Vehicle brake control method, system and vehicle

Abstract

The application relates to the technical field of new energy vehicles, in particular to a vehicle braking control method and system and a vehicle. The method comprises the following steps: when the brake pedal opening degree is less than or equal to a first preset threshold value and the accelerator pedal opening degree is less than or equal to a third preset threshold value, whether the vehicle braking is effective is judged according to a brake switch signal; if the brake switch is effective, the vehicle braking is effective; if the brake switch signal is invalid, the vehicle exits the braking mode. The judgment whether to enter the braking mode when the brake pedal opening degree is less than or equal to the first preset threshold value and the accelerator pedal opening degree is less than or equal to the third preset threshold value is completed, the braking intention of the driver is more reasonably judged, and the reliability of the vehicle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a vehicle brake control method, system and vehicle, and belongs to the technical field of new energy vehicles. BACKGROUND

[0002] At present, new energy vehicles have become the development trend of today's vehicles. In new energy vehicles, the brake pedal signal is one of the important input signals of vehicle control. The brake pedal signal is used as an input judgment condition in functions such as vehicle energy feedback calculation and vehicle brake mode judgment.

[0003] Most of the traditional brake pedals in the industry use two mechanical brake switches, one is always open, and the other is always closed. This method can only determine whether the brake pedal is stepped down, and cannot determine the pedal depression depth. The vehicle controller cannot match the corresponding energy feedback according to the pedal depth, which negatively affects the economy of new energy vehicles. In addition, due to the use of mechanical switches, the wear of mechanical parts will cause the switch to fail after a long time of use. The Chinese patent application with the application publication number CN106515686A discloses a brake pedal controller, a brake pedal signal processing method and a brake pedal. The opening degree signal under different brake pedal depths is obtained by processing and analyzing the signals of multiple sensors such as the active controller, pressure sensor and two angle sensors. Due to the use of multiple sensors, the hardware cost is increased, and the processing and calibration work of multiple sensor signals is increased, which increases the development cycle cost. SUMMARY

[0004] The purpose of the present application is to provide a vehicle brake control method, system and vehicle to solve the problem of inaccurate driver brake control intention judgment caused by brake switch voltage zero drift in the prior art.

[0005] To achieve the above-mentioned purpose, the scheme of the present application includes:

[0006] A vehicle brake control method, after the vehicle is powered on, when the brake pedal opening degree is less than or equal to a first preset threshold, and the accelerator pedal opening degree is less than or equal to a third preset threshold, the vehicle brake control method judges whether the vehicle enters a brake mode according to a brake switch signal; if the brake switch signal is valid, the vehicle enters the brake mode; if the brake switch signal is invalid, the vehicle does not enter the brake mode.

[0007] Beneficial Effects: Given that drivers may accidentally press the brake pedal, this invention does not solely rely on brake pedal opening to identify the driver's braking intention. Instead, it comprehensively analyzes and identifies multiple signals to accurately determine the driver's braking intention. These signals include the brake switch status, brake pedal opening, and accelerator pedal switch signal. By integrating these signals, it accurately determines whether the vehicle has entered braking mode. Specifically, after the vehicle is powered on, when the brake pedal opening is less than or equal to a first preset threshold and the accelerator pedal opening is less than or equal to a third preset threshold, the brake switch signal is used to determine whether the vehicle's braking is effective, thus completing the determination of whether braking mode has been entered. This more reasonable analysis and judgment of the driver's braking intention improves vehicle reliability.

[0008] Furthermore, the method for determining whether the brake switch signal is valid is as follows: after the vehicle is powered on and the brake pedal and accelerator pedal are released, if the mechanical brake switch is not faulty and is valid, or if the mechanical brake switch is faulty and the brake pedal opening signal is greater than the second preset threshold, then the brake switch signal is determined to be valid; otherwise, the brake switch signal is determined to be invalid. Here, the mechanical brake switch failure and non-failure are used to characterize whether the mechanical brake switch is faulty, and whether the mechanical brake switch is valid is used to characterize the state of the mechanical brake switch.

[0009] Beneficial effects: It completes the determination of whether the brake switch signal is valid, ensuring the determination of whether the vehicle has entered braking mode.

[0010] Furthermore, mechanical brake switch failure includes normally closed mechanical brake switch failure and normally open mechanical brake switch failure; if the mechanical brake switch remains valid for a longer period than a first preset time and the throttle switch signal changes from invalid to valid during this period, the mechanical brake switch is determined to be normally closed failure; if the brake pedal opening is greater than the fourth preset threshold for a longer period than the second preset time and the mechanical brake switch remains invalid, the mechanical brake switch is determined to be normally open failure.

[0011] Beneficial effects: This function determines whether the mechanical brake switch has failed, specifically identifying whether the failure is due to a normally closed or normally open switch malfunction. This ensures the effectiveness of the braking system.

[0012] Furthermore, the formula for calculating the brake pedal opening is:

[0013]

[0014] Where U0 is the zero-position voltage, U max U is the maximum voltage of the brake pedal, U is the actual voltage value of the brake pedal angle sensor, and ∝ is the brake pedal opening.

[0015] Beneficial effect: The above formula can be used to calculate the brake pedal opening.

[0016] Further, the method for judging whether the accelerator switch signal is valid is that if the accelerator pedal opening degree is greater than the third preset threshold, the accelerator switch signal is valid, otherwise, the accelerator switch signal is invalid.

[0017] Beneficial effect: complete the judgment of whether the accelerator switch signal is valid, and guarantee the judgment of whether the mechanical brake switch is invalid.

[0018] Further, if the brake pedal opening degree is greater than the first preset threshold, the vehicle enters the brake mode.

[0019] Beneficial effect: complete the judgment of whether the vehicle enters the brake mode when the brake pedal opening degree is greater than the first preset threshold.

[0020] Further, if the brake pedal opening degree is less than or equal to the first preset threshold and the accelerator pedal opening degree is greater than the third preset threshold, the brake is invalid, and the vehicle does not enter the brake mode.

[0021] Beneficial effect: complete the judgment of whether the vehicle enters the brake mode when the brake pedal opening degree is less than or equal to the first preset threshold and the accelerator pedal opening degree is greater than the third preset threshold.

[0022] Further, when the mechanical brake switch is switched from valid to invalid for a plurality of times continuously, the mechanical brake switch normally closed invalidity judgment is exited; when the mechanical brake switch is switched from invalid to valid for a plurality of times continuously, the mechanical brake switch normally open invalidity judgment is exited.

[0023] Beneficial effect: when the mechanical brake switch meets the condition of being switched from valid to invalid for a plurality of times continuously, it is determined that the mechanical brake switch normally closed invalidity judgment is not needed; when the mechanical brake switch is switched from invalid to valid for a plurality of times continuously, it is determined that the mechanical brake switch normally open invalidity judgment is not needed.

[0024] The application also provides a vehicle brake control system, which comprises a control module and an acquisition module, the acquisition module is used for acquiring brake pedal opening degree and accelerator pedal opening degree, and is connected with the control module to send the acquired data to the control module, and the control module is used for executing computer program instructions to realize the vehicle brake control method.

[0025] Beneficial effect: the system completes the judgment of whether the brake is valid, more reasonably judges the brake intention of the driver, and improves the reliability of the vehicle.

[0026] The application also provides a vehicle comprising the vehicle brake control system.

[0027] Beneficial effect: by using the vehicle brake control system on the vehicle, the intention of the driver can be more reasonably judged, and the reliability of the vehicle is improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a vehicle brake control method flowchart of the present application;

[0029] Figure 2 is a brake switch signal validity determination method flowchart of the present application. DETAILED DESCRIPTION

[0030] The concept of the present application is to determine whether the vehicle enters the brake mode in combination with the brake switch state and the brake pedal opening size, and to obtain the throttle pedal switch signal when determining, first determine whether the brake pedal opening is greater than the first preset threshold, if satisfied, determine that the vehicle enters the brake mode; if not satisfied, determine according to the throttle pedal state, if the throttle pedal opening is greater than the third preset threshold, determine that the vehicle exits the brake mode; if not satisfied, determine whether the vehicle enters the brake mode according to the brake switch signal. If the brake switch signal is valid, it is determined that the vehicle enters the brake mode; if the brake switch signal is invalid, it is determined that the vehicle exits the brake mode. More reasonable to determine the driver's braking intention, improve the reliability of the vehicle.

[0031] The present application will be further described in detail below in combination with the drawings and examples.

[0032] Method embodiment:

[0033] The device mainly includes a mechanical brake switch, a brake pedal angle voltage sensor, a throttle pedal voltage sensor, and a vehicle controller, wherein the vehicle controller receives the brake switch state, the brake pedal voltage value, and the throttle pedal voltage value through a hard wire. The vehicle controller determines the driver's action of stepping on the brake pedal according to the brake switch signal state, and determines the depth of the driver's stepping on the brake pedal according to the angle sensor voltage value.

[0034] The vehicle controller first diagnoses the brake switch according to the input brake pedal signal and throttle pedal signal to determine whether the brake switch is invalid. If the brake switch signal is invalid, the vehicle controller will not use the signal, and the opening degree calculated by the brake voltage value will be used instead of the brake switch signal. If the brake switch is not invalid, the brake switch signal is used for entry and exit control. The vehicle controller determines whether the vehicle enters the brake mode according to the brake switch state and the brake opening size after the above diagnosis, and uses the brake opening to calculate the feedback torque in the brake mode. This embodiment takes a new energy vehicle as an example to introduce the whole implementation process of the technical scheme.

[0035] The flowchart of the method is shown in Figure 1 The method includes the following steps:

[0036] Step 1, after the driver steps on the brake and powers on, the brake pedal angle sensor voltage is obtained, and it is judged whether the brake pedal opening is greater than A1; if the brake pedal opening is greater than A1, the brake is effective, and the vehicle controller controls the vehicle to enter the brake mode, at this time no driving torque is output; if the brake pedal opening is less than or equal to A1, step 2 is executed.

[0037] Wherein, the brake pedal opening calculation formula is as follows:

[0038]

[0039] In the formula, U0 is the zero voltage, U max is the maximum voltage of the brake pedal, U is the actual voltage value of the brake pedal angle sensor, and a is the brake pedal opening.

[0040] Step 2, it is judged whether the throttle pedal state, if the throttle pedal opening is greater than A3, the driver steps on the throttle pedal, and the vehicle exits the brake mode; if the throttle pedal opening is less than or equal to A3, step 3 is executed.

[0041] Wherein, the throttle switch signal is judged as follows: if the throttle pedal voltage value is greater than A3, the throttle switch is effective, otherwise it is not effective.

[0042] Step 3, it is judged whether the brake switch signal is effective, as shown in Figure 2 ; if the brake switch signal is not effective, the brake is not effective, and the vehicle exits the brake; if the brake switch signal is effective, the brake is effective.

[0043] Wherein, the method for judging whether the brake switch signal is effective is: after the vehicle is successfully powered on, the driver releases the brake pedal and the throttle pedal, if the mechanical brake switch is not failed, it indicates that the mechanical brake switch is in a non-fault state and can express the brake switch signal, further judging whether the mechanical brake switch is effective, wherein the mechanical brake switch effective and ineffective indicate two states of the mechanical brake switch, the mechanical brake switch ineffective indicates that the mechanical brake switch is opened, and the mechanical brake switch effective indicates that the mechanical brake switch is closed, if the mechanical brake switch is effective, the mechanical brake switch signal is effective, if the mechanical brake switch is ineffective, the mechanical brake switch signal is ineffective; if the mechanical brake switch has failed, it indicates that the mechanical brake switch is in a fault state and cannot express the brake switch signal, which needs to be further judged whether the brake switch signal is effective according to the brake pedal opening. If the brake pedal opening is greater than A2, the brake switch signal is effective, if the brake pedal opening is less than A2, the brake switch signal is ineffective, and the next cycle detection is entered.

[0044] The mechanical brake switch failure judgment is mainly based on the accelerator pedal switch signal, the brake pedal opening, the mechanical brake switch state, including the mechanical brake switch normally closed failure and the mechanical brake switch normally open failure. When the mechanical brake switch state is continuously valid for more than T1 time and the accelerator switch signal experiences a change from invalid to valid in the time, the mechanical brake switch normally closed failure is judged. When the mechanical brake switch state is continuously switched from valid to invalid for more than N times, the mechanical brake switch normally closed failure judgment is exited. When the brake pedal opening is continuously greater than A4 for T2 time and the mechanical brake switch is invalid, the mechanical brake switch normally open failure is considered. If the mechanical brake switch is continuously switched from invalid to valid for more than N times, the mechanical brake switch normally open failure judgment is removed.

[0045] The parameters A1, A2, A3, A4, T1, T2, N, U0 and Umax need to be matched and calibrated according to the specific vehicle system.

[0046] The method judges whether the current brake switch signal is valid. If the current mechanical brake switch is invalid, the brake switch signal is acquired through the brake pedal opening, so that the corresponding judgment is performed, thereby ensuring the acquisition of the brake switch signal when the mechanical brake switch signal is invalid, and improving the performance of the vehicle.

[0047] System embodiment:

[0048] The vehicle brake control system of the application comprises a control module and an acquisition module. The acquisition module is used to acquire the brake pedal opening and the accelerator pedal opening, and is connected with the control module. The control module is used to realize the vehicle brake control method introduced in the method embodiment of the application. The method has been described in detail in the method embodiment, and will not be described here.

[0049] Vehicle embodiment:

[0050] The vehicle of the embodiment comprises the vehicle brake control system introduced in the system embodiment. The vehicle using the vehicle brake control system of the application can better complete the judgment of whether the vehicle enters the brake mode, and improves the reliability of the vehicle. The system has been described in detail in the above embodiment, and will not be described here.

Claims

1. A vehicle brake control method characterized by, When the vehicle is powered on, if the brake pedal opening degree is less than or equal to a first preset threshold value and the accelerator pedal opening degree is less than or equal to a third preset threshold value, it is determined whether the vehicle enters a brake mode according to a brake switch signal: if the brake switch signal is valid, the vehicle enters the brake mode; if the brake switch signal is invalid, the vehicle does not enter the brake mode. When the vehicle is powered on and the brake pedal and the accelerator pedal are depressed, if the mechanical brake switch is not invalid and the mechanical brake switch is valid, or the mechanical brake switch is invalid and the brake pedal opening degree signal is greater than a second preset threshold value, it is determined that the brake switch signal is valid; otherwise, it is determined that the brake switch signal is invalid, wherein the invalidity and the validity of the mechanical brake switch are used to represent whether the mechanical brake switch is faulty, and the state of the mechanical brake switch is used to represent the state of the mechanical brake switch. The invalidity of the mechanical brake switch includes a normally closed invalidity and a normally open invalidity of the mechanical brake switch; when the state of the mechanical brake switch is continuously valid for more than a first preset time and the accelerator switch signal experiences a change from invalid to valid within the time, it is determined that the mechanical brake switch is normally closed; when the brake pedal opening degree is greater than a fourth preset threshold value for more than a second preset time and the mechanical brake switch is always invalid, it is determined that the mechanical brake switch is normally open.

2. The vehicle brake control method according to claim 1, characterized by, The calculation formula of the brake pedal opening degree is: Wherein, U0 is the zero voltage, U max is the maximum voltage of the brake pedal, U is the actual voltage value of the brake pedal angle sensor, and a is the brake pedal opening degree.

3. The vehicle brake control method according to claim 1, characterized by, The determination method of whether the accelerator switch signal is valid is: if the accelerator pedal opening degree is greater than a third preset threshold value, the accelerator switch signal is valid; otherwise, the accelerator switch signal is invalid.

4. The vehicle brake control method according to claim 1, characterized by If the brake pedal opening degree is greater than the first preset threshold value, the vehicle enters the brake mode.

5. The vehicle brake control method according to claim 1, characterized by If the brake pedal opening degree is less than or equal to the first preset threshold value and the accelerator pedal opening degree is greater than the third preset threshold value, the brake is invalid, and the vehicle does not enter the brake mode.

6. The vehicle brake control method according to claim 1, characterized by When the mechanical brake switch is switched from valid to invalid for multiple times in succession, the normally closed invalidity determination of the mechanical brake switch is exited; when the mechanical brake switch is switched from invalid to valid for multiple times in succession, the normally open invalidity determination of the mechanical brake switch is exited.

7. A vehicle brake control system characterized by comprising: The vehicle brake control system comprises a control module and a collection module, the collection module is used to acquire the brake pedal opening degree and the accelerator pedal opening degree, and is connected with the control module to send the acquired data to the control module, and the control module is used to execute computer program instructions to realize the vehicle brake control method according to any one of claims 1-6.

8. A vehicle characterized by comprising: The vehicle brake control system according to claim 7.

Images