WO2020111163A1

WO2020111163A1 - Braking control device

Info

Publication number: WO2020111163A1
Application number: PCT/JP2019/046483
Authority: WO
Inventors: 雅敏半澤
Original assignee: 株式会社アドヴィックス
Priority date: 2018-11-30
Filing date: 2019-11-28
Publication date: 2020-06-04
Also published as: JP2020083287A; JP7222233B2

Abstract

The present invention relates to a braking control device applicable to a vehicle provided with an electric brake device which causes an electric braking force to be generated in a left wheel by driving a left motor provided on a left wheel side, and causes an electric braking force to be generated in a right wheel by driving a right motor provided on a right wheel side. If a drive request has been issued with respect to the electric brake device, an electric brake control unit: calculates a target braking force required to hold a stopped vehicle; calculates a left target current value, which is a target current value with respect to the left motor, and a right target current value, which is a target current value with respect to the right motor, for generating the target braking force; drives the left motor and the right motor; and carries out stopping control to stop both the left motor and the right motor simultaneously when either an actual current value of the left motor has reached to or above the left target current value, or an actual current value of the right motor has reached to or above the right target current value.

Description

Braking control device

The present invention relates to a braking control device.

In recent years, electric parking brakes (hereinafter referred to as EPBs (Electric Parking Brakes) or electric brake devices) have been widely used in various vehicles such as passenger cars. A braking control device that executes braking by EPB generates electric braking force by controlling a motor to drive a wheel braking mechanism, for example.

Also, when the braking by the EPB is executed, the stop timings of the left motor provided on the left wheel side and the right motor provided on the right wheel side may be different for various reasons.

JP, 2014-46824, A

However, when the stop timing of the left motor and the right motor is different when braking by the EPB, there is a case where the left and right operating noises are different and the passengers feel uncomfortable and uncomfortable.

Therefore, one of the objects of the present invention is to provide, for example, a braking control device that can reduce the uncomfortable feeling and the discomfort caused by the operating noise when the braking by the EPB is executed.

The present invention, for example, generates an electric braking force on the left wheel by driving a left motor provided on the left wheel side, and an electric braking force on the right wheel by driving a right motor provided on the right wheel side. A braking control device applied to a vehicle including an electric brake device for generating a vehicle, when a drive request for the electric brake device is made, a target braking force required to hold a vehicle is calculated, and the target braking force is calculated. A left target current value that is a target current value for the left motor to generate and a right target current value that is a target current value for the right motor are calculated, and the left motor and the right motor are driven to generate the left target current value. When one of the fact that the actual current value of the motor reaches or exceeds the left target current value and the actual current value of the right motor reaches or exceeds the right target current value, the left motor and the An electric brake control unit that executes stop control for stopping both of the right motors at the same time is provided.

FIG. 1 is a schematic diagram showing an overall outline of the vehicle brake device of the first embodiment. FIG. 2 is a schematic cross-sectional view of a rear wheel wheel brake mechanism provided in the vehicle brake device of the first embodiment. FIG. 3 is a flowchart showing the overall processing by the braking control device of the first embodiment. FIG. 4 is a flowchart showing a lock control process by the braking control device of the first embodiment. FIG. 5 is a flowchart showing a process of estimating an actual axial force by the braking control device of the first embodiment. FIG. 6 is a flowchart showing a process of calculating the required axial force by the braking control device of the first embodiment. FIG. 7 is a flowchart showing a follow control process by the braking control device of the first embodiment. FIG. 8 is a time chart showing a first control example in the first embodiment. FIG. 9 is a time chart showing a second control example in the first embodiment. FIG. 10 is a time chart showing a third control example in the first embodiment. FIG. 11 is a time chart showing a fourth control example in the first embodiment. FIG. 12 is a flowchart showing a lock control process by the braking control device of the second embodiment. FIG. 13 is a time chart showing a control example in the second embodiment. FIG. 14 is a flowchart showing a lock control process by the braking control device of the third embodiment. FIG. 15 is a flowchart showing the process of estimating the current axial force by the braking control device of the third embodiment. FIG. 16 is a flowchart showing a process of estimating a required axial force (variation) by the braking control device of the third embodiment. FIG. 17 is a flowchart showing a lock control process by the braking control device of the fourth embodiment. FIG. 18 is a time chart showing a control example in the fourth embodiment. FIG. 19 is a flowchart showing a lock control process by the braking control device of the fifth embodiment. FIG. 20 is a time chart showing a control example in the fifth embodiment.

Hereinafter, exemplary embodiments (first to fifth embodiments) of the present invention will be disclosed. The configurations of the embodiments shown below, and the actions and results (effects) provided by the configurations are examples. The present invention can be realized by a configuration other than the configurations disclosed in the following embodiments. Further, according to the present invention, it is possible to obtain at least one of various effects (including derivative effects) obtained by the following configurations.

(First embodiment)
In the first embodiment, a vehicle brake device in which a disc brake type EPB is applied to a rear wheel system will be described as an example. FIG. 1 is a schematic diagram showing an overall outline of the vehicle brake device of the first embodiment. FIG. 2 is a schematic cross-sectional view of a rear wheel wheel brake mechanism provided in the vehicle brake device of the first embodiment. Hereinafter, description will be given with reference to these figures.

As shown in FIG. 1, the vehicle brake device of the first embodiment includes a service brake 1 (hydraulic brake device) and an EPB 2 (electric brake device).

The service brake 1 is hydraulically applied toward the braked member (the brake disc 12 in FIG. 2) that rotates integrally with the wheels based on the driver's depression of the brake pedal 3 (the brake pad 11 in FIG. 2). ) To generate a service braking force (hydraulic braking force). Specifically, the service brake 1 boosts the pedal effort corresponding to the depression of the brake pedal 3 by the driver with the booster 4, and then applies the brake fluid pressure corresponding to the boosted pedal effort to the master cylinder ( Hereinafter, it is generated within 5). Then, the brake hydraulic pressure is transmitted to a wheel cylinder (hereinafter, referred to as W/C) 6 provided in a wheel brake mechanism of each wheel to generate a service brake force. Further, an actuator 7 for controlling brake fluid pressure is provided between M/C5 and W/C6. The actuator 7 adjusts the service brake force generated by the service brake 1 and performs various controls (for example, anti-skid control) for improving the safety of the vehicle.

Various controls using the actuator 7 are executed by ESC (Electronic Stability Control)-ECU 8 that controls the service braking force. For example, the ESC-ECU 8 outputs a control current for controlling various control valves (not shown) provided in the actuator 7 and a motor for driving the pump, thereby controlling the hydraulic circuit provided in the actuator 7, and the W/C 6 It controls the W/C pressure transmitted to. As a result, wheel slip is avoided and the safety of the vehicle is improved.

For example, the actuator 7 controls, for each wheel, a pressure increase control that controls whether the brake fluid pressure generated in the M/C5 or the brake fluid pressure generated by the pump drive is applied to the W/C6. It is equipped with a valve and a pressure reduction control valve that reduces the W/C pressure by supplying the brake fluid in each W/C 6 to the reservoir, and is configured to increase/hold/depress the W/C pressure. ing. Further, the actuator 7 can realize the automatic pressurizing function of the service brake 1, and automatically applies the W/C 6 based on the control of the pump drive and various control valves even when the brake is not operated. You can press.

On the other hand, the EPB 2 is for generating an electric braking force by driving the wheel braking mechanism by the motor 10, and has an EPB-ECU 9 (braking control device. electric braking control unit) for controlling the driving of the motor 10. It is configured. Specifically, for example, the EPB 2 drives the motor 10 toward the braked member (the brake disc 12 in FIG. 2) so that the vehicle does not move unintentionally during parking, and thus the brake member (in FIG. 2). The brake pad 11) is pressed to generate an electric braking force. The EPB-ECU 9 and the ESC-ECU 8 send and receive information by CAN (Controller Area Network) communication, for example.

The wheel brake mechanism is a mechanical structure that generates a braking force in the vehicle brake device of the first embodiment. First, the front wheel system wheel brake mechanism has a structure that generates a service braking force by operating the service brake 1. ing. On the other hand, the wheel brake mechanism of the rear wheel system has a common structure that generates a braking force for both the operation of the service brake 1 and the operation of the EPB 2. The front wheel brake mechanism is a wheel brake mechanism that has been generally used since the rear wheel brake mechanism does not include a mechanism that generates an electric braking force based on the operation of EPB2. The description is omitted here, and the wheel brake mechanism of the rear wheel system will be described below.

In the wheel brake mechanism of the rear wheel system, not only when the service brake 1 is operated but also when the EPB 2 is operated, the brake pad 11 which is a friction material shown in FIG. By sandwiching the brake disc 12 (12RL, 12RR, 12FR, 12FL) which is a material, a frictional force is generated between the brake pad 11 and the brake disc 12, and a braking force is generated.

Specifically, the wheel brake mechanism rotates the motor 10 directly fixed to the body 14 of the W/C 6 for pressing the brake pad 11 as shown in FIG. 2 in the caliper 13 shown in FIG. As a result, the spur gear 15 provided on the drive shaft 10a of the motor 10 is rotated. Then, by transmitting the rotational force (output) of the motor 10 to the spur gear 16 meshed with the spur gear 15, the brake pad 11 is moved to generate the electric braking force by the EPB 2.

In addition to the W/C 6 and the brake pad 11, a part of the end surface of the brake disc 12 is housed in the caliper 13 so as to be sandwiched by the brake pad 11. The W/C 6 can generate the W/C pressure in the hollow portion 14a which is the brake fluid storage chamber by introducing the brake fluid pressure into the hollow portion 14a of the cylindrical body 14 through the passage 14b. The hollow portion 14a is provided with a rotary shaft 17, a propulsion shaft 18, a piston 19 and the like.

The rotary shaft 17 has one end connected to the spur gear 16 through an insertion hole 14c formed in the body 14, and when the spur gear 16 is rotated, it is rotated together with the rotation of the spur gear 16. A male screw groove 17a is formed on the outer peripheral surface of the rotary shaft 17 at the end of the rotary shaft 17 opposite to the end connected to the spur gear 16. On the other hand, the other end of the rotary shaft 17 is supported by being inserted into the insertion hole 14c. Specifically, the insertion hole 14c is provided with a bearing 21 together with the O-ring 20, and the O-ring 20 prevents the brake fluid from leaking out between the rotary shaft 17 and the inner wall surface of the insertion hole 14c. Meanwhile, the other end of the rotary shaft 17 is axially supported by the bearing 21.

The propulsion shaft 18 is composed of a nut made of a hollow cylindrical member, and has an internal wall surface formed with a female screw groove 18a that is screwed into the male screw groove 17a of the rotary shaft 17. The propulsion shaft 18 is configured to have, for example, a columnar shape or a polygonal columnar shape provided with a key for preventing rotation, so that even if the rotation shaft 17 rotates, the propulsion shaft 18 is rotated about the rotation center of the rotation shaft 17. There is no structure. Therefore, when the rotating shaft 17 is rotated, the rotational force of the rotating shaft 17 becomes a force for moving the propulsion shaft 18 in the axial direction of the rotating shaft 17 due to the engagement between the male screw groove 17a and the female screw groove 18a. Convert. When the driving of the motor 10 is stopped, the propulsion shaft 18 stops at the same position due to the frictional force due to the engagement between the male screw groove 17a and the female screw groove 18a, and the target electric braking force is obtained. If the drive of the motor 10 is stopped at that time, the propulsion shaft 18 is held at that position, and a desired electric braking force can be held and self-locking (hereinafter simply referred to as "lock") can be performed.

The piston 19 is arranged so as to surround the outer periphery of the propulsion shaft 18, is configured by a bottomed cylindrical member or a polygonal cylindrical member, and has an outer peripheral surface in contact with the inner wall surface of the hollow portion 14 a formed in the body 14. Are arranged as follows. A structure in which a seal member 22 is provided on the inner wall surface of the body 14 so that the brake fluid does not leak between the outer peripheral surface of the piston 19 and the inner wall surface of the body 14, and W/C pressure can be applied to the end surface of the piston 19. It is said that. The seal member 22 is used to generate a reaction force for returning the piston 19 during release control after lock control. Since this seal member 22 is provided, basically, even if the brake pad 11 and the piston 19 are pushed in by the tilted brake disc 12 within a range not exceeding the elastic deformation amount of the seal member 22, they are braked. It can be pushed back to the side of the disc 12 so that the space between the brake disc 12 and the brake pad 11 is maintained with a predetermined clearance (clearance C2 in FIG. 2).

Further, the piston 19 does not rotate about the center of rotation of the rotary shaft 17 even if the rotary shaft 17 rotates, so that if the propulsion shaft 18 is provided with a key for preventing rotation, the key is When the propulsion shaft 18 has a polygonal column shape, it is provided with a sliding key groove, and has a polygonal cylindrical shape having a shape corresponding thereto.

The brake pad 11 is arranged at the tip of the piston 19, and the brake pad 11 is moved in the left-right direction on the paper surface as the piston 19 moves. Specifically, the piston 19 is movable to the left in the drawing with the movement of the propulsion shaft 18, and is located at the end of the piston 19 (the end opposite to the end where the brake pad 11 is arranged). By applying W/C pressure, it is configured to be able to move to the left side of the drawing independently of the propulsion shaft 18. Then, when the propulsion shaft 18 is at the release position (the state before the motor 10 is rotated) which is the standby position at the time of the normal release, the brake fluid pressure in the hollow portion 14a is not applied (W/C). If the pressure is 0), the piston 19 is moved to the right in the drawing by the elastic force of the seal member 22 described later, and the brake pad 11 can be separated from the brake disc 12.

Further, when the motor 10 is rotated and the propulsion shaft 18 is moved leftward from the initial position on the paper surface, even if the W/C pressure becomes zero, the moved propulsion shaft 18 moves the piston 19 rightward on the paper surface. Movement is restricted and the brake pad 11 is held in place. The clearance C1 in FIG. 2 indicates the distance between the tip of the propulsion shaft 18 and the piston 19. After the release of the EPB is completed, the propulsion shaft 18 is fixed in position with respect to the body 14.

In the wheel brake mechanism configured as described above, when the service brake 1 is operated, the brake pad 11 is braked by moving the piston 19 leftward on the paper surface based on the W/C pressure generated thereby. The disc 12 is pressed to generate a service braking force. When the EPB 2 is operated, the spur gear 15 is rotated by driving the motor 10, and the spur gear 16 and the rotary shaft 17 are accordingly rotated. Therefore, the male screw groove 17a and the female screw groove 18a are rotated. The propulsion shaft 18 is moved to the side of the brake disc 12 (to the left in the drawing) based on the meshing of. Along with that, the tip of the propulsion shaft 18 contacts the piston 19 and presses the piston 19, and the piston 19 is also moved in the same direction, so that the brake pad 11 is pressed by the brake disc 12 and an electric braking force is generated. Let Therefore, it is possible to provide a shared wheel brake mechanism that generates a braking force for both the operation of the service brake 1 and the operation of the EPB 2.

In the vehicle brake device of the first embodiment, by confirming the current detection value by the current sensor (not shown) that detects the current of the motor 10, it is possible to confirm the generation state of the electric braking force by the EPB 2 and The current detection value can be recognized.

The front-rear G sensor 25 detects G (acceleration) in the front-rear direction (travel direction) of the vehicle and transmits a detection signal to the EPB-ECU 9.

The M/C pressure sensor 26 detects the M/C pressure in the M/C 5 and sends a detection signal to the EPB-ECU 9.

The temperature sensor 28 detects the temperature of a wheel brake mechanism (for example, a brake disc) and sends a detection signal to the EPB-ECU 9.

The wheel speed sensor 29 detects the rotation speed of each wheel and sends a detection signal to the EPB-ECU 9. The wheel speed sensors 29 are actually provided one by one for each wheel, but detailed illustration and description thereof are omitted here.

The EPB-ECU 9 is composed of a well-known microcomputer including a CPU, a ROM, a RAM, an I/O, etc., and controls the rotation of the motor 10 according to a program stored in the ROM or the like to perform parking brake control. Is. Further, the EPB-ECU 9 generates an electric braking force on the left wheel by driving a left motor (motor 10) provided on the left wheel (for example, left rear wheel) side, and the right wheel (for example, right rear wheel) side. The braking control device is applied to a vehicle including an electric braking device that generates an electric braking force on a right wheel by driving a right motor (motor 10) provided in the vehicle.

The EPB-ECU 9 inputs, for example, a signal according to the operation state of an operation SW (switch) 23 provided on an instrument panel (not shown) in the vehicle compartment, and operates the motor 10 according to the operation state of the operation SW 23. To drive. Further, the EPB-ECU 9 executes lock control, release control, etc. based on the current detection value of the motor 10. Based on the control state, the EPB-ECU 9 indicates that the lock control is being performed or the wheels are locked by the lock control. It is recognized that there is a release control, and that the wheel is in the release state (EPB release state) by the release control. Then, the EPB-ECU 9 outputs a signal for performing various displays to the display lamp 24 provided on the instrument panel.

The vehicle brake device configured as described above basically performs an operation of generating a braking force on the vehicle by generating the service braking force by the service brake 1 when the vehicle is traveling. Further, when the vehicle is stopped by the service brake 1, the driver presses the operation SW 23 to operate the EPB 2 to generate the electric braking force to maintain the stopped state, and thereafter release the electric braking force. Performs the action of That is, as the operation of the service brake 1, when the driver operates the brake pedal 3 while the vehicle is traveling, the brake fluid pressure generated in the M/C 5 is transmitted to the W/C 6 to generate the service brake force. .. Further, as the operation of the EPB 2, by driving the motor 10, the piston 19 is moved, and the brake pad 11 is pressed against the brake disc 12 to generate an electric braking force to lock the wheels or to lock the brake pad 11. When the wheel is released from the brake disc 12, the electric braking force is released and the wheels are released.

Specifically, the lock/release control is used to generate or release the electric braking force. In the lock control, the EPB 2 is operated by rotating the motor 10 in the forward direction, the rotation of the motor 10 is stopped at a position where the desired electric braking force is generated by the EPB 2, and this state is maintained. As a result, a desired electric braking force is generated. In the release control, the EPB 2 is operated by rotating the motor 10 in the reverse direction, and the electric braking force generated in the EPB 2 is released.

Further, even when the vehicle is running, there are situations where it is effective to use the EPB2, for example, in an emergency, during automatic driving, when the service brake 1 fails, etc. Therefore, the EPB2 is used in those situations. Good.

Further, the EPB-ECU 9 performs the following processing in order to reduce discomfort and discomfort caused by different stop timings of the left motor and the right motor during execution of braking by the EPB 2. The cause of the difference in stop timing between the left motor and the right motor is, for example, that the left motor and the right motor have different characteristics such as rotation speed, or the clearances C1 and C2 at the start of operation are different. And so on.

When there is a drive request to the EPB 2, the EPB-ECU 9 calculates the target braking force required to maintain the vehicle stopped, and the left target current value that is the target current value for the left motor to generate the target braking force and the right target value. A right target current value, which is a target current value for the motor, is calculated. Further, the EPB-ECU 9 drives the left motor and the right motor, and the actual current value of the left motor reaches the left target current value or more, and the actual current value of the right motor reaches the right target current value or more. When one of the above is satisfied, stop control is performed to stop both the left motor and the right motor at the same time.

Before executing the stop control, the EPB-ECU 9 determines whether the condition that the actual current value of the other left motor or the right motor has reached the target current value or more is satisfied. When it is determined that the conditions are not met, execution of stop control is prohibited, and the stop current is allowed after the actual current value of the other left motor or right motor has reached the target current value or more. You may make it stop both a left motor and a right motor simultaneously.

Further, when the vehicle slips down is detected after the stop control is executed, the EPB-ECU 9 corrects the target braking force to be high, and the left motor and the right motor are controlled so as to generate the corrected target braking force. At least one of them may be driven. In that case, the EPB-ECU 9 can detect the vehicle slipping down, for example, based on the detection signal from the wheel speed sensor 29.

After the stop control is executed, the EPB-ECU 9 drives at least one of the left motor and the right motor to drive the target control if the total braking force generated at the left wheel and the right wheel is lower than the target braking force. Adjustment control for generating power may be executed. In that case, the EPB-ECU 9 prohibits the adjustment control until a predetermined vehicle operation for estimating that the occupant has exited the vehicle is detected, and executes the adjustment control when the predetermined vehicle operation is detected. Good. The predetermined vehicle operation is, for example, the shift lever being in the parking position, the ignition switch being turned off, the seat belt being released, the door being opened, and the like.

Also, the EPB-ECU 9 may execute the notification control for notifying the occupant when the adjustment control cannot be executed. The case where the adjustment control cannot be executed is, for example, the case where the adjustment control cannot be started due to a failure, or the case where the adjustment control is started but is not completed within a predetermined time and the adjustment control cannot be completed. In that case, for example, by blinking the display lamp 24, the occupant may be notified that the adjustment control cannot be executed. The cause of the adjustment control not ending within a predetermined time is, for example, a decrease in supply voltage.

Next, the overall processing by the braking control device of the first embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the overall processing by the braking control device of the first embodiment.

First, in step S1, the EPB-ECU 9 determines whether or not there is a lock control request by the EPB2. If Yes, the process proceeds to step S2, and if No, the process returns to step S1. For example, when the driver operates the operation SW 23 to operate the EPB 2 after the vehicle has stopped, the result in step S1 is Yes.

In step S2, the EPB-ECU 9 executes lock control processing. Here, FIG. 4 is a flowchart showing a process of lock control by the braking control device of the first embodiment. In step S201, the EPB-ECU 9 calculates the target braking force required to maintain the vehicle stopped.

Next, in step S202, the EPB-ECU 9 calculates the left target current value for the left motor and the right target current value for the right motor for generating the target braking force.

Next, in step S203, the EPB-ECU 9 drives the left motor and the right motor to the lock side.

Next, in step S204, the EPB-ECU 9 determines whether or not the actual current value of the left motor (left actual current value) has reached the left target current value, and if Yes, the process proceeds to step S206 and No In this case, the process proceeds to step S205.

In step S205, the EPB-ECU 9 determines whether or not the actual current value of the right motor (right actual current value) has reached the right target current value. If Yes, the process proceeds to step S206, and if No, the step is performed. Return to S204.

In step S206, the EPB-ECU 9 executes stop control for stopping both the left motor and the right motor.

Next, in step S207, the EPB-ECU 9 substitutes the left actual current value into the left reaching current value of the parameter.

Next, in step S208, the EPB-ECU 9 substitutes the right actual current value for the right reaching current value of the parameter.

Next, in step S209, the EPB-ECU 9 lights the display lamp 24 (for example, lights in red). This completes the lock control process.

Returning to FIG. 3, after step S2, in step S3, the EPB-ECU 9 executes the actual axial force estimation process. Here, FIG. 5 is a flowchart showing a process of estimating an actual axial force by the braking control device of the first embodiment.

In step S31, the EPB-ECU 9 calculates the left estimated axial force based on the left reaching current value. Specifically, for example, it is calculated using the following formula (1).
Left estimated axial force = Left reaching current value x α + β ... Equation (1)

Here, α and β are coefficients, and are determined in consideration of fixed values due to variations in the structure of each component and variable values due to deterioration of each component, environment (temperature, etc.), etc. Further, in estimating the axial force, it is preferable to adopt a lower value from the safety side in consideration of the deterioration of parts and the environment (temperature, etc.) among the widths of the estimated axial force. Not limited to. Further, the calculation may be performed based on information such as a map or a table instead of the formula.

Next, in step S32, the EPB-ECU 9 calculates the right estimated axial force based on the right reaching current value. The specific calculation method is the same as in step S31.

Next, in step S33, the EPB-ECU 9 calculates the total estimated axial force by summing the left estimated axial force and the right estimated axial force. This completes the process of estimating the actual axial force.

Returning to FIG. 3, after step S3, in step S4, the EPB-ECU 9 executes the process of calculating the required axial force. Here, FIG. 6 is a flowchart showing the process of calculating the required axial force by the braking control device of the first embodiment.

EPB-ECU9 acquires each information in step S41. The information includes, for example, vehicle weight (specification or estimation), tire diameter (specification or estimation), pad (brake pad 11) μ (friction coefficient) (design value or estimation), cylinder effective diameter (design value), road The slope (detection value or estimation).

Next, in step S42, the EPB-ECU 9 calculates the required braking force based on each information. Specifically, for example, it is calculated using the following formula (2).
Required braking force = 9.8 (gravitational acceleration) x vehicle weight x
Arcsin (tan value of road gradient) x tire diameter (2)

Next, in step S43, the EPB-ECU 9 calculates the required axial force based on the required braking force calculated in step S42. Specifically, for example, it is calculated using the following formula (3).
Required axial force = Required braking force/(2 (Number of pads) x Pad μ x Effective cylinder diameter)
...Formula (3)
This completes the process of calculating the required axial force.

Returning to FIG. 3, after step S4, in step S5, the EPB-ECU 9 executes the follow control process. Here, FIG. 7 is a flowchart showing a process of follow control by the braking control device of the first embodiment.

In step S501, the EPB-ECU 9 determines whether or not the total estimated axial force calculated in step S33 of FIG. 5 is equal to or greater than the required axial force calculated in step S43 of FIG. 6, and if Yes, the follow control ends. If No, the process proceeds to step S503.

In step S503, the EPB-ECU 9 determines whether or not adjustment control is possible. If Yes, the process proceeds to step S504, and if No, the process proceeds to step S502. For example, if the device for performing the adjustment control is out of order, the result in step S503 is No.

In step S504, the EPB-ECU 9 determines whether or not a predetermined vehicle operation for estimating that the occupant has exited the vehicle is detected. If Yes, the process proceeds to step S505, and if No, the process returns to step S504. ..

In step S505, the EPB-ECU 9 starts adjustment control.

Next, in step S506, the EPB-ECU 9 determines whether or not the total actual current value obtained by summing the left actual current value and the right actual current value is greater than or equal to the target current value, and if Yes, the process proceeds to step S509, No. In this case, the process proceeds to step S507.

In step S509, the EPB-ECU 9 ends the adjustment control and the follow control process.

In step S507, the EPB-ECU 9 determines whether or not a predetermined time has elapsed from the start of adjustment control (step S505), the process proceeds to step S508 if Yes, and the process returns to step S506 if no.

In step S508, the EPB-ECU 9 ends the adjustment control. In step S502, the EPB-ECU 9 changes the indicator lamp 24 from lighting to blinking (for example, blinking in red), and ends the follow control process.

Returning to FIG. 3, after step S5, in step S6, the EPB-ECU 9 determines whether or not the vehicle has slipped down. If Yes, the process proceeds to step S7, and if No, the process returns to step S6. ..

In step S7, the EPB-ECU 9 executes relock control processing. For convenience of description, step S6 is executed after step S5. However, in reality, after step S2 is completed, the process of step S7 in the case of Yes at step S6 and step S6 is always performed. It may be executed.

Specifically, in step S7, the EPB-ECU 9 drives at least one of the left motor and the right motor to increase the braking force so that the vehicle can be prevented from rolling down. In that case, if the actual braking force has not reached the target braking force, for example, the re-lock control process may be executed with the target braking force unchanged. If the vehicle is slipping down despite the actual braking force reaching the target braking force, the target braking force is corrected to a higher value if necessary, and the corrected target braking force is corrected. The re-lock control process may be executed based on the power.

Thus, according to the first embodiment, the left motor and the right motor are stopped at the same time in the first lock control (step S2 in FIGS. 3 and 4) at the time of executing the braking by the EPB 2 (step in FIG. 4). Since S206), there is no left-right difference in the operating sound, and it is possible to avoid a situation in which the occupant feels strange or uncomfortable.

Next, the first to fourth control examples will be described with reference to FIGS. 8 to 11. FIG. 8 is a time chart showing a first control example in the first embodiment. It is assumed that the vehicle is stopped at the start.

First, the lock control (step S2) starts at time t1. After that, at time t2, the right actual current value and the left actual current value enter the stable state after the inrush current. After that, the right actual current value starts increasing at time t3 and reaches the right target current value at time t5 (Yes in step S205 of FIG. 4). The left actual current value starts to rise at time t4, which is later than time t3, and has not yet reached the left target current value at time t5.

In this state, the left motor and the right motor stop (step S206 in FIG. 4), so the right actual current value and the left actual current value decrease to zero at time t5.

In this case, the right estimated axial force rises from time t3 to time t5, and the left estimated axial force rises from time t4 to time t5, but since the left actual current value has not reached the left target current value, The total estimated axial force, which is the sum of the estimated axial force and the left estimated axial force, has not reached the required axial force at time t5.

Then, in this first control example, it is assumed that step S504 in FIG. 7 is not provided and the adjustment control is started immediately (step S505 in FIG. 7). In this case, the left actual current value of the left motor sharply increases due to the inrush current at time t6 immediately after time t5, enters a stable state at time t7, and then increases, and reaches the left target current value at time t8. Falls to zero.

Due to this, the left estimated axial force increases from time t7 to time t8, and the total estimated axial force, which is the sum of the right estimated axial force and the left estimated axial force, exceeds the required axial force at time t8.

Further, the display lamp 24 changes from off to on at the time t5 when the first lock control is completed (step S209 in FIG. 4).

In this way, according to the first control example, first, in the first lock control (time t1 to t5), the left motor and the right motor are stopped at the time t5 at the same time. Therefore, it is possible to avoid a situation in which the occupant feels uncomfortable or uncomfortable.

Although the total estimated axial force has not reached the required axial force at time t5, the total estimated axial force can reach the required axial force by performing adjustment control immediately after that at time t6. Can be further improved.

Further, since the display by the display lamp 24 only changes from off to on and does not change to blinking indicating that the adjustment control cannot be executed, the occupant recognizes that the adjustment control cannot be executed. You can

Next, the second control example will be described. FIG. 9 is a time chart showing a second control example in the first embodiment. Since the time t1 to t5 is the same as the first control example, the description thereof is omitted.

In this second control example, it is assumed that the vehicle slips after time t5 when the first lock control is completed. In that case, when the vehicle slips down is detected at time t11 (Yes in step S6 of FIG. 3 ), relock control is executed (step S7 of FIG. 3 ). Specifically, the left actual current value of the left motor sharply rises due to the inrush current at time t11, enters a stable state at time t12, and then rises, and then decreases to zero after reaching the right target current value at time t13. To do.

As a result, the left estimated axial force increases from time t12 to time t13, and the total estimated axial force, which is the sum of the right estimated axial force and the left estimated axial force, exceeds the required axial force at time t13.

As described above, according to the second control example, first, in the first lock control (time t1 to t5), the left motor and the right motor are stopped at the time t5 at the same time. Therefore, it is possible to avoid a situation in which the occupant feels uncomfortable or uncomfortable.

Also, since the braking force is increased in response to the occurrence of the vehicle rolling down, there is no problem in terms of safety.

Next, the third control example will be described. FIG. 10 is a time chart showing a third control example in the first embodiment. Since the time t1 to t5 is the same as the first control example, the description thereof is omitted.

In this third control example, it is assumed that the adjustment control is disabled due to a failure after the time t5 when the first lock control is completed. In that case, when it is detected that the adjustment control is disabled due to a failure at time t21 (No in step S503 in FIG. 7), the display lamp 24 changes from lighting to blinking (step S502 in FIG. 7).

In this way, according to the third control example, first, in the first lock control (time t1 to t5), the left motor and the right motor are stopped at the time t5 at the same time. Therefore, it is possible to avoid a situation in which the occupant feels uncomfortable or uncomfortable.

Further, when the adjustment control cannot be performed due to a failure, the display by the display lamp 24 changes from lighting to blinking, so that the occupant can recognize that there is a situation where the adjustment control cannot be executed and take measures accordingly.

Next, the fourth control example will be described. FIG. 11 is a time chart showing a fourth control example in the first embodiment. Since the time t1 to t5 is the same as the first control example, the description thereof is omitted.

In this fourth control example, it is assumed that the adjustment control is executed after the time t5 when the first lock control is completed, but cannot be completed within a predetermined time. In that case, the left actual current value of the left motor sharply rises due to the inrush current at time t6 immediately after time t5, enters a stable state at time t7, and then rises. Since the value has not reached the value, the adjustment control ends and the value decreases to zero (Yes in step S507 in FIG. 7→step S508).

Due to this, the left estimated axial force slightly increases from time t7 to time t31, but the total estimated axial force, which is the sum of the right estimated axial force and the left estimated axial force, has not reached the required axial force at time t31.

Further, the display lamp 24 changes from off to lighting at time t5 when the first lock control is completed, and further changes from lighting to blinking at time t31 (step S502 after step S508 in FIG. 7).

In this way, according to the fourth control example, first, in the first lock control (time t1 to t5), the left motor and the right motor are stopped at the time t5 at the same time. Therefore, it is possible to avoid a situation in which the occupant feels uncomfortable or uncomfortable.

In addition, since the display by the display lamp 24 changes from lighting to blinking at time t31 in response to the adjustment control not being completed, the occupant recognizes that there is a situation in which the adjustment control cannot be executed, and responds. can do.

Also, in common with the first to fourth control examples, stopping the left motor early has the following effects. First, the next release operation time can be shortened. In addition, power consumption can be reduced. Further, the load on the caliper 13 can be reduced.

(Second embodiment)
Next, a second embodiment will be described. Descriptions of the same items as those in the first embodiment will be appropriately omitted. In the first embodiment, when one of the fact that the left actual current value reaches the left target current value and the right actual current value reaches the right target current value, both the left motor and the right motor are satisfied. It was decided to stop at the same time. In the second embodiment, both the left motor and the right motor are stopped at the same time when not only one of them but also both of them are satisfied.

FIG. 12 is a flowchart showing a lock control process by the braking control device of the second embodiment. The flowchart of FIG. 12 differs from the flowchart of FIG. 4 in that step S204 is replaced with step S204a and step S205 is deleted. Only the differences will be described below.

After step S203, in step S204a, the EPB-ECU 9 determines that the actual current value of the left motor (left actual current value) has reached the left target current value and that the actual current value of the right motor (right actual current value) is It is determined whether or not both of reaching the right target current value are satisfied. If Yes, the process proceeds to step S206, and if No, the process returns to step S204a.

FIG. 13 is a time chart showing a control example in the second embodiment. The required axial force (no variation) is a required axial force when aging deterioration of each component and individual variation are not taken into consideration, and is set as a value on the safest side, for example. The required axial force (with variations) is the required axial force in consideration of aging deterioration of individual parts and individual variations. For example, it is calculated appropriately based on each information or each condition is taken into consideration. Is set. Therefore, in general, the required axial force (with variations) has a larger value than the required axial force (without variations).

Since the time t1 to t3 is the same as that in FIG. 8, the description is omitted. The right actual current value starts increasing at time t3 and reaches the right target current value at time t5, but continues increasing thereafter. The left actual current value starts rising at time t4 and reaches the left target current value at time t42 after time t5 (Yes in step S204a of FIG. 12).

In this state, the left motor and the right motor stop (step S206 in FIG. 12), so that the right actual current value and the left actual current value decrease to zero at time t42.

In this case, the right estimated axial force increases from time t3 to time t42, the left estimated axial force increases from time t4 to time t42, and the total estimated axial force is the required axial force (no variation) and the required axial force at time t42. It has reached all of (variable). Therefore, it is not necessary to execute the adjustment control thereafter.

As described above, according to the second embodiment, in the first lock control (time t1 to t42), the left motor and the right motor are stopped at the time t42 at the same time. It is possible to avoid a situation where the occupant feels uncomfortable or uncomfortable.

When the left actual current value reaches the left target current value and the right actual current value reaches the right target current value, both the left motor and the right motor are stopped at the same time, so the total estimated axial force is required. Both axial force (no variation) and required axial force (variation) are reached, and safety can be further improved.

(Third Embodiment)
Next, a third embodiment will be described. Description of the same items as those in the second embodiment will be appropriately omitted. In the second embodiment, when both the left actual current value has reached the left target current value and the right actual current value has reached the right target current value, both the left motor and the right motor are satisfied. It was decided to stop at the same time. In the third embodiment, both the left motor and the right motor are stopped at the same time when the current total estimated axial force reaches the required axial force (with variations) even before both of them are satisfied.

FIG. 14 is a flowchart showing a lock control process by the braking control device of the third embodiment. The flowchart of FIG. 14 differs from the flowchart of FIG. 12 in that steps S211 to S213 are added. Only the differences will be described below.

If No in step S204a, in step S211, the EPB-ECU 9 estimates the current axial force. FIG. 15 is a flowchart showing the process of estimating the current axial force by the braking control device of the third embodiment.

In step S2111, the EPB-ECU 9 calculates the current left estimated axial force based on the left actual current value. Next, in step S2112, the EPB-ECU 9 calculates the current right estimated axial force based on the right actual current value. Next, in step S2113, the EPB-ECU 9 calculates the total estimated axial force by adding the current left estimated axial force and the current right estimated axial force. This completes the process of estimating the current axial force.

Returning to FIG. 14, in step S212 after step S211, the EPB-ECU 9 estimates the required axial force (variation). FIG. 16 is a flowchart showing a process of estimating a required axial force (variation) by the braking control device of the third embodiment.

In step S212, the EPB-ECU 9 acquires each information (see step S41 in FIG. 6). Next, in step S2122, the EPB-ECU 9 calculates the required braking force (variation) based on each information. Next, in step S2123, the EPB-ECU 9 calculates the required axial force (variation) based on the required braking force (variation) calculated in step S42. This completes the process of estimating the required axial force (variation).

Returning to FIG. 14, after step S212, in step S213, the EPB-ECU 9 determines whether or not the current total estimated axial force is greater than or equal to the required axial force (variation), and if Yes, the process proceeds to step S206, In No, it returns to step S204a.

By performing such processing, for example, in the example of FIG. 13, the current total estimated axial force reaches the required axial force (variation) at time 41 before time t42, and the right motor and the left motor are operated. The motors can be stopped at the same time. Therefore, it is possible to suppress the generation of an excessive axial force while generating a necessary axial force, suppress an excessive load on each component, and prolong the life of each component.

(Fourth Embodiment)
Next, a fourth embodiment will be described. Description of the same items as those in the second embodiment will be appropriately omitted. In the second embodiment, when both the left actual current value has reached the left target current value and the right actual current value has reached the right target current value, both the left motor and the right motor are satisfied. It was decided to stop at the same time. In the fourth embodiment, even before both of them are established, the EPB-ECU 9 determines whether the actual current value of the left motor reaches the left limit current value set to be larger than the left target current value or the right motor. When the actual current value reaches the right limit current value that is set larger than the right target current value, both the left motor and the right motor are stopped at the same time. The left limit current value and the right limit current value are calculated or set based on the durability and environment of each component.

FIG. 17 is a flowchart showing a lock control process by the braking control device of the fourth embodiment. The flowchart of FIG. 17 differs from the flowchart of FIG. 12 in that step S221 is added. Only the differences will be described below.

In the case of No in step S204a, in step S221 the EPB-ECU 9 determines that the actual current value of the left motor has reached the left limit current value and that the actual current value of the right motor has reached the right limit current value. It is determined whether or not at least one of them is satisfied. If Yes, the process proceeds to step S206, and if No, the process returns to step S204a.

FIG. 18 is a time chart showing a control example in the fourth embodiment. Since the time t1 to t3 is the same as that in FIG. 13, the description is omitted. The right actual current value starts increasing at time t3 and reaches the right target current value at time t5, but continues to increase thereafter and reaches the right limit current value at time t51 (Yes in step S221 of FIG. 17). ).

In this state, the left motor and the right motor stop (step S206 in FIG. 17), so the right actual current value and the left actual current value decrease to zero at time t51.

In this case, the right estimated axial force increases from time t3 to time t51, the left estimated axial force increases from time t4 to time t51, and the total estimated axial force is the required axial force (no variation) and the required axial force at time t51. It has reached all of (variable). Therefore, it is not necessary to execute the adjustment control thereafter. Note that, for example, when the total estimated axial force does not reach the required axial force (with variations), the adjustment control may be executed.

As described above, according to the fourth embodiment, in the first lock control (time t1 to t51), the left motor and the right motor are stopped at the time t51 at the same time. It is possible to avoid a situation in which the occupant feels uncomfortable or uncomfortable.

Also, when the left actual current value reaches the left limit current value or the right actual current value reaches the right limit current value, both the left motor and the right motor are stopped at the same time. It is possible to suppress deterioration and deterioration.

Note that, instead of the right limit current value and the left limit current value, a limit axial force shown in FIG. The left motor and the right motor may be stopped at the same time when the limit axial force is reached.

Also, as in the case of the third embodiment, a process of stopping the right motor and the left motor at the same time when the current total estimated axial force reaches the required axial force (with variations) may be used together.

(Fifth Embodiment)
Next, a fifth embodiment will be described. Descriptions of the same items as at least one of the first to fourth embodiments will be appropriately omitted. The process of the fifth embodiment is a combination of the processes of the first to fourth embodiments.

FIG. 19 is a flowchart showing a lock control process by the braking control device of the fifth embodiment. Steps S201 to S205 are the same as in FIG. Steps S211 to S213 are the same as in FIG. Steps S204a, S221, and S206 to 209 are the same as in FIG.

In other words, in the processing of FIG. 19, if Yes in any of Steps S204 and S205 and moves to Step S211, and if Yes in any of Steps S213, S204a, and S221, moves to Step S206. . As a result, more detailed processing can be realized.

FIG. 20 is a time chart showing a control example in the fifth embodiment. Since the time t1 to t3 is the same as that in FIG. 13, the description is omitted. The right actual current value starts rising at time t3. The left actual current value starts rising at time t4. Then, at time t41, the total estimated axial force reaches the required axial force (with variations) (Yes in step S213 in FIG. 19).

In this state, the left motor and the right motor stop (step S206 in FIG. 19), so that the right actual current value and the left actual current value decrease to zero at time t41.

In this case, the right estimated axial force increases from time t3 to time t41, the left estimated axial force increases from time t4 to time t41, and the total estimated axial force reaches the necessary axial force (variation) at time t41. There is. Therefore, it is not necessary to execute the adjustment control thereafter.

In this way, according to the fifth embodiment, in the first lock control (time t1 to t41), the left motor and the right motor are stopped at the time t41 at the same time. It is possible to avoid a situation in which the occupant feels uncomfortable or uncomfortable.

Also, when the total estimated axial force reaches the required axial force (varied), the left motor and the right motor are stopped at the same time, so the axial force becomes more appropriate without excess or deficiency.

Although the embodiments of the present invention have been illustrated above, the above embodiments are merely examples, and are not intended to limit the scope of the invention. The above-described embodiment can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. In addition, the specifications (structure, type, number, etc.) such as each configuration and shape can be appropriately changed and implemented.

For example, in the above-described first embodiment, only the left motor is driven in the adjustment control and the relock control, but the present invention is not limited to this, and only the right motor may be driven, or the left motor and the right motor may be driven. Both motors may be driven.

Also, the color when the display lamp 24 lights up or blinks is not limited to red, and may be another color such as yellow.

The notification method in the above notification control is not limited to the display by the display lamp 24, and another method such as voice or screen display may be used.

Also, the wheels subject to braking by the EPB are not limited to the rear wheels, but may be the front wheels. Further, the number of wheels of the vehicle to which the present invention is applied is not limited to four wheels, and may be six wheels or more.

Further, in step S213 of FIG. 14, the required axial force (without variation) may be used instead of the required axial force (with variation).

Claims

An electric brake device that drives the left motor provided on the left wheel side to generate electric braking force on the left wheel, and drives the right motor provided on the right wheel side to generate electric braking force on the right wheel. A braking control device applied to a vehicle including:
When there is a drive request to the electric brake device, a target braking force required to hold the vehicle is calculated, and a left target current value and a right target current value for the left motor for generating the target braking force are calculated. A right target current value that is a target current value for the motor is calculated, the left motor and the right motor are driven, and the actual current value of the left motor reaches or exceeds the left target current value, and the right Braking provided with an electric brake control unit that executes stop control for simultaneously stopping both the left motor and the right motor when one of the fact that the actual current value of the motor has reached the right target current value or more is satisfied. Control device.
Before executing the stop control, the electric brake control unit determines whether a condition that the actual current value of the other left motor or the right motor reaches or exceeds the target current value is satisfied. If it is determined that the condition is not satisfied, execution of the stop control is prohibited, and the actual current value of the other left motor or the right motor reaches the target current value or more. The braking control device according to claim 1, wherein after the control is performed, the stop control is permitted to stop both the left motor and the right motor at the same time.
The electric brake control unit, when the actual current value of the left motor reaches a left limit current value that is set larger than the left target current value, or the actual current value of the right motor is the right target current value. The braking control device according to claim 1 or 2, wherein both of the left motor and the right motor are stopped at the same time when a right limit current value that is set to be larger than the right limit current value is reached.
After the stop control is performed, the electric brake control unit corrects the target braking force so as to be high when the vehicle is slipping down, and the left motor is generated so as to generate the corrected target braking force. The braking control device according to any one of claims 1 to 3, which drives at least one of the right motor and the right motor.
After the execution of the stop control, the electric brake control unit, if the total braking force generated in the left wheel and the right wheel is lower than the target braking force, at least one of the left motor and the right motor. The braking control device according to any one of claims 1 to 4, which executes an adjustment control for driving the engine to generate the target braking force.
The electric brake control unit prohibits the adjustment control until it detects a predetermined vehicle operation for estimating that the occupant has exited the vehicle, and executes the adjustment control when the predetermined vehicle operation is detected, The braking control device according to claim 5.
The braking control device according to claim 5, wherein the electric brake control unit executes notification control to notify an occupant when the adjustment control cannot be executed.