CN113335263B - Distributed four-wheel drive torque control method - Google Patents

Distributed four-wheel drive torque control method Download PDF

Info

Publication number
CN113335263B
CN113335263B CN202110814949.5A CN202110814949A CN113335263B CN 113335263 B CN113335263 B CN 113335263B CN 202110814949 A CN202110814949 A CN 202110814949A CN 113335263 B CN113335263 B CN 113335263B
Authority
CN
China
Prior art keywords
vehicle
wheel
axle
torque
speed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110814949.5A
Other languages
Chinese (zh)
Other versions
CN113335263A (en
Inventor
吴爱彬
张天强
刘元治
崔金龙
周泽慧
孙起春
赵洋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
FAW Group Corp
Original Assignee
FAW Group Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by FAW Group Corp filed Critical FAW Group Corp
Priority to CN202110814949.5A priority Critical patent/CN113335263B/en
Publication of CN113335263A publication Critical patent/CN113335263A/en
Application granted granted Critical
Publication of CN113335263B publication Critical patent/CN113335263B/en
Priority to PCT/CN2022/106240 priority patent/WO2023001100A1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/08—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of electric propulsion units, e.g. motors or generators
    • 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
    • B60W30/18—Propelling the vehicle
    • B60W30/182—Selecting between different operative modes, e.g. comfort and performance modes
    • 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
    • B60W40/02—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 related to ambient conditions
    • B60W40/06—Road conditions
    • B60W40/064—Degree of grip
    • 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
    • B60W40/02—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 related to ambient conditions
    • B60W40/06—Road conditions
    • B60W40/076—Slope angle of the road
    • 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
    • B60W40/10—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 related to vehicle motion
    • 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
    • B60W40/10—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 related to vehicle motion
    • B60W40/105—Speed
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Automation & Control Theory (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Arrangement And Driving Of Transmission Devices (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention belongs to the technical field of electric automobile drive control and discloses a distributed four-wheel drive torque control method which comprises the steps of firstly, obtaining current parameters of a vehicle; then calculating a reference vehicle speed, a vehicle acceleration, a road surface utilization adhesion coefficient and a road gradient; and calculating a running stability factor, selecting a vehicle working mode, and calculating four motor torques to realize distributed four-wheel drive torque control. Under the condition of considering the driving intention, the invention solves the problem of delay lag of the torque closed-loop control of the distributed four-wheel drive based on the vehicle stability operating state.

Description

Distributed four-wheel drive torque control method
Technical Field
The invention relates to the technical field of electric automobile drive control, in particular to a distributed four-wheel drive torque control method.
Background
At present, four-wheel drive control of an electric automobile mainly depends on vehicle states (such as wheel speed, steering wheel angle, yaw acceleration and the like) to carry out front and rear shaft torque distribution, so that functions of economic control, traction control and the like are realized, most of control does not fully consider recognition of driving intentions, and vehicle state acquisition depends on a sensor, is influenced by accuracy of sensor signals and transmission speed, and has the problem of response lag; meanwhile, the control method of the steering working condition mainly carries out closed-loop control mainly based on yaw feedback control through braking, has the problem of delay lag, and is single in control method and difficult to realize productization.
Disclosure of Invention
The invention aims to provide a distributed four-wheel drive torque control method to solve the problems of delay lag and no consideration of driving intention in distributed four-wheel drive torque control.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a distributed four-wheel drive torque control method, which comprises the following steps:
s1, acquiring the current parameters of the vehicle;
the current vehicle parameters comprise vehicle longitudinal acceleration, vehicle lateral acceleration, accelerator pedal opening, brake pedal opening, steering wheel angle, yaw rate, wheel speed and a current driver-selected vehicle operating mode;
s2, calculating a reference vehicle speed, a vehicle acceleration, a road adhesion coefficient, and a road gradient from the vehicle longitudinal acceleration, the vehicle lateral acceleration, the steering wheel angle, the yaw rate, and the wheel speed;
s3, calculating a driving stability factor according to the road adhesion coefficient, the vehicle acceleration, the reference vehicle speed and the steering wheel angle;
s4, selecting a vehicle working mode according to the accelerator pedal opening, the brake pedal opening, the reference vehicle speed, the steering wheel angle and the current vehicle operation mode;
the vehicle working modes are divided into three types, namely a movement working mode, an economic working mode and a braking working mode;
s5, when the vehicle is in any one of the motion working mode, the economy working mode and the brake working mode, four motor torques are calculated to realize distributed four-wheel drive torque control, and the specific calculation process is as follows:
(S51) when the current vehicle working mode of the electric vehicle is the movement working mode, performing dynamic analysis on the front and rear axle loads of the vehicle, considering the acceleration resistance and the gradient resistance of the vehicle, omitting the air resistance, the rolling resistance couple moment and the rotary inertia of the tire, and simplifying the axle load calculation of the front and rear axles into:
Figure BDA0003169831240000021
Figure BDA0003169831240000022
in the formula, Fzf，FzrVertical forces of the front and rear axles, m-vehicle mass, g-acceleration of gravity, hg-vehicle centre of mass height, ax-vehicle longitudinal acceleration, θ -ramp angle, a-front axle to vehicle center of mass distance, b-rear axle to vehicle center of mass distance, L ═ a + b denotes the wheelbase of the vehicle;
the road surface utilization adhesion coefficients of the front axle and the rear axle are respectively as follows:
Figure BDA0003169831240000023
Figure BDA0003169831240000024
in the formula, mufAnd murUsing the coefficient of adhesion, F, for the road surface of the front axle and the rear axle, respectivelyxfLongitudinal tire force of front axle, FxrLongitudinal tire force for the rear axle;
the road surface utilization adhesion coefficient of the front axle and the rear axle is equal, and the road surface utilization adhesion coefficient comprises the following components:
Figure BDA0003169831240000031
assuming an interaxial torque distribution coefficient lambda in said kinematic operating mode1Comprises the following steps:
Figure BDA0003169831240000032
neglecting the rolling resistance couple moment of the wheel, the motor driving torque T of the front and rear axlesf、TrLongitudinal loads F with front and rear axlesxf、FxrThe relationship of (1) is:
Figure BDA0003169831240000033
Figure BDA0003169831240000034
in the formula, rfRadius of the tire of the front axle, rrTire radius of rear axle, JfMoment of inertia of the front axle, Jr-the moment of inertia of the rear axle,
Figure BDA0003169831240000035
-the acceleration of the front axle,
Figure BDA0003169831240000036
-acceleration of the rear axle;
if the vehicle is in a constant speed or acceleration stable state, and inertia force generated by rotational inertia of a front shaft and a rear shaft is ignored, the following steps are provided:
Tr＝rrFxr
Tf＝rfFxf
thereby, the torque distribution coefficient lambda between the shafts1Expressed as:
Figure BDA0003169831240000037
when tan θ is equal to i and cos θ is equal to 1, there are,
Figure BDA0003169831240000038
according to the above formula, passing the road gradient i and the vehicle acceleration axObtaining the torque distribution coefficient lambda between the shafts1Then, the coaxial left and right motors are evenly distributed;
(S52) when the current vehicle operation mode of the electric vehicle is the economy operation mode, calculating the real-time power of the driving system according to the following formula:
Tr＝λ2·Ta
Tf＝(1-λ2)·Ta
Figure BDA0003169831240000041
Figure BDA0003169831240000042
Pall＝Pf+Pr
in the formula, TaIndicating driver demand torque, TfRepresenting front axle motor drive torque, TrRepresenting rear axle motor drive torque, λ2Representing the torque distribution coefficient between the shafts in the economy mode, n representing the motor speed, etaf、ηrRespectively, the operating efficiencies of the front and rear shaft motors, Pf，PrRespectively representing the output power, P, of the front and rear axle motorsallThe total output power of the front and rear shaft motors is represented, and the optimal control equation for obtaining the real-time power of the driving system according to the formula is as follows:
Figure BDA0003169831240000043
while the distributed torque requirements of the front and rear axles are limited by the available capacity of the assembly:
λ2·Ta≤Tmaxr
(1-λ2)·Ta≤Tmaxf
in the formula, TmaxrRepresenting the total available torque, T, of the rear axle motormaxfRepresenting the total available torque of the front axle motor;
according to the current driver required torque and the reference speed of the vehicle, the working efficiency of front and rear axle motors is combined, a torque distribution table with the optimal real-time power of a driving system is calculated in an off-line mode, so that the power loss of the current driving system of the whole vehicle is minimized, and the optimal inter-axle torque distribution coefficients in different reference speeds and driving torque states of the front and rear axle motors are calculated;
(S53) when the current vehicle operation mode of the electric vehicle is the brake operation mode, an inter-axle torque distribution coefficient λ in the brake operation moderearThe braking force distribution is realized on the front axle, limited by the following formula:
λrear＝min(0.5,λ2)。
optionally, the vehicle operating modes include a comfort operating mode, an economy operating mode, and a sport operating mode.
Optionally, the reference vehicle speed is obtained by:
normalizing the wheel speed of each wheel at the center of a rear axle;
Figure BDA0003169831240000051
Figure BDA0003169831240000052
Figure BDA0003169831240000053
Figure BDA0003169831240000054
in the formula (I), the compound is shown in the specification,
vflfor the longitudinal speed of the left front wheel, vfrLongitudinal speed of the right front wheel, vrlFor left rear wheel longitudinal speed, vrrIs the longitudinal speed of the right rear wheel, vfl_xLongitudinal speed, v, of the left front wheel at the center of the rear axlefr_xLongitudinal speed, v, of the right front wheel at the center of the rear axlerl_xLongitudinal speed, v, of the left rear wheel at the centre of the rear axlerr_xIs the longitudinal speed of the right rear wheel at the center of the rear axle, L is the vehicle wheelbase, b is the wheel moment, delta is the front wheel corner,
Figure BDA0003169831240000055
the yaw angular velocity;
the smallest normalized wheel speed is selected as the reference vehicle speed, i.e.:
vref_veh＝min(vfl_x,vfr_x,vrl_x,vrr_x)。
optionally, the vehicle acceleration aact：
Figure BDA0003169831240000056
Wherein the content of the first and second substances,
Figure BDA0003169831240000057
for reference vehicle speed vref_vehThe derivative of (c).
Alternatively, the road surface adhesion coefficient takes into account two cases:
if the drive slip is triggered, the road adhesion coefficient is updated with the current vehicle acceleration:
μ＝aact
if the driving antiskid function is not triggered, the road adhesion coefficient is updated to be the maximum value of the current vehicle acceleration and the road adhesion coefficient at the last moment:
μ＝max(aact，μ)
in the formula, vref_vehFor reference vehicle speed, μ is road adhesion coefficient, aactIs the vehicle acceleration.
Optionally, the road gradient i is:
Figure BDA0003169831240000061
wherein i represents a road gradient; a isxRepresenting the longitudinal acceleration measured by the sensor, g representing the gravitational acceleration, vxIndicating the longitudinal speed of the vehicle.
Optionally, the driving stability factor γ is as follows:
Figure BDA0003169831240000062
wherein gamma is a driving stability factor, fac1 and fac2 are factors related to a reference vehicle speed and a steering wheel angle respectively, and the values of the factors are between 0 and 1.
Optionally, the vehicle operation mode is divided by:
(1) the vehicle enters the sport mode of operation in any one of the following situations:
(1.1) the opening degree of an accelerator pedal is greater than a first preset opening degree;
(1.2) the opening degree of the accelerator pedal is greater than a second preset opening degree and smaller than a first preset opening degree, the change rate of the opening degree of the accelerator pedal is greater than a first preset value, and the received mode command is a comfortable operation mode command;
(1.3) the driving stability factor is greater than a set value and the received mode command is the comfort operation mode command;
(1.4) the road adhesion coefficient is smaller than a set value, and the received mode command is the comfort operation mode command;
(1.5) the road grade is greater than a set value and the received mode command is the comfort operation mode command;
(1.6) the received mode command is the sport operating mode command;
(2) entering the economy mode of operation in any one of:
(2.1) the opening degree of the accelerator pedal is greater than 0 and less than or equal to a second preset opening degree, and the received mode command is the comfortable operation mode command;
(2.2) the received mode command is the economy operation mode command;
(3) entering the braking mode of operation in any one of:
(3.1) the accelerator pedal opening is 0 and the received mode command is the comfort operation mode command;
and (3.2) the brake pedal opening degree signal is greater than 0.
Optionally, step S52 further includes a step of performing secondary optimization on the optimal inter-axis torque distribution coefficient, specifically:
the tolerance is defined as follows:
Figure BDA0003169831240000071
in the formula, Pall_bestRepresenting the total output power, P, corresponding to the optimal interaxial torque distribution coefficient at a certain operating pointall_TRepresenting the total output power with the tolerance constraint satisfied.
Optionally, the method further comprises torque distribution control of a steering condition, and the judgment condition of the steering condition is as follows:
(1) the opening degree of the accelerator pedal is greater than a set value A;
(2) the reference vehicle speed is greater than a set value B;
(3) the steering wheel angle is greater than a set value C; or the steering wheel rotating angle is larger than a set value D, and the steering wheel steering angular speed is larger than a set value E, wherein the set value D is smaller than the set value C;
when the three conditions are met simultaneously, the vehicle enters a steering working condition, and the control method of the forward movement of the axle load is adopted by the vehicle, and specifically comprises the following steps:
when the steering working condition is met, the front axle reduces the torque and has the duration of t1, and then reduces the torque and recovers the torque and has the duration of t1-t 2; the front axle torque is again reduced for a duration of t2-t3, then the torque reduction is resumed for a duration of t3-t4, … …, and so on, by a plurality of spaced front axle torque reductions, the vehicle axle load is advanced.
The invention has the beneficial effects that:
according to the distributed four-wheel-drive torque control method, under the condition that the driving intention is considered, the current working state of the vehicle is judged again by combining the current parameters of the vehicle, the torque required by a driver and the current vehicle operation mode to obtain three vehicle working modes, the four motor torques are calculated respectively, the calculation result is more accurate, and the problem of delay lag of torque closed-loop control of the distributed four-wheel-drive based on the stable operation state of the vehicle is solved.
Drawings
FIG. 1 is a schematic diagram of four motor distributions of a distributed four-wheel-drive electric vehicle;
FIG. 2 is a flow chart of a distributed four-wheel-drive torque control method provided by the present invention;
FIG. 3 is a schematic diagram illustrating the division of three vehicle operating modes in a distributed four-wheel-drive torque control method according to the present invention;
FIG. 4 is a schematic diagram of torque control under a steering condition in the distributed four-wheel-drive torque control method provided by the invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "right", etc. are used in an orientation or positional relationship based on that shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.
The invention provides a distributed four-wheel drive torque control method, wherein a distributed four-wheel drive electric vehicle comprises four motors, namely a left front motor, a left rear motor, a right front motor and a right rear motor which are respectively used for driving a left front wheel, a left rear wheel, a right front wheel and a right rear wheel as shown in figure 1, the four motors are uniformly controlled by a VCU (vehicle control unit) and perform steering, torque distribution and the like, and the problems of delay lag and no consideration of the intention of a driver in the conventional control method are solved.
It should be noted that, in the alphabetical parameters related to the present invention, the subscript x represents the longitudinal direction of the vehicle, y represents the lateral direction, z represents the vertical or vertical direction, f represents the front, such as the front wheel or the front axle, and r represents the rear, such as the rear wheel or the rear axle.
As shown in fig. 2, the distributed four-wheel drive torque control method provided by the present invention includes the following steps:
and S1, acquiring the current parameters of the vehicle.
The current parameters of the vehicle include vehicle longitudinal acceleration, vehicle lateral acceleration, accelerator pedal opening, brake pedal opening, steering wheel angle, yaw rate, wheel speed, and current driver-selected vehicle operating modes, including a comfort operating mode (also referred to as AUTO mode), an economy operating mode (also referred to as ECO mode), and a SPORT operating mode (also referred to as SPORT mode).
S2, a reference vehicle speed, a vehicle acceleration, a road surface attachment coefficient, and a road gradient are calculated from the vehicle longitudinal acceleration, the vehicle lateral acceleration, the steering wheel angle, the yaw rate, and the wheel speed.
And S3, calculating a driving stability factor according to the road adhesion coefficient, the vehicle acceleration, the reference vehicle speed and the steering wheel angle.
And S4, selecting a vehicle working mode according to the opening degree of an accelerator pedal, the opening degree of a brake pedal, the reference vehicle speed, the steering wheel angle and the current vehicle operation mode.
The vehicle operation mode is selected by a driver, the vehicle working modes are divided into three modes, namely a motion working mode, an economic working mode and a braking working mode, the vehicle operation mode is used for judging the current working state of the vehicle by the vehicle control unit, and more accurate motor torque can be obtained conveniently.
And S5, when the electric automobile is in any one of the motion working mode, the economy working mode and the braking working mode, four motor torques are calculated.
In the distributed four-wheel-drive torque control method, the intention identification of a driver is considered in the current parameters of the vehicle, the current running state of the vehicle in the vehicle operation mode is judged again, the new judgment mechanism comprises three vehicle working modes, the torques of four motors are respectively calculated in the three vehicle working modes, the distributed four-wheel-drive torque control is realized, the output torques of the four motors simultaneously consider the safety, the dynamic property and the economical property of the vehicle, the improvement of the steering performance of the vehicle is facilitated, and the driving assistance of the distributed four-wheel-drive control is realized.
Alternatively, the reference vehicle speed v in step S2ref_vehThe method is obtained by calculation according to the wheel speed, the yaw rate and the steering wheel angle, and specifically comprises the following steps:
normalizing the wheel speed of each wheel at the center of a rear axle;
Figure BDA0003169831240000111
Figure BDA0003169831240000112
Figure BDA0003169831240000113
Figure BDA0003169831240000114
in the formula (I), the compound is shown in the specification,
vflis the longitudinal speed (m/s), v, of the left front wheelfrThe longitudinal speed (m/s) of the right front wheel;
vrllongitudinal speed (m/s), v, of the left rear wheelrrIs the longitudinal speed (m/s) of the right rear wheel;
vfl_xlongitudinal vehicle speed (m/s), v, of the left front wheel at the center of the rear axlefr_xLongitudinal vehicle speed (m/s) at the center of the rear axle for the right front wheel;
vrl_xlongitudinal speed (m/s), v, of left rear wheel at center of rear axlerr_xLongitudinal vehicle speed (m/s) of the right rear wheel at the center of the rear axle;
l is the vehicle wheel base (m), b is the wheel moment (m), delta is the front wheel corner (rad),
Figure BDA0003169831240000115
the yaw rate (rad/s).
The smallest normalized wheel speed is selected as the reference vehicle speed, i.e.:
vref_veh＝min(vfl_x,vfr_x,vrl_x,vrr_x)
according to the reference vehicle speed
Figure BDA0003169831240000121
The vehicle acceleration a can be calculatedact：
Figure BDA0003169831240000122
Figure BDA0003169831240000123
For reference vehicle speed vref_vehDifferentiation of (2).
If the drive slip is triggered, the road adhesion coefficient is updated with the current vehicle acceleration:
μ＝aact
if the driving antiskid function is not triggered, the road adhesion coefficient is updated to be the maximum value of the current vehicle acceleration and the road adhesion coefficient at the last moment:
μ＝max(aact，μ)
in the formula, vref_vehFor reference vehicle speed, μ is road adhesion coefficient, aactIs the vehicle acceleration.
When the vehicle runs on a slope road, the sine value of the road slope i is the ratio of the difference value of the measured value of the longitudinal acceleration sensor and the longitudinal vehicle speed differential value to the gravity acceleration:
Figure BDA0003169831240000124
wherein i represents a road gradient; a isxLongitudinal addition representing sensor measurementsVelocity, g represents gravitational acceleration, in m/s2，vxIndicating the longitudinal speed of the vehicle.
Alternatively, in step S3, the running stability factor γ is mainly determined by the current vehicle acceleration aactAnd a road adhesion coefficient mu determined from a reference vehicle speed vref_vehAnd the steering wheel angle steeangle.
Figure BDA0003169831240000125
Wherein gamma is a driving stability factor, the value is between 0 and 1, and the larger the value is, the more fully the representation of the road surface is utilized, the closer the representation is to the road surface adhesion limit; fac1 and fac2 are factors relating to the reference vehicle speed and the steering wheel angle, respectively, and take values between 0 and 1.
Note that the driver required torque is a physical quantity relating to the accelerator opening and the reference vehicle speed, and the driver required torque is obtained by a calculation method in the related art in the embodiment of the invention, and therefore, a specific calculation process is not developed. Taking into account the driver demand torque (including the drive demand torque and the brake demand torque), it is convenient to divide the vehicle operating modes under the existing vehicle operating modes to provide a better torque distribution method.
In step S4, according to the current vehicle parameters in steps S1-S3, in conjunction with fig. 3, the three vehicle operation modes are divided as follows:
(1) the vehicle enters the motion working mode under the following conditions:
(1.1) the opening degree of an accelerator pedal is greater than a first preset opening degree;
(1.2) the opening degree of an accelerator pedal is greater than a second preset opening degree and smaller than a first preset opening degree, the opening degree change rate of the accelerator pedal is greater than a first preset value, and the received mode command is a comfortable operation mode command;
(1.3) the driving stability factor is larger than a set value, and the received mode command is a comfortable operation mode command;
(1.4) the road adhesion coefficient is smaller than a set value, and the received mode command is a comfortable operation mode command;
(1.5) the road gradient is greater than a set value, and the received mode command is a comfortable operation mode command;
(1.6) the received mode command is a sport operation mode command.
(2) The economic working mode is entered under the following two conditions:
(2.1) the opening degree of an accelerator pedal is greater than 0 and less than or equal to a second preset opening degree, and the received mode command is a comfortable operation mode command;
(2.2) the received vehicle operating mode command is an economy operating mode command.
(3) The brake working mode is entered under the following two conditions:
(3.1) the opening of the accelerator pedal is 0 and the received vehicle operation mode command is an automatic (or comfort) operation mode command;
and (3.2) the opening degree signal of the brake pedal is greater than 0.
In step S5, four motor torques are calculated in three vehicle operating modes, specifically as follows:
(S51) in the embodiment, when the current vehicle working mode of the electric vehicle is a motion working mode, torque distribution is carried out on the torque of each motor according to the optimal scheme of the power output of the whole vehicle, the road adhesion coefficient is fully utilized based on the vehicle axle load distribution, and the dynamic property is improved.
The dynamic analysis is carried out on the front axle load and the rear axle load of the vehicle, the acceleration resistance and the gradient resistance of the vehicle are considered, the factors such as air resistance, the rolling resistance couple moment of a tire, the rotary inertia and the like are omitted, and the axle load calculation of the front axle and the rear axle can be simplified as follows:
Figure BDA0003169831240000141
Figure BDA0003169831240000142
in the formula, Fzf，FzrVertical forces of the front and rear axles, m-vehicle mass, g-acceleration of gravity, hg-vehicle centre of mass height, ax-vehicle longitudinal acceleration, θ -ramp angle, a-front axle to vehicle center of mass distance, b-rear axle to vehicle center of mass distance, L ═ a + b denotes the wheelbase of the vehicle.
The road surface utilization adhesion coefficients of the front axle and the rear axle are respectively as follows:
Figure BDA0003169831240000143
Figure BDA0003169831240000144
in the formula, mufAnd murUsing the coefficient of adhesion, F, for the road surface of the front axle and the rear axle, respectivelyxfLongitudinal tire force of front axle, FxrIs the longitudinal tire force of the rear axle.
It should be noted that the road surface utilization adhesion coefficient is smaller than the road surface adhesion coefficient, which means the utilization rate of the road surface adhesion coefficient.
For promoting vehicle longitudinal drive stability, the road surface utilization adhesion coefficient of front axle and rear axle should equal as far as possible to reduce the total road surface adhesion coefficient of drive wheel, prevent that the drive wheel phenomenon of skidding from appearing too early, promptly:
Figure BDA0003169831240000151
inter-axle torque distribution coefficient lambda under assumption of motion working mode1Comprises the following steps:
Figure BDA0003169831240000152
neglecting the rolling resistance couple moment of the wheel, the motor driving torque T of the front and rear axlesf、TrLongitudinal load (longitudinal force) F with front and rear axlesxf、FxrThe relationship of (1) is:
Figure BDA0003169831240000153
Figure BDA0003169831240000154
in the formula, rfRadius of the tire of the front axle, rrTire radius of rear axle, JfMoment of inertia of the front axle, Jr-the moment of inertia of the rear axle,
Figure BDA0003169831240000155
-the acceleration of the front axle,
Figure BDA0003169831240000156
-acceleration of the rear axle.
If the vehicle is in a steady state such as a constant speed or acceleration, the acceleration of the front axle and the rear axle (also referred to as the front axle and the rear axle) is small, and the inertia force generated by the rotational inertia of the front axle and the rear axle is ignored, the following are provided:
Tr＝rrFxr
Tf＝rfFxf
thereby, the torque distribution coefficient lambda between the shafts1Can be expressed as:
Figure BDA0003169831240000157
when tan θ is equal to i and cos θ is equal to 1, the following are:
Figure BDA0003169831240000158
according to the above formula, passing the road gradient i and the vehicle acceleration axObtaining the torque distribution coefficient lambda between the shafts1And then the coaxial left and right motors are evenly distributed.
(S52) when the current operation mode of the electric vehicle is the economy operation mode, distributing the torque of each motor optimally according to the economy efficiency of the whole vehicle. Under the condition of ensuring that the required torque is met, the working loads of the motors on the front and rear shafts are adjusted, so that the working points of the motors on the front and rear shafts fall in a high-efficiency working area of the motors as far as possible, the working efficiency of the motors is improved, and the economical efficiency of a vehicle is ensured.
The real-time power calculation of the drive system is shown as follows:
Tr＝λ2·Ta
Tf＝(1-λ2)·Ta
Figure BDA0003169831240000161
Figure BDA0003169831240000162
Pall＝Pf+Pr
in the formula, TaIndicating driver demand torque, TfRepresenting front axle motor drive torque, TrRepresenting rear axle motor drive torque, λ2Represents the torque distribution coefficient between the shafts in the economy mode, n represents the motor rotation speed (assuming the four motors have the same rotation speed), ηf、ηrRespectively, the operating efficiencies of the front and rear shaft motors, Pf，PrRespectively representing the output power, P, of the front and rear axle motorsallRepresenting the total output power of the front and rear axle motors. The optimal control equation for the real-time power of the driving system is obtained according to the formula as follows:
Figure BDA0003169831240000163
while the distributed torque requirements of the front and rear axles are limited by the available capacity of the assembly:
λ2·Ta≤Tmaxr
(1-λ2)·Ta≤Tmaxf
in the formula, TmaxrRepresenting the total available torque, T, of the rear axle motormaxfRepresenting the total available torque of the front axle motor.
According to the current driver required torque and the reference speed of the vehicle and the working efficiency of the front and rear axle motors, a torque distribution table with the optimal real-time power of the driving system can be calculated off line, so that the power loss of the current driving system of the whole vehicle is minimized, and the optimal inter-axle torque distribution coefficients under different reference speeds and driving torque states of the front and rear axle motors are calculated.
It should be noted that, in some reference vehicle speed and motor driving torque states, there are situations where various torque distribution schemes minimize the power loss of the current driving system, and there are large fluctuations under low driving torque conditions, which are not favorable for control implementation. Therefore, in the optimizing process, the tolerance constraint condition is introduced, and the obtained optimal interaxial torque distribution coefficient is secondarily optimized.
The tolerance is defined as follows:
Figure BDA0003169831240000171
in the formula, Pall_bestRepresenting the total output power, P, corresponding to the optimal interaxial torque distribution coefficient at a certain operating pointall_TRepresenting the total output power with the tolerance constraint satisfied. I.e. total output power P of the motor on the front and rear axleall_bestTotal output power P with certain toleranceall_TI.e. the total output power P which is considered to be optimal for the torque distribution coefficient between the shaftsall_T. It can be understood that tolerance of 0 represents that the deviation of the total output power is 0, and the tolerance is set to be 0.5 in the embodiment, so as to obtain the torque distribution coefficient between the shafts meeting the precision requirement.
(S53) when the current working mode of the electric vehicle is the braking working modeThe torque distribution of the motor on the front axle and the motor on the rear axle needs to be optimally distributed with energy recovery efficiency, and the method is the same as the inter-axle torque distribution coefficient lambda under the economic working mode2Meanwhile, in order to ensure the braking safety, the torque distribution coefficient lambda between the shafts under the braking working moderearThe braking force is mainly distributed on the front axle, limited by the following formula:
λrear＝min(0.5,λ2)。
optionally, the distributed four-wheel-drive torque control method provided by the invention further comprises the step of judging whether the electric vehicle, namely the current vehicle, is in a steering working condition according to the opening degree of an accelerator pedal, the reference vehicle speed, the steering wheel angle and the steering wheel steering angular speed, and improving the steering stability of the vehicle through dynamic axle load transfer under the steering working condition.
Firstly, the following parameters need to be considered for judging the steering condition: and when the steering judgment conditions are met, entering a steering working condition to enable the steering to open a control logic.
The steering determination conditions are:
(1) the opening degree of an accelerator pedal is greater than a set value A;
(2) the reference vehicle speed is greater than a set value B;
(3) the steering wheel angle is greater than a set value C, or the steering wheel angle is greater than a set value D (D is less than C), and the steering wheel steering angular speed is greater than a set value E.
When the three conditions are simultaneously met, the vehicle is judged to enter a steering working condition, and under the steering working condition, the vehicle adopts a control method of forward movement of axle load, and the control method specifically comprises the following steps of:
when the steering working condition is met, the front axle reduces the torque and has the duration of t1, and then reduces the torque and recovers the torque and has the duration of t1-t 2; and reducing the torque of the front axle again for the duration of t2-t3, then reducing the torque for recovery for the duration of t3-t4, … …, and repeating the steps, wherein the driving torque of the front axle of the vehicle is reduced through a plurality of interval torque reduction recovery sections (the time sections of the front axle torque being 0), so that the axle load of the vehicle is moved forwards, and the purpose of improving the bending performance of the vehicle is achieved. Preferably, the time duration of 1 front axle torque has an equal time duration t1 and the time duration of 0 front axle torque has an equal time duration (t2-t 1). When the vehicle is in a steering state, the steering performance of the vehicle can be improved through active axle load transfer.
Optionally, the required torque of each motor is constrained by the stability control strategy and the active anti-skid control strategy to output the required torque of the motor.
1) When the vehicle has sideslip and tail flick, the driving torque of each motor is corrected according to a yaw control strategy, and the method specifically comprises the following steps: the method comprises the steps of obtaining a target yaw rate according to a reference vehicle speed and a steering wheel angle of a vehicle, correcting four motor driving torques on front and rear shafts of the vehicle according to the deviation of the target yaw rate and the obtained current actual yaw rate of the vehicle, and dynamically adjusting torque distribution of each wheel by a vehicle PID controller through closed-loop control according to the deviation of the yaw rate.
2) When the vehicle slips, the driving torque of each motor is corrected according to an active anti-slip strategy, and the method specifically comprises the following steps: acquiring a reference speed according to the wheel speed, the steering wheel angle and the yaw angular speed of the vehicle, and further calculating the slip rate of the vehicle; and correcting the motor driving torque on the vehicle according to the acceleration and the slip rate of the vehicle, and performing closed-loop control on wheel speed deviation through a vehicle PID controller when the slip rate exceeds a threshold value to prevent and limit the skidding of wheels.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. A distributed four-wheel-drive torque control method, comprising:
s1, acquiring the current parameters of the vehicle;
the current vehicle parameters comprise vehicle longitudinal acceleration, vehicle lateral acceleration, accelerator pedal opening, brake pedal opening, steering wheel angle, yaw rate, wheel speed and a current driver-selected vehicle operating mode;
s2, calculating a reference vehicle speed, a vehicle acceleration, a road adhesion coefficient, and a road gradient from the vehicle longitudinal acceleration, the vehicle lateral acceleration, the steering wheel angle, the yaw rate, and the wheel speed;
s3, calculating a driving stability factor according to the road adhesion coefficient, the vehicle acceleration, the reference vehicle speed and the steering wheel angle;
s4, selecting a vehicle working mode according to the accelerator pedal opening, the brake pedal opening, the reference vehicle speed, the steering wheel angle and the current vehicle operation mode;
the vehicle working modes are divided into three types, namely a movement working mode, an economic working mode and a braking working mode;
s5, when the vehicle is in any one of the motion working mode, the economy working mode and the brake working mode, four motor torques are calculated to realize distributed four-wheel drive torque control, and the specific calculation process is as follows:
(S51) when the current vehicle working mode of the electric vehicle is the movement working mode, performing dynamic analysis on the front and rear axle loads of the vehicle, considering the acceleration resistance and the gradient resistance of the vehicle, omitting the air resistance, the rolling resistance couple moment and the rotary inertia of the tire, and simplifying the axle load calculation of the front and rear axles into:
Figure FDA0003169831230000011
Figure FDA0003169831230000012
in the formula, Fzf，FzrVertical force of front and rear axles, m-vehicle mass, g-acceleration of gravity, hgHeight of vehicle center of mass, ax-vehicle longitudinal acceleration, θ -ramp angle, a-front axle to vehicle center of mass distance, b-rear axle to vehicle center of mass distance, L ═ a + b represents vehicle wheelbase;
the road surface utilization adhesion coefficients of the front axle and the rear axle are respectively as follows:
Figure FDA0003169831230000021
Figure FDA0003169831230000022
in the formula, mufAnd murUsing the coefficient of adhesion, F, for the road surface of the front axle and the rear axle, respectivelyxfLongitudinal tire force of front axle, FxrLongitudinal tire force for the rear axle;
the road surface utilization adhesion coefficient of the front axle and the rear axle is equal, and the road surface utilization adhesion coefficient comprises the following components:
Figure FDA0003169831230000023
assuming an interaxial torque distribution coefficient lambda in said kinematic operating mode1Comprises the following steps:
Figure FDA0003169831230000024
neglecting the rolling resistance couple moment of the wheel, the motor driving torque T of the front and rear axlesf、TrLongitudinal loads F with front and rear axlesxf、FxrThe relationship of (1) is:
Figure FDA0003169831230000025
Figure FDA0003169831230000026
in the formula, rfRadius of the tire of the front axle, rrRadius of the rear axle, JfMoment of inertia of the front axle, Jr-the moment of inertia of the rear axle,
Figure FDA0003169831230000027
-the acceleration of the front axle or axles,
Figure FDA0003169831230000028
-acceleration of the rear axle;
if the vehicle is in a constant speed or acceleration stable state, and inertia force generated by rotational inertia of a front shaft and a rear shaft is ignored, the following steps are provided:
Tr＝rrFxr
Tf＝rfFxf
thereby, the torque distribution coefficient lambda between the shafts1Expressed as:
Figure FDA0003169831230000031
when tan θ is equal to i and cos θ is equal to 1, there are,
Figure FDA0003169831230000032
according to the above formula, passing the road gradient i and the vehicle acceleration axObtaining the torque distribution coefficient lambda between the shafts1Then, the coaxial left and right motors are evenly distributed;
(S52) when the current vehicle operation mode of the electric vehicle is the economy operation mode, calculating the real-time power of the driving system according to the following formula:
Tr＝λ2·Ta
Tf＝(1-λ2)·Ta
Figure FDA0003169831230000033
Figure FDA0003169831230000034
Pall＝Pf+Pr
in the formula, TaIndicating driver demand torque, TfRepresenting front axle motor drive torque, TrRepresenting rear axle motor drive torque, λ2Representing the torque distribution coefficient between the shafts in the economy mode, n representing the motor speed, etaf、ηrRespectively, the operating efficiencies of the front and rear shaft motors, Pf，PrRespectively representing the output power, P, of the front and rear axle motorsallThe total output power of the front and rear shaft motors is represented, and the optimal control equation for obtaining the real-time power of the driving system according to the formula is as follows:
Figure FDA0003169831230000035
while the distributed torque requirements of the front and rear axles are limited by the available capacity of the assembly:
λ2·Ta≤Tmaxr
(1-λ2)·Ta≤Tmaxf
in the formula, TmaxrRepresenting the total available torque, T, of the rear axle motormaxfRepresenting the total available torque of the front axle motor;
according to the current driver required torque and the reference speed of the vehicle, the working efficiency of front and rear axle motors is combined, a torque distribution table with the optimal real-time power of a driving system is calculated in an off-line mode, so that the power loss of the current driving system of the whole vehicle is minimized, and the optimal inter-axle torque distribution coefficients in different reference speeds and driving torque states of the front and rear axle motors are calculated;
(S53) when the current vehicle operation mode of the electric vehicle is the brake operation mode, an inter-axle torque distribution coefficient λ in the brake operation moderearThe braking force distribution is realized on the front axle, limited by the following formula:
λrear＝min(0.5，λ2)。
2. the distributed four-wheel drive torque control method according to claim 1, wherein the vehicle operating modes include a comfort operating mode, an economy operating mode, and a sport operating mode.
3. The distributed four-wheel drive torque control method according to claim 1, wherein the reference vehicle speed is obtained by:
normalizing the wheel speed of each wheel at the center of a rear axle;
Figure FDA0003169831230000041
Figure FDA0003169831230000042
Figure FDA0003169831230000043
Figure FDA0003169831230000044
in the formula (I), the compound is shown in the specification,
vflfor the longitudinal speed of the left front wheel, vfrLongitudinal speed of the right front wheel, vrlIs the left rearWheel longitudinal speed, vrrIs the longitudinal speed of the right rear wheel, vfl_xLongitudinal speed, v, of the left front wheel at the center of the rear axlefr_xLongitudinal speed, v, of the right front wheel at the center of the rear axlerl_xLongitudinal speed, v, of the left rear wheel at the centre of the rear axlerr_xIs the longitudinal speed of the right rear wheel at the center of the rear axle, L is the vehicle wheelbase, b is the wheel moment, delta is the front wheel corner,
Figure FDA0003169831230000051
the yaw angular velocity;
the smallest normalized wheel speed is selected as the reference vehicle speed, i.e.:
vref_veh＝min(vfl_x，vfr_x，vrl_x,vrr_x)。
4. the distributed four-wheel drive torque control method according to claim 3, characterized in that the vehicle acceleration aact：
Figure FDA0003169831230000052
Wherein the content of the first and second substances,
Figure FDA0003169831230000053
for reference vehicle speed vref_vehThe derivative of (c).
5. The distributed four-wheel drive torque control method according to claim 4, wherein the road adhesion coefficient takes into account two conditions:
if the drive slip is triggered, the road adhesion coefficient is updated with the current vehicle acceleration:
μ＝aact
if the driving antiskid function is not triggered, the road adhesion coefficient is updated to be the maximum value of the current vehicle acceleration and the road adhesion coefficient at the last moment:
μ＝max(aact，μ)
in the formula, vref_vehFor reference vehicle speed, μ is road adhesion coefficient, aactIs the vehicle acceleration.
6. The distributed four-wheel drive torque control method according to claim 1, wherein the road grade i is:
Figure FDA0003169831230000054
wherein i represents a road gradient; a isxRepresenting the longitudinal acceleration measured by the sensor, g representing the gravitational acceleration, vxIndicating the longitudinal speed of the vehicle.
7. The distributed four-wheel drive torque control method according to claim 4, wherein the running stability factor γ is as follows:
Figure FDA0003169831230000061
wherein gamma is a driving stability factor, fac1 and fac2 are factors related to a reference vehicle speed and a steering wheel angle respectively, and the values of the factors are between 0 and 1.
8. The distributed four-wheel drive torque control method according to claim 2, wherein the vehicle operating modes are divided by:
(1) the vehicle enters the sport mode of operation in any one of the following situations:
(1.1) the opening degree of an accelerator pedal is greater than a first preset opening degree;
(1.2) the opening degree of the accelerator pedal is greater than a second preset opening degree and smaller than a first preset opening degree, the change rate of the opening degree of the accelerator pedal is greater than a first preset value, and the received mode command is a comfortable operation mode command;
(1.3) the driving stability factor is greater than a set value and the received mode command is the comfort operation mode command;
(1.4) the road adhesion coefficient is smaller than a set value, and the received mode command is the comfort operation mode command;
(1.5) the road grade is greater than a set value and the received mode command is the comfort operation mode command;
(1.6) the received mode command is the sport operating mode command;
(2) entering the economy mode of operation in any one of:
(2.1) the opening degree of the accelerator pedal is greater than 0 and less than or equal to a second preset opening degree, and the received mode command is the comfortable operation mode command;
(2.2) the received mode command is the economy operation mode command;
(3) entering the braking mode of operation in any one of:
(3.1) the accelerator pedal opening is 0 and the received mode command is the comfort operation mode command;
and (3.2) the brake pedal opening degree signal is greater than 0.
9. The distributed four-wheel drive torque control method according to claim 1, wherein the step S52 further includes a step of performing a second optimization on the optimal inter-axle torque distribution coefficient, specifically:
the tolerance is defined as follows:
Figure FDA0003169831230000071
in the formula, Pall_bestRepresenting the total output power, P, corresponding to the optimal interaxial torque distribution coefficient at a certain operating pointall_TRepresenting the total output power with the tolerance constraint satisfied.
10. The distributed four-wheel drive torque control method according to claim 1, further comprising torque distribution control of a steering condition, wherein the judgment condition of the steering condition is as follows:
(1) the opening degree of the accelerator pedal is greater than a set value A;
(2) the reference vehicle speed is greater than a set value B;
(3) the steering wheel angle is greater than a set value C; or the steering wheel rotating angle is larger than a set value D, and the steering wheel steering angular speed is larger than a set value E, wherein the set value D is smaller than the set value C;
when the three conditions are met simultaneously, the vehicle enters a steering working condition, and the control method of the forward movement of the axle load is adopted by the vehicle, and specifically comprises the following steps:
when the steering working condition is met, the front axle reduces the torque and has the duration of t1, and then reduces the torque and recovers the torque and has the duration of t1-t 2; the front axle torque is again reduced for a duration of t2-t3, then the torque reduction is resumed for a duration of t3-t4, … …, and so on, by a plurality of spaced front axle torque reductions, the vehicle axle load is advanced.
CN202110814949.5A 2021-07-19 2021-07-19 Distributed four-wheel drive torque control method Active CN113335263B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202110814949.5A CN113335263B (en) 2021-07-19 2021-07-19 Distributed four-wheel drive torque control method
PCT/CN2022/106240 WO2023001100A1 (en) 2021-07-19 2022-07-18 Distributed four-wheel drive torque control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110814949.5A CN113335263B (en) 2021-07-19 2021-07-19 Distributed four-wheel drive torque control method

Publications (2)

Publication Number Publication Date
CN113335263A CN113335263A (en) 2021-09-03
CN113335263B true CN113335263B (en) 2022-04-12

Family

ID=77479990

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110814949.5A Active CN113335263B (en) 2021-07-19 2021-07-19 Distributed four-wheel drive torque control method

Country Status (2)

Country Link
CN (1) CN113335263B (en)
WO (1) WO2023001100A1 (en)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113815618B (en) * 2021-10-26 2023-03-28 中国第一汽车股份有限公司 Control method for keeping vehicle driving
CN114212091B (en) * 2021-12-30 2023-05-23 重庆长安新能源汽车科技有限公司 Control method for power transmission device of electric automobile, vehicle and computer readable storage medium
CN114228496A (en) * 2021-12-31 2022-03-25 优跑汽车技术(上海)有限公司 Drive control method and device, vehicle chassis and electric vehicle
CN114435377B (en) * 2022-02-25 2024-05-24 广汽埃安新能源汽车有限公司 Method and device for acquiring reference vehicle speed, electronic equipment and storage medium
CN114954034A (en) * 2022-05-25 2022-08-30 中国第一汽车股份有限公司 Vehicle torque distribution method and device and vehicle
CN115139815B (en) * 2022-06-27 2024-04-09 重庆金康赛力斯新能源汽车设计院有限公司 Torque distribution method, device, equipment and storage medium
CN117622130A (en) * 2022-08-10 2024-03-01 罗伯特·博世有限公司 Anti-slip control method and equipment for torque between electric drive axle shafts of multi-axle vehicle
CN115384469B (en) * 2022-08-24 2024-01-09 西安主函数智能科技有限公司 Dynamic torque distribution method based on air brake and electric brake of new energy engineering vehicle
CN116278803B (en) * 2023-03-30 2024-03-08 吉林大学 Energy-saving torque distribution system of electric automobile driven by four-wheel hub motor and control method thereof
CN116638950A (en) * 2023-06-15 2023-08-25 中国第一汽车股份有限公司 Four-drive force system, vehicle, and control method for vehicle
CN117183750A (en) * 2023-11-01 2023-12-08 小米汽车科技有限公司 Torque control method in vehicle energy recovery and related products
CN117485325B (en) * 2024-01-02 2024-03-19 中国重汽集团济南动力有限公司 Multi-axis distributed electric drive vehicle steering control method and vehicle

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011021634A1 (en) * 2009-08-18 2011-02-24 トヨタ自動車株式会社 Vehicle control device
WO2011021084A2 (en) * 2009-08-18 2011-02-24 Toyota Jidosha Kabushiki Kaisha Vehicle control system
WO2012043683A1 (en) * 2010-09-28 2012-04-05 日立オートモティブシステムズ株式会社 Vehicle motion control device
JP4965751B1 (en) * 2011-04-21 2012-07-04 パイオニア株式会社 Torque distribution device, torque distribution method, torque distribution value generation method, and program
CN108357494A (en) * 2018-02-11 2018-08-03 重庆长安汽车股份有限公司 A kind of automatically controlled in due course 4 wheel driven control method
CN110014851A (en) * 2019-04-10 2019-07-16 中国第一汽车股份有限公司 A kind of front and back bi-motor four-wheel drive cars between centers torque distribution method
CN110606075A (en) * 2019-08-28 2019-12-24 中国第一汽车股份有限公司 Torque distribution control method and system of distributed four-wheel-drive electric vehicle and vehicle
CN111845710A (en) * 2020-08-03 2020-10-30 北京理工大学 Method and system for controlling dynamic performance of whole vehicle based on pavement adhesion coefficient identification
CN111845775A (en) * 2020-07-20 2020-10-30 上海大学 Joint estimation method for driving state and inertia parameters of distributed driving electric automobile
CN112026536A (en) * 2020-09-07 2020-12-04 中国第一汽车股份有限公司 Driving anti-skid control method of electric automobile and double-motor four-wheel-drive electric automobile
CN112026775A (en) * 2020-09-09 2020-12-04 东风汽车有限公司 Vehicle four-wheel drive control method and electronic equipment
CN113071332A (en) * 2021-04-28 2021-07-06 中国第一汽车股份有限公司 Torque control method for dual-motor electric vehicle, electric vehicle and storage medium

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011021634A1 (en) * 2009-08-18 2011-02-24 トヨタ自動車株式会社 Vehicle control device
WO2011021084A2 (en) * 2009-08-18 2011-02-24 Toyota Jidosha Kabushiki Kaisha Vehicle control system
WO2012043683A1 (en) * 2010-09-28 2012-04-05 日立オートモティブシステムズ株式会社 Vehicle motion control device
JP4965751B1 (en) * 2011-04-21 2012-07-04 パイオニア株式会社 Torque distribution device, torque distribution method, torque distribution value generation method, and program
CN108357494A (en) * 2018-02-11 2018-08-03 重庆长安汽车股份有限公司 A kind of automatically controlled in due course 4 wheel driven control method
CN110014851A (en) * 2019-04-10 2019-07-16 中国第一汽车股份有限公司 A kind of front and back bi-motor four-wheel drive cars between centers torque distribution method
CN110606075A (en) * 2019-08-28 2019-12-24 中国第一汽车股份有限公司 Torque distribution control method and system of distributed four-wheel-drive electric vehicle and vehicle
CN111845775A (en) * 2020-07-20 2020-10-30 上海大学 Joint estimation method for driving state and inertia parameters of distributed driving electric automobile
CN111845710A (en) * 2020-08-03 2020-10-30 北京理工大学 Method and system for controlling dynamic performance of whole vehicle based on pavement adhesion coefficient identification
CN112026536A (en) * 2020-09-07 2020-12-04 中国第一汽车股份有限公司 Driving anti-skid control method of electric automobile and double-motor four-wheel-drive electric automobile
CN112026775A (en) * 2020-09-09 2020-12-04 东风汽车有限公司 Vehicle four-wheel drive control method and electronic equipment
CN113071332A (en) * 2021-04-28 2021-07-06 中国第一汽车股份有限公司 Torque control method for dual-motor electric vehicle, electric vehicle and storage medium

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
特种车辆多轮分布式电驱动系统设计研究;邹波等;《车辆与动力技术》;20171215(第04期);全文 *

Also Published As

Publication number Publication date
WO2023001100A1 (en) 2023-01-26
CN113335263A (en) 2021-09-03

Similar Documents

Publication Publication Date Title
CN113335263B (en) Distributed four-wheel drive torque control method
CN104786804B (en) A kind of vehicle and its Direct wheel drives system and Direct wheel drives moment of torsion distribution method
CN104175902B (en) The torque distribution control method of electric wheel truck wheel hub motor torque-split system
CN107472082B (en) driving torque distribution method and system of four-wheel drive electric automobile and electric automobile
CN108237950B (en) Vehicle control method and system and vehicle
EP1698507B1 (en) Vehicle regenerative braking control apparatus and method
CN106183892B (en) The experimental model and driving stability control method of electric wheel drive vehicle
CN104210383B (en) A kind of four-wheel drive electric automobile torque distribution control method and system
CN110254405B (en) Automobile brake-by-wire control system for automatic driving and intelligent auxiliary driving and control method thereof
CN109747632B (en) Torque distribution method for double-power-source driven vehicle
CN108944910B (en) Vehicle steady state intelligent control method and device
CN108790940A (en) Direct wheel drives turn to differential speed control method, control device, equipment and automobile
CN107953801A (en) A kind of driving force control method of full wheel-hub motor driven vehicle
CN109606133A (en) Distributed-driving electric automobile torque vector control method based on bilayer control
CN108725214A (en) Four wheel hub motor-driven vehicles of composite braking brake anti-skid control method
CN105691381A (en) Stability control method and system for electric automobile with four independently driven wheels
JP2010273540A (en) Independent braking and controllability control method, and system for vehicle with regenerative braking
JP2004099029A (en) Braking and controllability control method and system of vehicle with regenerative braking
CN111469670A (en) Electric automobile regenerative braking control strategy based on road surface identification
CN106080605B (en) A kind of wheel torque distribution method based on forerunner's hub motor
CN107139924B (en) A kind of electronic limited slip differential device and its control method
CN108297736A (en) A kind of bi-motor distributed-driving electric automobile and motor control strategy
CN101108615A (en) Driving dynamics control system having an expanded braking function
CN113002324B (en) Electronic differential system of four-wheel independent driving and independent steering electric automobile
CN112172788A (en) Distributed three-motor driving force distribution strategy for improving vehicle steering stability

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant