EPS steering acceleration control method and storage medium

Abstract

The invention discloses an EPS steering acceleration control method. The method comprises the steps that EPS steering acceleration related parameters are obtained from a vehicle-mounted bus; the working state of a steering motor is recognized according to the EPS steering acceleration related parameters; if the motor is in an abnormal state, executing a safety protection strategy; if the motor is in a normal state, executing a hand feeling improving strategy; the safety protection strategy comprises the steps that in an abnormal state, the abnormal state of the motor is divided into different fault levels according to the number of times of natural vibration, the different fault levels correspond to different assistance reducing strategies, the abnormal state of the motor is monitored in real time, and fault switching is conducted; the hand feeling improvement strategy comprises the steps of dividing a driving condition, monitoring EPS steering acceleration related parameters in real time, and identifying a current driving condition; and respectively calculating acceleration compensation torques under different driving working conditions, and selecting corresponding compensation torques according to the currently identified working conditions. According to the invention, full-period safety protection and full-working-condition hand feeling improvement of the EPS system can be realized at the same time.

Description

Technical Field

[0001] This invention relates to the automotive field, and in particular to an EPS steering acceleration control method and storage medium. Background Technology

[0002] As a core component of vehicle steering control, the electric power steering (EPS) system directly affects driving feel and driving safety. During EPS operation, the acceleration of the steering system not only reflects the force and motion trend of the system, serving as a key basis for judging the state of a specific system, but also directly affects driving feel due to system inertia. Especially in scenarios such as rapid turnarounds, drastic changes in acceleration can cause fluctuations in feel, requiring inertial compensation forces to balance this effect.

[0003] During the development and debugging phase of EPS (Electrical Power Steering), adjustments are required across multiple stages, including hardware selection, software algorithm iteration, and parameter matching. However, during this process, issues such as hardware performance defects, imperfect algorithm logic, or insufficient parameter adaptability can easily lead to EPS system instability. This manifests as unexpected motor vibration or shaking, or abnormal vibration triggered by external stimuli (such as road bumps or impacts). Such anomalies can not only cause discomfort or even injury to the driver's hands but also accelerate the wear and tear of mechanical components in the steering system (such as racks and gears) and the aging and damage of circuit components. If the vehicle is in motion and the vibration is severe, it can further disrupt steering control stability, directly threatening the safety of the vehicle and its occupants. Therefore, accurately identifying abnormal states such as motor vibration and implementing effective safety protection strategies has become a core issue that urgently needs to be addressed during the EPS development and debugging phase. The accurate acquisition and analysis of the motor acceleration signal, as a key input for vibration identification, is particularly important.

[0004] During the user phase of EPS, the requirements for acceleration control vary significantly under different driving conditions: When driving on normal roads, at low speeds, the system inertia needs to be reduced to improve steering ease, while at high speeds, the system inertia needs to be increased to ensure steering stability and avoid "floating". When driving on bad roads (such as gravel roads and potholes), road impact is the main cause of acceleration changes. Acceleration compensation is needed to counteract the impact interference and reduce the driver's grip burden on the steering wheel. When driving on low-friction surfaces (such as snow or ice), the road surface friction is greatly reduced, which reduces the load on the rack end of the steering system. This can make the driving feel too light and floaty. Acceleration compensation is needed to increase the inertia to maintain a consistent feel.

[0005] However, existing EPS control schemes do not employ differentiated acceleration control logic for the aforementioned different operating conditions, nor do they adopt a uniform inertia compensation strategy. This design flaw results in the compensation force being unable to adapt to different road conditions: for example, using the same compensation parameters as normal road conditions on low-friction surfaces exacerbates the problem of a light and unstable feel; in bad road scenarios, it cannot specifically resist impacts, increasing driver fatigue, ultimately leading to insufficient stability and consistency of driving feel under all operating conditions, making it difficult to meet the needs of diverse driving scenarios.

[0006] In summary, current EPS systems have significant shortcomings in terms of safety protection during the development and debugging phase, as well as in terms of adaptability to operating conditions and control precision during user use. There is an urgent need for a steering acceleration control solution that can cover the entire product lifecycle of EPS while taking into account abnormal condition protection and multi-condition feel optimization. Summary of the Invention

[0007] The summary of this invention introduces a series of simplified concepts, all of which are simplifications of existing technologies in the field, and will be further explained in detail in the detailed description section. This summary is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0008] The technical problem to be solved by the present invention is to provide an EPS steering acceleration control method that can simultaneously achieve full-cycle safety protection of EPS system (real-time identification of abnormal motor vibration and execution of graded power assist reduction strategy) and full-condition feel improvement (differentiating between normal / bumpy / low-adhesion road conditions and applying differentiated acceleration compensation).

[0009] To solve the above-mentioned technical problems, the present invention provides an EPS steering acceleration control method, comprising the following steps: Obtain EPS steering acceleration related parameters from the vehicle's onboard bus; Identify the working status of the steering motor based on EPS steering acceleration-related parameters; If the motor is in an abnormal state, a safety protection strategy will be implemented; if the motor is in a normal state, a feel enhancement strategy will be implemented. The safety protection strategy includes: in abnormal conditions, classifying the abnormal state of the motor into different fault levels according to the number of self-oscillations, with different fault levels corresponding to different assist reduction strategies, and monitoring the abnormal state of the motor in real time and switching faults accordingly. The strategies for improving the feel include: Divide driving conditions, monitor EPS steering acceleration parameters in real time, and identify the current driving condition; Calculate the acceleration compensation torque for different driving conditions, and select the corresponding compensation torque based on the currently identified condition.

[0010] Preferably, a further improvement to the EPS steering acceleration control method includes identifying the steering motor's operating state, including: Initialize the motor status to normal. When the steering wheel speed and motor rotor acceleration repeatedly change beyond a set threshold within a set time range, it is determined that the steering system is vibrating. When vibration occurs, the system determines whether the vibration is caused by the motor's self-vibration based on the vehicle speed and the magnitude and range of the rack load force. If so, it is considered an abnormal state; otherwise, it is considered a normal state. When the motor state switches, a hysteresis condition is set to prevent repeated switching near the judgment threshold.

[0011] Preferably, in a further improved EPS steering acceleration control method, the fault level classification and corresponding power assist reduction strategy in the safety protection strategy are as follows: Fault level A: The number of self-oscillations is greater than the set number N1 and less than the set number N2. The EPS works normally and issues an early warning, and can recover to normal. Fault level B: The number of self-oscillations is greater than the set number N2 and less than the set number N3. The EPS reduces the boost output, but can recover to normal. Fault level C: The number of self-oscillations is greater than the set number N3, the EPS reduces the boost output, and can return to normal. When the number of motor self-oscillations increases or decreases, it can switch between fault levels A, B, C and normal mode; Where N1, N2, and N3 are specified numbers of times.

[0012] Preferably, the EPS steering acceleration control method is further improved by identifying driving conditions in the following manner; Normal road conditions: This is the default setting after initialization. It exits to normal road conditions when the conditions for bumpy road conditions and low-adhesion road conditions are met. Condition 1: Within the specified angle range Within, the rack load during steering reaches a specified time threshold. The change within exceeds the set threshold. The counter increments by one when the set time is reached. Inside, the counter count exceeds And the maximum load on the rack exceeds the set threshold. If so, it is determined that the road is bumpy; Condition 2: When at the set time Within a specified time threshold, the rack load... The change within is less than or equal to If condition 3 is not met, then normal road conditions will be entered; Condition 3: Calculate the normal rack and pinion load based on the angle, hand force, and motor assist by referring to a table. The correction factor is obtained by looking up the speed table. When the rack is loaded Condition 1 must be met: When the timer starts counting down, the duration exceeds the specified time. If so, it is determined that the road has entered a low-adjacent condition; Condition 4: When the rack is under load Condition 2 is met: When the timer starts, the duration exceeds the specified time. If the condition is not met, then the vehicle is deemed to have exited the low-adjacent road condition and is not in condition 1, then it enters the normal road condition.

[0013] Preferred setting of hysteresis interval In the entry and exit judgment of bumpy road conditions and low-adhesion road conditions, anti-rebound and hysteresis strategies are set.

[0014] Preferably, the EPS steering acceleration control method is further improved by calculating the acceleration compensation torque in the following ways: Under normal road conditions, the formula for calculating acceleration compensation is: ; For acceleration compensation torque under normal road conditions, This is the acceleration compensation gain coefficient under normal road conditions. This is the turning acceleration; The formula for calculating acceleration compensation torque under bumpy road conditions is: ; Torque compensation for acceleration under bumpy road conditions. This is the acceleration compensation gain coefficient under bumpy road conditions. This is the turning acceleration; The formula for calculating acceleration compensation under low-adjacent road conditions is as follows: ; For acceleration compensation torque under low-adhesion road conditions, This refers to the acceleration compensation gain coefficient under low-adhesion road conditions. This refers to the turning acceleration.

[0015] The acceleration compensation gain coefficient under different operating conditions can be calculated by looking up a table.

[0016] Preferably, in a further improvement to the EPS steering acceleration control method, when the compensation torque switches from one operating condition to another, the compensation torque needs to be limited according to a set gradient. Perform torque switching.

[0017] Preferably, the EPS steering acceleration control method is further improved, and the EPS steering acceleration related parameters include: vehicle speed, steering wheel torque and angle signal, motor torque, angle, motor speed, motor acceleration signal, steering acceleration signal, and rack force signal.

[0018] Preferably, the EPS steering acceleration control method is further improved by performing validity verification and filtering on the EPS steering acceleration related parameters, then differentiating and filtering the steering wheel angle to obtain the steering wheel speed, and differentiating and smoothing the motor speed to obtain the motor rotor acceleration.

[0019] Preferably, in a further improvement to the EPS steering acceleration control method, the criteria for determining abnormal motor conditions are as follows: The first direction of the steering wheel is negative, and the second direction is positive; the first direction of the engine speed is negative, and the second direction is positive. When the positive acceleration of the motor rotor exceeds the set threshold, At the set time Inside, the rotor's reverse acceleration also exceeded the set threshold. And at the set time Inside, the rotor's positive acceleration was detected once again to exceed the set threshold. This happened repeatedly more than the set number of times. Then determine the motor's natural vibration condition. True; Simultaneously monitor steering wheel speed, rack force, and vehicle speed. When the steering wheel speed reaches a set time... Within, exceeding the set threshold Repeated jumps occur that match the rotor acceleration, and the rack force is less than the threshold obtained by looking up the table based on the vehicle speed. Then determine the motor's natural vibration condition. True; The default state is normal. The following conditions must be met: ; If the steering motor is determined to be disengaged from control, causing unexpected vibrations, the motor's state changes from normal to abnormal. When the above conditions are no longer met, a timer starts, and the timer continues until the set time is exceeded. If the above conditions are not met within the time limit, the motor state will change from abnormal state to normal state.

[0020] The present invention provides a computer-readable storage medium having a computer program stored therein, which, when executed, is used to implement the steps of any of the above-described EPS steering acceleration control methods.

[0021] During the development and debugging phase of electric power steering (EPS) systems, abnormal states such as unexpected self-vibration and shaking of the motor may occur due to hardware problems, immature algorithms, or incompatible parameters. These abnormal states can easily lead to driver injury, damage to system components, and even affect the safety of vehicles and the lives and property of people. Existing technologies lack targeted abnormal identification and safety protection strategies.

[0022] Furthermore, existing EPS control algorithms do not distinguish the acceleration control requirements of different driving conditions (normal road conditions, bumpy road conditions, and low-friction road conditions), making it difficult to output appropriate inertial compensation forces, resulting in poor consistency in driving feel (such as sluggish steering at low speeds, light steering at high speeds, heavy driving burden under impact from bad roads, and overly light feel on low-friction surfaces). The above-mentioned solution provided by this invention can at least achieve the following technical effects. 1. This invention standardizes the signals related to the vehicle, sensors, and EPS system through signal processing (slope limiting, filtering, etc.) to provide a reliable data foundation for motor status identification; motor status identification combines multi-dimensional signals such as motor acceleration, rack force, and steering wheel speed to accurately distinguish between normal and abnormal states, and sets hysteresis conditions to avoid repeated state switching; the safety protection strategy classifies fault levels according to the degree of abnormality, executes differentiated power steering reduction or warning strategies, monitors and supports fault switching in real time, thereby quickly responding to motor abnormalities and avoiding safety risks.

[0023] Therefore, this invention can achieve safety protection throughout the entire product lifecycle of EPS, effectively avoid the safety risks caused by abnormal motor vibration, and ensure the safety of drivers and vehicles.

[0024] 2. Based on the acceleration compensation characteristics of different road conditions, this invention identifies three working conditions—normal, bumpy, and low-adhesion—in real time through signals such as rack load, vehicle speed, and hand force. It also sets anti-rebound and hysteresis strategies to avoid frequent switching of working conditions. The acceleration compensation torque calculation is configured with a dedicated gain coefficient for each working condition, and the compensation torque is calculated through the corresponding formula. When switching working conditions, the torque change is limited by gradient to avoid abrupt changes, ensuring that the compensation force adapts to the needs of different working conditions (such as lightness at low speeds and stability at high speeds in normal road conditions, resistance to impact in bumpy road conditions, and increased inertia in low-adhesion road conditions), thereby improving the consistency of driving feel.

[0025] Therefore, this invention can accurately provide acceleration compensation torque for different driving conditions, improve the stability and consistency of driving feel, and reduce driving burden. Attached Figure Description

[0026] The accompanying drawings are intended to illustrate the general characteristics of the methods, structures, and / or materials used in specific exemplary embodiments of the invention, supplementing the description in the specification. However, the drawings are schematic diagrams not drawn to scale and may not accurately reflect the precise structural or performance characteristics of any of the given embodiments. The drawings should not be construed as limiting or restricting the range of numerical values ​​or properties covered by exemplary embodiments of the invention. The invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: Figure 1 This is a control block diagram of the present invention.

[0027] Figure 2 This is a signal processing block diagram of the present invention.

[0028] Figure 3 This is a block diagram of the motor status recognition of the present invention.

[0029] Figure 4 This is a schematic diagram of the working condition identification condition conversion of the present invention.

[0030] Figure 5 This is a schematic diagram of the acceleration compensation gain coefficient under normal road conditions according to the present invention.

[0031] Figure 6 This is a schematic diagram of the acceleration compensation gain coefficient under bumpy road conditions according to the present invention.

[0032] Figure 7 This is a schematic diagram of the acceleration compensation gain coefficient under low-adhesion road conditions according to the present invention. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and various details in this specification can also be applied based on different viewpoints, with various modifications or changes made without departing from the overall design concept of the invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present invention is thorough and complete, and that the technical solutions of these exemplary embodiments are fully conveyed to those skilled in the art. It should be understood that when an element is referred to as "connected" or "combined" to another element, the element can be directly connected or combined to the other element, or there may be intermediate elements. The difference is that when an element is referred to as "directly connected" or "directly combined" to another element, there are no intermediate elements. Throughout the drawings, the same reference numerals always denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] First embodiment; This invention provides an EPS steering acceleration control method, characterized by comprising the following steps: Obtain EPS steering acceleration related parameters from the vehicle's onboard bus; Identify the working status of the steering motor based on EPS steering acceleration-related parameters; If the motor is in an abnormal state, a safety protection strategy will be implemented; if the motor is in a normal state, a feel enhancement strategy will be implemented. The safety protection strategy includes: in abnormal conditions, classifying the abnormal state of the motor into different fault levels according to the number of self-oscillations, with different fault levels corresponding to different assist reduction strategies, and monitoring the abnormal state of the motor in real time and switching faults accordingly. The strategies for improving the feel include: The driving conditions are divided into normal road conditions, bumpy road conditions and low-friction road conditions. The EPS steering acceleration related parameters are monitored in real time to identify the current driving conditions. Calculate the acceleration compensation torque under normal road conditions, bumpy road conditions, and low-adhesion road conditions respectively, and select the corresponding compensation torque according to the currently identified working condition.

[0035] The following describes exemplary feasible embodiments based on the main design concept of the first embodiment described above, taking into account specific vehicle conditions. It should be noted that these feasible embodiments represent what the applicant considers the optimal solution and should not be construed as limitations on the implementation of each step. Correspondingly, the same functions / purposes based on the above main design concept can also be achieved through other existing vehicle technologies, or more complex algorithms or steps, only with slightly inferior technical effects compared to the solution provided by the applicant.

[0036] Based on the above main design ideas, the overall control block diagram is as follows: Figure 1 As shown, the system mainly comprises four functions: signal processing, motor status recognition, safety protection strategy, and handling enhancement strategy. This invention first identifies and determines the motor's operating status in real time by collecting and processing signals from the vehicle and sensors. When an abnormal motor state is detected, a safety protection strategy is implemented to ensure system safety. When the motor state is detected to be normal, a handling enhancement strategy is implemented to optimize steering performance and driving feel.

[0037] Raw signals are acquired through the CAN bus and various sensors, and then processed and operated on (such as filtering, smoothing, limiting, limit checking and validity verification, etc., according to existing signal specifications) to provide reliable input signals for subsequent state recognition and control strategies.

[0038] For example, the vehicle speed signal can be obtained through the CAN bus, and the signal can be checked for limits and validity to ensure that the signal is within a reasonable range and that communication is normal.

[0039] The steering wheel force signal is obtained by a torque sensor, and the signal is checked for limits and validity. Then, it is filtered to eliminate high-frequency noise, and phase adjustment and compensation are performed to correct system delay.

[0040] The steering wheel angle signal is acquired by an angle sensor, and the signal is checked for limits and validity, and then filtered.

[0041] The processed steering wheel angle signal is differentiated to obtain the steering wheel speed signal, and the speed signal is then filtered to smooth out noise.

[0042] The motor rotor speed signal is obtained by the motor position sensor, and the signal is checked for limits and validity, and then filtered.

[0043] The processed motor rotor speed signal is differentiated and smoothed to obtain the motor rotor acceleration signal.

[0044] The rack force signal is obtained by the rack force estimation unit integrated within the EPS system. This signal combines the estimation results of factors such as motor torque, steering wheel force, and system friction.

[0045] The motor status is divided into two types: normal and abnormal. A normal state indicates that the steering motor is working properly without abnormal vibration; an abnormal state indicates that the steering motor is producing unexpected self-vibration or shaking. The identification block diagram is as follows: Figure 3 As shown; For ease of description, the steering wheel angle polarity is specified as left negative and right positive, and the steering wheel rotation direction is clockwise negative and counterclockwise positive (this polarity definition can be flexibly adjusted according to the actual assembly direction of the steering motor or steering gear). Motor status identification requires the following two self-oscillation judgment conditions to be met simultaneously: 1. Rotor acceleration self-vibration judgment: When the positive acceleration of the motor rotor exceeds the set threshold, At that time, at the subsequent set time Inside, the rotor's reverse acceleration also exceeded the set threshold. And at the set time Inside, the rotor's positive acceleration was detected once again to exceed the set threshold. This happened repeatedly more than the set number of times. Then determine the motor's natural vibration condition (rotor acceleration natural vibration condition). True; 2. Load Matching Determination: Simultaneously observe steering wheel speed, rack force, and vehicle speed signals. When the steering wheel speed reaches the set time... Within, exceeding the set threshold Repeated jumps occur that match the rotor acceleration, and the rack force is less than the threshold obtained by looking up the table based on the vehicle speed. Then determine the motor's self-oscillation condition (load matching self-oscillation condition). True; During initialization, the motor is in a normal state by default. This is achieved when both of the above conditions are met simultaneously.

[0046] When this occurs, it is determined that the steering motor has disengaged from control and is causing unexpected vibrations, and the motor status switches from normal to abnormal.

[0047] If the above-mentioned conditions are no longer met when the motor is in an abnormal state, the exit timer will be started. The timer will continue until the set exit time is reached. If the judgment condition is not met during the timing period, the motor state will return from the abnormal state to the normal state. This hysteresis mechanism can prevent frequent state switching near the judgment threshold.

[0048] Explanation of security protection strategies; When the motor status identification determines that the motor has entered an abnormal state, the EPS system immediately executes a safety protection strategy. This strategy classifies the abnormal state of the motor into different fault levels based on the number of motor vibrations, and designs corresponding power assist reduction safety strategies for each level.

[0049] Fault severity classification: When the natural vibration frequency is greater than the set frequency N1 and less than the set frequency N2, the EPS system enters fault level A. When the natural vibration frequency is greater than the set frequency N2 and less than the set frequency N3, the EPS system enters fault level B. When the number of natural vibrations exceeds the set number N3, the EPS system enters fault level C.

[0050] Safety policies corresponding to each fault level: Fault Level A: The EPS system maintains normal power assist output, but a warning is issued via the instrument panel or sound, and this state can be restored to normal mode; Fault Level B: The EPS system reduces the power assist output according to the settings, usually by 10% to 30% of the current power assist output, and this state can be restored to normal mode; Fault level C: The EPS system reduces the power assist output according to the settings, usually by 30% to 70% of the current power assist output, and this state can be restored to normal mode; Normal mode: The EPS system provides normal power output and does not perform power reduction operation.

[0051] As the number of self-oscillations of the motor increases or decreases, the fault level can be dynamically switched between fault level A, fault level B, fault level C and normal mode to achieve flexible safety protection.

[0052] Explanation of strategies to improve feel; When the motor status identification determines that the motor is in a normal state, the EPS system executes the feel enhancement strategy. The feel enhancement strategy includes two parts: operating condition identification and acceleration compensation torque calculation; Based on the acceleration compensation characteristics required under different driving conditions, the system classifies vehicle driving conditions into three types: normal road conditions, bumpy road conditions, and low-friction road conditions. After software initialization, it defaults to the normal road condition. The three road conditions can be conditionally switched based on real-time monitoring signals, and the switching relationships are as follows: Figure 4 As shown. The specific conversion conditions are as follows: Condition 1, Entering bumpy road conditions: Within the set steering wheel angle range During inward steering, the rack load change is monitored in real time; when the rack load reaches a time threshold... The change within exceeds the set threshold. The counter increments by one over a set period of time. If the counter's accumulated value exceeds the set number of times... And during this period, the maximum load on the rack exceeds the set amplitude threshold. If so, it is determined that the road is bumpy; Condition 2, Exit to normal traffic conditions: When within a continuous set time period Inside, the rack load is The change within is less than or equal to If condition 3 (low-adjacent road condition) is not met at the same time, then it is determined that the bumpy road condition is exited and the normal road condition is entered. Condition 3, entering low-adjustment road conditions: Based on the current steering wheel angle, hand force, and motor assist, calculate the theoretical normal rack load under the current operating conditions using a table. And obtain the correction coefficient from the table based on the current vehicle speed. Set the hysteresis interval for low-adjacent road condition judgment. When the actual rack load is monitored Condition 1 must be met: When the timer starts, it will continue until the set entry time is exceeded. If so, it is determined that the road is in a low-adjacent condition; Condition 4, Exiting low-adhesion road conditions: When monitoring rack load Condition 2 is met: When the timer starts, it will continue until the set exit time is exceeded. If the road condition is determined to be low-adjacent, then the road condition will be exited; if condition 1 (bumpy road condition) is not met after exiting, then the road condition will be entered.

[0053] In the entry and exit judgment of bumpy road conditions and low-adhesion road conditions, anti-rebound strategies are implemented using counters and timers, as well as hysteresis intervals. The implemented hysteresis strategy is designed to avoid frequent and abnormal switching of operating conditions.

[0054] Explanation of acceleration compensation torque calculation; The acceleration compensation torque calculation is responsible for calculating the acceleration compensation torque under different working conditions, and selecting the corresponding compensation torque output based on the current working condition identified and sent.

[0055] The calculation of acceleration compensation torque is divided into three operating conditions: Under normal road conditions, the formula for calculating acceleration compensation torque is: ; For acceleration compensation torque under normal road conditions, This is the acceleration compensation gain coefficient under normal road conditions. This is the steering acceleration; The formula for calculating acceleration compensation torque under bumpy road conditions is: ; Torque to compensate for acceleration under bumpy road conditions. This is the acceleration compensation gain coefficient under bumpy road conditions. This is the steering acceleration; The formula for calculating acceleration compensation torque under low-adhesion road conditions is as follows: ; For acceleration compensation torque under low-traction road conditions, This refers to the acceleration compensation gain coefficient under low-adhesion road conditions. This refers to steering acceleration. The acceleration compensation gain coefficients for the three road conditions described above. , and The gain coefficient curve can be obtained by looking up a table based on the current vehicle speed and operating conditions. Different road conditions correspond to different gain coefficient curves, such as... Figure 5 , 6 As shown in Figures 7 and 8.

[0056] Acceleration compensation torque selection: Based on the current operating condition flag sent by the operating condition identification system, the corresponding acceleration compensation torque is selected as the output. Under normal road conditions, the selection... Choose in bumpy road conditions Choose under low-adhesion road conditions .

[0057] When the compensation torque needs to switch from one operating condition to another, the output torque must be limited according to the set gradient. (This value can be specified or calibrated) to ensure a smooth transition and avoid a deterioration in feel caused by sudden torque changes.

[0058] Through the coordinated operation of the above steps, this invention can automatically switch between safety protection mode and feel enhancement mode according to the motor status throughout the entire life cycle of the EPS system; in feel enhancement mode, it can also adaptively adjust the acceleration compensation strategy according to the real-time road conditions, thereby effectively improving the safety, steering performance and driving feel consistency of the electric power steering system.

[0059] Second embodiment; The present invention provides a computer-readable storage medium having a computer program stored therein, which, when executed, is used to implement the steps of the EPS steering acceleration control method described in the first embodiment above.

[0060] The computer-readable medium includes both permanent and non-permanent, removable and non-removable media, which can store information by any method or technology. Information can be computer-readable instructions, data structures, programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include non-transitory computer-readable media, such as modulated data signals and carrier waves.

[0061] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that, unless explicitly defined herein, terms such as those defined in a general dictionary shall be interpreted as having the meaning consistent with their meaning in the relevant field context, and not as having an idealized or overly formal meaning.

[0062] The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. An EPS steering acceleration control method, characterized in that, Includes the following steps: Obtain EPS steering acceleration related parameters from the vehicle's onboard bus; Identify the working status of the steering motor based on EPS steering acceleration-related parameters; If the motor is in an abnormal state, execute the safety protection strategy; If the motor is in normal condition, implement the feel improvement strategy; The safety protection strategy includes: in abnormal conditions, classifying the abnormal state of the motor into different fault levels according to the number of self-oscillations, with different fault levels corresponding to different assist reduction strategies, and monitoring the abnormal state of the motor in real time and switching faults accordingly. The strategies for improving the feel include: Divide driving conditions, monitor EPS steering acceleration parameters in real time, and identify the current driving condition; Calculate the acceleration compensation torque for different driving conditions, and select the corresponding compensation torque based on the currently identified condition.

2. The EPS steering acceleration control method as described in claim 1, characterized in that: Identifying the operating status of the steering motor includes: Initialize the motor status to normal. When the steering wheel speed and motor rotor acceleration repeatedly change beyond a set threshold within a set time range, it is determined that the steering system is vibrating. When vibration occurs, the magnitude and range of the load force on the rack and pinion are used to determine whether the vibration is caused by the motor's self-vibration. If so, it is considered an abnormal state; otherwise, it is considered a normal state.

3. The EPS steering acceleration control method as described in claim 1, characterized in that: In the safety protection strategy, the fault level classification and corresponding assistance reduction strategies are as follows: Fault level A: The number of self-oscillations is greater than the set number N1 and less than the set number N2. The EPS works normally and issues an early warning, and can recover to normal. Fault level B: The number of self-oscillations is greater than the set number N2 and less than the set number N3. The EPS reduces the boost output, but can recover to normal. Fault level C: The number of self-oscillations is greater than the set number N3, the EPS reduces the boost output, and can return to normal. When the number of motor self-oscillations increases or decreases, it can switch between fault levels A, B, C and normal mode; Where N1, N2, and N3 are specified numbers of times.

4. The EPS steering acceleration control method as described in claim 3, characterized in that: Driving conditions are divided into normal road conditions, bumpy road conditions, and low-adhesion road conditions, and the following methods are used to identify driving conditions; Normal road conditions: This is the default setting after initialization. It exits to normal road conditions when the conditions for bumpy road conditions and low-adhesion road conditions are met. Condition 1: Within a specified angle range, if the change in rack load during steering exceeds a set threshold within a specified time threshold, the counter increments by one. If, within a set time, the counter count exceeds the set counting threshold and the maximum rack load exceeds the set threshold, it is determined that the road is in a bumpy condition. Condition 2: If the change in rack load within a specified time threshold is less than or equal to the threshold within a set time period, and condition 3 is not met, then normal road conditions are entered. Condition 3: The normal rack load is calculated by referring to the table based on the angle, hand force and motor assistance. The correction coefficient is obtained by referring to the table based on the vehicle speed. When the rack load meets the conditions of condition 1, the timer starts counting. If the duration exceeds the specified time, it is determined that the vehicle has entered a low-adhesion road condition. Condition 4: When the rack load meets condition 2, the timing starts. If the duration exceeds the specified time, it is determined that the low-adhesion road condition is exited. If condition 1 is not met, it enters the normal road condition.

5. The EPS steering acceleration control method as described in claim 1, characterized in that: The calculation methods for acceleration compensation torque include: Under normal road conditions, acceleration compensation is calculated by multiplying the steering acceleration by the acceleration compensation gain coefficient under normal road conditions. Under bumpy road conditions, acceleration compensation is calculated by multiplying the steering acceleration by the acceleration compensation gain coefficient under bumpy road conditions. Under low-adhesion road conditions, acceleration compensation is calculated by multiplying the steering acceleration by the acceleration compensation gain coefficient under low-adhesion road conditions. The acceleration compensation gain coefficient under different operating conditions can be calculated by looking up a table.

6. The EPS steering acceleration control method according to claim 5, characterized in that: When the compensation torque switches from one operating condition to another, the compensation torque needs to be switched according to the set gradient limit.

7. The EPS steering acceleration control method according to claim 1, characterized in that: EPS steering acceleration related parameters include: vehicle speed, steering wheel torque and angle signal, motor torque, angle, motor speed, motor acceleration signal, steering acceleration signal, and rack force signal.

8. The EPS steering acceleration control method according to claim 7, characterized in that: After validating and filtering the EPS steering acceleration parameters, the steering wheel angle is differentiated and filtered to obtain the steering wheel speed, and the motor speed is differentiated and smoothed to obtain the motor rotor acceleration.

9. The EPS steering acceleration control method according to claim 2, characterized in that: The criteria for determining abnormal motor conditions are as follows: The first direction of the steering wheel is negative, and the second direction is positive; the first direction of the engine speed is negative, and the second direction is positive. When the positive acceleration of the motor rotor exceeds the set threshold, At the set time Inside, the rotor's reverse acceleration also exceeded the set threshold. And at the set time Inside, the rotor's positive acceleration was detected once again to exceed the set threshold. This happened repeatedly more than the set number of times. Then determine the motor's natural vibration condition. True; Simultaneously monitor steering wheel speed, rack force, and vehicle speed. When the steering wheel speed reaches a set time... Within, exceeding the set threshold Repeated jumps occur that match the rotor acceleration, and the rack force is less than the threshold obtained by looking up the table based on the vehicle speed. Then determine the motor's natural vibration condition. True; The default state is normal. The following conditions must be met: ； If the steering motor is found to be disengaged from control and causes unexpected vibration, the motor state changes from normal to abnormal. When the above conditions are no longer met, a timer is started. If the timer exceeds the set time and the above conditions are not met within the timer period, the motor state changes from abnormal to normal.

10. A computer-readable storage medium, characterized in that: It internally stores a computer program, which, when executed, implements the steps of the EPS steering acceleration control method according to any one of claims 1-9.

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