Control device of electronic parking brake system

Abstract

This invention relates to a control device for an electronic parking brake system, comprising: multiple drive circuits respectively connected to a first motor and a second motor to control the first motor and the second motor, wherein the first motor and the second motor provide driving force to the electronic parking brake; a first MCU having multiple core processors, connected to the first drive circuit and the second drive circuit according to an EPB switch signal, wherein the first drive circuit and the second drive circuit receive a first power supply; and a second MCU having at least one core processor, connected to a third drive circuit, wherein the third drive circuit receives a second power supply. Other embodiments may also be applicable.

Description

Technical Field

[0001] This invention relates to a control device for an electronic parking brake system. Background Technology

[0002] Recently, cars on the market use electronic parking brake (EPB) devices that electronically control the parking brake drive. EPB devices are installed on ordinary disc brakes to perform the parking brake function.

[0003] An electronic parking brake is a device that automatically engages or disengages the parking brake even without the driver's manual operation, through a simple switch operation or the control of an electronic control unit (ECU). This electronic parking brake consists of an actuator and a microcontroller unit (MCU). The actuator drives a motor to generate braking force, and the MCU controls the actuator.

[0004] Recently, with increasing attention on autonomous or electric vehicles, braking systems have evolved to use electronic main turbochargers and other technologies to replace hydraulic systems. As a result, an integrated electronic braking system (IDB) has been developed, combining an anti-lock braking system (ABS) and an electronic stability control system (ESC). This IDB system, in addition to controlling the service brake during normal driving, can also control the parking brake, thus enabling miniaturization and weight reduction of the braking system, while significantly improving stability while providing various functions.

[0005] The IDB system is largely composed of electronic devices. Therefore, to improve the reliability of the electronic parking brake, the ECU, as described above, includes multiple MCUs. Among these MCUs, the main MCU controls all the actuators. Consequently, if the main MCU malfunctions, the actuators may become uncontrollable. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] Embodiments of the present invention, intended to address this existing problem, provide a control device for an electronic parking brake system, additionally configuring an actuator to drive the additionally configured actuator using another MCU when any one of a plurality of MCUs malfunctions.

[0008] In addition, embodiments of the present invention provide a control device for an electronic parking brake system that implements circuit cutoff in any one actuator.

[0009] (II) Technical Solution

[0010] The control device of the electronic parking brake system in an embodiment of the present invention includes: a plurality of drive circuits respectively connected to a first motor and a second motor to control the first motor and the second motor, wherein the first motor and the second motor provide driving force to the electronic parking brake; a first MCU connected to the first drive circuit and the second drive circuit according to an EPB switch signal, wherein the first drive circuit and the second drive circuit receive a first power supply; and a second MCU connected to a third drive circuit, wherein the third drive circuit receives a second power supply.

[0011] In addition, the second drive circuit receives the first power supply when the first switch is in the open state.

[0012] In addition, the third drive circuit receives the second power supply when the second switch is in the open state.

[0013] In addition, the second switch is turned off when the first MCU is operating normally, and turned on when the first MCU has a defect.

[0014] In addition, the second MCU receives the EPB switch signal via in-vehicle communication when the first MCU malfunctions.

[0015] In addition, the third drive circuit also includes a cut-off switch, which is used to prevent the second MCU from malfunctioning when the first MCU is operating normally; the cut-off switch is disposed between the lower arm of the third drive circuit and the ground terminal.

[0016] In addition, the first MCU and the second MCU communicate via a data bus.

[0017] In addition, the first drive circuit and the second drive circuit drive the first motor and the second motor respectively.

[0018] In addition, the third drive circuit drives the second motor.

[0019] In addition, the first MCU has multiple core processors, and the second MCU has at least one core processor.

[0020] In addition, the first MCU and the second MCU are implemented on separate PCBs.

[0021] In addition, when the first MCU malfunctions, the second MCU receives the P lock switch signal through the vehicle's internal communication and activates the second switch to control the third drive circuit.

[0022] In addition, the third driving circuit also includes a cut-off switch, which is disposed between the lower arm of the third driving circuit and the ground terminal; the cut-off switch is activated when the first MCU has a defect.

[0023] In addition, when the first MCU malfunctions, the second MCU receives the WSS sensing signal through the vehicle's internal communication, and based on the wheel speed identified from the WSS sensing signal as 0, turns on the second switch to control the third drive circuit.

[0024] In addition, the third driving circuit also includes a cut-off switch, which is disposed between the lower arm of the third driving circuit and the ground terminal; the cut-off switch is activated when the first MCU has a defect.

[0025] (III) Beneficial Effects

[0026] As described above, the control device of the electronic parking brake system of the present invention is to additionally configure an actuator, and when any one of the multiple MCUs fails, the additionally configured actuator is driven by another MCU, thereby ensuring the redundancy of the electronic parking brake device.

[0027] Furthermore, the control device of the electronic parking brake system of the present invention, as described above, implements a cutoff circuit in any one actuator, which has the effect of preventing the failure of another MCU when multiple actuators are normally driven by any one MCU. Attached Figure Description

[0028] Figure 1 This is a diagram illustrating the schematic structure of an electronic parking brake system according to an embodiment of the present invention.

[0029] Figure 2 It is shown Figure 1 A schematic diagram of the braking device.

[0030] Figure 3 This is a diagram illustrating a schematic structure of the electronic parking brake system according to a first embodiment of the present invention.

[0031] Figure 4 This is a diagram illustrating other operating paths of the electronic parking brake system according to the first embodiment of the present invention.

[0032] Figure 5 This is a diagram illustrating other operating paths of the electronic parking brake system according to the first embodiment of the present invention.

[0033] Figure 6 This is a diagram illustrating a schematic structure of an electronic parking brake system according to a second embodiment of the present invention. Detailed Implementation

[0034] The embodiments of the present invention are provided to more fully inform those skilled in the art. The embodiments described below can be modified in various ways, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to more thoroughly and completely convey the invention to those skilled in the art.

[0035] The terminology used in this specification is for illustrative purposes and is not intended to limit the invention. As used herein, the singular form may include the plural form unless otherwise expressly indicated in the text. Furthermore, the terms "comprising" and / or "including" as used in this specification are intended to specify the presence of the mentioned shapes, numbers, steps, actions, components, constituent elements, and / or combinations thereof, without excluding the presence or addition of more than one other shape, number, action, component, constituent element, and / or combination thereof. As used herein, the term "and / or" includes any one or more of the listed items and all combinations thereof.

[0036] Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings, which schematically illustrate embodiments of the invention. In the drawings, shape deformations can be predicted, for example, based on manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be interpreted as limited to the specific shape of the areas shown in this specification; for example, shape variations occurring during manufacturing should be included.

[0037] Figure 1 This is a diagram illustrating the schematic structure of an electronic parking brake system according to an embodiment of the present invention.

[0038] Reference Figure 1 The electronic parking brake system generally includes: a brake pedal, wheels 101, 103, 105, and 107 of the vehicle, calipers 102, 104, 106, and 108, WSS (wheel speed sensors) 121, 123, 125, and 127, PTS 129, motors 111 and 113, and a braking device 200. The calipers 102, 104, 106, and 108 apply braking force to each wheel 101, 103, 105, and 107. The WSSs 121, 123, 125, and 127 detect the rotational speed of each wheel 101, 103, 105, and 107. The motors 111 and 113 control the actuation of the parking brake. The parking brake is located on the rear wheels 105 and 107 of the vehicle and operates electronically by external force.

[0039] The first wheel 101 and the second wheel 103 are located at the front of the vehicle. A first caliper 102 and a second caliper 104 are formed between the first wheel 101 and the second wheel 103. When an external force is applied to the brake pedal, the first caliper 102 and the second caliper 104 apply braking force to each wheel 101 and 103. The third wheel 105 and the fourth wheel 107 are located at the rear of the vehicle. A third caliper 106 and a fourth caliper 108 are formed between the third wheel 105 and the fourth wheel 107. When an external force is applied to the brake pedal, the third caliper 106 and the fourth caliper 108 apply braking force to each wheel 105 and 107. Simultaneously, a first motor 111 and a second motor 113 are formed. If an external force is applied to the EPB (Electronic Parking Brake) switch, the first motor 111 and the second motor 113 drive the electronically operated parking brake, thereby controlling the drive of the vehicle wheels 105 and 107.

[0040] Additionally, WSS 121, 123, 125, and 127 detect wheel rotation speeds to provide braking force to braking device 200; PTS 129 is a pedal sensor that senses the external force generated on the brake pedal outside the vehicle to provide braking force to braking device 200. Braking device 200 operates calipers 102, 104, 106, and 108 based on signals provided from PTS 129 to apply braking force to each wheel 101, 103, 105, and 107.

[0041] Figure 2 It is shown Figure 1 A schematic diagram of the braking device.

[0042] Reference Figure 2 The braking device 200 may generally include: reservoir 201, master cylinder 203, hydraulic supply device 205, valve circuit 207, MPS 209, and ECU 211.

[0043] A pressurizing medium is stored in reservoir 201, which flows along a flow path to generate pressure. The pressurizing medium flows to the required position according to the adjustment of the valve. Although not shown, a simulated valve is generated in the flow path of reservoir 201 to control the flow of the pressurizing medium between reservoir 201 and master cylinder 203. During normal operation, the simulated valve is open, so the operator can manually operate reservoir 201 and master cylinder 203; in abnormal mode, the simulated valve is closed, and the pressurizing medium in master cylinder 203 is delivered to the valve used to control the wheel cylinder through a backup flow path.

[0044] When the driver depresses the brake pedal, the master cylinder 203 pressurizes and discharges the pressurized medium, such as brake fluid, stored inside. This provides the driver with a reaction force in response to the brake pedal pressure. Simultaneously, the PTS 129 senses the external force generated by the brake pedal outside the vehicle and supplies it to the ECU 211.

[0045] The hydraulic supply device 205 generates hydraulic pressure based on the pedal position and transmits it to the wheel cylinders of wheels 101, 103, 105, and 107 to achieve vehicle braking. To generate the hydraulic pressure, the hydraulic supply device 205 includes a motor. Additionally, the braking device 200 includes an MPS 209. The MPS 209 is a motor position sensor that measures the precise rotational position of the motor in the hydraulic supply device 205 and provides this information to the ECU 211.

[0046] Valve circuit 207 can control multiple pressure relief valves, multiple drain valves, analog valves and shut-off valves, etc. The multiple pressure relief valves control the flow path between the hydraulic supply device 205 and the wheel cylinder, the multiple drain valves control the flow path between the master cylinder 203 and the wheel cylinder, the analog valve is used to generate pedal feel, and the shut-off valve controls the backup flow path between the master cylinder 203 and the wheel cylinder.

[0047] Simultaneously, ECU 211 receives sensing signals from P lock switch 251, EPB switch 253, PTS 129, MPS 209, and multiple WSSs 121, 123, 125, and 127, and performs operations corresponding to the provided sensing signals. More specifically, if the driver presses the brake pedal, PTS 129 senses the degree of brake pedal pressure and provides this information to ECU 211.

[0048] If a P-lock switch signal is received via P-lock switch 251 after the vehicle has stopped, the ECU 211 operates the calipers 102, 104, 106, and 108 formed by the multiple wheels 101, 103, 105, and 107, respectively. More specifically, if a P-lock switch signal is received via P-lock switch 251, the ECU 211 sends a signal to the valve circuit 207 to control multiple pressure relief valves, which control the flow path between the hydraulic supply device 205 and the wheel cylinders.

[0049] ECU 211 receives the speeds of wheels 101, 103, 105, and 107 from WSS 121, 123, 125, and 127 to sense the parking state. Additionally, if an EPB switch signal is received via EPB switch 253 after the vehicle has stopped, ECU 211 operates the first motor 111 and the second motor 113 to control the actuation of the parking brakes formed by the third wheel 105 and the fourth wheel 107 at the rear of the vehicle. Thus, various embodiments utilizing the electronic parking brake system 250 including ECU 211 to ensure vehicle redundancy will be achieved using the following... Figures 3 to 4 Please provide a detailed explanation.

[0050] Figure 3 This is a diagram illustrating a schematic structure of the electronic parking brake system according to a first embodiment of the present invention.

[0051] Reference Figure 3 The electronic parking brake system 250 of the first embodiment of the present invention may include an ECU 211 and motors 111 and 113. The ECU 211 includes an ASIC 310, a first MCU 320, a first drive circuit 371, a second drive circuit 372, a PMIC 340, a second MCU 350, and a third drive circuit 373. The first drive circuit 371 and the second drive circuit 372 are components of actuators that drive motors that generate braking force on wheels 101, 103, 105, and 107. Although not shown, the first MCU 320 and the second MCU 350 respectively include an MCU and a motor driver IC. Furthermore, the MCU in the first MCU 320 has multiple core processors, and the MCU in the second MCU 350 can be implemented by at least one core processor. Additionally, the first MCU 320 and the second MCU 350 can be implemented and operate on separate PCBs.

[0052] PMIC 340 includes a WD counter (hereinafter referred to as "WD"). WD senses the operation of the second MCU 350. If the second MCU 350 is a multi-core processor, PMIC 340 may not include WD. Additionally, a first drive circuit 371 is connected to a first motor 111, and a second drive circuit 372 and a third drive circuit 373 are connected to a second motor 113.

[0053] ASIC 310 and PMIC 340 receive power from the vehicle's battery. ASIC 310 receives a first power source, and PMIC 340 may receive a second power source. The first and second power sources may be output from the same battery or from different batteries, and their voltages may be the same or different. ECU 211 may have a transformer (not shown) that allows the voltages of the first and second power sources output from the same battery to be different.

[0054] ASIC 310 supplies power to the first MCU 320 based on a first power supply, and PMIC 340 supplies power to the second MCU 350 based on a second power supply. Simultaneously, the first power supply is supplied to the first drive circuit 371 and the second drive circuit 372, and the second power supply is supplied to the third drive circuit 373.

[0055] When the first MCU 320 is operating normally, the first switch 381 remains in the open state. The first switch 381 connects the power supply line for the first power source to the second drive circuit 372. During normal operation of the first MCU 320, the motor drive IC in the first MCU 320 receives the EPB switch signal generated by the EPB switch. If the EPB switch signal is received, the first MCU 320 provides the received EPB switch signal to the first drive circuit 371 and the second drive circuit 372 connected to the first MCU 320. Accordingly, the first drive circuit 371 and the second drive circuit 372 respectively control the operation of the connected first motor 111 and second motor 113 to provide driving force to the electronic parking brake configured on the rear wheels of the vehicle.

[0056] As described above, when the first MCU 320 is operating normally, the second switch 382 remains closed, and the cut-off switch 383 remains closed. The second switch 382 connects the power supply line for the second power source to the third drive circuit 373, and the cut-off switch 383 is connected between the lower arm of the third drive circuit 373 and the ground terminal. This prevents the second MCU 350 from connecting to the third drive circuit 373, thereby preventing malfunctions that could cause the second MCU 350 to fail to operate normally when the first MCU 320 is running.

[0057] The first MCU 320 and the second MCU 350 communicate periodically or in real time via a data bus. Based on this, the second MCU 350 checks whether the first MCU 320 has a defect. If the first MCU 320 has a defect, the second switch 382, ​​which connects the power supply line to the second power source and the third drive circuit 373, becomes active, and the disconnect switch 383 becomes active.

[0058] If the second MCU 350 detects a defect in the first MCU 320, it receives the EPB switch signal via CAN communication. In this case, the EPB switch signal is received by the motor drive IC within the second MCU 350. Upon receiving the EPB switch signal, the second MCU 350 provides an EPB switch signal to the third drive circuit 373. Accordingly, the second motor 113, connected to the third drive circuit 373, is activated to provide braking force to the electronic parking brake connected to the second motor 113. This ensures redundancy of the parking brake even if the first MCU 320 malfunctions.

[0059] Figure 4 and Figure 5 Additional embodiments are described, which describe a redundant system in which a second MCU 350 operates if a defect occurs in the first MCU 320 of the electronic parking brake system 250 of the first embodiment.

[0060] exist Figure 4 If a defect occurs in the first MCU 320, the second switch 382, ​​which connects the power supply line to the second power source and the third drive circuit 373, becomes open, and the disconnect switch 383 becomes open. The second MCU 350 can be connected to... Figure 2 The P-lock switch 251 is described in the diagram. The second MCU 350 receives the P-lock switch signal from the P-lock switch 251. Based on the received P-lock switch signal, it operates the second motor 113 connected to the third drive circuit 373, providing driving force to the electronic parking brake connected to the second motor 113. Accordingly, even if the first MCU 320 malfunctions, the redundancy of the parking brake can be ensured.

[0061] exist Figure 5 If a defect occurs in the first MCU 320, the second switch 382, ​​which connects the power supply line to the second power source and the third drive circuit 373, becomes open, and the disconnect switch 383 becomes open. The second MCU 350 then... Figure 2 The described WSSs 121, 123, 125, and 127 receive WSS sensing signals including the speeds of the vehicle's wheels 101, 103, 105, and 107. When the second MCU 350 detects that the wheel speed received from the WSS is 0, it operates the second motor 113 connected to the third drive circuit 373, providing driving force to the electronic parking brake connected to the second motor 113. Accordingly, even if the first MCU 320 malfunctions, parking brake redundancy can be ensured.

[0062] Meanwhile, in the first embodiment of the present invention, the first switch 381, the second switch 382 and the cut-off switch 383 are illustrated as FETs (field-effect transistors) that operate on / off, but they are not limited to this and can also be implemented by relay switches.

[0063] According to one embodiment of the present invention, under normal operating conditions, the first MCU 320 can operate two channels of motors by driving the first drive circuit 371 and the second drive circuit 372. In emergency situations such as a defect in the first MCU 320, one channel of motor can be operated via the third drive circuit 373 connected to the second MCU 350. Furthermore, when the second motor 113 is driven by the third drive circuit 373 connected to the second MCU 350, it is not connected to other drive circuits, thus eliminating the need for the complex switching design of a bridge circuit.

[0064] Figure 6 This is a diagram illustrating a schematic structure of an electronic parking brake system according to a second embodiment of the present invention.

[0065] Reference Figure 6The electronic parking brake system 250 of the second embodiment of the present invention may include an ECU 211 and motors 111 and 113. The ECU 211 includes an ASIC 410, a first MCU 420, a first drive circuit 471, a second drive circuit 472, a PMIC 440, a second MCU 450, and a third drive circuit 473. In this case, the ECU 211 differs from the ECU 211 described in the first embodiment only in that cut-off switches 484 and 485 are added to the first drive circuit 471 and the second drive circuit 472 respectively; other components and operations are the same as or very similar to those in the first embodiment. Therefore, only the structure and operation different from the first embodiment will be described.

[0066] When the first MCU 420 is operating normally, the first switch 481 remains open, connecting the power supply line for the first power source to the second drive circuit 472. During normal operation of the first MCU 420, the motor driver IC within the first MCU 420 receives the EPB switch signal generated by the EPB switch. Upon receiving the EPB switch signal, the first MCU 420 provides the EPB switch signal to the first drive circuit 471 and the second drive circuit 472 connected to the first MCU 420. Accordingly, the first drive circuit 471 and the second drive circuit 472 respectively control the operation of the connected first motor 111 and second motor 113, providing driving force to the electronic parking brake located on the rear wheels of the vehicle. Thus, during normal operation of the first drive circuit 471 and the second drive circuit 472, the respective disconnect switches 484 and 485 connected between the lower arm of the first drive circuit 471 and the ground terminal remain open.

[0067] The first MCU 420 and the second MCU 450 communicate periodically or in real-time via a data bus. Accordingly, the second MCU 450 checks whether the first MCU 420 is defective. If the first MCU 420 is defective, the second switch 482, which connects the power supply line to the second power source and the third drive circuit 473, becomes active, and the cut-off switch 483 becomes active. Furthermore, to prevent malfunctions in the first drive circuit 471 and the second drive circuit 472 during the operation of the third drive circuit 473, the respective cut-off switches 484 and 485 connected to the first drive circuit 471 and the second drive circuit 472 remain closed.

[0068] Meanwhile, in the second embodiment of the present invention, the first switch 481, the second switch 482, and the cut-off switches 483, 484, and 485 are illustrated as FETs (field-effect transistors) that operate on / off. However, they are not limited to this and can also be implemented by relay switches.

[0069] Furthermore, in the first and second embodiments of the present invention, if the second MCUs 350 and 450 are activated when the first MCUs 320 and 420 malfunction, and the vehicle is then started, the status of the first MCUs 320 and 420 is confirmed. If the first MCUs 320 and 420 are functioning normally, the cut-off switches 383 and 483 are switched off. However, if the first MCUs 320 and 420 are still in a defective state after the vehicle is restarted, the operation of the third drive circuits 373 and 473 should be controlled, thus continuously maintaining the open state of the cut-off switches 383 and 483. However, this can be applied differently depending on the manufacturer's requirements.

[0070] This invention is not limited to the embodiments described herein. Various modifications and variations can be implemented without departing from the technical points of this invention, which will be obvious to those skilled in the art.

Claims

1. A control device for an electronic parking brake system, comprising: Multiple drive circuits are connected to the first motor and the second motor respectively to control the first motor and the second motor, and the first motor and the second motor provide driving force to the electronic parking brake. The first MCU is connected to the first driving circuit and the second driving circuit according to the EPB switch signal. The first driving circuit and the second driving circuit receive the first power supply. The second MCU is connected to the third driving circuit, which receives a second power supply. The first drive circuit is connected to the first motor, and the second and third drive circuits are connected to the second motor. The second driving circuit receives the first power supply when the first switch is in the on state, and the third driving circuit receives the second power supply when the second switch is in the on state. The second switch is closed when the first MCU is operating normally. When the first MCU malfunctions, the second MCU receives a signal via the vehicle's internal communication system and activates the second switch to control the third drive circuit. The third driving circuit also includes a cut-off switch, which is used to prevent the second MCU from malfunctioning when the first MCU is operating normally, and to activate the cut-off switch when the first MCU malfunctions. The first MCU and the second MCU communicate periodically or in real time via a data bus, allowing the second MCU to confirm whether the first MCU has a defect. Under normal operating conditions, the first MCU drives the first and second drive circuits to execute motor actions on two channels. When the first MCU malfunctions, the second MCU drives the third drive circuit to execute motor actions on one channel. The disconnect switch is connected between the lower arm of the third drive circuit and the ground terminal. The third driving circuit is not connected to the first driving circuit and the second driving circuit.

2. The control device for the electronic parking brake system according to claim 1, characterized in that, The first driving circuit and the second driving circuit drive the first motor and the second motor, respectively.

3. The control device for the electronic parking brake system according to claim 1, characterized in that, The third drive circuit drives the second motor.

4. The control device for the electronic parking brake system according to claim 1, characterized in that, The first MCU has multiple core processors; The second MCU has at least one core processor.

5. The control device for the electronic parking brake system according to claim 1, characterized in that, The first MCU and the second MCU are implemented on separate PCBs.

6. The control device for the electronic parking brake system according to claim 1, characterized in that, The signal is one of the following: EPB switch signal, P lock switch signal, and WSS sensing signal.

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