Rack end protection method, device, storage medium and vehicle

Abstract

The application provides a rack end protection method and device, a storage medium and a vehicle, and belongs to the technical field of vehicles. The method comprises the following steps: acquiring a rotation speed value and a rotation angle value of a steering wheel in a current direction; determining a rack end protection angle range based on the rotation speed value and a steering limit angle of the steering wheel in the current direction; determining a boost current limit value corresponding to the rotation angle value based on the rotation angle value and the rack end protection angle range; in the case where the boost current limit value is greater than a target boost current, outputting the target boost current as a final boost current; otherwise, outputting the boost current limit value as the final boost current. The rack end protection angle range can be matched based on the rotation speed value and the steering limit angle of the steering wheel in the current direction, and the rack end is protected more flexibly, so that the applicability is strong, and the problem that the rack end protection functions of the same vehicle and different vehicles of the same vehicle type are inconsistent is effectively solved.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method, apparatus, storage medium, and vehicle for protecting the end of a rack. Background Technology

[0002] EPS (Electric Power Steering) systems apply the driving force of an electric power steering motor to the vehicle's rack-and-pinion steering gear via a transmission mechanism as an auxiliary force. This causes the rack to move left and right, thus rotating the wheels and completing the vehicle's steering action. Therefore, EPS electric power steering is ultimately achieved through the left and right movement of the rack. The rack-and-pinion steering gear has a housing, within which the rack is housed. Both ends of the rack pass through the housing and are connected to inner ball joint rods at their ends. When the steering wheel is turned to its limit, the rack moves left or right within the housing, and the inner ball joint rods at the rack's ends strike the housing.

[0003] If the impact force between the inner ball joint tie rod and the housing is too great, it can easily damage the power steering assembly, cause driver discomfort due to noise, and result in a sudden increase in steering wheel resistance torque, leading to poor steering feel. To prevent such incidents, a rack end protection function is generally integrated into the EPS control system. This function reduces the impact force between the tie rod and the housing by decreasing the power steering motor's assist current when the rack end approaches the housing.

[0004] Current rack end protection strategies only select the power steering current limit value based on pre-set rack end protection start and end angles and steering wheel speed. This cannot adapt to all vehicles. Generally, different vehicles of the same model will have slight differences in the left and right limit angles of steering wheel rotation during assembly, use, and maintenance. Furthermore, even within the same vehicle, the steering limit angles of the left and right sides of the steering wheel will differ, leading to inconsistencies in the performance of rack end protection functions between the same vehicle and different vehicles of the same model. If the rack end protection end angle is set too small, while the actual limit angle is large, it will activate prematurely, preventing the steering wheel from reaching its true limit position. Conversely, if the rack end protection end angle is set too large, while the actual limit angle is small, the current limit value at the end angle will not be reached, resulting in a large current output at the limit angle, ultimately causing the motor to enter overheat protection mode. Summary of the Invention

[0005] This application provides a rack end protection method, device, storage medium, and vehicle to solve the problem of inconsistent rack end protection function performance between the same vehicle of the same model and different vehicles in existing rack end protection strategies.

[0006] To solve the above problems, this application adopts the following technical solution:

[0007] In a first aspect, embodiments of this application provide a method for protecting the end of a rack, the method comprising:

[0008] Get the steering wheel's rotation speed and angle in the current direction;

[0009] Based on the rotational speed value and the steering wheel's steering limit angle in the current direction, the rack end protection angle range is determined; the rack end protection angle range is a closed interval composed of the rack end protection start angle and the rack end protection end angle.

[0010] Based on the rotation angle value and the rack end protection angle range, determine the assist current limit value corresponding to the rotation angle value;

[0011] If the assist current limit value is greater than the target assist current, the target assist current is output as the final assist current; otherwise, the assist current limit value is output as the final assist current.

[0012] In one embodiment of this application, the step of determining the rack end protection angle range based on the rotational speed value and the steering wheel's steering limit angle in the current direction includes:

[0013] Determine the fixed difference between the starting angle and the fixed difference between the ending angle corresponding to the rotational speed value; different rotational speed values ​​correspond to different fixed differences between the starting angle and the ending angle.

[0014] Based on the fixed difference between the steering limit angle and the starting angle, the starting angle for rack end protection in the current direction is determined; and based on the fixed difference between the steering limit angle and the ending angle, the ending angle for rack end protection in the current direction is determined.

[0015] The range of rack end protection angles is determined based on the rack end protection start angle and the rack end protection end angle.

[0016] In one embodiment of this application, the step of determining the assist current limit value corresponding to the rotation angle value based on the rotation angle value and the rack end protection angle range includes:

[0017] When the rotation angle value does not enter the protection angle range of the rack end, the assist current limit value is maintained at the rated current value of the assist motor;

[0018] After the angle value enters the protection angle range of the rack end, the assist current limit value decreases from the rated current value to the minimum assist current limit value at a fixed slope, and when the angle value is greater than the rack end protection termination angle, the assist current limit value remains at the minimum assist current limit value.

[0019] In one embodiment of this application, the method further includes:

[0020] When the vehicle meets the learning conditions for steering limit angle, the original left steering limit angle and right steering limit angle of the steering wheel are updated according to the preset steering limit angle self-learning strategy.

[0021] Based on the updated left turn limit angle, update the original rack end protection angle range in the left turn direction; based on the updated right turn limit angle, update the original rack end protection angle range in the right turn direction.

[0022] In one embodiment of this application, the steps of updating the original rack end protection angle range in the left-turn direction based on the updated left-turn limit angle and updating the original rack end protection angle range in the right-turn direction based on the updated right-turn limit angle include:

[0023] Determine the first difference between the original left turn limit angle and the updated left turn limit angle, and the second difference between the original right turn limit angle and the updated right turn limit angle;

[0024] Based on the first difference, update the original rack end protection angle range in the left turn direction; based on the second difference, update the original rack end protection angle range in the right turn direction.

[0025] In one embodiment of this application, the steps of updating the original rack end protection angle range in the left-turn direction based on the first difference and updating the original rack end protection angle range in the right-turn direction based on the second difference include:

[0026] Add the first difference to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the left turn direction, respectively, to obtain the updated rack end protection angle range in the left turn direction.

[0027] The second difference is added to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the right turn direction to obtain the updated rack end protection angle range in the right turn direction.

[0028] In one embodiment of this application, after updating the left and right steering limit angles of the steering wheel according to a preset steering limit angle self-learning strategy when the vehicle meets the steering limit angle learning conditions, the method further includes:

[0029] Once it is confirmed that the left and right steering limit angles of the steering wheel have been successfully updated, the updated left and right steering limit angles will be sent to the backend server.

[0030] If it is determined that the left and right steering wheel limit angles have failed to be updated, a fault code is generated and sent to the background server.

[0031] Secondly, based on the same inventive concept, embodiments of this application provide a rack end protection device, the device comprising:

[0032] The parameter acquisition module is used to obtain the steering wheel's rotation speed and angle values ​​in the current direction;

[0033] The first determining module is used to determine the rack end protection angle range based on the rotation speed value and the steering wheel's steering limit angle in the current direction; the rack end protection angle range is a closed interval composed of the rack end protection start angle and the rack end protection end angle;

[0034] The second determining module is used to determine the assist current limit value corresponding to the rotation angle value based on the rotation angle value and the rack end protection angle range;

[0035] The current output module is used to output the target assist current as the final assist current when the assist current limit value is greater than the target assist current; otherwise, it outputs the assist current limit value as the final assist current.

[0036] In one embodiment of this application, the first determining module includes:

[0037] The fixed difference determination submodule is used to determine the fixed difference between the starting angle and the ending angle corresponding to the rotational speed value; different rotational speed values ​​correspond to different fixed differences between the starting angle and the ending angle.

[0038] An angle determination submodule is used to determine the starting angle of rack end protection in the current direction based on the fixed difference between the steering limit angle and the starting angle; and to determine the ending angle of rack end protection in the current direction based on the fixed difference between the steering limit angle and the ending angle.

[0039] The range determination submodule is used to determine the range of the rack end protection angle based on the rack end protection start angle and the rack end protection end angle.

[0040] In one embodiment of this application, the second determining module includes:

[0041] The first maintenance submodule is used to maintain the assist current limit value at the rated current value of the assist motor when the rotation angle value does not enter the protection angle range of the rack end.

[0042] The second maintenance submodule is used to, after the angle value enters the rack end protection angle range, reduce the assist current limit value from the rated current value to the minimum assist current limit value at a fixed slope, and maintain the assist current limit value at the minimum assist current limit value when the angle value is greater than the rack end protection termination angle.

[0043] In one embodiment of this application, the rack end protection device further includes:

[0044] The limit angle update module is used to update the original left and right steering limit angles of the steering wheel according to a preset steering limit angle self-learning strategy when the vehicle meets the steering limit angle learning conditions.

[0045] The range update module is used to update the original rack end protection angle range in the left turn direction based on the first difference; and to update the original rack end protection angle range in the right turn direction based on the second difference.

[0046] In one embodiment of this application, the range update module includes:

[0047] The difference determination submodule is used to determine the first difference between the original left steering limit angle and the updated left steering limit angle, and the second difference between the original right steering limit angle and the updated right steering limit angle.

[0048] The range update submodule is used to update the original rack end protection angle range in the left turn direction based on the first difference; and to update the original rack end protection angle range in the right turn direction based on the second difference.

[0049] In one embodiment of this application, the range update submodule includes:

[0050] The first updating unit is used to add the first difference to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the left turn direction, so as to obtain the updated rack end protection angle range in the left turn direction.

[0051] The second updating unit is used to add the second difference to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the right turn direction, so as to obtain the updated rack end protection angle range in the right turn direction.

[0052] In one embodiment of this application, the rack end protection device further includes:

[0053] The first sending module is used to send the updated left and right steering limit angles to the background server when it is determined that the left steering limit angle and right steering limit angle of the steering wheel have been successfully updated.

[0054] The second sending module is used to generate a fault code and send the fault code to the background server if it is determined that the update of the left steering limit angle and the right steering limit angle of the steering wheel has failed.

[0055] Thirdly, based on the same inventive concept, embodiments of this application provide a storage medium storing machine-executable instructions, which, when executed by a processor, implement the rack end protection method proposed in the first aspect of this application.

[0056] Fourthly, based on the same inventive concept, embodiments of this application provide a vehicle including a processor and a memory. The memory stores machine-executable instructions that can be executed by the processor, and the processor executes the machine-executable instructions to implement the rack end protection method proposed in the first aspect of this application.

[0057] Compared with the prior art, this application has the following advantages:

[0058] This application provides a rack end protection method that, by acquiring the steering wheel's rotational speed and angle in the current direction, determines the rack end protection angle range based on the rotational speed and the steering wheel's steering limit angle in the current direction. Then, based on the angle value and the rack end protection angle range, it determines the corresponding power assist current limit value. Finally, if the power assist current limit value is greater than the target power assist current, the target power assist current is output as the final power assist current; otherwise, the power assist current limit value is output as the final power assist current. This application, in addition to the rotational speed value, also sets the rack end protection angle range based on the steering wheel's steering limit angle. This allows for matching a suitable rack end protection angle range when the steering wheel's steering limit angle changes, thus providing more flexible rack end protection. It has strong applicability and solves the problem of inconsistent rack end protection performance between the same vehicle and different vehicles of the same model. It also effectively avoids the problems of the power assist motor quickly entering overheat protection mode due to an excessively small rack end protection termination angle setting (leading to the steering wheel not reaching its left or right limit positions) and an excessively large rack end protection termination angle setting (leading to the power assist motor quickly entering overheat protection mode). Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a flowchart of the steps of a rack end protection method in one embodiment of this application.

[0061] Figure 2 This is a schematic diagram of the assist current limiting curve in one embodiment of this application.

[0062] Figure 3 This is a schematic diagram of the functional modules of a rack end protection device according to an embodiment of this application. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] It should be noted that in related technologies, the corresponding power assist current limit value is usually selected based on the preset rack end protection start angle and rack end protection end angle and the steering wheel speed. Specifically, when the steering wheel speed is greater than the rack end protection start angle, it enters the rack end protection angle range, and at this time the power assist current of the power assist motor will be limited.

[0065] The inventors of this application have discovered that the aforementioned rack end protection strategy exhibits inconsistent performance in practical applications between the same vehicle of the same model and different vehicles. Research and analysis have revealed that even vehicles of the same model will experience slight differences in the steering wheel's left and right steering limit angles during assembly, use, and maintenance. Furthermore, even within the same vehicle, the steering limit angles of the left and right sides of the steering wheel will differ to some extent. Since the existing rack end protection strategy does not consider these variations in steering wheel's left and right steering limit angles, the inconsistent performance of the rack end protection function between the same vehicle of the same model and different vehicles may lead to the following two situations:

[0066] Scenario 1: If the rack end protection termination angle is set too small, while the actual steering limit angle is large, the protection will activate prematurely, preventing the steering wheel from reaching its left or right limits. This is because when the steering wheel reaches the rack end protection termination angle, the power steering current is limited to a minimum, and the rack force generated by the driver's hand is insufficient to turn the steering wheel to its end.

[0067] Scenario 2: If the rack end protection termination angle is set too large, while the actual steering limit angle is small, the current limit value corresponding to the rack end protection termination angle will not be reached, and the power steering motor will quickly enter overheat protection mode. This is because when the steering wheel is turned to its extreme end, the torque sensor output value is very high, and the power steering motor's assist current is also very high. Since the assist current is not limited, the power steering motor continuously outputs a large current, forcing it to enter overheat protection mode, which may damage the power steering motor and related mechanical components of the EPS system.

[0068] To address the shortcomings of existing technologies, this application aims to provide a rack end protection method. Based on the rotational speed, the method further sets the rack end protection angle range using the steering wheel's steering limit angle. This allows for matching a suitable rack end protection angle range when the steering wheel's steering limit angle changes, thus providing more flexible rack end protection. It is highly applicable and solves the problem of inconsistent rack end protection performance between the same vehicle and different vehicles of the same model. It also addresses the issues of the steering wheel not being able to reach its left or right limits when the rack end protection termination angle is set too small, and the power steering motor quickly entering overheat protection mode when the rack end protection termination angle is set too large.

[0069] Reference Figure 1 This application illustrates a method for protecting the end of a rack, which may include the following steps:

[0070] S101: Obtain the steering wheel's rotation speed and angle in the current direction.

[0071] It should be noted that the execution subject in this embodiment can be a computing service device with data processing, network communication and program running functions, or an electronic device with the above functions, such as a vehicle computer, an in-vehicle computer, such as an ECU (Electronic Control Unit), a BCM (Body Control Module), a VCU (Vehicle Control Unit), etc. This embodiment will use EPS as the execution subject for description. It should be noted that this embodiment does not impose specific restrictions on the execution subject.

[0072] In this embodiment, the steering angle signal and angular velocity of the steering wheel in the left-turn or right-turn direction can be detected by a steering angle sensor and an angular velocity sensor, respectively. Preferably, a TAS (Torque and Angle Sensor) can be used to detect the rotational speed of the steering wheel in the current direction. It should be noted that the current direction is either the left-turn or right-turn direction starting from the steering wheel's return-to-center position.

[0073] S102: Determine the range of the rack end protection angle based on the rotation speed and the steering wheel's limit angle in the current direction.

[0074] In this embodiment, the rack end protection angle range is a closed interval composed of the rack end protection start angle and the rack end protection end angle. For example, the rack end protection angle range is set to [α, β], where α represents the rack end protection start angle and β represents the rack end protection end angle.

[0075] In this embodiment, for different vehicle models, the EPS stores default steering limit angles for left and right turns, referred to as the left steering limit angle and the right steering limit angle. Therefore, in practical applications, the corresponding rack end protection angle range can be determined based on the engine speed and the steering wheel's steering limit angle in the current direction.

[0076] In this embodiment, considering that the steering wheel may rotate to different left and right limit angles during vehicle assembly, use, and maintenance, the rack end protection angle range can be set to have a fixed angle difference with the steering limit angle. This allows the rack end protection angle range to change with the steering limit angle, thus adaptively adjusting to a suitable rack end protection angle range when the steering limit angle of the steering wheel changes, thereby providing more flexible protection for the rack end.

[0077] It should be noted that the rack end protection angle range is related to the engine speed; different engine speeds correspond to different rack end protection angle ranges. Specifically, the higher the current steering wheel speed, the smaller the rack end protection starting angle α, and the rack end protection ending angle β remains almost constant after reaching a certain value. In this way, the rack end protection function can be quickly activated when the steering wheel is turned quickly, effectively reducing the impact force at the rack end while providing maximum assistance to the driver.

[0078] S103: Based on the rotation angle value and the rack end protection angle range, determine the assist current limit value corresponding to the rotation angle value.

[0079] In this embodiment, by comparing the rotational speed value with the rack end protection angle range, the assist current limit value for each stage can be obtained. Different rotational speed values ​​correspond to different assist current limit values, specifically divided into a pre-protection stage before the rotational angle value enters the rack end protection angle range and a post-protection stage after the rotational angle value enters the rack end protection angle range. Based on the mapping relationship between the rotational angle value and the assist current limit value, an assist current limiting curve can be fitted.

[0080] Reference Figure 2 The diagram illustrates the assist current limiting curve in an embodiment of this application. In the pre-protection phase, when the angle value is less than the rack end protection starting angle α, the assist current limit is maintained at the rated current value of the assist motor. In the post-protection phase, when the angle value is greater than or equal to the rack end protection starting angle α, the assist current limit decreases from the rated current value to the minimum assist current limit at a fixed slope, and when the angle value is greater than the rack end protection termination angle β, the assist current limit is maintained at the minimum assist current limit.

[0081] It should be noted that, Figure 2 This is just an example of the assist current limiting curve for a certain speed value. In reality, since different speed values ​​correspond to different rack end protection angle ranges, different speed values ​​correspond to different assist current limiting curves.

[0082] S104: If the assist current limit value is greater than the target assist current, the output target assist current is the final assist current; otherwise, the output assist current limit value is the final assist current.

[0083] In this embodiment, after obtaining the assist current limit values ​​for each stage, it can be determined whether the assist current limit value is greater than the target assist current. If the assist current limit value is greater than the target assist current, the target assist current is output as the final assist current; otherwise, the assist current limit value is output as the final assist current. It should be noted that the target assist current is the assist current value actually required by the driver for vehicle steering.

[0084] In practice, after obtaining the final assist current, the EPS will calculate the corresponding assist torque and then send a control command containing the assist torque to the assist motor so that the assist motor responds to the control command and drives the steering gear according to the current corresponding to the assist torque to assist the vehicle in steering.

[0085] In this embodiment, by comparing the current assist current limit value corresponding to the current angle value with the target assist current, the final assist current can be limited within the assist current limit value, thereby achieving effective protection for the assist motor and the end of the rack.

[0086] This application embodiment sets the starting angle and ending angle of rack end protection by adjusting the left and right steering limit angles of the steering wheel. This allows for matching a suitable range of rack end protection angles when the steering limit angle of the steering wheel changes, thus providing more flexible protection for the rack end. It has strong applicability and solves the problem of inconsistent rack end protection performance between the same vehicle and different vehicles of the same model. It effectively avoids the problem that the steering wheel cannot be turned to the left or right limit position when the rack end protection ending angle is set too small, and the problem that the power steering motor quickly enters overheat protection when the rack end protection ending angle is set too large.

[0087] In one feasible implementation, S102 may specifically include the following sub-steps:

[0088] S102-1: Determine the fixed difference between the starting angle and the fixed difference between the ending angle corresponding to the rotational speed value.

[0089] In this embodiment, different rotational speed values ​​correspond to different fixed differences in starting angle and fixed differences in ending angle.

[0090] For example, referring to Table 1, a table showing the relationship between the rotational speed value and the fixed difference between the starting angle and the fixed difference between the ending angle is shown.

[0091] Table 1

[0092]

[0093] It should be noted that the fixed difference in starting angle represents the fixed difference between the starting angle of rack end protection and the corresponding steering limit angle, while the fixed difference in ending angle represents the fixed difference between the ending angle of rack end protection and the corresponding steering limit angle. In other words, the following relationship exists between the starting angle α of rack end protection, the ending angle β of rack end protection, the left / right steering limit angle, the fixed difference in starting angle X, and the fixed difference in ending angle Y:

[0094] The starting angle for rack end protection α = Left / Right steering limit angle - Fixed difference in starting angle X;

[0095] The rack end protection termination angle β = left / right steering limit angle - fixed difference in termination angle Y;

[0096] Among them, the fixed difference in the starting angle X is greater than the fixed difference in the ending angle Y.

[0097] S102-2: Based on the fixed difference between the steering limit angle and the starting angle, determine the starting angle of rack end protection in the current direction; and based on the fixed difference between the steering limit angle and the ending angle, determine the ending angle of rack end protection in the current direction.

[0098] For example, referring to Table 2, based on the above relationships, a table showing the correspondence between the rotational speed value and the starting angle and ending angle of rack end protection can be obtained.

[0099] Table 2

[0100]

[0101] It should be noted that the fixed difference in starting angle X and fixed difference in ending angle corresponding to different speed values ​​can be calibrated for different vehicle models, and this implementation method does not impose specific restrictions on them.

[0102] S102-3: Determine the range of rack end protection angles based on the rack end protection start angle and rack end protection end angle.

[0103] In this embodiment, after calculating the rack end protection start angle α and rack end protection termination angle β corresponding to the current rotational speed value, the rack end protection angle range [α, β] corresponding to the current rotational speed value can be obtained.

[0104] In this embodiment, after determining the rack end protection angle range [α, β], the corresponding assist current limit value can be determined based on the rack end protection angle range [α, β]; then, the final assist current is determined based on the assist current limit value. Thus, since the final assist current is obtained based on the real-time steering wheel rotation speed, the assist torque can also be changed in real-time with the steering wheel rotation speed, thereby providing the driver with appropriate assist torque in real-time and improving the driver's driving feel under various vehicle conditions.

[0105] In one feasible implementation, the rack end protection method may further include the following steps:

[0106] S201: When the vehicle meets the learning conditions for steering limit angle, update the original left steering limit angle and right steering limit angle of the steering wheel according to the preset steering limit angle self-learning strategy.

[0107] In this implementation, after repairing or replacing the steering gear or adjusting the four-wheel alignment parameters, the EPS needs to learn the steering limit angles on both sides of the steering wheel. The steering limit angles can be learned by sending signals from a diagnostic tool or through self-learning.

[0108] For example, the preset steering limit angle self-learning strategy can be specifically as follows: The EPS completes the preparation for steering limit angle learning. When the vehicle meets the steering limit angle learning conditions, the EPS sends a learning command through the host computer. The EPS sets the steering limit angle learning flag to not learned and clears the original left and right steering limit angle values ​​so that new left and right steering limit angles can be written after subsequent learning. The EPS controls the steering gear to turn to the left and right limit positions respectively and holds them for a preset time so as to read the accurate left and right steering limit angles. After completing self-learning, the EPS stores the new left and right steering limit angles to update the original left and right steering limit angles of the steering wheel.

[0109] In this embodiment, the updated left steering limit angle and right steering limit angle will be stored in NVM (Non-Volatile Memory), which can be used directly when the vehicle is powered on again, thereby protecting the end of the rack when the steering wheel is turned.

[0110] It should be noted that if the vehicle does not meet the learning conditions for the steering limit angle, or if the update of the left and right steering limit angles of the steering wheel fails, the original left and right steering limit angles of the steering wheel will remain unchanged.

[0111] S202: Based on the updated left turn limit angle, update the original rack end protection angle range in the left turn direction; based on the updated right turn limit angle, update the original rack end protection angle range in the right turn direction.

[0112] In this embodiment, in order to ensure that the rack end can still be effectively protected when the left and right steering limit angles of the vehicle change, and to maintain the consistency of the rack end protection function, the original rack end protection angle range will change with the change of the left and right steering limit angles.

[0113] Specifically, S202 may include the following sub-steps:

[0114] S202-1: Determine the first difference between the original left turn limit angle and the updated left turn limit angle, and the second difference between the original right turn limit angle and the updated right turn limit angle.

[0115] In this embodiment, the original left turning limit angle is denoted as θ1, the original right turning limit angle as θ2, the updated left turning limit angle as θ3, and the updated right turning limit angle as θ4. Then, the first difference △1 = θ3 - θ1; ​​the second difference △2 = θ4 - θ2. The first difference △1 and the second difference △2 can be negative or positive. A negative difference indicates that the turning limit angle in that direction has increased, and a positive difference indicates that the turning limit angle in that direction has decreased.

[0116] S202-2: Based on the first difference, update the original rack end protection angle range in the left turn direction; based on the second difference, update the original rack end protection angle range in the right turn direction.

[0117] In this embodiment, in order to ensure that the starting angle and ending angle of the rack end protection angle range remain unchanged regardless of how the steering limit angle changes, the original rack end protection angle range will change by the same amount based on the first difference or the second difference.

[0118] Specifically, for the rack end protection angle range in the left-turn direction, the first difference △1 is added to the rack end protection start angle α1 and rack end protection end angle β1 corresponding to the original rack end protection angle range [α1, β1] in the left-turn direction, so as to obtain the updated rack end protection angle range [α1+△1, β1+△1] in the left-turn direction; for the rack end protection angle range in the right-turn direction, the second difference △2 is added to the rack end protection start angle α2 and rack end protection end angle β2 corresponding to the original rack end protection angle range [α2, β2] in the right-turn direction, so as to obtain the updated rack end protection angle range [α2+△2, β2+△2].

[0119] In one feasible implementation, after S201, the rack end protection method may further include the following steps:

[0120] S301: If the left and right steering wheel limit angles are successfully updated, send the updated left and right steering wheel limit angles to the backend server.

[0121] In this embodiment, EPS will monitor the update progress to determine whether the update of the left and right steering wheel limit angles is complete. After confirming that the update of the left and right steering wheel limit angles is successful, in addition to storing the updated left and right steering wheel limit angles in NVM, a CAN message containing the updated left and right steering wheel limit angles will be generated and sent to the CAN bus so that the vehicle's vehicle networking system can upload the data to the backend server. This allows the after-sales service center to monitor the actual left and right steering wheel limit angles of the vehicle, and to combine the performance parameters of the vehicle's steering mechanism and user operating habits with the data to provide feedback to the product design center to support product design improvements.

[0122] Specifically, the product design center can infer the wear of mechanical parts, such as bushings and housings, based on the changes in the left and right steering limit angles of the steering gear. It can also monitor data such as the hand force, angle, and duration of the steering wheel at the end of the turn based on the driver's parking habits, and infer the most comfortable level of power assist for the driver under different operating conditions, so as to adjust the power assist current limit value.

[0123] S302: If the update of the left and right steering wheel limit angles fails, a fault code is generated and sent to the background server.

[0124] In this implementation, if the EPS detects a failure to update the left and right steering wheel limit angles during the update process, it will generate a corresponding fault code. Different fault codes indicate different causes of the fault. Based on the fault code, the EPS will generate a fault message containing that fault code and send it to the CAN bus. This allows the vehicle's vehicle networking system to upload the fault message to the backend server. The after-sales service center can parse the fault message to obtain the corresponding fault code. By analyzing the fault code, the center can determine whether the EPS has correctly calibrated the left and right steering wheel limit angles, promptly analyze and address the cause of the fault, and prevent the delivery of uncalibrated vehicles to users, which could lead to functional abnormalities and customer complaints.

[0125] Secondly, based on the same inventive concept, and referring to... Figure 3 This application provides a rack end protection device 300, which includes:

[0126] The parameter acquisition module 301 is used to acquire the speed and angle values ​​of the steering wheel in the current direction.

[0127] The first determining module 302 is used to determine the rack end protection angle range based on the rotational speed value and the steering wheel's steering limit angle in the current direction. The rack end protection angle range is a closed interval consisting of the rack end protection start angle and the rack end protection end angle.

[0128] The second determining module 303 is used to determine the assist current limit value corresponding to the rotation angle value based on the rotation angle value and the protection angle range of the rack end.

[0129] The current output module 304 is used to output the target assist current as the final assist current when the assist current limit value is greater than the target assist current. Otherwise, it outputs the assist current limit value as the final assist current.

[0130] In one embodiment of this application, the first determining module 302 includes:

[0131] The fixed difference determination submodule is used to determine the fixed difference between the starting angle and the ending angle corresponding to a given speed value. Different speed values ​​correspond to different fixed differences between the starting angle and the ending angle.

[0132] The angle determination submodule is used to determine the starting angle of rack end protection in the current direction based on a fixed difference between the steering limit angle and the starting angle. It also determines the ending angle of rack end protection in the current direction based on a fixed difference between the steering limit angle and the ending angle.

[0133] The range determination submodule is used to determine the range of rack end protection angles based on the rack end protection start angle and rack end protection end angle.

[0134] In one embodiment of this application, the second determining module 303 includes:

[0135] The first maintenance submodule is used to maintain the assist current limit value at the rated current value of the assist motor when the rotation angle value does not enter the rack end protection angle range.

[0136] The second maintenance submodule is used to reduce the assist current limit value from the rated current value to the minimum assist current limit value at a fixed slope after the rotation angle value enters the rack end protection angle range, and to maintain the assist current limit value at the minimum assist current limit value when the rotation angle value is greater than the rack end protection termination angle.

[0137] In one embodiment of this application, the rack end protection device 300 further includes:

[0138] The limit angle update module is used to update the original left and right steering wheel limit angles according to a preset steering limit angle self-learning strategy when the vehicle meets the steering limit angle learning conditions.

[0139] The range update module is used to update the original rack end protection angle range in the left-turn direction based on the first difference, and to update the original rack end protection angle range in the right-turn direction based on the second difference.

[0140] In one embodiment of this application, the range update module includes:

[0141] The difference determination submodule is used to determine the first difference between the original left steering limit angle and the updated left steering limit angle, and the second difference between the original right steering limit angle and the updated right steering limit angle.

[0142] The range update submodule is used to update the original rack end protection angle range in the left-turn direction based on the first difference. It also updates the original rack end protection angle range in the right-turn direction based on the second difference.

[0143] In one embodiment of this application, the range update submodule includes:

[0144] The first updating unit is used to add a first difference to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the left turn direction, so as to obtain the updated rack end protection angle range in the left turn direction.

[0145] The second updating unit is used to add a second difference to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the right turn direction, so as to obtain the updated rack end protection angle range in the right turn direction.

[0146] In one embodiment of this application, the rack end protection device 300 further includes:

[0147] The first sending module is used to send the updated left and right steering limit angles to the backend server when it is determined that the left and right steering limit angles of the steering wheel have been successfully updated.

[0148] The second sending module is used to generate a fault code and send the fault code to the background server if the update of the left and right steering wheel limit angles fails.

[0149] It should be noted that the specific implementation of the rack end protection device 300 in this application embodiment refers to the specific implementation of the rack end protection method proposed in the first aspect of the above-mentioned application embodiment, and will not be repeated here.

[0150] Thirdly, based on the same inventive concept, embodiments of this application provide a storage medium storing machine-executable instructions, which, when executed by a processor, implement the rack end protection method proposed in the first aspect of this application.

[0151] It should be noted that the specific implementation of the storage medium in this application embodiment refers to the specific implementation of the rack end protection method proposed in the first aspect of the above-mentioned application embodiment, and will not be repeated here.

[0152] Fourthly, based on the same inventive concept, embodiments of this application provide a vehicle including a processor and a memory. The memory stores machine-executable instructions that can be executed by the processor, and the processor executes the machine-executable instructions to implement the rack end protection method proposed in the first aspect of this application.

[0153] It should be noted that the specific implementation method of the vehicle in this application embodiment refers to the specific implementation method of the rack end protection method proposed in the first aspect of the above-mentioned application embodiment, and will not be repeated here.

[0154] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, embodiments of the present invention can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of the present invention can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0155] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0156] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0157] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0158] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0159] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0160] The present invention has provided a detailed description of a rack end protection method, device, storage medium, and vehicle. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will know that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for protecting the end of a rack, characterized in that, The method includes: Get the steering wheel's rotation speed and angle in the current direction; Based on the rotational speed value and the steering wheel's steering limit angle in the current direction, the rack end protection angle range is determined; the rack end protection angle range is a closed interval composed of the rack end protection start angle and the rack end protection end angle. Based on the rotation angle value and the rack end protection angle range, determine the assist current limit value corresponding to the rotation angle value; If the assist current limit value is greater than the target assist current, the target assist current is output as the final assist current; otherwise, the assist current limit value is output as the final assist current. When the vehicle meets the learning conditions for steering limit angle, the original left steering limit angle and right steering limit angle of the steering wheel are updated according to the preset steering limit angle self-learning strategy. When the vehicle meets the learning conditions for steering limit angles, the existing left and right steering limit angles of the steering wheel are updated according to a preset self-learning strategy for steering limit angles, including: When the vehicle meets the learning conditions for steering limit angle, a learning command is sent through the host computer. The electric power steering system sets the steering limit angle learning flag to not learned, clears the original left steering limit angle and right steering limit angle of the steering wheel, controls the steering gear to turn to the left limit position and right limit position respectively, holds for a preset time, stores the new left steering limit angle and right steering limit angle, and updates the original left steering limit angle and right steering limit angle of the steering wheel. The step of determining the rack end protection angle range based on the rotational speed value and the steering wheel's steering limit angle in the current direction includes: Determine the fixed difference between the starting angle and the fixed difference between the ending angle corresponding to the rotational speed value; different rotational speed values ​​correspond to different fixed differences between the starting angle and the ending angle. Based on the fixed difference between the steering limit angle and the starting angle, the starting angle for rack end protection in the current direction is determined; and based on the fixed difference between the steering limit angle and the ending angle, the ending angle for rack end protection in the current direction is determined. The range of rack end protection angles is determined based on the rack end protection start angle and the rack end protection end angle.

2. The rack end protection method according to claim 1, characterized in that, The step of determining the assist current limit value corresponding to the rotation angle value based on the rotation angle value and the rack end protection angle range includes: When the rotation angle value does not enter the protection angle range of the rack end, the assist current limit value is maintained at the rated current value of the assist motor; After the angle value enters the protection angle range of the rack end, the assist current limit value decreases from the rated current value to the minimum assist current limit value at a fixed slope, and when the angle value is greater than the rack end protection termination angle, the assist current limit value remains at the minimum assist current limit value.

3. The rack end protection method according to claim 1, characterized in that, The method further includes: Based on the updated left turn limit angle, update the original rack end protection angle range in the left turn direction; based on the updated right turn limit angle, update the original rack end protection angle range in the right turn direction.

4. The rack end protection method according to claim 3, characterized in that, The steps of updating the original rack end protection angle range in the left turn direction based on the updated left turn limit angle and updating the original rack end protection angle range in the right turn direction based on the updated right turn limit angle include: Determine the first difference between the original left turn limit angle and the updated left turn limit angle, and the second difference between the original right turn limit angle and the updated right turn limit angle; Based on the first difference, update the original rack end protection angle range in the left turn direction; based on the second difference, update the original rack end protection angle range in the right turn direction.

5. The rack end protection method according to claim 4, characterized in that, Based on the first difference, update the original rack end protection angle range in the left turn direction; Based on the second difference, the step of updating the original rack end protection angle range in the right turn direction includes: Add the first difference to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the left turn direction, respectively, to obtain the updated rack end protection angle range in the left turn direction. The second difference is added to the rack end protection start angle and rack end protection end angle corresponding to the original rack end protection angle range in the right turn direction to obtain the updated rack end protection angle range in the right turn direction.

6. The rack end protection method according to claim 3, characterized in that, After the step of updating the left and right steering wheel limit angles according to a preset steering limit angle self-learning strategy, when the vehicle meets the steering limit angle learning conditions, the method further includes: Once it is confirmed that the left and right steering limit angles of the steering wheel have been successfully updated, the updated left and right steering limit angles will be sent to the backend server. If it is determined that the left and right steering wheel limit angles have failed to be updated, a fault code is generated and sent to the background server.

7. A rack end protection device, characterized in that, The device includes: The parameter acquisition module is used to obtain the steering wheel's rotation speed and angle values ​​in the current direction; The first determining module is used to determine the rack end protection angle range based on the rotation speed value and the steering wheel's steering limit angle in the current direction; the rack end protection angle range is a closed interval composed of the rack end protection start angle and the rack end protection end angle; The second determining module is used to determine the assist current limit value corresponding to the rotation angle value based on the rotation angle value and the rack end protection angle range; The current output module is used to output the target assist current as the final assist current when the assist current limit value is greater than the target assist current; otherwise, it outputs the assist current limit value as the final assist current. The limit angle update module is used to update the original left and right steering wheel limit angles according to a preset steering limit angle self-learning strategy when the vehicle meets the steering limit angle learning conditions. When the vehicle meets the learning conditions for steering limit angles, the existing left and right steering limit angles of the steering wheel are updated according to a preset self-learning strategy for steering limit angles, including: When the vehicle meets the learning conditions for steering limit angle, a learning command is sent through the host computer. The electric power steering system sets the steering limit angle learning flag to not learned, clears the original left steering limit angle and right steering limit angle of the steering wheel, controls the steering gear to turn to the left limit position and right limit position respectively, holds for a preset time, stores the new left steering limit angle and right steering limit angle, and updates the original left steering limit angle and right steering limit angle of the steering wheel. The first determining module includes: The fixed difference determination submodule is used to determine the fixed difference between the starting angle and the ending angle corresponding to the rotational speed value; different rotational speed values ​​correspond to different fixed differences between the starting angle and the ending angle. An angle determination submodule is used to determine the starting angle of rack end protection in the current direction based on the fixed difference between the steering limit angle and the starting angle; and to determine the ending angle of rack end protection in the current direction based on the fixed difference between the steering limit angle and the ending angle. The range determination submodule is used to determine the range of the rack end protection angle based on the rack end protection start angle and the rack end protection end angle.

8. A storage medium, characterized in that, The storage medium stores machine-executable instructions, which, when executed by a processor, implement the rack end protection method as described in any one of claims 1-6.

9. A vehicle, characterized in that, It includes a processor and a memory, the memory storing machine-executable instructions that can be executed by the processor, the processor executing the machine-executable instructions to implement the rack end protection method as described in any one of claims 1-6.

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