阅读说明：本技术 一种线控转向系统及其控制方法、装置、控制设备及汽车 (Wire-controlled steering system, control method and device thereof, control equipment and automobile ) 是由 丁皓阳 白艳飞 徐鸿飞 袁志博 于 2020-06-05 设计创作，主要内容包括：本发明提供了一种线控转向系统及其控制方法、装置、控制设备及汽车,所述线控转向系统包括：设置于车辆转向轮上的转向模块,转向模块包括扭矩转角传感器、转向电机、行星齿轮机构和转向附件；其中,转向电机通过转向输入轴连接行星齿轮机构,行星齿轮机构通过转向输出轴和转向附件连接轮毂电机,扭矩转角传感器设置在转向输入轴或转向输出轴上；与转向电机连接的线控转向控制器；通过整车通讯网络与线控转向控制器连接的力矩传感器和方向盘转角传感器。上述方案,提供了一种集成在轮毂电机中的线控转向系统,提升了轮毂电机汽车的集成度,实现了车辆360°转向,还提升了车辆转向角控制精度,优化了自动驾驶控制基于转角控制的高级功能。(The invention provides a steer-by-wire system, a control method, a control device and an automobile, wherein the steer-by-wire system comprises: the steering module is arranged on a steering wheel of the vehicle and comprises a torque corner sensor, a steering motor, a planetary gear mechanism and a steering accessory; the steering motor is connected with the planetary gear mechanism through the steering input shaft, the planetary gear mechanism is connected with the hub motor through the steering output shaft and the steering accessory, and the torque and angle sensor is arranged on the steering input shaft or the steering output shaft; the steer-by-wire controller is connected with the steering motor; a torque sensor and a steering wheel angle sensor which are connected with the steer-by-wire controller through the whole vehicle communication network. According to the scheme, the wire control steering system integrated in the hub motor is provided, the integration level of an automobile with the hub motor is improved, 360-degree steering of the automobile is realized, the control precision of the steering angle of the automobile is improved, and the advanced function of automatic driving control based on corner control is optimized.)

1. A steer-by-wire system for mounting on a vehicle having an in-wheel motor, comprising:

the steering module is arranged on a steering wheel of the vehicle and comprises a torque corner sensor, a steering motor, a planetary gear mechanism and a steering accessory; the steering motor is connected with the planetary gear mechanism through a steering input shaft, the planetary gear mechanism is connected with the hub motor through a steering output shaft and the steering accessory, and the torque and angle sensor is arranged on the steering input shaft or the steering output shaft;

the steer-by-wire controller is connected with the steering motor;

and the torque sensor and the steering wheel corner sensor are connected with the steer-by-wire controller through a whole vehicle communication network.

2. The steer-by-wire system of claim 1, wherein the steering accessory comprises a steering arm, a yoke, and/or a shock absorber; wherein, the steering arm and the fork arm are connected with the steering output shaft and the hub motor.

3. A control method applied to the steer-by-wire system according to any one of claims 1 to 2, characterized by comprising:

acquiring a torque signal of a vehicle steering wheel acquired by a torque sensor and a corner signal of the vehicle steering wheel acquired by a steering wheel corner sensor;

determining a first rotation angle according to the torque signal and the rotation angle signal;

when the first turning angle is larger than a preset angle, acquiring a current vehicle speed, and determining a first target turning angle according to the current vehicle speed;

controlling a steering motor to output the first target corner;

acquiring a steering shaft signal acquired by a torque corner sensor;

and adjusting the first target corner according to the steering shaft signal to obtain a second target corner, and controlling the steering motor to output the second target corner.

4. The control method according to claim 3, characterized by further comprising:

and when the first rotating angle is smaller than the preset angle, determining that the first target rotating angle is the first rotating angle.

5. The control method according to claim 3, wherein the acquiring a current vehicle speed when the first rotation angle is larger than a preset angle, and determining a first target rotation angle according to the current vehicle speed comprises:

when the current vehicle speed is 0, determining that the first target corner is the first corner;

when the current vehicle speed is greater than a first preset speed, determining the first target corner as a first preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle; wherein the first preset speed is greater than 0;

when the current vehicle speed is greater than 0 and less than the first preset speed, sending request information to a first controller, and determining the first target corner according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information.

6. The control method according to claim 5, characterized in that when the current vehicle speed is greater than 0 and less than the first preset speed, request information is sent to a first controller, and the first target steering angle is determined according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information, and includes:

when the current vehicle speed is greater than 0 and less than the first preset speed, sending request information for entering a large-angle steering mode to the first controller;

when an allowing signal fed back by the first controller according to the request information is received, determining the first target corner to be a second preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle;

and under the large-angle steering mode, the running speed of the vehicle is less than or equal to a second preset speed, and the second preset speed is less than the first preset speed.

7. The control method of claim 6, wherein the first controller comprises an Advanced Driving Assistance System (ADAS) controller or a chassis domain controller.

8. A control device applied to the steer-by-wire system according to any one of claims 1 to 2, characterized by comprising:

the first acquisition module is used for acquiring a torque signal of a vehicle steering wheel acquired by a torque sensor and a corner signal of the vehicle steering wheel acquired by a steering wheel corner sensor;

a rotation angle determination module for determining a first rotation angle according to the torque signal and the rotation angle signal;

the target corner module is used for acquiring the current vehicle speed when the first corner is larger than a preset angle, and determining a first target corner according to the current vehicle speed;

the first control module is used for controlling the steering motor to output the first target corner;

the second acquisition module is used for acquiring steering shaft signals acquired by the torque angle sensor;

and the second control module is used for adjusting the first target corner according to the steering shaft signal to obtain a second target corner and controlling the steering motor to output the second target corner.

9. The control device according to claim 8, characterized by further comprising:

and the third control module is used for determining the first target corner as the first corner when the first corner is smaller than the preset angle.

10. The control device according to claim 8, wherein the target steering angle module includes:

the first control submodule is used for determining the first target corner as the first corner when the current vehicle speed is 0;

the second control submodule is used for determining the first target corner as a first preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle when the current vehicle speed is greater than the first preset speed; wherein the first preset speed is greater than 0;

the third control sub-module is used for sending request information to the first controller when the current vehicle speed is greater than 0 and less than the first preset speed, and determining the first target corner according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information.

11. The control device of claim 10, wherein the third control sub-module comprises:

the request unit is used for sending request information for entering a large-angle steering mode to the first controller when the current vehicle speed is greater than 0 and less than the first preset speed;

the control unit is used for determining the first target corner as a second preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle when receiving an allowance signal fed back by the first controller according to the request information;

and under the large-angle steering mode, the running speed of the vehicle is less than or equal to a second preset speed, and the second preset speed is less than the first preset speed.

12. A control device comprising a memory, a processor, and a program stored on the memory and executable on the processor; characterized in that the processor implements the control method according to any one of claims 3 to 7 when executing the program.

13. A motor vehicle, characterized by comprising a control device according to any one of claims 8 to 11.

Technical Field

The invention relates to the field of automobiles, in particular to a wire-controlled steering system, a control method and device thereof, control equipment and an automobile.

Background

At present, for a traditional vehicle, a clutch, a transmission shaft, a differential and even a transfer case are necessary, the components are heavy, the structure of the vehicle is more complex, the problems of failure rate and periodic maintenance are also existed, and the hub motor can well solve the problems.

The wheel hub motor technology is also called as wheel built-in motor technology, and the most important characteristic of the wheel hub motor technology is that a power system, a transmission system and even a braking system are integrated into a wheel hub, so that the mechanical part of an electric vehicle is greatly simplified, a large number of transmission parts are omitted, and the vehicle structure is simpler. In addition, the vehicle driven by the hub motor can obtain better space utilization rate and higher transmission efficiency, and meanwhile, the friction loss can be reduced by about 10 percent because no transmission mechanisms such as a main transmission gear, a differential gear, a transmission shaft and the like are arranged.

The hub motor has the characteristic of independent driving of a single wheel, so that the hub motor can be easily realized in a front-driving mode, a rear-driving mode or a four-driving mode. Meanwhile, the hub motor can realize differential steering similar to a crawler vehicle through different rotating speeds and even reverse rotation of the left wheel and the right wheel, the turning radius of the vehicle can be obviously reduced, even pivot steering can be completed, and the steering performance under a specific vehicle working condition is greatly improved compared with that of a traditional vehicle.

At present, the hub motor belongs to the leading-edge technology in the automobile industry, and particularly has wider application prospect in the field of new energy automobiles. Currently, the mainstream hub motors are divided into two types: an inner rotor type and an outer rotor type. Wherein, the outer rotor type wheel hub adopts a low-speed outer rotor motor, the highest rotating speed of the motor is 1000-1500r/min, no speed reducer is provided, and the rotating speed of the wheel is the same as that of the motor; the inner rotor type adopts a high-speed inner rotor motor, a speed reducer with a fixed transmission ratio is arranged, and the rotating speed of the motor can reach 10000r/min in order to obtain higher power density.

However, the above two hub motors are designed by integrating the power system, the transmission system and the brake system of the vehicle (some of the hub motors do not have the brake system). The steering system, which is the most critical subsystem for the overall operation of the vehicle, is generally not included, and the conventional steering system mounted on the auxiliary frame is still adopted. Referring now to fig. 1, a schematic view of a typical in-wheel motor vehicle steering system is shown, wherein the steering linkage is configured in accordance with the steering system that is currently in widespread use.

Because a Steering system is not integrated in a hub motor with a mainstream structure at present, a moment is required to be transmitted by a driving wheel of a traditional Steering system (including a mainstream wire-controlled Electric Power Steering (EPS)), and a Steering pull rod is limited by a vehicle arrangement structure, so that two coaxial wheels cannot be driven to rotate at different angles, and the wheels cannot rotate 360 degrees along a main pin axis, so that 360-degree full-angle Steering cannot be realized in a true sense.

Disclosure of Invention

The embodiment of the invention provides a wire-controlled steering system, a control method and device thereof, control equipment and an automobile, and aims to solve the problems that a steering system is not integrated with a hub motor and the steering range of the automobile is limited in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

according to an aspect of the present invention, there is provided a steer-by-wire system mounted on a vehicle having an in-wheel motor, comprising:

the steering module is arranged on a steering wheel of the vehicle and comprises a torque corner sensor, a steering motor, a planetary gear mechanism and a steering accessory; the steering motor is connected with the planetary gear mechanism through a steering input shaft, the planetary gear mechanism is connected with the hub motor through a steering output shaft and the steering accessory, and the torque and angle sensor is arranged on the steering input shaft or the steering output shaft;

the steer-by-wire controller is connected with the steering motor;

and the torque sensor and the steering wheel corner sensor are connected with the steer-by-wire controller through a whole vehicle communication network.

Optionally, the steering attachment comprises a steering arm, a yoke and/or a shock absorber; wherein, the steering arm and the fork arm are connected with the steering output shaft and the hub motor.

According to another aspect of the present invention, there is provided a control method applied to the steer-by-wire system described above, including:

acquiring a torque signal of a vehicle steering wheel acquired by a torque sensor and a corner signal of the vehicle steering wheel acquired by a steering wheel corner sensor;

determining a first rotation angle according to the torque signal and the rotation angle signal;

when the first turning angle is larger than a preset angle, acquiring a current vehicle speed, and determining a first target turning angle according to the current vehicle speed;

controlling a steering motor to output the first target corner;

acquiring a steering shaft signal acquired by a torque corner sensor;

and adjusting the first target corner according to the steering shaft signal to obtain a second target corner, and controlling the steering motor to output the second target corner.

Optionally, the method further comprises:

and when the first rotating angle is smaller than the preset angle, determining that the first target rotating angle is the first rotating angle.

Optionally, when the first turning angle is greater than a preset angle, acquiring a current vehicle speed, and determining a first target turning angle according to the current vehicle speed includes:

when the current vehicle speed is 0, determining that the first target corner is the first corner;

when the current vehicle speed is greater than a first preset speed, determining the first target corner as a first preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle; wherein the first preset speed is greater than 0;

when the current vehicle speed is greater than 0 and less than the first preset speed, sending request information to a first controller, and determining the first target corner according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information.

Optionally, when the current vehicle speed is greater than 0 and less than the first preset speed, sending a request message to a first controller, and determining the first target corner according to the received feedback message; wherein the feedback information is information sent by the first controller according to the request information, and includes:

when the current vehicle speed is greater than 0 and less than the first preset speed, sending request information for entering a large-angle steering mode to the first controller;

when an allowing signal fed back by the first controller according to the request information is received, determining the first target corner to be a second preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle;

and under the large-angle steering mode, the running speed of the vehicle is less than or equal to a second preset speed, and the second preset speed is less than the first preset speed.

Optionally, the first controller comprises an advanced driving assistance system, ADAS, controller or a chassis domain controller.

According to another aspect of the present invention, there is provided a control apparatus applied to the steer-by-wire system as described above, including:

the first acquisition module is used for acquiring a torque signal of a vehicle steering wheel acquired by a torque sensor and a corner signal of the vehicle steering wheel acquired by a steering wheel corner sensor;

a rotation angle determination module for determining a first rotation angle according to the torque signal and the rotation angle signal;

the target corner module is used for acquiring the current vehicle speed when the first corner is larger than a preset angle, and determining a first target corner according to the current vehicle speed;

the first control module is used for controlling the steering motor to output the first target corner;

the second acquisition module is used for acquiring steering shaft signals acquired by the torque angle sensor;

and the second control module is used for adjusting the first target corner according to the steering shaft signal to obtain a second target corner and controlling the steering motor to output the second target corner.

Optionally, the method further comprises:

and the third control module is used for determining the first target corner as the first corner when the first corner is smaller than the preset angle.

Optionally, the target turning angle module includes:

the first control submodule is used for determining the first target corner as the first corner when the current vehicle speed is 0;

the second control submodule is used for determining the first target corner as a first preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle when the current vehicle speed is greater than the first preset speed; wherein the first preset speed is greater than 0;

the third control sub-module is used for sending request information to the first controller when the current vehicle speed is greater than 0 and less than the first preset speed, and determining the first target corner according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information.

Optionally, the third control sub-module comprises:

the request unit is used for sending request information for entering a large-angle steering mode to the first controller when the current vehicle speed is greater than 0 and less than the first preset speed;

the control unit is used for determining the first target corner as a second preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle when receiving an allowance signal fed back by the first controller according to the request information;

and under the large-angle steering mode, the running speed of the vehicle is less than or equal to a second preset speed, and the second preset speed is less than the first preset speed.

According to another aspect of the present invention, there is provided a control apparatus comprising a memory, a processor, and a program stored on the memory and executable on the processor; the processor implements the control method as described above when executing the program.

According to another aspect of the present invention, there is provided an automobile including the control apparatus as described above.

The invention has the beneficial effects that:

above-mentioned scheme provides a drive-by-wire steering system of integration in-wheel motor, has further promoted the integrated level of in-wheel motor car, and has realized 360 turning to of vehicle with a comparatively simple structure. In addition, the control precision of the steering angle of the vehicle can be improved, the advanced function of the automatic driving control based on the steering angle control, such as the precision of a Highway assisted driving function (HWA) or a Traffic Jam assisted automatic driving function (TJP), and the realization capability of an ideal driving track, can be optimized.

Drawings

FIG. 1 is a schematic view of a typical in-wheel motor vehicle steering system of the prior art;

FIG. 2 shows a schematic view of a steer-by-wire system (single wheel) based on an in-wheel motor according to an embodiment of the present invention;

FIG. 3 shows a schematic of a planetary gear mechanism that may be used in a steer-by-wire system provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of a control method provided by an embodiment of the invention;

fig. 5 shows an overall architecture of a steer-by-wire system provided by an embodiment of the present invention;

FIG. 6 is a schematic view of a steer-by-wire control scheme provided by an embodiment of the present invention;

FIG. 7 shows a schematic diagram of a conventional steer-by-wire system of the prior art;

fig. 8 is a schematic diagram of a control device according to an embodiment of the present invention.

Description of reference numerals:

1-a hub motor; 2-a steering tie rod; 3-a diverter; 4-a whole vehicle frame; 01-steer-by-wire controller; 001-steering motor; 002-planetary gear mechanism; 003-steering input shaft; 004-steering output shaft; 005-steering arm; 006-yoke; 0021-sun gear; 0022-a planet carrier; 0023-a gear ring; 0024-planetary gear.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

The invention provides a wire-controlled steering system, a control method and a control device thereof, control equipment and an automobile, aiming at the problems that a steering system is not integrated with a hub motor and the steering range of the automobile is limited in the prior art.

As shown in fig. 1, one embodiment of the present invention provides a steer-by-wire system mounted on a vehicle having an in-wheel motor 1, including:

the steering module is arranged on a steering wheel of the vehicle and comprises a torque angle sensor, a steering motor 001, a planetary gear mechanism 002 and a steering accessory; wherein the steering motor 001 is connected with the planetary gear mechanism 002 through a steering input shaft 003, the planetary gear mechanism 002 is connected with the hub motor 1 through a steering output shaft 004 and the steering accessory, and the torque rotation angle sensor is arranged on the steering input shaft 003 or the steering output shaft 004;

a steer-by-wire controller 01 connected to the steering motor 001;

and the torque sensor and the steering wheel angle sensor are connected with the steer-by-wire controller 01 through a whole vehicle communication network.

It should be noted that, as shown in fig. 2, a steering system based on an in-wheel motor according to an embodiment of the present invention is shown, and the steering system also belongs to a steer-by-wire system. The steer-by-wire system comprises a steering module, a steer-by-wire controller 01 and 3 subsystem modules of a steering wheel module, wherein the steering module comprises a torque angle sensor, a steering motor 001, a planetary gear mechanism 002, a steering accessory and the like; the steering wheel module comprises a steering wheel assembly, a steering wheel corner sensor, a torque sensor and a steering wheel aligning torque motor. The planetary gear mechanism 002 is fixed to the entire vehicle, for example, may be fixedly connected to the entire vehicle frame 4.

According to the steer-by-wire system provided by one embodiment of the present invention, a two-wheel steering architecture or a four-wheel steering architecture or a six-wheel steering architecture can be arbitrarily combined. A set of steering motor 001 and a transmission mechanism are arranged for each steering wheel, namely, one steering module is independently arranged on each steering wheel of the vehicle; in terms of control, each steering motor 001 can share one steer-by-wire controller 01, and the steer-by-wire controller 01 can be connected with a driver through a whole vehicle communication network, so that torque connection between the driver and the steer-by-wire controller 01 is isolated. Further, since a mechanical connection such as a steering column is eliminated between the steering wheel and the steering gear 3 of the steer-by-wire system, it is necessary to provide a steering wheel return torque motor, i.e., a motor for simulating return. That is, the steering wheel aligning torque motor is used to simulate road feel, and the control of the road feel feedback simulation part is input from the torque angle sensor of the steering module.

Optionally, the steering attachment comprises a steering arm 005, yoke 006 and/or shock absorber; wherein the steering arm 005 and the yoke 006 connect the steering output shaft 004 and the in-wheel motor 1.

It should be noted that the steering attachment includes a mechanical connection, and that shock absorbers and/or shock springs may be integrated. The mechanical coupling structure may include a steering arm 005 and a yoke 006, or other mechanical structures that may be used to couple the steering output shaft 004 and the in-wheel motor 1 to transmit torque, and may rotate about the steering output shaft 004.

The difference between the steer-by-wire system and the mainstream steer-by-wire system provided by the embodiment of the invention is as follows:

firstly, the mechanical actuating mechanism of the steer-by-wire system is different from the mainstream steer-by-wire system, and is mainly embodied in that the steer-by-wire system does not need structures such as gear and rack meshing, worm gear and worm, tie rod and the like.

Secondly, each steering motor 001 of the steer-by-wire system can work independently without mutual influence. That is, even if the front/rear wheels are the same, they can be rotated by different angles, respectively.

Thirdly, the steer-by-wire system is integrated in the hub motor 1, most of mechanical structures of the main flow steer-by-wire system are eliminated, and the torque transmission mechanism can adopt a planetary gear mechanism 002 to transmit torque.

Finally, the greatest difference between the overall structure of the steering system of the in-wheel motor 1 and a main-stream steer-by-wire device is that a planetary gear mechanism 002 is used for replacing mechanisms such as a turbine, a worm, a rack, an inner pull rod, an outer pull rod and a ball head, and the transmission efficiency is improved while the mechanical structure is greatly reduced.

It should be further noted that the steer-by-wire systems on the market are not integrated on the hub motor 1, that is, the conventional steer-by-wire system transmits an electric signal command to the power-assisted motor, so as to control the steer-by-wire system. The working principle of the conventional steer-by-wire system is shown in fig. 7, a sensor for detecting the absolute position of the steering angle of a steering wheel directly transmits a signal to a control unit on a steering machine, and the control unit converts the signal into an angle which the wheels should rotate according to the input angle of the steering wheel, so that a motor is controlled to operate, and the steering machine is driven to realize steering action.

From the integration point of view, compared with the conventional steer-by-wire system which is not integrated on the hub motor 1, the steer-by-wire system provided by the embodiment of the present invention has the following advantages:

the steering-by-wire system is integrated in the hub motor 1, so that most of mechanical structures of a main flow steering-by-wire device are eliminated, and the integration level is higher;

each steering wheel rotates independently and does not influence each other. Compared with the dual redundancy design of the traditional steer-by-wire system, the steer-by-wire system can achieve at least 4 times of redundancy design (under the condition that each wheel is a steering wheel, the steer-by-wire systems on the steering wheels are mutually redundant);

the functional safety performance is improved;

the wheels can rotate by 360 degrees, so that the whole vehicle can rotate in place and move laterally completely, and great convenience and advantages are provided for the movement of the vehicle in a narrow space;

in addition, at present, the automatic driving control of the whole vehicle mostly adopts track control, but the traditional steering system can only rotate the coaxial wheels at the same angle, and can not accurately drive according to the track fitted by the upper automatic driving system. The steer-by-wire system provided by the embodiment of the invention does not have the problem, and the steer-by-wire system based on the hub motor has natural advantages in the aspect of following an ideal driving track.

The steering control system integrates two front edge technologies of steer-by-wire and a hub motor, so that each steering wheel of the vehicle can independently move and the function of 360-degree steering is realized. In addition, the steer-by-wire system provided by the embodiment of the invention can not only be used for the wheel hub motor in the application, but also be carried on a whole vehicle platform which can provide the steer-by-wire system in the patent and has no hard connection of wheels.

It should be noted that, compared with a general gear transmission mechanism, the planetary gear mechanism 002 has the advantages of large power range, high transmission efficiency, accurate transmission ratio, long service life, small structural volume and stable operation. This application can select planetary gear mechanism 002 as the drive mechanism who turns to motor 001, can also choose for use the multirow planetary gear mechanism who adds electronic gear shifting structure to realize that the variable drive ratio turns to. The planetary gear mechanism 002 has a plurality of types, different types can be selected according to the actual required transmission ratio or mechanical efficiency of the whole vehicle, and the planetary gear mechanism 002 can be combined with a fixed-axis gear train to form a composite gear train. Since the planetary gear mechanism 002 is more varied, for convenience of illustration, the embodiment of the present invention only shows one possible planetary gear mechanism 002, and the planetary gear mechanism 002 is a single-row single-stage planetary gear mechanism, as shown in fig. 3. Wherein, planetary gear mechanism 002 includes sun gear 0021, planet carrier 0022, planetary gear 0024 and ring gear 0023, planetary gear mechanism 002 is fixed with whole car through outer ring gear 0023, and its driving member (being sun gear 0021) is connected turn to input shaft 003, follower (being planet carrier 0022) are connected turn to output shaft 004. In addition to the planetary gear mechanism 002, other types of planetary gear mechanisms 002 may be employed, such as single-row planetary gears, multi-row or multi-stage planetary gears, and multi-row planetary gear mechanisms with electrically variable gear ratios, which are different in the driving/driven relationship, and simpler gear transmission or belt transmission mechanisms may be employed.

In the embodiment of the invention, the wire control steering system integrated in the hub motor further improves the integration level of the hub motor automobile, and can realize the 360-degree steering function of the automobile by adopting a simpler structure. In addition, the control precision of the steering angle of the vehicle can be improved, the high-grade functions of the automatic driving control based on the steering angle control, such as the precision of a highway auxiliary driving function HWA or a traffic jam auxiliary automatic driving function TJP, and the realization capability of an ideal driving track, can be optimized.

The embodiment of the invention also provides a control method which is applied to the steer-by-wire system. The steer-by-wire system adopts a control architecture of centralized control and four-wheel (or multi-wheel) distributed output to realize 360-degree four-wheel (or multi-wheel) cooperative steering, and as shown in fig. 5, steering drive motors of each wheel of the steer-by-wire system share one steer-by-wire controller 01. Considering that the steering by 360 degrees influences the longitudinal control and the transverse control of the whole vehicle, the steer-by-wire system not only needs to have an execution function, but also can independently complete the steering work under a specific working condition.

It should be noted that under the working condition of medium-high speed driving of the vehicle, in view of the safety angle of the entire vehicle driving, the large-angle steering is an extremely dangerous operation, so that the steering angle range of the steer-by-wire controller 01 needs to be limited at medium-high speed (for example, the working condition that the vehicle speed is above 20 km/h) to ensure the safety of the vehicle; in the low-speed Driving condition of the vehicle, the steering at a large angle is relatively safe, but in consideration of the complex condition, the operation still has a large risk, so an upper-layer controller is needed to cooperate with the confirmation of the surrounding vehicle condition information and the road condition information and the control of the vehicle speed so as to ensure the safety of the vehicle, and the upper-layer controller comprises an Advanced Driving Assistance System (ADAS) controller or a chassis area controller and the like.

That is, it is necessary to control the steering angle range of the steer-by-wire system according to the current vehicle speed of the vehicle to ensure the safety of the vehicle. Specifically, as shown in fig. 4, the control method includes:

s41: acquiring a torque signal of a vehicle steering wheel acquired by a torque sensor and a corner signal of the vehicle steering wheel acquired by a steering wheel corner sensor;

s42: determining a first rotation angle according to the torque signal and the rotation angle signal;

s43: when the first turning angle is larger than a preset angle, acquiring a current vehicle speed, and determining a first target turning angle according to the current vehicle speed;

s44: controlling the steering motor 001 to output the first target rotation angle;

s45: acquiring a steering shaft signal acquired by a torque corner sensor;

s46: and adjusting the first target rotation angle according to the steering shaft signal to obtain a second target rotation angle, and controlling the steering motor 001 to output the second target rotation angle.

That is, when the driver turns the steering wheel, the torque sensor may collect a torque signal of the vehicle steering wheel, and the steering wheel angle sensor may collect an angle signal of the vehicle steering wheel, from which the current steering intention of the driver, i.e., the first target angle desired by the driver, may be learned. And then judging whether the driver requires steering at a large angle or steering at a small angle according to the first target turning angle. The "large angle" and "small angle" steering intentions can be distinguished according to the preset angle, and the preset angle can be obtained by calibration, for example, the preset angle can be set to 40 degrees by setting the wheel rotation to be in a large angle range of more than 40 degrees.

In addition, because the state of the running vehicle is changed at any time, during the steering process of the vehicle, the shaft signals (namely the steering shaft signals) collected by the torque steering angle sensors on the steering wheels can be monitored, and the output torque and the target steering angle of each motor can be continuously adjusted.

Optionally, the method further comprises:

and when the first rotating angle is smaller than the preset angle, determining that the first target rotating angle is the first rotating angle.

That is, when the driver wants to obtain a ' small angle ' steering, the steer-by-wire system can be controlled to directly follow the driver's intention and output the required steering angle. When the driver wants to obtain a 'large angle' steering, the driver further controls the steering according to the following strategy:

optionally, when the first turning angle is greater than a preset angle, acquiring a current vehicle speed, and determining a first target turning angle according to the current vehicle speed includes:

and when the current vehicle speed is 0, determining that the first target steering angle is the first steering angle.

That is to say, when the vehicle is in the stationary state, the vehicle is in a relatively safe state, and the driver can control the steering range by himself, and the driver can steer according to own will.

It should be noted that, when the current vehicle speed is 0, that is, when the vehicle is in the pivot steering condition, the steer-by-wire system independently completes the pivot steering operation. However, in order to enable the driver to intuitively perceive the moving direction of the vehicle, the steering angle information of each wheel, which is collected by the torque steering angle sensor in the steering module of each wheel, can be transmitted to the whole vehicle communication network through the steer-by-wire controller 01 and converted into a visualized result. For example, the predicted vehicle motion trajectory at the current steering wheel position may be projected on a center control screen to prompt the driver.

When the current vehicle speed is greater than a first preset speed, determining the first target corner as a first preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle; wherein the first preset speed is greater than 0.

That is, when the current vehicle speed is greater than the first preset speed, i.e., under a medium-high speed condition (e.g., a condition above 20 km/h), the wide-angle steering may have an extremely dangerous effect, the steering angle range of the steer-by-wire controller 01 should be limited, and the safety function may be assumed by an upper controller (e.g., an ADAS controller or a chassis area controller), or may be assumed by the steer-by-wire controller 01. Specifically, under medium-high speed working conditions, dead points can be set in a smaller safety angle range, and one or more dead points can be set to respectively correspond to different speed ranges. Namely, the corresponding relation between the vehicle speed and the preset angle can be established by setting the dead point. For example, a rotation angle corresponding to a dead point is set to 15 ° when the speed is in the range of 70km/h to 80km/h, and a rotation angle corresponding to a dead point is set to 10 ° when the speed is in the range of 90km/h to 120 km/h.

When the current vehicle speed is greater than 0 and less than the first preset speed, sending request information to a first controller, and determining the first target corner according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information.

That is, when the vehicle runs at a relatively low speed, the cooperation of the first controller (i.e., the upper controller) is required to control the steering range, so as to ensure the steering safety of the vehicle.

In addition, when the steering wheel is steered at a low speed and a large pivot angle, the rotating range of the steering wheel and the aligning force setting output by the steering wheel road feel simulation module need to be considered, and the steering wheel road feel simulation module is limited by software in a mode of setting a dead point. Meanwhile, the corresponding aligning force is gradually increased before reaching the soft dead center of the steering wheel so as to fit the hand feeling of the common automobile steering wheel as much as possible.

Optionally, when the current vehicle speed is greater than 0 and less than the first preset speed, sending a request message to a first controller, and determining the first target corner according to the received feedback message; wherein the feedback information is information sent by the first controller according to the request information, and includes:

when the current vehicle speed is greater than 0 and less than the first preset speed, sending request information for entering a large-angle steering mode to the first controller;

when an allowing signal fed back by the first controller according to the request information is received, determining the first target corner to be a second preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle;

and under the large-angle steering mode, the running speed of the vehicle is less than or equal to a second preset speed, and the second preset speed is less than the first preset speed.

It should be noted that when the current vehicle speed is greater than 0 and less than the first preset speed, that is, under a low-speed condition, the upper controller needs to be requested to enter a large-angle steering mode. And the upper layer controller confirms the surrounding vehicle condition information and road condition information and limits the current vehicle speed before entering a large-angle steering mode. Limiting the current vehicle speed means limiting the current vehicle speed to a certain value, that is, after receiving the request message, the upper controller needs to control the speed to be below a second preset speed, and then sends the permission signal to the steer-by-wire controller 01, so as to ensure the safety of vehicle steering. Wherein, the second preset speed can be obtained by calibration, for example, can be set to 10 km/h. The wide-angle steering operation in response to the driver is permitted after being permitted to enter the wide-angle steering mode. Further, the vehicle speed in the wide-angle steering mode can be set to be constant at a second preset speed, for example, the vehicle speed in the wide-angle steering mode can be set to be constant at 5km/h, so as to achieve a better safety effect.

Optionally, the first controller comprises an advanced driving assistance system, ADAS, controller or a chassis domain controller.

The control schematic of the steer-by-wire system is shown in fig. 6, that is, the whole control process can be roughly divided into the following three stages:

stage one: the driver turns the steering wheel, i.e. the driver exerts a circumferential torque on the steering wheel. The torque (namely torque signal) is collected by a torque sensor in the steering wheel module, the rotating angle (namely rotating angle signal) of the steering wheel is collected by a steering wheel rotating angle sensor in the steering wheel module, the torque signal and the rotating angle signal reach a steer-by-wire controller 01 through a whole vehicle communication network, if the rotating angle is a small-angle rotating angle, the steering of the angle is directly executed, and if the rotating angle is a large-angle rotating angle, the steering enters a second stage;

and a second stage: if the steering angle can be completely executed, the steering-by-wire controller 01 obtains the respective rotating angles of two or more steering wheels required for the intention of a driver, then sends the target steering angle to each steering wheel, monitors shaft signals collected by a torque steering angle sensor on each steering wheel in the steering process of the vehicle, and continuously adjusts the output torque and the target steering angle of each motor. When the speed is low, the steer-by-wire controller 01 needs to enter a large-angle turning mode when being allowed by an upper controller through request/confirmation information interaction with the upper controller, and then steering is controlled.

And a third stage: the steering motor 001 receives an instruction sent by the steer-by-wire controller 01, and drives the planetary gear mechanism 002 to drive the steering arm 005 to realize the rotation of the hub motor 1 and the wheels, so that the whole vehicle can steer in any direction.

It can be seen that the steer-by-wire system of the present application is significantly different from the prior art, and specifically, the following table analysis can be seen:

in the embodiment of the invention, a steering system and a hub motor system are highly integrated, and a plurality of mechanical connection structures in a mainstream steering system (including a typical steer-by-wire system) are eliminated, so that each steering wheel can rotate independently without mutual influence; compared with the dual redundancy design of a typical steer-by-wire system, the redundancy design of the steer-by-wire system is at least 4 times (an independent steering subsystem can be carried on the hub motor 1 of each wheel), the redundancy of the steer-by-wire system is greatly improved, and the reliability of the whole vehicle is improved; each wheel can independently rotate, so that the steering system has obvious advantages in the aspect of accurately realizing the ideal running track of the vehicle by matching with an automatic driving platform.

As shown in fig. 8, an embodiment of the present invention further provides a control device, which is applied to the steer-by-wire system described above, and includes:

the first acquisition module 81 is used for acquiring a torque signal of a vehicle steering wheel acquired by a torque sensor and a steering angle signal of the vehicle steering wheel acquired by a steering wheel angle sensor;

a rotation angle determination module 82 for determining a first rotation angle based on the torque signal and the rotation angle signal;

the target corner module 83 is configured to obtain a current vehicle speed when the first corner is larger than a preset angle, and determine a first target corner according to the current vehicle speed;

a first control module 84, configured to control the steering motor 001 to output the first target rotation angle;

the second obtaining module 85 is used for obtaining a steering shaft signal collected by the torque angle sensor;

and the second control module 86 is configured to adjust the first target rotation angle according to the steering shaft signal to obtain a second target rotation angle, and control the steering motor 001 to output the second target rotation angle.

That is, when the driver turns the steering wheel, the torque sensor may collect a torque signal of the vehicle steering wheel, and the steering wheel angle sensor may collect an angle signal of the vehicle steering wheel, from which the current steering intention of the driver, i.e., the first target angle desired by the driver, may be learned. And then judging whether the driver requires steering at a large angle or steering at a small angle according to the first target turning angle. The "large angle" and "small angle" steering intentions can be distinguished according to the preset angle, and the preset angle can be obtained by calibration, for example, the preset angle can be set to 40 degrees by setting the wheel rotation to be in a large angle range of more than 40 degrees.

In addition, because the state of the running vehicle is changed at any time, during the steering process of the vehicle, the shaft signals (namely the steering shaft signals) collected by the torque steering angle sensors on the steering wheels can be monitored, and the output torque and the target steering angle of each motor can be continuously adjusted.

Optionally, the method further comprises:

and the third control module is used for determining the first target corner as the first corner when the first corner is smaller than the preset angle.

That is, when the driver wants to obtain a ' small angle ' steering, the steer-by-wire system can be controlled to directly follow the driver's intention and output the required steering angle. When the driver wants to obtain a 'large angle' steering, the driver further controls the steering according to the following strategy:

optionally, the target turning angle module 83 includes:

and the first control sub-module is used for determining that the first target steering angle is the first steering angle when the current vehicle speed is 0.

That is to say, when the vehicle is in the stationary state, the vehicle is in a relatively safe state, and the driver can control the steering range by himself, and the driver can steer according to own will.

The second control submodule is used for determining the first target corner as a first preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle when the current vehicle speed is greater than the first preset speed; wherein the first preset speed is greater than 0.

That is, when the current vehicle speed is greater than the first preset speed, i.e., under a medium-high speed condition (e.g., a condition above 20 km/h), the wide-angle steering may have an extremely dangerous effect, the steering angle range of the steer-by-wire controller 01 should be limited, and the safety function may be assumed by an upper controller (e.g., an ADAS controller or a chassis area controller), or may be assumed by the steer-by-wire controller 01. Specifically, under medium-high speed working conditions, dead points can be set in a smaller safety angle range, and one or more dead points can be set to respectively correspond to different speed ranges. Namely, the corresponding relation between the vehicle speed and the preset angle can be established by setting the dead point. For example, a rotation angle corresponding to a dead point is set to 15 ° when the speed is in the range of 70km/h to 80km/h, and a rotation angle corresponding to a dead point is set to 10 ° when the speed is in the range of 90km/h to 120 km/h.

The third control sub-module is used for sending request information to the first controller when the current vehicle speed is greater than 0 and less than the first preset speed, and determining the first target corner according to the received feedback information; wherein the feedback information is information sent by the first controller according to the request information.

That is, when the vehicle runs at a relatively low speed, the cooperation of the first controller (i.e., the upper controller) is required to control the steering range, so as to ensure the steering safety of the vehicle.

In addition, when the steering wheel is steered at a low speed and a large pivot angle, the rotating range of the steering wheel and the aligning force setting output by the steering wheel road feel simulation module need to be considered, and the steering wheel road feel simulation module is limited by software in a mode of setting a dead point. Meanwhile, the corresponding aligning force is gradually increased before reaching the soft dead center of the steering wheel so as to fit the hand feeling of the common automobile steering wheel as much as possible.

Optionally, the third control sub-module comprises:

the request unit is used for sending request information for entering a large-angle steering mode to the first controller when the current vehicle speed is greater than 0 and less than the first preset speed;

the control unit is used for determining the first target corner as a second preset angle corresponding to the current vehicle speed according to the corresponding relation between the vehicle speed and the preset angle when receiving an allowance signal fed back by the first controller according to the request information;

and under the large-angle steering mode, the running speed of the vehicle is less than or equal to a second preset speed, and the second preset speed is less than the first preset speed.

It should be noted that when the current vehicle speed is greater than 0 and less than the first preset speed, that is, under a low-speed condition, the upper controller needs to be requested to enter a large-angle steering mode. And the upper layer controller confirms the surrounding vehicle condition information and road condition information and limits the current vehicle speed before entering a large-angle steering mode. Limiting the current vehicle speed means limiting the current vehicle speed to a certain value, that is, after receiving the request message, the upper controller needs to control the speed to be below a second preset speed, and then sends the permission signal to the steer-by-wire controller 01, so as to ensure the safety of vehicle steering. Wherein, the second preset speed can be obtained by calibration, for example, can be set to 10 km/h. The wide-angle steering operation in response to the driver is permitted after being permitted to enter the wide-angle steering mode. Further, the vehicle speed in the wide-angle steering mode can be set to be constant at a second preset speed, for example, the vehicle speed in the wide-angle steering mode can be set to be constant at 5km/h, so as to achieve a better safety effect.

Optionally, the first controller comprises an advanced driving assistance system, ADAS, controller or a chassis domain controller.

The embodiment of the invention also provides control equipment, which comprises a memory, a processor and a program which is stored on the memory and can be operated on the processor; the processor implements the control method as described above when executing the program.

The embodiment of the invention also provides an automobile which comprises the control device.

While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.