A dual electronic hydraulic brake system with redundant function

Abstract

The present invention relates to the field of vehicle electric hydraulic brake redundancy technology, and in particular to a dual electronic hydraulic brake system with redundant functions, including a first electronic hydraulic brake, a second electronic hydraulic brake, an ESC and a wheel brake, wherein the first electronic hydraulic brake and the second electronic hydraulic brake are both connected to the ESC through a brake line, and the ESC is further connected to the wheel brake through the brake line. The present invention solves the problem of braking force distribution for unmanned vehicles with two-way driving, while maximizing the synchronous adhesion coefficient, and the front and rear brakes can use brakes of the same specifications. Two electronic hydraulic brakes and one ESC realize triple braking redundancy, which improves the safety of the vehicle during driving, prevents the vehicle from losing control due to failure of one of the electronic hydraulic brakes of the vehicle, and avoids serious accidents.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle electric hydraulic brake redundancy, and in particular to a dual electronic hydraulic brake system with redundancy function. Background Art

[0002] In recent years, autonomous and intelligent driving technologies for electric vehicles have developed rapidly, with increasingly advanced levels of autonomous driving. This has led to higher requirements for vehicle safety performance. In particular, the design of braking force distribution solutions for braking systems is becoming increasingly important.

[0003] Currently, most autonomous vehicles utilize a single electronic hydraulic braking system. This system distributes braking force between the front and rear axles by selecting brakes of different cylinder diameters or sizes. However, this braking force distribution solution is not suitable for autonomous vehicles traveling in both directions. Traditional single electronic hydraulic braking systems present certain risks. If the system fails, the vehicle's braking capacity will be severely affected, which can easily lead to loss of control and serious traffic accidents. Furthermore, while existing electronic hydraulic braking systems have certain control strategies for braking force distribution, there is still room for improvement to further enhance braking precision and stability. Summary of the Invention

[0004] The purpose of the present invention is to address the problems existing in the background technology of bidirectional unmanned vehicles, and to propose an electronic brake redundancy structure that solves the problem of braking force distribution of bidirectional unmanned minibuses through the arrangement of an electronic hydraulic brake system, and can still provide braking force when the electronic hydraulic brake system fails.

[0005] The technical solution of the present invention is a dual electronic hydraulic brake system with redundancy, comprising a first electronic hydraulic brake, a second electronic hydraulic brake, an electronic stability control system (ESC), and wheel brakes. Both the first and second electronic hydraulic brakes are connected to the ESC via brake lines, which in turn are connected to the wheel brakes via brake lines.

[0006] Furthermore, during braking, the BCU calculates the total braking force and the ideal braking force distribution ratio between the front and rear wheels based on the vehicle's driving state information, and controls the first and second electronic hydraulic brakes to establish different hydraulic pressures to generate different braking forces.

[0007] Specifically, the vehicle's brake control unit BCU calculates the required total braking force and the ideal braking force distribution ratio between the front and rear wheels based on the vehicle's driving status information, such as vehicle speed, wheel speed, vehicle load, etc. Then, the brake control unit BCU sends control signals to the first electronic hydraulic brake and the second electronic hydraulic brake respectively, so that the two work together. The first electronic hydraulic brake and the second electronic hydraulic brake establish different hydraulic pressures based on the received signals, thereby generating different braking forces. For example, during normal braking, if the vehicle's braking force requirement is F, the brake control unit BCU can control the first electronic hydraulic brake to generate braking force F1 and the second electronic hydraulic brake to generate braking force F2, and F1+F2=F. By precisely adjusting the sizes of F1 and F2, a braking force distribution that is closer to the ideal braking force distribution curve can be achieved, thereby improving braking efficiency and stability.

[0008] Furthermore, when the first electronic hydraulic brake fails, the second electronic hydraulic brake can independently assume the braking task, ensuring that the vehicle still has sufficient braking force to slow down and stop, preventing the vehicle from losing control; when the second electronic hydraulic brake fails, the first electronic hydraulic brake can independently assume the braking task.

[0009] Furthermore, during electronic parking braking, if one of the electronic hydraulic brakes fails, the other electronic hydraulic brake can apply parking braking force to the wheel brakes through the ESC to prevent the vehicle from rolling.

[0010] For example, when the vehicle is parked on a slope, even if the first electronic hydraulic brake fails, the second electronic hydraulic brake can provide stable parking hydraulic pressure to the wheel brakes through ESC according to the instructions of the BCU to ensure the parking safety of the vehicle.

[0011] Compared with the prior art, the present invention has the following beneficial technical effects: it adds another electronic hydraulic brake system on the basis of the current mainstream electronic hydraulic brake system, and the two electronic hydraulic brakes have different pressure build-up, which can more effectively solve the problem of braking force distribution. At the same time, it can also achieve the redundancy of electronic braking. When one of the electronic hydraulic brake systems fails, the other electronic hydraulic brake system can still provide braking force to the vehicle, thereby improving the safety of the vehicle during driving, preventing the vehicle from losing control due to failure of the vehicle's brake system, and avoiding serious accidents. In addition, electronic parking brake redundancy can also be achieved. The two electronic hydraulic brakes are connected to the electronic stability control system ESC through brake pipes, and the electronic stability control system ESC is connected to the wheel side brakes through brake pipes. When one of the electronic hydraulic brakes fails, the other electronic hydraulic brake system can still provide parking braking force to the vehicle to prevent the vehicle from slipping, thereby improving vehicle safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of a dual electronic hydraulic brake system with redundant function;

[0013] Reference numerals: 1. oil tank; 2. first electronic hydraulic brake; 3. ESC; 4. wheel brake; 5. second electronic hydraulic brake.

[0014] Glossary: ​​ESC: Electronic Stability Control System; BCU: Brake Control Unit. DETAILED DESCRIPTION

[0015] The following is a clear and complete description of the technical solution of this invention in conjunction with the accompanying drawings. Obviously, the invention described is only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this invention.

[0016] Example

[0017] Early traditional vehicles used a fixed ratio to distribute braking force. When designing a vehicle's braking system, a predetermined ratio of front and rear wheel braking force distribution is determined based on factors such as the vehicle's axle load distribution.

[0018] For example, some vehicles are designed to distribute the front and rear wheel braking force in a ratio of 2 or 4. This distribution is mainly based on the average axle load distribution and braking demand of the vehicle under most common operating conditions.

[0019] When the brake control unit (BCU) sends a brake signal via the CAN, the hydraulic pressure generated by the master cylinder is transmitted through the brake lines to the front and rear wheel cylinders. Designs such as proportional valves and differential pipe diameters in the front and rear wheel brake lines ensure that the front and rear wheels receive braking force in a predetermined, fixed ratio.

[0020] However, this fixed-ratio distribution method has limitations. Under different road adhesion conditions (such as dry roads, wet roads) and vehicle load conditions (empty, fully loaded), the fixed ratio may not guarantee that the front and rear wheels lock at the same time, which can easily lead to the front wheels locking first or the rear wheels locking first when the vehicle brakes. If the front wheels lock first, the vehicle will lose its steering ability, and if the rear wheels lock first, it will cause the vehicle to skid, seriously affecting the safety and stability of the vehicle's braking. In particular, unmanned minibuses that can travel in both directions normally require that the front wheel braking force be greater than the rear wheel braking force. However, minibuses that travel in both directions cannot distinguish between the front and rear wheels, so the above traditional solutions cannot meet the braking force distribution problem of unmanned minibuses that travel in both directions.

[0021] like Figure 1As shown, the present invention proposes a dual electronic hydraulic brake system with redundancy, suitable for distributing braking force on bidirectional driverless minibuses. Two electronic hydraulic brakes are used to address the vehicle's braking force distribution. The system includes an oil reservoir 1, an electronic hydraulic brake 2, an ESC 3, and a wheel brake 4. The first electronic hydraulic brake 2 and the second electronic hydraulic brake 5 are each connected to the ESC 3 and then to the wheel 4 via brake lines. The line arrangement is not limited to one type of arrangement. Each electronic hydraulic brake 2 and the second electronic hydraulic brake 5 are controlled via CAN bus. A brake control unit (BCU) is connected to the electronic hydraulic brake 2 and the ESC 3 via the CAN bus. Under normal operation, the first and second electronic hydraulic brakes 2 and 5 operate simultaneously. If one electronic hydraulic brake fails, the other can still operate normally, allowing the vehicle to brake. The first and second electronic hydraulic brakes 2 and 5 can operate independently or simultaneously.

[0022] The first electronic hydraulic brake 2 and the second electronic hydraulic brake 5 share the same oil tank 1 and are connected to the oil inlet of the ESC 3 through a brake pipeline. Then, the brake fluid flows from the ESC 3 to the four wheel brakes 4.

[0023] During the vehicle's brake system assembly, install the first and second electronic hydraulic brakes 2 and 5 in appropriate locations on the vehicle chassis and connect them to the ESC 3 via brake lines. Ensure the connections are secure and well-sealed. Also, properly install and debug the brake lines connecting the ESC 3 to the wheel brakes 4.

[0024] After the vehicle is started, the brake control unit BCU collects various driving status information of the vehicle in real time, including wheel speed information from the wheel speed sensor, vehicle acceleration information from the acceleration sensor, brake line pressure information from the pressure sensor, and vehicle load information (which can be comprehensively judged through seat sensors, suspension sensors, etc.).

[0025] When the brake control unit (BCU) sends a brake signal via the CAN, it calculates the required total braking force and the braking force distribution ratio between the front and rear wheels based on the collected information and a preset braking algorithm. The BCU then sends corresponding control signals to the first and second electronic hydraulic brakes 2 and 5, controlling the operation of their motors and the hydraulic pumps to generate hydraulic pressure. For example, during light braking, the BCU can control the first electronic hydraulic brake 2 to generate a smaller braking force on the front wheels and the second electronic hydraulic brake 5 to generate a relatively larger braking force on the rear wheels based on the vehicle's axle load distribution and current speed, achieving optimal braking force distribution and improving braking smoothness.

[0026] During braking, the BCU continuously monitors the operating status of the first and second electronic hydraulic brakes 2 and 5, including whether the hydraulic pressure is normal and whether the motor is functioning properly. If a fault is detected in the first electronic hydraulic brake 2, such as a hydraulic pump failure preventing pressure buildup or a motor short circuit, the BCU immediately adjusts its control strategy, transferring all or part of the braking force originally allocated to the first electronic hydraulic brake 2 to the second electronic hydraulic brake 5. The BCU also displays a brake system fault message on the vehicle's instrument panel, reminding the driver to drive with caution and have the vehicle repaired as soon as possible.

[0027] After receiving the parking signal, the BCU first checks the status of the first electronic hydraulic brake 2 and the second electronic hydraulic brake 5. If both are working normally, the BCU can reasonably distribute the parking braking force to the two electronic hydraulic brakes according to factors such as the parking position of the vehicle (such as whether it is on a slope) and the weight of the vehicle, and transmit it to the wheel brakes through the ESC 3 to achieve parking. If one of the electronic hydraulic brakes fails, the BCU only controls the normal electronic hydraulic brake to generate sufficient parking braking force to ensure that the vehicle does not slip. Alternatively, when the vehicle needs to perform electronic parking braking, the unmanned minibus uses the parking EPB to achieve parking redundancy. From the start of braking to stopping, the electronic parking EPB is first pulled up to achieve parking, and the first electronic hydraulic brake 2 and the second electronic hydraulic brake 5 are then depressurized.

[0028] The control method of this system includes the following steps:

[0029] Step 1: When the vehicle is started, the ESC 3 performs a self-check to ensure that the first electronic hydraulic brake 2 and the second electronic hydraulic brake 5 are in normal working condition;

[0030] Step 2: During vehicle driving, ESC 3 monitors vehicle speed, steering angle, acceleration and other parameters in real time;

[0031] Step 3: When the vehicle receives a braking command, ESC 3 calculates and determines the braking force distribution ratio between the front and rear wheels based on the current driving direction and vehicle status;

[0032] Step 4: The ESC sends a control signal to the first electronic hydraulic brake 2 and the second electronic hydraulic brake 5 to adjust the brake pressure to achieve the calculated braking force distribution ratio;

[0033] Step 5: Brake fluid is pressed into the wheel brakes through the brake pipes, generating braking friction to slow down or stop the vehicle.

[0034] Step 6: During the braking process, if either the first electronic hydraulic brake 2 or the second electronic hydraulic brake 5 fails, the ESC 3 immediately adjusts the pressure of the other brake to ensure that the vehicle has at least half of its braking capacity;

[0035] Step 7: After braking, ESC 3 records the operating data of the braking system for subsequent analysis and maintenance.

[0036] By adding an electronic hydraulic braking system, the present invention can not only distribute the braking force more accurately and improve the braking performance, but also provide redundancy protection when the braking system components fail. Whether it is service braking or parking braking, it greatly improves the safety of the vehicle and effectively avoids vehicle loss of control and rolling accidents caused by braking system failure.

[0037] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant inspirations of the above embodiments, those skilled in the art may make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A dual electronic hydraulic brake system with redundant function, characterized in that: The invention comprises a first electronic hydraulic brake (2), a second electronic hydraulic brake (5), an ESC (3) and a wheel side brake (4); the first electronic hydraulic brake (2) and the second electronic hydraulic brake (5) are both connected to the ESC (3) via a brake pipeline, and the ESC (3) is further connected to the wheel side brake (4) via the brake pipeline.

2. The dual electronic hydraulic brake system with redundant function according to claim 1, characterized in that: During the braking process, the BCU calculates the total braking force and the ideal braking force distribution ratio between the front and rear wheels according to the vehicle driving state information, and controls the first electronic hydraulic brake (2) and the second electronic hydraulic brake (5) to establish different hydraulic pressures to generate different braking forces.

3. The dual electronic hydraulic brake system with redundant function according to claim 1, characterized in that: When the first electronic hydraulic brake (2) fails, the second electronic hydraulic brake (5) can independently undertake the braking task; when the second electronic hydraulic brake (5) fails, the first electronic hydraulic brake (2) can independently undertake the braking task.

4. The dual electronic hydraulic brake system with redundant function according to claim 1, characterized in that: During the electronic parking brake, if one of the electronic hydraulic brakes fails, the other electronic hydraulic brake can apply parking braking force to the wheel brake (4) through the ESC (3) to prevent the vehicle from rolling.

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