quick start time α is set to a relatively small value so that the automatic brake timing is not made earlier than necessary. Therefore, in the quick search time calculation table shown in FIG. 6, when the touch sensor 121 is in the on state, the value of the quick search time α is set to zero.

  On the other hand, when the touch sensor 121 is in the off state and the touch sensor 122 is in the on state, that is, when the driver is holding only the lower part of the steering wheel, it is considered difficult to avoid collision by steering. In such a case, it is desirable that the value of the quick take-out time α is set to a large value as compared with the case where the driver holds the upper part of the steering wheel. Therefore, in the quick search time calculation table shown in FIG. 6, when the touch sensor 121 is in the OFF state and the touch sensor 122 is in the ON state, the value of the quick search time α is set to α1, which is larger than zero. Further, when both the touch sensor 121 and the touch sensor 122 are in the off state, the driver does not grip the steering wheel, so that it is more difficult to avoid collision by steering than when the lower part of the steering wheel is gripped. This is considered a dangerous situation. Therefore, in the early search time calculation table shown in FIG. 6, when both the touch sensor 121 and the touch sensor 122 are in the off state, the value of the quick start time α is set to a value α2 larger than α1.

  In this way, the grip position can be detected from the combination of touch input information. In addition, when the value of the quick start time α is set as described above, automatic braking is started at an early point in a situation where a steering operation by the driver is difficult, and the driver can easily avoid a collision. Note that the early search time calculation table shown in FIG. 6 is an example, and the value of the quick search time α set in the table is not limited to the above.

  Returning to the description of FIG. 5, when the ECU 13 completes the process of step S162, the process proceeds to step S163.

In step S163, the ECU 13 calculates a threshold value TH. Specifically, the ECU 13 reads the value of the steering limit time TS and the value of the quick start time α from the storage device. Then, the ECU 13 calculates the threshold value TH by adding the value of the quick start time α to the steering limit time TS as in the following equation.
TH = TS + α
The ECU 13 stores the calculated threshold value TH in the storage device. When the ECU 13 completes the process of step S163, the ECU 13 returns to the process of the flowchart shown in FIG. 3 and advances the process to step S17.

  As a result of the subroutine processing in step S16 described above, the value of the quick advance time α changes according to the combination of touch input information indicating the grip position. Then, the value of the threshold value TH changes according to the value of the quick take-out time α. Since the automatic brake timing changes according to the value of the threshold value TH, the automatic brake timing can be determined according to the gripping position by the process of step S16.

  In step S17, the ECU 13 determines whether or not the value of the expected collision time TTC is smaller than the threshold value TH. Specifically, the ECU 13 reads the value of the predicted collision time TTC and the value of the threshold value TH from the storage device, and compares the magnitudes. If the ECU 13 determines that the expected collision time TTC value is smaller than the threshold value TH, the process proceeds to step S19. On the other hand, when determining that the value of the predicted collision time TTC is equal to or greater than the threshold value TH, the ECU 13 advances the process to step S20.

  In step S18, the ECU 13 determines whether or not the value of the expected collision time TTC is smaller than the braking limit time TB. Specifically, the ECU 13 reads the value of the estimated collision time TTC and the value of the braking limit time TB from the storage device, and compares the magnitudes. If the ECU 13 determines that the value of the predicted collision time TTC is smaller than the value of the braking limit time TB, the ECU 13 proceeds with the process to step S19. On the other hand, when determining that the value of the predicted collision time TTC is equal to or greater than the value of the braking limit time TB, the ECU 13 advances the process to step S20.

  In step S19, the ECU 13 starts automatic braking. Specifically, the ECU 13 outputs an instruction signal for executing automatic braking to the brake control device 14. When the ECU 13 completes the process of step S19, the process returns to step S11.

  In step S20, the ECU 13 stops the automatic brake. Specifically, the ECU 13 outputs an instruction signal for stopping the automatic brake to the brake control device 14. When the ECU 13 completes the process of step S20, the process returns to step S11.

  According to the processing from step S15 to step S20 described above, the automatic brake timing determination method is changed according to the magnitudes of the steering limit time TS and the braking limit time TB. Hereinafter, the effect will be described.

  When the value of the steering limit time TS is larger than the value of the braking limit time TB, the collision can be avoided if the braking is started when the estimated collision time TTC reaches the braking limit time TB. In such a situation, when the driver is trying to avoid a collision by a brake operation, the driver intends that the time when the estimated collision time TTC reaches the threshold value TH in the process of step S17 is the automatic brake timing. It may feel annoying because the automatic brake is started at an earlier timing. Therefore, when the value of the steering limit time TS is larger than the value of the braking limit time TB, the time when the estimated collision time TTC reaches the braking limit time TB is set as the automatic brake timing in the process of step S18. Thereby, the operation | movement of the above-mentioned unintended automatic brake can be suppressed.

  Even when the steering limit time TS is larger than the braking limit time TB, in order to start the automatic braking at an early point in order to urge the avoidance of the collision by the steering operation, the expected collision time TTC is the braking limit time. The time point at which TB is reached may be used as the automatic brake timing. That is, the processing of step S14, step S15, and step S18 may be omitted.

  As described above, according to the collision prevention assistance device according to the first embodiment, when a vehicle equipped with the device approaches an obstacle or the like, the automatic brake timing can be changed according to the gripping position. The difficulty level of collision avoidance by the steering operation varies depending on the gripping position of the rim portion of the steering wheel gripped by the driver. Therefore, by changing the automatic brake timing according to the gripping position, the automatic brake is started at the timing according to the difficulty level of collision avoidance by the steering operation, and the driver can more safely operate the vehicle and the obstacle by the steering operation. Collisions can be avoided.

(Second Embodiment)
In the first embodiment described above, an example in which two touch sensors are provided in the rim portion of the steering wheel has been described, but the number of touch sensors provided in the steering wheel is not limited to the above. For example, as shown in FIG. 7, twelve touch sensors 221 to 232 may be annularly arranged on the surface of the rim portion of the steering wheel. FIG. 7 is an external view showing an example of a steering wheel on which a touch sensor is arranged. In this way, by increasing the number of touch sensors provided in the steering wheel, the grip position can be detected in more detail, and the automatic brake timing can be determined in more detail.

  Moreover, in 2nd Embodiment, let the width | variety of the circumferential direction of the rim | limb part of the touch sensors 221-232 be a length of a grade smaller than the width | variety which arrange | positioned the driver | operator's both hands. By making the sizes of the touch sensors 221 to 232 as described above, the ECU 13 can determine whether or not the driver is holding the rim portion of the steering wheel with one hand. If the sizes of the touch sensors 221 to 232 are as described above, when the rim portion of the steering wheel is gripped with both hands, at least two touch sensors are always turned on, that is, the touch sensors 221 to 232 are. If there is only one touch sensor in the ON state, it is considered that the driver is holding the steering wheel with one hand. When the driver is holding the steering wheel with one hand, it is considered that the steering operation is difficult, so it is desirable to advance the automatic brake timing. Therefore, in the quick search time calculation table, the value of the quick search time α corresponding to the combination of touch input information in which any one of the touch sensors is on is a touch input in which two or more touch sensors are on. A relatively large value is set compared to the information combination. By setting the value of the quick start time α in this way, when the driver is holding the steering wheel with one hand, the automatic brake is started earlier, and the driver can perform the collision avoidance operation more safely. Can do.

  It should be noted that, in the quick-start time calculation table, only two touch sensors 221 to 232 are in the on state, and the quick-start time corresponding to a combination of touch input information in which the two touch sensors are arranged adjacent to each other. Similarly to the above, the value of α may be set as a relatively large value. By setting the value of the quick start time α in this way, even when the driver holds the rim portion of the steering wheel across the touch sensors with one hand, the automatic brake is started early, and the driver Can perform collision avoidance more safely.

  By the way, when the vehicle is traveling on a curve or the like and the steering wheel is rotated, even if the grip position is the same as when the vehicle is traveling straight, the difficulty of avoiding collision by steering is the same. Not necessarily. That is, it is considered that the gripping position of the steering wheel that is easy for the driver to perform a steering operation varies depending on the steering angle. Therefore, it is desirable that the automatic brake timing is determined in consideration of the steering angle as well as the grip position. Therefore, in the second embodiment, the ECU 13 is connected to a steering angle sensor. The steering angle sensor is a sensor device that detects and outputs the value of the steering angle R of the steering. The value of the rudder angle R is 0 when going straight, and increases by 1 every time the steering wheel rotates 30 degrees clockwise. Further, the ECU 13 stores in advance a plurality of early departure time calculation tables corresponding to the value of the steering angle R in the storage device. Although the details will be described later, the value of the quick-start time α in the plurality of quick-start time calculation tables is set in advance in consideration of the value of the steering angle R and the grip position. Then, the ECU 13 selects an early departure time calculation table corresponding to the detected value of the steering angle R. With the above configuration, the ECU 13 can determine the automatic brake timing more appropriately.

  Hereinafter, the process of the ECU 13 in the second embodiment will be described. The processing of the ECU 13 in the second embodiment is the same as the flowchart shown in FIG. 3, but the processing of the subroutine in step S16 is different. Hereinafter, the processing of the subroutine of step S16 in the second embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing an example of the subroutine processing in step S16 shown in FIG. Of the processes in each step shown in FIG. 8, steps that execute the same processes as those in FIG. 5 are given the same step numbers, and detailed descriptions thereof are omitted.

  In the flowchart shown in FIG. 8, when the ECU 13 completes the process of step S161, the process proceeds to step S261.

  In step S <b> 261, the ECU 13 selects an early withdrawal time calculation table. Specifically, first, the ECU 13 acquires the value of the steering angle R from the steering angle sensor. Next, the quick start time table corresponding to the steering angle R is read from the storage device. In each quick-start time table corresponding to the value of the steering angle R, the value of the quick-start time α is set in advance according to the combination of the steering angle R and touch input information. The combinations of touch input information shown in the respective quick-start time tables corresponding to the value of the steering angle R are common to each other, but even if the combinations of the same touch input information, the value of the quick-start time α corresponding to the combination A different value is set in accordance with the value of the rudder angle R for each quick take-out time table. Hereinafter, a case where the value of the steering angle R is 0 will be described as an example.

  FIG. 9 is a diagram showing an example of an early departure time calculation table corresponding to the steering angle R = 0. In the second embodiment, the number of combinations of touch input information increases as the number of touch sensors increases. Therefore, as shown in FIG. 9, the number of rows and columns in the early search time calculation table in the second embodiment is larger than that in the quick search time calculation table (see FIG. 6) in the first embodiment.

  In general, when the steering angle is R = 0, that is, when the vehicle is traveling straight, the gripping position of the steering wheel that is most easily steered by the driver is within the range from 9 o'clock to 10 o'clock with the short hand of the watch. And within 2 to 3 o'clock. Therefore, the touch sensor 221 (see FIG. 7) is placed in the range from 9 o'clock to 10 o'clock with the short hand of the watch while the vehicle is traveling straight, and the touch is placed in the range from 2 o'clock to 3 o'clock with the short hand of the watch When the sensor 226 (see FIG. 7) is in the on state, it is desirable to delay the automatic brake timing as much as possible. Therefore, in the quick-start time calculation table corresponding to the steering angle R = 0 shown in FIG. 9, the value of the quick-start time α corresponding to the combination of touch input information in which the touch sensor 221 and the touch sensor 226 are on is Set to 0. Note that the value of the quick pick-up time α corresponding to the combination in which the touch sensor 221 and the touch sensor 226 are not in the on-state is set to a value larger than 0 in the quick pick-up time calculation table. For example, the value of the quick advance time α corresponding to the combination in which only the touch sensor 228 and the touch sensor 231 are in the on state is set to α3 larger than 0.

  9 is merely an example, and the value of the quick advance time α when the touch sensor 221 and the touch sensor 226 are in the on state is not the touch sensor 221 and the touch sensor 226 in the on state. As long as the value is relatively smaller than the value of the quick-start time α in this case, the value of the quick-start time α set in the quick-start time calculation table is not limited to the above.

  Returning to the description of FIG. 8, when the ECU 13 completes the process of step S261, the process proceeds to step S162.

  As described above, according to the collision prevention support apparatus according to the second embodiment, the gripping position can be detected in more detail, and the automatic brake timing can be determined in more detail. Further, the automatic brake timing can be changed depending on whether or not the driver holds the steering wheel with one hand. Further, the automatic brake timing can be changed according to the steering angle R and the grip position. As a result, the driver can perform a steering operation for collision avoidance more safely.

(Third embodiment)
In the first embodiment and the second embodiment described above, the ECU 13 has shown an example in which the automatic brake timing is determined according to the gripping position. However, the ECU 13 does not change the gripping position before and after a predetermined time point. The automatic brake timing may be determined according to whether or not the gripping position has changed. Hereinafter, the third embodiment will be described in detail.

  In the third embodiment, the ECU 13 is connected to an alarm device mounted on the vehicle. The alarm device is generally a buzzer that emits an alarm sound. ECU13 outputs the instruction | indication signal which operates an alarm device at the time before starting an automatic brake, when a vehicle and an obstruction approach. If the grip position changes before and after the time when the alarm device is activated, it is considered that the driver has recognized the danger of a collision by the alarm and changed the steering wheel for a steering operation to avoid the collision. Therefore, when the grip position changes before and after the time when the alarm device is operated, the ECU 13 decreases the value of the quick start time α so as not to make the automatic brake timing earlier than necessary so as not to disturb the driver's steering operation. Change to

  Hereinafter, the processing of the ECU 13 in the third modification will be described with reference to FIG. FIG. 10 is a flowchart showing an example of processing executed by the ECU 13. Of the steps shown in FIG. 10, steps that execute the same processing as in FIG. 3 are given the same step numbers, and detailed descriptions thereof are omitted.

  In the flowchart shown in FIG. 10, when the ECU 13 completes the process of step S11, the process proceeds to step S31.

  In step S31, the ECU 13 acquires touch input information. Specifically, the ECU 13 acquires a signal indicating whether each touch sensor is on or off, and stores the state of each touch sensor in the storage device. When the ECU 13 completes the process of step S161, the process proceeds to step S12.

  When the ECU 13 completes the process of step S12, the process proceeds to step S32.

  In step S32, the ECU 13 determines whether or not the value of the predicted collision time TTC is smaller than the value of the warning time TA. Specifically, the ECU 13 reads the value of the predicted collision time TTC stored in the storage device and the value of the alarm time TA that is a constant stored in the storage device in advance, and compares the values. If the ECU 13 determines that the value of the predicted collision time TTC is smaller than the value of the warning time TA, the ECU 13 proceeds with the process to step S33. On the other hand, if the ECU 13 determines that the value of the predicted collision time TTC is equal to or greater than the value of the warning time TA, the process proceeds to step S34.

  In step S33, the ECU 13 starts an alarm. Specifically, the ECU 13 outputs an instruction signal for starting an alarm operation to the alarm device. When the ECU 13 completes the process of step S33, the process proceeds to step S13.

  In step S34, the ECU 13 stops the alarm. Specifically, the ECU 13 outputs an instruction signal for stopping the alarm operation to the alarm device. When the ECU 13 completes the process of step S34, the process returns to step S11.

  By the processing from step S32 to step S34 described above, the alarm device operates to issue an alarm when the estimated collision time TTC reaches the alarm time TA.

  In step S15, when the value of the steering limit time TS is smaller than the value of the braking limit time TB, the ECU 13 advances the process to step S35.

  In step S35, the ECU 13 calculates a threshold value TH. Specifically, the ECU 13 acquires touch input information after the alarm is issued. Then, the touch input information before and after the alarm is issued is compared, and when the touch input information is changed, the threshold TH is calculated by setting the value of the quick start time α to 0. Details of the subroutine processing in step S35 will be described below with reference to FIG. FIG. 11 is a flowchart showing an example of the subroutine processing in step S35. Of the steps shown in FIG. 11, steps that execute the same processing as in FIG. 5 are given the same step numbers, and detailed descriptions thereof are omitted.

  In step S161, the ECU 13 acquires touch input information. The specific processing is as described above. Here, the ECU 13 stores the touch input information acquired in step S161 in a different area from the touch input information acquired in step S31 (see FIG. 10). Store in the device. When the ECU 13 completes the process of step S161, the process proceeds to step S361.

  In step S361, the ECU 13 determines whether or not the gripping position has changed before and after the alarm issuance. Specifically, the ECU 13 compares whether the touch input information acquired in the immediately preceding step S161 is different from the touch input information acquired in step S31. If the touch input information acquired in the immediately preceding step S161 is different from the touch input information acquired in step S31, the ECU 13 determines that the grip position has changed before and after the alarm is issued, and the process proceeds to step S362. Proceed to On the other hand, if the touch input information acquired in the immediately preceding step S161 matches the touch input information acquired in step S31, the ECU 13 determines that the grip position has not changed before and after the alarm is issued, and the process is stepped. Proceed to S162.

  In step S362, the ECU 13 sets the value of the quick take-out time α to zero. Note that the value of the quick start time α set in step S362 is not limited to 0 as long as automatic braking can be started at a timing that does not interfere with the driver's steering operation. When ECU 13 completes the process of step S362, the process proceeds to step S163.

  By the processes in steps S31, S32, and S35 described above, a change in the grip position before and after the alarm is generated can be detected, and the value of the threshold TH can be calculated in accordance with the change.

  As described above, according to the collision prevention support device according to the third embodiment, the automatic brake timing can be changed according to whether or not the gripping position has changed before and after the time when the alarm device is operated. Therefore, when the driver is conscious of avoiding a collision by an alarm, unnecessary automatic brake operation can be suppressed.

  In the first to third embodiments described above, the steering wheel is provided with a plurality of touch sensors that detect only the presence or absence of touch input. A detectable touch sensor may be used. With such a touch sensor, if the entire rim surface of the steering wheel is used as one input surface, a detailed gripping position can be detected with a small number of parts.

  In the first to third embodiments, the example in which the grip position is detected based on the input to the touch sensor disposed on the steering wheel has been described. However, the method for detecting the grip position is the touch sensor. It is not restricted to the method of using. For example, a situation where the driver holds the steering wheel with a camera mounted in the vehicle may be photographed, and the gripping position may be detected based on an image photographed by the camera (hereinafter referred to as a camera image). Thus, when detecting a holding position based on a camera image, ECU13 acquires a camera image. Then, the ECU 13 detects the gripping position of the acquired camera image by recognizing the position of the steering wheel and the position of the driver's hand in the camera image.

  The anti-collision assistance device according to the present invention can be used as an anti-collision assistance device that can determine the timing for starting an automatic braking operation in accordance with the gripping state of the rim portion of the steering wheel gripped by the driver.

Block diagram showing an example of the functional configuration of the collision prevention support device External view showing an example of a steering wheel in which a touch sensor is arranged The flowchart which shows an example of the process performed by ECU The figure which shows an example of a steering limit time calculation table The flowchart which shows an example of the subroutine process of step S16 shown in FIG. The figure which shows an example of the quick-earning time calculation table External view showing an example of a steering wheel in which a touch sensor is arranged The flowchart which shows an example of the subroutine process of step S16 shown in FIG. The figure which showed an example of the quick take-off time calculation table corresponding to the steering angle R = 0 The flowchart which shows an example of the process performed by ECU The flowchart which shows an example of the subroutine process of step S35 shown in FIG. Graph showing the relationship between relative speed, braking limit distance and steering limit distance

11 Millimeter wave radar 13 ECU
14 Brake control devices 121, 122, 221-232 Touch sensor

Claims (8)

A collision prediction means for predicting a collision between an obstacle existing around the vehicle and the vehicle;
Gripping state detecting means for detecting the gripping state of the rim portion of the steering wheel gripped by the driver;
When it is predicted that the obstacle and the vehicle will collide, automatic brake timing determining means for determining automatic brake timing for starting automatic braking according to the gripping state;
A collision prevention support device comprising: brake means for executing the automatic brake at the automatic brake timing. The grip state detection means includes a grip position detection means for detecting a grip position where a driver grips the rim portion of the steering wheel,
The collision prevention assisting apparatus according to claim 1, wherein the automatic brake timing determining means determines the automatic brake timing according to the gripping position.   The collision prevention support apparatus according to claim 2, wherein the grip position detection unit detects the grip position based on a touch input to a touch sensor disposed on an outer surface of a rim portion of the steering wheel.   The collision prevention support device according to claim 3, wherein a plurality of the touch sensors are arranged on an outer surface of the rim portion of the steering wheel along a circumferential direction of the rim portion. The grip position detection means includes an imaging device that captures an image including a rim portion of the steering wheel and a driver's hand gripping the rim portion,
The collision prevention support apparatus according to claim 2, wherein the grip position is detected based on the image. A steering angle detecting means for detecting a steering angle of the steering wheel;
The collision prevention support apparatus according to claim 2, wherein the automatic brake timing determination unit determines the automatic brake timing according to the steering angle and the grip position. When it is predicted that the obstacle and the vehicle will collide, further comprising an alarm control means for operating an alarm device at a timing earlier than the automatic brake timing,
The gripping state detection means includes gripping position change detection means for detecting a change in the gripping position,
The automatic brake timing determining means relatively delays the automatic brake timing when a change in the gripping position is detected before and after the alarm device is operated, compared to a case in which a change in the gripping position is not detected; The collision prevention support device according to claim 1. The gripping state detection means includes gripping hand determination means for determining whether the driver is gripping the rim part with one hand or with both hands,
The automatic brake timing determination means makes the automatic brake timing relatively earlier when a driver is holding the rim part with one hand than when the driver is holding the rim part with both hands. The collision prevention support apparatus according to 1.

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