CN110588634A - Vehicle speed control method and system in turning scene and vehicle - Google Patents

Vehicle speed control method and system in turning scene and vehicle Download PDF

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Publication number
CN110588634A
CN110588634A CN201910849365.4A CN201910849365A CN110588634A CN 110588634 A CN110588634 A CN 110588634A CN 201910849365 A CN201910849365 A CN 201910849365A CN 110588634 A CN110588634 A CN 110588634A
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vehicle
wheel
front wheels
compensation amount
front wheel
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CN110588634B (en
Inventor
李弼超
孙崇尚
张超昱
陈集辉
赵永正
李想
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Guangzhou Xiaopeng Motors Technology Co Ltd
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Guangzhou Xiaopeng Motors Technology Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/02—Control of vehicle driving stability
    • B60W30/04—Control of vehicle driving stability related to roll-over prevention
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2520/00—Input parameters relating to overall vehicle dynamics
    • B60W2520/10—Longitudinal speed
    • B60W2520/105—Longitudinal acceleration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2520/00—Input parameters relating to overall vehicle dynamics
    • B60W2520/20—Sideslip angle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2530/00—Input parameters relating to vehicle conditions or values, not covered by groups B60W2510/00 or B60W2520/00
    • B60W2530/20—Tyre data
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2720/00—Output or target parameters relating to overall vehicle dynamics
    • B60W2720/10—Longitudinal speed

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  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Control Of Driving Devices And Active Controlling Of Vehicle (AREA)

Abstract

The embodiment of the invention relates to the technical field of automobiles, and discloses a method and a system for controlling vehicle speed in a turning scene, and a vehicle, wherein the method comprises the following steps: obtaining the lateral force applied to the front wheel of the vehicle according to the obtained slip angle of the front wheel of the vehicle; acquiring longitudinal force applied to a front wheel of a vehicle; according to the target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force received by the wheels of the vehicle, the lateral force received by the front wheels of the vehicle and the longitudinal force, the driving force compensation amount required to be increased when the front wheels of the vehicle turn is obtained; the vehicle wheel comprises a vehicle front wheel and a vehicle rear wheel; determining wheel end torque value compensation quantity of the front wheels of the vehicle according to the driving force compensation quantity; determining a feedforward term according to the wheel end torque value compensation quantity; the feedforward term is fed back to a vehicle speed controller of the vehicle, so that the vehicle speed controller controls the vehicle to run according to a preset vehicle speed when the vehicle turns, and the running speed of the vehicle can be controlled and stabilized when the vehicle turns, so that the vehicle is prevented from being out of control.

Description

Vehicle speed control method and system in turning scene and vehicle
Technical Field
The invention relates to the technical field of automobiles, in particular to a method and a system for controlling vehicle speed in a turning scene and a vehicle.
Background
With the rapid development of automobile manufacturing technology, automatic driving of automobiles is gradually becoming a research and development object of automobile manufacturers. In the automatic driving of the automobile, in order to control the automobile to travel along a target path or track and enable the automobile to meet index requirements such as comfort and safety, automobile manufacturers design a vehicle speed controller to control and stabilize the traveling speed of the automobile.
In practice, it is found that when an automobile turns at a large angle, the running speed of the automobile is suddenly changed, and the traditional automobile speed controller cannot accurately control and stabilize the running speed of the automobile, so that the automobile may lose control, and an automobile accident is caused.
Disclosure of Invention
The embodiment of the invention discloses a vehicle speed control method and system in a turning scene and a vehicle, which can control and stabilize the running speed of the vehicle when the vehicle turns so as to avoid the vehicle from being out of control.
The first aspect of the embodiment of the invention discloses a vehicle speed control method in a turning scene, which comprises the following steps:
obtaining a lateral force applied to a front wheel of the vehicle according to the obtained slip angle of the front wheel of the vehicle;
acquiring longitudinal force applied to the front wheels of the vehicle;
according to a target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the wheels of the vehicle, the lateral force and the longitudinal force, acquiring the driving force compensation amount required to be increased when the front wheels of the vehicle turn; the vehicle wheels include the vehicle front wheels and vehicle rear wheels;
determining wheel end torque value compensation quantity of the front wheels of the vehicle according to the driving force compensation quantity;
determining a feedforward term according to the wheel end torque value compensation quantity;
and feeding the feedforward term back to a vehicle speed controller of the vehicle so that the vehicle speed controller controls the vehicle to run according to a preset vehicle speed when the vehicle turns.
As an alternative implementation, in the first aspect of the embodiment of the present invention, the acquiring a longitudinal force applied to a front wheel of the vehicle includes:
calculating the longitudinal force applied to the front wheel of the vehicle according to the wheel end torque of a driving motor of the vehicle, the tire radius of the front wheel of the vehicle and the following formula:
wherein, F islfRepresents a longitudinal force to which the vehicle front wheel is subjected, the T represents a wheel end torque of a drive motor of the vehicle, and the r represents a tire radius of the vehicle front wheel.
As an alternative implementation, in the first aspect of the embodiment of the present invention, the obtaining of the driving force compensation amount that needs to be increased when the front wheel of the vehicle turns according to the target correspondence relationship between the acceleration of the longitudinal movement of the vehicle and the resultant force to which the vehicle wheel is subjected, the lateral force, and the longitudinal force includes:
calculating the driving force compensation amount required to be increased when the front wheels of the vehicle turn according to a target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the wheels of the vehicle, the lateral force, the longitudinal force and the combination formula, namely:
wherein, F iscomIndicating a need for increased drive of the front wheels of the vehicle during corneringAmount of force compensation, said FlfRepresenting a longitudinal force experienced by the vehicle front wheels, f (α f) representing a lateral force experienced by the vehicle front wheels, α f representing a yaw angle of the vehicle front wheels, δ f representing a yaw angle of the vehicle front wheels, m representing a mass of the vehicle, mRepresenting the speed of lateral movement of the vehicle, theRepresenting the yaw rate of said vehicle, said Flf(1-cos δ f) represents a loss value of the longitudinal drive torque of the front wheel of the vehicle, and f (α f) sin δ f represents a resistance component due to the lateral force of the front wheel of the vehicle.
As an alternative implementation, in the first aspect of the embodiment of the present invention, the determining a wheel-end torque value compensation amount of the front wheels of the vehicle based on the driving force compensation amount includes:
calculating the wheel end torque value compensation quantity of the front wheel of the vehicle according to the driving force compensation quantity, the tire radius of the front wheel of the vehicle and the following formula, namely:
Tsteer＝Fcom*r
wherein, T issteerRepresenting the amount of compensation of the wheel end torque value of the front wheels of the vehicle, said FcomIndicating that the vehicle front wheel requires an increased driving force compensation amount while turning, and r indicating the tire radius of the vehicle front wheel.
As an alternative implementation, in the first aspect of the embodiment of the present invention, the determining a feed-forward term according to the wheel-end torque value compensation amount includes:
calculating a feedforward term according to the wheel end torque value compensation amount, the preset ramp compensation amount, the preset wind resistance compensation amount and the preset rolling resistance compensation amount and by combining the following formulas, namely:
Tff＝b(FR+FL+FS)+Tsteer
wherein, T isffRepresenting the feedforward term, b representing a preset known coefficient, FRRepresents the preset rolling resistance compensation amount, FLRepresenting the preset windage compensation amount, FSRepresents the preset hill compensation amount, TsteerAnd represents the wheel end torque value compensation amount of the front wheels of the vehicle.
The second aspect of the embodiment of the present invention discloses a vehicle speed control system in a turning scene, including:
a first obtaining unit, configured to obtain a lateral force to which a front wheel of a vehicle is subjected, based on an obtained slip angle of the front wheel;
a second obtaining unit configured to obtain a longitudinal force to which the front wheels of the vehicle are subjected;
a third obtaining unit, configured to obtain a driving force compensation amount that needs to be increased when the front wheel of the vehicle turns, according to a target correspondence relationship between an acceleration of a longitudinal motion of the vehicle and a resultant force to which a wheel of the vehicle is subjected, the lateral force, and the longitudinal force; the vehicle wheels include the vehicle front wheels and vehicle rear wheels;
a first determination unit configured to determine a wheel-end torque value compensation amount of the front wheels of the vehicle based on the driving force compensation amount;
the second determining unit is used for determining a feedforward term according to the wheel end torque value compensation quantity;
and the feedback unit is used for feeding the feedforward term back to a vehicle speed controller of the vehicle so that the vehicle speed controller controls the vehicle to run according to a preset vehicle speed when the vehicle turns.
As an optional implementation manner, in the second aspect of the embodiment of the present invention, the manner in which the second obtaining unit obtains the longitudinal force received by the front wheel of the vehicle is specifically:
a second obtaining unit, configured to calculate a longitudinal force to which the vehicle front wheel is subjected, based on a wheel end torque of a drive motor of the vehicle, a tire radius of the vehicle front wheel, and in combination with the following formula:
wherein, F islfRepresents a longitudinal force to which the vehicle front wheel is subjected, the T represents a wheel end torque of a drive motor of the vehicle, and the r represents a tire radius of the vehicle front wheel.
As an alternative implementation, in the second aspect of the embodiment of the present invention, the third obtaining unit obtains the driving force compensation amount that needs to be increased when the front wheel of the vehicle turns, according to the target correspondence relationship, the lateral force, and the longitudinal force, specifically:
a third obtaining unit, configured to calculate, according to the target correspondence relationship, the lateral force, the longitudinal force, and in combination with the following formula, a driving force compensation amount that needs to be increased when the front wheel of the vehicle turns, that is:
wherein, F iscomA driving force compensation amount indicating that the front wheels of the vehicle need to be increased at the time of turning, said FlfRepresenting a longitudinal force experienced by the vehicle front wheels, f (α f) representing a lateral force experienced by the vehicle front wheels, α f representing a yaw angle of the vehicle front wheels, δ f representing a yaw angle of the vehicle front wheels, m representing a mass of the vehicle, mRepresenting the speed of lateral movement of the vehicle, theRepresenting the yaw rate of said vehicle, said Flf(1-cos δ f) represents a loss value of the longitudinal drive torque of the front wheel of the vehicle, and f (α f) sin δ f represents a resistance component due to the lateral force of the front wheel of the vehicle.
As an alternative implementation, in the second aspect of the embodiment of the present invention, the first determining unit determines the wheel-end torque value compensation amount of the front wheels of the vehicle according to the driving force compensation amount by:
a first determination unit for calculating a wheel-end torque value compensation amount for the vehicle front wheel, based on the driving force compensation amount, a tire radius of the vehicle front wheel, and in combination with the following formula:
Tsteer＝Fcom*r
wherein, T issteerRepresenting the amount of compensation of the wheel end torque value of the front wheels of the vehicle, said FcomIndicating that the vehicle front wheel requires an increased driving force compensation amount while turning, and r indicating the tire radius of the vehicle front wheel.
As an alternative implementation, in the second aspect of the embodiment of the present invention, the manner in which the second determining unit determines the feedforward term according to the wheel-end torque value compensation amount is specifically:
the second determining unit is used for calculating a feedforward term according to the wheel end torque value compensation amount, the preset slope compensation amount, the preset wind resistance compensation amount, the preset rolling resistance compensation amount and the combination of the following formula, namely:
Tff＝b(FR+FL+FS)+Tsteer
wherein, T isffRepresenting the feedforward term, b representing a preset known coefficient, FRRepresents the preset rolling resistance compensation amount, FLRepresenting the preset windage compensation amount, FSRepresents the preset hill compensation amount, TsteerAnd represents the wheel end torque value compensation amount of the front wheels of the vehicle.
The third aspect of the embodiment of the invention discloses a vehicle speed control system in a turning scene, which comprises:
a memory storing executable program code;
a processor coupled with the memory;
the processor calls the executable program code stored in the memory to execute the vehicle speed control method under the turning scene disclosed by the first aspect of the embodiment of the invention.
A fourth aspect of the embodiments of the present invention discloses a computer-readable storage medium storing a computer program, wherein the computer program causes a computer to execute a method for controlling a vehicle speed in a turning scene disclosed in the first aspect of the embodiments of the present invention.
A fifth aspect of the embodiments of the present invention discloses a computer program product, which, when running on a computer, causes the computer to perform part or all of the steps of any one of the methods of the first aspect of the embodiments of the present invention.
A sixth aspect of the present embodiment discloses an application publishing platform, where the application publishing platform is configured to publish a computer program product, where when the computer program product runs on a computer, the computer is caused to perform part or all of the steps of any one of the methods in the first aspect of the present embodiment.
A seventh aspect of the embodiment of the invention discloses a vehicle including the vehicle speed control system in a turning scene disclosed in the second aspect of the embodiment of the invention.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, a vehicle speed control system in a turning scene can acquire a target corresponding relation between the acceleration of the longitudinal motion of a vehicle and the resultant force on the wheels of the vehicle, determine the wheel end torque value compensation quantity which needs to be increased when the front wheels of the vehicle turn on the basis of the target corresponding relation, and determine a feedforward item of a vehicle speed controller by combining the environmental factors which need to be considered in the actual running of the vehicle such as the slope compensation quantity, the wind resistance compensation quantity, the rolling main force compensation quantity and the like of the vehicle; the feedforward term is fed back to a vehicle speed controller of the vehicle, and the vehicle speed controller which can still stably work when the vehicle turns can be obtained. Compared with the traditional vehicle speed controller, the vehicle speed controller added with the feedforward term considers the driving force compensation amount required to be increased when the front wheels of the vehicle turn, so that the vehicle speed controller added with the feedforward term can control and stabilize the running speed of the vehicle when the vehicle turns, and the vehicle can be prevented from being out of control.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a flow chart illustrating a method for controlling vehicle speed in a turning situation according to an embodiment of the present disclosure;
FIG. 2 is a flow chart illustrating a method for controlling vehicle speed during another turning scenario in accordance with the disclosure;
FIG. 3 is a schematic structural diagram of a vehicle speed control system in a turning scene according to an embodiment of the disclosure;
FIG. 4 is a schematic diagram of a vehicle speed control system in another turning scenario as disclosed in the embodiments of the present invention;
FIG. 5 is a schematic structural diagram of a vehicle speed control system in a turning scene according to another embodiment of the disclosure;
fig. 6 is a schematic diagram for assisting in explaining the difference between the longitudinal direction of the vehicle and the x-axis direction, according to the embodiment of the present invention.
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 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.
It is to be noted that the terms "first", "second" and "third" etc. in the description and claims of the present invention are used for distinguishing different objects, and are not used for describing a specific order. The terms "comprises," "comprising," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus 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 apparatus.
The embodiment of the invention discloses a vehicle speed control method and system in a turning scene and a vehicle, which can control and stabilize the running speed of the vehicle when the vehicle turns so as to avoid the vehicle from being out of control.
The technical solution of the present invention will be described in detail with reference to specific examples.
Example one
Referring to fig. 1, fig. 1 is a flowchart illustrating a method for controlling a vehicle speed in a turning scene according to an embodiment of the present invention. As shown in fig. 1, the vehicle speed control method in the turning scene may include the steps of:
101. and the vehicle speed control system under the turning scene obtains the lateral force applied to the front wheel of the vehicle according to the obtained slip angle of the front wheel of the vehicle.
In the embodiment of the invention, the vehicle speed control method under the turning scene can be suitable for front wheel steering and front wheel drive vehicles; in other alternative embodiments, the vehicle speed control method in the turning scene may also be applied to a front-wheel steering and rear-wheel driving vehicle, or a front-wheel steering and front-wheel driving vehicle, and the embodiments of the present invention are not limited; the embodiment of the present invention is described by taking a front-wheel steering and front-wheel drive vehicle as an example, and the embodiment of the present invention should not be limited thereto.
In the embodiment of the invention, a vehicle speed control system under a turning scene can acquire a plurality of groups of experimental data, and each group of experimental data at least comprises a slip angle alpha F of any vehicle front wheel and a lateral force F corresponding to each slip anglecf(i.e., the lateral forces to which the front wheels of the vehicle are subjected), it should be noted that: the multiple groups of experimental data can be obtained by testing the vehicle speed control system in the same place and by using the same vehicle in a turning scene.
Furthermore, the vehicle speed control system in the turning scene can obtain the functional relationship between the slip angle of the front wheel of the vehicle and the lateral force applied to the front wheel of the vehicle by an interpolation method according to the plurality of groups of experimental data, namely:
Fcf＝f(αf)
wherein, FcfWhich represents the lateral force experienced by the front wheels of the vehicle, and alphaf represents the slip angle of the front wheels of the vehicle.
It needs to be further explained that: the interpolation method is also called "interpolation method" in which a function value of a function f (x) at a certain known point in a certain interval is used to generate an appropriate specific function, and the value of the specific function is used as an approximate value of the function f (x) at other points in the interval.
102. The vehicle speed control system under the turning scene obtains the longitudinal force that the vehicle front wheel received.
As an alternative embodiment, the way that the vehicle speed control system obtains the longitudinal force applied to the front wheel of the vehicle according to the moment balance relationship of the front wheel of the vehicle in the turning scene can be as follows: the vehicle speed control system in a turning scene calculates the longitudinal force applied to the front wheel of the vehicle according to the wheel end torque of a driving motor of the vehicle, the tire radius of the front wheel of the vehicle and the combination of the following formula, namely:
wherein, FlfWhich represents the longitudinal force to which the front wheels of the vehicle are subjected, T represents the wheel end torque of the drive motor of the vehicle, and r represents the tire radius of the front wheels of the vehicle.
It should be noted that: since the embodiment of the present invention is described by taking a vehicle with front wheel steering and front wheel driving as an example, the front wheels of the vehicle are also driving wheels of the vehicle, that is, the wheel end torque of the driving motor of the vehicle acts on the front wheels of the vehicle, so the vehicle speed control system in a turning scene can obtain the longitudinal force received by the front wheels of the vehicle according to the moment balance relation of the front wheels of the vehicle.
By implementing the method, the vehicle speed control system in the turning scene can obtain the longitudinal force applied to the front wheel of the vehicle according to the moment balance relation of the front wheel of the vehicle, and because only the wheel end torque of the driving motor of the vehicle and the tire radius of the front wheel of the vehicle are needed through the moment balance relation, the data can be collected simply and conveniently, and the difficulty in collecting the specific numerical value of the longitudinal force applied to the front wheel of the vehicle is further reduced.
103. The vehicle speed control system under the turning scene obtains the driving force compensation amount which needs to be increased when the front wheels of the vehicle turn according to the target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force on the wheels of the vehicle, the lateral force on the front wheels of the vehicle and the longitudinal force on the front wheels of the vehicle, wherein the wheels of the vehicle comprise the front wheels of the vehicle and the rear wheels of the vehicle.
In the embodiment of the invention, the vehicle speed control system in the turning scene can obtain the target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the wheels of the vehicle through a vehicle dynamics single-track model, namely:
where m represents the mass of the vehicle,the acceleration representing the longitudinal movement of the vehicle,indicating the speed of the lateral movement of the vehicle,representing the yaw rate of the vehicle, FxfRepresenting the resultant force, F, experienced by the front wheels of the vehicle in the x-axis directionxrIndicating the resultant force experienced by the rear wheels of the vehicle in the x-axis direction.
What needs to be explained in conjunction with fig. 6 is that: the longitudinal direction and the lateral direction of the vehicle are defined based on the position of the vehicle, and the x-axis direction of the vehicle is the direction pointed by the x-axis of a coordinate system established according to a preset origin O; as shown in fig. 6, since the vehicle is not parallel to the x-axis, the longitudinal direction of the vehicle is not the same as the x-axis direction, and similarly, the lateral direction of the vehicle is not the same as the y-axis direction; that is, the longitudinal direction of the vehicle is not equivalent to the x-axis direction, and they are not related; similarly, the lateral direction of the vehicle is not related to the y-axis direction.
The vehicle speed control system under the turning scene can obtain the resultant force F of the front wheels of the vehicle in the x-axis direction according to the stress balance analysisxfThe conversion relationship between the lateral force and the longitudinal force to which the front wheels of the vehicle are subjected is as follows:
Fxf＝Flfcosδf-Fcfsinδf
wherein, FxfRepresenting the resultant force, F, experienced by the front wheels of the vehicle in the x-axis directionlfRepresenting the longitudinal force to which the front wheels of the vehicle are subjected, FcfIndicating the lateral force to which the front wheels of the vehicle are subjected, and δ f the yaw angle of the front wheels of the vehicle.
The vehicle speed control system under the turning scene can obtain the resultant force F of the rear wheel of the vehicle in the x-axis direction according to the stress balance analysisxrThe conversion relationship between the lateral force and the longitudinal force to which the rear wheels of the vehicle are subjected is as follows:
Fxr＝Flrcosδr-Fcrsinδr
wherein, FxrRepresenting the resultant force, F, experienced by the rear wheel of the vehicle in the x-axis directionlrRepresenting the longitudinal force to which the rear wheels of the vehicle are subjected, FcrIndicating the lateral force experienced by the rear wheels of the vehicle and δ r the yaw angle of the rear wheels of the vehicle.
F is to bexf＝Flfcosδf-Fcfsin δ F and Fxr＝Flrcosδr-Fcrsubstitution of sin δ rThat is, the target correspondence between the acceleration of the longitudinal movement of the vehicle and the resultant force to which the wheels of the vehicle are subjected can be expressed as:
wherein, m is shown inThe mass of the vehicle is indicated and,the acceleration representing the longitudinal movement of the vehicle,indicating the speed of the lateral movement of the vehicle,representing the yaw rate of the vehicle, FlfRepresenting the longitudinal force to which the front wheels of the vehicle are subjected, FcfIndicating the lateral force to which the front wheels of the vehicle are subjected, FlrRepresenting the longitudinal force to which the rear wheels of the vehicle are subjected, FcrIndicating the lateral force to which the rear wheels of the vehicle are subjected, δ f indicating the yaw angle of the front wheels of the vehicle, δ r indicating the yaw angle of the rear wheels of the vehicle.
Since the embodiment of the present invention is described by taking a front-wheel-steering and front-wheel-drive vehicle as an example, the rear wheels of the vehicle are not steered, that is, the yaw angle δ r of the rear wheels of the vehicle is 0 °, and F in the target correspondence relationship can be determinedlrcosδr＝Flr，Fcrsin δ r is 0; and substituting the lateral force received by the front wheel of the vehicle obtained in the step 102 and the longitudinal force received by the front wheel of the vehicle obtained in the step 103 into the target corresponding relationship, and simplifying the target corresponding relationship, namely, the driving force compensation amount required to be increased when the front wheel of the vehicle turns can be obtained.
As an alternative embodiment, the vehicle speed control system in the turning scene may obtain the driving force compensation amount required to be increased when the front wheels of the vehicle turn according to the target corresponding relation, the lateral force applied to the front wheels of the vehicle, and the longitudinal force applied to the front wheels of the vehicle, by: the vehicle speed control system under the turning scene calculates the driving force compensation amount which needs to be increased when the front wheels of the vehicle turn according to the target corresponding relation, the lateral force received by the front wheels of the vehicle, the longitudinal force received by the front wheels of the vehicle and the combination of the following formula, namely:
wherein, FcomIndicating an increased driving force compensation amount required for the front wheels of the vehicle during cornering, FlfRepresenting the longitudinal force to which the front wheels of the vehicle are subjected, f (alphaf) representing the lateral force to which the front wheels of the vehicle are subjected, alphaf representing the slip angle of the front wheels of the vehicle, deltaf representing the yaw angle of the front wheels of the vehicle, m representing the mass of the vehicle,indicating the speed of the lateral movement of the vehicle,representing the yaw rate of the vehicle, Flf(1-cos δ f) represents a loss value of the longitudinal drive torque of the front wheels of the vehicle, and f (α f) sin δ f represents a resistance component due to the lateral force of the front wheels of the vehicle.
By implementing the method, the vehicle speed control system in the turning scene can calculate the driving force compensation amount required to be increased when the front wheels of the vehicle turn according to the target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force received by the wheels of the vehicle, the lateral force received by the front wheels of the vehicle, the longitudinal force received by the front wheels of the vehicle and the characteristics of the front wheels of the vehicle, which are combined with the driving of the front wheels of the vehicle, and then a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle when the vehicle turns can be designed according to the driving force compensation amount.
104. And the vehicle speed control system under the turning scene determines the wheel end torque value compensation quantity of the front wheels of the vehicle according to the driving force compensation quantity.
In the embodiment of the invention, the vehicle speed control system in the turning scene can calculate the wheel end torque value compensation quantity corresponding to the driving force compensation quantity according to the moment balance relation, and the wheel end torque value compensation quantity is used as the wheel end torque value compensation quantity of the front wheels of the vehicle in the turning process.
As an alternative embodiment, the vehicle speed control system in the turning scene may determine the wheel end torque value compensation amount of the front wheels of the vehicle according to the driving force compensation amount by: the vehicle speed control system in a turning scene calculates the wheel end torque value compensation quantity of the front wheel of the vehicle according to the driving force compensation quantity, the tire radius of the front wheel of the vehicle and the following formula, namely:
Tsteer＝Fcom*r
wherein, TsteerRepresenting the amount of compensation of the torque value at the wheel end of the front wheel of the vehicle, FcomIndicating that the vehicle front wheel requires an increased driving force compensation amount while turning, and r indicates the tire radius of the vehicle front wheel.
By implementing the method, the vehicle speed control system in the turning scene can calculate the wheel end torque value compensation quantity corresponding to the driving force compensation quantity according to the moment balance relation, and the wheel end torque value compensation quantity is used as the wheel end torque value compensation quantity when the front wheels of the vehicle turn, so that a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle when the vehicle turns can be designed according to the wheel end torque value compensation quantity.
105. And the vehicle speed control system under the turning scene determines a feedforward term according to the wheel end torque value compensation quantity of the front wheels of the vehicle.
In the embodiment of the invention, the vehicle speed control system under the turning scene can determine the feedforward item which is more suitable for a vehicle speed controller according to the wheel end torque value compensation quantity of the front wheel of the vehicle and the environment factors (such as slope compensation, wind resistance compensation and rolling resistance compensation) required to be considered in the actual running of the vehicle.
As an alternative implementation, the vehicle speed control system in the turning scene may determine the feed-forward term according to the wheel end torque value compensation amount of the front wheel of the vehicle by: the vehicle speed control system under the turning scene calculates a feedforward term according to the wheel end torque value compensation quantity, the preset ramp compensation quantity, the preset wind resistance compensation quantity, the preset rolling resistance compensation quantity and the combination of the following formulas, namely:
Tff＝b(FR+FL+FS)+Tsteer
wherein, TffRepresenting a feedforward term, b representing a predetermined known coefficient, FRIndicating a preset rolling resistance compensation amount, FLIndicating a preset windage compensation quantity, FSIndicating a preset amount of hill compensation, TsteerRepresenting the amount of wheel-end torque value compensation for the front wheels of the vehicle.
It should be noted that: wherein, the preset windage compensation amount: fL＝0.5ρACxv2(ii) a Preset rolling resistance compensation amount:preset slope compensation amount: fS＝mg sinθ；
Wherein, FZRepresenting the vehicle weight; ρ represents an air density; a represents the frontal area of the vehicle; cxRepresents an air resistance coefficient; v represents the moving speed of the vehicle; f. ofR0Represents a rolling resistance 0 order coefficient; f. ofR1A coefficient of order 1 representing rolling resistance; f. ofR2A 4-order coefficient representing rolling resistance; m represents the mass of the vehicle; g represents a gravity constant; theta denotes the pitch angle of the vehicle (because FSThe vehicle gravity compensation of (1) is mainly dependent on the accuracy of the pitch angle fed back by the vehicle attitude estimation).
It needs to be further explained that: the preset known coefficients are: b is R/R
Where b represents a predetermined known coefficient, R represents the radius of the vehicle wheel, and R represents the reduction ratio from the vehicle motor end to the vehicle wheel end transmission system.
That is, the preset known coefficient b can be directly obtained from the power transmission of the vehicle and the tire arrangement of the vehicle wheels, and is therefore known.
By implementing the method, the vehicle speed control system in the turning scene can further consider that environmental factors (such as slope compensation, wind resistance compensation and rolling resistance compensation) need to be considered in the actual running of the vehicle so as to determine a feedforward item more suitable for a vehicle speed controller, and then a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle during turning of the vehicle can be designed according to the feedforward item.
106. The vehicle speed control system under the turning scene feeds the feedforward item back to a vehicle speed controller of the vehicle, so that the vehicle speed controller controls the vehicle to run according to the preset vehicle speed when the vehicle turns.
In the embodiment of the invention, the vehicle speed control system in the turning scene can feed back the feedforward term to the vehicle speed controller of the vehicle, and the vehicle speed controller can be a PI feedback controller (namely a proportional and integral feedback controller). That is, after the PI feedback controller adds the determined feedforward term, a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle when the vehicle turns can be obtained, so that the vehicle speed controller controls the vehicle to run at a preset vehicle speed when the vehicle turns.
It can be seen that, by implementing the method described in fig. 1, the vehicle speed control system in the turning scene may obtain a target corresponding relationship between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the vehicle wheels, determine the wheel end torque value compensation amount that needs to be increased when the front wheels of the vehicle turn based on the target corresponding relationship, and determine the feed-forward term of the vehicle speed controller in combination with the environmental factors that need to be considered in the actual running of the vehicle, such as the ramp compensation amount, the wind resistance compensation amount, and the rolling main force compensation amount of the vehicle; and feeding the feedforward term back to a vehicle speed controller of the vehicle to obtain the vehicle speed controller which can still stably work when the vehicle turns. Compared with the traditional vehicle speed controller, the vehicle speed controller added with the feedforward term considers the driving force compensation amount required to be increased when the front wheels of the vehicle turn, so that the vehicle speed controller added with the feedforward term can control and stabilize the running speed of the vehicle when the vehicle turns, and the vehicle can be prevented from being out of control.
Example two
Referring to fig. 2, fig. 2 is a flow chart illustrating another method for controlling a vehicle speed in a turning scene according to an embodiment of the disclosure. As shown in fig. 2, the vehicle speed control method in the turning scene may include the steps of:
201. the vehicle speed control system in a turning scene calculates the slip angle of the front wheels of the vehicle according to the lateral speed of the wheels of the vehicle and the longitudinal speed of the wheels of the vehicle.
In the embodiment of the invention, the vehicle speed control system in the turning scene can be used for controlling the lateral speed v of the vehicle wheelcSpeed v of the vehicle wheel in the longitudinal directionlAnd calculating the slip angle of the front wheels of the vehicle by combining the following formula:
αf＝tan-1(vc/vl)
wherein alpha isfIndicating the slip angle, v, of the front wheels of the vehiclecIndicating the speed of the vehicle wheel in the lateral direction, vlRepresenting the speed of the vehicle wheel in the longitudinal direction.
It should be noted that: due to the speed v of the vehicle wheels in the lateral directioncAnd the speed v of the vehicle wheel in the longitudinal directionlIs difficult to directly acquire, so the vehicle speed v in the x-axis direction of the vehicle can be obtainedxfAnd the vehicle speed v in the y-axis directionyf(to be further explained is vcAnd vlExpressed as the speed of the wheel, and vxfAnd vyfExpressed as the running speed of the vehicle), the speed v of the vehicle wheels in the lateral direction is obtainedcNamely: v. ofc＝vyfcosδf-vxfsin δ f; and obtaining the speed v of the vehicle wheel in the longitudinal directionlNamely: v. ofl＝vyfsinδf+vxfcos δ f; and because ofAndthe slip angle of the front wheels of the vehicle can be calculated, namely:
wherein alpha isfIndicating the slip angle of the front wheels of the vehicle,indicating the speed of the lateral movement of the vehicle,which is indicative of the speed of longitudinal movement of the vehicle,representing the yaw rate of the vehicle, a representing the center of mass of the vehicle toDistance of front axle, δfRepresenting the yaw angle of the front wheels of the vehicle.
202. And the vehicle speed control system under the turning scene obtains the lateral force applied to the front wheel of the vehicle according to the obtained slip angle of the front wheel of the vehicle.
203. The vehicle speed control system under the turning scene obtains the longitudinal force that the vehicle front wheel received.
204. The vehicle speed control system under the turning scene obtains the driving force compensation amount which needs to be increased when the front wheels of the vehicle turn according to the target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force on the wheels of the vehicle, the lateral force on the front wheels of the vehicle and the longitudinal force on the front wheels of the vehicle, wherein the wheels of the vehicle comprise the front wheels of the vehicle and the rear wheels of the vehicle.
205. And the vehicle speed control system under the turning scene determines the wheel end torque value compensation quantity of the front wheels of the vehicle according to the driving force compensation quantity.
206. And the vehicle speed control system under the turning scene determines a feedforward term according to the wheel end torque value compensation quantity of the front wheels of the vehicle.
207. The vehicle speed control system under the turning scene feeds the feedforward item back to a vehicle speed controller of the vehicle, so that the vehicle speed controller controls the vehicle to run according to the preset vehicle speed when the vehicle turns.
It can be seen that, compared to the implementation of the method described in fig. 1, the vehicle speed control system in a cornering scenario can also calculate the slip angle of the front wheels of the vehicle according to the speed of the wheels in the lateral direction and the speed of the wheels in the longitudinal direction of the vehicle; and the lateral speed of the vehicle wheel and the longitudinal speed of the vehicle wheel are difficult to directly acquire, so that the vehicle speed control system in a turning scene can determine the lateral speed of the vehicle wheel and the longitudinal speed of the vehicle wheel according to the running speed of the vehicle, and the acquisition difficulty of the slip angle of the front wheel of the vehicle is reduced.
EXAMPLE III
Referring to fig. 3, fig. 3 is a schematic structural diagram of a vehicle speed control system in a turning scene according to an embodiment of the disclosure. Referring to fig. 3, the vehicle speed control system in the turning scene may include:
a first obtaining unit 301 for obtaining a lateral force to which a front wheel of the vehicle is subjected, based on the obtained slip angle of the front wheel of the vehicle;
a second obtaining unit 302, configured to obtain a longitudinal force applied to a front wheel of the vehicle according to a moment balance relationship of the front wheel of the vehicle;
a third obtaining unit 303, configured to obtain a driving force compensation amount that needs to be increased when the front wheel of the vehicle turns, according to the target correspondence relationship, the lateral force applied to the front wheel of the vehicle, and the longitudinal force applied to the front wheel of the vehicle;
a first determination unit 304 for determining a wheel-end torque value compensation amount for the front wheels of the vehicle based on the driving force compensation amount;
a second determination unit 305 for determining a feed-forward term according to the wheel end torque value compensation amount;
and a feedback unit 306 for feeding back the feedforward term to a vehicle speed controller of the vehicle, so that the vehicle speed controller controls the vehicle to run at a preset vehicle speed when turning.
It can be seen that, by implementing the system described in fig. 3, a target corresponding relationship between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the wheels of the vehicle can be obtained, the wheel end torque value compensation amount required to be increased when the front wheels of the vehicle turn is determined based on the target corresponding relationship, and the feedforward term of the vehicle speed controller is determined by combining the slope compensation amount, the wind resistance compensation amount, the rolling main force compensation amount and other environmental factors which are required to be considered in the actual running of the vehicle; the feedforward term is fed back to a vehicle speed controller of the vehicle, and the vehicle speed controller which can still stably work when the vehicle turns can be obtained. Compared with the traditional vehicle speed controller, the vehicle speed controller added with the feedforward term considers the driving force compensation amount required to be increased when the front wheels of the vehicle turn, so that the vehicle speed controller added with the feedforward term can control and stabilize the running speed of the vehicle when the vehicle turns, and the vehicle can be prevented from being out of control.
Example four
Referring to fig. 4, fig. 4 is a schematic structural diagram of a vehicle speed control system in another turning scene according to the disclosure of the embodiment of the invention. The vehicle speed control system in the turning situation shown in fig. 4 is optimized from the vehicle speed control system in the turning situation shown in fig. 3. Compared to the vehicle speed control system in the turning situation shown in fig. 3, the vehicle speed control system in the turning situation shown in fig. 4 may further include:
a calculation unit 307 for calculating a slip angle of the front wheels of the vehicle, including the front wheels of the vehicle, based on the speed of the vehicle wheels in the lateral direction and the speed of the vehicle wheels in the longitudinal direction.
As an alternative embodiment, the manner in which the second obtaining unit 302 obtains the longitudinal force applied to the front wheel of the vehicle according to the moment balance relationship of the front wheel of the vehicle may specifically be:
a second obtaining unit 302, configured to calculate a longitudinal force to which the vehicle front wheel is subjected according to a wheel end torque of a driving motor of the vehicle, a tire radius of the vehicle front wheel, and a combination of the following formula:
wherein, FlfWhich represents the longitudinal force to which the front wheels of the vehicle are subjected, T represents the wheel end torque of the drive motor of the vehicle, and r represents the tire radius of the front wheels of the vehicle.
By implementing the method, the vehicle speed control system in the turning scene can obtain the longitudinal force applied to the front wheel of the vehicle according to the moment balance relation of the front wheel of the vehicle, and because only the wheel end torque of the driving motor of the vehicle and the tire radius of the front wheel of the vehicle are needed through the moment balance relation, the data can be collected simply and conveniently, and the difficulty in collecting the specific numerical value of the longitudinal force applied to the front wheel of the vehicle is further reduced.
As an alternative embodiment, the third obtaining unit 303 may specifically obtain, according to the target correspondence relationship, the lateral force applied to the front wheel of the vehicle, and the longitudinal force applied to the front wheel of the vehicle, the driving force compensation amount that needs to be increased when the front wheel of the vehicle turns:
a third obtaining unit 303, configured to calculate a driving force compensation amount that needs to be increased when the front wheel of the vehicle turns, according to the target correspondence relationship, the lateral force applied to the front wheel of the vehicle, the longitudinal force applied to the front wheel of the vehicle, and a combination of the following formula:
wherein, FcomIndicating an increased driving force compensation amount required for the front wheels of the vehicle during cornering, FlfRepresenting the longitudinal force to which the front wheels of the vehicle are subjected, f (alphaf) representing the lateral force to which the front wheels of the vehicle are subjected, alphaf representing the slip angle of the front wheels of the vehicle, deltaf representing the yaw angle of the front wheels of the vehicle, m representing the mass of the vehicle,indicating the speed of the lateral movement of the vehicle,representing the yaw rate of the vehicle, Flf(1-cos δ f) represents a loss value of the longitudinal drive torque of the front wheels of the vehicle, and f (α f) sin δ f represents a resistance component due to the lateral force of the front wheels of the vehicle.
By implementing the method, the vehicle speed control system in the turning scene can calculate the driving force compensation amount required to be increased when the front wheels of the vehicle turn according to the target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force received by the wheels of the vehicle, the lateral force received by the front wheels of the vehicle, the longitudinal force received by the front wheels of the vehicle and the characteristics of the front wheels of the vehicle, which are combined with the driving of the front wheels of the vehicle, and then a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle when the vehicle turns can be designed according to the driving force compensation amount.
As an alternative embodiment, the way that the first determining unit 304 determines the wheel-end torque value compensation amount of the front wheels of the vehicle according to the driving force compensation amount may specifically be:
a first determination unit 304 for calculating a wheel end torque value compensation amount for the front wheels of the vehicle, based on the driving force compensation amount, the tire radius of the front wheels of the vehicle, and in combination with the following formula:
Tsteer＝Fcom*r
wherein, TsteerRepresenting the amount of compensation of the torque value at the wheel end of the front wheel of the vehicle, FcomIndicating the amount of driving force compensation that the front wheels of the vehicle need to increase while turning, and r indicates the tire radius of the front wheels of the vehicle.
By implementing the method, the vehicle speed control system in the turning scene can calculate the wheel end torque value compensation quantity corresponding to the driving force compensation quantity according to the moment balance relation, and the wheel end torque value compensation quantity is used as the wheel end torque value compensation quantity when the front wheels of the vehicle turn, so that a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle when the vehicle turns can be designed according to the wheel end torque value compensation quantity.
As an alternative embodiment, the second determining unit 305 determines the feedforward term according to the wheel end torque value compensation amount by:
a second determining unit 305, configured to calculate a feed-forward term according to the wheel end torque value compensation amount, the preset slope compensation amount, the preset wind resistance compensation amount, the preset rolling resistance compensation amount, and a combination of the following formulas:
Tff＝b(FR+FL+FS)+Tsteer
wherein, TffRepresenting a feedforward term, b representing a predetermined known coefficient, FRIndicating a preset rolling resistance compensation amount, FLIndicating a preset windage compensation quantity, FSIndicating a preset amount of hill compensation, TsteerRepresenting the amount of wheel-end torque value compensation for the front wheels of the vehicle.
By implementing the method, the vehicle speed control system in the turning scene can further consider that environmental factors (such as slope compensation, wind resistance compensation and rolling resistance compensation) need to be considered in the actual running of the vehicle so as to determine a feedforward item more suitable for a vehicle speed controller, and then a vehicle speed controller capable of controlling and stabilizing the running speed of the vehicle during turning of the vehicle can be designed according to the feedforward item.
It can be seen that, compared with the system described in fig. 3, the system described in fig. 4 can calculate the slip angle of the front wheel of the vehicle according to the lateral speed of the vehicle wheel and the longitudinal speed of the vehicle wheel, thereby reducing the difficulty in obtaining the slip angle of the front wheel of the vehicle.
EXAMPLE five
Referring to fig. 5, fig. 5 is a schematic structural diagram of a vehicle speed control system in a turning scene according to another embodiment of the disclosure. As shown in FIG. 5, the vehicle speed control system in the turning scene may include:
a memory 501 in which executable program code is stored;
a processor 502 coupled to a memory 501;
the processor 502 calls the executable program code stored in the memory 501 to execute the vehicle speed control method in the turning scene of any one of fig. 1 and 2.
The embodiment of the invention discloses a computer-readable storage medium which stores a computer program, wherein the computer program enables a computer to execute a vehicle speed control method under a turning scene in any one of the figures 1 or 2.
The embodiment of the present invention also discloses an application publishing platform, wherein the application publishing platform is used for publishing a computer program product, and when the computer program product runs on a computer, the computer is caused to execute part or all of the steps of the method in the above method embodiments.
The embodiment of the invention also discloses a vehicle which comprises the vehicle speed control system under any turning scene disclosed by the embodiment of the invention.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Those skilled in the art should also appreciate that the embodiments described in this specification are exemplary and alternative embodiments, and that the acts and modules illustrated are not required in order to practice the invention.
In various embodiments of the present invention, it should be understood that the sequence numbers of the above-mentioned processes do not imply an inevitable order of execution, and the execution order of the processes should be determined by their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated units, if implemented as software functional units and sold or used as a stand-alone product, may be stored in a computer accessible memory. Based on such understanding, the technical solution of the present invention, which is a part of or contributes to the prior art in essence, or all or part of the technical solution, can be embodied in the form of a software product, which is stored in a memory and includes several requests for causing a computer device (which may be a personal computer, a server, a network device, or the like, and may specifically be a processor in the computer device) to execute part or all of the steps of the above-described method of each embodiment of the present invention.
It will be understood by those skilled in the art that all or part of the steps in the methods of the embodiments described above may be implemented by instructions associated with a program, which may be stored in a computer-readable storage medium, where the storage medium includes Read-Only Memory (ROM), Random Access Memory (RAM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), One-time Programmable Read-Only Memory (OTPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), compact disc-Read-Only Memory (CD-ROM), or other Memory, magnetic disk, magnetic tape, or magnetic tape, Or any other medium which can be used to carry or store data and which can be read by a computer.
The vehicle speed control method and system in the turning scene and the vehicle disclosed in the embodiments of the present invention are described in detail above, and the principle and the implementation manner of the present invention are explained in this document by applying specific examples, and the description of the above embodiments is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims (10)

1. A method of controlling vehicle speed in a turning scenario, the method comprising:
obtaining a lateral force applied to a front wheel of the vehicle according to the obtained slip angle of the front wheel of the vehicle;
acquiring longitudinal force applied to the front wheels of the vehicle;
according to a target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the wheels of the vehicle, the lateral force and the longitudinal force, acquiring the driving force compensation amount required to be increased when the front wheels of the vehicle turn; the vehicle wheels include the vehicle front wheels and vehicle rear wheels;
determining wheel end torque value compensation quantity of the front wheels of the vehicle according to the driving force compensation quantity;
determining a feedforward term according to the wheel end torque value compensation quantity;
and feeding the feedforward term back to a vehicle speed controller of the vehicle so that the vehicle speed controller controls the vehicle to run according to a preset vehicle speed when the vehicle turns.
2. The method of claim 1, wherein said acquiring longitudinal forces to which the front wheels of the vehicle are subjected comprises:
calculating the longitudinal force applied to the front wheel of the vehicle according to the wheel end torque of a driving motor of the vehicle, the tire radius of the front wheel of the vehicle and the following formula:
wherein, F islfRepresents a longitudinal force to which the vehicle front wheel is subjected, the T represents a wheel end torque of a drive motor of the vehicle, and the r represents a tire radius of the vehicle front wheel.
3. The method according to claim 2, wherein the obtaining of the driving force compensation amount that the vehicle front wheel needs to be increased in turning, based on the target correspondence relationship between the acceleration of the vehicle longitudinal motion and the resultant force to which the vehicle wheel is subjected, the lateral force, and the longitudinal force, comprises:
calculating the driving force compensation amount required to be increased when the front wheels of the vehicle turn according to a target corresponding relation between the acceleration of the longitudinal motion of the vehicle and the resultant force applied to the wheels of the vehicle, the lateral force, the longitudinal force and the combination formula, namely:
wherein, F iscomA driving force compensation amount indicating that the front wheels of the vehicle need to be increased at the time of turning, said FlfRepresents a longitudinal force to which the front wheels of the vehicle are subjected, f (α f) represents a lateral force to which the front wheels of the vehicle are subjected, α f represents a slip angle of the front wheels of the vehicle, δ f represents a slip angle of the front wheels of the vehicleA yaw angle of a front wheel, m representing a mass of the vehicle, theRepresenting the speed of lateral movement of the vehicle, theRepresenting the yaw rate of said vehicle, said Flf(1-cos δ f) represents a loss value of the longitudinal drive torque of the front wheel of the vehicle, and f (α f) sin δ f represents a resistance component due to the lateral force of the front wheel of the vehicle.
4. The method according to claim 3, wherein said determining a wheel-end torque value compensation amount for the front wheels of the vehicle based on the driving force compensation amount comprises:
calculating the wheel end torque value compensation quantity of the front wheel of the vehicle according to the driving force compensation quantity, the tire radius of the front wheel of the vehicle and the following formula, namely:
Tsteer＝Fcom*r
wherein, T issteerRepresenting the amount of compensation of the wheel end torque value of the front wheels of the vehicle, said FcomIndicating that the vehicle front wheel requires an increased driving force compensation amount while turning, and r indicating the tire radius of the vehicle front wheel.
5. The method of claim 4, wherein determining a feed forward term based on the wheel end torque value compensation amount comprises:
calculating a feedforward term according to the wheel end torque value compensation amount, the preset ramp compensation amount, the preset wind resistance compensation amount and the preset rolling resistance compensation amount and by combining the following formulas, namely:
Tff＝b(FR+FL+FS)+Tsteer
wherein, T isffRepresenting the feedforward term, b representing a preset known coefficient, FRRepresents the preset rolling resistance compensation amount, FLRepresenting the preset windage compensation amount, FSRepresents the preset hill compensation amount, TsteerAnd represents the wheel end torque value compensation amount of the front wheels of the vehicle.
6. A vehicle speed control system in a turning scenario, the system comprising:
a first obtaining unit, configured to obtain a lateral force to which a front wheel of a vehicle is subjected, based on an obtained slip angle of the front wheel;
a second obtaining unit configured to obtain a longitudinal force to which the front wheels of the vehicle are subjected;
a third obtaining unit, configured to obtain a driving force compensation amount that needs to be increased when the front wheel of the vehicle turns, according to a target correspondence relationship between an acceleration of a longitudinal motion of the vehicle and a resultant force to which a wheel of the vehicle is subjected, the lateral force, and the longitudinal force; the vehicle wheels include the vehicle front wheels and vehicle rear wheels;
a first determination unit configured to determine a wheel-end torque value compensation amount of the front wheels of the vehicle based on the driving force compensation amount;
the second determining unit is used for determining a feedforward term according to the wheel end torque value compensation quantity;
and the feedback unit is used for feeding the feedforward term back to a vehicle speed controller of the vehicle so that the vehicle speed controller controls the vehicle to run according to a preset vehicle speed when the vehicle turns.
7. The system according to claim 6, characterized in that said second acquisition unit acquires the longitudinal force to which the front wheels of the vehicle are subjected in particular by:
a second obtaining unit, configured to calculate a longitudinal force to which the vehicle front wheel is subjected, based on a wheel end torque of a drive motor of the vehicle, a tire radius of the vehicle front wheel, and in combination with the following formula:
wherein, F islfRepresents a longitudinal force to which the vehicle front wheel is subjected, the T represents a wheel end torque of a drive motor of the vehicle, and the r represents a tire radius of the vehicle front wheel.
8. A vehicle characterized by comprising the vehicle speed control system in a turning situation according to any one of claims 6 or 7.
9. A vehicle speed control system in a turning scenario, the system comprising a memory storing executable program code, and a processor coupled to the memory; wherein the processor calls the executable program code stored in the memory to execute the vehicle speed control method in the turning scene according to any one of claims 1 to 5.
10. A computer-readable storage medium storing a computer program, wherein the computer program causes a computer to execute the vehicle speed control method in a turning scene according to any one of claims 1 to 5.
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