CN107792168B - Sleeve motor steer-by-wire device and control method - Google Patents

Abstract

The invention discloses a sleeve motor wire-controlled steering device and a control method. The wire-controlled steering device includes a steering wheel, a steering column connected to the steering wheel, a left wheel steering transmission mechanism connected to the left wheel, and a steering transmission mechanism connected to the right wheel. The connected right wheel steering transmission mechanism, and the mechanical steering transmission mechanism connected to the steering column through the electromagnetic clutch, the steering column is connected to the road sense/power-assist motor through the reducer, the steering device also includes a steering-by-wire actuator The steering-by-wire actuator includes a first sleeve motor, a second sleeve motor, and a planetary roller screw mechanism driven by the first sleeve motor and/or the second sleeve motor. The invention adopts a double sleeve motor and a planetary roller screw mechanism, makes full use of the axial space of the rack and the tie rod protective sleeve to reduce the radial size of the motor, and has high transmission efficiency, which is easy to improve the double sleeve motor during heavy load operation. Drive consistency.

Description

A sleeve motor wire-controlled steering device and control method

Technical field

The invention relates to the technical field of automobile parts, and in particular to automobile steering-by-wire technology.

Background technique

Automobile intelligence is developing rapidly, and steer-by-wire is a key link in the development of automobile intelligence, especially one of the necessary technologies for driverless driving. Steer-by-wire technology has gradually matured and has been applied to a small number of models. The steering-by-wire system requires redundancy and fault-tolerance functions. It not only requires software to implement diagnosis and fault-tolerant control algorithms, but also requires hardware redundancy design, resulting in complex hardware layout of the steering-by-wire system, high cost, and low hardware utilization.

There have been many studies on steer-by-wire technology. Among them, the dual-motor redundant steer-by-wire system designed by Infiniti has been successfully applied in the Q50 real car. This system is designed with motor tachometers at the left and right ends of the rack to drive the steering gear pinions. , drives the rack to move left and right. When the clutch fails, the clutch is closed. The left steering gear pinion is connected to the mechanical steering column to achieve steering. However, the redundant structure of the system is complex. Both motors are driven by the reducer through the rack and pinion steering gear to steer sideways. Pull rod, low transmission efficiency. South Korea's Hyundai Motor Company proposed a steering-by-wire device and method for a dual-motor drive rack (Patent No. US201600144890A1). This system did not solve the problem of motor space installation and the steering mode of dual-motor failure. Becker et al. proposed an electro-hydraulic steering-by-wire system (Patent No. US20160068182A1). This device controls the pressure of the steering wheel cylinder through two motor pumps and drives the tie rods on both sides to move left and right. However, the response speed of the motor to establish hydraulic pressure is slow. The high-pressure oil pipeline has unreliable factors such as increased oil leakage and the presence of bubbles, and it is impossible to achieve direct mechanical connection after the steering-by-wire failure. A hybrid steering-by-wire system invented by Yang Lin et al. (Patent No. 201610989594.2). This system separates the road-sensing motor and the power-assist motor. Only one set of steering actuator motors are used to drive the double-row planetary gear reducer, which is then driven by the worm rack. The tie rod moves left and right, and the steering wheel and steering wheel have real-time controllable force transmission characteristics and angular transmission characteristics. When the system fails, it returns to the mechanical steering state through the clutch, but the system has a complex structure and low transmission efficiency. Yu Leiyan designed an electric vehicle steering-by-wire system and control method (Patent No. 201310649410.4). The system designed a steering wheel force feedback motor and a worm reducer to simulate road feel. The steering motor and planetary gear reducer drive the steering gear. The gear realizes steering, and a motor and a planetary gear reducer are installed near the steering gear, which requires more layout space. The transmission through the rack and pinion steering gear reduces the working efficiency of the motor and cannot achieve the steering mode in which the motor fails.

In summary, the existing steer-by-wire system has contradictions between low transmission efficiency, complex structure and difficult spatial arrangement, as well as redundant and failure working mode requirements.

Contents of the invention

The technical problem to be solved by the present invention is to provide a sleeve motor wire-controlled steering device with compact structure, high transmission efficiency and reliable steering.

In order to solve the above technical problems, the present invention adopts the following technical solution: a sleeve motor-by-wire steering device, including a steering wheel, a steering column connected to the steering wheel, a left wheel steering transmission mechanism connected to the left wheel, and a right steering wheel. The right wheel steering transmission mechanism is connected to the wheel, and the mechanical steering transmission mechanism is connected to the steering column through the electromagnetic clutch. The steering column is connected to the road sense/power-assist motor through the reducer. The steering device also includes a steer-by-wire system. The steering-by-wire actuator includes a first sleeve motor, a second sleeve motor, and a planetary roller screw mechanism driven by the first sleeve motor and/or the second sleeve motor. When the electromagnetic clutch absorbs In the closed state, the mechanical steering transmission mechanism drives the left wheel steering transmission mechanism and the right wheel steering transmission mechanism to drive the left wheel and the right wheel to rotate. When the electromagnetic clutch is disconnected, the planetary roller wire The lever mechanism drives the left wheel steering transmission mechanism and the right wheel steering transmission mechanism to drive the left wheel and the right wheel to rotate.

Preferably, the planetary roller screw mechanism includes a screw, a gear roller engaged with the screw, and a first internal ring gear and a second internal ring gear simultaneously engaged with the gear roller.

Preferably, the first internal ring gear is integrated with the first sleeve motor rotor, and the second internal ring gear is integrated with the second sleeve motor rotor.

Preferably, the mechanical steering transmission mechanism includes a steering gear pinion and a rack for meshing transmission, and the steering gear pinion is connected to the steering column through an electromagnetic clutch.

Preferably, the left wheel steering transmission mechanism includes a left tie rod connected to the rack, a left trapezoidal arm connected to the left tie rod, and a left steering knuckle connected to the left trapezoidal arm. The left steering knuckle is connected to the left wheel. connection, the right wheel steering transmission mechanism includes a right tie rod connected to the rack, a right trapezoidal arm connected to the right tie rod, a right steering knuckle connected to the right trapezoid arm, the right steering knuckle is connected to the right wheel .

The invention also provides a sleeve motor wire-controlled steering control method, which includes the following working modes:

First, the car’s steering-by-wire mode for medium and low speed driving:

The electromagnetic clutch is disconnected, and the electronic control unit controls the first sleeve motor and the second sleeve motor to rotate forward, driving the left wheel and the right wheel through the planetary roller screw mechanism, the left wheel steering transmission mechanism, and the right wheel steering transmission mechanism. The side wheels rotate to realize the driver's steering intention, and at the same time, the electronic control unit controls the forward rotation of the road feel/power-assist motor to provide the driver with a suitable road feel;

Second, the car’s high-speed steering-by-wire mode:

The electromagnetic clutch is disconnected, and the electronic control unit controls the forward transmission of the first sleeve motor, which drives the left and right wheels to rotate through the planetary roller screw mechanism, the left wheel steering transmission mechanism, and the right wheel steering transmission mechanism to achieve driving. According to the driver's steering intention, the electronic control unit controls the reverse rotation of the second sleeve motor to provide high-speed steering damping force to ensure the car's high-speed driving stability. The electronic control unit controls the forward rotation of the road sense/power-assist motor to provide the driver with a suitable road feel;

Third, the wire control turns to redundant mode:

The electromagnetic clutch is disconnected and when the electronic control unit diagnoses that one of the sleeve motors is working abnormally, it cuts off the power of the abnormal motor and controls the normal working sleeve motor to rotate forward. Through the planetary roller screw mechanism, the left wheel steering transmission mechanism, and the right wheel The steering transmission mechanism drives the left and right wheels to rotate to realize the driver's steering intention, and the electronic control unit controls the forward rotation of the road feel/power-assist motor to provide the driver with a suitable road feel;

Fourth, the steering-by-wire failure mode:

The electromagnetic clutch is closed, and the electronic control unit cuts off the power of the first sleeve motor and the second sleeve motor. The electronic control unit controls the road sense/power-assist motor to reverse and provide steering assistance through the mechanical steering transmission mechanism and the left wheel steering transmission mechanism. , The right wheel steering transmission mechanism drives the left wheel and right wheel to rotate to realize the driver's steering intention.

The present invention adopts the above technical solution and has the following beneficial effects:

1. Compact structure and easy to arrange: This invention adopts a double sleeve motor and a planetary roller screw mechanism, making full use of the axial space of the rack and tie rod protective sleeve to reduce the radial size of the motor without increasing the motor deceleration near the steering gear. mechanism, the traditional mechanical steering system layout can be used;

2. High transmission efficiency: The invention adopts a planetary roller screw mechanism, which has high transmission efficiency and is easy to improve the driving consistency of the double-sleeve motor during heavy load operation. It does not need to directly drive the rack and steering tie rod through the steering gear, and also Can improve transmission efficiency;

3. Stable high-speed driving: The present invention can ensure the smooth steering by wire process by controlling the precise displacement of the rack. When the car is running at high speed, the second sleeve motor reverses to provide steering damping force, thereby improving the stability of the car's steering;

4. Reliable steering: The present invention uses a double sleeve motor to achieve hardware structural redundancy, and an electromagnetic clutch and steering column to achieve mechanical steering when the wire control fails, ensuring the reliability of the steering system.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

Figure 1 is a schematic diagram of the principle of a sleeve motor-by-wire steering device of the present invention;

Figure 2 is a schematic diagram of the principle of the steering-by-wire actuator in a sleeve motor steering-by-wire device of the present invention;

Figure 3 is a flow chart of a sleeve motor-by-wire steering control method of the present invention.

In the picture, 1-steering wheel, 2-steering wheel sensor, 3-steering column, 4-reducer, 5-electromagnetic clutch, 6-electronic control unit, 7-road sense/power-assist motor, 8-left wheel, 9- Left steering knuckle, 10-left trapezoidal arm, 11-left tie rod, 12-rack, 13-steering gear pinion, 14-wire-controlled steering actuator, 15-first sleeve motor, 16-lead screw, 17 -Planetary roller screw mechanism, 18-second sleeve motor, 19-right tie rod, 20-right trapezoidal arm, 21-right steering knuckle, 22-right wheel, 23-stator coil of first sleeve motor , 24-the first sleeve motor rotor, 25-the first internal ring gear, 26-the gear roller, 27-the stator coil of the second sleeve motor, 28-the second sleeve motor rotor, 29-the second internal teeth lock up.

Detailed ways

It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application or uses. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

As shown in Figures 1 and 2, a car steering device includes a steering wheel 1, a steering wheel sensor 2 and a steering column 3 connected to the steering wheel 1, a left wheel steering transmission mechanism connected to the left wheel 8, and a steering wheel to the right. The right wheel steering transmission mechanism is connected to the wheel 22, and the mechanical steering transmission mechanism is connected to the steering column 3 through the electromagnetic clutch 5. The steering column 3 is connected to the road sensing/power-assist motor 7 through the reducer 4.

In addition, the automobile steering device also includes a steering-by-wire actuator 14 . The steering-by-wire actuator 14 includes a first sleeve motor 15, a second sleeve motor 18, and a planetary roller screw mechanism 17 driven by the first sleeve motor 15 and/or the second sleeve motor 18. When the electromagnetic clutch 5 is engaged, the mechanical steering transmission mechanism drives the left wheel steering transmission mechanism and the right wheel steering transmission mechanism to drive the left wheel 8 and the right wheel 22 to rotate. When the electromagnetic clutch 5 is disconnected, , the mechanical steering transmission mechanism does not interact with the left wheel steering transmission mechanism and the right wheel steering transmission mechanism. The planetary roller screw mechanism 17 drives the left wheel steering transmission mechanism and the right wheel steering transmission mechanism to drive the left wheel. 8 and the right wheel 22 rotates.

In this embodiment, the planetary roller screw mechanism 17 includes a screw 16, a gear roller 26 meshing with the screw 16, and a first internal gear 25 and a second internal gear 25 meshing with the gear roller 26. Circle 29. The first sleeve motor 15 includes a stator coil 23 of the first sleeve motor and a first sleeve motor rotor 24 . The second sleeve motor 18 includes a stator coil 27 of the second sleeve motor and a second sleeve motor rotor 28 . Furthermore, the first internal ring gear 25 is integrated with the first sleeve motor rotor 24, and the second internal ring gear 29 is integrated with the second sleeve motor rotor 28 to facilitate later assembly.

The mechanical steering transmission mechanism includes a steering gear pinion 13 and a rack 12 for meshing transmission. The steering gear pinion 13 is connected to the steering column 3 through an electromagnetic clutch 5. The left wheel steering transmission mechanism includes a gear rack and a steering gear. 12 connected to the left tie rod 11, the left trapezoidal arm 10 connected to the left tie rod 11, the left steering knuckle 9 connected to the left trapezoidal arm 10, the left steering knuckle 9 is connected to the left wheel 8, the right wheel The steering transmission mechanism includes a right tie rod 19 connected to the rack 12, a right trapezoid arm 20 connected to the right tie rod 19, and a right steering knuckle 21 connected to the right trapezoid arm 20. The right steering knuckle 21 is connected to the right wheel 22 Connection, the rack 12 is connected to the lead screw 16.

In addition, based on the above-mentioned automobile steering-by-wire device, the present invention also proposes a corresponding steering-by-wire control method. As shown in Figure 3, the electronic control unit (ECU) 6 collects the torque and angle signals of the steering wheel sensor 2, the vehicle speed signal, Yaw angular velocity signal, and rack displacement signal, and perform system fault diagnosis based on steering wheel angle, rack displacement and motor current to determine whether there is a fault. If there is a single motor fault, it is necessary to indicate which motor is faulty or both motors are faulty. The fault will enter the steering-by-wire redundancy mode and the steering-by-wire failure mode respectively; if the motor status is normal, it will enter the vehicle's medium-low speed steering-by-wire mode and the vehicle's high-speed driving steering-by-wire mode respectively, depending on whether the vehicle speed reaches 80km/h. Therefore, the steering-by-wire control method proposed by the present invention includes the following working modes:

1. Steering-by-wire mode for medium and low speed driving:

The electronic control unit 6 issues a command and the electromagnetic clutch 5 is disconnected. The electronic control unit 6 recognizes the driver's steering intention through the steering wheel angle and torque signals, uses the displacement of the rack 12 as a feedback signal, and applies vehicle dynamics theory based on the vehicle speed and yaw angular velocity to calculate the drive current of the sleeve motor, and inputs the average to The stator coil 23 of the first sleeve motor and the stator coil 27 of the second sleeve motor, the first sleeve motor rotor 24 drives the integrally manufactured first internal ring gear 25 to rotate forward, and the second sleeve motor rotor 28 drives The integrally manufactured second internal ring gear 29 rotates forward and provides steering torque at the same time. The first ring gear 25 and the second ring gear 29 drive the gear roller 26 to rotate at the same time, and the screw 16, which is equivalent to the sun gear of the planetary reducer, can be regarded as fixed if it does not rotate in the circumferential direction. Therefore, the motor torque passes through the planetary roller. After the column screw mechanism 17 decelerates and increases torque, it is output by the gear roller 26. The rotation of the gear roller 26 is converted into the translation of the screw 16. The left side passes through the rack 12, the left tie rod 11, the left trapezoidal arm 10, the left The steering knuckle 9 drives the left wheel 8 to rotate, and the right side drives the right wheel 22 to rotate through the right tie rod 19, right trapezoidal arm 20, and right steering knuckle 21. At the same time, the electronic control unit 6 estimates the rack force based on the displacement of the rack 12, calculates the back-aligning torque and the current required for road feel, controls the current of the road feel/assist motor 7, and provides the driver with steering road feel.

2. Car steering-by-wire mode for high-speed driving:

The electronic control unit 6 issues a command and the electromagnetic clutch 5 is disconnected. The electronic control unit 6 identifies the driver's steering intention through the steering wheel angle and torque signals, uses the displacement of the rack 12 as a feedback signal, and applies vehicle dynamics theory to calculate the driving current and damping force required for the sleeve motor based on the vehicle speed and yaw angular velocity. The magnitudes are respectively input to the stator coil 23 of the first sleeve motor and the stator coil 27 of the second sleeve motor, then the first sleeve motor rotor 24 drives the integrally manufactured first internal ring gear 25 to rotate forward to provide steering torque, and The second sleeve motor rotor 28 drives the integrally manufactured second internal ring gear 29 to reversely provide damping force. The first ring gear 25 drives the gear roller 26 to rotate, and the second ring gear 29 can be used as a load limiting steering overshoot. That is, the motor torque is decelerated and increased by the planetary roller screw mechanism 17 and then output by the gear roller 26. The rotation of the gear roller 26 is converted into the translation of the screw 16. The left side drives the left wheel 8 to rotate through the rack 12, the left tie rod 11, the left trapezoidal arm 10, and the left steering knuckle 9, and the right side drives the left wheel 8 to rotate through the right tie rod 19. , the right trapezoid arm 20 and the right steering knuckle 21 drive the right wheel 22 to rotate. At the same time, the electronic control unit 6 estimates the rack force based on the displacement of the rack 12, calculates the back-aligning torque and the current required for road feel, controls the current of the road feel/assist motor 7, and provides the driver with steering road feel.

3. Steer-by-wire redundant mode:

When the electronic control unit 6 diagnoses that one of the sleeve motors is working abnormally, it cuts off the power supply of the abnormal motor and controls the normal working sleeve motor to rotate forward.

Take the failure of the first sleeve motor 15 as an example. The electronic control unit 6 issues a command, the electromagnetic clutch 5 is disconnected, and the first sleeve motor 15 is powered off. The electronic control unit 6 recognizes the driver's steering intention through the steering wheel angle and torque signals, uses the displacement of the rack 12 as a feedback signal, and applies vehicle dynamics theory according to the vehicle speed and yaw angular velocity to calculate the current of the second sleeve motor 18 and inputs it to The stator coil 27 of the second sleeve motor and the second sleeve motor rotor 28 drive the integrally manufactured second internal ring gear 29 to rotate forward to provide steering torque. The second internal ring gear 29 drives the gear roller 26 to rotate, that is, the motor torque is decelerated and increased by the planetary roller screw mechanism 17 and then output by the gear roller 26 to convert the rotation of the gear roller 26 into the translation of the screw 16 , the left side drives the left wheel 8 to rotate through the rack 12, the left tie rod 11, the left trapezoid arm 10, and the left steering knuckle 9, and the right side drives the right wheel through the right tie rod 19, the right trapezoid arm 20, and the right steering knuckle 21 22 turns. At the same time, the electronic control unit 6 estimates the rack force based on the displacement of the rack 12, calculates the back-aligning torque and the current required for road feel, controls the current of the road feel/assist motor 7, and provides the driver with steering road feel.

4. Steering-by-wire failure mode:

When the power fails, the electromagnetic clutch 5 is normally closed and engaged, and the steering column 3 and the steering gear pinion 13 are mechanically connected through the electromagnetic clutch 5, and the steer-by-wire system returns to the traditional mechanical steering system. When both motors fail or the sensor fails, the electronic control unit 6 issues a command, the electromagnetic clutch 5 is powered off and engaged, and the first sleeve motor 15 and the first sleeve motor 18 are powered off. The electronic control unit 6 calculates the current required for power assist through the steering wheel angle/torque signal and the vehicle speed signal, controls the reverse current of the road sense/power assist motor 7, and drives the reducer 4 to provide steering assist. The driver's steering torque passes through the steering wheel 1 to the steering column 3 and is superimposed with the assist torque of the road sense/power-assist motor 7. It is transmitted to the steering gear pinion 13 through the electromagnetic clutch 5, driving the rack 12 through the left tie rod 11, left trapezoidal arm 10, The left steering knuckle 9 drives the left wheel 8 to rotate, and the right side drives the right wheel 22 to rotate via the lead screw 16, right tie rod 19, right trapezoidal arm 20, and right steering knuckle 21.

At the same time, it needs further explanation that the present invention proposes a corresponding steering-by-wire control method based on the sleeve motor steering-by-wire device. Among them, how to calculate the ideal rack displacement from the steering wheel angle, torque, vehicle speed and yaw angular velocity? , how to control the current size of the first sleeve motor and the second sleeve motor, and how to control the current size of the road feel/power-assist motor to provide the driver with a suitable road feel. Those skilled in the art can use the content disclosed in the present invention and combine it with the specific vehicle model. Parameters are specifically studied and calculated.

Since the gear roller 26 does not translate but only rotates, the displacement of the rack 12 is equal to the displacement of the screw 16. Therefore, the displacement of the rack 12 can be calculated by measuring the rotation angle of the internal ring gear.

In addition, the electronic control unit 6 collects the torque and angle signals, vehicle speed signal, yaw angular velocity signal, and rack displacement signal of the steering wheel sensor 2, and performs system fault diagnosis based on the steering wheel angle, rack displacement, and motor current to determine the sleeve motor Whether there is a fault or not belongs to conventional technical means in this field and will not be described again here.

In this embodiment, the critical point between low-speed and high-speed driving is 80 km/h. Of course, those skilled in the art can understand that it can also be increased or decreased to a certain extent in practice.

In addition to the above preferred embodiments, the present invention has other embodiments. Those skilled in the art can make various changes and deformations according to the present invention. As long as they do not deviate from the spirit of the present invention, they should all fall within the scope of the invention as defined in the claims. scope.

Claims (5)

1. A sleeve motor steer-by-wire control method, which controls a sleeve motor steer-by-wire device, the steering device comprises a steering wheel, a steering column connected with the steering wheel, a left wheel steering transmission mechanism connected with left wheels, a right wheel steering transmission mechanism connected with right wheels, and a mechanical steering transmission mechanism connected with the steering column through an electromagnetic clutch, the steering column is connected with a road feel/power-assisted motor through a speed reducer, the steering device also comprises a steer-by-wire executing mechanism, the steer-by-wire executing mechanism comprises a first sleeve motor, a second sleeve motor and a planetary roller screw mechanism driven by the first sleeve motor and/or the second sleeve motor, the mechanical steering transmission mechanism drives the left wheel steering transmission mechanism and the right wheel steering transmission mechanism to act so as to drive the left wheels and the right wheels to rotate in an electromagnetic clutch suction state, and the planetary roller screw mechanism drives the left wheel steering transmission mechanism and the right wheel steering transmission mechanism to act so as to drive the left wheels and the right wheels to rotate in an electromagnetic clutch suction state;

the control method is characterized by comprising the following working modes:

first, a steering-by-wire mode of low-speed driving in an automobile:

the electromagnetic clutch is disconnected, the electric control unit controls the first sleeve motor and the second sleeve motor to rotate positively, the left wheel and the right wheel are driven to rotate through the planetary roller screw mechanism, the left wheel steering transmission mechanism and the right wheel steering transmission mechanism, the steering intention of a driver is realized, and meanwhile, the electric control unit controls the road sense/power-assisted motor to rotate positively, so that the proper road sense of the driver is provided;

secondly, a steering-by-wire mode of high-speed running of the automobile:

the electromagnetic clutch is disconnected, the electric control unit controls the first sleeve motor to forward drive, the planetary roller screw mechanism, the left wheel steering transmission mechanism and the right wheel steering transmission mechanism drive the left wheel and the right wheel to rotate, the steering intention of a driver is realized, the electric control unit controls the second sleeve motor to reverse, a high-speed steering damping force is provided, the high-speed running stability of the automobile is ensured, the electric control unit controls the road sense/booster motor to forward rotate, and the appropriate road sense of the driver is provided;

third, steer-by-wire redundancy mode:

when the electromagnetic clutch is disconnected, the electric control unit diagnoses that one sleeve motor works abnormally, cuts off the power supply of the abnormal motor, controls the normal working sleeve motor to rotate positively, drives the left wheel and the right wheel to rotate through the planetary roller screw mechanism, the left wheel steering transmission mechanism and the right wheel steering transmission mechanism, realizes the steering intention of a driver, controls the road sense/power-assisted motor to rotate positively, and provides the driver with proper road sense;

fourth, steer-by-wire failure mode:

the electromagnetic clutch is closed, the electric control unit cuts off the power supply of the first sleeve motor and the second sleeve motor, the electric control unit controls the road sense/power assisting motor to reversely rotate, steering power is provided, and the left wheel and the right wheel are driven to rotate through the mechanical steering transmission mechanism and the left wheel steering transmission mechanism and the right wheel steering transmission mechanism, so that the steering intention of a driver is realized.

2. The sleeve motor steer-by-wire control method of claim 1, wherein: the planetary roller screw mechanism comprises a screw, a gear roller meshed with the screw, and a first annular gear and a second annular gear meshed with the gear roller.

3. The sleeve motor steer-by-wire control method of claim 2, wherein: the first annular gear is integrated with the first sleeve motor rotor, and the second annular gear is integrated with the second sleeve motor rotor.

4. The sleeve motor steer-by-wire control method of claim 1, wherein: the mechanical steering transmission mechanism comprises a steering gear pinion and a rack which are in meshed transmission, and the steering gear pinion is connected with a steering column through an electromagnetic clutch.

5. The sleeve motor steer-by-wire control method of claim 4, wherein: the left side wheel steering transmission mechanism comprises a left transverse pull rod connected with the rack, a left trapezoid arm connected with the left transverse pull rod, and a left steering knuckle connected with the left trapezoid arm, wherein the left steering knuckle is connected with the left side wheel, the right side wheel steering transmission mechanism comprises a right transverse pull rod connected with the rack, a right trapezoid arm connected with the right transverse pull rod, and a right steering knuckle connected with the right trapezoid arm, and the right steering knuckle is connected with the right side wheel.