JP6417877B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake control device that performs automatic brake control for automatically applying a brake to avoid a collision with an obstacle.

  Conventionally, a vehicle brake that detects an obstacle in the traveling direction of the host vehicle while traveling and executes automatic brake control to automatically apply a brake to avoid a collision between the obstacle and the host vehicle. A control device has been proposed (see, for example, Patent Document 1).

  In this vehicle brake control device, the distance from the host vehicle to the obstacle is calculated, and a warning is given to the driver when the distance reaches the first threshold. This causes the driver to perform a driving operation for avoiding the obstacle appropriately. Further, when the driver does not perform an appropriate driving operation and the distance from the host vehicle to the obstacle becomes a second threshold value that is smaller than the first threshold value, automatic braking is applied.

  Specifically, the motor is driven at the same time as the distance from the host vehicle to the obstacle reaches the second threshold value, and the brake fluid is sucked and discharged by the pump. Further, a differential pressure control valve provided between a master cylinder (hereinafter referred to as M / C) and a wheel cylinder (hereinafter referred to as W / C) is in a differential pressure state. Thereby, a desired W / C pressure can be generated based on the differential pressure generated by the differential pressure control valve, and automatic braking can be applied. In this way, avoidance of collision between the host vehicle and the obstacle is supported.

Special table 2008-525254 gazette

  In recent years, the demand for safety has increased, and the establishment of automatic braking has been demanded from an earlier stage, that is, from a high vehicle speed.

  However, in the above-described conventional vehicle brake control device, the motor is driven after the distance from the host vehicle to the obstacle reaches the second threshold, and the brake fluid is sucked and discharged by the pump. For this reason, there is a problem that it takes time until the desired rotational speed is reached after the motor rotation rises, and it takes time to generate the desired W / C pressure.

  On the other hand, the motor drive is started when the distance from the host vehicle to the obstacle reaches the first threshold, and the W / C pressure is generated quickly when the distance reaches the second threshold. It can also be considered. However, if the motor is continuously driven until the distance from the host vehicle to the obstacle reaches the second threshold value from the first threshold value, the motor driving time becomes longer and the power consumption increases. In addition, even if the differential pressure control valve is not in the differential pressure state, W / C pressure may be generated due to the throttle inside the differential pressure control valve, giving the driver a feeling of brake dragging. There is also.

  In view of the above points, the present invention provides a vehicle brake capable of generating a braking force at an earlier timing and preventing a motor driving time from becoming too long when it is necessary to apply an automatic brake. An object is to provide a control device.

  In order to achieve the above object, the invention according to claim 1 predicts that the host vehicle collides with an obstacle, and the predicted collision time, which is the time until the collision occurs when predicted to collide, is the first time. The first collision prediction means (S110) for determining whether or not the vehicle has reached the vehicle and the collision prediction means determines that the collision prediction time has reached the first time, the vehicle collides with an obstacle to the driver. A notifying means (S115) for notifying that there is a possibility of the occurrence of the collision, and calculating an avoidance limit time which is a minimum time required for avoiding a collision between the host vehicle and the obstacle by applying an automatic brake, and the avoidance limit time Is calculated as a second time shorter than the first time (S120), and an arrival time for calculating a motor rotation arrival time, which is a time taken from the start of rotation of the motor (60) to a steady state. Calculation means ( 130) and when the predicted collision time reaches the time obtained by adding the motor rotation arrival time to the second time, the rotation instruction means (S135) for instructing the start of rotation of the motor, and the predicted collision time reaches the second time. And brake starting means (S145 to S155) for applying an automatic brake.

  In this way, when the postponement collision time reaches the first time, the driver is informed that there is a possibility of a collision. This can prompt the driver to perform an operation for avoiding a collision. Even if the driver does not perform an appropriate operation to avoid a collision, when the collision postponement time reaches the second time, it is possible to avoid collision between the host vehicle and the obstacle by applying an automatic brake. Yes.

  When performing such avoidance, the motor drive starts before the collision grace time reaches the second time, and the start of the motor drive is not the timing when the collision grace time becomes the first time. It is determined by calculating backward from the timing of 2 hours. Therefore, it is possible to generate the braking force at an earlier timing while preventing the motor driving time from becoming too long.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a hydraulic circuit diagram showing a basic configuration of a vehicle brake device 1 according to a first embodiment of the present invention. 3 is a block diagram showing the input / output relationship with respect to a brake ECU 70. It is a flowchart of the automatic brake control which brake ECU70 performs. 6 is a time chart showing a change with time in the rotation state of the motor 60; It is the figure which showed the relationship between the motor torque corresponding to the voltage of the power supply 61, and motor rotation speed. It is the time chart which showed the mode of the motor rotation speed at the time of 1st Embodiment and the conventional automatic brake control, and the change of W / C pressure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments shown in the drawings will be described below. A brake system to which a vehicle brake control device according to an embodiment of the present invention is applied will be described. FIG. 1 is a hydraulic circuit diagram showing a basic configuration of a brake system 1 according to the present embodiment. Here, a vehicle constituting a hydraulic circuit for front and rear pipes will be described as an example, but a vehicle such as an X pipe may be used.

  As shown in FIG. 1, a brake pedal 11 as a brake operation member operated by a driver is connected via a booster 12 to an M / C 13 serving as a brake fluid pressure generation source. When the brake pedal 11 is stepped on, the stepping force is boosted by the booster 12, and the master pistons 13a and 13b disposed in the M / C 13 are pressed based on the stepping force. As a result, the same M / C pressure is generated in the primary chamber 13c and the secondary chamber 13d defined by the master pistons 13a and 13b. The M / C pressure is transmitted to each of the W / Cs 14, 15, 34, and 35 through the brake fluid pressure control actuator 50. The M / C 13 is provided with a master reservoir 13e having passages communicating with the primary chamber 13c and the secondary chamber 13d.

  The brake fluid pressure control actuator 50 includes a first piping system 50a and a second piping system 50b, and is integrated by assembling various parts to a block made of aluminum or the like (not shown) that forms the brake piping. Has been. The first piping system 50a is a rear system that controls the brake fluid pressure applied to the left rear wheel RL and the right rear wheel RR, and the second piping system 50b is the brake fluid pressure that is applied to the left front wheel FL and the right front wheel FR. It is assumed to be a front system.

  In addition, since the basic composition of each system | strain 50a, 50b is the same, below, the 1st piping system 50a is demonstrated and description is abbreviate | omitted about the 2nd piping system 50b.

  The first piping system 50a transmits the M / C pressure described above to the W / C 14 provided in the left rear wheel RL and the W / C 15 provided in the right rear wheel RR, and generates a W / C pressure. A conduit A is provided.

  By controlling the pipeline A to a communication state and a differential pressure state, the pipeline A has a first pipeline on the M / C 13 side on the upstream side and a second pipe on the W / C 14 and 15 side on the downstream side. A first differential pressure control valve 16 that controls the differential pressure with the passage is provided. The first differential pressure control valve 16 is in a communicating state during normal braking in which the driver operates the brake pedal 11 (when automatic brake control such as collision avoidance or vehicle motion control such as skid prevention control is not executed). The valve position is adjusted so that When a current is passed through the solenoid coil provided in the first differential pressure control valve 16, the valve position of the first differential pressure control valve 16 is adjusted so that the larger the flowed current value is, the larger the differential pressure state is. Is done.

  When the first differential pressure control valve 16 is in the differential pressure state, only when the brake fluid pressure on the W / C 14, 15 side is higher than the M / C pressure by a predetermined level or more, the M / Brake fluid flow to the C13 side is allowed. For this reason, the W / C 14, 15 side is always maintained so as not to be higher than the predetermined pressure by the M / C 13 side. Further, a check valve 16 a is provided in parallel with the first differential pressure control valve 16.

  The pipeline A branches into two pipelines A1 and A2 on the W / C 14 and 15 side downstream of the first differential pressure control valve 16. The pipeline A1 is provided with a first pressure increase control valve 17 that controls the increase of the brake fluid pressure to the W / C 14, and the pipeline A2 is a first pressure that controls the increase of the brake fluid pressure to the W / C 15. A two pressure increase control valve 18 is provided.

  The first and second pressure-increasing control valves 17 and 18 are normally open type two-position solenoid valves that can control the communication / blocking state. Specifically, the first and second pressure increase control valves 17 and 18 are set when the control current to the solenoid coils provided in the first and second pressure increase control valves 17 and 18 is zero (during non-energization). ) Is controlled to the communication state. Further, the first and second pressure increase control valves 17 and 18 are controlled to be cut off when a control current is passed through the solenoid coil (when energized).

  The first pressure reduction control valve 21 is connected to the first and second pressure increase control valves 17 and 18 in the pipe A and the pipe B serving as a pressure reduction reservoir connecting the pressure regulating reservoir 20 between the W / Cs 14 and 15. And a second pressure reduction control valve 22 are provided. These first and second pressure-reducing control valves 21 and 22 are normally closed two-position solenoid valves that can control the communication / blocking state. Specifically, the first and second pressure reduction control valves 21 and 22 are when the control current to the solenoid coils provided in the first and second pressure reduction control valves 21 and 22 is zero (when no power is supplied). Is controlled to the shut-off state. The first and second pressure reduction control valves 21 and 22 are controlled to be in communication when a control current is passed through the solenoid coil (when energized).

  A conduit C serving as a reflux conduit is disposed between the pressure regulating reservoir 20 and a conduit A serving as a main conduit. The pipe C is provided with a self-priming pump 19 driven by a motor 60 that sucks and discharges brake fluid from the pressure regulating reservoir 20 toward the M / C 13 side or the W / C 14, 15 side. The motor 60 is driven based on power supply from a power source 61 such as a battery, and is driven when the switch 62 is turned on. The motor 62 can be controlled by controlling the frequency of the switch 62 such as PWM control.

  A conduit D serving as an auxiliary conduit is provided between the pressure regulating reservoir 20 and the M / C 13. The brake fluid is sucked from the M / C 13 by the pump 19 through this pipeline D and discharged to the pipeline A, so that the brake fluid is supplied to the W / C 14, 15 side during vehicle motion control. The W / C pressure of the wheel is increased.

  In addition, although the 1st piping system 50a was demonstrated here, the 2nd piping system 50b is also the same structure, The 2nd piping system 50b is also provided with the structure similar to each structure with which the 1st piping system 50a was equipped. Yes. Specifically, the second differential pressure control valve 36 and the check valve 36a corresponding to the first differential pressure control valve 16 and the check valve 16a, the third corresponding to the first and second pressure increase control valves 17 and 18, respectively. The fourth pressure increase control valves 37 and 38 are provided. In addition, there are third and fourth decompression control valves 41 and 42 corresponding to the first and second decompression control valves 21 and 22, a pump 39 corresponding to the pump 19, and a pressure regulation reservoir 40 corresponding to the pressure regulation reservoir 20. Furthermore, there are pipelines E to H corresponding to the pipelines A to D. However, for the W / Cs 14, 15, 34, and 35 in which the systems 50a and 50b supply brake fluid, the second piping system 50b serving as the front system is larger than the first piping system 50a serving as the rear system. There may be a difference in capacity. In the case of such a configuration, a larger braking force can be generated on the front side.

  The brake system 1 includes an electronic control device (hereinafter referred to as a brake ECU) 70 for brake control corresponding to a vehicle brake control device. The brake ECU 70 is constituted by a well-known microcomputer having a CPU, ROM, RAM, I / O, etc., and executes various calculations according to a program stored in the ROM, etc., and performs automatic brake control and various vehicle motion control. The brake control including is executed.

  For example, the brake ECU 70 inputs detection signals from various sensors, detects the relative position of the obstacle with respect to the host vehicle, the distance between the two, the speed of the host vehicle, and the direction of travel. It calculates the possibility of collision and the deceleration required to avoid the collision. Based on the calculation result, when a predetermined condition is satisfied, various components provided in the brake hydraulic pressure control actuator 50 are controlled to generate a braking force that provides a desired deceleration for the wheel to be controlled. Automatic brake control is executed. The brake ECU 70 also controls the motor rotation speed in the automatic brake control according to the voltage of the power supply 61 as necessary.

  Specifically, as shown in FIG. 2, the brake ECU 70 receives detection signals from the wheel speed sensors 71 to 74 provided for each wheel, the voltage sensor 75 for detecting the voltage of the power supply 61, and the steering angle sensor 76. Has been. Based on these detection signals, the brake ECU 70 detects the speed and traveling direction of the host vehicle and the voltage of the power supply 61. The brake ECU 70 also receives obstacle information such as a detection signal of the obstacle sensor and image data of the front monitoring camera from an obstacle detection unit 77 including an obstacle sensor and a front monitoring camera. Based on the obstacle information, the brake ECU 70 recognizes the obstacle and obtains the relative position and relative speed of the obstacle with respect to the host vehicle, the distance between the two, and the direction of the obstacle. Also, the brake ECU 70 avoids the possibility of collision with the obstacle and the collision based on the speed and traveling direction of the own vehicle, the relative position and relative speed of the obstacle with respect to the own vehicle, and the distance between the two. It calculates the necessary deceleration and the minimum time to avoid.

  When executing various brake fluid pressure controls such as automatic brake control and various vehicle motion controls, the brake ECU 70 applies the brake fluid pressure control actuator 50 to the brake fluid pressure control actuator 50 based on the request from the executed brake fluid pressure control. Control each part provided. That is, by driving various control valves or by driving the motor 60, the pumps 19 and 39 are operated, and the suction and discharge operations of the brake fluid by the pumps 19 and 39 are performed. Thereby, for example, when the pumps 19 and 39 are operated while the first and second differential pressure control valves 16 and 36 are in a differential pressure state, the differential pressure generated by the first and second differential pressure control valves 16 and 36 It is possible to generate a W / C pressure corresponding to the pressure. Based on this, it is possible to generate a desired braking force according to a request from the brake fluid pressure control.

  In automatic brake control, a collision prediction announcement is made to the driver before actual automatic braking is applied. For this reason, the brake ECU 70 outputs an announcement command signal to the alarm unit 78 that performs voice guidance and display guidance on the display, and the alarm unit 78 makes a collision prediction announcement.

  As described above, the brake system 1 according to the present embodiment is configured. Then, an example of operation | movement of the brake system 1 comprised in this way is demonstrated. In the brake system 11 of this embodiment, in addition to automatic brake control for avoiding a collision between the host vehicle and an obstacle, vehicle stabilization such as normal braking operation based on the driver's brake pedal depression and skid prevention control is performed. Various vehicle motion control for can be executed. However, the present embodiment is characterized by automatic brake control, and other vehicle motion control is the same as the conventional one. Therefore, only the automatic brake control will be described here.

  FIG. 3 shows a flowchart of the automatic brake control executed by the brake ECU 70, and the operation of the automatic brake control will be described with reference to this figure. Each process of the automatic brake control shown in FIG. 3 is executed at predetermined control cycles when, for example, the driver presses an execution switch for automatic brake control (not shown).

  First, in step 100, it is determined whether or not there is an obstacle that is an object to be avoided in the traveling direction of the host vehicle, that is, a person or an object. This determination is made based on detection signals from various sensors and obstacle information from the obstacle detection unit 77. For example, the traveling direction of the vehicle is detected from the steering angle obtained from the detection signal of the steering angle sensor 76 and the speed of the host vehicle obtained from the detection signals of the wheel speed sensors 71 to 74. For this reason, the presence or absence of an obstacle is determined from the obstacle information of the obstacle detection unit 77, and if an obstacle is present, whether the obstacle is present in the traveling direction is determined in the future. Judgment is made including whether the vehicle enters in the direction of travel.

  If an affirmative determination is made here, there is a possibility that the automatic brake may be applied. Therefore, the process proceeds to step 105. If a negative determination is made, it is not necessary to apply the automatic brake.

  In the following step 105, the relative position and relative speed of the obstacle with respect to the host vehicle, the distance between the two, and the direction of the obstacle are calculated by a well-known method. Then, the process proceeds to step 110, and a collision prediction is performed based on the calculation result of step 105. Specifically, it is determined whether or not the time taken from the present time until the own vehicle and the obstacle collide (hereinafter referred to as a collision postponement time) is equal to or shorter than a first time that is a first threshold value. The collision postponement time is calculated by a well-known method from the relative position and relative speed of the obstacle with respect to the host vehicle calculated in step 105 and the distance between the two and the direction of the obstacle.

  Here, the first time is set to a time during which the driver can avoid a collision between the host vehicle and the obstacle by performing an appropriate avoidance operation. The first time is at least the time from the start of driving the motor 60 until the motor rotation rises to the desired number of rotations, and the automatic braking is applied to avoid collision between the host vehicle and the obstacle. It is set to a time longer than the total time taken to complete the process.

  If an affirmative determination is made in step 110, the process proceeds to step 115, and an announcement command signal is output to the alarm unit 78 in order to make a collision prediction announcement. Based on this, the driver is made aware that there is a possibility that the host vehicle collides with an obstacle, and performs an appropriate operation for avoiding the collision with the obstacle.

  Thereafter, the process proceeds to step 120, and the avoidance limit time is calculated. The avoidance limit time means the minimum time required for applying the automatic brake to avoid the collision between the vehicle and the obstacle. This avoidance limit time is used as a second time corresponding to the second threshold, and is shorter than the first time described above.

  In step 125, the voltage of the power supply 61 of the motor 60 is measured from the detection signal of the voltage sensor 75. In step 130, the motor rotation arrival time is calculated based on the measured voltage of the power supply 61.

  The motor rotation arrival time is a desired number of rotations (a predetermined number of rotations with respect to the steady rotation number) after the motor 60 starts to rotate, and the suction and discharge operations by the pumps 19 and 39 are steady from the transient state at the initial rotation. The time it takes to change to the state. That is, as shown in FIG. 4, the motor rotation speed gradually increases from the rise of rotation, and becomes a steady rotation speed of constant rotation over a predetermined time. It is assumed that the W / C pressure can be increased with good responsiveness if the motor rotational speed is a predetermined ratio with respect to the steady rotational speed. Accordingly, the time required for the rotation speed to reach a predetermined ratio, for example, 90%, with respect to the steady rotation speed is set as the motor rotation arrival time.

  Further, the torque required to rotate the pumps 19 and 39 according to the voltage of the power supply 61 (hereinafter referred to as motor required torque) is different. Specifically, as shown in FIG. 5, the higher the voltage of the power supply 61, the higher the target rotational speed necessary to obtain the motor required torque. Therefore, based on the map shown in FIG. 5 and the like, the target rotational speed of the motor 60 corresponding to the necessary motor torque is obtained, and this target rotational speed is set as the steady rotational speed. Then, when the frequency of the switch 62 is controlled to set the motor rotation speed to the steady rotation speed (target rotation speed), the time required to reach a predetermined ratio with respect to the steady rotation speed is obtained as the motor rotation arrival time. If the first and second differential pressure control valves 16 and 36 are brought into the differential pressure state after the elapsed time from the start of motor rotation reaches the rotation arrival time, the W / C pressure can be generated with good responsiveness.

  Thereafter, the process proceeds to step 135, where it is determined whether or not it is time to give a motor rotation instruction. The timing for instructing the motor rotation is the timing obtained from the time obtained by adding the motor rotation arrival time to the second time described above. That is, in this step, it is determined whether or not the collision grace time is equal to or shorter than the time obtained by adding the motor rotation arrival time to the second time.

  If an affirmative determination is made in this step, the routine proceeds to step 140 where a motor rotation instruction is issued and the rotation of the motor 60 is started. Thereafter, the process proceeds to step 145, and collision prediction is performed again. Specifically, it is determined whether or not the collision postponement time is equal to or shorter than the second time based on the elapsed time from the timing when the affirmative determination is made in step 110, that is, the timing when the collision postponement time becomes the first time or less. To do. Further, it is determined whether or not the driver has performed an avoidance operation until this determination is affirmative. For example, when the obstacle is removed from the traveling direction of the host vehicle by the steering operation or the collision between the host vehicle and the obstacle is avoided by the brake operation, it is determined that the driver has performed the avoiding operation. The steering operation can be confirmed by the detection signal of the steering angle sensor 76, and the brake operation has been performed by providing an M / C sensor and inputting the detection signal of the M / C pressure sensor to the brake ECU 70. It can be confirmed with.

  Here, if the driver does not perform an operation for avoiding the collision postponement time reaches the second time, it is determined that the own vehicle can collide with an obstacle, and if the operation is performed, the own vehicle Is determined not to collide with an obstacle.

  If an affirmative determination is made in step 145, the process proceeds to step 150 to make an automatic brake start determination, and the process proceeds to step 155 to instruct the start of automatic brake so as to avoid the vehicle from colliding with an obstacle. To do. Thereby, the first and second differential pressure control valves 16 and 36 are controlled to the differential pressure state, and the W / C pressure is generated based on the pump drive. At this time, since the rotation of the motor 60 has already started and has reached the desired number of revolutions, the suction and discharge operations of the pumps 19 and 39 are also in a steady state, and the W / C pressure is generated with good responsiveness. It is done. Therefore, a desired braking force can be obtained immediately and a desired deceleration can be generated.

  Thereafter, in step 160, it is determined whether or not a collision has been avoided. For example, when it is determined that the host vehicle stops or the same process as in step 100 is performed and no obstacle is present from the traveling direction of the host vehicle, it is determined that the collision is avoided. Then, automatic braking is continued until an affirmative determination is made here, and when an affirmative determination is made, the process proceeds to step 165 to end the rotation of the motor 60 and the process is ended.

  On the other hand, if a negative determination is made in step 145, since the collision between the host vehicle and the obstacle has already been avoided by the driver's operation, an instruction to stop the driving of the motor 60 is issued and the process is terminated.

  In this way, automatic brake control is executed. FIG. 6 is a time chart comparing the change in the motor rotation speed and the change in the W / C pressure when the automatic brake control is executed as compared with the conventional case.

  As shown in this figure, it has been reported that there is a possibility of collision with the driver when the collision grace time reaches the first threshold, and then that time becomes the second threshold. The motor drive was started. For this reason, the W / C pressure does not increase unless the time from the start of motor driving until the motor rotation reaches the desired number of rotations after the collision postponement time reaches the second threshold. Therefore, it takes time until the desired braking force is generated.

  On the other hand, in the case of the present embodiment, conventionally, it is reported that there is a possibility of collision with the driver when the collision grace time reaches the first threshold (first time), and thereafter Is started before the second threshold value (second time) is reached. In other words, when the collision grace time reaches the second threshold, the motor 60 has a desired rotational speed. For this reason, the W / C pressure can be increased immediately after the collision postponement time reaches the second threshold. Therefore, the time until the desired braking force is generated can be shortened.

  The motor driving time is shortened by determining the start of motor driving by calculating backward from the time at which the collision grace time becomes the first threshold, not at the time at which the second threshold is reached. For this reason, power consumption can be reduced. Further, when the W / C pressure is generated due to the restriction in the first and second differential pressure control valves 16 and 36, the driver feels dragging the brake. It is also possible not to give a feeling of dragging.

  As described above, in the present embodiment, the collision prediction announcement is made to the driver when the collision grace time reaches the first time that is the first threshold value. This can prompt the driver to perform an operation for avoiding a collision. Even if the driver does not perform an appropriate operation to avoid a collision, if the collision postponement time reaches the second threshold, which is the second threshold, the vehicle and the obstacle collide by applying an automatic brake. To avoid that.

  And when performing such avoidance, starting the motor drive in advance before the collision grace time reaches the second time, the start of the motor drive is not the timing when the collision grace time becomes the first threshold, It is determined by calculating backward from the timing as the second threshold. Therefore, the motor drive time can be prevented from becoming too long, and power consumption can be reduced. It is also possible to prevent the driver from feeling dragged.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in the above embodiment, the driver has described the steering operation and the brake operation as examples of the operation for avoiding the collision between the host vehicle and the obstacle, but the collision between the host vehicle and the obstacle is actually performed. The motor 60 may be stopped by determining whether or not it has been avoided. Specifically, when the host vehicle stops before the collision postponement time reaches the second time, or the possibility of collision between the host vehicle and the obstacle is measured again as in steps 100 and 105 of FIG. If the obstacle is removed from the traveling direction of the host vehicle, the motor 60 may be stopped.

  Further, it is not always necessary to stop the motor 60 when the driver performs an appropriate operation. However, it is preferable to stop the motor 60 in order to reduce power consumption.

  The steps shown in each figure correspond to means for executing various processes. That is, the part that executes the process of step 110 executes the first collision prediction means, the part that executes the process of step 115 performs the notification means, the part that executes the process of step 120 executes the second time calculation means, and executes the process of step 125 This portion corresponds to the voltage measuring means. Further, the part that executes the process of step 130 is the arrival time calculating means, the part that executes the process of step 135 is the rotation instruction means, the part that executes the processes of steps 145 to 155 is the brake start means, and executes the process of step 170 The part to perform corresponds to the stop instruction means. Furthermore, the part which performs the process of step 145 is corresponded also to a 2nd collision prediction means.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle brake device, 19, 39 ... Pump, 60 ... Motor, 61 ... Power supply, 62 ... Switch, 70 ... Brake ECU, 71-74 ... Wheel speed sensor, 75 ... Voltage sensor, 76 ... Steering angle sensor, 77 ... Obstacle detection unit

Claims (3)

The pump (19, 39) provided in the hydraulic circuit is operated by driving the motor (60), and the brake fluid is sucked and discharged by the pump, and the master cylinder (13) and the wheel cylinder (14, 15, 34, 35), a vehicle brake control device for automatically applying a brake by generating a wheel cylinder pressure by controlling a differential pressure control valve (16, 36) provided between the pressure control valve (16, 36) and a differential pressure state. ,
First collision prediction means for predicting that the host vehicle collides with an obstacle, and for determining whether or not the collision prediction time, which is the time until the collision occurs when the vehicle is predicted to collide, has reached the first time (S110). When,
When the collision prediction means determines that the predicted collision time has reached the first time, the notification means (S115) notifies the driver that the host vehicle may collide with the obstacle. )When,
An avoidance limit time, which is a minimum time required to avoid a collision between the host vehicle and the obstacle by applying the automatic brake, is calculated, and the avoidance limit time is set as a second time shorter than the first time. Second time calculation time (S120) to be
An arrival time calculation means (S130) for calculating a motor rotation arrival time which is a time taken from the start of rotation of the motor to a steady state;
When the predicted collision time reaches the time obtained by adding the motor rotation arrival time to the second time, rotation instruction means (S135) for instructing the start of rotation of the motor;
A vehicle brake control device comprising: brake start means (S145 to S155) for applying the automatic brake when the predicted collision time reaches the second time. Second collision prediction means (S145) for predicting whether or not the own vehicle will collide with the obstacle when the predicted collision time reaches the second time;
By the second collision prediction means, when the vehicle is determined not to collision with the obstacle, without applying the automatic brake at the braking start means, stop instruction to the rotation stop of the motor The vehicle brake control device according to claim 1, further comprising means (S170).
Voltage measuring means (S125) for measuring the voltage of the power source (61) for driving the motor;
The vehicle brake control device according to claim 1, wherein the arrival time calculation unit calculates the motor rotation arrival time based on the voltage of the power source measured by the voltage measurement unit.

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