Steering resistance feedback device, steer-by-wire system, steering control method and vehicle

Abstract

The invention relates to the technical field of vehicle driving, in particular to a steering resistance feedback device, a steer-by-wire system, a steering control method and a vehicle, the steering resistance feedback device provided by the embodiment of the invention is applied to the vehicle, and comprises a shell provided with a containing cavity; the magnetorheological fluid is arranged in the accommodating cavity; the coil is arranged on the inner circumferential wall of the containing cavity, and the coil is electrically connected with a power system and an electronic control unit of the vehicle; the rotor rotationally penetrates through the shell and the magnetorheological fluid, and one end of the rotor is coaxially connected with a steering column of the vehicle; the angular displacement sensor is coaxially arranged at the end, away from the steering column, of the rotor, and the angular displacement sensor is electrically connected with the electronic control unit. According to the embodiment of the invention, the steering resistance torque can be simulated and generated instead of a road feeling motor, the energy consumption is reduced, meanwhile, the influence of noise and vibration is reduced, and the driving comfort is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle driving, and particularly to a steering resistance feedback device, a steer-by-wire system, a steering control method, and a vehicle. Background Art

[0002] The steer-by-wire system plays a core role in vehicle driving. It revolutionizes the traditional steering mechanism, enhancing driving convenience and safety. This system transmits the driver's steering intention through electronic signals, eliminating mechanical connections, making the steering more sensitive and direct. This not only improves the vehicle's handling performance but also reduces the driver's physical labor. Especially in complex road conditions and high-speed driving, the steer-by-wire system can provide a more stable and precise steering experience.

[0003] The steer-by-wire system mainly includes key structures such as an angular displacement sensor, a road feel motor, and an electronic control unit (ECU). The angular displacement sensor precisely monitors the driver's operation of the steering wheel, including the rotation angle and speed. This information is converted into electrical signals in real time. The electrical signals are then sent to the ECU, which calculates the appropriate steering angle and force according to the vehicle's driving state and steering requirements, and then controls the road feel motor to perform the steering action. The road feel motor directly acts on the steering mechanism, simulating the feedback torque of the traditional steering system to provide the driver with the necessary driving feel and road feel information.

[0004] However, the road feel motor has some defects during operation. Since it needs to provide a large amount of power to ensure fast and accurate steering response, this results in relatively high energy consumption. In addition, the road feel motor may generate certain noise and vibration during high-speed operation. These adverse factors may be transmitted to the driver's feel and hearing, thus affecting driving comfort and the vehicle's NVH (noise, vibration, and harshness) performance. Summary of the Invention

[0005] The present invention provides a steering resistance feedback device, a steer-by-wire system, a steering control method, and a vehicle. The steering resistance feedback device can replace the road feel motor to simulate and generate a steering resistance torque, reducing energy consumption and at the same time reducing the influence of noise and vibration, thereby enhancing driving comfort.

[0006] In a first aspect, an embodiment of the present invention provides a steering resistance feedback device applied to a vehicle, including: a housing provided with an accommodation cavity; a magnetorheological fluid disposed in the accommodation cavity; a coil disposed on the inner peripheral wall of the accommodation cavity, the coil being electrically connected to the vehicle's power system and an electronic control unit; a rotor rotatably passing through the housing and the magnetorheological fluid, one end of the rotor being coaxially connected to the steering column of the vehicle; and an angular displacement sensor coaxially disposed at one end of the rotor away from the steering column, the angular displacement sensor being electrically connected to the electronic control unit; wherein, the electronic control unit controls the input current of the coil according to the detection signal of the angular displacement sensor to generate a steering resistance torque through the magnetorheological fluid.

[0007] In a possible implementation manner, the accommodation cavity is an annular cavity, and the coil is arranged to surround the inner peripheral wall of the annular cavity to form a closed magnetic field circuit.

[0008] In a possible implementation manner, a radially extending fixed disk is provided on the outer peripheral surface of the rotor, the fixed disk is located in the accommodation cavity and immersed in the magnetorheological fluid, and the fixed disk rotates synchronously with the rotor.

[0009] In a possible implementation manner, the magnetorheological fluid includes a carrier fluid and ferromagnetic particles dispersed in the carrier fluid, wherein: the carrier fluid is silicone oil; the ferromagnetic particles are carbonyl iron powder, the mass percentage of the ferromagnetic particles is 70%-80%, and the particle size of the ferromagnetic particles is 1-100 microns.

[0010] In a possible implementation manner, the coil is wound with enameled wire, and the number of turns is 500-1000 turns; the input current range of the coil is 0-5V, and when the input power of the coil is 30W, the maximum resistance torque generated is 10 Nm.

[0011] In a possible implementation manner, the housing includes an upper housing and a lower housing, and the upper housing and the lower housing are detachably connected by bolts; the materials of the housing and the rotor are both pure iron materials to form a magnetic field conduction path.

[0012] In a possible implementation manner, an insulating layer is provided on the outer surface of the coil, the insulating layer is formed by dip coating with an epoxy resin material, and the thickness of the insulating layer is 0.2-0.5 mm.

[0013] In a possible implementation manner, it further includes: two thrust bearings respectively disposed at both ends of the rotor, each thrust bearing connecting the rotor and the housing; and two seals fixedly disposed between the two thrust bearings and connecting the rotor and the housing, the seals being labyrinth seals.

[0014] In a second aspect, an embodiment of the present invention further provides a steer-by-wire system, including: the above-mentioned steering resistance feedback device; a steering wheel fixedly connected to a steering column; an automatic return-to-center assembly, including: a torque sensor disposed on the steering column for detecting a torque value of the steering column; a stepper motor connected to the steering column, and when the torque value is less than a preset threshold, the stepper motor drives the steering column to return to the center.

[0015] In a possible implementation, it further includes: a wheel steering assembly, including: a steering motor electrically connected to an angular displacement sensor; a steering gear mechanically connected to the steering motor; wherein, the electronic control unit controls the rotation speed and steering angle of the steering motor according to the detection signal of the angular displacement sensor and the vehicle speed signal.

[0016] In a third aspect, an embodiment of the present invention further provides a steering control method applied to the above-mentioned steer-by-wire system, including: obtaining a steering angle signal detected by the angular displacement sensor and a torque signal detected by the torque sensor; determining a target steering resistance torque according to the steering angle signal and the vehicle speed signal; adjusting the input current of the coil according to the target steering resistance torque; when the torque signal is less than a preset threshold, controlling the stepper motor to perform a return-to-center operation.

[0017] In a fourth aspect, an embodiment of the present invention further provides a vehicle, including the above-mentioned steer-by-wire system.

[0018] The steering resistance feedback device, steer-by-wire system, steering control method and vehicle provided by the present invention. The steering resistance feedback device is connected to the steering wheel through the steering column, and the magnetorheological fluid is disposed in the accommodating cavity of the housing so that the steering resistance controllable tactile feedback device forms a magnetic conduction path. When the coil is connected to the input current of the vehicle, the coil generates a closed magnetic field along the magnetic conduction path. The magnitude of the input current can be adjusted through the induction signal of the angular displacement sensor, thereby controlling the intensity of the closed magnetic field. Under this mechanism, the magnetorheological fluid is affected by the closed magnetic field, and its viscosity changes to a certain extent, thereby simulating and generating the required steering resistance torque, giving the driver corresponding road surface feedback, and at the same time, the energy consumption degree of the vehicle can be reduced, and interference factors such as noise and vibration can be avoided; at the same time, the rotor of the device can be connected to the steering wheel through mechanical structures such as the steering column, providing a natural driving experience similar to that of a traditional steering system, thereby improving the manual driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 This is a schematic three-dimensional structure diagram of a steering resistance feedback device provided by the present invention.

[0021] Figure 2 This is a schematic three-dimensional structure diagram of a steer-by-wire system provided by the present invention.

[0022] Figure 3 This is a flowchart of a steering control method provided by the present invention.

[0023] Reference numerals: 1. Housing; 11. Accommodation cavity; 12. Upper housing; 13. Lower housing; 14. Bolt; 2. Coil; 3. Rotor; 31. Fixed disk; 4. Angular displacement sensor; 5. Thrust bearing; 6. Seal; 7. Steering wheel; 8. Steering column; 9. Automatic return-to-center assembly; 91. Torque sensor; 92. Stepper motor; 100. Steering motor; 200. Steering gear; 300. Steering wheel. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0025] The following Figure 1 describes a steering resistance feedback device provided by an embodiment of the present invention, which is applied to a vehicle and includes a housing 1, magnetorheological fluid, a coil 2, a rotor 3 and an angular displacement sensor 4, wherein: The housing 1 is provided with an accommodation cavity 11.

[0026] The magnetorheological fluid is arranged in the accommodation cavity 11.

[0027] The coil 2 is arranged on the inner peripheral wall of the accommodation cavity 11, and the coil 2 is electrically connected to the power system and the electronic control unit of the vehicle.

[0028] The rotor 3 rotatably penetrates through the housing 1 and the magnetorheological fluid, and one end of the rotor 3 is coaxially connected to the steering column 8 of the vehicle.

[0029] The angular displacement sensor 4 is coaxially arranged at one end of the rotor 3 away from the steering column 8, and the angular displacement sensor 4 is electrically connected to the electronic control unit.

[0030] Among them, the electronic control unit controls the input current of the coil 2 according to the detection signal of the angular displacement sensor 4 to generate a steering resistance torque through the magnetorheological fluid.

[0031] In the embodiment of the present invention, the steering resistance feedback device is connected to the steering wheel through the steering column 8, and the magnetorheological fluid is arranged in the accommodation cavity 11 of the housing 1 to enable the steering resistance controllable tactile feedback device to form a magnetic conduction path. When the coil 2 is connected to the input current of the vehicle, the coil 2 generates a closed magnetic field along the magnetic conduction path. The magnitude of the input current can be adjusted through the induction signal of the angular displacement sensor 4, so as to control the intensity of the closed magnetic field. Under this mechanism, the magnetorheological fluid is affected by the closed magnetic field, and its viscosity changes to a certain extent, so as to simulate and generate the required steering resistance torque, giving the driver corresponding road surface feedback. At the same time, the energy consumption of the vehicle can be reduced, and interference factors such as noise and vibration can be avoided; at the same time, the rotor 3 of the device can be connected to the steering wheel through mechanical structures such as the steering column 8 to provide a natural driving experience similar to that of a traditional steering system, thereby improving the manual driving experience.

[0032] Specifically, the housing 1 includes an upper housing 12 and a lower housing 13. The upper housing 12 and the lower housing 13 are detachably connected by locking members such as bolts or snap structures, or can be integrally connected by a welding process, which is not limited herein; the upper housing 12 and the lower housing 13 enclose a circular accommodation cavity 11, and the accommodation cavity 11 is used to accommodate and place the magnetorheological fluid, so that the steering resistance controllable tactile feedback device can form a magnetic conduction path; an annular coil 2 is arranged on the inner peripheral wall of the accommodation cavity 11. The annular coil 2 can be arranged in close contact with the inner peripheral wall of the accommodation cavity 11 and surround the inner peripheral wall of the accommodation cavity 11 in multiple turns. In this way, when the coil 2 is connected to the current provided by the vehicle's power system, a uniform magnetic field can be generated to make the magnetorheological fluid change uniformly; both the upper housing 12 and the lower housing 13 are provided with a jack, and the rotor 3 can be inserted into and extended out of the accommodation cavity 11 through the two jacks and contact the magnetorheological fluid. By using the viscosity change of the magnetorheological fluid, different steering resistance torques can be simulated to obtain the required tactile feedback (i.e., the road feeling feedback during driving).

[0033] Among them, the rotor 3 and the angular displacement sensor 4 are coaxially arranged. In this way, the change angle detected by the angular displacement sensor 4 is the rotation angle of the rotor 3, thereby improving the detection accuracy.

[0034] In the related art, a steer-by-wire system mainly includes key structures such as an angular displacement sensor 4, a road feel motor, and an electronic control unit (ECU). The road feel motor directly acts on the steering mechanism to simulate the feedback torque of a traditional steering system, providing necessary driving feel and road feel information for the driver. During operation, the road feel motor needs to provide relatively large power to ensure fast and accurate steering response, which results in relatively high energy consumption. In addition, the road feel motor may generate certain noise and vibration during high-speed operation, and these adverse factors may be transmitted to the driver's feel and hearing, thus affecting driving comfort and the NVH (noise, vibration, and harshness) performance of the vehicle.

[0035] In the embodiment of the present invention, the steering resistance feedback device accommodates magnetorheological fluid through the accommodation cavity 11 in the housing 1, and uses the coil 2 to generate a magnetic field to control the viscosity change of the magnetorheological fluid, thereby achieving precise control of the steering resistance. In an actual driving scenario, when the vehicle is driving at a high speed, the system can increase the current of the coil 2 to increase the viscosity of the magnetorheological fluid and generate a larger steering resistance to prevent the steering wheel from being too light; when the vehicle is driving at a low speed, reducing the current of the coil 2 can reduce the steering resistance, facilitating the driver's operation. At the same time, since the magnetorheological fluid is used to replace the traditional road feel motor, the energy consumption can be effectively reduced. The traditional road feel motor requires 30 - 50 W of power during continuous operation, while this device only requires less than 10 W of power to achieve the same effect. Among them, the power range of this device is 0 - 30 W. In addition, the response time of the magnetorheological fluid can reach the millisecond level, enabling faster road feel feedback. The cooperation between the angular displacement sensor 4 and the electronic control unit enables the entire system to control the steering resistance in real time and precisely, providing a better driving experience.

[0036] In some embodiments, the accommodation cavity 11 is an annular cavity, and the coil 2 is arranged to surround the inner peripheral wall of the annular cavity, forming a closed magnetic field circuit.

[0037] In the embodiment of the present invention, by designing the accommodation cavity 11 as an annular structure and arranging the coil 2 to surround the inner peripheral wall of the annular cavity, a complete closed magnetic field circuit is formed. This design has significant advantages in practical applications: First, the annular structure makes the magnetic field distribution more uniform, avoiding sudden changes in steering resistance caused by uneven local magnetic field intensity; second, the closed magnetic field circuit improves the magnetic field utilization efficiency, and compared with an open magnetic field structure, the energy consumption can be reduced by 15 - 20%; in addition, the annular structure also facilitates the uniform distribution of the magnetorheological fluid, reducing the generation of dead zones. During high-speed steering, this structure can ensure the smooth change of the steering resistance, avoiding the chattering phenomenon that may occur in traditional mechanical structures.

[0038] In some embodiments, a radially extending fixed disk 31 is provided on the outer peripheral surface of the rotor 3. The fixed disk 31 is located within the accommodation chamber 11 and immersed in the magnetorheological fluid, and the fixed disk 31 rotates synchronously with the rotor 3.

[0039] In the embodiments of the present invention, a fixed rotating disk is provided on the outer surface of the rotor 3. The fixed rotating disk is fixedly connected to the rotor 3 to achieve synchronous rotation with the rotor 3. The fixed rotating disk is located within the accommodation chamber 11 and contacts the magnetorheological fluid. In this way, the contact area between the rotor 3 and the magnetorheological fluid can be increased. When the rotor 3 rotates along its central axis, it drives the angular displacement sensor 4 to rotate synchronously. The angular displacement sensor 4 can detect the rotation angle and generate an electrical signal. The electrical signal is processed and analyzed by the electronic control unit (ECU) of the vehicle assembly, and finally determines the magnitude of the current input to the input coil 2, thereby obtaining an appropriate steering resistance torque. It can be understood that the current value of the input current of the coil 2 can be obtained by comprehensively analyzing the detection signals of different sensors of the vehicle. For example, the vehicle is equipped with sensors for detecting vehicle speed and road surface roughness, etc. The electronic control unit (ECU) of the vehicle comprehensively analyzes these detection signals to control the specific input value of the input current.

[0040] Specifically, the fixed disk 31 is immersed in the magnetorheological fluid and rotates synchronously with the rotor 3, greatly increasing the contact area with the magnetorheological fluid. In practical applications, this design makes the generation of steering resistance more sufficient and uniform. For example, when the driver quickly steers, the large-area contact of the fixed disk 31 can provide sufficient damping force to prevent the steering wheel from rotating too fast; when fine adjustment of the vehicle direction is required, the fixed disk 31 can provide delicate force feedback. Experimental data shows that compared with the structure without the fixed disk 31, this design can increase the effective contact area by about 200%, significantly improving the control accuracy of the steering torque.

[0041] In some embodiments, the magnetorheological fluid includes a carrier fluid and ferromagnetic particles dispersed in the carrier fluid, wherein: the carrier fluid is silicone oil; the ferromagnetic particles are carbonyl iron powder, and the mass percentage of the ferromagnetic particles is 70%-80%, and the particle size of the ferromagnetic particles is 1-100 microns.

[0042] In the embodiments of the present invention, the specific composition of the magnetorheological fluid is optimized. Selecting silicone oil as the carrier fluid has good temperature stability and can maintain stable performance in the range of -40°C to 120°C, which ensures the reliable operation of the device under different climatic conditions. The selection of carbonyl iron powder is also carefully designed: a mass percentage of 70%-80% ensures sufficient magnetic response intensity, and a particle size of 1-100 microns avoids particle sedimentation while ensuring responsiveness. This ratio shows excellent performance in practical applications: the response time can reach 3-5 milliseconds, much faster than traditional mechanical structures; at the same time, the ferromagnetic particles are well dispersed, and the service life can reach more than 100,000 kilometers.

[0043] In some embodiments, the coil 2 is wound with enameled wire, and the number of turns is 500-1000 turns; the input current range of the coil 2 is 0-5V, and when the input power of the coil 2 is 30W, the maximum resistance torque generated is 10 Nm.

[0044] In the embodiments of the present invention, the precise setting of the parameters of the coil 2 plays a crucial role in the system performance. The design of 500-1000 turns can generate a magnetic field with sufficient intensity in practical applications without causing excessive electromagnetic interference. The input current range of 0-5V matches the vehicle power supply system, facilitating integration and control. When the input power is 30W, a maximum resistance torque of 10 Nm can be generated, which is consistent with the actual driving requirements: it can provide sufficient steering resistance without making the steering wheel too heavy. The optimized design of these parameters enables the system to provide an appropriate steering experience under different working conditions.

[0045] Specifically, the resistance torque range of this device is 0-10 Nm.

[0046] In some embodiments, the housing 1 includes an upper housing 12 and a lower housing 13, and the upper housing 12 and the lower housing 13 are detachably connected by bolts; the materials of the housing 1 and the rotor 3 are both pure iron materials, forming a magnetic field conduction path.

[0047] In the embodiments of the present invention, the housing 1 is designed with a detachable upper and lower housing 13, which is convenient for assembly and maintenance. In actual use, if it is necessary to replace the magnetorheological fluid or repair internal parts, the upper housing 12 can be easily disassembled for operation. Selecting pure iron material as the material of the housing 1 and the rotor 3 forms an ideal magnetic field conduction path with a magnetic permeability as high as 4000-8000, which ensures the full utilization of the magnetic field intensity. At the same time, the pure iron material has good mechanical strength and wear resistance, and can withstand long-term mechanical stress and wear.

[0048] Specifically, the materials of the housing 1 and the rotor 3 are both made of pure iron, so that the upper housing 12, the lower housing 13 and the magnetorheological fluid form a complete magnetic conduction path around the coil 2 in the longitudinal section. When current is input into the coil 2, a closed magnetic field is generated in the magnetic conduction path, thus ensuring the uniformity of the change of the magnetorheological fluid. At the same time, since the rotor 3 is made of pure iron, it can effectively conduct and concentrate the magnetic field. When the rotor 3 is in the magnetorheological fluid, it can enhance the effect of the magnetic field, making the magnetic particles in the magnetorheological fluid form a chain structure more quickly and effectively, thereby enhancing the magnetorheological effect.

[0049] Optionally, the housing 1 can be integrally connected by a welding process, which is not limited herein.

[0050] In some embodiments, an insulating layer is provided on the outer surface of the coil 2. The insulating layer is formed by a dip coating process using an epoxy resin material, and the thickness of the insulating layer is 0.2 - 0.5 mm.

[0051] In the embodiments of the present invention, the design of the insulating layer on the outer surface of the coil 2 is crucial for the reliability of the system. The insulating layer formed by a dip coating process using an epoxy resin material has excellent insulating properties and mechanical strength. The thickness design of 0.2 - 0.5 mm can ensure the insulating effect without significantly affecting the magnetic field strength. This insulating design can effectively prevent the coil 2 from directly contacting the magnetorheological fluid, extend the service life, and also has good heat dissipation performance to avoid overheating of the coil 2. Experiments show that the insulating layer can withstand a breakdown voltage of more than 3000 V, ensuring the electrical safety of the system.

[0052] In some embodiments, it further includes: two thrust bearings 5, respectively provided at both ends of the rotor 3, and each thrust bearing 5 is connected to the rotor 3 and the housing 1; and two seals 6, fixedly provided between the two thrust bearings 5 and connected to the rotor 3 and the housing 1, and the seal 6 is a labyrinth seal ring.

[0053] Specifically, a thrust bearing 5 is fixed to the upper housing 12 and located above the jack, and a thrust bearing 5 is fixed to the lower housing 13 and located below the jack. The two ends of the rotor 3 are respectively inserted with a thrust bearing 5, so that each thrust bearing 5 is connected to the rotor 3 and the housing 1. In this way, when the rotor 3 rotates, axial movement can be avoided, thereby ensuring the measurement accuracy of the angular displacement sensor 4 and the connection stability with the steering column 8 of the vehicle. To prevent the magnetorheological fluid from leaking out of the jacks of the upper housing 12 and the lower housing 13, the steering resistance controllable tactile feedback device further includes two seals 6, and each seal 6 is respectively arranged at the jack, so that the two seals 6 are both fixedly arranged between the two thrust bearings 5 and connected to the rotor 3 and the housing 1. To facilitate the coil 2 to access current, the upper housing 12 of the housing 1 is provided with an outlet hole, and a part of the structure of the coil 2 passes through the outlet hole and is exposed outside the housing 1, so that the coil 2 can be electrically connected to the vehicle's power system; at the same time, the outlet hole is sealed to prevent the magnetorheological fluid from leaking out or external impurities from entering the magnetorheological fluid.

[0054] In the embodiment of the present invention, the design of the thrust bearing 5 and the seal 6 constitutes a complete sealing system. The two thrust bearings 5 can not only bear the axial force, but also ensure the coaxiality of the rotor 3 and reduce the vibration caused by eccentricity. The selection of the labyrinth seal has unique advantages: good sealing effect can be achieved without contact, greatly reducing the friction loss; at the same time, the labyrinth structure can effectively prevent the magnetorheological fluid from leaking and external pollutants from entering. The reliability of this sealing system has been verified by 1 million cycle tests, and the leakage rate is controlled below 0.01 ml / day.

[0055] As Figure 2 shown, the embodiment of the present invention also provides a steer-by-wire system, including: the above-mentioned steering resistance feedback device; a steering wheel 7 fixedly connected to the steering column 8; an automatic return-to-center assembly 9, including: a torque sensor 91 arranged on the steering column 8 for detecting the torque value of the steering column 8; a stepper motor 92 connected to the steering column 8, when the torque value is less than a preset threshold, the stepper motor 92 drives the steering column 8 to return to the center.

[0056] In the embodiment of the present invention, the overall design of the steer-by-wire system realizes the intelligent control of steering. The addition of the automatic return-to-center assembly 9 enables the system to have an active safety function: when it is detected that the steering wheel 7 has no manual operation (the torque value is less than the preset threshold), the stepper motor 92 will automatically return the steering wheel to the center, which is especially important when driving at high speed and can prevent the vehicle from deviating from the lane. In practical applications, this function can effectively reduce driving fatigue and improve driving safety.

[0057] Specifically, the system includes the steering resistance feedback device, steering wheel 7, steering column 8, and automatic return-to-center assembly 9 in the above embodiments. The steering wheel 7 is fixedly connected to the steering column 8 through a spline. The steering column 8, rotor 3, and angular displacement sensor 4 are strictly coaxially arranged, and the axis deviation is controlled within 0.02 mm. Such a precise coaxiality requirement can ensure the smooth operation of the system. The automatic return-to-center assembly 9 includes a torque sensor 91 and a stepper motor 92. The torque sensor 91 is a strain gauge sensor with a measuring range of ±20 Nm and an accuracy of 0.1 Nm. The stepper motor 92 is a two-phase hybrid stepper motor 92 with a step angle of 1.8° and a maximum torque of 5 Nm. When the torque value detected by the torque sensor 91 is less than 0.1 Nm, the system determines that the driver has released the steering wheel. At this time, the stepper motor 92 starts and drives the steering column 8 to perform the return-to-center action.

[0058] In one embodiment, when the driver applies a turning force to the steering wheel 7, the torque sensor 91 can detect the corresponding torque. For example, when the torque is less than 0.1, it can be determined that the driver does not apply a force to the steering wheel or has released the hand. At this time, the stepper motor 92 starts to control the rotation of the steering column 8 to return the steering wheel 7 to the straight-ahead position. When the torque is greater than 0.1, it means that the driver applies a force to the steering wheel, and the stepper motor 92 is turned off, entering the manual driving state. Thus, through the combined action of the torque sensor 91 and the stepper motor 92, the automatic return-to-center function of the steering wheel 7 can be realized.

[0059] In this embodiment, the control strategy of the system specifically includes multiple working stages. In the system startup stage, sensor self-check is first performed to confirm that key components such as the angular displacement sensor 4 and torque sensor 91 are working properly. In the normal driving stage, the system continuously collects signals such as steering angle and vehicle speed, and calculates the required basic steering resistance through a preset algorithm. When the system detects a steering action, it adjusts the input current of the coil 2 in real time according to the steering angular velocity and road conditions, and then changes the viscosity of the magnetorheological fluid to generate an appropriate steering resistance. The system also sets multiple driving modes: in the comfort mode, the steering is light, and the maximum resistance torque is limited to 6 Nm; in the standard mode, moderate feedback is provided, and the maximum resistance torque is 8 Nm; in the sport mode, a heavier feel is provided, and the maximum resistance torque can reach 10 Nm.

[0060] In some embodiments, it further includes: a wheel steering assembly, including: a steering motor 100 electrically connected to the angular displacement sensor 4; a steering gear 200 mechanically connected to the steering motor 100; wherein, the electronic control unit controls the rotation speed and steering angle of the steering motor 100 according to the detection signals of the angular displacement sensor 4 and the vehicle speed signal, and then controls the steering wheel 300.

[0061] In the embodiments of the present invention, the design of the wheel steering assembly improves the functional chain of the entire steering system. The electrical connection between the steering motor 100 and the angular displacement sensor 4 ensures the accurate execution of steering commands. The electronic control unit can adjust the steering ratio in real time according to parameters such as vehicle speed, realizing the function of variable steering ratio. For example, a large steering ratio is adopted at low speeds for easy parking, and a small steering ratio is adopted at high speeds to improve handling stability. This intelligent steering control can make driving easier and safer.

[0062] As Figure 3 shown, the embodiments of the present invention also provide a steering control method, which is applied to the above-mentioned steer-by-wire system and includes: S1. Obtain the steering angle signal detected by the angular displacement sensor 4 and the torque signal detected by the torque sensor 91; S2. Determine the target steering resistance torque according to the steering angle signal and the vehicle speed signal; S3. Adjust the input current of the coil 2 according to the target steering resistance torque; S4. When the torque signal is less than the preset threshold, control the stepper motor 92 to perform a return operation.

[0063] In the embodiments of the present invention, the design of the steering control method realizes the intelligent operation of the system. By obtaining the steering angle signal and the torque signal in real time and combining the vehicle speed information, the system can accurately calculate the required steering resistance torque, enabling the driver to obtain an appropriate steering feel under different working conditions. Especially in complex road conditions, such as cornering and sharp turning, the system can dynamically adjust the steering resistance according to actual needs, ensuring both the flexibility of control and the safety of driving.

[0064] Specifically, the method first collects various signals required for the operation of the system in real time, including the steering angle signal of the angular displacement sensor 4 (sampling frequency 1 kHz), the torque signal of the torque sensor 91 (sampling frequency 500 Hz), and the vehicle speed signal (sampling frequency 100 Hz). The system calculates the steering angular velocity based on these signals, determines the target steering ratio in combination with the current vehicle speed, and then calculates the required steering resistance torque. Under standard working conditions, when the steering angular velocity is less than 100° / s, the system linearly adjusts the steering resistance; when the steering angular velocity is in the range of 100 - 300° / s, the steering resistance is increased in a non-linear manner; when the steering angular velocity exceeds 300° / s, the system quickly increases the steering resistance to prevent the steering wheel from turning sharply. Under special working conditions, the system will adjust the control strategy according to specific situations: for example, reducing the steering resistance during emergency avoidance to improve the response speed, increasing the return torque during high-speed straight driving to improve direction stability, and minimizing the steering resistance during low-speed parking to provide a light operation feeling.

[0065] The embodiments of the present invention also provide a vehicle, including the above-mentioned steer-by-wire system.

[0066] In the embodiments of the present invention, applying the steer-by-wire system to a whole vehicle can comprehensively improve the handling performance and safety of the vehicle. The intelligent features of the system enable the vehicle to adapt to different driving scenarios: providing a light steering feel when driving at low speeds in the city, providing a heavier steering feedback when driving at high speeds, and being able to quickly respond to the driver's steering intention in case of emergency avoidance. At the same time, due to the adoption of magnetorheological fluid technology, the energy consumption of the whole system is low, which can improve the overall energy efficiency of the vehicle.

[0067] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steering resistance feedback device, applied to a vehicle, characterized in that: The steering resistance feedback device comprises: A housing (1), wherein the housing (1) is provided with a receiving cavity (11); A magnetorheological fluid is arranged in the accommodating chamber (11); A coil (2) is arranged on the inner peripheral wall of the accommodating cavity (11), and the coil (2) is electrically connected to the power system and the electronic control unit of the vehicle; a rotor (3) which rotates and penetrates the housing (1) and the magnetorheological fluid, one end of the rotor (3) being coaxially connected to a steering column (8) of the vehicle; and An angular displacement sensor (4) is coaxially arranged at an end of the rotor (3) away from the steering column (8), the angular displacement sensor (4) being electrically connected to the electronic control unit; The electronic control unit controls the input current of the coil (2) according to the detection signal of the angular displacement sensor (4), so as to generate a steering resistance torque through the magnetorheological fluid.

2. The steering resistance feedback device according to claim 1, characterized in that: The accommodating cavity (11) is an annular cavity, and the coil (2) is disposed along the inner peripheral wall of the annular cavity to form a closed magnetic field loop.

3. The steering resistance feedback device according to claim 2, characterized in that: A radially extending fixed disk (31) is provided on the outer peripheral surface of the rotor (3); the fixed disk (31) is located in the accommodating cavity (11) and immersed in the magnetorheological fluid; the fixed disk (31) rotates synchronously with the rotor (3).

4. The steering resistance feedback device according to claim 1, characterized in that: The magnetorheological fluid comprises a carrier liquid and ferromagnetic particles dispersed in the carrier liquid, wherein: The carrier liquid is silicone oil; The ferromagnetic particles are carbonyl iron powder, the mass percentage of the ferromagnetic particles is 70%-80%, and the particle size of the ferromagnetic particles is 1-100 microns.

5. The steering resistance feedback device according to claim 1, characterized in that: The coil (2) is wound with enameled wire, with the number of turns being 500-1000 turns; The input current range of the coil (2) is 0-5V, and when the input power of the coil (2) is 30W, the maximum resistance torque generated is 10Nm.

6. The steering resistance feedback device according to any one of claims 1 to 5, characterized in that: The housing (1) comprises an upper housing (12) and a lower housing (13), wherein the upper housing (12) and the lower housing (13) are detachably connected via bolts; The material of the housing (1) and the material of the rotor (3) are both pure iron, forming a magnetic field conduction path.

7. The steering resistance feedback device according to any one of claims 1 to 5, characterized in that: An insulating layer is provided on the outer surface of the coil (2); the insulating layer is formed by using epoxy resin material through a dipping process; the thickness of the insulating layer is 0.2-0.5 mm.

8. The steering resistance feedback device according to any one of claims 1 to 5, characterized in that: Also includes: Two thrust bearings (5) are respectively arranged at two ends of the rotor (3), and each thrust bearing (5) is connected to the rotor (3) and the housing (1); Two sealing members (6) are fixedly arranged between the two thrust bearings (5) and connect the rotor (3) and the housing (1); the sealing members (6) are labyrinth seal rings.

9. A steer-by-wire system, characterized in that: include: The steering resistance feedback device according to any one of claims 1 to 8; A steering wheel (7) fixedly connected to the steering column (8); The automatic return component (9) comprises: A torque sensor (91), arranged on the steering column (8), and used to detect a torque value of the steering column (8); A stepper motor (92) is connected to the steering column (8), and when the torque value is less than a preset threshold, the stepper motor (92) drives the steering column (8) to return to the center.

10. The steer-by-wire system according to claim 9, characterized in that: Also includes: Wheel steering assembly, comprising: A steering motor (100), electrically connected to the angular displacement sensor (4); A steering gear (200) mechanically connected to the steering motor (100); The electronic control unit controls the rotation speed and steering angle of the steering motor (100) according to the detection signal of the angular displacement sensor (4) and the vehicle speed signal.

11. A steering control method, characterized in that: The steer-by-wire system according to claim 9 or 10 comprises: Acquiring a steering angle signal detected by the angular displacement sensor (4) and a torque signal detected by the torque sensor (91); determining a target steering resistance torque according to the steering angle signal and the vehicle speed signal; According to the target steering resistance torque, adjusting the input current of the coil (2); When the torque signal is less than a preset threshold, the stepping motor (92) is controlled to perform a return operation.

12. A vehicle, characterized in that: comprising a steering resistance feedback device as claimed in any one of claims 1 to 8; Or, comprising a steer-by-wire system as claimed in claim 9 or 10; Alternatively, the steering control method as claimed in claim 11 is adopted.

Images