An emergency braking control method and system for electric vehicles

Abstract

This invention discloses an emergency braking control method and system for electric vehicles, primarily relating to the field of electric vehicle braking technology. It includes acquiring the status information of a combination switch; acquiring the status information of the brake pedal and accelerator pedal; acquiring the basic status information of the power battery; acquiring the status information of the drive motor and drive motor controller; and calculating the feedback torque based on the acquired status information. The beneficial effect of this invention is that it can significantly reduce the occurrence of traffic accidents caused by insufficient emergency braking distance or mistaking the accelerator pedal for the brake pedal.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle braking technology, specifically to an emergency braking control method and system for electric vehicles. Background Technology

[0002] Energy recovery braking has become a common technology in electric vehicles. When the accelerator pedal is released, the vehicle decelerates at a rate greater than the natural decay rate. However, if this mode is used and relied upon for a long time, the accelerator pedal may be mistaken for the brake pedal during emergency braking, leading to traffic accidents.

[0003] In addition, if the energy feedback is turned off or at a low level while driving, relying solely on the brake pedal for emergency braking may result in an excessively long braking distance, potentially leading to a traffic accident.

[0004] Therefore, a new braking method for electric vehicles is urgently needed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an emergency braking control method and system for electric vehicles, which can greatly reduce the occurrence of traffic accidents caused by insufficient emergency braking distance or mistaking the accelerator pedal for the brake pedal.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] An emergency braking control method for an electric vehicle includes the following steps: acquiring the status information of a combination switch; acquiring the status information of the brake pedal and accelerator pedal; acquiring the basic status information of the power battery; acquiring the status information of the drive motor and drive motor controller; and calculating the feedback torque based on the acquired status information.

[0008] Preferably, the acquisition of the status information of the combination switch specifically involves: obtaining the status of the combination switch and determining the current energy recovery level through hard wiring or CAN signal.

[0009] Preferably, determining the current energy recovery level specifically involves: acquiring and recording the current energy recovery level; when the combination switch is in a predetermined state and the energy recovery level is not the highest state, setting the energy recovery level to the highest level; when the combination switch changes from the predetermined state to a non-predetermined state, restoring the energy feedback level to the initial setting.

[0010] Preferably, collecting the status information of the brake pedal and accelerator pedal specifically involves: obtaining the current status of the accelerator pedal and brake pedal, and when the combination switch is in a predetermined state, setting the accelerator pedal validity to invalid.

[0011] Preferably, the basic state information of the power battery collected specifically includes: total voltage, cell temperature, SOC, and fault status information.

[0012] Preferably, the calculation of the feedback torque includes the following steps: calculating braking feedback; calculating coasting feedback; calculating energy recovery capability, and determining the overall vehicle status.

[0013] Preferably, the calculation of brake feedback specifically involves: calculating the brake torque required by the driver based on the brake pedal position and the maximum allowable brake torque of the motor; obtaining the maximum allowable brake torque of the entire vehicle based on the motor speed; and taking the smaller of the two values ​​to finally obtain the motor brake feedback torque.

[0014] Preferably, the calculation of coasting feedback specifically involves: simulating the towing torque of a whole vehicle based on the motor speed; determining the maximum allowable reverse towing torque of the whole vehicle based on the motor speed; and taking the smaller of the two values ​​to finally obtain the motor coasting feedback torque.

[0015] Preferably, the calculation of energy recovery capability and determination of vehicle status specifically involves: acquiring basic information about the current vehicle operation, including vehicle speed, total voltage of the power battery, maximum voltage of individual cells, current SOC, minimum temperature of individual cells, power battery system fault level, electric drive system temperature, electric drive system fault level, and vehicle fault level. When the combination switch is in a predetermined state, the vehicle status is comprehensively judged to enable the electric drive system to perform the highest level of energy feedback to brake the vehicle.

[0016] An emergency braking control system for an electric vehicle includes an information acquisition module, a data processing module, and a data output module. The information acquisition module is data-connected to the data processing module, and the data processing module is data-connected to the data output module. The information acquisition module is used to acquire the status information of the combination switch, the status information of the brake pedal and the accelerator pedal, the basic status information of the power battery, and the status information of the drive motor and the drive motor controller. The data processing module is used to calculate the feedback torque, and the data output module is used to output the feedback torque.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The implementation of this invention will greatly reduce the occurrence of traffic accidents caused by insufficient emergency braking distance or mistaking the accelerator pedal for the brake pedal. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method of the present invention.

[0020] Figure 2 This is a schematic diagram of the device connection of the present invention.

[0021] Figure 3 This is the method logic diagram of the present invention.

[0022] The labels shown in the attached diagram:

[0023] 1. First multi-function switch; 2. Second multi-function switch; 3. Brake pedal; 4. Power battery system; 5. Electric drive system; 6. Vehicle controller; 7. Accelerator pedal. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0025] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.

[0026] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0027] Example: An emergency braking control method for electric vehicles

[0028] like Figure 1 As shown, it includes the following steps:

[0029] S1: Collect the status information of the combination switch, specifically: obtain the status of the combination switch through hard wire or CAN signal and determine the current energy recovery level. Specifically, the determination of the current energy recovery level is as follows: obtain and record the current energy recovery level. When the combination switch is in a predetermined state and the energy recovery level is not the highest state, set the energy recovery level to the highest level. When the combination switch changes from the predetermined state to a non-predetermined state, the energy recovery level is restored to the initial setting.

[0030] S2: Collect the status information of the brake pedal and accelerator pedal, specifically: obtain the current status of the accelerator pedal and brake pedal, and when the combination switch is in a predetermined state, set the accelerator pedal validity to invalid;

[0031] S3: Collects basic status information of the power battery, including: total voltage, single cell temperature, SOC and fault status information;

[0032] S4: Collect status information of the drive motor and drive motor controller;

[0033] S5: Calculate the feedback torque based on the status information collected in steps S1-S4. The calculation of the feedback torque includes the following steps:

[0034] S51: Calculate braking feedback:

[0035] When the driver presses the brake pedal, the controller calculates the required braking torque based on the brake pedal position (generally 0% to 100%) and the maximum permissible braking torque of the motor. At the same time, it calculates the maximum permissible regenerative power of the battery based on the battery's SOC, voltage, temperature, current, maximum permissible regenerative current, and battery management system faults (if there is a fault, the maximum permissible regenerative power is generally reduced proportionally). It is necessary to ensure that the regenerative power of the entire vehicle does not exceed the maximum permissible regenerative power of the battery. The maximum permissible braking torque of the entire vehicle is obtained based on the motor speed. The smaller of the two values ​​is taken to obtain the final motor braking regenerative torque.

[0036] Overall description: The main logic of this strategy is to calculate the braking torque based on the driver's brake pedal opening and the vehicle's state in order to meet the energy feedback requirements during vehicle braking;

[0037] S52: Calculate glide feedback:

[0038] Electric vehicle coasting feedback strategy: When the driver releases the accelerator pedal and does not press the brake pedal, the vehicle controller simulates a towing torque of the entire vehicle based on the motor speed. It calculates the maximum allowable feedback power of the battery based on the maximum charging current and voltage of the battery system and battery management system faults, so as to ensure that the feedback power of the entire vehicle does not exceed the maximum allowable feedback power of the battery. The maximum allowable reverse towing torque of the entire vehicle is obtained based on the motor speed. The smaller value of the two is finally obtained as the motor coasting feedback torque.

[0039] Overall description: The main function of this strategy is to calculate the coasting torque based on the vehicle's state in order to meet the energy feedback requirements of the vehicle during coasting.

[0040] S53: Calculate energy recovery capability and determine vehicle status.

[0041] The overall vehicle status is generally considered in terms of battery MAP. The maximum allowable regenerative current of the battery is determined based on the current battery temperature, individual cell voltage, and SOC. The maximum allowable regenerative current and the total battery voltage determine the current maximum allowable regenerative power of the battery. If the power battery is fault-free or has a fault that does not affect regenerative power, the allowable regenerative power is calculated normally. If the battery system has a fault that limits regenerative power, the allowable regenerative power needs to be proportionally limited in the calculated value according to the fault handling mechanism. If the battery system has a fault that does not allow regenerative power or requires high voltage, the regenerative power is 0. In addition, the presence of faults in other high-voltage components should also be considered, such as whether the electric drive system has faults that limit regenerative power, do not allow regenerative power, or require high voltage. The fault handling mechanism is similar.

Claims

1. An emergency braking control method for an electric vehicle, characterized in that, Includes the following steps: S1: Collect status information of the combination switch; S2: Collect status information of the brake pedal and accelerator pedal; S3: Collect basic status information of the power battery; S4: Collect status information of the drive motor and drive motor controller; S5: Calculate the feedback torque based on the status information collected in steps S1-S4; The specific method for acquiring the status information of the combination switch is to obtain the status of the combination switch and determine the current energy recovery level through hard wire or CAN signal; The specific steps for determining the current energy recovery level are as follows: acquire and record the current energy recovery level; when the combination switch is in a predetermined state and the energy recovery level is not the highest state, set the energy recovery level to the highest level; when the combination switch changes from the predetermined state to a non-predetermined state, restore the energy recovery level to the initial setting. The specific steps for collecting the status information of the brake pedal and accelerator pedal are as follows: obtain the current status of the accelerator pedal and brake pedal, and when the combination switch is in a predetermined state, set the accelerator pedal validity to invalid; The calculation of the feedback torque includes the following steps: S51: Calculate braking feedback; S52: Calculates glide feedback; S53: Calculate energy recovery capability and determine the overall vehicle status; The calculation of energy recovery capability and determination of the vehicle status specifically involves: acquiring the current basic information of the vehicle operation, including vehicle speed, total voltage of the power battery, maximum voltage of a single cell, current SOC, minimum temperature of a single cell, power battery system fault level, electric drive system temperature, electric drive system fault level, and vehicle fault level; when the combination switch is in a predetermined state, comprehensively judging the vehicle status, enabling the electric drive system to perform the highest level of energy feedback to brake the vehicle.

2. The emergency braking control method for an electric vehicle according to claim 1, characterized in that, The basic state information of the power battery collected specifically includes: total voltage, cell temperature, SOC, and fault status information.

3. The emergency braking control method for an electric vehicle according to claim 1, characterized in that, The calculation of brake feedback specifically involves: calculating the brake torque required by the driver based on the brake pedal position and the maximum allowable braking torque of the motor; determining the maximum allowable braking torque of the entire vehicle based on the motor speed; and finally obtaining the motor brake feedback torque by taking the smaller of the two values.

4. The emergency braking control method for an electric vehicle according to claim 1, characterized in that, The calculation of coasting feedback specifically involves: simulating the towing torque of a whole vehicle based on the motor speed; determining the maximum allowable reverse towing torque of the whole vehicle based on the motor speed; and taking the smaller of the two values ​​to finally obtain the motor coasting feedback torque.

5. An emergency braking control system for an electric vehicle, used to implement the emergency braking control method for an electric vehicle as described in claim 1, characterized in that, It includes an information acquisition module, a data processing module, and a data output module. The information acquisition module is data-connected to the data processing module, and the data processing module is data-connected to the data output module. The information acquisition module is used to acquire the status information of the combination switch, the status information of the brake pedal and accelerator pedal, the basic status information of the power battery, and the status information of the drive motor and drive motor controller. The data processing module is used to calculate the feedback torque, and the data output module is used to output the feedback torque.

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