Brake system, control method and vehicle

Abstract

The invention discloses a braking system which comprises at least two central controllers and a motor driving circuit, the motor driving circuit is electrically connected with a wheel side motor, and the motor driving circuit is arranged in the central controllers. According to the braking system, the motor driving circuit is arranged in the central controller, so that the integration level and the reliability of the braking system can be improved. The invention further discloses a control method of the braking system and a vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle braking, and in particular relates to a braking system, a control method and a vehicle. Background Art

[0002] The EMB (Electro-Mechanical Brake) braking system is a purely mechanical wire-controlled braking system. As an advanced version of the wire-controlled braking system, it abandons the hydraulic braking circuit and uses a brushless motor-driven mechanical structure to directly control the size of the wheel-end braking force. Because the brushless motor-driven mechanical structure is directly arranged on the wheel-end brake module at the wheel end, the conventional design scheme is to arrange the brushless motor drive circuit on the wheel-end brake. This system architecture design requires at least 4 wheel-end EMB controllers (WCU: Wheel Control Unit) on each vehicle, that is, 4 sets of brushless motor drive circuits. At the same time, in order to respond to the braking force requirements of the whole vehicle and the vehicle dynamic control algorithm, such as ABS (Anti-Lock Braking System, anti-lock braking system), ESC (Electronic Stability Control, electronic stability control system) and other functions, it is necessary to set up an EMB system central controller (CCU: Centre Control Unit) on the whole vehicle. It is used to monitor the dynamic operation of the vehicle and control the stability of the vehicle operation when the vehicle brakes.

[0003] The EMB central controller needs to have fail-operating capabilities, and redundant design is required in the hardware architecture, generally with dual-channel control circuit units. The entire EMB system requires four wheel-end controller circuit units and two central controller circuit units. The advantage of placing the brushless motor drive circuit on the wheel-end brake is that the drive circuit is close to the brushless motor, which facilitates circuit design and signal transmission. However, there is a problem that the wheel-end working environment is harsh and has high requirements for the temperature and vibration resistance of electronic components.

[0004] Therefore, it is desirable to provide an integrated EMB braking system, particularly with regard to how to solve the problem of a harsh working environment when a brushless motor drive circuit and a parking drive circuit are arranged on a wheel-end brake, and improve the reliability of the EMB braking system. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a braking system, the purpose of which is to improve reliability.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: the braking system includes a central controller and a motor drive circuit, the motor drive circuit is electrically connected to the wheel-side motor, at least two central controllers are set, and the motor drive circuit is set in the central controller.

[0007] A parking drive circuit is arranged in the central controller, and the parking drive circuit is arranged to control the parking mechanism.

[0008] A switching circuit is arranged in the central controller, and the switching circuit is electrically connected to the motor driving circuit.

[0009] A computing unit is provided in the central controller, and the computing unit is electrically connected to the switching circuit. The motor driving circuit is configured to be controlled by a computing unit through the switching circuit.

[0010] The calculation unit is provided with at least two paths.

[0011] A sensor circuit is arranged in the central controller, and the calculation unit is electrically connected to the sensor circuit. The calculation unit controls the motor drive circuit according to a sensor signal transmitted by the sensor circuit.

[0012] The sensor circuit is provided with at least two paths.

[0013] A power supply system is provided in the central controller, and at least one power supply system is configured to supply power to the computing unit and the motor drive circuit.

[0014] The present invention also provides a control method for a braking system, comprising:

[0015] The central controller identifies the type of vehicle service brake fault;

[0016] The central controller monitors the brake sensor signal and controls the wheel-end brake module to apply braking force when the set conditions are met;

[0017] The central controller determines the wheel speed status signal of the vehicle, compares the wheel speed status signal with the braking intention signal to preset a value in advance, and the calculation unit sends a signal to the motor drive circuit to control the wheel end brake module to slow down the vehicle with a certain braking force.

[0018] The present invention also provides a vehicle, comprising the braking system.

[0019] The brake system of the present invention arranges the motor drive circuit in the central controller, which can improve the integration and reliability of the brake system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] This specification includes the following drawings, which show the following contents:

[0021] Figure 1 It is a structural schematic diagram of the braking system of the present invention;

[0022] The following are marked in the figure: 1. Wheel-end brake module; 2. Wheel-end brake module with parking mechanism; 3. Motor position sensor (RPS) and wheel speed sensor interface; 4. Pedal travel sensor (PTS) interface; 5. CAN communication interface; 6. First calculation unit; 7. Second calculation unit; 8. First power supply; 9. Second power supply; 10. Switching circuit; 11. Main system power management chip; 12. Auxiliary system power management chip; 13. Driving circuit; 14. Communication network; 15. Central controller. DETAILED DESCRIPTION

[0023] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0024] First, as Figure 1 As shown, an embodiment of the present invention provides a braking system, including a central controller and a motor drive circuit, the motor drive circuit is electrically connected to the wheel-side motor, at least two central controllers are provided, and the motor drive circuit is arranged in the central controller.

[0025] Specifically, in the prior art, the EMB braking system places the wheel-end controller at the wheel-end, and the motor drive circuit is close to the wheel-side motor body, which is convenient for circuit design and signal transmission. Its disadvantages are also obvious. The working environment of the wheel-end is affected by the road environment, and the negative effects of vibration and temperature changes are much higher than those on the vehicle body, which directly leads to a significant increase in the braking failure rate.

[0026] In the embodiment of the present invention, by integrating the motor drive circuit into the central controller, the problem of the poor working environment of the motor drive circuit arranged on the wheel-end brake can be solved. By optimizing the circuit design, reducing the line impedance loss of the long-distance drive circuit high-current loop, and performing redundant switching of the drive circuit, the performance and reliability of the entire EMB system are improved. This can effectively ensure the driving safety of the vehicle. When any single point of the service brake fails, the brake system of the embodiment of the present invention achieves safe braking and parking brake by switching and controlling the backup circuit.

[0027] In the embodiment of the present invention, the central controller refers to the central control ECU (Electronic Control Unit), which may include all the control circuits of the present invention, and may also integrate other functional modules, communication modules and other computing brains in the whole vehicle, and may also be a domain controller.

[0028] like Figure 1 As shown, at least two motor drive circuits are arranged in the central controller, and each motor drive circuit controls the wheel motors of the wheel end brake modules arranged on different wheels respectively, and the wheel motors drive the actuators of the wheel end brake modules to clamp or release the brake discs. Only the wheel motor body, motor position sensor and wheel speed sensor are arranged at the wheel.

[0029] like Figure 1 As shown, a parking drive circuit is provided in the central controller, and the parking drive circuit is configured to drive a parking mechanism of a wheel-end brake module, so that the mechanical part of the parking mechanism is retained at the wheel end, and the parking drive circuit of the parking mechanism is also synchronously moved out to the wheel-end controller, so that the parking drive circuit is integrated in the central controller.

[0030] like Figure 1 As shown, a switching circuit is provided in the central controller, and the switching circuit is electrically connected to all motor drive circuits.

[0031] like Figure 1 As shown, a computing unit is provided in the central controller, and the computing unit is electrically connected to the switching circuit. The motor drive circuit is configured to be controlled by a computing unit through the switching circuit, and the computing unit and the auxiliary circuit in the wheel-end controller do not need to be provided. The computing unit is provided with at least two paths to realize redundant control, and the switching circuit is electrically connected to all computing units. The computing unit can be a microprocessor chip or a dedicated preset program chip. A switching circuit is provided between the computing unit and the motor drive circuit, and the switching circuit is adjusted according to the design scheme of the motor drive circuit. The purpose of the switching circuit is to realize that when a single point failure occurs in the computing unit or a motor drive circuit closely related to the computing unit, it can be switched to another computing unit and a motor drive circuit in a normal state for continued control to ensure the normal operation of the braking system.

[0032] In the embodiment of the present invention, the wheel-side motor is the motor of the wheel-end brake module of the vehicle. The motor of the wheel-end brake module is not limited to one motor on a certain wheel, and a parking motor can also be provided. The wheel-side motor is used to provide a driving force for driving the piston of the wheel-end brake module to move, and is a driving motor that applies a braking force.

[0033] like Figure 1As shown, a sensor circuit is set in the central controller, and the calculation unit is electrically connected to the sensor circuit. The calculation unit controls the motor drive circuit according to the sensor signal transmitted by the sensor circuit, and the calculation unit also controls the parking drive circuit according to the sensor signal transmitted by the sensor circuit. At least two sensor circuits are set.

[0034] like Figure 1 As shown, in an embodiment of the present invention, the sensor circuit includes a brake sensor circuit, a motor position sensor circuit and a wheel speed sensor circuit, and at least two brake sensor circuits are provided. The brake sensor circuit is electrically connected to the brake pedal position sensor (Pedal Travel Sensor, PTS), and the position of the brake pedal is determined by the brake pedal position sensor and a brake intention signal indicating the degree of depression of the brake pedal is generated. The central controller receives the driver's brake intention signal through at least two brake intention sensor circuits. The wheel speed sensor circuit is electrically connected to the wheel speed sensor (Wheel Speed ​​Sensor, WSS), and the wheel speed sensor is used to measure the rotation speed of the wheel of the vehicle during driving. The wheel speed sensor circuit is connected to the central controller to provide the vehicle's motion state in real time. The motor position sensor circuit is electrically connected to the motor position sensor (Rotor Position Sensor, RPS), and the motor position sensor is used to measure the precise position of the rotor of the wheel-side motor.

[0035] The signals generated by the motor position sensor and wheel speed sensor are transmitted from the wheel-side motor to the central controller over a long transmission distance. Setting the motor position sensor circuit and wheel speed sensor circuit in the central controller can optimize the signal quality of the motor position sensor and wheel speed sensor after long-distance transmission.

[0036] The central controller is still connected to the vehicle brake pedal position sensor and maintains redundancy. The vehicle's wheel speed sensor signal processing is also integrated into the central controller together with the corresponding motor drive circuit, which can maintain the braking force of at least 3 wheels (the vehicle has 4 wheels in total) in the event of a single point failure of the hardware in any central controller.

[0037] The switching circuit is configured as at least one group of control switches, and control signals of the control switches are distributed according to the calculation unit. The control signals control the motor drive circuit and the parking drive circuit through the switching circuit.

[0038] The motor drive circuit in the central controller is connected to the switching circuit, and the motor drive circuit is connected to the wheel side motor through the connector, and the wheel side motor can be controlled by a certain computing unit by switching the switch switching circuit configuration.

[0039] The parking drive circuit in the central controller is connected to the switching circuit, and the parking drive circuit is connected to the wheel end brake module through a connector, and the wheel end brake module can be controlled by a certain computing unit by switching the switch switching circuit configuration.

[0040] The motor position sensor circuit and wheel speed sensor circuit in the central controller are connected to the calculation unit. The motor position sensor circuit provides feedback values ​​for precise control of the motor. The wheel speed sensor circuit can provide the vehicle status from the signal obtained from the wheel speed sensor. In addition, combined with the signal transmitted to the calculation unit by the brake sensor circuit, both calculation units can control the motor drive circuit according to the brake sensor circuit and the wheel speed sensor circuit.

[0041] like Figure 1 As shown, the central controller is provided with mutually redundant power supply systems (Power Management IC, PMIC), which are also controlled by the computing unit. At least one power supply system is configured to supply power to one computing unit and the motor drive circuit. The power supply systems do not interfere with each other, and the computing unit performs switch control of power supply respectively. The central controller is provided with two power supply systems, which can reduce the number of power bridge circuits when the brake system supports the power redundancy function.

[0042] In the embodiment of the present invention, a power bridge circuit is provided in the central controller. By integrating the motor drive circuit and the parking drive circuit into the central controller, the number of power bridge circuits can be reduced when the EMB system supports the power redundancy function. (If power redundancy is done in the wheel-end controller, 4 power bridge circuits are required. When integrated into the central controller, only 2 power bridge circuits can be designed).

[0043] In the embodiment of the present invention, Figure 1 As shown, at least two parking drive circuits are set in the central controller. The wheel speed sensor circuit of the vehicle is also integrated into the central controller together with the corresponding motor drive circuit. Even if a single wheel side connection circuit fails at a single point, or if any hardware of the central controller fails at a single point, there is still a calculation unit that controls the motor drive circuit through a switching circuit to ensure that the braking force of at least three wheels is maintained, thereby improving the safety and stability of the vehicle.

[0044] like Figure 1As shown, in an embodiment of the present invention, two central controllers are provided, wherein two computing units, two motor drive circuits, two power supply systems and a switching circuit are provided in one of the central controllers, and the two computing units (the first computing unit and the second computing unit in the figure) provided in the central controller redundantly control the motor drive circuit through the switching circuit, and the two motor drive circuits are switched and controlled after the judgment of the computing unit by setting the received sensor signal, and the two motor drive circuits are respectively controlled by the wheel side motors of the wheel end brake module provided on the two first wheels of the driving vehicle; and two computing units, two motor drive circuits, two parking drive circuits, two power supply systems and a switching circuit are provided in the other central controller, and the two computing units (the first computing unit and the second computing unit in the figure) provided in the central controller redundantly control the motor drive circuit and the parking drive circuit through the switching circuit, and the two motor drive circuits are respectively controlled by the received sensor signal after the judgment of the computing unit, and the two motor drive circuits are respectively controlled by the wheel side motors of the wheel end brake module provided on the two second wheels of the driving vehicle, and the two parking drive circuits are respectively controlled by the parking mechanism provided on the two second wheels of the driving vehicle.

[0045] like Figure 1 As shown, in an embodiment of the present invention, two central controllers are provided, and the two central controllers are connected through a communication network. The two central controllers serve as backups for each other, and the two central controllers communicate in real time. The two central controllers are respectively arranged on the front axle and the rear axle of the vehicle, the first wheel is installed on the front axle, and the second wheel is installed on the rear axle. The central controllers of the front axle and the rear axle respectively control the motor drive circuits corresponding to the wheel-end brake modules provided on the two first wheels and the two second wheels and maintain redundant control functions. The central controller is connected to the wheel-end brake modules provided on the four wheels through wiring harnesses, and the wheel-end brake modules provided on the two second wheels have a parking brake function.

[0046] In the embodiment of the present invention, when any one of the two central controllers receives a brake signal from the brake pedal sensor, the two central controllers will jointly drive the corresponding wheel-side motors to achieve braking. If the circuit for receiving the brake pedal sensor signal of one of the central controllers (set as the first central controller) fails, the other central controller (set as the second central controller) will send brake and other signals to the central controller in real time. At this time, the second central controller is equivalent to the sensor signal receiving circuit backed up by the first central controller. The same applies to the failure of the second central controller.

[0047] The present invention also provides a method for controlling a braking system, comprising the following steps:

[0048] The central controller identifies the type of vehicle service brake fault;

[0049] The central controller monitors the brake sensor signal and controls the wheel-end brake module to apply braking force when the set conditions are met;

[0050] The central controller determines the vehicle's wheel speed status signal, compares the wheel speed status signal with the braking intention signal to preset a value in advance, and the calculation unit sends a signal to the motor drive circuit to control the wheel-end brake module to slow down the vehicle with a certain braking force.

[0051] In the embodiment of the present invention, the service brake fault types include invalid service brake and weakened service brake. The central controller identifies invalid or weakened service brake of the vehicle, calculates the vehicle posture and the driver's intention through the integrated calculation unit, and controls the motor drive circuit to control the safe braking of the vehicle.

[0052] In an embodiment of the present invention, the central controller monitors the continuous changes in the braking intention signal transmitted by the braking sensor circuit, and obtains a calculation result after calculation. Once the calculation result exceeds the set value, the set condition is met, and then the wheel is immediately applied with braking force through the wheel-end braking module controlled by the switching circuit.

[0053] In the embodiment of the present invention, the central controller determines the wheel speed state signal of the vehicle and performs correlation calculation on the wheel speed sensor signal and the brake sensor signal. Then the calculation result is compared with the set threshold value. If the calculation result exceeds the threshold value, the calculation unit will send a control motor drive circuit signal, the wheel side motor will work, and the wheel end brake module will generate a certain braking force to slow down the vehicle; if the calculation result is lower than the threshold value, the wheel side motor will not work.

[0054] Through the above operations, no matter what single point failure occurs in the vehicle's electronic braking system, the braking system can decelerate the vehicle to a standstill and lock the vehicle with a certain parking force.

[0055] In an embodiment of the present invention, during the vehicle deceleration and braking process, the central controller integrates the control circuit of the wheel-side motor to control the wheel-end brake module or release the brake. The central controller can continue to monitor the brake pedal travel signal and ensure the maximum braking force of at least three wheels.

[0056] The braking system and control method of the above structure have the following advantages:

[0057] 1. The motor drive circuit and parking drive circuit in the wheel-end controller of the EMB system are divided into the front wheels and the rear wheels and integrated into the central controllers corresponding to the front wheels and the rear wheels respectively. The braking performance is improved by reusing the single-chip microcomputer in the central controller to complete the EMB system algorithm operation and the control of the brushless motor drive circuit;

[0058] 2. By optimizing the circuit design, the line impedance loss of the long-distance drive circuit high-current loop is reduced, and the long-distance rotor position signal and wheel speed signal are amplified and anti-interference designed. The technical problems caused by the long-distance layout of the brushless motor drive circuit and the brushless motor body can be avoided. Integrating the motor drive circuit into the central controller can also save the MCU chips used in the 4 brushless motor drive circuits. By directly using the high-performance MCU in the central controller to control the drive circuits of the 4 wheel-side motors, on the one hand, the number of MCU chips used in the entire EMB system is reduced, and on the other hand, the transmission delay of the control signal from the central controller to the wheel-end controller and the failure rate of the hardware circuit are reduced;

[0059] 3. The braking system does not require brake fluid, and the hydraulic brake circuit is abandoned, which improves product reliability;

[0060] 4. Reduce the number of electronic components placed in the harsh environment of the wheel end, avoiding the high failure rate of electronic components in high temperature and high vibration environments;

[0061] 5. After integrating the signal processing and actuator drive circuits of the entire EMB system, the delay of the control signal through the CAN and other transmission buses can be reduced, which is beneficial to improving the dynamic response performance of the entire system.

[0062] The present invention also provides a vehicle, comprising the integrated electronic brake system of the above structure. The specific structure of the brake system can be referred to Figure 1 Since the vehicle of the present invention includes the braking system in the above embodiment, it has all the advantages of the above braking system.

[0063] The complete vehicle and vehicles of the present invention include but are not limited to passenger cars and commercial vehicles.

[0064] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A braking system, comprising a central controller and a motor drive circuit, wherein the motor drive circuit is electrically connected to a wheel motor, and wherein: At least two central controllers are provided, and the motor driving circuit is provided in the central controller.

2. The braking system according to claim 1, characterized in that: A parking drive circuit is arranged in the central controller, and the parking drive circuit is arranged to control the parking mechanism.

3. The braking system according to claim 1, characterized in that: A switching circuit is arranged in the central controller, and the switching circuit is electrically connected to the motor driving circuit.

4. The braking system according to claim 3, characterized in that: A computing unit is provided in the central controller, and the computing unit is electrically connected to the switching circuit. The motor driving circuit is configured to be controlled by a computing unit through the switching circuit.

5. The braking system according to claim 4, characterized in that: The calculation unit is provided with at least two paths.

6. The braking system according to claim 4, characterized in that: A sensor circuit is arranged in the central controller, and the calculation unit is electrically connected to the sensor circuit. The calculation unit controls the motor drive circuit according to a sensor signal transmitted by the sensor circuit.

7. The braking system according to claim 6, characterized in that: The sensor circuit is provided with at least two paths.

8. The braking system according to any one of claims 4 to 7, characterized in that: A power supply system is provided in the central controller, and at least one power supply system is configured to supply power to the computing unit and the motor drive circuit.

9. The control method of the brake system according to any one of claims 1 to 8, characterized in that: include: The central controller identifies the type of vehicle service brake fault; The central controller monitors the brake sensor signal and controls the wheel-end brake module to apply braking force when the set conditions are met; The central controller determines the wheel speed status signal of the vehicle, compares the wheel speed status signal with the braking intention signal to preset a value in advance, and the calculation unit sends a signal to the motor drive circuit to control the wheel end brake module to slow down the vehicle with a certain braking force.

10. A vehicle, characterized in that: A braking system comprising any one of claims 1 to 8.

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