Method for determining tail end position of steering wheel rack and related device

Abstract

The embodiment of the invention provides a method for determining the tail end position of a steering wheel rack and a related device. The method comprises the steps of obtaining a first angle of a steering wheel corresponding to a first position of a rack and a second angle of the steering wheel corresponding to a second position; and determining a first target position and a second target position according to the actual turning angle of the steering wheel, the first angle corresponding to the first position and the second angle corresponding to the second position. Wherein the first position and the second position are determined according to the preset tail end position of the rack, and the first target position and the second target position are the actual tail end positions corresponding to the rack respectively. According to the embodiment of the invention, the actual rotation angle of the steering wheel is compared with the preset tail end position of the rack, so that the actual tail end position of the rack is determined. And then the tail end of the rack is protected according to the actual tail end position of the rack, and the stability and safety of the electric power steering system are improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method for determining the end position of a steering wheel rack and a related device. Background Art

[0002] When a vehicle turns the steering wheel, the wheels are usually rotated by the left and right movement of the rack, thereby achieving the steering of the vehicle. The rack is set in the housing of the rack-type steering gear, and the two ends of the rack pass through the housing and the ends are connected to the inner ball head tie rod. When the steering wheel is turned to the left and right extreme positions, the end of the rack may hit the housing. When the end of the rack collides with the housing, on the one hand, it will increase the resistance of the steering wheel and affect the user's operating feel. On the other hand, frequent collisions will affect the service life of components such as the rack and affect driving safety.

[0003] In order to avoid the rack from colliding with the housing, the end position of the rack is usually pre-configured in the vehicle. Therefore, during the movement of the rack, the end position of the rack can be used to determine whether the end of the rack is approaching the housing. When it is approaching the housing, the power torque output by the electric power steering system to the rack can be reduced to avoid the rack from colliding with the housing. Because the rack will deviate left and right during the movement, the end position of the rack will change. How to determine the actual position of the end of the rack is an urgent problem to be solved. Summary of the invention

[0004] The embodiment of the present application provides a method and a related device for determining the end position of a steering wheel rack. The actual end position of the rack is determined according to the actual steering wheel angle, and then the power torque of the electric power steering system is controlled according to the actual end position of the rack, thereby improving the safety and stability of the electric power steering system.

[0005] In a first aspect, an embodiment of the present application provides a method for determining a position of an end of a steering wheel rack, the method comprising:

[0006] Acquire a first angle of the steering wheel corresponding to a first position of the rack and a second angle of the steering wheel corresponding to a second position, wherein the distance between the first position and a first end position of the rack is less than or equal to a first preset distance, the distance between the second position and a second end position of the rack is less than or equal to a second preset distance, and the first end position and the second end position are preset end positions corresponding to the rack respectively;

[0007] Obtaining an actual turning angle of the steering wheel;

[0008] The first target position and the second target position are determined according to the actual angle of the steering wheel, the first angle and the second angle, wherein the actual angle of the steering wheel is used to drive the rack to move, and the first target position and the second target position are the actual end positions corresponding to the rack respectively.

[0009] In the above method, the first end position and the second end position are the preset end positions of the rack, and the actual angle of the steering wheel is the angle generated when the vehicle actually turns the steering wheel. Since the rotation of the steering wheel can drive the rack to move, the movement stroke of the rack to the end can be characterized according to the angle when the steering wheel is turned to the extreme position, so as to determine the position of the rack end according to the movement stroke of the rack to the end. That is, the actual angle of the steering wheel can be used to determine the actual end position of the rack. Furthermore, according to the actual angle of the steering wheel and the preset first angle and the preset second angle, the accuracy of the obtained rack end position can be made higher.

[0010] In an optional solution of the first aspect, after determining the first target position and the second target position according to the actual steering wheel angle, the first angle, and the second angle, the method further includes:

[0011] The assist torque of the electric power steering system is controlled according to the first target position and the second target position.

[0012] In the above method, the electric power steering system is controlled according to the first target position and the second target position, which is equivalent to protecting the end of the rack according to the actual end position of the rack. Compared with the prior art, in which the end of the rack is protected at a fixed position, the present application takes into account the situation that the end of the rack may be offset. The end protection is performed on the basis of determining the actual position of the end of the rack, which is more in line with the actual state of the vehicle. The present application is easy to implement and has low cost. It also improves the safety, stability, adaptability and versatility of the electric power steering system.

[0013] In an optional solution of the first aspect, the actual rotation angle of the steering wheel includes a first rotation angle and a second rotation angle, and determining the first target position and the second target position according to the actual rotation angle of the steering wheel, the first angle, and the second angle includes:

[0014] The direction corresponding to the first angle is consistent with the direction corresponding to the first angle, and the direction corresponding to the second angle is consistent with the direction corresponding to the second angle;

[0015] When the first rotation angle is greater than the first angle, determining the first target position according to the first rotation angle;

[0016] When the second rotation angle is greater than the second angle, the second target position is determined according to the second rotation angle.

[0017] In the above method, the first angle and the second angle are used as references to determine whether the actual steering wheel angle meets the requirements of the rack end position. Specifically, when the first steering wheel angle is greater than the first angle, the collected first angle meets the requirements, and the first target position can be determined based on the first angle. When the second steering wheel angle is greater than the second angle, the collected second angle meets the requirements, and the second target position can be determined based on the second angle.

[0018] In an optional solution of the first aspect, determining the first target position according to the first rotation angle includes:

[0019] determining a first deviation and a first total stroke according to the first rotation angle and the second angle, wherein the first deviation is used to represent an offset of a corresponding rack center relative to a midpoint of the rack when the steering wheel is at a zero position, and the first total stroke is used to represent a total stroke of the steering wheel;

[0020] When the first deviation is smaller than a first threshold and the first total stroke is smaller than a total stroke threshold, the rack position corresponding to the first rotation angle is used as the first target position.

[0021] In the above method, the judgment is made based on the first angle and the second angle of the steering wheel, which is equivalent to whether the offset of the rack center and the total stroke of the steering wheel meet the requirements when the first angle is replaced by the first angle of the steering wheel. The first angle of the steering wheel can replace the first angle only when the first deviation and the first total stroke are both less than the corresponding threshold. The accuracy and credibility of the collected steering wheel angle are guaranteed, and the error in determining the first target position is reduced.

[0022] In an optional solution of the first aspect, determining the first target position according to the first rotation angle includes:

[0023] Acquire a first torque of a steering wheel and a first rotation speed of the steering wheel, wherein the first torque of the steering wheel and the first rotation speed of the steering wheel correspond to a first rotation angle of the steering wheel;

[0024] When the first torque is greater than a torque threshold and the first rotation speed is less than a rotation speed threshold, the first target position is determined according to the first rotation angle.

[0025] In the above method, it is determined again whether the steering wheel angle meets the requirements of the rack end position according to the steering wheel torque and the steering wheel speed. If the steering wheel torque is too small, the steering wheel angle may not reach the limit of the steering wheel, so the steering wheel torque needs to be greater than the torque threshold. At the same time, if the steering wheel speed is too large, it may affect the vehicle's acquisition of the first angle, so the steering wheel speed needs to be less than the speed threshold. The stability and accuracy of the sampling process are guaranteed, and the efficiency of determining the rack end position is improved.

[0026] In an optional solution of the first aspect, determining the second target position according to the second rotation angle includes:

[0027] determining a second deviation and a second total stroke according to the second rotation angle and the first angle, wherein the second deviation is used to represent the offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position, and the second total stroke is used to represent the total stroke of the steering wheel;

[0028] When the second deviation is smaller than a second threshold and the second total stroke is smaller than the total stroke threshold, the rack position corresponding to the second rotation angle is used as the second target position.

[0029] In the above method, the judgment is made based on the second angle and the first angle of the steering wheel, which is equivalent to whether the offset of the rack center and the total stroke of the steering wheel meet the requirements when the second angle is replaced by the second angle of the steering wheel. The second angle of the steering wheel can replace the second angle only when the second deviation and the second total stroke are both less than the corresponding thresholds. The accuracy and credibility of the collected steering wheel angle are guaranteed, and the error in determining the second target position is reduced.

[0030] In an optional solution of the first aspect, determining the second target position according to the second rotation angle includes:

[0031] Acquire a second torque of the steering wheel and a second rotation speed of the steering wheel, wherein the second torque of the steering wheel and the second rotation speed of the steering wheel correspond to a second angle of the steering wheel;

[0032] When the second torque is greater than the torque threshold and the second rotation speed is less than the rotation speed threshold, a second target position is determined according to the second rotation angle.

[0033] In the above method, whether the steering wheel angle meets the requirements of the rack end position is determined again based on the steering wheel torque and the steering wheel speed. If the steering wheel torque is too small, the steering wheel angle may not reach the limit of the steering wheel, so the steering wheel torque needs to be greater than the torque threshold. At the same time, if the steering wheel speed is too large, it may affect the vehicle's acquisition of the second angle, so the steering wheel speed needs to be less than the speed threshold. The stability and accuracy of the sampling process are guaranteed, and the efficiency of determining the rack end position is improved.

[0034] In an optional scheme of the first aspect, the difference between the angle corresponding to the first target position and the angle corresponding to the second target position is less than or equal to a third threshold, wherein the third threshold is used to represent the maximum offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position.

[0035] In the above method, the deviation of the rack center corresponding to the first target position and the second target position needs to be less than the maximum offset. Since the first target position and the second target position are determined separately, although the first target position and the second target position meet their respective conditions, the rack determined according to the first target position and the second target position may have errors and fail to meet the overall conditions. Therefore, considering whether the first target position and the second target position meet the requirements at the same time, the accuracy of the first target position and the second target position is again guaranteed.

[0036] In an optional solution of the first aspect, the first position is determined according to the difference between the distance corresponding to the first end position and the first preset distance;

[0037] The second position is determined according to the difference between the distance corresponding to the second end position and the second preset distance.

[0038] In the above method, the second turning angle is used as an example for explanation. If the second turning angle is less than the angle corresponding to the second end position, there may be two situations. The first is that the second turning angle is less than the angle of the steering wheel turning from the zero position to the right limit, that is, the user has not turned the steering wheel to the right limit at this time. The second is that the rack has shifted to the left. So in this case, the vehicle cannot determine which of the above situations is the reason that causes the second turning angle to be less than the second angle at this time, and the vehicle cannot determine the second target position. Therefore, in order to avoid the above problems, the embodiment of the present application introduces the first position and the second position, and the second position is used as an example for explanation. When the second turning angle is less than the angle corresponding to the second position, the vehicle determines that the second turning angle is less than the angle of the steering wheel turning from the zero position to the right limit, that is, the vehicle determines that the user has not turned the steering wheel to the right limit at this time, and the collected second turning angle is invalid. When the second turning angle is greater than the angle corresponding to the second position and less than the angle corresponding to the second end position, the vehicle determines that the rack has shifted to the left, and the vehicle can determine the second target position according to the second turning angle in this case.

[0039] In a second aspect, an embodiment of the present application provides a device for determining the end position of a steering wheel rack, the device comprising a processor and a memory, the processor being coupled to the memory, the memory being used to store a computer program, the processor being used to call and run the computer program, so that the vehicle executes the method described in any one of the first aspects above.

[0040] In a third aspect, an embodiment of the present application provides a vehicle, comprising a steering system and a device for determining an end position of a steering wheel rack as described in the second aspect.

[0041] In a fourth aspect, an embodiment of the present application provides a computing device, comprising a processor and a memory; the processor is coupled to the memory, the memory is used to store a computer program, and the processor is used to call and run the computer program so that the computing device executes the method described in any one of the first aspects above.

[0042] Optionally, the computing device further comprises a communication interface, wherein the communication interface is used to receive and / or send data, and / or the communication interface is used to provide input and / or output for the processor.

[0043] It should be noted that the above embodiment is described by taking a processor (or general-purpose processor) that executes the method by calling a computer specification as an example. In the specific implementation process, the processor can also be a dedicated processor, in which case the computer instructions have been pre-loaded in the processor. Optionally, the processor can also include both a dedicated processor and a general-purpose processor.

[0044] Optionally, the processor and the memory may also be integrated into one device, that is, the processor and the memory may also be integrated together.

[0045] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. When the computer program runs on a computer or a processor, the method described in any one of the first aspects above is implemented.

[0046] The beneficial effects of the technical solutions provided in the second to fifth aspects of the present application can refer to the beneficial effects of the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The following is a brief introduction to the drawings required for describing the embodiments.

[0048] Figure 1 is a schematic diagram of the architecture of a vehicle provided in an embodiment of the present application;

[0049] Figure 2 It is a flow chart of a method for determining the end position of a steering wheel rack provided in an embodiment of the present application;

[0050] Figure 3 is a schematic diagram of determining whether the end position of the rack can be determined provided by an embodiment of the present application;

[0051] Figure 4 is a schematic diagram of an end position provided in an embodiment of the present application;

[0052] Figure 5 is a schematic diagram of determining a first target position provided by an embodiment of the present application;

[0053] Figure 6 is a schematic diagram of determining a second target position provided by an embodiment of the present application;

[0054] Figure 7 is a schematic diagram of a self-learning rack end provided in an embodiment of the present application;

[0055] Figure 8 This is a block diagram of the functional units of a device for determining the end position of a steering rack provided in an embodiment of the present application;

[0056] Fig. 9 It is a structural diagram of a computing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0057] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0058] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0059] In order to facilitate the understanding of the embodiments of the present application, the technical problems that the present application specifically aims to solve are analyzed and proposed below.

[0060] With the continuous improvement of vehicle electrification and intelligence, the requirements for the safety and reliability of the Electric Power Steering (EPS) system are becoming higher and higher. For example, in the advanced driver assistance and automatic driving functions of the vehicle, the requirements for the steering wheel rotation speed have increased, and the driving safety corresponding to the high speed of the steering wheel has also been given more attention. The vehicle applies a power torque to the rack through the electric power steering system according to parameters such as the steering wheel angle and the steering wheel speed to drive the rack to move left or right. Thus, the left and right movement of the rack can drive the wheels to rotate.

[0061] The rack is arranged in the housing of the rack-type steering gear, and the two ends of the rack pass through the housing and the ends are connected to inner ball head tie rods. When the steering wheel is turned to the left or right extreme positions, the end of the rack may hit the housing. In order to avoid the collision between the rack and the housing, the end position of the rack is usually pre-configured in the vehicle. Therefore, during the movement of the rack, it can be determined whether the end of the rack is approaching the housing according to the end position of the rack. When it is approaching the housing, the power torque output by the electric power steering system to the rack can be reduced to avoid the collision between the rack and the housing. Because the rack will deviate left and right during the movement, the end position of the rack will change. Therefore, the timing of reducing the power torque output by the electric power steering system to the rack determined according to the pre-configured end position of the rack may still cause the end of the rack to collide, affecting the user experience during use.

[0062] For example, in situations including but not limited to the following: rack fatigue, rack wear, vehicle maintenance, and vehicle four-wheel alignment, the position of the rack end may change, and the two ends of the rack may not be symmetrical with the center of the steering wheel. Generally, a protection area is set at the end of the rack to solve the problem of collision at the end of the rack. However, when the position of the rack end changes, the fixed position protection area is difficult to avoid mechanical impact at the rack end, thereby affecting the steering of the vehicle.

[0063] In one implementation, the vehicle selects the corresponding power-assist current limiting curve based on the steering wheel speed, and limits the power-assist current of the EPS in the rack end protection area according to the above-mentioned power-assist current limiting curve, thereby reducing the power-assist current used by the motor for steering to avoid collision at the rack end. However, since the position of the protection area is fixed, the possibility of collision at the rack end cannot be avoided when the position of the rack end changes. In addition, it is necessary to calibrate the power-assist current limiting curve according to different steering wheel speeds, which is labor-intensive and difficult to implement. Therefore, before protecting the rack end of the EPS, it is necessary to first determine the specific position of the rack end.

[0064] In summary, the embodiment of the present application provides a method for determining the end position of a steering wheel rack. The vehicle determines the first position according to a pre-configured first end position, and determines the second position according to a pre-configured second end position. The first end position and the second end position are pre-set end positions corresponding to the rack, respectively. Then, the vehicle determines the actual end position of the rack according to the actual steering wheel angle, the first angle corresponding to the first position, and the second angle corresponding to the second position.

[0065] The following is an introduction to the system architecture of the embodiment of the present application. It should be noted that the system architecture and business scenarios described in this application are intended to more clearly illustrate the technical solution of this application, and do not constitute a limitation on the technical solution provided by this application. It is known to those skilled in the art that with the evolution of the system architecture and the emergence of new business scenarios, the technical solution provided by this application is also applicable to similar technical problems.

[0066] See also Figure 1 , Figure 1 Schematic diagram of a vehicle structure provided by an embodiment of the present application. Figure 1 As shown, the vehicle 10 includes an Electric Power Steering (EPS) system 101 and a Torque Angle Sensor (TAS) 102 .

[0067] The vehicle 10 may be a vehicle driven by electric energy, a vehicle driven by fuel, or a vehicle driven by new energy hybrid power. Exemplarily, when the vehicle 10 is a vehicle driven by electric energy, it may be a new energy vehicle, such as a pure electric vehicle, an extended-range electric vehicle, a hybrid vehicle, a fuel cell electric vehicle, etc. When the vehicle 10 is a vehicle driven by fuel, it may be a car, an agricultural transport vehicle, a tractor, or a trailer, etc. When the vehicle 10 is a car, it may be a sedan, an off-road vehicle, a truck, a bus, or a van, etc.

[0068] EPS101 is a power steering system that relies on a power-assisted motor to provide a power-assisted torque. The power-assisted torque generated by the power-assisted motor assists the vehicle 10 in power steering, thereby reducing the driver's labor intensity and improving driving comfort and safety. The present application uses EPS101 to perform end protection according to the positions of the two ends of the rack. For example, in the process of steering the vehicle 10 by moving the rack left and right, when the rack approaches the end position, the power-assisted torque of EPS101 is reduced to avoid collision noise or damage to the mechanical parts when the mechanical parts collide. In addition, damage to EPS101 due to excessive temperature can also be avoided.

[0069] TAS102 is used to collect the steering wheel angle, steering wheel speed and steering wheel torque, etc. In addition, the steering wheel angle signal can also be collected by an angle sensor, and the steering wheel speed signal can also be collected by an angular velocity sensor, which is not limited here.

[0070] TAS 102 is also used to send the collected steering wheel angle, steering wheel speed and steering wheel torque to vehicle 10 and / or EPS 101 .

[0071] In one implementation, the vehicle 10 receives a first angle and a second angle of a steering wheel from the TAS 102. When the first angle is greater than the first angle, a first target position is determined according to the first angle of the steering wheel. When the second angle of the steering wheel is greater than the second angle, a second target position is determined according to the second angle of the steering wheel. Then, the vehicle 10 sends the first target position and the second target position to the EPS 101, and the EPS 101 performs end protection on the rack according to the first target position and the second target position.

[0072] In one implementation, EPS101 receives a first steering wheel angle and a second steering wheel angle from TAS102. When the first steering wheel angle is greater than the first angle, a first target position is determined according to the first steering wheel angle. When the second steering wheel angle is less than the second angle, a second target position is determined according to the second steering wheel angle. Then, EPS101 uses the first target position and the second target position as the end positions of the rack, respectively, and when the rack approaches the end position, the assist torque is reduced to avoid collision noise or damage to the mechanical parts when the mechanical parts collide.

[0073] See also Figure 2 , Figure 2 is a flow chart of a method for determining the end position of a steering wheel rack provided in an embodiment of the present application, and the method is applied to Figure 1 The vehicle shown. Figure 2 As shown, the method includes but is not limited to the following steps:

[0074] Step S201, obtaining a first angle of the steering wheel corresponding to a first position of the rack and a second angle of the steering wheel corresponding to a second position.

[0075] The first end position is a preset end position of one end of the rack, and the second end position is a preset end position of the other end of the rack. The distance between the first position and the first end position is less than or equal to the first preset distance, and the distance between the second position and the second end position is less than or equal to the second preset distance. The first position corresponds to a first angle, and the second position corresponds to a second angle.

[0076] In one implementation, the positions of the two ends of the rack relative to the vehicle when the steering wheel is at the zero position can be respectively used as the first end position and the second end position. Since turning the steering wheel can drive the rack to move, the steering wheel angle can be used to characterize the position of any point on the rack. For example, when the steering wheel is turned leftward from the zero position to the extreme position, the stroke of the rack driven by the steering wheel corresponds to the distance from the center of the rack to the left end position of the rack. Since the distance from the center of the rack to the left end position of the rack can be used to determine the end position of the left side of the rack, the steering wheel angle corresponding to the steering wheel turning from the zero position to the extreme position can be used to characterize the end position of the left side of the rack. For example, the steering wheel angle of the steering wheel turning from the zero position to the extreme position is 480°, and the angle corresponding to the end position on the left side of the rack is 480°. Therefore, the vehicle can use the left and right extreme theoretical values ​​of the steering wheel angle at the time of leaving the factory as the angle corresponding to the first end position of the rack and the angle corresponding to the second end position of the rack.

[0077] In a possible implementation, when the steering wheel's turning angle zero point is calibrated, the vehicle may determine the first end position and the second end position of the rack according to the total travel of the steering wheel.

[0078] Specifically, the total stroke of the steering wheel is the sum of the maximum angles at which the steering wheel can turn left or right during the steering process of the vehicle. When the steering wheel's turning angle is calibrated to zero, the left and right limits of the steering wheel's turning angle are symmetrical about the steering wheel's median, that is, the maximum angle at which the steering wheel rotates to the left is equal to the maximum angle at which the steering wheel rotates to the right, and the sum of the maximum angle at which the steering wheel rotates to the left and the maximum angle at which the steering wheel rotates to the right is the total stroke of the steering wheel. For example, the steering wheel can usually turn to a left limit of 480°, and to a right limit of 480°. Therefore, the total stroke of the steering wheel can be 960°. Since the stroke of the rack has a corresponding relationship with the steering wheel's turning angle, the stroke of the rack can be represented by the steering wheel's turning angle. For example, when the steering wheel rotates from the zero position to the left to the extreme position, the rack also moves to the left to the left end point of the rack through the gear. At this time, the stroke of the rack corresponds to the maximum rotation angle of the rack to the left; when the steering wheel rotates from the zero position to the right to the extreme position, the rack also moves to the right to the right end point of the rack through the gear. At this time, the stroke of the rack corresponds to the maximum rotation angle of the rack to the right.

[0079] Further, when the maximum angle of the steering wheel rotating to the left is equal to the maximum angle of the steering wheel rotating to the right, the stroke of the rack moving to the left and the stroke of the rack moving to the right through the pinion are also equal, and the sum of the stroke of the rack moving to the left and the stroke of the rack moving to the right is the total stroke of the rack. At this time, when the steering wheel is at the zero position, the corresponding center of the rack coincides with the midpoint of the rack, and the first end position of the rack and the second end position of the rack are symmetrical with the above-mentioned corresponding rack center. For example, if the total stroke of the steering wheel is 960°, then the angle corresponding to the total stroke of the rack is also 960°. Since the maximum angle of the steering wheel rotating to the left is equal to the maximum angle of the steering wheel rotating to the right, the maximum angle of the steering wheel rotating to the left and the maximum angle of the steering wheel rotating to the right are both 480°. Since the stroke of the rack has a corresponding relationship with the angle of the steering wheel, the angle corresponding to the first end position of the rack and the angle corresponding to the second end position are both 480°.

[0080] In a possible implementation, the vehicle determines the first position according to the difference between the distance corresponding to the first end position and the first preset distance, and determines the second position according to the difference between the distance corresponding to the second end position and the second preset distance.

[0081] Specifically, the distance corresponding to the first end position can be understood as the distance between the center of the rack corresponding to when the steering wheel is at the zero position and the first end position, and the distance corresponding to the second end position can be understood as the distance between the center of the rack corresponding to when the steering wheel is at the zero position and the second end position. The distance between the first position and the center of the rack corresponding to when the steering wheel is at the zero position is smaller than the distance corresponding to the first end position, so the first position can be determined based on the difference between the distance corresponding to the first end position and the first preset distance. The distance between the second position and the center of the rack corresponding to when the steering wheel is at the zero position is smaller than the distance corresponding to the second end position, so the second position can be determined based on the difference between the distance corresponding to the second end position and the second preset distance. Among them, the reason for setting the first position and the second position in the embodiment of the present application will be combined in step S202. Figure 4 Make an introduction.

[0082] The following will introduce whether the vehicle can determine the end position of the rack.

[0083] See also Figure 3 , Figure 3 Schematic diagram of a method for determining whether the end position of a rack can be determined provided by an embodiment of the present application. Figure 3 As shown, the vehicle first determines whether the steering wheel angle zero point is calibrated. For example, the vehicle can obtain the calibration status bit of the steering wheel angle zero point from the TAS, and determine whether the steering wheel angle zero point is calibrated according to the calibration status bit of the steering wheel angle zero point.

[0084] from Figure 3 It can be seen that when the steering wheel's zero angle point is not calibrated, the vehicle is not suitable for determining the rack end position according to the embodiment of the present application. This is because the steering wheel's zero angle point is calibrated so that when the steering wheel is at the zero point position, the left and right end positions of the rack are symmetrical about the rack center. If the steering wheel's zero angle point is not calibrated, the left and right end positions of the rack may not be symmetrical about the rack center. Since the first end position and the second end position are symmetrical about the rack center, the vehicle cannot determine the actual end position of the rack based on the first end position and the second end position if the steering wheel's zero angle point is not calibrated.

[0085] from Figure 3 It can also be seen that when the steering wheel angle zero point is determined and calibrated, there are the following situations:

[0086] Case 1: The vehicle determines whether the steering wheel angle is valid and whether there is no malfunction in the EPS system.

[0087] For example, the vehicle obtains a steering angle signal and a fault signal, determines whether the steering wheel angle is valid based on the steering angle signal, and determines whether the EPS system has a fault based on the fault signal.

[0088] Case 2: The vehicle determines whether the left end position of the rack has not been self-learned.

[0089] For example, to determine whether the left end position of the rack has not been self-learned, if the vehicle has not self-learned the left end position of the rack, the vehicle may use the first end position as the preset left end position of the rack.

[0090] Case 3: The vehicle determines whether the right end position of the rack has not been self-learned.

[0091] For example, to determine whether the right end position of the rack has not been self-learned, if the vehicle has not self-learned the right end position of the rack, the vehicle may use the second end position as the preset right end position of the rack.

[0092] like Figure 3 As shown, when conditions 1, 2 and 3 are all met, the vehicle can determine the end position of the rack, the self-learning enable of the left end position of the rack is triggered, and the self-learning enable of the right end position of the rack is triggered.

[0093] Step S202, obtaining the actual steering angle of the steering wheel.

[0094] In a possible implementation, the vehicle collects the steering wheel angle, steering wheel speed, steering wheel torque, etc. through TAS. In addition, the steering wheel angle signal can also be collected by an angle sensor, and the steering wheel speed signal can also be collected by an angular velocity sensor, which is not limited here.

[0095] Step S203, determining a first target position and a second target position according to the actual steering angle of the steering wheel, the first angle and the second angle.

[0096] The steering wheel angle is used to drive the rack to move, the first target position is the actual end position of one end of the rack, and the second target position is the actual end position of the other end of the rack.

[0097] The following will be combined Figure 4 The first end position, the second end position, the first position, the second position, the first target position and the second target position are specifically introduced.

[0098] See also Figure 4 , Figure 4 Schematic diagram of an end position provided in an embodiment of the present application. Figure 4As shown, the left end position and the right end position of the rack that has not been offset are symmetrical about the center of the first rack, and the center of the first rack coincides with the midpoint of the rack that has not been offset. The center of the first rack is the center of the rack corresponding to when the steering wheel is at the zero position.

[0099] The first end position and the second end position may correspond to Figure 4 The first end position is the left end position of the rack that has not been offset. For example, the second end position is the right end position of the rack that has not been offset. Figure 4 As shown, the distance between the first position and the first end position is less than or equal to the first preset distance, and the distance between the second position and the second end position is less than or equal to the second preset distance. For example, if the total travel of the steering wheel is 960°, the unilateral travel of the steering wheel is 480°. In a rack that has not been offset, the angle corresponding to the left end position, that is, the first end position, is equal to the unilateral travel of the steering wheel. Similarly, the angle corresponding to the right end position, that is, the second end position, is also equal to the unilateral travel of the steering wheel. Assuming that the angle corresponding to the first preset distance is 10°, that is, the steering wheel needs to rotate 10° for the rack to move from the first position to the first end position. Then the first angle corresponding to the first position is 470°. Assuming that the angle corresponding to the second preset distance is 10°, that is, the steering wheel needs to rotate 10° for the rack to move from the second position to the second end position. Then the second angle corresponding to the second position is 470°.

[0100] The first target position and the second target position correspond to the actual end positions of the rack, respectively, taking the rack shifting to the left as an example. Figure 4 In the embodiment, the non-shifted rack and the shifted rack are the same rack, but the shifted rack is shifted to the left compared to the non-shifted rack, so the position of the rack end relative to the vehicle also changes. For example, the actual left end of the shifted rack corresponds to the first target position, and the actual right end corresponds to the second target position. The purpose of the embodiment of the present application is to determine the actual end position (e.g., the first target position and the second target position) based on the preset end position (e.g., the first end position and the second end position).

[0101] In a possible implementation, the actual rotation angle of the steering wheel includes a first rotation angle and a second rotation angle, the direction corresponding to the first rotation angle is consistent with the direction corresponding to the first angle, and the direction corresponding to the second rotation angle is consistent with the direction corresponding to the second angle. When the first rotation angle is greater than the first angle, the first target position is determined according to the first rotation angle. When the second rotation angle is greater than the second angle, the second target position is determined according to the second rotation angle.

[0102] Specifically, the actual steering wheel angle can be the angle generated by the user turning the steering wheel left or right. For example, the user turns the steering wheel to the left, and the vehicle determines the angle the user turns as the first angle. The user turns the steering wheel to the right, and the vehicle determines the angle the user turns as the second angle. Since the vehicle needs to determine the actual end position of the rack, the steering wheel needs to be rotated from the zero position to the extreme position. For example, the steering wheel is rotated from the zero position to the left extreme, and the travel of the rack movement can be the rack center (for example Figure 4 Therefore, the first target position can be determined according to the angle of the steering wheel turning from the zero position to the left limit. The travel of the rack that can be driven by the steering wheel turning from the zero position to the right limit is the rack center (for example Figure 4 Therefore, the second target position can be determined according to the angle at which the steering wheel is turned right from the zero position to the right limit.

[0103] Since the first turning angle and the second turning angle are the angles generated by the user turning the steering wheel, the user may not turn the steering wheel to the extreme position due to an operational error. For example, if the angle at which the user turns the steering wheel to the right is the second turning angle, and the user does not turn the steering wheel from the zero position to the right extreme. Then, the second turning angle will be smaller than the angle at which the steering wheel turns right from the zero position to the right extreme. If the second turning angle in this case is regarded as the angle at which the steering wheel turns right from the zero position to the right extreme to determine the second target position, then the determined second target position is inaccurate. Therefore, the vehicle needs to first determine whether the second turning angle corresponds to the angle at which the steering wheel turns right from the zero position to the right extreme. When determining that the second turning angle corresponds to the angle at which the steering wheel turns right from the zero position to the right extreme, the vehicle can determine the second target position based on the second turning angle.

[0104] For example, Figure 4 For example, if the second turning angle is smaller than the angle corresponding to the second end position, there may be two situations. The first is that the second turning angle is smaller than the angle of the steering wheel turning from the zero position to the right limit, that is, the user has not turned the steering wheel to the right limit. The second is that the rack has shifted to the left, for example Figure 4The stroke corresponding to the second target position is smaller than the second end position. Therefore, in this case, the vehicle cannot determine which of the above situations is the reason that causes the second turning angle to be smaller than the angle corresponding to the second end position, and the vehicle cannot determine the second target position. Therefore, in order to avoid the above problems, the embodiment of the present application introduces the first position and the second position, and the second position is used as an example for explanation. When the second turning angle is smaller than the angle corresponding to the second position, the vehicle determines that the second turning angle is smaller than the angle of the steering wheel turning from the zero position to the right limit, that is, the vehicle determines that the user has not turned the steering wheel to the right limit at this time, and the collected second turning angle is invalid. When the second turning angle is greater than the angle corresponding to the second position and less than the angle corresponding to the second end position, the vehicle determines that the rack has shifted to the left, and the vehicle can determine the second target position based on the second turning angle in this case.

[0105] In a possible implementation, the vehicle determines the first deviation and the first total stroke according to the first turning angle and the second angle. When the first deviation is less than the first threshold and the first total stroke is less than the total stroke threshold, the rack position corresponding to the first turning angle of the steering wheel is used as the first target position.

[0106] The first deviation is used to indicate the offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position, and the first total stroke is used to indicate the total stroke of the steering wheel.

[0107] In a possible implementation, the relative position of the center of the first rack and the midpoint of the rack can be used to determine whether the rack is offset. This is because the midpoint of the rack of an offset rack does not coincide with the center of the first rack. For example, Figure 4 In the rack that has not been offset, the point coincides with the center of the first rack. In the rack that has not been offset, the point coincides with the center of the first rack. Therefore, it can be judged whether the rack has been offset according to the relative position of the center of the first rack and the midpoint of the rack.

[0108] For example, if Figure 4 As shown, the midpoint of the offset rack is also offset to the left relative to the center of the first rack, and the offset amount can be measured according to the following expression (1):

[0109] Offset of rack center = (AO-BO) / 2 (1)

[0110] Among them, point A is the left end position of the offset rack (i.e., the first target position to be determined), and point B is the right end position of the offset rack (i.e., the second target position to be determined). AO is the value corresponding to the extreme angle of rotation of the steering wheel from the zero position to the left end position of the offset rack, i.e., the first angle, and BO is the value corresponding to the extreme angle of rotation of the steering wheel from the zero position to the right end position of the offset rack, i.e., the second angle. The offset of the rack center can be the rack stroke corresponding to the rack midpoint and the first rack center. Among them, the first rack center is related to the zero position of the steering wheel, so the first rack center of the non-offset rack and the offset rack are consistent.

[0111] According to the above expression (1) for measuring rack offset, an expression for the first deviation can be obtained. For example, the first deviation can be the absolute value of the sum of the first steering angle and the second steering angle of the steering wheel. The vehicle determines whether the first deviation is less than the first threshold according to the following expression:

[0112] First deviation = |first rotation angle + second angle| < first threshold

[0113] Among them, in order to distinguish whether the steering wheel is turning to the left or right, a positive value is set for turning to the left and a negative value is set for turning to the right. Therefore, the first angle to the left is a positive value, and the second angle to the right is a negative value. Since the vehicle can determine the offset of the rack center according to the above expression (1), that is, the offset of the rack center is determined according to the difference between the limit travel of the steering wheel turning to the left and the limit travel of the steering wheel turning to the right. Since the limit travel of the steering wheel turning in the direction of the second target position is temporarily unknown, the limit travel of the steering wheel turning in the direction of the second target position can be replaced by the second angle. And the first angle of the steering wheel is a positive value, and the second angle is a negative value, so the absolute value of the sum of the first angle and the second angle of the steering wheel can be used to represent the offset of the rack center. When the first deviation is less than the first threshold, the first angle of the steering wheel meets the requirement of rack center offset.

[0114] Exemplarily, the first total stroke may be the sum of the absolute value of the first steering angle and the absolute value of the second steering angle. For example, the vehicle determines whether the first total stroke is less than the total stroke threshold according to the following expression:

[0115] First total stroke = |first rotation angle|+|second angle|<total stroke threshold

[0116] Among them, since the limit stroke of the steering wheel turning in the direction of the second target position is not yet known, the limit stroke of the steering wheel turning in the direction of the second target position can be replaced by the second angle. That is, the sum of the numerical value of the first angle of the steering wheel and the numerical value of the second angle corresponds to the total stroke of the steering wheel, which needs to be less than the total stroke threshold of the steering wheel. Exemplarily, since the stroke of the rack has a corresponding relationship with the angular stroke of the steering wheel, the total stroke threshold can be the sum of the theoretical design total stroke of the rack and the first threshold. Among them, the first threshold is used to determine the deviation range. For example, the theoretical design total stroke of the rack is 960°, and the first threshold is 20°.

[0117] In one implementation, when the first deviation is smaller than the first threshold and the first total stroke is smaller than the total stroke threshold, the acquired first rotation angle meets the requirement.

[0118] In one implementation, when the first deviation is smaller than the first threshold and the first total stroke is greater than or equal to the total stroke threshold, the acquired first rotation angle does not meet the requirement.

[0119] In one implementation, when the first deviation is greater than or equal to the first threshold and the first total stroke is less than the total stroke threshold, the acquired first rotation angle does not meet the requirement.

[0120] In one implementation, when the first deviation is greater than or equal to the first threshold and the first total stroke is greater than or equal to the total stroke threshold, the acquired first rotation angle does not meet the requirement.

[0121] In a possible implementation, when the first steering wheel angle meets the above conditions, the steering wheel speed and steering wheel torque corresponding to the first steering wheel angle also need to meet certain requirements. The vehicle can obtain the first steering wheel torque and the first steering wheel speed, and when the first steering wheel torque is greater than the torque threshold and the first steering wheel speed is less than the speed threshold, determine the first target position according to the first steering wheel angle. The first steering wheel torque is the torque corresponding to the first steering wheel angle, and the first steering wheel speed is the speed corresponding to the first steering wheel angle.

[0122] The vehicle can determine the first torque of the steering wheel and the first speed of the steering wheel according to the following expressions:

[0123] The first torque of the steering wheel > the torque threshold and the first speed of the steering wheel < the speed threshold

[0124] Specifically, if the torque of turning the steering wheel is too small, it is difficult to turn the steering wheel to the extreme position. Therefore, in order for the first turning angle of the steering wheel to be infinitely close to the extreme position, the steering wheel needs to be turned vigorously. That is, the first torque of the steering wheel needs to be greater than the torque threshold. Among them, the torque threshold can be 5N.m. Similarly, in order to facilitate the vehicle to self-learn the end position of the rack, the steering wheel needs to be turned at a lower speed, and the duration of turning the steering wheel vigorously and slowly is longer. For example, the speed threshold can be 15° / s, and the duration of turning the steering wheel vigorously and slowly exceeds 300ms.

[0125] In one implementation, when the first torque of the steering wheel is greater than a torque threshold and the first rotation speed of the steering wheel is less than a rotation speed threshold, the first steering angle is valid.

[0126] In one implementation, when the first torque of the steering wheel is less than or equal to a torque threshold and the first rotation speed of the steering wheel is less than a rotation speed threshold, the first steering angle is invalid.

[0127] In one implementation, when the first torque of the steering wheel is greater than a torque threshold and the first rotation speed of the steering wheel is greater than or equal to a rotation speed threshold, the first steering angle is invalid.

[0128] In one implementation, when the first torque of the steering wheel is less than or equal to a torque threshold and the first rotation speed of the steering wheel is greater than or equal to a rotation speed threshold, the first steering angle is invalid.

[0129] For example, see Figure 5 , Figure 5 is a schematic diagram of determining a first target position provided by an embodiment of the present application. Figure 5 As shown, the vehicle first determines the first position, and then determines whether the first steering angle of the steering wheel meets the requirement. Specifically, the vehicle can determine whether the first steering angle of the vehicle meets the requirement according to the following conditions:

[0130] |first rotation angle+second angle|<first threshold, and |first rotation angle|+|second angle|<theoretical designed total stroke of the rack+first threshold.

[0131] like Figure 5 As shown, when the first turning angle of the vehicle does not meet the above requirements, the first end position of the vehicle does not change. When the first turning angle of the vehicle meets the above requirements, the vehicle determines whether the first torque of the steering wheel and the first speed of the steering wheel meet the requirements according to the following expression:

[0132] The first torque of the steering wheel > the torque threshold, and the first speed of the steering wheel < the speed threshold

[0133] like Figure 5As shown, when the first torque of the steering wheel and / or the first rotation speed of the steering wheel do not meet the above requirements, the first end position of the vehicle does not change. When the first torque of the steering wheel and the first rotation speed of the steering wheel meet the above requirements, the vehicle determines the first target position according to the first rotation angle of the steering wheel.

[0134] In a possible implementation, the vehicle determines the second deviation and the second total stroke according to the second turning angle and the first angle. When the second deviation is less than the second threshold and the first total stroke is less than the total stroke threshold, the rack position corresponding to the second turning angle of the steering wheel is used as the second target position.

[0135] The second deviation is used to indicate the offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position, and the second total stroke is used to indicate the total stroke of the steering wheel.

[0136] Specifically, take the rack shifting to the left as an example. Figure 4 It can be seen that, compared with the non-shifted rack, the angle corresponding to the right end position (e.g., the second target position) of the shifted rack is greater than the second angle. The midpoint of the shifted rack is also shifted to the left relative to the center of the first rack. Therefore, according to the above expression (1) for measuring the rack offset, an expression for the second deviation can be obtained. For example, the second deviation can be the absolute value of the sum of the second steering angle and the first angle of the steering wheel. The vehicle determines whether the second deviation is less than the second threshold value according to the following expression:

[0137] second deviation=|second rotation angle+first angle|<second threshold

[0138] In order to distinguish whether the steering wheel is turning to the left or right, a positive value is set for turning to the left and a negative value is set for turning to the right. Therefore, the second angle is a negative value to the right and the first angle is a positive value to the left. Since the vehicle can determine the offset of the rack center according to the above expression (1), the offset of the rack center is determined according to the difference between the limit travel of the steering wheel turning to the left and the limit travel of the steering wheel turning to the right. Since the limit travel of the steering wheel turning in the direction of the first target position is unknown, the limit travel of the steering wheel turning in the direction of the first target position can be replaced by the first angle. And the second angle of the steering wheel is a negative value and the first angle is a positive value, so the absolute value of the sum of the second angle of the steering wheel and the first angle can be used to represent the offset of the rack center. When the second deviation is less than the second threshold, the second angle of the steering wheel meets the requirement of rack center offset. In which, the second threshold and the first threshold can be the same or different, for example, the second threshold can be 20°.

[0139] Exemplarily, the second total stroke may be the sum of the absolute value of the second steering angle and the absolute value of the first angle of the steering wheel. For example, the vehicle determines whether the second total stroke is less than the total stroke threshold according to the following expression:

[0140] Second total stroke = |second rotation angle| + |first angle| < total stroke threshold

[0141] Among them, since the limit stroke of the steering wheel turning in the direction of the first target position is not yet known, the limit stroke of the steering wheel turning in the direction of the first target position can be replaced by the first angle. That is, the sum of the value of the second angle of the steering wheel and the value of the first angle corresponds to the total stroke of the steering wheel, which needs to be less than the total stroke threshold of the steering wheel. Exemplarily, since the stroke of the rack has a corresponding relationship with the angular stroke of the steering wheel, the total stroke threshold can be the sum of the theoretical design total stroke of the rack and the second threshold. Among them, the second threshold is used to determine the deviation range. For example, the theoretical design total stroke of the rack is 960°, and the second threshold is 20°.

[0142] In one implementation, when the second deviation is smaller than the second threshold and the second total stroke is smaller than the total stroke threshold, the acquired second rotation angle meets the requirement.

[0143] In one implementation, when the second deviation is smaller than the second threshold and the second total stroke is greater than or equal to the total stroke threshold, the acquired second rotation angle does not meet the requirement.

[0144] In one implementation, when the second deviation is greater than or equal to the second threshold and the second total stroke is less than the total stroke threshold, the acquired second rotation angle does not meet the requirement.

[0145] In one implementation, when the second deviation is greater than or equal to the second threshold and the second total stroke is greater than or equal to the total stroke threshold, the acquired second rotation angle does not meet the requirement.

[0146] In a possible implementation, when the second angle of the steering wheel meets the above conditions, the rotation speed of the steering wheel and the torque of the steering wheel corresponding to the second angle of the steering wheel also need to meet certain requirements. The vehicle can obtain the second torque of the steering wheel and the second rotation speed of the steering wheel, and determine the second target position according to the second angle of the steering wheel when the absolute value of the second torque of the steering wheel is greater than the torque threshold and the absolute value of the second rotation speed of the steering wheel is less than the rotation speed threshold. Among them, the second torque of the steering wheel is the torque corresponding to the second angle of the steering wheel, and the second rotation speed of the steering wheel is the rotation speed corresponding to the second angle of the steering wheel. Since the second angle of the steering wheel is the angle at which the steering wheel rotates in the direction of the second target position, the second angle is a negative value. Correspondingly, the second torque of the steering wheel and the second rotation speed of the steering wheel are also negative values, so it is necessary to compare the absolute value of the second torque of the steering wheel and the absolute value of the second rotation speed of the steering wheel.

[0147] The vehicle can judge the second torque of the steering wheel and the second speed of the steering wheel according to the following expression:

[0148] |Second torque of the steering wheel|>torque threshold and |Second speed of the steering wheel|<speed threshold

[0149] Specifically, if the torque for turning the steering wheel is too small, it is difficult to turn the steering wheel to the extreme position. Therefore, in order for the second turning angle of the steering wheel to be infinitely close to the extreme position, the steering wheel needs to be turned vigorously. That is, the absolute value of the second torque of the steering wheel needs to be greater than the torque threshold. Among them, the torque threshold can be 5N.m. Similarly, in order to facilitate the vehicle to self-learn the end position of the rack, the steering wheel needs to be turned at a lower speed, and the duration of turning the steering wheel vigorously and slowly is longer. For example, the speed threshold can be 15° / s, and the duration of turning the steering wheel vigorously and slowly exceeds 300ms.

[0150] In one implementation, when the second torque of the steering wheel is greater than a torque threshold and the second rotation speed of the steering wheel is less than a rotation speed threshold, the second steering angle is valid.

[0151] In one implementation, when the second torque of the steering wheel is less than or equal to a torque threshold and the second rotation speed of the steering wheel is less than a rotation speed threshold, the second steering angle is invalid.

[0152] In one implementation, when the second torque of the steering wheel is greater than a torque threshold and the second rotation speed of the steering wheel is greater than or equal to a rotation speed threshold, the second steering angle is invalid.

[0153] In one implementation, when the second torque of the steering wheel is less than or equal to a torque threshold and the second rotation speed of the steering wheel is greater than or equal to a rotation speed threshold, the second steering angle is invalid.

[0154] For example, see Figure 6 , Figure 6 is a schematic diagram of determining a second target position provided by an embodiment of the present application. Figure 6 As shown, the vehicle first determines the second position, and then determines whether the second steering angle of the steering wheel meets the requirement. Specifically, the vehicle can determine whether the second steering angle of the steering wheel meets the requirement according to the following conditions:

[0155] |second rotation angle+first angle|<second threshold value, and |second rotation angle|+|first angle|<theoretical designed total stroke of the rack+second threshold value.

[0156] like Figure 6As shown, when the second turning angle of the vehicle does not meet the above requirements, the second end position of the vehicle does not change. When the second turning angle of the vehicle meets the above requirements, the vehicle then determines whether the second torque of the steering wheel and the second speed of the steering wheel meet the following requirements:

[0157] |Second torque of the steering wheel|>torque threshold, and |Second speed of the steering wheel|<speed threshold

[0158] like Figure 6 As shown, when the second torque of the steering wheel and / or the second rotation speed of the steering wheel do not meet the above requirements, the second end position of the vehicle does not change. When the second torque of the steering wheel and the second rotation speed of the steering wheel meet the above requirements, the vehicle determines the second target position according to the second rotation angle of the steering wheel.

[0159] After the vehicle determines the first target position according to the first turning angle and determines the second target position according to the second turning angle, the vehicle can further determine whether the obtained first target position and the second target position are accurate based on the determined first target position and the determined second target position.

[0160] In one possible implementation, the difference between the angle corresponding to the first target position and the angle corresponding to the second target position is less than or equal to a third threshold, wherein the third threshold is used to represent the maximum offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position.

[0161] The vehicle can determine the difference between the angle corresponding to the first target position and the angle corresponding to the second target position according to the following expression:

[0162]

[0163] According to the above expression (1), the offset of the rack center can be determined based on the value of the stroke from the center of the rack to the first target position when the steering wheel is at the zero position, and the value of the stroke from the center of the rack to the second target position when the steering wheel is at the zero position. In order to distinguish whether the steering wheel is turned left or right, set the left turn to a positive value and the right turn to a negative value. Therefore, the angle corresponding to the first target position is a positive value to the left, and the angle corresponding to the second target position is a negative value to the right. Therefore, according to the above expression, it can be determined whether the offset of the rack center meets the requirements based on the angle corresponding to the first target position and the angle corresponding to the second target position at the same time. When the angle corresponding to the first target position and the angle corresponding to the second target position meet the above requirements at the same time, the accuracy of the first target position and the second target position determined by the vehicle is high, and the result of the vehicle's self-learning of the rack end position is successful.

[0164] In a possible implementation, the vehicle may store a first target position of the rack and a second target position of the rack, and then protect the end of the rack according to the stored first target position and second target position.

[0165] For example, after the EPS is powered off, the vehicle can store the first target position of the rack and the second target position of the rack in an electrically erasable programmable read only memory (EEPROM). Among them, EEPROM is a storage chip that does not lose data after power failure. Existing information can be erased and reprogrammed on a computer or dedicated equipment, and the availability is high.

[0166] In a possible implementation, the vehicle controls the power-assisting torque of the electric power steering system according to the first target position and the second target position.

[0167] Specifically, the vehicle determines the protection torque according to the first target position and the second target position learned by itself, so as to perform end protection on the steering system. For example, when the rack approaches the first target position or the second target position, the vehicle can reduce the power torque of the electric power steering system to avoid collision noise or damage to the mechanical parts when the mechanical parts collide. In addition, damage caused by excessive temperature of the motor and controller can also be avoided.

[0168] For example, when the mechanical parts of the rack are fatigued or the end position changes due to wear, or when the vehicle is undergoing maintenance, the parameters of the four-wheel alignment are adjusted, etc., there may be obvious deviations in the protection range of the left and right ends of the rack. This will lead to inconsistent feel of the left and right steering ends, and in severe cases, problems such as knocking noise at the extreme positions will occur. According to an embodiment of the present application, the vehicle can self-learn the extreme positions of the two ends of the rack. Then, within a certain stroke of steering close to the extreme position, the impact speed of the steering gear rack on the end is slowed down by reducing the motor assist. It can better provide users with a sense of end damping, improve handling quality, and improve noise, vibration, and harshness (NVH) performance.

[0169] For example, see Figure 7 , Figure 7 Schematic diagram of a self-learning rack end provided in an embodiment of the present application. Figure 7 As shown, the step of determining the first target position of the rack and the second target position of the rack by the vehicle through self-learning includes any step from step 1 to step 7, which is as follows:

[0170] Step 1, self-learning enable triggering. The vehicle triggers the left end position learning enable and the right end position learning enable when determining that the rack end position is suitable for self-learning according to the current state.

[0171] Step 2, judging whether the first steering wheel angle meets the requirement, and judging whether the second steering wheel angle meets the requirement. The vehicle judges whether the first steering wheel angle meets the requirement based on the first steering wheel angle, the first steering wheel torque, and the first steering wheel speed. The vehicle can also judge whether the second steering wheel angle meets the requirement based on the second steering wheel angle, the second steering wheel torque, and the second steering wheel speed. The specific judgment conditions and judgment process can refer to the above embodiment.

[0172] Step 3: If the first steering wheel angle meets the requirements, determine the first target position according to the first steering wheel angle, and use the first target position as the left end position of the rack. In addition, the left end position learning status bit of the rack is valid, marked as CCW_Valid = 1. If the first steering wheel angle does not meet the requirements, the left end position of the rack is still the first end position, and the left end position learning status bit of the rack is invalid, marked as CCW_Valid = 0.

[0173] When the second steering wheel angle meets the requirements, the second target position is determined according to the second steering wheel angle, and the second target position is used as the right end position of the rack. In addition, the right end position learning status bit of the rack is valid, marked as CW_Valid = 1. When the second steering wheel angle does not meet the requirements, the right end position of the rack is still the second end position, and the right end position learning status bit of the rack is invalid, marked as CW_Valid = 0.

[0174] Step 4, output the left end position of the rack, the right end position of the rack, the left end position learning state and the right end position learning state.

[0175] Step 5, determine whether the left end position of the rack and the right end position of the rack meet the requirements. Among them, judgment condition 1, judgment condition 2 and judgment condition 3 are as follows:

[0176] Judgment condition 1: The angle corresponding to the left end position of the rack and the angle corresponding to the right end position of the rack both satisfy the following expression:

[0177] |(Lmax, Rmax)|<total travel of the steering wheel / 2+10°&|Lmax+Rmax| / 2<30°

[0178] Among them, Lmax is the angle corresponding to the left end position of the rack, and Rmax is the angle corresponding to the right end position of the rack. Both Lmax and Rmax must be less than the total travel of the steering wheel / 2+10°.

[0179] Judgment condition 2: The angle corresponding to the left end position of the rack and the angle corresponding to the right end position of the rack both satisfy the following expression:

[0180] |(Lmax, Rmax)|>total travel of the steering wheel / 2+10° and / or |Lmax+Rmax| / 2>30°

[0181] Among them, Lmax is the angle corresponding to the left end position of the rack, and Rmax is the angle corresponding to the right end position of the rack. Both Lmax and Rmax must be greater than the total travel of the steering wheel / 2+10°.

[0182] Judgment condition 3: The left end position learning state and the right end position learning state satisfy the following expression:

[0183] CCW_Valid=1&CW_Valid=1

[0184] Among them, CCW_Valid = 1 means that the left end position learning status bit of the rack is valid, and CW_Valid = 1 means that the right end position learning status bit of the rack is valid. & means that both the left end position learning status bit and the right end position learning status bit of the rack are valid.

[0185] Step 6: When the left end position of the rack and the right end position of the rack meet judgment conditions 1 and 3, the vehicle successfully self-learns the rack end position, and the output learning success flag is RackLearnSuccess=1.

[0186] When the left end position of the rack and the right end position of the rack meet judgment conditions 2 and 3, the vehicle fails in self-learning of the rack end position, and the output learning failure flag is RackLearnFail=1.

[0187] Step 7: Determine whether a reset is required. The vehicle determines the current self-learning status and state of the rack end position through the vehicle status information to determine whether a reset is required.

[0188] For example, the vehicle first obtains the status bit of the relevant signal, and then determines whether self-learning fails (status bit is RackLearnFail=1), corner zero point calibration is not completed (status bit is corner zero point calibration status=0), corner zero point routine is completed (status bit is corner zero point routine completion flag bit=1), or the reset button is pressed (status bit is reset button=1). If the above flag bit appears, it is marked as a status reset (status bit is StatusReset=1). If the above status bit does not appear, it is marked as a status not reset (status bit is StatusNotReset=1).

[0189] Then, the vehicle determines whether the left end position learning status is valid and the status is not reset (status bits are CCW_Valid=1 and StatusNotReset=1). If so, the left end position learning is valid (status bit is CCW_Valid_write=1). If not, the left end position learning is invalid (status bit is CCW_Valid_write=0).

[0190] The vehicle can also determine whether the right end position learning status is valid and the status is not reset (status bit is CW_Valid=1 and StatusNotReset=1). If it is true, the right end position learning is valid (status bit is CCW_Valid_write=1). If not, the right end position learning is invalid (status bit is CCW_Valid_write=0).

[0191] The vehicle can also determine whether the learning success flag is set and the status is not reset (status bits are RackLearnSuccess = 1 and StatusNotReset = 1). If true, the end position of the self-learning rack is completed (status bits are Lmax_write = Lmax, Rmax_write = Rmax). If not true, the end position of the self-learning rack is not completed (status bits are Lmax_write = the angle corresponding to the first end position, Rmax_write = the angle corresponding to the second end position).

[0192] The method of the embodiment of the present application is described in detail above, and the device of the embodiment of the present application is provided below.

[0193] See also Figure 8 , Figure 8 80 is a functional unit block diagram of a device for determining the end position of a steering wheel rack provided in an embodiment of the present application. The device for determining the end position of a steering wheel rack 80 may include a processing unit 801 and a communication unit 802. The device for determining the end position of a steering wheel rack 80 is used to implement the aforementioned method for determining the end position of a steering wheel rack, for example Figure 2 The method for determining the end position of the steering wheel rack is shown.

[0194] It should be noted that the division of the above-mentioned multiple units is only a logical division based on functions, and does not limit the specific structure of the device for determining the end position of the steering wheel rack 80. In a specific implementation, some functional modules may be subdivided into more small functional modules, and some functional modules may be combined into one functional module.

[0195] In a possible implementation, the communication unit 802 is used to obtain a first angle of the steering wheel corresponding to a first position of the rack and a second angle of the steering wheel corresponding to a second position, wherein a distance between the first position and a first end position of the rack is less than or equal to a first preset distance, a distance between the second position and a second end position of the rack is less than or equal to a second preset distance, and the first end position and the second end position are preset end positions corresponding to the rack respectively;

[0196] The communication unit 802 is also used to obtain the actual steering angle of the steering wheel;

[0197] Processing unit 801 is used to determine the first target position and the second target position according to the actual steering wheel angle, the first angle and the second angle, wherein the actual steering wheel angle is used to drive the rack to move, and the first target position and the second target position are the actual end positions corresponding to the rack respectively.

[0198] In a possible implementation manner, the processing unit 801 is specifically configured to determine the first target position and the second target position according to the actual steering wheel angle, the first angle, and the second angle, and further include:

[0199] The assist torque of the electric power steering system is controlled according to the first target position and the second target position.

[0200] In a possible implementation, the actual turning angle of the steering wheel includes a first turning angle and a second turning angle, and the processing unit 801 is specifically configured to determine the first target position and the second target position according to the actual turning angle of the steering wheel, the first angle, and the second angle, including:

[0201] The direction corresponding to the first corner is consistent with the direction corresponding to the first angle, and the direction corresponding to the second corner is consistent with the direction corresponding to the second angle;

[0202] When the first rotation angle is greater than the first angle, determining the first target position according to the first rotation angle;

[0203] When the second rotation angle is greater than the second angle, the second target position is determined according to the second rotation angle.

[0204] In a possible implementation, the processing unit 801 is specifically configured to determine the first target position according to the first rotation angle, including:

[0205] Determine a first deviation and a first total stroke according to the first rotation angle and the second angle, wherein the first deviation is used to represent the offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position, and the first total stroke is used to represent the total stroke of the steering wheel;

[0206] When the first deviation is smaller than the first threshold and the first total stroke is smaller than the total stroke threshold, the rack position corresponding to the first rotation angle is used as the first target position.

[0207] In a possible implementation, the processing unit 801 is specifically configured to determine the first target position according to the first rotation angle, including:

[0208] Acquire a first torque of the steering wheel and a first rotation speed of the steering wheel through the communication unit 802, wherein the first torque of the steering wheel and the first rotation speed of the steering wheel correspond to a first angle of the steering wheel;

[0209] When the first torque is greater than the torque threshold and the first rotation speed is less than the rotation speed threshold, the first target position is determined according to the first rotation angle.

[0210] In a possible implementation manner, the processing unit 801 is specifically configured to determine the second target position according to the second rotation angle, including:

[0211] determining a second deviation and a second total stroke according to the second rotation angle and the first angle, wherein the second deviation is used to represent the offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position, and the second total stroke is used to represent the total stroke of the steering wheel;

[0212] When the second deviation is smaller than the second threshold and the second total stroke is smaller than the total stroke threshold, the rack position corresponding to the second rotation angle is used as the second target position.

[0213] In a possible implementation manner, the processing unit 801 is specifically configured to determine the second target position according to the second rotation angle, including:

[0214] Acquire a second torque of the steering wheel and a second rotation speed of the steering wheel through the communication unit 802, wherein the second torque of the steering wheel and the second rotation speed of the steering wheel correspond to a second angle of the steering wheel;

[0215] When the second torque is greater than the torque threshold and the second rotation speed is less than the rotation speed threshold, the second target position is determined according to the second rotation angle.

[0216] In one possible implementation, the difference between the angle corresponding to the first target position and the angle corresponding to the second target position is less than or equal to a third threshold, wherein the third threshold is used to represent the maximum offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position.

[0217] In a possible implementation manner, the first position is determined according to the difference between the distance corresponding to the first end position and the first preset distance;

[0218] The second position is determined based on the difference between the distance corresponding to the second end position and the second preset distance.

[0219] It should be noted that in the embodiments of the present application, the specific implementation and technical effects of each unit can also refer to Figure 2 The corresponding description of the method embodiment shown in .

[0220] See also Fig. 9 , Fig. 9 Schematic diagram of a computing device provided in an embodiment of the present application. Fig. 9 As shown, the computing device 90 may include: one or more processors 901, one or more memories 902, and one or more communication interfaces 903. These components may be connected via a bus 904 or other means. Fig. 9 Take the connection via bus 904 as an example.

[0221] The communication interface 903 may be used for the computing device 90 to communicate with other communication devices, such as other computing devices. Specifically, the communication interface 903 may be a wired interface.

[0222] The memory 902 can be coupled to the processor 901 through the bus 904 or the input and output ports, and the memory 902 can also be integrated with the processor 901. The memory 902 is used to store various software programs and / or multiple sets of instructions or data. Specifically, the memory 902 can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 902 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more disk storage devices, flash memory devices or other non-volatile solid-state storage devices. The memory 902 may store an operating system (hereinafter referred to as system), such as an embedded operating system such as uCOS, VxWorks, RTLinux, etc. The memory 902 may also store a network communication program, which may be used to communicate with one or more additional devices, one or more user devices, or one or more terminals. The memory 902 may be independent and connected to the processor 901 via a bus 904. The memory 902 may also be integrated with the processor 901.

[0223] The memory 902 is used to store application code for executing the above solution, and the execution is controlled by the processor 901. The processor 901 is used to execute the application code stored in the memory 902.

[0224] Processor 901 may be a central processing unit, a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of the present invention. Processor 901 may also be a combination that implements a certain function, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, and the like.

[0225] It should be noted that in the embodiments of the present application, the specific implementation and technical effects of each unit can also refer to Figure 2 The corresponding description of the method embodiment shown in .

[0226] The present application also provides a device for determining the end position of a steering wheel rack, the device comprising a processor and a memory, the processor is coupled to the memory, the memory is used to store a computer program, the processor is used to call and run the computer program, so that the vehicle executes the above-mentioned method for determining the end position of the steering wheel rack, for example Figure 2 method.

[0227] The present application also provides a vehicle, including a steering device and a device for determining the end position of a steering wheel rack.

[0228] The present application also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on at least one processor, the aforementioned method for determining the end position of the steering wheel rack is implemented, for example Figure 2 method.

[0229] The present application also provides a computer program product, which includes computer instructions, and when executed by a computing device, implements the above-mentioned method for determining the end position of the steering wheel rack, for example Figure 2 method.

[0230] In the embodiments of the present application, the words "for example" or "such as" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "for example" or "such as" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the words "for example" or "such as" is intended to present related concepts in a specific way.

[0231] The "at least one" mentioned in the embodiments of the present application refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can be represented by: a, b, c, (a and b), (a and c), (b and c), or (a and b and c), where a, b, c can be single or multiple. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can be represented by: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0232] Furthermore, unless otherwise specified, the ordinal numbers such as "first" and "second" used in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects. For example, the first device and the second device are only for the convenience of description, and do not represent the difference in structure, importance, etc. between the first device and the second device. In some embodiments, the first device and the second device can also be the same device.

[0233] In the above embodiments, the term "when..." can be interpreted as meaning "if..." or "after..." or "in response to determining..." or "in response to detecting...", depending on the context. The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the concept and principle of the present application shall be included in the protection scope of the present application.

[0234] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0235] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining the end position of a steering wheel rack, characterized in that: The method comprises: Acquire a first angle of the steering wheel corresponding to a first position of the rack and a second angle of the steering wheel corresponding to a second position, wherein the distance between the first position and a first end position of the rack is less than or equal to a first preset distance, the distance between the second position and a second end position of the rack is less than or equal to a second preset distance, and the first end position and the second end position are preset end positions corresponding to the rack respectively; Obtaining an actual turning angle of the steering wheel; The first target position and the second target position are determined according to the actual angle of the steering wheel, the first angle and the second angle, wherein the actual angle of the steering wheel is used to drive the rack to move, and the first target position and the second target position are the actual end positions corresponding to the rack respectively.

2. The method according to claim 1, characterized in that After determining the first target position and the second target position according to the actual rotation angle of the steering wheel, the first angle and the second angle, the method further includes: The assist torque of the electric power steering system is controlled according to the first target position and the second target position.

3. The method according to claim 1 or 2, characterized in that: The actual rotation angle of the steering wheel includes a first rotation angle and a second rotation angle, and determining the first target position and the second target position according to the actual rotation angle of the steering wheel, the first angle and the second angle includes: The direction corresponding to the first angle is consistent with the direction corresponding to the first angle, and the direction corresponding to the second angle is consistent with the direction corresponding to the second angle; When the first rotation angle is greater than the first angle, determining the first target position according to the first rotation angle; When the second rotation angle is greater than the second angle, the second target position is determined according to the second rotation angle.

4. The method according to claim 3, characterized in that The determining the first target position according to the first rotation angle includes: determining a first deviation and a first total stroke according to the first rotation angle and the second angle, wherein the first deviation is used to represent an offset of a corresponding rack center relative to a midpoint of the rack when the steering wheel is at a zero position, and the first total stroke is used to represent a total stroke of the steering wheel; When the first deviation is smaller than a first threshold and the first total stroke is smaller than a total stroke threshold, the rack position corresponding to the first rotation angle is used as the first target position.

5. The method according to claim 3 or 4, characterized in that: The determining the first target position according to the first rotation angle includes: Acquire a first torque of the steering wheel and a first rotation speed of the steering wheel, wherein the first torque of the steering wheel and the first rotation speed of the steering wheel correspond to a first rotation angle of the steering wheel; When the first torque is greater than a torque threshold and the first rotation speed is less than a rotation speed threshold, the first target position is determined according to the first rotation angle.

6. The method according to claim 4 or 5, characterized in that: The determining the second target position according to the second rotation angle comprises: determining a second deviation and a second total stroke according to the second rotation angle and the first angle, wherein the second deviation is used to represent the offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position, and the second total stroke is used to represent the total stroke of the steering wheel; When the second deviation is smaller than a second threshold and the second total stroke is smaller than the total stroke threshold, the rack position corresponding to the second rotation angle is used as the second target position.

7. The method according to claim 5 or 6, characterized in that: The determining the second target position according to the second rotation angle comprises: Acquire a second torque of the steering wheel and a second rotation speed of the steering wheel, wherein the second torque of the steering wheel and the second rotation speed of the steering wheel correspond to a second angle of the steering wheel; When the second torque is greater than the torque threshold and the second rotation speed is less than the rotation speed threshold, a second target position is determined according to the second rotation angle.

8. The method according to any one of claims 1 to 7, characterized in that: The difference between the angle corresponding to the first target position and the angle corresponding to the second target position is less than or equal to a third threshold, wherein the third threshold is used to represent the maximum offset of the corresponding rack center relative to the midpoint of the rack when the steering wheel is at the zero position.

9. The method according to any one of claims 1 to 8, characterized in that: The first position is determined according to the difference between the distance corresponding to the first end position and the first preset distance; The second position is determined according to the difference between the distance corresponding to the second end position and the second preset distance.

10. A device for determining the end position of a steering wheel rack, characterized in that: The device includes a processor and a memory, wherein the processor is coupled to the memory, the memory is used to store a computer program, and the processor is used to call and run the computer program so that the vehicle executes the method according to any one of claims 1 to 9.

11. A vehicle, characterized in that: The invention comprises a steering system and a device for determining the end position of a steering wheel rack as claimed in claim 10.

12. A computing device, characterized in that: The method comprises a processor coupled to a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program, so that the computing device executes the method according to any one of claims 1 to 9.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program includes instructions for executing the method according to any one of claims 1 to 9.

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