Rack calibration method and device of steer-by-wire system and electronic equipment

Abstract

The invention discloses a rack calibration method and device of a steer-by-wire system and electronic equipment, the rack calibration method of the steer-by-wire system can be applied to the technical field of automobile steering, and the method comprises the steps that the actual rack neutral position of a target vehicle when the target vehicle is in a straight moving state in the current period is obtained; the difference value between the actual rack middle position and the calibrated rack middle position is determined, and rack middle position deviation is obtained; calibrating a rack neutral position as a rack neutral position acquired when the target vehicle is in a straight running state under an ideal condition; based on at least one of the rack median deviation and the confidence coefficient of the rack tail end position of the previous period, whether the rack tail end position of the previous period is valid or not is judged; under the condition that the tail end position of the rack in the previous period is invalid, the tail end position of the rack in the current period is determined based on the deviation of the rack design stroke and the rack neutral position; and determining the confidence coefficient of the end position of the rack in the current period based on the rack median deviation. Symmetry of the left stroke and the right stroke of the rack is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of automobile steering technology, and in particular to a rack calibration method, device and electronic equipment for a wire-controlled steering system. Background Art

[0002] Steering-By-Wire (SBW) is a new steering system. Figure 1 As shown in the figure, the mechanical connection parts between the traditional steering wheel assembly and the wheel actuator are replaced by electronic and software technology, which completely gets rid of the limitations of mechanical firmware, realizes the decoupling between the steering wheel assembly and the wheel actuator, and completely relies on electrical energy to achieve steering control. The SBW system not only improves the flexibility and precision of steering, but also enhances the safety and comfort of the system.

[0003] When designing a steer-by-wire system, the maximum rack travel and the corresponding maximum steering angles at the left and right ends are predefined. The end position of the rack is called the mechanical hard stop of the rack. At present, the accuracy of these mechanical hard stops is mainly ensured by tooling during precision machining.

[0004] However, in actual use scenarios, due to assembly errors (such as left-right symmetry errors when installing the steering system on the OEM production line) and the influence of bad driving conditions, the steering actuator may be offset from the center position, resulting in asymmetric distances between the left and right hard stops of the steering actuator relative to the driving center position. This asymmetry will cause inconsistency in the left and right extreme travels of the steering wheel, thus affecting the customer's driving experience. Summary of the invention

[0005] In order to solve the problems of the prior art, the embodiments of the present application provide a rack calibration method, device and electronic device for a wire-controlled steering system. The technical solution is as follows:

[0006] In one aspect, a rack calibration method for a steer-by-wire system is provided, the method comprising:

[0007] Acquire the actual rack center position of the current cycle; the actual rack center position is the rack center position collected when the target vehicle is in a straight-ahead state in the current cycle;

[0008] Determine the difference between the actual rack center position and the calibrated rack center position to obtain the rack center position deviation; the calibrated rack center position is the rack center position collected when the target vehicle is in a straight-ahead state under ideal conditions;

[0009] Based on at least one of the rack median deviation and the confidence of the rack end position in the previous cycle, determining whether the rack end position in the previous cycle is valid;

[0010] In the case where the rack end position of the previous cycle is invalid, determining the rack end position of the current cycle based on the rack design stroke and the rack median deviation;

[0011] The confidence level of the rack end position of the current cycle is determined based on the rack median deviation.

[0012] In another aspect, a rack calibration device for a steer-by-wire system is provided, the device comprising:

[0013] A median position acquisition module, used to acquire an actual rack median position of the current cycle; the actual rack median position is the rack median position acquired when the target vehicle is in a straight-ahead state in the current cycle;

[0014] A median deviation module is used to determine the difference between the actual rack median and the calibrated rack median to obtain the rack median deviation; the calibrated rack median is the rack median collected when the target vehicle is in a straight-ahead state under ideal conditions;

[0015] A validity judgment module, used for judging whether the rack end position of the previous cycle is valid based on at least one of the rack median deviation and the confidence of the rack end position of the previous cycle;

[0016] An end determination module, used to determine the end position of the rack in the current cycle based on the rack design stroke and the rack median deviation when the rack end position of the previous cycle is invalid;

[0017] A confidence determination module is used to determine the confidence of the rack end position in the current cycle based on the rack median deviation.

[0018] In an exemplary embodiment, the end determination module includes:

[0019] A threshold acquisition module, used to acquire a plurality of median deviation thresholds within a stroke difference range; the stroke difference range is determined based on the rack design stroke and the rack mechanical stroke;

[0020] A threshold selection module, used to select a median deviation threshold from the multiple median deviation thresholds; the selected median deviation threshold is smaller than any unselected threshold from the multiple median deviation thresholds;

[0021] a target threshold module, for selecting a median deviation threshold from the remaining median deviation thresholds when the rack median deviation is less than or equal to the selected median deviation threshold, and determining the selected median deviation threshold as the target median deviation threshold when the rack median deviation is greater than the selected median deviation threshold; the remaining median deviation threshold is a threshold value that has not been selected from the multiple median deviation thresholds;

[0022] The stroke calculation module is used to determine the rack end position of the current cycle based on the calculation rule corresponding to the rack design stroke and the target median deviation threshold.

[0023] In an exemplary embodiment, the confidence determination module includes:

[0024] A mapping acquisition module, used to acquire threshold confidence mapping information; the threshold confidence mapping information includes a mapping relationship between each median deviation threshold and the confidence of the rack end position; the median deviation threshold is negatively correlated with the confidence of the rack end position;

[0025] The target confidence module is used to determine the confidence corresponding to the target median deviation threshold in the threshold confidence mapping information, and obtain the confidence of the rack end position in the current cycle.

[0026] In an exemplary embodiment, the validity determination module includes:

[0027] A critical threshold module, used to select a critical median deviation threshold from the multiple median deviation thresholds; the critical median deviation threshold is greater than any unselected threshold from the multiple median deviation thresholds;

[0028] A confidence threshold module, used to determine the confidence corresponding to the critical median deviation threshold in the threshold confidence mapping information to obtain a confidence threshold;

[0029] The first valid module is used to determine that the rack end position in the previous cycle is valid when the confidence of the rack end position in the previous cycle is greater than the confidence threshold.

[0030] In an exemplary embodiment, the validity determination module includes:

[0031] A history acquisition module is used to obtain the rack median deviation of the historical period;

[0032] A median evaluation module, used for evaluating whether the rack median deviation is always credible based on the rack median deviation of the historical cycle and the rack median deviation of the current cycle;

[0033] The second valid module is used to determine that the rack end position of the previous cycle is valid when the rack center deviation is always credible.

[0034] In an exemplary embodiment, the device further comprises a position inheritance module for inheriting the rack end position of the previous cycle in the current cycle when the rack end position of the previous cycle is valid, and the position inheritance module comprises:

[0035] The position inheritance module is used to determine the rack end position of the previous cycle as the rack end position of the current cycle.

[0036] In an exemplary embodiment, the device further includes a median invalid module, the median invalid module including:

[0037] The center position invalid module is used to use the calibrated rack center position as the actual rack center position when the actual rack center position is invalid.

[0038] On the other hand, an electronic device is provided, comprising a processor and a memory, wherein the memory stores at least one instruction or at least one program, and the at least one instruction or the at least one program is loaded and executed by the processor to implement the rack calibration method of the wire-controlled steering system of any of the above aspects.

[0039] On the other hand, a computer-readable storage medium is provided, in which at least one instruction or at least one program is stored, and the at least one instruction or the at least one program is loaded and executed by a processor to implement the rack calibration method of a wire-controlled steering system as described in any of the above aspects.

[0040] On the other hand, a computer program product or a computer program is provided, the computer program product or the computer program comprising computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device performs the rack calibration method of a wire-controlled steering system according to any one of the above aspects.

[0041] The embodiment of the present application calculates the difference between the actual rack median and the rack median calibrated under ideal conditions to obtain the rack median deviation; then based on at least one of the rack median deviation and the confidence of the rack end position in the previous cycle, it is determined whether the rack end position in the previous cycle is valid; if the rack end position in the previous cycle is invalid, the rack end position in the current cycle is determined based on the rack design stroke and the rack median deviation, and the confidence of the rack end position in the current cycle is further determined based on the rack median deviation. Taking the rack median deviation into account, the rack end position is accurately calculated and adjusted in real time, ensuring the symmetry of the left and right travels of the rack, and then ensuring the symmetry of the left and right extreme angles of the steering wheel, improving the reliability and accuracy of the steering system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 is a structural schematic diagram of a wire-controlled steering system provided in an embodiment of the present application;

[0044] Figure 2 It is a flow chart of a rack calibration method of a wire-controlled steering system provided in an embodiment of the present application;

[0045] Figure 3 is a flow chart of another rack calibration method of a wire-controlled steering system provided in an embodiment of the present application;

[0046] Figure 4 is a flow chart of a method for updating the rack end position provided in an embodiment of the present application;

[0047] Figure 5 is a rack end position distribution diagram corresponding to different working conditions provided in the embodiment of the present application;

[0048] Figure 6 is a structural block diagram of a rack calibration device for a wire-controlled steering system provided in an embodiment of the present application;

[0049] Figure 7 It is a hardware structure block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0052] It is understandable that in the specific implementation of this application, related data such as user information is involved. When the above embodiments of this application are applied to specific products or technologies, user permission or consent is required, and the collection, use and processing of relevant data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0053] In the actual use scenario of the wire control steering system, due to assembly errors (such as the left-right symmetry error when installing the steering system on the OEM production line) and the influence of bad driving conditions, the steering actuator may be offset from the center position, resulting in the asymmetry of the left and right hard stop distances of the steering actuator relative to the driving center position. This asymmetry phenomenon will cause the left and right extreme travel of the steering wheel to be inconsistent, thus affecting the customer's driving experience.

[0054] In view of this, an embodiment of the present application provides a rack calibration method for a wire-controlled steering system, such as Figure 2 As shown, it mainly includes the following steps:

[0055] Step 1: The wheel actuator controller receives a calibrated rack center position signal and an actual rack center position signal from a private CAN network; the calibrated rack center position signal is the rack center position value obtained during four-wheel alignment on the production line; the actual rack center position signal is the real-time rack position collected when the vehicle is in a straight-ahead state;

[0056] Step 2: When the wheel actuator controller receives the KL15 signal as ON, it enters the controller initialization process. After the initialization is completed, the rack center deviation is calculated based on the calibrated rack center signal and the actual rack center signal;

[0057] Step 3, check whether the rack end position of the previous cycle is valid, if not, go to step 4, if valid, go to step 5;

[0058] Step 4, perform rack end position update calculation and end;

[0059] Step 5: The current cycle inherits the rack end position of the previous calculation cycle and ends.

[0060] See also Figure 3 , which shows a flow chart of another rack calibration method for a wire-controlled steering system provided in an embodiment of the present application. It should be noted that this specification provides method operation steps such as the embodiments or flow charts, but may include more or fewer operation steps based on conventional or non-creative labor. The sequence of steps listed in the embodiments is only one way of executing the steps among many sequences, and does not represent the only execution sequence. When the system or product is executed in practice, it can be executed in the sequence of the methods shown in the embodiments or the drawings, or in parallel (for example, in a parallel processor or multi-threaded processing environment). Specifically, Figure 3 As shown, the method may include:

[0061] S301, obtaining the actual rack center position of the current cycle.

[0062] The current cycle refers to the time interval or cycle for calculating the rack end position.

[0063] The actual rack center position is the rack center position collected when the target vehicle is in a straight-ahead state in the current cycle.

[0064] The target vehicle refers to a specific vehicle that needs to be calibrated for the rack.

[0065] The straight-ahead state refers to a state in which the target vehicle has a steering wheel in a centered position without any steering action.

[0066] Specifically, when the target vehicle is in a straight-ahead state in the current cycle, the rack center position at this time is collected to obtain the actual rack center position. If the target vehicle is not in a straight-ahead state in the current cycle, the actual rack center position of the previous cycle can be used as the actual rack center position of the current cycle to calculate the subsequent rack end position.

[0067] Specifically, in each calculation cycle, the rack center position when the target vehicle is in a straight-ahead state is obtained in real time. In a specific implementation, the position information of the rack when the vehicle is in a straight-ahead state in the current cycle is monitored and recorded in real time by a sensor (such as a position sensor).

[0068] S303, determining the difference between the actual rack center position and the calibrated rack center position to obtain the rack center position deviation.

[0069] The calibrated rack center position is the rack center position collected when the target vehicle is in a straight-ahead state under ideal conditions. In specific implementation, the calibrated rack center position refers to the rack center value collected when the target vehicle is aligned on the production line. The rack center value is usually calibrated by special equipment before the target vehicle leaves the factory and stored in the control system of the target vehicle as a reference value for subsequent calculations.

[0070] Among them, the ideal condition means that the target vehicle has no interference factors, such as assembly errors and uneven road surfaces.

[0071] The rack median deviation reflects the difference between the current rack median and the ideal state. By calculating the rack median deviation, the deviation of the current rack position from the ideal position can be evaluated and adjusted accordingly.

[0072] In an exemplary embodiment, when the actual rack center position is invalid, the calibrated rack center position is used as the actual rack center position.

[0073] Specifically, the specific method for calculating the rack median deviation value is: rack median deviation = software straight-ahead median - rack absolute median; among them, the specific method for calculating the software straight-ahead median value is: when the actual rack median is valid, the software straight-ahead median value = actual rack median, otherwise, the software straight-ahead median value = calibrated rack median; the specific method for calculating the rack absolute median is: rack absolute median = calibrated rack median.

[0074] In specific implementation, whether the actual rack center position is valid can be determined by the following methods:

[0075] Data consistency check. Compare with historical data to check whether the actual rack center position of the current cycle is consistent with the data in the most recent period. If there is a sudden change or jump, it may be invalid. Compare with other sensor data, for example, check whether the actual rack center position matches the data of the steering wheel angle sensor. If the vehicle is in a straight state, the steering wheel should be centered in theory. If the actual rack center position shows that the vehicle is not in a straight state, the signal may be invalid.

[0076] Data rationality verification. Value range check to ensure that the actual rack center position falls within a reasonable value range. If it exceeds the preset reasonable range, the signal may be invalid. Logical consistency, combined with the vehicle's current driving status (such as speed, turn signal status, etc.) to determine whether the actual rack center position is reasonable. For example, when driving at high speed and without a turn signal, if the actual rack center position shows that the vehicle deviates from the straight line, the signal may be invalid.

[0077] Signal quality detection. Check the signal strength to ensure that the actual rack center position signal is not disturbed or lost during transmission. Check the signal frequency to check whether the actual rack center position signal update frequency meets the requirements. If the signal is not updated in time, it may be invalid.

[0078] Fault diagnosis. Self-diagnosis function. The system may have a self-diagnosis module to detect the working status of the sensor. If the diagnosis result shows that the sensor used to detect the actual rack center position is faulty, the actual rack center position may be invalid. Redundant system comparison. If there are redundant sensors or data sources, the validity of the actual rack center position can be determined by comparing the data between them.

[0079] Environmental factors. Consider environmental influences. For example, if the vehicle is driving on a bumpy road, it may cause sensor readings to fluctuate, and interference factors need to be eliminated.

[0080] In actual applications, the above methods may be used in combination to comprehensively judge the effectiveness of the actual rack center position through multi-dimensional data analysis. For example, if the signal has an abnormally large fluctuation in a short period of time, or is inconsistent with the data of other related sensors, then the signal is considered invalid. On the contrary, if the signal is stable and consistent with the data of other sensors, the signal is considered valid.

[0081] It can be seen from the above technical solutions of the embodiments of the present application that when the actual rack center position signal cannot be used, the embodiments of the present application use the calibrated rack center position as a reference by default. At this time, it is assumed that the rack center position of the target vehicle in a straight-ahead state is the pre-calibrated rack position, so that when the actual rack center position signal of the target vehicle is lost, the normal operation of the rack calibration program is still maintained.

[0082] S305: Based on at least one of the rack median deviation and the confidence of the rack end position in the previous cycle, determine whether the rack end position in the previous cycle is valid.

[0083] Specifically, if the result of the judgment is no, step S307 can be executed; otherwise, if the result of the judgment is yes, step S3011 can be executed.

[0084] The rack end position refers to the maximum position to which the rack can move, that is, the extreme position of the rack, including the left rack end position and the right rack end position.

[0085] The confidence level refers to the degree of trust in the rack end position in the previous cycle.

[0086] For example, if the rack center deviation is not credible, or the rack end position confidence level in the previous cycle is low, the rack end position in the previous cycle may be invalid.

[0087] Specifically, when the rack end position of the previous cycle is valid, the current cycle inherits the rack end position of the previous cycle; when the rack end position of the previous cycle is invalid, the rack end position of the current cycle is recalculated.

[0088] In an exemplary implementation, the above step S305 may include the following steps:

[0089] A plurality of median deviation thresholds within the range of the travel difference are obtained, and a critical median deviation threshold is selected from the plurality of median deviation thresholds; the critical median deviation threshold is greater than any unselected threshold from the plurality of median deviation thresholds.

[0090] The travel difference range is determined based on the design travel of the rack and the mechanical travel of the rack, that is, the difference between the maximum movement range allowed by the rack during design and the maximum movement range that can be achieved in actual use.

[0091] Specifically, the stroke difference is calculated, and the stroke difference = (rack mechanical stroke - rack design stroke) / 2; the stroke difference range is [0, stroke difference], and then, within the stroke difference range, a suitable median deviation threshold is selected through a calibration method, and more than one median deviation threshold can be selected within the difference range.

[0092] The median deviation threshold refers to a series of values ​​used to determine whether the rack median deviation exceeds a normal range.

[0093] In specific implementations, these median deviation thresholds are usually determined through experimental data and historical records, and are intended to cover possible deviations of the rack under different conditions. For example, multiple median deviation thresholds are set according to different usage environments (such as different road conditions, different vehicle loads, etc.) to ensure that the rack median deviation can be accurately judged under various conditions.

[0094] For example, if the rack design stroke is 100mm and the rack mechanical stroke is 95mm, the stroke difference range is 5mm. Multiple median deviation thresholds are set within this range, such as 1mm, 2mm, and 3mm. Among them, 3mm is the critical median deviation threshold, and other median deviation thresholds are less than 3mm.

[0095] The threshold confidence mapping information is obtained, and the confidence corresponding to the critical median deviation threshold is determined in the threshold confidence mapping information to obtain the confidence threshold.

[0096] The threshold confidence mapping information includes a mapping relationship between each median deviation threshold and the confidence of the rack end position; the median deviation threshold is negatively correlated with the confidence of the rack end position.

[0097] Assume that the data contained in the threshold confidence mapping information is: 1mm->0.9, 2mm->0.8, 3mm->0.7. Here, the confidence corresponding to 3mm is 0.7. If the critical median deviation threshold is 3mm, the corresponding confidence threshold is 0.7.

[0098] In a specific implementation, the confidence level corresponding to the critical median deviation threshold is usually set to 0.

[0099] When the confidence of the rack end position in the previous cycle is greater than the confidence threshold, the rack end position in the previous cycle is determined to be valid; when the confidence of the rack end position in the previous cycle is less than or equal to the confidence threshold, the rack end position in the previous cycle is determined to be invalid.

[0100] It can be seen from the above technical solutions of the embodiment of the present application that the embodiment of the present application dynamically evaluates the validity of the rack end position data, sets a reasonable median deviation threshold and a corresponding confidence threshold, and ensures that the rack end position of the previous cycle is inherited only when the rack end position of the previous cycle is credible, otherwise the rack end position of the current cycle is recalculated, thereby improving the stability and reliability of the wire-controlled steering system.

[0101] In an exemplary implementation, the above step S305 may include the following steps:

[0102] Get the rack median deviation of the historical cycle, that is, the historical data of the rack median deviation recorded before the current cycle;

[0103] Based on the rack median deviation of the historical cycle and the rack median deviation of the current cycle, evaluate whether the rack median deviation is always reliable; the rack median deviation is always reliable means that within a certain period of time (i.e., from the historical cycle to the current cycle), the change of the rack median deviation is continuous and stable, without abnormal fluctuations;

[0104] In the case where the rack center deviation is always credible, the rack end position of the previous cycle is determined to be valid.

[0105] In specific implementations, the rack median deviation of historical periods can be obtained from a database, log file or other storage system, and data from the most recent periods are usually selected as a reference to ensure the timeliness and accuracy of the evaluation.

[0106] In specific implementation, the change trend of the rack median deviation in the historical period and the current period can be calculated to check whether there is a sudden large fluctuation. For example, the rate of change of the rack median deviation can be calculated, or the average and standard deviation of the rack median deviation in the historical period and the current period can be compared.

[0107] In a specific implementation, the evaluation standard may be a preset range or threshold. If the change is within the acceptable range, the rack median deviation is considered to be credible.

[0108] If the rack median deviation is found to be reliable during the entire observation period, the rack end position of the previous cycle can be considered valid, and the rack end position does not need to be recalculated in the current cycle, and the rack end position of the previous cycle is inherited. Otherwise, the rack end position of the current cycle needs to be recalculated.

[0109] It can be seen from the above technical solutions of the embodiment of the present application that the embodiment of the present application evaluates the credibility of the rack median deviation through the rack median deviation data of the historical cycle and the current cycle, and determines whether the rack end position of the previous cycle is valid based on this, which helps to ensure the accuracy and reliability of the rack calibration, and further ensures that the rack end position of the previous cycle is inherited only when the rack end position of the previous cycle is credible, otherwise the rack end position of the current cycle is recalculated, thereby improving the stability and reliability of the wire-controlled steering system.

[0110] S307, determining the rack end position of the current cycle based on the rack design stroke and the rack mid-position deviation.

[0111] The rack design stroke refers to the maximum range of movement allowed by the rack during design.

[0112] Specifically, if the rack end position of the previous cycle is judged to be invalid, the rack end position of the current cycle is re-determined. Specifically, based on the rack design stroke and the rack median deviation value calculated in the current cycle, the extreme positions of the rack in the current cycle, i.e., the left rack end position and the right rack end position, are calculated.

[0113] In an exemplary embodiment, Figure 4 As shown, the above step S307 may include:

[0114] S401, obtaining multiple median deviation thresholds within a travel difference range.

[0115] The travel difference range is determined based on the design travel of the rack and the mechanical travel of the rack, that is, the difference between the maximum movement range allowed by the rack during design and the maximum movement range that can be achieved in actual use.

[0116] Among them, the rack design stroke refers to the maximum movement range of the rack determined in the design stage, and the rack design stroke is smaller than the rack mechanical stroke.

[0117] Among them, the mechanical travel of the rack refers to the maximum movement range that the rack can achieve in actual use.

[0118] Specifically, the stroke difference is calculated, and the stroke difference = (rack mechanical stroke - rack design stroke) / 2; the stroke difference range is [0, stroke difference], and then, within the stroke difference range, a suitable median deviation threshold is selected through a calibration method, and more than one median deviation threshold can be selected within the difference range.

[0119] The median deviation threshold refers to a series of values ​​used to determine whether the rack median deviation exceeds a normal range.

[0120] In specific implementations, these median deviation thresholds are usually determined through experimental data and historical records, and are intended to cover possible deviations of the rack under different conditions. For example, multiple median deviation thresholds are set according to different usage environments (such as different road conditions, different vehicle loads, etc.) to ensure that the rack median deviation can be accurately judged under various conditions.

[0121] S403: Select a median deviation threshold from multiple median deviation thresholds.

[0122] The selected median deviation threshold is smaller than any unselected threshold among the multiple median deviation thresholds.

[0123] Specifically, a minimum median deviation threshold is selected from multiple median deviation thresholds as a reference value. Selecting the minimum median deviation threshold can ensure greater sensitivity in determining the rack median deviation, thereby timely discovering and correcting possible deviations, which helps to improve the accuracy and response speed of rack calibration.

[0124] S405, determining whether the rack median deviation is greater than a selected median deviation threshold.

[0125] Specifically, if the result of the judgment is no, step S407 can be executed; otherwise, if the result of the judgment is yes, step S409 can be executed.

[0126] S407, selecting a median deviation threshold from the remaining median deviation thresholds.

[0127] Specifically, continue to execute step S405.

[0128] The remaining median deviation threshold is a threshold that is not selected among the multiple median deviation thresholds.

[0129] Specifically, when the rack median deviation is less than or equal to the selected median deviation threshold, the median deviation threshold is selected from the remaining median deviation thresholds. This process will continue until the rack median deviation is greater than the selected median deviation threshold, and the selection of the median deviation threshold is terminated.

[0130] Specifically, compare the absolute value of the rack median deviation value and the median deviation threshold. When there are multiple median deviation thresholds, compare them with the absolute value of the rack median deviation one by one in ascending order of the median deviation threshold. Once it is found that the absolute value of the rack median deviation is less than a certain median deviation threshold, it will no longer be compared with a larger median deviation threshold.

[0131] S409: Determine the selected median deviation threshold as the target median deviation threshold.

[0132] The target median deviation threshold refers to the median deviation threshold finally determined for judging the rack median deviation. Specifically, when the rack median deviation is greater than the selected median deviation threshold, the selected median deviation threshold is determined as the target median deviation threshold.

[0133] S4011, based on the calculation rules corresponding to the rack design stroke and the target median deviation threshold, determine the rack end position of the current cycle.

[0134] Specifically, Figure 5 As shown, when the absolute value of the rack median deviation does not exceed the critical median deviation threshold, that is, the largest median deviation threshold among multiple median deviation thresholds (threshold 2 shown in the figure), the rack median deviation can be ignored, and the left rack end position is set to (-1 / 2*rack design stroke L), and the right rack end position is set to (+1 / 2*rack design stroke L). When the absolute value of the rack median deviation exceeds the critical median deviation threshold, the left rack end position is set to (-1 / 2*rack design stroke L-rack median deviation δ), and the right rack end position is set to (+1 / 2*rack design stroke L-rack median deviation δ).

[0135] It can be seen from the above technical solutions of the embodiment of the present application that the embodiment of the present application dynamically adjusts the rack end position by comparing the rack median deviation with multiple median deviation thresholds step by step. When the rack median deviation value is within a reasonable range, the rack median deviation can be ignored to keep the left and right rack end positions symmetrical; when the rack median deviation value exceeds the maximum threshold, the left and right rack end positions are adjusted according to the rack median deviation, thereby ensuring the accuracy and reliability of the wire-controlled steering system, improving the rack calibration sensitivity and response speed, and enhancing the accuracy and stability of the wire-controlled steering system.

[0136] S309, determining the confidence of the rack end position in the current cycle based on the rack median deviation.

[0137] The confidence level refers to the degree of trust in the rack end position calculated in the current cycle.

[0138] Specifically, the confidence of the rack end position in the current cycle is determined according to the rack median deviation value calculated in the current cycle, so as to determine whether the rack end position needs to be recalculated in the next cycle. Specifically, if the rack median deviation is small, it indicates that the current rack position is closer to the ideal position, and the confidence of the rack end position in the current cycle is high.

[0139] In an exemplary implementation, the above step S309 may include the following steps:

[0140] Acquire threshold confidence mapping information; the threshold confidence mapping information includes a mapping relationship between each median deviation threshold and the confidence of the rack end position; the median deviation threshold is negatively correlated with the confidence of the rack end position;

[0141] The confidence corresponding to the target median deviation threshold is determined in the threshold confidence mapping information to obtain the confidence of the rack end position in the current cycle.

[0142] Specifically, the threshold confidence mapping information indicates that the larger the median deviation threshold, the lower the confidence of the rack end position. A larger median deviation threshold means that a larger deviation range is allowed, which generally reflects an increase in uncertainty about the current rack position. For example, threshold 1 is less than threshold 2, the confidence corresponding to threshold 1 is 0.9, the confidence corresponding to threshold 2 is 0.8, and so on. The threshold confidence mapping information can be presented in a table to facilitate system access and use. In a specific implementation, the threshold confidence mapping information can be pre-defined in the system configuration file or obtained through historical data statistics. Specifically, during the system development phase, engineers will define a series of median deviation thresholds based on experience and test data, and assign a corresponding confidence value to each threshold. Alternatively, during the actual operation of the system, through long-term data accumulation and analysis, these mapping relationships can be continuously optimized to make them more accurate and reliable.

[0143] For example, Figure 5 As shown, the median deviation thresholds are 0, threshold 1, and threshold 2, respectively; where 0 is less than threshold 1 and less than threshold 2. The confidence corresponding to 0 is 2, the confidence corresponding to threshold 1 is 1, and the confidence corresponding to threshold 2 is 0. When the absolute value of the rack median deviation does not exceed threshold 1, the confidence of the rack end position in the current cycle is 2; when the absolute value of the rack median deviation exceeds threshold 1 but does not exceed threshold 2, the confidence of the rack end position in the current cycle is 1; when the absolute value of the rack median deviation exceeds threshold 2, the confidence of the rack end position in the current cycle is 2.

[0144] It can be seen from the above technical solutions of the embodiment of the present application that the embodiment of the present application determines the confidence of the rack end position of the current cycle through pre-defined threshold confidence mapping information, ensuring that the credibility of the rack position can be accurately judged under various circumstances, thereby improving the accuracy and reliability of the wire-controlled steering system and providing a basis for whether the rack end position needs to be recalculated in the next cycle.

[0145] S3011, determining the rack end position of the previous cycle as the rack end position of the current cycle.

[0146] Specifically, when the rack end position of the previous cycle is valid, the rack end position does not need to be recalculated in the current cycle, and the rack end position of the previous cycle is inherited.

[0147] It can be seen from the above technical scheme of the embodiment of the present application that the embodiment of the present application obtains the rack median deviation by calculating the difference between the actual rack median and the calibrated rack median under ideal conditions; then, based on at least one of the rack median deviation and the confidence of the rack end position in the previous cycle, it is determined whether the rack end position in the previous cycle is valid; if the rack end position in the previous cycle is invalid, the rack end position in the current cycle is determined according to the rack design stroke and the rack median deviation, and the confidence of the rack end position in the current cycle is further determined based on the rack median deviation. Taking the rack median deviation into account, the rack end position is accurately calculated and adjusted in real time, which ensures the symmetry of the left and right travels of the rack, and then ensures the symmetry of the left and right extreme angles of the steering wheel, improving the reliability and accuracy of the wire control steering system.

[0148] Specifically, if the result of the judgment is no, step S303 may be executed; otherwise, if the result of the judgment is yes, step S309 may be executed.

[0149] Corresponding to the rack calibration methods for steer-by-wire systems provided in the above-mentioned embodiments, an embodiment of the present application further provides a rack calibration device for a steer-by-wire system. Since the rack calibration device for a steer-by-wire system provided in the embodiment of the present application corresponds to the rack calibration methods for steer-by-wire systems provided in the above-mentioned embodiments, the implementation methods of the rack calibration methods for steer-by-wire systems are also applicable to the rack calibration device for a steer-by-wire system provided in the present embodiment and are not described in detail in the present embodiment.

[0150] See also Figure 6 , which is a schematic diagram of the structure of a rack calibration device for a wire-controlled steering system provided in an embodiment of the present application, the device has the function of implementing the rack calibration method for a wire-controlled steering system in the above method embodiment, and the function can be implemented by hardware, or by hardware executing corresponding software. Figure 6 As shown, the device may include:

[0151] The median position acquisition module 610 is used to acquire the actual rack median position of the current cycle; the actual rack median position is the rack median position acquired when the target vehicle is in a straight-moving state in the current cycle;

[0152] The median deviation module 620 is used to determine the difference between the actual rack median and the calibrated rack median to obtain the rack median deviation; the calibrated rack median is the rack median collected when the target vehicle is in a straight-ahead state under ideal conditions;

[0153] A validity judgment module 630, configured to judge whether the rack end position in the previous cycle is valid based on at least one of the rack median deviation and the confidence of the rack end position in the previous cycle;

[0154] The end determination module 640 is used to determine the rack end position of the current cycle based on the rack design stroke and the rack median deviation when the rack end position of the previous cycle is invalid;

[0155] The confidence determination module 650 is used to determine the confidence of the rack end position in the current cycle based on the rack median deviation.

[0156] In an exemplary embodiment, the end determination module includes:

[0157] A threshold acquisition module is used to acquire multiple median deviation thresholds within a stroke difference range; the stroke difference range is determined based on the rack design stroke and the rack mechanical stroke;

[0158] A threshold selection module is used to select a median deviation threshold from multiple median deviation thresholds; the selected median deviation threshold is smaller than any unselected threshold from the multiple median deviation thresholds;

[0159] A target threshold module is used to select a median deviation threshold from the remaining median deviation thresholds when the rack median deviation is less than or equal to the selected median deviation threshold, and to determine the selected median deviation threshold as the target median deviation threshold when the rack median deviation is greater than the selected median deviation threshold; the remaining median deviation threshold is a threshold that has not been selected from the multiple median deviation thresholds;

[0160] The stroke calculation module is used to determine the rack end position of the current cycle based on the calculation rules corresponding to the rack design stroke and the target median deviation threshold.

[0161] In an exemplary embodiment, the confidence determination module includes:

[0162] A mapping acquisition module is used to acquire threshold confidence mapping information; the threshold confidence mapping information includes a mapping relationship between each median deviation threshold and the confidence of the rack end position; the median deviation threshold is negatively correlated with the confidence of the rack end position;

[0163] The target confidence module is used to determine the confidence corresponding to the target median deviation threshold in the threshold confidence mapping information, and obtain the confidence of the rack end position in the current cycle.

[0164] In an exemplary embodiment, the validity determination module includes:

[0165] A critical threshold module, used to select a critical median deviation threshold from a plurality of median deviation thresholds; the critical median deviation threshold is greater than any unselected threshold from the plurality of median deviation thresholds;

[0166] A confidence threshold module is used to determine the confidence corresponding to the critical median deviation threshold in the threshold confidence mapping information to obtain a confidence threshold;

[0167] The first valid module is used to determine that the rack end position in the previous cycle is valid when the confidence of the rack end position in the previous cycle is greater than a confidence threshold.

[0168] In an exemplary embodiment, the validity determination module includes:

[0169] A history acquisition module is used to obtain the rack median deviation of the historical period;

[0170] A median evaluation module is used to evaluate whether the rack median deviation is always reliable based on the rack median deviation of the historical period and the rack median deviation of the current period;

[0171] The second valid module is used to determine the validity of the rack end position in the previous cycle when the rack center deviation is always credible.

[0172] In an exemplary embodiment, the device further comprises a position inheritance module for inheriting the rack end position of the previous cycle in the current cycle when the rack end position of the previous cycle is valid, and the position inheritance module comprises:

[0173] The position inheritance module is used to determine the rack end position of the previous cycle as the rack end position of the current cycle.

[0174] In an exemplary embodiment, the device further comprises a median invalid module, the median invalid module comprising:

[0175] The invalid center position module is used to use the calibrated rack center position as the actual rack center position when the actual rack center position is invalid.

[0176] It should be noted that the device provided in the above embodiment, when implementing its functions, is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device and method embodiments provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0177] An embodiment of the present application provides an electronic device, which includes a processor and a memory, wherein the memory stores at least one instruction or at least one program, and the at least one instruction or the at least one program is loaded and executed by the processor to implement any rack calibration method of a wire-controlled steering system provided in the above-mentioned method embodiments.

[0178] The memory can be used to store software programs and modules. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, application programs required for functions, etc.; the data storage area can store data created according to the use of the device, etc. In addition, the memory can include a high-speed random access memory and can also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices. Accordingly, the memory can also include a memory controller to provide the processor with access to the memory.

[0179] The method embodiments provided in the embodiments of the present application may be executed in a computer terminal, a server or a similar computing device, that is, the above-mentioned electronic device may include a computer terminal, a server or a similar computing device. Figure 7 is a hardware structure block diagram of a computer device for running a rack calibration method for a wire-controlled steering system provided by an embodiment of the present invention, such as Figure 7 As shown, the internal structure of the computer device may include but is not limited to: a processor, a network interface and a memory. The processor, network interface and memory in the computer device may be connected via a bus or other means. Figure 7 The example of connecting through bus is taken in the following.

[0180] Among them, the processor (or CPU (Central Processing Unit)) is the computing core and control core of the computer device. The network interface may optionally include a standard wired interface, a wireless interface (such as WI-FI, a mobile communication interface, etc.). The memory is a memory device in a computer device for storing programs and data. It is understandable that the memory here can be a high-speed RAM storage device or a non-volatile memory device (non-volatile memory), such as at least one disk storage device; optionally, it can also be at least one storage device located away from the aforementioned processor. The memory provides a storage space, which stores the operating system of the electronic device, which may include but is not limited to: Windows system (an operating system), Linux (an operating system), Android (Android, a mobile operating system) system, IOS (a mobile operating system) system, etc., and the present invention is not limited to this; and, in the storage space, one or more instructions suitable for being loaded and executed by the processor are also stored, and these instructions may be one or more computer programs (including program codes). In the embodiment of this specification, the processor loads and executes one or more instructions stored in the memory to implement the rack calibration method of the wire control steering system provided in the above method embodiment.

[0181] An embodiment of the present application also provides a computer-readable storage medium, which can be set in an electronic device to store at least one instruction or at least one program related to implementing a rack calibration method for a wire-controlled steering system. The at least one instruction or the at least one program is loaded and executed by the processor to implement any rack calibration method for a wire-controlled steering system provided by the above-mentioned method embodiments.

[0182] Optionally, in this embodiment, the above-mentioned storage medium may include but is not limited to: a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and other media that can store program codes.

[0183] It should be noted that the above-mentioned sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above-mentioned specific embodiments of this specification are described. Other embodiments are within the scope of the attached claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0184] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0185] 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.

[0186] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A rack calibration method for a steer-by-wire system, characterized in that: The method comprises: Acquire the actual rack center position of the current cycle; the actual rack center position is the rack center position collected when the target vehicle is in a straight-ahead state in the current cycle; Determine the difference between the actual rack center position and the calibrated rack center position to obtain the rack center position deviation; the calibrated rack center position is the rack center position collected when the target vehicle is in a straight-ahead state under ideal conditions; Based on at least one of the rack median deviation and the confidence of the rack end position in the previous cycle, determining whether the rack end position in the previous cycle is valid; In the case where the rack end position of the previous cycle is invalid, determining the rack end position of the current cycle based on the rack design stroke and the rack median deviation; The confidence level of the rack end position of the current cycle is determined based on the rack median deviation.

2. The rack calibration method of a steer-by-wire system according to claim 1, characterized in that: The step of determining the rack end position of the current cycle based on the rack design stroke and the rack median deviation comprises: Acquire a plurality of median deviation thresholds within a stroke difference range; the stroke difference range is determined based on the rack design stroke and the rack mechanical stroke; Selecting a median deviation threshold from the multiple median deviation thresholds; the selected median deviation threshold is smaller than any unselected threshold from the multiple median deviation thresholds; In the case where the rack median deviation is less than or equal to the selected median deviation threshold, a median deviation threshold is selected from the remaining median deviation thresholds, until the rack median deviation is greater than the selected median deviation threshold, the selected median deviation threshold is determined as the target median deviation threshold; the remaining median deviation threshold is a threshold that has not been selected from the multiple median deviation thresholds; Based on the calculation rule corresponding to the rack design stroke and the target median deviation threshold, the rack end position of the current cycle is determined.

3. The rack calibration method of a steer-by-wire system according to claim 2, characterized in that: The step of determining the confidence level of the rack end position of the current cycle based on the rack median deviation comprises: Acquire threshold confidence mapping information; the threshold confidence mapping information includes a mapping relationship between each median deviation threshold and the confidence of the rack end position; the median deviation threshold is negatively correlated with the confidence of the rack end position; The confidence corresponding to the target median deviation threshold is determined in the threshold confidence mapping information to obtain the confidence of the rack end position in the current cycle.

4. The rack calibration method of a steer-by-wire system according to claim 3, characterized in that: The determining whether the rack end position of the previous cycle is valid based on at least one of the rack median deviation and the confidence of the rack end position of the previous cycle includes: Selecting a critical median deviation threshold from the multiple median deviation thresholds; the critical median deviation threshold is greater than any unselected threshold from the multiple median deviation thresholds; Determining the confidence corresponding to the critical median deviation threshold in the threshold confidence mapping information to obtain a confidence threshold; In the case where the confidence of the rack end position in the previous cycle is greater than the confidence threshold, it is determined that the rack end position in the previous cycle is valid.

5. The rack calibration method of a steer-by-wire system according to claim 1, characterized in that: The determining whether the rack end position of the previous cycle is valid based on at least one of the rack median deviation and the confidence of the rack end position of the previous cycle includes: Get the rack median deviation of the historical period; Based on the rack median deviation of the historical period and the rack median deviation of the current period, evaluating whether the rack median deviation is always credible; In the case where the rack center deviation is always credible, it is determined that the rack end position of the previous cycle is valid.

6. The rack calibration method of a steer-by-wire system according to claim 4 or 5, characterized in that: The method further comprises: The rack end position of the previous cycle is determined as the rack end position of the current cycle.

7. The rack calibration method of a steer-by-wire system according to claim 1, characterized in that: The method further comprises: In the case where the actual rack center position is invalid, the calibrated rack center position is used as the actual rack center position.

8. A rack calibration device for a steer-by-wire system, characterized in that: The device comprises: A median position acquisition module, used to acquire an actual rack median position of the current cycle; the actual rack median position is the rack median position acquired when the target vehicle is in a straight-ahead state in the current cycle; A median deviation module is used to determine the difference between the actual rack median and the calibrated rack median to obtain the rack median deviation; the calibrated rack median is the rack median collected when the target vehicle is in a straight-ahead state under ideal conditions; A validity judgment module, used for judging whether the rack end position of the previous cycle is valid based on at least one of the rack median deviation and the confidence of the rack end position of the previous cycle; An end determination module, used to determine the end position of the rack in the current cycle based on the rack design stroke and the rack median deviation when the rack end position of the previous cycle is invalid; A confidence determination module is used to determine the confidence of the rack end position in the current cycle based on the rack median deviation.

9. An electronic device, characterized in that: It comprises a processor and a memory, wherein the memory stores at least one instruction or at least one program, and the at least one instruction or the at least one program is loaded and executed by the processor to implement the rack calibration method of the wire control steering system according to any one of claims 1 to 7.

10. A computer-readable storage medium, wherein at least one instruction or at least one program is stored in the storage medium, wherein the at least one instruction or the at least one program is loaded and executed by a processor to implement the rack calibration method of a steer-by-wire system according to any one of claims 1 to 7.

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