KR102121567B1 - Electronic parking brake system in a vehicle and method thereof - Google Patents

Abstract

The present invention is to detect a failure due to a short circuit in the electronic parking brake system to control the vehicle so that the correct current is transmitted to the motor of both wheels according to the operation command of the MCU in the electronic parking brake system.
There is a first motor drive circuit that cuts or supplies power to the first motor and the first motor, and a second motor drive circuit that cuts or supplies power to the second and second motors, and the first motor drive. A short circuit detection unit detecting a short circuit between the circuit and the second motor drive circuit, and an MCU determining a short circuit between the first motor drive circuit and the second motor drive circuit according to the output of the short circuit detection unit; It is an object of the present invention to provide a parking brake system including a display unit warning a user of a short circuit between the first motor drive circuit and the second motor drive circuit.

Description

Vehicle electronic parking brake system and its control method {ELECTRONIC PARKING BRAKE SYSTEM IN A VEHICLE AND METHOD THEREOF}

The disclosed invention relates to an electronic parking brake system for a vehicle and a control method thereof, and more particularly, to a circuit for detecting a circuit failure that may occur in a motor driving circuit in an electronic parking brake system of a vehicle and a method for operating the same It is an invention.

Generally, a brake device includes a parking brake called a normal hand brake or a side brake, which keeps a vehicle in a stopped state. The parking brake is operated by the driver operating a parking lever provided on one side of the driver's seat inside the vehicle. When the driver pulls the parking lever and the cable connected to it is pulled, the brake assembly on the rear wheel side connected to the cable is operated to secure the braking force. On the contrary, the parking lever is released to release the braking force when the cable is released.

However, since the operation method of the parking brake according to the operation of the parking lever is operated only by the driver's will, when the vehicle is parked on a ramp without inadvertently pulling the parking lever, the vehicle may roll down and cause an unexpected accident. You can. In addition, since the driver needs to operate the parking lever at the time of parking or whenever the vehicle is started, the use is very cumbersome, and particularly, the use of the device is more troublesome for women or the elderly who have weak power.

Therefore, in recent years, an electronic parking brake (EPB) system that electronically controls the driving of the parking brake is used, and is mounted on a conventional disc brake to perform the function of the parking brake.

The electronic parking brake system allows the driver to automatically activate or release the parking brake according to a simple switch operation or the control judgment of the electronic control unit governing the overall control even if the driver does not manually operate the parking brake.

The electronic parking brake system is composed of an actuator having a motor that generates a braking force, and an electronic control unit (ECU) for driving the actuator. The ECU consists of an MCU, several sensor interfaces, a motor drive, and a communication module. The electronic control unit (ECU) activates (Apply) or releases (Release) the electronic parking brake system by driving the actuator according to the operating state of the switch. However, in the circuit diagram of the rear left motor and rear right motor of the circuit in the electronic control unit (ECU), there was a problem of failure due to disconnection.

Embodiments of the present invention seek to control the vehicle so that the correct current is transmitted to the motor of both wheels according to the operation command of the MCU in the electronic parking brake system of the vehicle by detecting a failure due to a short circuit between both ends of the motor.

In addition, in order to solve the above-mentioned problem, when a short circuit between both ends of the motor is detected, the user is warned.

According to an aspect of the present invention, a first motor; and a first motor drive circuit that cuts or supplies power supplied to the first motor; and a second motor; cuts or supplies power supplied to the second motor A second motor drive circuit; and a short circuit detection unit detecting a short circuit between the first motor drive circuit and the second motor drive circuit; and the first motor drive circuit and the second motor drive according to the output of the short circuit detection unit. An electronic parking brake system including an MCU for determining a short circuit between the circuits and a display unit warning the user of a short circuit between the first motor drive circuit and the second motor drive circuit may be provided.

In addition, when the power supplied to the first motor and the second motor of the vehicle is cut off, the MCU may determine a short circuit between the first motor drive circuit and the second motor drive circuit.

In addition, the short circuit detection unit may include a first short circuit detection circuit connected to the first motor drive and a second short circuit detection circuit connected to the second motor drive.

Further, the MCU may apply a first voltage to the first short circuit detection circuit, and determine a short circuit between the first motor drive circuit and the second motor drive circuit according to the output of the second short circuit detection circuit. .

In addition, when a first voltage is applied to the first short circuit detection circuit, if the output value of the second short circuit detection circuit is not 0 [V], the MCU may short circuit the first motor drive circuit and the second motor drive circuit. It can be judged as being done.

In addition, the MCU may apply a second voltage to the second short circuit detection circuit and determine a short circuit between the first motor drive circuit and the second motor drive circuit according to the output of the first short circuit detection circuit. .

In addition, when a second voltage is applied to the second short circuit detection circuit, if the output value of the first short circuit detection circuit is not 0 [V], the MCU communicates with the first motor drive circuit.

It may be determined that the second motor drive circuit is shorted.

Embodiments of the present invention, by constructing a circuit diagram for detecting a short circuit in the electronic parking brake system, it is possible to detect in advance that the signal of the MCU is undesirably wrongly transmitted to the right motor and the left motor.

In addition, by constructing a circuit diagram for detecting an error of the electronic parking brake system due to a short circuit in the circuit in the ECU, it is possible to warn the user when an error occurs.

1 is a cross-sectional view of a brake that can be used in one embodiment of the present invention.
2 is a block diagram of an electronic parking brake system according to the present invention.
3 is a short circuit detection circuit diagram of a single motor.
4 is a schematic diagram of a short circuit detection circuit diagram in which a short circuit occurs between motors.
5 is a graph of a voltage change of a motor with time during normal operation.
6 is a graph of a voltage change of a motor over time when a short circuit occurs between motors.
7 is a flowchart illustrating a control method of an electronic parking brake system according to the present invention.

The configuration shown in the embodiments and drawings described in this specification is only a preferred example of the disclosed invention, and at the time of filing of the present application, there may be various modifications that can replace the embodiments and drawings of the present specification.

Hereinafter, a vehicle according to an exemplary embodiment will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a brake that can be used in one embodiment of the present invention.

The brake body is supplied as a cylinder 62 to which hydraulic pressure generated in the master cylinder is supplied, a caliper housing to which pad plates with brake pads 63 and 67 attached to one side are fixed, and a cylinder inserted in a cylinder to be linearly movable. A piston 65 that is linearly moved by hydraulic pressure, a brake plate mounted on the end of the piston, a pad plate to which the brake pads 63 and 67 are attached, and a brake mounted between the two brake pads 63 and 67 and mounted on the drive shaft Disc 68 is included.

The brake piston 65 transmits kinetic force to the brake pad 67 while moving along the rotation axis of the motor.

Inside the brake piston 65, a linkage ring of the electronic parking brake of the motor may be installed.

When the motor 61 of the electronic parking brake rotates, the brake piston 65 performs translational motion in a direction parallel to the rotation axis of the motor. The brake piston 65 moves toward the brake pad 67 and then contacts the brake pad 67 and causes the brake pad 67 to press the brake disc 68.

In addition, when the brake pad 67 located in the same direction as the brake piston 65 among the pair of brake pads 63 and 67 is pressed by the brake piston 65, the brake disc 68 is pressed against the brake disc 68, and the caliper housing is a brake piston. It moves in the opposite direction to the moving direction of (65). At this time, the brake pad 63 on the other side also presses the brake disc 68.

As a result, the pair of brake pads 63 and 67 press the brake discs 68 in both directions to generate a braking force due to friction between the brake pads 63 and 67 and the brake discs 68.

The MCU controlling the operation of the motor on caliper type brake of FIG. 1 and the left and right motor drives will be described later.

2 is a block diagram of an electronic parking brake system according to the present invention, and FIG. 3 is a detailed configuration diagram of an electronic parking brake according to an embodiment of the present invention, and is a circuit diagram of applying a voltage to a single motor. 4 is a schematic diagram of a circuit diagram when a short circuit occurs between motors. In an embodiment of the present invention, an electronic parking brake system of a motor on caliper type will be described as an example.

According to an embodiment of the present invention, the electronic parking brake system includes an MCU 100, a display unit 400, a rear wheel right motor drive 200, a rear wheel left motor drive 300, a right motor (a), and a left motor (b). ), and a short circuit detection unit 23.

The MCU 100 may control the electronic parking brake system as a whole.

The MCU 100 controls on/off of the application SW and the release SW included in the right motor drive 200 and the left motor drive 300, and turns on/off the switch of whether a voltage is applied to the left and right motors a, b. It is possible to control and control the warning signal on the display unit 400.

The MCU 100 may independently control the right motor drive 200 and the left motor drive 300 when driving the electronic parking brakes of the left and right rear wheels.

When the right motor drive 200 receives an operation signal by the MCU 100, the application SW or release SW is turned on to supply power from the first battery BAT1 to the motor.

When the left motor drive 300 receives an operation signal by the MCU 100, it turns on the application switch and release switch to supply power from the second battery BAT2 to the motor.

The short circuit detection unit 23 includes a first short circuit detection circuit 21 and a second short circuit detection circuit 22.

The first short circuit detection circuit 21 is a short circuit detection circuit connected to the right motor drive, and detects a short circuit and transmits the detection result to the MCU.

The signal is applied to the voltage by the MCU 100, and the first short circuit detection circuit 21 may turn on the voltage application switch to detect whether a short circuit has occurred in the circuit in the electronic parking brake system.

The second short circuit detection circuit 22 is a short circuit detection circuit connected to the left motor drive, and detects a short circuit and transmits the detection result to the MCU.

The voltage is applied by the MCU 100, and the second short circuit detection circuit 22 can detect whether a short circuit has occurred in the circuit in the electronic parking brake system by turning on the voltage application switch.

The display unit 400 may warn the user when the voltage value measured at the right motor monitoring point and the left motor monitoring point is different from the expected voltage value and is determined to be malfunctioning.

The display unit 400 may give a visual warning to the user by the display. However, the present invention is not limited thereto, and for example, the acoustic unit may provide an acoustic warning to the user.

There is no case where both the application SW and the release SW are turned on by the MCU 100, and the operation of detecting whether a disconnection in the electronic brake system of the present invention in the state where both the application SW and the release SW are off is described later in FIG. 4. .

When the application SW or release SW is operated, when the application SW is off, the release SW is on and when the application SW is on, the release SW is off. In this case, the magnitude of the voltage that can be measured at the motor monitoring point maximizes the voltage value (Vdd) applied to the motor.

Therefore, it is possible to detect a malfunction due to disconnection of the circuit when both the application SW and the release SW are off.

When both the application switch and the release switch are turned off by the MCU 100, the motor voltage can be measured at the motor monitoring point 33 by turning on or off the applied voltage switch SW.

When the applied voltage switch SW is off, the voltage measured at the motor monitoring point 33 is 0[V] because it is grounded to the ground.

When the applied voltage switch SW is turned on, the voltage value measured at the motor monitoring point 33 is measured according to the voltage distribution of the applied voltage Vdd.

In one embodiment, as shown in FIG. 3, when the motor monitoring point 33 has the same size of the impedance 31 above and below, the voltage value measured at the motor monitoring point is Vdd/2[V].

4 is a schematic diagram of a circuit diagram in which a disconnection (short circuit) occurs between drive motors.

4 includes a left motor circuit and a right motor circuit that are independently controlled by one MCU 100.

The first short circuit detection circuit includes a first applied voltage switch SW1 and a first applied voltage switch SW1 and a first motor monitoring point (node 1) 41 when the first applied voltage switch SW1 is turned on. . In addition, the second short-circuit detection circuit is applied with a voltage value Vdd2[v] when the second applied voltage switch SW2 is on, and the second applied voltage switch SW2 and the second motor monitoring point (node 2) 42 are applied. Includes.

The first applied voltage switch SW1 and the second applied voltage switch SW2 operate oppositely by the MCU 100. For example, when the first applied voltage switch SW1 is turned on, the second applied voltage switch SW2 is turned off. Further, when the first applied voltage switch SW1 is off, the second applied voltage switch SW2 is turned on.

Since the left motor circuit and the right motor circuit are independently controlled by the MCU 100, the motor applied voltage Vdd1[v] of the left motor circuit is connected to the right motor circuit by a short circuit of the first applied voltage switch SW1 during normal operation. It does not affect. Further, during normal operation, the motor applied voltage Vdd2[v] of the right motor circuit does not affect the left motor circuit due to the short circuit of the second applied voltage switch SW2.

In the electronic parking brake system according to the present embodiment, when a malfunction occurs due to disconnection in the circuit diagram, it can be regarded as a case in which a short circuit between the left motor and the right motor in FIG. 4 appears.

The method of detecting a malfunction according to the paragraph in FIG. 4 will be described in detail below.

When the first applied voltage switch SW1 is turned on and the second applied voltage switch SW2 is turned off, the expected voltage of the second motor monitoring point (node 2) 42 is 0[v] because Vdd2 is not applied. However, the measured voltage is a case where the first motor monitoring point (node 1) 41 is disconnected. If the measured voltage of the first motor monitoring point (node 1) 41 is not 0 [v], this is the left right motor drive. It can be considered that a disconnection between the circuits 200 and 300 has occurred.

In addition, when the second applied voltage switch SW2 is turned on and the first applied voltage switch SW1 is turned off, the expected voltage of the first motor monitoring point (node 1) 41 is 0[deg.] because Vdd1 is not applied. v], but the measured voltage is the case where the second motor monitoring point (node 2) 42 is disconnected. If the measured voltage of the second motor monitoring point (node 2) 42 is not 0 [v], this is the left right. It can be considered that a disconnection between the motor drive circuits 200 and 300 has occurred.

5 is a graph of a change in voltage of a motor with time during normal operation, and FIG. 6 is a graph of a change of motor voltage with time when a short circuit between motors occurs.

The first motor monitoring point (node 1) 41 and the second motor monitoring point (node 2) 42 of FIG. 4 are contacts for measuring the voltage of the motor, and in the case of the embodiment described below, half of the applied voltage (Vdd1/ 2,Vdd2/2) is measured to be normal operation. Further, the applied voltages Vdd1 and Vdd2 may be the same.

In normal operation, when the first applied voltage switch (SW1) is on, the measured voltage of the first motor monitoring point (node 1) 41 of the motor 1 is Vdd1/2[v]. At this time, since the second applied voltage switch SW2 is off, the measured voltage of the second motor monitoring point (node 2) 42 of the motor 2 in normal operation is 0 [v].

In addition, in the case of normal operation, when the second applied voltage switch (SW2) is on, the measured voltage of the second motor monitoring point (node 2) 42 of the motor 2 is Vdd2/2[v]. At this time, since the first applied voltage switch SW1 is off, the measured voltage of the first motor monitoring point (node 1) 41 of the motor 1 during normal operation is 0 [v].

The first motor monitoring point (node 1) 41 and the second motor monitoring point (node 2) 42 of FIG. 5 are contacts for measuring the voltage of the motor, and in the case of the embodiment described below, half of the applied voltage (Vdd1) /2,Vdd2/2) is measured to be normal operation.

However, when a short circuit occurs between the first motor and the second motor, the normal voltage according to the operation of the applied voltage switch is not measured.

The voltage values of the applied voltages Vdd1 and Vdd2 can be set identically.

In FIG. 5, when the second applied voltage switch SW2 is turned on, the measured voltage of the second motor monitoring point (node 2) of the motor 2 is Vdd2/2[v]. At this time, since the first applied voltage switch SW1 is off, the measured voltage of the first motor monitoring point (node 1) 41 of the motor 1 in normal operation should be 0[v], but with a disconnection in this drawing. Therefore, the first motor monitoring point (node 1) 41 and the second motor monitoring point (node 2) 42 become the same contact, and the measured voltage of the first motor monitoring point (node 1) 41 of the motor 1 The value of Vdd2/2 whose value is not 0 [v] is measured. Therefore, it may be determined as a malfunction.

7 is a flowchart illustrating a control method of an electronic parking brake system according to the present invention.

According to the present embodiment, the electronic parking brake device determines whether the first motor and the second motor are operating (10). That is, when the electronic parking brake of the present application is applied or released by the MCU 100, it is an operating state of the brake. When the brake is in the operating state 10, the flow chart is restarted.

When the first motor and the second motor do not operate (No of 10), the first applied voltage switch is turned on and the second applied voltage switch is turned off (20).

Specifically, when the brake is not applied or released, there is room for the brake to be interpreted as being applied.

Thereafter, the voltages of the first motor monitoring point (node 1) and the second motor monitoring point (node 2) are measured, and whether the voltage measured at the first motor monitoring point (node 1) is Vdd1/2 and the second motor It is determined whether the voltage measured at the monitoring point (node 2) is 0 [v]. (30)

Unless the voltage measured at the first motor monitoring point (Node 1) is Vdd1/2[v], and the voltage measured at the second motor monitoring point (Node 2) is 0[v] (No of 20) Since it is a malfunction due to disconnection between the 1 motor and the 2 motor, it warns the driver (60).

If the voltage measured at the first motor monitoring point (Node 1) is Vdd1/2, and the voltage measured at the second motor monitoring point (Node 2) is 0[V] (example of 20), Vdd1 is turned off, and Vdd2 is turned off. Comes on (40).

Then, the voltages of the first motor monitoring point (node 1) and the second motor monitoring point (node 2) are measured, and whether the voltage measured at node 1 is Vdd1/2 [V] and the voltage measured at node 2 It is determined whether it is 0[V] (50).

If the voltage measured at the second motor monitoring point (Node 2) is Vdd2[v], and the voltage measured at the first motor monitoring point (Node 1) is 0[v] (example of 50), normal operation Ends with.

If the voltage measured at the second motor monitoring point (Node 2) is Vdd2[v], and the voltage measured at the first motor monitoring point (Node 1) is not 0[v] (no of 50), between motors The circuit diagram is disconnected and malfunctions and warns (60).

In the above, one embodiment of the disclosed invention has been shown and described, but the disclosed invention is not limited to the specific embodiments described above, and has ordinary knowledge in the technical field to which the disclosed invention belongs without departing from the gist of the claims Of course, various modifications are possible, and such modifications are not individually understood from the disclosed invention.

100: MCU 400: display
200: right motor drive 300: left motor drive
a: right motor b: left motor
2: Circuit diagram of the left motor 3: Circuit diagram of the right motor
41: first motor monitoring point (node 1)
42: second motor monitoring point (node 2)
31: Impedance
21: first short circuit detection circuit 22: second short circuit detection circuit
23: short circuit detection section
61: electronic booster

Claims (7)

A first motor;
A first motor drive circuit that cuts or supplies power supplied to the first motor;
A second motor;
A second motor drive circuit that cuts or supplies power supplied to the second motor;
A short circuit detecting unit detecting a short circuit between the first motor drive circuit and the second motor drive circuit;
An MCU that determines a short circuit between the first motor drive circuit and the second motor drive circuit according to the output of the short circuit detection unit;
And a display unit configured to warn the user of a short circuit between the first motor drive circuit and the second motor drive circuit. According to claim 1,
When the power supplied to the first motor and the second motor of the vehicle is cut off, the MCU determines the short circuit between the first motor drive circuit and the second motor drive circuit. According to claim 2,
The short circuit detector includes an electronic parking brake system including a first short circuit detection circuit connected to the first motor drive and a second short circuit detection circuit connected to the second motor drive. According to claim 3,
The MCU applies a first voltage to the first short circuit detection circuit and determines an electric short circuit between the first motor drive circuit and the second motor drive circuit according to the output of the second short circuit detection circuit. . The method of claim 4,
When a first voltage is applied to the first short circuit detection circuit, if the output value of the second short circuit detection circuit is not 0 [V], the MCU indicates that the first motor drive circuit and the second motor drive circuit are short circuited. Judging electronic parking brake system. According to claim 3,
The MCU applies a second voltage to the second short circuit detection circuit, and an electronic parking brake system for determining a short circuit between the first motor drive circuit and the second motor drive circuit according to the output of the first short circuit detection circuit. . The method of claim 6,
When a second voltage is applied to the second short circuit detection circuit, if the output value of the first short circuit detection circuit is not 0 [V], the MCU indicates that the first motor drive circuit and the second motor drive circuit are short circuited. Judging electronic parking brake system.

Images