CN113954645B - Adaptive Cruise Control Feedback Braking Torque Monitoring Method for Electric Vehicles - Google Patents

Abstract

The present invention provides an adaptive cruise control feedback braking torque monitoring method for electric vehicles. The method includes: when the vehicle enters the adaptive cruise control state, real-time monitoring of the actual motor feedback braking torque and the current vehicle speed ; When the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the first threshold, and the integral value in the first preset time period exceeds the second threshold, it is considered that the motor feedback braking is not enough Let the whole vehicle achieve a reasonable deceleration, and the vehicle stability control system enters the pre-filling stage; when the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the third threshold, and within the second preset time period If the integral value exceeds the fourth threshold, it is determined that the vehicle stability control system needs to provide hydraulic braking.

Description

Adaptive Cruise Control Feedback Braking Torque Monitoring Method for Electric Vehicles

technical field

The invention relates to the field of adaptive cruise control of electric vehicles.

Background technique

The electrification of automobiles is developing in depth, and the focus of competition in the future automobile market will be the intelligence and networking of electric vehicles. Adaptive cruise control (ACC) is the most important function of electric vehicles as intelligent. Its safety design has attracted the attention of automobile R&D engineers, especially the safety design of the vehicle's self-acceleration and deceleration process in the process of following the target after identifying the target. However, during the deceleration process, the vehicle stability control system (ESC) and the motor participate in the braking of the whole vehicle at the same time. The ESC brakes the wheels directly through the braking hydraulic pressure, and the motor decelerates and brakes through feedback power generation. If the driver assistance controller (ADAS) does not participate in the monitoring of the braking torque of the vehicle and the feedback torque of the motor during the entire deceleration process, it will easily cause safety hazards. However, in the prior art, during the ACC deceleration process, the deceleration of the whole vehicle is realized only through ESC braking, without monitoring the feedback torque of the motor.

Therefore, it is urgent to provide a torque safety monitoring method to prevent potential safety hazards caused by motor feedback torque out of control and play an important role in ensuring safe driving of the vehicle.

Contents of the invention

In order to overcome the defects of the prior art, the present invention provides an ACC feedback braking torque monitoring method for electric vehicles, which is used for real-time monitoring of the motor output negative torque during ACC feedback braking, vehicle deceleration, and accelerator pedal opening , the vehicle speed changes, when it is detected that the braking torque requested by ACC is inconsistent, the monitoring system requests ESC to intervene in hydraulic braking after the error integral value exceeds a certain threshold within a certain period of time; or it detects that the deceleration requested by ACC is different from the current adjustment When the deceleration of the vehicle is inconsistent, the monitoring system requests ESC to intervene in hydraulic braking after the error integral value exceeds a certain threshold within a certain period of time; or when it detects that the deceleration requested by ACC is inconsistent with the current If the integral value of the error exceeds a certain threshold and the acceleration requested by ACC is inconsistent with the current acceleration of the vehicle when the accelerator is not stepped on, the integral value of the error within a certain period of time exceeds a certain threshold, which means that the motor feedback braking under the condition of ACC Whether it is driving or driving, it cannot meet the driving needs of the whole vehicle, and the monitoring system requests to turn off the ACC. At the same time, it provides a calculation method for ESC compensation torque when the vehicle decelerates. Through the ACC torque monitoring system, a certain reasonable range of motor torque control is ensured to ensure driving safety, and at the same time, the reliability of ESC hydraulic brake compensation is improved.

The present invention provides an adaptive cruise control feedback braking torque monitoring method for an electric vehicle, the method comprising:

When the vehicle enters the adaptive cruise control state, real-time monitoring of the actual motor feedback braking torque and the current vehicle speed;

When the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the first threshold, and the integral value within the first preset time period exceeds the second threshold, it is considered that the motor feedback braking is not enough for the The whole vehicle reaches a reasonable deceleration, and the vehicle stability control system enters the pre-filling stage; when the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the third threshold, and the integral within the second preset time period value exceeds the fourth threshold, it is judged that the vehicle stability control system is required to provide hydraulic braking;

In one embodiment, when the adaptive cruise control system is not activated or the driver has stepped on the gas pedal or the motor feedback braking capability is limited and cannot provide generating torque, the difference between the target motor feedback braking torque and the actual braking torque is no longer monitored. The motor feeds back the braking torque.

In one embodiment, the first preset time period or the second preset time period is adjustable.

In one embodiment, the method also includes:

According to the current vehicle speed of the vehicle monitored in real time, the current deceleration of the vehicle is calculated, and the target deceleration calculated through the relative distance and relative speed of the vehicle in front of the target and the current deceleration of the vehicle are compared The difference is integrated within an integral time period. If the integral value is greater than the fifth threshold, it is judged that the motor feedback braking capability cannot meet the braking performance of the vehicle. At this time, the vehicle stability control system needs to provide hydraulic braking to meet vehicle braking performance.

In one embodiment, when the adaptive cruise control system is not activated, or the driver steps on the gas pedal or the acceleration of the vehicle is greater than 0 or the motor feedback braking capability is limited, the integral value is reset to 0, It means that the whole vehicle does not need to brake at this time or the braking is completely completed by the vehicle stability control system.

In one embodiment, the integration period is adjustable.

In one embodiment, the integration time period is 500 milliseconds before the current moment or 1000 milliseconds before the current moment.

In one embodiment, the method also includes:

According to the current vehicle speed of the vehicle monitored in real time, the current deceleration of the vehicle is calculated, and the target deceleration calculated through the relative distance and relative speed of the vehicle in front of the target and the current deceleration of the vehicle are compared The difference is integrated within an integral time period. If the integral value is greater than the sixth threshold, it is considered that the motor feedback braking is insufficient and has seriously affected the braking safety; When the integral value is greater than the seventh threshold value, it is judged that the motor drive torque is not enough to drive the vehicle to drive normally, and at this time, the adaptive cruise control system is controlled to be turned off; when it is detected that the target deceleration is higher than the motor feedback braking capacity , and the target acceleration is lower than the motor drive capability, the integral value can be reset to 0.

In one embodiment, the integration time period is 500 milliseconds before the current moment or 1000 milliseconds before the current moment.

In one embodiment, the method further includes: when the vehicle stability control system is required to provide hydraulic braking, calculating the required hydraulic braking deceleration of the vehicle stability control system, the calculation method is:

The requested hydraulic brake pressure compensation torque of the vehicle stability control system is calculated according to the target motor feedback braking torque minus the actual motor feedback braking torque, and the hydraulic pressure compensation torque is obtained by multiplying the requested hydraulic braking pressure compensation torque by a conversion factor Pressure compensation deceleration, obtaining the final requested hydraulic braking deceleration of the vehicle stability control system according to the hydraulic pressure compensation deceleration and the allocated hydraulic braking deceleration of the vehicle stability control system.

The ACC feedback braking torque monitoring method provided by the present invention can ensure driving safety and improve the reliability of ESC hydraulic brake compensation; and the monitoring method is suitable for electric vehicles, and has the advantages of high efficiency, low cost and precise control.

Description of drawings

The above summary of the invention and the following specific implementation methods of the present invention will be better understood when read in conjunction with the accompanying drawings. It should be noted that the drawings are merely examples of the claimed invention. In the drawings, the same reference numerals represent the same or similar elements.

FIG. 1A shows a method for monitoring regenerative braking torque of an adaptive cruise control for an electric vehicle according to an embodiment of the present invention;

Fig. 1B shows a method for monitoring regenerative braking torque of an adaptive cruise control for an electric vehicle according to an embodiment of the present invention.

Detailed ways

The detailed features and advantages of the present invention are described in detail below in the specific embodiments, the content of which is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly, and according to the specification, claims and drawings disclosed in this specification , those skilled in the art can easily understand the related objects and advantages of the present invention.

The invention provides an ACC feedback braking torque monitoring method for electric vehicles, which is used for real-time monitoring of motor output negative torque during ACC feedback braking, vehicle deceleration, accelerator pedal opening, and vehicle speed changes. When the braking torque requested by ACC is inconsistent, the monitoring system requests ESC to intervene in hydraulic braking if the error integral value exceeds a certain threshold within a certain period of time; or when it detects that the deceleration requested by ACC is inconsistent with the current deceleration When the error integral value within a certain period of time exceeds a certain threshold, the monitoring system requests ESC to intervene in hydraulic braking; or when it detects that the ACC requested deceleration is inconsistent with the current vehicle deceleration, the error integral value within a certain period of time exceeds a certain threshold , and without stepping on the accelerator, when the acceleration requested by ACC is inconsistent with the current acceleration of the vehicle, and the integral value of the error within a certain period of time exceeds a certain threshold, it means that the motor feedback braking or driving in the case of ACC cannot meet the requirements of the vehicle. Driving needs, the monitoring system requests to turn off the ACC. At the same time, it provides a calculation method for ESC compensation torque when the vehicle decelerates. Through the ACC torque monitoring system, a certain reasonable range of motor torque control is ensured to ensure driving safety, and at the same time, the reliability of ESC hydraulic brake compensation is improved.

When the whole vehicle enters the ACC state and detects that there is a target ahead, and the speed of the target is lower than the speed of the vehicle, the ACC system controls the vehicle to enter the braking condition in order to avoid rear-end collision. The ACC system calculates the target deceleration of the vehicle based on the relative speed and distance between the vehicle and the target, and calculates the target braking torque of the motor based on the feedback braking capacity of the motor and the current deceleration of the vehicle. Motor braking.

As shown in Figure 1A, the monitoring system of the present invention monitors the actual torque output of the motor in real time. If the difference is greater than the first threshold, and the integral value within a certain preset time period exceeds the second threshold, it is considered that the motor feedback braking is not enough to allow the vehicle to achieve a reasonable deceleration, and the ESC enters the pre-filling stage, that is, provides hydraulic pressure. The readiness function achieves brake response times by eliminating play between brake pads and brake discs. Wherein, the preset time period is movable or the preset time period is variable. When the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the third threshold, and the integral value within a certain preset time period exceeds the fourth threshold, wherein the time period is moving or variable , requires ESC to provide hydraulic braking (ie, request ESC hydraulic access). When the ACC is not activated or the driver has stepped on the gas pedal or the motor feedback braking capability is limited, the power generation torque cannot be provided. At this time, the monitoring system no longer monitors the target torque of the motor and the current torque of the motor.

As shown in Figure 1B, the monitoring system of the present invention monitors the current vehicle speed of the vehicle in real time, and calculates the rate of change of the vehicle speed under the current working condition, that is, the current deceleration of the vehicle, the target calculated by the relative distance and relative speed between the vehicle and the target The difference between the deceleration (that is, the braking deceleration requested by ACC) and the current deceleration of the vehicle is integrated within a certain preset time period, and the integration time is movable or variable. In one embodiment, the integration time may be 500 milliseconds before the current moment. In yet another embodiment, the integration time may be 1000 milliseconds. If the integral value is greater than the fifth threshold value, it is considered that the motor regenerative braking cannot meet the braking performance of the whole vehicle. At this time, the ESC needs to provide hydraulic braking (that is, request the ESC hydraulic pressure access) to meet the braking performance of the whole vehicle. When the ACC is not activated, or the driver has stepped on the accelerator, or the acceleration of the vehicle is greater than 0, or the braking capability of the motor feedback is limited, the integral value is reset to 0, indicating that the vehicle does not need to brake or the brake is fully delivered. Give ESC to finish.

The monitoring system monitors the current speed of the vehicle in real time, and calculates the rate of change of the vehicle speed under the current working conditions, that is, the current deceleration of the vehicle. The speed difference is integrated within a certain preset time period, and the integration time is mobile or variable. In one embodiment, the integration time may be 500 milliseconds before the current moment. In yet another embodiment, the integration time may be 1000 milliseconds. If the integral value is greater than the sixth threshold value, it is considered that insufficient motor feedback braking has seriously affected the braking safety; when the driver has not stepped on the accelerator, the integral value is greater than the seventh threshold value in driving conditions, and the motor The driving torque is not enough to drive the vehicle normally, at this time the monitoring system controls the adaptive cruise system to be turned off (ie, requests ACC to be turned off). When it is detected that the target deceleration (absolute value) is higher than the motor feedback braking capability, and the target acceleration is lower than the motor driving capability, the integral value can be reset to 0.

Since the hydraulic braking force signal provided by the supplier is interfaced with the driving assistance controller as a deceleration signal, it is necessary to convert the hydraulic braking pressure compensation torque into deceleration. ESC request hydraulic brake deceleration calculation is based on the required brake torque minus the current motor feedback torque to get the ESC request hydraulic brake pressure compensation torque, multiply the hydraulic pressure compensation torque by the conversion factor to get the hydraulic pressure compensation deceleration, according to this compensation deduction Velocity and the assigned ESC hydraulic brake deceleration yield the final ESC requested hydraulic brake deceleration. Specifically, the target deceleration calculation of the vehicle is based on the brake pedal opening to obtain the required braking torque and then multiplied by the torque conversion to obtain the target deceleration a _tar , the target deceleration a _tar is subtracted from the vehicle driving resistance deceleration to obtain the required braking torque from the ESC The deceleration a _brk achieved by the brake hydraulic brake pressure and the motor feedback torque, the motor feedback deceleration a _moter is obtained by using the motor feedback torque through the torque conversion factor, and the deceleration is low-pass filtered and the maximum and minimum values are limited To get a smooth and continuous motor feedback deceleration a _{moter_new} , subtract a _{moter_new} from a _moter to get the insufficient motor feedback torque to get the ESC extra hydraulic compensation deceleration, plus the original hydraulic pressure a _brk minus the motor feedback deceleration a _moter to get the final ESC requests hydraulic brake deceleration.

The adaptive cruise control feedback braking torque monitoring method for electric vehicles provided by the present invention can ensure driving safety and improve the reliability of ESC hydraulic brake compensation; and the monitoring method is suitable for electric vehicles and has high efficiency, low cost and The advantages of precise control.

The present invention provides an adaptive cruise control feedback braking torque monitoring method for an electric vehicle, the method comprising:

When the vehicle enters the adaptive cruise control state, real-time monitoring of the actual motor feedback braking torque and the current vehicle speed;

When the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the first threshold, and the integral value within the first preset time period exceeds the second threshold, it is considered that the motor feedback braking is not enough for the The whole vehicle reaches a reasonable deceleration, and the vehicle stability control system enters the pre-filling stage; when the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the third threshold, and the integral within the second preset time period value exceeds the fourth threshold, it is judged that the vehicle stability control system is required to provide hydraulic braking;

In one embodiment, when the adaptive cruise control system is not activated or the driver has stepped on the gas pedal or the motor feedback braking capability is limited and cannot provide generating torque, the difference between the target motor feedback braking torque and the actual braking torque is no longer monitored. The motor feeds back the braking torque.

In one embodiment, the first preset time period or the second preset time period is adjustable.

In one embodiment, the method also includes:

According to the current vehicle speed of the vehicle monitored in real time, the current deceleration of the vehicle is calculated, and the target deceleration calculated through the relative distance and relative speed of the vehicle in front of the target and the current deceleration of the vehicle are compared The difference is integrated within an integral time period. If the integral value is greater than the fifth threshold, it is judged that the motor feedback braking capability cannot meet the braking performance of the vehicle. At this time, the vehicle stability control system needs to provide hydraulic braking to meet vehicle braking performance.

In one embodiment, when the adaptive cruise control system is not activated, or the driver steps on the gas pedal or the acceleration of the vehicle is greater than 0 or the motor feedback braking capability is limited, the integral value is reset to 0, It means that the whole vehicle does not need to brake at this time or the braking is completely completed by the vehicle stability control system.

In one embodiment, the integration period is adjustable.

In one embodiment, the integration time period is 500 milliseconds before the current moment or 1000 milliseconds before the current moment.

In one embodiment, the method also includes:

According to the current vehicle speed of the vehicle monitored in real time, the current deceleration of the vehicle is calculated, and the target deceleration calculated through the relative distance and relative speed of the vehicle in front of the target and the current deceleration of the vehicle are compared The difference is integrated within an integral time period. If the integral value is greater than the sixth threshold, it is considered that the motor feedback braking is insufficient and has seriously affected the braking safety; When the integral value is greater than the seventh threshold value, it is judged that the motor drive torque is not enough to drive the vehicle to drive normally, and at this time, the adaptive cruise control system is controlled to be turned off; when it is detected that the target deceleration is higher than the motor feedback braking capacity , and the target acceleration is lower than the motor drive capability, the integral value can be reset to 0.

In one embodiment, the integration time period is 500 milliseconds before the current moment or 1000 milliseconds before the current moment.

In one embodiment, the method further includes: when the vehicle stability control system is required to provide hydraulic braking, calculating the required hydraulic braking deceleration of the vehicle stability control system, the calculation method is:

The requested hydraulic brake pressure compensation torque of the vehicle stability control system is calculated according to the target motor feedback braking torque minus the actual motor feedback braking torque, and the hydraulic pressure compensation torque is obtained by multiplying the requested hydraulic braking pressure compensation torque by a conversion factor Pressure compensation deceleration, combining the hydraulic pressure compensation deceleration and the allocated hydraulic braking deceleration of the vehicle stability control system to obtain the final requested hydraulic braking deceleration of the vehicle stability control system.

The terms and expressions used here are for description only, and the present invention should not be limited to these terms and expressions. The use of these terms and expressions does not mean to exclude any equivalent features shown and described (or parts thereof), and it should be recognized that various modifications may also be included within the scope of the claims. Other modifications, changes and substitutions are also possible. Accordingly, the claims should be read to cover all such equivalents.

Similarly, it should be pointed out that although the present invention has been described with reference to the current specific embodiments, those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, without departing from the present invention. Various equivalent changes or substitutions can also be made under the spirit of the present invention. Therefore, as long as the changes and modifications to the above embodiments are within the spirit of the present invention, they will all fall within the scope of the claims of the present application.

Claims (10)

1. an adaptive cruise control feedback braking torque monitoring method for electric vehicle, it is characterized in that, described method comprises: When the vehicle enters the adaptive cruise control state, real-time monitoring of the actual motor feedback braking torque and the current vehicle speed; When the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the first threshold, and the integral value within the first preset time period exceeds the second threshold, it is considered that the motor feedback braking is not enough for the The whole vehicle reaches a reasonable deceleration, and the vehicle stability control system enters the pre-filling stage; when the difference between the target motor feedback braking torque and the actual motor feedback braking torque is greater than the third threshold, and the integral within the second preset time period If the value exceeds the fourth threshold, it is determined that the vehicle stability control system needs to provide hydraulic braking. 2. The adaptive cruise control feedback braking torque monitoring method for electric vehicles as claimed in claim 1, wherein when the adaptive cruise control system is not in active state or the driver has stepping on the gas pedal operation or motor feedback system The dynamic capacity is limited, and the generating torque cannot be provided. At this time, the target motor feedback braking torque and the actual motor feedback braking torque are no longer monitored. 3 . The adaptive cruise control feedback braking torque monitoring method for electric vehicles according to claim 1 , wherein the first preset time period or the second preset time period is adjustable. 4 . 4. the adaptive cruise control feedback braking torque monitoring method for electric vehicle as claimed in claim 1, is characterized in that, also comprises: According to the current vehicle speed of the vehicle monitored in real time, the current deceleration of the vehicle is calculated, and the target deceleration calculated through the relative distance and relative speed of the vehicle in front of the target and the current deceleration of the vehicle are compared The difference is integrated within an integral time period. If the integral value is greater than the fifth threshold, it is judged that the motor feedback braking capability cannot meet the braking performance of the vehicle. At this time, the vehicle stability control system needs to provide hydraulic braking to meet vehicle braking performance. 5. The adaptive cruise control feedback braking torque monitoring method for electric vehicles as claimed in claim 4, characterized in that, when the adaptive cruise control system is not in an active state, or the driver has stepped on the gas pedal operation or the entire vehicle If the acceleration is greater than 0 or the motor feedback braking capability is limited, the integral value is reset to 0, indicating that the vehicle does not need to brake at this time or the braking is completely completed by the vehicle stability control system. 6 . The adaptive cruise control feedback braking torque monitoring method for electric vehicles according to claim 4 , wherein the integral time period is adjustable. 7 . 7. The adaptive cruise control feedback braking torque monitoring method for electric vehicles according to claim 4, wherein the integration time period is 500 milliseconds before the current moment or 1000 milliseconds before the current moment. 8. the adaptive cruise control feedback braking torque monitoring method for electric vehicle as claimed in claim 1, is characterized in that, also comprises: According to the current vehicle speed of the vehicle monitored in real time, the current deceleration of the vehicle is calculated, and the target deceleration calculated through the relative distance and relative speed of the vehicle in front of the target and the current deceleration of the vehicle are compared The difference is integrated within an integral time period. If the integral value is greater than the sixth threshold, it is considered that the motor feedback braking is insufficient and has seriously affected the braking safety; When the integral value is greater than the seventh threshold value, it is judged that the motor drive torque is not enough to drive the vehicle normally, and the adaptive cruise control system is turned off at this time; when it is detected that the target deceleration is higher than the motor feedback braking capacity, and When the target acceleration is lower than the motor driving capability, the integral value can be reset to 0. 9. The adaptive cruise control regenerative braking torque monitoring method for electric vehicles according to claim 8, wherein the integration time period is 500 milliseconds before the current moment or 1000 milliseconds before the current moment. 10. The adaptive cruise control feedback braking torque monitoring method for an electric vehicle as claimed in claim 1, further comprising: when the vehicle stability control system is required to provide hydraulic braking, calculating the vehicle stability control The system's requested hydraulic brake deceleration, calculated as: The requested hydraulic brake pressure compensation torque of the vehicle stability control system is calculated according to the target motor feedback braking torque minus the actual motor feedback braking torque, and the hydraulic pressure compensation torque is obtained by multiplying the requested hydraulic braking pressure compensation torque by a conversion factor Pressure compensation deceleration, obtaining the final requested hydraulic braking deceleration of the vehicle stability control system according to the hydraulic pressure compensation deceleration and the allocated hydraulic braking deceleration of the vehicle stability control system.

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