Automobile steering control method and automobile steering control device

Abstract

The invention discloses an automobile steering control method which comprises the following steps: S1, acquiring a torque applied to a steering wheel by a driver through a torque sensor, acquiring a steering angle of the steering wheel through an angle sensor, and acquiring a current driving mode, speed, acceleration and body posture of an automobile at the same time; s2, determining an ideal relative rotation angle of left and right steering wheels based on the driving mode, the vehicle speed, the accelerated speed and the vehicle body posture, and calculating a target correction telescopic length of a telescopic rod for adjusting steering geometry according to the ideal relative rotation angle; and S3, the telescopic rod is controlled to stretch out and draw back according to the target correction telescopic length, so that the actual relative rotation angle of the left steering wheel and the right steering wheel is dynamically adjusted, and the actual toe-in angle approaches the target toe-in angle. The technical problems that in the prior art, a steering system cannot adaptively adjust steering geometry according to the dynamic state of a vehicle, auxiliary control activation logic is incomplete, and steering response is delayed due to the fact that the interior of a steering gear lacks a lubricating state monitoring and active maintenance mechanism are solved.

Description

Technical Field

[0001] This invention relates to the field of steering equipment technology, and more specifically to a vehicle steering control method and a vehicle steering control device. Background Technology

[0002] In modern automotive steering systems, especially electric power steering and steer-by-wire systems, the gears, racks, or worm gears inside the steering gear are in a state of high-frequency reciprocating motion for a long time. Their performance and lifespan are highly dependent on good lubrication conditions. Traditional steering gears usually use a one-time sealed grease filling method, and the lubricating medium cannot be replenished or replaced during the entire life of the vehicle. As the usage time increases, the grease is prone to failure due to high temperature oxidation, mechanical shearing, or impurity intrusion, resulting in increased friction of moving parts, slow response, and in severe cases, even jamming or abnormal noise, directly affecting steering safety. Especially under high load conditions, the steering motor and transmission mechanism will generate significant heat. Since steering gears are mostly closed metal shell structures with limited heat dissipation paths, the continuous rise in internal temperature not only accelerates the deterioration of the lubricating medium, but also causes thermal expansion of materials and changes in clearance, further deteriorating transmission accuracy and system stability. However, the existing technology lacks real-time monitoring means for the lubrication status inside the steering gear, and there is no active lubrication and synergistic cooling mechanism, making it difficult to guarantee the reliability of the system under high temperature and high load conditions.

[0003] Although some high-end models have attempted to introduce oil bath lubrication or circulating lubrication systems, their complex structure and high cost, and their use in commercial vehicles or racing cars, make them difficult to popularize in mass-produced passenger cars. Meanwhile, in intelligent driving and human-machine co-driving scenarios, the steering system needs to be assisted by the vehicle controller when the driver's hands are lightly gripping the steering wheel. At this time, if the steering gear responds abnormally due to poor lubrication or excessive temperature rise, it will seriously affect the accuracy and safety of assisted steering. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a vehicle steering control method and a vehicle steering control device, which solves the technical problems in the prior art where the steering system cannot adaptively adjust the steering geometry according to the vehicle's dynamic state, the auxiliary control activation logic is imperfect, and the steering gear lacks a lubrication status monitoring and active maintenance mechanism, resulting in sluggish steering response.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a vehicle steering control method, which includes the following steps when the driver's hands are lightly gripping the steering wheel and the vehicle controller acts as an auxiliary system to control the vehicle:

[0007] S1. The torque applied to the steering wheel by the driver is obtained through the torque sensor, and the steering wheel angle is obtained through the angle sensor. At the same time, the current driving mode, vehicle speed, acceleration and vehicle attitude are also obtained.

[0008] S2. Based on the driving mode, vehicle speed, acceleration and vehicle posture, determine the ideal relative turning angle of the left and right steering wheels, and calculate the target corrected telescopic length of the telescopic rod used to adjust the steering geometry accordingly.

[0009] S3. Control the telescopic rod to extend and retract according to the target modified telescopic length, so as to dynamically adjust the actual relative turning angle of the left and right steering wheels, so that the actual toe angle approaches the target toe angle;

[0010] S4. When all of the following conditions are met, the vehicle controller activates the steering assist function and outputs an enable signal: the steering system is in normal condition; the vehicle speed is greater than the preset minimum value and less than the preset maximum value; the steering wheel torque is less than the preset torque threshold; the steering angle sensor is in normal working condition; if any condition is not met, the vehicle controller outputs a fault message.

[0011] S5. Obtain the actual position of the steering gear, and calculate the target steering motor torque by combining the steering wheel vibration coefficient, steering wheel torque and vehicle speed; after performing lubrication treatment and safety verification on the steering gear, output the target steering motor torque to drive the steering actuator.

[0012] In some embodiments, step S1 further includes: calculating the steering wheel angular velocity at each sampling time based on the steering wheel angle; if the steering angular velocity shows a monotonically increasing trend within a preset time period, then determining that the vehicle is in a state of increasing steering angle.

[0013] In some embodiments, when determining the ideal relative turning angle in step S2, the method further includes: calculating the first ideal relative turning angle of the left and right steering wheels using a vehicle dynamics model based on vehicle chassis parameters, current vehicle speed, acceleration, and vehicle body posture.

[0014] In some embodiments, when the driving mode is straight-line cruise mode, in step S2, the target toe angle is set to zero toe, and the second corrected telescopic length of the telescopic rod is calculated accordingly to control the telescopic rod to retract to achieve a zero toe state for the left and right steering wheels.

[0015] In some embodiments, based on the vehicle's centripetal acceleration and the difference in speed between the four wheels, combined with a preset steering trend mapping relationship, it is determined whether the vehicle has an understeer trend; if so, the ideal relative steering angle is compensated and corrected in step S2.

[0016] In some embodiments, a steering rod is rotatably connected to the lower end of the steering wheel, a steering gear is provided at the lower end of the steering rod, and a lubrication mechanism is provided inside the steering gear.

[0017] In some embodiments, the steering gear includes a housing, the end of the steering rod passes through the housing and is connected to the first gear, the outer periphery of the first gear meshes with the second gear, a pull rod is also provided inside the housing, and the pull rod has a tooth groove on the side facing the second gear, and the lubrication mechanism includes a liquid reservoir installed on the outside of the housing, and a monitoring end is also provided inside the liquid reservoir.

[0018] In some embodiments, the monitoring end includes a low liquid level sensor and a high liquid level sensor, which are installed from bottom to top inside the liquid storage tank and are used to monitor the liquid level height.

[0019] In some embodiments, a spray end communicating with the liquid storage tank is further provided inside the housing. The spray end includes a spray pipe and a liquid guide pipe. The spray pipe is disposed inside the housing and faces the meshing point of the first gear and the second gear. Multiple spray heads are provided on the spray pipe. The spray pipe communicates with the inside of the liquid storage tank through the liquid guide pipe, and a liquid pump is installed on the liquid guide pipe. A liquid supply pipeline is provided at the upper end of the liquid storage tank.

[0020] In some embodiments, the system further includes a vehicle controller, which is communicatively connected to the torque sensor, steering angle sensor, vehicle speed sensor, acceleration sensor, and the drive unit of the telescopic rod.

[0021] Compared with existing technologies, the present invention provides a vehicle steering control method that calculates the ideal relative steering angle of the left and right steering wheels in real time based on driving mode, vehicle speed, acceleration, and vehicle posture, and drives the telescopic rod to precisely adjust its extension length. This allows for dynamic adjustment of the toe angle or Ackermann geometry. For example, during high-speed straight-line cruising, it automatically approaches zero toe to reduce rolling resistance and tire wear; during cornering, it optimizes the difference in steering angle between the inner and outer wheels according to centripetal requirements, effectively suppressing understeer or oversteer, and significantly improving the vehicle's trajectory tracking accuracy and lateral stability. By simultaneously monitoring steering wheel torque, vehicle speed, system status, and sensor health, it constructs multi-dimensional activation conditions to avoid accidental activation of assisted steering when vehicle speed is too high, the driver intervenes forcefully, or the system malfunctions. This mechanism prevents the system from blindly taking over in dangerous conditions and ensures timely assistance when the driver's attention is diverted but the vehicle remains controllable, achieving safe and smooth human-machine control. In the handover process, when outputting the target steering motor torque, not only traditional factors are considered, but also the steering wheel vibration coefficient is introduced as a correction factor. This makes the power assist characteristics more in line with actual driving intentions and road condition changes, improving the balance between low-speed lightness and high-speed stability, and enhancing driving comfort and confidence. Before each steering command is output, the steering gear is lubricated and safety checked, which can effectively prevent steering abnormalities caused by dry friction, lubrication failure, or mechanical jamming. Especially under high load or high temperature conditions, this mechanism can significantly extend the life of key components such as gears and racks, reduce the failure rate, and provide a solid hardware reliability foundation for intelligent assisted steering functions. It also provides data and architectural support for the subsequent expansion of advanced functions. The parameters collected in this solution, such as acceleration, vehicle attitude, and four-wheel speed, not only serve the current steering geometry adjustment, but can also be used to further judge the dynamic trend of the vehicle, and combine with the lubricant temperature or flow rate to achieve integrated coordination of lubrication, cooling, and control. Attached Figure Description

[0022] Figure 1 This is a perspective view of the automobile steering control device provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the interior of the housing of the automotive steering control device provided in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the internal lubrication mechanism of the automobile steering control device provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the monitoring end assembly of the automobile steering control device provided in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1. Steering wheel; 2. Steering lever; 3. Steering gear; 31. Housing; 32. First gear; 33. Second gear; 34. Tie rod; 341. Gear groove; 4. Lubrication mechanism; 41. Liquid reservoir; 42. Monitoring end; 421. Low liquid level sensor; 422. High liquid level sensor; 43. Spray end; 431. Spray pipe; 4311. Spray head; 432. Liquid guide pipe; 4321. Liquid pump; 44. Liquid supply line. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a car steering control device according to an embodiment of the present invention. A car steering control device includes:

[0029] S1. The torque applied by the driver to the steering wheel 1 is obtained through the torque sensor, and the steering angle of the steering wheel 1 is obtained through the angle sensor. At the same time, the current driving mode, vehicle speed, acceleration and vehicle posture of the vehicle are also obtained.

[0030] S2. Based on driving mode, vehicle speed, acceleration and vehicle posture, determine the ideal relative turning angle of the left and right steering wheels, and calculate the target corrected telescopic length of the telescopic rod used to adjust the steering geometry accordingly.

[0031] S3. Control the telescopic rod to extend and retract according to the target modified telescopic length, so as to dynamically adjust the actual relative turning angle of the left and right steering wheels, so that the actual toe angle is close to the target toe angle;

[0032] S4. When all of the following conditions are met, the vehicle controller activates the steering assist function and outputs an enable signal: the steering system is in normal condition; the vehicle speed is greater than the preset minimum value and less than the preset maximum value; the steering wheel torque is less than the preset torque threshold; the steering angle sensor is in normal working condition; if any condition is not met, the vehicle controller outputs a fault message.

[0033] S5. Obtain the actual position of the steering gear 3, and calculate the target steering motor torque by combining the steering wheel 1 vibration coefficient, steering wheel 1 torque and vehicle speed; and after performing lubrication treatment and safety verification on the steering gear 3, output the target steering motor torque to drive the steering actuator.

[0034] In this embodiment, the ideal relative steering angles of the left and right steering wheels are calculated in real time based on driving mode, vehicle speed, acceleration, and vehicle posture. The telescopic rod is then precisely adjusted to dynamically change its extension length, allowing for dynamic adjustment of the toe angle or Ackermann geometry. For example, during high-speed straight-line cruising, the toe angle automatically approaches zero to reduce rolling resistance and tire wear. During cornering, the difference in steering angle between the inner and outer wheels is optimized based on centripetal requirements, effectively suppressing understeer or oversteer and significantly improving the vehicle's trajectory tracking accuracy and lateral stability. By simultaneously monitoring steering wheel torque, vehicle speed, system status, and sensor health, multi-dimensional activation conditions are constructed to prevent accidental activation of the assisted steering when vehicle speed is too high, the driver intervenes forcefully, or the system malfunctions. This mechanism prevents the system from blindly taking over in dangerous conditions and ensures timely assistance when the driver's attention is diverted but the vehicle remains controllable, achieving a safe and smooth handover of human-machine control. This results in the output target steering... When adjusting the motor torque, in addition to traditional factors, the steering wheel vibration coefficient is introduced as a correction factor to make the power assist characteristics more in line with actual driving intentions and road condition changes. This improves the balance between low-speed lightness and high-speed stability, enhancing driving comfort and confidence. Before each steering command output, the steering gear 3 undergoes lubrication treatment and safety verification, which can effectively prevent steering abnormalities caused by dry friction, lubrication failure, or mechanical jamming. Especially under high load or high temperature conditions, this mechanism can significantly extend the life of key components such as gears and racks, reduce the failure rate, and provide a solid hardware reliability foundation for intelligent assisted steering functions. It also provides data and architectural support for subsequent expansion of advanced functions. The parameters collected in this solution, such as acceleration, vehicle posture, and four-wheel speed, not only serve the current steering geometry adjustment but can also be used to further judge the dynamic trend of the vehicle and achieve integrated coordination of lubrication, cooling, and control in combination with lubricant temperature or flow.

[0035] In one embodiment, to improve the steering efficiency of the device, the steering angular velocity of the steering wheel 1 is calculated at each sampling time based on the steering wheel 1 angle. If the steering angular velocity shows a monotonically increasing trend within a preset time period, it is determined that the vehicle is in a state of increasing steering angle. When determining the ideal relative steering angle, the method further includes calculating the first ideal relative steering angle of the left and right steering wheels based on the vehicle chassis parameters, current vehicle speed, acceleration, and vehicle posture through a vehicle dynamics model. When the driving mode is straight-line cruise mode, the target toe angle is set to zero toe, and the second corrected extension length of the telescopic rod is calculated accordingly to control the telescopic rod to retract to achieve a zero toe state for the left and right steering wheels. Based on the vehicle's centripetal acceleration and the difference in speed between the four wheels, combined with a preset steering trend mapping relationship, it is determined whether the vehicle has an understeer trend. If so, the ideal relative steering angle is compensated and corrected.

[0036] In this embodiment, by calculating the steering angular velocity of steering wheel 1 at each sampling moment and determining whether it shows a monotonically increasing trend within a preset time period, it can effectively identify that the driver is actively increasing steering input. Compared to relying solely on the instantaneous value of the current steering angle or torque, this method can capture the evolution direction of steering intention earlier, providing a time lead for the subsequent dynamic adjustment of the ideal relative steering angle, avoiding control lag, and making the vehicle response more in line with the driver's expectations. When determining the ideal relative steering angle, the vehicle chassis parameters, such as wheelbase, track width, kingpin offset, current vehicle speed, longitudinal / lateral acceleration, and vehicle attitude, such as roll angle and pitch angle, are comprehensively considered. Through a vehicle dynamics model, such as a bicycle model or a more advanced multi-degree-of-freedom model, the first ideal relative steering angle of the left and right steering wheels is calculated. This method ensures that the steering geometry always conforms to the theoretically optimal Ackermann relationship of the vehicle in the current motion state, effectively reducing tire sideslip, reducing rolling resistance, and improving trajectory tracking accuracy and stability in curves. When the vehicle is identified as being in a straight-line cruise mode, such as cruise control or lane centering assist, the method can effectively reduce tire sideslip, reduce rolling resistance, and improve trajectory tracking accuracy and stability in curves. When there is no significant steering input, the system actively sets the target toe angle to zero and calculates the second corrected extension length of the telescopic rod accordingly. This drives the actuator to make the left and right steering wheels parallel. The zero toe state can minimize tire slippage and unnecessary friction during straight-line driving, which not only reduces fuel consumption and tire noise, but also significantly extends tire life. At the same time, it improves straight-line stability and ride comfort at high speeds. By integrating centripetal acceleration, the system reflects the actual turning intensity and the difference in four-wheel speed, reflecting the tire slip state. Combined with preset steering trend mapping relationships, such as understeer criteria built based on empirical data or machine learning models, the system can identify the potential risk of understeer before the vehicle deviates significantly from the expected trajectory. Once the trend is confirmed, the system actively compensates and corrects the originally calculated ideal relative turning angle, such as appropriately increasing the outer wheel turning angle or decreasing the inner wheel turning angle, to enhance the vehicle's steering response and help the driver complete cornering or obstacle avoidance operations more smoothly, effectively preventing the risk of loss of control. This is especially valuable for safety in wet and slippery road conditions or emergency lane change scenarios.

[0037] In one embodiment, please refer to Figure 1 - Figure 4To improve the working efficiency of the lubrication mechanism 4, a steering rod 2 is rotatably connected to the lower end of the steering wheel 1. A steering gear 3 is provided at the lower end of the steering rod 2, and the lubrication mechanism 4 is provided inside the steering gear 3. The steering gear 3 includes a housing 31, and the end of the steering rod 2 passes through the housing 31 and is connected to a first gear 32. A second gear 33 meshes with the outer periphery of the first gear 32. A pull rod 34 is also provided inside the housing 31, and a tooth groove 341 is provided on the side of the pull rod 34 facing the second gear 33. The lubrication mechanism 4 includes a liquid storage tank 41 installed on the outside of the housing 31, and a monitoring end 42 is also provided inside the liquid storage tank 41. The monitoring end 42 includes a low liquid level sensor 421 and a high liquid level sensor 422. 22 is installed from bottom to top inside the liquid storage tank 41 and is used to monitor the liquid level. The housing 31 is also provided with a spray end 43 that communicates with the liquid storage tank 41. The spray end 43 includes a spray pipe 431 and a liquid guide pipe 432. The spray pipe 431 is located inside the housing 31 and faces the meshing point of the first gear 32 and the second gear 33. Multiple spray heads 4311 are opened on the spray pipe 431. The spray pipe 431 communicates with the inside of the liquid storage tank 41 through the liquid guide pipe 432. A liquid pump 4321 is installed on the liquid guide pipe 432. A liquid supply pipeline 44 is provided at the upper end of the liquid storage tank 41. The system also includes a vehicle controller. The vehicle controller is communicatively connected to the torque sensor, angle sensor, vehicle speed sensor, acceleration sensor and the drive unit of the telescopic rod.

[0038] In this embodiment, the spray pipe 431 is precisely arranged inside the housing 31, directly opposite the meshing area of ​​the first gear 32 and the second gear 33, and is equipped with multiple spray heads 4311. This allows the lubricant to be sprayed directly and evenly onto the high-load friction pair surface in atomized or jet form. Compared to traditional overall oil immersion or grease sealing lubrication methods, this avoids wasting lubricating medium, ensures that the limited lubricant acts efficiently on the most wear-prone parts, and significantly reduces the friction coefficient and wear rate during gear meshing. Driven by the pump 4321, the lubricant circulates through the guide pipe 432 and is sprayed onto the lubricating surface. While lubricating, the lubricant continuously removes heat generated by friction in the gear meshing area. Due to the high specific heat capacity and fluidity of the lubricant, this process forms a mechanism of simultaneous lubrication and cooling, effectively controlling the internal temperature rise of the steering gear 3 and preventing material softening, grease carbonization, or clearance changes caused by high temperatures. Especially under high heat load conditions such as low speed, large steering angle, and frequent steering, it can significantly improve the system's thermal stability and long-term operational reliability. The low-level sensor 421 and high-level sensor 422 installed in the reservoir 41 can monitor the lubricant level in real time. When the level is lower than the lower threshold, the system can notify the driver. The system issues a low lubricant warning when the operator or vehicle controller issues a warning. When the lubricant level is reached via the supply line 44, the system automatically stops adding lubricant to prevent overflow. This enables visualized management and on-demand maintenance of lubricant resources. The reservoir 41 is installed on the outside of the housing 31 for easy level observation and replenishment. The spray pipe 431 and the guide pipe 432 are integrated inside the housing 31, without affecting the original sealing structure of the steering gear 3. The entire system achieves functional upgrades without significantly increasing the size of the steering gear 3, is highly adaptable to the compact space of the passenger vehicle's front compartment, and possesses excellent engineering feasibility and mass production compatibility. The vehicle controller not only receives signals such as torque, steering angle, vehicle speed, and acceleration for steering control decisions, but also dynamically adjusts the start / stop or flow rate of the liquid pump 4321 according to the vehicle's operating status, such as continuous steering duration, motor load, and ambient temperature, to achieve on-demand lubrication. For example, it reduces the lubrication frequency to save energy during long-term high-speed cruising, and enhances lubrication and cooling intensity in aggressive driving or high-temperature environments. In addition, it performs lubrication treatment and safety verification before executing steering commands to ensure that each steering action is completed in the best mechanical condition, preventing control failure caused by dry friction or jamming from the source.

[0039] To better understand this invention, the following is combined with... Figures 1 to 4 The technical solution of the present invention will be described in detail below:

[0040] S1. The torque applied by the driver to the steering wheel 1 is obtained in real time through the torque sensor, the steering angle of the steering wheel 1 is obtained through the angle sensor, and the current driving mode, vehicle speed, longitudinal / lateral acceleration and body posture, including roll angle and pitch angle, are obtained from the vehicle communication network, such as CAN bus. The four wheel speed signals are collected for subsequent dynamic trend analysis.

[0041] S2. Based on the steering wheel 1 angle sequence, calculate the steering wheel 1 steering angular velocity at each sampling time. If the steering angular velocity shows a monotonically increasing trend within a preset time period, it is determined that the vehicle is in a state of increasing steering angle. The centripetal acceleration and the four-wheel speed difference are fused together, and the preset steering trend mapping relationship is combined with the preset steering trend mapping relationship, such as based on an empirical threshold or machine learning model, to determine whether the vehicle has an understeer trend.

[0042] S3. Based on the vehicle chassis parameters, such as wheelbase, track width, kingpin offset, current vehicle speed, acceleration, and vehicle attitude, calculate the first ideal relative steering angle of the left and right steering wheels using the vehicle dynamics model. If understeering is determined in S2, actively compensate and correct the first ideal relative steering angle to obtain the final target ideal relative steering angle. Furthermore, if the current driving mode is straight-line cruise mode, such as cruise control being activated and no significant steering input, the target toe angle is forcibly set to zero toe, and the corresponding second corrected telescopic length of the telescopic rod is recalculated accordingly.

[0043] S4. Based on the target ideal relative angle obtained in S3, or the angle corresponding to zero toe, calculate the target corrected telescopic length of the telescopic rod used to adjust the geometry of the steering tie rod 34, control the drive unit of the telescopic rod, such as an electric push rod or a hydraulic cylinder, to extend and retract according to the target length, and dynamically adjust the actual relative angle of the left and right steering wheels so that the actual toe angle approaches the target toe angle.

[0044] S5. The vehicle controller verifies in real time whether all of the following conditions are met simultaneously: the steering system is fault-free, the system status is normal, the vehicle speed is greater than the preset minimum value, such as 5 km / h, and less than the preset maximum value, such as 120 km / h, the steering wheel torque is less than the preset torque threshold, indicating the "hands loose" state, and the steering angle sensor is working normally. If all conditions are met, the steering assist function is activated and a function enable signal is output. If any condition is not met, activation is prohibited and a fault prompt is output.

[0045] S6. Before outputting the steering command, start the pump 4321 to deliver the lubricant in the reservoir 41 to the spray pipe 431 via the guide pipe 432, and spray the lubricant onto the meshing area of ​​the first gear 32 and the second gear 33 through multiple spray nozzles 4311; simultaneously, read the signals from the low level sensor 421 and the high level sensor 422 to confirm that the lubricant level is sufficient. If the level is too low, record a fault code and restrict high-load steering operations. After lubrication, perform a safety check on the position of the steering gear 3, the motor status, and the mechanical connections to ensure there is no jamming or abnormal resistance. The monitoring terminal 42 is installed at... Inside the reservoir 41, a monitoring unit 42 is used to monitor the lubricant level in real time, ensuring that the lubrication system is always in an effective operating range. The monitoring unit 42 includes a low level sensor 421 and a high level sensor 422, which are fixed vertically from bottom to top on the inner wall of the reservoir 41. The low level sensor 421 is located near the bottom of the reservoir 41, corresponding to the minimum safe level at which the lubrication system can maintain basic spraying function. When the lubricant level is below this position, the sensor outputs a "low level" electrical signal to the vehicle controller. The high level sensor 422 is located at the top of the reservoir 41, corresponding to the maximum allowable filling level.When lubricating fluid is replenished to the required level via supply line 44, the sensor outputs a "high level" signal, prompting a stop to the replenishment process to prevent overflow or air lock. The vehicle controller determines the current fluid level range based on the combined status of the two sensors. If only the low level sensor 421 is triggered, indicating a low fluid level, a lubricating fluid shortage warning is issued, and high-load steering operations are restricted. If neither the high nor low level sensor is triggered, indicating a normal fluid level, the lubrication system is allowed to operate as needed. If the high level sensor 422 is triggered, indicating a full fluid level, the external replenishment channel is closed. This dual-sensor system avoids the risk of misjudgment associated with single-point detection, achieving a reliable fluid level range identification and maintenance reminder mechanism. When the vehicle controller determines that a steering action is about to be performed, such as S5... Before the signal is valid and the S7 torque output is entered, or when a high-wear risk condition such as continuous steering or high-temperature operation is detected, a start command is sent to the lubrication mechanism 4. Upon receiving the command, the pump 4321 installed on the liquid guide pipe 432 starts, drawing the lubricant from the reservoir 41 through the liquid guide pipe 432. One end of the liquid guide pipe 432 is connected to the bottom of the reservoir 41, and the other end is connected to the spray pipe 431 inside the housing 31. The spray pipe 431 is arranged horizontally or in an arc shape inside the housing 31, directly facing the meshing area of ​​the first gear 32 and the second gear 33, which is the critical part with the most intense friction and the highest temperature rise. Multiple spray heads 4311 are provided on the spray pipe 431, distributed at a certain angle, to ensure the lubricant... The lubricant evenly covers the gear tooth surface and meshing gap in the form of atomized or fine jet. While forming an oil film to reduce friction, the lubricant, due to its high specific heat capacity and fluidity, continuously absorbs and carries away the heat generated by mechanical friction in the meshing area, achieving the dual effect of lubrication and cooling simultaneously. In some embodiments, the bottom of the housing 31 is provided with a return chamber or guide channel, so that the used lubricant can be preliminarily filtered through a filter screen and then returned to the liquid storage tank 41, forming a semi-closed circulation system to further improve the utilization rate of lubricant. If it is a one-time lubrication, the return structure is omitted. After the spraying continues for a preset time, such as 0.5–2 seconds, the liquid pump 4321 is turned off, the spraying stops, the system records this lubrication event, and updates the lubricant consumption estimate. The value is used for long-term health status assessment. The lubrication mechanism 4 does not operate independently, but is deeply integrated into the vehicle control logic. The vehicle controller can dynamically adjust the spraying time or pumping pressure according to parameters such as vehicle speed, steering frequency, motor current, and ambient temperature to achieve an intelligent lubrication strategy of less spraying under light load and more spraying under heavy load. If a low liquid level alarm is detected during the lubrication process, safety is prioritized and the output of large-angle or high-speed steering commands is restricted. The lubrication action and the steering motor torque output are strictly synchronized in time to ensure that each steering operation is performed in the best mechanical condition, fundamentally preventing steering failure caused by dry friction, jamming, or thermal deformation. It is particularly suitable for intelligent assisted steering and steer-by-wire scenarios with high reliability requirements.

[0046] S7. Obtain the actual current position of steering gear 3, and combine it with the vibration coefficient of steering wheel 1 to reflect road excitation or micro-operation, steering wheel 1 torque and vehicle speed, and calculate the target steering motor torque; under the premise that the enable signal of S5 is valid and the verification of S6 is passed, output the target torque to the steering motor to drive the steering actuator to complete the precise steering action. At the same time, the vehicle controller can dynamically adjust the subsequent lubrication frequency according to the current working conditions, such as the continuous steering duration and motor temperature, to achieve integrated coordinated operation of lubrication, cooling and control.

[0047] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A vehicle steering control method, wherein when the driver's hands are lightly gripping the steering wheel and the vehicle controller acts as an auxiliary system to control the vehicle, the method comprises the following steps, characterized in that: S1. The torque applied to the steering wheel by the driver is obtained through the torque sensor, and the steering wheel angle is obtained through the angle sensor. At the same time, the current driving mode, vehicle speed, acceleration and vehicle attitude are also obtained. S2. Based on the driving mode, vehicle speed, acceleration and vehicle posture, determine the ideal relative turning angle of the left and right steering wheels, and calculate the target corrected telescopic length of the telescopic rod used to adjust the steering geometry accordingly. S3. Control the telescopic rod to extend and retract according to the target modified telescopic length, so as to dynamically adjust the actual relative turning angle of the left and right steering wheels, so that the actual toe angle approaches the target toe angle; S4. When all of the following conditions are met, the vehicle controller activates the steering assist function and outputs an enable signal, and the steering system is in normal condition: the vehicle speed is greater than the preset minimum value and less than the preset maximum value; the steering wheel torque is less than the preset torque threshold; and the steering angle sensor is working normally. If any condition is not met, the vehicle controller will output a fault message; S5. Obtain the actual position of the steering gear, and calculate the target steering motor torque by combining the steering wheel vibration coefficient, steering wheel torque and vehicle speed; After performing lubrication and safety checks on the steering gear, the target steering motor torque is output to drive the steering actuator.

2. The vehicle steering control method according to claim 1, characterized in that: Step S1 also includes: calculating the steering wheel angular velocity at each sampling time based on the steering wheel angle; if the steering angular velocity shows a monotonically increasing trend within a preset time period, then it is determined that the vehicle is in a state of increasing steering angle.

3. The vehicle steering control method according to claim 1, characterized in that: In step S2, when determining the ideal relative turning angle, the process further includes: calculating the first ideal relative turning angle of the left and right steering wheels using a vehicle dynamics model based on the vehicle chassis parameters, current vehicle speed, acceleration, and vehicle posture.

4. The vehicle steering control method according to claim 1, characterized in that: When the driving mode is straight cruise mode, in step S2, the target toe angle is set to zero toe, and the second corrected telescopic length of the telescopic rod is calculated accordingly to control the telescopic rod to retract until the left and right steering wheels achieve a zero toe state.

5. The vehicle steering control method according to claim 1, characterized in that: Based on the vehicle's centripetal acceleration and the difference in speed between the four wheels, combined with a preset steering trend mapping relationship, it is determined whether the vehicle has an understeer tendency. If it exists, the ideal relative rotation angle is compensated and corrected in step S2.

6. A vehicle steering control device, applicable to the vehicle steering control method as described in any one of claims 1-5, characterized in that: The lower end of the steering wheel is rotatably connected to a steering rod, the lower end of the steering rod is provided with a steering gear, and the steering gear is provided with a lubrication mechanism.

7. A vehicle steering control device according to claim 6, characterized in that: The steering gear includes a housing, the end of the steering rod passes through the housing and is connected to a first gear, a second gear meshes with the outer periphery of the first gear, a pull rod is also provided inside the housing, and the pull rod has a tooth groove on the side facing the second gear, and the lubrication mechanism includes a liquid storage tank installed on the outside of the housing, and a monitoring end is also provided inside the liquid storage tank.

8. A vehicle steering control device according to claim 7, characterized in that: The monitoring terminal includes a low liquid level sensor and a high liquid level sensor, which are installed from bottom to top inside the liquid storage tank and are used to monitor the liquid level height.

9. A vehicle steering control device according to claim 8, characterized in that: The housing is also provided with a spray end that communicates with the liquid storage tank. The spray end includes a spray pipe and a liquid guide pipe. The spray pipe is located inside the housing and faces the meshing point of the first gear and the second gear. Multiple spray heads are provided on the spray pipe. The spray pipe communicates with the inside of the liquid storage tank through the liquid guide pipe, and a liquid pump is installed on the liquid guide pipe. A liquid supply pipeline is provided at the upper end of the liquid storage tank.

10. The vehicle steering control device according to claim 6, characterized in that, It also includes a vehicle controller, which is communicatively connected to the torque sensor, steering angle sensor, vehicle speed sensor, acceleration sensor and the drive unit of the telescopic rod, and is used to execute the control logic as described in any one of claims 1 to 5.

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