WO2014013972A1

WO2014013972A1 - Parking brake control device

Info

Publication number: WO2014013972A1
Application number: PCT/JP2013/069258
Authority: WO
Inventors: 雅敏半澤; 賢太郎湯浅; 崇裕白木
Original assignee: 株式会社アドヴィックス
Priority date: 2012-07-16
Filing date: 2013-07-16
Publication date: 2014-01-23
Also published as: JP2014019235A

Abstract

[Problem] To enable detection of an abnormality showing only a relatively small change in current value, such as abnormal gain of an amplifier, such that actions to correct the abnormality can be taken. [Solution] Changes in a motor current value in three regions, namely, an inrush current period, a no-load current period, and a current rise period, under normal circumstances are pre-stored as normative values, and an abnormality is detected by comparing the normative values with the present value of the motor current detected when EPB is used. When an abnormality is detected, a correction is made to increase a locking operation time by setting a target current value to be larger than a value that is set under normal circumstances, for example. Consequently, even in the presence of an abnormality, locking control can be properly carried out, so the EPB does not need to be stopped. Therefore, an abnormality that appears only in the form of a relatively small change in current value such as abnormal gain of an amplifier can be detected, and an action to correct the abnormality can be taken.

Description

Parking brake control device

The present invention relates to an EPB control device applied to a vehicle brake system having an electric parking brake (hereinafter referred to as EPB (Electric parking) brake).

In the case of an EPB for a vehicle, for example, when an abnormality such as cutting of a cable for driving the EPB occurs, the EPB cannot be operated, so that it is desired to be able to detect this immediately.

For this reason, Patent Document 1 proposes a technique for determining an EPB abnormality by calculating a current change amount during EPB operation and comparing the current change amount with a predetermined threshold value indicating a normal range. Has been. Specifically, as shown in FIG. 27, when the motor current value is monitored and the current change amount is calculated, and the current change amount exceeds a normal threshold uniquely determined by the motor characteristics and the rigidity of the friction part, the cable It is detected that an abnormality such as motor lock due to disconnection has occurred. Patent Document 2 proposes a technique for monitoring a motor current value during operation of an EPB and detecting an abnormality by comparing a threshold value indicating a normal range with an actual value.

JP 2003-2186 A JP 2004-314756 A

However, the technique disclosed in Patent Document 1 can detect abnormalities that show a large change in current value, such as disconnection of a cable for driving an EPB and adhesion of an operating part of the EPB, but a current monitor amplifier circuit ( Hereinafter, it is impossible to detect an abnormality in which only a relatively small change in current value is caused to the extent that the performance or function is reduced, such as a gain abnormality in an amplifier). That is, only the occurrence of an abnormality that shows a large current value change can be detected. Then, abnormality determination is performed based on the current differential value that is the current change amount at each moment, and an abnormality that slightly deviates from the threshold value is not detected. Such as noise and the catch of the working part of the EPB are included temporarily and have no problem in use. In order to prevent such a phenomenon from being judged as abnormal, it is necessary to reduce the sensitivity by providing a filter or widening the threshold range, so it is difficult to detect abnormalities that show only a small current value change. I have to. Even if an abnormality can be detected, what kind of abnormality cannot be specified cannot be linked to the subsequent treatment.

Further, in the technique disclosed in Patent Document 2, the region in which the determination can be performed as in Patent Document 1 is not limited to the operation region in which the motor current value is increasing. However, the abnormality judgment is performed using the motor current value itself, and the abnormality is based on the maximum current (restraint current) when the motor is locked and the minimum current (no load current) when the motor is driven in a no-load state. Since only the determination is performed, it is possible to determine only an abnormality such as a malfunction indicating an abnormal value that is not possible originally, a disconnection or short circuit of the cable, or an adhesion of the working part of the EPB.

In view of the above points, an object of the present invention is to provide an EPB control device that can detect an abnormality that shows only a relatively small current value change, such as an amplifier gain abnormality, and can take measures against the abnormality.

In order to achieve the above object, according to the first aspect of the present invention, the reference value setting means (115 to 125) changes the motor current value during the lock control for setting the reference value at the start of the lock control. It is divided into three areas: the inrush current, the no-load current that becomes a constant value after the inrush current, and the current rise that rises from the no-load current, and the descending slope of the motor current value at the inrush current Current descent norms that serve as reference values for motors, no-load current norms that serve as reference values for motor current values at no-load current, and current up-gradient norms that serve as reference values for motor current values that rise when current increases And are set. Then, when the lock control is executed when the wheels are actually locked by the abnormality determination means (155 to 165), the motor current value is decreased during the inrush current based on the motor current value during the lock control. The current descending slope that becomes the gradient, the no-load current value that becomes the motor current value at the time of no-load current, and the current rising slope that becomes the increasing slope of the motor current value when the current rises are calculated. A gain abnormality is determined by comparing the slope with the current descending slope norm, comparing the no-load current value with the no-load current norm, and comparing the current rising gradient with the current ascending norm. Then, the correction means (250) corrects the lock operation time which is the time during which the electric motor (10) is operated.

In this way, changes in the motor current value in the three regions at the time of inrush current at normal time, at no load current, and at the time of current rise are stored as reference values, which are stored as motor currents when EPB (2) is used. An abnormality is detected by comparing with the current value, and when an abnormality is detected, the lock operation time is corrected by the correction means (250). As a result, even when there is an abnormality, it is possible to appropriately perform the lock control, so that it is not necessary to stop the EPB (2). Therefore, it is possible to detect not only failures such as cable breaks and short circuits, mechanical damage of EPB (2), but also abnormalities that show only a relatively small change in current value, such as amplifier gain abnormalities. Can be done.

For example, as described in claim 2, in the norm setting means (115 to 125), at least the current rising gradient norm is memorized by executing the lock control at a normal time before the friction material (11) is worn. Or set as a constant at the time of design, and in the abnormality determination means (155 to 165), the current descending gradient is larger than the current descending gradient norm, the no-load current value is larger than the no-load current value norm, or , Gain abnormality due to current rising gradient larger than current rising gradient norm, current falling gradient smaller than current falling gradient norm, no load current value smaller than no load current norm, or current rising gradient current rising Whether the gain is abnormal due to being smaller than the gradient criterion can be determined. In this case, the correction means (250) performs a correction to increase the lock operation time when the abnormality determination means (155 to 165) determines that the gain is abnormal due to a large value, and locks when it is determined that the gain is abnormal due to a small value. What is necessary is just to make correction | amendment which shortens an operating time.

In addition, as described in claim 3, the norm setting means (115 to 125) stores at least the current rising gradient norm by executing lock control at the time of abnormality after the friction material (11) is worn. Or it can be set as a constant at the time of design.

The invention according to claim 4 further comprises display instruction means for displaying that a gain abnormality has occurred to the notification device (27) when the abnormality determination means (155 to 165) determines that a gain abnormality has occurred. It is characterized by having.

In this way, the driver may be informed that a gain abnormality has occurred through the notification device (27). Thereby, the driver can grasp that the gain abnormality has occurred, and can take measures such as repair of the amplifier.

According to the fifth aspect of the present invention, the wear determination means (180) for determining the wear of the friction material (11) is provided, and the wear determination means (180) is a current set by the standard value setting means (125). Ascending slope norm is set to a value that takes into account variations due to wear of the friction material (11), and a current ascending slope norm with a value that does not take into account variations due to wear is set, and the abnormality determining means (155) determines that there is no gain abnormality. When it is determined, it is determined whether or not the gain is abnormal by comparing the current increasing gradient with a current increasing gradient standard that does not take into account variations due to wear. If it is determined that the gain is abnormal, the friction material (11) It is characterized in that it is determined that the wear of the material has occurred.

In this way, it is possible to determine the wear of the friction material (11). When it is detected that the friction material (11) is worn, the driver can take measures such as replacing the friction material (11) by notifying the driver, for example.

In the invention described in claim 6, the reference value setting means (125) includes the first current increase gradient reference and the second current increase gradient in at least two different periods (T1 ′, T2 ′) as the current increase gradient reference. A standard is set, and the abnormality determination means (165) corresponds to each of the first and second current increase gradient standards when the current rises based on the motor current value during the lock control when the wheel is actually locked. The first and second current rising gradients that are current rising gradients in the period (T1, T2) are calculated, and the first and second current rising gradients are compared with the first and second current rising gradient norms, respectively. By doing so, it is characterized by determining a gain abnormality.

In this way, abnormality detection at the time of current rise can be performed with at least two abnormality detection timings. As a result, it is possible to reduce the influence of a change in gradient according to the characteristics of EPB (2), and it is possible to detect an abnormality regardless of the characteristics of EPB (2).

In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a schematic diagram showing an overall outline of a vehicle brake device according to a first embodiment of the present invention. It is a cross-sectional schematic diagram of the brake mechanism of the rear-wheel system with which a brake device for vehicles is equipped. 6 is a timing chart showing changes in the monitor value of the motor current value during lock control in normal cases and when gain is abnormal due to an amplifier failure or the like. It is a whole flowchart of the parking brake control process concerning release operation | movement. It is a flowchart of a lock control process. 6 is a map showing a relationship between a target braking force and a target motor current value increase amount TMIUP. It is the map which showed the relationship between M / C pressure and the subtraction value IDOWN. It is a comparison figure of the motor current value at the time of inrush current. It is the flowchart which showed the detail of the current descent | fall gradient norm setting process at the time of inrush current. It is a comparison figure of the motor current value at the time of no load current. It is the flowchart which showed the detail of the no load current value norm setting process at the time of no load current. It is a comparison figure of the motor current value at the time of current rise. It is the flowchart which showed the detail of the electric current climb gradient norm setting process at the time of an electric current rise. It is the flowchart which showed the detail of lock release display processing. It is the flowchart which showed the detail of the current descent gradient abnormality determination process at the time of inrush current. It is the flowchart which showed the detail of the no load current value abnormality determination process at the time of no load current. It is the flowchart which showed the detail of the current climb gradient abnormality determination process at the time of current rise. It is a flowchart of a release control process. It is a whole flowchart of the parking brake control process in connection with release operation | movement demonstrated in 2nd Embodiment of this invention. It is the figure which showed the relationship between the actual electric current value which is actually going to output as a motor electric current value, and a monitor value. It is the flowchart which showed the detail of the pad abrasion determination process. It is a comparison figure of the motor electric current value at the time of the electric current rise at the time of normal and the gain abnormality by amplifier failure. It is the figure which showed the change of the motor electric current value when the voltage fluctuation (voltage rise) of a drive power supply arises. It is a comparison figure of the motor current value at the time of a current rise when the brake pad is worn (at the time of abnormality) and normal. It is the flowchart which showed the detail of the electric current climb gradient norm setting process at the time of an electric current rise. It is the flowchart which showed the detail of the current climb gradient abnormality determination process at the time of current rise. It is the timing chart which showed the method of the conventional abnormality determination.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described. In the present embodiment, a vehicle brake device in which a disc brake type EPB is applied to the rear wheel system will be described as an example. FIG. 1 is a schematic diagram showing an overall outline of a vehicle brake device according to the present embodiment. FIG. 2 is a schematic sectional view of a rear-wheel brake mechanism provided in the vehicle brake device. Hereinafter, description will be given with reference to these drawings.

As shown in FIG. 1, the vehicular brake device includes a service brake 1 that generates a service brake force based on a driver's stepping force and an EPB 2 that regulates the movement of the vehicle during parking.

The service brake 1 is a hydraulic brake mechanism that generates a brake hydraulic pressure based on depression of the brake pedal 3 by a driver and generates a service brake force based on the brake hydraulic pressure. Specifically, the service brake 1 boosts the pedaling force according to the depression of the brake pedal 3 by the driver with the booster 4, and then applies the brake fluid pressure according to the boosted pedaling force to the master cylinder (hereinafter referred to as the master cylinder). , M / C). Then, the brake fluid pressure is transmitted to a wheel cylinder (hereinafter referred to as W / C) 6 provided in the brake mechanism of each wheel, thereby generating a service brake force. In addition, an actuator 7 for controlling the brake fluid pressure is provided between the M / C 5 and the W / C 6, and various types for improving the safety of the vehicle by adjusting the service brake force generated by the service brake 1. The structure is such that control (for example, anti-skid control) can be performed.

Various controls using the actuator 7 are executed by an ESC (Electronic Stability Control) -ECU 8 that controls the service brake force. For example, by outputting a control current for controlling various control valves (not shown) provided in the actuator 7 and a motor for driving the pump from the ESC-ECU 8, the hydraulic circuit provided in the actuator 7 is controlled, and the W / C 6 The W / C pressure transmitted to is controlled. Thereby, avoidance of wheel slip is performed, and the safety of the vehicle is improved. For example, the actuator 7 is a pressure increase control that controls whether the brake fluid pressure generated in the M / C5 or the brake fluid pressure generated by the pump drive is applied to the W / C6 for each wheel. It is equipped with a valve, a pressure reduction control valve that reduces the W / C pressure by supplying brake fluid in each W / C 6 to the reservoir, and is configured to increase, hold, and control the pressure reduction. ing. In addition, the actuator 7 can realize the automatic pressurizing function of the service brake 1, and automatically applies W / C6 even when there is no brake operation based on the pump drive and control of various control valves. It is possible to press. Since the configuration of the actuator 7 has been conventionally known, the details are omitted here.

On the other hand, the EPB 2 generates a parking brake force by controlling the brake mechanism with the motor 10 and has an EPB control device (hereinafter referred to as EPB-ECU) 9 for controlling the driving of the motor 10. Has been.

The brake mechanism is a mechanical structure that generates a braking force in the vehicle brake device according to the present embodiment, and the front wheel brake mechanism is configured to generate a service brake force by operating the service brake 1. The wheel system brake mechanism has a common structure for generating a braking force for both the operation of the service brake 1 and the operation of the EPB 2. Since the front-wheel brake mechanism is a brake mechanism that is generally used from the past without a mechanism that generates a parking brake force based on the operation of the EPB 2 with respect to the rear-wheel brake mechanism, The description is omitted, and in the following description, a rear wheel brake mechanism will be described.

In the rear wheel brake mechanism, not only when the service brake 1 is operated but also when the EPB 2 is operated, the brake pad 11 which is a friction material shown in FIG. By sandwiching the brake disk 12, a frictional force is generated between the brake pad 11 and the brake disk 12 to generate a braking force.

Specifically, the brake mechanism rotates the motor 10 directly fixed to the body 14 of the W / C 6 for pressing the brake pad 11 as shown in FIG. 2 in the caliper 13 shown in FIG. Thus, the spur gear 15 provided on the drive shaft 10a of the motor 10 is rotated. And the brake pad 11 is moved by transmitting the rotational force (output) of the motor 10 to the spur gear 16 meshed with the spur gear 15, and the parking brake force by EPB2 is generated.

In the caliper 13, in addition to the W / C 6 and the brake pad 11, a part of the end surface of the brake disk 12 is accommodated so as to be sandwiched between the brake pads 11. The W / C 6 can generate a W / C pressure in the hollow portion 14a which is a brake fluid storage chamber by introducing the brake fluid pressure into the hollow portion 14a of the cylindrical body 14 through the passage 14b. In the hollow portion 14a, the rotary shaft 17, the propulsion shaft 18, the piston 19 and the like are provided.

The rotating shaft 17 is connected to the spur gear 16 at one end through an insertion hole 14 c formed in the body 14. When the spur gear 16 is rotated, the rotating shaft 17 is rotated with the rotation of the spur gear 16. A male screw groove 17 a is formed on the outer peripheral surface of the rotary shaft 17 at the end of the rotary shaft 17 opposite to the end connected to the spur gear 16. On the other hand, the other end of the rotating shaft 17 is pivotally supported by being inserted into the insertion hole 14c. Specifically, the insertion hole 14c is provided with a bearing 21 together with an O-ring 20 so that the brake fluid does not leak through the O-ring 20 between the rotary shaft 17 and the inner wall surface of the insertion hole 14c. However, the bearing 21 supports the other end of the rotating shaft 17.

The propulsion shaft 18 is constituted by a nut made of a hollow cylindrical member, and a female screw groove 18a that is screwed with the male screw groove 17a of the rotary shaft 17 is formed on the inner wall surface. The propulsion shaft 18 is configured in a columnar shape or a polygonal column shape having a key for preventing rotation, for example, so that even if the rotation shaft 17 is rotated, the propulsion shaft 18 is rotated around the rotation center of the rotation shaft 17. It has no structure. For this reason, when the rotating shaft 17 is rotated, the rotational force of the rotating shaft 17 is changed to a force for moving the propulsion shaft 18 in the axial direction of the rotating shaft 17 due to the engagement between the male screw groove 17a and the female screw groove 18a. Convert. When the driving of the motor 10 is stopped, the propulsion shaft 18 stops at the same position due to the frictional force generated by the engagement between the male screw groove 17a and the female screw groove 18a, resulting in a target parking brake force. If the driving of the motor 10 is stopped at that time, the propulsion shaft 18 is held at that position, and a desired parking brake force can be held and self-locking can be performed.

The piston 19 is disposed so as to surround the outer periphery of the propulsion shaft 18, is configured by a bottomed cylindrical member or a polygonal cylindrical member, and the outer peripheral surface is in contact with the inner wall surface of the hollow portion 14 a formed in the body 14. Are arranged as follows. A structure in which a seal member 22 is provided on the inner wall surface of the body 14 and W / C pressure can be applied to the end surface of the piston 19 so as not to cause brake fluid leakage between the outer peripheral surface of the piston 19 and the inner wall surface of the body 14. It is said that. The seal member 22 is used to generate a reaction force for pulling back the piston 19 during release control after lock control. Since the seal member 22 is provided, basically, even if the brake pad 11 and the piston 19 are pushed in by the brake disc 12 inclined during turning within a range not exceeding the elastic deformation amount of the seal member 22, they are braked. It can be pushed back to the disc 12 side so that the gap between the brake disc 12 and the brake pad 11 is held with a predetermined clearance.

When the propulsion shaft 18 is provided with a key for preventing rotation so that the piston 19 is not rotated about the rotation center of the rotation shaft 17 even if the rotation shaft 17 rotates, the key is When a sliding keyway is provided and the propulsion shaft 18 has a polygonal column shape, it has a polygonal cylindrical shape with a corresponding shape.

The brake pad 11 is disposed at the tip of the piston 19, and the brake pad 11 is moved in the left-right direction on the paper surface as the piston 19 moves. Specifically, the piston 19 can move to the left in the drawing as the propulsion shaft 18 moves, and at the end of the piston 19 (the end opposite to the end where the brake pad 11 is disposed). By applying the W / C pressure, it is configured to be movable in the left direction on the paper surface independently of the propulsion shaft 18. When the propulsion shaft 18 is in a release position (a state before the motor 10 is rotated), which is a standby position when the propulsion shaft 18 is in a normal release state, the brake fluid pressure in the hollow portion 14a is not applied (W / C). If pressure = 0), the piston 19 is moved to the right in the drawing by the elastic force of the seal member 22 described later, so that the brake pad 11 can be separated from the brake disk 12. Further, when the motor 10 is rotated and the propulsion shaft 18 is moved leftward from the initial position, even if the W / C pressure becomes zero, the propulsion shaft 18 that has moved moves the piston 19 rightward on the paper surface. The brake pad 11 is held at that location.

In the brake mechanism configured as described above, when the service brake 1 is operated, the piston 19 is moved to the left in the drawing based on the W / C pressure generated thereby, so that the brake pad 11 is brake disc. 12 to generate a service brake force. Further, when the EPB 2 is operated, the spur gear 15 is rotated by driving the motor 10, and the spur gear 16 and the rotating shaft 17 are rotated accordingly, so that the male screw groove 17a and the female screw groove 18a are rotated. The propulsion shaft 18 is moved to the brake disk 12 side (left direction in the drawing) based on the meshing of the two. Accordingly, the tip of the propulsion shaft 18 abuts against the bottom surface of the piston 19 to press the piston 19, and the piston 19 is also moved in the same direction, whereby the brake pad 11 is pressed against the brake disk 12, and the parking brake force Is generated. For this reason, it becomes possible to set it as the common brake mechanism which generate | occur | produces braking force with respect to both operation of the service brake 1 and operation of EPB2.

In such a brake mechanism, when the EPB 2 is operated, the W / C pressure is 0 and the brake pad 11 is not pressed against the brake disc 12 or the service brake 1 is operated. Even if the W / C pressure is generated, when the propulsion shaft 18 is in a state before contacting the piston 19, the load applied to the propulsion shaft 18 is reduced, and the motor 10 is driven in a substantially no-load state. When the brake disc 12 is pressed by the brake pad 11 while the propulsion shaft 18 is in contact with the piston 19, the parking brake force by the EPB 2 is generated, and a load is applied to the motor 10, and the load The value of the motor current that flows to the motor 10 changes according to the magnitude of the motor. For this reason, the generation state of the parking brake force by EPB2 can be confirmed by confirming the motor current value.

The EPB-ECU 9 is constituted by a known microcomputer having a CPU, ROM, RAM, I / O, etc., and performs parking brake control by controlling the rotation of the motor 10 according to a program stored in the ROM. It is. This EPB-ECU 9 corresponds to the parking brake control device of the present invention.

The EPB-ECU 9 inputs, for example, a signal corresponding to the operation state of an operation switch (SW) 23 provided in an instrument panel (not shown) in the vehicle interior, and turns the motor 10 in accordance with the operation state of the operation SW 23. To drive. Further, the EPB-ECU 9 performs lock control, release control, and the like based on the motor current value, the lock control is being performed based on the control state, the wheel is in the locked state by the lock control, and The vehicle knows that the release control is in progress and that the wheel is in the release state (EPB release state). Then, the EPB-ECU 9 outputs a signal indicating whether or not the wheel is locked to the lock / release indicator lamp 24 provided on the instrument panel according to the driving state of the motor 10. .

The vehicle brake device configured as described above basically performs an operation of generating a braking force on the vehicle by generating a service brake force by the service brake 1 when the vehicle travels. In addition, when the vehicle is stopped by the service brake 1, the driver presses the operation SW 23 to operate the EPB 2 to generate the parking brake force, thereby maintaining the stopped state, and then releasing the parking brake force. Perform the action. That is, as an operation of the service brake 1, when a driver operates a brake pedal during vehicle travel, the brake fluid pressure generated in the M / C 5 is transmitted to the W / C 6 to generate a service brake force. The operation of the EPB 2 is to move the piston 19 by driving the motor 10 and generate a parking brake force by pressing the brake pad 11 against the brake disc 12 to lock the wheel, By releasing the brake disc 12, the parking brake force is released and the wheel is released.

Specifically, parking brake force is generated or released by lock / release control. In the lock control, the EPB 2 is operated by rotating the motor 10 forward, and the rotation of the motor 10 is stopped at a position where a desired parking brake force can be generated by the EPB 2, and this state is maintained. Thereby, a desired parking brake force is generated. In release control, EPB2 is operated by rotating motor 10 reversely, and the parking brake force generated in EPB2 is released.

Subsequently, specific parking brake control executed by the EPB-ECU 9 in accordance with a program stored in the various functional units and a built-in ROM (not shown) using the brake system configured as described above will be described.

First, prior to description of specific parking brake control, the concept of abnormality detection executed in parking brake control will be described with reference to FIG. FIG. 3 is a timing chart showing an example of changes in the monitor value of the motor current value during lock control in each case when the gain is abnormal due to a failure of the amplifier or the like.

Since the load is not applied to the motor 10 at the beginning of the lock control, a constant no-load current flows in the no-load state after an inrush current is generated at the start of the lock control. Thereafter, when the brake pad 11 contacts the brake disk 12 and a load is applied to the motor 10, the motor current value gradually increases according to the load. When the gain is abnormal due to an amplifier failure or the like, for example, the motor current value is larger at the time of inrush current, no load current, and current rise than at normal time.

Therefore, the change of the motor current value in the three areas at the time of inrush current, no-load current at normal time, and current rise is stored as a reference value, which is used as the current value of the motor current value when using EPB2. Abnormality detection is performed by comparison. For example, in the example shown in FIG. 3, at the time of inrush current, the descending gradient of the motor current value is larger in the abnormal time than in the normal time. At the time of no load current, the magnitude of the motor current value is larger at the time of abnormality than at normal time. When the current rises, the rising slope of the motor current value becomes larger when the abnormality is greater than when it is normal.

異常 Anomaly detection is performed based on this, and when an anomaly is detected, a corresponding action is taken. For example, as shown in FIG. 3, when an abnormality is detected when the current rises, it indicates that an abnormality has occurred by turning on an abnormality detection flag. In an abnormal state, for example, a target motor current value (hereinafter referred to as a target current value) is reached earlier than in a normal state, so that the lock operation time is shortened. Therefore, the lock operation time is corrected to be increased. . For example, the lock operation time is corrected to be longer by setting the target current value to be larger than the value set during normal operation. As a result, even when there is an abnormality, it is possible to appropriately perform the lock control, and it is possible to avoid stopping the EPB 2.

Based on the above concept, the parking brake control of this embodiment is executed. Hereinafter, details of the parking brake control of the present embodiment will be described. FIG. 4 is an overall flowchart of the parking brake control process executed by the EPB-ECU 9. This process is executed for every predetermined control cycle during a period in which the ignition switch is turned on, for example.

First, in step 100, it is determined whether or not it is an initial shipment time. Assuming that the initial shipment time is normal, this determination is performed to store the change in motor current value in three regions at the time of inrush current, no load current, and current rise as a reference value. . A flag to that effect is set until the first parking brake control process is executed for the first time, and by checking the state of this flag, it can be determined whether or not it is the initial shipment time. It has become.

If a positive determination is made here, the routine proceeds to step 105, where it is determined whether or not there is a lock request, for example, whether or not the operation SW 23 is turned on. The state in which the operation SW 23 is on means that the driver is operating the EPB 2 to make it locked. For this reason, if an affirmative determination is made in this step, the process proceeds to step 110 and lock control is executed. Details of the lock control will be described with reference to a flowchart of the lock control process shown in FIG.

In the lock control process, the EPB 2 is operated by rotating the motor 10, the rotation of the motor 10 is stopped at a position where a desired braking force can be generated by the EPB 2, and this state is maintained. Since the change in the motor current value in the lock control at the time of initial shipment is assumed to be a change in the normal state, the lock control process is performed once in order to obtain each reference value.

First, in step 200, it is determined whether or not the flag FIUPS is turned off when the current value starts to increase. The current value increase start flag FIUPS is a flag that is turned on when the motor current value starts to increase, and is off until it is turned on in step 225 described later. If a positive determination is made here, the routine proceeds to step 205.

In step 205, the target motor current value increase amount TMIUP is set. The target motor current value increase amount TMIUP is an increase amount of the motor current value corresponding to the target braking force, specifically, an increase amount of the motor current value from the no-load current NOC. By causing the increase amount of the motor current value to be the target motor current value increase amount TMIUP, it is possible to suppress an excessive W / C pressure from being generated during parking braking. The target motor current value increase amount TMIUP is set to be equal to or greater than the motor current value increase amount necessary for generating the W / C pressure corresponding to the target braking force.

Here, the relationship between the target braking force or the corresponding W / C pressure and the target motor current value increase amount TMIUP is mapped, and the target motor current value increase amount TMIUP corresponding to the target braking force is calculated using the map. Have acquired. FIG. 6 is a map showing an example thereof, and is a map in which the target motor current value increase amount TMIUP increases in proportion to the magnitude of the target braking force. Note that the target braking force is a braking force necessary for maintaining the vehicle stopped, and is a value determined according to the slope of the slope. Therefore, the target braking current increases in proportion to the slope of the slope. There may be. Since the slope is expressed as a value of the G sensor 25, the target motor current value increase amount may be set based on the value of the G sensor 25.

Subsequently, the process proceeds to step 210, and it is determined whether or not the lock control time counter CLT exceeds a predetermined minimum lock control time MINLT. The lock control time counter CLT is a counter that measures an elapsed time since the lock control is started, and starts counting simultaneously with the start of the lock control process. The minimum lock control time MINLT is a minimum time that is assumed to be applied to the lock control, and is a value determined in advance according to the rotational speed of the motor 10 or the like. As in step 255 described later, when the motor current value reaches the target current value MI # TARGET, it is determined that the braking force generated by the EPB 2 has reached or approached a desired value. The motor current value may exceed the target current value MI # TARGET due to an inrush current at the initial stage. Therefore, by comparing the lock control time counter CLT with the minimum lock control time MINLT, the initial control period can be masked, and erroneous determination due to an inrush current or the like can be prevented.

Accordingly, if the lock control time counter CLT does not exceed the minimum time, the lock control is still continued. Therefore, the process proceeds to step 215, where the release state flag FREL is turned off and the lock control time counter CLT is set. The motor lock drive is turned on, that is, the motor 10 is rotated forward. Thereby, the brake pad 11 is moved to the brake disk 12 side with the forward rotation of the motor 10, and the locking operation by the EPB 2 is performed.

On the other hand, if an affirmative determination is made in step 210, the process proceeds to step 220, and a current value differential value ID obtained by differentiating the motor current value with respect to time is calculated. For example, the difference between the motor current values obtained during the current control cycle and the previous control cycle is defined as a current value differential value ID. Then, it is determined whether or not the current value differential value ID is larger than the current value differential threshold IDB.

The motor current value varies depending on the load applied to the motor 10. For example, in the case of the present embodiment, the load applied to the motor 10 corresponds to the pressing force pressing the brake pad 11 against the brake disc 12, and therefore has a value corresponding to the pressing force generated by the motor current value. For this reason, when the motor 10 is in a no-load state, the motor current value becomes a no-load current NOC, and when a load is applied to the motor 10, the motor current value starts to increase.

Therefore, by obtaining the current value differential value ID obtained by differentiating the motor current value with respect to time, a change in the motor current value can be detected, and by comparing the current value differential value ID with the current value differential threshold IDB, The start of increase in the motor current value can be detected. The current value differential threshold IDB is set to a value that is assumed that the motor current value starts to rise while excluding the noise-like fluctuation of the motor current value.

If an affirmative determination is made in step 220, the current value starting to increase indicating that the motor current value has started increasing is turned on in step 225, the flag FIUPS is turned on, and the process proceeds to step 230. If the determination in step 220 is negative, the motor 10 is not yet loaded, so the process of step 215 is executed again.

In step 230, after detecting the M / C pressure based on the detection signal of the M / C pressure sensor 26, whether the detected M / C pressure exceeds zero, that is, whether the M / C pressure is generated. Determine whether or not. If the M / C pressure is generated, it can be considered that the service brake 1 generates the W / C pressure according to the depression of the brake pedal 3 by the driver, and the service brake 1 generates the braking force. . If the brake force is generated by the service brake 1, the brake force generated by the EPB 2 may become larger than necessary unless the brake force is taken into consideration. Therefore, whether or not the service brake 1 is operating is determined based on whether or not the M / C pressure is generated. However, since the M / C pressure is not basically generated at the time of initial shipment, a negative determination is usually made. If an affirmative determination is made in step 230, the process proceeds to step 235 to execute a process considering the brake force generated by the service brake 1. If a negative determination is made, the process of step 235 is not performed and step 240 is performed. Proceed to

Specifically, in step 235, the target motor current value increase amount TMIUP is corrected as a process in consideration of the brake force generated by the service brake 1. That is, when the brake force is generated by the service brake 1, correction is performed to reduce the target motor current value increase amount TMIUP, and in this embodiment, the target motor current value increase amount according to the magnitude of the brake force. A subtraction value IDOWN of the target motor current value increase amount TMIUP that decreases TMIUP is obtained, and a value obtained by subtracting the subtraction value IDOWN from the target motor current value increase amount TMIUP obtained in step 205 is calculated.

In the present embodiment, the value of the subtraction value IDOWN corresponding to the M / C pressure is mapped, and the subtraction value IDOWN is obtained by extracting the value corresponding to the M / C pressure detected in step 230 based on the map. Seeking.

FIG. 7 shows an example of this, and is a map showing the relationship between the M / C pressure and the subtraction value IDOWN. As shown in this figure, the map is such that the subtraction value IDOWN increases in proportion to the magnitude of the M / C pressure, that is, the depression (depression force) of the brake pedal 3 by the driver. Therefore, in the case of the present embodiment, the subtraction value IDOWN corresponding to the M / C pressure detected in step 230 is read from the map shown in FIG. 7, and the subtraction value IDOWN is subtracted from the target motor current value increase amount TMIUP. The motor current value increase amount TMIUP is obtained.

However, it is not preferable that the target motor current value increase amount TMIUP is less than zero. Therefore, in step 235, the value obtained by subtracting the subtraction value IDOWN from the target motor current value increase amount TMIUP, or the value obtained by adding a predetermined value α (a positive constant) to the no-load current NOC, whichever is greater (MAX (TMIUP-IDOWN, NOC + α)) is the target motor current value increase TMIUP.

Thereafter, the process proceeds to step 240, and whether or not the case is not at the time of initial shipment, and if any of the three abnormalities of inrush current gain abnormality, no-load current gain abnormality, and rising current gain abnormality is present. Determine whether. Inrush current gain abnormality means gain abnormality during inrush current, no-load current gain abnormality means gain abnormality during no-load current, and rising current gain abnormality means gain abnormality during current rise. As described above, in the present embodiment, changes in the motor current value in the three regions at the time of inrush current at normal time, at no load current, and at the time of current rise are stored as reference values, which are stored when EPB2 is used. The abnormality is determined by comparing with the current value of the motor current value at. The presence or absence of abnormality is determined by comparison at this time. This determination is performed in various abnormality determination processes (see FIGS. 15 to 17), which will be described later, and it is determined whether there is an abnormality in this step based on the determination result.

Here, since negative determination is made at the time of initial shipment, the process proceeds to step 245, and a value obtained by adding the target motor current value increase amount TMIUP to the no-load current NOC is set to the target current value MI # TARGET. Further, when it is not at the time of initial shipment, if any one of the above three abnormalities is detected, the process proceeds to step 250. However, since the process does not proceed at the time of initial shipment, the explanation of step 250 is as follows. It will be described later.

Then, the process proceeds to step 255, and it is determined whether or not the motor current value exceeds the target current value MI # TARGET. When the motor current value exceeds the target current value MI # TARGET, a state in which a desired braking force is generated by the generated pressing force, that is, the friction surface of the brake pad 11 on the inner wall surface of the brake disk 12 to some extent by EPB2. It will be in a state of being pressed down with force. Therefore, the process of step 215 is repeated until an affirmative determination is made in this step, and if an affirmative determination is made, the process proceeds to step 260.

In step 260, the lock state flag FLOCK which means that the lock is completed is turned on, the lock control time counter CLT is set to 0, and the motor lock drive is turned off (stopped). Thereby, the rotation of the motor 10 is stopped and the braking force generated at that time is held. Thereby, the movement of the parked vehicle is regulated. Further, the current value starts to increase and the flag FIUPS is turned off. In this way, the lock control process is completed.

While the lock control process is being executed, the process proceeds to steps 115 to 125 in FIG. 4 and changes in the motor current value in three regions at the time of normal inrush current, no load current, and current rise. Is stored as a reference value.

Specifically, in step 115, an inrush current time norm setting process is performed in which a current descending slope norm is set as a norm as a criterion for determining whether the change in the motor current value at the time of the inrush current is normal or abnormal. A method of setting the current descending gradient standard will be described with reference to a comparison diagram of motor current values at the time of inrush current shown in FIG.

When the amplifier is faulty, an amplifier gain abnormality occurs. Therefore, as shown in FIG. 8, for example, the motor current value at the time of the inrush current is larger when the amplifier is faulty than when the amplifier is normal. For this reason, the descending slope of the motor current value when the inrush current is settled is larger in the abnormal time than in the normal time. Accordingly, for the inrush current, a current descending slope norm that is a norm of the descending slope of the motor current value is set, and abnormality detection is performed based on this current descending slope norm.

In the present embodiment, at the time of initial shipment, when the motor current value peaks at the inrush current, point A ′, abnormality detection timing B point, and time taken from point A ′ to B point T The current descending gradient is represented by (A′−B) / T. For example, when A ′ = 26 A, B = 6 A, and T = 24 ms, the current descending gradient is (26−6) /0.025=800.0 A / s. This is stored as a current descent gradient standard.

It should be noted that the time T from the point A ′ that is the peak of the inrush current that sets the current descent gradient standard to the point B that is the detection timing may be appropriately set based on the characteristics of the actuators that constitute the EPB 2.

FIG. 9 is a flowchart showing details of the current descent gradient norm setting process at the time of inrush current. When the current descending gradient norm setting process shown in step 115 is executed, each process shown in FIG. 9 is executed.

First, in step 300, it is determined whether or not the value of the lock control time counter CLT representing the lock control elapsed time is less than a predetermined time, for example, less than 100 ms, which is assumed as a time during which an inrush current can occur. If the lock control elapsed time is equal to or longer than the predetermined time, it is considered that the inrush current has already been generated. Therefore, the processing after step 305 is executed only when the lock control elapsed time is less than the predetermined time, and lock control is performed. If the elapsed time is equal to or longer than the predetermined time, the process is terminated as it is.

If an affirmative determination is made here, the process proceeds to step 305 to determine whether or not the storage of the current monitor A 'is complete. For example, this determination is performed based on whether or not a flag indicating that the storage of the current monitor A 'is completed is set. The current monitor A ′ is the motor current value at the point A ′ in FIG. 8, that is, the peak value of the motor current value at the time of inrush current. In this step, the peak value of the motor current value is stored. It is determined whether or not. Since the storage has not been completed at first, the process proceeds to step 310.

Then, in step 310, it is determined whether or not the state where the motor current value is decreasing continues. Here, the motor current value monitored in the current control cycle is defined as the current monitor I (n), and the current current monitor I (n) is less than the previous current monitor I (n−1), and the previous current monitor I (n When n-1) is less than the previous current monitor I (n-2), and the previous current monitor I (n-2) is less than the last current monitor I (n-3), it falls. Is determined to be continuous. The inrush current continuously increases up to the peak value and decreases continuously after reaching the peak value. For this reason, the peak value is when the motor current value starts to decrease. However, since the motor current value may decrease due to noise, in order to eliminate it, the peak value is adopted when the motor current value decreases continuously.

Therefore, if a negative determination is made in step 310, the process proceeds to step 315, where the peak of the current monitor I (n) at the time of the inrush current (hereinafter referred to as the inrush current monitor peak) is compared with the inrush current monitor peak up to the previous control cycle and this time. Is updated to the larger one of the current monitors I (n) of the control cycle. Then, the process of step 315 is continuously executed until an affirmative determination is made in step 310, and if an affirmative determination is made, the process proceeds to step 320, and the current monitor A ′ at that time is set to the current monitor A ′ and then the current monitor A ′ A flag indicating that the storage is completed is set, and the process ends.

Thereafter, since an affirmative determination is made at step 305, the routine proceeds to step 325, where the inrush current determination time T, that is, the time T taken from point A 'to point B shown in FIG. 8, is counted. In step 330, it is determined whether or not the current monitor I (n) has reached the current monitor B, that is, the motor current value at point B in FIG. 8 described above, and the current monitor I (n) is the current monitor. Step 325 is incremented until it reaches less than B. Thereafter, when the current monitor I (n) reaches less than the current monitor B, the routine proceeds to step 335, where the current descending gradient standard is set. Specifically, a value obtained by dividing the difference between the current monitor A ′ and the current monitor B by the inrush current determination time T ((current monitor A′−current monitor B) / inrush current determination time T) is a current descent gradient standard. Set as. In this way, the inrush current time norm setting process in step 115 of FIG. 4 is completed.

Next, in step 120 of FIG. 4, a no-load current time norm setting process for setting a no-load current value norm as a norm as a criterion for determining whether the motor current value at the no-load current is normal or abnormal is performed. Do. A method for setting the no-load current reference will be described with reference to a comparison diagram of motor current values at no-load current shown in FIG.

Since an amplifier gain abnormality occurs when the amplifier fails, the motor current value at the time of no-load current is larger when the amplifier is faulty, as shown in FIG. 10, for example, than when the amplifier is normal. Therefore, regarding no-load current, a no-load current value norm that is a norm of the magnitude of the motor current value at the time of no-load current is set, and abnormality detection is performed based on this no-load current value norm.

In the case of this embodiment, at the time of initial shipment, the minimum value of the motor current value is measured from the end time of the inrush current, and after reaching the predetermined no-load current value reference after the end of the no-load current. As the no-load current time T, the no-load current value standard is set. Specifically, a current minimum normative value C that is the minimum value of the motor current value during the no-load current time T is obtained and stored as a no-load current value norm.

Note that the no-load current time T may be set as appropriate based on the characteristics of the actuators constituting the EPB 2.

FIG. 11 is a flowchart showing details of the no-load current value norm setting process at the time of no-load current. When the no-load current value norm setting process shown in step 120 is executed, each process shown in FIG. 11 is executed.

First, in step 400, the value of the lock control time counter CLT representing the lock control elapsed time exceeds a predetermined time, for example, 100 ms, which is assumed as the time when the inrush current can be completed, and the current monitor I (n) is It is determined whether it is less than the no-load current value standard. The no-load current value reference is a reference value assumed as the no-load current value, and when it is less than the no-load current value reference, it means that the no-load current value is approaching. This no-load current value reference is set to a somewhat large value (for example, 3A) so as to cope with the case where the no-load current value becomes large. If the determination in step 400 is negative, it is not the timing for setting the no-load current value norm, so the processing is terminated as it is, and if an affirmative determination is made, the process proceeds to step 405.

In step 405, the current minimum normative value C (n) of the current control cycle is calculated. Specifically, the current minimum normative value C (n-1) of the previous control cycle is compared with the current monitor I (n) of the current control cycle, and the lower one is the current minimum norm of the current control cycle. Let it be the value C (n). The initial value of the minimum current reference value C (n) is set to the no-load current value reference, and when the current monitor I (n) falls below the no-load current value reference, the minimum current reference value C (n) is updated. To go. For this reason, the minimum value of the motor current value, that is, the no-load current value is set to the minimum current reference value C (n). When the current monitor I (n) again exceeds the no-load current value reference, the calculation of the current minimum value reference C (n) is completed, and the current minimum value reference C (n) at that time is the final current. The minimum normative value C is set, and this minimum current normative value C is stored as a no-load current value norm.

Subsequently, in step 125 of FIG. 4, a current ascending gradient norm setting process for setting a current ascending gradient norm as a norm serving as a criterion for determining whether the change in the motor current value at the time of current increase is normal or abnormal is performed. . A method for setting the current rise gradient standard will be described with reference to a comparison diagram of motor current values at the time of current rise shown in FIG.

When the amplifier is faulty, an amplifier gain abnormality occurs. Therefore, as shown in FIG. 12, for example, the motor current value at the time of current rise is larger when the amplifier is faulty than when the amplifier is normal. For this reason, the rising gradient at the time of current rise in which the brake pad 11 comes into contact with the brake disc 12 and a load is applied to the motor 10 to increase the motor current value is larger in the abnormal time than in the normal time. Accordingly, when the current rises, a current rise gradient norm that is a norm of the motor current value rise gradient is set, and abnormality detection is performed based on this current rise gradient norm.

In the case of this embodiment, at the time of initial shipment, when the motor current value becomes the first current monitor value when the current rises, the point E ′ and the abnormality detection timing become the second current monitor value larger than the first current monitor value. Assuming that the time taken from the F ′ point and the E ′ point to the F ′ point is T ′, the current rising gradient is represented by (F′−E ′) / T ′. For example, when E ′ = 6 A, F ′ = 16 A, and T ′ = 500 ms, the current increase gradient is (16−6) /0.5=20.0 A / s. This is memorized as a current rising gradient standard.

In addition, about each point (E ', F') used as the 1st current monitor value and 2nd current monitor value which sets an electric current climb gradient norm, and the time T 'between them, the characteristic of each actuator which comprises EPB2 It may be set as appropriate based on the above.

FIG. 13 is a flowchart showing details of the current increase gradient norm setting process at the time of current increase. When the current increase gradient norm setting process shown in step 125 is executed, each process shown in FIG. 13 is executed.

First, in step 500, the value of the lock control time counter CLT representing the lock control elapsed time exceeds a predetermined time, for example, 100 ms, which is assumed as a time during which an inrush current can occur, and the current monitor I (n) is It is determined whether or not the no-load current value standard is exceeded. Thereby, after the inrush current has been generated, it can be determined that the motor current value has increased from the no-load current. Only when an affirmative determination is made here, the processing from step 505 is executed, and when a negative determination is made, the processing ends.

In step 505, the monitor value of the motor current at the current control cycle is changed from the current monitor I (n-1), which is the monitor value of the motor current value at the previous control cycle, to a value less than the first current monitor value. It is determined whether or not a certain current monitor I (n) has changed to a state where it exceeds the first current monitor value. That is, it is determined whether or not the motor current value has reached the point E 'shown in FIG. If an affirmative determination is made here, the routine proceeds to step 510, where it is instructed to turn on the rising time elapsed counter that measures the time after the motor current value reaches the point E ', and then the routine proceeds to step 515. If a negative determination is made here, the motor current value has not yet reached point E ', or it has already reached point E' and the rising time elapsed counter is being turned on. Proceed to step 515.

In step 515, the current monitor I (n) at the current control cycle exceeds the second current monitor value from the state in which the current monitor I (n-1) at the previous control cycle is less than the second current monitor value. It is determined whether or not the state has changed. That is, it is determined whether or not the motor current value has reached the point F ′ shown in FIG. If an affirmative determination is made here, the process proceeds to step 520, instructed to turn off the rising time elapsed counter, and then proceeds to step 525. If the determination in step 515 is negative, the motor current value has not yet reached the F ′ point, or has already reached the F ′ point and the rising time elapsed counter is turned off. Proceed to step 525.

In step 525, it is determined whether or not the rising time elapsed counter is instructed to be turned on. If an affirmative determination is made here, the rising time elapsed counter is counted up and then the process proceeds to step 535. If a negative determination is made, the process proceeds to step 535 as it is. In this way, the count of the rising time elapsed counter is stopped when the rising time elapsed counter is switched on from the state instructed to turn off, so the count value at this time is The motor current value is a time T ′ taken from the point E ′ to the point F ′.

In step 535, the rising time elapsed counter is on during the previous control cycle and the rising time elapsed counter is switched off during the current control cycle, that is, the motor current value at the abnormal timing is F ′. It is determined whether or not it is time to reach a point. When an affirmative determination is made in step 535, the process proceeds to step 540, where the second current monitor value is calculated using the count value of the rising time elapsed counter, that is, the time T ′ from the point E ′ to the point F ′. A value obtained by dividing the difference from the first current monitor value by the count value of the rising time elapsed counter is set as the current rising gradient standard. In this way, the current increase gradient norm setting process in step 125 of FIG. 4 is completed.

Thereafter, the process proceeds to step 130 in FIG. 4 to perform lock / release display processing. FIG. 14 is a flowchart showing details of the lock / release display process. The lock / release display process will be described with reference to FIG.

In step 600, it is determined whether or not the lock state flag FLOCK is turned on. If a negative determination is made here, the process proceeds to step 605 to turn off the lock / release display lamp 24, and if an affirmative determination is made, the process proceeds to step 610 to turn on the lock / release display lamp 24. In this way, the lock / release display lamp 24 is turned on in the locked state, and the lock / release display lamp 24 is turned off when the release state or release control is started. As a result, it is possible to make the driver recognize whether or not it is in the locked state. Then, if the lock operation has been completed in the lock control shown in step 110 of FIG. 4, the lock / release display lamp 24 is turned on in this process, and the locked state is displayed. In this way, the lock / release display process is completed.

Thus, setting of various norms by completing the lock control performed in the parking brake control process at the time of initial shipment is completed. When the setting of various norms is completed, the flag indicating the initial shipment time is reset so that it can be confirmed that it is not the initial shipment time in the subsequent processing. In the initial shipment, it is assumed that a lock request is issued first, but a release request may be issued before the lock request. Therefore, even if a negative determination is made in step 105, if it is determined in step 135 that there is a release request, for example, the operation SW23 is turned off and the driver is operating the EPB 2 to enter the release state. If it is determined, the process proceeds to step 140 to perform release control. When there is no release request in addition to the lock request, the parking brake control process is terminated as it is. Details of the release control will be described later.

Subsequently, when the vehicle is shipped and actually used, a negative determination is made in step 100 of FIG. In step 145, it is determined whether or not there is a lock request in the same manner as in step 105 described above. If an affirmative determination is made, the process proceeds to step 150 and lock control is executed. Specifically, the lock control is executed by the lock control process shown in FIG. When such lock control is executed, basically the same operation as at the time of initial shipment is performed. However, since the determination in step 240 is not at the time of initial shipment, if there is an abnormality among any of the three abnormalities of inrush current gain abnormality, no-load current gain abnormality, and rising current gain abnormality, step 250 is performed. Will go on. The determination of the presence / absence of various abnormalities is performed in various abnormality determination processes (see FIGS. 15 to 17) described later. Based on the determination results, it is determined whether there is an abnormality in this step. Yes.

If there is an abnormality, the process proceeds to step 250, where the target current is obtained by multiplying the value obtained by adding the target motor current value increase amount TMIUP to the no-load current NOC and the current gain abnormality correction coefficient. Set to the value MI # TARGET. The current gain abnormality correction coefficient is the target current value MI # TARGET that is normally calculated as the value obtained by adding the target motor current value increase TMIUP to the no-load current NOC when an amplifier abnormality occurs. This is a coefficient for making a larger value. This coefficient is set to a value larger than 1, and may be a constant value used when any one of the three areas is determined to be abnormal. Depending on where in the three areas it is determined to be abnormal May have different values.

As a result, the target current value MI # TARGET is set to a value larger than the value set in the normal state, and the lock operation time required until the motor current value reaches the target current value MI # TARGET in step 255 is corrected. it can. Therefore, even when there is an abnormality, it is possible to appropriately perform the lock control, and it is possible to avoid stopping the EPB 2.

When the lock control in step 150 of FIG. 4 is executed in this way, the process proceeds to step 155, where current descent gradient abnormality determination processing at the time of inrush current is performed. An outline of the current descending gradient abnormality determination process will be described with reference to FIG.

In the current descending gradient abnormality determination process, it is determined whether or not an inrush current gain abnormality has occurred by comparing the current descending gradient at the current inrush current with the current descending gradient standard.

First, the current descending gradient at the time of inrush current in the current lock control is calculated by the same method as the current descending gradient norm setting method described above. Specifically, as shown in FIG. 8, when the motor current value reaches a peak at the time of the inrush current, point A, abnormality detection timing B point, and time taken from point A to point B, T The current descending gradient is obtained by calculating (AB) / T. For example, if A = 46 A, B = 6 A, and T = 40 ms, the current descending gradient is (46−6) /0.04=1000.0 A / s.

Since this is the current descending slope at the current inrush current, it is determined whether or not an inrush current gain abnormality has occurred by comparing with the current descending slope norm (A'-B) / T that has already been set. It becomes possible to do.

FIG. 15 is a flowchart showing details of the current descent gradient abnormality determination process at the time of inrush current. When the current descending gradient abnormality determination process shown in step 155 is executed, each process shown in FIG. 15 is executed.

First, in steps 700 to 735, processing similar to that in steps 300 to 335 in FIG. 9 is performed, and (AB) / T is calculated to calculate the current descending gradient at the current inrush current. Then, the process proceeds to step 740, where it is determined whether or not the ratio of the current descent gradient at the current inrush current to the current descent gradient standard is larger than a predetermined abnormality detection value for inrush current gradient comparison. That is, it is determined whether or not the current descending gradient at the current inrush current is larger than a predetermined ratio as compared with the current descending gradient norm.

If a negative determination is made here, since no inrush current gain abnormality has occurred, the routine proceeds to step 745, where there is no inrush current gain abnormality, for example, a flag indicating that an inrush current gain abnormality has occurred is reset and the processing is terminated. If an affirmative determination is made, an inrush current gain abnormality has occurred, so the routine proceeds to step 750, where there is an inrush current gain abnormality, for example, a flag indicating that an inrush current gain abnormality has occurred is set, and the process is terminated. In this way, it can be determined whether or not an inrush current gain abnormality has occurred.

Next, in step 160 of FIG. 4, a no-load current value abnormality determination process is performed, which is a determination of whether the motor current value at the time of no-load current is normal or abnormal. An outline of the no-load current abnormality determination process will be described with reference to FIG.

In the no-load current value abnormality determination process, it is determined whether or not a no-load current gain abnormality has occurred by comparing the no-load current value at the current no-load current with the no-load current value standard.

First, the no-load current value at the no-load current in the current lock control is calculated by the same method as the above-described no-load current value norm setting method. Specifically, as shown in FIG. 10, the minimum value (hereinafter referred to as the current minimum value) D of the motor current value is measured from the end time of the inrush current, and after the no-load current ends, a predetermined no-load current value reference The minimum current value D during the no-load current time T until reaching the time α is obtained.

Since this current minimum value D becomes the current no-load current value, whether or not an abnormal no-load current gain has occurred is compared with the current minimum normative value C which is an already set no-load current value norm. It becomes possible to determine.

FIG. 16 is a flowchart showing details of the no-load current value abnormality determination process at the time of no-load current. When the no-load current value abnormality determination process shown in step 160 is executed, each process shown in FIG. 16 is executed.

First, in step 800, the same determination as in step 400 of FIG. 11 is performed. When an affirmative determination is made, the process proceeds to step 805 to calculate the current minimum value D (n) in the current control cycle. Specifically, the current minimum value D (n-1) of the previous control cycle is compared with the current monitor I (n) of the current control cycle, and the lower one is the current minimum value D of the current control cycle. (N). The initial value of the minimum current value D (n) is set to the no-load current value reference. When the current monitor I (n) falls below the no-load current value reference, the minimum current value D (n) is updated. . Therefore, the current minimum value D (n) is finally the minimum value of the motor current value, and the current minimum value D (n) at that time is the final current minimum value D, which is set as the no-load current value. Will be.

On the other hand, when a negative determination is made at step 800, the process proceeds to step 810. Then, the value of the lock control time counter CLT indicating the lock control elapsed time exceeds a predetermined time, for example, 100 ms, which is assumed as the time at which the inrush current can be completed, and the current monitor I (n− From the state in which 1) is less than the no-load current value reference, it is determined whether or not it is the timing when the current monitor I (n) of the current control cycle becomes greater than or equal to the no-load current value reference. That is, it is determined whether or not the no-load current has been completed. If an affirmative determination is made here, the process proceeds to a no-load current gain abnormality determination process shown in step 815 and thereafter, and if a negative determination is made, the process ends.

In step 815, the no-load current value reference C stored as the no-load current value reference is used, and the no-load current value upper limit CHiLimit and the no-load Calculate the current value lower limit CLowLimit. Specifically, the no-load current value upper limit CHiLimit and the no-load current value lower limit CLowLimit are calculated by multiplying the current minimum normative value C by a constant (1 ± variation coefficient) with a predetermined variation coefficient. . For example, if the current minimum normative value C is 1.1 A and the variation coefficient is 0.5, the no-load current value upper limit CHiLimit is 1.65 A (= 1.1 × (1 + 0.5)), the no-load current value The lower limit CLowLimit is 0.55 A (= 1.1 × (1-0.5)). In this embodiment, the current minimum normative value C is stored as a no-load current value norm, but these no-load current value upper limit CHiLimit and no-load current value lower limit CLowLimit are stored as no-load current value norms from the beginning. You can keep it.

Then, the process proceeds to step 820, where the current minimum value D, that is, the current minimum value D (n) finally updated in step 805 is included in the range from the no-load current value upper limit CHiLimit to the no-load current value lower limit CLowLimit. It is determined whether or not.

If a negative determination is made here, no no-load current gain abnormality has occurred, and therefore, the process proceeds to step 825, where no load current gain abnormality has occurred, for example, a flag indicating that no load current gain abnormality has occurred is reset and processing is performed. finish. If an affirmative determination is made, a no-load current gain abnormality has occurred. Therefore, the process proceeds to step 830, where there is a no-load current gain abnormality. For example, a flag indicating that a no-load current gain abnormality has occurred is set. finish. In this way, it can be determined whether or not a no-load current gain abnormality has occurred.

Next, in step 165 of FIG. 4, a current increase gradient abnormality determination process is performed, which is a determination of whether the motor current value at the time of current increase is normal or abnormal. The outline of this current rising gradient abnormality determination process will be described with reference to FIG.

In the current rising gradient abnormality determination process, it is determined whether or not the rising current gain abnormality has occurred by comparing the current rising gradient at the current current rising time with the current rising gradient norm.

First, the current increase gradient at the time of current increase in the current lock control is calculated by the same method as the current increase gradient norm setting method described above. More specifically, as shown in FIG. 12, when the motor current value becomes the first current monitor value when the current rises, point E, abnormality detection timing becomes the second current monitor value F point, E point to F point Assuming that the time taken to reach T is T, the current rise gradient is calculated from (FE) / T. For example, if E = 6 A, F = 16 A, and T = 200 ms, the current rise gradient is (16−6) /0.2=50.0 A / s.

Since this is the current rise gradient at the current rise, the current rise gradient norm (F'-E ') / T is compared to determine whether or not a rise current gain abnormality has occurred. It becomes possible to judge.

FIG. 17 is a flowchart showing details of the current increase gradient abnormality determination process at the time of current increase. When the current increase gradient abnormality determination process shown in step 165 is executed, each process shown in FIG. 17 is executed.

First, in steps 800 to 840, processing similar to that in steps 500 to 540 in FIG. 13 is performed, and (FE) / T is calculated to calculate the current increase gradient at the current current increase. Then, the process proceeds to step 845, where it is determined whether or not the ratio of the current rise gradient at the current rise to the current rise gradient norm is larger than a predetermined abnormality detection value for the current rise slope comparison. That is, it is determined whether or not the current increase gradient at the current current increase is greater than a predetermined ratio as compared with the current increase gradient norm.

If a negative determination is made here, since no rising current gain abnormality has occurred, the routine proceeds to step 850, where there is no rising current gain abnormality, for example, a flag indicating that a rising current gain abnormality has occurred is reset and the processing is terminated. If an affirmative determination is made, a rise current gain abnormality has occurred, so that the routine proceeds to step 855 where a rise current gain abnormality has occurred, for example, a flag indicating that a rise current gain abnormality has occurred is set, and the process is terminated. In this way, it can be determined whether or not a rising current gain abnormality has occurred.

In this way, when various abnormality determination processes are executed, the determination results are used in the determination of step 240 in FIG. Then, if any of the three abnormalities of inrush current gain abnormality, no-load current gain abnormality, and rising current gain abnormality is present, the target current value MI # TARGET is corrected accordingly. As a result, the lock operation time required for the motor current value to reach the target current value MI # TARGET is corrected so that the lock control can be appropriately performed even in an abnormal state. You can avoid having to stop.

When the various abnormality determination processes are completed, the lock / release display process is executed in step 130 of FIG. This process is the same as above, but if the motor current value reaches the target current value MI # TARGET in the lock control and the lock operation is finished, the lock / release display lamp 24 is turned on and the lock state is established. Will be displayed. In this way, the lock / release display process is completed.

Furthermore, when there is a release request after the vehicle is shipped, a negative determination is made at step 145 and the routine proceeds to step 170. In step 170, it is determined whether there is a release request, for example, whether the operation SW 23 is turned off. The state in which the operation SW 23 is off means that the driver is operating the EPB 2 to enter the release state. If there is a release request, an affirmative determination is made at step 170, and the routine proceeds to step 175 where release control is performed. Details of the release control will be described with reference to a flowchart of release control processing shown in FIG. Note that the same operation as the release control process in step 175 is performed in the release control process in step 140 of FIG.

In the release control process, the EPB 2 is operated by rotating the motor 10, and the brake force generated by the EPB-ECU 9 is released.

First, in step 900, the absolute value | I (n-1) -I (n) | of the difference between the current monitor I (n-1) in the previous control cycle and the current monitor I (n) in the current control cycle is It is determined whether or not the release control end determination current value is less than RENDI.

As described above, the motor current value fluctuates in accordance with the load applied to the motor 10, and when the pressing force pressing the brake pad 11 against the brake disk 12 disappears, the motor current value is constant at the no-load current NOC. And there will be no fluctuations. For this reason, the release control end determination current value RENDI is set to a current change amount that is assumed to cause no load on the motor 10, and the absolute value | I (n-1) -I (n) | When the current value is less than RENDI, it is determined that the brake pad 11 has moved away from the brake disk 12 and the load on the motor 10 has been removed.

Therefore, if a negative determination is made in step 900, the routine proceeds to step 905, where the lock state flag FLOCK is turned off and the motor release drive is turned on, that is, the motor 10 is rotated in the reverse direction. As a result, the brake pad 11 is moved away from the brake disc 12 with the reverse rotation of the motor 10.

If the determination in step 900 is affirmative, the process proceeds to step 910 to increment the release control end counter CREND, and then proceeds to step 915 to determine whether or not the release control end counter CREND has exceeded the release control end time TREND. .

The release control end time TREND is the time when the release control is continued from the timing when the load on the motor 10 is lost, the timing when the brake pad 11 is separated from the brake disk 12, and the brake pad 11 is moved by the motor 10 during the lock control. The longer the amount, the longer.

Here, if the release control end counter CREND does not exceed the release control end time TREND, the release control is still continued, so the processing of step 905 is executed. When the release control end counter CREND exceeds the release control end time TREND, the process proceeds to step 920, where the release state flag FREL, which means that the release is completed, is turned on and the release control end counter CREND is set to 0 to drive the motor release. Turn off. Accordingly, the rotation of the motor 10 is stopped, and the brake pad 11 is held in a state of being separated from the brake disk 12. In this way, the release control process is completed. Thereafter, the process proceeds to the lock / release control process of step 130 and the above-described process is performed. When the release control is started, since the lock state flag FLOCK is turned off, the lock / release display lamp 24 is turned off, indicating that the lock state is not set. Thereby, the parking brake control process after the initial shipment ends.

As described above, in the present embodiment, the change in the motor current value in the three regions at the time of inrush current at normal time, at the time of no load current, and at the time of current rise is stored as a reference value, and this is used as the reference value of EPB2. The abnormality is detected by comparing with the current value of the motor current value at the time. When an abnormality is detected, for example, the lock operation time is corrected to be longer by setting the target current value to be larger than the value set at the normal time. As a result, even when there is an abnormality, it is possible to appropriately perform the lock control, and it is possible to avoid stopping the EPB 2. Therefore, it is possible to detect not only failures such as cable disconnection and short circuit, mechanical damage of EPB2, but also abnormalities that appear only with relatively small current value changes such as amplifier gain abnormalities, and take measures against them. Is possible.

In this embodiment, the amplifier gain abnormality is exemplified as an abnormality that appears only with a relatively small current value change. However, other abnormalities that cause a small current value change can be detected in the same manner. it can. Therefore, it is possible to identify performance and functional problems that cause such a small change in current value, and to take measures against them.

(Second Embodiment)
A second embodiment of the present invention will be described. Compared to the first embodiment, the present embodiment is configured to determine the wear of the brake pad 11 that is a friction material (hereinafter referred to as pad wear) in the parking brake control process. Since it is the same as the embodiment, only the parts different from the first embodiment will be described.

FIG. 19 is an overall flowchart of parking brake control processing related to the release operation of this embodiment. As shown in this figure, the parking brake control process of this embodiment is substantially the same as the parking brake control process shown in FIG. 4 described in the first embodiment, but the current increase gradient abnormality determination process of step 165 is performed. After performing, it progresses to step 180 and performs pad wear determination processing.

In the parking brake control process, abnormality determination processing is performed at the time of inrush current, no load current, and current rise, but the abnormality detection value, variation coefficient and current for inrush current gradient comparison used for each abnormality determination process The abnormality detection value for comparing the rising gradient is determined in consideration of pad wear and the like. FIG. 20 is a diagram showing the relationship between the actual current value to be output as the motor current value and the monitor value. As shown in this figure, the monitor value varies with respect to the actual current value. Variation factors mainly include variations due to current monitor variation, pad wear, and aging, and each abnormality detection value and variation coefficient are set as described above, taking into account variations due to these variation factors. .

For example, FIG. 20 shows an example in which a normal range and an abnormal range are set with a current monitor variation of 7% and a pad wear variation of 30%. In the initial shipment when there is no variation such as pad wear, the variation range due to current monitor variation is considered to be the normal range, but as the pad wear variation is included with use, the normal range including the variation range is included. Is set, and the outside of the range is set as the abnormal range. Each abnormality detection value and variation coefficient are set so as to be in this abnormality range. Note that the influence of the variation due to pad wear basically occurs when the brake pad 11 comes into contact with the brake disc 12, and is therefore only relevant when the current rises, and is hardly relevant at the time of inrush current or no-load current. For this reason, the normal range and abnormal range are set only when the current rises, taking into account variations due to pad wear, and the normal range and abnormal range are set without taking into account variations due to pad wear during inrush current or no-load current. It may be.

In this way, each abnormality detection value and variation coefficient are set in consideration of various variation factors. And, if the abnormality detection value for the current rise gradient comparison is set without taking into account variations due to pad wear, it will be judged as abnormal even during pad wear, so the variations due to pad wear will be taken into account. And set it.

However, if each abnormality detection value and variation coefficient are set with and without the variation due to pad wear, it is possible to detect the pad wear using them. For example, even if the abnormality detection value and variation coefficient for slope comparison at inrush current are set without considering the variation due to pad wear, the effect of variation due to pad wear at inrush current or no load current Therefore, it is determined that there is no gain abnormality even if pad wear occurs. Even if pad wear has occurred, it is determined that there is no gain abnormality if the abnormality detection value for current rise gradient comparison is set in consideration of variations due to pad wear. Then, when pad wear has occurred, if the abnormality detection value for gradient comparison during current rise is set without taking into account variations due to pad wear, it is determined that there is a gain abnormality. Based on this, pad wear is detected.

FIG. 21 is a flowchart showing details of the pad wear determination process. The pad wear determination process will be described with reference to this figure.

First, in step 1000, it is determined whether or not all of inrush current gain abnormality, no load current gain abnormality, and no rising current gain abnormality are satisfied. Each gain abnormality at this time is performed using an abnormality detection value for detecting pad wear and a variation coefficient. For example, the abnormality detection value and variation coefficient for inrush current gradient comparison are set without taking into account variations due to pad wear, and the error detection value for current rise gradient comparison is set taking into account variations due to pad wear. It is. However, the abnormality detection value and the variation coefficient for inrush current gradient comparison may be set in consideration of variations due to pad wear.

If a negative determination is made here, it means that a gain abnormality greater than the pad wear variation has occurred, and therefore, the process proceeds to step 1005 to indicate no pad wear. For example, resetting a flag indicating the presence of pad wear indicates no pad wear. If an affirmative determination is made, the process proceeds to step 1010.

In Step 1010, it is determined whether or not the ratio of the current rise gradient at the current rise to the current rise gradient norm is larger than a predetermined abnormality detection value for current rise slope comparison. At this time, an abnormal detection value for detecting pad wear, that is, a value set without taking into account variations due to pad wear is used as an abnormal detection value for comparing the current rise gradient. Therefore, if the determination is affirmative here, it means that pad wear has occurred, and the routine proceeds to step 1015 to indicate that pad wear has occurred. For example, a flag indicating the presence of pad wear is set. If a negative determination is made, the process proceeds to step 1005 to indicate no pad wear. In this way, the pad wear determination process ends. If the pad wear is determined to be due to the pad wear determination, the EPB-ECU 9 outputs a signal to that effect to the notification device 27, and the notification device 27 displays that the pad wear has occurred. Thereby, it is possible to prompt the driver to replace the brake pad 11.

As described above, the pad wear determination can be performed in the parking brake control process. Thereby, the presence or absence of pad wear can be detected, the driver can be notified that pad wear has occurred, and the driver can take measures such as pad replacement. Further, based on the detection result of the presence or absence of pad wear, the abnormality detection value for inrush current gradient comparison, the variation coefficient, and the abnormality detection value for current rising gradient comparison can be corrected. That is, each abnormality detection value and variation coefficient can be set as a value that does not take into account pad wear when there is no pad wear, and a value that takes into account pad wear when there is pad wear.

(Third embodiment)
A third embodiment of the present invention will be described. The present embodiment is different from the first and second embodiments in the abnormality detection method at the time of current rise, and the other aspects are the same as those in the first and second embodiments. Only portions different from the embodiment will be described.

Specifically, in the first and second embodiments described above, there is one abnormality detection timing at the time of current rise, but in this embodiment, there are a plurality of abnormality detection timings. For example, in the first and second embodiments, the abnormality detection timing is set when the motor current value becomes the second current monitor value, but in this embodiment, the abnormality detection is also performed when the motor current value becomes the third current monitor value. Timing is set, and at least two or more abnormality detection timings are set.

FIG. 22 is a comparison diagram of motor current values at the time of current increase when normal and when gain is abnormal due to an amplifier failure or the like. First, at the time of initial shipment, when the motor current value becomes the first current monitor value when the current rises, the point E ′, the abnormality detection timing becomes the point F ′ that becomes the second current monitor value, and a third current monitor smaller than that. The time taken from the G ′ point and the E ′ point to the F ′ point as values is T1, and the time taken from the E ′ point to the G ′ point is T2 ′. Then, the current rising gradient is expressed by two of (F'-E ') / T1' and (G'-E ') / T2'. These are stored as the first and second current rising gradient norms.

Similarly, in the current rise gradient abnormality determination process, the point E is when the motor current value becomes the first current monitor value when the current rises, and the point F when the abnormality detection timing becomes the second current monitor value. The time taken from the G point and the E point to the F point as the third third current monitor value is T1, and the time taken from the E point to the G point is T2. Then, two of (FE) / T1 and (GE) / T2 are calculated as current rising gradients. These are the first and second current rise gradients that are current rise gradients in the periods T1 and T2 corresponding to the first and second current rise gradient standards, respectively.

Therefore, it is possible to determine whether or not there is an abnormality in the rising current gain by comparing the first and second current rising gradients with the first and second current rising gradient standards, respectively. As described above, when the abnormality detection at the time of current rise is performed with two or more abnormality detection timings, the following effects can be obtained. Although the rising gradient at the time of current increase changes according to the characteristics of EPB2, the change in motor current value is not always linear, so the gradient changes depending on the setting of the abnormality detection timing. Therefore, by having two or more abnormality detection timings, it is possible to reduce the influence of the change in gradient according to the characteristics of EPB2, and it is possible to perform abnormality detection regardless of the characteristics of EPB2. It becomes.

(Fourth embodiment)
A fourth embodiment of the present invention will be described. In the present embodiment, the parking brake control process is performed in consideration of the voltage fluctuation of the drive power source of the EPB 2 with respect to the first to third embodiments, and the others are the same as the first to third embodiments. Since this is the same, only the differences from the first to third embodiments will be described.

The change in the motor current value when the EPB 2 is locked is as described above. After the rush current occurs, the motor current value decreases to the no-load current value, becomes constant at the no-load current value, and then increases. . As shown in FIG. 3, when a gain abnormality occurs due to an amplifier failure or the like, the motor current value becomes larger than that in the normal state. However, when the voltage fluctuation of the drive power source of EPB2 occurs, the motor current value changes even if it is normal. For this reason, it is preferable to correct the value compared with each standard value according to the voltage fluctuation of the drive power supply.

FIG. 23 is a diagram showing changes in the motor current value when voltage fluctuation (voltage increase) of the drive power source occurs. For example, assuming that the voltage of the drive power supply is 12V when it is normal and 14V when the voltage fluctuates, the current increase gradient becomes larger when the voltage fluctuates than when it is normal. Therefore, for example, if the current rise gradient is calculated during voltage fluctuations, the current rise gradient is calculated as a large value even if it is normal. It can be. For this reason, the current increase gradient calculated when the voltage fluctuates is corrected to the current increase gradient reference when normal is set.

Specifically, the drive power supply voltage when the current rise gradient is calculated is the abnormality detection timing voltage, and the drive power supply voltage when various reference values are set is the reference voltage. The corrected current rise gradient is calculated by multiplying the voltage divided by the abnormality detection timing voltage. For example, when the current increase gradient is 50 A, the abnormality detection timing voltage is 14 V, and the reference voltage is 12 V, the corrected current increase gradient is 42.8 (= 50 × 14/12).

In this way, the corrected current increase gradient is calculated, and the current increase gradient at the current increase in the current increase gradient abnormality determination process is compared with the current increase gradient standard (see step 845 in FIG. 17). The corrected current increase gradient is used as the current increase gradient at the current increase. As a result, it is possible to accurately compare the current rise gradient and the current rise gradient norm without being affected by fluctuations in the power supply voltage, and more accurately determine the gain abnormality when the current rises.

Here, the current rising gradient at the time of current rising has been described as an example, but the current falling gradient at the time of inrush current and the no-load current value at the time of no-load current are similarly determined according to the voltage fluctuation of the drive power supply. It can be corrected.

(Fifth embodiment)
A fifth embodiment of the present invention will be described. In the present embodiment, a reference value is set in an abnormal state with respect to the first to fourth embodiments, and the other aspects are the same as those of the first to fourth embodiments. Only portions different from the embodiment will be described.

In each of the above embodiments, the standard value is set at the time of initial shipment, that is, normal, but the current rising gradient standard may vary depending on the material of the brake pad 11. Therefore, in the present embodiment, an abnormal state in which the brake pad 11 is worn out and is no longer in the normal use region, that is, a state after wear at which the influence of the material of the brake pad 11 is eliminated is used as the reference value.

FIG. 24 is a comparison diagram of motor current values at the time of current increase after the brake pad 11 is worn (when abnormal) and before wear (when normal).

When the amplifier fails, an amplifier gain abnormality occurs. Therefore, for example, as shown in FIG. 24, the motor current value at the time of current rise is larger in the amplifier failure than in the normal state. For this reason, the rising gradient at the time of current rise in which the brake pad 11 comes into contact with the brake disc 12 and a load is applied to the motor 10 to increase the motor current value is larger in the abnormal time than in the normal time. Accordingly, when the current rises, a current rise gradient norm that is a norm of the motor current value rise gradient is set at the time of abnormality, and abnormality detection is performed based on this current rise gradient norm.

In the case of the present embodiment, when the brake pad 11 is worn, when the motor current value becomes the first current monitor value when the current rises, the point E ′, and the abnormality detection timing is the second current larger than the first current monitor value. Assuming that the time taken from the F ′ point and the E ′ point to the F ′ point as the monitor value is T ′, the time T ′ is a value corresponding to the current rising gradient. For this reason, this time T ′ is stored as a current rising gradient standard or set as a constant at the time of design.

In addition, about each point (E ', F') used as the 1st current monitor value and 2nd current monitor value which sets an electric current climb gradient norm, and the time T 'between them, the characteristic of each actuator which comprises EPB2 It may be set as appropriate based on the above. FIG. 24 is a diagram showing an example when the brake pad 11 is worn, but it can be changed for each vehicle from what level of wear it is assumed not to be in the normal use region.

FIG. 25 is a flowchart showing details of the current rise gradient norm setting process at the time of current rise. For example, various normative values are set in a state where the brake pads 11 worn at the time of initial shipment are attached. This process is executed as the current increase gradient norm setting process in step 125 of FIG. 4 when such a worn brake pad 11 is attached.

First, in steps 1100 to 1135, processing similar to that in steps 500 to 535 in FIG. 13 is performed. Thereby, the count value T when the count of the rising time elapsed counter is stopped by switching from the state instructed to turn on the rising time elapsed counter to the state instructed to turn off can be acquired. Since this count value T is a value corresponding to the time T ′ taken from the point E ′ to the point F ′ of the motor current value, the routine proceeds to step 1140, where the count value T of the rising time elapsed counter is changed to the current value. The rising time reference value T ′, that is, the current rising gradient reference value is set. In this way, the current increase gradient norm setting process is completed.

First, the outline of the current rising gradient abnormality determination process in this embodiment will be described with reference to FIG.

In the current rising gradient abnormality determination process, it is determined whether or not the rising current gain abnormality has occurred by comparing the current rising gradient at the current current rising time with the current rising gradient norm. Specifically, this determination is performed by comparing the current rise time T at the current rise with the current rise time reference value T ′.

First, the current rise time T at the time of current rise in the current lock control is calculated by the same method as the method for setting the current rise time reference value described above. Specifically, as shown in FIG. 24, when the motor current value becomes the first current monitor value when the current rises, the point E is defined as point F, and the abnormality detection timing is point F as the second current monitor value. The current rise time T is obtained by calculating the time taken to reach the point.

Since this is the current rise time T at the current rise, it is possible to determine whether or not a rise current gain abnormality has occurred by comparing with the preset current rise time reference value T ′. It becomes.

FIG. 26 is a flowchart showing details of the current climb gradient abnormality determination process. When the current increase gradient abnormality determination process shown in step 165 of FIG. 4 is executed, each process shown in FIG. 26 is executed.

First, in steps 1200 to 1235, processing similar to that in steps 1100 to 1135 in FIG. 25 is performed, and the current rise time T is obtained by obtaining the count value T of the rise time elapsed counter. Then, the process proceeds to step 1240 to determine whether or not the current current rise time T is less than the current rise time reference value T ′. That is, it is determined whether or not the current increase gradient at the current current increase is larger than the current increase gradient standard.

If a negative determination is made here, since no rising current gain abnormality has occurred, the routine proceeds to step 1245, where there is no rising current gain abnormality, for example, a flag indicating that a rising current gain abnormality has occurred is reset, and the process is terminated. If an affirmative determination is made, a rise current gain abnormality has occurred, so the routine proceeds to step 1250, where there is a rise current gain abnormality, for example, a flag indicating that a rise current gain abnormality has occurred is set, and the process ends. In this way, it can be determined whether or not a rising current gain abnormality has occurred.

Then, when various abnormality determination processes are executed, the determination result is used in the determination of step 240 in FIG. 5, and any one of the three abnormalities of inrush current gain abnormality, no-load current gain abnormality, and rising current gain abnormality is selected. If there is such an abnormality, the target current value MI # TARGET is corrected accordingly. As a result, the lock operation time required for the motor current value to reach the target current value MI # TARGET is corrected so that the lock control can be appropriately performed even in an abnormal state. You can avoid having to stop.

As described above, an abnormal time when the brake pad 11 is worn out and is no longer in the normal use range can be used as a reference value. In this way, it is possible to detect a rising current gain abnormality without being affected by the material of the brake pad 11.

In addition, although the abnormality detection timing at the time of a current rise is set to one here, as described in the third embodiment, a plurality of abnormality detection timings may be used. Thus, by having two or more abnormality detection timings, it becomes possible to reduce the influence of the change in gradient according to the characteristics of EPB2, and it is possible to detect an abnormality regardless of the characteristics of EPB2. It becomes possible.

(Other embodiments)
In each of the above-described embodiments, a case has been described in which correction is performed so that the lock operation time is lengthened when gain abnormality is detected. This is based on the assumption that the motor current value in the three regions is larger than each standard value. In this case, the lock operation time is reached because the motor current value reaches the target current value earlier than normal. Is corrected to increase the lock operation time. Therefore, on the contrary, when the motor current value in the three regions is smaller than each reference value, the lock operation time may be shortened, for example, the target current value may be corrected to be lower than that in the normal state. In order to realize this, for example, an abnormality detection value for current falling gradient comparison and an abnormality detection value for current rising gradient comparison may be set for each of an upper limit value and a lower limit value.

For example, if the ratio between the current descent gradient at the inrush current and the current descent gradient standard exceeds the upper limit value of the abnormality detection value, the lock operation time is corrected longer, and if it is less than the lower limit value, the lock operation time is corrected shorter. It ’s fine. Similarly, if the ratio between the current rise gradient at the time of current rise and the current rise slope norm exceeds the upper limit value of the abnormal detection value, the lock operation time is corrected longer, and if it is less than the lower limit value, the lock operation time is corrected shorter. Just do it. As for the no-load current value, the lock operation time may be corrected to be longer if the no-load current value upper limit CHiLimit is exceeded, and the lock operation time may be corrected to be shorter if it is less than the no-load current value lower limit CLowLimit.

Further, in addition to the correction of the lock operation time, the driver may be notified that a gain abnormality has occurred through the notification device 27. Thus, the driver can grasp that the gain abnormality has occurred, and can take measures such as repair of the amplifier or the EPB-ECU 9.

In addition, as described in the second embodiment, the abnormality detection value and the variation coefficient are set in consideration of variations due to current monitor variation and pad wear. However, these values may be variable depending on the situation. . For example, these values can be set according to the temperature of the motor 10. As shown in FIG. 1, for example, the motor temperature can be detected based on the detection signal of the temperature sensor 28 provided in the motor 10 input to the EPB-ECU 9.

In each of the above embodiments, the disc brake has been described as an example. However, the brake mechanism integrated with the brake mechanism of the service brake 1 and the pressure mechanism of the EPB 2 is also applied to other types of brake mechanisms such as a drum brake. The present invention can be applied to a brake system that is a pressurizing mechanism. When a drum brake is employed as the brake mechanism, the friction material and the friction target material are a brake shoe and a drum, respectively.

Furthermore, in each of the above embodiments, the EPB-ECU 9 is exemplified as the electronic control means, but the present invention is not limited to this. For example, in the above-described embodiment, the configuration including the ESC-ECU 8 and the EPB-ECU 9 as the control device has been described as an example, but the electronic control unit may be configured by making these as an integral ECU. It may be realized by another ECU.

Further, in the fifth embodiment, the current rise time T required to rise from the first current monitor value to the second current monitor value is adopted as a value corresponding to the current rise gradient, and the current rise time reference T is used as the reference. 'It was set. However, as in the first to fourth embodiments, the current increase gradient itself may be adopted and set as the current increase gradient reference. In this case, since the current rising gradient standard is set in a state where the brake pad 11 is worn, it is normal if the current rising gradient is smaller than the current rising gradient standard. Is small, it can be determined that the rising current gain is abnormal. Of course, as in each of the above embodiments, the ratio of the current rising gradient to the current rising gradient norm (current rising gradient / current rising gradient norm) is calculated, and this ratio is used for current rising gradient comparison. If it is smaller than the abnormality detection value, it may be determined to be normal, and if it is larger, it may be determined that there is a rising current gain abnormality. On the other hand, in the first to fourth embodiments, as in the fifth embodiment, the current rise time T required to rise from the first current monitor value to the second current monitor value as a value corresponding to the current rise gradient. And a current rise time standard T ′ may be set as the standard.

Further, in the fifth embodiment, the case of using the current rising gradient norm set at the time of abnormality when the brake pad 11 is worn has been described. However, the brake pad 11 described in the first to fourth embodiments is in a normal state when the brake pad 11 is not worn. It is also possible to detect the rising current gain abnormality by using both of the set current rising gradient norms.

Note that the steps shown in each figure correspond to means for executing various processes. For example, the part of the EPB-ECU 9 that executes the processes of

steps

110 and 150 is the lock control means, the part that executes the processes of steps 115 to 125 is the normative value setting means, and the part that executes the processes of steps 155 to 165 is The part that executes the processing of the abnormality determining means, step 180 corresponds to the wear determining means, and the part that executes the processing of step 250 corresponds to the correcting means. Although not shown as steps in the figure, a portion of the EPB-ECU 9 that instructs the notification device 27 to display that a gain abnormality has occurred when a gain abnormality is determined is displayed. This corresponds to the instruction means.

DESCRIPTION OF SYMBOLS 1 ... Service brake, 2 ... EPB, 5 ... M / C, 6 ... W / C, 7 ... Actuator, 8 ... ESC-ECU, 9 ... EPB-ECU, 10 ... Motor, 11 ... Brake pad, 12 ... Brake disc , 13 ... caliper, 14 ... body, 14a ... hollow part, 14b ... passage, 17 ... rotating shaft, 17a ... male screw groove, 18 ... propulsion shaft, 18a ... female screw groove, 19 ... piston, 23 ... operation SW, 24 ... Lock / release indication lamp, 25 ... G sensor, 26 ... M / C pressure sensor, 27 ... notification device, 28 ... temperature sensor

Claims

Driving the electric motor (10) generates a pressing force for pressing the friction material (11) against the friction material (12) attached to the wheel, and the friction material (11) and the friction material A parking brake control device that controls the parking brake using a brake system having an electric parking brake (2) that generates a parking brake force by friction with (12),
A lock control means (110) for driving the electric motor (10) by supplying a motor current and pressing the friction material (11) against the friction target material (11) to lock the wheel. 150)
The lock control is executed for setting the reference value, and the change in the motor current value during the lock control is determined by the inrush current at the start of the lock control and the no-load current that becomes a constant value after the inrush current. , Divided into three regions at the time of rising current from the time of no load current, a current descending slope norm serving as a reference value for the descending slope of the motor current value at the time of the inrush current, and the current at the time of the no load current Normative value setting means (115 to 125) for setting a no-load current value norm that serves as a reference value for the motor current value and a current ascending slope norm that serves as a reference value for the ascending slope of the motor current value when the current increases. ,
When performing lock control when actually locking the wheel, based on the motor current value during the lock control, a current descending gradient that is a descending gradient of the motor current value at the inrush current; A no-load current value that becomes the motor current value at the time of no-load current and a current increase gradient that becomes an increase gradient of the motor current value at the time of current increase are calculated, and in each of the three regions, the current decrease gradient and the An abnormality determination means for determining a gain abnormality by comparing with a current descending slope norm, comparing the no-load current value with the no-load current value norm, and comparing the current rising gradient with the current ascending slope norm. (155 to 165)
When the lock control means (150) determines that the gain is abnormal by the abnormality determination means (155 to 165) when actually locking the wheel, the lock control means (150) is a time during which the electric motor (10) is operated. A parking brake control device comprising correction means (250) for correcting a certain lock operation time.
The norm setting means (115 to 125) sets at least the current rising gradient norm by executing the lock control at a normal time before the friction material (11) is worn,
The abnormality determining means (155 to 165) is configured such that the current descending gradient is larger than the current descending gradient norm, the no-load current value is larger than the no-load current value norm, or the current increasing gradient is the current increasing gradient. Gain abnormality due to being larger than the norm, the current falling gradient is smaller than the current descending gradient norm, the no-load current value is smaller than the no-load current value norm, or the current rising gradient is the current rising gradient norm To determine if the gain is abnormal due to
The correction means (250) corrects the lock operation time to be longer when the abnormality determination means (155 to 165) determines that the gain is abnormal due to a large value, and determines that the gain is abnormal due to a small value. The parking brake control device according to claim 1, wherein correction for shortening the lock operation time is sometimes performed.
The norm setting means (115 to 125) stores at least the current rising gradient norm by executing the lock control at the time of abnormality after the friction material (11) is worn, or a design constant. Is set as
The abnormality determining means (155 to 165) is configured such that the current descending gradient is larger than the current descending gradient norm, the no-load current value is larger than the no-load current value norm, or the current increasing gradient is the current increasing gradient. Gain abnormality due to being larger than the norm, the current falling gradient is smaller than the current descending gradient norm, the no-load current value is smaller than the no-load current value norm, or the current rising gradient is the current rising gradient norm Determine if the gain is abnormal due to being smaller,
The correction means (250) corrects the lock operation time to be longer when the abnormality determination means (155 to 165) determines that the gain is abnormal due to a large value, and determines that the gain is abnormal due to a small value. The parking brake control device according to claim 1, wherein correction for shortening the lock operation time is sometimes performed.
When the abnormality determining means (155 to 165) determines that a gain abnormality has occurred, the notification apparatus (27) has a display instruction means for displaying that a gain abnormality has occurred. The parking brake control device according to any one of Items 1 to 3.
Wear determination means (180) for determining wear of the friction material (11),
The wear determination means (180) takes the current increase gradient reference set by the reference value setting means (125) as a value taking into account the variation due to wear of the friction material (11), and further reduces the variation due to the wear. A current rising gradient standard with a value not taken into account is set, and when it is determined that there is no gain abnormality in the abnormality determining means (155), a current rising gradient standard with a value not taking into account the variation due to the current rising gradient and the wear Whether the gain is abnormal is determined by comparing the two, and if it is determined that the gain is abnormal, it is determined that the friction material (11) is worn. The parking brake control device according to claim 1.
The reference value setting means (125) sets a first current increase gradient reference and a second current increase gradient reference for at least two different periods (T1 ′, T2 ′) as the current increase gradient reference,
The abnormality determination means (165) is a period corresponding to each of the first and second current increase gradient norms at the time of the current increase based on a motor current value during lock control when the wheel is actually locked. The first and second current rising gradients that are current rising gradients at (T1, T2) are calculated, and the first and second current rising gradients are compared with the first and second current rising gradient norms, respectively. The parking brake control device according to any one of claims 1 to 5, wherein a gain abnormality is determined by doing so.