CN117068129A - Control strategy and control system for failure of braking function of electric drive system - Google Patents

Abstract

The embodiment of the application provides a control strategy and a control system for a braking function failure of an electric drive system, and belongs to the technical field of electric automobiles. The control strategy comprises the following steps: acquiring a brake master cylinder stroke effectiveness signal of a vehicle; judging whether the brake master cylinder stroke validity signal is valid or not; executing a drive torque limiting or feedback torque limiting operation under the condition that the brake master cylinder stroke validity signal is judged to be valid; executing a torque limiting operation in the event that the master cylinder travel availability signal is determined to be invalid; judging whether the vehicle has a braking failure or not; and under the condition that the vehicle is judged to have braking failure, controlling the motor to enter an ASC mode or a FW mode. The control strategy and the control system can enable the motor to enter a safe state in time when the braking function of the vehicle is invalid, and ensure the safety of vehicle driving.

Description

Control strategy and control system for failure of braking function of electric drive system

Technical Field

The application relates to the technical field of electric automobiles, in particular to a control strategy and a control system for an electric drive system when a braking function fails.

Background

With the continuous development of new energy automobiles, the safety problem of the new energy automobiles is receiving more and more attention. The most central requirements of the national for new energy automobiles are safety and stability, and the national requirements hope that the national requirements can fundamentally guarantee the life and property safety of drivers and passengers in the running process, and the new energy automobile braking system plays a very important role in the running process. The automobile braking system is mainly applied to the optimal range that the slip rate between the wheels of the automobile and the ground is kept between 5% and 20% when the automobile needs to tread the brake due to an emergency in the normal running process of the automobile, and the situation that the automobile is thrown out to the side due to the excessively high running speed can be avoided.

How to ensure the safety of the vehicle when the braking function fails is critical, but the braking function is clear, but the realization of the function cannot be ensured, so that a functional safety control system needs to be designed to ensure that the vehicle can safely stop and ensure the driving safety of the vehicle when the braking function fails.

Disclosure of Invention

The application aims to provide a control strategy and a control system for a failure of a braking function of an electric drive system, wherein the control strategy and the control system can enable a motor to enter a safe state in time when the braking function of a vehicle fails, so that the driving safety of the vehicle is ensured.

In order to achieve the above object, an embodiment of the present application provides a control strategy for a braking function failure of an electric drive system, including:

acquiring a brake master cylinder stroke effectiveness signal of a vehicle;

judging whether the brake master cylinder stroke validity signal is valid or not;

executing a drive torque limiting or feedback torque limiting operation under the condition that the brake master cylinder stroke validity signal is judged to be valid;

executing a torque limiting operation in the event that the master cylinder travel availability signal is determined to be invalid;

judging whether the vehicle has a braking failure or not;

and under the condition that the vehicle is judged to have braking failure, controlling the motor to enter an ASC mode or a FW mode.

Optionally, performing a drive torque limiting or feedback torque limiting operation includes:

acquiring a brake master cylinder stroke of the vehicle;

judging whether the stroke of the brake master cylinder is larger than a preset first distance threshold value or not;

acquiring a torque signal of a vehicle under the condition that the travel of the brake master cylinder is judged to be larger than the first distance threshold value;

determining a gear mode of a current vehicle;

judging whether the torque signal is greater than 0 under the condition that the vehicle is in a forward gear;

determining the current torque as the driving torque under the condition that the vehicle is judged to be in a forward gear and the torque signal is larger than 0;

in the case where the current torque is the driving torque, performing a driving torque limiting operation;

after a preset first duration of the operation of limiting the driving torque is executed, judging whether the absolute value of the torque signal is larger than a preset first torque threshold value or not;

and determining that the vehicle is abnormal in torque under the condition that the absolute value of the torque signal is larger than the first torque threshold value.

Optionally, performing a drive torque limiting or feedback torque limiting operation includes:

judging whether the torque signal is smaller than 0 or not under the condition that the vehicle is in a reverse gear;

and determining the current torque as the driving torque under the condition that the vehicle is judged to be in a reverse gear and the torque signal is smaller than 0.

Optionally, performing a drive torque limiting or feedback torque limiting operation includes:

and determining that the vehicle is not abnormal in torque under the condition that the absolute value of the torque signal is less than or equal to the first torque threshold value.

Optionally, performing a drive torque limiting or feedback torque limiting operation includes:

judging whether the travel of the brake master cylinder is smaller than or equal to a preset second distance threshold value or not under the condition that the travel of the brake master cylinder is smaller than or equal to the first distance threshold value;

acquiring a torque signal of the vehicle under the condition that the travel of the brake master cylinder is less than the second distance threshold value;

determining a gear mode of a current vehicle;

judging whether the vehicle is in a forward gear or not, and judging whether the torque signal is smaller than 0 or not;

determining that the current torque is feedback torque under the condition that the vehicle is judged to be a forward gear and the torque signal is smaller than 0;

executing feedback torque limiting operation under the condition that the current torque is feedback torque;

after a preset first time period for limiting feedback torque operation is executed, judging whether the torque signal is smaller than a preset second torque threshold value or not;

and determining that the vehicle is abnormal in torque under the condition that the torque signal is smaller than the second torque threshold value.

Optionally, performing a drive torque limiting or feedback torque limiting operation includes:

and under the condition that the torque signal is larger than or equal to the second torque threshold value, determining that the vehicle is not abnormal in torque.

Optionally, performing the torque limiting operation includes:

performing a torque limiting operation of the vehicle;

acquiring a torque signal of the vehicle;

after a preset first duration of limiting the torque operation of the vehicle is executed, judging whether the absolute value of the torque signal is greater than a preset third torque threshold value;

and determining that the vehicle is abnormal in torque under the condition that the absolute value of the torque signal is larger than the third torque threshold value.

Optionally, performing the torque limiting operation includes:

and determining that the vehicle is not abnormal in torque under the condition that the absolute value of the torque signal is less than or equal to the third torque threshold value.

Optionally, determining whether the vehicle has a brake failure includes:

determining a first continuous sampling time of the abnormal torque of the vehicle under the condition that the abnormal torque of the vehicle occurs;

judging whether the first continuous sampling time is greater than or equal to a preset first time threshold value;

and under the condition that the first continuous sampling time is larger than or equal to the first time threshold value, determining that the vehicle has braking failure.

In another aspect, the present application also provides a control system for an electric drive system in the event of a failure of a braking function, the control system comprising a controller for executing a control strategy as described in any one of the above.

According to the technical scheme, the control strategy and the control system for the failure of the braking function of the electric drive system judge whether the braking master cylinder stroke validity signal of the vehicle is valid or not by acquiring the braking master cylinder stroke validity signal of the vehicle, determine whether the vehicle is subjected to braking failure or not according to the execution result, and control the motor to enter a safe state, namely enter an ASC mode or an FW mode under the condition that the vehicle is subjected to braking failure, so that the motor is timely brought into the safe state when the braking function of the vehicle is failed, and the driving safety of the vehicle is ensured.

Additional features and advantages of embodiments of the application will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain, without limitation, the embodiments of the application. In the drawings:

FIG. 1 is a flow chart of a control strategy and control system upon failure of an electric drive system braking function in accordance with one embodiment of the present application;

FIG. 2 is a flow chart of a control strategy and control system implementing a limited drive torque or limited feedback torque operation upon failure of an electric drive system braking function in accordance with one embodiment of the present application;

FIG. 3 is a flow chart of a control strategy and control system implementing a torque limiting operation upon failure of an electric drive system braking function in accordance with one embodiment of the present application;

FIG. 4 is a flow chart of a control strategy and control system for determining whether a vehicle has a braking failure when the electric drive system braking function fails, according to one embodiment of the present application;

FIG. 5 is a detailed flow chart of a control strategy and control system upon failure of an electric drive system braking function in accordance with one embodiment of the present application.

Detailed Description

The following describes the detailed implementation of the embodiments of the present application with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the application, are not intended to limit the application.

FIG. 1 is a flow chart of a control strategy and control system in the event of a failure of an electric drive system braking function in accordance with one embodiment of the present application. In this fig. 1, the specific steps of the control strategy may include:

in step S10, a master cylinder stroke validity signal of the vehicle is acquired;

the brake master cylinder stroke validity signal is a signal for judging whether the vehicle is in a normal driving state or not, if abnormal conditions such as collision of the vehicle occur, the acquired brake master cylinder stroke data are invalid, the brake master cylinder stroke validity signal is invalid, and whether the acquired brake master cylinder stroke data are valid or not can be judged according to the brake master cylinder stroke validity signal;

in step S11, it is determined whether the master cylinder stroke validity signal is valid;

in step S12, in the case where it is judged that the master cylinder stroke validity signal is valid, a drive torque restriction or feedback torque restriction operation is performed;

the condition for determining whether the current torque is the driving torque or the feedback torque is: when the vehicle is in a forward gear, the torque signal is larger than 0 and is the driving torque, the vehicle working condition is a forward electric working condition, the torque signal is smaller than 0 and is the feedback torque, the vehicle working condition is a forward power generation working condition, and the motor generates power; when the vehicle is in reverse gear, the torque signal is less than 0 and is the driving torque, the vehicle working condition is the backward electric working condition, and the judgment that the torque signal is greater than 0 is not set because the vehicle does not have the working condition of backward power generation;

in step S13, in the case where it is determined that the master cylinder stroke validity signal is invalid, a torque limiting operation is performed;

in step S14, it is determined whether or not the vehicle has a brake failure;

in step S15, if it is determined that the vehicle has a brake failure, the motor is controlled to enter an ASC mode or a FW mode.

FIG. 2 is a flow chart of a control strategy and control system implementing a limited drive torque or limited feedback torque operation upon failure of an electric drive system braking function in accordance with one embodiment of the present application. In this embodiment, the specific step of performing the operation of limiting the driving torque or limiting the feedback torque may be various steps known to those skilled in the art. In a preferred example of the present application, the limiting driving torque or limiting feedback torque operation may be performed as shown in fig. 2. In this fig. 2, a method of performing a driving torque limiting or feedback torque limiting operation may include:

in step S121, a master cylinder stroke of the vehicle is acquired;

in step S122, it is determined whether the master cylinder stroke is greater than a preset first distance threshold;

in step S1201, in the case where it is determined that the master cylinder stroke is greater than the first distance threshold value, a torque signal of the vehicle is acquired;

judging that the travel of the brake master cylinder is overlarge when the travel of the brake master cylinder is larger than a first distance threshold value, and limiting the driving torque of the vehicle;

in step S1202, a gear mode of the current vehicle is determined;

in step S1203, if the vehicle is in a forward gear, it is determined whether the torque signal is greater than 0; judging whether the torque signal is smaller than 0 or not under the condition that the vehicle is in a reverse gear, wherein the step aims at judging whether the current torque is a driving torque or not;

in step S1204, when it is determined that the vehicle is in a forward gear and the torque signal is greater than 0, determining that the current torque is the driving torque; when the vehicle is judged to be in a reverse gear and the torque signal is smaller than 0, determining the current torque as the driving torque,

on the contrary, when the vehicle is determined to be in the forward gear and the torque signal is less than 0, the step of determining whether the current torque is the driving torque may be performed in return, that is, step S1203 is performed;

in step S1205, in the case where the current torque is the driving torque, a limit driving torque operation is performed;

in step S1206, after performing the drive torque limiting operation for a preset first period of time, it is determined whether the absolute value of the torque signal is greater than a preset first torque threshold;

after limiting the driving torque for a period of time, judging the limiting effect;

in step S1207, in the case where it is determined that the absolute value of the torque signal is greater than the first torque threshold, it is determined that the vehicle is abnormal in torque;

in step S1208, in the case where it is determined that the absolute value of the torque signal is less than or equal to the first torque threshold value, it is determined that the torque abnormality does not occur in the vehicle;

in step S1211, in the case where it is determined that the master cylinder stroke is less than or equal to the first distance threshold value, it is determined whether the master cylinder stroke is less than a preset second distance threshold value;

in step S1212, if it is determined that the master cylinder stroke is less than the second distance threshold, a torque signal of the vehicle is acquired;

judging that the travel of the brake master cylinder is too small when the travel of the brake master cylinder is smaller than a second distance threshold value, and limiting feedback torque at the moment;

in step S1213, a gear mode of the current vehicle is determined;

in step S1214, it is determined whether the vehicle is in a forward gear and the torque signal is less than 0, and the purpose of this step is to determine whether the current torque is a feedback torque;

in step S1215, in the case where it is determined that the vehicle is in the forward gear and the torque signal is less than 0, it is determined that the current torque is the feedback torque,

on the contrary, when the vehicle is determined to be in the forward gear, the torque signal is greater than 0 or the vehicle is in the reverse gear, and the torque signal is less than 0, the step of determining whether the current torque is the feedback torque may be performed again, that is, step S1214 may be performed;

in step S1216, in the case where the current torque is the feedback torque, a feedback torque limiting operation is performed;

in step S1217, after performing the preset first duration of the feedback torque limiting operation, it is determined whether the torque signal is less than a preset second torque threshold;

after limiting feedback torque for a period of time, judging a limiting effect;

in step S1218, in the case where it is determined that the torque signal is smaller than the second torque threshold value, it is determined that the vehicle is abnormal in torque;

in step S1219, in the case where it is determined that the torque signal is greater than or equal to the second torque threshold value, it is determined that the vehicle is not experiencing a torque abnormality.

FIG. 3 is a flow chart of a control strategy and control system implementing a torque limiting operation upon failure of an electric drive system braking function in accordance with one embodiment of the present application. In this embodiment, for the specific step of performing the torque limiting operation, various steps known to those skilled in the art may be used. In a preferred example of the present application, the torque limiting operation may be performed as shown in fig. 3. In this fig. 3, a method of performing a torque limiting operation may include:

in step S131, a torque limiting operation of the vehicle is performed;

in step S132, a torque signal of the vehicle is acquired;

in step S133, after a preset first period of time to limit the torque operation of the vehicle is performed, it is determined whether the absolute value of the torque signal is greater than a preset third torque threshold;

after limiting torque is executed for a period of time, judging a limiting effect;

in step S134, in the case where it is determined that the absolute value of the torque signal is greater than the third torque threshold, it is determined that the vehicle is abnormal in torque;

in step S135, in the case where it is determined that the absolute value of the torque signal is less than or equal to the third torque threshold value, it is determined that the torque abnormality does not occur in the vehicle.

Fig. 4 is a flow chart of a control strategy and control system for determining whether a vehicle has a braking failure when the electric drive system braking function fails, according to one embodiment of the present application. In this embodiment, the specific step of determining whether the vehicle has a brake failure may be various steps known to those skilled in the art. In a preferred example of the present application, determining whether the vehicle has a brake failure may be the step shown in fig. 4. In this fig. 4, a method of determining whether a vehicle has a brake failure may include:

in step S141, in the case where the vehicle has a torque abnormality, determining a first continuous sampling time when the vehicle has a torque abnormality, and determining a duration abnormality time is required;

in step S142, it is determined whether the first continuous sampling time is greater than or equal to a preset first time threshold;

in step S143, if it is determined that the first continuous sampling time is greater than or equal to the first time threshold, it is determined that a braking failure occurs in the vehicle;

in step S144, in the case where it is determined that the first continuous sampling time is less than the first time threshold, it is determined that the vehicle has not failed in braking.

Fig. 5 is a detailed flowchart of a control strategy and a control system when the braking function of the electric drive system fails according to one embodiment of the present application, and detailed steps of the control strategy when the braking function of the electric drive system fails are shown in fig. 5.

In another aspect, the present application also provides a control system for an electric drive system in the event of a failure of a braking function, the control system comprising a controller for executing a control strategy as described in any one of the above. The control strategy is specifically shown in fig. 1 to 5.

FIG. 1 is a flow chart of a control strategy and control system in the event of a failure of an electric drive system braking function in accordance with one embodiment of the present application. In this fig. 1, the specific steps of the control strategy may include:

in step S10, a master cylinder stroke validity signal of the vehicle is acquired;

the brake master cylinder stroke validity signal is a signal for judging whether the vehicle is in a normal driving state or not, if abnormal conditions such as collision of the vehicle occur, the acquired brake master cylinder stroke data are invalid, the brake master cylinder stroke validity signal is invalid, and whether the acquired brake master cylinder stroke data are valid or not can be judged according to the brake master cylinder stroke validity signal;

in step S11, it is determined whether the master cylinder stroke validity signal is valid;

in step S12, in the case where it is judged that the master cylinder stroke validity signal is valid, a drive torque restriction or feedback torque restriction operation is performed;

the condition for determining whether the current torque is the driving torque or the feedback torque is: when the vehicle is in a forward gear, the torque signal is larger than 0 and is the driving torque, the vehicle working condition is a forward electric working condition, the torque signal is smaller than 0 and is the feedback torque, the vehicle working condition is a forward power generation working condition, and the motor generates power; when the vehicle is in reverse gear, the torque signal is less than 0 and is the driving torque, the vehicle working condition is the backward electric working condition, and the judgment that the torque signal is greater than 0 is not set because the vehicle does not have the working condition of backward power generation;

in step S13, in the case where it is determined that the master cylinder stroke validity signal is invalid, a torque limiting operation is performed;

in step S14, it is determined whether or not the vehicle has a brake failure;

in step S15, if it is determined that the vehicle has a brake failure, the motor is controlled to enter an ASC mode or a FW mode.

FIG. 2 is a flow chart of a control strategy and control system implementing a limited drive torque or limited feedback torque operation upon failure of an electric drive system braking function in accordance with one embodiment of the present application. In this embodiment, the specific step of performing the operation of limiting the driving torque or limiting the feedback torque may be various steps known to those skilled in the art. In a preferred example of the present application, the limiting driving torque or limiting feedback torque operation may be performed as shown in fig. 2. In this fig. 2, a method of performing a driving torque limiting or feedback torque limiting operation may include:

in step S121, a master cylinder stroke of the vehicle is acquired;

in step S122, it is determined whether the master cylinder stroke is greater than a preset first distance threshold;

in step S1201, in the case where it is determined that the master cylinder stroke is greater than the first distance threshold value, a torque signal of the vehicle is acquired;

judging that the travel of the brake master cylinder is overlarge when the travel of the brake master cylinder is larger than a first distance threshold value, and limiting the driving torque of the vehicle;

in step S1202, a gear mode of the current vehicle is determined;

in step S1203, if the vehicle is in a forward gear, it is determined whether the torque signal is greater than 0; judging whether the torque signal is smaller than 0 or not under the condition that the vehicle is in a reverse gear, wherein the step aims at judging whether the current torque is a driving torque or not;

in step S1204, when it is determined that the vehicle is in a forward gear and the torque signal is greater than 0, determining that the current torque is the driving torque; when the vehicle is judged to be in a reverse gear and the torque signal is smaller than 0, determining the current torque as the driving torque,

on the contrary, when the vehicle is determined to be in the forward gear and the torque signal is less than 0, the step of determining whether the current torque is the driving torque may be performed in return, that is, step S1203 is performed;

in step S1205, in the case where the current torque is the driving torque, a limit driving torque operation is performed;

in step S1206, after performing the drive torque limiting operation for a preset first period of time, it is determined whether the absolute value of the torque signal is greater than a preset first torque threshold;

after limiting the driving torque for a period of time, judging the limiting effect;

in step S1207, in the case where it is determined that the absolute value of the torque signal is greater than the first torque threshold, it is determined that the vehicle is abnormal in torque;

in step S1208, in the case where it is determined that the absolute value of the torque signal is less than or equal to the first torque threshold value, it is determined that the torque abnormality does not occur in the vehicle;

in step S1211, in the case where it is determined that the master cylinder stroke is less than or equal to the first distance threshold value, it is determined whether the master cylinder stroke is less than a preset second distance threshold value;

in step S1212, if it is determined that the master cylinder stroke is less than the second distance threshold, a torque signal of the vehicle is acquired;

judging that the travel of the brake master cylinder is too small when the travel of the brake master cylinder is smaller than a second distance threshold value, and limiting feedback torque at the moment;

in step S1213, a gear mode of the current vehicle is determined;

in step S1214, it is determined whether the vehicle is in a forward gear and the torque signal is less than 0, and the purpose of this step is to determine whether the current torque is a feedback torque;

in step S1215, in the case where it is determined that the vehicle is in the forward gear and the torque signal is less than 0, it is determined that the current torque is the feedback torque,

on the contrary, when the vehicle is determined to be in the forward gear, the torque signal is greater than 0 or the vehicle is in the reverse gear, and the torque signal is less than 0, the step of determining whether the current torque is the feedback torque may be performed again, that is, step S1214 may be performed;

in step S1216, in the case where the current torque is the feedback torque, a feedback torque limiting operation is performed;

in step S1217, after performing the preset first duration of the feedback torque limiting operation, it is determined whether the torque signal is less than a preset second torque threshold;

after limiting feedback torque for a period of time, judging a limiting effect;

in step S1218, in the case where it is determined that the torque signal is smaller than the second torque threshold value, it is determined that the vehicle is abnormal in torque;

in step S1219, in the case where it is determined that the torque signal is greater than or equal to the second torque threshold value, it is determined that the vehicle is not experiencing a torque abnormality.

FIG. 3 is a flow chart of a control strategy and control system implementing a torque limiting operation upon failure of an electric drive system braking function in accordance with one embodiment of the present application. In this embodiment, for the specific step of performing the torque limiting operation, various steps known to those skilled in the art may be used. In a preferred example of the present application, the torque limiting operation may be performed as shown in fig. 3. In this fig. 3, a method of performing a torque limiting operation may include:

in step S131, a torque limiting operation of the vehicle is performed;

in step S132, a torque signal of the vehicle is acquired;

in step S133, after a preset first period of time to limit the torque operation of the vehicle is performed, it is determined whether the absolute value of the torque signal is greater than a preset third torque threshold;

after limiting torque is executed for a period of time, judging a limiting effect;

in step S134, in the case where it is determined that the absolute value of the torque signal is greater than the third torque threshold, it is determined that the vehicle is abnormal in torque;

in step S135, in the case where it is determined that the absolute value of the torque signal is less than or equal to the third torque threshold value, it is determined that the torque abnormality does not occur in the vehicle.

Fig. 4 is a flow chart of a control strategy and control system for determining whether a vehicle has a braking failure when the electric drive system braking function fails, according to one embodiment of the present application. In this embodiment, the specific step of determining whether the vehicle has a brake failure may be various steps known to those skilled in the art. In a preferred example of the present application, determining whether the vehicle has a brake failure may be the step shown in fig. 4. In this fig. 4, a method of determining whether a vehicle has a brake failure may include:

in step S141, in the case where the vehicle has a torque abnormality, determining a first continuous sampling time when the vehicle has a torque abnormality, and determining a duration abnormality time is required;

in step S142, it is determined whether the first continuous sampling time is greater than or equal to a preset first time threshold;

in step S143, if it is determined that the first continuous sampling time is greater than or equal to the first time threshold, it is determined that a braking failure occurs in the vehicle;

in step S144, in the case where it is determined that the first continuous sampling time is less than the first time threshold, it is determined that the vehicle has not failed in braking.

Fig. 5 is a detailed flowchart of a control strategy and a control system when the braking function of the electric drive system fails according to one embodiment of the present application, and detailed steps of the control strategy when the braking function of the electric drive system fails are shown in fig. 5.

According to the technical scheme, the control strategy and the control system for the failure of the braking function of the electric drive system judge whether the braking master cylinder stroke validity signal of the vehicle is valid or not by acquiring the braking master cylinder stroke validity signal of the vehicle, determine whether the vehicle is subjected to braking failure or not according to the execution result, and control the motor to enter a safe state, namely enter an ASC mode or an FW mode under the condition that the vehicle is subjected to braking failure, so that the motor is timely brought into the safe state when the braking function of the vehicle is failed, and the driving safety of the vehicle is ensured.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.

The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and variations of the present application will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the application are to be included in the scope of the claims of the present application.

Claims (10)

1. A control strategy for the failure of an electric drive system braking function, said control strategy comprising:

acquiring a brake master cylinder stroke effectiveness signal of a vehicle;

judging whether the brake master cylinder stroke validity signal is valid or not;

executing a drive torque limiting or feedback torque limiting operation under the condition that the brake master cylinder stroke validity signal is judged to be valid;

executing a torque limiting operation in the event that the master cylinder travel availability signal is determined to be invalid;

judging whether the vehicle has a braking failure or not;

and under the condition that the vehicle is judged to have braking failure, controlling the motor to enter an ASC mode or a FW mode.

2. The control strategy of claim 1, wherein performing a limited drive torque or limited feedback torque operation comprises:

acquiring a brake master cylinder stroke of the vehicle;

judging whether the stroke of the brake master cylinder is larger than a preset first distance threshold value or not;

acquiring a torque signal of a vehicle under the condition that the travel of the brake master cylinder is judged to be larger than the first distance threshold value;

determining a gear mode of a current vehicle;

judging whether the torque signal is greater than 0 under the condition that the vehicle is in a forward gear;

determining the current torque as the driving torque under the condition that the vehicle is judged to be in a forward gear and the torque signal is larger than 0;

in the case where the current torque is the driving torque, performing a driving torque limiting operation;

after a preset first duration of the operation of limiting the driving torque is executed, judging whether the absolute value of the torque signal is larger than a preset first torque threshold value or not;

and determining that the vehicle is abnormal in torque under the condition that the absolute value of the torque signal is larger than the first torque threshold value.

3. The control strategy of claim 2, wherein performing a limited drive torque or limited feedback torque operation comprises:

judging whether the torque signal is smaller than 0 or not under the condition that the vehicle is in a reverse gear;

and determining the current torque as the driving torque under the condition that the vehicle is judged to be in a reverse gear and the torque signal is smaller than 0.

4. The control strategy of claim 2, wherein performing a limited drive torque or limited feedback torque operation comprises:

and determining that the vehicle is not abnormal in torque under the condition that the absolute value of the torque signal is less than or equal to the first torque threshold value.

5. The control strategy of claim 2, wherein performing a limited drive torque or limited feedback torque operation comprises:

judging whether the travel of the brake master cylinder is smaller than or equal to a preset second distance threshold value or not under the condition that the travel of the brake master cylinder is smaller than or equal to the first distance threshold value;

acquiring a torque signal of the vehicle under the condition that the travel of the brake master cylinder is less than the second distance threshold value;

determining a gear mode of a current vehicle;

judging whether the vehicle is in a forward gear or not, and judging whether the torque signal is smaller than 0 or not;

determining that the current torque is feedback torque under the condition that the vehicle is judged to be a forward gear and the torque signal is smaller than 0;

executing feedback torque limiting operation under the condition that the current torque is feedback torque;

after a preset first time period for limiting feedback torque operation is executed, judging whether the torque signal is smaller than a preset second torque threshold value or not;

and determining that the vehicle is abnormal in torque under the condition that the torque signal is smaller than the second torque threshold value.

6. The control strategy of claim 5, wherein performing a limited drive torque or limited feedback torque operation comprises:

and under the condition that the torque signal is larger than or equal to the second torque threshold value, determining that the vehicle is not abnormal in torque.

7. The control strategy of claim 1, wherein performing a torque limiting operation comprises:

performing a torque limiting operation of the vehicle;

acquiring a torque signal of the vehicle;

after a preset first duration of limiting the torque operation of the vehicle is executed, judging whether the absolute value of the torque signal is greater than a preset third torque threshold value;

and determining that the vehicle is abnormal in torque under the condition that the absolute value of the torque signal is larger than the third torque threshold value.

8. The control strategy of claim 7, wherein performing a torque limiting operation comprises:

and determining that the vehicle is not abnormal in torque under the condition that the absolute value of the torque signal is less than or equal to the third torque threshold value.

9. The control strategy of claim 1, wherein determining whether the vehicle has a braking failure comprises:

determining a first continuous sampling time of the abnormal torque of the vehicle under the condition that the abnormal torque of the vehicle occurs;

judging whether the first continuous sampling time is greater than or equal to a preset first time threshold value;

and under the condition that the first continuous sampling time is larger than or equal to the first time threshold value, determining that the vehicle has braking failure.

10. A control system in the event of a failure of a braking function of an electric drive system, characterized in that the control system comprises a controller for executing a control strategy according to any of claims 1 to 9.