Decoupling type brake-by-wire redundancy control method, device and system

Abstract

The invention relates to the technical field of brake-by-wire, and discloses a decoupling brake-by-wire redundancy control method, device and system, and the method comprises the steps: obtaining a brake pedal stroke signal, calculating the target pressure of an auxiliary main cylinder, and outputting a drive instruction to a motor; an actual pressure signal fed back by the auxiliary main cylinder pressure sensor is monitored in real time, and whether the actual pressure signal is normal or not is judged; if yes, pressure closed-loop control is conducted according to the target pressure and the actual pressure; if not, a motor stroke signal is monitored in real time, and a first estimated value of the auxiliary main cylinder pressure is obtained by combining the PV curve; a motor current signal is monitored in real time, and a second estimated value of the auxiliary main cylinder pressure is obtained by combining the mapping relation between the motor output torque and the auxiliary main cylinder pressure; taking a weighted fusion value of one or two of the two estimated values as the estimated pressure of the auxiliary main cylinder; and performing pressure closed-loop control according to the target pressure and the estimated pressure. The effectiveness of pressure closed-loop control under the working condition that the auxiliary main cylinder pressure sensor loses efficacy is ensured.

Description

Technical Field

[0001] This invention belongs to the field of brake-by-wire technology, and particularly relates to a decoupled brake-by-wire redundancy control method, device and system. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Traditional vacuum boosters rely on the vacuum level in the engine intake manifold for assistance, which has significant drawbacks in autonomous driving and energy recovery. Therefore, they are gradually being replaced by decoupled brake-by-wire controllers, with products based on decoupled brake-by-wire controllers (such as One-Box / Two-Box architectures) being particularly typical. This system first captures the driver's braking intention through a pedal travel sensor. The electronic control unit (ECU) calculates the driver's target pressure based on multiple parameters such as pedal travel, vehicle speed, and load. Then, it controls the motor to drive the transmission mechanism, pushing the piston in the secondary master cylinder to compress the brake fluid and build up hydraulic pressure. This hydraulic pressure is transmitted through pipelines to the wheel brake cylinders, pushing the brake pads to clamp the brake discs and generate braking force. In this system, the secondary master cylinder pressure sensor is a key feedback element for achieving closed-loop pressure control. It collects the actual hydraulic pressure in the secondary master cylinder in real time and feeds it back to the ECU. The ECU dynamically adjusts the motor's output torque by comparing the deviation between the target pressure and the actual pressure, ensuring that the braking force matches the driver's intention.

[0004] However, this sensor is at risk of failure or malfunction in actual working conditions. In existing technical solutions, when the ECU detects that the secondary master cylinder pressure sensor has failed, it usually switches to backup braking state to avoid loss of braking force. In this state, the system relies only on mechanical backup mechanisms (such as spring accumulators or manual pushing of backup pistons) to establish basic hydraulic pressure, which results in the braking execution system lacking logical judgment signals, leading to driving safety problems such as excessive wheel cylinder pressure or insufficient braking force. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a decoupled brake-by-wire redundancy control method, device and system to ensure the effectiveness of pressure closed-loop control even when the auxiliary master cylinder pressure sensor fails.

[0006] To achieve the above objectives, a first aspect of the present invention provides a decoupled brake-by-wire redundancy control method, applied to a brake-by-wire controller, comprising the following steps: Acquire the brake pedal travel signal, calculate the target pressure of the secondary master cylinder, and output drive commands to the motor; Real-time monitoring of the actual pressure signal fed back by the secondary master cylinder pressure sensor to determine whether the actual pressure signal is normal; If so, pressure closed-loop control is performed based on the deviation between the target pressure and the actual pressure; If not, monitor the motor stroke signal in real time, determine the stroke of the secondary master cylinder based on the motor stroke, and obtain the first estimated value of the secondary master cylinder pressure by combining it with the PV curve; monitor the motor current signal in real time, determine the motor output torque based on the motor current, and obtain the second estimated value of the secondary master cylinder pressure by combining the mapping relationship between the motor output torque and the secondary master cylinder pressure; use the first estimated value and the second estimated value as the estimated pressure of the secondary master cylinder, or perform weighted fusion of the first estimated value and the second estimated value to obtain the estimated pressure of the secondary master cylinder; perform pressure closed-loop control based on the deviation between the target pressure and the estimated pressure.

[0007] In some embodiments, determining whether the actual pressure signal is normal includes performing integrity checks, rationality checks, and stability checks on the actual pressure signal.

[0008] In some embodiments, the weighted fusion of the first estimate and the second estimate to obtain the sub-master cylinder estimated pressure includes: acquiring real-time pedal travel, vehicle speed, and energy recovery status; determining the pressure build-up rate based on the pedal travel change rate; determining the vehicle driving status based on the vehicle speed and energy recovery status; determining the current pressure build-up stage based on the change rate of the first estimate / second estimate; obtaining a multi-dimensional operating condition combination; matching the weights of the first estimate and the second estimate according to a preset weight allocation table; and weighted fusion of the first estimate and the second estimate to obtain the sub-master cylinder estimated pressure.

[0009] In some embodiments, during the pressure closed-loop control process based on the deviation between the target pressure and the estimated pressure, the brake pedal travel signal, current vehicle status and road environment data are also acquired in real time, and the expected deceleration of the vehicle is estimated; the actual deceleration of the vehicle is monitored in real time, and when the actual deceleration is less than the expected deceleration, braking force compensation is performed through mechanical backup braking and / or EPB dynamic braking.

[0010] In some embodiments, when the actual deceleration is less than the expected deceleration and the deviation value is lower than the set collaborative triggering threshold, the required braking force is estimated based on the deviation value and the vehicle load; braking force compensation is performed through mechanical backup braking, and the pressure build-up rate is determined based on the magnitude of the deviation value, so that compensation is completed within a set time.

[0011] In some embodiments, when the actual deceleration is less than the expected deceleration and the deviation exceeds a set collaborative triggering threshold, the required braking force is estimated based on the deviation and vehicle load; braking force is distributed, and the required braking force is provided through EPB braking according to a set ratio, while mechanical backup braking is simultaneously activated to build pressure into the brake line at a preset pressure build-up rate; when the deviation is less than a set first deviation threshold, the required braking force is recalculated, and most of the required braking force is provided through mechanical backup braking, while the remaining required braking force is handled by EPB braking; when the deviation is less than a set second deviation threshold, the EPB clamping force is gradually unloaded first, and then the mechanical backup braking pressure is gradually reduced.

[0012] In some embodiments, if the secondary master cylinder pressure does not reach the expected level within a set time after the mechanical backup brake is activated, the full braking force is provided by the EPB brake.

[0013] A second aspect of the present invention provides a decoupled brake-by-wire redundancy control device, comprising: The driver intent acquisition module is configured to: acquire the brake pedal travel signal, calculate the target pressure of the secondary master cylinder, and output drive commands to the motor; The sensor failure judgment module is configured to: monitor the actual pressure signal fed back by the auxiliary master cylinder pressure sensor in real time, and determine whether the actual pressure signal is normal; if yes, enter the normal closed-loop control module; if no, enter the redundant closed-loop control module. The normal closed-loop control module is configured to perform pressure closed-loop control based on the deviation between the target pressure and the actual pressure. The redundant closed-loop control module is configured to: monitor the motor stroke signal in real time, determine the stroke of the secondary master cylinder based on the motor stroke, and obtain a first estimate of the secondary master cylinder pressure by combining the PV curve; monitor the motor current signal in real time, determine the motor output torque based on the motor current, and obtain a second estimate of the secondary master cylinder pressure by combining the mapping relationship between the motor output torque and the secondary master cylinder pressure; use the first estimate and the second estimate as the estimated pressure of the secondary master cylinder, or perform a weighted fusion of the first estimate and the second estimate to obtain the estimated pressure of the secondary master cylinder; and perform pressure closed-loop control based on the deviation between the target pressure and the estimated pressure.

[0014] A third aspect of the present invention provides a brake-by-wire controller, including a processor and a memory, wherein the memory stores computer instructions that, when executed by the processor, cause the brake-by-wire controller to perform the method described thereon.

[0015] A fourth aspect of the present invention provides a decoupled brake-by-wire system, including a brake-by-wire controller, a signal acquisition module, and an execution unit, wherein the brake-by-wire controller is configured to perform the method described herein.

[0016] In the braking control process of a decoupled brake-by-wire system, when the auxiliary master cylinder pressure sensor signal fails abnormally, the system can obtain the estimated pressure of the auxiliary master cylinder through the generation of the motor stroke and PV curve, and / or the mapping relationship between motor current and torque pressure. This effectively avoids the system degradation or insufficient braking force caused by the failure of the auxiliary master cylinder pressure sensor, ensures the effectiveness of pressure closed-loop control under sensor failure conditions, and improves the level of driving safety. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram illustrating the working principle of the decoupled brake-by-wire system in an embodiment of the present invention. Figure 2 This is a flowchart of the decoupled linear braking redundancy control method in an embodiment of the present invention; Figure 3 This is a schematic diagram of the signal flow of the redundancy control strategy in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the principle of sub-master cylinder pressure estimation in an embodiment of the present invention; Figure 5 This is a schematic diagram of the signal flow of the secondary failure monitoring strategy in an embodiment of the present invention; Figure 6 This is a schematic diagram of the program module of the decoupled linear braking redundancy control device in an embodiment of the present invention. Detailed Implementation

[0019] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0020] In the description of the embodiments of this application, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on".

[0021] As described in the background section, during brake-by-wire operation, the brake-by-wire controller first receives the pedal travel signal transmitted by the pedal travel acquisition module. Using this signal, it calculates the target pressure matching the driver's braking intention. Subsequently, the controller sends a command to the execution unit, which drives the secondary master cylinder to move and establish brake hydraulic pressure. Simultaneously, relying on the pressure signal collected in real-time by the secondary master cylinder pressure sensor, a pressure closed-loop control is formed to ensure accurate braking force output. However, in existing technology, if the secondary master cylinder pressure sensor fails, the controller will be unable to obtain a valid pressure feedback signal. In this case, the brake-by-wire system will trigger a degradation mechanism, switching to a backup braking state. However, the braking force output capability in the backup braking state is limited, which can easily lead to insufficient braking force and pose a safety hazard. To address this issue, the present invention designs a redundant control system for the stroke sensor signal of the brake-by-wire booster. When the secondary master cylinder pressure sensor fails, the system activates the secondary master cylinder pressure estimation module. This module combines the preset PV curve (pressure-volume relationship curve) of the braking system with synchronously collected signals such as motor stroke and motor current. Through multi-parameter fusion, it calculates the estimated secondary master cylinder pressure. Subsequently, the estimated pressure signal is transmitted to the execution unit and compared with the target braking pressure to reconstruct the pressure closed-loop control, ensuring the stability and accuracy of braking force, thereby avoiding the driving risks caused by the degradation of the brake-by-wire system.

[0022] Figure 1 A schematic diagram 100 of a decoupled brake-by-wire system according to one or more embodiments of the present invention is shown. The decoupled brake-by-wire system includes a brake-by-wire controller 101, a signal acquisition module 102, and an execution unit 103. The signal acquisition module 102 includes a pedal travel sensor and a secondary master cylinder pressure sensor; the execution unit 103 includes a motor and a secondary master cylinder. The brake-by-wire controller 101 acquires relevant signals required for braking control from the vehicle control system, on-board sensors, and various automatic control submodules, and identifies the driver's braking intention by analyzing these signals in real time. Specifically, the pedal travel sensor in the signal acquisition module 102 identifies the depth of the brake pedal depressed and the braking state; wheel speed signals are acquired through wheel speed sensors to determine the rotation of the four wheels; longitudinal deceleration signals are acquired through a vehicle longitudinal deceleration sensor; secondary master cylinder pressure signals are acquired through a secondary master cylinder pressure sensor; and the motor operating current is acquired through a motor current signal. In addition, information such as vehicle speed, gear position, and actual motor torque can also be acquired. The acquisition of the above signals is achieved through the vehicle's internal CAN bus. During the online braking process, the brake-by-wire controller 101 analyzes the received pedal travel signal, calculates the desired deceleration of the vehicle and the corresponding target pressure of the secondary master cylinder, and sends a pressure control request to the motor in the execution unit 103 to drive the secondary master cylinder to complete the establishment and adjustment of the brake hydraulic pressure.

[0023] Figure 2A flowchart of an example method 200 for a brake-by-wire system, applied to a brake-by-wire controller 101, is shown, according to one or more embodiments of the present invention.

[0024] The method 200 is described in detail below. Specifically, the method 200 includes the following steps: S201. Obtain the brake pedal travel signal, calculate the target pressure of the secondary master cylinder, and output a drive command to the motor. S202. During the movement of the auxiliary master cylinder controlled by the motor, the actual pressure signal fed back by the auxiliary master cylinder pressure sensor is monitored in real time to determine whether the actual pressure signal is normal; if yes, proceed to step S203; if no, proceed to step S204. S203. Perform closed-loop pressure control based on the deviation between the target pressure and the actual pressure. S204. Monitor the motor stroke signal in real time, determine the stroke of the auxiliary master cylinder based on the motor stroke, and obtain the first estimated value of the auxiliary master cylinder pressure by combining the PV curve; monitor the motor current signal in real time, determine the motor output torque based on the motor current, and obtain the second estimated value of the auxiliary master cylinder pressure by combining the mapping relationship between the motor output torque and the auxiliary master cylinder pressure; use the first estimated value and the second estimated value as the estimated pressure of the auxiliary master cylinder, or perform weighted fusion of the first estimated value and the second estimated value to obtain the estimated pressure of the auxiliary master cylinder; perform pressure closed-loop control based on the deviation between the target pressure and the estimated pressure.

[0025] In the braking control process of a decoupled brake-by-wire system, when the auxiliary master cylinder pressure sensor signal fails abnormally, the system can obtain the estimated pressure of the auxiliary master cylinder through the generation of motor stroke and PV curve, and / or the mapping relationship between motor current and torque pressure. This effectively avoids the system degradation or insufficient braking force caused by the failure of the auxiliary master cylinder pressure sensor, ensures the effectiveness of pressure closed-loop control under sensor failure conditions, and improves the fault tolerance and driving safety level of the system.

[0026] In step S201, the brake-by-wire controller first calculates the braking force based on the pedal travel signal, and obtains the secondary master cylinder hydraulic pressure based on the mapping relationship between the braking force and the secondary master cylinder hydraulic pressure. Based on the PV curve, the target pressure of the secondary master cylinder is determined according to the secondary master cylinder hydraulic pressure. A drive command is generated based on the target pressure of the secondary master cylinder and sent to the execution unit, causing the execution unit to drive the motor to control the movement of the secondary master cylinder and output the hydraulic pressure required by the braking system.

[0027] Among them, the PV curve, or pressure-volume relationship curve, is a pre-calibrated characteristic curve of the braking system that reflects the change in brake fluid volume in the secondary master cylinder and the corresponding change in hydraulic pressure (the horizontal axis represents the volume change and the vertical axis represents the pressure).

[0028] In step S202, during the process of the motor-driven auxiliary master cylinder moving and building pressure, the real hydraulic pressure signal of the brake fluid in the auxiliary master cylinder, collected in real time by the auxiliary master cylinder pressure sensor, is acquired. Simultaneously, the built-in signal diagnostic module is activated to perform real-time verification of the signal according to preset judgment criteria: if the signal meets the requirements for integrity, rationality, and stability, the signal is determined to be normal, and the process jumps to step S203 to execute conventional closed-loop control; if the signal triggers any abnormal judgment condition, the signal is determined to be abnormal, and the process jumps to step S204 to execute redundant control. Integrity verification includes checks such as whether the signal is continuously zero, continuously exceeds the range, or exceeds the normal fluctuation range; rationality verification includes checks such as whether the pressure change rate is abnormal, whether the pressure signal matches the motor stroke / current; and stability verification includes checks such as whether the signal fluctuation amplitude is too large within a short period.

[0029] In step S203, the pressure closed-loop control continuously compares the deviation between the target pressure and the actual pressure, and dynamically adjusts the control command to make the actual pressure approach and stabilize at the target pressure. Specifically: if the actual pressure is lower than the target pressure, the duty cycle of the motor drive command is increased to increase the motor speed and torque, pushing the auxiliary master cylinder piston to move further to increase the pressure; if the actual pressure is higher than the target pressure, the duty cycle of the motor drive command is decreased to reduce the motor output, or the motor is controlled to reverse slightly to retract the piston to reduce the pressure, until the deviation between the actual pressure and the target pressure is controlled within a certain range.

[0030] In step S204, the mapping relationship between the motor output torque and the sub-master cylinder pressure is a pre-calibrated model that reflects the correspondence between the motor output torque and the hydraulic pressure in the sub-master cylinder, and is determined by the mechanical structural parameters of the sub-master cylinder (such as piston area and transmission efficiency).

[0031] When the secondary master cylinder pressure sensor fails, this embodiment provides two pressure estimation methods, which can be redundant or weighted and fused. The first method uses the motor stroke signal to reflect the distance the motor drives the secondary master cylinder piston to move, and the pressure is estimated based on the PV curve. The second method uses the fixed mapping relationship between the motor current signal and the motor output torque, and the pressure is estimated based on this mapping. Each of these two pressure estimation methods has its advantages, and the final estimated pressure can be calculated by arbitrating the results and using weighted filtering.

[0032] In some embodiments, the weight ratio of the two estimates is dynamically adjusted based on their accuracy under different operating conditions. Generally, under conditions such as low-speed pressure build-up, pressure holding, and low-speed driving, the brake fluid volume changes gradually, the system load is stable, and the PV curve (pressure-volume relationship) has high accuracy. However, motor torque estimation is easily affected by mechanical friction and current ripple interference, so the weight of the PV curve (first estimate) should be increased first. Under conditions such as high-speed pressure build-up, emergency braking, and energy recovery coordination, the pressure change rate is fast, and the load fluctuates greatly. The motor torque estimation (second estimate) can respond to load changes in real time through the current signal, and has high accuracy. However, the PV curve is prone to estimation deviations due to volume measurement delays, so the weight of the motor torque estimation should be increased first.

[0033] Based on the above principles, a weight allocation table is preset for different operating conditions. The operating conditions are determined by three dimensions: pressure build-up rate, vehicle driving state, and pressure build-up stage. For example, the pressure build-up rate includes low speed, medium speed, and high speed; the vehicle driving state includes low speed, medium-high speed, high speed, and energy recovery coordination; and the pressure build-up stage includes initial pressure build-up, pressure regulation, and mid-pressure build-up. Different states in these three dimensions can determine multiple operating condition combinations. Through bench testing and real-vehicle calibration, the accuracy of the first and second estimated values ​​under different operating condition combinations can be determined. Based on this, weights are set for the first and second estimated values, resulting in a weight allocation table. This table includes the judgment conditions for multi-dimensional operating conditions, as well as the weights of the first and second estimated values ​​corresponding to the multi-dimensional operating condition combinations. For example, real-time pedal travel, vehicle speed, and energy recovery status are acquired. The pressure build-up rate is determined based on the pedal travel change rate. The vehicle driving state is determined based on the vehicle speed and energy recovery status. The current pressure build-up stage is determined based on the change rate of the first and second estimated values, resulting in a multi-dimensional operating condition combination. The weights of the first and second estimated values ​​are matched according to the preset weight allocation table. For example, the multi-dimensional working condition combination matching a pressure build-up rate of 0.1 MPa / ms, a vehicle speed of 60 km / h, and a pressure of 5 MPa is: medium-speed pressure build-up, medium-high speed driving, and pressure adjustment stage. In the weight allocation table, the weight of the first estimate and the second estimate is 50% each.

[0034] It is understandable that in the above steps S203 and S204, after obtaining signals such as pressure and current, filtering and noise reduction processing is also performed.

[0035] The aforementioned pressure estimation method relies on the PV curve or the mapping relationship between motor torque and sub-master cylinder pressure. During long-term use, brake fluid aging and pipeline elastic deformation can cause deviations in the PV curve characteristics, and brake fluid leakage can also cause the estimated value to deviate from the actual value. Wear of the motor or transmission mechanism can disrupt the current-torque-pressure mapping relationship, all of which affect the accuracy of pressure estimation. Furthermore, even if the pressure estimation is normal, abnormal transmission in the transmission mechanism can affect the reliable output of braking force. That is, the aforementioned redundant braking method still has the possibility of secondary failure. In some embodiments, secondary failure monitoring is also performed when performing closed-loop control based on the target pressure and estimated pressure values, such as... Figure 3 As shown, the brake-by-wire control module performs safety checks based on pedal travel and deceleration. When the actual deceleration does not meet the driver's needs, it enters mechanical backup braking + EPB backup braking to prevent the system from undergoing secondary degradation and causing a lack of braking force.

[0036] Specifically, in step S204, during the closed-loop control process based on the deviation between the target pressure and the estimated pressure, the desired deceleration of the vehicle is estimated in real time based on the brake pedal travel signal; the actual deceleration of the vehicle is monitored in real time, and when the actual deceleration is less than the expected deceleration, braking force compensation is performed through mechanical backup braking and / or EPB dynamic braking.

[0037] In step S201, a pre-defined mapping relationship between pedal travel and deceleration can be established, and the desired deceleration of the vehicle can be determined based on the pedal travel. Alternatively, the desired deceleration can also be estimated based on the driver's historical braking data, using pedal travel signals, current vehicle status, and road environment data. For example, vehicle status includes vehicle load and vehicle driving state, which includes vehicle speed and straight / turning status; road environment data includes road slope and road type (dry asphalt road, wet asphalt road, icy / snowy road, etc.). Based on historical braking data, pedal travel, travel change rate, vehicle load, vehicle speed, road slope, road type, and actual deceleration are obtained to construct a training dataset. A deceleration estimation model is trained based on a machine learning model. The desired deceleration is estimated using the pedal travel signal, current vehicle status, and road environment data, according to the deceleration estimation model.

[0038] In step S204, when the actual deceleration is less than the expected deceleration, when braking force compensation is performed through mechanical backup braking and EPB dynamic braking, mechanical backup braking has the disadvantage of pressure build-up lag, but has good stability, while EPB directly clamps through electronic calipers and has a fast response speed. Therefore, when performing braking force compensation, EPB braking is executed first, and then dynamically transitions to mechanical backup braking.

[0039] For example, when the actual deceleration is less than the expected deceleration and the deviation is lower than the set collaborative triggering threshold, the required braking force is estimated based on the deviation and vehicle load; braking force compensation is performed through mechanical backup braking, and the pressure build-up rate is determined based on the magnitude of the deviation, so that compensation is completed within a set time. When the actual deceleration is less than the expected deceleration and the deviation exceeds the set collaborative triggering threshold, the required braking force is estimated based on the deviation and vehicle load; braking force distribution is performed, and the required braking force is provided through EPB braking according to a set ratio (e.g., 50%), while mechanical backup braking is simultaneously activated to build pressure into the brake line at a preset pressure build-up rate; when the deviation between the actual deceleration and the expected deceleration is less than the set first deviation threshold, the required braking force is recalculated, and most of the required braking force (e.g., 80%) is provided through mechanical backup braking, while the remaining required braking force is handled by EPB braking; when the deviation between the actual deceleration and the expected deceleration is less than the set second deviation threshold, the EPB clamping force is gradually unloaded first, and then the mechanical backup braking pressure is gradually reduced. Among them, the first deviation threshold is greater than the second deviation threshold. When the deviation value is less than the set second deviation threshold, it is considered that the braking force compensation has been completed. The coordinated trigger threshold is, for example, 0.6 m / s², the first deviation threshold is, for example, 0.4 m / s², and the second deviation threshold is, for example, 0.2 m / s².

[0040] If the aforementioned faults, such as brake fluid leakage, exist, the braking effect of mechanical pressure build-up will be affected. Therefore, if the pressure does not reach the expected level within the set time (e.g., 100ms) after the mechanical backup brake is activated, the EPB brake will provide all braking force. It is understood that the maximum clamping force of the EPB cannot exceed its thermal stability limit.

[0041] In the aforementioned braking force compensation strategy, when the deviation between the actual deceleration and the expected deceleration is lower than the collaborative triggering threshold, compensation is provided solely through the mechanical backup brake. This leverages the linear stability of its hydraulic control to correct minor to moderate deceleration deficiencies, avoiding hardware wear caused by frequent EPB intervention and ensuring consistency between braking force and driver needs. When the deviation exceeds the collaborative triggering threshold, the collaborative control of the EPB and mechanical backup brake is activated. The rapid response characteristic of the EPB's electronic caliper direct clamping is utilized to prioritize braking force, compensating for the pressure build-up lag of the mechanical backup brake. Gradually, the mechanical backup brake takes over as the primary braking force, leveraging its linear advantage. Finally, braking force compensation ends by first unloading the EPB and then reducing the mechanical pressure, preventing sudden changes in braking force that could cause body impact and discomfort, thus balancing braking control accuracy, system stability, and passenger experience.

[0042] Based on the above method, one or more embodiments of the present invention also provide a decoupled brake-by-wire redundancy control device 600, including: a driver intent acquisition module 601, configured to: acquire brake pedal travel signal, calculate the target pressure of the secondary master cylinder, and output a drive command to the motor; a sensor failure judgment module 602, configured to: monitor the actual pressure signal fed back by the secondary master cylinder pressure sensor in real time, and determine whether the actual pressure signal is normal; if so, enter the normal closed-loop control module; if not, enter the redundancy closed-loop control module; a normal closed-loop control module 603, configured to: determine the relationship between the target pressure and the actual pressure... The deviation is used for pressure closed-loop control; the redundant closed-loop control module 604 is configured to: monitor the motor stroke signal in real time, determine the stroke of the auxiliary master cylinder based on the motor stroke, and obtain a first estimated value of the auxiliary master cylinder pressure by combining the PV curve; monitor the motor current signal in real time, determine the motor output torque based on the motor current, and obtain a second estimated value of the auxiliary master cylinder pressure by combining the mapping relationship between the motor output torque and the auxiliary master cylinder pressure; use the first estimated value and the second estimated value as the estimated pressure of the auxiliary master cylinder, or perform weighted fusion of the first estimated value and the second estimated value to obtain the estimated pressure of the auxiliary master cylinder; and perform pressure closed-loop control based on the deviation between the target pressure and the estimated pressure.

[0043] Furthermore, one or more embodiments of the present invention also provide a brake-by-wire controller, which can be used to implement the decoupled brake-by-wire redundancy control method in the above embodiments. The brake-by-wire controller includes one or more processors, one or more memories coupled to the processors, and a communication module coupled to the processors.

[0044] The memory may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, at least one of the following: read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, hard disk, compact disc (CD), digital video disc (DVD), or other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, at least one of the following: random access memory (RAM), or other volatile memories that do not persist during the power-off period. The computer program may be stored in the ROM. When the processor executes the computer program, it implements the decoupled linear braking redundancy control method described above.

[0045] In some embodiments, the program may be tangibly contained in a computer-readable medium, which may include a device (such as in memory) or other storage device accessible by the device. The program may be loaded from the computer-readable medium into RAM for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, whereby the computer-readable storage medium stores a computer program that, when executed by a processor, implements the decoupled linear braking redundancy control method described above.

[0046] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a server or terminal, they generate, in whole or in part, the processes or functions described in the embodiments of this application. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic cable, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to the server or terminal, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, and magnetic tape), an optical medium (e.g., digital video disk (DVD), etc.), or a semiconductor medium (e.g., solid-state drive).

[0047] Furthermore, although the operations are described in a specific order, this should be understood as requiring that such operations be performed in the specific order shown or in sequential order, or requiring that all illustrated operations be performed to achieve the desired result. In certain environments, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this application. Certain features described in the context of individual embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations.

[0048] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

Claims

1. A decoupled linear braking redundancy control method, characterized in that, Applied to brake-by-wire controllers, the following steps are included: Acquire the brake pedal travel signal, calculate the target pressure of the secondary master cylinder, and output drive commands to the motor; Real-time monitoring of the actual pressure signal fed back by the secondary master cylinder pressure sensor to determine whether the actual pressure signal is normal; If so, pressure closed-loop control is performed based on the deviation between the target pressure and the actual pressure; If not, monitor the motor stroke signal in real time, determine the stroke of the secondary master cylinder based on the motor stroke, and obtain the first estimated value of the secondary master cylinder pressure by combining it with the PV curve; monitor the motor current signal in real time, determine the motor output torque based on the motor current, and obtain the second estimated value of the secondary master cylinder pressure by combining the mapping relationship between the motor output torque and the secondary master cylinder pressure; use the first estimated value and the second estimated value as the estimated pressure of the secondary master cylinder, or perform weighted fusion of the first estimated value and the second estimated value to obtain the estimated pressure of the secondary master cylinder; perform pressure closed-loop control based on the deviation between the target pressure and the estimated pressure.

2. The decoupled linear braking redundancy control method as described in claim 1, characterized in that, Determining whether the actual pressure signal is normal includes verifying the integrity, rationality, and stability of the actual pressure signal.

3. The decoupled linear braking redundancy control method as described in claim 1, characterized in that, The process of weightedly fusing the first and second estimates to obtain the sub-master cylinder estimated pressure includes: acquiring real-time pedal travel, vehicle speed, and energy recovery status; determining the pressure build-up rate based on the pedal travel change rate; determining the vehicle driving status based on vehicle speed and energy recovery status; determining the current pressure build-up stage based on the change rate of the first and second estimates; obtaining a multi-dimensional operating condition combination; matching the weights of the first and second estimates according to a preset weight allocation table; and weightedly fusing the first and second estimates to obtain the sub-master cylinder estimated pressure.

4. The decoupled linear braking redundancy control method as described in claim 1, characterized in that, During the pressure closed-loop control process based on the deviation between the target pressure and the estimated pressure, the brake pedal travel signal, current vehicle status and road environment data are also acquired in real time, and the expected deceleration of the whole vehicle is estimated; the actual deceleration of the vehicle is monitored in real time, and when the actual deceleration is less than the expected deceleration, braking force compensation is performed through mechanical backup braking and / or EPB dynamic braking.

5. The decoupled linear braking redundancy control method as described in claim 4, characterized in that, When the actual deceleration is less than the expected deceleration and the deviation is lower than the set collaborative trigger threshold, the required braking force is estimated based on the deviation and vehicle load; braking force compensation is performed through mechanical backup braking, and the pressure build-up rate is determined based on the magnitude of the deviation, so that compensation is completed within a set time.

6. The decoupled linear braking redundancy control method as described in claim 4, characterized in that, When the actual deceleration is less than the expected deceleration and the deviation exceeds the set collaborative trigger threshold, the required braking force is estimated based on the deviation and vehicle load; braking force distribution is performed, and the required braking force is provided through the EPB brake according to the set ratio, while the mechanical backup brake is activated simultaneously to build pressure into the brake line at a preset pressure build-up rate; when the deviation is less than the set first deviation threshold, the required braking force is recalculated, and most of the required braking force is provided through the mechanical backup brake, while the remaining required braking force is handled by the EPB brake; when the deviation is less than the set second deviation threshold, the EPB clamping force is gradually unloaded first, and then the mechanical backup brake pressure is gradually reduced.

7. The decoupled linear braking redundancy control method as described in claim 5 or 6, characterized in that, If the secondary master cylinder pressure does not reach the expected level within the set time after the mechanical backup brake is activated, the full braking force will be provided through the EPB brake.

8. A decoupled linear braking redundancy control device, characterized in that, include: The driver intent acquisition module is configured to: acquire the brake pedal travel signal, calculate the target pressure of the secondary master cylinder, and output drive commands to the motor; The sensor failure detection module is configured to: monitor the actual pressure signal fed back by the auxiliary master cylinder pressure sensor in real time and determine whether the actual pressure signal is normal; If yes, enter the normal closed-loop control module; otherwise, enter the redundant closed-loop control module. The normal closed-loop control module is configured to perform pressure closed-loop control based on the deviation between the target pressure and the actual pressure. The redundant closed-loop control module is configured to: monitor the motor stroke signal in real time, determine the stroke of the auxiliary master cylinder based on the motor stroke, and obtain the first estimate of the auxiliary master cylinder pressure by combining the PV curve; Real-time monitoring of motor current signal; determination of motor output torque based on motor current; and obtaining a second estimated value of sub-master cylinder pressure by combining the mapping relationship between motor output torque and sub-master cylinder pressure. The first and second estimates are used as the estimated pressure of the secondary master cylinder, or the first and second estimates are weighted and fused to obtain the estimated pressure of the secondary master cylinder; pressure closed-loop control is performed based on the deviation between the target pressure and the estimated pressure.

9. A brake-by-wire controller, comprising a processor and a memory, wherein the memory stores computer instructions, characterized in that, When the computer instructions are executed by the processor, the brake-by-wire controller performs the method of any one of claims 1 to 7.

10. A decoupled brake-by-wire system, comprising a brake-by-wire controller, a signal acquisition module, and an execution unit, characterized in that, The brake-by-wire controller is configured to perform the method of any one of claims 1 to 7.

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