CN111301389A

CN111301389A - Vehicle posture adjusting method and device and vehicle

Info

Publication number: CN111301389A
Application number: CN202010090796.XA
Authority: CN
Inventors: 延仲毅; 汪典成; 刘国瑞; 张荡; 滕国刚; 邱剑
Original assignee: Zhejiang Geely Holding Group Co Ltd; Ningbo Geely Automobile Research and Development Co Ltd
Current assignee: Zhejiang Geely Holding Group Co Ltd; Ningbo Geely Automobile Research and Development Co Ltd
Priority date: 2020-02-13
Filing date: 2020-02-13
Publication date: 2020-06-19
Anticipated expiration: 2040-02-13
Also published as: CN111301389B

Abstract

The invention discloses a vehicle posture adjusting method, a vehicle posture adjusting device and a vehicle, wherein the method comprises the following steps: acquiring the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle in real time; acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle; acquiring a vehicle torque request value according to the expected target deviation value and the actual target deviation value; acquiring a lateral acceleration expected value and a lateral acceleration maximum value according to the vehicle speed, the actual lateral acceleration and the steering wheel angle; according to the actual lateral acceleration, the expected lateral acceleration value and the maximum lateral acceleration value, the vehicle torque request value is adjusted, and the vehicle is controlled to run according to the adjusted vehicle torque request value.

Description

Vehicle posture adjusting method and device and vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to a vehicle posture adjusting method and device and a vehicle.

Background

The recent development of the related art is the body Electronic Stability Program (ESP) in bosch, which monitors the steering angle of the steering wheel, the signals of the wheel speed sensor, the side slip sensor, the three-way acceleration sensor, etc., calculates the current vehicle information in the controller, and compares the current vehicle information with the preset data stored in the memory to estimate the current driving state of the vehicle. When the vehicle has the tendency of understeer, the system can apply braking force to the rear wheel on the inner side of the turn to help the vehicle to better steer; when the vehicle has a tendency to turn over, the system may apply a braking force to the front wheels on the outside of the turn, helping the vehicle resist turning.

However, in consideration of the cost for installing the ESP system, all vehicles are not equipped with the ESP system, and therefore, if the vehicle is not equipped with the ESP system, the vehicle cannot be actively controlled by software, so that the vehicle may have dangerous postures such as vehicle slip and sideslip, which may cause accidents.

Disclosure of Invention

In view of the above problems in the prior art, an object of the present invention is to provide a vehicle attitude adjusting method, device and vehicle, which can solve the problem that when the existing vehicle is not equipped with an ESP, dangerous attitudes such as vehicle slip and sideslip occur, and improve driving stability.

In order to solve the technical problems, the specific technical scheme of the invention is as follows:

in one aspect, the present invention provides a vehicle attitude adjustment method, including the steps of:

acquiring the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle in real time;

acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle;

acquiring a vehicle torque request value according to the expected target deviation value and the actual deviation value;

acquiring a lateral acceleration expected value and a lateral acceleration maximum value according to the vehicle speed, the actual lateral acceleration and the steering wheel angle;

and regulating the vehicle torque request value according to the actual lateral acceleration, the lateral acceleration expected value and the lateral acceleration maximum value, and controlling the vehicle to run according to the regulated vehicle torque request value.

Further, acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle comprises:

establishing a vehicle speed, an actual lateral acceleration and a vehicle expected target deviation value mapping table;

according to the vehicle speed and the actual lateral acceleration, looking up a table to obtain a vehicle speed expected target deviation value;

and acquiring the actual target deviation value of the vehicle speed according to the vehicle speed and the wheel speed of the vehicle.

Specifically, the vehicle actual target deviation value is a difference value between the wheel speed and the vehicle speed.

Further, acquiring a lateral acceleration expected value and a lateral acceleration maximum value according to the vehicle speed, the actual lateral acceleration and the steering wheel angle comprises:

the calculation formula of the expected value of the lateral acceleration is as follows:

the method comprises the following steps that A, B, A, B and E, wherein Aydes is a lateral acceleration expected value, L is a vehicle wheelbase, k is a vehicle stability coefficient, v is a vehicle speed, and theta is a tire roll angle corresponding to a steering wheel corner;

the maximum calculation formula of the lateral acceleration is as follows:

where Aymax is the maximum lateral acceleration, Fz is the vehicle vertical load, μ is the ground friction coefficient, m is the vehicle mass, and Ax is the actual lateral acceleration.

Further, adjusting the vehicle torque request value according to the actual lateral acceleration, the lateral acceleration expected value and the lateral acceleration maximum value, and controlling the vehicle to operate according to the adjusted vehicle torque request value comprises the following steps:

judging whether the expected lateral acceleration value reaches the maximum lateral acceleration value or not;

if so, reducing the torque request value to 0Nm according to a preset torque gradient for regulation;

if not, judging whether the actual lateral acceleration exceeds the expected lateral acceleration value;

if the torque is not exceeded, reducing the torque request value to 0Nm according to a preset torque gradient for regulation;

if the vehicle speed exceeds the preset speed, the vehicle outer front wheel is braked through PI control.

On the other hand, on the basis of the above-provided vehicle attitude adjustment method, the present invention also provides a vehicle attitude adjustment device, the device including:

the vehicle information acquisition module is used for acquiring the vehicle speed, the wheel speed and the actual lateral acceleration in real time;

the target deviation value acquisition module is used for acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle;

a torque request value acquisition module for acquiring a vehicle torque request value according to the expected target offset value and the actual offset value;

the lateral acceleration processing module is used for acquiring a lateral acceleration expected value and a lateral acceleration maximum value according to the vehicle speed, the actual lateral acceleration and the steering wheel angle;

and the torque output module is used for adjusting the vehicle torque request value according to the actual lateral acceleration, the lateral acceleration expected value and the lateral acceleration maximum value and controlling the vehicle to run according to the adjusted vehicle torque request value.

Further, the target deviation value obtaining module includes:

the mapping table establishing unit is used for establishing a mapping table of vehicle speed, actual lateral acceleration and expected target deviation value of the vehicle;

the vehicle speed expected target deviation value acquisition unit is used for looking up a table to acquire a vehicle speed expected target deviation value according to the vehicle speed and the actual lateral acceleration;

and the actual target deviation value acquiring unit of the vehicle speed is used for acquiring the actual target deviation value of the vehicle speed according to the vehicle speed and the wheel speed of the vehicle.

Specifically, the table is a preset vehicle speed and actual lateral acceleration-vehicle speed expected target deviation value table.

Further, the lateral acceleration processing module includes:

the lateral acceleration expected value calculation unit is used for obtaining a lateral acceleration expected value according to vehicle speed measurement and steering wheel rotation angles, and the lateral acceleration expected value calculation formula is as follows:

a maximum lateral acceleration calculation unit, configured to obtain a maximum lateral acceleration, where the maximum lateral acceleration calculation formula is:

Further, the torque output module includes:

the first judgment unit is used for judging whether the expected lateral acceleration value reaches the maximum lateral acceleration value or not;

the first output unit is used for reducing the torque request value to 0Nm for regulation according to a preset torque gradient when the expected lateral acceleration value reaches the maximum lateral acceleration value;

the second judgment unit is used for judging whether the actual lateral acceleration exceeds the expected lateral acceleration value or not when the expected lateral acceleration value does not reach the maximum lateral acceleration value;

the second output unit is used for reducing the torque request value to 0Nm for regulation according to a preset torque gradient when the actual lateral acceleration does not exceed the lateral acceleration expected value;

and a third output unit for braking the vehicle outside front wheel by PI control when the actual lateral acceleration does not exceed the lateral acceleration expected value.

In a third aspect, the present invention also provides a vehicle including a vehicle attitude adjustment apparatus as described above.

By adopting the technical scheme, the vehicle posture adjusting method, the vehicle posture adjusting device and the vehicle have the following beneficial effects:

1. according to the vehicle attitude adjusting method and device and the vehicle, the current state of the vehicle can be quickly estimated by combining the basic sensor signal with the wheel speed signal.

2. According to the vehicle attitude adjusting method, the vehicle attitude adjusting device and the vehicle, the table is looked up to determine the final control threshold value through the current vehicle speed and the lateral acceleration, and the slip rate is required to be controlled within a smaller range by the larger lateral acceleration, so that the driving stability of the vehicle is ensured.

3. According to the vehicle attitude adjusting method and device and the vehicle, the vehicle is prevented from deviating from the expected track in time through calculation and comparison of the expected lateral acceleration value and the maximum lateral acceleration value.

4. According to the vehicle attitude adjusting method, device and vehicle, dangerous attitudes such as vehicle sliding and sideslip are reduced, so that accidents can be greatly avoided.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiment or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a step diagram of a vehicle attitude adjustment method according to the present invention;

FIG. 2 is a schematic structural view of a vehicle attitude adjusting apparatus;

FIG. 3 is a schematic diagram of a structure of a target deviation value obtaining module shown in FIG. 1;

FIG. 4 is a schematic diagram of the lateral acceleration processing module of FIG. 1;

FIG. 5 is a schematic diagram of the torque output module of FIG. 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.

Example 1

In the case that an existing vehicle is not equipped with an Electronic Stability Program (ESP), the vehicle cannot be actively and safely controlled by software, so that dangerous postures such as slippage and sideslip occur to the vehicle, which may cause accidents.

Specifically, as shown in fig. 1, the vehicle attitude adjustment method includes the steps of:

s1: acquiring the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle in real time;

the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle can be obtained through a whole vehicle controller, and can also be obtained through arranging a plurality of sensors respectively.

S2: acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speed and the actual lateral acceleration of the vehicle;

the expected target deviation value of the vehicle is the best target deviation value obtained by the vehicle under the combined action of the actual lateral acceleration and the vehicle speed, and specifically, the target deviation value can be obtained by querying a preset table, for example, the target deviation value is determined by taking the actual lateral acceleration and the vehicle speed as two axes, for example, a larger lateral acceleration needs to control the slip ratio within a smaller range, so that a larger lateral adhesion coefficient of the tire is ensured; it should be noted that the table sets different calibration values according to different vehicle parameters.

The actual target deviation value is obtained by comparing an actual wheel speed and a vehicle speed, wherein the wheel speed is obtained by converting an individual tire rotating speed, the vehicle speed is an actual speed of a vehicle mass center calculated after comprehensive consideration, and generally, the actual target deviation value is a difference value between the wheel speed and the vehicle.

S3: acquiring a vehicle torque request value according to the expected target deviation value and the actual target deviation value;

since the expected target offset value and the actual target offset value are both changed in real time, the corresponding torque request value is also continuously changed during output, and the difference between the actual target offset value and the expected target offset value can be controlled through the PI, so that the torque request value is obtained.

S4: acquiring a lateral acceleration expected value and a lateral acceleration maximum value according to the vehicle speed, the actual lateral acceleration and the steering wheel angle;

the maximum value of the lateral acceleration is a limit value of the lateral acceleration of the vehicle, when the limit value is exceeded, the vehicle can generate accidents such as sideslip and the like, therefore, when the expected value of the lateral acceleration of the vehicle exceeds the maximum value of the lateral acceleration, the requested value of the torque of the vehicle is controlled and adjusted, and in order to improve the safety of vehicle control, the limit value can be set to be smaller than an actual limit value, namely, the control can be carried out when the expected value of the lateral acceleration is close to the maximum value of the lateral acceleration.

Specifically, the maximum value of the lateral acceleration is actually related to the friction coefficient of the vehicle, and the friction coefficient is generally related to the parameters of the vehicle, such as the rotational inertia of the wheel and its accessories, the angular velocity of the wheel, the total driving torque, the braking torque, the power radius of the wheel, the braking torque, the rolling resistance and the vehicle speed, and therefore is a real-time variation value, which can be obtained by setting a friction coefficient calculation module for real-time calculation.

In some embodiments, the lateral acceleration maximum calculation formula is:

And the expected lateral acceleration value is a lateral acceleration value which can be reached by the vehicle under the condition of the current acceleration change rate, and specifically, the expected lateral acceleration value is calculated according to the following formula:

s5: and regulating the vehicle torque request value according to the actual lateral acceleration, the lateral acceleration expected value and the lateral acceleration maximum value, and controlling the vehicle to run according to the regulated vehicle torque request value.

In some embodiments, it may be desirable to first compare the expected lateral acceleration value to the maximum lateral acceleration value to determine the vehicle condition, for example when the expected lateral acceleration value reaches or approaches the maximum lateral acceleration value, without requiring excessive torque adjustments to the vehicle, and therefore, it may be desirable to reduce the torque request value to 0Nm, or it may be desirable to gradually reduce the torque request value according to a calibrated torque gradient, for example, 10Nm/ms when the torque request value is 80Nm, and 8ms when the torque request value is 0 Nm.

In some embodiments, when the expected lateral acceleration value does not exceed or approach the maximum lateral acceleration value, the actual lateral acceleration and the expected lateral acceleration value need to be compared to determine whether the vehicle is steered insufficiently or oversteered, which is smaller than that when the actual lateral acceleration does not exceed the expected lateral acceleration value, which indicates that the actual lateral acceleration is smaller, and at this time, torque limitation is not needed to ensure that the actual lateral acceleration approaches the expected lateral acceleration value, so that the requested torque value is only reduced to 0Nm, which needs to be gradually reduced according to a calibrated torque gradient.

And when the actual lateral acceleration exceeds the expected lateral acceleration value, the actual lateral acceleration is larger, the vehicle is oversteered, and the steering control is needed.

In the above-mentioned adjusting method, the vehicle speed, the real-time lateral acceleration, etc. are all changed in real time, so the torque value is also changed in real time, and the judgment process involved therein is also performed at any time.

On the basis of the vehicle attitude adjustment method provided above, an embodiment of the present specification also provides a vehicle attitude adjustment apparatus, specifically, as shown in fig. 2 to 5, the apparatus including:

for example, the vehicle speed, the wheel speed and the actual lateral acceleration CAN be directly obtained by the vehicle control unit through vehicle instrument information.

The target deviation value acquisition module is used for acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speed and the actual lateral acceleration;

specifically, the expected target deviation value of the vehicle speed can be obtained through a preset table unit, for example, a mapping table of the vehicle speed, the actual lateral acceleration and the expected target deviation value of the vehicle is established through a mapping table establishing unit, and the table determines the target deviation value by taking the actual lateral acceleration and the vehicle speed as two axes, for example, a larger lateral acceleration needs to control the slip ratio within a smaller range, so as to ensure that the lateral adhesion coefficient of the tire is larger; it should be noted that the table sets different calibration values according to different vehicle parameters; and finally, acquiring a vehicle speed actual target deviation value according to the vehicle speed and the wheel speed of the vehicle by the vehicle speed actual target deviation value acquisition unit, wherein the vehicle speed actual target deviation value can be a calculation unit set by the vehicle.

the difference between the actual target offset value and the expected target offset value may be controlled by the PI to obtain the torque request value.

The lateral acceleration processing module is used for acquiring a lateral acceleration expected value and a lateral acceleration maximum value according to the vehicle speed, the actual lateral acceleration and a steering wheel corner;

wherein the vehicle acceleration processing module includes:

The torque output module includes:

It should be noted that the above mentioned computing modules or units can be implemented by a computing module preset in the vehicle control unit

An embodiment of the present specification also provides a vehicle provided with a vehicle attitude adjustment apparatus described above, which performs the method described above.

The vehicle posture adjusting method, the vehicle posture adjusting device and the vehicle have the following beneficial effects that:

1) according to the vehicle attitude adjusting method and device and the vehicle, the current state of the vehicle can be quickly estimated by combining the basic sensor signal with the wheel speed signal.

2) According to the vehicle attitude adjusting method, the vehicle attitude adjusting device and the vehicle, the table is looked up to determine the final control threshold value through the current vehicle speed and the lateral acceleration, and the slip rate is required to be controlled within a smaller range by the larger lateral acceleration, so that the driving stability of the vehicle is ensured.

3) According to the vehicle attitude adjusting method and device and the vehicle, the vehicle is prevented from deviating from the expected track in time through calculation and comparison of the expected lateral acceleration value and the maximum lateral acceleration value.

4) According to the vehicle attitude adjusting method, device and vehicle, dangerous attitudes such as vehicle sliding and sideslip are reduced, so that accidents can be greatly avoided.

While the invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the invention can be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A vehicle attitude adjustment method characterized by comprising the steps of:

acquiring a vehicle speed expected target deviation value and a vehicle speed actual target deviation value according to the vehicle speed, the wheel speeds and the actual lateral acceleration of the vehicle;

acquiring a vehicle torque request value according to the expected target deviation value and the actual target deviation value;

2. The vehicle attitude adjustment method according to claim 1, wherein obtaining a vehicle speed expected target deviation value and a vehicle speed actual target deviation value based on the vehicle speed, the wheel speed, and the actual lateral acceleration comprises:

and acquiring an actual target deviation value of the vehicle speed according to the vehicle speed and the wheel speed.

3. The vehicle attitude adjustment method according to claim 2, wherein acquiring a lateral acceleration desired value and a lateral acceleration maximum value based on the vehicle speed, the actual lateral acceleration, and a steering wheel angle comprises:

the maximum calculation formula of the lateral acceleration is as follows:

4. The vehicle attitude adjustment method according to claim 1, wherein adjusting the vehicle torque request value in accordance with the actual lateral acceleration, the lateral acceleration desired value, and the lateral acceleration maximum value, and controlling the vehicle operation in accordance with the adjusted vehicle torque request value includes:

5. A vehicle attitude adjusting apparatus, characterized by comprising:

6. The vehicle attitude adjusting apparatus according to claim 5, wherein the target deviation value acquiring means includes:

7. The vehicle attitude adjusting apparatus according to claim 6, wherein the tables are tables of preset vehicle speed and actual lateral acceleration-vehicle speed expected target deviation values.

8. The vehicle attitude adjustment device according to claim 5, characterized in that the lateral acceleration processing module includes:

9. The vehicle attitude adjustment device according to claim 5, characterized in that the torque output module includes:

10. A vehicle characterized by comprising a vehicle attitude adjustment apparatus according to any one of claims 5 to 9.