JP2012224119A - Brake control apparatus for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake control apparatus for a vehicle, in which an automatic brake can be properly released in response to the driver's intention.SOLUTION: The brake control apparatus for the vehicle automatically brakes an own vehicle depending on a risk of collision of the own vehicle with an obstacle. The apparatus includes: a collision determination device that determines whether the risk of collision of the own vehicle with the obstacle is high; an automatic brake device that controls a braking device of the own vehicle and automatically generates a braking force when the collision determination device determines that the risk of collision of the own vehicle with the obstacle is high; and an automatic brake-release device that stops the automatic generation of the braking force by the automatic brake device, on the basis of operation frequencies of an accelerator pedal of the own vehicle by the own vehicle driver.

Description

  The present invention relates to a vehicle brake control device, and more particularly to a vehicle brake control device capable of releasing automatic braking in response to an operation of a driver.

  2. Description of the Related Art Conventionally, in order to avoid a collision between a vehicle and an obstacle, a device that performs so-called automatic braking when a risk of collision between the vehicle and the obstacle increases has been developed. Automatic braking refers to braking control that controls a vehicle braking device regardless of a driver's operation to generate an automatic braking force on the host vehicle.

  A vehicular braking control apparatus that performs the automatic braking as described above is disclosed in Patent Document 1. The vehicle brake control device disclosed in Patent Literature 1 determines whether or not the driver intends to release automatic braking in accordance with an operation of an accelerator pedal or the like by the driver. If it is determined that there is an intention to cancel the automatic braking, the automatic braking is stopped. According to such a process, when the automatic braking is executed at an unnecessary timing, the unnecessary automatic braking can be stopped by the judgment of the driver.

JP 2003-17581 A

  In the vehicle brake control device according to Patent Document 1, whether the automatic braking is to be released according to how much the accelerator opening is increased at the present time with reference to the accelerator opening at the time when the automatic braking is started. It is determined whether or not. In such a process, even if the driver does not intend to release automatic braking, it is considered that the driver is trying to release automatic braking when the accelerator opening becomes relatively large, and automatic braking is released. It may be done. In other words, the conventional technology has not been able to stop the automatic braking with the full intention of the driver.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vehicle brake control device that can automatically release automatic braking according to the driver's intention.

  In order to solve the above problems, the present application adopts the following configuration. That is, the first invention is a vehicle braking control device that automatically brakes the host vehicle in accordance with the risk of collision between the host vehicle and an obstacle, and the risk of collision between the host vehicle and the obstacle. The collision determination means for determining whether or not the vehicle is high, and if the collision determination means determines that the risk of collision between the host vehicle and the obstacle is high, the braking force of the host vehicle is controlled automatically An automatic braking means for generating the automatic braking means, and an automatic braking releasing means for stopping the automatic braking force generation by the automatic braking means based on the frequency of operation of the accelerator pedal of the own vehicle by the driver of the own vehicle. This is a braking control device for a vehicle.

  In a second aspect based on the first aspect, the automatic braking release means determines whether or not the driver of the own vehicle has performed a continuous stepping operation that continuously depresses the accelerator pedal of the own vehicle at a high frequency. The vehicle control device includes an accelerator opening detecting means for detecting an accelerator opening of the host vehicle, and an opening gradient calculating means for calculating a change amount of the accelerator opening per predetermined time as an accelerator opening gradient. The continuous stepping operation determination means determines whether or not the continuous stepping operation has been performed based on a magnitude relationship between the accelerator opening gradient and a predetermined gradient threshold value.

  In a third aspect based on the second aspect, the gradient threshold includes a first opening gradient threshold and a second opening gradient threshold smaller than the first gradient gradient threshold, The operation determining means determines that the driver has performed an operation of depressing the accelerator pedal when the accelerator opening gradient exceeds the first gradient threshold, and the driver determines that the accelerator opening gradient is below the second gradient threshold. When it is determined that the operation of depressing the accelerator pedal has been performed, and when it is determined that the operation of depressing the accelerator pedal and the operation of loosening the accelerator pedal have been alternately performed more than a predetermined number of times, it is determined that the continuous depressing operation has been performed. Features.

  According to a fourth aspect of the present invention, in any one of the second to third aspects of the invention, a vehicle speed detection unit that detects a travel speed of the host vehicle, and a slope threshold calculation that calculates a slope threshold value based on the travel speed of the host vehicle. And a means.

  According to a fifth invention, in any one of the second to third inventions, a relative speed calculation unit that detects a relative speed between the host vehicle and the obstacle, and a gradient threshold value calculation that calculates a gradient threshold value based on the relative speed. And a means.

  According to a sixth aspect of the invention, in any one of the second to third aspects of the invention, a collision prediction time calculation unit that calculates a time required for the collision of the host vehicle and a vehicle following the host vehicle as a collision prediction time; Gradient threshold value calculation means for calculating a gradient threshold value based on the predicted time is further provided.

  According to a seventh aspect of the invention, in any one of the second to third aspects, the automatic braking time calculating means calculates the elapsed time from the time when the automatic braking means starts generating the automatic braking force as the braking time. And a gradient threshold value calculating means for calculating a gradient threshold value based on the length of the braking time.

  In an eighth aspect of the present invention based on any one of the first to seventh aspects, the automatic braking release means continues to determine whether or not the driver of the host vehicle has performed a continuous stepping operation to maintain a state where the driver has depressed the accelerator pedal. It includes a stepping operation determining means.

  A ninth invention further comprises an accelerator opening detecting means for detecting an accelerator opening of the host vehicle according to the eighth invention, wherein the accelerator operation determining means has the accelerator opening of the host vehicle exceeding a predetermined opening threshold. It is characterized in that it is determined that a continuous stepping operation has been performed when the state has continued for a predetermined time or more.

  According to a tenth aspect, in the ninth aspect, at least any one of a traveling speed of the own vehicle, a relative speed of the obstacle with respect to the own vehicle, and a predicted collision time estimated to be required until the own vehicle and the obstacle collide. Vehicle state quantity detecting means for detecting one of them, and opening degree threshold value calculating means for calculating an opening degree threshold value based on at least one of travel speed, relative speed, and predicted collision time. Features.

  According to the first invention, for example, when the accelerator pedal is frequently operated by the driver, automatic braking can be stopped. If the driver frequently operates the accelerator pedal while automatic braking is being executed, the driver is likely to want to accelerate the vehicle. Therefore, according to such a process, it is possible to release the automatic braking qualifyingly based on the intention of the driver to release the automatic braking.

  According to the second invention, automatic braking can be stopped when there is an operation of depressing the accelerator pedal continuously at a high frequency. Further, it is possible to determine whether or not there has been an operation of depressing the accelerator pedal continuously by a simple process using a threshold value.

  According to the third aspect of the present invention, after the driver depresses the accelerator pedal, it is possible to reliably detect an operation of once loosening and accurately detect whether or not there has been a continuous depressing operation.

  According to the fourth invention, for example, when the traveling speed of the host vehicle is relatively high, that is, when automatic braking is erroneously started, it is considered that there is a high risk that the host vehicle will collide with the following vehicle. In the situation, the gradient threshold value can be calculated so that it is easy to determine that the continuous stepping operation has been performed. That is, it is possible to easily cancel the automatic braking in a situation where it is considered necessary to cancel the automatic braking.

  According to the fifth invention, for example, it is considered that the situation in which the relative speed of the obstacle with respect to the own vehicle is relatively large in the direction approaching the own vehicle, that is, the risk that the own vehicle collides with the obstacle is increased. Under certain circumstances, it is possible to make it difficult to cancel the automatic braking by increasing the gradient threshold. That is, it is possible to make it difficult to cancel the automatic braking in a situation where it is considered necessary to execute the automatic braking.

  According to the sixth invention, for example, in a situation where the predicted time of collision between the own vehicle and the preceding vehicle is relatively short, that is, in a situation where the possibility that the own vehicle will collide with the preceding vehicle is relatively high, the gradient It is possible to make it difficult to cancel the automatic braking by increasing the threshold. That is, it is possible to make it difficult to cancel the automatic braking in a situation where it is considered necessary to execute the automatic braking.

  According to the seventh aspect, the gradient threshold value can be calculated according to the length of the braking time during which automatic braking is performed. It can be considered that the degree of request for releasing the automatic braking by the driver differs immediately after the start of the automatic braking and after a certain time has elapsed after the start. Therefore, by calculating the gradient threshold according to the length of the braking time, it is possible to easily release (or make it difficult to release) the automatic braking according to such a driver's request.

  According to the eighth aspect of the invention, the automatic braking can be released when the driver performs a continuous depressing operation that maintains the state where the driver depresses the accelerator pedal of the host vehicle. If the driver performs such a continuous stepping operation while automatic braking is being performed, the driver is likely to want to accelerate the vehicle. Therefore, according to such a process, automatic braking can be canceled when it is clear that the driver has an intention to cancel automatic braking.

  According to the ninth aspect, it is possible to determine whether or not there has been a continuous stepping operation by a simple process using a threshold value.

  According to the tenth aspect, it is possible to easily cancel the automatic braking according to the traveling state of the host vehicle or the state of the host vehicle and the obstacle. For example, in a situation where the traveling speed of the host vehicle is relatively high, a continuous stepping operation is performed in a situation where there is a high risk that the host vehicle will collide with a succeeding vehicle if automatic braking is erroneously started. The opening degree threshold value can be calculated so that it is easy to determine that it has occurred. That is, it is possible to easily cancel the automatic braking in a situation where it is considered necessary to cancel the automatic braking.

An example of a block diagram showing a configuration of a vehicle brake control device 1 according to an embodiment of the present invention An example of a flowchart showing details of processing executed by the collision determination ECU 20 according to the embodiment of the present invention An example of a flowchart showing details of a continuous stepping operation determination process executed by the collision determination ECU 20 The figure which shows an example of the function for calculating the opening degree threshold value Kth An example of a flowchart showing details of continuous stepping operation determination processing executed by the collision determination ECU 20 The figure which shows a mode that the brake control apparatus 1 for vehicles detects a driver's continuous stepping operation, and cancels | releases automatic braking. The figure which shows a mode that the vehicle brake control apparatus 1 detects a driver's continuous stepping operation, and cancels | releases automatic braking.

  Hereinafter, a vehicle brake control device 1 according to an embodiment of the present invention will be described. The vehicle braking control device 1 is a device that is mounted on the host vehicle and controls the execution state of automatic braking for the host vehicle. Automatic braking refers to braking control that controls a vehicle braking device regardless of a driver's operation to generate an automatic braking force on the host vehicle. The vehicle braking control device 1 performs automatic braking when the risk of collision between the host vehicle and an obstacle is high, and an operation for the driver to release automatic braking (hereinafter referred to as automatic braking releasing operation). Stop automatic braking when done.

  First, the configuration of the vehicle brake control device 1 will be described with reference to FIG. FIG. 1 is an example of a block diagram showing the configuration of the vehicle brake control device 1. As shown in FIG. 1, the vehicle brake control device 1 includes a radar device 11, an accelerator device 12, a vehicle speed sensor 13, an acceleration sensor 14, a collision determination ECU 20, and a brake control ECU 30.

  The radar device 11 is a device that detects an obstacle by transmitting an electromagnetic wave around the vehicle and receiving the electromagnetic wave reflected by the obstacle. When the radar device 11 detects an obstacle, the radar device 11 detects the obstacle information for the host vehicle. Specifically, the radar device 11 detects relative speed Vr (km / h) with respect to the obstacle own vehicle and a distance L (km) from the obstacle to the own vehicle as the obstacle traveling information. The radar apparatus 11 transmits data indicating the relative speed Vr and the distance L to the collision determination ECU 20. As a method for the radar device 11 to detect the relative speed Vr and the distance L, any conventionally known method may be used.

  The accelerator device 12 is a device that accepts an input operation from the driver of the host vehicle and accelerates the host vehicle. The driver performs the input operation by stepping on an accelerator pedal provided in the accelerator device 12. The accelerator device 12 transmits to the collision determination ECU 20 a value of the accelerator opening K that increases or decreases according to the amount of depression of the accelerator pedal by the driver. It is assumed that the accelerator opening K increases as the driver depresses the accelerator pedal deeper.

  The vehicle speed sensor 13 is a sensor device that detects the traveling speed Vs (km / h) of the host vehicle. The vehicle speed sensor 13 transmits data indicating the detected traveling speed Vs of the host vehicle to the collision determination ECU 20. In addition, as a method for the vehicle speed sensor 13 to detect the traveling speed Vs, any conventionally known method may be used.

The acceleration sensor 14 is a sensor device that detects the acceleration AC (m / s ² ) of the host vehicle. The acceleration sensor 14 transmits data indicating the detected acceleration AC of the host vehicle to the collision determination ECU 20. As a method for the acceleration sensor 14 to detect the acceleration AC, any conventionally known method may be used.

  The collision determination ECU 20 is a control device that instructs the brake control ECU 30 to execute and stop the braking operation based on information obtained from the radar device 11, the accelerator device 12, the vehicle speed sensor 13, and the acceleration sensor 14. The collision determination ECU 20 is typically a control device including an information processing device such as a CPU (Central Processing Unit), a storage device such as a memory, an interface circuit, and the like. Details of the process executed by the collision determination ECU 20 will be described later.

  The brake control ECU 30 is a control device that controls the operation of the brake device of the host vehicle. The brake control ECU 30 operates the brake device of the host vehicle in accordance with an instruction signal from the collision determination ECU 20 and an input operation via a driver's brake pedal (not shown). When the brake control ECU 30 receives an instruction signal to start automatic braking from the collision determination ECU 20, the brake control ECU 30 operates the brake device regardless of whether the driver operates the brake pedal, and automatically generates a braking force on the host vehicle. Let

  Next, processing executed by the collision determination ECU 20 will be described. The collision determination ECU 20 starts automatic braking based on information obtained from the radar device 11 or the like. Then, the collision determination ECU 20 determines whether or not the driver has performed an automatic braking release operation based on the information obtained from the accelerator device 12 or the like, and releases the automatic braking based on the determination result. Hereinafter, the process executed by the collision determination ECU 20 will be described in detail with reference to FIG. FIG. 2 is an example of a flowchart showing details of processing executed by the collision determination ECU 20 according to the embodiment of the present invention. For example, when the user turns on the operation of the automatic braking system using an input device (not shown) provided in the host vehicle, the collision determination ECU 20 executes the process of FIG. When the collision determination ECU 20 starts the process of the flowchart of FIG. 2, first, the collision determination ECU 20 executes the process of step S <b> 1.

  In step S1, the collision determination ECU 20 determines whether an obstacle has been detected. Specifically, the collision determination ECU 20 determines that an obstacle has been detected when information on the obstacle is received from the radar device 11, and advances the processing to step S2. On the other hand, if the collision determination ECU 20 has not received information on the obstacle from the radar device 11, it determines that no obstacle has been detected, and advances the process to step S8.

In step S2, the collision determination ECU 20 determines whether or not there is a high risk of collision between the obstacle and the host vehicle. Specifically, first, the collision determination ECU 20 calculates a time that is expected to be required until the obstacle collides with the host vehicle (hereinafter referred to as a collision prediction time TTC). More specifically, the collision determination ECU 20 uses the relative speed Vr and the distance L received from the radar device 11 in step S1, and calculates the collision prediction time TTC based on the equation (1).
TTC = L / Vr (1)
Next, the collision determination ECU 20 determines whether or not the predicted collision time TTC is shorter than a predetermined threshold value TTCth. When the collision prediction time TTC is shorter than the predetermined threshold value TTCth, the collision determination ECU 20 determines that the risk of collision between the obstacle and the host vehicle is high, and proceeds to step S3 to start automatic braking. To do. On the other hand, when the collision prediction time TTC is longer than the predetermined threshold value TTCth, the collision determination ECU 20 determines that the risk of collision between the obstacle and the host vehicle is low, and advances the process to step S8. Note that the process of step S2 is an example, and the collision determination ECU 20 has a high risk of collision between the obstacle and the host vehicle.

  In step S3, the collision determination ECU 20 starts automatic braking. Specifically, the collision determination ECU 20 transmits an instruction signal for starting automatic braking to the brake control ECU 30. When the collision determination ECU 20 completes the process in step S3, the collision determination ECU 20 advances the process to step S4, and determines whether or not the driver is performing an operation of releasing automatic braking.

  In step S4, the collision determination ECU 20 executes a continuous stepping operation determination process. The continuous stepping operation process is a process for determining whether or not a continuous stepping operation, which is one of the automatic braking release operations, has been performed by the driver. The continuous depressing operation is an operation for maintaining the state where the driver of the own vehicle depresses the accelerator pedal. The collision determination ECU 20 stops the automatic braking when it is determined that the driver has performed the continuous stepping operation. Hereinafter, with reference to FIG. 3, the continuous stepping operation determination process executed by the collision determination ECU 20 will be described. FIG. 3 is an example of a flowchart showing details of the continuous stepping operation determination process executed by the collision determination ECU 20. When the collision determination ECU 20 starts the process of the flowchart of FIG. 3, first, the collision determination ECU 20 executes the process of step S <b> 41.

  In step S <b> 41, the collision determination ECU 20 acquires the acceleration AC from the acceleration sensor 14. When the collision determination ECU 20 completes the process of step S41, the process proceeds to step S42.

  In step S42, the collision determination ECU 20 determines whether or not the acceleration AC is equal to or less than the acceleration threshold ACth. The acceleration threshold ACth is a constant value stored in advance in the storage device of the collision determination ECU 20 and is, for example, zero. That is, in step S42, the collision determination ECU 20 determines whether or not the acceleration AC of the host vehicle is negative. When the collision determination ECU 20 determines that the acceleration AC is equal to or less than the acceleration threshold ACth, the collision determination ECU 20 advances the process to step S43. On the other hand, when the collision determination ECU 20 determines that the acceleration AC is greater than the acceleration threshold ACth, the collision determination ECU 20 advances the process to step S51.

  When automatic braking is started, there is a high possibility that the acceleration AC is negative. Therefore, it is possible to determine whether or not there is a high possibility that the automatic braking is being executed by the processing in step S42 described above. In the situation where automatic braking is not being performed, the process for determining whether or not there is an automatic braking release operation is unnecessary, so it is unnecessary to perform the following process only when there is a high possibility that automatic braking is being performed. Execution of processing can be suppressed.

  In step S <b> 43, the collision determination ECU 20 acquires the traveling speed Vs from the vehicle speed sensor 13. When the collision determination ECU 20 completes the process of step S43, the process proceeds to step S44.

  In step S44, the collision determination ECU 20 calculates the opening degree threshold value Kth based on the traveling speed Vs acquired in step S43. The opening degree threshold value Kth is a threshold value for the accelerator opening degree K for determining whether or not the driver of the host vehicle has executed a continuous stepping operation. For example, the collision determination ECU 20 calculates the opening threshold value Kth as a smaller value as the traveling speed Vs increases. More specifically, the opening degree threshold value Kth is calculated based on a function having the travel speed Vs as a variable as shown in FIG. FIG. 4 is a diagram illustrating an example of a function for calculating the opening degree threshold value Kth. Note that the process of step S44 is an example, and if the collision determination ECU 20 can calculate the opening threshold value Kth based on the traveling speed Vs, the opening threshold value Kth is calculated using any conventionally known method. Also good. When the collision determination ECU 20 completes the process of step S44, the process proceeds to step S45.

  By calculating the opening degree threshold value Kth as in step S44, there is a risk that the host vehicle will collide with the following vehicle when the traveling speed Vs is relatively high, that is, when automatic braking is erroneously started. In a situation considered to be high, the opening degree threshold value Kth can be calculated so that it is easy to determine that the continuous stepping operation has been performed, so that the automatic braking can be easily released.

  In step S <b> 45, the collision determination ECU 20 acquires the accelerator opening K from the accelerator device 12. When the collision determination ECU 20 completes the process of step S45, the process proceeds to step S46.

  In step S46, the collision determination ECU 20 determines whether or not the accelerator opening K is equal to or larger than the opening threshold Kth. If the collision determination ECU 20 determines that the accelerator opening K is equal to or greater than the opening threshold Kth, the collision determination ECU 20 advances the process to step S47. On the other hand, when the collision determination ECU 20 determines that the accelerator opening K is less than the opening threshold Kth, the process proceeds to step S48.

  In step S47, the collision determination ECU 20 increments the timer value T. The timer value T is a numerical value indicating the duration of the state in which the accelerator opening K exceeds the opening threshold Kth. The timer value T is a variable stored in the storage device of the collision determination ECU 20, and the initial value is preset to, for example, zero. The collision determination ECU 20 adds a predetermined constant value (for example, 1) to the timer value T in this step S47. When the collision determination ECU 20 completes the process of step S47, the process proceeds to step S49.

  In step S48, the collision determination ECU 20 resets, that is, initializes the timer value T. When the collision determination ECU 20 completes the process of step S48, the process proceeds to step S49.

  In step S49, the collision determination ECU 20 determines whether or not the timer value T is greater than or equal to the timer threshold value Tth. When collision determination ECU 20 determines that timer value T is equal to or greater than timer threshold value Tth, the process proceeds to step S50. On the other hand, when the collision determination ECU 20 determines that the timer value T is less than the timer threshold value T, the process proceeds to step S51.

  In step S50, the collision determination ECU 20 sets the continuous stepping flag on. The continuous stepping flag is flag data indicating that there has been a continuous stepping operation when the flag is set to an on state, and that there is no continuous stepping operation when the flag is set to an off state. is there. It is assumed that the continuous stepping flag is set to an off state in the initial state. When the collision determination ECU 20 completes the process of step S50, the process proceeds to step S5 of FIG.

  In step S51, the collision determination ECU 20 sets the continuation stepping flag to an off state. When the collision determination ECU 20 completes the process of step S51, the process proceeds to step S5 of FIG.

  According to the above-mentioned continuous stepping operation determination process, when the state where the accelerator opening K exceeds the opening threshold value Kth continues for a predetermined time, it is determined that there is a continuous stepping operation, and the continuous stepping flag is set to the on state. .

  In step S5, the collision determination ECU 20 determines whether or not the continuation stepping flag is on. If the collision determination ECU 20 determines that the continuation stepping flag is on, the process proceeds to step S8. On the other hand, when the collision determination ECU 20 determines that the continuation stepping flag is OFF, the process proceeds to step S6.

  In step S6, the collision determination ECU 20 executes a continuous stepping operation determination process. The continuous depressing operation process is a process for determining whether or not the continuous depressing operation, which is one of the automatic braking release operations, has been performed by the driver. In the continuous depressing operation, the driver of the own vehicle continuously presses the accelerator pedal of the own vehicle. This is an operation to step on. Hereinafter, with reference to FIG. 5, the continuous stepping operation determination process executed by the collision determination ECU 20 will be described. FIG. 5 is an example of a flowchart showing details of the continuous stepping operation determination process executed by the collision determination ECU 20. When the collision determination ECU 20 starts the process of the flowchart of FIG. 5, first, the collision determination ECU 20 executes a process of step S61.

  In step S <b> 61, the collision determination ECU 20 acquires the traveling speed Vs from the vehicle speed sensor 13. Note that if the travel speed Vs has already been acquired in step S2, the process in step S61 may be omitted. When the collision determination ECU 20 completes the process of step S61, the process proceeds to step S62.

  In step S62, the collision determination ECU 20 calculates a first gradient threshold value Dth1 based on the traveling speed Vs. The first gradient threshold value Dth1 is a threshold value for determining whether or not the driver has performed an operation of depressing the accelerator pedal. For example, the collision determination ECU 20 calculates the first gradient threshold Dth1 as a smaller value as the traveling speed Vs increases. Specifically, the collision determination ECU 20 calculates the first gradient threshold value Dth1 in the same manner as in step S44. When the collision determination ECU 20 completes the process of step S62, the process proceeds to step S63.

  By calculating the first gradient threshold value Dth1 as in step S66, there is a risk that the host vehicle will collide with a succeeding vehicle when the traveling speed Vs is relatively high, that is, when automatic braking is erroneously started. In a situation in which it is considered that is high, it is possible to calculate the first gradient threshold value Dth1 so that it is easy to determine that the continuous stepping operation has been performed, and to easily release the automatic braking.

  In step S63, the collision determination ECU 20 calculates a second gradient threshold value Dth2. The second gradient threshold value Dth2 is a threshold value for determining whether or not the driver has performed an operation of relaxing the depression of the accelerator pedal. The collision determination ECU 20 calculates the second gradient threshold Dth2 as a value smaller than the first gradient threshold Dth1. The collision determination ECU 20 calculates the second gradient threshold value Dth2 by, for example, subtracting a predetermined constant from the first gradient threshold value Dth1. Note that the above calculation method is an example, and the collision determination ECU 20 may use any conventionally known method to calculate the second gradient threshold value as long as the second gradient threshold value Dth2 can be calculated as a value smaller than the first gradient threshold value Dth1. Dth2 may be calculated. When the collision determination ECU 20 completes the process of step S63, the process proceeds to step S64.

In step S64, the collision determination ECU 20 calculates an accelerator opening gradient D. The accelerator opening gradient D is a value indicating the amount of change in the accelerator opening K per unit time. Specifically, the collision determination ECU 20 first acquires the current accelerator opening K and stores it in its own storage device. Next, the collision determination ECU 20 sets the accelerator opening K stored at the time before a predetermined time Δt as K2, and sets the accelerator opening K based on the equation (2) when the current accelerator opening K is K1. A degree gradient D is calculated.
D = (K1-K2) / Δt (2)
When the collision determination ECU 20 completes the process of step S64, the process proceeds to step S65.

  In step S65, the collision determination ECU 20 determines whether or not the stepping flag is on. The depression flag is flag data that is set to an on state when the driver performs an operation of depressing the accelerator pedal, and is then set to an off state when the driver performs an operation of loosening the depression. If the collision determination ECU 20 determines that the stepping flag is on, the process proceeds to step S72. On the other hand, when the collision determination ECU 20 determines that the depression flag is in the off state, the collision determination ECU 20 advances the process to step S66.

  In step S66, the collision determination ECU 20 determines whether or not the accelerator opening gradient D is equal to or greater than the first gradient threshold Dth1. If the collision determination ECU 20 determines that the accelerator opening gradient D is equal to or greater than the first gradient threshold Dth1, the process proceeds to step S67. On the other hand, when the collision determination ECU 20 determines that the accelerator opening gradient D is less than the first gradient threshold Dth1, the process proceeds to step S7 in FIG.

  In step S67, the collision determination ECU 20 sets the stepping flag on. When the collision determination ECU 20 completes the process of step S67, the process proceeds to step S68.

  In step S68, the collision determination ECU 20 increments the stepping counter N. The depression counter N is a value indicating the number of times the driver has depressed the accelerator pedal. The initial value of the stepping counter N is preset to, for example, zero. The collision determination ECU 20 adds a predetermined constant (for example, 1) to the stepping counter N, and stores the value after the addition in the storage device. When the collision determination ECU 20 completes the process of step S68, the process proceeds to step S69.

  According to the processing from step S65 to step S68, when the stepping flag is switched from the off state to the on state, that is, every time the driver steps on the accelerator pedal, the value of the stepping counter N increases.

  In step S69, the collision determination ECU 20 determines whether or not the stepping counter N is greater than or equal to the counter threshold value Nth. The counter threshold Nth is a threshold for determining whether or not the driver has performed a continuous stepping operation. The counter threshold value Nt is a predetermined constant (for example, 2). When the collision determination ECU 20 determines that the step-in counter N is equal to or greater than the counter threshold value Nth, the collision determination ECU 20 advances the process to step S70. On the other hand, when the collision determination ECU 20 determines that the depression counter N is less than the counter threshold value Nth, the collision determination ECU 20 advances the process to step S71.

  In step S70, the collision determination ECU 20 sets the continuous stepping flag on. The continuous depressing flag is flag data indicating that the driver has performed a continuous depressing operation when the flag is on, and indicates that the driver has performed the continuous depressing operation when the flag is off. . It is assumed that the continuous depression flag is set to an off state in the initial state. When the collision determination ECU 20 completes the process of step S70, the process proceeds to step S7 of FIG.

  In step S71, the collision determination ECU 20 sets the continuous stepping flag to an off state. When the collision determination ECU 20 completes the process of step S71, the collision determination ECU 20 advances the process to step S7 of FIG.

  In step S72, the collision determination ECU 20 determines whether or not the accelerator opening gradient D is equal to or less than the second gradient threshold Dth2. When the collision determination ECU 20 determines that the accelerator opening gradient D is the second gradient threshold value Dth2, the process proceeds to step S73. On the other hand, when the collision determination ECU 20 determines that the accelerator opening gradient D is larger than the second gradient threshold Dth2, the process proceeds to step S7 in FIG.

  In step S73, the collision determination ECU 20 sets the stepping flag to the off state. When the collision determination ECU 20 completes the process of step S73, the process proceeds to step S7 of FIG.

  In step S7, the collision determination ECU 20 determines whether or not the continuous stepping flag is on. If the collision determination ECU 20 determines that the continuous stepping flag is on, the process proceeds to step S8 and stops automatic braking. On the other hand, when the collision determination ECU 20 determines that the continuous stepping flag is off, the process proceeds to step S9.

  In step S8, the collision determination ECU 20 transmits an instruction signal for stopping automatic braking to the brake control ECU 30. In step S8, the collision determination ECU 20 stops the automatic braking and initializes the above-described continuous stepping flag, continuous stepping flag, stepping flag, timer value T, and stepping counter N. When the collision determination ECU 20 completes the process of step S8, the process proceeds to step S9.

  In step S9, the collision determination ECU 20 determines whether or not the automatic braking system is set to the off state by the user. When the collision determination ECU 20 determines that the automatic braking system is set to the off state, the collision determination ECU 20 ends the process of FIG. On the other hand, when the collision determination ECU 20 determines that the automatic braking system is not set to the off state, the collision determination ECU 20 returns the process to step S1 and repeatedly executes the processes of the above steps.

  Next, how the automatic braking is released by the vehicle braking control device 1 will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram illustrating a state in which the vehicle brake control device 1 detects the driver's continuous stepping operation and releases the automatic braking. FIG. 7 is a diagram illustrating a state in which the vehicle braking control device 1 detects the driver's continuous stepping operation and releases the automatic braking.

  In the graph shown in FIG. 6A, the vertical axis represents the accelerator opening K, and the horizontal axis represents time t. In addition, in (a) of FIG. 6, a dotted line shows the opening degree threshold value Kth. In the graph shown in FIG. 6B, the vertical axis represents the braking force of automatic braking generated in the host vehicle (hereinafter referred to as automatic braking force P), and the horizontal axis represents time t. As shown in FIG. 6A, it is assumed that the driver of the host vehicle starts the depression operation of the accelerator pedal from time t1 and maintains a substantially constant amount of depression from time t2.

  First, as shown in FIG. 6B, automatic braking is started at time t1 (step S3). When automatic braking is started, the speed of the host vehicle gradually decreases as shown in FIG. 6A, so that the value of the opening threshold value Kth gradually increases. Thereafter, as shown in FIG. 6A, at the time t2, the value of the accelerator opening K exceeds the opening threshold Kth (Yes in step S46). When the time corresponding to the timer threshold Tth has elapsed from time t2 while the value of the accelerator opening K exceeds the opening threshold Kth (Yes in step S49), the continuous stepping flag is set to the on state (step S50). ). Then, at time t3 when the continuation stepping flag is turned on (Yes in step S5), automatic braking is stopped (step S8), and the value of automatic braking force P is zero as shown in FIG. 6B. Become.

  As described above, according to the vehicle brake control device 1 according to the embodiment of the present invention, when the driver performs the continuous depressing operation to continuously depress the accelerator pedal, the execution of the automatic braking can be stopped.

  In the graph shown in FIG. 7A, the vertical axis represents the accelerator opening K, and the horizontal axis represents time t. In the graph shown in FIG. 7B, the vertical axis represents the accelerator opening gradient D, and the horizontal axis represents time t. In FIG. 7B, the alternate long and short dash line indicates the first gradient threshold Dth1, and the alternate long and two short dashes line indicates the second gradient threshold Dth2. In the graph shown in FIG. 7C, the vertical axis represents the automatic braking force P, and the horizontal axis represents time t. As shown to (a) of FIG. 7, the driver of the own vehicle starts the depression operation of an accelerator pedal from the time t5, and loosens the depression at the time t6. After that, it is assumed that the driver performs the stepping operation again at time t7.

  As shown in FIG. 7C, first, the vehicle braking control device 1 starts automatic braking at time t4 (step S3). Thereafter, as shown in FIG. 7B, when the value of the accelerator opening gradient D exceeds the first gradient threshold value Dth1 at time t5 (Yes in step S66), the depression flag is set to the on state (step In step S67, the value of the step-in counter N becomes 1 (step S68). At this time, since the value of the stepping counter N is 2 or less of the threshold value Nth (No in step S69), the process is repeated while the continuous stepping flag remains off (step S71). Thereafter, when the value of the accelerator opening gradient D falls below the second gradient threshold value Dth2 at time t6 (Yes in step S72), the stepping flag is temporarily set to an off state (step S73). Further, at time t7, when the value of the accelerator opening gradient D again exceeds the first gradient threshold Dth1 (Yes in step S66), the depression flag is set to the on state again (step S67), and the value of the depression counter N is set. Becomes 2 (step S68). At this time, since the value of the stepping counter N exceeds the threshold value Nth (Yes in step S69), the continuous stepping flag is set to the on state (step S71). When the continuous stepping flag is set to the on state (Yes in step S7), the automatic braking is stopped (step S8), and the value of the automatic braking force P becomes zero as shown in FIG. 7 (c).

  As described above, according to the vehicle brake control device 1 according to the embodiment of the present invention, the execution of automatic braking can be stopped when the driver performs a continuous depressing operation that continuously depresses the accelerator pedal.

  As described above, according to the vehicle control device 1 according to the embodiment of the present invention, when the driver performs the continuous stepping operation and the continuous stepping operation, that is, with the intention of accelerating the host vehicle, When operated, execution of automatic braking can be stopped.

  In the above-described embodiment, an example in which the collision determination ECU 20 calculates the opening threshold value Kth and the first gradient threshold value Dth1 based on the travel speed Vs has been described. However, the collision determination ECU 20 includes the opening threshold value Kth and the first gradient threshold value Dth1. The threshold value Dth1 may be calculated based on other parameters. For example, the collision determination ECU 20 may calculate the opening degree threshold value Kth and the first gradient threshold value Dth1 based on the collision determination time TTC. More specifically, the collision determination ECU 20 may calculate the opening threshold value Kth and the first gradient threshold value Dth1 so that the collision determination time TTC is shorter. The collision determination ECU 20 may calculate the opening degree threshold value Kth and the first gradient threshold value Dth1 based on the relative speed Vr with the obstacle. More specifically, the collision determination ECU 20 calculates the opening threshold value Kth and the first gradient threshold value Dth1, respectively, as the relative speed Vr between the host vehicle and the obstacle increases in the direction approaching the host vehicle. It doesn't matter. If the opening degree threshold value Kth and the first gradient threshold value Dth1 are calculated in this way, it is difficult to release the automatic braking when the possibility of a collision is relatively high, and the automatic braking is prevented from being released accidentally. Can do.

  Further, the collision determination ECU 20 counts the elapsed time from the start of automatic braking, that is, the length of time during which automatic braking is executed, and calculates the opening degree threshold value Kth and the first gradient threshold value Dth1 based on the time. It doesn't matter. It can be considered that the degree of request for releasing the automatic braking by the driver differs immediately after the start of the automatic braking and after a certain time has elapsed after the start. Therefore, by calculating the gradient threshold according to the length of the braking time, it is possible to easily release (or make it difficult to release) the automatic braking according to the driver's request. In order to make it easy to release the automatic braking, the collision determination ECU 20 calculates the opening threshold value Kth and the first gradient threshold value Dth1 to be smaller as the execution time of the automatic braking is longer, and makes it difficult to release the automatic braking. The collision determination ECU 20 calculates the values of the opening threshold value Kth and the first gradient threshold value Dth1 larger as the execution time of the automatic braking is longer.

  The collision determination ECU 20 may store values of the opening threshold value Kth, the first gradient threshold value Dth1, and the second gradient threshold value Dth2 as constants in advance. In this case, the processing time can be shortened by omitting the process of calculating the threshold.

  In addition, the execution order of the process of each step which the said collision determination ECU20 performs is an example, for example, after performing the process of step S6 and step S7 sequentially, the collision determination ECU20 performs the process of step S4 and step S5 sequentially. May be executed. Further, the collision determination ECU 20 may execute the process of step S63 described above immediately before executing step S72 after determining that the stepping flag is on (Yes in step S65).

  The vehicle brake control device according to the present invention is useful as a vehicle brake control device capable of accurately releasing automatic braking according to the driver's intention.

DESCRIPTION OF SYMBOLS 1 Vehicle braking control apparatus 11 Radar apparatus 12 Accelerator apparatus 13 Vehicle speed sensor 14 Acceleration sensor 20 Collision judgment ECU
30 Brake control ECU

Claims (10)

A vehicle braking control device that automatically brakes the host vehicle according to the risk of collision between the host vehicle and an obstacle,
Collision determination means for determining whether or not there is a high risk of collision between the host vehicle and the obstacle;
Automatic braking means for automatically generating a braking force by controlling the brake device of the own vehicle when the collision determination means determines that the risk of collision between the own vehicle and an obstacle is high;
Automatic braking release means for stopping generation of the automatic braking force by the automatic braking means based on the frequency of operation of the accelerator pedal of the own vehicle by the driver of the own vehicle, Braking control device. The automatic braking release means includes continuous stepping operation determination means for determining whether or not a driver of the own vehicle has performed a continuous stepping operation of continuously depressing an accelerator pedal of the own vehicle at a high frequency,
The vehicle control device includes:
Accelerator opening detection means for detecting the accelerator opening of the host vehicle;
An opening degree gradient calculating means for calculating an amount of change of the accelerator opening per predetermined time as an accelerator opening degree gradient;
The said continuous stepping operation determination means determines whether the said continuous stepping operation was performed based on the magnitude relationship between the said accelerator opening gradient and a predetermined gradient threshold value. Brake control device for vehicles. The gradient threshold includes a first opening gradient threshold and a second opening gradient threshold smaller than the first opening gradient threshold,
The continuous depressing operation determination means determines that the driver has performed an operation of depressing the accelerator pedal when the accelerator opening gradient exceeds a first gradient threshold value, and the accelerator opening gradient is the second gradient. When it is determined that the driver has performed an operation to loosen the depression of the accelerator pedal when the value is below the threshold, and an operation to depress the accelerator pedal and an operation to loosen the depression of the accelerator pedal are alternately performed a predetermined number of times or more The vehicle brake control device according to claim 2, wherein it is determined that the continuous stepping operation is performed. Own vehicle speed detecting means for detecting the running speed of the own vehicle;
The vehicular braking control apparatus according to any one of claims 2 to 3, further comprising a gradient threshold value calculation unit that calculates the gradient threshold value based on a traveling speed of the host vehicle. A relative speed calculating means for detecting a relative speed between the host vehicle and the obstacle;
The vehicular braking control apparatus according to any one of claims 2 to 3, further comprising a gradient threshold value calculating unit that calculates the gradient threshold value based on the relative speed. A predicted collision time calculating means for calculating, as a predicted collision time, a time required for the host vehicle and a vehicle following the host vehicle to collide;
The vehicular braking control apparatus according to any one of claims 2 to 3, further comprising a gradient threshold value calculation unit that calculates the gradient threshold value based on the predicted collision time. Automatic braking time calculating means for calculating an elapsed time from the time when the automatic braking means starts generation of automatic braking force as braking time;
The vehicle brake control device according to any one of claims 2 to 3, further comprising gradient threshold value calculation means for calculating the gradient threshold value based on a length of the braking time.   The automatic braking release means includes a continuous stepping operation determination means for determining whether or not a driver of the host vehicle has performed a continuous stepping operation for maintaining a state where the accelerator pedal is depressed. The vehicle brake control device according to any one of 7. An accelerator opening detecting means for detecting the accelerator opening of the host vehicle;
The accelerator operation determination means determines that the continuous stepping operation is performed when a state in which the accelerator opening of the host vehicle exceeds a predetermined opening threshold value continues for a predetermined time or longer. The vehicle brake control device according to claim 8. A vehicle that detects at least one of a traveling speed of the host vehicle, a relative speed of the obstacle with respect to the host vehicle, and a predicted collision time predicted to be required until the host vehicle and the obstacle collide. State quantity detection means;
The opening degree threshold value calculation means for calculating the opening degree threshold value based on at least one of the traveling speed, the relative speed, and the predicted collision time. Vehicle brake control device.

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