Electric power steering active return control method and system

Abstract

The invention provides an electric power steering active return control method and system, and belongs to the field of electric power steering systems.The electric power steering active return control method comprises the steps that in the rotating process of a vehicle steering wheel, zone control is conducted with the steering wheel rotating angle as the benchmark, and original request torque is obtained; estimating the inertia moment of the steering wheel in the steering wheel aligning process; and calculating the original request torque and the steering wheel inertia torque to obtain a corrected steering wheel torque, and correcting the steering wheel torque according to the corrected steering wheel torque. According to the technical scheme, the aligning torque error caused by rotating speed fluctuation of the steering wheel is eliminated, and particularly under the working condition that a driver is completely released from the hand, the stability of aligning control is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of electric power steering systems, and in particular to an active return-to-center control method and system for electric power steering. Background Technology

[0002] Electric power steering (EPS) is a power steering system that relies directly on an electric motor to provide auxiliary torque. Compared to the traditional hydraulic power steering (HPS), EPS has many advantages. EPS mainly consists of a torque sensor, a vehicle speed sensor, an electric motor, a reduction gear, and an electronic control unit (ECU).

[0003] Until today, the performance of power steering systems had reached its limits, but the return-to-center characteristics of electric power steering systems have changed everything. When the driver turns the steering wheel at an angle and releases it, the system automatically adjusts to return the wheels to the center. This system also allows engineers to use software to adjust design parameters to the maximum extent to achieve optimal return-to-center characteristics. A set of return-to-center characteristic curves can be obtained from the lowest to the highest vehicle speed. Through flexible software programming, the torque characteristics of the motor at different vehicle speeds and under different driving conditions can be easily obtained. These torque characteristics enable the system to significantly improve steering ability, providing steering return-to-center characteristics that are perfectly matched to the vehicle's dynamic performance. In contrast, improving these characteristics in traditional hydraulic control systems requires modifying the chassis's mechanical structure, which is quite difficult to achieve. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes an active return-to-center control method and system for electric power steering.

[0005] In a first aspect, embodiments of the present invention provide an active return-to-center control method for electric power steering, comprising:

[0006] During the rotation of the vehicle's steering wheel, zone control is performed based on the steering wheel angle to obtain the original requested torque;

[0007] Estimate the steering wheel's inertial torque during the steering wheel return process;

[0008] The original requested torque and steering wheel inertia torque are calculated to obtain the corrected steering wheel torque, and the steering wheel torque is corrected based on the corrected steering wheel torque.

[0009] The zonal control based on the steering wheel angle includes:

[0010] The current steering wheel angle is read. When the steering wheel angle is higher than the preset threshold, lookup table control is used; when the steering wheel angle is lower than the preset threshold, PID control or MPS model predictive control is used.

[0011] The estimation of the steering wheel inertial torque during the steering wheel return process includes:

[0012] The moment of inertia of the part above the torque sensor is calculated by actual measurement. The angular acceleration is obtained by filtering the differential of the angular velocity read by the sensor. The additional torque generated under different angular accelerations is calculated based on the moment of inertia and angular acceleration.

[0013] The step of calculating the corrected steering wheel torque from the original requested torque and steering wheel inertia torque, and then correcting the steering wheel torque based on the corrected steering wheel torque, includes:

[0014] The corrected steering wheel torque is obtained by subtracting the calculated additional torque from the steering wheel torque measured by the torque sensor. The corresponding torque gain coefficient is then found by indexing the corrected steering wheel torque.

[0015] The method further includes:

[0016] During the steering wheel return process, an index is established for the steering wheel speed, and the corresponding speed gain coefficient is used to control the steering wheel speed.

[0017] The method further includes:

[0018] The suspension is compensated for during the steering wheel return-to-center process.

[0019] The compensation for suspension return during the steering wheel return process includes:

[0020] With the EPS system's active self-centering function turned off, measure the steering wheel torque required to maintain different angles at different vehicle speeds, and record this torque value as the mechanical self-centering torque under the current conditions.

[0021] In a second aspect, embodiments of the present invention provide an electric power steering active return-to-center control system, configured to implement the method described in any of the preceding claims, including:

[0022] The zone control unit is used to perform zone control based on the steering wheel angle during the rotation of the vehicle's steering wheel to obtain the original requested torque;

[0023] The torque estimation unit is used to estimate the steering wheel inertial torque during the steering wheel return process;

[0024] The correction unit is used to calculate the corrected steering wheel torque from the original requested torque and steering wheel inertia torque, and to correct the steering wheel torque based on the corrected steering wheel torque.

[0025] Thirdly, embodiments of the present invention provide an electronic device, comprising:

[0026] One or more processors;

[0027] Memory, used to store one or more programs;

[0028] When one or more programs are executed by one or more processors, the one or more processors implement any of the methods described above.

[0029] Fourthly, embodiments of the present invention provide a computer-readable medium storing a computer program, characterized in that the computer program, when executed by a processor, implements the steps of any of the methods described above.

[0030] The electric power steering active return-to-center control method and system provided by this invention firstly performs zoned control based on the steering wheel angle during the rotation of the vehicle's steering wheel to obtain the original requested torque. During the steering wheel return-to-center process, the steering wheel inertial torque is estimated. Then, the original requested torque and the steering wheel inertial torque are calculated to obtain the corrected steering wheel torque. The steering wheel torque is corrected based on the corrected steering wheel torque, eliminating the return-to-center torque error caused by steering wheel speed fluctuations. Especially when the driver has completely taken their hands off the wheel, the stability of the return-to-center control is significantly improved. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0032] Figure 1 This is a schematic diagram of the partition control process in an active return-to-center control method for electric power steering provided in an embodiment of the present invention;

[0033] Figure 2 This is a diagram showing the relationship between the absolute value of the steering wheel angle and the original requested torque in an electric power steering active return-to-center control method provided in an embodiment of the present invention.

[0034] Figure 3 This is a diagram showing the correspondence between the overall zone control angle and the control method in an active return-to-center control method for electric power steering provided in an embodiment of the present invention.

[0035] Figure 4 This is a diagram showing the relationship between the corrected steering wheel torque and the torque gain coefficient in an active return-to-center control method for electric power steering provided in an embodiment of the present invention.

[0036] Figure 5A diagram showing the relationship between steering wheel speed and speed gain coefficient in an active return-to-center control method for electric power steering provided in an embodiment of the present invention;

[0037] Figure 6 A diagram showing the relationship between vehicle speed and return-to-center compensation coefficient in an active return-to-center control method for electric power steering provided in an embodiment of the present invention;

[0038] Figure 7 This is a structural block diagram of an electric power steering active return-to-center control system provided in an embodiment of the present invention;

[0039] Figure 8 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0041] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0042] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0044] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0045] Existing technologies only calculate the return current based on steering wheel angle and vehicle speed, followed by smoothing. They lack consideration of steering wheel torque and speed, which can easily lead to uncontrollable steering wheel return speed during vehicle return and greatly increases calibration difficulty. Active return abnormality identification relies solely on torque and steering wheel angle, which may result in misjudgments and performance degradation. Furthermore, the active return process does not consider the rotational inertia of the steering wheel or the vehicle's own return characteristics, thus exhibiting poor robustness to different vehicles.

[0046] To address at least one of the technical problems existing in the aforementioned related technologies, the present invention provides an active return-to-center control method and system for electric power steering. Wherein: Figure 1 This is a schematic diagram of the partition control process in an active return-to-center control method for electric power steering provided in an embodiment of the present invention; Figure 2 This is a diagram showing the relationship between the absolute value of the steering wheel angle and the original requested torque in an electric power steering active return-to-center control method provided in an embodiment of the present invention. Figure 3 This is a diagram showing the correspondence between the overall zone control angle and the control method in an active return-to-center control method for electric power steering provided in an embodiment of the present invention. Figure 4 This is a diagram showing the relationship between the corrected steering wheel torque and the torque gain coefficient in an active return-to-center control method for electric power steering provided in an embodiment of the present invention. Figure 5 A diagram showing the relationship between steering wheel speed and speed gain coefficient in an active return-to-center control method for electric power steering provided in an embodiment of the present invention; Figure 6 A diagram showing the relationship between vehicle speed and return-to-center compensation coefficient in an active return-to-center control method for electric power steering provided in an embodiment of the present invention; Figure 7 This is a structural block diagram of an electric power steering active return-to-center control system provided in an embodiment of the present invention; Figure 8 This is a structural block diagram of an electronic device provided in an embodiment of the present invention.

[0047] As an embodiment of the present invention, the present invention provides an active return-to-center control method for electric power steering, comprising:

[0048] During the rotation of the vehicle's steering wheel, zone control is performed based on the steering wheel angle to obtain the original requested torque;

[0049] Estimate the steering wheel's inertial torque during the steering wheel return process;

[0050] The original requested torque and steering wheel inertia torque are calculated to obtain the corrected steering wheel torque, and the steering wheel torque is corrected based on the corrected steering wheel torque.

[0051] The electric power steering active return-to-center control method provided by this invention first performs zoned control based on the steering wheel angle during the rotation of the vehicle's steering wheel to obtain the original requested torque. During the return-to-center process, the steering wheel inertial torque is estimated. Then, the original requested torque and the steering wheel inertial torque are calculated to obtain the corrected steering wheel torque. The steering wheel torque is corrected based on the corrected steering wheel torque, eliminating the return-to-center torque error caused by steering wheel speed fluctuations. Especially when the driver has completely taken their hands off the wheel, it significantly improves the stability of the return-to-center control.

[0052] The above embodiments are further refined, specifically the partition control. See [link to relevant documentation]. Figure 1 By reading the current steering wheel angle, lookup table control is used when the steering wheel angle is large, and PID control or MPS model predictive control is used when the steering wheel angle is small. Lookup table control can control the return torque and return speed by calibrating the relationship between the steering wheel angle and the return torque, thus controlling the speed of the steering wheel return process and ensuring that the steering wheel returns to center evenly. However, lookup table control has many parameters and is difficult to calibrate at small angles, so it is more suitable for controlling large-angle return and not suitable for control near the zero point of the steering wheel angle. PID control is precise and has a uniform return speed when controlling the return near the zero point of the steering wheel angle, but if it is at the beginning of the return at a large angle, it will result in a large torque demand, so it is easy to have a fast return speed at large angles and an uneven return speed at medium angles.

[0053] Based on the characteristics of the two control methods mentioned above, this invention introduces a partitioned control method to obtain the original requested torque. .

[0054] Lookup table control uses the absolute value of the steering wheel angle. An index is created to find the corresponding raw torque request by reading the current steering wheel angle from the sensor. The calibrated value is the absolute value of the steering wheel angle. and the corresponding original requested torque The absolute value of the current steering wheel angle Greater than the angle threshold At that time, a lookup table control is used, based on the steering wheel speed. Calculate the original requested torque The correspondence is as follows: Figure 2 .

[0055] The PID control uses incremental discrete PID control, and the specific formula is as follows:

[0056]

[0057]

[0058] Scalar is a proportionality coefficient Integral coefficient Differential coefficients To achieve smoother control, the PID control system also employs two-stage partitioning, specifically controlling the absolute value of the steering wheel angle. Greater than the angle threshold And less than the angle threshold When using large-angle PD control, the proportional coefficient is used in the calculation. Integral coefficient Differential coefficients absolute value of steering wheel angle Greater than 0 and less than the angle threshold When using large-angle PID control, the proportional coefficient is used for calculation. Integral coefficient Differential coefficients The correspondence between the overall zone control angle and control method is as follows: Figure 3 .

[0059] Zoned control ensures that lookup table control is used at large angles, allowing for both fast and uniform steering wheel return to center when using lookup table control for large angles, and enabling uniform deceleration and accurate return to near 0 point when using PID or MPS control for small angles.

[0060] Further refining the above embodiments, the inertial torque of the steering wheel is estimated during the steering wheel return-to-center process. Specifically, during the rotation of the vehicle's steering wheel, due to the rotational inertia of the steering wheel, column, and other mechanical structures, a torque is applied to the torque sensor as the steering wheel's angular acceleration changes, thus affecting the return-to-center process and even causing the rotational speed to fluctuate repeatedly, sometimes fast and sometimes slow. Therefore, estimating the steering wheel's rotational inertia and eliminating the influence of the generated additional torque improves the speed control of active return-to-center.

[0061] The moment of inertia J of the part above the torque sensor (including the steering wheel, column, etc.) was measured by actual measurement, and the rotational inertia generated under different angular accelerations was calculated using formulas. Angular acceleration The additional torque can be obtained by differentiating the angular velocity read from the sensor and then filtering it. The formula for calculating the additional torque is as follows:

[0062]

[0063] Because using only the original steering wheel torque M0 for calculation is prone to fluctuations and even vibrations in return torque and return speed due to fluctuations in steering wheel speed and steering wheel angular acceleration, this invention requires correction of the steering wheel torque. The corrected steering wheel torque MR is obtained by subtracting the additional torque ME calculated above from the steering wheel torque M0 measured by the torque sensor. This effectively eliminates this problem and ensures that the corrected steering wheel torque MR used for calculation is closer to the actual torque applied to the steering wheel by the driver. In particular, it has a significant improvement in the return-to-center condition of the steering wheel when the driver has completely taken his hands off the wheel.

[0064] By indexing the corrected steering wheel torque MR, the corresponding torque gain coefficient KT can be found. The correspondence between the corrected steering wheel torque MR and the torque gain coefficient KT is as follows: Figure 4 .

[0065] The rate at which the torque gain coefficient KM decreases as the corrected steering wheel torque MR increases should be fast at first and then slow.

[0066] In the embodiments provided by this invention, during the return-to-center process, it is usually necessary to control the steering wheel speed to obtain a better evaluation of the steering wheel feel. Traditional return-to-center control, whether using lookup tables or PID / MPS control, does not limit the speed, thus easily leading to excessively fast return-to-center speeds in actual control. By establishing an index for the steering wheel speed Vr, the corresponding speed gain coefficient Kr can be found. In principle, the speed gain coefficient Kr should be between 0 and 1, but if the return-to-center speed is too fast at a certain speed, a gain coefficient exceeding 1 can be set. The correspondence between steering wheel speed Vr and speed gain coefficient Kr is shown below. Figure 5 .

[0067] As the steering wheel speed Vr increases, the speed gain coefficient initially remains constant, then gradually decreases to achieve a controllable return-to-center speed. During the return-to-center process, when the steering wheel speed Vr is low, the return-to-center speed control function does not control the return-to-center speed and does not reduce the requested return-to-center torque. When the steering wheel speed Vr is high during the return-to-center process, because the speed gain coefficient Kr decreases and is less than 1, it reduces the requested return-to-center torque, thus reducing the steering wheel speed Vr during return-to-center. The speed gain coefficient Kr should decrease at a rate that is slow at first and then fast as the steering wheel speed Vr increases.

[0068] The above embodiment is optimized to compensate for the suspension return-to-center characteristics during the steering wheel return-to-center process.

[0069] The vehicle's suspension design already takes into account some self-centering, meaning that due to the presence of the kingpin inclination angle and kingpin crowning angle, the vehicle itself has a certain steering self-centering function. The influence of the kingpin inclination angle on the vehicle's self-centering increases with vehicle speed, while the influence of the kingpin crowning angle on the vehicle's self-centering hardly changes with vehicle speed.

[0070] Since the self-centering effect caused by caster angle and kingpin inclination angle is difficult to calculate, a calibration method is used to determine it. Specifically, with the EPS system's active self-centering function disabled, the steering wheel torque required to maintain different angles at different vehicle speeds is measured, and this torque value is recorded as the mechanical self-centering torque under the current conditions. Calibration uses a three-dimensional table, creating a table indexed by vehicle speed V and the absolute value of the steering wheel angle θ, and recording the measured mechanical self-centering torque. The corresponding table is as follows:

[0071]

[0072] After the form is filled out through calibration, the vehicle speed V and the absolute value of the steering wheel angle θ are used in the subsequent calculation process to determine the self-centering torque that the vehicle can provide—the mechanical self-centering torque.

[0073] The self-aligning torque can also be calculated using the tire's magic formula:

[0074]

[0075] Where: X1=(α+Sh), α is the sideslip angle;

[0076] C: Curve shape factor, C0 is used when calculating the alignment torque: C=C0

[0077] D: Peak factor, representing the maximum value of the curve.

[0078] BCD: Torsional stiffness at the zero point of the restoring torque.

[0079] B: Stiffness factor:

[0080] Sh: Horizontal drift of the curve:

[0081] Sv: Vertical drift of the curve:

[0082] E: Curve curvature factor, representing the shape near the maximum value of the curve.

[0083]

[0084] By indexing vehicle speed V, the alignment compensation coefficient K can be found. The correspondence between vehicle speed V and alignment compensation coefficient K is shown below. Figure 6 .

[0085] Taking into account all the above calculations and the influence of the vehicle speed compensation coefficient, the final calculation formula for the requested control torque MF is as follows:

[0086]

[0087] The beneficial effects of the technical solution of this invention are as follows:

[0088] Zonal control function: By employing a zonal control strategy based on steering wheel angle (combining lookup table control and PID / MPS control), the problems of uneven return speed at large angles and insufficient return accuracy at small angles, as found in traditional single control methods, are solved. For example, in the large angle range (θ> A lookup table control is used to ensure a fast and uniform return-to-center speed; within a small angle range (θ≤... PID control is used to achieve precise homing to zero, avoiding the generation of residual homing angle and improving the user's operating experience.

[0089] Inertial torque estimation function: Calculates the additional torque M by measuring the steering wheel's moment of inertia J and combining it with the angular acceleration β. e This effectively eliminates the interference of the mechanical structure's rotational inertia on the return process, reduces fluctuations and vibrations in the return speed, and makes the return process smoother and more controllable.

[0090] Steering wheel torque correction function: Corrects steering wheel torque Mᵣ It eliminates the error in return torque caused by fluctuations in steering wheel speed, and significantly improves the stability of return control, especially when the driver has completely taken their hands off the wheel.

[0091] Speed ​​control function: based on steering wheel speed Dynamically adjust the speed gain coefficient The maximum speed during the return-to-center process is limited to avoid discomfort caused by excessive speed. At the same time, the gain coefficient is adjusted in segments to balance the response speed at low speeds and the smoothness at high speeds.

[0092] Mechanical self-centering compensation function: By calibrating the mechanical self-centering torque of the vehicle suspension system and combining it with a three-dimensional table of vehicle speed and steering wheel angle compensation, the robustness of traditional methods that ignore the vehicle's own self-centering characteristics is insufficient, thus enhancing the system's adaptability to different vehicle models.

[0093] Based on the same inventive concept, this invention provides an electric power steering active return-to-center control system for implementing the above method, comprising:

[0094] The zone control unit is used to perform zone control based on the steering wheel angle during the rotation of the vehicle's steering wheel to obtain the original requested torque;

[0095] The torque estimation unit is used to estimate the steering wheel inertial torque during the steering wheel return process;

[0096] The correction unit is used to calculate the corrected steering wheel torque from the original requested torque and steering wheel inertia torque, and to correct the steering wheel torque based on the corrected steering wheel torque.

[0097] The electric power steering active return-to-center control system provided by this invention first performs zoned control based on the steering wheel angle during the rotation of the vehicle's steering wheel to obtain the original requested torque. During the steering wheel return-to-center process, the steering wheel inertial torque is estimated. Then, the original requested torque and the steering wheel inertial torque are calculated to obtain the corrected steering wheel torque. The steering wheel torque is corrected based on the corrected steering wheel torque, eliminating the return-to-center torque error caused by steering wheel speed fluctuations. Especially when the driver has completely taken their hands off the wheel, the stability of the return-to-center control is significantly improved.

[0098] In one embodiment, the control system provided by the present invention further includes a speed control unit and a compensation unit.

[0099] The speed control unit is mainly used during the steering wheel return process. By establishing an index of the steering wheel speed, it finds the corresponding speed gain coefficient to control the steering wheel speed. It mainly limits the maximum speed during the return process to avoid discomfort caused by excessive speed. At the same time, by adjusting the gain coefficient in segments, it takes into account both the response speed at low speeds and the smoothness at high speeds.

[0100] The compensation unit is used to compensate for the suspension return to center during the steering wheel return process, which can ensure the robustness of the vehicle during the return process.

[0101] Based on the same inventive concept, embodiments of the present invention also provide an electronic device. Figure 8 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Figure 8 As shown, an embodiment of the present invention provides an electronic device including: one or more processors 101, a memory 102, and one or more I / O interfaces 103. The memory 102 stores one or more programs, which, when executed by the one or more processors, cause the one or more processors to implement any of the electric power steering active return-to-center control methods described in the above embodiments; the one or more I / O interfaces 103 are connected between the processor and the memory, configured to enable information interaction between the processor and the memory.

[0102] The processor 101 is a device with data processing capabilities, including but not limited to a central processing unit (CPU); the memory 102 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory (FLASH); the I / O interface (read / write interface) 103 is connected between the processor 101 and the memory 102, and can realize information interaction between the processor 101 and the memory 102, including but not limited to a data bus (Bus).

[0103] In some embodiments, the processor 101, memory 102, and I / O interface 103 are interconnected via bus 104, and thus connected to other components of the computing device.

[0104] In some embodiments, the one or more processors 101 include a field-programmable gate array.

[0105] This invention also provides a computer-readable medium. The computer-readable medium stores a computer program, which, when executed by a processor, implements the steps of any of the electric power steering active return-to-center control methods described in the above embodiments. The computer-readable storage medium may be volatile or non-volatile.

[0106] This invention also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code. When the computer-readable code is run in the processor of an electronic device, the processor in the electronic device executes the above-described electric power steering active return-to-center control method.

[0107] Those skilled in the art will understand that all or some of the steps, systems, and apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software can be distributed on a computer-readable storage medium, which may include computer storage media (or non-transitory media) and communication media (or transient media).

[0108] As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technologies, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable program instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0109] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0110] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0111] The computer program product described herein can be implemented specifically through hardware, software, or a combination thereof. In one alternative embodiment, the computer program product is specifically embodied in a computer storage medium; in another alternative embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0112] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0113] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0114] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0115] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0116] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A method for active return-to-center control of electric power steering, characterized in that, include: During the rotation of the vehicle's steering wheel, zone control is performed based on the steering wheel angle to obtain the original requested torque; Estimate the steering wheel's inertial torque during the steering wheel return process; The original requested torque and steering wheel inertia torque are calculated to obtain the corrected steering wheel torque, and the steering wheel torque is corrected based on the corrected steering wheel torque.

2. The method according to claim 1, characterized in that, The zone control based on steering wheel angle includes: The current steering wheel angle is read. When the steering wheel angle is higher than the preset threshold, lookup table control is used; when the steering wheel angle is lower than the preset threshold, PID control or MPS model predictive control is used.

3. The method according to claim 1, characterized in that, The estimation of the steering wheel inertial torque during the steering wheel return process includes: The moment of inertia of the part above the torque sensor is calculated by actual measurement. The angular acceleration is obtained by filtering the differential of the angular velocity read by the sensor. The additional torque generated under different angular accelerations is calculated based on the moment of inertia and angular acceleration.

4. The method according to claim 1, characterized in that, The step of calculating the corrected steering wheel torque from the original requested torque and steering wheel inertia torque, and then correcting the steering wheel torque based on the corrected steering wheel torque, includes: The corrected steering wheel torque is obtained by subtracting the calculated additional torque from the steering wheel torque measured by the torque sensor. The corresponding torque gain coefficient is then found by indexing the corrected steering wheel torque.

5. The method according to claim 1, characterized in that, The method further includes: During the steering wheel return process, an index is established for the steering wheel speed, and the corresponding speed gain coefficient is used to control the steering wheel speed.

6. The method according to claim 5, characterized in that, The method further includes: The suspension is compensated for during the steering wheel return-to-center process.

7. The method according to claim 6, characterized in that, The compensation for suspension return to center during steering wheel return to center includes: With the EPS system's active self-centering function turned off, measure the steering wheel torque required to maintain different angles at different vehicle speeds, and record this torque value as the mechanical self-centering torque under the current conditions.

8. An active return-to-center control system for electric power steering, characterized in that, For configuring the implementation of the method as described in any one of claims 1-7, comprising: The zone control unit is used to perform zone control based on the steering wheel angle during the rotation of the vehicle's steering wheel to obtain the original requested torque; The torque estimation unit is used to estimate the steering wheel inertial torque during the steering wheel return process; The correction unit is used to calculate the corrected steering wheel torque from the original requested torque and steering wheel inertia torque, and to correct the steering wheel torque based on the corrected steering wheel torque.

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in any one of claims 1 to 7.

10. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

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