阅读说明：本技术 电动车急刹车控制方法及存储介质 (Emergency brake control method for electric vehicle and storage medium ) 是由 陶志鹏 胡敬伟 李建军 郑春阳 于 2020-05-12 设计创作，主要内容包括：本发明公开一种电动车急刹车控制方法及存储介质。它包括获取刹车起始时刻第一电机转速n<Sub>0</Sub>,基于第一电机转速n<Sub>0</Sub>判断车辆的急刹车控制模式；当第一电机转速n<Sub>0</Sub>不大于设定第一电机转速,实施低速急刹车控制模式；在低速急刹车过程中,获取电机转速开始反转到设定的第二电机转速n<Sub>2</Sub>的第一时间T<Sub>1</Sub>,当第一时间T<Sub>1</Sub>不大于第一设定时间T<Sub>0</Sub>,确定低速急刹车有效标记,禁止电机进入驻坡控制模式。本发明的上述技术方案,采用对车辆急刹车状态进行分类管理控制,通过识别判断确定不同的急刹车状态,实施不同的急刹车控制模式,禁止电机进入驻坡控制模式。从而避免了急刹车时,错误实施驻坡控制模式。(The invention discloses an electric vehicle emergency brake control method and a storage medium. It includes obtaining the first motor speed n at the starting moment of braking 0 Based on the first motor speed n 0 Judging an emergency braking control mode of the vehicle; when the first motor rotates at a speed n 0 The rotating speed of the first motor is not greater than the set rotating speed, and a low-speed and quick-braking control mode is implemented; in the process of low-speed sudden braking, the rotating speed of the motor is acquired and begins to be reversed to a set second rotating speed n of the motor 2 First time T of 1 When the first time T 1 Is not more than the first set time T 0 And determining a low-speed emergency brake effective mark and forbidding the motor to enter a hill-holding control mode. According to the technical scheme, the vehicle emergency braking states are subjected to classified management control, different emergency braking states are determined through recognition and judgment, and different emergency braking is implementedAnd in the control mode, the motor is prohibited from entering the hill-holding control mode. Therefore, the situation that the hill-holding control mode is wrongly implemented when sudden braking is carried out is avoided.)

1. A method for controlling emergency braking of electric vehicle includes obtaining the rotation speed of the first motor at the beginning of braking₀) Based on the first motor speed (n)₀) Judging the sudden braking control mode of the vehicle when the first motor speed (n)₀) If the rotating speed of the motor is greater than the first set rotating speed, implementing a high-speed emergency braking control mode; when the first motor speed (n)₀) The rotating speed of the first motor is not greater than the set rotating speed, and a low-speed and quick-braking control mode is implemented;

the low-speed emergency braking control mode comprises the following steps of acquiring the rotating speed of the motor to start reversing to a set second rotating speed (n) of the motor in the low-speed emergency braking process₂) First time (T)₁) When a first time (T)₁) Not more than a first set time (T)₀) And determining a low-speed emergency brake effective mark and forbidding the motor to enter a hill-holding control mode.

2. The sudden braking control method of an electric vehicle as claimed in claim 1, wherein the second motor rotation speed (n) is set in a low-speed sudden braking control mode₂) Is the motor speed of the vehicle in a forward state and/or the motor speed of the vehicle in a reverse state.

3. The sudden braking control method for the electric vehicle as claimed in claim 1 or 2, wherein in the low speed sudden braking control mode, after the low speed sudden braking valid flag is determined, the duration is less than a second time threshold, and the motor is prohibited from entering the hill-holding control mode.

4. The method as claimed in claim 1, wherein the high-speed sudden braking control mode includes obtaining a deceleration rate (a) of the motor during the high-speed sudden braking operation time, determining whether the vehicle is in a high-speed sudden braking state based on the deceleration rate (a) of the motor, determining a high-speed sudden braking flag, and prohibiting the motor from entering the hill-holding control mode.

5. The method as claimed in claim 4, wherein the motor is prohibited from entering the hill-holding control mode when the duration is less than the third time threshold after the high-speed sudden braking effective flag is determined.

6. The sudden braking control method of an electric vehicle according to claim 4 or 5, wherein the deceleration rate (a) is not less than the set deceleration rate (a)₀) And determining the high-speed emergency brake effective mark.

7. The method as claimed in claim 1, wherein the low-speed sudden braking control mode further comprises obtaining gear information at a first time and gear information at a second time during the low-speed sudden braking action time, determining whether the gear is changed, and implementing the low-speed sudden braking shift control mode.

8. The electric vehicle hard brake control method of claim 7, wherein implementing the low speed hard brake shift control mode comprises obtaining a third motor speed (n) at a second time₁) (ii) a Third Motor speed (n)₁) Greater than a set third motor speed (n)₃) And determining a low-speed emergency brake gear shifting mark and prohibiting the motor from entering a hill-holding control mode.

9. The electric vehicle hard brake control method as claimed in claim 8, wherein after determining the low speed hard brake shift flag, the duration is less than a fourth time threshold, and the motor is prohibited from entering the hill hold control mode.

10. A storage medium comprising instructions for execution which, when processed by data processing apparatus, cause the data processing apparatus to perform a method of controlling sudden braking of an electric vehicle as claimed in any one of claims 1 to 9.

Technical Field

The invention belongs to the electric vehicle control technology, and particularly relates to an electric vehicle emergency brake control technology.

Background

The electric vehicle realizes the function of slope stopping through the motor under the condition that the inclination angle sensor is not installed, and the control principle is that the motor is controlled to continuously block rotation after the rotating speed of the motor is judged to start to rotate reversely according to gears, and reverse torque is applied. Until the vehicle stops, the aim of parking on the slope is achieved. This control strategy is good for achieving parking control of an electric vehicle on a hill. However, there is a risk of malfunction due to motor speed control. The vehicle can have the possibility of motor speed reversal after the emergency braking parks when the open road is gone, perhaps the vehicle fast switch over gear causes the current rotational speed of motor in short-term and current gear mismatch after the emergency braking speed reduction, and then arouses the vehicle mistake to get into on the open road and stay the slope mode, reduces vehicle driving comfort level, can cause the vehicle to last shake potential safety hazard out of control even. The risk of mistakenly entering a hill-holding mode under the condition of sudden braking during the running of the vehicle on a flat road is avoided. Therefore, the vehicle needs to recognize the driving state of the vehicle during driving and perform accurate control on the vehicle driving on a flat road.

The device and the method for judging the emergency degree of braking disclosed in CN100509514C are used for judging the emergency degree of braking by detecting the time difference of different positions of the brake pedal in the process of stepping on the brake pedal, and the method cannot truly reflect the condition of the rotating speed of the motor in the braking process. The control of the vehicle brake mode cannot be realized.

Disclosure of Invention

The invention aims to provide an emergency brake control method and a storage medium for an electric vehicle, which are used for implementing different emergency brake control modes after identifying that the vehicle is in an emergency brake state, and avoiding the vehicle from entering a parking control mode by mistake during emergency braking.

One of the technical schemes of the invention is as follows: the emergency brake control method for the electric vehicle comprises the steps of obtaining the rotating speed n of a first motor at the starting moment of braking₀Based on the first motor speed n₀Judging the emergency braking control mode of the vehicle when the rotating speed n of the first motor is₀If the rotating speed of the motor is greater than the first set rotating speed, implementing a high-speed emergency braking control mode; when the first motor rotatesSpeed n₀The rotating speed of the first motor is not greater than the set rotating speed, and a low-speed and quick-braking control mode is implemented;

the low-speed emergency braking control mode comprises the following steps of acquiring the rotating speed of the motor to start reversing to a set second rotating speed n of the motor in the low-speed emergency braking process₂First time T of₁When the first time T₁Is not more than the first set time T₀And determining a low-speed emergency brake effective mark and forbidding the motor to enter a hill-holding control mode.

In the process of sudden braking of the electric vehicle, the driving motor can be overturned under the action of inertia, so that the controller MCU wrongly executes a slope-stopping working mode, and the motor is locked to generate jitter. According to the technical scheme, the vehicle sudden braking states are subjected to classified management control, different sudden braking states are determined through recognition and judgment, different sudden braking control modes are implemented, and the motor is forbidden to enter the hill-holding control mode. Therefore, the situation that the hill-holding control mode is wrongly implemented when sudden braking is carried out is avoided.

The further optimized technical scheme is as follows: in the low speed sudden braking control mode, the second motor speed (n2) is a motor speed of the vehicle in a forward state and/or a motor speed of the vehicle in a reverse state. The characteristic ensures that the problem of sudden braking and mistakenly implementing the hill-holding control mode can be solved when the vehicle runs forward or backs up and suddenly stops.

The further optimized technical scheme is as follows: and in the low-speed and quick-braking control mode, after the low-speed and quick-braking effective mark is determined, the duration is less than a second time threshold, and the motor is forbidden to enter the hill-holding control mode.

After the low-speed and quick-braking control mode is implemented for a period of time, the process is ensured to be completely stable, and then the low-speed and quick-braking effective mark is released.

The further optimized technical scheme is as follows: the high-speed emergency brake control mode comprises the steps of obtaining the deceleration and acceleration (a) of the motor within the action time of the high-speed emergency brake, judging whether the vehicle is in a high-speed emergency brake state or not based on the deceleration and acceleration (a) of the motor, determining an effective high-speed emergency brake mark, and forbidding the motor to enter the hill-holding control mode.

Based on the change rate of the speed of the motor rotating speed in time, the state of high-speed emergency braking of the vehicle is truly reflected, and the risk of identifying the state of inaccurate high-speed emergency braking in the prior art is avoided. After the high-speed emergency brake is confirmed to be effective, the motor is forbidden to enter a hill-holding control mode, the high-speed emergency brake priority level control is implemented, and the safety of the high-speed emergency brake is ensured.

The further optimized technical scheme is as follows: and after the high-speed sudden braking mark is determined, prohibiting the motor from entering a hill-holding control mode when the duration is less than a third time threshold.

After the high-speed emergency brake control mode is implemented for a period of time, the high-speed emergency brake effective mark is released after the process is ensured to be completely stable.

The further optimized technical scheme is as follows: the deceleration rate (a) is not less than the set deceleration rate (a)₀) And determining the high-speed emergency brake effective mark.

The further optimized technical scheme is as follows: the low-speed emergency brake control mode further comprises the step of judging whether the gear is changed or not and implementing the low-speed emergency brake gear-shifting control mode in the low-speed emergency brake action time by acquiring the gear information at the first moment and the gear information at the second moment.

The further optimized technical scheme is as follows: implementing the low-speed hard-braking shift control mode includes obtaining a third motor speed (n) at a second time₁) (ii) a Third Motor speed (n)₁) Greater than a set third motor speed (n)₃) And determining a low-speed emergency brake gear shifting mark and prohibiting the motor from entering a hill-holding control mode.

The further optimized technical scheme is as follows: and after the low-speed sudden braking gear shifting mark is determined, the duration is less than a fourth time threshold, and the motor is forbidden to enter a hill-holding control mode.

Under the control mode of low-speed emergency braking, the control mode of low-speed emergency braking gear shifting is also added, the stability of the gear shifting process is realized, and the process controller is prevented from executing the hill-holding control mode by mistake.

The logic algorithm process of the scheme of the invention is simple, and no hardware is added. And realizing accurate control of the driving state.

The second technical scheme of the invention is as follows: a storage medium comprises execution instructions, and when the execution instructions are processed by a data processing device, the data processing device executes the electric vehicle emergency brake control method.

Drawings

FIG. 1 is a logic flow diagram of the method of the present invention.

FIG. 2 control pattern for low speed hard brake shifting

Detailed Description

The following detailed description is provided for the purpose of explaining the claimed embodiments of the present invention so that those skilled in the art can understand the claims. The scope of the invention is not limited to the following specific implementation configurations. It is intended that the scope of the invention be determined by those skilled in the art from the following detailed description, which includes claims that are directed to this invention.

The control method is realized by a storage medium, a data processing device is realized based on a motor controller MCU, and the obtained various data are realized by the motor controller MCU; of course, the method software of the present invention may also be implemented in the vehicle control unit.

The MCU acquires a hand brake signal, a foot brake signal, an accelerator pedal signal and a gear signal of the whole vehicle in real time through a power CAN bus of the whole vehicle, operates the driving motor according to the instruction of a current control system of the whole vehicle, and simultaneously feeds back the operation state of a driving motor system to the power CAN bus of the whole vehicle in real time; the MCU judges the emergency brake according to the motor rotor position information and the current vehicle running state information detected in real time;

the motor controller MCU judges whether the vehicle is in an emergency brake state according to vehicle information and driving motor rotor position information collected in real time; according to the emergency brake judging method, the whole vehicle information acquired in real time is analyzed, and data processing is performed on the emergency brake working condition of the vehicle to obtain the requirement, wherein the requirement comprises high-speed emergency brake judgment, low-speed emergency brake judgment, emergency brake gear shifting judgment and emergency brake holding time.

As shown in fig. 1, when the vehicle is normally running, the driver performs a braking action, and the braking action includes the whole process of depressing the brake pedal and releasing the brake pedal. Treading a brake pedal to generate a brake rising edge signal; and releasing the lower brake pedal to generate a brake falling edge signal.

Obtaining the first motor rotating speed n at the moment when the brake pedal is stepped on₀And a shift position signal G1, and start timing;

comparing the first motor speed n₀And a first set motor speed n; the first set motor speed n may be set according to the vehicle, and in the embodiment, the first set motor speed is 1000 rpm.

When | n₀|<And (5) entering a low-speed emergency braking control mode at 1000 rpm:

in the process of low-speed sudden braking, the motor rotation speed is acquired and obtained, the motor rotation speed is acquired and started to be reversed to a set second motor rotation speed n₂First time T of₁Namely, when the vehicle brakes suddenly, the motor is dragged reversely due to the inertia effect. Set second motor speed n₂Setting according to the vehicle type; including the motor speed of the vehicle in a forward state and/or the motor speed of the vehicle in a reverse state.

The threshold value of the second motor speed n2 when the motor is dragged in the reverse direction or in the forward direction can be the same or different. In the embodiment, when the vehicle is in a forward state, the motor is reversely rotated, namely the motor is dragged in a reverse direction at the second motor rotating speed n₂The threshold was-20 rpm; when the vehicle is in a reverse state, the motor rotates reversely, namely the motor is dragged forwards at a second motor rotating speed n₂The threshold was +20 rpm. A first set time T₀Setting according to vehicle type, and setting the first set time T when the motor is dragged in reverse direction or forward direction₀The threshold values may be the same or different; in the embodiment, the first set time T₀0.02 second, the setting is the rate of change of the motor speed reversal, the change of the motor speed is rapidly identified, the low-speed and quick-braking effective mark is rapidly determined, and the response speed is improved.

Obtaining the rotation speed n of the second motor which is reversed to the set rotation speed₂First time T of₁That is, when the gear is D gear, the time of the actual rotating speed from 0 to-20 rpm is recorded, or when the gear is R gear, the time of the actual rotating speed from 0 to +20rpm is recorded(ii) a When the first time T₁And when the time is not more than 0.02 second, determining a low-speed and quick-braking effective mark, and forbidding the motor to enter a hill-holding control mode. Specifically, after the low-speed and quick-braking effective mark is determined, the duration is less than a second time threshold value, and the motor is forbidden to enter the hill-holding control mode. In the embodiment the second time threshold is 2 seconds.

When | n₀|>1000rpm, entering a high-speed emergency brake control mode:

in the process of high-speed emergency braking, obtaining a braking time, wherein in the embodiment, the time when a brake pedal is stepped down (a brake rising edge signal) starts to time; stopping timing at the moment of pedal release (brake falling edge signal), and recording brake time T₀And simultaneously acquiring the motor speed n at the moment of pedal release (brake falling edge signal)₂.

Deceleration rate a (rpm/s) of the motor in the high-speed quick braking action time, wherein a is (| n)₀-n₂|)/T₀；

The deceleration rate a is not less than the set deceleration rate a₀And determining the high-speed emergency brake effective mark. Set deceleration rate a₀Is set according to the vehicle, the deceleration and acceleration a set in the embodiment₀The threshold value of (2) is 1000 rpm/s.

And when the a is more than 1000rpm/s, determining a high-speed emergency brake valid mark, and forbidding the motor to enter the hill-holding control mode, and particularly, after the high-speed emergency brake valid mark is determined, forbidding the motor to enter the hill-holding control mode when the duration is less than a third time threshold. In the embodiment the second time threshold is 2 seconds.

Through recording and analyzing the rotating speed value and the gear signal when the brake is stepped and released at each time and the time of the brake action vehicle, the mistaken entering into the hill-holding mode caused by rapid gear shifting when the vehicle is stepped on the flat road can be avoided, and the driving smoothness of the vehicle is improved.

As shown in fig. 2, in the low-speed and sudden-braking control mode, the gear information at the first moment and the gear information at the second moment within the low-speed and sudden-braking action time are acquired, whether the gear is changed is judged, and the low-speed and sudden-braking gear-shifting control mode is implemented; obtaining the third motor speed n at the second moment₁(ii) a Third electricityMachine speed n₁Is greater than the set third motor speed n₃And determining a low-speed emergency brake gear shifting mark and prohibiting the motor from entering a hill-holding control mode.