Brake-by-wire method and brake system under dual modes

Abstract

The invention discloses a brake-by-wire method and a brake system in dual modes, and belongs to the field of automobile braking, the brake-by-wire method and the brake system in dual modes comprise a pedal assembly, a vehicle control unit electrically connected with the pedal assembly and a brake-by-wire module electrically connected with the vehicle control unit, and the brake-by-wire module adopts a redundant structure. The brake-by-wire module comprises a main line control brake unit and a redundant brake-by-wire unit, and the main line control brake unit and the redundant brake-by-wire unit are connected with the brake calipers through brake connectors. By the adoption of the brake-by-wire method and the brake system under the double modes, the reliability, the safety and the response accuracy of the brake-by-wire system are remarkably improved through redundant acquisition of the brake intention by the double sensors, backup of the double brake-by-wire units and intelligent switching of the flow channels by the brake connector, stable and efficient operation of the brake function under the complex working condition is ensured, and the brake efficiency is improved. Therefore, the method is suitable for a normal driving mode and an automatic driving mode.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive braking, and particularly to a wire-controlled braking method and braking system in a dual mode. Background Art

[0002] With the development of automotive electrification and intelligent technologies, wire-controlled systems have gradually replaced traditional mechanical control systems. The wire-controlled system replaces mechanical connections through sensors and an electronic control unit (ECU), and transmits the driver's operation intention or autonomous driving signal in the form of an electrical signal to the actuator, achieving precise control of vehicle steering, acceleration, and braking. As a core actuator, the wire-controlled braking system significantly improves driving safety by adjusting the braking response speed and braking force in real time. At the same time, its integrated braking energy recovery function can effectively extend the cruising range of electric vehicles. Therefore, it plays a crucial role in electric vehicles, hybrid vehicles, and autonomous driving vehicles.

[0003] The typical technical solutions of existing wire-controlled braking systems are as follows: 1. In terms of signal transmission: The driver's braking intention (pedal travel or stepping force) is collected through a single sensor (such as an angle sensor or a force sensor), processed by the ECU, and then sent to the hydraulic control unit (HCU). The driving motor builds pressure and transmits it through the brake pipeline to the caliper to achieve braking. Using the above method, there is a risk of brake signal interruption due to sensor failure.

[0004] 2. In terms of structural composition: (1) Usually, a single braking unit design is adopted, lacking redundant backup. If the HCU or the motor fails, it may cause the vehicle's entire braking to fail, especially posing a major safety hazard in the autonomous driving scenario. (2) NVH (Noise, Vibration, and Harshness) performance defects: The traditional pedal structure adopts a fixed spring design, which is prone to generating noise due to mechanical vibration during braking and cannot effectively buffer the driver's stepping impact, affecting driving comfort. (3) Limited layout flexibility: Existing wire-controlled braking systems are mostly integrated structures, which need to be fixedly installed at a specific position in the vehicle's front cabin, making it difficult to adapt to the differences in engine compartment space of different vehicle models (such as compact cars and SUVs), increasing the complexity and cost of the vehicle design. Summary of the Invention

[0005] The purpose of the present invention is to provide a wire-controlled braking method and braking system in a dual mode to solve the above technical problems.

[0006] To achieve the above purpose, the present invention provides a wire-controlled braking method in a dual mode, including the following steps: S1. Determine the driver's braking intention and braking force in the normal driving mode or the autonomous driving mode, generate a braking instruction, and transmit the control instruction to the wire-controlled braking module; In step S1, in the normal driving mode, when the angle sensor collects the rotation angle of the pedal arm Or force sensor synchronously collects pedal force When it is greater than 0, it is determined that there is a braking intention, and when the rotation angle is set and pedaling force When they are main signal and auxiliary signal respectively, the braking force is calculated using the following formula: (1); In the formula, Indicates the travel-braking force coefficient; Indicates the angle-travel conversion factor; When setting the pedal force and rotation angle When they are main signal and auxiliary signal respectively, use the following formula to calculate the braking force : (2); In the formula, Indicates the piston area of ​​the brake master cylinder; In the autonomous driving mode, the vehicle's front environment is monitored in real time through the on-board sensors to identify obstacles or the distance to the vehicle in front. , set the minimum safety distance to ,when When the braking intention is determined, the braking force is calculated using the following formula : (3); In the formula, Indicates the vehicle mass; and Respectively represent the real-time vehicle speed and the relative speed between the current vehicle and the obstacle or the vehicle in front; S2, the ECU component of the wire control brake module obtains the brake pressure according to the received brake command; S3 and HCU components transfer the brake fluid in the reservoir to the brake caliper to perform braking.

[0007] Preferably, step S2 specifically includes the following steps: S21. Consider the piston area of ​​the brake caliper , calculate the brake pressure : (4); S22. Calculate the motor torque based on the efficiency of the HCU components : (5); In the formula, Represents the piston area of the HCU component; Represents the length of the transmission arm of the HCU component; And add the motor speed constraint: (6); In the formula, Represents the maximum speed of the motor; Represents the maximum linear velocity of the piston of the HCU component; Represents the transmission ratio of the HCU component; Represents the radius of the motor rotor.

[0008] Preferably, in step S3, when the main line control unit fails, switch to the redundant line control unit for control by using the brake connector, and compensate for the pipeline pressure loss: (7); Among them, (8); In the formula, Represents the compensation pressure; Represents the lost pressure value; Represents the friction coefficient between the brake fluid and the pipeline; Represents the length of the pipeline; Represents the pipeline diameter; Represents the density of the brake fluid; Represents the brake fluid velocity.

[0009] Preferably, in step S3, the brake fluid pressure of the HCU component is collected in real time and fed back to the ECU component. The ECU component adjusts the motor torque through the PID algorithm according to the fed-back brake fluid pressure to form a closed-loop control.

[0010] A braking system for implementing a by-wire braking method in a dual mode, including a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a by-wire braking module electrically connected to the vehicle controller. The by-wire braking module adopts a redundant structure. The by-wire braking module includes a main line control unit and a redundant line control unit. Both the main line control unit and the redundant line control unit are connected to the brake caliper through a brake connector.

[0011] Preferably, the pedal assembly includes a mounting shell arranged on the vehicle firewall and a pedal arm rotatably arranged at one end inside the mounting shell. The other end of the pedal arm extends out of the mounting shell and is fixedly connected to the brake pedal; An angle sensor is provided at the rotational connection between the pedal arm and the mounting housing, and a force sensor is provided at the power output end of the pedal arm via an elastic buffer assembly. Both the force sensor and the angle sensor are electrically connected to the output end of the vehicle controller. The vehicle controller determines the driver's braking intention and braking force based on the collected values of the force sensor and the angle sensor; The force sensor and the angle sensor are backup to each other.

[0012] Preferably, both the main line brake control unit and the redundant line brake control unit include a liquid storage pot, an HCU assembly communicated with the output end of the liquid storage pot, and an ECU assembly electrically connected to the HCU assembly. The ECU assemblies of the main line brake control unit and the redundant line brake control unit communicate with each other to achieve two-way backup; The ECU assembly is electrically connected to the vehicle controller and is used to receive the braking signal output by the vehicle controller by means of the ECU assembly and calculate the braking pressure and the motor torque according to the braking signal.

[0013] Therefore, the present invention adopts the above-mentioned wire-controlled braking method and braking system in a dual mode, and has the following beneficial effects: 1. High-reliability redundancy design: The two wire-controlled braking modules are backup to each other. When the primary module fails, the backup module can immediately take over to ensure that the braking function is not interrupted and avoid braking failure caused by the failure of a single unit; 2. Precise signal acquisition and processing: Dual sensors (angle and force sensors) are used for redundant acquisition of the braking intention, and the accuracy of the input signal is improved through a signal verification mechanism to prevent misjudgment caused by the failure of a single sensor and ensure the reliable transmission of the braking intention; 3. Intelligent flow channel switching and isolation: The braking connector can switch the flow channel according to the system state to isolate the faulty unit, ensuring the stable transmission of the braking fluid pressure to the caliper, improving the safety and fault tolerance of the braking system, and effectively coping with complex working conditions; 4. Precise pressure control: The ECU and the HCU assembly work together to quickly and precisely establish the braking pressure through precise control of the motor torque and pressure closed-loop regulation, meeting the high-dynamic and high-precision requirements of braking response in scenarios such as autonomous driving; 6. Flexible system adaptability: The design of independent installation of the wire-controlled braking unit and the braking connector enables it to be flexibly arranged according to the engine compartment space of different vehicle models, enhancing the applicability and expandability of the solution and facilitating its application on a variety of vehicle platforms.

[0014] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the principle block diagram of the braking system of the present invention; Figure 2 Circuit diagram of the wire control brake module of the brake system of the present invention; Figure 3 Schematic structural diagram of the wire control brake module of the brake system of the present invention; Figure 4 Schematic structural diagram of one perspective of the brake connector of the brake system of the present invention; Figure 5 Schematic structural diagram of another perspective of the brake connector of the brake system of the present invention; Figure 6 Cross-sectional view of the pedal assembly of the brake system of the present invention; Figure 7 External view of the pedal assembly of the brake system of the present invention; Figure 8 Flow chart of a wire control braking method in a dual mode of the brake system of the present invention.

[0016] Reference numerals 1. Liquid storage pot; 2. HCU assembly; 3. ECU assembly; 4. Two-position three-way valve; 5. Force sensor; 6. Angle sensor; 7. Pedal arm; 8. Elastic buffer assembly; 9. Mounting shell; 10. Brake pedal. Detailed implementation manners

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following further describes the embodiments of the present invention in detail with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of this application. Examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0018] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or server that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0019] The following further describes the embodiments of the present invention in detail with reference to the drawings.

[0020] As Figures 1-7As shown in the figure, a braking system includes a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a wire-controlled braking module electrically connected to the vehicle controller. The wire-controlled braking module adopts a redundant structure. The wire-controlled braking module includes a main wire-controlled braking unit and a redundant wire-controlled braking unit. Both the main wire-controlled braking unit and the redundant wire-controlled braking unit are connected to the brake caliper through a braking connector. In this embodiment, the braking connector includes a valve body, an FL (front left) liquid inlet, an RR (rear right) liquid inlet, an RL (rear left) liquid inlet, and an FR (front right) liquid inlet arranged on one side of the valve body, an FL liquid outlet, an RR liquid outlet, an RL liquid outlet, and an FR liquid outlet arranged on the other side of the valve body. The FL liquid inlet, RR liquid inlet, RL liquid inlet, and FR liquid inlet are respectively communicated with the FL liquid outlet, RR liquid outlet, RL liquid outlet, and FR liquid outlet through flow channels arranged in the valve body. Two-position three-way valves 4 for controlling FL, RR, RL, and FR respectively are arranged on the valve body to realize the switching between the main wire-controlled braking unit and the redundant wire-controlled braking unit by using the two-position three-way valves 4.

[0021] The pedal assembly includes an installation shell 9 arranged on the vehicle firewall and a pedal arm 7 rotatably arranged at one end inside the installation shell 9. The other end of the pedal arm 7 extends out of the installation shell 9 and is fixedly connected to the brake pedal 10; an angle sensor 6 is arranged at the rotational connection between the pedal arm 7 and the installation shell 9, and a force sensor 5 is arranged at the power output end of the pedal arm 7 through an elastic buffer assembly 8. Both the force sensor 5 and the angle sensor 6 are electrically connected to the output end of the vehicle controller. The vehicle controller determines the driver's braking intention and braking force according to the collected values of the force sensor 5 and the angle sensor 6; the force sensor 5 and the angle sensor 6 are backup to each other.

[0022] In this embodiment, the elastic buffer assembly 8 is a spring, a disc spring or a rubber with high stiffness, which is used to increase the pedal rod and reduce the braking noise.

[0023] Both the main wire-controlled braking unit and the redundant wire-controlled braking unit include a liquid storage pot 1, an HCU assembly 2 communicated with the output end of the liquid storage pot 1, and an ECU assembly 3 electrically connected to the HCU assembly 2. The ECU assembly 3 of the main wire-controlled braking unit communicates with the ECU assembly 3 of the redundant wire-controlled braking unit to achieve two-way backup; the ECU assembly 3 is electrically connected to the vehicle controller, and is used to receive the braking signal output by the vehicle controller by using the ECU assembly 3 and calculate the braking pressure and motor torque according to the braking signal.

[0024] A wire-controlled braking method in a dual mode includes the following steps: S1. Determine the driver's braking intention and braking force in the normal driving mode or the autonomous driving mode, generate a braking instruction, and transmit the control instruction to the wire-controlled braking module; In step S1, in the normal driving mode, when the angle sensor collects the rotation angle of the pedal arm Or force sensor synchronously collects pedal force When it is greater than 0, it is determined that there is a braking intention, and when the rotation angle is set and pedaling force When they are main signal and auxiliary signal respectively, the braking force is calculated using the following formula: (1); In the formula, Indicates the travel-braking force coefficient; Indicates the angle-travel conversion factor; When setting the pedal force and rotation angle When they are main signal and auxiliary signal respectively, use the following formula to calculate the braking force : (2); In the formula, Indicates the piston area of ​​the brake master cylinder; In the autonomous driving mode, the vehicle's front environment is monitored in real time through the on-board sensors to identify obstacles or the distance to the vehicle in front. , set the minimum safety distance to ,when When the braking intention is determined, the braking force is calculated using the following formula : (3); In the formula, Indicates the vehicle mass; and They respectively represent the real-time vehicle speed and the relative speed between the current vehicle and the obstacle or the vehicle in front.

[0025] S2, the ECU component of the wire control brake module obtains the brake pressure according to the received brake command; Step S2 specifically includes the following steps: S21. Consider the piston area of ​​the brake caliper , calculate the brake pressure : (4); S22. Calculate the motor torque based on the efficiency of the HCU components : (5); In the formula, Indicates the piston area of ​​the HCU assembly; Indicates the length of the transmission arm of the HCU assembly; And add the motor speed constraint: (6); Wherein, represents the maximum speed of the motor; represents the maximum linear velocity of the piston of the HCU assembly; represents the transmission ratio of the HCU assembly; represents the radius of the motor rotor.

[0026] S3. The HCU assembly transfers the brake fluid in the reservoir to the brake caliper to perform braking.

[0027] In step S3, when the main line control braking unit fails, switch to the redundant line control braking unit for control by using the brake connector, and compensate for the pipeline pressure loss: (7); Wherein, (8); Wherein, represents the compensation pressure; represents the lost pressure value; represents the friction coefficient between the brake fluid and the pipeline; represents the length of the pipeline; represents the pipeline diameter; represents the density of the brake fluid; represents the brake fluid velocity.

[0028] Preferably, in step S3, the brake fluid pressure of the HCU assembly is collected in real time and fed back to the ECU assembly. The ECU assembly adjusts the motor torque through the PID algorithm according to the fed-back brake fluid pressure to form a closed-loop control.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A wire braking method in a dual mode, characterized in that: It includes the following steps: S1. Determine the braking intention and braking force of the driver in the normal driving mode or the autonomous driving mode, generate a braking instruction, and transmit the control instruction to the electronic brake system module; In step S1, in the normal driving mode, when the angle sensor collects the rotation angle of the pedal arm Or force sensor synchronously collects pedal force When it is greater than 0, it is determined that there is a braking intention, and when the rotation angle is set and pedaling force When they are main signal and auxiliary signal respectively, the braking force is calculated using the following formula: （1）； In the formula, represents the travel-braking force coefficient; represents the angle-travel conversion coefficient; When the set pedal force and the rotation angle are the main signal and the auxiliary signal respectively, calculate the braking force using the following formula : （2）； In the formula, represents the piston area of the master cylinder for braking; In the autonomous driving mode, the vehicle's front environment is monitored in real time through in-vehicle sensors to identify obstacles or the distance to the vehicle ahead , and the minimum safety distance is set to . When , it is determined that a braking intention is generated, and the braking force is calculated using the following formula : （3）； In the formula, represents the vehicle mass; and respectively represent the real-time vehicle speed and the relative speed between the current vehicle and an obstacle or the vehicle ahead; S2. The ECU component of the electronic brake system module obtains the braking pressure according to the received braking instruction; S3. The HCU component transfers the brake fluid in the reservoir to the brake caliper to perform braking.

2. The wire braking method in a dual mode according to claim 1, characterized in that: Step S2 specifically includes the following steps: S21. Consider the piston area of the brake caliper , and calculate the braking pressure : （4）； S22. Calculate the motor torque based on the efficiency of the HCU component : （5）； In the formula, represents the piston area of the HCU assembly; represents the length of the drive arm of the HCU assembly; And add a motor speed constraint: （6）； In the formula, represents the maximum rotational speed of the motor; represents the maximum linear velocity of the piston of the HCU assembly; represents the transmission ratio of the HCU assembly; represents the radius of the motor rotor.

3. A wire braking method in a dual mode according to claim 2, characterized in that: In step S3, when the main electronic brake control unit fails, switch to the redundant electronic brake system unit control by using the brake connector, and compensate for the pipeline pressure loss: （7）； Wherein, （8）； Wherein, represents the compensation pressure; represents the lost pressure value; represents the friction coefficient between the brake fluid and the pipeline; represents the length of the pipeline; represents the pipeline diameter; represents the density of the brake fluid; represents the brake fluid velocity.

4. The wire braking method in a dual mode according to claim 3, wherein: In step S3, the brake fluid pressure of the HCU component is collected in real time and fed back to the ECU component. The ECU component adjusts the motor torque through the PID algorithm according to the fed-back brake fluid pressure to form a closed-loop control.

5. A braking system for implementing the wire-controlled braking method in a dual mode described in claim 4 above, comprising a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a wire-controlled braking module electrically connected to the vehicle controller, characterized in that: The electronic brake system module adopts a redundant structure. The electronic brake system module includes a main electronic brake control unit and a redundant electronic brake system unit. Both the main electronic brake control unit and the redundant electronic brake system unit are connected to the brake caliper through the brake connector.

6. A braking system according to claim 5, characterized in that: The pedal assembly includes a mounting shell arranged on the vehicle firewall and a pedal arm rotatably arranged at one end inside the mounting shell. The other end of the pedal arm extends out of the mounting shell and is fixedly connected to the brake pedal; An angle sensor is provided at the rotational connection between the pedal arm and the mounting shell, and a force sensor is arranged at the power output end of the pedal arm through an elastic buffer assembly. Both the force sensor and the angle sensor are electrically connected to the output end of the vehicle controller. The vehicle controller determines the braking intention and braking force of the driver according to the collected values of the force sensor and the angle sensor; The force sensor and the angle sensor are backup to each other.

7. A braking system according to claim 6, characterized in that: Both the main electronic brake control unit and the redundant electronic brake system unit include a reservoir, an HCU component communicated with the output end of the reservoir, and an ECU component electrically connected to the HCU component. The ECU component of the main electronic brake control unit communicates with the ECU component of the redundant electronic brake system unit to achieve two-way backup; The ECU component is electrically connected to the vehicle controller, and is used to receive the braking signal output by the vehicle controller by using the ECU component, and calculate the braking pressure and motor torque according to the braking signal.

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