CN114312752B - Steering vehicle speed control method for electric vehicle - Google Patents

Steering vehicle speed control method for electric vehicle Download PDF

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CN114312752B
CN114312752B CN202210073426.4A CN202210073426A CN114312752B CN 114312752 B CN114312752 B CN 114312752B CN 202210073426 A CN202210073426 A CN 202210073426A CN 114312752 B CN114312752 B CN 114312752B
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vehicle
vehicle speed
steering
stability
control method
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CN114312752A (en
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吴焜昌
黄玲
刘志伟
卢涛
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Xiamen King Long United Automotive Industry Co Ltd
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Xiamen King Long United Automotive Industry Co Ltd
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    • 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
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    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

Abstract

The invention relates to a steering vehicle speed control method of an electric vehicle, which comprises the following steps of: i, calculating an ideal yaw rate limited by road surface conditions according to a two-degree-of-freedom vehicle model; II, defining a reference yaw rate; III, determining the upper limit vehicle speed of stability when the vehicle turns according to the reference yaw rate; IV, from the upper limit vehicle speed of the stability
Figure DEST_PATH_IMAGE002
The generalized longitudinal force of the final output is determined. The invention passes the upper limit speed of the vehicle during the steering of the vehicle
Figure 648174DEST_PATH_IMAGE002
When the vehicle speed is lower than the stability upper limit vehicle speed, the final output generalized longitudinal force reflects the acceleration requirement of a driver and is obtained by combining an accelerator pedal with external characteristic analysis of a motor; when the vehicle speed is higher than the upper limit of the stability, the braking force is introduced
Figure DEST_PATH_IMAGE004
The final output generalized longitudinal force is reduced, so that the total required torque of the whole vehicle is reduced, and then the vehicle is stably driven by torque coordination control between the left driving wheel and the right driving wheel of the distributed driving vehicle, so that the vehicle speed is reduced, and the yaw moment is adjusted.

Description

Steering vehicle speed control method for electric vehicle
Technical Field
The invention relates to the field of control of distributed driving electric automobiles, in particular to a steering speed control method of an electric automobile.
Background
The distributed driving electric automobile is an emerging driving type automobile, and has high transmission efficiency, good economy, good dynamics controllability and the like, so that the distributed driving electric automobile becomes an important direction of automobile development. The distributed driving electric automobile calculates ideal yaw rate according to the vehicle model, and can improve the linear response of the vehicle steering by being used as a motion tracking reference value under the conventional working condition of the vehicle, so that the advantages of the distributed driving vehicle are fully exerted. However, as the lateral acceleration of the vehicle increases during cornering, the cornering stiffness of the front and rear axles of the vehicle gradually decreases, which results in a larger tire cornering angle, thereby reducing the stability of the vehicle. With the increase of the lateral acceleration, the reference yaw rate of the vehicle needs to be weakened, and the stability requirement of the vehicle is ensured. The existing electric automobile steering speed control method lacks consideration of steering stability of the vehicle in the direction, and has the problems that the vehicle stability requirement and the driver acceleration requirement cannot be unified well in the vehicle steering, namely, the problem that the vehicle steering stability is sacrificed or the vehicle stability is guaranteed and the longitudinal force finally output by the vehicle is reduced too early due to the fact that the driver acceleration requirement is guaranteed.
Disclosure of Invention
The invention provides a steering vehicle speed control method of an electric vehicle, which aims to solve the problems.
The invention adopts the following technical scheme:
the electric automobile steering speed control method comprises the following steps:
calculating an ideal yaw rate limited by road surface conditions according to the two-degree-of-freedom vehicle model
Figure DEST_PATH_IMAGE001
。
II, defining a reference yaw rate
Figure 170713DEST_PATH_IMAGE002
。
Figure DEST_PATH_IMAGE003
。
wherein ,
Figure 580966DEST_PATH_IMAGE004
is a stability control index. />
Figure DEST_PATH_IMAGE005
For stability yaw rate limit.
Figure 366519DEST_PATH_IMAGE006
。
Figure DEST_PATH_IMAGE007
。
III. From the above-mentioned reference yaw rate
Figure 727968DEST_PATH_IMAGE002
Determining the upper limit vehicle speed of stability when the vehicle turns to +.>
Figure 421118DEST_PATH_IMAGE008
。
Figure DEST_PATH_IMAGE009
。
wherein ,
Figure 685877DEST_PATH_IMAGE010
is the vehicle maximum lateral acceleration reference.
IV, from the upper limit vehicle speed of the stability
Figure 439069DEST_PATH_IMAGE008
Determining the generalized longitudinal force of the final output +.>
Figure 117175DEST_PATH_IMAGE011
。/>
Figure 898836DEST_PATH_IMAGE012
。
wherein ,
Figure DEST_PATH_IMAGE013
the driving force is analyzed for the accelerator pedal.
Figure 283681DEST_PATH_IMAGE014
。
Further:
the ideal yaw rate
Figure 411037DEST_PATH_IMAGE001
The method comprises the following steps:
Figure 278237DEST_PATH_IMAGE015
。
wherein ,
Figure DEST_PATH_IMAGE016
is the reference lateral acceleration. />
Figure 782031DEST_PATH_IMAGE017
Is the longitudinal vehicle speed. />
Figure DEST_PATH_IMAGE018
Is the road adhesion coefficient. g is gravitational acceleration. />
Figure 755803DEST_PATH_IMAGE019
And the experimental coefficient is the experimental coefficient calibrated through testing according to actual conditions.
The electric car steering speed control method is used for distributed driving.
In the above step III
Figure DEST_PATH_IMAGE020
。
Above-mentioned
Figure 585219DEST_PATH_IMAGE019
=0.85。
The electric automobile steering speed control method is that the electric automobile steering speed is based on a domain controllerTo a vehicle speed control method. The domain controller comprises a domain control main station and a domain control auxiliary station, wherein the domain control auxiliary station acquires signals of the current speed, the lateral acceleration, the steering wheel rotation angle and the like of a vehicle, and transmits the signals to the domain control main station through CAN communication after processing, and the domain control main station calculates the final output generalized longitudinal force
Figure 441179DEST_PATH_IMAGE011
And transmitted to the domain control slave station for execution through CAN communication.
The hardware architecture of the domain controller is divided into two CPUs, the two CPUs are communicated internally by adopting a high-speed serial port, one CPU is responsible for high-voltage control and energy management of the whole vehicle, and the other CPU is responsible for torque distribution control of a distributed motor and calculation of the final output generalized longitudinal force
Figure 527426DEST_PATH_IMAGE021
。
From the above description of the invention, it is clear that the invention has the following advantages over the prior art:
the invention passes the upper limit speed of the vehicle during the steering of the vehicle
Figure DEST_PATH_IMAGE022
When the vehicle speed is lower than the stability upper limit vehicle speed, the final output generalized longitudinal force reflects the acceleration requirement of a driver and is obtained by combining an accelerator pedal with external characteristic analysis of a motor; and when the vehicle speed is higher than the upper limit vehicle speed for stability, the braking force is introduced +.>
Figure 355705DEST_PATH_IMAGE023
The final output generalized longitudinal force is reduced, so that the total required torque of the whole vehicle is reduced, and then the vehicle is stably driven by torque coordination control between the left driving wheel and the right driving wheel of the distributed driving vehicle, so that the vehicle speed is reduced, and the yaw moment is adjusted. Namely, the invention well unifies the vehicle stability requirement and the driver acceleration requirement, and on the premise of ensuring the steering stability of the vehicle, the vehicle can be enabled to have a vehicle speed higher than the stability upper limit vehicle speed +.>
Figure 559285DEST_PATH_IMAGE008
The generalized longitudinal force finally output is reduced, and the acceleration requirement of a driver is guaranteed to the maximum extent.
Drawings
Fig. 1 is a flowchart of a steering vehicle speed control method of an electric vehicle according to the present invention.
Detailed Description
Specific embodiments of the present invention will be described below with reference to the accompanying drawings.
Referring to fig. 1, a steering speed control method of an electric car, in particular to a steering speed control method of a distributed driving electric bus based on a domain controller. The domain controller comprises a domain control master station and a domain control slave station, wherein the domain control slave station acquires signals of the current speed, the lateral acceleration, the steering wheel rotation angle and the like of a vehicle, and transmits the signals to the domain control master station through CAN communication after processing, and the domain control master station calculates and obtains the final output generalized longitudinal force
Figure 636962DEST_PATH_IMAGE011
And transmitted to the domain control slave station for execution through CAN communication. The hardware architecture of the domain controller is divided into two CPUs, the two CPUs are communicated internally by adopting a high-speed serial port, one CPU is responsible for high-voltage control and energy management of the whole vehicle, and the other CPU is responsible for torque distribution control of a distributed motor and generalized longitudinal force (I) of calculating the final output is calculated>
Figure 544875DEST_PATH_IMAGE011
。
With continued reference to fig. 1, the electric vehicle steering vehicle speed control method includes the following steps:
calculating an ideal yaw rate limited by road surface conditions according to the two-degree-of-freedom vehicle model
Figure 522933DEST_PATH_IMAGE024
。
Figure 631835DEST_PATH_IMAGE015
。
wherein ,
Figure 196808DEST_PATH_IMAGE016
is the reference lateral acceleration. />
Figure 908412DEST_PATH_IMAGE017
Is the longitudinal vehicle speed. />
Figure 508021DEST_PATH_IMAGE018
Is the road adhesion coefficient. g is gravitational acceleration. />
Figure 115720DEST_PATH_IMAGE019
And the experimental coefficient is the experimental coefficient calibrated through testing according to actual conditions. />
Figure 167989DEST_PATH_IMAGE019
=0.85。
II, defining a reference yaw rate
Figure 591274DEST_PATH_IMAGE025
。
Figure 45389DEST_PATH_IMAGE003
。
wherein ,
Figure 823989DEST_PATH_IMAGE004
is a stability control index. />
Figure 363555DEST_PATH_IMAGE005
For stability yaw rate limit.
Figure 885803DEST_PATH_IMAGE006
。
Stability control index
Figure 194425DEST_PATH_IMAGE004
The introduction of the method enables the steering speed control method of the electric automobile to simultaneously consider the steering operability and the steering stability of the automobile. Wherein->
Figure 409505DEST_PATH_IMAGE026
Is the vehicle lateral acceleration.
Figure 403744DEST_PATH_IMAGE007
。
Manipulability reference value-ideal yaw rate obtained with two-degree-of-freedom vehicle model under normal operating conditions
Figure DEST_PATH_IMAGE027
(i.e., mainly improved handling); while when the lateral acceleration is gradually increased, the yaw rate is ideal
Figure 464104DEST_PATH_IMAGE027
The duty cycle gradually decreases, stability reference value-stability yaw rate limit +.>
Figure 830494DEST_PATH_IMAGE005
The duty cycle is gradually increased to achieve a continuous change in the final target value between the manipulability reference and the stability reference, thereby achieving coordination of the two.
While the stability yaw coefficient is
Figure 950897DEST_PATH_IMAGE028
The introduction of the method can play a role in inhibiting the divergence of the centroid side deflection angle when the centroid side deflection angle of the vehicle is larger, further reduce the yaw rate of the vehicle and ensure the stability of the vehicle.
III. From the above-mentioned reference yaw rate
Figure 261792DEST_PATH_IMAGE025
Determining the upper limit vehicle speed of stability when the vehicle turns to +.>
Figure 329106DEST_PATH_IMAGE008
。
Figure 143478DEST_PATH_IMAGE009
。
wherein ,
Figure 405088DEST_PATH_IMAGE010
is the vehicle maximum lateral acceleration reference. />
Figure 140963DEST_PATH_IMAGE020
。
Namely, since the lateral acceleration of the vehicle is constrained by the road surface adhesion limit, the vehicle is steered at the upper limit of the vehicle speed
Figure 543126DEST_PATH_IMAGE022
And calculating according to the maximum lateral acceleration reference value and the reference yaw rate of the vehicle. />
IV, from the upper limit vehicle speed of the stability
Figure 680846DEST_PATH_IMAGE022
Determining the generalized longitudinal force of the final output +.>
Figure 408630DEST_PATH_IMAGE021
。
Figure DEST_PATH_IMAGE029
。
wherein ,
Figure 835064DEST_PATH_IMAGE013
the driving force is analyzed for the accelerator pedal.
Figure 805032DEST_PATH_IMAGE014
。
Figure 797258DEST_PATH_IMAGE030
and />
Figure DEST_PATH_IMAGE031
P and I coefficients for PID control. Generalized longitudinal force of final output +.>
Figure 102469DEST_PATH_IMAGE011
Driving force generated by analysis of an accelerator pedal representing driver's intention and longitudinal control force calculated by the above method by means of the above domain controller +.>
Figure 812936DEST_PATH_IMAGE023
And the components are combined together. When the vehicle speed is lower than the upper limit vehicle speed of stability when the vehicle turns, the final output generalized longitudinal force reflects the acceleration requirement of a driver and is obtained by combining an accelerator pedal with external characteristics of a motor; when the vehicle speed is higher than the upper limit vehicle speed of stability at the time of vehicle steering, longitudinal control force calculated by means of the domain controller via the above method is introduced +.>
Figure 822480DEST_PATH_IMAGE023
As braking force, the generalized longitudinal force finally output is reduced, so that the total required torque of the whole vehicle is reduced, and the vehicle is kept stably running by reducing the vehicle speed and adjusting the yaw moment through the torque coordination control between the left driving wheel and the right driving wheel of the distributed driving vehicle. Meanwhile, compared with the existing distributed driving electric automobile, the mode that each part is provided with a separate controller to realize the function control of each part is adopted, the domain controller reduces the complexity of the whole control system, reduces the load rate of CAN communication and also reduces the hardware cost; at the same time, even with the addition of new functionality, the domain controller may be significantly advantageous due to the compact nature of the system.
The foregoing is merely illustrative of specific embodiments of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modification of the present invention by using the design concept shall fall within the scope of the present invention.

Claims (7)

1. The method for controlling the steering speed of the electric automobile is characterized by comprising the following steps of: the method comprises the following steps:
calculating an ideal yaw rate limited by road surface conditions according to the two-degree-of-freedom vehicle model
Figure QLYQS_1
；
II, defining a reference yaw rate
Figure QLYQS_2
；
Figure QLYQS_3
；
wherein ,
Figure QLYQS_4
is a stability control index; />
Figure QLYQS_5
Yaw rate limit for stability;
Figure QLYQS_6
；
wherein ,
Figure QLYQS_7
for vehicle lateral acceleration>
Figure QLYQS_8
G is the road adhesion coefficient and g is the gravitational acceleration;
Figure QLYQS_9
；
wherein ,
Figure QLYQS_10
for stabilizing yaw coefficient, i.e.)>
Figure QLYQS_11
Is the longitudinal vehicle speed;
III. From the reference yaw rate
Figure QLYQS_12
Determining the upper limit vehicle speed of stability when the vehicle turns to +.>
Figure QLYQS_13
；
Figure QLYQS_14
；
wherein ,
Figure QLYQS_15
a reference value for maximum lateral acceleration of the vehicle;
IV, driving by the upper limit vehicle speed of the stability
Figure QLYQS_16
Determining the generalized longitudinal force of the final output +.>
Figure QLYQS_17
；
Figure QLYQS_18
；
wherein ,
Figure QLYQS_19
a driving force analyzed for an accelerator pedal;
Figure QLYQS_20
；
wherein ,
Figure QLYQS_21
and />
Figure QLYQS_22
P and I coefficients for PID control.
2. The electric vehicle steering vehicle speed control method according to claim 1, characterized in that: the ideal yaw rate
Figure QLYQS_23
The method comprises the following steps:
Figure QLYQS_24
；
wherein ,
Figure QLYQS_25
is the reference lateral acceleration; />
Figure QLYQS_26
Is the longitudinal vehicle speed; />
Figure QLYQS_27
Is the road adhesion coefficient; g is gravity acceleration; />
Figure QLYQS_28
And the experimental coefficient is the experimental coefficient calibrated through testing according to actual conditions.
3. The electric vehicle steering vehicle speed control method according to claim 2, characterized in that: the electric car steering speed control method is used for distributed driving.
4. The electric vehicle steering vehicle speed control method according to claim 3, characterized in that: in the step III
Figure QLYQS_29
。
5. The electric vehicle steering vehicle speed control method according to claim 4, characterized in that: the said
Figure QLYQS_30
=0.85。
6. The electric vehicle steering vehicle speed control method according to any one of claims 3 to 5, characterized in that: the electric automobile steering speed control method is based on a domain controller; the domain controller comprises a domain control master station and a domain control slave station, the domain control slave station acquires signals of the current speed, the lateral acceleration, the steering wheel rotation angle and the like of the vehicle, the signals are transmitted to the domain control master station through CAN communication after being processed, and the domain control master station calculates and obtains the final output generalized longitudinal force
Figure QLYQS_31
And transmitted to the domain control slave station for execution through CAN communication.
7. The electric vehicle steering vehicle speed control method according to claim 6, characterized in that: the hardware architecture of the domain controller is divided into two CPUs, the two CPUs are communicated internally by adopting a high-speed serial port, one CPU is responsible for high-voltage control and energy management of the whole vehicle, and the other CPU is responsible for torque distribution control of a distributed motor and calculation of the final output generalized longitudinal force
Figure QLYQS_32
。/>
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KR20070102787A (en) * 2006-04-17 2007-10-22 주식회사 만도 Vehicle stability control system and method for the same
JP2009226991A (en) * 2008-03-19 2009-10-08 Toyota Motor Corp Controller for vehicle
JP2010081720A (en) * 2008-09-25 2010-04-08 Mazda Motor Corp Vehicular driving force controller
CN103786602A (en) * 2014-01-14 2014-05-14 同济大学 Maneuverability improving and controlling method based on distributively driven electric vehicle
CN108163044A (en) * 2017-12-11 2018-06-15 同济大学 The steering redundancy of four motorized wheels electric vehicle and integrated control system and method
CN109747434A (en) * 2019-01-16 2019-05-14 浙江科技学院 Distributed-driving electric automobile torque vector distributes control method
CN110395120A (en) * 2019-08-14 2019-11-01 厦门金龙联合汽车工业有限公司 A kind of weaving control method of four-wheel distribution driving car
CN112644457A (en) * 2021-01-08 2021-04-13 江苏大学 Distributed driving vehicle steering stability control system and control method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100684033B1 (en) * 2002-02-23 2007-02-16 주식회사 만도 Method for controlling the stability of vehicles

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20070102787A (en) * 2006-04-17 2007-10-22 주식회사 만도 Vehicle stability control system and method for the same
JP2009226991A (en) * 2008-03-19 2009-10-08 Toyota Motor Corp Controller for vehicle
JP2010081720A (en) * 2008-09-25 2010-04-08 Mazda Motor Corp Vehicular driving force controller
CN103786602A (en) * 2014-01-14 2014-05-14 同济大学 Maneuverability improving and controlling method based on distributively driven electric vehicle
CN108163044A (en) * 2017-12-11 2018-06-15 同济大学 The steering redundancy of four motorized wheels electric vehicle and integrated control system and method
CN109747434A (en) * 2019-01-16 2019-05-14 浙江科技学院 Distributed-driving electric automobile torque vector distributes control method
CN110395120A (en) * 2019-08-14 2019-11-01 厦门金龙联合汽车工业有限公司 A kind of weaving control method of four-wheel distribution driving car
CN112644457A (en) * 2021-01-08 2021-04-13 江苏大学 Distributed driving vehicle steering stability control system and control method thereof

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