Smooth control method, system, medium and equipment for rear wheel steering mode switching

Abstract

This invention provides a smooth control method, system, medium, and device for rear-wheel steering mode switching, belonging to the field of vehicle chassis electronic control technology. The method includes system state initialization; time accumulation and time reset; transition time anomaly protection; mode switching step detection and transition start; input update and transition state processing; state update and CANFD output. This method effectively suppresses abrupt angle changes caused by rear-wheel steering mode switching, outputting smooth, overshoot-free steering angle commands; and real-time tracking of dynamically changing target values ​​during the transition process, adapting to the needs of continuous mode switching.

Description

Technical Field

[0001] This invention relates to the field of vehicle chassis electronic control technology, and in particular to a smooth control method, system, medium, and device for rear wheel steering mode switching. Background Technology

[0002] Under the centralized controller OIB (Onboard Integrated Brain) architecture, the target rear wheel steering angle of the RWS system is calculated in parallel by multiple functional modules, including a low-speed small-radius steering module, a high-speed same-direction yaw module, a crab mode module, a HAD (Highly Automated Driving) autonomous driving module, a pre-stability control module, and a fault return-to-zero module. Each module independently calculates the target angle based on different control strategies and optimization objectives. When a mode switch occurs during vehicle operation (such as vehicle speed exceeding a threshold leading to a low-speed / high-speed mode switch, driver activation of crab mode, autonomous driving system takeover, stability control system intervention, or system fault triggering return to zero), the target rear wheel steering angle calculated by different modes often differs significantly. In the existing technology, the OIB directly sends the arbitrated target angle to the AKC (Active Kinematics Control) actuator via the CANFD (CAN Flexible Data-rate) bus, causing the rear wheel steering angle to jump instantaneously. This results in current surges in the AKC motor, impact loads on the mechanical transmission mechanism, and sudden changes in vehicle yaw rate, which seriously affect ride comfort and driving safety.

[0003] Some existing technologies employ a fixed-endpoint interpolation transition method, locking the transition endpoint upon detecting a mode switch. However, during the transition, the new mode typically continues to run and calculates a new target angle based on the updated vehicle state (e.g., HAD mode continuously updates the target turning angle based on the real-time planned trajectory, and pre-stabilization control dynamically adjusts the correction amount based on the real-time yaw state). The fixed-endpoint scheme causes the output during the transition to fail to track the latest calculation results of the new mode; the target angle sent from the OIB to the AKC via CANFD remains a locked historical value, resulting in significant response lag. This lag is particularly pronounced if the transition time is long, potentially missing the optimal control opportunity and affecting the accuracy of driving trajectory tracking and the timeliness of stability control.

[0004] In real-world use, vehicles may be driven continuously or powered on for several hours or even longer (e.g., long-distance highway driving, forgetting to turn off the power and lock the car for a week after returning home). If the smooth transition module within the OIB adopts an absolute time accumulation strategy, when using 32-bit single-precision floating-point numbers to represent time, the accumulated time exceeds approximately 2.78 hours (10^64 hours).4 After a certain number of seconds, continuing to accumulate a fixed step size will result in the step size being rounded off due to insufficient floating-point precision, and the time will no longer increase. At this point, the normalized time τ in the transition calculation cannot be updated correctly, the smoothing function is lost, and the step instruction during mode switching will be directly sent to the AKC actuator via CANFD, posing a safety risk. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a smooth control method, system, medium and device for rear wheel steering mode switching.

[0006] In a first aspect, embodiments of the present invention provide a smooth control method for rear-wheel steering mode switching, comprising the following steps:

[0007] S100, System state initialization;

[0008] S200, Time Accumulation and Time Reset;

[0009] S300, Transition Time Abnormal Protection;

[0010] S400, mode switching step detection and transition start;

[0011] S500, Input Update and Transition State Handling;

[0012] S600, Status Update and CANFD Output.

[0013] Further, step S100 includes: on the first call after the OIB is powered on or software reset, initializing the following persistent variables: the transition state flag is set to non-transition state, the transition start time and the system cumulative running time are both initialized to zero, the transition start output, the transition end output, the previous moment output and the previous moment input are all initialized to the target rear wheel angle of the current mode arbitration output, the time upper limit parameter is set, and the time reset reference is set.

[0014] Further, step S200 includes: performing time accumulation update and time reset judgment sequentially in each control cycle; time accumulation update includes: increasing the system's cumulative running time by a fixed step; time reset judgment includes: if the system's cumulative running time exceeds the time limit, subtracting the time reset benchmark from the current cumulative running time, and simultaneously subtracting the same time reset benchmark from the transition start time.

[0015] Further, step S300 includes: if the transition time is less than or equal to zero, directly output the actual angle output by the CANFD bus at the previous moment, update the historical state record, and return to the current transition state.

[0016] Further, step S400 includes: determining whether the current state is a non-transitional state; if it is a non-transitional state, comparing the absolute value of the difference between the current target angle and the target angle at the previous moment; if the difference exceeds a preset step detection threshold, determining that a mode switch has occurred and starting a new transition process: setting the transition state flag to a transitional state, recording the current moment as the transition start moment, using the actual output angle at the previous moment as the transition start point, and using the current target angle as the transition end point.

[0017] Further, step S500 includes: updating the input record from the previous moment to the current target angle;

[0018] If the system is currently in a transition state, the following sub-steps are executed sequentially: Update the transition endpoint to the target angle calculated by the latest mode; divide the difference between the current cumulative running time and the transition start time by the transition time to obtain the normalized time; if the normalized time is greater than or equal to 1 minus the difference of the small tolerance value, set the normalized time to 1 and reset the transition state flag to the non-transition state, indicating that the transition is complete; if the normalized time is less than zero, set the normalized time to zero; when the normalized time reaches 1, the transition is complete, the transition state flag is set to the non-transition state, and the system exits the transition state; calculate the interpolation factor based on the normalized time using a cubic Bézier curve with zero starting and ending velocities, and then use this interpolation factor to perform linear interpolation on the transition start and transition endpoint to obtain the smoothed output angle;

[0019] If the current state is not in transition, the target angle of the current mode will be output directly.

[0020] Further, step S600 includes: updating the output record of the previous moment to the current smoothed output angle, outputting the current transition state flag, packaging the smoothed rear wheel target steering angle and the transition state flag into a CANFD message, and sending it to the vehicle network through the CANFD bus.

[0021] Secondly, embodiments of the present invention provide a smooth control system for rear-wheel steering mode switching, used to implement the method described above, including:

[0022] An initialization unit is used for system state initialization.

[0023] The accumulation and reset unit is used for time accumulation and time reset;

[0024] Protection unit, used for transition time anomaly protection;

[0025] The detection unit is used for mode switching step detection and transition start-up;

[0026] The update unit is used for input update and transition state processing;

[0027] Output unit, used for status updates and CANFD output.

[0028] Thirdly, embodiments of the present invention provide an electronic device, comprising:

[0029] One or more processors;

[0030] Memory, used to store one or more programs;

[0031] When the one or more programs are executed by the one or more processors, the one or more processors perform the method as described above.

[0032] Fourthly, embodiments of the present invention provide a computer-readable medium on which a computer program is stored, the computer program being executed by a processor to implement the steps in the method described above.

[0033] The present invention provides a smooth control method, system, medium, and device for rear-wheel steering mode switching. Through system state initialization; time accumulation and time reset; transition time anomaly protection; mode switching step detection and transition start; input update and transition state processing; state update and CANFD output, it can effectively suppress the angle abrupt change caused by rear-wheel steering mode switching and output smooth, overshoot-free steering angle commands. During the transition process, it tracks the dynamically changing target value in real time to adapt to the needs of continuous mode switching. Attached Figure Description

[0034] Figure 1 A flowchart illustrating a smooth control method for rear wheel steering mode switching provided in an embodiment of the present invention;

[0035] Figure 2 A flowchart illustrating a smooth control method for rear-wheel steering mode switching provided in an embodiment of the present invention;

[0036] Figure 3 The actual waveform diagram obtained by running a smooth control method in a typical mode switching scenario for a rear-wheel steering system equipped with a central domain controller;

[0037] Figure 4 A structural block diagram of a smooth control system for rear wheel steering mode switching provided in an embodiment of the present invention;

[0038] Figure 5 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0039] 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.

[0040] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0041] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0042] 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.

[0043] 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.

[0044] This invention provides a smooth control method for rear-wheel steering mode switching. This method is deployed within the RWS control function module of the central domain centralized controller OIB, located between the mode arbitration module and the CANFD communication output interface. (See reference...) Figure 1 As shown, the method includes the following steps:

[0045] S100, System state initialization.

[0046] In one embodiment, see Figure 2As shown, this includes: on the first call after OIB power-on or software reset, initializing the following persistent variables: the transition state flag is set to non-transition state, the transition start time and the system cumulative running time are both initialized to zero, the transition start output, transition end output, previous moment output and previous moment input are all initialized to the target rear wheel angle of the current mode arbitration output, the time upper limit parameter is set, and the time reset reference is set.

[0047] Specifically, the transition state flag Smooth_ActiveSt is set to false, indicating that the initial state is non-transitional, i.e., Smooth_ActiveSt = false; the transition start time t_start and the system cumulative running time simTime are both initialized to zero, i.e., t_start = single(0) and simTime = single(0); the transition start output y_start, the transition end output y_end, the previous output y_prev, and the previous input u_prev are all initialized to the target rear wheel angle u of the current mode arbitration output, i.e., y_start = u, y_end = u, y_prev = u, u_prev = u; the time limit parameter T_MAX is set to 10000 seconds, i.e., T_MAX = single(1e4) (approximately 2.78 hours); the time reset base T_BASE is set to 5000 seconds, i.e., T_BASE = single(5e3) (approximately 1.39 hours).

[0048] The target rear wheel steering angle u output by the current mode arbitration comes from the RWS mode arbitration module.

[0049] All time-related variables are stored as single-precision floating-point numbers to accommodate the memory and computational resource limitations of the OIB.

[0050] S200, Time Accumulation and Time Reset.

[0051] In one embodiment, see Figure 2 As shown, it includes: each control cycle sequentially performs time accumulation update and time reset judgment; time accumulation update includes: increasing the system's cumulative running time by a fixed step; time reset judgment includes: if the system's cumulative running time exceeds the time limit, then the current cumulative running time is subtracted from the time reset benchmark, and the transition start time is also subtracted from the same time reset benchmark at the same time.

[0052] Specifically, the execution time of each control cycle is cumulatively updated: the cumulative system running time simTime is increased by a fixed step size fixed_step. This fixed step size fixed_step is consistent with the OIB task scheduling cycle. In this embodiment of the invention, it is set to 10 milliseconds, that is, simTime = simTime + fixed_step.

[0053] Then, a time reset judgment is performed: if the system's cumulative running time simTime exceeds the time limit T_MAX, the current cumulative running time is subtracted from the time reset benchmark T_BASE, and the transition start time t_start is also subtracted from the same time reset benchmark. That is, if simTime > T_MAX: simTime = simTime - T_BASE, t_start = t_start - T_BASE.

[0054] The technical principle is that Bessel interpolation calculations rely solely on the difference between the current cumulative running time and the transition start time (simTime - t_start). By subtracting the same value from both simultaneously, this difference remains strictly constant, thus the normalized time calculation result is unaffected. The time reset baseline T_BASE is chosen to be less than the time upper limit (T_BASE < T_MAX) and much larger than the typical transition time (T_trans, typically 0.5 to 2 seconds), ensuring that the reset operation does not interfere with the ongoing transition process.

[0055] This invention employs a time reset mechanism. When the accumulated running time exceeds the upper limit, a fixed reference is subtracted synchronously from the transition start time. Bessel interpolation relies solely on the difference between the two values ​​and remains unchanged after synchronization, ensuring uninterrupted transition continuity. It supports continuous scenarios lasting tens of hours, such as taxis, ride-hailing services, long-distance freight, and situations where users forget to turn off the power. The computational overhead is extremely low, guaranteeing the stability of CANFD communication.

[0056] S300, Transition Time Abnormal Protection.

[0057] In one embodiment, see Figure 2 As shown, this includes: if the transition time is less than or equal to zero, directly output the actual angle output by the CANFD bus at the previous moment, update the historical state record, and return the current transition state.

[0058] Specifically, before performing the transition calculation, the validity of the transition time parameter is checked. This mechanism ensures that when the transition time parameter is abnormal, the system operates in a safe degraded mode, maintaining the stable output of the previous moment, avoiding numerical abnormalities caused by division operations, and ensuring the continuity of communication between CDC (Continuous Damping Control) and CANFD. If the transition time is less than or equal to zero, the actual angle output by the CANFD bus at the previous moment (denoted as TargetAg_prev) is directly output, the historical state record is updated, and the current transition state is returned. That is, if T_trans ≤ single(0): y = TargetAg_prev, y_prev = y, u_prev = TargetAg_prev, Smooth_ActiveSt_out = Smooth_ActiveSt, return.

[0059] The actual angle TargetAg_prev output by the CANFD bus at the previous moment is the smoothed target rotation angle that was sent to the AKC actuator via CANFD in the previous control cycle.

[0060] S400, mode switching step detection and transition start.

[0061] In one embodiment, see Figure 2 As shown, it includes: determining whether the current state is a non-transitional state; if it is a non-transitional state, comparing the absolute value of the difference between the current target angle and the target angle at the previous moment; if the difference exceeds the preset step detection threshold, determining that a mode switch has occurred and starting a new transition process: setting the transition state flag to the transition state, recording the current moment as the transition start moment, taking the actual output angle at the previous moment as the transition start point, and taking the current target angle as the transition end point.

[0062] Specifically, it determines whether the current state is non-transitional. If it is not, it compares the absolute value of the difference between the current target angle and the target angle at the previous moment. If this difference exceeds the preset step detection threshold, it determines that a mode switch has occurred and initiates a new transition process: the transition state flag is set to true, the current moment is recorded as the transition start moment, the actual output angle at the previous moment is taken as the transition start point, and the current target angle is taken as the transition end point. The step detection threshold is used to distinguish between normal fine-tuning of the target angle within a mode and a large abrupt change caused by a mode switch. The calibration of this threshold needs to consider the maximum normal difference between modes and the system noise level. That is, if Smooth_ActiveSt == false; if abs(u - u_prev) > threshold: Smooth_ActiveSt = true, t_start = simTime, y_start = y_prev, y_end = u.

[0063] This invention utilizes threshold detection to initiate a smooth transition only for abrupt mode switching exceeding a threshold; continuous changes within the normal mode are directly and quickly tracked and transmitted in real time via CANFD. This avoids the lag introduced by low-pass filtering on all changes, balancing response speed and smoothness, ensuring the AKC responds quickly to driver operations, and providing sufficient protection during mode switching.

[0064] S500, Input Update and Transition State Handling.

[0065] In one embodiment, see Figure 2 As shown, this includes: updating the input record from the previous moment to the current target angle;

[0066] If the system is currently in a transition state, the following sub-steps are executed sequentially: Update the transition endpoint to the target angle calculated by the latest mode; divide the difference between the current cumulative running time and the transition start time by the transition time to obtain the normalized time; if the normalized time is greater than or equal to 1 minus the difference of the small tolerance value, set the normalized time to 1 and reset the transition state flag to the non-transition state, indicating that the transition is complete; if the normalized time is less than zero, set the normalized time to zero; when the normalized time reaches 1, the transition is complete, the transition state flag is set to the non-transition state, and the system exits the transition state; calculate the interpolation factor based on the normalized time using a cubic Bézier curve with zero starting and ending velocities, and then use this interpolation factor to perform linear interpolation on the transition start and transition endpoint to obtain the smoothed output angle;

[0067] If the current state is not in transition, the target angle of the current mode will be output directly.

[0068] Specifically, step S500 includes:

[0069] Update the input record from the previous moment to the current target angle, i.e., u_prev = u;

[0070] If the current state is a transition state (Smooth_ActiveSt == true), then the following sub-steps are executed sequentially:

[0071] S510, Real-time Endpoint Update

[0072] Update the transition endpoint to the target angle calculated by the latest model, i.e., y_end = u;

[0073] This step is one of the core innovations of this invention. During each control cycle of the transition, the endpoint is updated in real time to the latest target angle, rather than being locked at the start of the transition. This allows the OIB to continuously track real-time target changes in each mode during the transition, ensuring that the commands sent from CANFD to AKC are always the latest valid values.

[0074] S520, Calculate normalized time

[0075] The normalized time tau is obtained by dividing the difference between the current cumulative running time and the transition start time by the transition time, i.e., tau = (simTime - t_start) / T_trans;

[0076] Boundary limiting is applied to the normalized time: if the normalized time is greater than or equal to 1 minus the small tolerance value, the normalized time is set to 1 and the transition state flag is reset to false, indicating that the transition is complete; if the normalized time is less than zero, the normalized time is set to zero; that is, if tau >= single(1 - 1e-5): tau = single(1), Smooth_ActiveSt = false; if tau < single(0): tau = single(0);

[0077] When the normalized time tau reaches 1, the transition is complete, the Smooth_ActiveSt flag is set to false, and the system exits the transition state.

[0078] S530, Bessel interpolation calculation

[0079] The interpolation factor is calculated using a simplified form of a cubic Bézier curve with zero starting and ending velocities: the square of the normalized time multiplied by 3 minus twice the normalized time. This interpolation factor is then used to linearly interpolate the transition start and end points to obtain the smoothed output angle y. That is, factor = tau * tau * (single(3) - single(2) *tau), y = y_start * (single(1) - factor) + y_end * factor.

[0080] The interpolation factor takes a value of zero when the normalized time tau is zero and a value of 1 when the normalized time tau is 1, and its first derivative is zero at both ends. This means that the rate of change of the rear wheel steering angle is zero at both the start and end of the transition, achieving a soft start and soft stop with zero speed at the endpoints.

[0081] If the current state is not in transition (Smooth_ActiveSt == false), the target angle of the current mode is directly output as the smoothed output angle, i.e., y = u.

[0082] This invention utilizes step detection to trigger Bezier interpolation, transforming abrupt angular changes into continuous, smooth variations over a fixed duration. For example, when switching to crab mode, the rear wheels transition smoothly, almost imperceptibly to passengers, significantly improving ride comfort.

[0083] Through a real-time endpoint update mechanism, the endpoint is updated to the latest target angle in each cycle during the transition. Regardless of HAD trajectory adjustment or pre-stabilization correction of the turning angle, it can directly and smoothly approach the latest target without interrupting the transition or waiting for it to end, avoiding output jitter and reciprocating motion, and significantly improving dynamic response and tracking accuracy.

[0084] S600, Status Update and CANFD Output.

[0085] In one embodiment, see Figure 2 As shown, the process includes: updating the previous output record to the current smoothed output angle, outputting the current transition state flag, packaging the smoothed rear wheel target steering angle and the transition state flag into a CANFD message, and sending it to the vehicle network via the CANFD bus.

[0086] Specifically, step S600 includes:

[0087] Update the output record from the previous time step to the current smoothed output angle, i.e., y_prev = y;

[0088] Output the current transition state flag, Smooth_ActiveSt_out = Smooth_ActiveSt;

[0089] The smoothed rear wheel target steering angle and transition status flag are packaged into a CANFD message and sent to the vehicle network via the CANFD bus.

[0090] The smoothed target rotation angle y is sent via CANFD data frames as a tracking command for the AKC actuator position control loop; the transition state flag output Smooth_ActiveSt_out is available for reading by other functional modules within the OIB and other nodes on the CANFD network.

[0091] This invention, through system state initialization; time accumulation and time reset; transition time anomaly protection; mode switching step detection and transition start; input update and transition state processing; state update and CANFD output, can effectively suppress the sudden angle change caused by rear wheel steering mode switching, output smooth, overshoot-free steering angle commands; and track dynamically changing target values ​​in real time during the transition process to adapt to the needs of continuous mode switching.

[0092] Verification Example:

[0093] This embodiment is based on a rear-wheel steering system equipped with a central domain controller (OIB). The actual waveforms obtained by running this method under a typical mode switching scenario are shown below. Figure 3 .

[0094] 1. Test conditions

[0095] Control cycle (fixed step size): 10 ms; Step detection threshold: 4°; Transition time T_trans: 1.5 s; Time limit T_MAX: 10000 s; Time reset reference T_BASE: 5000 s; Input signal source: Mode arbitration module (simulating the transition from zero-return mode to main mode, i.e., transitioning from 0deg to the main mode dynamic target value); Output signal destination: AKC actuator (via CANFD bus).

[0096] 2. Comparison of input signal and output waveform

[0097] like Figure 3 As shown, the blue curve represents the input signal before smoothing received by the module of this method (i.e., the target rear wheel steering angle directly output by the mode arbitration module), and the red curve represents the output signal after smoothing by the method of this invention (i.e., the final steering angle command sent to the AKC actuator via CANFD).

[0098] 3. Waveform Analysis

[0099] 3.1 Smooth Response to Step Input

[0100] In the time interval t = 2 s shown in the figure, the input signal (blue line) jumps instantaneously from 0° to 10° (simulating the backspin-off state switching to small-radius steering mode when the steering wheel is turned all the way). It can be seen that this method immediately initiates a smooth transition after detecting that the jump amplitude (10°) exceeds the threshold (4°). The output signal (red line) does not follow the input jump, but starts from 0° before the jump and changes smoothly over a preset transition time of 1.5 s, without overshoot or oscillation. This achieves soft start and soft stop.

[0101] 3.2 Dynamic Target Updates During the Transition Process

[0102] In the time interval t = 2 s - 3.5 s in the figure, the input signal (blue line) continues to change before the transition is complete. This shows that, according to step 2.5.1, the algorithm updates the endpoint y_end in real time without interrupting or restarting the transition, but rather continues to move smoothly from the current output value to the new endpoint. The red line remains smooth throughout the entire process, without any abrupt changes or discontinuities in angular velocity, demonstrating the superiority of this method under continuously changing input values.

[0103] 3.3 Straight-through behavior without transitions

[0104] In the time interval t = 4 s - 10 s in the figure, the input signal (blue line) changes smoothly (amplitude change is less than the threshold). This method detects that |u - u_prev| ≤ threshold, therefore maintaining a non-transitional state, and the output (red line) directly follows the input (blue line), completely coinciding. This shows that this method does not introduce unnecessary delays or distortions when smoothing is not required.

[0105] The present invention also provides a smooth control system for rear-wheel steering mode switching, for implementing the method described above, see reference. Figure 4 As shown, the system includes:

[0106] Initialization unit 110 is used for system state initialization;

[0107] Accumulation and reset unit 120 is used for time accumulation and time reset;

[0108] Protection unit 130 is used for transition time abnormal protection;

[0109] Detection unit 140 is used for mode switching step detection and transition start;

[0110] Update unit 150 is used for input update and transition state processing;

[0111] Output unit 160 is used for status updates and CANFD output.

[0112] This invention also provides an electronic device, see below. Figure 5 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, enable the one or more processors to implement a smooth control method for switching rear-wheel steering modes as described in any of 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.

[0113] 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).

[0114] 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.

[0115] In some embodiments, the one or more processors 101 include a field-programmable gate array.

[0116] 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 in any of the rear-wheel steering mode switching smooth control methods described in the above embodiments. The computer-readable storage medium may be volatile or non-volatile.

[0117] 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).

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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 smooth control method for rear-wheel steering mode switching, characterized in that, Includes the following steps: S100, System state initialization; S200, Time Accumulation and Time Reset; S300, Transition Time Abnormal Protection; S400, mode switching step detection and transition start; S500, Input Update and Transition State Handling; S600, Status Update and CANFD Output.

2. The method according to claim 1, characterized in that, Step S100 includes: on the first call after the OIB is powered on or software reset, initializing the following persistent variables: the transition state flag is set to non-transition state, the transition start time and the system cumulative running time are both initialized to zero, the transition start output, the transition end output, the previous moment output and the previous moment input are all initialized to the target rear wheel angle of the current mode arbitration output, the time upper limit parameter is set, and the time reset reference is set.

3. The method according to claim 2, characterized in that, Step S200 includes: performing time accumulation update and time reset judgment sequentially in each control cycle; time accumulation update includes: increasing the system's cumulative running time by a fixed step; time reset judgment includes: if the system's cumulative running time exceeds the time limit, subtracting the time reset benchmark from the current cumulative running time, and simultaneously subtracting the same time reset benchmark from the transition start time.

4. The method according to claim 3, characterized in that, Step S300 includes: if the transition time is less than or equal to zero, directly output the actual angle output by the CANFD bus at the previous moment, update the historical state record, and return to the current transition state.

5. The method according to claim 4, characterized in that, Step S400 includes: determining whether the current state is a non-transitional state; if it is a non-transitional state, comparing the absolute value of the difference between the current target angle and the target angle at the previous moment; if the difference exceeds a preset step detection threshold, determining that a mode switch has occurred and starting a new transition process: setting the transition state flag to a transitional state, recording the current moment as the transition start moment, using the actual output angle at the previous moment as the transition start point, and using the current target angle as the transition end point.

6. The method according to claim 5, characterized in that, Step S500 includes: updating the input record from the previous moment to the current target angle; If the system is currently in a transition state, the following sub-steps are executed sequentially: Update the transition endpoint to the target angle calculated by the latest mode; divide the difference between the current cumulative running time and the transition start time by the transition time to obtain the normalized time; if the normalized time is greater than or equal to 1 minus the difference of the small tolerance value, set the normalized time to 1 and reset the transition state flag to the non-transition state, indicating that the transition is complete; if the normalized time is less than zero, set the normalized time to zero; when the normalized time reaches 1, the transition is complete, the transition state flag is set to the non-transition state, and the system exits the transition state; calculate the interpolation factor based on the normalized time using a cubic Bézier curve with zero starting and ending velocities, and then use this interpolation factor to perform linear interpolation on the transition start and transition endpoint to obtain the smoothed output angle; If the current state is not in transition, the target angle of the current mode will be output directly.

7. The method according to claim 6, characterized in that, Step S600 includes: updating the output record of the previous moment to the current smoothed output angle, outputting the current transition state flag, packaging the smoothed rear wheel target steering angle and the transition state flag into a CANFD message, and sending it to the vehicle network through the CANFD bus.

8. A smooth control system for rear-wheel steering mode switching, used to implement the method as described in any one of claims 1 to 7, characterized in that, include: An initialization unit is used for system state initialization. The accumulation and reset unit is used for time accumulation and time reset; Protection unit, used for transition time anomaly protection; The detection unit is used for mode switching step detection and transition start-up; The update unit is used for input update and transition state processing; Output unit, used for status updates and CANFD output.

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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