JP2000062597A - Linear solenoid drive control method and device - Google Patents

Abstract

(57) Abstract: In a method and an apparatus for driving a linear solenoid for duty control, even when the resistance value of the linear solenoid changes, the linear solenoid is energized with an appropriate duty at the next duty control. SOLUTION: A current is supplied to a linear solenoid LS to drive a control means CM, and a control target TC (for example, a brake fluid pressure control device) is controlled by the control means CM (for example, a linear solenoid valve). The duty setting means DS sets a target current for the linear solenoid LS according to the control state of the control means CM, and sets a duty corresponding to the target current. Then, the adjusting means AD drives the linear solenoid LS in accordance with the duty set by the duty setting means DS, and the energizing current detected by the current detecting means CD and the duty setting means DS
Corrects the relationship between the duty and the target current according to the comparison result with the set target current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear solenoid drive control method and device, and more particularly to a linear solenoid drive control method and device suitable for a pressure increasing solenoid valve and a pressure reducing solenoid valve of a vehicle brake fluid pressure control device. .

[0002]

2. Description of the Related Art Various methods and devices are known as control methods and devices for energizing a linear solenoid to drive control means, and controlling the controlled object by this control means. For example, regarding a brake fluid pressure control device for a vehicle, a device called a brake-by-wire has attracted attention, and use of a linear solenoid has been proposed for this. This brake-by-wire calculates the target wheel cylinder hydraulic pressure (or target vehicle body acceleration) based on the pedal effort or stroke amount of the brake pedal, and supplies current to the pressure increasing solenoid valve to increase or decrease the wheel cylinder hydraulic pressure. The current is supplied to the solenoid valve to reduce the wheel cylinder hydraulic pressure, and the actual wheel cylinder hydraulic pressure (or actual vehicle body acceleration) is controlled to match the target wheel cylinder hydraulic pressure (or target vehicle body acceleration). is there.

[0003]

When a linear solenoid is used for controlling the pressure-increasing solenoid valve and the pressure-decreasing solenoid valve of the brake fluid pressure control device, or for controlling the engine of a vehicle, etc., duty control of the energizing current is generally used. Is performed. That is, the ratio of the energizing time to the time of one cycle is called the duty ratio, and its abbreviation is called the duty. The duty control of the energizing current is performed digitally by controlling the ratio of energizing and de-energizing. Since the current is variably controlled, the processing is easy.

However, the resistance value changes due to the heat generation of the coil that constitutes the linear solenoid and the change in the ambient temperature, and even if a predetermined duty is given, the energizing current is not uniquely determined. Therefore, for example, in the brake fluid pressure control device, the wheel cylinder fluid pressure regulated by the linear solenoid valve may cause a delay in response or hunting even if feedback control is performed.

Therefore, in the present invention, in a duty-controlled linear solenoid drive control method and apparatus, even when the resistance value of the linear solenoid changes, it is an object to energize the linear solenoid at an appropriate duty during the next duty control. And

[0006]

In order to solve the above-mentioned problems, the linear solenoid drive control method of the present invention, as set forth in claim 1, energizes the linear solenoid to drive the control means to perform the control. In a linear solenoid drive control method for controlling a controlled object by means, a target current for the linear solenoid is set according to a control status of the control means, a duty corresponding to the target current is set, and the target current is set according to the duty. Driving the linear solenoid, detecting the energizing current to the linear solenoid, comparing the energizing current with the target current, and correcting the relationship between the duty and the target current according to the comparison result. Is. The relationship between the duty and the target current may be a map having both the vertical axis and the horizontal axis, or an arithmetic expression expressing the relationship between the two.

Further, as described in claim 2, it is preferable that a predetermined current within the drive start limit is supplied to the linear solenoid even when the control means is not driven.

When correcting the relationship between the duty and the target current, at least one of the upper limit and the lower limit of at least one of the duty and the target current is set as described in claim 3. It may be provided. Further, when correcting the relationship between the duty and the target current, the correction amount is divided into a plurality of times in order to prevent inappropriate correction due to momentary fluctuations of noise and the like, and the correction amount per time is corrected. May be limited within a predetermined range. Further, when a plurality of control means controlled under substantially the same energization condition are provided, the relationship between the duty and the target current is set in order to prevent improper correction due to a failure of each control means. At the time of correction, the relationship between the duty of the linear solenoid and the target current for each control means may be corrected so as to maintain a predetermined relationship.

On the other hand, according to the linear solenoid drive control device of the present invention, as described in claim 4, the linear solenoid drive control for energizing the linear solenoid to drive the control means and control the controlled object by the control means. In the device, a duty setting means for setting a target current for the linear solenoid in accordance with the control status of the control means, and a duty corresponding to the target current, and a current detection means for detecting a conduction current for the linear solenoid. Driving the linear solenoid in accordance with the duty set by the duty setting means, comparing the energizing current detected by the current detecting means with the target current set by the duty setting means, and depending on the comparison result, It is assumed to have an adjusting means for correcting the relationship between the duty and the target current. Door can be.

According to a fifth aspect of the present invention, the adjusting means determines the relationship between the duty and the target current when the energizing current of the linear solenoid is determined to be smaller than the target current. It is preferable that the energization current is corrected so as to increase, and then the relationship between the duty and the target current is gradually corrected so that the energization current decreases when the linear solenoid is not energized.

Further, when the adjusting means determines that the energized current is larger than the target current when the linear solenoid is energized, as described in claim 6,
The relationship between the duty and the target current may be corrected so that the energization current decreases, and then the relationship between the duty and the target current may be retained even when the linear solenoid is not energized.

Further, as described in claim 7, it is preferable that the adjusting means supplies a predetermined current within a drive start limit to the linear solenoid even when the control means is not driven.

When the adjusting means corrects the relation between the duty and the target current, at least one of the upper limit and the lower limit of at least one of the duty and the target current is set. It may be configured to give either one of the restrictions.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a linear solenoid drive control device of the present invention. The linear solenoid LS is energized to drive the control means CM, and the control means CM controls the controlled object TC. There is. The control means CM is, for example, a linear solenoid valve, and the controlled object TC is a brake fluid pressure control device. Further, the duty setting means DS sets a target current for the linear solenoid LS according to the control status of the control means CM, and sets a duty corresponding to this target current. Then, the adjusting means AD drives the linear solenoid LS in accordance with the duty set by the duty setting means DS, and the energizing current detected by the current detecting means CD and the duty setting means DS.
The target currents set by are compared, and the relationship between the duty and the target current is corrected according to the comparison result.

When it is determined that the energizing current is smaller than the target current when the linear solenoid LS is energized, the adjusting means AD of the present embodiment corrects the relationship between the duty and the target current so that the energizing current increases. After that, when the linear solenoid LS is not energized, the relationship between the duty and the target current may be gradually corrected in the direction in which the energized current decreases. Further, when it is determined that the energizing current is larger than the target current when the linear solenoid LS is energized, the adjusting means AD corrects the relationship between the duty and the target current so that the energizing current decreases, and then the linear solenoid LS. It is configured such that the relationship between the duty and the target current is maintained even when the current is not energized. Furthermore, adjustment means AD
Is configured to supply a predetermined current within the drive start limit to the linear solenoid LS even when the control means CM is not driven. Further, when the adjusting means AD corrects the relationship between the duty and the target current, it is configured to give at least one of the upper limit and the lower limit to at least one of the duty and the target current. Note that various other restrictions are set, which will be described later.

FIG. 2 shows an embodiment of a normally closed type linear solenoid valve in which the control means CM of the present invention is applied to a brake fluid pressure control device and used as the fluid pressure control valve, which has a hollow portion. A coil 2 is wound around a housing 1, and a suction hole 3 and a discharge hole 4 communicating with the hollow portion are formed.
A plunger 5 is slidably accommodated in the hollow portion of the housing 1, and a valve body 6 of the plunger 5 is arranged to be seated in the suction hole 3 by a spring 8. For example, in this embodiment, the brake fluid is supplied to the suction hole 3 and discharged from the discharge hole 4, and the brake fluid is used as the control medium.

When the coil 2 is not energized, the suction hole 3
Is closed by the valve body 6 of the plunger 5, and when the coil 2 is energized, the plunger 5 is driven and the suction hole 3 opens. When the sum of the pressure difference between the suction hole 3 side and the discharge hole 4 side acting on the plunger 5 and the suction force due to the coil energization becomes equal to or less than the biasing force of the spring 8, the suction hole 3 is moved by the valve body portion 6 of the plunger 5. Is blocked. In this way, the brake fluid pressure is controlled in proportion to the duty-controlled current. It should be noted that the coil 2 is connected to an electronic control unit ECU, which will be described later, and a sensor A which is a current detecting means.

FIG. 3 shows the overall construction of an embodiment in which the linear solenoid of the present invention is applied to a brake fluid pressure control device.
Wheel cylinders W of the wheels FL, FR, RL, RR from the power hydraulic pressure source PS according to the operation of the brake pedal BP.
The power hydraulic pressure is supplied to fl, Wfr, Wrl, and Wrr. These wheel cylinders Wfl etc. are connected to the power hydraulic pressure source PS via the pressure increasing solenoid valve SIfl etc.
It is connected to the. Further, the wheel cylinder Wfl and the like are connected to a reservoir RS of a master cylinder MC described later via a pressure reducing solenoid valve SDfl and the like. The wheel FL indicates the wheel on the front left side as viewed from the driver's seat, hereinafter the wheel FR indicates the front right side, the wheel RL indicates the rear left side, and the wheel RR indicates the rear right side wheel.

The power hydraulic pressure source PS is provided with a hydraulic pressure pump HP and an accumulator AC, and the hydraulic pressure pump HP is driven by an electric motor (not shown) to introduce the brake fluid from the suction side to raise the pressure to a predetermined pressure. It is configured to output from the discharge side, and the accumulator AC is configured to accumulate the discharge brake hydraulic pressure of the hydraulic pump HP.

In this embodiment, all the pressure-increasing solenoid valves SIfl, SIfr, SIrl, SIrr and the pressure reducing solenoid valves SDfl, SDfr on the front wheel side are normally closed linear solenoid valves, and the pressure reducing solenoid valve SDrl on the rear wheel side. , SDrr are normally-open linear solenoid valves, and the normally-closed linear solenoid valve is constructed as shown in FIG.

Further, the wheel cylinders Wfr, Wfl of the front wheels FR, FL are provided with solenoid valves SE1, SE.
It is connected via 2 to the master cylinder MC. These solenoid valves SE1 and SE2 are normally in the positions shown in FIG. 3, and function as so-called cut-off valves when the power hydraulic pressure source PS is normal. Thus, the master cylinder MC
Is a solenoid valve S when the power hydraulic pressure source PS fails.
E1 and the like are set to the open position, the brake fluid in the reservoir RS is boosted in response to the operation of the brake pedal BP, and the wheel F is rotated.
The master cylinder hydraulic pressure is output to the L and FR brake hydraulic pressure systems.

The master cylinder MC of the present embodiment is a tandem type master cylinder having two pressure chambers C1 and C2. The pressure chamber C1 is connected to the wheel cylinder Wfr of the wheel FR, and the pressure chamber C2 is the wheel of the wheel FL. It is communicatively connected to the cylinder Wfl. That is, as shown in FIG.
Pistons PN1, PN2 and PN3 are slidably accommodated in a cylinder CR, pressure chambers C1 and C2 and a liquid chamber C3 are defined, and compression springs S1 and S are respectively provided in the chambers.
2, S3 are housed. Each room C1, C2, C3
Although not connected to the reservoir RS when the brake pedal BP is not operated, when the pistons PN1, PN2 and PN3 move forward in response to the operation of the brake pedal BP, the reservoir R
The communication with S is cut off.

Piston PN in the master cylinder MC
3, the spring S3 and the liquid chamber C3 constitute a pedal stroke simulator SM, and as will be described later, the master cylinder MC does not operate when the power hydraulic pressure source PS is normal, and therefore corresponds to the operating force applied to the brake pedal BP. This is to secure a stroke of a size that The liquid chamber C3 is connected to the reservoir RS through a normally closed solenoid valve SC.

The pressure increasing solenoid valve SIfl and the pressure reducing solenoid valve SDfl and the motor (not shown) of the hydraulic pump HP are connected to an electronic control unit ECU.
Drive control is performed by this electronic control unit ECU. Figure 3
The member indicated by P is a pressure sensor, and these are also connected to the electronic control unit ECU. Although not shown, an operation force sensor that detects an operation force applied to the brake pedal BP and a stroke sensor that detects a stroke of the brake pedal BP are provided, and the electronic control unit EC is provided.
It is connected to U. Then, in the electronic control unit ECU, the target hydraulic pressure of the wheel cylinder hydraulic pressure of each wheel cylinder Wfl etc. is calculated, and the pressure increasing solenoid valve SIfl etc. and the pressure reducing solenoid valve SDfl etc. are made to match the target hydraulic pressure. It is controlled to open and close.

Further, a wheel speed sensor (not shown) is arranged on each wheel, and these are connected to an electronic control unit ECU, and the rotation speed of each wheel, that is, the number of pulses proportional to the wheel speed. The signal is input to the electronic control unit ECU. Thus, when the power hydraulic pressure source PS is normal, for example, when the wheels tend to lock during braking, the electronic control unit ECU controls the opening and closing of the pressure increasing solenoid valve SIfl and the pressure reducing solenoid valve SDfl to prevent opening. Skid control is performed.

Although not shown, the electronic control unit ECU includes a microcomputer including a processing unit (CPU), a memory (ROM, RAM), an input port and an output port, which are connected to each other via a bus. The memory (ROM) stores programs for various processes including the flowcharts shown in FIGS. 4 and 5, and the processing unit (CPU) executes the programs while an ignition switch (not shown) is closed. The memory (RAM) temporarily stores variable data necessary for executing the program.

In the electronic control unit ECU, the control means CM for controlling the pressure-increasing solenoid valve SIfl and the like shown in FIG. 1 is constructed, and the current detecting means for detecting the energizing current to the pressure-increasing solenoid valve SIfl and the like. The CD is made up.
Further, a duty setting means DS for setting the duty corresponding to the target current, an adjusting means AD for adjusting the duty of the energizing current to the pressure increasing solenoid valve SIfl and the like are configured.

The operation of the embodiment having the above-mentioned structure will be described. When the power hydraulic pressure source PS is normal and the brake pedal BP is operated, the solenoid valve S is operated.
E1 and SE2 are excited to the closed position, and the pressure reducing solenoid valves SDrl and SDrr are excited to the closed position. After that, the energizing current to the pressure increasing solenoid valve SIfl and the like is duty-controlled so that the braking force according to the operation of the brake pedal BP is applied from the power hydraulic pressure source PS. In this case, after the communication between each chamber of the master cylinder MC and the reservoir RS is cut off, the piston PN1
And PN2 cannot be advanced, but since the solenoid valve SC is excited to be in the open position, the liquid chamber C3 communicates with the reservoir RS and the piston PN3 moves forward against the biasing force of the spring S3. Becomes Thus, the brake pedal BP is ensured to have a stroke corresponding to the applied operating force.

For example, when the anti-skid control is performed during the brake operation and it is determined that the wheels FR tend to lock, for example, the solenoid valve SE1 remains in the closed position and the pressure increasing solenoid valve SIfr is set in the closed position. At the same time, the pressure reducing solenoid valve SDfr is opened. Thus, the wheel cylinder Wfr is a pressure reducing solenoid valve S
By communicating with the reservoir RS via Dfr, the brake fluid in the wheel cylinder Wfr flows out into the reservoir RS and is depressurized. Thus, independent braking force control is performed for each wheel.

When the power hydraulic pressure source PS fails, the solenoid valves SC, SE1, SE2, the pressure increasing solenoid valve SIfl and the pressure reducing solenoid valve SDfl are de-excited and returned to the state of FIG. When the brake pedal BP is operated in this state, the liquid chamber C3 of the master cylinder MC
After the communication between the reservoir and the reservoir RS is cut off, the piston PN
3 cannot be advanced, but solenoid valve SE1,
Since SE2 is in the open position, the pistons PN1 and PN2 are
Moves forward in response to the operation of the brake pedal BP, and master cylinder hydraulic pressure is supplied to the wheel cylinders Wfr and Wfl from the pressure chambers C1 and C2 of the master cylinder MC via the solenoid valves SE1 and SE2, respectively.

When the brake pedal BP is not operated,
The solenoid valves SC, SE1, SE2, the pressure-increasing solenoid valve SIfl, etc., and the pressure-reducing solenoid valve SDfl, etc. are de-energized and brought into the state of FIG.
Since N1 to PN3 are returned to the initial positions, each chamber of the master cylinder MC communicates with the reservoir RS. Therefore, neither the power hydraulic pressure source PS nor the master cylinder MC supplies brake hydraulic pressure to the wheel cylinders Wfl and the like.

In the present embodiment configured as described above, the electronic control unit ECU performs a series of processes such as braking force control, and an ignition switch (not shown).
When is closed, execution of the program corresponding to the flowcharts of FIGS. FIG. 4 shows control of linear solenoid valves such as the pressure increasing solenoid valve SIfl and the pressure reducing solenoid valve SDfl. First, in step 101, the electronic control unit ECU is initialized. Next, at step 102, the process waits until a predetermined time (for example, 7 ms) elapses. That is, in the present embodiment, the following processing is performed in a cycle of 7 ms, but it is not particularly limited to this time.

In step 103, the stroke and pedaling force of the brake pedal BP, the state of the brake switch (not shown), the energizing current, the vehicle body acceleration, the wheel cylinder hydraulic pressure (Pwc), the accumulator hydraulic pressure (Pac), etc. are controlled. Various processes necessary for the above are performed. Further, in step 104, the duty-target current map of each solenoid valve is corrected based on the calculated control target current and the actual energized current. This will be described later with reference to FIGS. 5, 8 and 9.

Next, the process proceeds to step 105 and step 1
The target wheel cylinder hydraulic pressure is calculated based on the stroke of the brake pedal BP, the pedal effort, and the like that have been input at 03. The target wheel cylinder hydraulic pressure is corrected by performing feedback control based on the relationship between the target wheel cylinder hydraulic pressure and the actual wheel cylinder hydraulic pressure. Thereafter, the corrected target wheel cylinder hydraulic pressure is referred to as the target wheel cylinder hydraulic pressure. Call.

Then, in step 106, the target wheel cylinder hydraulic pressure obtained in step 105 and the actual wheel cylinder hydraulic pressure are compared in magnitude, and either the pressure increase, the holding pressure or the pressure reduction is performed according to the comparison result. Pressure mode is set. When the actual wheel cylinder hydraulic pressure is lower than the target wheel cylinder hydraulic pressure, the target current and duty of the pressure increasing solenoid valve SIfl and the like are set to the value of the pressure increasing mode in step 107, and step 10
At 8, the target current and duty of the pressure reducing solenoid valve SDfl etc. are also set to the values of the pressure increasing mode. In particular,
A target current is set based on a target wheel cylinder hydraulic pressure-target current map (not shown) representing solenoid valve characteristics, and a duty corresponding to the target current is set based on a target current-duty map (for example, FIG. 8). To be done. The same processing is performed in the holding mode of steps 109 and 110 and the depressurization mode of steps 111 and 112.

The above process is repeated until it is completed for all the wheels, and when it is judged to be completed in step 113, the routine proceeds to step 114, where the target current and duty are output. Thus, the wheel cylinder hydraulic pressure is controlled according to the brake operation input by the vehicle driver. Although the wheel cylinder hydraulic pressure is used as the control target in the present embodiment, the same process can be performed by using the longitudinal acceleration of the vehicle.

FIG. 5 shows an example of the correction process performed in step 104 of FIG. First, in step 201, it is determined whether or not the target solenoid valve is energized. If it is energized, the process proceeds to step 202, and the current that is actually energized (hereinafter referred to as the actual current) is compared with the target current. When it is determined in step 202 that the actual current is larger than the target current by a predetermined ratio (α) or more, the process proceeds to step 203, and the correction coefficient k * is set to a value (k * −β) smaller by a predetermined amount (β). , The correction coefficient k * is compared with a predetermined lower limit value KL in step 204. If the correction coefficient k * is smaller than the lower limit value KL, step 205
The correction coefficient k * is set to the lower limit value KL. In addition, * represents each wheel of the vehicle.

On the other hand, if it is not determined in step 202 that the actual current is larger than the target current by the predetermined ratio (α) or more, the process proceeds to step 206, and the actual current is further than the target current by the predetermined ratio (α) or more. It is determined whether or not it is small, and if it is determined to be small, the routine proceeds to step 207, where the correction coefficient k *
Is set to a value (k * + β) larger by a predetermined amount (β),
The correction coefficient k * after the setting is compared with a predetermined upper limit value KU in step 208. If the correction coefficient k * is larger than the upper limit value KU, the routine proceeds to step 209, where the correction coefficient k * is set to the upper limit value KU. When it is determined to be no in steps 204, 206 and 208, the process proceeds to step 217.

If it is determined in step 201 that the solenoid valve in question is not energized, the routine proceeds to step 210, where it is determined whether the correction coefficient k * is positive or negative. If the correction coefficient k * is not positive, the process proceeds to step 217 as it is, but if it is positive, the process proceeds to step 211, and the non-energization time (T *) is counted up (T * + 1). Then, in step 212, the non-energization time (T *) is the limit value T.
If it is less than the limit value Tmax, the process proceeds to the next step 214 as it is, but if it exceeds the limit value Tmax, the non-energization time (T *) is set to the limit value Tmax in step 213. Then, the process proceeds to step 214. Then, in step 214, the correction coefficient k * is set to a value (k * −γ) reduced by the correction amount (γ) set according to the map of FIG. 7, and in step 215, the correction coefficient k * is negative. It is determined whether or not the value has been reached. Therefore,
If the correction coefficient k * is positive or 0, the process proceeds to step 21.
7. If the correction coefficient k * has a negative value, the correction coefficient k * is set to 0 in step 216, and then the process proceeds to step 217.

In step 217, the steps 201 to 21 are performed for all the linear solenoid valves.
It is determined whether or not the process of No. 6 has been performed, and if so, the process proceeds to step 218, and if not, step 201.
Return to. In step 218, the target current-duty map map (d) at that time is corrected using the correction coefficient k * set as described above to obtain corrected map (c) [map (c) = Map (d) · (1 + k *)].

FIG. 8 shows an example of the target current-duty map used in the embodiment of the present invention. The duties Dt1 to Dt3 are larger as the subscript is larger as shown in FIG. Further, FIG. 9 shows the relationship between the duty and the actual current. The actual currents Ia1 to Ia3 and the duties Dt1 to Dt3 also show larger values as the subscripts increase.
For example, when the duty Dt2 corresponding to the target current It2 is set according to the characteristic indicated by the solid line in FIG. 8, and if the resistance becomes larger than that when the coil of the linear solenoid valve is not energized, the dashed line in FIG. As shown, the actual current is Ia1, which is lower than the original actual current Ia2 corresponding to the target current It2. At this time, in order to obtain the actual current Ia2, it is necessary to set the duty Dt3 corresponding to the actual current Ia2 in FIG.

Therefore, in this case, the characteristic shown by the solid line in FIG. 8 is corrected to the characteristic shown by the broken line, and the duty at the time of energizing the linear solenoid in the next cycle is set according to the characteristic shown by the broken line. Then, at the next duty control, the duty Dt3 corresponding to the target current It2 is set according to the characteristic shown by the broken line in FIG. 8, and eventually adjusted to the actual current Ia2 corresponding to the target current It2. The characteristic indicated by the alternate long and short dash line in FIG. 8 and the relationship indicated by the alternate long and short dash line in FIG.
For example, it is used when the resistance of the coil of the linear solenoid valve becomes smaller than the normal time due to a decrease in environmental temperature.

Thus, in this embodiment, the relationship between the duty and the target current is corrected according to the energizing current to the linear solenoid, so when the linear solenoid is energized in the next cycle, that is, At the next duty control, the difference between the target current and the actual energizing current is small, and good current responsiveness can be secured.
Further, when setting the correction coefficient k *, the upper limit (KU) and the lower limit (KL) are given, and the correction can be performed within an appropriate limit. Therefore, it is possible to avoid an inappropriate correction due to a failure or the like. Moreover, since the correction amount per time is limited within the predetermined range (β), it is possible to prevent improper correction due to momentary fluctuation of noise or the like.

FIG. 6 shows another example of the correction process performed in step 104 of FIG. In this example, even when the linear solenoid valve is not controlled, a current to such an extent that the linear solenoid valve does not operate is supplied to correct the duty-target current map. First, in step 301, it is determined whether or not the actual current is larger than the target current by a predetermined ratio (α) or more. (K * -β), and the correction coefficient k * is compared with a predetermined lower limit value KL in step 303. If the correction coefficient k * is smaller than the lower limit value KL, the routine proceeds to step 304, where the correction coefficient k * is set to the lower limit value KL.

On the other hand, if it is not determined in step 301 that the actual current is larger than the target current by the predetermined ratio (α) or more, the process proceeds to step 305, and the actual current is more than the target current by the predetermined ratio (α) or more. It is determined whether or not it is small, and if it is determined to be small, the routine proceeds to step 306, where the correction coefficient k *
Is set to a value (k * + β) larger by a predetermined amount (β),
The correction coefficient k * after the setting is compared with a predetermined upper limit value KU in step 307. If the correction coefficient k * is larger than the upper limit value KU, the routine proceeds to step 308, where the correction coefficient k * is set to the upper limit value KU. Note that steps 303, 305 and 307
When it is determined to be no, the process proceeds to step 309. Then, in step 309, it is determined whether or not the processes of steps 301 to 308 have been performed for all the linear solenoid valves, and if so, the process proceeds to step 310, and if not, the process returns to step 301.

In step 310, the correction coefficient k1n of the pressure increasing solenoid valve SIfr of the front wheel FR is compared with the correction coefficient k2n of the pressure increasing solenoid valve SIfl of the wheel FL. When it is determined that the two greatly deviate from each other by exceeding the predetermined difference A, these correction coefficients k1n,
It is determined that k2n is inappropriate, and the processing proceeds to step 311, and the correction coefficients k1n and k2n are replaced with the previous values k1 (n-1) and k2 (n-1), respectively. Similarly, in steps 312 and 313, the correction coefficient k3n of the pressure-increasing solenoid valve SIrr of the rear wheel RR and the correction coefficient k4n of the pressure-increasing solenoid valve SIrl of the wheel RL are compared with each other, and the two are significantly different. If it is determined that the previous values k3 (n-1) and k4 (n-
Replaced by 1).

Further, in steps 314 and 315, the correction coefficient k5n of the pressure reducing solenoid valve SDfr of the wheel FR on the front wheel side and the correction coefficient k6n of the pressure reducing solenoid valve SDfl of the wheel FL are compared with each other, and they are greatly separated. When judged, the previous values k5 (n-1) and k6 (n-1) respectively
Is replaced by Further, in steps 316 and 317, the pressure reducing solenoid valve SDrr of the rear wheel RR is set.
Correction coefficient k7n and the pressure reducing solenoid valve SD of the wheel RL
When the correction coefficient k8n of rl is compared with each other and it is determined that they are significantly different from each other, the previous values k7 (n-1) and k7 respectively
Replaced by 8 (n-1). As described above, the correction coefficient k
1n to k8n are modified, and these are used to correct the control map in the same manner as step 218 in FIG. 5 (omitted in FIG. 6).

As described above, in the present embodiment, the upper limit (KU) and the lower limit (KL) are set when the correction coefficient k * is set.
Since the limitation is given and correction can be performed within an appropriate limit, it is possible to avoid improper correction due to failure etc., and the correction amount per time is within the predetermined range (β). Since it is limited, it is possible to prevent inappropriate correction due to instantaneous fluctuations such as noise. Further, although the plurality of solenoid valves are controlled under substantially the same energization condition, each solenoid valve is maintained in a predetermined relationship, so that it is possible to prevent improper correction due to each failure or the like.

[0049]

Since the present invention is configured as described above, it has the following effects. That is, in the linear solenoid drive control method and the linear solenoid drive control device of the present invention, the target current for the linear solenoid is set according to the control status of the control means, the duty corresponding to the target current is set, and the duty is set to the duty. The linear solenoid is driven in response to this, and the relationship between the duty and the target current is corrected according to the comparison result of the current supplied to the linear solenoid and the target current.Therefore, when the resistance value of the linear solenoid changes, Even in the next duty control, the linear solenoid can be energized with an appropriate duty.

Further, as described in claims 2 and 7, even when the control means is not driven, if the predetermined current within the drive start limit is supplied to the linear solenoid, the correction is appropriately performed. Since the processing can be performed and the correction processing can always be performed, it is possible to secure a better current responsiveness.

Further, as described in claims 3 and 8, when correcting the relationship between the duty and the target current, at least one of the upper limit and the lower limit of at least one of the duty and the target current is limited. If you give, because it can be corrected within the appropriate limit,
Inappropriate correction due to a failure or the like can be avoided.

In the linear solenoid drive control device of the present invention, when the energizing current to the linear solenoid tends to decrease at a predetermined duty, the resistance value increases due to the temperature rise due to energizing the linear solenoid. Therefore, if the adjusting means is configured as described in claim 5, the relationship between the duty and the target current is corrected in the direction in which the energization current increases, so that when the linear solenoid is energized next time. Can set the duty based on a more appropriate relationship between the duty and the target current.

Alternatively, when the energizing current to the linear solenoid tends to increase at a predetermined duty, it is considered that the resistance value of the linear solenoid is decreasing due to the change in the ambient temperature, and the resistance value is de-energized. Therefore, if the adjusting means is configured as described in claim 6, the relationship between the duty and the target current can be maintained, and therefore, when the linear solenoid is energized next time, it is more appropriate. The duty can be set based on the relationship between the duty and the target current.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a linear solenoid drive control device of the present invention.

FIG. 2 is a sectional view of a linear solenoid valve according to an embodiment of the present invention.

FIG. 3 is an overall configuration diagram of an embodiment of a vehicle brake fluid pressure control device including a linear solenoid drive control device of the present invention.

FIG. 4 is a flowchart showing the overall target current setting according to the embodiment of the present invention.

FIG. 5 is a flowchart showing an example of a correction process according to the embodiment of the present invention.

FIG. 6 is a flowchart showing another example of the correction processing according to the embodiment of the present invention.

FIG. 7 is a graph showing a correction coefficient k * used for a correction process according to the embodiment of the present invention.

FIG. 8 is a graph showing a target current-duty map used in an embodiment of the present invention.

FIG. 9 is a graph showing a relationship between duty and actual current according to the embodiment of the present invention.

[Explanation of symbols]

BP brake pedal, MC master cylinder HP hydraulic pump, RS reservoir Wfr, Wfl, Wrr, Wrl Wheel cylinder FR, FL, RR, RL wheels ECU electronic control unit

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Claims (8)

[Claims] 1. A linear solenoid drive control method for energizing a linear solenoid to drive a control means to control a controlled object by the control means, wherein a target current for the linear solenoid is set in accordance with a control status of the control means. Set the duty corresponding to the target current,
The linear solenoid is driven according to the duty, the energization current to the linear solenoid is detected, the energization current and the target current are compared, and the relationship between the duty and the target current is corrected according to the comparison result. A linear solenoid drive control method comprising: 2. The linear solenoid drive control method according to claim 1, wherein a predetermined current within a drive start limit is supplied to the linear solenoid even when the control means is not driven. 3. When correcting the relationship between the duty and the target current, at least one of an upper limit and a lower limit is applied to at least one of the duty and the target current. The linear solenoid drive control method according to claim 1. 4. A linear solenoid drive control device for energizing a linear solenoid to drive a control means, and controlling the controlled object by the control means, wherein a target current for the linear solenoid is set in accordance with the control status of the control means. A duty setting means for setting a duty corresponding to the target current, a current detecting means for detecting an energization current to the linear solenoid, and driving the linear solenoid in accordance with the duty set by the duty setting means. And an adjusting unit that compares the energizing current detected by the current detecting unit with the target current set by the duty setting unit and corrects the relationship between the duty and the target current according to the comparison result. Linear solenoid drive control device. 5. When the adjusting means determines that the energizing current is smaller than the target current when energizing the linear solenoid, the relationship between the duty and the target current is increased by the energizing current. 5. The linear solenoid drive according to claim 4, wherein the relationship between the duty and the target current is gradually corrected in a direction in which the energized current decreases when the linear solenoid is de-energized. Control device. 6. When the adjusting means determines that the energization current is larger than the target current when the linear solenoid is energized, the relationship between the duty and the target current is reduced in the direction in which the energization current decreases. 5. The linear solenoid drive control device according to claim 4, wherein the relationship between the duty and the target current is maintained even when the linear solenoid is not energized. 7. The adjusting means is configured to supply a predetermined current within a drive start limit to the linear solenoid even when the control means is not driven. The linear solenoid drive control device described. 8. When the adjusting means corrects the relationship between the duty and the target current, at least one of an upper limit and a lower limit is applied to at least one of the duty and the target current. 5. The linear solenoid drive control device according to claim 4, wherein the linear solenoid drive control device is configured as described above.