JP2002326572A - Controller of booster and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, if a control is stopped when a brake fluid pressure is below a specified value, the brake fluid pressure decreases sharply and an operator feels uncomfortable feeling. SOLUTION: This controller of the booster comprises a function for calculating a current instruction when the brake fluid pressure decreases and a function for measuring a time elapsed after the brake fluid pressure instruction comes below the specified value. Even if the brake fluid pressure instruction comes below the specified value, the controller makes a current continuously flow for a specified time, thereby, when the brake fluid pressure Pm becomes zero, a variation in brake fluid pressure Pm becomes small and a variation in acceleration of vehicle becomes small and, accordingly, the operator becomes hard to feel the variation in acceleration i.e. a shock and can get a riding comfortableness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a booster for a vehicle brake and a method of operating the same.

[0002]

2. Description of the Related Art Japanese Patent Application Publication No. Hei 11-514607 discloses a technology related to a booster that generates a brake fluid pressure based on an input other than a brake pedal. One application of this technology is to assist the driver during panic braking. This technology supplies a current to the electromagnet at a first time interval to increase the hydraulic pressure in the master cylinder, and holds a current at a second time interval to maintain the hydraulic pressure in the master cylinder; The current is reduced to a predetermined value in the time interval of the above, the hydraulic pressure in the master cylinder is reduced, the current is maintained in the fourth time interval, the hydraulic pressure in the master cylinder is maintained, and in the fifth time interval, The current is reduced to zero to reduce the hydraulic pressure in the master cylinder to zero. The time interval for operating the booster is determined depending on the threshold value of the pressure sensor.

[0003] This technique will be applied to a case where the technique is applied to an inter-vehicle distance control vehicle that automatically accelerates and decelerates even if the driver does not operate the pedal as another application. In order to keep a safe inter-vehicle distance, the inter-vehicle distance control vehicle accelerates when the inter-vehicle distance from the preceding vehicle is long, and decelerates when the inter-vehicle distance is short. When the vehicle is decelerated, the brake fluid pressure in the master cylinder is increased by the booster to generate a braking force. At this time, consider the time during which a current is supplied to the electromagnet of the booster to generate the brake fluid pressure in the master cylinder connected and arranged after the booster.
Assuming that the value of the pressure sensor is a command in the same manner as in assisting the driver during panic braking, the control method is switched based on the brake fluid pressure from when the vehicle is decelerated to when the deceleration is stopped. Then, when the brake fluid pressure falls below the threshold value, the control of the brake fluid pressure is stopped to reduce the current to zero.

[0004]

The vehicle for controlling the distance between vehicles is
When approaching the preceding vehicle, the brake fluid pressure is increased to decelerate the own vehicle. Thereafter, when the inter-vehicle distance becomes a safe inter-vehicle distance, the brake fluid pressure is reduced to stop deceleration of the own vehicle. When the brake fluid pressure command is set to zero in order to stop the deceleration, if the brake fluid pressure command changes rapidly, a deviation occurs between the brake fluid pressure command and the brake fluid pressure. When the brake fluid pressure command becomes zero, the vehicle is generating braking force because the brake fluid pressure is still applied. Here, if the control is stopped when the command becomes equal to or less than the threshold value as in the above-described conventional technique, the brake fluid pressure decreases rapidly, the braking force is lost, and the vehicle does not suddenly decelerate. There has been a problem that a sudden change in acceleration of the vehicle causes the driver to feel uncomfortable.

[0005]

SUMMARY OF THE INVENTION The present invention is a control device for a booster for smoothly reducing the brake fluid pressure.
The first chamber (constant pressure chamber) with a movable wall in the inner chamber of the booster
And a second chamber (differential pressure chamber), a control valve for controlling a differential pressure of air pressure acting on a movable wall is provided in the valve body, and the control valve can be operated by an operation rod. A first seal seat and a second seal seat, wherein opening of the first seal seat allows ventilation to the differential pressure chamber, opening of the second seal seat allows communication between the two chambers, The control valve includes an elastic valve body cooperating with both seal seats, and the first seal seat or another seal seat cooperating with the valve body is independent of the operating rod,
In the control device of the booster, which can be operated by an electromagnet that can be controlled by the control device in the direction in which the differential chamber is ventilated, and the pressure supplied to the master cylinder connected and arranged after the booster is detected, At least a function of calculating a current command for controlling the brake fluid pressure based on the brake fluid pressure in the master cylinder and the brake fluid pressure command, and measuring a time after the brake fluid pressure command becomes equal to or less than a predetermined value. A low pressure command time measuring function is provided, and when the brake fluid pressure command becomes equal to or less than a predetermined value, current continues to flow through the booster for a predetermined time. The control device of the booster supplies a current so that the brake fluid pressure gradually decreases even if the brake fluid pressure command becomes equal to or less than a predetermined value, so that a smooth deceleration without giving the driver a sense of discomfort can be performed.

The present invention also provides a method for operating a control device of a booster for smoothly reducing a brake fluid pressure.
The first chamber (constant pressure chamber) with movable walls in the inner chamber of the booster
And a second chamber (differential pressure chamber), and a control valve for controlling a differential pressure of air pressure acting on a movable wall is provided in the valve body, and the control valve can be operated by an operation rod. A first seal seat and a second seal seat, wherein opening of the first seal seat allows ventilation to the differential pressure chamber, opening of the second seal seat allows communication between the two chambers, The control valve includes an elastic valve body cooperating with both seal seats, and the first seal seat or another seal seat cooperating with the valve body is independent of the operating rod,
In the control device of the booster, which can be operated by an electromagnet that can be controlled by the control device in the direction in which the differential chamber is ventilated, and the pressure supplied to the master cylinder connected and arranged after the booster is detected, At least a function of calculating a current command for reducing the brake fluid pressure based on the brake fluid pressure in the master cylinder and the brake fluid pressure command, and measuring a time after the brake fluid pressure command becomes equal to or less than a predetermined value. When the brake fluid pressure command becomes equal to or less than a predetermined value, current is continuously supplied to the booster for a predetermined time. The operation method of the control device of the booster is such that even if the brake fluid pressure command becomes equal to or less than a predetermined value, a current flows so that the brake fluid pressure decreases little by little. Can be done.

The present invention is also directed to a vehicle for smoothly reducing the brake fluid pressure, wherein the inner chamber of the booster is provided with a movable wall and a first chamber (constant pressure chamber) and a second chamber (differential pressure chamber). And a control valve for controlling the differential pressure of the air pressure acting on the movable wall is provided in the valve body.
A first seal seat operable by an operating rod and a second seal seat are provided, wherein opening of the first seal seat allows ventilation to the differential pressure chamber, and opening of the second seal seat corresponds to both chambers. The control valve is provided with an elastic valve body that cooperates with both seal seats, and the first seal seat or another seal seat that cooperates with the valve body is differential regardless of the operating rod. In the control device of the booster, which can be operated by an electromagnet controllable by the control device in the direction of ventilating the chamber, and the pressure supplied to the master cylinder connected and arranged after the booster is detected, A function of calculating a current command when the brake fluid pressure is reduced based on the brake fluid pressure and the brake fluid pressure command in the master cylinder, and a function of measuring a time after the brake fluid pressure command becomes a predetermined value or less. With blur If liquid pressure command is equal to or less than a predetermined value, during a predetermined time she continues to flow a current to the booster. In this vehicle, even if the brake fluid pressure command becomes equal to or less than the predetermined value, the current flows so that the brake fluid pressure gradually decreases, so that a smooth deceleration without giving the driver a feeling of strangeness can be performed.

Further, the present invention provides a function of increasing or decreasing the output based on at least an input from a brake pedal and a function of increasing or decreasing the output by electromagnetically operating a control valve in order to smoothly reduce the brake fluid pressure. A function of calculating a brake fluid pressure command, a function of calculating a corrected brake fluid pressure command for correcting the brake fluid pressure command, the brake fluid pressure command and a corrected brake fluid pressure command. A function of calculating a current command for controlling the brake fluid pressure based on the brake fluid pressure command, and when the brake fluid pressure command is larger than a predetermined value, calculating a current command based on the brake fluid pressure command, When the pressure command is equal to or less than a predetermined value, a current command is calculated based on the brake fluid pressure command and the corrected brake fluid pressure command, and the booster is supplied to the booster. The flow. The control device of the booster calculates the brake fluid pressure command so that the brake fluid pressure gradually decreases when the brake fluid pressure command falls below a predetermined value. I can do it.

The present invention also has a function of measuring the position of an obstacle in front of the host vehicle in order to prevent the vehicle from skidding due to excessive application of brake fluid pressure when traveling on a curve.
A function of generating a braking force on the own vehicle based on the measured position of the obstacle, and a function of measuring a curve radius of a road on which the own vehicle is traveling; a curve of a road on which the own vehicle is traveling; The braking force that is automatically generated in the own vehicle is limited based on the radius. By limiting the braking force that is automatically generated in the own vehicle based on the radius of the curve, it is possible to prevent the skidding from occurring even when the braking force is generated during curve running.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a control device of a booster and an operation method thereof according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a block diagram of a control device of a booster according to the present invention. Brake pedal 101 and booster 102
, A boost current command calculation 105 and a holding current command calculation 10
6, decompression current command calculation 107, and zero current command calculation 1
08, low pressure command time measurement 109, current command switching 11
0 and the current output 111. The inner chamber of the booster 102 is divided into a first chamber (constant pressure chamber) and a second chamber (differential pressure chamber) by a movable wall, and a differential pressure of air pressure acting on the movable wall in the valve body. The control valve is provided with a first seal seat operable by an operating rod and a second seal seat, and the opening of the first seal seat allows ventilation to the differential pressure chamber. And the opening of the second seal seat allows communication between the two chambers, the control valve comprising an elastic valve body cooperating with both seal seats and cooperating with the first seal seat or valve body. The other seal seat, irrespective of the operating rod, can be operated by an electromagnet controllable by the control device in the direction of venting the differential chamber, and the pressure supplied into the master cylinder connected after the booster Is detected.

The pressure increase current command calculation 105 performs feedback control based on the brake fluid pressure command Pcmd and the brake fluid pressure Pm to calculate an intermediate pressure command. Based on the intermediate pressure command, the brake fluid pressure command Pcmd is converted into a current command Icmd from the relationship between the pressure and the current measured at the time of pressure increase, which is measured in advance.

The holding current command calculation 106 obtains a current required to hold the brake fluid pressure Pm based on the brake fluid pressure Pm from a previously measured relationship between the pressure and the current, and calculates a current command Icmd. Set.

The decompression current command calculation 107 performs feedback control based on the brake fluid pressure command Pcmd and the brake fluid pressure Pm to calculate an intermediate pressure command. Based on the intermediate pressure command, the brake fluid pressure command Pcmd is converted into a current command Icmd from the relationship between the pre-measured pressure and current during pressure reduction.

The zero current command calculation 108 sets the current command Icmd to zero at a predetermined rate of change in order to cancel the control of the booster.

In the low pressure command time measurement 109, the brake fluid pressure command Pcmd is set to a predetermined value Ps (0 to 0.2 [MPa]).
The elapsed time (hereinafter referred to as low pressure command elapsed time Tl) after the following is measured.

The current command switching 110 is performed based on the brake fluid pressure command Pcmd, the brake fluid pressure Pm, and the low pressure command elapsed time Tl. One of the calculation results of the command calculation 108 is selected, and the current command Icmd of the current supplied to the booster is set.

The current output 111 supplies a current to the booster based on the current command Icmd selected by the current command switch 110.

FIG. 2 is a follow chart of the control device of the booster of the present invention. This routine is executed at predetermined time intervals. The predetermined time interval is 1 [MS] to 100 [M
S] is desirable.

First, the brake fluid pressure command Pcmd is updated in a pressure command update S101. Next, the process proceeds to the low pressure command time measurement S102, in which the low pressure command elapsed time Tl after the brake fluid pressure command Pcmd becomes equal to or less than the predetermined value Ps is measured. Next, the process proceeds to control mode update S103, where the control mode is updated based on the brake fluid pressure command Pcmd, the brake fluid pressure Pm, and the low pressure command elapsed time Tl. The control modes include a pressure increasing mode for increasing the brake fluid pressure Pm, a holding mode for keeping the pressure constant, a pressure decreasing mode for decreasing the pressure,
There are four control modes: zero hold mode, which holds at zero. Next, determination S104 of the advance control mode is performed. If the control mode is the pressure increase mode, the pressure increase current command calculation S105
To calculate the current command Icmd at the time of pressure increase. When the control mode is the holding mode, the holding current command calculation S106
To calculate the current command ICMD at the time of holding. If the control mode is the pressure reduction mode, the process proceeds to pressure reduction current command calculation S107, and the current command Icmd at the time of pressure reduction is calculated. If the control mode is the zero holding mode, the zero current command calculation S108
To calculate the current command Icmd for setting the brake fluid pressure Pm to zero. If the control mode is a control mode other than the above, the process proceeds to the current command clear S109, and the current command Icmd is set to zero in order to prevent the control. After calculating the current command Icmd according to the control mode, the process proceeds to current output processing S110, and outputs a current based on the current command Icmd.

FIG. 3 is a flowchart of the low pressure command time measurement S102. First, the brake fluid pressure command Pc
It is determined whether md is equal to or less than a predetermined value Ps. When the brake fluid pressure command Pcmd is equal to or smaller than the predetermined value Ps, the process proceeds to a low pressure command time measurement counter increment S202, and the low pressure command time measurement counter is incremented. Since this routine is executed at predetermined time intervals, it is understood that the time has elapsed each time the low pressure command time measurement counter is incremented. The low pressure command elapsed time Tl can be calculated by the product of a predetermined time interval for executing this routine and the value of the low pressure command time measurement counter. Brake fluid pressure command Pcmd
If is not equal to or less than the predetermined value Ps, the process proceeds to a low pressure command time measurement counter clear S203, and the low pressure command time measurement counter is cleared to zero. In this way, the low pressure command elapsed time Tl is maintained at zero when the brake fluid pressure command Pcmd is larger than the predetermined value Ps, and when the brake fluid pressure command Pcmd changes to be equal to or less than the predetermined value Ps, the elapsed time Tl from that time. Can be measured.

FIG. 4 is a state transition diagram of the control mode update S103. The initial state is the zero holding mode 201,
The brake fluid pressure Pm is maintained at zero. The brake fluid pressure command Pcmd increases, and Pcmd reaches a predetermined value P.
When the pressure becomes larger than 1 and becomes larger than P2 calculated based on the brake fluid pressure command Pcmd, the mode shifts to the pressure increase mode 202.

In the transition to the pressure increasing mode 202, the brake fluid pressure Pm starts to increase. When Pcmd becomes equal to or less than P3, the mode transits to the zero holding mode 201. Alternatively, when the brake fluid pressure command Pcmd becomes P3 or less and the low pressure command elapsed time Tl becomes Ts or more, the mode may be shifted to the zero holding mode 201. When Pcmd is equal to or less than P4 and the difference between the brake fluid pressure and the brake fluid pressure command (hereinafter, pressure deviation ΔP) is equal to or less than P5, the mode transits to the holding mode 203.

In the holding mode 203, the brake fluid pressure P
m is maintained at the pressure at the time of transition to this mode. Pc
When md becomes equal to or less than P8, the mode transits to the zero holding mode 201. Alternatively, when the brake fluid pressure command Pcmd becomes equal to or less than P8 and the low pressure command elapsed time Tl becomes equal to or more than Ts, the mode may be shifted to the zero holding mode 201. Pcm
When d is greater than P6 and the pressure deviation ΔP is equal to or greater than P7, a transition is made to the pressure increase mode 202. When Pcmd becomes smaller than P9 and the pressure deviation ΔP is smaller than P10, the mode shifts to the pressure reduction mode 204.

In the pressure reducing mode 204, the brake fluid pressure Pm is reduced based on the brake fluid pressure command Pcmd. When Pcmd is equal to or greater than P11 and the pressure deviation ΔP is equal to or greater than P12, the mode transits to the holding mode 203. When the brake fluid pressure command Pcmd becomes equal to or less than Ps and the low pressure command elapsed time Tl becomes equal to or more than Ts, the mode transits to the zero holding mode 201. That is, the brake fluid pressure command Pcmd decreases and the brake fluid pressure command Pcmd decreases to the predetermined value Ps.
The transition to the zero holding mode 201 does not occur only when the state becomes the following. When the low-pressure command elapsed time Tl further exceeds the predetermined value Ts therefrom, the mode shifts to the zero holding mode 201. Further, the predetermined values Ps and P3, P8 may be the same value.

FIG. 5 is a block diagram of the pressure reduction current command calculation 107. The pressure reduction control 301 performs feedback control during pressure reduction to calculate a first intermediate pressure command. Low pressure control 30
2 also performs feedback control to calculate a second intermediate pressure command. The low pressure control cancel 303 sets the second intermediate pressure command to zero. The pressure reduction control switching 304 selects the low pressure control 302 when the brake fluid pressure command Pcmd is equal to or less than the predetermined value Ps, and otherwise selects the low pressure control cancel 303. By adding the second intermediate pressure command selected by the pressure reduction control switching 304 to the first intermediate pressure command calculated by the pressure reduction control 301, the reduced pressure-current conversion map 30
Enter 5 The reduced pressure-current conversion map 305 is a map created by measuring the relationship between the pressure and the current at the time of reduced pressure in advance. The current command ICMD is retrieved from the reduced pressure-current conversion map 305 based on the input intermediate pressure command and set. That is, when the brake fluid pressure command Pcmd is larger than the predetermined value Ps, the brake fluid pressure command Pcmd is calculated by the pressure reduction control 301, and the current command Icmd is calculated based on the calculation result. Brake fluid pressure command P
If the cmd is equal to or less than the predetermined value Ps, the low pressure control 302 calculates a corrected brake fluid pressure command Ph for correcting the brake fluid pressure command Pcmd, and the low pressure control 302 calculates the brake fluid pressure command Pcmd calculated by the pressure reduction control 301. Current command Icm corrected by the calculated corrected brake fluid pressure command Ph
Calculate d. The pressure reduction control switching 304 may select the low pressure control 302 if the brake fluid pressure Pm is equal to or less than the predetermined value Ps, and may select the low pressure control cancel 303 otherwise.

FIG. 6 shows a flowchart of the decompression current command calculation S107. First, a differential term is calculated in differential term calculation S301. Next, the integral term is initialized in integral term initial setting S302. This integral term initial setting S302 is executed when the previous control mode was not the pressure reduction mode, and is not executed when the previous control mode was the pressure reduction mode. Next, an integral term is computed in integral term computation S303. Next, it is determined whether or not the brake fluid pressure command Pcmd is equal to or less than a predetermined value Ps. If the brake fluid pressure command Pcmd is equal to or less than the predetermined value Ps, a low pressure command integral term calculation S305 is performed. Calculate. If not less than the predetermined value, low pressure command integral term clear S3
At 06, the integral term when the brake fluid pressure command Pcmd is equal to or less than the predetermined value Ps is set to zero. Alternatively, it is determined whether or not the brake fluid pressure Pm is equal to or less than a predetermined value Ps by determining this determination S304.
If the value is equal to or smaller than the predetermined value Ps, the low pressure command integral term calculation S305 is selected. Otherwise, the low pressure command integral term clear S306 is selected.
May be selected. Next, proportional component calculation S30
In step 7, the calculation of the proportional component is performed. Next, integral component calculation S308
Is used to calculate the integral component. Next, differential component calculation is performed in differential component calculation S309. Next, in a control command calculation S310, a control command is calculated by adding a proportional component, an integral component, and a differential component. Next, in a current command calculation S311, a current command ICMD is retrieved and set based on the control command.

FIG. 7 shows the brake fluid pressure P
An example in the case of reducing the pressure of m will be described. Brake fluid pressure command Pc
As md decreases, the current command Icmd is calculated so that the brake fluid pressure Pm can follow it, and the brake fluid pressure Pm decreases. Brake fluid pressure command Pcm
Even if d becomes equal to or less than the predetermined value Ps at the time T1, the control is continued,
The brake fluid pressure Pm is smoothly reduced. Then, at time T2 when the brake fluid pressure command Pcmd has become equal to or less than the predetermined value Ps and the predetermined time Ts has elapsed, the brake fluid pressure Pm decreases to Pa, the control is stopped, and the brake fluid pressure Pm is returned to zero. Even if the brake fluid pressure command Pcmd becomes equal to or less than the predetermined value Ps, the control is continued for the predetermined time Ts. Therefore, when the control is stopped and the brake fluid pressure Pm is returned to zero, the amount of change in the brake fluid pressure Pm can be reduced.

FIG. 8 shows an example in which the brake fluid pressure is reduced by applying the conventional technique. Brake fluid pressure command Pcm
As d is decreased, the current command Icmd is calculated so that the brake fluid pressure Pm can follow it, and the brake fluid pressure Pm decreases. When the brake fluid pressure command Pcmd becomes equal to or less than the predetermined value Ps at time T3, the control is stopped, and the brake fluid pressure Pm is rapidly returned from the brake fluid pressure Pβ to zero.

When the brake fluid pressure Pm decreases, the braking force of the vehicle decreases, and the acceleration changes. As shown in FIG. 8, when the brake fluid pressure Pm is suddenly reduced from the brake fluid pressure Pβ to zero, the acceleration rapidly changes, and the change can be felt by the driver and feel uncomfortable. However, if the brake fluid pressure Pm becomes zero when the brake fluid pressure Pm becomes zero when the brake fluid pressure command Pcmd becomes equal to or less than the predetermined value Ps as in the present invention in FIG. In addition, the change in the brake fluid pressure Pm is small, and the change in the acceleration of the vehicle is small. If the change in the acceleration is small, the driver will not be able to feel the change, so the driver does not feel uncomfortable.

FIG. 9 shows a configuration of an inter-vehicle distance control vehicle to which the present invention is applied, which runs while maintaining a safe inter-vehicle distance with a preceding vehicle. The following distance control vehicle includes a following distance control device 401, an engine 402, a transmission 403, a brake control device 404, a booster 405, a brake pedal 406, and brake devices 407 and 408. The inter-vehicle distance control device 401 measures the inter-vehicle distance to the preceding vehicle and the preceding vehicle information on the relative speed and direction using at least one of a laser radar, a millimeter wave radar, and a camera. The target torque and the brake fluid pressure command Pcmd are calculated based on the preceding vehicle information so as to maintain a safe inter-vehicle distance. The engine 402 generates a driving torque of the vehicle based on the target torque calculated by the following distance control device 401. The transmission 403 changes the gear position based on the target torque calculated by the following distance control device 401. The brake control device 404, based on the brake fluid pressure command Pcmd calculated by the following distance control device 401,
A current is output to the booster 405 so that the brake fluid pressure Pm at 07 and 408 becomes the brake fluid pressure command Pcmd. Then, the brake control device 404 is configured as shown in FIGS.
As described above, when the brake fluid pressure command Pcmd calculated by the following distance control device 401 becomes equal to or less than the predetermined value Ps, the current continues to flow through the booster 405 for the predetermined time Ts. Further, the brake control device 404 may be integrated with the inter-vehicle distance control device 401. If the control devices are integrated into one, miniaturization becomes possible. The booster 405 electromagnetically operates the control valve based on the current output by the brake control device 404 to increase or decrease the brake fluid pressure Pm. Also, when the driver operates the brake pedal 406,
The brake fluid pressure Pm is increased or decreased based on the input of the brake pedal 406. The brake devices 407 and 408 generate a braking force for the vehicle based on the brake fluid pressure Pm.

FIG. 10 shows a vehicle to which the present invention is applied by measuring the position of a vehicle in front of the own vehicle or a stationary object (hereinafter, an obstacle, etc.) around the road and automatically accelerating and decelerating based on the position. The configuration is shown. This vehicle has a radar 501, a camera 50
2, yaw rate sensor 503, vehicle speed sensor 504, map database 505, GPS 506, steering angle sensor 50
7, curve radius calculation 508, drive braking command calculation 509,
It comprises a brake actuator 510, an engine 511, and a transmission 512. The radar 501 uses a laser radar or a millimeter-wave radar to detect the distance and relative speed to an obstacle or the like.
Measure the position in the direction. The camera 502 captures the situation in front and detects the position of an obstacle or the like in front of the host vehicle from the captured image. Further, a line indicating a boundary between the own lane and the adjacent lane is detected from the captured image. The yaw rate sensor 503 is
Measure the yaw rate of your vehicle. The vehicle speed sensor 504 is
Measure the speed of your vehicle. The map database 505 is
The road map data is stored in the memory. GPS50
6 measures the current position of the own vehicle. Steering angle sensor 50
7 measures the steering angle of the steering wheel. Curve radius calculation 5
08 calculates the curve radius of the road on which the host vehicle is traveling, based on the shape of the line indicating the boundary between the host vehicle lane and the adjacent lane detected by the camera 502. Or, the yaw rate sensor 50
The curve radius may be measured based on the yaw rate measured in Step 3 and the speed of the vehicle measured by the vehicle speed sensor 504. Alternatively, the road on which the vehicle is traveling may be extracted from the map database 505 from the current position of the vehicle measured by the GPS 506, and the curve radius may be calculated from the road shape. Alternatively, the curve radius may be calculated from the steering angle of the steering wheel. The drive braking command calculation 509 calculates a target value of a target driving force or a target driving torque for generating a driving force or a braking force in the own vehicle based on the position of an obstacle or the like detected by the radar 501 or the camera 502, Curve radius calculation 5
The target value is limited based on the curve radius calculated in step 08. The setting is made so that the absolute value of the target value decreases as the curve radius decreases. A booster or the like is used for the brake actuator 510, and a drive braking command calculation 509 is performed.
Brake actuator 5 based on the target value calculated by
10 is operated to generate a braking force on the host vehicle. Or
A drive brake command calculation 509 calculates a brake fluid pressure command Pcmd or a current command Icmd based on the target value, and a brake actuator 510 calculates a brake fluid pressure command Pc.
The braking force may be generated based on md or the current command Icmd. In this case, in the drive braking command calculation 509,
The brake fluid pressure command Pcmd or the current command Icmd is limited based on the curve radius. The engine 511 opens the throttle when generating a driving force based on the target value calculated by the driving brake command calculation 509, and closes the throttle when generating the braking force. Alternatively, the drive braking command calculation 509 may calculate an engine torque command and a throttle opening command based on the target value, and the engine 511 may generate a driving force or a braking force based on the engine torque command and the throttle opening command. . The transmission 512 sets the gear position based on the command value calculated in the drive braking command calculation 509. Further, the transmission may perform a downshift when a braking force is required.

[0033]

The brake fluid pressure Pm is maintained by continuing control for a predetermined time even if the brake fluid pressure command falls below a predetermined value.
Is zero, the change in brake fluid pressure Pm is small, and the change in vehicle acceleration is small. If the change in the acceleration is small, the driver will not be able to feel the change, so the driver does not feel uncomfortable.

When the brake fluid pressure command is equal to or less than a predetermined value, a current command is calculated based on the brake fluid pressure command and the corrected brake fluid pressure command, and a current is supplied to the booster. Since the corrected brake fluid pressure command is calculated so as to gradually decrease, the brake fluid pressure Pm
Is zero, the change in brake fluid pressure Pm is small, and the change in vehicle acceleration is small. If the change in the acceleration is small, the driver will not be able to feel the change, so the driver does not feel uncomfortable.

Also, by limiting the braking force that is automatically generated on the host vehicle based on the radius of the curve of the road on which the host vehicle is traveling, even if the brake is automatically activated while the host vehicle is running on a curve. , Can reduce skidding.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

FIG. 3 is a flowchart of low pressure command time measurement.

FIG. 4 is a state transition diagram of current command switching.

FIG. 5 is a block diagram of a pressure reduction current command calculation.

FIG. 6 is a flowchart of a pressure reduction current command calculation.

FIG. 7 is a time chart at the time of decompression according to the present invention.

FIG. 8 is a time chart at the time of pressure reduction according to a conventional method.

FIG. 9 is a configuration diagram of a vehicle that performs inter-vehicle distance control according to an embodiment of the present invention.

FIG. 10 is a configuration diagram of a vehicle that performs the adjustment side based on the position of an obstacle or the like according to the embodiment of the present invention.

[Explanation of symbols]

101, 406: brake pedal, 102: booster,
105 ... Pressure increasing current command calculation, 106 ... Holding current command calculation, 107 ... Pressure reduction current command calculation, 108 ... Zero current command calculation, 109 ... Low pressure command time measurement, 110 ... Current command switching, 111 ... Current output, 201 ... Zero Hold mode, 20
2—Pressure increase mode, 203—Holding mode, 204—Pressure reduction mode, 301—Pressure reduction control, 302—Low pressure control, 303—
Low pressure control cancellation, 304 ... pressure reduction control switching, 305 ...
Decompression pressure-current conversion map, 401 ... inter-vehicle distance control device,
402, 511: engine, 403, 512: transmission,
404 ... brake control device, 405 ... booster device, 40
7, 408 ... brake device, 501 ... radar, 502 ...
Camera, 503: Yaw rate sensor, 504: Vehicle speed sensor, 505: Map database, 506: GPS, 50
7 ... steering angle sensor, 508 ... curve radius calculation, 509 ...
Drive braking command calculation, 510 ... brake actuator,
Pcmd: brake fluid pressure command, Pm: brake fluid pressure, ΔP: pressure deviation, Tl: low pressure command elapsed time, Ph
... Compensated brake fluid pressure command.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Manaka 2520 Oita Takaba, Hitachinaka City, Ibaraki Prefecture Within the Hitachi, Ltd. Automotive Equipment Group (72) Inventor Atsushi Yokoyama 502, Kandachicho, Tsuchiura-shi, Ibaraki Co., Ltd. F-term in Hitachi Laboratories Machinery Laboratory (reference) 3D046 BB17 BB18 CC02 HH16 HH20 HH53 JJ01 JJ13 JJ24 KK07 KK08 KK09 KK11 LL05 LL08 3D048 BB25 BB33 CC08 QQ07 RR01 RR17

Claims (5)

[Claims] A booster having at least a function of increasing / decreasing an output based on an input of a brake pedal and a function of electromagnetically operating a control valve to increase / decrease an output. A function for calculating a brake fluid pressure and a current command for controlling the brake fluid pressure based on the brake fluid pressure command, and a low pressure command time measuring function for measuring a time after the brake fluid pressure command becomes a predetermined value or less. A control device for the booster, wherein when the brake fluid pressure command becomes equal to or less than a predetermined value, current is continuously supplied to the booster for a predetermined time. 2. A booster having at least a function of increasing / decreasing an output based on an input of a brake pedal and a function of electromagnetically operating a control valve to increase / decrease an output. A brake fluid pressure and a function of calculating a current command for decreasing the brake fluid pressure based on the brake fluid pressure command; and a function of measuring a time after the brake fluid pressure command becomes equal to or less than a predetermined value. When the liquid pressure command becomes equal to or less than a predetermined value, an operation method of the control device of the booster is characterized in that current is continuously supplied to the booster for a predetermined time. 3. A booster having at least a function of increasing / decreasing an output based on an input of a brake pedal and a function of electromagnetically operating a control valve to increase / decrease an output. A brake fluid pressure and a function of calculating a current command for decreasing the brake fluid pressure based on the brake fluid pressure command; and a function of measuring a time after the brake fluid pressure command becomes equal to or less than a predetermined value. A vehicle characterized in that when the fluid pressure command becomes equal to or less than a predetermined value, current is continuously supplied to the booster for a predetermined time. 4. A booster having at least a function of increasing or decreasing an output based on an input of a brake pedal and a function of electromagnetically operating a control valve to increase or decrease an output, wherein a brake fluid pressure command is calculated. A function for calculating a corrected brake fluid pressure command for correcting the brake fluid pressure command; and a current command for controlling the brake fluid pressure based on the brake fluid pressure command and the corrected brake fluid pressure command. Calculating a current command based on the brake fluid pressure command when the brake fluid pressure command is larger than a predetermined value, and calculating the brake fluid pressure command when the brake fluid pressure command is equal to or less than a predetermined value. And a current command is calculated based on the corrected brake fluid pressure command to supply a current to the booster. 5. A function for measuring a position of an obstacle in front of the own vehicle, a function for automatically generating a braking force on the own vehicle based on the measured position of the obstacle, and a road on which the own vehicle travels. A function of measuring a curve radius of the vehicle, and limiting a braking force automatically generated in the vehicle based on a curve radius of a road on which the vehicle travels.