Control communication system and method applied to vehicle EMB system and vehicle

Abstract

The invention provides a control communication system and method applied to a vehicle EMB system and a vehicle. According to the system, a central controller respectively supports CAN communication and wireless communication with four wheel end brake controllers. The method comprises the following steps: dividing a wireless communication mode into a normal mode, a slight interference mode and a serious interference mode; in the normal working mode, wireless communication is executed between the communication main bodies, and a frequency hopping function is started; in the slight interference working mode, the frequency hopping function works normally and tries to enter the normal working mode, if the try fails, the current mode is kept, the CAN communication function is started in the current mode, the wireless communication function is tried to be repaired, and in the period, if the wireless signal state is deteriorated, the frequency hopping function enters the serious interference working mode; and in the severe interference working mode, the frequency hopping function works normally and tries to enter the other two working modes, and if the try fails, the current mode is kept. According to the invention, related problems caused by the fact that a communication system architecture of an existing EMB system relates to a front / rear axle controller can be solved.

Description

A control communication system, method, and vehicle applied to a vehicle EMB system Technical Field

[0001] This invention belongs to the field of vehicle electromechanical braking technology, and more specifically, relates to a control and communication system, method and vehicle applied to vehicle EMB system. Background Technology

[0002] With the development trend of automotive electrification and intelligence, braking systems have undergone revolutionary changes. To maximize braking energy recovery and achieve active braking control, it is necessary to decouple braking force from the brake pedal, enabling precise control of friction braking force via electrical signals. Against this backdrop, the EMB (Electromechanical Braking) system emerged. The EMB system completely eliminates the hydraulic circuit; the brake actuator is directly driven by an electric motor to generate clamping force, offering numerous advantages such as fast braking response, high control precision, zero residual drag torque, low energy consumption, long brake lifespan, small system size and weight, easy installation and maintenance, and no brake fluid leakage.

[0003] Currently, the EMB system's communication system primarily adopts an architecture of a central controller + front / rear axle controllers + four wheel-end brake controllers (as shown in Figure 1), using a CAN / CANFD communication scheme. When this communication system is in operation, two CAN communication channels are used: one as the primary communication channel and the other as a redundant backup channel. However, although CAN / CANFD performs excellently in terms of communication reliability, an evaluation at the EMB system architecture level reveals the following areas for optimization: 1. Asynchrony issues caused by CAN bus load: The front / rear axle controllers are each equipped with their own hardware clock circuits, leading to clock asynchrony between the front and rear axle controllers. This clock asynchrony, along with timing variations in the bus load, can result in significant delays (milliseconds) in the control commands issued by the front / rear axle controllers.

[0004] II. Asynchronous issues caused by software logic: For the "central controller + front / rear axle controller + four wheel-end brake controllers" scheme, when the EMB upper-layer software algorithm issues control commands, due to the asynchronous clocks of the front / rear axle controllers, and due to the timing of software logic execution and different operating conditions, there may be asynchronous issues in the output processing and forwarding of the front / rear axle controllers.

[0005] Third, cost issues: The "central controller + front / rear axle controller + four wheel-end brake controllers" solution is relatively expensive.

[0006] IV. Problem of excessive bus load: The current industry product communication rate requirement is 1ms period message, but due to the excessive bus load under this communication rate requirement, a lower frequency message period, such as 5ms period, is used. Summary of the Invention

[0007] In view of this, the present invention provides a control communication system, method and vehicle for use in vehicle EMB systems.

[0008] According to a first aspect of the present invention, a control communication system for a vehicle EMB system is provided, the control communication system comprising a left front wheel brake controller, a right front wheel brake controller, a left rear wheel brake controller, a right rear wheel brake controller, and a central controller; the central controller supports point-to-point CAN communication and point-to-point wireless communication with each wheel brake controller.

[0009] Optionally, the central controller and each wheel-end brake controller are equipped with a CAN transceiver and a wireless transceiver; the CAN transceiver of the central controller is configured to communicate with the CAN transceiver of each wheel-end brake controller, and the wireless transceiver of the central controller is configured to communicate with the wireless transceiver of each wheel-end brake controller.

[0010] Optionally, the control communication system further includes a left front wheel speed sensor, a right front wheel speed sensor, a left rear wheel speed sensor, and a right rear wheel speed sensor; each wheel speed sensor is directly connected to the central controller.

[0011] Optionally, the control communication system further includes a pedal position sensor; the pedal position sensor is directly connected in communication with the central controller.

[0012] Optionally, the control communication system further includes a first power supply unit and a second power supply unit; the first power supply unit simultaneously supplies power to the central controller, the left front wheel brake controller, and the right front wheel brake controller; the second power supply unit simultaneously supplies power to the central controller, the left rear wheel brake controller, and the right rear wheel brake controller.

[0013] According to a second aspect of the present invention, a control communication method for a vehicle EMB system is provided. This control communication method is applied to any of the aforementioned control communication systems for a vehicle EMB system, and specifically includes the following steps: responding to a communication start command, controlling the control communication system to enter a normal operating mode. The normal operating mode includes: the central controller and each wheel-end brake controller periodically detecting the signal quality and packet loss rate of the wireless signal; if both the signal quality and packet loss rate are within normal threshold ranges, then the central controller and each wheel-end brake controller perform wireless communication and initiate frequency hopping during wireless communication; and the central controller and each wheel-end brake controller periodically detecting the fault status of the CAN signal link; if the signal quality or packet loss rate is within a slight interference threshold range, then entering a slight interference operating mode; if the signal quality or packet loss rate is within a severe interference threshold range, then entering a severe interference operating mode; during the operation of the control communication system, the periodic detection operation of the signal quality and packet loss rate of the wireless signal by the central controller and each wheel-end brake controller is continuous.

[0014] Optionally, the slight interference operating mode includes: the frequency hopping function operating normally; after entering this operating mode, timing is performed, and if the wireless signal status recovers to the point where both signal quality and packet loss rate are within the normal threshold range within a predetermined time threshold range, then the normal operating mode is entered; otherwise, the slight interference operating mode is maintained; during the period of maintaining the slight interference operating mode, the CAN communication function is activated, the wireless communication function exits the normal operating mode and enters the attempt repair mode, and the control communication system issues a wireless communication alarm fault signal; during the period of maintaining the slight interference operating mode, if the signal quality or packet loss rate is detected to be within the severe interference threshold range, then the severe interference operating mode is entered.

[0015] Optionally, the severe interference operating mode includes: the frequency hopping function is working normally; after entering this operating mode, a timer is performed, and if the state of the wireless signal is improved within a predetermined time threshold range, the system enters the normal operating mode or the slight interference mode according to the improvement of the wireless signal state; otherwise, the severe interference operating mode is maintained; during the period of maintaining the severe interference operating mode, the CAN communication function is started, the wireless communication function exits the normal operating mode and enters the attempt repair mode, and the control communication system issues a wireless communication failure fault signal.

[0016] Optionally, the frequency hopping function specifically involves frequency hopping between 79 channels between 2.402 GHz and 2.480 GHz, with each channel having a bandwidth of 1 MHz and a channel spacing of 1 MHz.

[0017] According to a third aspect of the present invention, a vehicle is provided, the vehicle including an EMB system, the EMB system including a control communication system of any of the above-described vehicle EMB systems.

[0018] Based on the control and communication system of the present invention applied to the vehicle EMB system, and combined with the corresponding control and communication methods, the following problems existing in the communication system of the current EMB system can be solved: 1. Asynchrony problem caused by CAN bus load: During the entire communication cycle, the working time of the normal working mode is much longer than that of the slightly disturbed working mode and the severely disturbed working mode. Moreover, the normal working mode uses a wireless communication link. For the four time differences between the central controller issuing the command and the four wheel-end brake controllers receiving the command, the time error between the four depends on the consistency of the wireless module hardware, and the software error depends on the task execution cycle in the software (e.g., the maximum error corresponding to a 100us task is 100us). Therefore, the delay error (millisecond level) of the four wheel ends caused by the asynchronous clocks of the front / rear axle controllers and the large bus load can be reduced.

[0019] II. Asynchrony issues caused by software logic: After adopting the "central controller + four wheel-end brake controllers" scheme, when the EMB upper-level software algorithm controls the central controller to issue control commands, since this scheme eliminates the front / rear axle controllers, the four wheel-end brake controllers can directly output control, which can avoid communication asynchrony issues.

[0020] III. Cost Issues: By adopting the "central controller + four wheel-end brake controllers" solution, the cost can be reduced by eliminating the front / rear axle controllers.

[0021] IV. High Bus Load Issue: Using a wireless communication solution can achieve task processing at a frequency of 1ms or higher (e.g., 100us) without affecting the bus load.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The present invention can be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which the same or similar reference numerals are used throughout the drawings to denote the same or similar parts.

[0024] Figure 1 shows a schematic diagram of the architecture of a communication system of a conventional EMB system according to the background art of the present invention; Figure 2 shows a schematic diagram of the architecture of a control communication system of a vehicle EMB system according to an embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to more fully understand the technical solutions of the present invention, exemplary embodiments of the present invention will be described more comprehensively and in detail below with reference to the accompanying drawings. Obviously, the one or more embodiments of the present invention described below are merely one or more specific ways to implement the technical solutions of the present invention, and are not exhaustive. It should be understood that other ways belonging to a general inventive concept can be used to implement the technical solutions of the present invention, and should not be limited to the embodiments described exemplary. Based on one or more embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] Example: Figure 2 shows a schematic diagram of the architecture of the control and communication system of the vehicle EMB system according to an embodiment of the present invention. Referring to Figure 2, the control and communication system of the vehicle EMB system according to an embodiment of the present invention includes a left front wheel brake controller, a right front wheel brake controller, a left rear wheel brake controller, a right rear wheel brake controller, and a central controller; the central controller supports point-to-point CAN communication and point-to-point wireless communication with each wheel brake controller.

[0027] Furthermore, in this embodiment of the invention, the central controller and each wheel-end brake controller are equipped with a CAN transceiver and a wireless transceiver; the CAN transceiver of the central controller is configured to communicate with the CAN transceiver of each wheel-end brake controller, and the wireless transceiver of the central controller is configured to communicate with the wireless transceiver of each wheel-end brake controller.

[0028] Furthermore, the control communication system of this embodiment of the invention also includes a left front wheel speed sensor, a right front wheel speed sensor, a left rear wheel speed sensor, and a right rear wheel speed sensor; each wheel speed sensor is directly connected to the central controller.

[0029] Furthermore, the control communication system of this embodiment of the invention also includes a pedal position sensor; the pedal position sensor is directly connected to the central controller.

[0030] Furthermore, the control and communication system of this embodiment of the invention also includes a first power supply unit and a second power supply unit; the first power supply unit simultaneously supplies power to the central controller, the left front wheel brake controller and the right front wheel brake controller; the second power supply unit simultaneously supplies power to the central controller, the left rear wheel brake controller and the right rear wheel brake controller.

[0031] Specifically, in this embodiment of the invention, the central controller adds a wireless transceiver (e.g., 2.4GHz frequency) to the existing CAN transceiver; similarly, the four wheel-end brake controllers also add wireless transceivers to their existing CAN transceivers. CAN communication is used as a backup for wireless communication, and the wireless communication protocol uses a proprietary protocol (not Bluetooth) to achieve data interaction.

[0032] Accordingly, based on the control communication system applied to the vehicle EMB system in this embodiment of the invention, this embodiment of the invention also proposes a control communication method applied to the vehicle EMB system. This control communication method, applied to the aforementioned control communication system, specifically includes the following steps: In response to a communication start command, the control communication system enters a normal operating mode. The normal operating mode includes: the central controller and each wheel-end brake controller periodically detecting the signal quality and packet loss rate of the wireless signal; if the signal quality and packet loss rate are both within the normal threshold range, then the central controller and each wheel-end brake controller perform wireless communication, and activate frequency hopping during the wireless communication; and the central controller and each wheel-end brake controller... The controller periodically detects the fault status of the CAN signal link. If the signal quality or packet loss rate is within the minor interference threshold range, it enters the minor interference operating mode. If the signal quality or packet loss rate is within the severe interference threshold range, it enters the severe interference operating mode. During the operation of the control and communication system, the periodic detection of the signal quality and packet loss rate of the wireless signal by the central controller and each wheel-end brake controller is continuous. Regardless of whether the current operating mode of the control and communication system is normal operating mode, minor interference operating mode, or severe interference operating mode, the detection of the signal quality and packet loss rate of the wireless signal is continuous.

[0033] Furthermore, in this embodiment of the invention, the slight interference working mode includes: the frequency hopping function working normally; after entering this working mode, timing is performed, and if the wireless signal status recovers to the point where both signal quality and packet loss rate are within the normal threshold range within a predetermined time threshold range, then the normal working mode is entered; otherwise, the slight interference working mode is maintained; during the period of maintaining the slight interference working mode, the CAN communication function is started, the wireless communication function exits the normal working mode and enters the attempt repair mode, and the control communication system issues a wireless communication alarm fault signal; during the period of maintaining the slight interference working mode, if the signal quality is detected to be within the severe interference threshold range or the packet loss rate is within the severe interference threshold range, then the severe interference working mode is entered.

[0034] Furthermore, in this embodiment of the invention, the severe interference working mode includes: the frequency hopping function is working normally; after entering this working mode, a timer is performed, and if the state of the wireless signal is improved within a predetermined time threshold range, the system enters the normal working mode or the slight interference mode according to the improvement of the wireless signal state; otherwise, the severe interference working mode is maintained; during the period of maintaining the severe interference working mode, the CAN communication function is started, the wireless communication function exits the normal working mode and enters the attempt repair mode, and the control communication system sends a wireless communication failure fault signal.

[0035] Furthermore, in this embodiment of the invention, the frequency hopping function specifically involves frequency hopping between 79 channels between 2.402 GHz and 2.480 GHz, with each channel having a bandwidth of 1 MHz and a channel spacing of 1 MHz.

[0036] In this embodiment of the invention, a normal threshold range, a slight interference threshold range, and a severe interference threshold range are set for signal quality. Specifically, the normal threshold range is 0 to -65 dBm, the slight interference threshold range is -70 to -90 dBm, and the severe interference threshold range is -95 to -100 dBm. A hysteresis range of 5 dBm is set for both the normal and slight interference threshold ranges, as well as for both the slight and severe interference threshold ranges. This is to prevent the signal quality range determination result from repeatedly jumping around at the corresponding critical points. In the actual implementation, signal quality detection is continuous. If the signal quality is detected as being within the hysteresis range during the first signal quality detection operation, the range determination is moved downwards. If the signal quality is detected as being within the hysteresis range during subsequent signal quality detection operations, the previous range determination result is used by default. For example, if the detected value is -68 dBm during the first signal quality test, which falls within the hysteresis range between the normal threshold range and the slight interference threshold range, then the signal quality is determined to be within the slight interference threshold range. If the current detected signal quality is -68 dBm, and the previous signal quality range determination result was within the slight interference threshold range, then the current signal quality is still determined to be within the slight interference threshold range. If the current detected signal quality is -68 dBm, and the previous signal quality range determination result was within the normal threshold range, then the current signal quality is determined to be within the normal threshold range.

[0037] In this embodiment of the invention, a normal threshold range, a slight interference threshold range, and a severe interference threshold range are set for the packet loss rate. Specifically, the normal threshold range for the packet loss rate is less than 1.0%, the slight interference threshold range is 1.5% to 3.0%, and the severe interference threshold range is greater than 3.5%. A hysteresis range of 0.5% is set for both the normal and slight interference threshold ranges, as well as for both the slight and severe interference threshold ranges. This is to prevent the packet loss rate range determination result from repeatedly fluctuating at corresponding critical points. In specific implementation, packet loss rate detection is continuous. If the packet loss rate is detected as being within the hysteresis range during the first packet loss rate detection operation, the range determination is moved downwards. If the packet loss rate is detected as being within the hysteresis range during subsequent packet loss rate detection operations, the previous range determination result is used by default. For example, if the packet loss rate is 3.2% during the first packet loss rate detection, which falls within the hysteresis range between the minor interference threshold and the severe interference threshold, then the packet loss rate is determined to be within the severe interference threshold range. If the current packet loss rate is 3.2%, and the previous packet loss rate range determination result was within the minor interference threshold range, then the current packet loss rate is still determined to be within the minor interference threshold range. If the current packet loss rate is 3.2%, and the previous packet loss rate range determination result was within the severe interference threshold range, then the current packet loss rate is determined to be within the severe interference threshold range.

[0038] Specifically, in this embodiment of the invention, a repair attempt mode is involved in both the slight interference operating mode and the severe interference operating mode. The repair attempt mode includes two methods: fast recovery and slow recovery. Fast recovery involves three consecutive attempts, each with a 100ms wait. Slow recovery is a subsequent operation to fast recovery, with each attempt waiting 500ms, with no limit on the number of attempts, until normal operating mode is restored or the ECU is powered off. During the fast recovery phase, a rapid reconnection to the receiver's wireless communication module is attempted. If multiple fast recovery attempts fail, the system enters the slow recovery phase. This configuration is designed to adapt to different interference conditions and improve recovery efficiency.

[0039] Specifically, in this embodiment of the invention, based on the vehicle's wireless communication environment, the wireless communication mode is divided into three types: normal working mode, slight interference working mode, and severe interference working mode. The three modes are described in detail below: I. Normal Wireless Communication Mode 1. The central controller and the four wheel-end brake controllers periodically and in real-time detect the signal quality and packet loss rate of the wireless signal. When both the signal quality and packet loss rate are within the normal threshold range, communication between the central controller and the four wheel-end brake controllers is achieved through a wireless transceiver, thereby enabling functions such as issuing braking commands, uploading command execution status, and uploading fault status.

[0040] 2. The central controller and the four wheel-end brake controllers periodically monitor the fault status of the CAN signal link in real time.

[0041] 3. During normal wireless communication, a frequency hopping algorithm is used, with the communication frequency hopping between 79 channels between 2.402 GHz and 2.480 GHz. Each channel has a bandwidth of 1 MHz, and the channel spacing is 1 MHz. Frequency hopping improves signal quality and reduces packet loss rate. When the signal quality or packet loss rate is within the slight interference threshold range, the system enters a slight interference operating mode.

[0042] 4. If the frequency hopping algorithm cannot reduce the interference of external signals, resulting in the signal quality being within the severe interference threshold range or the packet loss rate being within the severe interference threshold range, the system will enter the severe interference working mode.

[0043] II. Wireless Communication Slight Interference Working Mode: 1. In this mode, the frequency hopping function works normally. If the frequency hopping function can restore the normal working mode within a short time threshold range, then the normal working mode is entered. Otherwise, the slight interference working mode is maintained. At this time, the CAN communication function is started, the wireless communication function exits the normal working mode, and the wireless communication function is in the attempt to repair mode.

[0044] 2. If the frequency hopping algorithm fails to reduce interference, resulting in signal quality or packet loss rate falling within the severe interference threshold range, the system will enter the severe interference working mode.

[0045] 3. In the slight interference mode, the system issues a wireless communication alarm fault signal.

[0046] III. Severe Interference Working Mode for Wireless Communication: 1. In this mode, the frequency hopping function works normally. If the normal working mode or slight interference mode can be restored within a short time threshold range through the frequency hopping function, then the normal working mode or slight interference mode will be entered. Otherwise, the severe interference working mode will be maintained. At this time, the CAN communication function will be started, the wireless communication function will exit the normal working mode, and will be in the attempt to repair mode.

[0047] 2. In severe interference mode, the system issues a wireless communication failure fault signal.

[0048] Accordingly, based on the control and communication system applied to the vehicle EMB system in the embodiments of the present invention, the embodiments of the present invention also propose a vehicle, the vehicle including an EMB system, the EMB system adopting the above-mentioned control and communication system applied to the vehicle EMB system, and the control and communication system adopting the above-mentioned control and communication method applied to the vehicle EMB system.

[0049] While one or more embodiments of the present invention have been described above, those skilled in the art will recognize that the present invention can be implemented in any other form without departing from its spirit and scope. Therefore, the embodiments described above are illustrative and not restrictive, and many modifications and substitutions will be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A control and communication system applied to a vehicle EMB system, characterized in that, It includes a left front wheel brake controller, a right front wheel brake controller, a left rear wheel brake controller, a right rear wheel brake controller, and a central controller; the central controller supports point-to-point CAN communication and point-to-point wireless communication with each wheel brake controller.

2. The control and communication system applied to a vehicle EMB system according to claim 1, characterized in that, The central controller and each wheel-end brake controller are equipped with a CAN transceiver and a wireless transceiver; the CAN transceiver of the central controller is configured to communicate with the CAN transceiver of each wheel-end brake controller, and the wireless transceiver of the central controller is configured to communicate with the wireless transceiver of each wheel-end brake controller.

3. The control and communication system applied to a vehicle EMB system according to claim 1, characterized in that, It also includes a left front wheel speed sensor, a right front wheel speed sensor, a left rear wheel speed sensor, and a right rear wheel speed sensor; each wheel speed sensor is directly connected to the central controller.

4. The control and communication system applied to a vehicle EMB system according to claim 1, characterized in that, It also includes a pedal position sensor; the pedal position sensor is directly connected in communication with the central controller.

5. The control and communication system applied to a vehicle EMB system according to claim 1, characterized in that, It also includes a first power supply unit and a second power supply unit; the first power supply unit simultaneously supplies power to the central controller, the left front wheel brake controller and the right front wheel brake controller; the second power supply unit simultaneously supplies power to the central controller, the left rear wheel brake controller and the right rear wheel brake controller.

6. A control communication method applied to a vehicle EMB system, characterized in that, The control and communication system applied to the vehicle EMB system as described in any one of claims 1-5; The control communication method includes: responding to a communication start command, controlling the control communication system to enter a normal operating mode, wherein the normal operating mode includes: the central controller and each wheel-end brake controller periodically detecting the signal quality and packet loss rate of the wireless signal; if the signal quality and packet loss rate are both within the normal threshold range, the central controller and each wheel-end brake controller perform wireless communication and activate frequency hopping during wireless communication; and the central controller and each wheel-end brake controller periodically detecting the fault status of the CAN signal link; if the signal quality or packet loss rate is within the slight interference threshold range, then entering a slight interference operating mode; if the signal quality or packet loss rate is within the severe interference threshold range, then entering a severe interference operating mode; during the operation of the control communication system, the periodic detection operation of the signal quality and packet loss rate of the wireless signal by the central controller and each wheel-end brake controller is continuous.

7. The control communication method applied to a vehicle EMB system according to claim 6, characterized in that, The slight interference operating mode includes: the frequency hopping function is working normally; after entering this operating mode, a timer is performed, and if the wireless signal status recovers to the point where both signal quality and packet loss rate are within the normal threshold range within a predetermined time threshold range, then the normal operating mode is entered; otherwise, the slight interference operating mode is maintained; during the period of maintaining the slight interference operating mode, the CAN communication function is activated, the wireless communication function exits the normal operating mode and enters the attempt repair mode, and the control communication system issues a wireless communication alarm fault signal; during the period of maintaining the slight interference operating mode, if the signal quality or packet loss rate is detected to be within the severe interference threshold range, then the severe interference operating mode is entered.

8. The control communication method applied to a vehicle EMB system according to claim 7, characterized in that, The severe interference working mode includes: the frequency hopping function is working normally; after entering this working mode, a timer is started, and if the state of the wireless signal is improved within a predetermined time threshold range, the system enters the normal working mode or the slight interference mode according to the improvement of the wireless signal state; otherwise, the severe interference working mode is maintained; during the period of maintaining the severe interference working mode, the CAN communication function is started, the wireless communication function exits the normal working mode and enters the attempt repair mode, and the control communication system issues a wireless communication failure fault signal.

9. The control communication method applied to a vehicle EMB system according to claim 6, characterized in that, The frequency hopping function specifically refers to the communication frequency hopping between 79 channels between 2.402 GHz and 2.480 GHz, with each channel having a bandwidth of 1 MHz and a channel spacing of 1 MHz.

10. A vehicle comprising an EMB system, characterized in that, The EMB system includes the control and communication system of the vehicle EMB system as described in any one of claims 1-5.

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