Steer-by-wire system rack force observation method and device

Abstract

The invention relates to a steering-by-wire system rack force observation method and device. The method comprises the steps that vehicle motion information and state information corresponding to a steering-by-wire system are obtained; based on a steering system mechanical model, a first corresponding relation is determined according to the state information, and the first corresponding relation describes the relation between the rack force and the state information; performing yaw angular acceleration analysis processing on the vehicle motion information to obtain yaw angular acceleration data; kinematics analysis processing is conducted on the vehicle motion information and the yaw angle acceleration data, a second corresponding relation is obtained, and the second corresponding relation describes the relation between the rack force change rate and the vehicle motion information and the yaw angle acceleration data; and performing rack force analysis processing based on the first corresponding relation and the second corresponding relation to obtain rack force data. According to the method, calculation of the change rate of the rack force can be introduced in the rack force observation process, the observation delay of the rack force is reduced, and the observation precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wire-controlled steering systems, and in particular to a rack force observation method and device for a wire-controlled steering system. Background Art

[0002] The steer-by-wire system is different from the traditional steering system. There is no direct mechanical structure connecting the steering wheel and the wheels, which means that the force exerted by the ground on the tires during steering cannot be reflected on the steering wheel. Therefore, it is necessary to calculate the rack force to simulate the feel of the steering wheel and thus convey ground information. The rack force observation scheme of the steer-by-wire system in the related art usually requires a priori assumption that the rack force change rate is 0, which is different from the actual situation, resulting in a significant delay in the rack force estimation. Summary of the invention

[0003] In order to solve at least one of the above-mentioned technical problems, the present disclosure proposes a rack force observation method and device for a wire-controlled steering system.

[0004] In one aspect, the present invention provides a rack force observation method for a wire-controlled steering system, comprising:

[0005] Obtain vehicle motion information and state information corresponding to the steer-by-wire system;

[0006] Based on the steering system mechanical model, a first corresponding relationship is determined according to the state information, and the first corresponding relationship describes the relationship between the rack force and the state information;

[0007] Performing yaw angular acceleration analysis on vehicle motion information to obtain yaw angular acceleration data;

[0008] Performing kinematic analysis on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, wherein the second corresponding relationship describes a relationship between a rack force change rate and the vehicle motion information and the yaw angular acceleration data;

[0009] Rack force analysis is performed based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

[0010] In an optional embodiment, kinematic analysis is performed on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, including:

[0011] Based on the vehicle kinematics model, a third corresponding relationship is determined according to the vehicle motion information and the yaw angular acceleration data, wherein the third corresponding relationship describes the relationship between the front axle sideslip angle change rate and the vehicle motion information and the yaw angular acceleration data;

[0012] Based on the tire brush model, a fourth corresponding relationship is determined, and the fourth corresponding relationship describes the relationship between the rate of change of the front axle slip angle and the rate of change of the rack force;

[0013] Based on the third corresponding relationship and the fourth corresponding relationship, a second corresponding relationship is determined.

[0014] In an optional embodiment, rack force analysis is performed based on the first corresponding relationship and the second corresponding relationship to obtain rack force data, including:

[0015] Based on the first corresponding relationship and the second corresponding relationship, a closed-loop observer is constructed;

[0016] The rack force analysis is performed based on the closed-loop observer to obtain the rack force data.

[0017] In an optional embodiment, the vehicle motion information is subjected to yaw angular acceleration analysis to obtain yaw angular acceleration data, including:

[0018] Performing yaw angular acceleration analysis on the front axle side of the vehicle on the vehicle motion information to obtain first initial yaw angular acceleration data;

[0019] Performing yaw angular acceleration analysis on the rear axle side of the vehicle on the vehicle motion information to obtain second initial yaw angular acceleration data;

[0020] An average value of the first initial yaw acceleration data and the second initial yaw acceleration data is determined as the yaw acceleration data.

[0021] In an optional embodiment, the vehicle motion information is subjected to yaw angular acceleration analysis processing on the front axle side of the vehicle to obtain first initial yaw angular acceleration data, including:

[0022] Based on the vehicle dynamics model, a fifth corresponding relationship is determined according to the vehicle motion information, and the fifth corresponding relationship describes the relationship between the front axle lateral force and the yaw angular acceleration;

[0023] Determine the front axle lateral force change rate information;

[0024] Based on the fifth corresponding relationship and the front axle lateral force change rate information, Kalman filter processing is performed to obtain the first initial yaw angular acceleration data.

[0025] In an optional embodiment, the vehicle motion information is subjected to yaw angular acceleration analysis processing on the rear axle side of the vehicle to obtain second initial yaw angular acceleration data, including:

[0026] Based on the vehicle dynamics model, a sixth corresponding relationship is determined according to the vehicle motion information, and the sixth corresponding relationship describes the relationship between the rear axle lateral force and the yaw angular acceleration;

[0027] Determine rear axle lateral force change rate information;

[0028] Based on the sixth corresponding relationship and the rear axle lateral force change rate information, Kalman filtering is performed to obtain second initial yaw angular acceleration data.

[0029] In an optional embodiment, the method further comprises:

[0030] Performing a first-order low-pass filter process based on a first frequency band on the rack force data to obtain a first target rack force;

[0031] Performing a first-order low-pass filtering process based on the second frequency band on the rack force data to obtain a second target rack force, wherein the cutoff frequency corresponding to the second frequency band is less than the cutoff frequency corresponding to the second frequency band, and the second target rack force represents the rack force caused by the driver's operation;

[0032] Subtracting the second target rack force from the first target rack force to obtain a third target rack force, the third target rack force being the rack force caused by the excitation of the rough road surface;

[0033] The rack force data is processed by a second-order bandpass filter based on the third frequency band to obtain a fourth target rack force. The cutoff frequency corresponding to the third frequency band is smaller than the cutoff frequency corresponding to the first frequency band and larger than the cutoff frequency corresponding to the second frequency band. The fourth target rack force represents the rack force caused by the excitation of potholes in the road surface.

[0034] In a second aspect, the present invention further provides a rack force observation device for a wire-controlled steering system, comprising:

[0035] An acquisition module, used to acquire vehicle motion information and state information corresponding to the wire-controlled steering system;

[0036] A first corresponding relationship determination module, used to determine a first corresponding relationship according to the state information based on a steering system mechanical model, the first corresponding relationship describing the relationship between the rack force and the state information;

[0037] The first analysis module is used to perform yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data;

[0038] a second corresponding relationship determination module, configured to perform kinematic analysis on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, wherein the second corresponding relationship describes a relationship between the rack force change rate and the vehicle motion information and the yaw angular acceleration data;

[0039] The second analysis module is used to perform rack force analysis based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

[0040] In a third aspect, the present invention further provides an electronic device, comprising:

[0041] processor;

[0042] a memory for storing processor-executable instructions;

[0043] The processor is used to execute instructions to implement the rack force observation method of the wire-controlled steering system.

[0044] In a fourth aspect, the present invention further provides a storage medium, which, when instructions in the storage medium are executed by a processor of an electronic device, enables the electronic device to execute the above-mentioned rack force observation method of a wire-controlled steering system.

[0045] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0046] The implementation of this disclosure has the following beneficial effects:

[0047] Acquire vehicle motion information and state information corresponding to the wire-controlled steering system; determine a first corresponding relationship based on the state information based on a mechanical model of the steering system, the first corresponding relationship describing the relationship between the rack force and the state information; perform yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data; perform kinematic analysis on the vehicle motion information and yaw angular acceleration data to obtain a second corresponding relationship, the second corresponding relationship describing the relationship between the rack force change rate and the vehicle motion information and yaw angular acceleration data; perform rack force analysis based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

[0048] The present invention determines a first corresponding relationship based on state information based on a steering system mechanical model, and can obtain an expression describing the relationship between the rack force and the state information. By performing kinematic analysis on vehicle motion information and yaw angular acceleration data, the second corresponding relationship is obtained, and an expression describing the relationship between the rack force change rate and the vehicle motion information and yaw angular acceleration data can be obtained. Rack force data is obtained by performing rack force analysis based on the first corresponding relationship and the second corresponding relationship, and the calculation of the rack force change rate can be introduced in the rack force observation process, thereby reducing the observation delay of the rack force and improving the observation accuracy.

[0049] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure, and do not constitute an improper limitation of the present disclosure.

[0051] Figure 1 is a schematic diagram of an implementation environment according to an exemplary embodiment;

[0052] Figure 2 is a flow chart showing a rack force observation method of a wire-controlled steering system according to an exemplary embodiment;

[0053] Figure 3 is a flow chart showing a method of obtaining yaw angular acceleration data according to an exemplary embodiment;

[0054] Figure 4 is a flow chart showing a method of obtaining a second corresponding relationship according to an exemplary embodiment;

[0055] Figure 5 is a flow chart showing a method of obtaining rack force data according to an exemplary embodiment;

[0056] Figure 6 is a flow chart showing a frequency division and filtering process for rack force data according to an exemplary embodiment;

[0057] Figure 7 is a schematic diagram of a rack force observation device for a steer-by-wire system according to an exemplary embodiment;

[0058] Figure 8 The present invention is a block diagram of an electronic device for observing rack force of a steer-by-wire system according to an exemplary embodiment. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0061] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated. The word "exemplary" is used specifically herein to mean "serving as an example, embodiment, or illustrative". Any embodiment described herein as "exemplary" is not necessarily to be construed as being superior or better than other embodiments.

[0062] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0063] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0064] See also Figure 1 , Figure 1 is a schematic diagram of an application environment according to an exemplary embodiment. Figure 1 As shown, the application environment may include a server 01 and a terminal 02 .

[0065] In an optional embodiment, server 01 can be used for calculation and processing of rack force observation method of wire-controlled steering system. Specifically, server 01 can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDN), and big data and artificial intelligence platforms.

[0066] In an optional embodiment, the terminal 02 can perform calculation processing in combination with the rack force observation method of the wire-controlled steering system of the server 01. Specifically, the terminal 02 may include but is not limited to electronic devices such as smart phones, desktop computers, tablet computers, laptops, smart speakers, digital assistants, augmented reality (AR) / virtual reality (VR) devices, smart wearable devices, etc. Optionally, the operating system running on the electronic device may include but is not limited to Android system, IOS system, Linux system, Windows system, Unix system, etc.

[0067] For example, the vehicle motion information and the status information corresponding to the wire-controlled steering system are obtained through the terminal 02 and transmitted to the server 01; the server 01 determines a first corresponding relationship based on the state information based on the mechanical model of the steering system, and the first corresponding relationship describes the relationship between the rack force and the state information; the vehicle motion information is subjected to yaw angular acceleration analysis and processing to obtain yaw angular acceleration data; the vehicle motion information and yaw angular acceleration data are subjected to kinematic analysis and processing to obtain a second corresponding relationship, and the second corresponding relationship describes the relationship between the rate of change of the rack force and the vehicle motion information and the yaw angular acceleration data; the rack force analysis and processing is performed based on the first corresponding relationship and the second corresponding relationship to obtain the rack force data, and the rack force data is transmitted to the terminal 02.

[0068] In addition, it should be noted that Figure 1 What is shown is only one application environment provided by the present disclosure. In actual application, other application environments may also be included.

[0069] In the embodiments of this specification, the server 01 and the terminal 02 may be directly or indirectly connected via wired or wireless communication, which is not limited in this disclosure.

[0070] Figure 2 is a flow chart of a rack force observation method for a wire-controlled steering system according to an exemplary embodiment. Figure 2 As shown, the rack force observation method of the wire steering system includes the following:

[0071] Step S201: Acquire vehicle motion information and state information corresponding to the steer-by-wire system.

[0072] In the embodiment of the present disclosure, the vehicle motion information includes the lateral acceleration a of the center of mass. y , longitudinal speed v x , yaw rate ω, and the corresponding state information of the wire steering system includes the rack position x r , rack speed Rack acceleration The motor outputs torque T. Optionally, the vehicle motion information and the state information corresponding to the steer-by-wire system may be obtained by reading data from a sensor, a gyroscope, or a GPS or by reading data from an electronic control unit of the vehicle through an on-board diagnostic system.

[0073] Step S202: Based on the steering system mechanical model, a first corresponding relationship is determined according to the state information, where the first corresponding relationship describes the relationship between the rack force and the state information.

[0074] In the disclosed embodiment, the steering system mechanical model is a mathematical model used to describe the vehicle steering behavior, which can help understand and predict the dynamic response of the vehicle when turning. Based on the steering system mechanical model, the first corresponding relationship determined according to the state information can be expressed as the following formula (1):

[0075]

[0076] In formula (1), T is the motor output torque, m r is the rack mass, is the rack acceleration, B r is the damping coefficient, is the rack speed, F r is the rack force.

[0077] Step S203: Perform yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data.

[0078] In an optional embodiment, if Figure 3 As shown, the vehicle motion information is analyzed and processed by yaw angular acceleration to obtain yaw angular acceleration data, including:

[0079] Step S2031: analyzing and processing the yaw angular acceleration of the front axle side of the vehicle on the vehicle motion information to obtain first initial yaw angular acceleration data.

[0080] In an optional embodiment, the vehicle motion information is subjected to yaw angular acceleration analysis processing on the front axle side of the vehicle to obtain first initial yaw angular acceleration data, including:

[0081] Based on the vehicle dynamics model, a fifth corresponding relationship is determined according to the vehicle motion information, and the fifth corresponding relationship describes the relationship between the front axle lateral force and the yaw angular acceleration.

[0082] In the disclosed embodiment, the vehicle dynamics model is a two-degree-of-freedom dynamics model of the vehicle, which mainly focuses on the lateral motion and yaw motion of the vehicle. The model can be expressed by the following equations (2) and (3):

[0083] F yf +F yr =ma y (2)

[0084]

[0085] In formula (2) and formula (3), F yf is the lateral force on the front axle, F yr is the lateral force on the rear axle, m is the vehicle weight, a y is the lateral acceleration of the center of mass, l f is the distance from the front axle to the center of mass, l r is the distance from the rear axle to the center of mass, J z is the moment of inertia of the vehicle rotating around the center of mass perpendicular to the horizontal axis, is the yaw angular acceleration.

[0086] In the embodiment of the present disclosure, the rear axle lateral force in the above equations (2) and (3) is eliminated, and the vehicle motion information is substituted, and the determined fifth corresponding relationship can be expressed as the following equation (4):

[0087]

[0088] Determine the front axle lateral force change rate information.

[0089] In the embodiment of the present disclosure, for the convenience of calculation, the front axle lateral force change rate is set to 0, and the obtained front axle lateral force change rate information can be expressed as the following formula (5):

[0090]

[0091] In formula (5), It is the front axle lateral force change rate information.

[0092] Based on the fifth corresponding relationship and the front axle lateral force change rate information, Kalman filter processing is performed to obtain the first initial yaw angular acceleration data.

[0093] In the embodiment of the present disclosure, Kalman filtering is performed based on the fifth corresponding relationship and the front axle lateral force change rate information. The method for obtaining the first initial yaw angular acceleration data can be to define the front axle lateral force and yaw angular acceleration as state quantities, determine equations (4) and (5) as state transfer equation expressions of the state quantities, and then use the yaw angular acceleration as the output to obtain a state space equation, perform Kalman filtering on the state space equation, obtain the value of the yaw angular acceleration, and determine the value of the yaw angular acceleration as the first initial yaw angular acceleration data.

[0094] Based on the above, it can be known that in the embodiment of the present disclosure, by introducing the vehicle dynamics model, the relationship between the front axle lateral force and the yaw angular acceleration can be obtained according to the vehicle dynamics principle, and Kalman filtering processing is performed in combination with the set front axle lateral force change rate information. The first initial yaw angular acceleration data can be obtained by calculating the motion data and dynamic information related to the front axle side of the vehicle.

[0095] Step S2032: analyzing and processing the vehicle motion information on the yaw angular acceleration at the rear axle side of the vehicle to obtain second initial yaw angular acceleration data.

[0096] In an optional embodiment, the vehicle motion information is subjected to yaw angular acceleration analysis processing on the rear axle side of the vehicle to obtain second initial yaw angular acceleration data, including:

[0097] Based on the vehicle dynamics model, a sixth corresponding relationship is determined according to the vehicle motion information, and the sixth corresponding relationship describes the relationship between the rear axle lateral force and the yaw angular acceleration.

[0098] In the embodiment of the present disclosure, the front axle lateral force in the above equations (2) and (3) is eliminated, and the vehicle motion information is substituted, and the determined sixth corresponding relationship can be expressed as the following equation (6):

[0099]

[0100] Determine the rear axle lateral force change rate information.

[0101] In the embodiment of the present disclosure, for the convenience of calculation, the rear axle lateral force change rate is set to 0, and the obtained rear axle lateral force change rate information can be expressed as the following formula (7):

[0102]

[0103] In formula (7), It is the rear axle lateral force change rate information.

[0104] Based on the sixth corresponding relationship and the rear axle lateral force change rate information, Kalman filtering is performed to obtain second initial yaw angular acceleration data.

[0105] In the embodiment of the present disclosure, Kalman filtering is performed based on the sixth corresponding relationship and the rear axle lateral force change rate information. The method for obtaining the second initial yaw angular acceleration data can be to define the rear axle lateral force and yaw angular acceleration as state quantities, determine equations (6) and (7) as state transfer equation expressions of the state quantities, and then use the yaw angular acceleration as the output to obtain a state space equation, perform Kalman filtering on the state space equation, obtain the value of the yaw angular acceleration, and determine the value of the yaw angular acceleration as the second initial yaw angular acceleration data.

[0106] Based on the above, it can be known that in the embodiment of the present disclosure, by introducing the vehicle dynamics model, the relationship between the rear axle lateral force and the yaw angular acceleration can be obtained according to the vehicle dynamics principle, and Kalman filtering processing is performed in combination with the set rear axle lateral force change rate information. The second initial yaw angular acceleration data can be obtained by calculating the motion data and dynamic information related to the rear axle side of the vehicle.

[0107] Step S2033: Determine the average value of the first initial yaw angular acceleration data and the second initial yaw angular acceleration data as the yaw angular acceleration data.

[0108] Based on the above, it can be known that in the embodiment of the present disclosure, the yaw angular acceleration analysis and processing of the vehicle motion information on the front axle side and the rear axle side of the vehicle are respectively performed to obtain two initial yaw angular acceleration data, and the average value is determined as the final yaw angular acceleration data. This can reduce the error in calculating the yaw angular acceleration data corresponding to the front axle side and the rear axle side data respectively, and make the calculated yaw angular acceleration more accurate.

[0109] Step S204: Perform kinematic analysis on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, which describes the relationship between the rack force change rate and the vehicle motion information and the yaw angular acceleration data.

[0110] In an optional embodiment, if Figure 4 As shown, the vehicle motion information and yaw angular acceleration data are subjected to kinematic analysis to obtain a second corresponding relationship, including:

[0111] Step S2041: Based on the vehicle kinematic model, a third corresponding relationship is determined according to the vehicle motion information and the yaw angular acceleration data, and the third corresponding relationship describes the relationship between the front axle sideslip angle change rate and the vehicle motion information and the yaw angular acceleration data.

[0112] In the disclosed embodiment, the vehicle kinematics model mainly focuses on the vehicle's position, speed, acceleration, direction and other motion characteristics. Based on the vehicle kinematics model, the third corresponding relationship determined according to the vehicle motion information and the yaw angular acceleration data can be expressed by the following formula (8):

[0113]

[0114] In formula (8), is the rate of change of the front axle slip angle, is the front wheel steering angle change rate, which is obtained by converting the rack speed and transmission ratio.

[0115] Step S2042: Based on the tire brush model, determine a fourth corresponding relationship, which describes the relationship between the rate of change of the front axle sideslip angle and the rate of change of the rack force.

[0116] In the disclosed embodiment, the tire brush model is used to characterize the calculation relationship between the tire lateral force and the front axle deflection angle, and the fourth corresponding relationship can be obtained by differentiating the tire brush model.

[0117] Step S2043: Determine a second corresponding relationship based on the third corresponding relationship and the fourth corresponding relationship.

[0118] In the embodiment of the present disclosure, the second corresponding relationship can be obtained by substituting the above formula (8) into the derivative result of the tire brush model. The second corresponding relationship is simplified as the following formula (9):

[0119]

[0120] In formula (9), is the rack force change rate, and K represents the calculation performed on the vehicle motion information and yaw angular acceleration data.

[0121] Based on the above, it can be known that in the embodiment of the present disclosure, the relationship between the front axle sideslip angle change rate and the vehicle motion information and yaw angular acceleration data can be obtained through the vehicle kinematic model according to the vehicle kinematic principle. The relationship between the front axle sideslip angle change rate and the rack force change rate can be obtained through the tire brush model according to the tire brush kinematic principle. By deducing the relationship between the above data, the second corresponding relationship can be determined, which facilitates the calculation of the rack force based on the relationship between the rack force change rate and the vehicle motion information and yaw angular acceleration data.

[0122] Step S205: Perform rack force analysis based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

[0123] In an optional embodiment, if Figure 5 As shown, rack force analysis is performed based on the first corresponding relationship and the second corresponding relationship to obtain rack force data, including:

[0124] Step S2051: constructing a closed-loop observer based on the first corresponding relationship and the second corresponding relationship;

[0125] Step S2052: Perform rack force analysis based on the closed-loop observer to obtain rack force data.

[0126] In the embodiment of the present disclosure, the first equation of the observer is the above equation (1), and the second equation of the observer is the above equation (9). Equations (1) and (9) constitute the state transfer equation, and the output is recorded as the rack speed The state space equation is obtained, which is expressed as equation (10).

[0127]

[0128] In formula (10), X is the state vector, u is the motor output torque T, y represents the output, A is the state transfer matrix, B is the control input matrix, w is the process noise matrix, C is the output matrix, and the specific forms of the A, B, C and w matrices are obtained by the process of deducing from equation (1) and equation (9) to equation (10).

[0129] The result of the rack position closed loop is superimposed on the state space equation to correct the error of the observation process and form the final closed loop observer, which is recorded as formula (11).

[0130]

[0131] In formula (11), is the updated vector, L is the closed-loop feedback matrix, is the original value of the rack force given by the observer, the original value of the rack force This is the rack force data.

[0132] Based on the above, it can be known that in the embodiment of the present disclosure, by constructing a closed-loop observer based on the first corresponding relationship and the second corresponding relationship, it is possible to introduce the calculation of the rack force change rate in the rack force observation process, perform rack force analysis and processing based on the closed-loop observer, and obtain rack force data. The closed-loop observer can be used to observe the rack force of the wire-controlled steering system, thereby reducing the observation delay of the rack force and improving the observation accuracy.

[0133] In an optional embodiment, if Figure 6 As shown, the method also includes:

[0134] Step S601: performing a first-order low-pass filtering process based on a first frequency band on the rack force data to obtain a first target rack force.

[0135] In the disclosed embodiment, the cutoff frequency corresponding to the first frequency band is selected as 30 Hz to 40 Hz, and the first target rack force obtained by the first-order low-pass filtering of the rack force data based on the first frequency band combines the rack force caused by the driver's operation and the rack force caused by the excitation of the rough road surface, and the rough road surface includes bad roads such as cobblestone roads and gravel roads.

[0136] Step S602: Perform a first-order low-pass filtering process on the rack force data based on the second frequency band to obtain a second target rack force, wherein the cutoff frequency corresponding to the second frequency band is less than the cutoff frequency corresponding to the second frequency band, and the second target rack force represents the rack force caused by the driver's operation.

[0137] In the disclosed embodiment, the cutoff frequency corresponding to the second frequency band is selected as 10 Hz, and the second target rack force obtained by performing first-order low-pass filtering on the rack force data based on the second frequency band reflects the low-frequency effect. The obtained second target rack force can be used to adjust the driver's feel.

[0138] Step S603: Subtract the second target rack force from the first target rack force to obtain a third target rack force, where the third target rack force is the rack force caused by the excitation of the rough road surface.

[0139] In the disclosed embodiment, the third target rack force obtained by subtracting the second target rack force from the first target rack force reflects stronger mid- and high-frequency effects, and the obtained second target rack force can be used to analyze the influence of excitation on rough roads, such as bad roads like cobblestone roads and gravel roads.

[0140] Step S604: Perform a second-order bandpass filtering process on the rack force data based on the third frequency band to obtain a fourth target rack force. The cutoff frequency corresponding to the third frequency band is less than the cutoff frequency corresponding to the first frequency band and greater than the cutoff frequency corresponding to the second frequency band. The fourth target rack force represents the rack force caused by the excitation of potholes in the road surface.

[0141] In the disclosed embodiment, the rack force data is subjected to a second-order bandpass filtering process with a differential link based on the third frequency band to obtain a fourth target rack force, such as a rack force of 25 Hz to 30 Hz, and when the fourth target rack force exceeds a preset threshold, the obtained fourth target rack force is output, otherwise 0 is output. The fourth target rack force can be used to reflect the influence of occasional lateral excitation, such as potholes that suddenly appear in the road surface.

[0142] Based on the above, it can be known that in the embodiment of the present disclosure, by filtering the rack force data based on different frequency bands, the rack forces caused by different reasons can be obtained respectively, thereby realizing the observation of the rack force caused by the driver's operation, the rack force caused by the excitation of the rough road surface, and the rack force caused by the excitation of the potholes in the road surface.

[0143] Figure 7 FIG. 1 is a block diagram of a rack force observation device for a wire-controlled steering system according to an exemplary embodiment. Figure 7 The device includes an acquisition module 701, a first correspondence determination module 702, a first analysis module 703, a second correspondence determination module 704 and a second analysis module 705, wherein:

[0144] An acquisition module 701 is used to acquire vehicle motion information and state information corresponding to the steer-by-wire system;

[0145] A first correspondence determination module 702, configured to determine a first correspondence according to the state information based on a steering system mechanical model, wherein the first correspondence describes a relationship between the rack force and the state information;

[0146] The first analysis module 703 is used to perform yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data;

[0147] A second corresponding relationship determination module 704 is used to perform kinematic analysis on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, wherein the second corresponding relationship describes the relationship between the rack force change rate and the vehicle motion information and the yaw angular acceleration data;

[0148] The second analysis module 705 is used to perform rack force analysis based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

[0149] In an optional embodiment, the second correspondence determination module 704 includes:

[0150] a third corresponding relationship determination module, configured to determine a third corresponding relationship based on a vehicle kinematics model and according to the vehicle motion information and the yaw angular acceleration data, wherein the third corresponding relationship describes a relationship between a front axle sideslip angle change rate and the vehicle motion information and the yaw angular acceleration data;

[0151] a fourth corresponding relationship determination module, configured to determine a fourth corresponding relationship based on a tire brush model, wherein the fourth corresponding relationship describes a relationship between a rate of change of a front axle slip angle and a rate of change of a rack force;

[0152] The second corresponding relationship determining submodule is used to determine the second corresponding relationship based on the third corresponding relationship and the fourth corresponding relationship.

[0153] In an optional embodiment, the second analysis module 705 includes:

[0154] A closed-loop observer construction module, used to construct a closed-loop observer based on the first corresponding relationship and the second corresponding relationship;

[0155] The rack force analysis module is used to perform rack force analysis based on a closed-loop observer to obtain rack force data.

[0156] In an optional embodiment, the first analysis module 703 includes:

[0157] A first acceleration analysis module, used for analyzing and processing the yaw angular acceleration of the front axle side of the vehicle on the vehicle motion information to obtain first initial yaw angular acceleration data;

[0158] The second acceleration analysis module is used to analyze and process the yaw angular acceleration of the rear axle of the vehicle on the vehicle motion information to obtain second initial yaw angular acceleration data;

[0159] The averaging module is used to determine the average value of the first initial yaw angular acceleration data and the second initial yaw angular acceleration data as the yaw angular acceleration data.

[0160] In an optional embodiment, the first acceleration analysis module includes:

[0161] a fifth corresponding relationship determination module, configured to determine a fifth corresponding relationship based on a vehicle dynamics model and vehicle motion information, wherein the fifth corresponding relationship describes a relationship between a front axle lateral force and a yaw angular acceleration;

[0162] A front axle change rate information determination module, used to determine the front axle lateral force change rate information;

[0163] The first Kalman filter module is used to perform Kalman filter processing based on the fifth corresponding relationship and the front axle lateral force change rate information to obtain first initial yaw angular acceleration data.

[0164] In an optional embodiment, the second acceleration analysis module includes:

[0165] a sixth corresponding relationship determination module, configured to determine a sixth corresponding relationship based on a vehicle dynamics model and vehicle motion information, wherein the sixth corresponding relationship describes a relationship between a rear axle lateral force and a yaw angular acceleration;

[0166] A rear axle change rate information determination module, used to determine rear axle lateral force change rate information;

[0167] The second Kalman filter module is used to perform Kalman filter processing based on the sixth corresponding relationship and the rear axle lateral force change rate information to obtain second initial yaw angular acceleration data.

[0168] In an optional embodiment, the device further comprises:

[0169] A first filtering module, used for performing a first-order low-pass filtering process on the rack force data based on a first frequency band to obtain a first target rack force;

[0170] a second filtering module, configured to perform a first-order low-pass filtering process on the rack force data based on a second frequency band to obtain a second target rack force, wherein a cutoff frequency corresponding to the second frequency band is less than a cutoff frequency corresponding to the second frequency band, and the second target rack force represents the rack force caused by the driver's operation;

[0171] a subtraction module, used for subtracting the second target rack force from the first target rack force to obtain a third target rack force, the third target rack force being a rack force caused by the excitation of the rough road surface;

[0172] The third filtering module is used to perform a second-order bandpass filtering process on the rack force data based on the third frequency band to obtain a fourth target rack force. The cutoff frequency corresponding to the third frequency band is less than the cutoff frequency corresponding to the first frequency band and greater than the cutoff frequency corresponding to the second frequency band. The fourth target rack force represents the rack force caused by the excitation of potholes in the road surface.

[0173] In the embodiments of the present application, the term "module" or "unit" refers to a computer program or a part of a computer program with a predetermined function, and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware such as processing circuits or memories, or a combination thereof. Similarly, one processor or multiple processors or memories can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0174] In an exemplary embodiment, an electronic device is also provided, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is used for the instructions to implement the rack force observation method of the wire-controlled steering system as in the embodiment of the present disclosure.

[0175] Figure 8 is a block diagram of an electronic device for observing rack force of a wire steering system according to an exemplary embodiment. The electronic device may be a terminal, and its internal structure diagram may be as shown in FIG. Figure 8 As shown. The electronic device includes a processor, a memory, a network interface, a display screen and an input device connected via a system bus. Among them, the processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the electronic device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a rack force observation method for a wire-controlled steering system is implemented. The display screen of the electronic device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the electronic device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the housing of the electronic device, or an external keyboard, touchpad or mouse, etc.

[0176] Those skilled in the art will understand that Figure 8The structure shown in the figure is merely a block diagram of a partial structure related to the scheme of the present disclosure, and does not constitute a limitation on the electronic device to which the scheme of the present disclosure is applied. The specific electronic device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0177] In an exemplary embodiment, a storage medium is also provided. When instructions in the storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the rack force observation method of the wire-controlled steering system in the embodiment of the present disclosure.

[0178] In an exemplary embodiment, a computer program product including instructions is also provided. When the computer program product is run on a computer, the computer is enabled to execute the rack force observation method of the steer-by-wire system in the embodiment of the present disclosure.

[0179] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present disclosure can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0180] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the claims.

[0181] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A rack force observation method for a wire-controlled steering system, characterized in that: The method comprises: Obtain vehicle motion information and state information corresponding to the steer-by-wire system; Based on the steering system mechanical model, determining a first corresponding relationship according to the state information, wherein the first corresponding relationship describes a relationship between the rack force and the state information; Performing yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data; Performing kinematic analysis on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, wherein the second corresponding relationship describes a relationship between a rack force change rate and the vehicle motion information and the yaw angular acceleration data; Rack force analysis is performed based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

2. The method according to claim 1, characterized in that The kinematic analysis of the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship includes: Based on the vehicle kinematics model, determining a third corresponding relationship according to the vehicle motion information and the yaw angular acceleration data, wherein the third corresponding relationship describes a relationship between a front axle sideslip angle change rate and the vehicle motion information and the yaw angular acceleration data; Based on the tire brush model, determining a fourth corresponding relationship, wherein the fourth corresponding relationship describes a relationship between a rate of change of the front axle slip angle and a rate of change of the rack force; Based on the third corresponding relationship and the fourth corresponding relationship, the second corresponding relationship is determined.

3. The method according to claim 1, characterized in that The performing rack force analysis based on the first corresponding relationship and the second corresponding relationship to obtain rack force data includes: Based on the first corresponding relationship and the second corresponding relationship, construct a closed-loop observer; Rack force analysis and processing is performed based on the closed-loop observer to obtain rack force data.

4. The method according to claim 1, characterized in that The performing yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data includes: Performing yaw angular acceleration analysis on the front axle side of the vehicle on the vehicle motion information to obtain first initial yaw angular acceleration data; Performing yaw angular acceleration analysis on the vehicle rear axle side of the vehicle motion information to obtain second initial yaw angular acceleration data; An average value of the first initial yaw angular acceleration data and the second initial yaw angular acceleration data is determined as the yaw angular acceleration data.

5. The method according to claim 4, characterized in that The performing yaw angular acceleration analysis processing on the vehicle front axle side of the vehicle motion information to obtain first initial yaw angular acceleration data includes: Based on the vehicle dynamics model, determining a fifth corresponding relationship according to the vehicle motion information, wherein the fifth corresponding relationship describes a relationship between a front axle lateral force and a yaw angular acceleration; Determine the front axle lateral force change rate information; Based on the fifth corresponding relationship and the front axle lateral force change rate information, Kalman filtering is performed to obtain first initial yaw angular acceleration data.

6. The method according to claim 4, characterized in that The performing yaw angular acceleration analysis processing on the rear axle side of the vehicle on the vehicle motion information to obtain second initial yaw angular acceleration data includes: Based on the vehicle dynamics model, determining a sixth corresponding relationship according to the vehicle motion information, the sixth corresponding relationship describing a relationship between a rear axle lateral force and a yaw angular acceleration; Determine rear axle lateral force change rate information; Based on the sixth corresponding relationship and the rear axle lateral force change rate information, Kalman filtering processing is performed to obtain the second initial yaw angular acceleration data.

7. The method according to claim 1, characterized in that The method further comprises: Performing a first-order low-pass filtering process based on a first frequency band on the rack force data to obtain a first target rack force; performing a first-order low-pass filtering process based on a second frequency band on the rack force data to obtain a second target rack force, wherein a cutoff frequency corresponding to the second frequency band is less than a cutoff frequency corresponding to the second frequency band, and the second target rack force represents a rack force caused by a driver operation; Subtracting the second target rack force from the first target rack force to obtain a third target rack force, wherein the third target rack force is a rack force caused by excitation of a rough road surface; The rack force data is subjected to a second-order bandpass filtering process based on a third frequency band to obtain a fourth target rack force, wherein a cutoff frequency corresponding to the third frequency band is smaller than a cutoff frequency corresponding to the first frequency band and larger than a cutoff frequency corresponding to the second frequency band, and the fourth target rack force represents the rack force caused by excitation of potholes in the road surface.

8. A rack force observation device for a wire-controlled steering system, characterized in that: The device comprises: An acquisition module, used to acquire vehicle motion information and state information corresponding to the wire-controlled steering system; A first corresponding relationship determining module, configured to determine a first corresponding relationship according to the state information based on a steering system mechanical model, wherein the first corresponding relationship describes a relationship between the rack force and the state information; A first analysis module, configured to perform yaw angular acceleration analysis on the vehicle motion information to obtain yaw angular acceleration data; a second corresponding relationship determination module, configured to perform kinematic analysis on the vehicle motion information and the yaw angular acceleration data to obtain a second corresponding relationship, wherein the second corresponding relationship describes a relationship between a rack force change rate and the vehicle motion information and the yaw angular acceleration data; The second analysis module is used to perform rack force analysis based on the first corresponding relationship and the second corresponding relationship to obtain rack force data.

9. An electronic device, characterized in that: include: processor; a memory for storing instructions executable by the processor; Wherein, the processor is used for the instructions to implement the rack force observation method of the wire-controlled steering system as described in any one of claims 1 to 7.

10. A storage medium, characterized in that: When the instructions in the storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the rack force observation method of a steer-by-wire system as claimed in any one of claims 1 to 7.

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