JP6097355B2 - Braking device for vehicle - Google Patents

Description

  The present invention relates to a vehicle braking device for braking a vehicle.

  Patent Document 1 discloses an example of a vehicle braking device for braking a vehicle. The vehicle braking apparatus according to Patent Document 1 calculates a judgment distance or a target deceleration based on the own vehicle speed and the inter-vehicle distance, and requires a brake preload when the inter-vehicle distance is equal to or less than the judgment distance or the target deceleration exceeds a set value. When the accelerator pedal is released, the brake preload is set according to the vehicle speed, the accelerator return speed, etc., and the brake control is performed to generate the brake pressure according to the set brake preload.

  According to the vehicle brake device according to Patent Literature 1, the brake preload generated prior to the driver's braking operation can be set to an optimum value according to the driving situation so as not to give the driver a sense of incongruity.

JP 2000-309257 A

  By the way, in the vehicle braking device according to Patent Document 1, the vehicle encounters a collision accident even though the braking control for generating the braking force for reducing the collision damage of the vehicle is performed before the collision. Is not assumed. Therefore, in such a case, there is a possibility that accurate braking control cannot be performed, for example, braking control is stopped due to the influence of a collision.

  The present invention has been made in view of the above-described circumstances, and the vehicle has been subjected to a collision accident even though the braking control for generating the braking force for reducing the collision damage of the vehicle is performed before the collision. An object of the present invention is to provide a vehicular braking device that can accurately perform the braking control of the host vehicle even if it is encountered.

In order to achieve the above object, the invention according to (1) includes a braking force generation unit that generates a braking force for braking the host vehicle, and an information acquisition unit that acquires information on the possibility of collision of the host vehicle. A collision determination unit that determines the presence or absence of a collision of the host vehicle using a collision determination threshold, and when the information acquisition unit acquires information that there is a possibility of collision of the host vehicle, While performing a pre-collision braking control for causing the braking force generation unit to generate a pre-collision braking force to reduce the braking force, the post-collision braking force is set to A braking control unit that performs post-collision braking control to be generated by the braking force generation unit.
The collision determination unit mainly uses a lower value as the collision determination threshold after the pre-collision braking control is performed than the collision determination threshold when the pre-collision braking control is not performed. Features.

  In the invention according to (1), information indicating that there is a possibility of collision of the own vehicle is acquired, and the braking control for generating the pre-collision braking force for reducing the collision damage of the own vehicle is performed before the collision. Nevertheless, it is assumed that the vehicle encounters a collision accident. In this case, if the braking control that generates the pre-collision braking force is performed before the collision, the speed of the own vehicle may indicate that there is a possibility of collision of the own vehicle when the own vehicle actually encounters a collision accident. The speed is reduced compared to the speed at the time when the information was acquired. Therefore, the deceleration that occurs in the host vehicle when the host vehicle actually encounters a collision accident is reduced as compared with the case where the braking control that generates the pre-collision braking force is not performed before the collision. As a result, although the own vehicle actually encounters a collision accident, the collision determination unit makes an erroneous determination that the own vehicle is not colliding, and braking control that generates a braking force after the collision is performed. There is concern that it will not be done.

  Therefore, in the invention according to (1), the collision determination unit uses the collision when the pre-collision braking control is not performed by the braking control unit as the collision determination threshold value after the pre-collision braking control is performed by the braking control unit. A configuration using a value lower than the determination threshold is adopted.

  According to the invention according to (1), even when the host vehicle encounters a collision accident even though the braking control for generating the pre-collision braking force for reducing the collision damage of the host vehicle is performed. Thus, the braking control of the host vehicle can be performed accurately.

  The invention according to (2) is the vehicle braking apparatus according to the invention according to (1), wherein the braking control unit determines that the collision of the host vehicle is made by the collision determining unit. In addition, after-collision braking control is performed to cause the braking force generator to generate the post-collision braking force that is set to be larger than the pre-collision braking force.

  According to the invention according to (2), the braking control unit determines the post-collision braking force that is set larger than the pre-collision braking force when the collision determination unit determines that the host vehicle has a collision. Since the post-collision braking control to be generated by the braking force generator is performed, an effect of shortening the braking distance after the collision of the host vehicle can be expected as compared with the case of performing the braking control that maintains the pre-collision braking force.

  The vehicular braking apparatus according to the present invention is a case where the host vehicle encounters a collision accident in spite of performing the brake control for generating the pre-collision braking force for reducing the collision damage of the host vehicle. However, the braking control of the host vehicle can be accurately performed.

It is a lineblock diagram showing the outline of the brake device for vehicles concerning the embodiment of the present invention. It is a block diagram showing the periphery structure of ESB-ECU, CDR-ECU, and VSA-ECU which a vehicle braking device has. It is a flowchart figure with which it uses for operation | movement description of the braking device for vehicles. It is explanatory drawing showing the braking characteristic used before the collision of the own vehicle, and the braking characteristic used after the collision of the own vehicle in comparison. It is explanatory drawing which compares and represents a reference | standard collision determination threshold value and the collision determination threshold value after braking control before a collision is performed.

Hereinafter, a vehicle braking device 10 according to an embodiment of the present invention will be described in detail with reference to the drawings.
In addition, in the figure shown below, the common referential mark shall be attached | subjected between the members which have a common function, or between the members which have a mutually corresponding function. Further, for convenience of explanation, the size and shape of the member may be schematically represented by being deformed or exaggerated.

[Outline of Braking Device 10 according to Embodiment of the Present Invention]
The vehicle braking device 10 according to the embodiment of the present invention includes a by-wire (By) that generates a braking force through an electrical system in addition to an existing braking system that generates a braking force through a hydraulic system. (Wire) brake system.

  As shown in FIG. 1, the vehicle braking device 10 includes a pseudo braking fluid pressure generation device 14, an electric servo brake device (ESB device) 16, a collision damage reduction device (CDR device) 17 (see FIG. 2), The vehicle behavior stabilization support device (VSA device) 18 and the like are configured. As shown in FIG. 1, the pseudo braking fluid pressure generator 14, the ESB device 16, and the VSA device 18 are connected to each other via piping tubes 22 a to 22 f through which brake fluid flows.

  The pseudo braking fluid pressure generator 14 converts the pedaling force input by the driver via the brake pedal 12 into a pseudo braking fluid pressure. As shown in FIG. 1, the pseudo braking fluid pressure generator 14 includes a master cylinder 34, normally open first and second master cut valves 60 a and 60 b, a pair of braking fluid pressure sensors Pm and Pp, and a stroke simulator 64. It is configured with.

  The master cylinder 34 generates a pseudo braking fluid pressure corresponding to the operation of the brake pedal 12 by converting the pedaling force of the driver input through the brake pedal 12 into a pseudo braking fluid pressure.

The first and second master cut valves 60a and 60b are provided so as to be interposed in the piping tubes 22a and 22d that connect the master cylinder 34 and the ESB device 16 in communication. As shown in FIG. 1, the first and second master cut valves 60 a and 60 b are subjected to excitation control (pipe tubes 22 a and 22 d are shut off) when the vehicle braking device 10 is normally operated. Thereby, the communication between the master cylinder 34 and the disc brake mechanisms 30a to 30d (including the wheel cylinders 32FR, 32RL, 32RR, and 32FL) for braking each of the four wheels is cut off, thereby the ESB device 16 The disc brake mechanisms 30a to 30d are actuated using the brake fluid pressure generated.
In the following description, the wheel cylinders 32FR, 32RL, 32RR, and 32FL are collectively referred to as the wheel cylinder 32.

  The pair of brake fluid pressure sensors Pm and Pp are provided so as to be interposed in the piping tubes 22a and 22d that connect the master cylinder 34 and the ESB device 16 in communication. The brake fluid pressure sensor Pm has a function of detecting the pseudo brake fluid pressure generated in the master cylinder 34. The brake fluid pressure sensor Pp has a function of detecting the brake fluid pressure on the downstream side of the second master cut valve 60b.

  The stroke simulator 64 is connected to the master cylinder 34 through a branch pipe 22g branched from the pipe tube 22d. The branch pipe 22g is provided with a normally closed stroke simulator valve 62 that opens or shuts off the branch pipe 22g. As shown in FIG. 1, the stroke simulator valve 62 is subjected to excitation control (the branch pipe 22g is opened) during normal operation of the vehicle braking device 10. As a result, the stroke simulator 64 absorbs the pseudo brake fluid pressure generated in the master cylinder 34 in a state where the branch pipe 22g is opened, and thereby simulates the brake operation of the brake pedal 12 by the driver. The role of creating a natural reaction force.

  The ESB device 16 has a function of generating a brake fluid pressure in accordance with the pseudo brake fluid pressure generated in the master cylinder 34 or regardless of the pseudo brake fluid pressure generated in the master cylinder 34. As shown in FIG. 1, the ESB device 16 includes a braking motor 73, first and second slave pistons 88a and 88b, and the like. The first and second slave pistons 88a and 88b receive the rotational driving force of the braking motor 73 and generate a braking fluid pressure.

  The CDR (Collision Damage Reducing) device 17 determines whether or not there is a possibility of collision of the host vehicle, and when it is determined that there is a possibility of collision of the host vehicle, the CDR device 18 (or ESB device 16). It has a function of generating a pre-collision braking force to reduce the collision damage of the host vehicle in cooperation. Details of the CDR device 17 will be described later.

The VSA device 18 includes an ABS function for preventing wheel locking during braking operation, a TCS (traction control system) function for preventing wheel slipping during acceleration, etc., a function for suppressing side slipping during turning, and the own vehicle The vehicle has a function of performing emergency braking control (details will be described later) regardless of the driver's braking operation when there is a possibility of collision or when the host vehicle collides. In order to realize such various functions, the VSA device 18 supports the stabilization of the behavior of the host vehicle by adjusting the brake fluid pressure generated by the ESB device 16, and performs the braking control of the host vehicle.
The ESB device 16 and the VSA device 18 correspond to the “braking force generation unit” of the present invention.

  More specifically, the VSA device 18 drives the brake fluid pressure sensor Ph that detects the brake fluid pressure generated in the slave cylinder 35 of the ESB device 16, the pressure pump 136 for pressurizing the brake fluid, and the pressure pump 136. And a regulator valve 116, a first in valve 120, a second in valve 124, a first out valve 128, a second out valve 130, a reservoir 132, a suction valve 142, and the like. ing.

  In order to adjust the VSA brake hydraulic pressure by operating the VSA device 18, the following procedure may be adopted. First, the VSA device 18 drives the pressurizing pump 136 using a pump motor (pressurizing motor) 135 with the normally closed suction valve 142 provided in the liquid supply path excited and opened. Then, the brake fluid sucked through the suction valve 142 and pressurized by the pressure pump 136 is supplied to the regulator valve 116, the first in valve 120, and the second in valve 124, respectively.

  The VSA device 18 excites the regulator valve 116 and adjusts the opening thereof, thereby adjusting the VSA brake fluid pressure to the target fluid pressure and opening the brake fluid adjusted to the target fluid pressure. The oil is supplied to the wheel cylinders 32FR, 32RL, 32RR, and 32FL via the in-valve 120 and the second in-valve 124, respectively. Thereby, the VSA device 18 controls the braking force of the four wheels to the braking force corresponding to the target hydraulic pressure for each wheel even when the driver does not operate the brake pedal 12.

Further, for example, it is assumed that the right front wheel (FR) falls into a lock tendency (slip tendency) during braking. In such a case, the following procedure may be adopted to adjust the VSA braking fluid pressure related to the right front wheel (FR) by the operation of the VSA device 18.
In other words, the VSA device 18 first excites and closes the normally-open first in-valve 120 provided in the hydraulic pressure path related to the right front wheel (FR) and closes the normally-open first out-valve 128. Energized to open the valve. As a result, the brake fluid pressure acting on the wheel cylinder 32FR of the right front wheel (FR) is reduced to a predetermined pressure by letting it escape to the reservoir 132. Thereafter, the first out valve 128 is demagnetized and closed. As a result, the brake fluid pressure acting on the wheel cylinder 32FR of the right front wheel (FR) is maintained.
As a result, when the tendency to lock the right front wheel (FR) is resolved, the first in-valve 120 is demagnetized and opened, and the first out valve 128 is demagnetized and closed. As a result, the brake fluid pressure (pressurized by the pressure pump 136 as necessary) from the ESB device 16 located on the upstream side of the VSA device 18 acts on the wheel cylinder 32FR of the right front wheel (FR). The pressure is increased to a predetermined pressure.
If the right front wheel (FR) falls into a locking tendency again due to this pressure increase, the above-described procedure of pressure reduction → holding → pressure increase is repeated. As a result, the VSA device 18 can perform ABS braking control that shortens the braking distance while suppressing a situation where the right front wheel (FR) falls into the locked state (slip state).
In the above description, the ABS braking control in the case where the right front wheel (FR) falls into the lock tendency has been described as an example. The ABS braking control can be performed using a procedure according to the above.

  The other elements in FIG. 1 are not directly related to the present invention, and thus the description thereof is omitted.

[Basic operation of vehicle braking device 10]
Next, the basic operation of the vehicle braking device 10 will be described.
In the vehicle braking device 10, when a driver performs a braking operation on the brake pedal 12 during normal operation of an ESB-ECU 29 (see FIG. 2) that controls the ESB device 16, a so-called by-wire type braking system is provided. Become active.

  Specifically, in the vehicle braking device 10 during normal operation, when the driver brakes the brake pedal 12, the first and second master cut valves 60a and 60b are shut off as shown in FIG. In a state where the stroke simulator valve 62 is opened, the disc brake mechanisms 30a to 30d are operated using the brake fluid pressure generated by the ESB device 16.

  At this time, the brake fluid flows from the master cylinder 34 into the stroke simulator 64 via the stroke simulator valve 62. For this reason, even if the first and second master cut valves 60a and 60b are shut off, a brake fluid flows from the master cylinder 34 to the stroke simulator 64, so that a stroke occurs in the brake pedal 12.

  On the other hand, in the vehicular braking device 10, for example, when the driver brakes the brake pedal 12 when the ESB device 16 enters an abnormal state, the existing hydraulic brake system becomes active. Specifically, in the vehicular braking apparatus 10 at the time of abnormality, when the driver brakes the brake pedal 12, the first and second master cut valves 60a and 60b are opened, and the stroke simulator valve 62 is turned on. In the shut-off state, the brake fluid pressure generated in the master cylinder 34 is transmitted to the wheel cylinders 32FR, 32RL, 32RR, 32FL of the disc brake mechanisms 30a-30d, and the disc brake mechanisms 30a-30d are operated.

[Peripheral structure of ESB-ECU 29, CDR-ECU 30, and VSA-ECU 31 of vehicle braking device 10]
Next, the peripheral configuration of the ESB-ECU 29, the CDR-ECU 30, and the VSA-ECU 31 included in the vehicle braking apparatus 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is an explanatory diagram showing the peripheral configuration of the ESB-ECU 29, the CDR-ECU 30, and the VSA-ECU 31 that the vehicle braking device 10 has.

  As shown in FIG. 2, the ESB-ECU 29, the CDR-ECU 30, and the VSA-ECU 31 are connected to each other so as to be able to communicate with each other via a CAN communication medium 37, for example.

  The CAN communication medium 37 is a multiplexed serial communication network generally used for information communication between in-vehicle devices. The CAN communication medium 37 has an excellent data transfer rate and error detection capability. However, the “information communication medium” used in the embodiment of the present invention is not limited to the CAN communication medium 37. As the “information communication medium” used in the embodiment of the present invention, for example, “FlexRay (registered trademark)” may be adopted.

[Configuration of ESB-ECU 29]
As shown in FIG. 2, the ESB-ECU 29 includes, as an input system, an ignition key switch (hereinafter abbreviated as “IG key switch”) 121, a vehicle speed sensor 123, a brake pedal sensor 125, a hall sensor 127, and a brake. Hydraulic pressure sensors Pm and Pp are connected to each other.

  The IG key switch 121 is a switch operated when power is supplied to each part of the electrical component mounted on the vehicle via an in-vehicle battery (not shown). When the IG key switch 121 is turned on, power is supplied to the ESB-ECU 29 and the VSA-ECU 31, and the ESB-ECU 29 and the VSA-ECU 31 are activated.

  The vehicle speed sensor 123 has a function of detecting the traveling speed (vehicle speed) V of the vehicle. Information on the vehicle speed V detected by the vehicle speed sensor 123 is sent to the ESB-ECU 29.

  The brake pedal sensor 125 has a function of detecting an operation amount (stroke amount) and torque of the brake pedal 12 by the driver. Information related to the operation amount and torque of the brake pedal 12 detected by the brake pedal sensor 125 is sent to the ESB-ECU 29.

  The hall sensor 127 has a function of detecting the rotation angle of the brake motor 73 (current position information in the axial direction of the slave pistons 88a and 88b). Information regarding the rotation angle of the braking motor 73 detected by the hall sensor 127 is sent to the ESB-ECU 29.

  The brake fluid pressure sensors Pm and Pp have a function of detecting the upstream fluid pressure of the first master cut valve 60a and the downstream fluid pressure of the second master cut valve 60b in the brake fluid pressure system, respectively. The hydraulic pressure information of each part in the braking hydraulic system detected by the braking hydraulic pressure sensors Pm, Pp is sent to the ESB-ECU 29.

  On the other hand, as shown in FIG. 2, the ESB-ECU 29 is connected with the braking motor 73, the first and second master cut valves 60a and 60b, and the stroke simulator valve 62 as output systems. .

  As shown in FIG. 2, the ESB-ECU 29 includes a first information acquisition unit 71 and a first braking control unit 77.

  The first information acquisition unit 71 includes information related to the on / off operation of the IG key switch 121, information related to the vehicle speed V detected by the vehicle speed sensor 123, an operation amount of the brake pedal 12 detected by the brake pedal sensor 125, and It has a function of acquiring information related to braking torque, rotation angle information of the braking motor 73 detected by the hall sensor 127, information related to braking fluid pressure of each part detected by the braking fluid pressure sensors Pm, Pp, and the like.

  Further, the first information acquisition unit 71 receives collision information related to the presence or absence of a collision of the host vehicle and hydraulic pressure information detected by the braking hydraulic pressure sensor Ph sent from the VSA-ECU 31 via the CAN communication medium 37. It has the function to acquire.

  The first braking control unit 77 is basically generated in the ESB device 16 based on information related to the braking operation acquired by the first information acquisition unit 71, information related to the braking hydraulic pressure of each unit, and the like. The brake fluid pressure has a function of controlling the brake fluid pressure applied to the wheel cylinder 32 so that the brake fluid pressure follows the target brake fluid pressure corresponding to the braking operation.

  Even when the first braking control unit 77 receives collision information indicating that the host vehicle has collided, the first and second master cut valves are used when the vehicle braking device 10 is operating normally. 60a and 60b are closed, the flow of the brake fluid between the master cylinder 34 and the slave cylinder 35 is shut off, and the stroke simulator valve 62 is opened.

  The ESB-ECU 29 is configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The microcomputer reads out and executes programs and data stored in the ROM, and has various information acquisition functions including collision information related to the presence or absence of a collision of the host vehicle, which the ESB-ECU 29 has, and braking fluid applied to the wheel cylinder 32 It operates to perform execution control related to various functions including the pressure control function.

[Configuration of CDR-ECU 30]
A laser radar (not shown) and a vehicle-mounted camera are connected to the CDR-ECU 30 (see FIG. 2) that controls the CDR device 17.

  The laser radar has a function of acquiring target information related to the distribution of a target (object or sign) existing in the forward direction of the host vehicle. The laser radar is provided, for example, on the back of the front grill of the host vehicle. The target information related to the forward direction of the own vehicle detected by the laser radar is referred to when the possibility of collision of the own vehicle is determined by the collision possibility determination unit 171 described later of the CDR-ECU 30.

  The in-vehicle camera has an optical axis inclined obliquely downward in front of the host vehicle, and has a function of acquiring image information related to the forward direction of the host vehicle. As the in-vehicle camera, for example, a complementary metal oxide semiconductor (CMOS) camera, a charge coupled device (CCD) camera, or the like can be used as appropriate. The in-vehicle camera is provided, for example, at the upper center of the windshield of the host vehicle. Image information related to the forward direction of the host vehicle captured by the in-vehicle camera is referred to when the collision possibility determination unit 171 described later of the CDR-ECU 30 determines whether the host vehicle is likely to collide.

  The CDR-ECU 30 includes a collision possibility determination unit 171. The collision possibility determination unit 171 refers to the target information related to the forward direction of the own vehicle detected by the laser radar and the image information related to the forward direction of the own vehicle captured by the in-vehicle camera, and collides with the own vehicle. It has a function to determine the possibility. When the collision possibility determination unit 171 determines that there is a possibility of collision of the host vehicle, the CDR-ECU 30 transmits information indicating that the host vehicle is likely to collide with the VSA- via the CAN communication medium 33. It sends to ECU31.

  The CDR-ECU 30 is constituted by a microcomputer including a CPU, a ROM, a RAM, and the like. The microcomputer includes a function of reading out and executing a program and data stored in the ROM and transmitting the information indicating that the CDR-ECU 30 has a collision possibility determination function and a possibility of collision of the host vehicle. Controls related to various functions.

[Configuration of VSA-ECU 31]
As shown in FIG. 2, a wheel speed sensor 150, an accelerator pedal sensor 151, a yaw rate sensor 152, a G sensor 153, a steering angle sensor 155, and a brake fluid pressure sensor Ph are connected to the VSA-ECU 31, respectively.

  The wheel speed sensors 150a to 150d have a function of detecting the rotation speed (wheel speed) for each wheel. Information on the rotational speed of each wheel detected by each of the wheel speed sensors 150a to 150d is sent to the VSA-ECU 31.

  The accelerator pedal sensor 151 has a function of detecting the amount of operation (stroke amount) of the accelerator pedal by the driver. Information related to the operation amount of the accelerator pedal detected by the accelerator pedal sensor 151 is sent to the VSA-ECU 31.

  The yaw rate sensor 152 has a function of detecting the yaw rate occurring in the host vehicle. Information related to the yaw rate detected by the yaw rate sensor 152 is sent to the VSA-ECU 31.

  The G sensor 153 has a function of detecting front and rear G (front / rear acceleration / deceleration) and lateral G (lateral acceleration / deceleration) occurring in the host vehicle. Information relating to the acceleration / deceleration of the own vehicle detected by the G sensor 153 (the absolute value of the acceleration / deceleration of the own vehicle) is sent to the VSA-ECU 31.

  The steering angle sensor 155 has a function of detecting the steering amount and steering direction of the steering. Information related to the steering angle of the steering detected by the steering angle sensor 155 is sent to the VSA-ECU 31.

  The brake fluid pressure sensor Ph has a function of detecting the brake fluid pressure in the fluid supply path of the VSA device 18 in the brake fluid pressure system. The hydraulic pressure information in the liquid supply path of the VSA device 18 detected by the brake hydraulic pressure sensor Ph is sent to the ESB-ECU 29.

  On the other hand, as shown in FIG. 2, the pump motor (pressurizing motor) 135 is connected to the VSA-ECU 31 as an output system.

  The VSA-ECU 31 includes a second information acquisition unit (information acquisition unit) 161, a collision determination unit 163, and a second braking control unit (braking control unit) 167.

  The second information acquisition unit 161 adds information related to the rotational speed (wheel speed) for each wheel detected by the wheel speed sensors 150a to 150d and an accelerator pedal (not shown) detected by the accelerator pedal sensor 151. Information relating to the deceleration operation amount, information relating to the yaw rate occurring in the vehicle detected by the yaw rate sensor 152, information relating to the longitudinal G and lateral G occurring in the vehicle detected by the G sensor 153, steering angle sensor Information regarding the steering angle detected at 155 and hydraulic pressure information in the liquid supply path of the VSA device 18 detected by the brake hydraulic pressure sensor Ph are obtained.

  The second information acquisition unit 161 has a function of acquiring information related to the vehicle speed V and information related to the operation amount of the brake pedal 12 sent from the ESB-ECU 29 via the CAN communication medium 37.

  Further, the second information acquisition unit 161 has a function of acquiring information indicating that there is a possibility of collision of the host vehicle, which is sent from the CDR-ECU 30 via the CAN communication medium 37. The information indicating that there is a possibility of collision of the host vehicle acquired by the second information acquisition unit 161 is referred to when the collision determination unit 163 sets the collision determination threshold Cth for determining whether or not the host vehicle has a collision. .

  The collision determination unit 163 has a function of performing a determination related to the presence or absence of a collision of the host vehicle using the collision determination threshold value Cth for determining whether or not the host vehicle has a collision. Specifically, the collision determination unit 163 determines that the host vehicle has collided when the acceleration / deceleration (absolute value) of the host vehicle detected by the G sensor 153 exceeds a predetermined collision determination threshold Cth. Down.

  More specifically, the collision determination unit 163 performs the pre-collision braking control (collision damage reduction braking control) when the second information acquisition unit 161 has not acquired information indicating that there is a possibility of collision of the host vehicle. Collision determination is performed using the reference collision determination threshold value Cth0 (see FIG. 5) as the collision determination threshold value Cth when not performed. For example, the reference collision determination threshold Cth0 is set to a value common to a threshold used when determining whether or not an airbag device (not shown) installed in the host vehicle is necessary.

Further, the collision determination unit 163 obtains the collision determination threshold value Cth after the information indicating that the host vehicle is likely to collide is acquired by the second information acquisition unit 161, that is, after the pre-collision braking control is performed. A value Cth1 (Cth1 <Cth0; see FIG. 5) that is lower than the reference collision determination threshold Cth0 is used.
Information on the determination result relating to the presence or absence of a collision of the host vehicle made by the collision determination unit 163 is referred to as appropriate when the second braking control unit 167 determines whether or not to perform post-collision braking control.

The second braking control unit 167, when information indicating that there is a possibility of collision of the host vehicle is acquired by the second information acquisition unit 161, the braking force before the collision for reducing the collision damage of the host vehicle ( When the pre-collision braking control for causing the VSA device 18 to generate a pre-collision braking characteristic shown in FIG. 4 is performed and the collision determination unit 163 determines that there is a collision, the post-collision braking force Post-collision braking control is performed to cause the VSA device 18 to generate (see the post-collision braking characteristics shown in FIG. 4). The post-collision braking force is set larger than the pre-collision braking force (see FIG. 4).
The second braking control unit 167 corresponds to the “braking control unit” of the present invention.

  The VSA-ECU 31 is constituted by a microcomputer including a CPU, a ROM, a RAM, and the like. This microcomputer reads out and executes programs and data stored in the ROM, and the VSA-ECU 31 has a function of acquiring various types of information including information that there is a possibility of collision of the host vehicle, whether there is a collision of the host vehicle. The function to perform the judgment related to the vehicle, the function to perform the pre-collision braking control when the information indicating that there is a possibility of collision of the own vehicle, and the braking after the collision when the judgment of the presence of the collision of the own vehicle is made. Control related to various functions including the function of performing control is performed.

[Description of Operation of Vehicle Braking Device 10 Based on Flowchart]
Next, operation | movement of the braking device 10 for vehicles which concerns on embodiment of this invention is demonstrated with reference to FIGS. FIG. 3 is a flowchart for explaining the operation of the vehicle braking device 10. FIG. 4 is an explanatory diagram that compares and compares the braking characteristics used before the collision of the host vehicle and the braking characteristics used after the collision of the host vehicle. FIG. 5 is an explanatory diagram showing a comparison between the reference collision determination threshold and the collision determination threshold after the pre-collision braking control is performed.

  In step S11 illustrated in FIG. 3, the CDR-ECU 30 includes various pieces of information including target information related to the forward direction of the host vehicle detected by the laser radar and image information related to the forward direction of the host vehicle captured by the in-vehicle camera. To get.

  In step S12, the collision possibility determination unit 171 of the CDR-ECU 30 obtains target information related to the forward direction of the host vehicle detected by the laser radar and image information related to the forward direction of the host vehicle captured by the in-vehicle camera. With reference to, the possibility of collision of the host vehicle is determined. In determining the possibility of collision of the host vehicle, a known technique as disclosed in, for example, Japanese Patent Laid-Open No. 2008-181200 may be applied as appropriate.

As a result of the determination in step S12, when it is determined that there is no possibility of collision of the host vehicle (“No” in step S12), the CDR-ECU 30 returns the process flow to step S11, and the collision of the host vehicle is detected. The loop processing of steps S11 to S12 is repeated until it is determined that there is a possibility.
Although not shown in FIG. 3 during the loop processing of steps S11 to S12, the collision determination unit 163 uses the reference collision determination threshold Cth0 (see FIG. 5) as the collision determination threshold Cth to determine whether or not the host vehicle has a collision. The determination which concerns on is performed. As a result of this determination, when it is determined that there is a collision of the host vehicle, the second braking control unit 167 of the VSA-ECU 31 generates a post-collision braking force (see the post-collision braking characteristics shown in FIG. 4). The post-collision braking control is performed. Since the flow of such processing belongs to known technical matters, detailed description thereof is omitted.

  As a result of the determination in step S12, when it is determined that there is a possibility of collision of the host vehicle (“Yes” in step S12), the CDR-ECU 30 changes the process flow to time-division parallel processing (step S13, and Go to step S18). In the time-division parallel processing, the VSA-ECU 31 apparently performs loop processing (collision determination processing during braking control before collision) related to steps S13 to S17 and loop processing (brake control processing) related to steps S18 to S23. Do at the same time.

  In step S13, the collision determination unit 163 of the VSA-ECU 31 sets a collision determination threshold Cth1 (Cth1 <Cth0; see FIG. 5), which is lower than the reference collision determination threshold Cth0, as the collision determination threshold Cth (Cth = Cth1).

In step S14, the VSA-ECU 31 determines whether or not a predetermined delay time Td has elapsed from the start of execution of the pre-collision braking control by the second braking control unit 167. This delay time Td is a collision determination using a collision determination threshold value Cth1 (Cth1 <Cth0; see FIG. 5) that is lower than the reference collision determination threshold value Cth0 after the pre-collision braking control is actually performed. It is provided in order to guarantee that step S16) is performed. Therefore, the VSA-ECU 31 repeats the process of step S14 until it is determined that the predetermined delay time Td has elapsed since the execution start of the pre-collision braking control.
As a result of the determination in step S14, when it is determined that the delay time Td has elapsed from the start of execution of the pre-collision braking control, the VSA-ECU 31 advances the process flow to the next step S15.

  In step S <b> 15, the second information acquisition unit 161 of the VSA-ECU 31 acquires various types of information including information related to acceleration / deceleration of the host vehicle detected by the G sensor 153.

  In step S16, the collision determination unit 163 of the VSA-ECU 31 uses the collision determination threshold Cth1 set in step S13 to determine whether or not the host vehicle has a collision.

As a result of the determination in step S16, if the collision determination unit 163 determines that there is no collision of the host vehicle (“No” in step S16), the VSA-ECU 31 returns the process flow to step S15, The loop process of steps S15 to S16 is repeated until the collision determination unit 163 determines that there is a vehicle collision (“Yes” in step S16).
On the other hand, as a result of the determination in step S16, when the collision determination unit 163 determines that there is a collision of the host vehicle (“Yes” in step S16), the VSA-ECU 31 proceeds to the next step S17. Go to.

  In step S17, the second braking control unit 167 of the VSA-ECU 31 issues a braking force update request for updating the pre-collision braking force that has been applied to the host vehicle to the post-collision braking force. Thereafter, the VSA-ECU 31 returns the process flow to step S15, and sequentially executes the subsequent processes.

  Meanwhile, in step S18, the second braking control unit 167 of the VSA-ECU 31 initializes a pre-collision braking force (see the pre-collision braking characteristics shown in FIG. 4) as a braking force generated by the VSA device 18. .

  In step S19, the second braking control unit 167 of the VSA-ECU 31 uses the braking force initially set in step S18 (before the collision) or the braking force updated in step S22 described later (after the collision). To execute braking control.

  In step S20, the VSA-ECU 31 determines whether or not the pre-collision braking control end condition (pre-collision end condition) is satisfied. Here, as the pre-collision end condition, for example, it may be adopted that the host vehicle stops (the vehicle speed V is 0 km / h) before a predetermined waiting time Tw1 has elapsed since the start of the pre-collision braking control. . This is because, after satisfying the pre-collision termination conditions, the host vehicle is in a stopped state, so that it is assumed that no trouble will occur even if the pre-collision braking control is terminated.

As a result of the determination in step S20, when it is determined that the pre-collision end condition is satisfied (“Yes” in step S20), the VSA-ECU 31 jumps the process flow to step S24.
On the other hand, as a result of the determination in step S20, if it is determined that the pre-collision termination condition is not satisfied (including the case where the post-collision braking control is performed in step S19) ("No" in step S20). The VSA-ECU 31 advances the process flow to the next step S21.

  In step S21, the second braking control unit 167 of the VSA-ECU 31 determines whether a braking force update request has been issued.

  If it is determined in step S21 that the braking force update request has not been issued (“No” in step S21), the VSA-ECU 31 returns the process flow to step S19, and the subsequent processes. Are executed sequentially.

  On the other hand, if it is determined in step S21 that a braking force update request has been issued (“Yes” in step S21), the VSA-ECU 31 advances the process flow to the next step S22. Make it.

  In step S22, the second braking control unit 167 of the VSA-ECU 31 updates and sets the post-collision braking force (see the post-collision braking characteristics shown in FIG. 4) as the braking force generated by the VSA device 18.

  In step S23, the VSA-ECU 31 determines whether or not a post-collision braking control end condition (post-collision end condition) is satisfied. Here, as the post-collision end condition, for example, the host vehicle stops (the vehicle speed V is 0 km / h), and a predetermined waiting time Tw2 from the time of the collision (however, it may be the time of starting the braking control after the collision). It may be adopted that has passed. This is because, after satisfying such a post-collision termination condition, the host vehicle is in a stopped state, and therefore it is assumed that no trouble will occur even if the post-collision braking control is terminated.

  As a result of the determination in step S23, if it is determined that the post-collision end condition is not satisfied ("No" in step S23), the VSA-ECU 31 returns the process flow to step S19, and sets the post-collision end condition. Until it is determined that the vehicle is satisfied, the process related to the braking control (after the collision) in step S19 is continued.

  On the other hand, as a result of the determination in step S23, if it is determined that the post-collision termination condition is satisfied (“Yes” in step S23), the VSA-ECU 31 advances the process flow to the next step S24. .

  In step S24, the VSA-ECU 31 ends the series of processing flow after ending the processing related to the braking control in step S19.

[Effect of the braking device 10 for a vehicle according to the embodiment of the present invention]
Next, the effect of the vehicle braking device 10 according to the embodiment of the present invention will be described.
The vehicle braking device 10 according to the first aspect (corresponding to claim 1) includes a VSA device (braking force generation unit) 18 that generates a braking force for braking the host vehicle and the possibility of collision of the host vehicle. A second information acquisition unit (information acquisition unit) 161 that acquires information related to the vehicle, a collision determination unit 163 that determines the presence or absence of a collision of the host vehicle using the collision determination threshold Cth, and the possibility that the host vehicle may collide Is acquired by the second information acquisition unit 161, the pre-collision braking control is generated to cause the VSA device 18 to generate the pre-collision braking force for reducing the collision damage of the own vehicle. A second braking control unit (braking control unit) 167 that performs post-collision braking control that causes the VSA device 18 to generate post-collision braking force when a determination of presence is made by the collision determination unit 163;
The collision determination unit 163 uses a value Cth1 that is lower than the (reference) collision determination threshold Cth0 when the pre-collision braking control is not performed as the collision determination threshold Cth after the pre-collision braking control is performed.

  In the vehicle braking device 10 based on the first aspect, information indicating that there is a possibility of collision of the own vehicle is acquired, and the braking control for generating the pre-collision braking force for reducing the collision damage of the own vehicle is performed. A case is assumed in which the vehicle encounters a collision accident even though it has been done before. In this case, if the braking control that generates the pre-collision braking force is performed before the collision, the speed of the own vehicle may indicate that there is a possibility of collision of the own vehicle when the own vehicle actually encounters a collision accident. The speed is reduced compared to the speed at the time when the information was acquired. Therefore, the deceleration that occurs in the host vehicle when the host vehicle actually encounters a collision accident is reduced as compared with the case where the braking control that generates the pre-collision braking force is not performed before the collision. As a result, although the own vehicle actually encounters a collision accident, the collision determination unit makes an erroneous determination that the own vehicle is not colliding, and braking control that generates a braking force after the collision is performed. There is concern that it will not be done.

  Therefore, in the vehicle braking device 10 based on the first aspect, the collision determination unit 163 performs the pre-collision braking control as the collision determination threshold Cth after the pre-collision braking control is performed by the second braking control unit 167. A configuration using a lower value Cth1 than the (reference) collision determination threshold Cth0 when not performed by the second braking control unit 167 is adopted.

  According to the vehicle braking device 10 based on the first aspect, the host vehicle has encountered a collision accident even though the braking control for generating the pre-collision braking force for reducing the collision damage of the host vehicle has been performed. Even in this case, the braking control of the host vehicle can be performed accurately.

  The vehicle braking device 10 based on the second aspect (corresponding to claim 2) is the vehicle braking device 10 based on the first aspect, and the second braking control unit (braking control unit) 167 is When the collision determination unit 163 determines that the host vehicle has a collision, the post-collision braking control is performed to cause the VSA device 18 to generate a post-collision braking force that is set to be larger than the pre-collision braking force. It is characterized by.

  According to the vehicle braking apparatus 10 based on the second aspect, the second braking control unit 167 compares the braking force before collision when the collision determination unit 163 determines that the vehicle has a collision. Because the post-collision braking control that causes the VSA device 18 to generate a large post-collision braking force is performed, the braking distance after the collision of the host vehicle is shortened compared to the case of performing the braking control that maintains the pre-collision braking force. You can expect the effect.

[Other Embodiments]
The plurality of embodiments described above show examples of realization of the present invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by these. This is because the present invention can be implemented in various forms without departing from the gist or main features thereof.

  For example, in the embodiment according to the present invention, when it is determined that there is a possibility of collision of the host vehicle, the VSA-ECU 31 changes the processing flow to time-division parallel processing (loop processing according to steps S13 to S17; Although an example of the transition to the collision determination process during the braking control and the loop process (braking control process according to steps S18 to S23) has been described, the present invention is not limited to this example. Instead of the time-division parallel processing, a configuration in which each of the plurality of CPUs performs a collision determination process and a braking control process during the braking control before the collision by using a VSA-ECU 31 having a plurality of CPUs operating in cooperation with each other. May be adopted.

  Further, in the embodiment according to the present invention, the pre-collision braking characteristic (a pre-collision braking characteristic that maintains a predetermined deceleration regardless of the change in the vehicle speed V) as the pre-collision braking force generated by the second braking control unit 167 of the VSA-ECU 31 ( Although the braking force according to FIG. 4 was illustrated and demonstrated, this invention is not limited to this example. As the pre-collision braking force, for example, a braking force according to a braking characteristic that changes (decreases) the deceleration according to a change (increase) in the vehicle speed V may be adopted.

  Further, in the embodiment according to the present invention, as the post-collision braking force generated by the second braking control unit 167 of the VSA-ECU 31, the post-collision that changes (decreases) the deceleration according to the change (increase) of the vehicle speed V. Although the braking force according to the braking characteristic (see FIG. 4) has been described as an example, the present invention is not limited to this example. As the post-collision braking force, for example, a braking force according to a braking characteristic that maintains a predetermined deceleration regardless of changes in the vehicle speed V may be employed.

  Further, as the post-collision braking force generated by the second braking control unit 167 of the VSA-ECU 31, the braking according to the post-collision braking characteristic that increases the deceleration related to braking in response to an increase in the deceleration during the collision. Power may be employed.

  Finally, in the embodiment according to the present invention, the CDR device 17 has been described with reference to an example of executing the pre-collision braking control for reducing the collision damage of the host vehicle in cooperation with the VSA device 18. The invention is not limited to this example. The CDR device 17 may cooperate with the ESB device 16 (in place of the VSA device 18), or may adopt a mode of executing the pre-collision braking control in cooperation with the ESB device 16 and the VSA device 18.

10 Vehicle braking device 16 ESB device (braking force generator)
18 VSA device (braking force generator)
161 2nd information acquisition part (information acquisition part)
163 Collision determination unit 167 Second braking control unit (braking control unit)

Claims (2)

A braking force generator for generating a braking force for braking the host vehicle;
An information acquisition unit for acquiring information related to the possibility of collision of the host vehicle;
A collision determination unit that determines the presence or absence of a collision of the host vehicle using a collision determination threshold;
Pre-collision braking control for causing the braking force generation unit to generate a pre-collision braking force for reducing the collision damage of the own vehicle when information indicating that there is a possibility of collision of the own vehicle is acquired by the information acquisition unit And a braking control unit that performs post-collision braking control that causes the braking force generation unit to generate post-collision braking force when the collision determination unit determines that the vehicle has a collision, and
The collision determination unit uses a lower value than the collision determination threshold when the pre-collision braking control is not performed as the collision determination threshold after the pre-collision braking control is performed. Vehicle braking device. The vehicle braking device according to claim 1,
The braking control unit applies the post-collision braking force that is set larger than the pre-collision braking force to the braking force generation unit when the collision determination unit determines that the vehicle has a collision. A braking device for a vehicle, which performs braking control after collision to be generated.

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