JP4176810B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle braking control device, and more particularly to a vehicle braking control device that performs braking control by increasing / decreasing wheel cylinder pressure using a linear valve.

  As one of the braking control devices for vehicles such as automobiles, for example, as described in the following Patent Document 1 relating to one application of the applicant of the present application, anti-wheel control is performed by increasing / decreasing the wheel cylinder pressure with a differential pressure control valve. 2. Description of the Related Art A braking control device configured to perform skid control is conventionally known.

According to such a braking control device, the wheel cylinder pressure can be linearly increased / decreased by controlling the control current for the differential pressure control valve. Therefore, the pressure increasing / decreasing control valve is an open / close valve, and the open / close valve is opened / closed intermittently. Compared to the case of being controlled, it is possible to reduce abnormal noise generated during braking control and to reduce kickback.
JP-A-4-63755

  In general, control valves that linearly increase / decrease the wheel cylinder pressure, especially linear valves, change characteristics due to changes in solenoid resistance due to temperature changes, etc., compared to on / off valves. Since the change in the valve characteristic is large, the control amount for increasing / decreasing the wheel cylinder pressure in a predetermined braking control such as the initial pressure reduction of the anti-skid control may be insufficient depending on the state of the linear valve. Moreover, in order to prevent the wheel cylinder pressure increase / decrease control amount from being insufficient in the predetermined braking control, a deviation in the characteristics of the control valve must be compensated.

  However, the above-described conventional braking control device does not take into account the problems caused by the characteristic deviation of the control valve and the countermeasures, and therefore the lack of control amount for increasing / decreasing the wheel cylinder pressure during the predetermined braking control. In this respect, there is room for improvement in order to improve the braking control performance of the vehicle such as anti-skid control.

The present invention has been made in view of the above-described problems in a conventional vehicle braking control apparatus configured to linearly increase / decrease the wheel cylinder pressure, and the main problem of the present invention is that When a linear valve is used as a control valve that linearly increases or decreases the pressure, the control amount for the linear valve is changed at the start of anti-skid control as a predetermined braking control. First , the wheel cylinder pressure is surely controlled to be reduced when the anti-skid control is started .
[Means for Solving the Problems and Effects of the Invention]

According to the present invention, the main problems described above are a linear valve that increases and decreases the wheel cylinder pressure by controlling the supply and discharge of the working liquid to and from the wheel cylinder provided corresponding to each wheel, and the linear valve is controlled. have a control means for controlling the wheel cylinder pressure by the control means calculates a target control amount for the linear valve based on the braking demand of the driver when there is no need for anti-skid control, anti-skid In a vehicular braking control device that calculates a target control amount for the linear valve for anti-skid control when the control is necessary, and controls the linear valve based on the target control amount, the control means includes an actuator. the first pressure reduction during Nchisukiddo control, first, down to regardless wheel cylinder pressure to whether characteristic deviation in the linear valve has occurred Is achieved by the vehicular brake control system (configuration of claim 1), characterized in that it comprises a control amount changing means to change the target control amount to a preset correction value as a value that may sometimes reliably reduced pressure .

According to the configuration of the first aspect, when the anti-skid control is necessary, the target control amount for the linear valve for the anti-skid control is calculated, and the characteristic deviation occurs in the linear valve at the first pressure reduction of the anti-skid control. Regardless of whether or not the target control amount is changed to a preset correction value as a value that can surely reduce the wheel cylinder pressure at the time of the initial pressure reduction , the linear valve is not changed before the initial pressure reduction of the anti-skid control. The target control amount is not the target control amount, but the target control amount after the change is surely controlled, so that it is not necessary to determine whether or not the linear valve has a characteristic deviation or to compensate for the characteristic deviation of the linear valve. Regardless of whether or not characteristic deviation occurs, the wheel cylinder pressure is reliably reduced at the first pressure reduction in anti-skid control. It is possible to effectively achieve Nchisukiddo control.

According to the second aspect of the present invention, the correction value is variably set according to whether or not the wheel cylinder pressure at the time of the first pressure reduction of the anti-skid control is equal to or lower than the pressure reference value by the control amount changing means. With this configuration, the correction value is variably set depending on whether or not the deceleration of the vehicle at the first decompression of the anti-skid control is equal to or less than the deceleration reference value by the control amount changing means . Compared to the case where the target control amount is constant regardless of the wheel cylinder pressure and vehicle deceleration at the first anti-skid control pressure reduction, the reduction control amount of the wheel cylinder pressure at the first anti-skid control pressure reduction is It can be controlled optimally.
[Preferred embodiment of problem solving means]

According to one preferable aspect of the present invention, in the configuration according to any one of claims 1 to 3 , the control means controls the linear valve based on the target drive current, and changes the target drive current to achieve the target control. It is comprised so that quantity may be changed (preferred aspect 1).

According to the aspect of the present invention, in the any one of the above claims 1 to 3, the linear valve is configured provided corresponding to the respective wheels (preferred embodiment 2) .

According to another preferable aspect of the present invention, in the configuration of the preferable aspect 2 , the linear valve of each wheel is configured to include a linear valve for pressure increase and a linear valve for pressure reduction (preferred aspect). 3 ).

  In the present application, the “first pressure reduction” or “first pressure reduction” is not limited to the first pressure reduction at the time when the anti-skid control is started, and is thereafter executed before the braking control mode changes to hold or pressure increase. It includes a series of reduced pressures.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electronic control device of one embodiment of a vehicle brake control device according to the present invention. In FIG. 1, the solenoid of each valve is not shown for the sake of simplicity.

  In FIG. 1, reference numeral 10 denotes an electrically controlled hydraulic brake device. The brake device 10 includes a master cylinder 14 that pumps brake oil in response to a driver's depressing operation of the brake pedal 12. Have. A dry stroke simulator 16 is provided between the brake pedal 12 and the master cylinder 14.

  The master cylinder 14 has a first master cylinder chamber 14A and a second master cylinder chamber 14B, and these master cylinder chambers have a brake hydraulic pressure supply conduit 18 for front wheels and a brake hydraulic pressure control conduit 20 for rear wheels, respectively. Are connected at one end. Wheel cylinders 22FL and 22RL for controlling the braking force of the left front wheel and the left rear wheel are connected to the other ends of the brake hydraulic pressure control conduits 18 and 20, respectively.

  In the middle of the brake hydraulic pressure supply pipes 18 and 20, there are provided normally open type electromagnetic on / off valves (master cut valves) 24F and 24R, respectively. The electromagnetic on / off valves 24F and 24R are respectively connected to the first master cylinder chamber 14A and the second master cylinder chamber 14A. It functions as a shut-off device that controls communication between the master cylinder chamber 14B and the corresponding wheel cylinder. A wet stroke simulator 28 is connected to the brake hydraulic pressure supply conduit 20 between the master cylinder 14 and the electromagnetic opening / closing valve 24RL via a normally closed electromagnetic opening / closing valve 26.

  A reservoir 30 is connected to the master cylinder 14, and one end of a hydraulic pressure supply conduit 32 is connected to the reservoir 30. An oil pump 36 driven by an electric motor 34 is provided in the middle of the hydraulic supply conduit 32, and an accumulator 38 that accumulates high-pressure hydraulic pressure is connected to the hydraulic supply conduit 32 on the discharge side of the oil pump 36. One end of a hydraulic discharge conduit 40 is connected to the hydraulic supply conduit 32 between the reservoir 30 and the oil pump 36.

  The hydraulic pressure supply conduit 32 on the discharge side of the oil pump 36 is connected to the brake hydraulic pressure supply conduit 18 between the electromagnetic on-off valve 24F and the wheel cylinder 22FL by the hydraulic control conduit 42, and the wheel cylinder for the right front wheel is connected by the hydraulic control conduit 44. The hydraulic pressure control conduit 46 is connected to the brake hydraulic pressure supply conduit 20 between the electromagnetic on-off valve 24R and the wheel cylinder 22RL, and the hydraulic pressure control conduit 48 is connected to the wheel cylinder 22RR for the right rear wheel.

  Normally closed electromagnetic linear valves 50FL, 50FR, 50RL, and 50RR are provided in the middle of the hydraulic control conduits 42, 44, 46, and 48, respectively. The hydraulic control conduits 42, 44, 46, 48 on the side of the wheel cylinders 22FL, 22FR, 22RL, 22RR with respect to the linear valves 50FL, 50FR, 50RL, 50RR are connected to the hydraulic discharge conduit 40 by the hydraulic control conduits 52, 54, 56, 58, respectively. And normally closed electromagnetic linear valves 60FL, 60FR, 60RL, and 60RR are provided in the middle of the hydraulic control conduits 52, 54, 56, and 58, respectively.

  The linear valves 50FL, 50FR, 50RL, and 50RR function as pressure increase control valves for the wheel cylinders 22FL, 22FR, 22RL, and 22RR, respectively, and the linear valves 60FL, 60FR, 60RL, and 60RR correspond to the wheel cylinders 22FL, 22FR, 22RL, and 22RR, respectively. The linear valves function as pressure reducing control valves. Therefore, these linear valves constitute a pressure increasing / decreasing control valve for controlling supply / discharge of high pressure oil to / from each wheel cylinder from the accumulator 38 in cooperation with each other.

  The front wheel hydraulic supply conduit 18 and the right front wheel hydraulic control conduit 44 are connected to each other by a connection conduit 62F at positions close to the corresponding wheel cylinders 22FL, 22FR. A normally closed electromagnetic on-off valve 64F is provided in the middle of the connecting conduit 62F, and the electromagnetic on-off valve 64F functions as a communication control valve for controlling communication between the wheel cylinders 22FL and 22FR.

  Similarly, the hydraulic supply conduit 20 for the rear wheel and the hydraulic control conduit 48 for the right rear wheel are connected to each other by a connection conduit 62R at positions close to the corresponding wheel cylinders 22RL and 22RR. A normally closed electromagnetic on / off valve 64R is provided in the middle of the connecting conduit 62R, and the electromagnetic on / off valve 64R functions as a communication control valve for controlling the communication between the wheel cylinders 22RL and 22RR.

  As shown in FIG. 1, the brake hydraulic pressure control conduit 18 between the first master cylinder chamber 14A and the electromagnetic on-off valve 24F detects the pressure in the control conduit as the first master cylinder pressure Pm1. One pressure sensor 66 is provided. Similarly, the brake pressure control conduit 20 between the second master cylinder chamber 14B and the electromagnetic on-off valve 24R is provided with a second pressure sensor 68 for detecting the pressure in the control conduit as the second master cylinder pressure Pm2. It has been. The first and second master cylinder pressures Pm1, Pm2 are detected as values corresponding to the braking operation force of the driver with respect to the brake pedal 12.

  The brake pedal 12 is provided with a stroke sensor 70 for detecting a depression stroke St as a braking operation displacement amount of the driver, and the pressure in the hydraulic supply conduit 32 on the discharge side of the oil pump 34 is set as an accumulator pressure Pa. A pressure sensor 72 for detection is provided.

  The brake hydraulic pressure supply pipes 18 and 20 between the electromagnetic on-off valves 24F and 24R and the wheel cylinders 22FL and 22RL, respectively, are pressure sensors that detect the pressure in the corresponding pipes as the pressures Pfl and Prl in the wheel cylinders 22FL and 22RL. 74FL and 74RL are provided. Further, in the hydraulic control conduits 44 and 48 between the electromagnetic on-off valves 50FR and 50RR and the wheel cylinders 22FR and 22RR, respectively, pressure sensors for detecting the pressure in the corresponding conduits as the pressures Pfr and Prr in the wheel cylinders 22FR and 22RR. 74FR and 74RR are provided.

  The electromagnetic on-off valves 24F and 24R, the electromagnetic on-off valve 26, the motor 34, the linear valves 50FL, 50FR, 50RL, 50RR, the linear valves 60FL, 60FR, 60RL, 60RR, and the electromagnetic on-off valves 64F and 64R are electronic as described in detail later. It is controlled by the control device 76. The electronic control unit 76 includes a microcomputer 78 and a drive circuit 80.

  A drive current is supplied to each electromagnetic on-off valve, each linear valve and motor 34 from a battery not shown in FIG. 1 via a drive circuit 80, and in particular, a drive current is supplied to each electromagnetic on-off valve, each linear valve and motor 34. When not supplied, the electromagnetic on / off valves 24F and 24R and the electromagnetic on / off valves 64F and 64R are kept open, and the electromagnetic on / off valve 26, linear valves 50FL, 50FR, 50RL, 50RR, linear valves 60FL, 60FR, 60RL, 60RR are maintained. Is kept closed (non-control mode).

  Although not shown in detail in FIG. 1, the microcomputer 78 has, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output port device. These may have a general configuration in which they are connected to each other by a bidirectional common bus.

  The microcomputer 78 includes a signal indicating the first master cylinder pressure Pm1 and the second master cylinder pressure Pm2 from the pressure sensors 66 and 68, a signal indicating the depression stroke St of the brake pedal 12 from the stroke sensor 70, and a pressure sensor 72, respectively. A signal indicating the accumulator pressure Pa and a signal indicating the pressure Pi (i = fl, fr, rl, rr) in the wheel cylinders 22FL-22RR are input from the pressure sensors 74FL-74RR, respectively.

  Further, the microcomputer 78 includes a signal indicating wheel speeds Vwi (i = fl, fr, rl, rr) of the left and right front wheels and the left and right rear wheels from the wheel speed sensors 82FL to 82RR (not shown), and a longitudinal acceleration sensor 84. Further, a signal indicating the longitudinal acceleration Gx of the vehicle and an actual driving current Im energized to each linear valve from the ammeter 86 are inputted.

  The microcomputer 78 stores the braking force control flow shown in FIG. 4 as will be described later. The master cylinder pressures Pm1 and Pm2 detected by the pressure sensors 66 and 68 and the depression stroke detected by the stroke sensor 70 are stored. Based on St, the driver's braking demand is estimated, the vehicle's final target deceleration Gt is calculated based on the estimated braking demand, and the target wheel cylinder pressure (in the figure) for each wheel is calculated based on the final target deceleration Gt. Pti (i = fl, fr, rl, rr) is calculated and the linear valve 50FL to 50RR or 60FL to 60RR is calculated based on the deviation between the target wheel cylinder pressure Pti and the actual wheel cylinder pressure Pi. By calculating the target drive current It and energizing each linear valve with the drive current based on the target drive current It, the wheel cylinder pressure of each wheel is reduced. Controlled so that the target wheel cylinder pressure Pti.

  In this case, when the braking control mode is the pressure increasing mode, the microcomputer 78 controls the valve opening amounts of the linear valves 50FL, 50FR, 50RL, 50RR in accordance with the target wheel cylinder pressure Pti, and the braking control mode is the pressure reducing mode. Sometimes the valve opening amounts of the linear valves 60FL, 60FR, 60RL, 60RR are controlled according to the target wheel cylinder pressure Pti, and when the braking control mode is the holding mode, the linear valves 50FL-50RR and 60FL-60RR are kept closed. To do.

  Further, the microcomputer 78 estimates the vehicle body speed Vb in a manner known in the art based on each wheel speed Vwi as will be described later, and brake slip as a deviation between the estimated vehicle body speed Vb and the wheel speed Vwi for each wheel. The amount SLi (i = fl, fr, rl, rr) is calculated, and it is determined whether anti-skid control (referred to as ABS control in the figure) is required for each wheel based on the braking slip amount SLi, etc. When anti-skid control is required, the target wheel cylinder pressure Pti is calculated for the wheel based on the vehicle deceleration Gxb based on the longitudinal acceleration of the vehicle and the braking slip amount SLi.

  In this case, the microcomputer 78 calculates the target drive current It for the corresponding linear valve based on the deviation between the target wheel cylinder pressure Pti and the actual wheel cylinder pressure Pi for each wheel, and controls the linear valve based on the target drive current It. By doing so, the wheel cylinder pressure of each wheel is controlled to become the target wheel cylinder pressure Pti, thereby performing anti-skid control and reducing the braking slip amount.

In particular, in the illustrated embodiment, the microcomputer 78 indicates that the larger the vehicle deceleration Gxb or the braking slip amount SLi, the greater the target pressure increase / decrease gradient ΔPti (i = fl, fr, rl, rr) of the wheel cylinder pressure. 2 is calculated on the basis of the vehicle deceleration Gxb and the braking slip amount SLi, the previous target wheel cylinder pressure is Ptfi, and the cycle time of the routine shown in FIG. As described above, the target wheel cylinder pressure Pti of the wheel is calculated according to the following formula 1 at the start of the anti-skid control, and after the start of the anti-skid control, according to the following formula 2 until the anti-skid control end condition is satisfied.
Pti = Pi + ΔPtiΔT (1)
Pti = Ptfi + ΔPtiΔT (2)

  Further, as will be described in detail later, the microcomputer 78 calculates a target drive current It for the linear valve for each linear valve, and drives the corresponding linear valve based on the target drive current It.

  Further, as will be described later in detail, the microcomputer 78 sets the target drive current It for the linear to the first pressure reduction control so that the wheel cylinder pressure is not insufficiently reduced when the first pressure reduction control of the anti-skid control is performed. The value is changed to a preset value β1 or β2 according to the wheel cylinder pressure at the start, and the linear valve is driven based on the changed target drive current Ita.

  Further, the electronic control unit 76 adjusts the electric motor 34 as necessary based on the accumulator pressure Pa detected by the pressure sensor 72 so that the pressure in the accumulator is maintained at a pressure not less than a preset lower limit value and not more than an upper limit value. To drive the oil pump 36.

  Next, a braking control routine in the illustrated embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch (not shown) and is repeatedly executed at predetermined time intervals.

  First, at step 10, signals indicating the first master cylinder pressure Pm1 and the second master cylinder pressure Pm2 detected by the pressure sensors 66 and 68, respectively, are read. The target deceleration Gst is calculated based on the stroke St, the target deceleration Gpt is calculated based on the average value Pma of the first master cylinder pressure Pm1 and the second master cylinder pressure Pm2, and the vehicle is based on the target decelerations Gst and Gpt. The final target deceleration Gt is calculated, and the target wheel cylinder pressure Pti of each wheel is calculated based on the final target deceleration Gt. Although not shown in FIG. 2, when the control is started, the electromagnetic on-off valve 26 is opened, the electromagnetic on-off valves 24F, 24R, 64F, 64R are closed, and the drive of the oil pump 36 by the electric motor 34 is started. The

  Steps 30 to 160 are executed for each wheel in the order of, for example, the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel. In step 30, the anti-skid is performed in a manner known in the art. It is determined whether or not control is necessary. If a negative determination is made, the process proceeds to step 100. If an affirmative determination is made, the process proceeds to step 40.

  In step 40, the braking slip amount SLi of the wheel is calculated based on the estimated vehicle body speed Vb and the wheel speed Vwi, and based on the wheel acceleration, for example, the time differential value Vwdi of the wheel speed Vwi and the braking slip amount SLi of the wheel. The braking control mode is determined as one of the pressure increasing mode, the holding mode, and the pressure reducing mode in a manner known in the art.

  In step 50, a target increase / decrease pressure gradient ΔPti calculation map is selected and selected from a map group not shown in the figure based on the vehicle deceleration Gxb calculated based on the longitudinal acceleration Gx of the vehicle. From the map, the target pressure increase / decrease gradient ΔPti of the wheel cylinder pressure is calculated based on the braking control mode and the braking slip amount SLi of the wheel.

  In this case, when the braking control mode is the pressure increasing mode, the target pressure increasing / decreasing gradient ΔPt is calculated as a positive value as the vehicle deceleration Gxb or the wheel braking slip amount SLi increases, and the braking control mode is set to the pressure reducing mode. In some cases, the larger the vehicle deceleration Gxb or the braking slip amount SLi of the wheel, the smaller the negative value, and 0 is set when the braking control mode is the holding mode.

  In step 60, it is determined whether or not the anti-skid control is started, or whether or not the braking control mode is changed from the pressure reducing mode to the pressure increasing mode, for example. When the target wheel cylinder pressure Pti is calculated according to the above equation 1 and a negative determination is made, the target wheel cylinder pressure Pti is calculated according to the above equation 2 at step 80, and at step 90, the above step 110 or The target wheel cylinder pressure Pti calculated at 120 is stored in a memory such as a RAM.

  In step 100, the target drive current It for the linear valves 50FL to 50RR or 60FL to 60RR that require drive control is calculated based on the deviation between the target wheel cylinder pressure Pti and the actual wheel cylinder pressure Pi.

  In step 170, the pressure reduction amount setting process for the initial pressure reduction of the anti-skid control is performed in accordance with the flowchart shown in FIG. 3, and in step 180, the corresponding linear valve is driven based on the corrected target drive current Ita. When the current is applied, the linear valves 50FL to 50RR or 60FL to 60RR are controlled so that the wheel cylinder pressure Pi becomes the target wheel cylinder pressure Pti, and then the process returns to Step 10.

  Next, the decompression amount setting processing routine for the first decompression of the anti-skid control in the illustrated embodiment will be described with reference to the flowchart shown in FIG.

  First, at step 172, it is determined whether or not the current braking control is the control at the time of the first pressure reduction of the anti-skid control as in the case of the above-mentioned step 162, and when the negative determination is made, the linear valve After the corrected target drive current Ita is set to the corresponding target drive current It, the process proceeds to step 180. When an affirmative determination is made, the process proceeds to step 174.

  In step 174, it is determined whether or not the corresponding wheel cylinder pressure Pi at the start of pressure reduction in the anti-skid control is equal to or less than a reference value Po (positive constant). In step 176, the corrected target driving current Ita for the corresponding linear valve is set to the first target driving current β1 (constant), and when a negative determination is made, in step 178, the correction for the corresponding linear valve is performed. The subsequent target drive current Ita is set to the second target drive current β2 (a positive constant smaller than β1), and when step 176 or 178 is completed, the routine proceeds to step 180.

  Note that the first target drive current β1 set in step 176 is the anti-skid control in the situation where the wheel cylinder pressure Pi at the start of pressure reduction in the anti-skid control is relatively low, that is, in the situation where the road surface friction coefficient is relatively low. When the skid control is started, the wheel cylinder pressure is set to a value that can be surely reduced at the first pressure reduction regardless of whether or not the characteristic deviation occurs in the linear valve.

  The second target drive current β2 set in the above step 178 is a situation where the wheel cylinder pressure Pi at the start of the pressure reduction in the anti-skid control is relatively high, that is, in a situation where the road surface friction coefficient is relatively high. When the anti-skid control is started, the wheel cylinder pressure is set to a value that can surely reduce the pressure at the time of the first pressure reduction regardless of whether the characteristic deviation occurs in the linear valve.

  Thus, according to the illustrated embodiment, the target wheel cylinder pressure Pti of each wheel is calculated in step 20 according to the amount of braking operation by the driver, and when anti-skid control is required, an affirmative determination is made in step 30. In step 40, the braking control mode is determined as one of the pressure increasing mode, the pressure reducing mode, and the holding mode.

  In step 50, the target pressure increase / decrease gradient ΔPti of the wheel cylinder pressure is calculated based on the vehicle deceleration Gxb, the braking control mode, and the braking slip amount SLi of the wheel, and the anti-skid control is started or the braking control mode is When it has changed, an affirmative determination is made at step 60, so that at step 70, the target wheel cylinder pressure Pti is calculated according to the above equation 1, and since the start of anti-skid control, the braking control mode has not changed. Sometimes, a negative determination is made in step 60, so that in step 80, the target wheel cylinder pressure Pti is calculated according to the above equation 2.

  Further, according to the illustrated embodiment, the target drive current for the linear valve is set to the target drive current β1 or β2 that can reliably reduce the wheel cylinder pressure during the initial pressure reduction of the anti-skid control. Even if this occurs, it is possible to reliably reduce the wheel cylinder pressure when the anti-skid control is reduced for the first time, thereby reliably reducing the braking slip of the wheel.

For example, FIG. 5 shows an example of changes in the target wheel cylinder pressure Pti, the actual wheel cylinder pressure Pi, and the drive current with respect to the linear valve before and after the start of the anti-skid control in the illustrated embodiment.

  As shown in FIG. 5, if the anti-skid control is started at the time t1 and the braking control mode is changed to the holding mode at the time t4, the first pressure reduction from the time t1 to the time t4 is performed. Since the target drive current for the linear valve for pressure reduction is set to β1 or β2, the initial pressure reduction is reliably and effectively achieved, thereby reliably and effectively reducing excessive braking slip of the wheels. Can do.

  Further, according to the illustrated embodiment, since the characteristic deviation compensation of the linear valve is not performed, the braking control can be simplified, and the wheel cylinder pressure at the start of the pressure reduction of the anti-skid control can be simplified with the simple control content. Depressurization can be achieved reliably and simply. According to the illustrated embodiment, even if there is no characteristic deviation in the linear valve, the required pressure reduction amount is always achieved by always setting the target drive current to β1 or β2 at the first pressure reduction of the anti-skid control. However, since the slip amount SLi of the wheel is reduced due to the increase change in the pressure reduction amount, and the anti-skid control after the first pressure reduction is performed based on the reduced slip amount SLi, the setting of the target drive current is the wheel after the first pressure reduction. Does not adversely affect cylinder pressure increase / decrease or hold.

  In particular, according to the illustrated embodiment, the target drive current for the linear valve is set higher when the wheel cylinder pressure Pi at the start of pressure reduction in the anti-skid control is lower than when the wheel cylinder pressure Pi is high. Compared to the case where the target drive current is set to a constant value regardless of the pressure, the initial pressure reduction amount is appropriately set according to the friction coefficient of the road surface. The amount of decompression can be set appropriately.

  According to the above-described embodiment, at the start of the anti-skid control, the target wheel cylinder pressure Pti is always calculated based on the actual wheel cylinder pressure Pi, and the subsequent target wheel cylinder pressure Pti is the previous target wheel cylinder pressure Ptfi. Since the calculation is based on the base, the target wheel cylinder pressure Pti at the start of the anti-skid control can always be set lower than the actual wheel cylinder pressure Pi and to an appropriate value according to the slip state of the wheel. The pressure reduction at the start of the anti-skid control can be executed properly without delay, and the subsequent target wheel cylinder pressure Pti can be set to an appropriate value in accordance with the slip state of the wheel. The pressure Pi is appropriately and accurately controlled according to the slip state of the wheel, The Nchisukiddo control can be performed properly and effectively.

  Further, according to the above-described embodiment, even when the braking control mode changes during the anti-skid control, the target wheel cylinder pressure Pti is always calculated based on the actual wheel cylinder pressure Pi. Even when the target wheel cylinder pressure Pti changes, the target wheel cylinder pressure Pti can be set appropriately according to the slip state of the wheel, compared with the case where the target wheel cylinder pressure Pti is calculated based on the previous target wheel cylinder pressure Ptfi. Thus, the wheel cylinder pressure can be appropriately controlled without delay according to the slip state of the wheel.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in the above-described embodiment, in step 174, it is determined whether or not the wheel cylinder pressure Pi at the start of pressure reduction is equal to or lower than the reference value Po. It may be replaced with determination whether or not the speed Gxb is equal to or less than the reference value Gxbo (positive constant).

  In the above-described embodiment, the target drive currents β1 and β2 set in step 176 or 178 are constant values, but these target currents are gradually increased as time elapses from the depressurization start time. It may be modified to be reduced.

  In the above-described embodiment, the target wheel cylinder pressure Pti of each wheel is calculated as the braking operation amount of the driver or the target wheel cylinder pressure of the anti-skid control. May be computed in any manner known in the art.

1 is a schematic configuration diagram showing a hydraulic circuit and an electronic control device of a first embodiment of a vehicle brake control device according to the present invention. It is a flowchart which shows the braking control routine in embodiment. FIG. 3 is a flowchart showing a depressurization amount change routine for an initial depressurization of anti-skid control executed in step 170 of FIG. 2. It is explanatory drawing which shows an example of the change of the drive current with respect to the target wheel cylinder pressure Pti, the actual wheel cylinder pressure Pi, and the linear valve before and behind the start of anti-skid control in the case of the embodiment and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Brake device 12 ... Brake pedal 14 ... Master cylinder 22FL-22RR ... Wheel cylinder 24F, 24R, 26 ... Electromagnetic switching valve 50FL-50RR ... Linear valve 60FL-60RR ... Linear valve 64F, 64R ... Electromagnetic switching valve 66, 68 ... Pressure sensor 70 ... Stroke sensor 72, 74FL to 74RR ... Pressure sensor 76 ... Electronic control unit 82FL to 82RR ... Wheel speed sensor 84 ... Longitudinal acceleration sensor 86 ... Ammeter

Claims (3)

A linear valve that increases or decreases the wheel cylinder pressure by controlling the supply and discharge of the working liquid to and from the wheel cylinder provided corresponding to each wheel; and a control means that controls the wheel cylinder pressure by controlling the linear valve. Yes, and the control means calculates a target control amount for the linear valve based on the braking demand of the driver when there is no need for anti-skid control, wherein for anti-skid control when it is necessary for the anti-skid control calculates a target control amount for the linear valves, in the vehicle brake control apparatus for controlling the linear valve based on the target control amount, the control means for the first time decompression of a Nchisukiddo control, characteristic deviation in the linear valve previously set as a value can be reliably reduced to the first pressure reduction during the regardless wheel cylinder pressure of whether occurring Vehicle brake control apparatus characterized by comprising a control amount changing means to change the target control amount correction value that is. 2. The vehicle according to claim 1, wherein the control amount changing unit variably sets the correction value depending on whether or not the wheel cylinder pressure at the first pressure reduction of the anti-skid control is equal to or lower than a pressure reference value. Braking control device. The control amount changing means variably sets the correction value according to whether or not the vehicle deceleration at the time of the first decompression of the anti-skid control is equal to or less than a deceleration reference value. Vehicle brake control device.

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