A steer-by-wire road feel control method and system

Abstract

The application relates to a kind of drive-by-wire steering road feel control methods, comprising the following steps: obtaining vehicle state signals, the vehicle state signals at least include vehicle speed signal, steering wheel angle signal, vehicle current total weight signal, steering wheel angle acceleration signal and vertical acceleration signal;Road feel target torque is decoupled into the first channel torque component for representing the basic road feel and load characteristics in vehicle driving and the second channel torque component for representing the disturbance characteristics caused by road roughness.This application realizes the independent control of low-frequency basic road feel and high-frequency road disturbance by decoupling road feel target torque into independent first channel and second channel, and independently modifying two channels based on road roughness index and then summing output, fundamentally solves the contradiction of "enhancing filter road feel loss, weakening filter steering wheel beating" in the related art, and gives consideration to road feel authenticity and driving comfort.

Description

Technical Field

[0001] This invention relates to the field of automotive chassis electronic control technology, specifically to a steer-by-wire road feel control method and system. Background Technology

[0002] With the development of vehicle electrification and intelligence, steer-by-wire systems have gradually become an important development direction for commercial vehicle chassis control. Unlike traditional mechanical or hydraulic steering systems, steer-by-wire systems eliminate the mechanical connection between the steering wheel and the steering wheels. The driver's steering intention is transmitted to the steering actuator through an electrical signal, while the road feedback torque is simulated and transmitted to the steering wheel through a road feel motor to provide the driver with road information and vehicle dynamic information.

[0003] In the existing technology, the road feel control of the steer-by-wire system usually adopts a single-channel torque synthesis method, that is, based on signals such as vehicle speed and steering angle, the basic target torque is obtained by looking up a table through a preset two-dimensional MAP, and then the target torque is linearly scaled according to the load or adhesion coefficient, and finally output to the road feel motor after being smoothed by a low-pass filter. However, the aforementioned technologies, in the process of road feel feedback control, mix tire self-centering force, vehicle load torque, and road impact force into a single target torque output, making it difficult to differentiate based on the physical source of the torque. This easily leads to contradictions: to filter out high-frequency vibrations from unpaved roads, filtering needs to be enhanced, but this also filters out real road texture information, resulting in a loss of road feel; to retain road feel, filtering is weakened, which can cause the steering wheel to "kick back," exacerbating driver fatigue. In addition, most existing technologies only simulate the magnitude of torque, ignoring the differences in rotational inertia under different loads. However, the load difference between unloaded and fully loaded commercial vehicles is huge, with the equivalent rotational inertia difference of the steering system reaching more than 30%. As a result, the steering wheel is prone to being too sensitive and producing a "floaty" feeling when unloaded, and sluggish and producing a "sticky" feeling when heavily loaded. Drivers generally describe this as a lack of realistic steering feel. Therefore, how to effectively suppress high-frequency disturbances while retaining realistic road feel and simulating the real rotational inertia characteristics under different loads is a technical problem that urgently needs to be solved in the field of steer-by-wire road feel control. Summary of the Invention

[0004] This application provides a steer-by-wire road feel control method and system. By decoupling the target torque of the road feel into two independent channels and correcting them separately based on the road surface roughness index, it solves the technical problem in related technologies where single-channel torque synthesis leads to an inability to balance road feel and comfort. At the same time, by introducing virtual inertia compensation that varies nonlinearly with load, it solves the problem of distorted feel caused by ignoring the difference in rotational inertia in related technologies.

[0005] In a first aspect, embodiments of this application provide a steer-by-wire road feel control method, comprising the following steps: Acquire vehicle status signals, which include at least vehicle speed signals, steering wheel angle signals, vehicle current gross weight signals, steering wheel angular acceleration signals, and vertical acceleration signals; The road-feel target torque is decoupled into a first-channel torque component characterizing the basic road feel and load characteristics during vehicle operation, and a second-channel torque component characterizing the disturbance characteristics caused by road surface unevenness. A basic self-centering torque is obtained using the vehicle speed signal and the steering wheel angle signal. A load factor is obtained using the vehicle's current total weight signal. A virtual inertia signal is generated based on the load factor, and the virtual inertia signal increases non-linearly with the load factor. A virtual inertia compensation torque is obtained based on the virtual inertia signal and the steering wheel angular acceleration signal. The basic self-centering torque is scaled by the load factor and then superimposed with the virtual inertia compensation torque to obtain the first-channel torque component. The road surface disturbance torque is obtained through the vertical acceleration signal and used as the second channel torque component; The road surface roughness index is obtained, and the first channel torque component and the second channel torque component are corrected according to the road surface roughness index. The corrected first channel torque component and the second channel torque component are summed to obtain the road feel target torque. The road feel target torque is output to the road feel motor actuator to drive the steering wheel to generate road feel feedback torque.

[0006] In conjunction with the first aspect, in one implementation, the basic self-centering torque is obtained through the vehicle speed signal and the steering wheel angle signal, specifically including: The vehicle speed signal and steering wheel angle signal are used as inputs to generate a basic self-centering torque through a preset mapping relationship.

[0007] In conjunction with the first aspect, in one implementation, obtaining the load factor through the vehicle's current gross weight signal specifically includes: The load factor is calculated by the ratio of the vehicle's current gross weight signal to the calibrated reference vehicle weight.

[0008] In conjunction with the first aspect, in one implementation, a virtual inertia signal is generated based on the load factor, specifically calculated using the following formula: ; in, Based on the value of inertia, Let n be the load factor, where n>1.

[0009] In conjunction with the first aspect, in one implementation, obtaining the virtual inertia compensation torque based on the virtual inertia signal and the steering wheel angular acceleration signal specifically includes: The virtual inertia compensation torque is calculated based on the product of the virtual inertia signal and the steering wheel angular acceleration signal.

[0010] In conjunction with the first aspect, in one implementation, the road surface disturbance torque is obtained through the vertical acceleration signal and used as the second channel torque component, specifically including: The transient vibration component caused by road surface unevenness is extracted from the vertical acceleration signal using a high-pass filter, and the road surface disturbance torque is calculated by combining the tire stiffness parameters.

[0011] In conjunction with the first aspect, in one embodiment, the road surface roughness index is obtained by calculating the standard deviation of the difference values ​​of the left and right height valve sensor signals.

[0012] In conjunction with the first aspect, in one embodiment, the first channel torque component and the second channel torque component are corrected according to the road surface roughness index, specifically including: Obtain the road surface roughness index, and generate a first correction coefficient to characterize the global road feel stability and a second correction coefficient to characterize the degree of adaptive suppression of high-frequency disturbances based on the road surface roughness index; First correction coefficient Calculated using the following formula: ; Second correction coefficient Calculated using the following formula: ; in, The road surface interference suppression coefficient is... For calibration constants, To prevent division by zero of small constants; Multiply the first channel torque component by the first correction coefficient to obtain the corrected first channel torque component; Multiply the second channel torque component by the second correction coefficient to obtain the corrected second channel torque component.

[0013] In conjunction with the first aspect, in one implementation, when acquiring the target torque for road feel, the method further includes: Collect the torque signal input by the driver; The driver's operational behavior characteristics are identified based on the frequency domain characteristics of the driver's input torque signal, and the operational behavior characteristics include at least the frequency and amplitude of the driver's reverse correction direction; The gain coefficient used to characterize the road perception clarity gain is determined based on the aforementioned operational behavior characteristics. ; Based on gain coefficient The second channel torque component is multiplied to further correct the second channel torque component. The road feel target torque is obtained by summing the further corrected second channel torque component with the corrected first channel torque component.

[0014] Secondly, embodiments of this application provide a system for a steer-by-wire road feel control method, comprising: The signal acquisition module is used to acquire vehicle status signals, which include at least vehicle speed signals, steering wheel angle signals, vehicle current total weight signals, steering wheel angular acceleration signals, and vertical acceleration signals. The first channel calculation module is used to obtain the basic self-aligning torque through the vehicle speed signal and the steering wheel angle signal, obtain the load factor through the vehicle's current total weight signal, generate a virtual inertia signal based on the load factor, the virtual inertia signal increases non-linearly with the load factor, obtain a virtual inertia compensation torque based on the virtual inertia signal and the steering wheel angular acceleration signal, and superimpose the basic self-aligning torque with the virtual inertia compensation torque after scaling the load factor to obtain the first channel torque component; The second channel calculation module is used to obtain the road surface disturbance torque through the vertical acceleration signal, which is used as the second channel torque component; The correction fusion module is used to obtain the road surface roughness index, correct the first channel torque component and the second channel torque component according to the road surface roughness index, and sum the corrected first channel torque component and the second channel torque component to obtain the road feel target torque; The execution module is used to output the road-sensing target torque to the road-sensing motor actuator to drive the steering wheel to generate road-sensing feedback torque.

[0015] The beneficial effects of the technical solutions provided in this application include: 1. This application decouples the target torque of road feel into independent first and second channels. The first channel is used to characterize the basic road feel and load characteristics, while the second channel is used to characterize the road surface disturbance characteristics. Based on the road surface roughness index, the two channels are independently corrected and then summed for output. This achieves independent control of low-frequency basic road feel and high-frequency road surface disturbance, enabling the vehicle to independently suppress the high-frequency disturbance component of the second channel on bumpy roads, while fully preserving the low-frequency road feel information of the first channel. This fundamentally solves the contradiction in related technologies where "enhanced filtering leads to loss of road feel, while weakened filtering leads to steering wheel throttle," thus balancing the realism of road feel and driving comfort.

[0016] 2. This application introduces a virtual inertia signal that increases non-linearly with the load factor, and calculates the virtual inertia compensation torque based on the steering wheel angular acceleration. The basic return torque is scaled by the load factor and superimposed with the virtual inertia compensation torque to form the first channel torque component. Compared with related technologies that only simulate the magnitude of torque while ignoring rotational inertia, this application makes the steering wheel generate a resistance proportional to the actual vehicle load when the motion state changes abruptly, such as starting, stopping, and changing direction. It provides a stable "viscous" feel under heavy load and maintains a light but not overly sensitive handling feel under no-load conditions, achieving a realistic physical feel close to that of a mechanical steering system.

[0017] 3. This application is based entirely on the existing sensor signals of the steer-by-wire system—vehicle speed signal, steering wheel angle signal, vehicle current total weight signal, steering wheel angular acceleration signal, and vertical acceleration signal. Through channel decoupling, virtual inertia compensation, and road surface adaptive correction at the algorithm level, it achieves a generational improvement in road feel quality without adding any additional hardware sensors or actuators, and has extremely high engineering feasibility and commercial promotion value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram illustrating the main steps of the present invention; Figure 2 This is a schematic diagram illustrating the calculation of the first channel torque component in this invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] Example 1: Please see Figure 1 This application provides a steer-by-wire road feel control method, which mainly includes the following steps: S1. Obtain vehicle status signal; Vehicle status signals are acquired in real time via the ECU; In this embodiment, the vehicle status signals mainly include: vehicle speed signal. Steering wheel angle signal Vehicle current total weight signal Steering wheel angular acceleration signal and vertical acceleration signal ; Among them, the steering wheel angular acceleration signal It can be obtained from the steering wheel angle sensor signal through differential calculation, or it can be directly collected by a dedicated angular acceleration sensor; Vehicle current gross weight signal It can be estimated by the vehicle control system (VMS) through suspension height valve signals or air suspension pressure sensor signals.

[0022] S2. Calculate the torque component of the first channel; Please see Figure 2 This application decouples the target torque of road feel into a first-channel torque component and a second-channel torque component. The first-channel torque component is used to characterize the basic road feel and load characteristics of the vehicle during driving, and is obtained in the following way: ① Obtain the basic self-centering torque through vehicle speed signal and steering wheel angle signal ; In this embodiment, the vehicle speed signal and steering wheel angle signal are preferably used as inputs, and the basic return torque is generated through a preset mapping relationship; In one specific implementation provided in this embodiment, the preset mapping relationship is a two-dimensional MAP table. The MAP table takes the vehicle speed signal and steering wheel angle signal as input variables and the basic self-centering torque as output variable. The basic self-centering torque value under different vehicle speeds and steering wheel angles is determined through actual vehicle calibration. In a specific example, sample data for a two-dimensional MAP table is shown in Table 1 below:

[0023] Table 1. Two-dimensional MAP table of foundation return torque This data was obtained from actual vehicle calibration. It can be understood that during the calibration process, when the collected vehicle speed signal or steering wheel angle signal does not fall on the discrete grid points of the MAP diagram, the corresponding basic return torque value is calculated by linear interpolation.

[0024] ② Obtain the load factor through the vehicle's current gross weight signal; This embodiment calculates the load factor by the ratio of the vehicle's current total weight signal to the calibrated reference vehicle weight; Specifically, it is calculated using the following formula: ; in, To obtain the vehicle's current total weight signal, The benchmark vehicle weight is determined in advance by calculating the vehicle parameters or by weighing the actual vehicle.

[0025] ③ A virtual inertia signal is generated based on the load factor, and the virtual inertia signal increases non-linearly with the load factor; In this embodiment, a virtual inertia signal is generated based on the load factor, specifically calculated using the following formula: ; in, Based on the value of inertia, Let n be the load factor, and n > 1; This represents the vehicle under the calibrated reference load (i.e. Under the corresponding load conditions, the equivalent moment of inertia of the steering system referred to the steering wheel is predetermined in the following way: During the vehicle calibration phase, the equivalent moment of inertia of the steering wheel and steering column under the calibration load conditions is measured using well-known moment of inertia measurement methods in the art, such as the torsional yaw method or the motor current calibration method; the measured value is then used to determine the equivalent moment of inertia of the steering wheel and steering column under the calibration load conditions. The value is written into the non-volatile memory of the electronic control unit (ECU) as a reference parameter for subsequent virtual inertia calculation.

[0026] In this embodiment, The specific values ​​are determined by actual vehicle calibration based on the steering system parameters of the target vehicle model, for example, the values ​​obtained from the calibration of a heavy commercial vehicle. The value is 0.05 kg·m². Multiply by a coefficient that increases non-linearly with the load factor Then, the virtual inertia under the current load is obtained. ; In addition, in this embodiment, the exponent n is a value greater than 1, preferably n=1.2, to simulate the physical characteristics of the nonlinear increase of inertia with load when a commercial vehicle is under heavy load. Those skilled in the art will understand that in practical applications, the specific value of n can be determined by actual vehicle calibration based on the suspension characteristics, steering system parameters and load distribution of different vehicle models.

[0027] ④ Obtain the virtual inertia compensation torque based on the virtual inertia signal and the steering wheel angular acceleration signal; In this embodiment, the virtual inertia compensation torque is calculated and determined based on the product of the virtual inertia signal and the steering wheel angular acceleration signal, as follows: ; When the vehicle is heavily loaded ( When it is relatively large, Larger, resulting in a larger compensating torque under the same steering wheel angular acceleration. The steering wheel is relatively large, and the driver feels a noticeable "stable" and "sticky" sensation when starting, stopping, or changing direction. When the vehicle is empty ( When it is smaller, Smaller The steering wheel is relatively small and light but not overly sensitive, eliminating the feeling of "floating". When the steering wheel is turned at a constant speed ( When ≈0), ≈0, this compensation torque only works at moments of sudden change in motion state where there is angular acceleration, such as when the steering wheel starts, stops, or changes direction, and does not add additional damping during uniform rotation, which is in line with the motion law of physical rotational systems; Through the aforementioned virtual inertia compensation mechanism, this application enables the steer-by-wire system to simulate a near-realistic physical feel of a mechanical steering system under different load conditions.

[0028] ⑤ The basic aligning torque is scaled by the load factor and then superimposed with the virtual inertia compensation torque to obtain the first channel torque component; The first channel torque component comprises three parts: basic restoring torque. It provides basic road feel for directional stability, enabling the driver to perceive the vehicle's direction of travel and tire lateral slip; load factor The base self-centering torque is scaled to integrate the stability brought by the load into the road feel; the greater the load, the more stable the steering wheel becomes; virtual inertia compensation torque. It provides a damping sensation from physical inertia, so that the steering wheel generates a resistance proportional to the actual load of the vehicle when starting, stopping, and changing direction. These three factors together constitute the basic steering feel that the driver experiences on the steering wheel.

[0029] The first channel torque component is obtained by superimposing the basic restoring torque, scaled by a load factor, with the virtual inertia compensation torque, and is specifically expressed by the following formula: .

[0030] S3. Calculate the torque component of the second channel; The second channel torque component is used to characterize the disturbance characteristics caused by road surface roughness, and is obtained by the following method: [The text abruptly ends here, likely due to an incomplete sentence or missing information.] High-pass filtering is performed to extract the transient vibration components caused by road surface unevenness, and the road disturbance torque is calculated by combining the tire stiffness parameters. As the second channel torque component ; The cutoff frequency of the high-pass filter is determined based on the actual vehicle calibration, and the tire stiffness parameters and steering system force transmission parameters are all preset calibration values. The above-mentioned high-pass filter extraction and torque conversion methods are well-known technologies in the field and will not be described in detail here.

[0031] In the concept of this application, the second channel is specifically designed to carry the high-frequency disturbance component caused by road surface unevenness, and is naturally separated from the low-frequency basic road feel of the first channel in the frequency domain.

[0032] S4. Obtain the road surface roughness index; In this embodiment, the road surface roughness index is obtained by calculating the standard deviation of the difference values ​​between the signals from the left and right height valve sensors. Specifically, the difference between the left and right height valve sensor signals is continuously collected within a preset time period (e.g., 1 second), and the standard deviation of this difference sequence is calculated. The larger the standard deviation, the more bumpy the road surface. In a specific example provided in this embodiment, a flat asphalt road surface... <0.2, gravel road surface >0.8.

[0033] S5. Correct the torque components of the first channel and the second channel; A first correction coefficient is generated based on the pavement roughness index to characterize the overall road feel stability, and a second correction coefficient is generated to characterize the degree of adaptive suppression of high-frequency disturbances. First correction factor Calculated using the following formula: ; Second correction factor Calculated using the following formula: ; in, The road surface interference suppression coefficient is... For calibration constants, To prevent division by zero of small constants; It will be understood by those skilled in the art that and All of these are preset calibration constants, determined in advance through real-vehicle testing during the vehicle's factory calibration phase and stored in the non-volatile memory of the electronic control unit (ECU). During operation, the ECU directly reads and uses these constants. Their specific values ​​are determined through real-vehicle calibration based on the suspension characteristics, steering system parameters, and road feel tuning targets of the target vehicle model. In one specific implementation provided in this embodiment: a typical road surface (such as a flat asphalt road, a rough gravel road, or a jointed road surface) is selected. A steering wheel torque sensor and a steering wheel acceleration sensor are installed on the vehicle to collect road feel feedback data at different vehicle speeds. Subjective evaluation (driver's rating of road feel realism, stability, and comfort) and objective indicators (steering wheel torque fluctuation amplitude, high-frequency vibration attenuation rate, etc.) are used as optimization targets to adjust... and The values ​​are set to ensure clear and realistic road feel feedback on smooth roads and stable and comfortable feedback on bumpy roads. When the various road feel indicators meet the preset thresholds, the current value is recorded. and The value of is written into the electronic control unit.

[0034] In addition, the first correction factor Used to characterize the overall road feel stability when the road surface is bumpy. Reduce the overall output of the first channel to prevent unexpected steering wheel jerking; Second correction factor Used to characterize the degree of adaptive suppression of high-frequency disturbances, when the road surface is bumpy. Rapidly reduce and suppress the gain of the road disturbance channel to avoid excessive high-frequency impact from the road surface being transmitted to the driver's hands; It should be noted that, and exist When the value increases, the value decreases, and The rate of decrease is greater than The rate of decrease is because on bumpy roads, the high-frequency disturbance channel (second channel) should be suppressed first, while the basic road sense channel (first channel) should be appropriately reduced, but not excessively attenuated, otherwise the driver will lose the perception of the vehicle's directional stability. The first channel torque component Multiply by the first correction factor The corrected first-channel torque component is obtained. The second channel torque component Multiply by the second correction factor The corrected second-channel torque component is obtained. ; S6, integrates output road feel target torque.

[0035] The corrected first-channel torque component is summed with the corrected second-channel torque component to obtain the road-feeling target torque, i.e.: +

[0036] The calculated target torque for road feel The output is sent to the road feel motor actuator, and the road feel motor outputs the corresponding feedback torque to the steering wheel according to the torque value, so that the driver can get a realistic and comfortable road feel experience.

[0037] S7, Driver Behavior Adaptation; Based on the above, this application also provides a preferred embodiment, which introduces a gain coefficient to characterize the road feel clarity gain. Specifically: The driver's operating style is identified by collecting the torque signal input from the driver, and the gain coefficient of the second channel torque component is dynamically adjusted accordingly. This enables adaptive adjustment of road feel feedback; Specifically, the ECU also collects the driver's input torque signal (collected by the steering wheel torque sensor), performs frequency domain analysis on the signal, and extracts the driver's operational behavior characteristics. In one specific implementation provided in this embodiment, the number of times the driver makes reverse corrections to the steering wheel per unit time and the magnitude of each correction are counted. When the driver operates smoothly and makes few reverse corrections, the system determines it to be a "smooth driving style" and keeps the gain coefficient β at a high level (e.g., 1.0~1.2) to provide rich road texture information and enhance the driving experience. When a driver frequently makes reverse corrections (e.g., the number of reverse corrections exceeds a preset threshold per unit time), the system determines this to be a sensitive driving style, and in this case, the gain coefficient is reduced. (For example, reducing from the initial value of 1.0 to 0.6~0.8) thereby attenuating the input of road disturbance channels, making the steering wheel "duller", reducing driver tension and arm fatigue. The specific value is determined by real vehicle testing and is used to match the clarity of road feel on different road surfaces.

[0038] Those skilled in the art will understand that the number and magnitude of reverse corrections are only one specific way to determine the driver's operating style. In other embodiments, frequency domain features such as the variance of steering wheel rotation acceleration and the power spectral density distribution of the driver's input torque can also be used to identify the driver's operating style. This application does not limit this.

[0039] During the fusion output stage, the torque component of the second channel is multiplied by this gain coefficient. Then sum it with the torque component of the first channel, that is: + .

[0040] In this embodiment, They work together in the second channel, but with different functions: According to the road surface condition ( This determines "how much road feel the road surface can provide". The driver's behavior determines "how much road feel the driver wants," and the product of these two factors determines the intensity of the road feel disturbance ultimately transmitted to the driver.

[0041] By introducing this gain coefficient This enables personalized road feel matching for drivers, as different drivers have significantly different preferences for road feel intensity. This enables the system to dynamically adjust the road feel intensity based on the driver's own driving behavior characteristics—when the driving is smooth. Maintaining a high value provides rich road surface texture information; frequent reverse corrections are needed. The automatic lowering of the steering wheel makes it "duller," reducing tension and thus shifting the focus from "driver adapting to vehicle" to "vehicle adapting to driver." Simultaneously, it effectively alleviates driving fatigue. On bumpy roads or during long-distance driving, high-frequency road disturbances continuously act on the steering wheel; when the system detects frequent reverse corrections by the driver, it automatically lowers the steering wheel. This reduces road disturbance input, decreases the muscle exertion required by the driver to overcome steering wheel vibration, and effectively alleviates driving fatigue.

[0042] Example 2: This application also provides a system for a steer-by-wire road feel control method, used to execute the steer-by-wire road feel control method in the first embodiment of the above method.

[0043] The system mainly includes a signal acquisition module, a first-channel calculation module, a second-channel calculation module, a correction and fusion module, and an execution module. Specifically: The signal acquisition module is used to acquire vehicle status signals, which include at least vehicle speed, steering wheel angle, current total weight, steering wheel angular acceleration, and vertical acceleration. Specifically, the signal acquisition module is connected to the vehicle speed sensor, steering wheel angle sensor, vehicle control system (VMS), angular acceleration sensor (or differential calculation unit), and vertical acceleration sensor located on the vehicle. It converts the acquired signals into digital signals that can be processed by the electronic control unit and then sends them to the respective calculation modules.

[0044] The first channel calculation module is used to obtain the basic self-centering torque through vehicle speed signal and steering wheel angle signal, obtain the load factor through vehicle current total weight signal, generate a virtual inertia signal based on the load factor, the virtual inertia signal increases non-linearly with the load factor, obtain virtual inertia compensation torque based on virtual inertia signal and steering wheel angular acceleration signal, and superimpose the basic self-centering torque with the virtual inertia compensation torque after scaling by the load factor to obtain the first channel torque component. The specific calculation process of the first channel calculation module has been described in detail in step S2 of embodiment one, and will not be repeated here.

[0045] The second-channel calculation module is used to obtain the road surface disturbance torque through the vertical acceleration signal, which is then used as the second-channel torque component. The second-channel calculation module includes a high-pass filter to extract the transient vibration component caused by road surface unevenness from the vertical acceleration signal, and combines it with a preset tire vertical stiffness coefficient and steering system force transmission parameters to calculate the road surface disturbance torque. The specific calculation process of the second-channel calculation module has been described in detail in step S3 of Embodiment 1, and will not be repeated here.

[0046] The correction and fusion module is used to obtain the road surface roughness index, correct the first channel torque component and the second channel torque component according to the road surface roughness index, and sum the corrected first channel torque component and the second channel torque component to obtain the road feel target torque. The correction and fusion module includes a road surface roughness calculation unit, a correction coefficient generation unit, a multiplication unit and a summation unit. Its specific calculation process has been described in detail in steps S4 to S6 of Embodiment 1, and will not be repeated here.

[0047] The actuator module outputs the target torque from the road feeler to the road feel motor actuator to drive the steering wheel and generate road feel feedback torque. The output of the actuator module is connected to the control terminal of the road feel motor actuator.

[0048] In a preferred embodiment, the system further includes a driver behavior adaptive module, used to acquire the driver's input torque signal, identify the driver's operational behavior characteristics based on the frequency domain characteristics of the driver's input torque signal, and determine the gain coefficient based on the operational behavior characteristics. And multiply the torque component of the second channel by the gain factor. This is to further correct the torque component of the second channel. The specific working process of the driver behavior adaptive module has been described in detail in step S7 of Embodiment 1, and will not be repeated here.

[0049] In this embodiment, the signal transmission relationships between the modules are as follows: the output of the signal acquisition module is connected to the input of the first channel calculation module and the input of the second channel calculation module; the output of the first channel calculation module and the output of the second channel calculation module are connected to the two inputs of the correction fusion module; the output of the correction fusion module is connected to the input of the execution module; in a preferred embodiment with a driver behavior adaptive module, the output of the signal acquisition module is also connected to the input of the driver behavior adaptive module, and the output of the driver behavior adaptive module is connected to the input of the correction fusion module, for inputting the gain coefficient β to the correction fusion module to further correct the torque component of the second channel.

[0050] The system provided in this application embodiment has the same implementation principle and technical effect as the aforementioned method embodiment one. For the sake of brevity, any parts not mentioned in the system embodiment can be referred to the corresponding content in the aforementioned method embodiment one.

[0051] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0052] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A steer-by-wire road feel control method, characterized in that, Includes the following steps: Acquire vehicle status signals, which include at least vehicle speed signals, steering wheel angle signals, vehicle current gross weight signals, steering wheel angular acceleration signals, and vertical acceleration signals; The road-feel target torque is decoupled into a first-channel torque component that characterizes the basic road-feel and load characteristics during vehicle operation and a second-channel torque component that characterizes the disturbance characteristics caused by road surface roughness. The basic self-centering torque is obtained through the vehicle speed signal and the steering wheel angle signal; the load factor is obtained through the vehicle's current total weight signal; a virtual inertia signal is generated based on the load factor, and the virtual inertia signal increases non-linearly with the load factor; a virtual inertia compensation torque is obtained based on the virtual inertia signal and the steering wheel angular acceleration signal. The basic aligning torque is scaled by the load factor and then superimposed with the virtual inertia compensation torque to obtain the torque component of the first channel. The road surface disturbance torque is obtained through the vertical acceleration signal and used as the second channel torque component; The road surface roughness index is obtained, and the first channel torque component and the second channel torque component are corrected according to the road surface roughness index. The corrected first channel torque component and the second channel torque component are summed to obtain the road feel target torque. The road feel target torque is output to the road feel motor actuator to drive the steering wheel to generate road feel feedback torque.

2. The steer-by-wire road feel control method according to claim 1, characterized in that, The basic self-centering torque is obtained by using the vehicle speed signal and the steering wheel angle signal, specifically including: The vehicle speed signal and steering wheel angle signal are used as inputs to generate a basic self-centering torque through a preset mapping relationship.

3. The steer-by-wire road feel control method according to claim 1, characterized in that, The load factor is obtained by using the vehicle's current gross weight signal, specifically including: The load factor is calculated by the ratio of the vehicle's current gross weight signal to the calibrated reference vehicle weight.

4. The steer-by-wire road feel control method according to claim 1, characterized in that, The virtual inertia signal is generated based on the load factor, specifically calculated using the following formula: ； in, Based on the value of inertia, Let n be the load factor, where n>

1.

5. The steer-by-wire road feel control method according to claim 1, characterized in that, The virtual inertia compensation torque is obtained based on the virtual inertia signal and the steering wheel angular acceleration signal, specifically including: The virtual inertia compensation torque is calculated based on the product of the virtual inertia signal and the steering wheel angular acceleration signal.

6. The steer-by-wire road feel control method according to claim 1, characterized in that, The road surface disturbance torque is obtained through the vertical acceleration signal and used as the second channel torque component, specifically including: The transient vibration component caused by road surface unevenness is extracted from the vertical acceleration signal using a high-pass filter, and the road surface disturbance torque is calculated by combining the tire stiffness parameters.

7. The steer-by-wire road feel control method according to claim 1, characterized in that, The road surface roughness index is obtained by calculating the standard deviation of the difference values ​​of the left and right height valve sensor signals.

8. The steer-by-wire road feel control method according to claim 1, characterized in that, The first channel torque component and the second channel torque component are corrected according to the road surface roughness index, specifically including: Obtain the road surface roughness index, and generate a first correction coefficient to characterize the global road feel stability and a second correction coefficient to characterize the degree of adaptive suppression of high-frequency disturbances based on the road surface roughness index; First correction coefficient Calculated using the following formula: ； Second correction coefficient Calculated using the following formula: ； in, The road surface interference suppression coefficient is... For calibration constants, To prevent division by zero of small constants; Multiply the first channel torque component by the first correction coefficient to obtain the corrected first channel torque component; Multiply the second channel torque component by the second correction coefficient to obtain the corrected second channel torque component.

9. The steer-by-wire road feel control method according to claim 1, characterized in that, When obtaining the target torque for road feel, it also includes: Collect the torque signal input by the driver; The driver's operational behavior characteristics are identified based on the frequency domain characteristics of the driver's input torque signal, and the operational behavior characteristics include at least the frequency and amplitude of the driver's reverse correction direction; The gain coefficient used to characterize the road perception clarity gain is determined based on the aforementioned operational behavior characteristics. ; Based on gain coefficient The second channel torque component is multiplied to further correct the second channel torque component. The road feel target torque is obtained by summing the further corrected second channel torque component with the corrected first channel torque component.

10. A system based on the steer-by-wire road feel control method according to claim 1, characterized in that, include: The signal acquisition module is used to acquire vehicle status signals, which include at least vehicle speed signals, steering wheel angle signals, vehicle current total weight signals, steering wheel angular acceleration signals, and vertical acceleration signals. The first channel calculation module is used to obtain the basic self-aligning torque through the vehicle speed signal and the steering wheel angle signal, obtain the load factor through the vehicle's current total weight signal, generate a virtual inertia signal based on the load factor, the virtual inertia signal increases non-linearly with the load factor, obtain a virtual inertia compensation torque based on the virtual inertia signal and the steering wheel angular acceleration signal, and superimpose the basic self-aligning torque with the virtual inertia compensation torque after scaling the load factor to obtain the first channel torque component; The second channel calculation module is used to obtain the road surface disturbance torque through the vertical acceleration signal, which is used as the second channel torque component; The correction fusion module is used to obtain the road surface roughness index, correct the first channel torque component and the second channel torque component according to the road surface roughness index, and sum the corrected first channel torque component and the second channel torque component to obtain the road feel target torque; The execution module is used to output the road-sensing target torque to the road-sensing motor actuator to drive the steering wheel to generate road-sensing feedback torque.

Images