A vehicle steering torque control method and system

Abstract

The present application relates to a kind of vehicle steering torque control method and system, comprising: receiving current requested steering torque X;Obtain the current speed V of vehicle;Identify the current assist mode of vehicle;Wherein the current assist mode at least includes two different modes;According to the current assist mode and the current speed V obtain in current assist mode, corresponding to the current speed of pre-set assist function;According to the current speed V, the steering torque X is corrected to obtain the steering torque X after correction 修正 ;According to the assist function and the steering torque X 修正 Motor execution torque is calculated;According to the motor execution torque control vehicle steering.By the present application, the problem that the steering torque request performance of EPS executing ADAS is inconsistent in the process of lane keeping assistance function control under different steering assist modes can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of driver assistance technology, and more specifically to a vehicle steering torque control method and system. Background Technology

[0002] Most vehicles currently have multiple steering assist modes, meaning they have multiple assist functions, which can be expressed as y = f n (x) represents a pair of input and output relationships, where the input is the input torque of the advanced driver assistance system (ADAS) or the driver, and the output is the torque output of the electric power steering system (EPS) motor. n represents the different assist functions of EPS under different assist modes and different vehicle speeds.

[0003] Currently, ADAS and EPS primarily interact in two ways: torque interface control and angle interface control. When ADAS uses torque interface control, such as... Figure 1 As shown, at the same vehicle speed, simulating the driver's hand force to issue a control signal, the actual EPS receives the steering torque control signal and, by calling the assist function at that speed, converts the hand force torque input by the ADAS into the corresponding motor torque, which is then executed by the EPS's assist motor to drive the steering mechanism and achieve vehicle steering control. The problem with this process is that when the ADAS issues the same steering torque request, the vehicle may be in different steering assist modes at different times. For example, if the driver switches steering assist modes midway through operation, causing the EPS to call different assist functions, the EPS will call different assist functions during the control process. This results in the EPS ultimately executing different assist motor torques for the same ADAS steering torque input. Figure 2 As shown. This issue ultimately leads to the ADAS issuing the same steering torque request at the same vehicle speed under the same operating conditions, simply because the vehicle is in different steering assist modes, the assist motor executes different torque outputs, resulting in different degrees of steering and thus differences in the ADAS's steering control performance of the entire vehicle. Summary of the Invention

[0004] The purpose of this invention is to propose a vehicle steering torque control method and system that can solve the technical problem of inconsistent steering torque request performance of EPS executing ADAS in the lane keeping assist function control process under different steering assist modes.

[0005] To achieve the above objectives, a first embodiment of the present invention provides a vehicle steering torque control method, the method comprising:

[0006] Receive the currently requested steering torque X;

[0007] Get the vehicle's current speed V;

[0008] Identify the vehicle's current power assist mode; wherein the current power assist mode includes at least two different modes;

[0009] Based on the current assist mode and the current vehicle speed V, obtain the pre-set assist function corresponding to the current vehicle speed under the current assist mode;

[0010] The torque correction gain is obtained based on the current power assist mode, the current vehicle speed V, and the steering torque X. The steering torque X is then corrected based on the torque correction gain to obtain the corrected steering torque X. 修正 Alternatively, the corrected steering torque X can be obtained by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ;

[0011] Based on the power assist function and the steering torque X 修正 The motor's operating torque is calculated.

[0012] The motor controls the vehicle's steering by applying torque.

[0013] Preferably, the current assist mode includes at least a first mode and a second mode;

[0014] The process of obtaining torque correction gain based on the current power assist mode, the current vehicle speed V, and the steering torque X includes:

[0015] When the current assist mode is the first mode, the torque correction gain G is obtained by querying pre-stored gain data based on the current vehicle speed and the steering torque X, where the assist mode is the first mode, the vehicle speed is V, and the steering torque is X. 第一模式,v,x When the current assist mode is the second mode, the pre-stored gain data is queried based on the current vehicle speed and the steering torque X, or the torque correction gain G is calculated in real time based on the current vehicle speed and the steering torque X when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x .

[0016] Preferably, the torque correction gain G is calculated in real time based on the current vehicle speed and the steering torque X when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ,include:

[0017] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0018] Obtain the assist function Y = F corresponding to the current vehicle speed V in the second mode. 第二模式,v (X);

[0019] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0020] Based on the steering torque X and the assist function Y = F 第一模式,v (X), the assist function Y = F 第二模式,v (X) and the torque correction gain G 第一模式,v,x Calculate the torque correction gain G 第二模式,v,x ;

[0021] in,

[0022] Preferably, the step of obtaining the corrected steering torque X by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X is described. 修正 ,include:

[0023] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0024] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模 Mode ,v,x ;

[0025] Based on the current vehicle speed V, the steering torque X, and the torque correction gain G 第一模式,v,x And the aforementioned assist function Y = f 第一模式,v (X), calculate the motor execution torque Y when the vehicle speed is V and the steering torque is V in the first mode. 输出 ;

[0026] Based on the steering torque X and the motor execution torque Y 输出 The motor's execution torque Y is obtained by querying the pre-stored assist parameter table. 输出 The execution torque range [Y1,Y2] and the steering torque range [X1,X2] corresponding to the execution torque range [Y1,Y2]; wherein, the power assist parameter table includes multiple steering torques and the motor execution torques of the multiple steering torques in different modes corresponding to multiple different speeds;

[0027] The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 .

[0028] Preferably, the corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2].修正 ,include:

[0029] according to The steering torque X after linear interpolation calculation correction 修正 .

[0030] Preferably, the method further includes:

[0031] The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 Then, based on the steering torque X 修正 Calculate the torque correction gain G 第二模式,v,x And the calculated torque correction gain G 第二模式,v,x It is stored as gain data after being associated with the second mode, speed V, and steering torque X.

[0032] A second embodiment of the present invention provides a vehicle steering torque control system, comprising:

[0033] Torque input unit, used to receive the currently requested steering torque X;

[0034] The vehicle speed acquisition unit is used to acquire the vehicle's current speed V;

[0035] A pattern recognition unit is used to identify the current power assist mode of the vehicle; wherein the current power assist mode includes at least two different modes.

[0036] The assist function acquisition unit is used to obtain a pre-set assist function corresponding to the current vehicle speed in the current assist mode based on the current assist mode and the current vehicle speed V.

[0037] The torque correction unit is used to obtain a torque correction gain based on the current assist mode, the current vehicle speed V, and the steering torque X, and to correct the steering torque X based on the torque correction gain to obtain the corrected steering torque X. 修正 Alternatively, the corrected steering torque X can be obtained by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ;

[0038] The power assist calculation unit is used to calculate the power assist function and the steering torque X. 修正 The motor's operating torque was calculated; and

[0039] A steering control unit is used to control the vehicle steering based on the torque applied by the motor.

[0040] Preferably, the current assist mode includes at least a first mode and a second mode;

[0041] The torque correction unit includes:

[0042] The first correction subunit is used to, when the current assist mode is the first mode, query pre-stored gain data based on the current vehicle speed and the steering torque X to obtain the torque correction gain G when the assist mode is the first mode, the vehicle speed is V, and the steering torque is X. 第一模式,v,x The second correction subunit is used to, when the current assist mode is the second mode, query pre-stored gain data based on the current vehicle speed and the steering torque X, or calculate in real time the torque correction gain G when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ;

[0043] The third correction subunit is used to correct the steering torque X according to the torque correction gain to obtain the corrected steering torque X. 修正 .

[0044] Preferably, the second correction subunit is specifically used for:

[0045] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0046] Obtain the assist function Y = F corresponding to the current vehicle speed V in the second mode. 第二模式,v (X);

[0047] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0048] Based on the steering torque X and the assist function Y = F 第一模式,v (X), the assist function Y = F 第二模式,v (X) and the torque correction gain G 第一模式,v,x Calculate the torque correction gain G 第二模式,v,x ;

[0049] in,

[0050] Preferably, the current assist mode includes at least a first mode and a second mode; the torque correction unit includes a fourth correction subunit;

[0051] The fourth correction subunit is used for:

[0052] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0053] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0054] Based on the current vehicle speed V, the steering torque X, and the torque correction gain G 第一模式,v,x And the aforementioned assist function Y = f 第一模式,v (X), calculate the motor execution torque Y when the vehicle speed is V and the steering torque is V in the first mode. 输出 ;

[0055] Based on the steering torque X and the motor execution torque Y 输出 The motor's execution torque Y is obtained by querying the pre-stored assist parameter table. 输出 The execution torque range [Y1,Y2] and the steering torque range [X1,X2] corresponding to the execution torque range [Y1,Y2]; wherein, the power assist parameter table includes multiple steering torques and the motor execution torques of the multiple steering torques in different modes corresponding to multiple different speeds;

[0056] The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 .

[0057] The above-mentioned vehicle steering torque control method and system have at least the following beneficial effects:

[0058] The above-described method and system, applied to EPS, fully consider the nonlinearity of the power assist function during actual development. By correcting the requested steering torque X based on the current power assist mode and the current vehicle speed V, the method and system can be applied to the calculation of correction parameters for any EPS power assist function / relationship. This ultimately achieves the unification of EPS input and output under different power assist modes, ensuring that ADAS issues the same steering torque request at the same vehicle speed and that the power assist motor executes the same torque output under different power assist modes, resulting in consistent steering. Therefore, it can effectively solve the problem of inconsistent performance of EPS in executing ADAS steering torque requests during lane keeping assist control under different power assist modes. It is suitable for developing lane keeping functions in different modes, reducing performance calibration work, reducing personnel input, and shortening the development cycle. Compared with other correction schemes that treat the power assist function as a linear expression, the various embodiments of the present invention have higher correction accuracy and can maintain higher EPS execution consistency.

[0059] Other features and advantages of the present invention will be set forth in the following description. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a flowchart of the torque interface control method described in the background art.

[0062] Figure 2 This is a schematic diagram illustrating how different steering assist motor torque outputs result from different vehicle speeds and steering torque requests under the same operating conditions, as described in the background art.

[0063] Figure 3 This is a flowchart of a vehicle steering torque control method according to an embodiment of the present invention.

[0064] Figure 4 for Figure 3 The flowchart illustrates the interaction process between ADAS and EPS when the method is applied to EPS.

[0065] Figure 5 for Figure 3 A schematic diagram illustrating the effect of the method shown in the flowchart.

[0066] Figure 6 This is a schematic diagram of a vehicle steering torque control system according to an embodiment of the present invention.

[0067] Figure 7 This is a schematic diagram of a vehicle steering torque control system according to another embodiment of the present invention. Detailed Implementation

[0068] The various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, numerous specific details are set forth in the following detailed embodiments to better illustrate the invention. Those skilled in the art will understand that the invention can be practiced without certain specific details. In some instances, means well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0069] One embodiment of the present invention proposes a vehicle steering torque control method applied to EPS (Electric Power Steering). The EPS executes the steps of the method. In this embodiment, the interaction between ADAS (Advanced Driver Assistance System) and EPS adopts a torque interface control method. Specifically, ADAS sends a requested steering torque X. Upon receiving the steering torque X, EPS simulates the driver's hand force input, causing the steering wheel to generate a corresponding steering torque and steering angle. It then feeds back the current real-time steering torque and steering angle, enabling ADAS to achieve closed-loop control of the steering wheel angle. (See reference...) Figures 3-4 The method in this embodiment includes the following steps:

[0070] Step S1: Receive the currently requested steering torque X;

[0071] Specifically, when the vehicle is in motion, the lane keeping assist function is activated, and the ADAS sends the steering torque X to the EPS through the torque interface;

[0072] Step S2: Obtain the vehicle's current speed V;

[0073] Specifically, the vehicle is equipped with a sensor to detect the vehicle speed. The sensor transmits the real-time detected vehicle speed to the CAN bus for use by various functional units of the vehicle. In this step, the vehicle speed detected by the sensor can be obtained by reading the CAN bus signal, and the current vehicle speed V can be obtained.

[0074] Step S3: Identify the vehicle's current power assist mode; wherein the current power assist mode includes at least two different modes;

[0075] Specifically, vehicles are generally equipped with multiple power assist modes, such as the conventionally defined light mode, baseline mode, and sport mode. In this embodiment, the vehicle power assist modes include at least two, one of which can be used as the baseline mode. Other modes can be extended and set according to different needs. In this embodiment, the parameters of the baseline mode are pre-calibrated, and the parameters of other modes can be obtained based on the baseline mode. For details, please refer to the following content.

[0076] Step S4: Obtain the pre-set assist function corresponding to the current vehicle speed in the current assist mode based on the current assist mode and the current vehicle speed V;

[0077] Specifically, the assist function can be expressed as: Y = F 第i种模式,v (X); where Y is the output motor torque, F 第i种模式,v(X) represents the assist function corresponding to the vehicle speed V when the assist mode is the i-th mode. It is related to the steering torque X requested by ADAS. The parameters of the above functions are all preset according to different assist modes and different vehicle speeds, and are stored in the vehicle's storage device as pre-stored data so that they can be called when the method of this embodiment is implemented.

[0078] It should be noted that in actual development, the assist function may appear to be linear overall or piecewise linear, but in reality, there is no ideal linear performance. Therefore, in this embodiment, based on the known assist functions used in different modes, the gain is further studied and corrected according to the specific actual speed to solve the problem of inconsistent steering torque request performance of EPS executing ADAS.

[0079] Step S5: Obtain torque correction gain based on the current power assist mode, the current vehicle speed V, and the steering torque X, and correct the steering torque X based on the torque correction gain to obtain the corrected steering torque X. 修正 Alternatively, the corrected steering torque X can be obtained by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ;

[0080] Specifically, when correcting the steering torque requested by ADAS, this embodiment considers the current power assist mode and the current vehicle speed. Existing correction methods typically only consider the power assist mode and not the vehicle speed factor. For example, a correction strategy for steering torque under different vehicle speeds in each power assist mode can be determined experimentally and invoked when implementing the method in this embodiment. This embodiment proposes two schemes for correcting the steering torque requested by ADAS. The first is to first calculate the torque correction gain, and then multiply the torque correction gain by the steering torque X to obtain the corrected steering torque X. 修正 The second method is to directly obtain the corrected steering torque X through table lookup and interpolation. 修正 In this embodiment, the first approach can be preferred. If the first approach cannot accurately obtain the torque correction gain, the second approach can be used to obtain the corrected steering torque X. 修正 .

[0081] Step S6: Based on the power assist function and the steering torque X 修正 The motor's operating torque is calculated.

[0082] Specifically, according to the assist function Y=F 第i种模式,v (X) can quickly calculate the motor's operating torque, ultimately achieving the desired result. Figure 5 The effect shown is that, under different modes, the final torque output by the power steering motor is the same at the same vehicle speed with the same steering torque X input.

[0083] Step S7: Control the vehicle steering according to the torque applied by the motor.

[0084] Specifically, the EPS power-assisted motor executes motor torque, at which point the vehicle steers;

[0085] After step S7 is completed, EPS monitors in real time whether ADAS issues a new steering torque X. If so, the above steps are repeated; otherwise, the steering control process ends.

[0086] In some more specific embodiments, the current assist mode includes at least a first mode and a second mode; specifically, the first mode is set as a baseline mode, and the parameters of other assist modes can be obtained based on the first mode.

[0087] In step S5, the torque correction gain is obtained based on the current power assist mode, the current vehicle speed V, and the steering torque X, specifically including:

[0088] Step S51: When the current assist mode is the first mode, query the pre-stored gain data based on the current vehicle speed and the steering torque X to obtain the torque correction gain G when the assist mode is the first mode, the vehicle speed is V, and the steering torque is X. 第一模式,v,x ;

[0089] Specifically, since the first mode is the baseline mode, the torque correction gain of the first mode under different vehicle speeds and different steering torque requests is a preset fixed value; preferably, but not limited to, the torque correction gain of the first mode under different vehicle speeds and different steering torque requests can be set to 1 to facilitate the gain calculation of other modes. In this example, step S51 can be simplified to directly determining its torque correction gain G when the current assist mode is the first mode. 第一模式,v,x When the value is 1, the requested steering torque X is multiplied by the torque correction gain G. 第一模式,v,x It is still equal to the requested steering torque X, therefore, it can also be understood that in the first mode, no torque correction is performed; the above only refers to the torque correction gain G in the first mode. 第一模式,v,x For example, when both are 1, the torque correction gain G in the first mode is shown. 第一模式,v,x It can also be any value other than 1;

[0090] Step S52: When the current assist mode is the second mode, query the pre-stored gain data based on the current vehicle speed and the steering torque X, or calculate the torque correction gain G in real time when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ;

[0091] Specifically, in one example of an embodiment of the present invention, the torque correction gain G corresponding to all vehicle speeds and steering torques in the second mode can be adjusted. 第二模式,v,x After pre-calibration, the data is stored. Subsequently, during vehicle operation, the pre-stored gain data is retrieved to find the corresponding torque correction gain G. 第二模式,v,x This leads to torque correction. While theoretically the gain could be calibrated for all speeds and steering torques, the calibration workload would be enormous. Therefore, this embodiment proposes another example: only the torque correction gain G corresponding to discrete vehicle speeds and steering torques in the second mode is calibrated. 第二模式,v,x Pre-calibration is performed, but for vehicle speeds and steering torques that are not pre-calibrated, the corresponding torque correction gain cannot be directly queried. Instead, it is obtained through real-time calculation to reduce the calibration workload. Furthermore, the real-time calculated torque correction gain can be associated with the mode, vehicle speed, and steering torque and stored in the gain data as a subsequent supplement to the calibration work.

[0092] In some more specific embodiments, step S52 involves calculating the torque correction gain G in real time based on the current vehicle speed and the steering torque X, when the power assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ,include:

[0093] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0094] Obtain the assist function Y = F corresponding to the current vehicle speed V in the second mode. 第二模式,v (X);

[0095] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0096] Based on the steering torque X and the assist function Y = F 第一模式,v (X), the assist function Y = F 第二模式,v (X) and the torque correction gain G 第一模式,v,x Calculate the torque correction gain G 第二模式,v,x ;

[0097] in,

[0098] Specifically, the assist function corresponding to different vehicle speeds in different modes, and the torque correction gain G in the first mode. 第一模式,v,x Since all parameters are known, the torque correction gain G for the second mode can be calculated using the formula above. 第二模式,v,xThe calculated torque correction gain G 第二模式,v,x It is stored as gain data after being associated with the second mode, speed V, and steering torque X.

[0099] According to the above formula, the aforementioned torque correction gain G... 第二模式,v,x The calculation of torque correction gain G is only applicable when the assist function is explicit, continuous, and its inverse function can be directly calculated; however, in some operating conditions, since the assist function cannot be directly obtained and its inverse function cannot be directly expressed, the torque correction gain G is limited. 第二模式,v,x Since it is impossible to calculate, this embodiment proposes the following for this part of the working condition:

[0100] Step S53: Perform lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X to obtain the corrected steering torque X. 修正 Specifically, step S53 includes:

[0101] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0102] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0103] Based on the current vehicle speed V, the steering torque X, and the torque correction gain G 第一模式,v,x And the aforementioned assist function Y = f 第一模式,v (X), calculate the motor execution torque Y when the vehicle speed is V and the steering torque is V in the first mode. 输出 ;

[0104] Based on the steering torque X and the motor execution torque Y 输出 The motor's execution torque Y is obtained by querying the pre-stored assist parameter table. 输出 The execution torque range [Y1,Y2] and the steering torque range [X1,X2] corresponding to the execution torque range [Y1,Y2]; wherein, the power assist parameter table includes multiple steering torques and the motor execution torques of the multiple steering torques in different modes corresponding to multiple different speeds;

[0105] The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 The details are as follows:

[0106] according to The steering torque X after linear interpolation calculation correction 修正 .

[0107] To further clarify, the power assist function depends on the EPS development model and chassis tuning during the vehicle development process. There is no fixed geometric or algebraic relationship, but the following three points can be confirmed:

[0108] (1) If the positive direction of the torque request input and the output torque of the assist motor is defined, then the assist function is a centrally symmetric function. The positive or negative sign of the torque request input value and the motor assist torque output value only indicates the clockwise or counterclockwise direction of the torque. Therefore, the analysis of the torque output problem only needs to focus on the positive torque input and positive torque output.

[0109] (2) In the positive region, the assist function satisfies a monotonically increasing positive correlation, that is, under any mode and vehicle speed, Y increases as X increases; that is, any X value has one and only one corresponding Y; conversely, any Y value also has one and only one corresponding X.

[0110] Therefore, we can use the existing Y=F 第i种模式,v (X) The correction parameters are calculated from the power assist function (determined by the EPS internal model and actual vehicle tuning), and can be combined with... Figure 5 Understanding; according to the purpose of the method in this embodiment, it is necessary to obtain a series of correction parameters G for different assist modes i. 第i种模式,v,x This allows the steering torque X input at the same vehicle speed to result in different final assist motor execution torque Y in different assist modes i, i.e.:

[0111] Y = F 第一模式,v (G 第一模式,v,x *X)=F 第二模式,v (G 第二模式,v,x *X) (1);

[0112] Therefore, by simply providing the functional relationships for different assist modes and vehicle speeds through EPS, selecting the first assist mode, and pre-setting the correction gain for the first assist mode, the correction gain of any mode i relative to the first assist mode can be calculated.

[0113]

[0114] It should be noted that the torque correction for other modes can be obtained by referring to the second mode;

[0115] Among them, G 第一模式,v,x This is the corrected gain expression for the first mode at vehicle speed V and steering torque X. Unless otherwise specified, it can be set to 1 by default, or other values ​​as needed; G 第i种模式,v,x The corrected gain expression for other modes at vehicle speed V and steering torque X is calculated from this formula; F 第一模式,v F is the assist function for the first mode at vehicle speed V; -1第一模式,v It is the inverse function of the assist function in the first mode at vehicle speed V, that is, to find the input value in reverse given the output value;

[0116] Assume Y = F 第i种模式,v (X) all satisfy a direct proportional relationship, that is, Y = k 第i种模式,v *X, and assume the correction gain G in the first assist mode. 第一模式,v All are 1, that is:

[0117] F 第一模式,v (X)=k 第i种模式,v *X, F 第i种模式,v (X)=k 第i种模式,v *X*G 第i种模式,v,x ,

[0118] It can be proven that:

[0119]

[0120] Furthermore, since the objective auxiliary function may not have a readily available expression, or it may be a piecewise function, or even constructed from discrete points, it is not easy to conveniently implement X = F. -1 第一模式,v The inverse transformation operation makes formula (2) very inconvenient in practical use. The embodiment further proposes a method to calculate the correction parameter. For ease of explanation, this is called the "table lookup interpolation method." The following uses two modes—the first mode and the second mode—as examples. In practice, it can be extended to many more modes. The specific implementation steps are as follows:

[0121] Step 1: Obtain the mapping relationship X→Y between the EPS power assist motor torque output and the steering torque request. The form is not limited, and select the first reference mode.

[0122] Step 2: Set discrete vehicle speed values ​​[V1, V2, ..., V] based on actual needs. max1 ] and steering torque input values ​​[X1,X2,…,X max2 The setting methods include, but are not limited to, equal interval setting, equal proportional relationship setting, etc., and the more discrete points selected and the higher the density, the smaller the final calculation error;

[0123] Step 3: Based on the speed and steering torque input values ​​from Step 2, and using the input-output mapping relationship of the two assist modes obtained in Step 1, calculate the corresponding assist motor output torque table / matrix Y. 第一模式 / 2，V1 / V2 / …Vmax1，X1 / X2 / …Xmax2 This is two max1×max2 tables, or rather, a 2×max1×max2 matrix;

[0124] Step 4: Adjust the gain G of the first mode of the base mode.第一模式,V1 / V2 / …Vmax1，X1 / X2 / …Xmax2 All are set to 1 (or can be set to the desired value for other reasons), and the gain G of the second mode is... 第二模式,V1 / V2 / …Vmax1，X1 / X2 / …Xmax2 The quantity to be determined;

[0125] Step 5: To achieve a specific vehicle speed V n In the second mode, X n The input, EPS, produces the same output as in the first assist mode, and directly calculates the vehicle speed V. n In the first mode, X n *G 第一模式,Vn，Xn The corresponding torque output value Y of the boost motor output,Vn,Xn ;(If Y 第一模式，V1 / V2 / …Vmax1，X1 / X2 / …Xmax2 If there is no corresponding value in the table / matrix, Y can be approximated by linear interpolation. output,Vn,Xn ), and at vehicle speed V n Y in the second mode 第二模式，V1 / V2 / …Vmax1，X1 / X2 / …Xmax2 The same booster motor torque output Y is obtained by looking up the table / matrix. output,Vn,Xn The corresponding X 第二模式,Vn,Xn The specific operation method is divided into two sub-steps:

[0126] Step 5-1: Based on the results table from Step 3, determine the value Y. output,Vn,Xn The value of Y in the second mode 第二模式，V1 / V2 / …Vmax1，X1 / X2 / …Xmax2 The Y interval [Y1, Y2] in the table / matrix, and the X interval [X1, X2] corresponding to the [Y1, Y2] interval; where the motor execution torque output Y1 corresponds to the requested steering torque X1, and the motor execution torque output Y2 corresponds to the requested steering torque X2;

[0127] Step 5-2: Obtain X using linear interpolation within the interval [X1, X2]. 第二模式,Vn,Xn (i.e., the above X) adjsut );

[0128]

[0129] Step 6: Calculate the gain G 第二模式,Vn,Xn =X 第二模式,Vn,Xn / X n ;

[0130] Step 7: Repeat steps 5 and 6, selecting different vehicle speed points and input torques to calculate the gain values ​​corresponding to all the vehicle speeds and torques of interest, thus obtaining G. 第二模式,V1 / V2 / … / Vmax1,X1 / X2 / … / Xmax2 ;

[0131] Step 8: If there are other boost modes besides mode0 / 1, such as the i-th mode, repeat steps 1-7 to obtain the gain value G for any mode. 第i种模式,Vn,Xn ;

[0132] Step 9: Finally, after obtaining the discrete gain parameters (n+1×max1×max2 matrix) for all modes through steps 1 to 8, store them as the gain data. In the actual use of the correction parameters, for other working conditions not included in this matrix, you only need to calculate the actual value yourself through interpolation.

[0133] Preferably, the method further includes:

[0134] The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 Then, based on the steering torque X 修正 Calculate the torque correction gain G 第二模式,v,x And the calculated torque correction gain G 第二模式,v,x It is stored as gain data after being associated with the second mode, speed V, and steering torque X.

[0135] Another embodiment of the present invention provides a vehicle steering torque control system, which can be used as a functional system of EPS. It corresponds to the vehicle steering torque control method described in the above embodiments and can be used to execute the various steps of the vehicle steering torque control method described in the above embodiments. Specifically, see [link to relevant documentation]. Figure 6 The system in this embodiment includes the following functional units:

[0136] Torque input unit 1 is used to receive the currently requested steering torque X;

[0137] Vehicle speed acquisition unit 2 is used to acquire the vehicle's current speed V;

[0138] The pattern recognition unit 3 is used to identify the current power assist mode of the vehicle; wherein the current power assist mode includes at least two different modes.

[0139] The assist function acquisition unit 4 is used to obtain a pre-set assist function corresponding to the current vehicle speed in the current assist mode according to the current assist mode and the current vehicle speed V;

[0140] The torque correction unit 5 is used to obtain a torque correction gain based on the current assist mode, the current vehicle speed V, and the steering torque X, and to correct the steering torque X based on the torque correction gain to obtain the corrected steering torque X. 修正 Alternatively, the corrected steering torque X can be obtained by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ;

[0141] The power assist calculation unit 6 is used to calculate the power assist function and the steering torque X. 修正 The motor's operating torque was calculated; and

[0142] Steering control unit 7 is used to control the vehicle steering according to the torque executed by the motor.

[0143] Preferably, the current assist mode includes at least a first mode and a second mode;

[0144] The torque correction unit 5 includes:

[0145] The first correction subunit is used to, when the current assist mode is the first mode, query pre-stored gain data based on the current vehicle speed and the steering torque X to obtain the torque correction gain G when the assist mode is the first mode, the vehicle speed is V, and the steering torque is X. 第一模式,v,x The second correction subunit is used to, when the current assist mode is the second mode, query pre-stored gain data based on the current vehicle speed and the steering torque X, or calculate in real time the torque correction gain G when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ;

[0146] The third correction subunit is used to correct the steering torque X according to the torque correction gain to obtain the corrected steering torque X. 修正 .

[0147] Preferably, the second correction subunit is specifically used for:

[0148] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0149] Obtain the assist function Y = F corresponding to the current vehicle speed V in the second mode. 第二模式,v (X);

[0150] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0151] Based on the steering torque X and the assist function Y = F 第一模式,v (X), the assist function Y = F 第二模式,v (X) and the torque correction gain G 第一模式,v,x Calculate the torque correction gain G 第二模式,v,x ;

[0152] in,

[0153] Preferably, the current assist mode includes at least a first mode and a second mode; the torque correction unit includes a fourth correction subunit;

[0154] The fourth correction subunit is used for:

[0155] Obtain the assist function Y = F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X);

[0156] Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ;

[0157] Based on the current vehicle speed V, the steering torque X, and the torque correction gain G 第一模式,v,x And the aforementioned assist function Y = f 第一模式,v (X), calculate the motor execution torque Y when the vehicle speed is V and the steering torque is V in the first mode. 输出 ;

[0158] Based on the steering torque X and the motor execution torque Y 输出 The motor's execution torque Y is obtained by querying the pre-stored assist parameter table. 输出 The execution torque range [Y1,Y2] and the steering torque range [X1,X2] corresponding to the execution torque range [Y1,Y2]; wherein, the power assist parameter table includes multiple steering torques and the motor execution torques of the multiple steering torques in different modes corresponding to multiple different speeds;

[0159] The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 .

[0160] In some more specific embodiments, see Figure 7 The system also includes:

[0161] Storage unit 8 is used to obtain the corrected steering torque X by linear interpolation of the torque interval [X1,X2] and the torque interval [Y1,Y2] in the fourth correction subunit. 修正 Then, based on the steering torque X 修正 Calculate the torque correction gain G 第二模式,v,x And the calculated torque correction gain G 第二模式,v,x After being associated with the second mode, speed V, and steering torque X, it is stored as gain data; it is also used by the second correction subunit to calculate the torque correction gain G. 第二模式,v,x Then, the calculated torque correction gain G is... 第二模式,v,xIt is stored as gain data after being associated with the second mode, speed V, and steering torque X.

[0162] The systems described in the embodiments above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the system solution in the embodiments, depending on actual needs.

[0163] It should be noted that the system in the above embodiments corresponds to the method in the above embodiments. Therefore, the parts of the system in the above embodiments that are not described in detail can be obtained by referring to the content of the method in the above embodiments. That is, the specific steps recorded in the method in the above embodiments can be understood as the functions that the system in the above embodiments can achieve, and will not be described again here.

[0164] Furthermore, if the system of the above embodiments is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Therefore, as another embodiment, the present invention also proposes a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the vehicle steering torque control method described in the above embodiments.

[0165] As described above, the embodiments of the present invention, applied to EPS, fully consider the nonlinearity of the assist function in real-world development. By correcting the requested steering torque X based on the current assist mode and the current vehicle speed V, the above method and system can be applied to the calculation of correction parameters for any EPS assist function / relationship. This ultimately achieves the unification of EPS input and output under different assist modes, ensuring that ADAS issues the same steering torque request at the same vehicle speed and that the assist motor executes the same torque output under different steering assist modes, resulting in consistent steering. Therefore, it can effectively solve the problem of inconsistent performance of EPS in executing ADAS steering torque requests during lane keeping assist function control under different steering assist modes. It is suitable for developing lane keeping functions in different modes, reducing performance calibration work, reducing personnel input, and shortening the development cycle. Compared with other correction schemes that treat the assist function as a linear expression, the embodiments of the present invention have higher correction accuracy and can maintain higher EPS execution consistency.

[0166] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A vehicle steering torque control method, characterized in that, The method includes: Receive the steering torque X currently requested by the advanced driver assistance system; Get the vehicle's current speed V; Identify the vehicle's current power assist mode; wherein the current power assist mode includes at least two different modes; Based on the current assist mode and the current vehicle speed V, obtain the pre-set assist function corresponding to the current vehicle speed under the current assist mode; The torque correction gain is obtained based on the current power assist mode, the current vehicle speed V, and the steering torque X. The steering torque X is then corrected based on the torque correction gain to obtain the corrected steering torque X. 修正 Alternatively, the corrected steering torque X can be obtained by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ; Based on the power assist function and the steering torque X 修正 The motor's operating torque is calculated. The motor controls the vehicle's steering by applying torque.

2. The vehicle steering torque control method according to claim 1, characterized in that, The current assistance mode includes at least a first mode and a second mode; The process of obtaining torque correction gain based on the current power assist mode, the current vehicle speed V, and the steering torque X includes: When the current assist mode is the first mode, the torque correction gain G is obtained by querying pre-stored gain data based on the current vehicle speed and the steering torque X, where the assist mode is the first mode, the vehicle speed is V, and the steering torque is X. 第一模式,v,x When the current assist mode is the second mode, the pre-stored gain data is queried based on the current vehicle speed and the steering torque X, or the torque correction gain G is calculated in real time based on the current vehicle speed and the steering torque X when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x .

3. The vehicle steering torque control method according to claim 1, characterized in that, The torque correction gain G is calculated in real time based on the current vehicle speed and the steering torque X when the power assist mode is in the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ,include: Obtain the assist function Y=F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X); Obtain the assist function Y=F corresponding to the current vehicle speed V in the second mode. 第二模式,v (X); Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ; Based on the steering torque X and the assist function Y=F 第一模式,v (X), the assist function Y=F 第二模式,v (X) and the torque correction gain G 第一模式,v,x Calculate the torque correction gain G 第二模式,v,x ; in, .

4. The vehicle steering torque control method according to claim 2, characterized in that, The corrected steering torque X is obtained by performing lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ,include: Obtain the assist function Y=F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X); Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ; Based on the current vehicle speed V, the steering torque X, and the torque correction gain G 第一模式,v,x And the aforementioned assist function Y=f 第一模式,v (X), calculates the motor execution torque Y when the vehicle speed is V and the steering torque is V in the first mode. 输出 ; Based on the steering torque X and the motor execution torque Y 输出 The motor's execution torque Y is obtained by querying the pre-stored assist parameter table. 输出 The execution torque range [Y1,Y2] and the steering torque range [X1,X2] corresponding to the execution torque range [Y1,Y2]; wherein, the power assist parameter table includes multiple steering torques and the motor execution torques of the multiple steering torques in different modes corresponding to multiple different speeds; The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 .

5. The vehicle steering torque control method according to claim 4, characterized in that, The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 ,include: according to The steering torque X after linear interpolation calculation correction 修正 .

6. The vehicle steering torque control method according to claim 4, characterized in that, The method further includes: The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 Then, based on the steering torque X 修正 Calculate the torque correction gain G 第二模式,v,x And the calculated torque correction gain G 第二模式,v,x It is stored as gain data after being associated with the second mode, speed V, and steering torque X.

7. A vehicle steering torque control system, characterized in that, include: The torque input unit is used to receive the steering torque X currently requested by the advanced driver assistance system; The vehicle speed acquisition unit is used to acquire the vehicle's current speed V; Pattern recognition unit, used to identify the vehicle's current power assist mode; The current assist mode mentioned above includes at least two different modes; The assist function acquisition unit is used to obtain a pre-set assist function corresponding to the current vehicle speed in the current assist mode based on the current assist mode and the current vehicle speed V. The torque correction unit is used to obtain a torque correction gain based on the current assist mode, the current vehicle speed V, and the steering torque X, and to correct the steering torque X based on the torque correction gain to obtain the corrected steering torque X. 修正 ; Alternatively, the corrected steering torque X can be obtained by lookup table interpolation based on the current power assist mode, the current vehicle speed V, and the steering torque X. 修正 ; The power assist calculation unit is used to calculate the power assist function and the steering torque X. 修正 The motor's operating torque was calculated; and A steering control unit is used to control the vehicle steering based on the torque applied by the motor.

8. The vehicle steering torque control system according to claim 7, characterized in that, The current assistance mode includes at least a first mode and a second mode; The torque correction unit includes: The first correction subunit is used to, when the current assist mode is the first mode, query pre-stored gain data based on the current vehicle speed and the steering torque X to obtain the torque correction gain G when the assist mode is the first mode, the vehicle speed is V, and the steering torque is X. 第一模式,v,x The second correction subunit is used to, when the current assist mode is the second mode, query pre-stored gain data based on the current vehicle speed and the steering torque X, or calculate in real time the torque correction gain G when the assist mode is the second mode, the vehicle speed is V, and the steering torque is X. 第二模式,v,x ; The third correction subunit is used to correct the steering torque X according to the torque correction gain to obtain the corrected steering torque X. 修正 .

9. The vehicle steering torque control system according to claim 8, characterized in that, The second correction subunit is specifically used for: Obtain the assist function Y=F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X); Obtain the assist function Y=F corresponding to the current vehicle speed V in the second mode. 第二模式,v (X); Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ; Based on the steering torque X and the assist function Y=F 第一模式,v (X), the assist function Y=F 第二模式,v (X) and the torque correction gain G 第一模式,v,x Calculate the torque correction gain G 第二模式,v,x ; in, .

10. The vehicle steering torque control system according to claim 7, characterized in that, The current assist mode includes at least a first mode and a second mode; the torque correction unit includes a fourth correction subunit; The fourth correction subunit is used for: Obtain the assist function Y=F corresponding to the current vehicle speed V in the first mode. 第一模式,v (X); Obtain the torque correction gain G when the vehicle speed is V and the steering torque is X in the first mode. 第一模式,v,x ; Based on the current vehicle speed V, the steering torque X, and the torque correction gain G 第一模式,v,x And the aforementioned assist function Y=f 第一模式,v (X), calculate the motor execution torque Y when the vehicle speed is V and the steering torque is V in the first mode. 输出 ; Based on the steering torque X and the motor execution torque Y 输出 The motor's execution torque Y is obtained by querying the pre-stored assist parameter table. 输出 The execution torque range [Y1,Y2] and the steering torque range [X1,X2] corresponding to the execution torque range [Y1,Y2]; wherein, the power assist parameter table includes multiple steering torques and the motor execution torques of the multiple steering torques in different modes corresponding to multiple different speeds; The corrected steering torque X is obtained by linear interpolation based on the torque intervals [X1, X2] and [Y1, Y2]. 修正 .

Images