JP2002347596A - Brake controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a wheel cylinder pressure exactly by means of a linear valve in spite of characteristic deviation of a linear valve. SOLUTION: A desired wheel cylinder pressure Pti of each wheel is calculated according to a brake operating quantity of a driver (S200), a desired wheel cylinder pressure Pti for reducing a skid is calculated, when an anti-skid control is necessary (S30 to 80), a desired drive current It for the linear valve is calculated based on the deviation from the desired wheel cylinder pressure Pti and the actual wheel cylinder pressure Pi (S100), the ratio Ro of the desired drive current It to the actual drive current Im is calculated for N cycles, these mean values are calculated as a correction factor Rr for compensating the characteristic deviation, and the linear valve is controlled, based on the desired drive current Ita after the correction (S130, 160).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake control device, and more particularly, to a vehicle brake control device that performs a brake control by controlling a wheel cylinder pressure to increase or decrease with a linear valve.

[0002]

2. Description of the Related Art As one of braking control devices for vehicles such as automobiles, for example, Japanese Patent Application Laid-open No.
As described in JP-B-63755, there has been conventionally known a brake control device configured to perform anti-skid control by controlling increase and decrease of a wheel cylinder pressure by a differential pressure control valve.

According to such a brake control device, the wheel cylinder pressure can be linearly increased or decreased by controlling the control current to the differential pressure control valve. Therefore, the pressure increase / decrease control valve is an open / close valve and the open / close valve is intermittent. As compared with the case where the opening / closing control is performed, the abnormal noise generated during the braking control can be reduced, and the kickback can be reduced.

[0004]

Generally, a control valve for linearly increasing and decreasing the wheel cylinder pressure, particularly a linear valve, has a characteristic change due to a temperature change or the like, for example, a command drive current to the control valve is smaller than an on-off valve. Due to the large change in the valve opening characteristics, deviations in the characteristics of the control valve must be compensated for in order to accurately control the wheel cylinder pressure. However, in the above-mentioned conventional braking control device, compensation for the characteristic deviation of the control valve is not taken into consideration, and therefore, the wheel cylinder pressure is accurately controlled to improve the braking control performance of the vehicle such as anti-skid control. To do so, there is room for improvement in this regard.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in a conventional vehicle braking control device configured to linearly increase and decrease the wheel cylinder pressure. When a linear valve is used as a control valve that linearly increases and decreases the wheel cylinder pressure, by compensating for the characteristic deviation of the linear valve,
It is an object of the present invention to accurately control the wheel cylinder pressure by the linear valve regardless of the characteristic deviation of the linear valve.

[0006]

According to the present invention, a main object of the present invention is to control the supply and discharge of hydraulic fluid to and from a wheel cylinder provided for each wheel. A linear valve for increasing / decreasing a wheel cylinder pressure according to a vehicle, and control means for controlling a wheel cylinder pressure by controlling a drive current to the linear valve according to a state of the vehicle. Compensation means for compensating for a characteristic deviation of the linear valve based on a deviation between a target drive current and an actual drive current for the valve, wherein the compensation means compensates by the compensation means when the deviation is outside a predetermined allowable range. This is achieved by a vehicle braking control device characterized by having a contribution degree reducing means for reducing the contribution degree of the deviation to the vehicle.

According to the configuration of the first aspect, the characteristic deviation of the linear valve is compensated based on the deviation between the target driving current and the actual driving current for the linear valve. Can be accurately controlled, and when the deviation between the target drive current and the actual drive current is outside a predetermined allowable range, the degree of contribution of the deviation to the compensation of the characteristic deviation is reduced. It is reliably prevented that the characteristic deviation of the linear valve is inappropriately compensated based on the resulting inappropriate deviation.

Further, according to the present invention, in order to effectively achieve the above-mentioned main object, in the above-mentioned configuration of the first aspect, the compensating means is configured to change the linear valve in accordance with the estimated temperature change of the linear valve. It is configured to variably set a predetermined allowable range (the configuration of claim 2).

According to the second aspect of the present invention, the predetermined allowable range is variably set in accordance with the estimated temperature change of the linear valve. Compensation for the characteristic deviation is performed accurately.

According to the present invention, in order to effectively achieve the above-mentioned main object, in the configuration of the first or second aspect, the compensating means calculates the deviation at predetermined time intervals,
The apparatus is configured to compensate for a characteristic deviation of the linear valve by correcting a target drive current based on an average value of the plurality of deviations.

According to the third aspect of the present invention, the deviation between the target drive current and the actual drive current is calculated every predetermined time, and the target drive current is corrected based on the average value of the plurality of deviations. Since the characteristic deviation of the linear valve is compensated for, the characteristic deviation of the linear valve is compensated more appropriately than when the target driving current is corrected based on one deviation between the target driving current and the actual driving current. Will be

Further, according to the present invention, in order to effectively achieve the above-mentioned main object, in the above-mentioned constitutions of claims 1 to 4, the contribution degree reducing means is arranged so that the deviation is out of a predetermined allowable range. In some cases, the degree of contribution of the deviation to the compensation by the compensation means is reduced to zero (the configuration of claim 4).

According to the fourth aspect of the invention, when the deviation between the target drive current and the actual drive current is out of the predetermined allowable range, the contribution of the deviation to the compensation for the characteristic deviation is reduced to zero. Improper compensation for the characteristic deviation of the linear valve based on the deviation outside the predetermined allowable range is reliably prevented.

[0014]

According to a preferred aspect of the present invention, in the configuration of the first aspect, the deviation between the target drive current and the actual drive current is a ratio of the target drive current to the actual drive current. It is configured as such (preferred embodiment 1).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 1, the compensating means calculates a ratio of the target drive current to the actual drive current at predetermined time intervals, and The average value of the ratio is calculated as a compensation coefficient,
The target drive current is configured to be corrected by the compensation coefficient (preferred mode 2).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned preferred embodiment 2, the contribution degree reducing means includes a step of setting the ratio of the target drive current to the actual drive current outside a predetermined allowable range. By calculating the average value excluding the ratio, the degree of contribution of the ratio to the compensation for the characteristic deviation is reduced to zero (preferred mode 3).

According to another preferred embodiment of the present invention, the above claims 1 to 4 or the above preferred embodiments 1 to 3 are provided.
In the above configuration, the linear valves are provided corresponding to the respective wheels, and the compensation for the characteristic deviation is performed for all the linear valves (preferred mode 4).

According to another preferred embodiment of the present invention, in the configuration of the fourth preferred embodiment, the linear valve of each wheel is constituted by a linear valve for increasing pressure and a linear valve for reducing pressure. (Preferred embodiment 5).

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electronic control unit 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 simplification.

In FIG. 1, reference numeral 10 denotes an electrically controlled hydraulic brake device. The brake device 10 is a master for pumping brake oil in response to a driver's depressing operation of a brake pedal 12. It has a cylinder 14. 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,
One ends of a brake hydraulic pressure supply conduit 18 for the front wheels and a brake hydraulic control conduit 20 for the rear wheels are connected to these master cylinder chambers, respectively. Brake oil pressure control conduit 1
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 8 and 20, respectively.

In the middle of the brake hydraulic pressure supply pipes 18 and 20, a normally open type solenoid on-off valve (master cut valve) 2
4F and 24R are provided, and the solenoid on-off valves 24F and 24R function as shut-off devices for controlling communication between the first master cylinder chamber 14A and the second 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 on-off valve 24RL via a normally-closed electromagnetic on-off valve 26.

A reservoir 30 is connected to the master cylinder 14, and one end of a hydraulic 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 for accumulating high-pressure oil 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 a 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 supply conduit 1 between the solenoid valve 24F and the wheel cylinder 22FL by a hydraulic control conduit 42.
8, a hydraulic control conduit 44 is connected to the wheel cylinder 22FR for the right front wheel, and a hydraulic control conduit 46 is connected to the brake hydraulic supply conduit 20 between the solenoid on-off valve 24R and the wheel cylinder 22RL. 4
8 is connected to a wheel cylinder 22RR for the right rear wheel.

In the middle of the hydraulic control conduits 42, 44, 46, and 48, normally-closed electromagnetic linear valves 50FL and 50
FR, 50RL, and 50RR are provided. Linear valve 50F
Wheel cylinder 2 for L, 50FR, 50RL, 50RR
Hydraulic control conduit 4 on the side of 2FL, 22FR, 22RL, 22RR
2, 44, 46 and 48 are hydraulic control conduits 52 and 5 respectively.
4, 56, 58 are connected to the hydraulic discharge conduit 40, and in the middle of the hydraulic control conduits 52, 54, 56, 58, respectively, are normally closed electromagnetic linear valves 60FL, 60FR, 60FR.
RL and 60RR are provided.

Linear valves 50FL, 50FR, 50RL, 50RR
Are wheel cylinders 22FL, 22FR, 22RL, respectively.
It functions as a pressure increase control valve for the 22RR, and the linear valve 60
FL, 60FR, 60RL, and 60RR function as pressure reducing control valves for the wheel cylinders 22FL, 22FR, 22RL, and 22RR, respectively, so that these linear valves cooperate with each other to supply high-pressure oil from the accumulator 38 to each wheel cylinder. The pressure increasing / decreasing control valve for controlling the discharge is constituted.

The hydraulic supply conduit 18 for the front wheels and the hydraulic control conduit 44 for the right front wheel are respectively connected to the corresponding wheel cylinders 22.
FL and 22FR are connected to each other by a connecting conduit 62F at a position close to them. A normally closed electromagnetic on-off valve 64F is provided in the middle of the connection 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 rear wheel hydraulic supply conduit 20 and the right rear wheel hydraulic control conduit 48 are connected to the connecting conduit 6 at a position close to the corresponding wheel cylinders 22RL and 22RR, respectively.
They are connected to each other by 2R. 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 communication between the wheel cylinders 22RL and 22RR.

As shown in FIG. 1, the pressure in the brake hydraulic control conduit 18 between the first master cylinder chamber 14A and the solenoid on-off valve 24F is defined as the first master cylinder pressure Pm1. First pressure sensor 66 to be detected
Is provided. Similarly, the second master cylinder chamber 14
B and hydraulic pressure control line 2 between solenoid valve 24R
0 is provided with a second pressure sensor 68 for detecting the pressure in the control conduit as a second master cylinder pressure Pm2. The first and second master cylinder pressures Pm1 and Pm2 are detected as values corresponding to the driver's braking operation force on the brake pedal 12.

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

In the brake hydraulic pressure supply conduits 18 and 20 between the solenoid valves 24F and 24R and the wheel cylinders 22FL and 22RL, respectively, the pressures in the corresponding conduits are detected as the pressures Pfl and Prl in the wheel cylinders 22FL and 22RL. Pressure sensors 74FL and 74RL are provided. A hydraulic control conduit 44 between the solenoid valves 50FR and 50RR and the wheel cylinders 22FR and 22RR, respectively.
And 48 are provided with pressure sensors 74FR and 74RR for detecting the pressure in the corresponding conduits as the pressures Pfr and Prr in the wheel cylinders 22FR and 22RR.

Electromagnetic on-off valves 24F and 24R, electromagnetic on-off valve 2
6. Motor 34, linear valve 50FL, 50FR, 50RL, 5
The 0RR, the linear valves 60FL, 60FR, 60RL, 60RR, and the solenoid on-off valves 64F and 64R are controlled by the electronic control unit 76 as described later in detail. The electronic control unit 76 includes a microcomputer 78 and a drive circuit 80.

Each solenoid on-off valve, each linear valve and electric motor 34
A drive circuit 80 from a battery not shown in FIG.
The drive current is supplied through the solenoid valve, and especially when the drive current is not supplied to each solenoid on-off valve, each linear valve, and the electric motor 34, the solenoid on-off valves 24F and 24R and the solenoid on-off valves 64F and 64R are maintained in the open state, Solenoid on-off valve 26, linear valve 50FL, 50FR, 50RL, 50RR, linear valve 60FL,
60FR, 60RL, and 60RR are maintained in the valve closed state (non-control mode).

Although the microcomputer 78 is not shown in detail in FIG. 1, for example, the central processing unit (CP)
U), a read-only memory (ROM), a random access memory (RAM), and an input / output port device, which are of a general configuration connected to each other by a bidirectional common bus. Good.

The microcomputer 78 supplies 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, A signal indicating the accumulator pressure Pa from the pressure sensor 72, and the pressure sensors 74FL to 74R.
Signals indicating pressures Pi (i = fl, fr, rl, rr) in the wheel cylinders 22FL to 22RR are input from R.

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

As will be described later, the microcomputer 78 stores the braking force control flow shown in FIG. 4, and is detected by the master cylinder pressures Pm1, Pm2 detected by the pressure sensors 66, 68 and the stroke sensor 70. The braking demand of the driver is estimated based on the depressed stroke St, the final target deceleration Gt of the vehicle is calculated based on the estimated braking demand, and the target wheel cylinder pressure of each wheel (based on the final target deceleration Gt). In the figure, target WC
Pti (i = fl, fr, rl, rr) is calculated, and based on the deviation between the target wheel cylinder pressure Pti and the actual wheel cylinder pressure Pi, the target drive current It for the linear valves 50FL to 50RR or 60FL to 60RR. Is calculated, and a drive current is supplied to each linear valve based on the target drive current It to control the wheel cylinder pressure of each wheel to the target wheel cylinder pressure Pti.

In this case, the microcomputer 78 operates the linear valve 50 when the braking control mode is the pressure increasing mode.
The valve opening amounts of FL, 50FR, 50RL, and 50RR are controlled in accordance with the target wheel cylinder pressure Pti. When the braking control mode is the pressure reducing mode, the linear valves 60FL, 60FR, and 60R are controlled.
The valve opening amounts of L and 60RR are controlled in accordance with the target wheel cylinder pressure Pti, and when the braking control mode is the holding mode, the linear valves 50FL to 50RR and 60FL to 60RR are maintained in the closed state.

The microcomputer 78 estimates the vehicle speed Vb based on the wheel speeds Vwi in a manner known in the art, as described later, and calculates a deviation between the estimated vehicle speed Vb and the wheel speed Vwi for each wheel. And calculates whether or not anti-skid control (referred to as ABS control in the figure) is required for each wheel based on the braking slip amount SLi and the like. If 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 drives the linear valve to the target drive current It. , The wheel cylinder pressure of each wheel becomes equal to the target wheel cylinder pressure Pti.
, Thereby performing anti-skid control to reduce the braking slip amount.

In particular, in the illustrated embodiment, the microcomputer 78 sets the target increasing / decreasing gradient ΔPti (i = fl, fr, rl, rr) of the wheel cylinder pressure as the deceleration Gxb or the braking slip amount SLi of the vehicle increases. Deceleration Gxb and braking slip amount SL of the vehicle so that the magnitude of
Target increase / decrease gradient ΔPt of wheel cylinder pressure based on i
i is calculated, the previous target wheel cylinder pressure is Ptfi, and the cycle time of the routine shown in FIG. 2 is ΔT. At the start of the anti-skid control, the following equation 1 is used. Until the condition for terminating the skid control is satisfied, the target wheel cylinder pressure Pti of the wheel is calculated in accordance with the following equation 2. Pti = Pi + ΔPtiΔT (1) Pti = Ptfi + ΔPtiΔT (2)

As will be described in detail later, the microcomputer 78 compensates for the deviation in the characteristic of the linear valve due to a change in the temperature of the linear valve based on the target drive current It and the actual drive current Im for the linear valve. Calculates the corrected target drive current Ita by correcting the target drive current It with the compensation coefficient Rr, and sets the default resistance value of the solenoid of the linear valve to Rs. Changes the power supply voltage not shown to Eb
And the switching frequency is set to Fs, and the duty-on time Don is calculated in accordance with the following equation 3 (see FIG. 4).
By outputting to the TMOSS, the corresponding linear valve is driven based on the corrected target drive current Ita. Don = {Ita / (Eb / Rs)} / Fs (3)

Further, the electronic control unit 76 operates 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 equal to or higher than a predetermined lower limit and equal to or lower than an upper limit. The electric motor 34 is driven to operate 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 intervals.

First, in 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 are read, and in step 20, For example, the target deceleration Gst is calculated based on the depression 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 target deceleration Gst and Gpt are calculated. , The final target deceleration Gt of the vehicle 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, at the start of the control, the electromagnetic on-off valve 26 is opened, and the electromagnetic on-off valves 24F and 24F are opened.
The valves R, 64F, and 64R are closed, and the drive of the oil pump 36 by the electric motor 34 is started.

Steps 30 to 160 are executed in chronological order for each wheel, for example, in the order of a front left wheel, a front right wheel, a rear left wheel, and a rear right wheel. In step 30, a procedure known in the art is used. It is determined whether or not anti-skid control is necessary. If a negative determination is made, the process proceeds to step 100, and if an affirmative determination is made, step 4 is performed.
Go to 0.

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

In step 50, based on the vehicle deceleration Gxb calculated based on the longitudinal acceleration Gx of the vehicle, a target pressure increase / decrease gradient ΔPti is obtained from a map group not shown in the drawing.
The calculation map is selected, and the target increasing / decreasing gradient ΔPti of the wheel cylinder pressure is calculated from the selected map 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 equal to the deceleration G of the vehicle.
The larger the value of xb or the braking slip amount SLi of the wheel is, the larger the positive value is calculated. And
When the braking control mode is the holding mode, it is set to 0.

In step 60, it is determined whether the anti-skid control is started or the braking control mode has changed from, for example, a pressure-reducing mode to a pressure-increasing mode. In step 70, the target wheel cylinder pressure Pti is calculated in accordance with the above equation 1, and when a negative determination is made, in step 80, the target wheel cylinder pressure Pti is calculated in accordance with the above equation 2, and in step 90, the target wheel cylinder pressure Pti is calculated. The target wheel cylinder pressure Pti calculated in step 110 or 120 is stored in a memory such as a RAM.

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

In step 130, the target drive current Ita after the correction is calculated by performing the characteristic deviation compensation processing for each linear valve according to the flowchart shown in FIG. 3, and in step 160, the correction is performed. The drive current is supplied to the corresponding linear valve based on the subsequent target drive current Ita, so that the wheel cylinder pressure Pi becomes the target wheel cylinder pressure Pti so that the linear valve 50FL
.About.50RR and 60FL.about.60RR are controlled, and thereafter, the flow returns to step 10.

Next, a description will be given of a linear valve characteristic deviation compensation control routine in the illustrated embodiment with reference to the flowchart shown in FIG. This characteristic deviation compensation control is executed for all of the linear valves 50FL to 50RR and 60FL to 60RR.

First, in step 132, the linear valve 5
It is determined whether or not the hydraulic circuit and the pressure sensors 74FL to 74RR shown in FIG. 1 constituted by 0FL to 50RR and the like are normal. For example, an electrical failure such as a disconnection or short circuit of the linear valve or the like is detected. A determination is made as to whether or not an abnormality has occurred, and whether or not an abnormality such as a leak or plug has occurred in the hydraulic circuit.
When the determination is affirmative, the routine proceeds to step 134.

In step 134, it is determined whether or not the drive current Im is normal.
It is determined whether or not m is within a predetermined design tolerance and an abnormality such as disconnection or resistance change has occurred in the ammeter 86,
When a negative determination is made, the process proceeds to step 152, and when an affirmative determination is made, the process proceeds to step 236.

In step 136, the corrected target drive current calculated in step 150 or 152, which will be described later three cycles before, is Ita (n-3), and the actual drive current Im in the current cycle is Im ( n), it is determined whether the target drive current Ita (n-3) is greater than 0 and the actual drive current Im (n) is greater than 0, that is, a situation where the drive current is supplied to the linear valve. Is determined, the process proceeds to step 152 when a negative determination is made, and proceeds to step 138 when an affirmative determination is made.

In step 138, the drive current ratio Ro is calculated as the ratio of the target drive current Ita (n-3) three cycles before to the actual drive current Im (n) in the current cycle according to the following equation (4). Note that the reason why the target drive current Ita (n-3) three cycles before is used in steps 136 and 138 is that the calculation delay is taken into account by filtering the actual drive current Im detected by the ammeter 86. Ro = Ita (n-3) / Im (n) (4)

In step 140, the temperature change of the solenoid of the linear valve to be subjected to the characteristic deviation compensation control is estimated based on the ambient temperature, the energizing time to the linear solenoid valve, and the like, and the drive current ratio Ro is estimated based on the estimated temperature change. The allowable range is determined, and it is determined whether or not the drive current ratio Ro calculated according to Equation 3 is within the allowable range. If a negative determination is made, the process proceeds to step 152, and an affirmative determination is made. If the answer is YES, in step 142, the number CT of positive determinations in step 140 is incremented by one.

In step 144, it is determined whether or not the number CT is equal to or greater than a predetermined number N (for example, a positive integer of about 100 to 200). If a negative determination is made, step 152 is performed. When the determination is affirmative, the sum Rsum of the latest N drive current ratios Ro is calculated in step 146, and the compensation coefficient Rr for the drive current is calculated in step 148 according to the following equation 5. , Are stored in a memory such as a RAM. Rr = Rsum / N (5)

In step 150, the drive current ratio Ro
Is reset to 0 and the number of times CT is 0
In step 152, the corrected target drive current Ita is calculated as the product of the target drive current It (n) of the current cycle and the compensation coefficient Rr according to the following equation 6,
Thereafter, the routine proceeds to step 160. Ita (n) = It (n) · Rr (6)

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

Then, in step 50, the deceleration Gxb of the vehicle, the braking control mode, and the braking slip amount SLi of the wheels
Based on the target pressure increase / decrease gradient ΔPti of the wheel cylinder pressure
When the anti-skid control is started or when the braking control mode is changed, an affirmative determination is made in step 60, whereby the target wheel cylinder pressure Pti is calculated in step 70 according to the above equation 1, If the braking control mode has not changed since the start of the anti-skid control, a negative determination is made in step 60, and in step 80, the target wheel cylinder pressure Pti is calculated according to the above equation (2).

Further, according to the illustrated embodiment, prior to the drive control of the linear valve, the characteristic deviation compensation control of the linear valve is performed as shown in FIG. 3, and a positive determination is made in steps 132 to 136. When the characteristic shift compensation control is possible by the operation, in steps 138 to 148, the target drive current Ita (n-3) three cycles before the actual drive current Im (n) of the latest N current cycles is calculated. A compensation coefficient Rr for the drive current is calculated as the average value of the ratio, and a target drive current Ita in which the target drive current It is corrected by the compensation coefficient Rr in step 152 is calculated, and correction is performed in step 160 in FIG. The corresponding linear valve is driven based on the subsequent target drive current Ita.

Therefore, even if a characteristic deviation occurs due to a temperature change of the solenoid in the linear valve, the target drive current Ita is corrected so as to absorb the characteristic deviation. Can accurately control the wheel cylinder pressure Pi to the target wheel cylinder pressure Pti, thereby accurately controlling the braking force of each wheel to a predetermined braking force required for reducing the amount of driver's braking operation and wheel slip. can do.

In particular, according to the illustrated embodiment, in step 138, the compensation coefficient Rr for the drive current is the ratio of the target drive current Ita (n-3) three cycles before to the actual drive current Im (n) in the current cycle. Ro is calculated, and steps 140-1
In step 48, the compensation coefficient Rr for the drive current is calculated as the average value of the ratio Ro for the latest N times, so that the compensation coefficient Rr is set to the ratio Ro calculated in step 138. It is possible to reduce the possibility that Rr is calculated to be an inappropriate value, thereby accurately correcting the target drive current according to the characteristic deviation of the linear valve.

Also, according to the illustrated embodiment, step 1
At 40, the temperature change of the solenoid of the linear valve to be subjected to the characteristic deviation compensation control is estimated based on the ambient temperature, the energizing time to the linear solenoid valve, and the like, and the allowable range of the drive current ratio Ro is determined based on the estimated temperature change. Along with
If the drive current ratio Ro calculated in step 138 is not within the allowable range, the drive current ratio Ro is not used in the calculation of the compensation coefficient Rr in steps 146 and 148, so the determination in step 140 is made. Comparing with the case where it is not possible, it is possible to calculate the compensation coefficient Rr that accurately corresponds to the characteristic deviation of the linear valve.

Further, according to the illustrated embodiment, the target drive current Ita (n-3) three cycles before is calculated in steps 136 and 138 in consideration of the calculation delay by filtering the detected actual drive current Im. In this step, compared to the case where the calculation delay is not considered by the filtering of the actual drive current Im in these steps, it is determined whether or not the drive current is supplied to the linear valve. The calculation of the current ratio Ro can be performed accurately.

According to the illustrated 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 calculated based on the previous target wheel cylinder pressure Pti. Since the calculation is performed based on the cylinder pressure Ptfi, the target wheel cylinder pressure Pti at the start of the anti-skid control can always be set to a value lower than the actual wheel cylinder pressure Pi and to an appropriate value according to the wheel slip state. Thereby, 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 according to the slip state of the wheel, thereby realizing Wheel cylinder pressure Pi properly and precisely according to the wheel slip condition. Controlled, the anti-skid control can be performed properly and effectively to.

According to the illustrated 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 control mode changes, the target wheel cylinder pressure Pti
Is calculated based on the previous target wheel cylinder pressure Ptfi.
ti can be appropriately set according to the wheel slip state, whereby the wheel cylinder pressure can be properly controlled without delay according to the wheel slip state.

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

For example, in the above-described embodiment, in step 140, the temperature change of the solenoid of the linear valve to be subjected to the characteristic deviation compensation control is estimated based on the ambient temperature, the energizing time to the linear solenoid valve, and the like. Although the allowable range of the drive current ratio Ro is determined based on the temperature change, the allowable range of this determination may be set to a fixed range.

In the above-described embodiment, in step 148, the compensation coefficient Rr for the drive current is calculated as the average of the latest N times of the ratio Ro. The calculation may be performed by performing a smoothing process such as a moving average process on the average value of the ratio Ro for the latest N times.

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. The cylinder pressure Pti may be calculated in any manner known in the art.

[0075]

As is apparent from the above description, according to the first aspect of the present invention, the linear valve can be accurately controlled irrespective of the characteristic deviation of the linear valve, and the target drive current and the actual drive current can be controlled. When the deviation from the drive current is out of the predetermined allowable range, the degree of contribution of the deviation to the compensation of the characteristic deviation is reduced, so that the characteristic deviation of the linear valve is inappropriately determined based on the inappropriate deviation due to noise or the like. Compensation is reliably prevented, whereby the target drive current can be accurately corrected according to the characteristic deviation of the linear valve.

According to the second aspect of the present invention, the predetermined allowable range is variably set in accordance with the estimated temperature change of the linear valve. According to the configuration of claim 3, the target drive current is corrected based on the average value of the plurality of deviations, whereby the characteristic deviation of the linear valve is corrected. Since the compensation is performed, the characteristic deviation of the linear valve can be compensated more appropriately than when the target drive current is corrected based on one deviation between the target drive current and the actual drive current.

According to the fourth aspect of the present invention, when the deviation between the target driving current and the actual driving current is out of the predetermined allowable range, the contribution of the deviation to the compensation of the characteristic deviation is reduced to zero. Therefore, it is possible to reliably prevent the characteristic deviation of the linear valve from being improperly compensated based on the deviation outside the predetermined allowable range.

[Brief description of the 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.

FIG. 2 is a flowchart illustrating a braking control routine in the illustrated embodiment.

3 is a flowchart showing a linear valve characteristic deviation compensation control routine in step 130 of FIG. 2;

FIG. 4 is an explanatory diagram showing a relationship between a switching cycle Fs of a signal output to a drive circuit and a duty-on time Don.

[Explanation of symbols]

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

Claims (4)

[Claims] A linear valve for increasing / decreasing a wheel cylinder pressure by controlling the supply / discharge of a working liquid to / from a wheel cylinder provided for each wheel, and a driving current for the linear valve according to a state of a vehicle. In a vehicle braking control device having control means for controlling a wheel cylinder pressure by controlling, a characteristic deviation of the linear valve is compensated based on a deviation between a target drive current and an actual drive current for the linear valve. And a compensating means, wherein the compensating means includes a contribution degree reducing means for reducing a contribution degree of the deviation to the compensation by the compensating means when the deviation is outside a predetermined allowable range. apparatus. 2. The vehicle brake control device according to claim 1, wherein said compensation means variably sets said predetermined allowable range in accordance with an estimated temperature change of said linear valve. 3. The linear valve according to claim 2, wherein the compensating means calculates the deviation at predetermined time intervals and compensates for a characteristic deviation of the linear valve by correcting a target drive current based on an average value of the plurality of deviations. The brake control device for a vehicle according to claim 1 or 2, wherein 4. The apparatus according to claim 1, wherein said contribution degree reducing means reduces the contribution degree of said deviation to compensation by said compensating means to zero when said deviation is outside a predetermined allowable range. Vehicle brake control device.