CN113442905B

CN113442905B - Chassis unbalance fault monitoring method, steering control system and automobile

Info

Publication number: CN113442905B
Application number: CN202010224226.5A
Authority: CN
Inventors: 邓念; 谷成; 刘飞; 刘咏萱; 张成宝; 周中坚; 郑冬霞; 韩东冬
Original assignee: SAIC Motor Corp Ltd
Current assignee: SAIC Motor Corp Ltd
Priority date: 2020-03-26
Filing date: 2020-03-26
Publication date: 2023-04-07
Anticipated expiration: 2040-03-26
Also published as: CN113442905A

Abstract

The invention discloses a chassis unbalance fault monitoring method based on an electric power steering system, the electric power steering control system and an automobile. Therefore, after the target power-assisted torque is applied to the electric power-assisted steering system, the steering wheel torque applied to the electric power-assisted steering system by a user can be reduced, the hand torque of the driver acting on the steering wheel is small, the extreme fatigue of the driver is avoided, the problem that the hand of the user is separated from the steering wheel due to the overlarge holding force of the steering wheel is also avoided, and safety accidents are avoided.

Description

Chassis imbalance fault monitoring method, steering control system and automobile

Technical Field

The invention relates to the field of automobiles, in particular to a chassis imbalance fault monitoring method and system based on an electric power steering system and an automobile.

Background

With the development of science and technology, automobiles are applied by more and more people as tools for riding instead of walk, and the automobiles bring portability and potential safety hazards. When a vehicle runs straight at a medium-high speed, if the problems of unbalanced chassis such as unbalanced left and right chassis main pins, unbalanced left and right tire toe and the like occur, the interference of force can be introduced to a rack of a power-assisted steering system of the vehicle, the hand moment of a driver, which maintains the high-speed straight running in the vehicle, acting on a steering wheel can be correspondingly increased, when the vehicle keeps a running state of the medium-high speed straight running for a long time, the hand moment of the driver acting on the steering wheel needs to be kept for a long time, so that the driver is extremely tired, the hand is easily separated from the steering wheel due to overlarge holding force of the steering wheel, the vehicle is quickly deviated, and safety accidents are caused.

Disclosure of Invention

The invention aims to solve the problem that when a vehicle in the prior art keeps running straight at a medium-high speed, the hand moment of a driver acting on a steering wheel for a long time is overlarge to cause a safety accident. Therefore, the invention provides a chassis imbalance fault monitoring method based on an electric power steering system.

In order to solve the above problems, an embodiment of the present invention discloses a chassis imbalance fault monitoring method based on an electric power steering system, including:

obtaining target data of a target vehicle, the target data describing steering wheel related data of the target vehicle and vehicle speed related data of the target vehicle;

judging whether the target vehicle has a chassis imbalance fault or not based on the target data;

and if the target vehicle has the chassis unbalance fault, calculating a target auxiliary torque according to a predefined rule to control a motor to output the target auxiliary torque and apply the target auxiliary torque to the electric power steering system so as to balance the steering wheel torque.

Further, in some embodiments of the invention, the target data comprises: an absolute value of a steering wheel absolute position signal of the target vehicle, an absolute value of a steering wheel torque signal of the target vehicle, and a vehicle speed signal of the target vehicle.

Further, in some embodiments of the present invention, the determining whether the target vehicle has a chassis imbalance fault based on the target data comprises:

when the target data of the target vehicle simultaneously meet the following conditions, the target vehicle has chassis unbalance fault;

the first condition is that: an absolute value of the absolute position signal of the steering wheel is less than an absolute position threshold;

the second condition is that: the absolute value of the steering wheel torque signal is less than a first torque threshold;

a third condition: the vehicle speed signal is between a first vehicle speed threshold and a second vehicle speed threshold;

a fourth condition: and controlling a counter to accumulate when the first condition, the second condition and the third condition are simultaneously met in a preset period, wherein the accumulated value of the counter reaches a target value.

Further, in some embodiments of the present invention, the monitoring method further comprises:

if the chassis imbalance fault occurs in the target vehicle, triggering and outputting a fault zone bit and storing the fault zone bit, the target data and the target auxiliary torque;

and if the target vehicle does not have the chassis imbalance fault, maintaining the current state of the vehicle.

and carrying out fault diagnosis on the chassis unbalance fault again.

Further, in some embodiments of the present invention, the performing fault diagnosis again on the chassis imbalance fault comprises:

judging whether the target assist torque continuously exceeds a threshold value within preset time;

if yes, judging that the chassis unbalance fault is a primary fault;

if not, judging that the chassis imbalance fault is a secondary fault.

Further, in some embodiments of the invention, if the absolute value of the steering wheel torque signal is greater than a second torque threshold, calculating the target assist torque comprises:

calculating a first product of a sum of the steering wheel torque signal and an initial assist torque value of the electric power steering system and a first gain;

calculating a sum of a first product of a target assist torque and a first gain of the first period and a second product of the target assist torque and a second gain of the first period;

and if the sum value is between the upper limit value and the lower limit value, taking the sum value as the target assistance torque.

Further, in some embodiments of the invention, if the absolute value of the steering wheel torque signal does not exceed a second torque threshold, calculating the target assist torque comprises:

and setting the target moment of assistance to be the same as the target moment of assistance in the previous period.

Further, in some embodiments of the present invention, an electric power steering control system is disclosed, comprising:

an acquisition module to acquire target data of a target vehicle, the target data describing steering wheel related data of the target vehicle and vehicle speed related data of the target vehicle;

the judging module is used for judging whether the target vehicle has a chassis imbalance fault or not based on the target data, and if the target vehicle has the chassis imbalance fault, entering the control module;

the control module is used for calculating a target assisting moment according to a predefined rule so as to control the motor to output the target assisting moment and apply the target assisting moment to the electric power steering system so as to balance the steering wheel moment.

Further, in some embodiments of the present invention, an automobile is disclosed that includes the above-mentioned electric power steering control system.

The embodiment of the invention discloses a chassis imbalance fault monitoring method based on an electric power steering system, which has the following beneficial effects:

and when the chassis is in unbalanced fault, calculating a target assistance torque according to a predefined rule to control the motor to output the target assistance torque and apply the target assistance torque to the electric power steering system so as to balance the steering wheel torque. Therefore, after the target power-assisted torque is applied to the electric power-assisted steering system, the steering wheel torque applied to the electric power-assisted steering system by a user can be reduced, the hand torque of the driver acting on the steering wheel is small, the extreme fatigue of the driver is avoided, the problem that the hand of the user is separated from the steering wheel due to the overlarge holding force of the steering wheel is also avoided, and safety accidents are avoided.

Additional features and corresponding advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic structural diagram of an electric power steering system according to an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a chassis imbalance fault monitoring method based on an electric power steering system according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart illustrating another method for monitoring chassis imbalance faults based on an electric power steering system according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of an electric power steering control system according to an embodiment of the present invention.

Description of reference numerals:

10: EPS;100: a torque sensor; 101: a vehicle speed sensor; 102: an electric motor; 103: a speed reduction mechanism; 104: an electronic control unit; 105: an electronic control unit.

40: an acquisition module; 50: a judgment module; 60: and a control module.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure. While the invention will be described in conjunction with the preferred embodiments, it is not intended that features of the invention be limited to these embodiments. On the contrary, the invention is described in connection with the embodiments for the purpose of covering alternatives or modifications that may be extended based on the claims of the present invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be practiced without these particulars. Moreover, some of the specific details have been left out of the description in order to avoid obscuring or obscuring the focus of the present invention. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

It should be noted that in this specification, like reference numerals and letters refer to like items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

When a vehicle runs straight at a medium and high speed, if the problems of unbalanced chassis such as unbalanced left and right chassis main pins, unbalanced left and right tire toe-in and the like occur, a force interference is introduced on a rack of an Electric Power Steering (EPS) system of the vehicle, the hand moment of a driver, which maintains the high-speed straight running in the vehicle, acting on a Steering wheel is correspondingly increased, when the vehicle keeps a running state of the medium and high-speed straight running for a long time, the hand moment of the driver acting on the Steering wheel needs to be kept for a long time, so that the driver is extremely tired, the hand is easily separated from the Steering wheel due to overlarge holding force of the Steering wheel, the vehicle is quickly deviated, and safety accidents are caused.

In order to solve the technical problems, the control of the chassis imbalance fault is arranged in the EPS, so that the situation that the holding force of a driver on a steering wheel is too large under the condition of high-speed straight-line running in a vehicle when the chassis is in an imbalance fault sign (such as unbalanced suspension, unbalanced tires and the like) is avoided, and the situation that the hand is separated from the steering wheel to cause the vehicle to be rapidly deviated is avoided or relieved, so that the driving comfort and the running safety of the vehicle under the imbalance condition of the chassis of the vehicle are improved.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an electric power steering system disclosed in an embodiment of the present invention, an EPS is a power steering system directly relying on a motor to provide an assist torque, and the structure of the EPS is not an improvement of the present invention, which can also refer to the prior art, and the embodiment of the present invention is not described herein again. The EPS 10 is mainly composed of a torque sensor 100, a vehicle speed sensor 101, a motor 102, a speed reduction mechanism 103, an Electronic Control Unit (ECU) 104, a steering wheel angle sensor 105, and the like.

The torque sensor 100 is connected with a steering shaft (pinion shaft) of a speed reducing mechanism 103, the vehicle speed sensor 101, the motor 102, the torque sensor 100 and the steering wheel angle sensor 105 are respectively connected with the ECU 104, when the steering shaft rotates, the torque sensor 100 starts to work, relative rotation angle displacement generated by an input shaft and an output shaft under the action of a torsion bar is changed into electric signals to be transmitted to the ECU 104, the ECU 104 determines the rotation direction of the motor 102 and the magnitude of power-assisted current according to the signals of the vehicle speed sensor 101 and the torque sensor 100, and accordingly real-time control of power-assisted steering is achieved. Therefore, different power assisting effects of the motor 102 can be easily realized when the vehicle speed is different, the vehicle is light and flexible when running in low-speed steering, and the vehicle is stable and reliable when running in high-speed steering.

The following describes a chassis imbalance fault monitoring method based on an electric power steering system, which is disclosed in an embodiment of the present invention, with reference to fig. 2, the chassis imbalance fault monitoring method based on the electric power steering system is mainly divided into three steps, where the first step is to perform fault prediction on a chassis imbalance fault, which may be referred to as fault symptom prediction for short, then when the chassis is in an imbalance fault state, fault mitigation control is implemented, which may be referred to as fault mitigation control for short, and the third step is to perform final fault diagnosis and determination on a chassis imbalance fault symptom, which may be referred to as fault diagnosis and determination for short. Referring to fig. 2, fig. 2 is a schematic flow chart of a method for monitoring a chassis imbalance fault based on an electric power steering system according to an embodiment of the present invention, where the method for monitoring a chassis imbalance fault based on an electric power steering system includes:

step S10: the steering wheel angle sensor acquires an absolute position signal and a torque signal of a steering wheel of a target vehicle, the ECU obtains absolute values of the absolute position signal and the torque signal by taking absolute values of the absolute position signal and the torque signal, the vehicle speed sensor acquires a vehicle speed signal of the target vehicle, and the absolute value of the absolute position signal and the vehicle speed signal are used as target data of the target vehicle. The absolute position signal refers to a deviation angle between the steering wheel angle and the middle position (0 position) of the steering wheel when the vehicle is moving straight ahead, and may be a positive value or a negative value depending on the left-right direction of the steering wheel.

Step S11: the ECU determines whether a chassis imbalance fault occurs in the target vehicle based on the target data. In some embodiments of the present invention, when the target data of the target vehicle simultaneously satisfies the following conditions, the target vehicle has a chassis imbalance fault:

the first condition is that: the absolute value of the absolute position signal of the steering wheel is less than the absolute value position threshold.

The second condition is that: the absolute value of the steering wheel torque signal is less than a first torque threshold.

A third condition: the vehicle speed signal is between a first threshold vehicle speed and a second threshold vehicle speed.

A fourth condition: and controlling a counter to accumulate when a first condition, the second condition and the third condition are simultaneously met in a preset period, wherein the accumulated value of the counter reaches a target value.

The absolute value position threshold, the first torque threshold, the vehicle speed first threshold and the vehicle speed second threshold can be determined according to actual vehicle calibration, the target value is related to the confirmation time, and the target value of the counter is determined according to the confirmation time.

In some embodiments of the present invention, when the above four conditions are simultaneously satisfied, it is determined that the target vehicle has a chassis imbalance fault, and when one of the above four conditions is not satisfied, it is determined that the target vehicle has no chassis imbalance fault. When the chassis imbalance fault occurs in the target vehicle, the state value of the output failure symptom flag of the failure symptom determination module may be set to 1, and if the state value of the output failure symptom flag of the failure symptom determination module is set to 0, the output failure symptom flag of the failure symptom determination module may be used as a start condition for performing step S12.

Step S12: when the target vehicle has a chassis imbalance fault, the target assistance torque is calculated according to a predefined rule to control the motor to output the target assistance torque and is applied to the electric power steering system to balance the steering wheel torque. When the target assist torque is calculated, the target assist torque may be calculated in a segmented manner based on a second torque threshold (obtained based on real vehicle calibration), and for example, when an absolute value of the steering wheel torque signal is greater than the second torque threshold, the target assist torque may be calculated by the following method:

taking A as the steering wheel torque, taking B as the power-assisted torque value when the target power-assisted torque is applied before the fault mitigation control, adding the A value and the B value to obtain a C value, namely C = A + B, multiplying the obtained C value by a first gain to obtain a first product D, then multiplying the target power-assisted torque of the previous period by a second gain to obtain a second product E, adding the D value and the E value to obtain a sum value F, and finally, taking G = Limit (F, a lower Limit value and an upper Limit value), wherein if the F value is between the upper Limit value and the lower Limit value, the F value is taken as the target power-assisted torque G, and if the F value is not between the upper Limit value and the lower Limit value, the target power-assisted torque is limited to take any value between the upper Limit value and the lower Limit value as the target power-assisted torque. The target moment assist in the previous period is the target moment assist in the current period, and the unit delay is taken, and the delay is one period, namely the target moment assist in the previous period. The assistance torque value when the target assistance torque is applied before the fault mitigation control can be obtained by performing assistance instruction superposition through the synthesis of some typical EPS control algorithms which guarantee the basic steering function, such as basic assistance control, active return control, yaw damping control and the like.

When the target vehicle has a chassis imbalance fault, if the absolute value of the steering wheel torque signal is not greater than the second torque threshold, the target assistance torque is calculated by the following method:

and taking the target moment G as the target moment of assistance in the previous cycle. The target moment of assistance G is set as the target moment of assistance in the previous cycle, wherein the target moment of assistance in the previous cycle is delayed by one unit for the target moment of assistance in the current cycle, and the delayed cycle is the target moment of assistance in the previous cycle.

And when the chassis imbalance fault does not occur in the target vehicle, the target assistance torque G is taken as zero.

That is, if the chassis imbalance fault occurs in the target vehicle and the absolute value of the steering wheel torque signal is greater than the second torque threshold, which indicates that the holding force on the steering wheel is too large when the high-speed straight running in the vehicle is maintained, at this time, the target assist torque needs to be calculated, the motor assist command is gradually increased, so that the steering wheel torque signal is gradually decreased, so that the holding force on the steering wheel when the high-speed straight running in the vehicle is reduced, in this process, if the absolute value of the steering wheel torque signal is continuously greater than the second torque threshold, which indicates that the holding force on the steering wheel is still too large when the high-speed straight running in the vehicle is maintained, at this time, the motor assist command needs to be continuously increased, so that the steering wheel torque signal is continuously and gradually decreased. If the absolute value of the steering wheel torque signal is no longer greater than the second torque threshold value, the steering wheel torque signal value reaches the expected torque value, and at the moment, the target assistance torque is output, so that the motor assistance command is not increased any more, and the steering wheel torque signal tends to a stable state and does not decrease gradually. And if the target vehicle does not have chassis imbalance faults, the target assistance torque is taken as zero.

The embodiment of the invention discloses a chassis imbalance fault monitoring method based on an electric power steering system. Therefore, after the target power-assisted torque is applied to the electric power-assisted steering system, the steering wheel torque applied to the electric power-assisted steering system by a user can be reduced, the hand torque of the driver acting on the steering wheel is small, the extreme fatigue of the driver is avoided, the problem that the hand of the user is separated from the steering wheel due to the overlarge holding force of the steering wheel is also avoided, and safety accidents are avoided.

Fig. 3 is a schematic flow chart of another chassis imbalance fault monitoring method based on an electric power steering system disclosed in the embodiment of the present invention, and it should be noted that the same parts of the another chassis imbalance fault monitoring method based on an electric power steering system shown in fig. 3 and the chassis imbalance fault monitoring method based on an electric power steering system shown in fig. 2 may refer to the above description, and repeated parts of the embodiment of the present invention are not repeated, and the chassis imbalance fault monitoring method based on an electric power steering system includes:

step S10: the method comprises the steps that a steering wheel angle sensor acquires an absolute position signal and a torque signal of a steering wheel of a target vehicle, an ECU obtains absolute values of the absolute position signal and the torque signal by taking absolute values of the absolute position signal and the torque signal, a vehicle speed sensor acquires a vehicle speed signal of the target vehicle, and the absolute value of the absolute position signal and the vehicle speed signal are used as target data of the target vehicle, wherein the absolute position signal refers to a deviation angle between steering wheel rotating angles and a middle position (0 position) of the steering wheel when the vehicle moves forwards and straightly, and the absolute position signal can be a positive value or a negative value according to different left and right directions of the steering wheel.

Step S11: the ECU determines whether a chassis imbalance fault occurs in the target vehicle based on the target data.

Step S12: when the target vehicle has a chassis imbalance fault, the target assistance torque is calculated according to a predefined rule to control the motor to output the target assistance torque and is applied to the electric power steering system to balance the steering wheel torque.

Step S13: and triggering and outputting the fault zone bit and storing the fault zone bit, the target data and the target auxiliary torque.

In some embodiments of the present invention, when the above four conditions are simultaneously satisfied, it is determined that the target vehicle has a chassis imbalance fault, and when one of the above four conditions is not satisfied, it is determined that the target vehicle has no chassis imbalance fault. When the chassis imbalance fault occurs in the target vehicle, the state value of the output fault symptom flag (output fault flag) of the fault symptom determination module may be set to 1, and if the state value of the output fault symptom flag of the fault symptom determination module is set to 0. The output failure flag bit 1 is stored in a Non-Volatile Memory (NVM), and the output failure flag bit freeze data is stored, or target data on 5 consecutive program execution cycles when the output failure flag bit is 1 may be stored, and the target data includes, but is not limited to, an absolute value of a steering wheel absolute position signal, an absolute value of a steering wheel torque signal, a vehicle speed signal, and the like.

Step S14: and carrying out fault diagnosis on the chassis unbalance fault again. In some embodiments of the present invention, the purpose of calculating the target assist torque and applying the target assist torque to the steering wheel is to reduce the torque of the steering wheel by calculating the target assist torque to apply to the electric power steering system when the vehicle has a chassis imbalance fault, so that when the vehicle has a chassis imbalance fault, a driver of the vehicle drives the vehicle to run straight at a medium-high speed, and the holding force of the driver on the steering wheel is reduced, thereby improving the driving comfort and safety of the vehicle.

In some embodiments of the present invention, the purpose of diagnosing the chassis imbalance fault again is to diagnose and confirm the chassis imbalance fault again by the ECU when the chassis imbalance fault occurs. The diagnosis confirms that the unbalanced degree of the vehicle chassis of the unbalanced chassis fault is deep (the unbalanced chassis fault can be set as a primary fault), the calculated target torque is applied to the steering wheel to reduce the torque of the steering wheel, the user experience is improved, in order to further reduce the subsequent damage degree of the vehicle, the chassis is overhauled for a vehicle user to go to a vehicle maintenance shop in time, fault alarm can be carried out through EPS, a driver of the vehicle is prompted to overhaul the vehicle chassis in time, if the price difference chassis suspension is unbalanced, if the tire is unbalanced, and the like, and the vehicle chassis is maintained as required, if the chassis suspension is maintained, the tire is replaced, four-wheel positioning is carried out again, and the like. If the vehicle chassis imbalance degree of the chassis imbalance fault is shallow (the chassis imbalance fault can be set as a secondary fault), the vehicle can be inspected and maintained without going to a maintenance shop.

The method comprises the following specific steps: if the user selects the enabling of the CMCD function, the user intention of the CMCD enabled user is converted into a software flag bit related to the CMCD enabling in the ECU of the EPS and is set, if the user sets the CMCD to be in a forbidden state through the human-computer interface, the function of fault diagnosis of the unbalanced fault of the chassis is not enabled again, the CMCD forbids the user intention, and the ECU in the EPS clears the software flag bit related to the CMCD enabling, wherein the related software flag bit refers to a switch variable in software, and the state of the switch variable corresponds to the user intention of the CMCD enabling. The switch variable is 1 if the user intention is enable, and 0 if the user intention is not enable.

In some embodiments of the present invention, in order to ensure that the software flag bit of the CMCD is lost when the vehicle is in the off state, the software flag bit of the CMCD may be stored in the NVM, so that even if the vehicle is in the off state, the software flag bit can be continuously maintained as the setting intention of the user on the "CMCD" based on the human-computer interface, and when the user resets the CMCD through the human-computer interface, the state of the corresponding software flag bit may be changed again.

In some embodiments of the invention, the fault diagnosing the chassis imbalance fault again comprises:

and if so, judging that the chassis imbalance fault is a primary fault.

If not, judging that the chassis unbalance fault is a secondary fault.

Specifically, in some embodiments of the present invention, on the premise that the CMCD mode is enabled and a chassis imbalance fault occurs, if the target assist torque exceeds a threshold (a torque diagnosis threshold, obtained according to actual vehicle calibration) and continues for a predetermined time (the predetermined time may be actually measured, for example, the predetermined time may be 5 seconds or 10 seconds), when the above two conditions are met simultaneously, it indicates that the vehicle chassis imbalance degree is deep, i.e., a primary fault. In order to avoid the condition deterioration of the vehicle, the vehicle can be overhauled at an automobile repair shop, and if the target assistance torque does not exceed the threshold value, the vehicle chassis unbalance degree is low (namely, secondary failure) and the vehicle does not need to be overhauled at the automobile repair shop.

Specifically, in some embodiments of the present invention, if the fault diagnosis is confirmed, the fault warning lamp is turned on, the fault code, the freeze data associated with the fault code, and the environment variable data are stored in the NVM, and the stored fault code can be read by the external diagnostic device. If a user finds out fault alarm, and timely maintains and eliminates chassis unbalanced faults such as chassis suspension and the like, the chassis unbalanced fault is repaired at the moment, the output of the target power-assisted torque is zero, if the chassis unbalanced fault of the vehicle disappears, a fault alarm lamp is turned off, a fault output marker position is zero, fault code information is cleared through an external fault diagnosis instrument, wherein after the fault code means that a fault occurs, EPS (electric power system) software can detect the fault and store the fault in the form of a code, and the diagnosis instrument can read the code of the fault so as to know what fault occurs, what the fault meaning is, and frozen data and environment variables mean: at the moment the fault occurs, some data useful for fault analysis is captured and stored. For example: engine status, mileage, battery voltage, etc., and an external diagnostic device refers to an external tool device, such as a laptop computer running specific interface software, for communicating with the vehicle electronic control system to read fault codes or for other purposes.

In some embodiments of the present invention, if the enabling flag of the CMCD is displayed as true (controlled by the user through the human-machine interface), performing fault diagnosis again on the chassis imbalance fault may also include:

and if the absolute value of the target assistance torque is larger than the difference between the maximum torque limit and the relief control torque threshold, if so, the chassis unbalance fault does occur, a fault flag of the chassis unbalance fault is set, a fault alarm lamp is turned on, a state bit of a fault code of the chassis unbalance fault is set to be 1, a status bit of the chassis unbalance fault is set to be 1, an aging calculator of the fault code is set to be zero, a state bit of the fault code is set to be 1, fault code indicator required is set to be 1, and fault code fault management data (comprising stored value environment variables, fault freezing data and the like) are recorded in the NVM.

Where the maximum torque limit is a comparison threshold for diagnostics, determined either empirically or through real-vehicle calibration, testfailedthiesmonitoringcycle, indicating the monitored cycle fault occurred, configredtc indicating a confirmed fault code, and agiingcounter, indicating an aging counter whose value, if not zero, is 10, assuming no fault has occurred for 10 consecutive drive cycles (i.e., firing cycles). The WarningIndicator request indicates that a fault alert is requested. The threshold value of the release control torque needs to be calibrated in real vehicles, the basis of calibration is related to subjective steering hand feeling, and the threshold value of the release control torque is determined according to the steering hand feeling.

If the absolute value of the target assistance torque is smaller than the difference between the maximum torque limit and the mitigation control torque threshold value, the fault flag bit of the chassis imbalance fault is cleared, the fault warning lamp is turned off, the testfailedthismonitorcyclein the fault code of the chassis imbalance fault is set to 0, the configeddtc in the status bit is kept to 1, the fault code aging calculator aging Counter is set to zero, and the warningindicative request in the status bit of the fault code is set to 0.

If the enable flag bit of the CMCD shows false, the above failure diagnosis confirmation is not performed.

The embodiment of the invention discloses another chassis unbalance fault monitoring method based on an electric power steering system, which is characterized in that whether a target vehicle has a chassis unbalance fault or not is judged through target data related to the target vehicle, and when the chassis has the chassis unbalance fault, a target assistance torque is calculated according to a predefined rule to control a motor to output the target assistance torque and is applied to the electric power steering system so as to balance the steering wheel torque. Therefore, after the target power-assisted torque is applied to the electric power-assisted steering system, the steering wheel torque applied to the electric power-assisted steering system by a user can be reduced, the hand torque of the driver acting on the steering wheel is small, the extreme fatigue of the driver is avoided, the problem that the hand of the user is separated from the steering wheel due to the overlarge holding force of the steering wheel is also avoided, and safety accidents are avoided.

In addition, the fault marker bit, the target data and the target torque assisting are stored in the NVM, a driver is reminded to go to a vehicle maintenance shop to overhaul a vehicle chassis in time through the fault alarm lamp, troubleshooting is facilitated by means of data in the NVM, and safety of the automobile is improved.

Furthermore, fault diagnosis is performed on the vehicle chassis fault again, so that the light weight and the heavy weight of the vehicle chassis fault are distinguished, a driver can conveniently maintain the adaptability, and the vehicle maintenance efficiency is improved.

Referring to fig. 4, fig. 4 is a schematic structural diagram of an electric power steering control system according to an embodiment of the present invention, the electric power steering system includes:

an acquisition module 40 for acquiring target data of a target vehicle, the target data describing steering wheel related data of the target vehicle and vehicle speed related data of the target vehicle;

the judging module 50 is used for judging whether the target vehicle has a chassis imbalance fault or not based on the target data, and if the target vehicle has the chassis imbalance fault, entering the control module;

and the control module 60 is used for calculating a target assist torque according to a predefined rule to control the motor to output the target assist torque and apply the target assist torque to the electric power steering system so as to balance the steering wheel torque.

Further, the embodiment of the invention also discloses an automobile which comprises the electric power steering control system.

According to the electric power steering system and the automobile disclosed by the embodiment of the invention, whether the target vehicle has chassis unbalance fault or not is judged through target data related to the target vehicle, and when the chassis unbalance fault occurs, a target power assisting moment is calculated according to a predefined rule to control the motor to output the target power assisting moment and is applied to the electric power steering system so as to balance the moment of a steering wheel. So, after applying the target moment of assistance on electric power steering system, can reduce the user and apply the steering wheel moment in electric power steering system, driver's hand moment of acting on the steering wheel is little, has avoided the driver extremely tired, has also avoided the user to lead to the problem that the hand breaks away from the steering wheel because of the too big power of holding of steering wheel, avoids taking place the incident.

What should be noted later is: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A chassis imbalance fault monitoring method based on an electric power steering system is characterized by comprising the following steps:

obtaining target data of a target vehicle, the target data describing steering wheel related data of the target vehicle and vehicle speed related data of the target vehicle; the target data includes: an absolute value of a steering wheel absolute position signal of the target vehicle, an absolute value of a steering wheel torque signal of the target vehicle, and a vehicle speed signal of the target vehicle;

the determining whether the target vehicle has a chassis imbalance fault based on the target data comprises:

a fourth condition: controlling a counter to accumulate when the first condition, the second condition and the third condition are simultaneously met in a preset period, wherein the accumulated value of the counter reaches a target value;

if the target vehicle has the chassis unbalance fault, calculating a target auxiliary torque according to a predefined rule to control a motor to output the target auxiliary torque and apply the target auxiliary torque to the electric power steering system so as to balance the steering wheel torque; wherein,

if the absolute value of the steering wheel torque signal is greater than a second torque threshold, calculating the target assist torque comprises:

if the sum value is between an upper limit value and a lower limit value, taking the sum value as the target assistance torque;

if the absolute value of the steering wheel torque signal does not exceed a second torque threshold, calculating the target assist torque comprises:

2. The method of monitoring for a chassis imbalance fault based on an electric power steering system of claim 1, further comprising:

3. The method for monitoring a chassis imbalance fault based on an electric power steering system according to claim 2, further comprising:

and carrying out fault diagnosis on the chassis unbalance fault again.

4. The method for monitoring a chassis imbalance fault based on an electric power steering system according to claim 3, wherein performing fault diagnosis again on the chassis imbalance fault comprises:

if yes, judging that the chassis unbalance fault is a primary fault;

and if not, judging that the chassis unbalance fault is a secondary fault.

5. An electric power steering control system characterized by comprising:

an acquisition module to acquire target data of a target vehicle, the target data describing steering wheel related data of the target vehicle and vehicle speed related data of the target vehicle; the target data includes: an absolute value of a steering wheel absolute position signal of the target vehicle, an absolute value of a steering wheel torque signal of the target vehicle, and a vehicle speed signal of the target vehicle;

a judging module, configured to judge whether a chassis imbalance fault occurs in the target vehicle based on the target data, where the judging whether the chassis imbalance fault occurs in the target vehicle based on the target data includes:

if the target vehicle has the chassis imbalance fault, entering a control module;

the control module is used for calculating a target assisting moment according to a predefined rule so as to control a motor to output the target assisting moment and apply the target assisting moment to the electric power steering system so as to balance the moment of a steering wheel; wherein,

if the sum is between an upper limit value and a lower limit value, taking the sum as the target moment of assistance;

6. An automobile, comprising: the electric power steering control system of claim 5.