Redundancy control method and system for anti-lock braking system under EMB system and vehicle

Abstract

The invention relates to the technical field of vehicle control, and provides a redundancy control method and system for an anti-lock braking system under an EMB system and a vehicle. The redundancy control method comprises the steps that in response to a clamping force request transmitted by a central domain controller, motor control is conducted; the method comprises the following steps: in response to a central domain controller fault signal, judging a vehicle braking working condition, determining an initial clamping force request according to the vehicle braking working condition, triggering braking, adjusting the clamping force request according to a vehicle state, calculating a slip rate based on a vehicle wheel speed, comparing the slip rate with a slip rate target range, and adjusting the clamping force request according to a comparison result. Performing motor control; wherein the slip rate target range is adjusted according to the road surface condition obtained by recognizing the image of the road surface in front of the vehicle. The ABS function has redundancy control, rapid braking is guaranteed, meanwhile, longitudinal braking force and lateral stability are better balanced, and higher guarantee is provided for driving safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle control, and in particular relates to a redundant control method, system and vehicle of an anti-lock braking system under an EMB system. Background Art

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

[0003] The Anti-lock Brake System (ABS) is a very important basic function of the braking system and is closely related to driving safety. Therefore, redundant control of this function can greatly improve the driver's driving safety.

[0004] In the current models equipped with hydraulic brake systems, the ABS control module is integrated into the ECU of the ESC / OneBOX controller, without redundant control. Only the TwoBOX solution can be equipped with ABS redundant control. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a redundant control method, system and vehicle of an anti-lock braking system under an EMB system, which fully utilizes the advantages of multiple controllers of the EMB system. When the central domain controller is abnormal, the ABS function is controlled by the wheel-end controller, so that the ABS function has redundant control, and the slip rate target range is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle, so as to ensure rapid braking while better balancing the longitudinal braking force and lateral stability, providing higher protection for driving safety.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a redundant control method for an anti-lock braking system under an EMB system, which is applied to a wheel-end controller and includes:

[0008] controlling the motor in response to a clamping force request transmitted from the central domain controller;

[0009] In response to a fault signal from a central domain controller, a vehicle braking condition is determined, an initial clamping force request is determined according to the vehicle braking condition, after braking is initiated, the clamping force request is adjusted according to the vehicle state, a slip ratio is calculated based on the vehicle wheel speed, the slip ratio is compared with a slip ratio target range, the clamping force request is adjusted according to the comparison result, and a motor control is performed;

[0010] The target range of the slip ratio is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle.

[0011] Furthermore, the vehicle state includes vehicle speed, vehicle load, lateral acceleration, steering wheel angle, lateral acceleration and yaw rate.

[0012] Furthermore, when the central domain controller is working normally, it determines the vehicle braking condition, determines the initial clamping force request based on the vehicle braking condition, and after braking is triggered, adjusts the clamping force request based on the vehicle state, calculates the slip rate based on the vehicle wheel speed, compares the slip rate with the slip rate target range, adjusts the clamping force request based on the comparison result, and sends the clamping force request to the wheel-end controller.

[0013] Furthermore, the motor control step includes: calculating the clamping force based on the clamping force request, and obtaining the motor torque request according to the clamping force calculation result; estimating the torque that the motor can actually output; and driving the motor to apply clamping force to the wheel according to the motor torque request and the estimation result.

[0014] A second aspect of the present invention provides a redundant control system for an anti-lock braking system under an EMB system, which is configured in a wheel-end controller and includes:

[0015] A basic control module, which is configured to: perform motor control in response to a clamping force request transmitted from a central domain controller;

[0016] The redundant control module is configured to: in response to a central domain controller fault signal, determine a vehicle braking condition, determine an initial clamping force request according to the vehicle braking condition, adjust the clamping force request according to the vehicle state after initiating braking, calculate a slip ratio based on a vehicle wheel speed, compare the slip ratio with a slip ratio target range, adjust the clamping force request according to the comparison result, and perform motor control;

[0017] The target range of the slip ratio is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle.

[0018] Furthermore, the vehicle state includes vehicle speed, vehicle load, lateral acceleration, steering wheel angle, lateral acceleration and yaw rate.

[0019] Furthermore, when the central domain controller is working normally, it determines the vehicle braking condition, determines the initial clamping force request based on the vehicle braking condition, and after braking is triggered, adjusts the clamping force request based on the vehicle state, calculates the slip rate based on the vehicle wheel speed, compares the slip rate with the slip rate target range, adjusts the clamping force request based on the comparison result, and sends the clamping force request to the wheel-end controller.

[0020] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the redundant control method of an anti-lock braking system in an EMB system as described above.

[0021] A fourth aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in the redundant control method of the anti-lock braking system under the EMB system as described above are implemented.

[0022] The fifth aspect of the present invention provides a vehicle, utilizing the redundant control method of the anti-lock braking system under the EMB system as described in the first aspect; or, including the redundant control system of the anti-lock braking system under the EMB system as described in the second aspect; or, including a computer-readable storage medium as described in the third aspect; or, including a computer device as described in the fourth aspect.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention makes full use of the advantages of multiple controllers of the EMB system. When the central domain controller is abnormal, the ABS function is controlled by the wheel-end controller, so that the ABS function has redundant control, and the target range of the slip rate is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle, so as to ensure rapid braking while better balancing the longitudinal braking force and lateral stability, providing higher protection for driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 The flowchart of the redundant control method of the anti-lock braking system in the EMB system according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0027] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0028] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0029] Embodiment 1

[0030] This embodiment provides a redundant control method for an anti-lock braking system in an EMB system.

[0031] In the emerging EMB brake system (Electromechanical Braking System), the presence of a central (Vehicle Motion) domain controller ECU and four independent wheel-end ECUs provides standard feasibility for redundant control of the ABS function.

[0032] The redundant control method of the anti-lock braking system under the EMB system provided in this embodiment places the main control of the ABS function in the central domain controller ECU in the vehicle model equipped with EMB. When the central domain controller ECU is abnormal, the ABS function is controlled by four independent wheel-end ECUs, making full use of the advantages of multiple ECUs of the EMB system and the relationship between the upper and lower ECUs, so that the ABS function has redundant control, providing higher protection for driving safety.

[0033] For cars equipped with EMB, the central domain controller and the front EMB controller ECU (i.e., wheel-end ECU) can calculate the reference vehicle speed, vehicle status, and slip rate by collecting information such as wheel speed, lateral acceleration, longitudinal acceleration, yaw angular velocity, and steering wheel angle provided by sensors.

[0034] When the central domain controller is working normally, the ABS function is controlled by the central domain controller: when the vehicle slip rate reaches the threshold value, the ABS is activated, and the four EMB calipers increase or decrease the pressure according to the clamping force request of the central domain controller to ensure that the wheels are not locked.

[0035] When the central domain controller is abnormal, the ABS function enters the redundant backup state and is controlled by the front EMB ECU: when the vehicle slip rate reaches the threshold value, the ABS is activated, and the front EMB ECU sends a clamping force request to control the increase or decrease of the pressure on the four EMB calipers to ensure that the wheels are not locked.

[0036] The redundancy control method of the anti-lock braking system under the EMB system provided in this embodiment is as follows: Figure 1 As shown, the following steps are included:

[0037] Step 1: External sensors are responsible for collecting key data during vehicle driving and transmitting it to the central domain controller and wheel-end controller.

[0038] Key data include brake pedal pressure, wheel speed, lateral acceleration, lateral acceleration, yaw angular velocity, steering wheel angle, vehicle speed, vehicle load, etc. These data reflect the vehicle's motion state and the driver's operating intention, and are the basic information for the entire braking control system to analyze and make decisions.

[0039] Step 2: When the central domain controller works normally, the ABS function is controlled by the central domain controller.

[0040] Step 201: Data processing.

[0041] (1) Reference speed calculation: The reference speed of the vehicle is calculated based on information such as wheel speed, providing a speed benchmark for subsequent braking control.

[0042] As an implementation manner, assuming that the wheel speeds of the four wheels are v1, v2, v3, and v4, respectively, and the tire radius is r, then the reference vehicle speed vref=r(v1+v2+v3+v4) / 4.

[0043] (2) Braking condition identification: Analyze various sensor data (brake pedal pressure, vehicle speed, or other characteristic signals) to determine whether the vehicle is in emergency braking, regular braking, or other braking conditions so that appropriate braking strategies can be adopted later.

[0044] For example, during emergency braking, a high brake pedal pressure, a rapid drop in vehicle speed or other characteristic signals of emergency braking are detected, and a large clamping force request is generated to achieve rapid deceleration.

[0045] (3) Slip ratio calculation: The wheel slip ratio is calculated based on information such as wheel speed and reference vehicle speed to determine whether the wheel is in a critical state of locking, thereby preventing wheel locking.

[0046] The slip rate s is used to describe the degree of wheel slip, and its definition formula is: When vref=0, s=0, where vref is the reference vehicle speed, r is the tire radius, and ω is the angular velocity of the wheel.

[0047] During braking, if the angular velocity of the wheel decreases (tending to lock), the slip rate will increase. During acceleration, if the wheel spins, the angular velocity increases, and the slip rate will change accordingly. The slip rate is calculated in real time by accurately measuring the wheel speed and the reference vehicle speed to determine the wheel slip state.

[0048] In order to obtain the best braking effect and stability, the clamping force request will be adjusted according to the slip rate target range. If the slip rate is too high, it means that the wheel may be about to lock, and the clamping force will be reduced; if the slip rate is too low, it means that the braking force is insufficient, and the clamping force will be increased.

[0049] (4) Determine the vehicle status.

[0050] In this embodiment, the vehicle state includes vehicle speed, vehicle load, lateral acceleration, steering wheel angle, lateral acceleration and yaw rate, etc.

[0051] Step 202: formulate a control strategy.

[0052] (1) The ABS control module makes an initial determination of the clamping force request.

[0053] Based on braking conditions: When the driver presses the brake pedal, the braking condition of the vehicle is preliminarily judged based on the brake pedal travel and the signal from the pressure sensor, and an initial clamping force request is generated based on the braking condition. For example, a large pedal travel and rapid pressure increase indicate emergency braking, and a large initial clamping force request is generated accordingly to quickly reduce the vehicle speed.

[0054] (2) Braking force distribution: Automatically adjust the braking force distribution of the front and rear wheels according to the vehicle status. Before or while the ABS control module is working, preliminary adjustments are made to the front and rear wheel clamping force requests to optimize the braking effect.

[0055] Vehicle speed is a critical factor. Generally speaking, the higher the vehicle speed, the greater the clamping force required to achieve the same deceleration.

[0056] The load of the vehicle also affects the clamping force request. If the vehicle is carrying heavier cargo or passengers, the clamping force will be increased accordingly to ensure adequate braking effect.

[0057] Information such as lateral acceleration, yaw rate, steering wheel angle and lateral acceleration will also be considered. When the driver turns the steering wheel, the vehicle enters the steering state. When the vehicle is turning, the outer wheels are subjected to greater centrifugal force. In order to maintain the vehicle's stable driving, the clamping force of each wheel needs to be reasonably adjusted according to the size and direction of the steering wheel angle, lateral acceleration, lateral acceleration and yaw rate. Generally speaking, the brake clamping force of the outer wheel may be appropriately increased to balance the centrifugal force and prevent the vehicle from skidding or losing control.

[0058] (3) ABS control module adjusts the clamping force:

[0059] Reduce clamping force: When it is detected that the wheel slip rate is higher than the target slip rate range (i.e., the vehicle dynamic control target) and is about to lock, the ECU will issue an instruction to reduce the brake clamping force request of the wheel, thereby controlling the hydraulic regulator (such as solenoid valve action) to reduce the hydraulic pressure in the brake wheel cylinder, thereby reducing the clamping force of the brake shoe or brake caliper on the wheel, allowing the wheel speed to rise and the slip rate to reduce.

[0060] Increase clamping force: If the wheel slip rate is lower than the target slip rate range, indicating that the braking force is insufficient, the ECU will increase the clamping force request for the wheel, increase the hydraulic pressure in the brake wheel cylinder, enhance the braking effect, and increase the wheel slip rate.

[0061] Maintain clamping force: When the wheel slip rate is within the target slip rate range, the ECU will maintain the current clamping force request to maintain a stable braking state.

[0062] During the entire braking process, the initial clamping force is adjusted according to the vehicle status, and the initial clamping force triggers braking; then the slip rate is calculated in real time, and the current clamping force is continuously adjusted according to the change in slip rate and the vehicle status, forming a dynamic closed-loop control process; through this continuous monitoring and adjustment, the wheel slip rate is always kept within the ideal range, ensuring that the vehicle can obtain maximum braking force while maintaining good handling and stability during braking.

[0063] In this embodiment, the target range of the slip ratio is adjusted according to the road conditions (dry, wet, or snowy), ensuring rapid braking while better balancing the longitudinal braking force and lateral stability. Specifically, the camera installed on the vehicle collects the road image in front of the vehicle; the image segmentation model is used to segment the target area of ​​the road image in front of the vehicle; for the target area, the convolutional neural network is used to extract features, and the road condition (dry, wet, or snowy) is obtained through the classifier; on dry roads, the target range of the slip ratio is adjusted to between 10% and 20%; on wet roads, the target range of the slip ratio is adjusted to between 12% and 22%; on snowy roads, the target range of the slip ratio is adjusted to between 15% and 25%.

[0064] Step 203, command output: After a series of calculations and decisions, the central domain controller sends a clamping force request to the left / right front and left / right rear EMB ECUs, indicating the amount of brake clamping force that needs to be applied to each wheel.

[0065] Step 3: The wheel-end controller performs motor control in response to the clamping force request transmitted from the central domain controller.

[0066] Step 4: The wheel-end controller responds to the fault signal of the central domain controller, executes the calculation process of steps 201-202, performs the same calculation processing and braking force distribution as the central controller, obtains the clamping force request, and then performs motor control.

[0067] In this embodiment, the steps of motor control include: based on the clamping force request, firstly calculate the clamping force to determine the actual clamping force value that needs to be applied, and then obtain the motor torque request according to the clamping force calculation result, that is, determine the motor torque required to drive the braking device; estimate the torque that the motor can actually output to ensure that the torque output by the motor meets the braking requirements; according to the motor torque request and the estimation result, accurately control the motor, and drive the braking device through the motor to apply the corresponding clamping force to the wheel to achieve the braking operation.

[0068] Embodiment 2

[0069] This embodiment provides a redundant control system for an anti-lock braking system under an EMB system, which is configured in a wheel-end controller and specifically includes:

[0070] A basic control module, which is configured to: perform motor control in response to a clamping force request transmitted from a central domain controller;

[0071] The redundant control module is configured to: in response to a central domain controller fault signal, determine a vehicle braking condition, determine an initial clamping force request according to the vehicle braking condition, adjust the clamping force request according to the vehicle state after initiating braking, calculate a slip ratio based on a vehicle wheel speed, compare the slip ratio with a slip ratio target range, adjust the clamping force request according to the comparison result, and perform motor control;

[0072] The target range of the slip ratio is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle.

[0073] Furthermore, the vehicle state includes vehicle speed, vehicle load, lateral acceleration, steering wheel angle, lateral acceleration and yaw rate.

[0074] Furthermore, when the central domain controller is working normally, it determines the vehicle braking condition, determines the initial clamping force request based on the vehicle braking condition, and after braking is triggered, adjusts the clamping force request based on the vehicle state, calculates the slip rate based on the vehicle wheel speed, compares the slip rate with the slip rate target range, adjusts the clamping force request based on the comparison result, and sends the clamping force request to the wheel-end controller.

[0075] It should be noted here that each module in this embodiment corresponds to each step in Example 1 one by one, and the specific implementation process is the same, which will not be repeated here.

[0076] Embodiment 3

[0077] This embodiment provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps in the redundant control method of the anti-lock braking system in the EMB system described in the first embodiment are implemented.

[0078] Embodiment 4

[0079] This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the redundant control method of the anti-lock braking system under the EMB system as described in the first embodiment above are implemented.

[0080] Embodiment 5

[0081] This embodiment provides a vehicle, utilizing the redundant control method of the anti-lock braking system under the EMB system as described in the above embodiment 1; or, including the redundant control system of the anti-lock braking system under the EMB system as described in the above embodiment 2; or, including a computer-readable storage medium as described in the above embodiment 3; or, including a computer device as described in the above embodiment 4.

[0082] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program code.

[0083] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0084] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0085] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0086] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. The redundant control method of the anti-lock braking system under the EMB system is characterized by: Applied to wheel end controllers, including: controlling the motor in response to a clamping force request transmitted from the central domain controller; In response to a fault signal from a central domain controller, a vehicle braking condition is determined, an initial clamping force request is determined according to the vehicle braking condition, after braking is initiated, the clamping force request is adjusted according to the vehicle state, a slip ratio is calculated based on the vehicle wheel speed, the slip ratio is compared with a slip ratio target range, the clamping force request is adjusted according to the comparison result, and a motor control is performed; The target range of the slip ratio is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle.

2. The redundant control method of the anti-lock braking system under the EMB system according to claim 1, characterized in that: The vehicle state includes vehicle speed, vehicle load, lateral acceleration, steering wheel angle, lateral acceleration and yaw rate.

3. The redundant control method of the anti-lock braking system under the EMB system according to claim 1, characterized in that: When the central domain controller operates normally, it determines the vehicle braking condition, determines the initial clamping force request based on the vehicle braking condition, adjusts the clamping force request based on the vehicle state after braking is triggered, calculates the slip rate based on the vehicle wheel speed, compares the slip rate with the slip rate target range, adjusts the clamping force request based on the comparison result, and sends the clamping force request to the wheel-end controller.

4. The redundant control method of the anti-lock braking system under the EMB system according to claim 1, characterized in that: The motor control steps include: calculating the clamping force based on the clamping force request, and obtaining the motor torque request according to the clamping force calculation result; estimating the torque that the motor can actually output; and driving the motor to apply the clamping force to the wheel according to the motor torque request and the estimation result.

5. Redundant control system of anti-lock braking system under EMB system, characterized by: Configured in the wheel end controller, including: A basic control module, which is configured to: perform motor control in response to a clamping force request transmitted from a central domain controller; The redundant control module is configured to: in response to a central domain controller fault signal, determine a vehicle braking condition, determine an initial clamping force request according to the vehicle braking condition, adjust the clamping force request according to the vehicle state after initiating braking, calculate a slip ratio based on a vehicle wheel speed, compare the slip ratio with a slip ratio target range, adjust the clamping force request according to the comparison result, and perform motor control; The target range of the slip ratio is adjusted according to the road condition obtained by identifying the road surface image in front of the vehicle.

6. The redundant control system of the anti-lock braking system under the EMB system as claimed in claim 5, characterized in that: The vehicle state includes vehicle speed, vehicle load, lateral acceleration, steering wheel angle, lateral acceleration and yaw rate.

7. The redundant control system of the anti-lock braking system under the EMB system as claimed in claim 5, characterized in that: When the central domain controller operates normally, it determines the vehicle braking condition, determines the initial clamping force request based on the vehicle braking condition, adjusts the clamping force request based on the vehicle state after braking is triggered, calculates the slip rate based on the vehicle wheel speed, compares the slip rate with the slip rate target range, adjusts the clamping force request based on the comparison result, and sends the clamping force request to the wheel-end controller.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps in the redundant control method of the anti-lock braking system in the EMB system as described in any one of claims 1 to 4 are implemented.

9. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps in the redundant control method of the anti-lock braking system in the EMB system are implemented as described in any one of claims 1-4.

10. A vehicle, characterized in that: Utilizing the redundant control method of the anti-lock braking system under the EMB system as described in any one of claims 1-4; or, including the redundant control system of the anti-lock braking system under the EMB system as described in any one of claims 5-7; or, including a computer-readable storage medium as described in claim 8; or, including a computer device as described in claim 9.

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