Steering wheel and rack alignment method and device, steer-by-wire system and storage medium

Abstract

The invention relates to the technical field of vehicles, and provides a steering wheel and rack alignment method and device, a steer-by-wire system and a storage medium. The method comprises the steps that firstly, according to an ignition signal, a vehicle door signal and a detection signal of a steering mechanism, whether a power-off alignment condition is met or not is judged; when a power-off alignment condition is met, calculating an angle error according to a steering wheel angle and a rack position, and calculating a power-off alignment torque according to the angle error; and adjusting the angle of the steering wheel according to the power-off alignment torque so as to align the steering wheel with the rack. Therefore, automatic alignment of the steering wheel and the rack when the vehicle is powered off is achieved, dislocation of the steering wheel and the rack caused by tire force release when the vehicle is powered off is effectively solved, frequent alignment operation when the vehicle is powered on is avoided, and the driving experience is improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a method and device for aligning a steering wheel with a rack, a wire-controlled steering system and a storage medium. Background Art

[0002] Traditional EPS (Electric Power Steering) uses a mechanical transmission mechanism to ensure that the steering wheel angle is aligned with the rack position. However, SBW (Steering By Wire) eliminates the intermediate shaft, so the steering wheel and rack are no longer directly connected through a mechanical transmission mechanism, so the steering wheel and rack are aligned through the angle alignment control module. The angle alignment control module not only has the function of aligning the steering wheel and rack in traditional EPS, but also can achieve precise alignment of the steering wheel and rack during the switching process between automatic driving and manual driving, and between game mode and driving mode.

[0003] However, when the angle alignment control module is used, when the vehicle is powered off, the tire force loss will cause an error between the steering wheel angle and the rack position. And the closer the steering wheel is to the end position, that is, the closer it is to the maximum angle, the greater the tire force loss will be when the power is off, and the greater the error between the steering wheel angle and the rack position. If the existing alignment strategy is used, that is, alignment is performed when the vehicle is powered on next time, the driving experience will be affected due to frequent alignment every time the power is turned on. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a method and device for aligning a steering wheel with a rack, a steer-by-wire system and a storage medium.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for aligning a steering wheel with a rack, the method comprising:

[0007] According to the ignition signal, the door signal and the detection signal of the steering mechanism, it is judged whether the power-off alignment condition is met;

[0008] When the power-off alignment condition is met, an angle error is calculated according to the steering wheel angle and the rack position, and a power-off alignment torque is calculated according to the angle error;

[0009] The steering wheel angle is adjusted according to the lower power alignment torque to align the steering wheel with the rack.

[0010] In an optional implementation manner, the step of determining whether the power-off alignment condition is met based on the ignition signal, the door signal, and the detection signal of the steering mechanism includes:

[0011] Determine the vehicle state according to the ignition signal, determine the door state according to the door signal, and determine the steering mechanism state according to the detection signal of the steering mechanism;

[0012] If the vehicle state is a start state, or the door state is an open state, or the steering mechanism state is an abnormal state, it is determined that the power-off alignment condition is not met;

[0013] If the vehicle state is an ignition-off state, the door state is a closed state, and the steering mechanism state is a normal state, it is determined that the power-off alignment condition is met.

[0014] In an optional embodiment, the step of calculating the angle error according to the steering wheel angle and the rack position, and calculating the lower electric alignment torque according to the angle error includes:

[0015] Calculating a target steering wheel angle according to a preset transmission ratio and the rack position; the target steering wheel angle represents a steering wheel angle aligned with the rack position;

[0016] Collecting the steering wheel angle according to a preset time period, and calculating the current angle error based on the currently collected steering wheel angle and the target steering wheel angle;

[0017] The corresponding target rotation speed is determined according to the current angle error, and the current power-down alignment torque is calculated based on the target rotation speed.

[0018] In an optional implementation manner, the step of determining the corresponding target speed according to the current angle error includes:

[0019] Obtain a preset speed adjustment table, wherein the speed adjustment table includes a plurality of angle errors arranged from small to large and a speed corresponding to each angle error;

[0020] If the rotation speed adjustment table contains an angle error that is the same as the current angle error, the rotation speed corresponding to the angle error is used as the target rotation speed corresponding to the current angle error;

[0021] If the speed adjustment table does not contain an angle error identical to the current angle error, two reference angle errors and their corresponding speeds are obtained from the speed adjustment table; the two reference angle errors are the first angle error in the speed adjustment table that is larger than the current angle error and the previous angle error;

[0022] A linear function is established according to the two reference angle errors and their corresponding rotational speeds, and a target rotational speed corresponding to the current angle error is calculated according to the linear function and the current angle error.

[0023] In an optional implementation, the step of calculating the current power-down alignment torque based on the target speed includes:

[0024] Calculate the steering wheel angle change according to the steering wheel angle collected this time and the steering wheel angle collected last time;

[0025] Calculating the current steering wheel speed according to the steering wheel angle change and the time period;

[0026] Calculating a current speed difference according to the current steering wheel speed and the target speed;

[0027] Based on the current rotational speed difference and each accumulated rotational speed difference, the current power-off alignment torque is calculated.

[0028] In an optional implementation manner, the formula for calculating the power-down alignment torque is:

[0029]

[0030] Among them, u(n) represents the alignment torque of this power-down, e(n) represents the speed difference of this time, e(i) represents the speed difference of the i+1th time, k P represents the proportionality coefficient, k I Represents the integral coefficient.

[0031] In an optional embodiment, the method for aligning the steering wheel with the rack further includes:

[0032] Determine whether the power-on alignment condition is met based on the ignition signal, the door signal and the detection signal of the steering mechanism;

[0033] When the power-on alignment condition is met, the power-on alignment torque is calculated based on the error between the steering wheel angle and the rack position;

[0034] The steering wheel angle or the rack position is adjusted according to the power-on alignment torque to align the steering wheel with the rack.

[0035] In a second aspect, the present invention provides a steering wheel and rack alignment device, the steering wheel and rack alignment device comprising:

[0036] A judgment module, used to judge whether the power-off alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism;

[0037] A calculation module, used for calculating an angle error according to a steering wheel angle and a rack position when a power-off alignment condition is met, and calculating a power-off alignment torque according to the angle error;

[0038] The adjustment module is used to adjust the steering wheel angle according to the lower power alignment torque to align the steering wheel with the rack.

[0039] In a third aspect, the present invention provides a wire-controlled steering system, comprising a controller and a memory, wherein the memory stores a computer program, and when the controller executes the computer program, the steering wheel and rack alignment method described in any one of the aforementioned embodiments is implemented.

[0040] In a fourth aspect, the present invention provides a storage medium having a computer program stored thereon, which, when executed by a controller, implements the method for aligning a steering wheel and a rack as described in any one of the aforementioned embodiments.

[0041] The present invention provides a method, device, wire-controlled steering system and storage medium for aligning a steering wheel with a rack. The method comprises: first, judging whether the power-off alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism; then, when the power-off alignment condition is met, calculating the angle error according to the steering wheel angle and the rack position, and calculating the power-off alignment torque according to the angle error; and then adjusting the steering wheel angle according to the power-off alignment torque to align the steering wheel with the rack. Thus, the steering wheel and the rack are automatically aligned when the vehicle is powered off, effectively solving the misalignment of the steering wheel and the rack caused by tire leakage when the vehicle is powered off, and avoiding frequent alignment operations when the vehicle is powered on, thereby improving the driving experience.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 One of the flow charts of the method for aligning a steering wheel and a rack provided by an embodiment of the present invention is shown;

[0045] Figure 2 The second schematic flow chart of the method for aligning a steering wheel and a rack provided in an embodiment of the present invention is shown;

[0046] Figure 3 A schematic diagram of a steer-by-wire system provided by an embodiment of the present invention is shown;

[0047] Figure 4 A functional module diagram of a steering wheel and rack alignment device provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0048] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0050] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0051] See also Figure 1 , is a flow chart of a method for aligning a steering wheel and a rack provided in an embodiment of the present invention.

[0052] Step S202, judging whether the power-off alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism.

[0053] Step S204: when the power-off alignment condition is met, an angle error is calculated according to the steering wheel angle and the rack position, and a power-off alignment torque is calculated according to the angle error.

[0054] Step S206, adjusting the steering wheel angle according to the power-off alignment torque to align the steering wheel with the rack.

[0055] It is understandable that in the case where the steering wheel and the rack are misaligned due to tire leakage when the vehicle is powered off, if the existing alignment strategy is used, the steering wheel and the rack will not be aligned until the vehicle is powered on. This will cause the driver to not move the steering wheel after getting off the vehicle, but need to be realigned when starting the vehicle again, thus affecting the driver's driving experience.

[0056] Therefore, the embodiment of the present invention performs the process of aligning the steering wheel and the rack when the vehicle is powered off, so as to avoid affecting the driving experience by aligning when powered on. It should be noted that the vehicle power-off mentioned in the embodiment of the present invention does not mean that the vehicle is completely powered off, but that the power system of the vehicle is turned off.

[0057] In this embodiment, it is possible to first determine whether the power-off alignment condition is met based on the ignition signal, the door signal, and the detection signal of the steering mechanism, that is, to determine whether to execute the power-off alignment process. If the power-off alignment condition is met, then the power-off alignment process is executed, that is, the angle error is calculated based on the steering wheel angle and the rack position, and the power-off alignment torque is calculated based on the angle error; then the steering wheel angle is adjusted based on the power-off alignment torque to align the steering wheel with the rack. It can be understood that since the power system is turned off when the vehicle is powered off, the embodiment of the present invention is to align the steering wheel with the rack by adjusting the steering wheel.

[0058] It can be seen that based on the above steps, firstly, according to the ignition signal, the door signal and the detection signal of the steering mechanism, it is judged whether the power-off alignment condition is met; then when the power-off alignment condition is met, the angle error is calculated according to the steering wheel angle and the rack position, and the power-off alignment torque is calculated according to the angle error; then the steering wheel angle is adjusted according to the power-off alignment torque to align the steering wheel with the rack. Thus, the steering wheel and the rack are automatically aligned when the vehicle is powered off, which effectively solves the misalignment of the steering wheel and the rack caused by tire leakage when the vehicle is powered off, and avoids frequent alignment operations when the vehicle is powered on, which improves the driving experience.

[0059] Optionally, for step S202, an embodiment of the present invention provides a possible implementation method.

[0060] Step S202-1, determining the vehicle state according to the ignition signal, determining the door state according to the door signal, and determining the steering mechanism state according to the detection signal of the steering mechanism.

[0061] Step S202-2: if the vehicle state is in the start state, or the door state is in the open state, or the steering mechanism state is in the abnormal state, it is determined that the power-off alignment condition is not met.

[0062] Step S202-3: if the vehicle is in an ignition-off state, the door is in a closed state, and the steering mechanism is in a normal state, it is determined that the power-off alignment condition is met.

[0063] In this embodiment, the vehicle state can be determined according to the ignition signal. For example, when the ignition signal is in an activated state, it means that the vehicle state is in a starting state, that is, the power system is in an on state; when the ignition signal is in an inactivated state, it means that the vehicle state is in an off state, that is, the power system is in an off state. In addition, the door state can be determined according to the door signal, that is, whether the door is closed or open.

[0064] In addition, the state of the steering mechanism can be determined based on the detection signal of the steering mechanism. The steering mechanism can be understood as a mechanism for turning the steering wheel, which includes components such as a power steering motor. It can be understood that since the power-off alignment process requires turning the steering wheel, it is necessary to determine the state of the steering mechanism based on the detection signal of the steering mechanism to determine whether the steering wheel can be turned normally. If the state of the steering mechanism is normal, it means that the steering wheel can be turned normally; if the state of the steering mechanism is abnormal, it means that the steering wheel cannot be turned normally.

[0065] Then, it can be determined whether to trigger the power-off alignment signal, that is, whether the power-off alignment condition is met, based on the obtained vehicle state, door state, and steering mechanism state. If the vehicle state is in the start state, the power-off alignment signal is not triggered, that is, it is determined that the power-off alignment condition is not met. If the door state is in the open state, the power-off alignment signal is not triggered, that is, it is determined that the power-off alignment condition is not met. If the steering mechanism state is in an abnormal state, the power-off alignment signal is not triggered, that is, it is determined that the power-off alignment condition is not met. If the vehicle state is in the ignition-off state, the door state is in the closed state, and the steering mechanism state is in the normal state, the power-off alignment signal is triggered, that is, it is determined that the power-off alignment condition is met.

[0066] Optionally, for step S204, the present invention provides a possible implementation method, see Figure 2 .

[0067] Step S204-1, calculating a target steering wheel angle according to a preset transmission ratio and rack position; the target steering wheel angle represents a steering wheel angle aligned with the rack position.

[0068] Step S204-2, collecting the steering wheel angle according to a preset time period, and calculating the current angle error based on the currently collected steering wheel angle and the target steering wheel angle.

[0069] Step S204-3, determining the corresponding target speed according to the current angle error, and calculating the current power-off alignment torque based on the target speed.

[0070] In this embodiment, when the power-off alignment condition is met, the position of the rack at power-off can be obtained first to obtain the rack position, and the steering wheel angle when aligned with the rack position is calculated according to the rack position and the preset transmission ratio, that is, the target steering wheel angle is obtained. For example, the target steering wheel angle can be obtained by multiplying the rack position by the transmission ratio.

[0071] Then, during the process of adjusting the steering wheel, the steering wheel angle will change, so the steering wheel angle can be collected according to the preset time period. And each time the steering wheel angle is collected, the power-down alignment torque of that time will be calculated, and the power steering motor will be controlled according to the power-down alignment torque to drive the steering wheel to rotate, so that the steering wheel angle changes. After multiple adjustments, the steering wheel angle can be adjusted to an angle aligned with the rack position, that is, the steering wheel and the rack are aligned.

[0072] It is understandable that the method of calculating the power-off alignment torque based on the steering wheel angle collected each time is similar. For simplicity, the embodiment of the present invention takes the steering wheel angle collected once as an example for explanation. For example, firstly, the difference is calculated based on the steering wheel angle collected this time and the target steering wheel angle, that is, the angle error is obtained this time, and then the corresponding target speed is determined based on the angle error this time, and the power-off alignment torque is calculated based on the target speed.

[0073] Optionally, for the process of determining the corresponding target rotation speed according to the current angle error in step S204-5, an embodiment of the present invention provides a possible implementation method.

[0074] Step S204-5-1, obtaining a preset speed adjustment table, the speed adjustment table including a plurality of angle errors arranged from small to large and the speed corresponding to each angle error.

[0075] Step S204-5-2: If there is an angle error identical to the current angle error in the speed adjustment table, the speed corresponding to the angle error is used as the target speed corresponding to the current angle error.

[0076] Step S204-5-3, if the angle error identical to the current angle error does not exist in the speed adjustment table, obtain two reference angle errors and their corresponding speeds from the speed adjustment table; the two reference angle errors are the first angle error in the speed adjustment table that is larger than the current angle error and the previous angle error.

[0077] Step S204-5-4, establishing a linear function based on the two reference angle errors and their corresponding rotational speeds, and calculating the target rotational speed corresponding to the current angle error based on the linear function and the current angle error.

[0078] It is understandable that, since the angle of the steering wheel will constantly change, the angle error of the steering wheel will also constantly change, so a speed adjustment table can be set in advance to control the speed of adjusting the steering wheel angle.

[0079] In this embodiment, a preset speed adjustment table can be obtained first, and the speed adjustment table includes multiple angle errors arranged from small to large and the speeds corresponding to each angle error. For ease of understanding, an embodiment of the present invention provides an example of a speed adjustment table, and some information is shown in the following table.

[0080]

[0081] According to the information in the table, the speed decreases as the angle error decreases. That is, the adjustment strategy of the speed adjustment table is: when the angle error of the steering wheel is large, the steering wheel speed is expected to be large, that is, the steering wheel angle is inclined to be adjusted quickly; when the angle error of the steering wheel is small, the steering wheel speed is expected to be small, that is, the steering wheel angle is inclined to be adjusted slowly.

[0082] It should be noted that the specific values ​​of the angle error and the rotational speed in the above table, as well as the specific numbers of the angle error and the rotational speed are merely examples, and they can all be set according to actual conditions. The adjustment strategy of the speed adjustment table can be set according to actual conditions, and the embodiments of the present invention are not limited to this.

[0083] Then, according to the current angle error, search in the speed adjustment table. If the angle error that is the same as the current angle error is found, then the speed corresponding to the angle error is used as the target speed corresponding to the current angle error. If the angle error that is the same as the current angle error is not found, then the first angle error that is larger than the current angle error and the angle error before the angle error are obtained from the speed adjustment table, that is, two reference angle errors are obtained, and the speeds corresponding to the two reference angle errors are obtained.

[0084] It can be understood that the interval formed by the two reference angle errors is the minimum interval containing the current angle error. Then a linear function can be established based on the two reference angle errors and their corresponding rotational speeds. This linear function can be understood as the correlation between the angle error and the rotational speed within the interval formed by the two reference angle errors. Then the target rotational speed corresponding to the current angle error can be calculated based on this linear function and the current angle error.

[0085] Optionally, for the process of calculating the current power-down alignment torque based on the target rotation speed in step S204-5, an embodiment of the present invention provides a possible implementation method.

[0086] Step S204-5-5, calculating the steering wheel angle change according to the steering wheel angle collected this time and the steering wheel angle collected last time;

[0087] Step S204-5-6, calculating the current steering wheel speed according to the steering wheel angle change and the time period;

[0088] Step S204-5-7, calculating the current speed difference according to the current steering wheel speed and the target speed;

[0089] Step S204-5-8, based on the current speed difference and the accumulated speed difference each time, calculate the power-off alignment torque for this time.

[0090] In this embodiment, first, the steering wheel angle change is calculated based on the steering wheel angle collected this time and the steering wheel angle collected last time. And the steering wheel speed is calculated based on the steering wheel angle change and the time period. Then the difference between the steering wheel speed and the target speed is calculated to obtain the speed difference. Then, based on the speed difference and the accumulated speed difference, the power-off alignment torque can be calculated.

[0091] For example, the PI (Proportional, Integral) adjustment algorithm can be used to calculate the current power-off alignment torque based on the current speed difference and the accumulated speed difference each time. The process of calculating the current power-off alignment torque can be expressed by the formula, that is:

[0092]

[0093] Among them, u(n) represents the alignment torque of this power-down, e(n) represents the speed difference of this time, e(i) represents the speed difference of the i+1th time, k P represents the proportionality coefficient, k I Indicates the integral coefficient. In addition, u(n) can also be understood as the n+1th power-down alignment torque, and e(n) can also be understood as the n+1th speed difference.

[0094] It is understandable that, in one implementation, the torque control range of the power steering motor can be referred to to set the corresponding proportional coefficient and integral coefficient, so that the calculated power-off alignment torque belongs to the torque control range, and then the power steering motor can be directly controlled according to the power-off alignment torque. In another implementation, a scaling parameter can also be set to adjust the calculated power-off alignment torque. That is, when the power-off alignment torque does not belong to the torque control range of the power steering motor, the scaling parameter can be used to reduce or amplify the value of the power-off alignment torque, so that the scaled power-off alignment torque belongs to the torque control range, and then the power steering motor is controlled according to the scaled power-off alignment torque.

[0095] Furthermore, after multiple calculations, the electric alignment torque is used to control the power steering motor to drive the steering wheel angle, and the speed difference gradually approaches zero. When the speed difference is equal to zero or falls within a preset range close to zero, the steering wheel is considered to be aligned with the rack.

[0096] Optionally, an embodiment of the present invention further provides a method for aligning the steering wheel and the rack when power is turned on.

[0097] Step S208, judging whether the power-on alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism.

[0098] Step S210: When the power-on alignment condition is met, the power-on alignment torque is calculated according to the error between the steering wheel angle and the rack position.

[0099] Step S212: adjusting the steering wheel angle or the rack position according to the power-on alignment torque to align the steering wheel with the rack.

[0100] It is understandable that in order to cope with the situation where the driver moves the steering wheel again after the steering wheel and the rack are aligned when the vehicle is powered off, the embodiment of the present invention also provides a method for aligning the steering wheel and the rack when powered on. That is, it is determined whether the power-on alignment condition is met based on the ignition signal, the door signal and the detection signal of the steering mechanism.

[0101] For example, the vehicle state is determined according to the ignition signal, the door state is determined according to the door signal, and the steering mechanism state is determined according to the detection signal of the steering mechanism. If the vehicle state is the ignition off state, it is determined that the power-on alignment condition is not met. If the door state is the open state, it is determined that the power-on alignment condition is not met. If the steering mechanism state is the abnormal state, it is determined that the power-on alignment condition is not met. If the vehicle state is the start state, the door state is the closed state, and the steering mechanism state is the normal state, it is determined that the power-on alignment condition is met.

[0102] When the power-on alignment condition is met, the power-on alignment torque is calculated based on the error between the steering wheel angle and the rack position. For example, in one implementation, the rack position can be used as a reference to calculate the angle error of the steering wheel angle, and the power-on alignment torque is calculated based on the angle error. In another implementation, the steering wheel angle can also be used as a reference to calculate the position error of the rack position, and the power-on alignment torque is calculated based on the position error.

[0103] Next, if the power-on alignment torque is calculated based on the angle error, the steering wheel angle is adjusted according to the power-on alignment torque to adjust the steering wheel angle to an angle aligned with the rack position, that is, to achieve alignment between the steering wheel and the rack. If the power-on alignment torque is calculated based on the position error, the rack position is adjusted according to the power-on alignment torque to adjust the rack position to a position corresponding to the steering wheel angle, that is, to achieve alignment between the steering wheel and the rack.

[0104] In order to perform the corresponding steps in the above embodiments and various possible methods, a method for implementing a steering wheel and rack alignment device is provided below. Figure 3 , is a functional module diagram of the steering wheel and rack alignment device provided by an embodiment of the present invention. It should be noted that the basic principle and technical effects of the steering wheel and rack alignment device provided by this embodiment are the same as those of the above embodiment. For the sake of brief description, for matters not mentioned in this embodiment, reference can be made to the corresponding contents in the above embodiment. The steering wheel and rack alignment device includes:

[0105] The judgment module is used to judge whether the power-off alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism.

[0106] The calculation module is used to calculate the angle error according to the steering wheel angle and the rack position when the power-off alignment condition is met, and calculate the power-off alignment torque according to the angle error.

[0107] An adjustment module is used to adjust the steering wheel angle according to the power-down alignment torque to align the steering wheel with the rack.

[0108] Optionally, the judgment module is also used to: determine the vehicle state according to the ignition signal, determine the door state according to the door signal, and determine the steering mechanism state according to the detection signal of the steering mechanism; if the vehicle state is a start state, or the door state is an open state, or the steering mechanism state is an abnormal state, it is determined that the power-off alignment condition has not been met; if the vehicle state is an off state, the door state is a closed state, and the steering mechanism state is a normal state, it is determined that the power-off alignment condition has been met.

[0109] Optionally, the calculation module is also used to: calculate the target steering wheel angle according to a preset transmission ratio and rack position; the target steering wheel angle represents the steering wheel angle aligned with the rack position; collect the steering wheel angle according to a preset time period, and calculate the current angle error based on the steering wheel angle collected this time and the target steering wheel angle; determine the corresponding target speed based on the current angle error, and calculate the power-off alignment torque based on the target speed.

[0110] Optionally, the calculation module is also used to: obtain a preset speed adjustment table, the speed adjustment table includes multiple angle errors arranged from small to large and the speeds corresponding to each angle error; if there is an angle error identical to the current angle error in the speed adjustment table, then the speed corresponding to the angle error is used as the target speed corresponding to the current angle error; if there is no angle error identical to the current angle error in the speed adjustment table, then obtain two reference angle errors and their corresponding speeds from the speed adjustment table; the two reference angle errors are the first angle error in the speed adjustment table that is larger than the current angle error and the previous angle error; establish a linear function based on the two reference angle errors and their corresponding speeds, and calculate the target speed corresponding to the current angle error based on the linear function and the current angle error.

[0111] Optionally, the calculation module is also used to: calculate the steering wheel angle change based on the steering wheel angle collected this time and the steering wheel angle collected last time; calculate the steering wheel speed based on the steering wheel angle change and the time period; calculate the speed difference based on the steering wheel speed and the target speed; calculate the power-off alignment torque based on the speed difference and the accumulated speed difference each time.

[0112] Optionally, the formula for calculating the power-off alignment torque is:

[0113]

[0114] Among them, u(n) represents the alignment torque of this power-down, e(n) represents the speed difference of this time, e(i) represents the speed difference of the i+1th time, k P represents the proportionality coefficient, k I Represents the integral coefficient.

[0115] Optionally, the judgment module is also used to: judge whether the power-on alignment condition is met based on the ignition signal, the door signal and the detection signal of the steering mechanism; when the power-on alignment condition is met, calculate the power-on alignment torque based on the error between the steering wheel angle and the rack position; adjust the steering wheel angle or the rack position according to the power-on alignment torque to align the steering wheel with the rack.

[0116] See also Figure 4 , is a schematic diagram of a steer-by-wire system provided by an embodiment of the present invention. The steer-by-wire system includes a controller, a memory, and a communication module, and each component is electrically connected to each other directly or indirectly to achieve data transmission or interaction. For example, these components can be electrically connected to each other via one or more communication buses or signal lines.

[0117] The controller is used to read / write data or programs stored in the memory and execute corresponding functions. It can be a general controller, including CPU (Central Processing Unit), NP (Network Processor), etc.; it can also be a DSP digital signal controller, ASIC application-specific integrated circuit, FPGA ready-made programmable gate array or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0118] Memory is used to store programs or data. Memory can be RAM (Random Access Memory), ROM (Read Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electric Erasable Programmable Read-Only Memory), etc.

[0119] The communication module is used to communicate with other devices for signaling or data.

[0120] Understandably, Figure 4 The structure shown is only a schematic diagram of the structure of the wire control steering system. The wire control steering system may also include Figure 4 More or fewer components as shown, or with Figure 4 Different configurations are shown. Figure 4 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0121] The wire-controlled steering system provided by the embodiment of the present invention includes a controller and a memory, wherein the memory stores a computer program, and when the controller executes the computer program, the steering wheel and rack alignment method disclosed by the embodiment of the present invention is implemented.

[0122] The embodiment of the present invention further provides a storage medium on which a computer program is stored. When the computer program is executed by a controller, the method for aligning the steering wheel and the rack disclosed in the embodiment of the present invention is implemented.

[0123] In several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0124] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0125] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for aligning a steering wheel and a rack, characterized in that: The steering wheel and rack alignment method comprises: According to the ignition signal, the door signal and the detection signal of the steering mechanism, it is judged whether the power-off alignment condition is met; When the power-off alignment condition is met, an angle error is calculated according to the steering wheel angle and the rack position, and a power-off alignment torque is calculated according to the angle error; The steering wheel angle is adjusted according to the lower power alignment torque to align the steering wheel with the rack.

2. The method for aligning a steering wheel and a rack according to claim 1, characterized in that: The step of judging whether the power-off alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism comprises: Determine the vehicle state according to the ignition signal, determine the door state according to the door signal, and determine the steering mechanism state according to the detection signal of the steering mechanism; If the vehicle state is a start state, or the door state is an open state, or the steering mechanism state is an abnormal state, it is determined that the power-off alignment condition is not met; If the vehicle state is an ignition-off state, the door state is a closed state, and the steering mechanism state is a normal state, it is determined that the power-off alignment condition is met.

3. The method for aligning a steering wheel and a rack according to claim 1, characterized in that: The step of calculating the angle error according to the steering wheel angle and the rack position, and calculating the lower electric alignment torque according to the angle error comprises: Calculating a target steering wheel angle according to a preset transmission ratio and the rack position; the target steering wheel angle represents a steering wheel angle aligned with the rack position; Collecting the steering wheel angle according to a preset time period, and calculating the current angle error based on the currently collected steering wheel angle and the target steering wheel angle; The corresponding target rotation speed is determined according to the current angle error, and the current power-down alignment torque is calculated based on the target rotation speed.

4. The method for aligning a steering wheel and a rack according to claim 3, characterized in that: The step of determining the corresponding target speed according to the current angle error comprises: Obtain a preset speed adjustment table, wherein the speed adjustment table includes a plurality of angle errors arranged from small to large and a speed corresponding to each angle error; If the rotation speed adjustment table contains an angle error that is the same as the current angle error, the rotation speed corresponding to the angle error is used as the target rotation speed corresponding to the current angle error; If the speed adjustment table does not contain an angle error identical to the current angle error, two reference angle errors and their corresponding speeds are obtained from the speed adjustment table; the two reference angle errors are the first angle error in the speed adjustment table that is larger than the current angle error and the previous angle error; A linear function is established according to the two reference angle errors and their corresponding rotational speeds, and a target rotational speed corresponding to the current angle error is calculated according to the linear function and the current angle error.

5. The method for aligning a steering wheel and a rack according to claim 3, characterized in that: The step of calculating the current power-down alignment torque based on the target speed includes: Calculate the steering wheel angle change according to the steering wheel angle collected this time and the steering wheel angle collected last time; Calculating the current steering wheel speed according to the steering wheel angle change and the time period; Calculating a current speed difference according to the current steering wheel speed and the target speed; Based on the current rotational speed difference and the accumulated rotational speed differences each time, the current power-off alignment torque is calculated.

6. The method for aligning a steering wheel and a rack according to claim 5, characterized in that: The formula for calculating the power-down alignment torque is: Among them, u(n) represents the alignment torque of this power-down, e(n) represents the speed difference of this time, e(i) represents the speed difference of the i+1th time, k P represents the proportionality coefficient, k I Represents the integral coefficient.

7. The method for aligning a steering wheel and a rack according to claim 1, characterized in that: The steering wheel and rack alignment method also includes: Determine whether the power-on alignment condition is met based on the ignition signal, the door signal and the detection signal of the steering mechanism; When the power-on alignment condition is met, the power-on alignment torque is calculated based on the error between the steering wheel angle and the rack position; The steering wheel angle or the rack position is adjusted according to the power-on alignment torque to align the steering wheel with the rack.

8. A device for aligning a steering wheel and a rack, characterized in that: The steering wheel and rack alignment device comprises: A judgment module, used to judge whether the power-off alignment condition is met according to the ignition signal, the door signal and the detection signal of the steering mechanism; A calculation module, used for calculating an angle error according to a steering wheel angle and a rack position when a power-off alignment condition is met, and calculating a power-off alignment torque according to the angle error; The adjustment module is used to adjust the steering wheel angle according to the lower power alignment torque to align the steering wheel with the rack.

9. A steer-by-wire system, characterized in that: The method comprises a controller and a memory, wherein the memory stores a computer program, and when the controller executes the computer program, the method for aligning the steering wheel and the rack according to any one of claims 1 to 7 is implemented.

10. A storage medium, characterized in that: The storage medium stores a computer program, which, when executed by the controller, implements the steering wheel and rack alignment method according to any one of claims 1 to 7.

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