Electronic mechanical braking system for control redundancy, and wheel end braking apparatus and electric vehicle

Abstract

Provided in the present application are an electronic mechanical braking system, a wheel end braking apparatus and an electric vehicle. The electronic mechanical braking system comprises two central controllers and four wheel end braking apparatuses, wherein the two central controllers correspond to two braking pedal sensors on a one-to-one basis, each central controller is used for receiving a braking pedal signal that is output by the braking pedal sensor corresponding to the central controller, and the braking pedal signal is used for indicating a motion state of a braking pedal; and the four wheel end braking apparatuses are used for outputting braking force to brake an electric vehicle. In the electronic mechanical braking system provided in the present application, braking control redundancy of the electric vehicle is realized by means of providing the two braking pedal sensors and the two central controllers, and when one of the sensors or one of the central controllers fails, the electronic mechanical braking system can still accurately brake the electric vehicle, thereby improving the braking safety and reliability of the electronic mechanical braking system.

Description

Control of redundant electromechanical brake systems, wheel-end brakes and electric vehicles

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 28, 2023, with application number 202311851784.4 and application name “Controlled redundant electronic mechanical braking system, wheel-end braking device and electric vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of electric vehicle braking, and in particular to an electronic mechanical braking system with redundant control, a wheel-end braking device, and an electric vehicle. Background Art

[0003] Electronic mechanical braking systems have developed rapidly due to their advantages of fast response speed and high control accuracy. However, the use of electrical signals for control places higher functional safety requirements on electronic mechanical braking systems. However, most electric vehicles on the market are currently equipped with only one wire-controlled brake system. Equipping only with one wire-controlled brake system will increase the risk of car driving. If the brake pedal sensor or central controller in the electronic braking system fails, it will cause brake failure, posing a great risk to the normal and safe driving of the electric vehicle. Summary of the Invention

[0004] The present application provides an electronic mechanical braking system, a wheel-end braking device and an electric vehicle, which are used to solve the problem of brake failure caused by single-point failure of the brake pedal sensor or central controller of the electronic mechanical braking system, thereby improving the operating reliability and safety of the electronic mechanical braking system.

[0005] In a first aspect, the present application provides an electromechanical braking system comprising two central controllers and four wheel-end brake devices. The two central controllers correspond one-to-one with two brake pedal sensors, each central controller being configured to receive a brake pedal signal output by its corresponding brake pedal sensor, the brake pedal signal being configured to indicate the movement state of the brake pedal. The four wheel-end brake devices are configured to output a braking force to brake the electric vehicle.

[0006] The electronic mechanical braking system provided by the present application includes two brake pedal sensors that serve as backups for each other and two central controllers that serve as backups for each other. On the one hand, the two brake pedal sensors can more accurately detect the movement state of the brake pedal. On the other hand, if one of the brake pedal sensors fails, the other brake pedal sensor can still independently detect the movement state of the brake pedal, thereby improving the operational reliability of the electronic mechanical braking system. The electromechanical braking system provided by the present application includes two central controllers, which include a master central controller and a slave central controller. When the master central controllers are normal, the master central controller is responsible for controlling the output braking force of the four wheel-end brake devices. When the master central controller fails abnormally, the slave central controller can continue to control the output braking force of the four wheel-end brake devices, thereby avoiding the failure of the entire electronic mechanical braking system due to the failure of the central controller, thereby improving the safety and reliability of the braking system.

[0007] In one embodiment of the first aspect, the two brake pedal sensors include a first brake pedal sensor and a second brake pedal sensor, and the two central controllers include a first central controller and a second central controller. The first central controller is configured to receive a first brake pedal signal output by the first brake pedal sensor, and the second central controller is configured to receive a second brake pedal signal output by the second brake pedal sensor. The first central controller is a master central controller, and the second central controller is a slave central controller. In response to the first central controller being valid and at least one of the first brake pedal signal and the second brake pedal signal being valid, the first central controller is configured to control the braking force output by the four wheel-end brake devices. In response to the first central controller being invalid and the second central controller being valid, the second central controller is configured to control the braking force output by the four wheel-end brake devices.

[0008] The electronic mechanical braking system provided by this application controls the four wheel-end braking devices through the first central controller when the first central controller is active. If the first central controller fails, the second central controller further controls the four wheel-end braking devices. The two central controllers of the electronic mechanical braking system provided by this application serve as backup for each other, thereby improving the braking reliability and safety of the electronic mechanical braking system.

[0009] In one embodiment of the first aspect, the first brake pedal signal and the second brake pedal signal are used to indicate brake pedal travel. In response to the first brake pedal signal and the second brake pedal signal being both valid, the first central controller is configured to control the four wheel-end brake devices to output braking force based on the brake stroke signal indicating the larger brake pedal travel. In response to the first brake pedal signal and the second brake pedal signal being valid, the first central controller is configured to control the four wheel-end brake devices to output braking force based on the valid brake pedal signal. If the first central controller and the first brake pedal signal and the second brake pedal signal are both valid, the first central controller controls the four wheel-end brake devices to output braking force based on the brake pedal signal indicating the larger brake pedal travel of the two brake pedal signals, thereby ensuring that the wheel-end brake devices can output sufficient braking force to ensure a safe and reliable braking process.

[0010] In one embodiment of the first aspect, in response to a first brake pedal signal being valid, the first central controller is configured to control the four wheel-end brake devices to output braking forces based on the first brake pedal signal. In response to a first brake pedal signal being invalid and a second brake pedal signal being valid, the first central controller is configured to receive a second brake pedal signal from the second central controller and control the four wheel-end brake devices to output braking forces based on the second brake pedal signal.

[0011] In this embodiment, if both the first central controller and the first brake pedal signal are valid, the first central controller can directly control the braking force output by the wheel-end brake devices based on the first brake pedal signal. This shortens the signal transmission path and improves the response speed and control accuracy of the electromechanical brake system. However, if the first central controller is valid, the second central controller is valid, the first brake pedal signal is invalid, and the second brake pedal signal is valid, the first central controller needs to obtain the second brake pedal signal from the second central controller and then control the braking force output of the four wheel-end brake devices based on the second brake pedal signal.

[0012] In one embodiment of the first aspect, in response to the first central controller failing, the second central controller being valid, and the second brake pedal signal being valid, the second central controller controls the four wheel-end brake devices to output braking force based on the second brake pedal signal. In response to the first central controller failing, the second central controller being valid, the first brake pedal signal being valid, and the second brake pedal signal failing, the second central controller is configured to receive the first brake pedal signal from the first central controller and control the four wheel-end brake devices to output braking force based on the first brake pedal signal.

[0013] If the first central controller fails and the second central controller is valid, the second central controller will be required to control the braking force output of the four wheel-end brake devices. In this case, if the second brake pedal signal is valid, the second central controller can directly control the braking force output of the four wheel-end brake devices based on the second brake pedal signal. However, if the second brake pedal signal fails and the first brake pedal signal is valid, the second central controller must first obtain the first brake pedal signal from the first central controller and then control the braking force output of the four wheel-end brake devices based on the first brake pedal signal.

[0014] In one embodiment of the first aspect, the two brake pedal sensors include a first brake pedal sensor and a second brake pedal sensor, and the two central controllers include a first central controller and a second central controller. The first central controller is configured to receive a first brake pedal signal output by the first brake pedal sensor, and the second central controller is configured to receive a second brake pedal signal output by the second brake pedal sensor. In response to the first central controller being valid and the first brake pedal signal being valid, the first central controller is configured to control the braking force output by the four wheel-end brake devices based on the first brake pedal signal. In response to the second central controller being valid, the second brake pedal signal being valid, and either the first central controller or the first brake pedal signal being invalid, the second central controller is configured to control the braking force output by the four wheel-end brake devices based on the second brake pedal signal.

[0015] In one embodiment of the first aspect, during braking of the electric vehicle, in response to both the first brake pedal signal and the second brake pedal signal failing and the first central controller being active, the first central controller controls the four wheel-end brake devices to output a fixed braking force. In response to both the first brake pedal signal and the second brake pedal signal failing, the first central controller failing, and the second central controller being active, the second central controller controls the four wheel-end brake devices to output a fixed braking force. The fixed braking force is the braking force corresponding to a preset brake pedal opening, where the preset pedal opening is greater than 50%.

[0016] If both the first and second brake pedal signals fail, it's difficult to determine the braking force required to control the four wheel-end brakes based on brake pedal travel. To ensure braking safety, the central controller will control the wheel-end brakes to output a larger, fixed braking force. This fixed braking force corresponds to a pedal opening greater than 50%. The fixed braking force can be stored as a numerical value in both central controllers. When both the first and second brake pedal signals fail, the central controller can adjust the fixed braking force to control the four wheel-end brakes to output this fixed braking force.

[0017] In one embodiment of the first aspect, each wheel-end braking device includes a wheel-end controller and a brake actuator, the wheel-end controller is used to receive a brake control signal and control the brake actuator to output a braking force indicated by the brake control signal, and the wheel-end controller is used to control the brake actuator to output a fixed braking force in response to the failure of both the first central controller and the second central controller.

[0018] In the event that both the first central controller and the second central controller fail, each wheel-end brake device can respond independently, that is, the wheel-end controller of each wheel-end brake device controls the brake actuator to output a fixed braking force.

[0019] In one embodiment of the first aspect, the first central controller and the second central controller each include a housing, the housing including a public CAN communication interface and a private CAN communication interface. The first central controller receives signals from the second central controller via the public CAN communication interface, the second central controller receives signals from the first central controller via the public CAN communication interface, and the first and second central controllers send signals to the four wheel-end controllers via the private CAN communication interface or receive signals from the four wheel-end brake devices via the private CAN communication interface.

[0020] In one embodiment of the first aspect, the signal exchanged between the first central controller and the second central controller includes a brake pedal sensor valid position signal, which is used to indicate whether the brake pedal signal is valid or invalid.

[0021] In a second aspect, the present application provides a wheel-end braking device for an electric vehicle, comprising a wheel-end controller and a brake actuator. The wheel-end controller is configured to control the brake actuator to output a braking force to a brake disc of the electric vehicle. The wheel-end controller is configured to output the braking force in accordance with instructions from a first central controller or a second central controller. The first central controller is configured to receive a first brake pedal signal from a first brake pedal sensor, and the second central controller is configured to receive a second brake pedal signal from a second brake pedal sensor. In response to the first central controller being active and the first brake pedal signal being active, the wheel-end controller is configured to control the brake actuator to output the braking force in accordance with instructions from the first central controller.

[0022] The wheel-end braking device provided in the present application can output braking force according to the instructions of the first central controller, and can also output braking force according to the instructions of the second central controller. In the event that one of the first central controller and the second central controller fails, the wheel-end braking device can still output braking force normally to brake the electric vehicle. The wheel-end braking device provided in the present application can improve the braking safety and reliability of the electric vehicle.

[0023] In one embodiment of the first aspect, the wheel-end controller responds to the second central controller and the second brake pedal signal being valid and at least one of the first central controller and the first pedal signal being invalid, and the wheel-end controller is used to control the brake actuator to output braking force according to the instructions of the second central controller.

[0024] In one embodiment of the first aspect, the wheel-end controller is used to control the brake actuator to output a fixed braking force in response to the failure of both the first central controller and the second central controller or the failure of both the first brake pedal signal and the second brake pedal signal. The fixed braking force is the braking force indicated when the brake pedal opening is a preset opening, and the preset pedal opening is greater than 50%.

[0025] When the first central controller and the second central controller are unable to control the wheel-end braking device to output braking force, the wheel-end braking device provided in the present application can output a larger fixed braking force to brake the electric vehicle. That is to say, the wheel-end braking device provided in the present application can still provide emergency braking force for the electric vehicle when the control system fails, thereby further improving the braking safety and braking reliability of the electric vehicle.

[0026] In one embodiment of the first aspect, the wheel-end controller includes a control circuit and a power circuit, the brake actuator includes a brake motor and a brake caliper, the power circuit includes a three-phase bridge arm, the brake motor includes a three-phase winding, the midpoints of the three-phase bridge arms of the power circuit are respectively used to connect the three-phase windings of the brake motor, the control circuit is used to control the power circuit to output a brake motor drive current to the three-phase windings of the brake motor, and the brake motor drive current is used to control the brake motor to drive the brake caliper to clamp the brake disc.

[0027] In a third aspect, the present application provides an electric vehicle, which includes an electronic mechanical braking system and a drive system as described in any one of the first aspects, the drive system including a drive motor and a motor controller. During the braking process of the electric vehicle, the electronic mechanical braking system is used to output driving braking force, and the drive motor outputs negative torque as the wheels of the electric vehicle rotate to output feedback braking force.

[0028] The beneficial effects of the wheel-end braking device provided in the third aspect of the present application are as described in the beneficial effects of the electronic mechanical braking system provided in the first aspect of the present application, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0030] FIG2 is a schematic diagram of an electromechanical braking system provided in an embodiment of the present application;

[0031] FIG3 is a schematic structural diagram of a wheel-end brake device provided in an embodiment of the present application;

[0032] FIG4 is a schematic diagram of a wheel-end controller provided in an embodiment of the present application;

[0033] FIG5 is a control architecture diagram of an electromechanical braking system provided in an embodiment of the present application;

[0034] FIG6 is a communication architecture diagram of an electromechanical braking system provided in an embodiment of the present application;

[0035] FIG7 is a schematic diagram of the housing structure of the central controller provided in an embodiment of the present application;

[0036] FIG8 is a schematic diagram of the operation of the electromechanical braking system provided in an embodiment of the present application;

[0037] FIG9 is a schematic diagram of a normal mode operation of an electromechanical braking system provided by an embodiment of the present application;

[0038] 10a to 10d are schematic diagrams of the single-point failure mode operation of the electromechanical braking system provided by an embodiment of the present application;

[0039] FIG11 a and FIG11 b are schematic diagrams showing the operation of the double-point failure mode of the electromechanical braking system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context. References to "one embodiment" or "some embodiments" described in this specification mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Thus, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "comprise", "have" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0041] The electronic mechanical braking system has various advantages such as simple layout and fast response, and has become the main direction of future braking system technology development. However, since the electronic mechanical braking system eliminates hydraulic connections and uses electrical signal transmission, it has higher requirements for functional safety. At present, most autonomous vehicles on the market are equipped with only one set of control systems. Equipping only one set of control systems will increase the risk of driving a car. If the central controller or brake pedal sensor in the system fails, it will cause brake failure, causing huge safety risks in the driving of the autonomous vehicle. Based on the above problems, the present application provides an electronic mechanical braking system, a wheel-end braking device and an electric vehicle.

[0042] Figure 1 is a schematic diagram of an electric vehicle 01 according to an embodiment of the present invention. Referring to Figure 1 , the electric vehicle 01 includes an electromechanical braking system 10 and four wheels 20. During braking of the electric vehicle 01, the electromechanical braking system 10 is used to provide braking force to the four wheels 20.

[0043] Figure 2 is a schematic diagram of an electromechanical braking system 10 provided in an embodiment of the present application. As shown in Figure 2, the electromechanical braking system 10 comprises two brake pedal sensors, two central controllers, and four wheel-end brake devices 13. Each brake pedal travel sensor is configured to output a brake pedal signal, which indicates the state of the brake pedal. The two central controllers correspond one-to-one with the two brake pedal sensors. Each central controller receives a brake pedal signal from its corresponding brake pedal sensor, and one of the central controllers controls the braking force output by the four wheel-end brake devices 13 in response to the brake pedal signal.

[0044] Further referring to Figure 2, the two brake pedal sensors include a first brake pedal sensor PTS1 and a second brake pedal sensor PTS2, and the two central controllers include a first central controller 121 and a second central controller 122. The first brake pedal sensor PTS1 is connected to the first central controller 121, and the second brake pedal sensor PTS2 is connected to the second central controller 122. The first central controller 121 is used to receive the first brake pedal signal output by the first brake pedal sensor PTS1, and the second central controller 122 is used to receive the second brake pedal signal output by the second brake pedal sensor.

[0045] The first brake pedal sensor (PTS1) and the second brake pedal sensor (PTS2) can be either brake pedal displacement sensors or brake pedal pressure sensors. The brake pedal displacement sensor monitors the angle of the brake pedal. The central controller calculates the brake pedal travel based on the angle of the brake pedal sensor, which in turn determines the braking force required by electric vehicle 01001. The brake pedal pressure sensor monitors the pressure applied to the brake pedal. The central controller calculates the braking travel based on the pressure applied to the brake pedal, which in turn determines the braking force required by electric vehicle 01001. Furthermore, the first brake pedal sensor (PTS1) and the second brake pedal sensor (PTS2) can also be other types of sensors.

[0046] The electronic mechanical braking system 10 provided in this application includes two mutually backed-up brake pedal sensors and two mutually backed-up central controllers. On the one hand, the two brake pedal sensors can more accurately detect the movement state of the brake pedal. On the other hand, if one of the brake pedal sensors fails, the other brake pedal sensor can still independently detect the movement state of the brake pedal, thereby improving the operational reliability of the electronic mechanical braking system 10. The electromechanical braking system provided in this application includes two central controllers, including a master central controller, i.e., a first central controller 121, and a slave central controller, i.e., a second central controller 122. When the master central controllers are functioning normally, the master central controller is responsible for controlling the braking force output of the four wheel-end brake devices 13. If the master central controller fails abnormally, the slave central controller can continue to control the braking force output of the four wheel-end brake devices 13, thereby avoiding failure of the entire electronic mechanical braking system 10 due to failure of the central controllers and improving the safety and reliability of the braking system.

[0047] FIG3 is a schematic structural diagram of the wheel-end braking device 13 provided in an embodiment of the present application. As shown in FIG3 , the wheel-end braking device 13 includes a wheel-end controller 133 and a brake actuator 131. The brake actuator 131 includes a brake motor 1311 and a brake caliper 1312. During the braking process of the electric vehicle 01, the wheel-end controller 133 controls the brake motor 1311 to drive the brake caliper 1312 to clamp the brake disc 14 of the electric vehicle 01, thereby providing braking force for the electric vehicle 01. The specific structure of the wheel-end braking device 13 is not limited to the structure shown in FIG3 , and may also be various other possible structures.

[0048] Figure 4 is a schematic diagram of the wheel-end controller structure provided by an embodiment of the present application. As shown in Figure 4, the wheel-end controller includes a control circuit and a brake motor power circuit. The brake motor power circuit includes a three-phase bridge arm, and the brake motor 1311 includes a three-phase winding. The midpoints of the three-phase bridge arms of the power circuit are respectively connected to the three-phase windings of the brake motor. The control circuit is used to control the power circuit to output the brake motor drive current to the three-phase windings of the brake motor 1311. The brake motor drive current is used to control the brake motor 1311 to drive the brake caliper 1312 to clamp the brake disc 14.

[0049] Figures 5 and 6 further show the communication control architecture diagram of the electronic mechanical braking system 10. As shown in Figures 5 and 6, the first central controller 121 and the second central controller 122 are both connected to the public CAN network of the electric vehicle 01. The first central controller 121 and the second central controller 122 can communicate with each other through the public CAN network, or directly through a hard-wired connection. In addition, the first central controller 121 and the second central controller 122 can also communicate with other controllers of the electric vehicle 01 through the public CAN network. For example, the first central controller 121 and the second central controller 122 can communicate with the whole vehicle controller. For electric vehicles 01 with energy recovery function, the required energy recovery intensity of the electric vehicle 01 can be calculated through the interaction between the whole vehicle controller and the electronic mechanical braking system 10.

[0050] The four wheel-end controllers communicate with the central controller via the chassis' private CAN network. The two central controllers can send brake control signals to the wheel-end controllers via the chassis' private CAN network, thereby controlling the braking force output by the wheel-end brakes 13. Furthermore, the four wheel-end controllers can send status signals of the wheel-end brakes 13 to the two central controllers via the chassis' private CAN network, such as the current temperature of the brake motor 1311, the current torque output by the brake motor 1311, and the clamping force status signal output by the brake caliper 1312.

[0051] The first central controller 121 and the second central controller 122 both include a housing, and the housing structure of the central controller is shown in FIG7 . The housing includes a public CAN communication interface, a private CAN communication interface, and a power supply interface. The first central controller 121 and the second central controller 122 communicate with each other via the public CAN communication interface. The second central controller 122 receives signals from the first central controller 121 via the public CAN communication interface, and the first central controller 121 receives signals from the second central controller 122 via the public CAN communication interface. The first central controller 121 and the second central controller 122 send signals to the four wheel-end controllers via the private CAN communication interface or receive signals from the four wheel-end brake devices 13 via the private CAN communication interface. The central controller receives power from a low-voltage battery via the power supply interface.

[0052] It is important to note that the signals exchanged between the first central controller 121 and the second central controller 122 include the brake pedal sensor valid position signal and the central controller valid position signal. The signals sent by the first central controller 121 and the second central controller 122 to the four wheel-end controllers also include the brake pedal sensor valid position signal and the central controller valid position signal.

[0053] The brake pedal sensor valid position signal is used to indicate whether the brake pedal signal is valid or invalid. The central controller valid position signal is used to indicate whether the central controller is valid or invalid.

[0054] Taking the first central controller 121 as an example, the first central controller 121 can determine whether the first brake pedal sensor PTS1 is valid based on the first brake pedal signal transmitted from the first brake pedal sensor PTS1 and output a brake pedal sensor valid position signal. When the brake pedal sensor valid position signal generated by the first central controller 121 indicates a valid state, the first brake pedal signal is valid, meaning that braking decisions can be made based on the first brake pedal signal. When the brake pedal sensor valid position signal generated by the first central controller 121 indicates a failed state, the first brake pedal signal is failed, meaning that braking decisions cannot be made based on the first brake pedal signal. The first central controller 121 then transmits the brake pedal sensor valid position signal to the second central controller 122 and the four wheel-end controllers, thereby informing the second central controller 122 and the four wheel-end controllers of the current validity state of the first brake pedal signal.

[0055] On the other hand, the first central controller 121 can also monitor its own status and generate a central controller valid bit signal. When the first central controller 121 can operate normally, the central controller status indicated by the central controller valid bit signal output by the first central controller 121 is valid. When the central controller cannot operate normally, such as a single board failure or a power failure, the central controller status indicated by the central controller valid bit signal output by the first central controller 121 is invalid, indicating that the central controller cannot operate normally at this time. Similarly, the first central controller 121 will send the central controller valid bit signal to the second central controller 122 and the four wheel-end controllers, thereby informing the second central controller 122 and the four wheel-end controllers of the current valid status of the first central controller 121. The second central controller 122 can also generate a brake pedal sensor valid bit and a central controller valid bit signal, thereby informing the first central controller 121 and the four wheel-end controllers of the second brake pedal signal and whether the second central controller 122 is valid.

[0056] In one embodiment, when the first central controller 121 fails, the first central controller 121 loses the ability to communicate with the second central controller 122. That is, when the second central controller 122 or the four wheel-end controllers cannot receive signals from the first central controller 121, the second controller and the four wheel-end controllers will determine that the first central controller 121 has failed. Similarly, when the first central controller 121 or the four wheel-end controllers cannot receive signals from the second central controller 122, the second central controller 122 and the four wheel-end controllers will determine that the first central controller 121 has failed.

[0057] Figure 8 is a schematic diagram of signal transmission in the electromechanical brake system 10 according to an embodiment of the present application. As shown in Figure 8 , signals are transmitted between the first brake pedal sensor and the first central controller 121 via channel 1. Specifically, after collecting the brake pedal motion state signal, the first brake pedal sensor PTS1 transmits the first brake pedal signal to the first central controller 121 via channel 1.

[0058] The second brake pedal sensor and the second central controller 122 transmit signals via channel 2 . After collecting the motion state signal of the brake pedal, the second brake pedal sensor PTS2 sends the second brake pedal signal to the second central controller 122 via channel 2 .

[0059] The first central controller 121 communicates with the four wheel-end controllers via channel 3. The signals sent by the four wheel-end controllers to the first central controller 121 via channel 3 include wheel-end status signals and wheel-end controller valid position signals. The wheel-end status signals indicate the current state of the wheel-end brake device 13, specifically including the temperature of the brake motor 1311, the rotor position angle of the brake motor 1311, and the clamping force output by the brake actuator 131. The wheel-end controller valid position signal indicates whether the wheel-end controller is valid or invalid. The second brake pedal sensor valid position signal indicates whether the second brake pedal signal is valid or invalid. The signals sent by the first central controller to the wheel-end controllers include the central controller valid position signal and the first brake pedal sensor valid position signal.

[0060] The second central controller 122 communicates with the four wheel-end controllers via channel 4. The communication between the second central controller 122 and the four wheel-end controllers is the same as the communication between the first controller 121 and the four wheel-end controllers.

[0061] The first central controller 121 and the second central controller 122 communicate via the public CAN network of the electric vehicle 01. Signals exchanged between the first central controller 121 and the second central controller 122 include a brake pedal sensor valid position signal, a central controller valid position signal, and the like. Specifically, the first central controller 121 is configured to send a first brake pedal sensor (PTS1) valid position signal and a first central controller (121) valid position signal to the second central controller 122, indicating the valid status of the first brake pedal sensor (PTS1) and the valid status of the first central controller 121, respectively. The second central controller 122 is configured to send a second brake pedal sensor (PTS2) valid position signal and a second central controller (122) valid position signal to the first central controller 121, indicating the valid status of the second brake pedal sensor (PTS2) and the valid status of the second central controller 122, respectively.

[0062] Channel 1, Channel 2, Channel 3, and Channel 4 are the paths for signal transmission. The specific form depends on the connection method between the modules, such as hard-wire connection, CAN bus connection, etc.

[0063] The electronic mechanical braking system 10 provided in the embodiment of the present application is provided with two brake pedal sensors and two central controllers, thereby realizing a redundant design of the control system. The electronic mechanical braking system 10 provided in the embodiment of the present application can still accurately control the four wheel-end brake devices 13 to provide braking force when a single-point failure occurs in the brake pedal sensor or the central controller, thereby improving the safety and reliability of the braking of the electric vehicle 01. According to the different failure conditions of the two brake pedal sensors and the two central controllers, the electronic mechanical braking system 10 provided in the embodiment of the present application has corresponding different operating modes to ensure that the electronic mechanical braking system 10 can work reliably. The different operating modes of the electronic mechanical braking system 10 are introduced in detail below in conjunction with specific embodiments.

[0064] 1. Normal mode

[0065] When both brake pedal sensors and both central controllers are functioning normally, the electromechanical brake system 10 is in normal operating mode. At this point, the states indicated by the valid bit signals of the brake pedal sensors of the first central controller 121 and the second central controller 122 are both valid. In this case, the present embodiment provides the following control scheme:

[0066] In one embodiment, the first central controller 121 controls the braking force output of the four wheel-end brakes according to the first brake pedal signal. The first central controller 121 provided in the embodiment of the present application is a master central controller, and the second central controller 122 is a slave central controller. When both brake pedal signals and both central controllers are valid, the first central controller 121 performs the master control function. At this time, the first central controller 121 calculates the brake pedal stroke according to the first brake pedal signal, and then calculates the required vehicle braking force according to the brake pedal stroke and distributes the braking force to obtain the braking force required to be output by each wheel-end brake device 13 and output a braking control signal. In response to the braking control signal, the control circuit in the wheel-end controller 133 controls the power circuit of the brake motor 1311 to output the corresponding brake motor drive current to drive the brake motor to output the braking torque. In turn, the brake motor 1311 drives the brake caliper 1312 to clamp the brake disc 14 of the electric vehicle 01 to output the braking force indicated by the braking control signal.

[0067] The first central controller 121 directly controls the four wheel-end brake devices 13 to output braking forces according to the first brake pedal signal, which can shorten the signal path and improve the control speed and control efficiency during the braking process.

[0068] In one embodiment, in response to both the first brake pedal signal and the second brake pedal signal being valid, the first central controller 121 is configured to control the four wheel-end brake devices 13 to output braking force based on the brake stroke signal indicating the larger brake pedal stroke. The first brake pedal signal and the second brake pedal signal are used to indicate brake pedal stroke. When both brake pedal signals are valid, the first central controller 121 can directly receive the first brake pedal signal and receive the second brake pedal signal from the second central controller 122. The first central controller 121 compares the first brake pedal signal and the second brake pedal signal and then controls the four wheel-end brake devices 13 to output braking force based on the brake stroke signal indicating the larger brake pedal stroke. This ensures braking safety and avoids insufficient output braking force due to the measurement accuracy of the first brake pedal sensor PTS1.

[0069] FIG. 9 shows a situation where the electromechanical brake system 10 is in a normal mode.

[0070] 2. Single Point Failure Mode

[0071] The so-called single point failure refers to the failure of one of the two brake pedal signals or one of the two central controllers. At this time, the electronic mechanical brake still retains some brake pedal motion state monitoring capabilities or partial control capabilities to ensure that the electronic mechanical brake system 10 continues to work normally. Specifically, the specific circumstances of the single point failure and the corresponding control methods are introduced in detail below in combination with specific embodiments.

[0072] 1. Single brake pedal signal failure (both central controllers are valid)

[0073] In one embodiment, as shown in FIG10 a , the first brake pedal signal is valid and the second brake pedal signal is invalid. At this time, the first central controller 121 controls the four wheel-end brake devices 13 to output braking force according to the first brake pedal signal.

[0074] In one embodiment, as shown in FIG10c , when the first brake pedal signal is valid and the second brake pedal signal is invalid, two control modes are possible. In the first control mode, the first central controller 121 obtains the second brake pedal signal from the second central controller 122 and controls the braking force output of the four wheel-end brake devices 13 based on the second brake pedal signal. In the second control mode, the second central controller 122 directly controls the braking force output of the four wheel-end brake devices 13 based on the second brake pedal signal.

[0075] 2. Single central controller failure (both brake pedal signals are valid)

[0076] In one embodiment, the first central controller 121 fails and the second central controller 122 is valid. At this time, the second central controller 122 controls the four wheel end brake devices 13 to output braking force according to the second brake pedal signal.

[0077] In one embodiment, the first central controller 121 is valid and the second central controller 122 is invalid. In this case, the control method of the first central controller 121 is similar to the above case and will not be described in detail here.

[0078] 3. Single brake pedal signal and single central controller failure

[0079] In one embodiment, as shown in FIG10 b , the first brake pedal signal and the first central controller 121 fail. At this time, the second central controller 122 controls the four wheel-end brake devices 13 to output braking force according to the second brake pedal signal.

[0080] In one embodiment, as shown in FIG10 d , the second brake pedal signal and the second central controller 122 fail. At this time, the first central controller 121 controls the four wheel-end brake devices 13 to output braking force according to the first brake pedal signal.

[0081] From the above analysis, it can be seen that the electronic mechanical braking system 10 provided in the embodiment of the present application is provided with two brake pedal sensors and two central controllers. Each central controller can receive two brake pedal signals, so that when any brake pedal signal fails or any central controller fails, the electronic mechanical braking system 10 can still accurately control the vehicle braking, thereby improving the safety and reliability of the electronic mechanical braking system 10.

[0082] 3. Double-point failure mode

[0083] If the pedal sensor signals output by both brake pedal sensors fail or both central controllers fail, neither central controller will be able to determine the brake pedal travel or calculate and control the braking force output by the four wheel-end brake devices 13 based on the brake pedal travel. In this case, to ensure braking safety, the four wheel-end devices will each output a fixed braking force to ensure braking safety.

[0084] 1. Both brake pedal signals fail

[0085] In one embodiment, as shown in FIG11 a , the brake pedal signals output by the two brake pedal sensors are both invalid but the two central controllers are both valid. In this case, the first central controller 121 is used to control the four wheel-end brake devices 13 to output a fixed braking force.

[0086] In one embodiment, the brake pedal signals output by the two brake pedal sensors are both invalid and one of the two central controllers is invalid. At this time, the central controller in the valid state is used to control the four wheel-end brake devices 13 to output a fixed braking force.

[0087] If both the first and second brake pedal signals fail, it's difficult to determine the braking force required to be controlled by the four wheel-end brake devices 13 based on the brake pedal travel. In this case, to ensure braking safety, the central controller will control the wheel-end brake devices 13 to output a larger fixed braking force. This fixed braking force corresponds to a pedal opening greater than 50%. The fixed braking force can be stored as a numerical value in both central controllers. When both the first and second brake pedal signals fail, the central controller can adjust the fixed braking force to control the four wheel-end brake devices 13 to output this fixed braking force.

[0088] 2. Both central controllers fail

[0089] In one embodiment, as shown in FIG11b , both central controllers fail, for example, due to a single board failure or power failure in both central controllers, causing both central controllers to malfunction, and the four wheel-end brake devices 13 can now autonomously output a fixed braking force.

[0090] Specifically, when both central controllers fail, the state indicated by the central controller valid bit signal sent by the two central controllers to the wheel-end controller through the chassis private CAN is failure, or the communication between the two central controllers and the four wheel-end controllers is interrupted due to a fault. The wheel-end controller controls the brake actuator 131 to output a fixed clamping force so that a fixed braking force is generated between the brake caliper 1312 and the brake disc 14 to brake the electric vehicle 01.

[0091] 3. One brake signal and one central controller fail.

[0092] In one embodiment, the first brake pedal signal fails and the second central controller 122 fails. In this case, the first central controller 121 controls the four wheel-end brake devices 13 to output a fixed braking force.

[0093] In one embodiment, the second brake pedal signal and the first central controller 121 fail. In this case, the second central controller 122 controls the four wheel-end brake devices 13 to output a fixed braking force.

[0094] From the above analysis, it can be seen that the electronic mechanical braking system provided in the embodiment of the present application can still output a fixed braking force when both brake pedal signals or both central controllers fail, thereby controlling the electric vehicle to stop, thereby preventing the electric vehicle from losing control, and further improving the safety and reliability of the braking system and the electric vehicle.

[0095] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations thereof may be made without departing from the scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are intended to cover any and all modifications, variations, combinations or equivalents within the scope of the present application.

[0096] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. An electronically-mechanical braking system for controlling redundancy, characterized in that, The electro-mechanical braking device includes two central controllers and four wheel-end braking devices, where: The two central controllers correspond to two brake pedal sensors one by one. Each central controller is configured to receive a brake pedal signal output by the corresponding brake pedal sensor, and the brake pedal signal is used to indicate the movement state of the brake pedal; The four wheel-end braking devices are configured to output braking force to brake the electric vehicle.

2. The electromechanical braking system according to claim 1, wherein The two brake pedal sensors include a first brake pedal sensor and a second brake pedal sensor. The two central controllers include a first central controller and a second central controller. The first central controller is configured to receive a first brake pedal signal output by the first brake pedal sensor, and the second central controller is configured to receive a second brake pedal signal output by the second brake pedal sensor; The first central controller is configured to: In response to the first central controller being valid and at least one of the first brake pedal signal and the second brake pedal signal being valid, control the four wheel-end braking devices to output braking force; The second central controller is configured to: In response to the first central controller failing and the second central controller being valid, control the four wheel-end braking devices to output braking force.

3. The electromechanical braking system according to claim 2, wherein, The first brake pedal signal and the second brake pedal signal are used to indicate the brake pedal travel. The first central controller is configured to: In response to both the first brake pedal signal and the second brake pedal signal being valid, control the four wheel-end braking devices to output braking force according to the brake travel signal with a larger indicated brake pedal travel, In response to one of the first brake pedal signal and the second brake pedal signal being valid, control the four wheel-end braking devices to output braking force according to the valid brake pedal signal.

4. The electromechanical braking system according to claim 2, wherein, The first central controller is configured to: In response to the first brake pedal signal being valid, control the four wheel-end braking devices to output braking force according to the first brake pedal signal; In response to the first brake pedal signal failing, the second brake pedal signal being valid, and the second central controller being valid, receive the second brake pedal signal from the second central controller and control the four wheel-end braking devices to output braking force according to the second brake pedal signal.

5. The electromechanical braking system according to claim 2, wherein The second central controller is configured to: In response to the first central controller failing, the second central controller being valid, and the second brake pedal signal being valid, control the four wheel-end braking devices to output braking force according to the second brake pedal signal.

6. The electromechanical braking system according to claim 1, characterized in that, The two brake pedal sensors include a first brake pedal sensor and a second brake pedal sensor. The two central controllers include a first central controller and a second central controller. The first central controller is configured to receive a first brake pedal signal output by the first brake pedal sensor, and the second central controller is configured to receive a second brake pedal signal output by the second brake pedal sensor; The first central controller is configured to: In response to the first central controller being valid and the first brake pedal signal being valid, control the four wheel-end braking devices to output braking force according to the first brake pedal signal; The second central controller is configured to: In response to the second central controller being valid, the second brake pedal signal being valid, and any one of the first central controller and the first brake pedal signal failing, control the four wheel-end braking devices to output braking force according to the second brake pedal signal.

7. The electromechanical braking system according to any one of claims 2-6, characterized in that, During the braking process of the electric vehicle, the first central controller is configured to: In response to both the first brake pedal signal and the second brake pedal signal failing and the first central controller being valid, control the four wheel-end braking devices to output a fixed braking force; The second central controller is configured to: In response to both the first brake pedal signal and the second brake pedal signal failing, the first central controller failing, and the second central controller being valid, control the four wheel-end braking devices to output the fixed braking force; The fixed braking force is the braking force corresponding to a preset opening degree of the brake pedal, and the preset pedal opening degree is greater than 50%.

8. The electromechanical braking system according to claim 7, characterized in that, Each of the wheel-end braking devices includes a wheel-end controller and a brake actuator. The wheel-end controller is configured to receive the braking control signal and control the brake actuator to output the braking force indicated by the braking control signal. The wheel-end controller is configured to: In response to both the first central controller and the second central controller failing, control the brake actuator to output the fixed braking force.

9. The electromechanical braking system according to any one of claims 1-8, characterized in that, Both the first central controller and the second central controller include a housing, and the housing includes a public CAN communication interface and a private CAN communication interface; The first central controller receives signals from the second central controller through the public CAN communication interface; The second central controller receives signals from the first central controller through the public CAN communication interface; The first central controller and the second central controller send signals to the four wheel-end controllers through the private CAN communication interface or receive signals from the four wheel-end braking devices through the private CAN communication interface.

10. The electromechanical braking system according to claim 9, wherein The signals exchanged between the first central controller and the second central controller include a brake pedal sensor valid bit signal, and the brake pedal sensor valid bit signal is used to indicate whether the brake pedal signal is valid or invalid.

11. A wheel-end braking device for an electric vehicle, characterized in that, The wheel-end braking device includes a wheel-end controller and a brake actuator. The wheel-end controller is configured to control the brake actuator to brake the brake disc of the electric vehicle. The wheel-end controller is configured to output braking force according to the instruction of the first central controller or the second central controller. The first central controller is configured to receive a first brake pedal signal from a first brake pedal sensor, and the second central controller is configured to receive a second brake pedal signal from a second brake pedal sensor. The first brake pedal signal and the second brake pedal signal are used to indicate the movement state of the brake pedal of the electric vehicle. The wheel-end controller is configured to: In response to the first central controller being valid and the first brake pedal signal being valid, control the brake actuator to output a braking force according to the instruction of the first central controller.

12. The wheel-end braking device according to claim 11, wherein, The wheel-end controller is configured to: In response to the second central controller being valid, the second brake pedal signal being valid, and at least one of the first central controller and the first pedal signal being invalid, control the brake actuator to output a braking force according to the instruction of the second central controller.

13. The wheel-end braking device according to claim 11 or 12, characterized in that, The wheel-end controller is configured to: In response to both the first central controller and the second central controller failing or both the first brake pedal signal and the second brake pedal signal failing, control the brake actuator to output a fixed braking force, where the fixed braking force is the braking force indicated when the brake pedal opening is a preset opening, and the preset pedal opening is greater than 50%.

14. The wheel-end braking device according to any one of claims 11-13, characterized in that, The wheel-end controller includes a control circuit and a power circuit. The brake actuator includes a brake motor and a brake caliper. The power circuit includes three-phase bridge arms. The brake motor includes three-phase windings. The midpoints of the three-phase bridge arms of the power circuit are respectively used to connect the three-phase windings of the brake motor. The control circuit is used to control the power circuit to output a brake motor drive current to the three-phase windings of the brake motor, and the brake motor drive current is used to control the brake motor to drive the brake caliper to brake the brake disc.

15. An electric vehicle, characterized in that, The electric vehicle includes the electromechanical braking system and the drive system according to any one of claims 1-10. The drive system includes a drive motor and a motor controller. During the braking process of the electric vehicle, the electromechanical braking system is used to output a driving braking force, and the drive motor outputs a negative torque as the wheels of the electric vehicle rotate to provide a braking force for the electric vehicle.

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