CN111497932A - Novel electric automobile capable of reducing steering radius, control system and control method - Google Patents

Novel electric automobile capable of reducing steering radius, control system and control method Download PDF

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Publication number
CN111497932A
CN111497932A CN202010358825.6A CN202010358825A CN111497932A CN 111497932 A CN111497932 A CN 111497932A CN 202010358825 A CN202010358825 A CN 202010358825A CN 111497932 A CN111497932 A CN 111497932A
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China
Prior art keywords
steering
wheel
automobile
radius
wheels
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CN202010358825.6A
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Chinese (zh)
Inventor
孟令韩
孙彩凤
索明何
刘琼琼
张秋霞
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Huaian Vocational College of Information Technology
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Huaian Vocational College of Information Technology
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Priority to CN202010358825.6A priority Critical patent/CN111497932A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/046—Controlling the motor
    • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
    • B62D11/001—Steering non-deflectable wheels; Steering endless tracks or the like control systems
    • B62D11/003—Electric or electronic control systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
    • B62D11/02—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides
    • B62D11/04—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of separate power sources
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/001—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits the torque NOT being among the input parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2220/00—Electrical machine types; Structures or applications thereof
    • B60L2220/40—Electrical machine applications
    • B60L2220/42—Electrical machine applications with use of more than one motor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2220/00—Electrical machine types; Structures or applications thereof
    • B60L2220/40—Electrical machine applications
    • B60L2220/44—Wheel Hub motors, i.e. integrated in the wheel hub
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B60L2240/24—Steering angle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • 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

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Automation & Control Theory (AREA)
  • Power Engineering (AREA)
  • Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)

Abstract

The invention belongs to the technical field of electric automobile control, and discloses a novel electric automobile capable of reducing steering radius, a control system and a control method, wherein the novel electric automobile capable of reducing steering radius comprises the following steps: detecting the steering angle of the steering wheel through a steering wheel rotation angle sensor; detecting the rolling speed of the driving wheel through a driving wheel rolling angle sensor; signals of all the sensors are received through a steering control computer, calculation and analysis are carried out, then judgment is made, corresponding rotating speed instructions are sent to the two steering motors and the hub motor, and finally the small-radius steering of the automobile according with the Ackerman steering geometric characteristics is achieved. The novel electric automobile capable of reducing the steering radius is provided with two steering motors which respectively and independently control the rotation angles of the steering wheels on the same side, and through accurate control of a computer, the Ackerman steering geometric relationship can be more easily achieved, and switching of the automobile among different steering modes is realized.

Description

Novel electric automobile capable of reducing steering radius, control system and control method
Technical Field
The invention belongs to the technical field of electric automobile steering control, and particularly relates to a novel electric automobile capable of reducing steering radius, a control system and a control method.
Background
At present, four-wheel automobiles in the market mostly adopt two-wheel steering, the steering wheels drive the automobiles to steer in the turning process, only two wheels can steer, and the other two wheels have no steering function, so that the automobile finally performs circular motion along a larger virtual circular track. The turning radius of such two-wheeled vehicles tends to be larger than the vehicle size: the minimum turning radius of a household automobile is generally 4 to 8 meters, and the turning radius of a large automobile can even reach 10 to 20 meters. When the vehicle meets a road condition with a small operation space, such as a parking lot or a narrow road surface, the defect of poor maneuverability of the vehicle is often revealed due to the overlarge steering radius, and a driver needs to perform multiple operations of backing and advancing to achieve the purpose of changing the direction of the vehicle. This process is often time consuming and labor intensive, and may even affect the performance of important tasks for some special vehicles, such as fire trucks.
Meanwhile, there are very few four-wheel steering cars on the market, i.e. four vehicles all participate in steering. Because the number of the steering wheels is more, the steering radius of the automobile can be greatly reduced, and even some automobiles can realize pivot steering. The maneuverability of the automobile during steering is greatly improved, and the automobile can easily enter and exit even under the condition of congested road conditions or narrow roads. The disadvantage of this kind of automobile is that the structural design is very complicated, and the application range is very limited and the reliability is not high because many defects in the structural design are not completely solved. Therefore, four-wheel vehicles in the modern automotive market are mainly based on two-wheel steering.
Electric automobiles on the market at present are all chassis of traditional fuel automobiles, including steering systems. Because of the cost problem and the technical problem, the two-wheel steering is mainly used at present, so the defect of overlarge steering radius of the traditional automobile is inherited. This eventually causes inconvenience to drivers and road traffic and even social security. Therefore, it is highly desirable to design a device to reduce the steering radius of a vehicle.
In summary, the problems of the prior art are as follows: (1) the traditional automobile controls two steering wheels simultaneously by an integral steering motor, and the automobile with the structure cannot realize larger steering wheel turning angle, so that the defect that the steering radius of the automobile is always larger is caused, and great inconvenience is brought to drivers, road traffic and even social safety.
(2) The traditional automobile controls two steering wheels simultaneously by an integral steering motor, and the structure mode is often difficult to achieve Ackermann steering geometric relationship when the wheels are steered, so that the tread of the steering wheel is inevitably worn too fast, and the service life of the tire can be shortened.
(3) The existing four-wheel steering automobile has complex structural design, and the application range is extremely limited and the use reliability is not high because a plurality of defects in the structural design are not completely solved. Further, as the steering system becomes more complicated, it takes up more space, thereby inevitably squeezing space of other systems to affect its performance.
The difficulty of solving the technical problems is as follows:
(1) in order to avoid the situation of excessively rapid abnormal wear of the tread of the automobile steering wheel, the steering wheel needs to meet the Ackerman steering geometric relationship under each corner. And the traditional mode of connecting and controlling two steering wheels by one steering motor can only realize that the Ackermann steering geometric relationship is satisfied in a certain corner range at most. That is, it is almost impossible for conventional automotive steering to satisfy ackermann steering geometry throughout the entire range of turning angles.
(2) The steering system of the conventional two-wheel steering automobile has been developed for over 100 years, and the steering system has almost come to the utmost without changing modes and principles. That is, it is impossible to achieve a smaller turning radius without changing the fitting relationship and the moving relationship of the two steered wheels.
Currently, some automobile manufacturers have designed four-wheel steering automobiles, and the principle of the four-wheel steering automobiles is that the four wheels are steered independently or the front and rear steering wheels are steered independently so as to achieve a smaller steering radius. The automobile can realize smaller steering radius and even 0-radius steering, but the control strategy is also much more complicated due to the addition of too many steering motors on the automobile, thereby causing higher cost.
The significance of solving the technical problems is as follows: the invention improves the conventional front wheel steering into two wheels which respectively and independently steer on the basis of an in-wheel motor type electric automobile. The invention realizes smaller steering radius on the premise of meeting Ackerman steering geometric relationship by matching different rotating angles of the two front steering wheels and matching different rotating speeds of the two rear wheels. The automobile improved by the invention can greatly reduce the minimum steering radius of the automobile, thereby reducing the range of motion of the automobile during working and improving the maneuverability of the automobile; the method can ensure that the automobile is close to the Ackerman steering geometric relation as much as possible during steering, thereby reducing the tire abrasion of the steering wheel and prolonging the service life; compared with the invented four-wheel steering automobile, the automobile of the invention has much lower manufacturing cost and better practicability.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a novel electric automobile capable of reducing the steering radius, a control system and a control method.
The invention is realized in such a way that a novel electric automobile control method capable of reducing the steering radius comprises the following steps:
step one, detecting the steering angle of a steering wheel through a steering wheel rotation angle sensor; detecting the rolling speed of the driving wheel through a driving wheel rolling angle sensor; detecting the steering angle of the automobile through a steering wheel angle sensor; detecting the size of an accelerator of an engine through an accelerator opening sensor; detecting a gear signal of the automobile through a gear signal sensor; other driving state signals of the automobile are obtained through other sensors.
Step two, the steering control computer receives signals of all sensors, wherein the signals comprise the turning angles α and β of the inner steering wheel and the outer steering wheel and the rolling speeds v of the inner driving wheel and the outer driving wheelInner partAnd vOuter coverThe rotation angle of the steering wheel is analyzed and calculated by the driver, and then the output signal controls the rotation angular speed of two steering motors which then respectively control the rotation angle of two steering wheels, wherein, in the whole process, the computer leads the rotation angles α and β of the two steering wheels to always meet the Ackerman steering geometric relationship, namely cot α -cot β -L through closed-loop controlAB/LAC；
Thirdly, the automobile steering control computer controls the rolling speed v of the inner driving wheel and the outer driving wheel according to the rotating angles α and β of the inner steering wheel and the outer steering wheelInner partAnd vOuter coverThe rotation angle of the steering wheel rotated by the driver, the opening degree of the accelerator of the automobile at the moment, the running state signals of the running gear of the automobile and the like are analyzed and calculated, then signals are output to control the rotating speeds of the two driving motors, and the two driving motors further control the rolling speeds of the two driving wheels respectively. Wherein, the computer leads the rotating speeds v of the two driving wheels to be controlled in a closed loop way in the whole processInner partAnd vOuter coverAlways satisfy the relation vInner part/vOuter cover＝LOC/LOD。
In the first step and the second step, the turning angles α and β of the two steering wheels are continuously increased along with the continuous increase of the turning angle of the steering wheel of the automobile, the steering radius of the automobile is also continuously reduced, and the automobile gradually enters a small-radius steering mode from a conventional steering modeWhen the turning angle of the steering wheel reaches 90 degrees. In the whole steering process, the two steering wheels always meet the Ackermann steering geometric relationship, and simultaneously the two driving wheels also meet the proportional relationship vInner part/vOuter cover＝LOC/LOD。
Further, the turning angle of the steering wheel is gradually increased in the process of turning the steering wheel from small to large. In the process, the steering center of the automobile is always positioned on the axis of the rear wheel of the automobile, and moves from outside to inside along the axis of the rear wheel along the increase of the turning angle, namely the steering radius of the automobile is smaller, and the steering center of the automobile tends to move inwards.
In step two, when the steering angle of the automobile wheels is small, namely the steering angle of the inner steering wheel is smaller than 90 degrees, the automobile is in a conventional steering mode, the steering process of the automobile is consistent with that of a traditional two-wheel steering automobile in the stage, and the computer controls the steering angle relation of the inner steering wheel and the outer steering wheel to meet the requirement that cot α -cot β is L according to the Ackerman steering geometric relationAB/LACWhen the angle of the steering wheel of the automobile is further increased, the steering angle of the inner wheel exceeds 90 degrees and is further increased, and the computer controls the angle of the inner and outer steering wheels to meet the requirement that cot α -cot β is L according to the Ackerman steering geometric relationshipAB/LACAt the moment, the steering of the automobile is in a small-radius steering mode, and the steering circle center of the automobile is located on the inner side of the rear wheel axis.
Furthermore, in the third step, when the rotation angle of the automobile wheel is smaller, namely the automobile is in a conventional steering mode, the steering circle center of the automobile is arranged outside the axis of the inner rear wheel, the control computer controls the hub motor to realize that the two rear wheels roll in the forward direction, the rotating speed of the inner wheel is less than that of the outer wheel, and the speed relationship between the two rear wheels is vInner part/vOuter cover＝LOC/LOD. When the rotation angle of the inner steering wheel reaches the valve value of 90 degrees, the automobile starts to enter a small-radius steering mode, and at the moment, the automobileThe turning circle center is moved to the grounding point of the inner rear wheel, the control computer controls the hub motor to realize that the rotating speed of the outer rear wheel is positive rotation, and the rotating speed of the inner rear wheel is reduced to 0 through the hub motor and the brake. When the rotation angle of the inner side steering wheel exceeds 90 degrees and continues to increase, the automobile belongs to a small-radius steering mode, the steering circle center of the automobile moves to the inner side of the axis of the inner rear wheel, the control computer controls the hub motor to realize that the outer rear wheel rotates in the forward direction, the inner rear wheel rotates in the reverse direction, and the speed relationship of the outer rear wheel and the inner rear wheel is vInner part/vOuter cover＝LOC/LOD。
Another object of the present invention is to provide a novel electric vehicle control system capable of reducing a steering radius, comprising:
the left front steering wheel rotation angle sensor and the right front steering wheel rotation angle sensor are respectively positioned at the left and right positions of the two front wheels and used for detecting the steering angle of the steering wheels;
the left rear driving wheel rolling angle sensor and the right rear driving wheel rolling angle sensor are used for detecting the rolling speed of the driving wheels;
the steering control computer is used for receiving signals of all the sensors, calculating and analyzing the signals, making a judgment, sending corresponding rotating speed instructions to the two steering motors and the hub motor, and finally realizing the small-radius steering of the automobile according with the Ackerman steering geometric characteristics;
the left front steering motor and the right front steering motor are used for driving the two front wheel steering main pins to rotate and driving the side steering wheels to rotate;
the left rear hub motor and the right rear hub motor are used for driving the two rear wheels to realize the rolling of the wheels.
Another object of the present invention is to provide a novel electric vehicle capable of reducing a steering radius, comprising:
the steering wheel comprises a left front wheel and a right front wheel, and the steering of the left front wheel and the steering of the right front wheel are respectively driven by a steering motor to drive a steering main pin to rotate so as to drive the side steering wheel to rotate; the steering motor realizes angular displacement of the steering wheel exceeding 90 degrees; the two steering motors are mutually independent and can rotate reversely;
the driving wheel comprises a left rear wheel and a right rear wheel, and the wheels are driven by a wheel hub motor respectively to roll; the two hub motors are independent from each other and do not influence each other, and the two hub motors can drive in the forward and reverse directions.
It is another object of the present invention to provide a computer program product stored on a computer readable medium, comprising a computer readable program for providing a user input interface to implement the novel steering radius reducible electric vehicle control method when executed on an electronic device.
Another object of the present invention is to provide a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to implement a novel steering radius reduction electric vehicle control method.
In summary, the advantages and positive effects of the invention are: the novel electric automobile capable of reducing the steering radius is provided with two steering motors which respectively and independently control the rotation angles of the steering wheels on the same side, and the two steering motors can more easily achieve the Ackerman steering geometric relationship through the accurate control of a computer.
The automobile steering control computer controls the speed of the two hub motors to realize the active differential speed of the two rear driving wheels according to the rotation angle signals of the two steering wheels and the throttle opening degree and gear position signals of the automobile, and then is matched with the control of the rotation angle of the two steering wheels to realize the switching of the automobile between different steering modes. The steering modes include a normal steering mode and a small-radius steering mode, wherein the normal steering mode is similar to the steering radius of a traditional automobile, and the steering radius of the automobile can be reduced along with the increase of the steering wheel angle until the small-radius steering mode is reached. Compared with the traditional steering mode, the small-radius steering mode can greatly reduce the steering radius of the automobile. The data comparison before and after the modification of the invention is carried out by taking an automobile with a certain wheelbase of 2.8 meters and a wheel base of 1.6 meters as an example, and the results are shown in the following table. The table shows that the minimum turning radius of the automobile improved by the invention is reduced from 5.6m to 3.2m, the moving range of the automobile during working is greatly reduced, and the maneuverability of the automobile is improved.
Figure BDA0002474382060000071
The automobile steering control computer can respectively control the rotation angles of two steering wheels of an automobile and the rolling speeds of two driving wheels of the automobile, and establish the size relationship between the two steering wheels and the rolling speeds of the two driving wheels of the automobile, so that the two steering wheels and the rolling speeds of the two driving wheels of the automobile meet the Ackerman steering geometric relationship at all times. Thereby protecting the tire from abnormal wear to improve the life of the tire and increase the driving stability of the automobile.
Drawings
Fig. 1 is a flowchart of a novel electric vehicle control method capable of reducing a steering radius according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a novel electric vehicle capable of reducing a steering radius according to an embodiment of the present invention.
In the figure: 1. a left front wheel rotation angle sensor; 2. a right front wheel rotation angle sensor; 3. a left wheel roll speed sensor; 4.a right wheel rolling speed sensor; 5. a left steering motor; 6. a right steering motor; 7. a left hub motor; 8. a right hub motor; 9. and a steering control computer.
Fig. 3 is a block diagram of a structure of a novel electric vehicle control system capable of reducing a steering radius according to an embodiment of the present invention.
Fig. 4 is a schematic diagram of a conventional steering mode of an automobile according to an embodiment of the present invention.
Fig. 5 is a schematic steering diagram of the vehicle steering transition from the normal steering mode to the small-radius steering mode according to the embodiment of the invention.
Fig. 6 is a schematic view of a small-radius steering mode of an automobile according to an embodiment of the present invention.
Fig. 7 is a view showing a steering process of the automobile in the conventional steering mode according to the present invention.
FIG. 8 is a diagram of the vehicle steering process during the transition from conventional steering to small radius steering according to the present invention.
Fig. 9 is a view illustrating a steering process of the vehicle in the small radius steering mode according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In view of the problems in the prior art, the present invention provides a novel electric vehicle, a control system and a control method capable of reducing a steering radius, and the present invention is described in detail below with reference to the accompanying drawings.
The steering wheel of the novel electric automobile capable of reducing the steering radius provided by the embodiment of the invention is two front wheels, the steering of the front wheels is realized by driving a steering main pin to rotate by a steering motor, so as to drive the side steering wheel to rotate, and the steering motor can realize the angular displacement of the steering wheel exceeding 90 degrees. The two steering motors are independent of each other, do not influence each other, and can rotate reversely.
The novel driving wheel capable of reducing the steering radius of the electric automobile provided by the embodiment of the invention is two rear wheels which are respectively driven by a wheel hub motor to realize the rolling of the wheel. Two in-wheel motor are independent each other, do not influence each other, and two in-wheel motor can all realize positive and negative two-way drive. The in-wheel motor may also be a drive motor.
As shown in fig. 1, the novel electric vehicle control method capable of reducing the steering radius provided by the embodiment of the invention includes the following steps:
s101, detecting the steering angle of a steering wheel through a steering wheel rotation angle sensor; the rolling speed of the driving wheel is detected by the driving wheel rolling angle sensor.
And S102, the steering control computer receives signals of all the sensors, calculates and analyzes the signals, controls the rotation angle displacement and the speed of the two steering motors according to the rotation angle of the steering wheel rotated by the driver and the Ackerman steering geometric relationship, and further respectively controls the rotation angle of the two steering wheels.
S103, controlling the rolling speed and the rolling direction of the two driving wheels through a steering control computer according to the angular displacement of the steering wheel or the position of the steering circle center of the automobile so as to realize the switching of the automobile between steering modes with different sizes.
Fig. 2 is a schematic structural diagram of a novel electric vehicle capable of reducing a steering radius according to an embodiment of the present invention.
As shown in fig. 3, the novel electric vehicle control system capable of reducing the steering radius provided by the embodiment of the present invention includes: the steering control system comprises a left front steering wheel rotation angle sensor, a right front steering wheel rotation angle sensor, a left rear driving wheel rolling angle sensor, a right rear driving wheel rolling angle sensor, a steering control computer, a left front steering motor, a right front steering motor, a left rear hub motor and a right rear hub motor.
The left front steering wheel rotation angle sensor and the right front steering wheel rotation angle sensor are positioned at two front wheel positions and used for detecting the steering angle of the steering wheels;
the left rear driving wheel rolling angle sensor and the right rear driving wheel rolling angle sensor are used for detecting the rolling speed of the driving wheels;
the steering control computer is used for receiving signals of all the sensors, calculating and analyzing the signals, making a judgment, sending corresponding rotating speed instructions to the two steering motors and the hub motor, and finally realizing the small-radius steering of the automobile according with the Ackerman steering geometric characteristics;
the left front steering motor and the right front steering motor are used for driving the two front wheel steering main pins to rotate so as to drive the side steering wheel to rotate;
the left rear hub motor and the right rear hub motor are used for driving the two rear wheels to realize the rolling of the wheels.
The present invention is further described below in conjunction with the noun explanations.
1. Four-wheel steering: in the invention, all four wheels of the automobile can realize steering.
2. Steering the two wheels: four wheels of the automobile can realize steering only by two front wheels or can realize steering only by two rear wheels. The automobile steering wheel in the invention is two front wheels.
3. Rotation of the wheel: the steering wheel of the automobile can swing in the left-right direction on the ground, and the automobile can be steered through the movement. In the present invention, two front wheels can achieve this motion.
4. And (3) main pin: the steering wheel of a motor vehicle is usually rotated about an axis which, if made as a physical object, is called the kingpin.
5. Rolling of the wheels: the wheels of the automobile rotate on a plane vertical to the axes of the wheels, and the automobile can be driven to advance by the rotation of the wheels. In the present invention, two rear wheels can achieve this motion.
6. A steering motor: the automobile comprises two motors which are used for driving the two steering wheels to rotate around the main pins of the two steering wheels.
7. A hub motor: the automobile comprises two motors which are used for driving the two driving wheels to roll around the axes of the two driving wheels.
8. Ackermann steering geometry: when the automobile is steered, the turning angle of the inner steering wheel is always larger than that of the outer steering wheel due to the fact that the steering radiuses of the left steering wheel and the right steering wheel are different. After the rotation angle size relation of the left and right steering wheels of the automobile meets the Ackerman steering geometric relation, the two steering wheels can realize pure rolling, thereby protecting the tires from abnormal wear and increasing the running stability of the automobile.
9. The automobile steering circle: in the case of a two-wheeled vehicle, the vehicle turns around a virtual circle, which is the steering circle of the vehicle.
10. The automobile steering circle center: the center of the steering circle when the automobile steers.
11. Turning circle of wheels: when each steering wheel of the automobile turns to a certain angle, the automobile can do circular motion around a virtual circle, and the virtual circle is the steering circle of the steering wheel.
12. Turning circle center of the wheel: the center of a steering circle of the automobile steering wheel.
13, α, β refer to the steering angle of the outside and inside wheels, respectively, when the car is turning.
14, A, B, C, D four points: the contact points of the left front wheel, the right front wheel, the left rear wheel and the right rear wheel with the ground are respectively indicated.
The present invention will be further described with reference to the following examples.
The embodiment of the invention provides a novel four-wheel electric automobile capable of reducing the steering radius.
The steering wheel of the automobile provided by the embodiment of the invention is two front wheels, and the steering of the front wheels is realized by driving a steering main pin to rotate by a steering motor so as to drive the side steering wheel to rotate. The two steering motors are independent of each other, do not influence each other, and can rotate reversely.
The driving wheel of the automobile provided by the embodiment of the invention is two rear wheels which are respectively driven by a hub motor to realize the rolling of the wheel. Two in-wheel motors are mutually independent, do not influence each other, and can all realize the antiport. The in-wheel motor may also be a drive motor.
The automobile provided by the embodiment of the invention is provided with a steering control computer (9 in figure 2), two wheel rotation angle sensors (1 and 2 in figure 2), two wheel rolling speed sensors (3 and 4 in figure 2), a steering wheel rotation angle sensor, an accelerator opening sensor, a gear signal sensor (10, 11 and 12 in figure 2) for detecting the driving state of the automobile, two steering motors (5 and 6 in figure 2) for driving the steering wheels to rotate, and two hub motors (7 and 8 in figure 2) for driving the driving wheels to roll. The two wheel rotation angle sensors are positioned at two front wheel positions and used for detecting the steering angle of the steering wheel; the two wheel rolling speed sensors are used for detecting the rolling speed of the driving wheel; the steering control computer is used for receiving signals of all the sensors, calculating and analyzing the signals, then making a judgment and sending corresponding rotating speed instructions to the two steering motors and the hub motor. Finally, the automobile small-radius steering conforming to the Ackerman steering geometric characteristics can be realized.
The automobile provided by the embodiment of the invention is a two-wheel steering two-wheel driving electric automobile. The steering wheel is two front wheels, and the two front wheels are driven by two steering motors respectively to realize steering, and the steering motors can realize angular displacement of the steering wheel exceeding 90 degrees. The driving wheel is two rear wheels which are respectively driven by two hub motors, and the two hub motors can realize forward and reverse bidirectional driving.
The control computer of the automobile provided by the embodiment of the invention mainly realizes two functions:
(1) the steering angle control device can control the displacement size and the speed of the rotation angles of the two steering motors according to the size of the rotation angle of the steering wheel rotated by a driver and the Ackerman steering geometric relationship, and further respectively control the size of the rotation angles of the two steering wheels (according to the Ackerman steering geometric relationship, the sizes of the two steering wheels can be different, and the rotation angle of the steering wheel at the inner side is often larger than that at the outer side). The computer controls the rotation angles of the two steering wheels to always meet the Ackermann steering geometric relationship, so that the final steering circle center of the automobile is located at the intersection of the steering circle centers of the four wheels (namely, the steering circle centers of the four wheels are superposed at the same point, namely the steering circle center of the automobile.
When the steering angle of the automobile wheels is small, the automobile is in a conventional steering mode, and the computer controls the steering angle relation of the inner steering wheel and the outer steering wheel to meet the requirement of cot α -cot β -L according to the Ackerman steering geometric relationAB/LACAs shown in FIG. 4, the steering center of the vehicle is located outside the rear wheel axis, when the steering wheel angle increases until the inner wheel angle reaches 90 degrees, the outer wheel does not reach 90 degrees, the state is shown in FIG. 5, the vehicle begins to enter a small radius steering mode, the steering center of the vehicle is located at the ground contact point of the inner steering wheel, when the steering wheel angle of the vehicle increases further, the steering angle of the inner wheel exceeds 90 degrees and increases further, the computer controls the angles of the inner and outer steering wheels to meet the cot α -cot β -L based on the Ackerman steering geometryAB/LACThe automobile state in the process is shown in fig. 6, the steering of the automobile is in a small-radius steering mode, and the steering center of the automobile is locatedInboard of the rear wheel axis.
(2) The control computer can also control the rolling speed and the rolling direction of the two driving wheels according to the angular displacement of the steering wheel or the position of the steering circle center of the automobile so as to realize the switching of the automobile between steering modes with different sizes. When the rotation angle of the steering wheel is smaller, the steering circle center of the automobile is arranged outside the axis of the inner rear wheel, the control computer controls the hub motor to realize that the two rear wheels roll in the forward direction, the rotation speed of the inner wheel is smaller than that of the outer wheel, and the speed relationship between the two rear wheels is vInner part/vOuter cover＝LOC/LODAt this time, the vehicle is in the same steering mode as the conventional vehicle, and the steering radius is large, which is the conventional steering mode (as shown in fig. 4). When the rotation angle of the steering wheel is increased to a certain set threshold value, the rotation angle of the inner side steering wheel reaches 90 degrees, the steering circle center of the automobile moves to the grounding point of the inner rear wheel (namely, the point O is overlapped with the point C in the figure 5), the control computer controls the hub motor to realize that the rotation speed of the outer rear wheel is positive rotation, the rotation speed of the inner rear wheel is reduced to 0 (the speed is reduced by the hub motor and the brake), at the moment, the automobile steering is separated from a conventional steering mode, and the automobile starts to enter a small-radius steering mode (as shown in figure 5). When the rotation angle of the steering wheel exceeds a set threshold value and continues to increase, the rotation angle of the steering wheel also continues to increase, the steering circle center of the automobile moves to the inner side of the axis of the inner rear wheel, the control computer controls the hub motor to realize that the outer rear wheel rotates in the forward direction and the inner rear wheel rotates in the reverse direction, and the speed relationship between the outer rear wheel and the inner rear wheel is vInner part/vOuter cover＝LOC/LODIn the process, the automobile belongs to a small-radius steering mode (as shown in fig. 6).
When the steering wheel is turned from small to large, the turning state of the automobile is changed from the state shown in fig. 4 to the state shown in fig. 6, the turning center of the automobile moves from inside to outside along the axis of the rear wheel in the changing process, and the turning radius of the automobile is also changed from large to small. And when the steering center moves to the middle position of the two rear wheels, the steering radius of the automobile is minimum. This minimum steering radius is considerably reduced compared to conventional two-wheeled vehicles, so that an improvement in the mobility and passing ability of the vehicle can be achieved.
Fig. 7 is a view showing a steering process of the automobile in the conventional steering mode according to the present invention.
FIG. 8 is a diagram of the vehicle steering process during the transition from conventional steering to small radius steering according to the present invention.
Fig. 9 is a view illustrating a steering process of the vehicle in the small radius steering mode according to the present invention.
It should be noted that the embodiments of the present invention can be realized by hardware, software, or a combination of software and hardware. The hardware portion may be implemented using dedicated logic; the software portions may be stored in a memory and executed by a suitable instruction execution system, such as a microprocessor or specially designed hardware. Those skilled in the art will appreciate that the apparatus and methods described above may be implemented using computer executable instructions and/or embodied in processor control code, such code being provided on a carrier medium such as a disk, CD-or DVD-ROM, programmable memory such as read only memory (firmware), or a data carrier such as an optical or electronic signal carrier, for example. The apparatus and its modules of the present invention may be implemented by hardware circuits such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of hardware circuits and software, e.g., firmware.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (8)

1. The novel electric automobile control method capable of reducing the steering radius is characterized by comprising the following steps of:
step one, detecting the steering angle of a steering wheel through a steering wheel rotation angle sensor; detecting the rolling speed of the driving wheel through a driving wheel rolling angle sensor;
secondly, the steering control computer receives signals of all the sensors, calculates and analyzes the signals, controls the rotation angle displacement and the speed of the two steering motors according to the rotation angle of the steering wheel rotated by the driver and the Ackerman steering geometric relationship, and respectively controls the rotation angle of the two steering wheels;
and step three, controlling the rolling speed and the rolling direction of the two driving wheels through a steering control computer according to the angular displacement of the steering wheel or the position of the steering circle center of the automobile, and realizing the switching of the automobile between steering modes with different sizes.
2. The method as claimed in claim 1, wherein in step two, the steering angle of the vehicle wheels is small, the vehicle is in a conventional steering mode, and the computer controls the rotation angle relationship of the inner and outer steering wheels to satisfy cot α -cot β -L according to the ackermann steering geometry relationshipAB/LACThe steering circle center of the automobile is positioned on the outer side of the rear wheel axis;
the angle of the steering wheel is increased until the angle of the inner side wheel reaches 90 degrees and the angle of the outer side wheel does not reach 90 degrees, the automobile enters a small-radius steering mode, and the steering circle center of the automobile is positioned at the grounding point of the inner side steering wheel;
the angle of the steering wheel of the automobile is further increased, the steering angle of the inner side wheel exceeds 90 degrees and is further increased, and the computer controls the angle of the inner side steering wheel and the outer side steering wheel to meet the requirement that cot α -cot β is L according to the Ackerman steering geometrical relationAB/LACThe steering of the automobile is in a small-radius steering mode, and the steering circle center of the automobile is located on the inner side of the rear wheel axis.
3. The method as claimed in claim 1, wherein in step three, when the steering wheel has a small rotation angle, the center of the steering wheel is outside the axis of the inner and the rear wheels, the control computer controls the hub motor to roll the two rear wheels in the forward direction, and the rotation speed of the inner wheel is lower than that of the outer wheelThe rotational speed and the speed relationship of the two are vInner part/vOuter cover＝LOC/LOD；
When the rotation angle of the steering wheel is increased to a certain set threshold value, the rotation angle of the inner side steering wheel reaches 90 degrees, the steering circle center of the automobile moves to the grounding point of the inner rear wheel, the control computer controls the hub motor to realize that the rotation speed of the outer rear wheel is positive rotation, the rotation speed of the inner rear wheel is reduced to 0 through the hub motor and the brake, the automobile steering is separated from a conventional steering mode, and the automobile starts to enter a small-radius steering mode.
4. The method as claimed in claim 1, wherein in step three, when the rotation angle of the steering wheel exceeds the predetermined threshold and continues to increase, the rotation angle of the steering wheel continues to increase, the center of the steering circle of the vehicle moves to the inner side of the axle line of the inner rear wheel, the control computer controls the hub motor to rotate the outer rear wheel in the forward direction and the inner rear wheel in the reverse direction, and the relationship between the speeds of the outer rear wheel and the inner rear wheel is vInner part/vOuter cover＝LOC/LODIn the process, the automobile belongs to a small-radius steering mode;
in the process of turning the steering wheel from small to large, the steering center of the automobile moves from inside to outside along the axis of the rear wheel, and the steering radius of the automobile also decreases from large to small; when the steering center moves to the middle position of the two rear wheels, the steering radius of the automobile is minimum.
5. A novel steering radius reducible electric vehicle control system of the novel steering radius reducible electric vehicle control method according to any one of claims 1 to 4, characterized by comprising:
the left front steering wheel rotation angle sensor and the right front steering wheel rotation angle sensor are respectively positioned at the left and right positions of the two front wheels and used for detecting the steering angle of the steering wheels;
the left rear driving wheel rolling angle sensor and the right rear driving wheel rolling angle sensor are used for detecting the rolling speed of the driving wheels;
the steering control computer is used for receiving signals of all the sensors, calculating and analyzing the signals, making a judgment, sending corresponding rotating speed instructions to the two steering motors and the hub motor, and finally realizing the small-radius steering of the automobile according with the Ackerman steering geometric characteristics;
the left front steering motor and the right front steering motor are used for driving the two front wheel steering main pins to rotate and driving the side steering wheels to rotate;
the left rear hub motor and the right rear hub motor are used for driving the two rear wheels to realize the rolling of the wheels.
6. A novel steering radius reducible electric vehicle of the novel steering radius reducible electric vehicle control method according to any one of claims 1 to 4, characterized in that the novel steering radius reducible electric vehicle comprises:
the steering wheel comprises a left front wheel and a right front wheel, and the steering of the left front wheel and the steering of the right front wheel are respectively driven by a steering motor to drive a steering main pin to rotate so as to drive the side steering wheel to rotate; the steering motor realizes angular displacement of the steering wheel exceeding 90 degrees; the two steering motors are mutually independent and can rotate reversely;
the driving wheel comprises a left rear wheel and a right rear wheel, and the wheels are driven by a wheel hub motor respectively to roll; the two hub motors are independent from each other and do not influence each other, and the two hub motors can drive in the forward and reverse directions.
7. A computer program product stored on a computer readable medium, comprising a computer readable program for providing a user input interface to implement the novel steering radius reducible electric vehicle control method of any one of claims 1 to 5 when executed on an electronic device.
8. A computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the novel steering radius reducible electric vehicle control method of any one of claims 1 to 5.
CN202010358825.6A 2020-04-29 2020-04-29 Novel electric automobile capable of reducing steering radius, control system and control method Pending CN111497932A (en)

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CN112373450A (en) * 2020-11-10 2021-02-19 上海拿森汽车电子有限公司 Control method and device for vehicle auxiliary turning
CN114056421A (en) * 2021-12-17 2022-02-18 江西洪都航空工业集团有限责任公司 Two-drive two-steering motion control system for unmanned vehicle
CN114771654A (en) * 2022-04-07 2022-07-22 东风柳州汽车有限公司 Automobile steering control method and device, terminal equipment and storage medium
CN116461607A (en) * 2023-05-12 2023-07-21 爱搏特科技(深圳)有限公司 Distributed drive-by-wire and steering-by-wire method and related device

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CN112373450A (en) * 2020-11-10 2021-02-19 上海拿森汽车电子有限公司 Control method and device for vehicle auxiliary turning
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CN116461607B (en) * 2023-05-12 2024-02-06 爱搏特科技(深圳)有限公司 Distributed drive-by-wire and steering-by-wire method and related device

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