JP2010120591A - Braking device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce odd pedal feeling for a driver when operating a brake pedal during the operation of an automatic brake. <P>SOLUTION: A master cylinder connected to a braking operation element to be operated by the driver is connected to a wheel cylinder via a brake pipe, and the brake pipe is provided with a fluid pressure control circuit capable of regulating fluid pressure of the wheel cylinder. A braking request command value is calculated by satisfying a prescribed operation condition, and the fluid pressure control circuit is controlled so that the fluid pressure of wheel cylinder may be fluid pressure according to the braking request command value. When the operation of the braking operation element is detected at this time, the braking request command value is made smaller with prescribed decreasing gradient, and the prescribed decreasing gradient is made larger as operation speed of the braking operation element in a braking direction is increased. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a braking device and a brake capable of controlling a hydraulic pressure of a wheel cylinder by connecting a master cylinder and a wheel cylinder by a brake pipe and controlling a fluid pressure control circuit interposed in the brake pipe. Regarding the method.

  As a braking device, there is a device described in Patent Document 1, for example. In this braking device, a master cylinder and a wheel cylinder are connected by a brake pipe, and a fluid pressure control circuit is interposed in the brake pipe. When a predetermined operating condition is satisfied, the automatic braking means is operated. When the automatic braking means is activated, the master cylinder and the wheel cylinder are brought into a non-communication state by closing the shutoff valve of the fluid pressure control circuit. Further, the automatic braking means controls the fluid pressure control circuit so that a predetermined hydraulic fluid pressure is generated in the wheel cylinder. As a result, an automatic braking state is established.

If the driver steps on the brake pedal while the automatic brake is operating, the automatic brake state shifts to the manual brake state by the driver. At this time, the shut-off valve is opened when the master cylinder pressure and the wheel cylinder pressure are substantially equal. This reduces the uncomfortable feeling when the brake pedal is depressed during automatic braking.
JP-A-8-198075

When the driver depresses the brake pedal and shifts to the manual brake state during the automatic brake state, the wheel cylinder is already filled with hydraulic fluid. For this reason, the brake pedal is hard. As a result, the driver feels uncomfortable with the pedal.
The present invention has been made paying attention to the above points, and it is an object to reduce a driver's uncomfortable feeling when a brake pedal (braking operator) is operated during an automatic brake operation. It is said.

  In order to solve the above problems, the present invention connects a master cylinder connected to a brake operator operated by a driver to a wheel cylinder via a brake pipe, and adjusts the hydraulic pressure of the wheel cylinder to the brake pipe. A possible fluid pressure control circuit is provided. Then, the automatic brake means calculates a braking request command value by satisfying a predetermined operating condition different from the operation of the brake operator, and the hydraulic pressure of the wheel cylinder corresponds to the liquid according to the braking request command value. The fluid pressure control circuit is controlled so as to be a pressure. At this time, when the operation of the braking operator is detected, the automatic brake means decreases the braking request command value with a predetermined decreasing gradient, and the predetermined decreasing gradient is operated in the braking direction of the braking operator. Increase as speed increases.

According to the present invention, when the driver operates the braking operation element in the braking direction, the higher the operation speed of the braking operation element in the braking direction, the less the filling of the hydraulic fluid on the wheel cylinder side. Accordingly, the hardness of the brake operator is reduced according to the operation state of the brake operator. As a result, it becomes easier to operate the braking operator.
In this way, it is possible to reduce a feeling of strangeness of operation of the brake operator with respect to the driver when the brake operator is operated during the automatic brake operation.

Next, embodiments of the present invention will be described with reference to the drawings.
(Constitution)
FIG. 1 is a configuration diagram illustrating a fluid pressure control circuit 24 and the like of the braking device.
The brake pedal 22 is connected to the master cylinder 10. The master cylinder 10 is connected to the wheel cylinders 11FL to 11RR via the brake pipe 23. The master cylinder 10 is a tandem type that creates two hydraulic pressures in accordance with the driver's pedal effort. In this embodiment, the X piping system is adopted. That is, the primary side of the master cylinder 10 is connected to the left front wheel and right rear wheel wheel cylinders 11FL, 11RR, and the secondary side of the master cylinder 10 is connected to the right front wheel / left rear wheel wheel cylinders 11FR, 11RL. In the present embodiment, an X piping method is used in which the brake system is divided into a front left wheel, a rear right wheel, a front right wheel, and a rear left wheel. However, it is not limited to this. You may employ | adopt with the front-and-back piping system divided | segmented into a front wheel and a rear wheel.

Each of the wheel cylinders 11FL to 11RR is built in a brake unit such as a disc brake or a drum brake. The disc brake generates a braking force by narrowing the disc rotor with a brake pad. The drum brake generates a braking force by pressing a brake shoe against an inner peripheral surface of a disc brake or a brake drum.
A fluid pressure control circuit 24 is interposed in the middle of the brake pipe 23. The fluid pressure control circuit 24 is a brake fluid pressure control circuit used for anti-skid control (ABS), traction control (TCS), stability control (VDC), and the like. That is, the fluid pressure control circuit 24 is configured to increase, hold, and reduce the hydraulic pressures of the wheel cylinders 11FL to 11RR regardless of the driver's brake operation.

The fluid pressure control circuit 24 will be described.
The fluid pressure control circuit 24 includes a control valve, an accumulator 14, an actuator including a pump 17 and a motor 19, and a damper chamber 18 on the primary side. The control valve includes a normally open type first gate control valve 12A, a normally open type inlet control valves 13FL and 13RR, a normally closed type outlet control valves 15FL and 15RR, and a normally open type second gate control valve 16A. .
The first gate control valve 12A is interposed in the flow path between the master cylinder 10 and the wheel cylinders 11FL and 11RR, and the flow path can be closed.

The inlet control valves 13FL and 13RR are interposed in the flow path between the first gate control valve 12A and the wheel cylinders 11FL and 11RR so that the flow path can be closed.
The accumulator 14 is interposed between the wheel cylinders 11FL and 11RR and the master cylinder 10. The accumulator 14 is constituted by, for example, a spring-type accumulator in which a compression spring is opposed to a piston of a cylinder. The configuration of the accumulator 14 is not limited to this. As long as the hydraulic fluid extracted from each of the wheel cylinders 11FL to 11RR can be temporarily stored and the pressure can be reduced efficiently, any type such as gas compression direct pressure type, piston type, metal bellows type, diaphragm type, etc. may be used. .

The outlet control valves 15FL and 15RR are interposed in a flow path between the wheel cylinders 11FL and 11RR and the accumulator 14 so that the flow path can be opened.
The second gate control valve 16A is interposed in a flow path communicating between the master cylinder 10 and the first gate control valve 12A, and between the accumulator 14 and the outlet control valves 15FL, 15RR, so that the flow path can be opened. .
The pump 17 communicates the suction side with a flow path between the accumulator 14 and the outlet control valves 15FL and 15RR. Further, the discharge side is communicated with a flow path between the first gate control valve 12A and the inlet control valves 13FL and 13RR. For example, a gear pump 17 that can ensure a substantially constant discharge amount regardless of the load pressure is used as the pump 17. The pump 17 may be a positive displacement pump such as a piston pump.

The motor 19 rotationally drives the pump 17. The motor 19 is constituted by a DC motor, for example.
The damper chamber 18 is disposed in the flow path on the discharge side of the pump 17. The damper chamber is provided to suppress pulsation of discharged hydraulic fluid and weaken pedal vibration.
The secondary side also includes a control valve, an accumulator 14, an actuator including a pump 17 and a motor 19, and a damper chamber 18, similarly to the primary side. As control valves, a first gate control valve 12B, inlet control valves 13FR and 13RL, outlet control valves 15FR and 15RL, and a second gate control valve 16B are provided.

  The first gate control valves 12A and 12B, the inlet control valves 13FL to 13RR, the outlet control valves 15FL to 15RR, and the second gate control valves 16A and 16B are electromagnetically operated by 2-port 2-position switching, single solenoid, spring offset type. It consists of a valve. The first gate control valves 12A and 12B and the inlet control valves 13FL to 13RR open the flow path at the non-excited normal position. The outlet control valves 15FL to 15RR and the second gate control valves 16A and 16B close the flow path at the non-excited normal position.

The operation of the fluid pressure control circuit 24 having the above configuration will be described. The primary side will be described as an example.
"Normal brake state (normal mode)"
The first gate control valve 12A, the inlet control valves 13FL, 13RR, the outlet control valves 15FL, 15RR, and the second gate control valve 16A are all set to a non-excited normal position. In this case, the hydraulic pressure from the master cylinder 10 is transmitted as it is to the wheel cylinders 11FL and 11RR.

“Pressure increase control (pressure increase mode)”
The first gate control valve 12A is excited and closed while the inlet control valves 13FL and 13RR and the outlet control valves 15FL and 15RR are in the non-excited normal position. Further, the second gate control valve 16A is excited and opened. Further, the pump 17 and the motor 19 are driven. As a result, the pump 17 sucks the hydraulic pressure of the master cylinder 10 through the second gate control valve 16A. Then, the discharge hydraulic pressure is transmitted to the wheel cylinders 11FL and 11RR via the inlet control valves 13FL and 13RR. As a result, the pressure is increased even when the brake pedal 22 is not operated.

"Holding control (holding mode)"
When the first gate control valve 12A, the outlet control valves 15FL, 15RR, and the second gate control valve 16A are in the non-excited normal position, the inlet control valves 13FL, 13RR are excited and closed. Alternatively, the first gate control valve 12A is excited and closed. As a result, the flow paths from the wheel cylinders 11FL and 11RR to the master cylinder 10 and the accumulator 14 are blocked, and the hydraulic pressures of the wheel cylinders 11FL and 11RR are maintained.

"Decompression control (decompression mode)"
When the first gate control valve 12A and the second gate control valve 16A are in the non-excited normal position, the inlet control valves 13FL and 13RR are excited and closed. Further, the outlet control valves 15FL and 15RR are excited and opened. As a result, the hydraulic pressures of the wheel cylinders 11FL and 11RR flow into the accumulator 14 to reduce the pressure. The hydraulic pressure flowing into the accumulator 14 is sucked by the pump 17 & motor 19 and returned to the master cylinder 10.

  The control valve and motor 19 are controlled by a command from the travel controller 20. That is, the travel controller 20 includes the first gate control valves 12A and 12B, the inlet control valves 13FL to 13RR, the outlet control valves 15FL to 15RR, the second gate control valves 16A and 16B, the pump 17 and the motor 19. By controlling the driving, the hydraulic pressures of the wheel cylinders 11FL to 11RR are increased, held, and reduced.

Here, in the above example, the first gate control valves 12A and 12B and the inlet control valves 13FL to 13RR are configured to open the flow path at the non-excited normal position. The outlet control valves 15FL to 15RR and the second gate control valves 16A and 16B are configured to close the flow path at the non-excited normal position. It is not limited to this. In short, it is only necessary to ensure the above operation by opening and closing each control valve. For example, the first gate control valves 12A and 12B and the inlet control valves 13FL to 13RR open the flow path at the excited offset position. Further, the flow path may be closed at an offset position where the outlet control valves 15FL to 15RR and the second gate control valves 16A and 16B are excited.
Here, in the fluid pressure control circuit 24, the actuator and each control valve are also referred to as a braking force control device.

FIG. 2 is a block diagram showing a schematic configuration of the control portion of the present embodiment.
As sensors, a wheel speed sensor 1, a steering angle sensor 2, a lateral G / yaw rate sensor 3, a master cylinder pressure sensor 4, and a brake switch sensor 5 are provided.
The wheel speed sensor 1 detects the wheel speed Vwi (i = FL to RR) of each wheel. The detected signal is output to the travel controller 20. As the wheel speed sensor 1, for example, an electromagnetic induction type wheel speed sensor 1 may be adopted.
The steering angle sensor 2 detects the steering angle θ of the steering wheel. The detected signal is output to the travel controller 20. As the steering angle sensor 2, an optical / non-contact type steering angle sensor 2 may be employed.

The lateral G / yaw rate sensor 3 detects the lateral GYg / yaw rate φ of the vehicle body. The detected signal is output to the travel controller 20.
The master cylinder pressure sensor 4 detects the master cylinder pressure mc_P. The detected signal is output to the travel controller 20.
The brake switch sensor 5 detects that the driver has stepped on the brake pedal 22. The detected signal is output to the travel controller 20.

Further, an object recognition unit 6, a white line recognition unit 7, a road environment recognition unit 8, and an ITS control controller 9 are provided.
The object recognition means 6 detects an object ahead of the host vehicle. The detection signal is output to the ITS controller 9. The object recognition means 6 is comprised from the laser radar arrange | positioned at the vehicle front part, for example.
The white line recognition means 7 detects the white line of the lane in which the host vehicle is traveling. The detection signal is output to the ITS controller 9. The white line recognition means 7 is comprised with a camera, for example.
The road environment recognition means 8 recognizes the road environment in which the host vehicle travels and outputs the information to the ITS control controller 9. The road environment recognizing means 8 is constituted by a navigation system, for example.

  Based on the acquired information, the ITS controller 9 determines whether or not an automatic brake operation condition different from the operation of the brake pedal is satisfied. When the automatic brake operation condition is satisfied, an ITS braking request command value to be requested is calculated based on the acquired information. Then, the calculated ITS braking request command value is output to the travel controller 20. When driving is necessary, a drive request command value is output to the travel controller 20. The operating condition is a predetermined condition that determines that the brake is necessary according to the behavior of the vehicle and the situation around the host vehicle regardless of the operation of the brake pedal.

  Examples of the control by the ITS control controller 9 include, for example, follow-up control for following the vehicle ahead of the vehicle, constant speed control for traveling at a constant vehicle speed, and traveling along the lane while preventing deviation from the white line. Lane keep control and the like. In the case of the follow-up control, it is determined whether braking is necessary based on the inter-vehicle distance and the relative speed between the preceding vehicle and the host vehicle. If it is determined that braking is necessary, an ITS braking request command value for setting the inter-vehicle distance to a predetermined distance is calculated based on the inter-vehicle distance and the relative speed.

Processing of the ITS control controller 9 will be described.
First, in step S300, it is determined whether or not an automatic brake operating condition is satisfied. If the operating condition is satisfied, the process proceeds to step S310. If the operating condition is not satisfied, the process proceeds to step S390.
In step S390, the ITS braking request flag ITS_FLG is turned OFF to return.
In step S310, the ITS braking request flag ITS_FLG is turned ON, and the process proceeds to step S320.

In step S320, it is determined whether or not the driver has operated the brake pedal 22. That is, it is determined whether or not the brake switch is ON. If it is determined that the brake switch is ON, the process proceeds to step S330. On the other hand, if it is determined that the brake switch is OFF, the process proceeds to step S380.
In step S330, a decreasing gradient is calculated.
The brake pedal depression speed dmc_P is calculated. Then, based on FIG. 4, a decreasing gradient ΔPmc_ITS corresponding to the depression speed dmc_P of the brake pedal 22 is calculated. The decreasing gradient increases as the depression speed (dmc_P) of the brake pedal 22 increases.

Next, in step S340, a first decrease gradient correction amount ΔPmc_ITS_s1 is calculated.
That is, based on FIG. 5, the first decrease gradient correction amount ΔPmc_ITS_s1 corresponding to the magnitude of the ITS braking request command value (mc_ITS) is calculated. The first decrease gradient correction amount ΔPmc_ITS_s1 becomes a larger value as the ITS braking request command value (mc_ITS) is larger. The calculation of the first decreasing gradient correction amount ΔPmc_ITS_s1 may be set only when it is detected that the brake switch is turned on.

Next, in step S350, the second decrease gradient correction amount ΔPmc_ITS_s2 is calculated.
That is, based on FIG. 6, the second decrease gradient correction amount ΔPmc_ITS_s2 corresponding to the amount of change (Δmc_ITS) in the ITS braking request command value is calculated. The second decrease gradient correction amount ΔPmc_ITS_s2 becomes a larger value as the change amount (Δmc_ITS) of the ITS braking request command value is larger.
Next, in step S360, a final decrease gradient ΔPmc_ITS0 is obtained based on the following equation.
ΔPmc_ITS0 = ΔPmc_ITS + ΔPmc_ITS_s1
-ΔPmc_ITS_s2

Next, in step S370, an ITS braking request command value is calculated.
That is, as shown in the following equation, the final decrease gradient ΔPmc_ITS0 is subtracted from the previous ITS braking request command value mc_ITS (n−1) in the control cycle to calculate the ITS braking request command value mc_ITS. Then return.
mc_ITS = mc_ITS (n−1) −ΔPmc_ITS0
Here, (n-1) indicates a value one cycle before.

On the other hand, in step S380, the ITS braking request command value mc_ITS is calculated from the acquired information (vehicle information, information on the surroundings of the vehicle, etc.), and the process returns.
Next, the traveling controller 20 calculates a braking request command value and a drive request command value based on the input signal. The braking request command value is output to a braking force control device (each control valve and a motor that drives the pump). The drive request command is output to the engine output control device 21. That is, the travel control process is executed based on the detection signals from the sensors, and the engine output control device and the braking force control device are driven to perform automatic deceleration according to the travel state of the vehicle.

Next, the braking control process related to the present invention in the process of the travel controller 20 will be described with reference to FIG. This control process is executed as a timer interrupt process every predetermined time (for example, 10 msec).
First, in step S10, data from various sensors (each wheel speed Vwi (i = FL to RR), steering angle θ, lateral G / yaw rate Yg / φ, master cylinder pressure mc_P, brake switch BS) are read.

Next, in step S20, information from the ITS controller 9 is read. Information acquired from the ITS control controller 9 is an ITS braking request command value mc_ITS and an ITS braking request flag ITS-FLG. The ITS braking request flag ITS-FLG is ON when automatic control is operating, and is OFF when automatic braking is not operating.
Next, at step S30, the ITS braking request command value mc_ITS and the master cylinder pressure mc_P (target braking amount) are selected high as shown in the following equation, and the larger one is set as the target hydraulic pressure (corresponding to the master) Pm. To do. The target hydraulic pressure Pm is a target value for deceleration control. The master cylinder pressure mc_P (target braking amount) is a target braking amount corresponding to the operation amount of the brake pedal.
(I) When ITS braking request command value mc_ITS ≧ master cylinder pressure mc_P
Target hydraulic pressure Pm = ITS braking request command value mc_ITS.
(Ii) Other than the above (ITS braking request command value mc_ITS <master cylinder pressure mc_P)
Target hydraulic pressure Pm = master cylinder pressure mc_P.
Here, by performing the select high, it is possible to smoothly shift to the braking force by the manual brake to the driver.

Next, in step S40, it is determined whether or not the ITS braking request flag ITS-FLG is ON. If the ITS braking request flag ITS-FLG is ON, the automatic braking is in operation and the process proceeds to step S50.
On the other hand, when the ITS braking request flag ITS-FLG is OFF, it is determined that automatic braking is not in operation and the process proceeds to step S45.
In step S45, the control valves are set to the “normal brake state” and returned.

  On the other hand, in step S50, it is determined whether or not the driver has operated the brake pedal 22. That is, it is determined whether or not the brake switch is ON. If it is determined that the brake switch is ON, the first gate control valve is set to be changed to the open state, and the process proceeds to step S70. At this time, when the brake switch is detected to be ON, the exciting current to the first gate control valve is gradually reduced in order to return the first gate control valve to open. That is, the excitation current is decreased by a predetermined current for each control cycle, and the non-excitation state is restored.

On the other hand, if it is determined in step S50 that the brake switch is OFF, the process proceeds to step S60.
In step S60, the pump 17 & motor 19 and each control valve are controlled according to the ITS braking request command value mc_ITS. For example, based on the change in the ITS braking request command value mc_ITS, one of the pressure increasing mode, the holding mode, and the pressure reducing mode is determined, and each control valve is set to the corresponding mode position. That is, if the change in the ITS braking request command value mc_ITS is in the increasing direction, the pressure increasing mode is selected. If the change in the ITS braking request command value mc_ITS is in a decreasing direction, the decompression mode is selected. If the change in the ITS braking request command value mc_ITS is almost zero, the holding mode is selected.

Further, the motor rotational speed Nm corresponding to the change in the ITS braking request command value mc_ITS is calculated, and the motor 19 is set in the rotational drive control state so as to become the motor rotational speed Nm. Then return.
On the other hand, in step S70, it is determined whether or not the target hydraulic pressure Pm is an ITS braking request command value mc_ITS. If the target hydraulic pressure Pm is not the ITS braking request command value mc_ITS, that is, the master cylinder pressure mc_P, the process proceeds to step S75. On the other hand, when the target hydraulic pressure Pm is the ITS braking request command value mc_ITS, the process proceeds to step S80.

In step S75, the control valves are set to the “normal brake state” and returned.
On the other hand, in step S80, the pump 17 & motor 19 and each control valve are controlled according to the ITS braking request command value mc_ITS. For example, based on a change in the ITS braking request command value mc_ITS, any one of the pressure increasing mode, the holding mode, and the pressure reducing mode is determined, and each valve is set to the corresponding mode position. Further, the pump 17 and the motor 19 are driven at a motor rotational speed corresponding to a change in the ITS braking request command value mc_ITS. Then return.

(Operation / Action)
When the automatic brake is operating, the wheel cylinder is already filled with hydraulic fluid. When the driver depresses the brake pedal 22 in this state, the brake pedal 22 becomes hard or the brake pedal 22 becomes difficult to depress, and the pedal feels strange.
On the other hand, in this embodiment, when the driver detects the operation of the brake pedal 22, the ITS braking request command value mc_ITS is reduced. This relieves the filling of the hydraulic fluid on the wheel cylinder side and suppresses the pedal discomfort.
At this time, the decreasing gradient ΔPmc_ITS of the ITS braking request command value mc_ITS is changed depending on the depression speed of the brake pedal of the driver.

That is, when the depression speed is high, the decrease gradient ΔPmc_ITS of the ITS braking request command value mc_ITS is increased. This further suppresses the brake pedal hardness of the driver. Further, since the stepping speed is high, it is possible to immediately generate hydraulic pressure by manual braking. As a result, the feeling of missing deceleration due to sudden decompression is also suppressed.
On the other hand, when the stepping-on speed is low, the decreasing gradient ΔPmc_ITS of the ITS braking request command value mc_ITS is relatively reduced. This reduces the feeling of deceleration loss due to sudden decompression. Here, when the stepping speed of the driver is low, the brake pedal hardness is smaller than when the stepping speed is high.

  Further, when the driver operates the brake pedal 22 when the ITS braking request command value mc_ITS is large, the hydraulic fluid pressure on the wheel cylinder side is higher than when the ITS braking request command value mc_ITS is small. For this reason, the hardness of the brake pedal 22 feels stronger. On the other hand, the decrease gradient ΔPmc_ITS of the ITS braking request command value mc_ITS is corrected according to the magnitude of the ITS braking request command value mc_ITS, so that the hardness of the brake pedal 22 can be set according to the operation state of the brake pedal 22. Suppress.

  When the ITS braking request command value mc_ITS is in the increasing direction, the motor 19 & pump 17 is operated to suck in the hydraulic fluid from the master cylinder 10 side, and pump the hydraulic fluid to the wheel cylinder side. In this state, when the driver operates the brake pedal 22 in this state, the depression direction of the brake pedal 22 is a sucking direction, and it is difficult to feel the hardness of the brake pedal 22. Based on this, when the changing speed of the ITS braking request command value mc_ITS is large in the increasing direction, the decrease gradient ΔPmc_ITS of the ITS braking request command value mc_ITS is corrected in the small direction. As a result, it is possible to suppress changes in the hardness and deceleration of the brake pedal 22.

FIG. 8 shows an example of the time chart.
In this example, the brake pedal 22 is operated while the ITS braking request command value mc_ITS is constant. By detecting the operation of the brake pedal 22, a transition to the manual brake state is made. In order to shift to the manual brake state, the ITS braking request command value mc_ITS is decreased by a predetermined decrease gradient ΔPmc_ITS.
In this embodiment, the ITS braking request command value mc_ITS and the master cylinder pressure mc_P are selected high, and the larger one is set as the target hydraulic pressure (corresponding to the master) Pm.
Here, the brake pedal 22 constitutes a braking operator. The ITS controller 9 constitutes automatic braking amount calculation means. The travel controller 20 constitutes a hydraulic pressure control means. Steps S330 to S370 constitute a decreasing gradient adjusting means. The ITS control controller 9, the travel control controller 20, and steps S330 to S370 constitute automatic brake means.

(Effect of this embodiment)
(1) The automatic braking amount calculation means operates when a predetermined operating condition different from the operation of the braking operator is satisfied, and calculates a braking request command value. Further, when detecting the operation of the braking operator, the automatic braking amount calculating means decreases the braking request command value with a predetermined decreasing gradient as an automatic braking end process. The hydraulic pressure control means controls the fluid pressure control circuit so that the hydraulic pressure of the wheel cylinder becomes a hydraulic pressure corresponding to the braking request command value. At this time, the decreasing gradient adjusting means increases the predetermined decreasing gradient as the operating speed of the braking operator in the braking direction increases.

  When the driver operates the braking operation element in the braking direction, the higher the operation speed in the braking direction of the braking operation element, the more the filling of the hydraulic fluid on the wheel cylinder side is further eased. As a result, the hardness of the brake operator is eased according to the operation state of the brake operator, and the brake operator is easily operated. That is, it is possible to reduce a feeling of strange operation of the brake operator with respect to the driver when the brake operator is operated during the automatic brake operation.

That is, when the driver depresses the brake pedal 22, the braking request command value mc_ITS is gradually reduced with a predetermined decreasing gradient. Thereby, the filling of the hydraulic fluid on the wheel cylinder side is eased, and the brake pedal hardness of the driver is suppressed.
At this time, when the stepping-in speed is high, the filling gradient of the hydraulic fluid on the wheel cylinder side is further eased by increasing the decreasing gradient ΔPmc_ITS. At this time, the hydraulic pressure by the manual brake can be generated immediately, and the feeling of deceleration loss (tradeoff) due to sudden pressure reduction can be suppressed.
On the other hand, when the stepping-on speed is low, the decrease in the ITS braking request command value (ΔPmc_ITS) can be reduced to reduce the feeling of missing deceleration due to sudden pressure reduction. Note that when the driver's stepping speed is low, the brake pedal hardness is less felt than when the driver's stepping speed is high.

(2) The decreasing gradient adjusting means corrects the predetermined decreasing gradient in a direction of increasing as the braking request command value when the operation of the braking operator is detected is increased. That is, as the ITS braking request command value (mc_ITS) is larger, the decreasing gradient (ΔPmc_ITS) of the ITS braking request command value is corrected in a larger direction.
When the ITS braking request command value (mc_ITS) is large, when the driver operates the braking operator (brake pedal), the hydraulic fluid pressure on the wheel cylinder side is smaller than when the ITS braking request command value (mc_ITS) is small. high. From this, the driver feels the hardness of the brake pedal more.
On the other hand, the hardness of the brake pedal can be further suppressed by correcting the decrease gradient (ΔPmc_ITS) of the ITS braking request command value in the larger direction.

(3) When the amount of change in the braking request command value is in the pressure increasing direction, the decreasing gradient adjusting means corrects the predetermined decreasing gradient in a decreasing direction. That is, as the ITS braking request change amount (Δmc_ITS) increases in the increasing direction, the decreasing gradient (ΔPmc_ITS) of the ITS braking request command value is corrected in a smaller direction.
When the ITS braking request command value is in the increasing direction, the motor and pump are operated to suck in the hydraulic fluid from the master cylinder side, and pump the hydraulic fluid to the wheel cylinder side. At that time, if the driver depresses the brake pedal, the brake pedal is sucked in and the hardness of the brake pedal is hardly felt.
For this reason, when the ITS braking request command value change amount (Δmc_ITS) is large in the increasing direction, the decreasing slope (ΔPmc_ITS) of the ITS braking request command value is corrected in the small direction. As a result, it is possible to suppress changes in the hardness and deceleration of the brake pedal.

(4) When the target braking amount according to the operation amount of the brake operator is larger than the braking request command value, the hydraulic pressure control means controls the pump and the control so that the hydraulic pressure becomes the hydraulic pressure according to the target braking amount. Adjust the valve. That is, the target braking amount and the braking request command value according to the operation amount of the braking operator are selected high.
As a result, it is possible to smoothly shift to the braking force by the manual brake operated by the driver.

(Modification)
(1) In the above embodiment, the decreasing gradient is continuously determined according to the brake pedal depression speed (dmc_P) of the driver. Instead, there is a possibility that the deceleration fluctuation may occur due to the fluctuation of the decreasing gradient caused by the fluctuation of the brake pedal depression speed (dmc_P) of the driver. In view of this, a multi-step decreasing gradient map such as two or three steps is determined in advance, and the decreasing gradient is determined by switching the predetermined map in accordance with the brake pedal depression speed (dmc_P) of the driver. Also good.
For example, as shown in FIG. 9, the motor rotational speed correction value ΔNm may be set so as to increase in a plurality of steps according to the stepping speed (dmc_P).

It is a figure explaining the hydraulic control circuit concerning an embodiment based on the present invention. It is a schematic block diagram which shows the structure of the control which concerns on embodiment based on this invention. It is a figure explaining the outline | summary of a process of the ITS control controller which concerns on embodiment based on this invention. It is a figure which shows the example of the decreasing gradient with respect to the depression speed. It is a figure which shows the example of a 1st decreasing gradient correction value. It is a figure which shows the example of a 2nd decreasing gradient correction value. It is a figure explaining the process of the traveling control controller which concerns on embodiment based on this invention. It is a figure which shows the example of a time chart which concerns on embodiment based on this invention. It is a figure explaining an example of motor rotation speed correction value (DELTA) Nm.

Explanation of symbols

9 ITS control controller (automatic braking amount calculation means)
10 Master cylinders 11FL to 11RR Wheel cylinder 17 Pump 19 Motor 20 Travel controller (hydraulic pressure control means)
22 Brake pedal (braking operator)
23 Brake piping 24 Fluid pressure control circuit dmc_P Depression speed ITS_FLG Braking request flag mc_ITS Braking request command value mc_P Master cylinder pressure Pm Target hydraulic pressure ΔPmc_ITS Decreasing gradient ΔPmc_ITS_s1 First decreasing gradient correction amount ΔPmc_ITS_s2 Second decreasing gradient correction amount

Claims (5)

The brake operator operated by the driver, the master cylinder connected to the brake operator, the brake pipe connecting the master cylinder and the wheel cylinder, and the hydraulic pressure of the wheel cylinder can be adjusted via the brake pipe. A fluid pressure control circuit,
When a predetermined operating condition different from the operation of the brake operator is satisfied, the hydraulic pressure control circuit is controlled to control the hydraulic pressure of the wheel cylinder, and when the operation of the brake operator is detected, automatic braking is performed. Automatic braking means for performing the end processing of,
The automatic braking means is
When a predetermined operation condition different from the operation of the brake operator is satisfied, the operation is performed to calculate a brake request command value, and when the operation of the brake operator is detected, the brake request command is executed with a predetermined decreasing gradient as the end process. Automatic braking amount calculating means for reducing the value;
Hydraulic pressure control means for controlling the fluid pressure control circuit so that the hydraulic pressure of the wheel cylinder becomes a hydraulic pressure corresponding to the braking request command value;
A decreasing gradient adjusting means for increasing the predetermined decreasing gradient as the operating speed of the braking operator in the braking direction increases.
A braking device comprising:   2. The braking according to claim 1, wherein the decreasing gradient adjusting unit corrects the predetermined decreasing gradient in a direction of increasing as the braking request command value when the operation of the braking operator is detected is increased. apparatus.   3. The decreasing gradient adjusting means corrects the predetermined decreasing gradient in a decreasing direction when the amount of change in the braking request command value is in a pressure increasing direction. Braking device.   The fluid pressure control means is configured to control the fluid pressure control circuit so that the fluid pressure corresponds to the target braking amount when the target braking amount corresponding to the operation amount of the braking operator is larger than the braking request command value. The braking device according to any one of claims 1 to 3, wherein the braking device is controlled. A master cylinder connected to a brake operator operated by a driver is connected to a wheel cylinder via a brake pipe, and a fluid pressure control circuit capable of adjusting the hydraulic pressure of the wheel cylinder is provided in the brake pipe.
The brake request command value is calculated by satisfying a predetermined operating condition different from the operation of the brake operator, and the fluid pressure of the wheel cylinder becomes a fluid pressure corresponding to the brake request command value. While controlling the pressure control circuit, if the operation of the braking operator is detected, the braking request command value is decreased with a predetermined decreasing gradient,
The braking method, wherein the predetermined decreasing gradient is increased as the operating speed of the braking operator in the braking direction increases.

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