Emergency braking method and system based on dry brake

Abstract

The present invention discloses an emergency braking method and system based on dry brakes, which belongs to the field of vehicle braking technology and includes the following steps: S1, real-time monitoring of whether the chassis domain controller is working normally, and real-time detection of the EPB parking switch signal; S2, if it is detected that the EPB parking switch is pulled up, the chassis domain controller determines whether the driver performs emergency braking or other personnel on the vehicle assist in emergency braking; S3, if it is determined that the driver performs emergency braking, the EPB parking switch is pulled up for 300ms to obtain 60% of the maximum braking force; otherwise, the EPB parking switch is pulled up for 300ms to obtain 80% of the maximum braking force. The present invention adopts the above-mentioned emergency braking method and system based on dry brakes, which can realize the separate control of the four wheel brakes of the car, improve the vehicle stability and control performance, and at the same time, a backup brake is provided, which can effectively improve the safety during emergency braking.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle braking, and in particular to an emergency braking method and system based on a dry brake. Background Art

[0002] Dry brakes are brakes that work under dry friction conditions. The working principle of this type of brake mainly relies on dry friction, that is, direct friction braking without the participation of liquid media. Dry brakes usually include a brake disc or brake drum, and a brake pad or brake block that rubs against it. During the braking process, these brake components generate friction through direct contact, thereby achieving deceleration or stopping of the vehicle or other mechanical equipment.

[0003] When the car brakes fail, the driver will pull up the handbrake and try to downshift to use the engine for braking, but the handbrake is not very effective. The handbrake generally controls the rear wheels of the car. Due to the uneven road surface or the different braking forces of the left and right wheels, the vehicle will slide sideways, which may cause serious accidents such as rollovers. At the same time, many drivers do not use downshifts to achieve engine braking operations. For this reason, an emergency braking system is needed to achieve smooth braking of the car. Summary of the invention

[0004] The purpose of the present invention is to provide an emergency braking method and system based on dry brakes, which can realize independent control of the four wheel brakes of a car, improve the vehicle stability and control performance, and at the same time provide backup braking, which can effectively improve the safety during emergency braking.

[0005] To achieve the above object, the present invention provides an emergency braking method based on a dry brake, comprising the following steps:

[0006] S1. Real-time monitoring of whether the chassis domain controller is working properly. If the chassis domain controller is working properly, the chassis domain controller detects the EPB parking switch signal in real time;

[0007] S2: If the EPB parking switch is detected to be pulled up, the chassis domain controller calculates the vehicle speed in real time through the wheel speed sensor. If the vehicle speed is less than 7KPH, the chassis domain controller initiates a parking signal to the rear wheel mechanical brake EMB through CAN communication;

[0008] If the vehicle speed is not less than 7KPH and emergency braking is required, the chassis domain controller detects the accelerator pedal opening through the accelerator pedal position sensor. If the accelerator pedal opening is less than 5%, it is judged that the driver has performed emergency braking, otherwise it is judged that other people in the vehicle have assisted in emergency braking;

[0009] S3: If it is determined that the driver has applied emergency braking, the chassis domain controller controls the four mechanical brakes EMB through CAN communication to apply braking, and 60% of the maximum braking force is obtained 300ms after the EPB parking switch is pulled up;

[0010] If it is determined that other people in the vehicle are assisting in emergency braking, the power output will be cut off first, and then the chassis domain controller will control the four mechanical brakes EMB through CAN communication to brake. 80% of the maximum braking force will be obtained 300ms after the EPB parking switch is pulled up.

[0011] The present invention also provides an emergency braking system based on a dry brake, comprising an input module and an output module, wherein the input module comprises an EPB parking switch and a sensor assembly, wherein the sensor assembly comprises a wheel speed sensor and an accelerator pedal position sensor, and the output module comprises a chassis domain controller.

[0012] Preferably, the EPB parking switch, wheel speed sensor, and accelerator pedal position sensor are all electrically connected to the chassis domain controller.

[0013] Preferably, the chassis domain controller is electrically connected to a mechanical brake EMB, and the number of the mechanical brakes EMB is four, which are respectively arranged on the front and rear four wheels of the vehicle.

[0014] Preferably, the EPB parking switch is individually connected to four mechanical brakes EMB to provide backup braking force.

[0015] Therefore, the present invention adopts the above-mentioned emergency braking method and system based on dry brakes. Compared with traditional wet emergency brakes, dry emergency brakes have a faster braking reaction speed and are safer in emergency situations. At the same time, the braking system can control each wheel individually and can have more redundant backup braking force, so safety can still be guaranteed when the dry braking system partially fails.

[0016] At the same time, when the driver is unable to use the EPB emergency brake, other people in the car can pull up the EPB emergency brake switch to ensure safety in an emergency.

[0017] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further illustrated by the following examples.

[0019] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "include" or "comprise" and the like used in the present invention mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0020] Embodiment 1

[0021] The present invention provides a method for an emergency braking system based on a dry brake, comprising the following steps:

[0022] S1. Real-time monitoring of whether the chassis domain controller is working properly. If the chassis domain controller is working properly, the chassis domain controller detects the EPB parking switch signal in real time;

[0023] S2: If the EPB parking switch is detected to be pulled up, the chassis domain controller calculates the vehicle speed in real time through the wheel speed sensor. If the vehicle speed is less than 7KPH, the chassis domain controller initiates a parking signal to the rear wheel mechanical brake EMB through CAN communication;

[0024] If the vehicle speed is not less than 7KPH and emergency braking is required, the chassis domain controller detects the accelerator pedal opening through the accelerator pedal position sensor. If the accelerator pedal opening is less than 5%, it is judged that the driver has performed emergency braking, otherwise it is judged that other people in the vehicle have assisted in emergency braking;

[0025] S3: If it is determined that the driver has applied emergency braking, the chassis domain controller controls the four mechanical brakes EMB through CAN communication to apply braking. 60% of the maximum braking force is obtained 300ms after the EPB parking switch is pulled up, and a gradient braking force (10%, 30%, 60%) is obtained within 300ms.

[0026] If it is determined that other people in the vehicle are assisting in emergency braking, the power output will be cut off first, and then the chassis domain controller will control the four mechanical brakes EMB for braking through CAN communication. Three seconds after the EPB parking switch is pulled up, 80% of the maximum braking force will be obtained, and the gradient braking force (30%, 50%, 80%) will be obtained within 300ms.

[0027] Because the chassis domain controller can control each brake EMB individually through CAN communication, the vehicle can still be stably controlled for emergency braking in the event of partial system failure (EMB failure or CAN communication loss) during emergency braking. The specific control strategy is:

[0028] a. If the brakes of a single wheel fail, the maximum braking force of the other three normal wheels will be limited. For example, if the left front wheel fails, the braking force will be distributed to the other three wheels during emergency braking. The wheel diagonally opposite the failed wheel (right rear wheel) will be limited by the current acceleration. The greater the acceleration, the greater the limit value. The maximum limit values ​​of the other two wheels are the same as normal;

[0029] b. If the brakes on the same axle fail, the maximum braking force on the other axle will be limited. For example, if the front axle fails, the braking force will be distributed to the rear axle during emergency braking, and the maximum braking force limit value is the same as in normal situations;

[0030] c. If the brakes on the same side of the wheel fail, the maximum braking force on the other side will be limited. For example, if the left wheel fails, the braking force will be distributed to the right wheel for emergency braking. The maximum braking force limit value is limited by the current acceleration. The greater the acceleration, the greater the limit value.

[0031] If the chassis domain controller fails, the EPB parking switch directly controls the four mechanical brakes EMB to brake the four wheels and detects the current of each mechanical brake EMB motor in real time. When the current reaches the current that the EMB locks the tire, the EMB caliper will release until the current is lower than the calibrated threshold. When the current is lower than the calibrated threshold, the rear wheel brakes continue to provide braking force until the EPB parking switch is released.

[0032] The present invention also provides an emergency braking system based on a dry brake, comprising an input module and an output module, wherein the input module comprises an EPB parking switch and a sensor assembly, wherein the sensor assembly comprises a wheel speed sensor and an accelerator pedal position sensor, and the output module comprises a chassis domain controller.

[0033] The EPB parking switch, wheel speed sensor, and accelerator pedal position sensor are all electrically connected to the chassis domain controller. By controlling the EPB parking switch, the chassis domain controller can achieve corresponding control. The wheel speed sensor and accelerator pedal position sensor collect wheel speed sensor signals and accelerator pedal position signals, which can be transmitted to the chassis domain controller to facilitate the chassis domain controller to achieve subsequent braking control.

[0034] The chassis domain controller is electrically connected to the mechanical brake EMB, and there are four mechanical brakes EMB, which are respectively arranged on the front and rear wheels of the vehicle. The vehicle is braked by the mechanical brake EMB.

[0035] At the same time, the chassis domain controller integrates ABS, YSC and other functions, which can ensure the stability and safety of the vehicle even during emergency braking. When the EPB switch is pulled up for more than 3s and released, if the vehicle speed is less than 7KPH, the rear wheel mechanical brake EMB will start the parking function to prevent rolling. If the vehicle speed is still greater than 7KPH, the braking force will be linearly removed within 200ms.

[0036] The EPB parking switch is individually connected to the four mechanical brakes EMB to provide backup braking force. When the dry braking system partially fails, the vehicle can still be braked to ensure the safety of the passengers.

[0037] Therefore, the present invention adopts the above-mentioned emergency braking system based on dry brakes, which can realize independent control of the four wheel brakes of the vehicle, improve the vehicle stability and control performance, and at the same time provide backup braking, which can effectively improve the safety during emergency braking.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An emergency braking method based on a dry brake, characterized in that: The following steps are involved: S1. Real-time monitoring of whether the chassis domain controller is working properly. If the chassis domain controller is working properly, the chassis domain controller detects the EPB parking switch signal in real time; S2: If the EPB parking switch is detected to be pulled up, the chassis domain controller calculates the vehicle speed in real time through the wheel speed sensor. If the vehicle speed is less than 7KPH, the chassis domain controller initiates a parking signal to the rear wheel mechanical brake EMB through CAN communication; If the vehicle speed is not less than 7KPH and emergency braking is required, the chassis domain controller detects the accelerator pedal opening through the accelerator pedal position sensor. If the accelerator pedal opening is less than 5%, it is judged that the driver has performed emergency braking, otherwise it is judged that other people in the vehicle have assisted in emergency braking; S3: If it is determined that the driver has applied emergency braking, the chassis domain controller controls the four mechanical brakes EMB through CAN communication to apply braking, and 60% of the maximum braking force is obtained 300ms after the EPB parking switch is pulled up; If it is determined that other people in the vehicle assist in emergency braking, the power output is cut off first, and then the chassis domain controller controls the four mechanical brakes EMB to brake through CAN communication. 80% of the maximum braking force is obtained 300ms after the EPB parking switch is pulled up; Among them, the system of the emergency braking method based on the dry brake includes an input module and an output module. The input module includes an EPB parking switch and a sensor component. The sensor component includes a wheel speed sensor and an accelerator pedal position sensor. The output module includes a chassis domain controller.

2. The emergency braking method based on dry brake according to claim 1, characterized in that: The EPB parking switch, wheel speed sensor, and accelerator pedal position sensor are all electrically connected to the chassis domain controller.

3. The emergency braking method based on dry brake according to claim 2, characterized in that: The chassis domain controller is electrically connected to the mechanical brake EMB, and the number of the mechanical brake EMB is four, which are respectively arranged on the front and rear wheels of the vehicle.

4. The emergency braking method based on dry brake according to claim 3, characterized in that: The EPB parking switch is individually connected to four mechanical brakes EMB to provide backup braking force.