JP2010090978A - Current control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure desired responsiveness and follow-up property by alternately repetitively executing a duty control and a feedback control within a predetermined control period. <P>SOLUTION: The current control device 10 alternately repetitively executes the duty control for controlling a current carried to each of solenoid valves 12, 15, 32 and 35 driven by current control by a predetermined duty and the feedback control for matching the current to a target current within the predetermined control period, and prohibits, during execution of either one of the duty control and the feedback control, execution of the other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a current control device.

Conventionally, for example, in order to compensate for a current change due to heat generation of a coil of a solenoid valve when changing a pressure increase gradient of a brake fluid pressure by performing duty control with the energization of the solenoid valve being an intermediate state between on and off 2. Description of the Related Art A vehicle antilock brake control device that performs feedback control for causing a current supplied to a coil to follow a target current is known (see, for example, Patent Document 1).
Conventionally, for example, in current feedback control, the target current is set to prevent current overshoot, or feedback control is performed to prevent error accumulation when the target current becomes zero. A current control device for stopping is known (for example, see Patent Document 2).
JP 2004-196235 A JP 2002-182759 A

By the way, in the duty control of energization to the solenoid valve in the vehicle anti-lock brake control device according to the above prior art, the current feedback control of the current control device according to the above prior art is combined to achieve the target current or the target If the feedback control is stopped when the current becomes zero, there arises a problem that the responsiveness and followability in the current control are deteriorated. In other words, if the target current is made, the time required to converge the current supplied to the solenoid valve to the target current is lengthened, resulting in a decrease in responsiveness, and feedback control when the target current becomes zero. If the operation is stopped, the target current becomes non-zero, and the followability when the execution of the feedback control is resumed is deteriorated.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a current control device capable of ensuring desired responsiveness and followability.

  In order to solve the above problems and achieve the object, the current control device according to the first aspect of the present invention is a valve driven by current control (for example, each solenoid valve 12, 15, 32 in the embodiment). 35) and, as the current control, a duty control for controlling the current supplied to the valve with a predetermined duty and a feedback control for matching the current with a target current are repeatedly executed within a predetermined control period. Control means (for example, the current control unit 10a in the embodiment), and the control means prohibits the execution of one of the duty control and the feedback control during the execution of the other.

  According to the current control device according to the first aspect of the present invention, the duty control and the feedback control are repeatedly executed within a predetermined control period, so that it is possible to match the current supplied to the valve with the target current. Can be ensured. In addition, by prohibiting the execution of either one of the duty control and the feedback control, the current supplied to the valve is prevented from overshooting, and the feedback control is appropriately executed. For example, a desired response can be ensured as compared with a case where a target current is achieved or feedback control is temporarily stopped.

Hereinafter, a current control device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
The current control device 10 according to the present embodiment is provided, for example, in an antilock control device 80 that controls a vehicle brake device 80a shown in FIG.

  The brake device 80a includes a master cylinder 2 as a brake fluid pressure generator that generates brake fluid pressure by operating the brake pedal 1 by a driver. The master cylinder 2 includes, for example, each of the left front wheel FL and the right rear wheel RR. An output port 4 connected to the wheel cylinders 3a and 3b and an output port 5 connected to the wheel cylinders 3c and 3d of the right front wheel FR and the left rear wheel RL are provided.

The output port 4 of the master cylinder 2 and the wheel cylinders 3a and 3b of the left front wheel FL and the right rear wheel RR are connected by a connection path 11, and each wheel cylinder 3a and 3b is connected to the connection path 11 in parallel. The normally open solenoid valves 12 and 12 are inserted in the front.
Each wheel cylinder 3a, 3b and a reservoir 13 for releasing the brake fluid pressure in each wheel cylinder 3a, 3b are connected by a release path 14, and the release path 14 is parallel to each wheel cylinder 3a, 3b. Normally closed solenoid valves 15 and 15 are inserted.

  Brake fluid sent from the wheel cylinders 3a and 3b is stored in the reservoir 13, and this brake fluid is a return path in which a damper chamber 17 for absorbing pump pulsation provided upstream of the pump 16 and the pump 16 is inserted. 18 is returned to the master cylinder 2 side.

  Further, a check valve 19 that allows the brake fluid to flow from the wheel cylinders 3a, 3b to the master cylinder 2 side is provided in parallel with the normally open solenoid valve 12, and from the wheel cylinders 3a, 3b to the master cylinder 2 side. Check valves 20 and 21 that allow the brake fluid to flow are provided in series on the upstream side and the downstream side of the pump 16.

The output port 5 of the master cylinder 2 and the wheel cylinders 3c, 3d of the right front wheel FR and the left rear wheel RL are connected by a connection path 31, and the wheel cylinders 3c, 3d are parallel to the connection path 31. Normally-open type solenoid valves 32 and 32 are inserted in the front.
Each wheel cylinder 3c, 3d and a reservoir 33 for releasing the brake fluid pressure in each wheel cylinder 3c, 3d are connected by a release path 34, and the release path 34 is connected in parallel to each wheel cylinder 3c, 3d. Normally closed solenoid valves 35 and 35 are inserted.

  Brake fluid sent from the wheel cylinders 3c and 3d is stored in the reservoir 33, and this brake fluid is a return path in which a damper chamber 37 for absorbing pump pulsation provided upstream of the pump 36 and the pump 36 is inserted. 38 is returned to the master cylinder 2 side.

  In addition, a check valve 39 that allows the brake fluid to flow from the wheel cylinders 3c, 3d to the master cylinder 2 side is provided in parallel with the normally open solenoid valve 32, and from the wheel cylinders 3c, 3d to the master cylinder 2 side. Check valves 40 and 41 that allow the brake fluid to flow are provided in series on the upstream side and the downstream side of the pump 36.

The normally open solenoid valves 12 and 32 are in communication with each other by the elastic force of the return springs 12b and 32b when the solenoids 12a and 32a are not energized, and the brake fluid pressure of the master cylinder 2 increases the wheel cylinder pressure.
Further, when the solenoids 12a and 32a are energized, they are cut off against the elastic force of the return springs 12b and 32b, and the wheel cylinder pressure is maintained.

  The normally closed solenoid valves 15 and 35 are cut off by the elastic force of the return springs 15b and 35b when the solenoids 15a and 35a are not energized. When the solenoids 15a and 35a are energized, the solenoids 15a and 35b are in communication with each other against the elastic force of the return springs 15b and 35b. The pressure is reduced.

The normally open solenoid valves 12 and 32 are normally opened at a normal position where no current is applied, and are moved to a closed state at a switching position by energization. The normally closed solenoid valves 15 and 35 are normally closed at a normal position where no current is supplied. The reason for shifting to the open state at the switching position by energization is because of the so-called fail-safe relationship in the case of abnormal operation compensation.
In the normally open solenoid valves 12 and 32, when the brake fluid pressure works from the master cylinder 2 side via the connection paths 11 and 31, the brake fluid pressure is in the same direction as the urging direction of the return springs 12b and 32b. That is, it acts in the direction leading to the open state.

The normally open solenoid valves 12 and 32, the normally closed solenoid valves 15 and 35, and the motors (not shown) for driving the pumps 16 and 36 are controlled by an antilock control device 80.
The antilock control device 80 is output from each wheel speed sensor 46 that detects each speed (each wheel speed VW (j); j = 1,..., 4) of the left and right front wheels FL and FR and the rear wheels RL and RR. Based on the detected signal, it is detected whether or not each wheel FL, FR, RL, RR has a locking tendency, and the brake fluid pressure of each wheel cylinder 3a, 3b, 3c, 3d is determined according to the detection result. The decompression mode in which the normally open solenoid valves 12 and 32 are closed and the normally closed solenoid valves 15 and 35 are opened, and the normally open solenoid valves 12 and 32 are closed and the normally closed types are closed. Either a holding mode in which the solenoid valves 15 and 35 are closed, or a pressure increasing mode in which the normally open solenoid valves 12 and 32 are opened and the normally closed solenoid valves 15 and 35 are closed ( (ABS control mode).

  As shown in FIG. 2, for example, the antilock control device 80 includes a control device 80b, a wheel speed sensor 46, and a brake torque sensor 47. The control device 80b includes a target torque calculation unit 51, a torque A deviation calculation unit 52 and a valve control unit 53 are provided. The current control device 10 is provided in the valve control unit 53.

  The target torque calculation unit 51 is output from each wheel speed sensor 46 that detects each speed (each wheel speed VW (j); j = 1,..., 4) of the left and right front wheels FL, FR and rear wheels RL, RR. Detection signals output from the respective brake torque sensors 47 for detecting the brake torque T (T (j); j = 1,..., 4) acting on the left and right front wheels FL, FR and the rear wheels RL, RR. Based on the signal, the target brake torque Tt of each wheel is calculated.

  The torque deviation calculation unit 52 is configured to generate a brake torque deviation (Tt) between the target brake torque Tt of each wheel output from the target torque calculation unit 51 and the detection signal of the brake torque T of each wheel output from each brake torque sensor 47. -T) is calculated.

When the anti-lock control device 80 selects execution of any one of the pressure reducing mode, the holding mode, and the pressure increasing mode, the valve control unit 53 selects each electromagnetic valve 12, 15 corresponding to the selected mode. , 32 and 35 are controlled.
Furthermore, the valve control unit 53 sets each brake electromagnetic deviation (Tt-T) to zero based on the brake torque deviation (Tt-T) of each wheel output from the torque deviation calculation unit 52, for example. The brake fluid pressure of each wheel cylinder 3a, 3b, 3c, 3d is controlled by opening and closing the valves 12, 15, 32, 35.

The valve control unit 53 includes a current control device 10 that controls a current supplied to each electromagnetic valve 12, 15, 32, 35.
The current control device 10 includes a current control unit 10a and electromagnetic valves 12, 15, 32, and 35. The current control unit 10a sets a target current according to the brake torque deviation (Tt-T) and reduces the pressure. In accordance with any mode selected from the mode, the holding mode, and the pressure increasing mode, feedback control is performed so that the current supplied to each solenoid valve 12, 15, 32, 35 matches the target current.
Further, the current control unit 10a executes duty control for controlling the current supplied to each solenoid valve 12, 15, 32, 35 with a predetermined duty.

For example, as shown in FIGS. 3 and 4, the pressure increasing mode for increasing the brake fluid pressure of each wheel cylinder 3a, 3b, 3c, 3d in the ABS control mode includes a normal pressure increasing mode and a slow pressure increasing mode. Can be selected.
In the normal pressure increasing mode, each solenoid valve 12, over a period of a driving time T1 including, for example, a minimum time during which each solenoid valve 12, 15, 32, 35 can operate, for each predetermined control cycle T2. ON / OFF control in which only one of ON and OFF of energization to 15, 32, and 35 is maintained is executed by the current control unit 10a, and the brake fluid pressure of each wheel cylinder 3a, 3b, 3c, 3d is controlled. It increases in a step shape every period T2.

Further, in the slow pressure increasing mode, a pulse width T3 (for example, T3 = (predetermined PWM cycle (PWMCL)) corresponding to a predetermined duty (Duty) over the period of the driving time T1 every predetermined control cycle T2. Only duty control in which energization of each solenoid valve 12, 15, 32, 35 is alternately turned on and off alternately is executed at × Duty, and after the execution of this duty control is completed, a subsequent period (that is, ( Only the feedback control is executed by the current control unit 10a over the period T2-T1). That is, when the current control unit 10a repeatedly executes the duty control and the feedback control within the predetermined control cycle T2, the current control unit 10a executes either one of the duty control and the feedback control. Ban.
As a result, the brake fluid pressure in each of the wheel cylinders 3a, 3b, 3c, 3d changes in a gradual increasing trend over the period of the drive time T1 in which only the duty control is executed, and the period in which only the feedback control is executed. (That is, constant during (T2-T1) period).

  The antilock control device 80 according to the present embodiment has the above-described configuration. Next, the operation of the antilock control device 80 will be described.

First, for example, in step S01 shown in FIG. 5, on the basis of detection signals output from the wheel speed sensors 46, the speeds of the left and right front wheels FL, FR and rear wheels RL, RR (each wheel speed VW (j); j = 1,..., 4) are acquired.
Next, in step S02, the slip ratio of each wheel is calculated.
Next, in step S03, it is detected whether or not each wheel FL, FR, RL, RR has a locking tendency, and each normally open type electromagnetic valve 12, 32 is closed according to the detection result. Depressurization mode for opening each normally closed solenoid valve 15, 35, holding mode for closing each normally open solenoid valve 12, 32 and closing each normally closed solenoid valve 15, 35, One mode (ABS control mode) is selected from the pressure increasing mode in which the open solenoid valves 12 and 32 are opened and the normally closed solenoid valves 15 and 35 are closed.

Next, in step S04, the target brake torque Tt of each wheel FL, FR, RL, RR is calculated.
Next, in step S05, the actual brake torque T of each wheel FL, FR, RL, RR is acquired.
Next, in step S06, the brake torque deviation (Tt-T) of each wheel FL, FR, RL, RR is calculated.

Next, in step S07, for each wheel FL, FR, RL, RR, each solenoid valve 12, 15, 32, 35 is selected according to the selected ABS control mode and brake torque deviation (Tt-T). The brake fluid pressure in each of the wheel cylinders 3a, 3b, 3c, 3d is controlled by opening and closing and the process proceeds to return.
In this step S07, for example, when the slow pressure increasing mode is selected as the pressure increasing mode, for example, at a predetermined control cycle T2, first, for example, the minimum time during which each solenoid valve 12, 15, 32, 35 can be operated. Only duty control in which the energization of the solenoid valves 12, 15, 32, and 35 is alternately turned on and off with a pulse width T3 corresponding to a predetermined duty is executed over the period of the drive time T1 including the above. After the execution of the duty control is completed, only the feedback control is executed over the subsequent period (that is, the period of (T2-T1)).

  As described above, according to the current control device 10 according to the present embodiment, the duty control and the feedback control are repeatedly executed within the predetermined control cycle T2 in the slow pressure increasing mode. , 15, 32, and 35, it is possible to ensure desired followability when the current supplied to the target current is matched. In addition, by prohibiting the execution of either one of the duty control and the feedback control, the current supplied to each solenoid valve 12, 15, 32, 35 is prevented from overshooting. Thus, the feedback control can be properly executed, and, for example, desired response can be ensured as compared with the case where the target current is achieved or the feedback control is temporarily stopped.

  In the above-described embodiment, only the duty control is executed first and then only the feedback control is executed every predetermined control cycle T2 in the slow pressure increasing mode. However, the present invention is not limited to this. First, only the feedback control may be executed, and then only the duty control may be executed.

  In the above-described embodiment, when the duty control and the feedback control are repeatedly executed within the control cycle T2 in the slow pressure increasing mode among the pressure increasing modes, either the duty control or the feedback control is performed. While the execution of either one is prohibited during the execution of one, the present invention is not limited to this. In other ABS control modes, when the duty control and the feedback control are repeatedly executed within the control cycle T2, the duty is The execution of either one of the control and the feedback control may be prohibited during the execution of either one.

  In the above-described embodiment, the target torque calculation unit 51 calculates the target brake torque Tt of each wheel based on the detection signal of the brake torque T of each wheel output from each brake torque sensor 47. For example, as in the modification of the above-described embodiment shown in FIG. 6, each brake torque sensor 47 is omitted, and instead, the brake hydraulic pressure of each wheel cylinder 3 a, 3 b, 3 c, 3 d is set. Each of the hydraulic pressure sensors 48 to detect is provided, and the target torque calculation unit 51 is configured to detect the target of each wheel based on the detection signal of the brake hydraulic pressure of each wheel cylinder 3a, 3b, 3c, 3d output from each hydraulic pressure sensor 48. The brake torque Tt may be calculated.

It is a block diagram of the brake device which concerns on the anti-lock control apparatus which concerns on embodiment of this invention. It is a block diagram of the anti-lock control apparatus by this Embodiment. It is a graph which shows the example of the change of the brake fluid pressure in the normal pressure increase mode and slow pressure increase mode which concern on the anti-lock control apparatus by this Embodiment. It is a figure which shows the example of the drive pattern of each solenoid valve in the normal pressure increase mode and slow pressure increase mode which concern on the anti-lock control apparatus by this Embodiment. It is a flowchart which shows operation | movement of the anti-lock control apparatus by this Embodiment. It is a block diagram of the anti-lock control apparatus which concerns on the modification of this Embodiment.

Explanation of symbols

10 Current Control Device 10a Current Control Unit (Control Unit)
12, 32 Normally open solenoid valve (valve)
15, 35 Normally closed solenoid valve (valve)
80 Anti-lock control device 80a Brake device 80b Control device 46 Wheel speed sensor 47 Brake torque sensor 48 Hydraulic pressure sensor

Claims (1)

A valve driven by current control;
As the current control, there is provided control means for repeatedly executing a duty control for controlling a current supplied to the valve with a predetermined duty and a feedback control for making the current coincide with a target current within a predetermined control period. ,
The current control device is characterized in that the control means prohibits the execution of either one of the duty control and the feedback control.

Images