A method for adaptive compensation of steering wheel output torque and related device

Abstract

The application provides a steering wheel output torque adaptive compensation method and related equipment, obtains the current steering wheel signal and the historical steering wheel signal of the steering wheel of the vehicle, processes the current steering wheel signal and the historical steering wheel signal, obtains the result signal and the input matrix; based on the extended recursive least square method, the input matrix and the result signal are used for parameter fitting, the parameter fitting result is obtained, and the rotational inertia and the friction resistance of the steering wheel are determined according to the parameter fitting result; the vehicle state information of the vehicle is obtained, and the output torque of the steering wheel is determined according to the rotational inertia, the friction resistance and the vehicle state information; the steering wheel is controlled based on the output torque, the parameters depending on the mechanical characteristics of the steering wheel are dynamically adjusted and compensated with the running of the vehicle, the separate development of multiple modules and manual intervention are avoided, and therefore the development cost, the artificial cost, the energy consumption and the calibration time are saved.

Description

Technical Field

[0001] This invention relates to the field of steer-by-wire systems, and more specifically, to an adaptive compensation method and related equipment for steering wheel output torque. Background Technology

[0002] With the development and increasing demand for intelligent vehicles, steer-by-wire systems, as the next generation of steering systems, have emerged. Force feedback steering wheels are a crucial component of steer-by-wire systems. Steer-by-wire systems eliminate the mechanical connection between the steering wheel and the wheels, using two motors to execute steering commands and assist driving, respectively. These motors are connected by a wiring harness, improving both vehicle steering performance and passive safety in the event of an accident. Furthermore, eliminating the mechanical connection between the steering wheel and the wheels frees the vehicle from the constraints of steering mechanism hardware, allowing for a wider range of control strategies for the steering wheel.

[0003] Current steer-by-wire force feedback algorithms primarily consist of a feel feedback module and a torque compensation module. The feel feedback module mainly provides torque feedback commands to the steering wheel based on vehicle conditions; while the torque compensation module primarily compensates for the mechanical parameters of the steering system, such as providing reverse friction compensation torque to eliminate mechanical system friction, ensuring a consistent external experience and improving the vehicle's driving feel while maintaining the uniformity of the feel feedback algorithm across different vehicles. However, in practical applications, to avoid mutual interference between the two modules, it is necessary to separate these two functions into two separate modules and develop them independently.

[0004] In torque compensation modules, various torque compensation functions are often designed to address different characteristics of the mechanical system. These functions include friction compensation, damping compensation, inertia compensation, and compensation for specific needs and operating conditions. However, the primary requirement for torque compensation lies in determining the mechanical characteristics of the vehicle's related systems, such as friction and inertia. The mechanical characteristics of vehicle-related systems are typically determined through manual calibration testing. However, this calibration method is limited by the testing process, requiring individual calibration for each vehicle and failing to guarantee system consistency after changes in mechanical characteristics occur during subsequent vehicle use. Summary of the Invention

[0005] In view of this, the present invention provides an adaptive compensation method and related equipment for steering wheel output torque, so as to avoid separate development between modules and to avoid manual calibration for each vehicle, thereby ensuring the consistency of the system after mechanical characteristics occur during vehicle use.

[0006] The first aspect of this application provides an adaptive compensation method for steering wheel output torque, the method comprising:

[0007] The current steering wheel signal and the historical steering wheel signal of the vehicle are acquired, and the current steering wheel signal and the historical steering wheel signal are processed to obtain the result signal and the input matrix.

[0008] Based on the extended recursive least squares method, the input matrix and the result signal are used to perform parameter fitting to obtain the parameter fitting result, and the rotational inertia and frictional resistance of the steering wheel are determined according to the parameter fitting result.

[0009] The vehicle status information of the vehicle is obtained, and the output torque of the steering wheel is determined based on the moment of inertia, the frictional resistance, and the vehicle status information.

[0010] The steering wheel is controlled based on the output torque.

[0011] Optionally, the step of acquiring the current steering wheel signal and historical steering wheel signal of the vehicle, and processing the current steering wheel signal and the historical steering wheel signal to obtain a result signal and an input matrix includes:

[0012] The vehicle's steering wheel signal and historical steering wheel signal are obtained. The current steering wheel signal includes the current steering wheel angle at the current moment, and the historical steering wheel signal includes the historical steering wheel angle at the previous moment, the historical motor torque acting on the steering wheel at the previous moment, and the historical driver's hand torque.

[0013] The current steering wheel speed is determined based on the current steering wheel angle, and a result signal is generated based on the current steering wheel speed.

[0014] The historical steering wheel speed is determined based on the historical steering wheel angle, and an input matrix is ​​generated based on the historical motor torque, the historical driver's hand torque, and the historical steering wheel speed.

[0015] Optionally, the extended recursive least squares method utilizes the input matrix and the result signal to perform parameter fitting, obtains parameter fitting results, and determines the moment of inertia and frictional resistance of the steering wheel based on the parameter fitting results, including:

[0016] The current steering wheel speed vector in the result signal is used as the output of the extended recursive least squares method, and the historical motor torque vector, historical driver hand torque vector and historical steering wheel speed vector in the input matrix are used as the input of the recursive least squares method and passed into the extended recursive least squares method.

[0017] The extended recursive least squares method is used to fit parameters based on the transmitted input and output to obtain the corresponding parameter fitting results; wherein, the parameter fitting results include at least frictional resistance-related parameters and rotational inertia-related parameters.

[0018] The frictional resistance and rotational inertia of the steering wheel are obtained by performing parameter transformation analysis on the frictional resistance and rotational inertia related parameters.

[0019] Optionally, determining the output torque of the steering wheel based on the moment of inertia, the frictional resistance, and the vehicle state information includes:

[0020] Calculate the feel torque based on the vehicle status information;

[0021] The compensation torque is calculated based on the vehicle status information, the frictional resistance, and the moment of inertia.

[0022] The output torque of the steering wheel is determined by torque arbitration based on the vehicle status information, the feel torque, and the compensation torque.

[0023] Optionally, the step of determining the output torque of the steering wheel by performing torque arbitration based on the vehicle status information, the feel torque, and the compensation torque includes:

[0024] The weighting coefficients of the feel torque and the compensation torque are determined based on the vehicle status information.

[0025] The output torque of the steering wheel is obtained by weighting the feel torque and its weighting coefficient and the compensation torque and its weighting coefficient.

[0026] A second aspect of this application provides an adaptive compensation system for steering wheel output torque, the system comprising:

[0027] The processing module is used to acquire the current steering wheel signal and the historical steering wheel signal of the vehicle's steering wheel, and process the current steering wheel signal and the historical steering wheel signal to obtain the result signal and the input matrix;

[0028] The adaptive parameter fitting module uses the input matrix and the result signal to perform parameter fitting based on the extended recursive least squares method, obtains the parameter fitting result, and determines the rotational inertia and frictional resistance of the steering wheel based on the parameter fitting result.

[0029] The torque compensation module is used to acquire the vehicle status information of the vehicle and determine the output torque of the steering wheel based on the moment of inertia, the frictional resistance and the vehicle status information.

[0030] A control module is used to control the steering wheel based on the output torque.

[0031] Optionally, the processing module is specifically used for:

[0032] The vehicle's steering wheel signal and historical steering wheel signal are obtained. The current steering wheel signal includes the current steering wheel angle at the current moment, and the historical steering wheel signal includes the historical steering wheel angle at the previous moment, the historical motor torque acting on the steering wheel at the previous moment, and the historical driver's hand torque.

[0033] The current steering wheel speed is determined based on the current steering wheel angle, and a result signal is generated based on the current steering wheel speed.

[0034] The historical steering wheel speed is determined based on the historical steering wheel angle, and an input matrix is ​​generated based on the historical motor torque, the historical driver's hand torque, and the historical steering wheel speed.

[0035] A third aspect of this application provides an electronic device, including: a processor and a memory, the processor and the memory being connected via a bus; wherein, the processor is used to call and execute a program stored in the memory; the memory is used to store the program, the program being used to implement the adaptive compensation method for steering wheel output torque as provided in the first aspect of this application.

[0036] A fourth aspect of this application provides a computer-readable storage medium storing computer-executable instructions for performing an adaptive compensation method for steering wheel output torque as provided in the first aspect of this application.

[0037] The fifth aspect of this application provides a vehicle including the electronic device provided in the third aspect of this application, the electronic device being used to perform the adaptive compensation method for steering wheel output torque provided in the first aspect of this application.

[0038] This application provides an adaptive compensation method and related equipment for steering wheel output torque. The method involves acquiring the current and historical steering wheel signals of a vehicle, processing these signals to obtain a result signal and an input matrix, performing parameter fitting using the input matrix and the result signal based on an extended recursive least squares method, obtaining a parameter fitting result, and determining the steering wheel's moment of inertia and frictional resistance based on the parameter fitting result. The method also involves acquiring the vehicle's state information and determining the steering wheel's output torque based on the moment of inertia, frictional resistance, and vehicle state information; and controlling the steering wheel based on the output torque. The technical solution provided in this application first processes the current and historical steering wheel signals into an input matrix and a result signal that satisfy the input and output of the extended recursive least squares method. This allows for online identification using the input matrix and result signal based on the extended recursive least squares method to obtain the corresponding mechanical characteristics (steering wheel moment of inertia and frictional resistance). Finally, based on the obtained mechanical characteristics, corresponding adaptive compensation is performed. This enables the parameters of the steering wheel's mechanical characteristics to be dynamically adjusted and compensated as the vehicle operates, eliminating the need for separate development of multiple modules and manual intervention. This not only saves development costs, labor costs, effort, and calibration time, but also solves the problem in existing technologies where manual calibration testing of the mechanical characteristics of each vehicle fails to guarantee system consistency after changes in mechanical characteristics during subsequent vehicle use. Attached Figure Description

[0039] 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a steer-by-wire system provided in an embodiment of this application;

[0041] Figure 2 This is a flowchart illustrating an adaptive compensation method for steering wheel output torque provided in an embodiment of this application.

[0042] Figure 3 An example diagram of an input signal and identification result provided in an embodiment of this application;

[0043] Figure 4 An example diagram provided for an embodiment of this application shows how to determine the output torque of a steering wheel based on moment of inertia, frictional resistance, and vehicle state information;

[0044] Figure 5 This is a schematic diagram of the structure of an adaptive compensation system for steering wheel output torque provided in an embodiment of this application. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] 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 limitation, 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 the element.

[0047] As can be seen from the background technology above, existing torque compensation modules often design multiple torque compensation functions for different characteristics of mechanical systems. These multiple torque compensation functions include friction compensation, damping compensation, inertia compensation, and compensation for certain special needs and working conditions.

[0048] Specifically, friction compensation is generally divided into two parts: dynamic friction compensation and static friction compensation. Dynamic friction can be considered as a resistance force of fixed magnitude acting in the opposite direction to the steering wheel's rotation. In the actual algorithm, a fixed assist force acting in the same direction as the steering wheel's rotation is designed to compensate for this resistance, with a transition phase from zero to the start of rotation depending on the engine speed. Static friction compensation requires setting a larger static friction value than dynamic friction compensation, and compensating based on the difference between the current hand force and the static friction value, thus ensuring smooth and easy steering wheel rotation from a standstill.

[0049] The main purpose of inertia compensation is to reduce the steering wheel's rotational inertia, preventing the large inertial force during rapid steering wheel rotation from causing difficulty in precise driver control and thus endangering vehicle stability. In practice, it outputs a power assist torque that is related to the steering wheel's rotational inertia, in the same direction as the steering wheel's angular acceleration, and proportional in magnitude, to assist the driver in steering control.

[0050] From the methods of friction compensation and inertia compensation, it can be seen that the main requirement for torque compensation lies in determining the mechanical characteristics of the vehicle's related systems, specifically the mechanical characteristics of the steer-by-wire system and its auxiliary components. For mechanical characteristics such as friction and inertia, the required calibration values ​​are generally determined through manual calibration tests. Specifically, engineers first conduct system identification experiments, import the collected data into a computer for data analysis, and then calibrate the system parameters based on the identification results. However, throughout the vehicle's lifespan, the characteristics and mechanical properties of each subsystem inevitably change over time, necessitating the correction of the calibration parameters within the subsystems.

[0051] However, manual calibration testing is limited by the testing process, requiring individual calibration for each vehicle, and cannot guarantee the consistency of the system after changes in mechanical characteristics during subsequent vehicle use.

[0052] Therefore, this application provides an adaptive compensation method and related equipment for steering wheel output torque. First, the current and historical steering wheel signals are processed into an input matrix and result signal that satisfy the input and output of the extended recursive least squares method. Then, based on the extended recursive least squares method, online identification is performed using the input matrix and result signal to obtain the corresponding mechanical characteristics (steering wheel rotational inertia and frictional resistance). Finally, adaptive compensation is performed based on the obtained mechanical characteristics, thereby enabling the parameters of the steering wheel's mechanical characteristics to be dynamically adjusted and compensated as the vehicle operates. This eliminates the need for developing multiple modules and manual intervention, saving development costs, labor costs, effort, and calibration time. Furthermore, it solves the problem in existing technologies where manual calibration testing of the mechanical characteristics of each vehicle fails to guarantee system consistency after changes in mechanical characteristics during subsequent vehicle use.

[0053] See Figure 1 The illustration shows a steer-by-wire system provided in an embodiment of this application. The steer-by-wire system includes: a road sensor motor 1, a reducer 2, a steering column 3, a torque and angle sensor 4, a steering wheel 5, a steering motor 6, a steering rack 7, and wheels 8.

[0054] The first end of the road sensor motor is connected to the steering wheel via a reducer, steering column, and torque and angle sensors; the second end of the road sensor motor is connected to the steering motor, which is connected to the wheel via a steering rack.

[0055] It should be noted that, from Figure 1 As can be seen from this, the steering wheel and steering rack in the steer-by-wire system provided in this application are not mechanically connected.

[0056] It should also be noted that, in order to further break free from the constraints of steering mechanism hardware, the steering wheel and steering rack in the linear steering system provided in this application are not mechanically connected. However, because the steering wheel and steering rack in the steer-by-wire system are not mechanically connected, it is necessary to independently determine the appropriate basic torque and return torque. In other words, it is necessary to feed back the corresponding torque (the output torque of the steering wheel) to the road sensor motor so that the road sensor motor can output a torque that reflects the current motion of the vehicle and provides a torque to return the steering wheel to center, i.e., output a torque that can control the return of the steering wheel to center, so that the steering wheel returns to center under the action of this torque. Therefore, this application uses an extended recursive least squares method to fit parameters to the result signal and input matrix obtained from the current and historical steering wheel signals. This allows for the subsequent determination of the required moment of inertia and frictional resistance of the steering wheel using the fitted parameters. Finally, based on the vehicle's state information, the steering wheel's moment of inertia, and frictional resistance, the required output torque of the steering wheel is determined. This allows the road sensor motor to output a torque that can return the steering wheel to center, thereby achieving the effect of dynamically adjusting and compensating for parameters dependent on the mechanical characteristics of the steering wheel as the vehicle operates.

[0057] Based on the steer-by-wire system provided in this application, correspondingly, embodiments of this application provide an adaptive compensation method for steering wheel output torque, such as... Figure 2 As shown, this method is adapted to Figure 1 The steer-by-wire system shown in the figure specifically includes the following steps:

[0058] S201: Obtain the current steering wheel signal and historical steering wheel signal of the vehicle, process the current steering wheel signal and historical steering wheel signal to obtain the result signal and input matrix.

[0059] In this embodiment of the application, the study of the steering wheel's motion process (as shown in formula (1)) revealed that different steering wheel speeds, motor torques applied to the steering wheel, and driver hand torques will produce different mechanical characteristics of the steer-by-wire system, such as rotational inertia, damping coefficient, and frictional resistance. Therefore, if one wants to determine the mechanical characteristics of the steer-by-wire system, such as rotational inertia, damping coefficient, and frictional resistance, one can use the motor torque applied to the steering wheel, the driver's hand torque, and the steering wheel speed. The steering wheel's motion process is shown in formula 1.

[0060] (1),

[0061] Where J is the moment of inertia of the steering wheel, B is the damping coefficient of the steering wheel, and f is the frictional resistance of the steering wheel. Steering wheel speed (relative to steering wheel angle) (by taking the derivative) Acceleration of the steering wheel, and These are the motor torque applied to the steering wheel and the driver's hand torque, respectively.

[0062] It should be noted that, It can be obtained from the motor torque value or by calculating it back from the motor current. It can be measured using the torque and torque sensor on the steering wheel.

[0063] It should also be noted that in practical applications, the f value obtained after the steering wheel is turned is the dynamic friction value, which is a constant value with the sign opposite to the direction of rotation; the f value at the moment before the steering wheel starts to turn will obtain the largest f value (greater than the dynamic friction) in the entire estimation process, and the f value at this time will be locked as the static friction value.

[0064] In this application embodiment, it was found that in the prior art, manual calibration testing is limited by the testing process, requiring individual calibration for each vehicle, and cannot guarantee the consistency of the system after changes in mechanical characteristics during subsequent vehicle use. To address this issue, the least squares method can be used to estimate the steering wheel's moment of inertia and frictional resistance. However, the least squares method requires all relevant samples to be obtained before calculation, and the computational resource requirements increase with the sample size, resulting in high computational resource consumption and lacking feasibility for operation on vehicle controllers.

[0065] Therefore, in order to solve the above-mentioned problem, this application uses the recursive least squares method with forgetting factor to identify parameters, that is, the motion process shown in formula (1) is rewritten as the least squares method in the recursive form of separation time, that is, the recursive least squares method with forgetting factor is obtained, as shown in formula (2).

[0066] (2),

[0067] In formula (2), Let k be the steering wheel speed. Let k-1 be the steering wheel speed. The time interval for separation, constant term The coefficient is related to the direction of the steering wheel rotation speed and is used to indicate the direction of frictional resistance. J is the moment of inertia of the steering wheel, B is the damping coefficient of the steering wheel, and f is the frictional resistance of the steering wheel.

[0068] It should be noted that the separation time is also the discrete time, because the actual vehicle controller operates according to discrete time (i.e., fixed time intervals) rather than continuously. Therefore, the separation time here is the actual operating time interval of the vehicle controller.

[0069] In this embodiment, it can be seen from formula (2) that when estimating the moment of inertia and frictional resistance of the steering wheel, in addition to using the steering wheel speed, motor torque, and driver's hand torque at the previous moment, the steering wheel angle at the current moment is also required. Therefore, this application can detect the vehicle's steer-by-wire system in real time to obtain the current steering wheel signal containing the current steering wheel angle at the current moment and the historical steering wheel angle, historical motor torque applied to the steering wheel at the previous moment, and historical driver's hand torque at the previous moment; and process the current steering wheel angle into a result signal that satisfies the output of the extended recursive least squares method, and process the historical steering wheel angle, historical motor torque, and historical driver's hand torque into an input matrix that satisfies the input of the extended recursive least squares method.

[0070] It should be noted that by extending the recursive least squares method, a more accurate steering inertia and frictional resistance of the steering wheel can be fitted using the extended recursive least squares method.

[0071] It should also be noted that the current steering wheel signal and historical steering wheel signal can be obtained through the Torque and Angle Sensor (TAS) and the corresponding controller commands.

[0072] Optionally, the process of acquiring the current steering wheel signal and historical steering wheel signal of the vehicle, and processing the current steering wheel signal and historical steering wheel signal to obtain the result signal and input matrix can be as follows: acquire the current steering wheel signal and historical steering wheel signal of the vehicle, wherein the current steering wheel signal includes the current steering wheel angle at the current moment, and the historical steering wheel signal includes the historical steering wheel angle at the previous moment, the historical motor torque acting on the steering wheel at the previous moment, and the historical driver's hand torque; determine the current steering wheel speed based on the current steering wheel angle, and generate the result signal based on the current steering wheel speed; determine the historical steering wheel speed based on the historical steering wheel angle, and generate the input matrix based on the historical motor torque, the historical driver's hand torque, and the historical steering wheel speed.

[0073] In some embodiments, the current steering wheel signal and historical steering wheel signals of the vehicle's steer-by-wire system at the current moment can be obtained, and after obtaining the current steering wheel signal and historical steering wheel signal, the obtained signals are first filtered and limit-protected.

[0074] In this embodiment of the application, the current steering wheel speed obtained by conversion can be converted into a current steering wheel speed vector to obtain the corresponding result signal; the historical motor torque, historical driver hand torque and historical steering wheel speed can be replaced with historical motor torque vector, historical driver hand torque vector and historical steering wheel speed vector, and the historical motor torque vector, historical driver hand torque vector and historical steering wheel speed vector can be combined to obtain the corresponding input matrix.

[0075] S202: Based on the extended recursive least squares method, the input matrix and the result signal are used to perform parameter fitting to obtain the parameter fitting results, and the rotational inertia and frictional resistance of the steering wheel are determined according to the parameter fitting results.

[0076] In the specific execution step S202, after obtaining the result signal and input matrix, the extended recursive least squares method can be used to perform parameter fitting using the current steering wheel speed vector in the result signal, the historical motor torque vector in the input matrix, the historical driver hand torque vector, and the historical steering wheel speed vector, to obtain the corresponding parameter fitting results. The parameter fitting results include friction resistance related parameters, rotational inertia related parameters, and damping coefficient related parameters. The friction resistance and rotational inertia of the steering wheel are then determined based on the friction resistance related parameters and rotational inertia related parameters.

[0077] Optionally, the process of using the input matrix and result signal to perform parameter fitting based on the extended recursive least squares method to obtain the parameter fitting result, and determining the rotational inertia and frictional resistance of the steering wheel based on the parameter fitting result can be as follows: the current steering wheel speed vector in the result signal is used as the output of the extended recursive least squares method, and the historical motor torque vector, historical driver hand torque vector and historical steering wheel speed vector in the input matrix are used as the input of the extended recursive least squares method; the parameters are fitted according to the transmitted input and output by the extended recursive least squares method to obtain the corresponding parameter fitting result; among which, the parameter fitting result includes at least the frictional resistance related parameters and the rotational inertia related parameters; the frictional resistance related parameters and the rotational inertia related parameters are analyzed by parameter transformation to obtain the frictional resistance and rotational inertia of the steering wheel. Among which, the extended recursive least squares method is shown in formulas (3)-(5).

[0078] (3),

[0079] (4),

[0080] (5),

[0081] In formulas (3)-(5), the subscript k represents the kth sampling time, k-1 represents the (k-1)th sampling time, P is the covariance matrix of the parameter estimation error (a measure of uncertainty), a large value of P means that the uncertainty of the current parameter is high, and it usually decreases gradually as the data increases; K represents the "influence weight" or "learning rate" of the current data on the parameter estimation (parameter fitting result) adjustment, which can also be regarded as the instantaneous correction factor in the recursive least squares (RLS) method. When the value of K is large, it means that the current data has a greater correction effect on the parameter; The parameter estimates obtained from system identification are the parameter fitting results obtained through parameter fitting. Forgetting factor. To eliminate the interference of data that is far removed from the present time on the estimation results, 0.99 is generally taken as the base value; x is the input of the extended recursive least squares method, and y is the output of the extended recursive least squares method.

[0082] It should be noted that, It can include 、( )and ,in, For parameters related to frictional resistance, ( ) Parameters related to moment of inertia and Damping coefficient related parameters. Therefore, it can be seen that at the current moment... After that, it can be used In and By performing parameter transformation analysis, the frictional resistance and moment of inertia of the steering wheel can be obtained.

[0083] It is worth noting that, as can be seen from formulas (3)-(5), in the process of parameter fitting using the extended recursive least squares method, this application only needs to take the current steering wheel speed vector as the output and the historical motor torque vector, historical driver hand torque vector, and historical steering wheel speed vector as the input to complete the corresponding parameter fitting. In other words, after determining the current input and output, the extended recursive least squares method can recursively update the relevant parameters that have been processed before, thereby completing the corresponding parameter fitting. It does not need to obtain all the samples as in the traditional least squares method. This not only greatly reduces computational resources and makes it feasible to run on the vehicle controller, but also eliminates the need for manual intervention, thereby saving labor costs, energy consumption, and calibration time. It also solves the problem in the prior art that the mechanical characteristics of each vehicle are calibrated separately by manual calibration tests, which cannot guarantee the consistency of the system after the mechanical characteristics of the vehicle change during subsequent use.

[0084] In practical applications, when the frictional resistance of the steering wheel is determined to be 1 Nm, an additional 1 Nm needs to be added to the torque output of any actuator as friction compensation. This 1 Nm is the characteristic parameter of friction compensation, and the same applies to the moment of inertia. The input parameters should be used as additional coefficients to compensate based on a well-calibrated algorithm to achieve the best results. For example, in current steer-by-wire systems, the typical friction compensation is set to 0.14 Nm and the moment of inertia compensation to 0.12 kgm². However, after using the adaptive compensation method for the steering wheel output torque provided in this application, the parameters are changed to frictional resistance of 0.135 Nm and moment of inertia of 0.11 kgm². This shows that the parameters are smaller compared to previous offline calibration (i.e., the parameters obtained through the method provided in this application are smaller). Therefore, the technical solution provided in this application can adaptively obtain the corresponding mechanical characteristics (frictional resistance and moment of inertia) as the system changes.

[0085] It is worth noting that the online identification method based on the extended recursive least squares method allows the identification program to run autonomously, eliminating the need for manual intervention and analysis, and saving the effort required for manual calibration. In traditional identification and calibration processes, manual identification experiments are first required, followed by data import into a computer for analysis, and then parameter calibration based on the identification results. However, the online identification method based on the extended recursive least squares method is not only simple to operate but also requires less computing power, allowing it to be directly integrated into the vehicle controller for real-time identification and calibration, significantly reducing calibration time.

[0086] Furthermore, the adaptive compensation method based on online parameter identification (i.e., the adaptive compensation method for steering wheel output torque provided in this application) ensures the operational stability of the steer-by-wire system throughout its entire lifecycle, eliminating the need for factory calibration. During the vehicle's entire lifecycle, the characteristics and mechanical properties of each subsystem inevitably change over time, necessitating the calibration parameters of the subsystems. Traditional calibration methods require professional personnel to operate in a dedicated area, but the method provided in this application can perform real-time calibration while the vehicle is running, or it can select to run a preset response curve for calibration, without requiring professional intervention throughout the entire process, thus ensuring the stability of the system's performance throughout its entire lifecycle.

[0087] In some embodiments, see Figure 3In practical applications, a steering wheel speed signal can be generated based on the real-time steering wheel speed and historical steering wheel speed. The total motor torque can be calculated based on the real-time historical motor torque and historical driver hand torque. The total motor torque signal can be generated based on the real-time total motor torque, so as to generate corresponding input signals based on the steering wheel speed signal and the total motor torque signal. The parameters are fitted using the real-time determined input (input matrix) and output (result signal) according to the extended recursive least squares method, and the obtained moments of inertia and dynamic friction values ​​(friction resistance) are used to generate corresponding identification results.

[0088] S203: Determine the output torque of the steering wheel based on the moment of inertia, frictional resistance, and vehicle status information.

[0089] During the specific execution process S203, after obtaining the rotational inertia and frictional resistance of the steering wheel, the current vehicle state information can be further obtained. In this way, the rotational inertia, frictional resistance, and vehicle state information can be used as inputs to the feedforward correction algorithm of the subsequent torque compensation module. The feedforward correction algorithm can then calculate the output torque of the steering wheel based on the rotational inertia, frictional resistance, and vehicle state information, and then use the obtained output torque to eliminate the adverse effects caused by the differences in the steer-by-wire system itself on the feel feedback.

[0090] Optionally, the process of determining the steering wheel output torque based on rotational inertia, frictional resistance, and vehicle state information can be as follows: See Figure 4 The steering wheel output torque is determined by calculating the feel torque based on the vehicle status information, frictional resistance, and moment of inertia; and by arbitrating the torque based on the vehicle status information, feel torque, and compensation torque.

[0091] In some embodiments, vehicle status information may include parameters such as the vehicle's current speed and wheel angle, and the corresponding feel torque can be calculated based on each parameter in the vehicle status information.

[0092] As one implementation of this application, the process of determining the output torque of the steering wheel by arbitrating torque based on vehicle status information, feel torque, and compensation torque can be as follows: determine the weight coefficients of feel torque and compensation torque respectively based on vehicle status information; and perform weighted calculation based on feel torque and its weight coefficient and compensation torque and its weight coefficient to obtain the output torque of the steering wheel.

[0093] It should be noted that the weighting coefficients of the feel torque and compensation torque can be determined based on parameters such as the current vehicle speed and wheel angle in the vehicle status information.

[0094] In some embodiments, the feedforward correction algorithm of the torque compensation module pre-stores the mapping relationship between mechanical parameters (mechanical characteristics, such as moment of inertia, frictional resistance, etc.) and algorithm calibration values. After calculating the feel torque based on vehicle state information using the feedforward correction algorithm, the algorithm calibration value corresponding to the vehicle state information can be determined according to the mapping relationship, so as to fine-tune the feel torque using the algorithm calibration value. After calculating the compensation torque based on vehicle state information, frictional resistance, and moment of inertia, the algorithm calibration value corresponding to vehicle state information, frictional resistance, and moment of inertia can be determined according to the mapping relationship, so as to fine-tune the compensation torque using the algorithm calibration value. Finally, torque arbitration is performed using vehicle state information, fine-tuned feel torque, and fine-tuned compensation torque to obtain the output torque. The algorithm calibration value corresponding to vehicle state information, fine-tuned feel torque, and fine-tuned compensation torque is determined according to the mapping management, so as to fine-tune the output torque using the algorithm calibration value to obtain the final output torque.

[0095] S204: Steering wheel control based on output torque.

[0096] In the specific execution of step S204, after obtaining the output torque of the steering wheel, the output torque can be sent to the road sensor motor, so that the road sensor motor controls the steering wheel based on the output torque, that is, provides appropriate torque to the steering wheel so that the steering wheel can achieve the effect of returning to center.

[0097] This application provides an adaptive compensation method for steering wheel output torque, applicable to steer-by-wire systems in vehicles. The steer-by-wire system includes at least a road sensor motor, a steering wheel, and a steering rack. The steering wheel and steering rack are not mechanically connected. The method involves acquiring the current and historical steering wheel signals, processing them to obtain a result signal and an input matrix, and then using an extended recursive least squares method to perform parameter fitting with the input matrix and result signal. Based on the parameter fitting result, the method determines the steering wheel's moment of inertia and frictional resistance. The method also acquires vehicle state information and determines the steering wheel's output torque based on the moment of inertia, frictional resistance, and vehicle state information. Finally, the method sends the output torque to the road sensor motor, enabling the road sensor motor to control the steering wheel based on the output torque. The technical solution provided in this application first processes the current and historical steering wheel signals into an input matrix and a result signal that satisfy the input and output of the extended recursive least squares method. This allows for online identification using the input matrix and result signal based on the extended recursive least squares method to obtain the corresponding mechanical characteristics (steering wheel rotational inertia and frictional resistance). Finally, based on the obtained mechanical characteristics, corresponding adaptive compensation is performed to obtain the steering wheel output torque. This eliminates the need for manual intervention, saving labor costs, effort, and calibration time. It also solves the problem in existing technologies where manual calibration testing is used to calibrate the mechanical characteristics of each vehicle individually, which cannot guarantee the consistency of the system after changes in mechanical characteristics during subsequent vehicle use.

[0098] Based on the adaptive compensation method for steering wheel output torque provided in the embodiments of this application above, correspondingly, the embodiments of this application also provide an adaptive compensation system for steering wheel output torque, such as... Figure 5 As shown, the system includes:

[0099] The processing module 51 is used to acquire the current steering wheel signal and the historical steering wheel signal of the vehicle's steering wheel, and process the current steering wheel signal and the historical steering wheel signal to obtain the result signal and the input matrix.

[0100] The adaptive parameter fitting module 52 uses the input matrix and result signal to perform parameter fitting based on the extended recursive least squares method, obtains the parameter fitting result, and determines the rotational inertia and frictional resistance of the steering wheel based on the parameter fitting result.

[0101] The torque compensation module 53 is used to acquire vehicle status information and determine the output torque of the steering wheel based on the moment of inertia, frictional resistance and vehicle status information.

[0102] Control module 54 is used to control the steering wheel based on the output torque.

[0103] This application provides an adaptive compensation system for steering wheel output torque. It acquires the current and historical steering wheel signals of the vehicle's steering wheel, processes these signals to obtain a result signal and an input matrix, and then uses an extended recursive least squares method to perform parameter fitting using the input matrix and the result signal. Based on the parameter fitting result, it determines the steering wheel's moment of inertia and frictional resistance. It also acquires the vehicle's state information and determines the steering wheel's output torque based on the moment of inertia, frictional resistance, and vehicle state information. Finally, it controls the steering wheel based on the output torque. The technical solution provided in this application first processes the current and historical steering wheel signals into an input matrix and result signal that satisfy the input and output of the extended recursive least squares method. This allows for online identification using the input matrix and result signal based on the extended recursive least squares method to obtain the corresponding mechanical characteristics (steering wheel moment of inertia and frictional resistance). Finally, based on the obtained mechanical characteristics, corresponding adaptive compensation is performed to obtain the steering wheel's output torque. This enables the parameters of the steering wheel's mechanical characteristics to be dynamically adjusted and compensated as the vehicle operates, eliminating the need for separate development of multiple modules and manual intervention. This not only saves on labor costs, effort, and calibration time, but also solves the problem in existing technologies where manual calibration testing of the mechanical characteristics of each vehicle fails to guarantee system consistency after changes in mechanical characteristics during subsequent vehicle use.

[0104] Optional, processing module, specifically used for:

[0105] The system acquires the current steering wheel signal and historical steering wheel signal of the vehicle's steering wheel. The current steering wheel signal includes the current steering wheel angle at the current moment, and the historical steering wheel signal includes the historical steering wheel angle at the previous moment, the historical motor torque acting on the steering wheel at the previous moment, and the historical driver's hand torque.

[0106] The current steering wheel speed is determined based on the current steering wheel angle, and a result signal is generated based on the current steering wheel speed.

[0107] The historical steering wheel speed is determined based on the historical steering wheel angle, and an input matrix is ​​generated based on the historical motor torque, historical driver hand torque, and historical steering wheel speed.

[0108] Optional, adaptive parameter fitting module, specifically used for:

[0109] The current steering wheel speed vector in the result signal is used as the output of the extended recursive least squares method, and the historical motor torque vector, historical driver hand torque vector, and historical steering wheel speed vector in the input matrix are used as the input of the extended recursive least squares method.

[0110] The parameters are fitted using the extended recursive least squares method based on the transmitted input and output to obtain the corresponding parameter fitting results; the parameter fitting results include at least the parameters related to frictional resistance and the parameters related to rotational inertia.

[0111] By performing parameter transformation analysis on the parameters related to frictional resistance and rotational inertia, the frictional resistance and rotational inertia of the steering wheel can be obtained.

[0112] Optional torque compensation module, specifically used for:

[0113] Calculate the feel torque based on vehicle status information;

[0114] Calculate the compensation torque based on vehicle status information, frictional resistance, and moment of inertia;

[0115] Based on vehicle status information, feel torque, and compensation torque, torque arbitration is performed to determine the output torque of the steering wheel.

[0116] Optionally, a torque compensation module, which arbitrates torque based on vehicle status information, feel torque, and compensation torque to determine the steering wheel's output torque, is specifically used for:

[0117] The weighting coefficients for the feel torque and the compensation torque are determined based on the vehicle status information.

[0118] The output torque of the steering wheel is obtained by weighting the feel torque and its weighting coefficient and the compensation torque and its weighting coefficient.

[0119] This application also provides a storage medium storing program instructions, which, when loaded and executed by a processor, implement any of the above-described embodiments of the adaptive compensation method for steering wheel output torque.

[0120] This application also provides an electronic device, which includes a processor and a memory, the processor and the memory being connected via a bus; the memory stores program instructions; the processor calls the program instructions in the memory to execute any of the above-described adaptive compensation method embodiments for steering wheel output torque.

[0121] The processor mentioned in this article can be the terminal's CPU, an integrated MCU within the terminal, or a combination of a CPU and an MCU. Furthermore, the processor contains a kernel that retrieves the corresponding program from memory; one or more kernels can be configured.

[0122] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0123] This invention provides a vehicle that includes the electronic device described in the above-described embodiments of this application. The electronic device is used to execute the adaptive compensation method for steering wheel output torque disclosed in the embodiments of this application.

[0124] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described 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 this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0125] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0126] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. 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 the invention. Therefore, the invention 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 disclosed herein.

[0127] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An adaptive compensation method for steering wheel output torque, characterized in that, The method includes: The current steering wheel signal and the historical steering wheel signal of the vehicle are acquired, and the current steering wheel signal and the historical steering wheel signal are processed to obtain the result signal and the input matrix. Based on the extended recursive least squares method, the input matrix and the result signal are used to perform parameter fitting to obtain the parameter fitting result, and the rotational inertia and frictional resistance of the steering wheel are determined according to the parameter fitting result. The vehicle status information of the vehicle is obtained, and the output torque of the steering wheel is determined based on the moment of inertia, the frictional resistance, and the vehicle status information. The steering wheel is controlled based on the output torque.

2. The method according to claim 1, characterized in that, The process of acquiring the current steering wheel signal and historical steering wheel signal of the vehicle, and processing the current steering wheel signal and the historical steering wheel signal to obtain a result signal and an input matrix includes: The vehicle's steering wheel signal and historical steering wheel signal are obtained. The current steering wheel signal includes the current steering wheel angle at the current moment, and the historical steering wheel signal includes the historical steering wheel angle at the previous moment, the historical motor torque acting on the steering wheel at the previous moment, and the historical driver's hand torque. The current steering wheel speed is determined based on the current steering wheel angle, and a result signal is generated based on the current steering wheel speed. The historical steering wheel speed is determined based on the historical steering wheel angle, and an input matrix is ​​generated based on the historical motor torque, the historical driver's hand torque, and the historical steering wheel speed.

3. The method according to claim 1, characterized in that, The extended recursive least squares method uses the input matrix and the result signal to perform parameter fitting, obtains the parameter fitting result, and determines the moment of inertia and frictional resistance of the steering wheel based on the parameter fitting result, including: The current steering wheel speed vector in the result signal is used as the output of the extended recursive least squares method, and the historical motor torque vector, historical driver hand torque vector and historical steering wheel speed vector in the input matrix are used as the input of the recursive least squares method and passed into the extended recursive least squares method. The extended recursive least squares method is used to fit parameters based on the transmitted input and output to obtain the corresponding parameter fitting results; wherein, the parameter fitting results include at least frictional resistance-related parameters and rotational inertia-related parameters. The frictional resistance and rotational inertia of the steering wheel are obtained by performing parameter transformation analysis on the frictional resistance and rotational inertia related parameters.

4. The method according to claim 1, characterized in that, The step of determining the output torque of the steering wheel based on the moment of inertia, the frictional resistance, and the vehicle state information includes: Calculate the feel torque based on the vehicle status information; The compensation torque is calculated based on the vehicle status information, the frictional resistance, and the moment of inertia. The output torque of the steering wheel is determined by torque arbitration based on the vehicle status information, the feel torque, and the compensation torque.

5. The method according to claim 4, characterized in that, The step of determining the output torque of the steering wheel by performing torque arbitration based on the vehicle status information, the feel torque, and the compensation torque includes: The weighting coefficients of the feel torque and the compensation torque are determined based on the vehicle status information. The output torque of the steering wheel is obtained by weighting the feel torque and its weighting coefficient and the compensation torque and its weighting coefficient.

6. An adaptive compensation system for steering wheel output torque, characterized in that, The system includes: The processing module is used to acquire the current steering wheel signal and the historical steering wheel signal of the vehicle's steering wheel, and process the current steering wheel signal and the historical steering wheel signal to obtain the result signal and the input matrix; The adaptive parameter fitting module uses the input matrix and the result signal to perform parameter fitting based on the extended recursive least squares method, obtains the parameter fitting result, and determines the rotational inertia and frictional resistance of the steering wheel based on the parameter fitting result. The torque compensation module is used to acquire the vehicle status information of the vehicle and determine the output torque of the steering wheel based on the moment of inertia, the frictional resistance and the vehicle status information. A control module is used to control the steering wheel based on the output torque.

7. The system according to claim 6, characterized in that, The processing module is specifically used for: The vehicle's steering wheel signal and historical steering wheel signal are obtained. The current steering wheel signal includes the current steering wheel angle at the current moment, and the historical steering wheel signal includes the historical steering wheel angle at the previous moment, the historical motor torque acting on the steering wheel at the previous moment, and the historical driver's hand torque. The current steering wheel speed is determined based on the current steering wheel angle, and a result signal is generated based on the current steering wheel speed. The historical steering wheel speed is determined based on the historical steering wheel angle, and an input matrix is ​​generated based on the historical motor torque, the historical driver's hand torque, and the historical steering wheel speed.

8. An electronic device, characterized in that, include: A processor and a memory are connected via a bus; wherein the processor is used to call and execute a program stored in the memory; The memory is used to store a program for implementing the adaptive compensation method for steering wheel output torque as described in any one of claims 1-5.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for performing the adaptive compensation method for steering wheel output torque as described in any one of claims 1-5.

10. A vehicle, characterized in that, The electronic device of claim 8 is used to perform the adaptive compensation method for steering wheel output torque of any one of claims 1-5.

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