Steering angle control method and system of magnetic screw integrated steer-by-wire system

Abstract

The application provides a steering angle control method and system of a magnetic screw integrated steer-by-wire system. The method comprises the following steps: acquiring real-time running data and a reference steering angle of the magnetic screw integrated steer-by-wire system, and performing filtering processing on the running data, wherein the real-time running data comprises a real-time steering angle and a real-time steering angular velocity of a steering wheel, a real-time magnetic thrust of a magnetic screw, a real-time rotating speed and a real-time torque of a driving motor; calculating a reference torque of the driving motor according to the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time rotating speed and the real-time torque of the driving motor, and the reference steering angle; and controlling the steering angle of the magnetic screw integrated steer-by-wire system based on the reference torque of the driving motor. According to the technical scheme, disturbances are estimated and compensated in real time, the robustness of the magnetic screw integrated steer-by-wire system is greatly improved, and the system has high universality and high control precision.

Description

Technical Field

[0001] This application relates to the field of automotive steering, and in particular to a steering angle control method and system for a magnetic screw integrated steer-by-wire system. Background Technology

[0002] Steer-by-wire systems have become a hot research topic in the automotive industry, offering significant potential for improving vehicle handling and stability. Steer-by-wire systems typically combine a drive motor with a mechanical transmission to achieve autonomous steering. However, the inherent mechanical characteristics of the mechanical transmission in steer-by-wire systems, such as friction, wear, aging, and jamming, severely compromise the reliability, efficiency, and control performance of these systems.

[0003] To eliminate the negative impact of mechanical transmission devices in steer-by-wire systems, the author invented a magnetic lead screw integrated steer-by-wire system. This system uses a novel magnetic lead screw to achieve the rotational-linear motion conversion of the steer-by-wire system, avoiding the negative effects of traditional mechanical transmission mechanisms. However, the introduction of the magnetic lead screw brings a new magnetic element to the steer-by-wire system, altering its mathematical model and posing new challenges to its precision control.

[0004] Currently, there is a lack of development in the control of magnetic screw integrated steer-by-wire systems. Furthermore, traditional steer-by-wire systems based on mechanical transmission devices differ significantly from magnetic screw integrated steer-by-wire systems in terms of system model, making it difficult to directly apply steering angle control methods and systems. Summary of the Invention

[0005] This application provides a steering angle control method and system for a magnetic screw integrated steer-by-wire system, which at least solves the technical problem that existing traditional steer-by-wire control methods and systems are difficult to directly apply to magnetic screw integrated steer-by-wire systems.

[0006] The first aspect of this application proposes a steering angle control method for a magnetic screw integrated steer-by-wire system, the method comprising:

[0007] The system acquires real-time operating data and reference steering angle of the magnetic screw integrated steer-by-wire system, and filters the operating data. The real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor.

[0008] The reference torque of the drive motor is calculated based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle.

[0009] The steering angle of the magnetic lead screw integrated steer-by-wire system is controlled based on the reference torque of the drive motor.

[0010] Preferably, the step of calculating the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the lead screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle includes:

[0011] The steering angle error of the steering wheel is calculated based on the real-time steering angle of the steering wheel after filtering and the reference steering angle.

[0012] The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary;

[0013] The reference magnetic thrust of the magnetic lead screw is calculated based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel.

[0014] The reference speed of the drive motor is calculated based on the real-time magnetic thrust of the magnetic lead screw after filtering and the reference magnetic thrust of the magnetic lead screw.

[0015] The reference torque of the drive motor is calculated based on the real-time speed of the drive motor after filtering and the reference speed of the drive motor.

[0016] Furthermore, the step of calculating the steering angle error of the steering wheel based on the filtered real-time steering angle and the reference steering angle includes:

[0017] Calculate the difference between the reference steering angle and the real-time steering angle of the steering wheel after filtering, and use the difference as the steering angle error of the steering wheel.

[0018] Furthermore, the step of calculating the reference steering angular velocity of the steering wheel based on the steering angle error and a preset steering angle quantization error boundary includes:

[0019] Obtain the preset steering angle quantization error boundary;

[0020] The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary.

[0021] Furthermore, the step of calculating the reference magnetic thrust of the magnetic lead screw based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel includes:

[0022] Obtain the preset quantization error boundary of the steering angular velocity and the real-time estimate of the lumped disturbance term of the steering angular velocity;

[0023] The reference steering angular velocity of the steering wheel is filtered to obtain the filtered reference steering angular velocity of the steering wheel.

[0024] Calculate the difference between the reference steering angular velocity of the steering wheel after filtering and the real-time steering angular velocity after filtering, and use the difference as the steering angular velocity error;

[0025] The reference magnetic thrust of the magnetic lead screw is calculated based on the preset quantization error boundary of the steering angular velocity, the real-time estimate of the lumped disturbance term of the steering angular velocity, and the steering angular velocity error.

[0026] Furthermore, the step of calculating the reference speed of the drive motor based on the real-time magnetic thrust of the filtered magnetic lead screw and the reference magnetic thrust of the magnetic lead screw includes:

[0027] Obtain the preset quantization error boundary of the magnetic screw thrust and the real-time estimate of the lumped disturbance term of the magnetic screw thrust;

[0028] The reference magnetic thrust of the magnetic lead screw is filtered to obtain the filtered reference magnetic thrust of the magnetic lead screw.

[0029] Calculate the difference between the reference magnetic thrust of the magnetic screw after filtering and the real-time magnetic thrust of the magnetic screw after filtering, and use the difference as the magnetic thrust error of the magnetic screw.

[0030] The reference speed of the drive motor is calculated based on the preset quantization error boundary of the magnetic screw thrust, the real-time estimate of the lumped disturbance term of the magnetic screw thrust, and the magnetic screw thrust error.

[0031] Furthermore, the step of calculating the reference torque of the drive motor based on the filtered real-time speed of the drive motor and the reference speed of the drive motor includes:

[0032] Obtain the preset quantization error boundary of the drive motor speed and the real-time estimate of the lumped disturbance term of the drive motor speed, wherein the real-time estimate of the lumped disturbance term of the drive motor speed is based on real-time torque calculation;

[0033] The reference speed of the drive motor is filtered to obtain the filtered reference speed of the drive motor;

[0034] The difference between the reference speed of the drive motor after filtering and the real-time speed of the drive motor after filtering is calculated, and the difference is used as the speed error of the drive motor.

[0035] The reference torque of the drive motor is calculated based on the preset quantization error boundary of the drive motor speed, the real-time estimate of the lumped disturbance term of the drive motor speed, and the speed error of the drive motor.

[0036] A second aspect of this application provides a steering angle control system for a magnetic lead screw integrated steer-by-wire system, comprising:

[0037] The acquisition module is used to acquire real-time operating data and reference steering angle of the magnetic screw integrated steer-by-wire system, and to filter the operating data. The real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor.

[0038] The calculation module is used to calculate the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle.

[0039] The control module is used to control the steering angle of the magnetic screw integrated steer-by-wire system based on the reference torque of the drive motor.

[0040] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the method described in the first aspect embodiment.

[0041] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method described in the first aspect.

[0042] The technical solutions provided by the embodiments of this application have at least the following beneficial effects:

[0043] This application proposes a steering angle control method and system for a magnetic screw integrated steer-by-wire system. The method includes: acquiring real-time operating data and a reference steering angle of the magnetic screw integrated steer-by-wire system; filtering the operating data, wherein the real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor; calculating the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, real-time speed and real-time torque of the drive motor, and the reference steering angle; and controlling the steering angle of the magnetic screw integrated steer-by-wire system based on the reference torque of the drive motor. The technical solution proposed in this application fills the gap in the development of control methods for magnetic screw integrated steer-by-wire systems. Furthermore, it estimates and compensates for disturbances in real time, significantly improving the robustness of the magnetic screw integrated steer-by-wire system, exhibiting strong versatility and high control accuracy.

[0044] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0045] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0046] Figure 1 This is a flowchart illustrating a steering angle control method for a magnetic lead screw integrated steer-by-wire system according to an embodiment of this application;

[0047] Figure 2 This is a structural diagram of a steering angle control system for a magnetic screw integrated steer-by-wire system according to an embodiment of this application;

[0048] Figure 3 This is a structural diagram of a computing module provided according to an embodiment of this application;

[0049] Figure 4 This is a structural diagram of a constraint-robust steering angle control unit provided according to an embodiment of this application;

[0050] Figure 5 This is a structural diagram of a constraint-robust steering angular velocity control unit according to an embodiment of this application;

[0051] Figure 6 This is a structural diagram of a constraint-robust magnetic thrust control unit provided according to an embodiment of this application;

[0052] Figure 7This is a structural diagram of a constraint-robust speed control unit provided according to an embodiment of this application;

[0053] Figure 8 This is a structural diagram of a magnetic lead screw integrated steer-by-wire system according to an embodiment of this application.

[0054] Figure Labels

[0055] The system includes: acquisition module 100, calculation module 200, control module 300, first calculation unit 201, constraint robust steering angle control unit 202, constraint robust steering angular velocity control unit 203, constraint robust magnetic thrust control unit 204, constraint robust speed control unit 205, steering angle error calculation module 831, steering angle constraint module 832, steering angle control module 833, reference steering angular velocity filtering module 834, steering angular velocity error calculation module 841, steering angular velocity constraint module 842, and steering angular velocity disturbance observation module 843. Steering angular velocity control module 844, reference magnetic thrust filtering module 845, magnetic thrust error calculation module 851, magnetic thrust constraint module 852, magnetic thrust disturbance observation module 853, magnetic thrust control module 844, reference speed filtering module 855, speed error calculation module 861, speed constraint module 86, speed disturbance observation module 863, speed control module 864, reference torque limiting module 865, steering wheel 1, steering column 2, road feel motor 3, drive motor 4, magnet 5, steering tie rod 6, steering wheel 7, steering control system 8. Detailed Implementation

[0056] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0057] This application proposes a steering angle control method and system for a magnetic screw integrated steer-by-wire system. The method includes: acquiring real-time operating data and a reference steering angle of the magnetic screw integrated steer-by-wire system; filtering the operating data, wherein the real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor; calculating the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, real-time speed and real-time torque of the drive motor, and the reference steering angle; and controlling the steering angle of the magnetic screw integrated steer-by-wire system based on the reference torque of the drive motor. The technical solution proposed in this application fills the gap in the development of control methods for magnetic screw integrated steer-by-wire systems. Furthermore, it estimates and compensates for disturbances in real time, significantly improving the robustness of the magnetic screw integrated steer-by-wire system, exhibiting strong versatility and high control accuracy.

[0058] The following description, with reference to the accompanying drawings, illustrates a method and system for controlling the steering angle of a magnetic lead screw integrated steer-by-wire system according to embodiments of this application.

[0059] Example 1

[0060] Figure 1 This is a flowchart illustrating a steering angle control method for a magnetic screw-integrated steer-by-wire system according to an embodiment of this application, as shown below. Figure 1 As shown, the method includes:

[0061] Step 1: Acquire the real-time operating data and reference steering angle of the magnetic screw integrated steer-by-wire system, and filter the operating data. The real-time operating data includes the real-time steering angle θ of the steering wheels. sw and real-time steering angular velocity Real-time magnetic thrust F of the magnetic lead screw t Real-time speed of the drive motor and real-time torque.

[0062] It should be noted that before step 1, the following steps are also included: powering on and initializing the magnetic screw integrated steer-by-wire system.

[0063] Before step 2 and after step 1, the following is also included: constructing an analytical mathematical model of the magnetic screw integrated steer-by-wire system.

[0064] The calculation formula of the analytical mathematical model is as follows:

[0065]

[0066] Where, x1=θ sw , x3=Ft and These are the steering wheel angle, steering wheel angular velocity, magnetic thrust of the magnetic screw, and drive motor speed of the integrated magnetic screw-based steering system. D2=ξ2-(T f +T Mz ) / J sw D3 = ξ3 and D4 = ξ4 are the lumped disturbance terms of the steering wheel angular velocity, the magnetic thrust of the lead screw, and the speed of the drive motor, respectively; where It is the Coulomb friction torque of the steering wheel, F s It is the amplitude of the Coulomb friction force, sign() is the sign function, T Mz ξ1 represents the return torque of the steering wheel, and ξ2, ξ3, and ξ4 represent the unmodeled dynamics of the steering wheel angular velocity, the magnetic thrust of the lead screw, and the speed of the drive motor, respectively. sw and B sw These are the moment of inertia and coefficient of friction of the steering wheel, respectively; i s It refers to the speed ratio of the reducer; It is the equivalent stiffness of the magnetic thrust of the magnetic lead screw, F m It is the amplitude of the magnetic thrust of the magnetic lead screw, τ p It refers to the pole pitch of the magnetic lead screw; L and R p These are the lead of the magnetic lead screw and the proportional coefficient between the linear displacement of the magnetic lead screw mover and the rotation angle of the steering wheel; J m and B m These are the moment of inertia and coefficient of friction of the drive motor, respectively; T m It is the torque of the drive motor.

[0067] Step 2: Calculate the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle.

[0068] In this embodiment of the disclosure, step 2 specifically includes:

[0069] Step 2-1: Calculate the steering angle error of the steering wheel based on the real-time steering angle of the steering wheel after filtering and the reference steering angle;

[0070] Furthermore, step 2-1 specifically includes:

[0071] Calculate the difference between the reference steering angle and the real-time steering angle of the steering wheel after filtering, and use the difference as the steering angle error of the steering wheel.

[0072] Specifically, the steering angle error calculation module calculates the steering angle control error of the steering wheels in real time, using the following formula:

[0073] e1 = x 1d -x1

[0074] Among them, e1 and x 1d These are the steering wheel angle error and the reference steering angle, respectively, where the reference steering angle is set according to the driver's steering needs.

[0075] Step 2-2: Calculate the reference steering angular velocity of the steering wheel based on the steering angle error and the preset steering angle quantization error boundary;

[0076] Furthermore, step 2-2 specifically includes:

[0077] Obtain the preset steering angle quantization error boundary;

[0078] The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary.

[0079] Specifically, a fixed-time constraint robust control method is adopted, in which the constraint robust steering angle control unit calculates the reference steering angular velocity of the steering wheel online, including the following steps:

[0080] Step S2-2-1: The steering angle error calculation module calculates the steering angle control error of the steering wheel in real time. The specific formula is as follows:

[0081] e1 = x 1d -x1

[0082] Among them, e1 and x 1d These are the steering wheel angle error and the reference steering angle, respectively, where the reference steering angle is set according to the driver's steering needs.

[0083] Step S2-2-2: The steering angle constraint module defines the quantization error boundary of the steering wheel steering angle. The specific formula is as follows:

[0084]

[0085] Where φ1(t) is the steering angle constraint performance function of the steering wheel, φ 10 φ 1∞ and These are the initial value, final value, and convergence rate of the steering angle constraint performance function, respectively.

[0086] Step S2-2-3: The steering angle control module calculates the reference steering angular velocity of the steering wheel online based on the steering angle error and the steering angle quantization error boundary. The specific formula is as follows:

[0087]

[0088] in, It is the first derivative of the reference steering angle x1d; It is the first derivative of the steering angle constraint performance function φ1(t); x 2c It is the reference steering angular velocity of the steering wheel, z1=e1(φ1(t)-|e1|) -1 The steering angle funnel error variable is Φ1=φ1(t)(φ1(t)-|e1|). -2 It is an intermediate variable. i = 1, 2, 3, 4; j = 1, 2 is a sign exponential function, α c11 >0, β c11 >0、0<λ c11 <1 and χ c11 >1 is a positive constant.

[0089] Step S2-2-4: The reference steering angular velocity filtering module performs first-order filtering on the reference steering angular velocity of the steering wheel. The specific formula is as follows:

[0090]

[0091] in, Filtered reference steering angular velocity x of the steering wheel 2d The first derivative, x 2d It is the filtered reference steering angular velocity of the steering wheel, τ f2 >0、0<λ f2 <1 and χ f2 >1 is a positive constant.

[0092] Steps 2-3: Calculate the reference magnetic thrust of the magnetic lead screw based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel;

[0093] Furthermore, steps 2-3 specifically include:

[0094] Obtain the preset quantization error boundary of the steering angular velocity and the real-time estimate of the lumped disturbance term of the steering angular velocity;

[0095] The reference steering angular velocity of the steering wheel is filtered to obtain the filtered reference steering angular velocity of the steering wheel.

[0096] Calculate the difference between the reference steering angular velocity of the steering wheel after filtering and the real-time steering angular velocity after filtering, and use the difference as the steering angular velocity error;

[0097] The reference magnetic thrust of the magnetic lead screw is calculated based on the preset quantization error boundary of the steering angular velocity, the real-time estimate of the lumped disturbance term of the steering angular velocity, and the steering angular velocity error.

[0098] Specifically, a fixed-time constraint robust control method is adopted, and the constraint robust steering angular velocity control unit calculates the reference magnetic thrust of the magnetic lead screw online, which includes the following steps:

[0099] Step S2-3-1: The steering angular velocity error calculation module calculates the steering wheel's steering angular velocity control error in real time. The specific formula is as follows:

[0100] e2=x 2d -x2

[0101] Where e2 is the steering angular velocity error of the steering wheel.

[0102] Step S2-3-2: The steering angular velocity constraint module defines the quantization error boundary of the steering wheel's steering angular velocity. The specific formula is as follows:

[0103]

[0104] Where φ2(t) is the steering angular velocity constraint performance function of the steering wheel, φ 20 φ 2∞ and These are the initial value, final value, and convergence rate of the steering angular velocity constraint performance function, respectively.

[0105] Step S2-3-3: The steering angular velocity disturbance observation module observes the lumped disturbance term of the steering wheel's steering angular velocity in real time. The specific formula is as follows:

[0106]

[0107] in, It is an estimate of the steering angular velocity of the steering wheel. The first derivative; Estimate of the lumped disturbance term of steering angular velocity The first derivative. and These are the estimated values ​​of the steering wheel angular velocity and the estimated value of the lumped disturbance term of the steering angular velocity, respectively. This is the estimation error of the steering wheel's angular velocity. α o21 >0、α o22 >0, β o21 >0, β o22 >0、0<λ o21 <1、0<λ o22 <1、χ o21 >1、χ o22 >1 and Λ o2 >0 is a positive integer.

[0108] Step S2-3-4: The steering angular velocity control module calculates the reference magnetic thrust of the lead screw online based on the steering angular velocity error of the steering wheel, the steering angular velocity quantization error boundary, and the estimated value of the lumped disturbance term of the steering angular velocity. The specific formula is as follows:

[0109]

[0110] in, Filtered reference steering angular velocity x of the steering wheel 2d The first derivative; It is the first derivative of the steering angular velocity constraint performance function φ2(t). 3c It is the reference magnetic thrust of the magnetic lead screw, z2=e2(φ2(t)-|e2|) -1 The steering angular velocity funnel error variable is Φ2=φ2(t)(φ2(t)-|e2|). -2 It is an intermediate variable, α c21 >0, β c21 >0、0<λ c21 <1 and χ c21 >1 is a positive constant.

[0111] Step S2-3-5: The reference magnetic thrust filtering module performs first-order filtering on the reference magnetic thrust of the magnetic lead screw. The specific formula is as follows:

[0112]

[0113] in, The reference magnetic thrust x of the filtered magnetic screw 3d The first derivative of x. 3d It is the reference magnetic thrust of the filtered magnetic lead screw, τ f3 >0、0<λ f3 <1 and χ f3 >1 is a positive constant.

[0114] Steps 2-4: Calculate the reference speed of the drive motor based on the real-time magnetic thrust of the magnetic lead screw after filtering and the reference magnetic thrust of the magnetic lead screw;

[0115] Furthermore, steps 2-4 specifically include:

[0116] Obtain the preset quantization error boundary of the magnetic screw thrust and the real-time estimate of the lumped disturbance term of the magnetic screw thrust;

[0117] The reference magnetic thrust of the magnetic lead screw is filtered to obtain the filtered reference magnetic thrust of the magnetic lead screw.

[0118] Calculate the difference between the reference magnetic thrust of the magnetic screw after filtering and the real-time magnetic thrust of the magnetic screw after filtering, and use the difference as the magnetic thrust error of the magnetic screw.

[0119] The reference speed of the drive motor is calculated based on the preset quantization error boundary of the magnetic screw thrust, the real-time estimate of the lumped disturbance term of the magnetic screw thrust, and the magnetic screw thrust error.

[0120] Specifically, a fixed-time constraint robust control method is adopted, in which the constraint robust magnetic thrust control unit calculates the reference speed of the drive motor online, including the following steps:

[0121] Step S2-4-1: The magnetic thrust error calculation module calculates the magnetic thrust control error of the magnetic lead screw in real time. The specific formula is as follows:

[0122] e3 = x 3d -x3

[0123] Where e3 is the magnetic thrust error of the magnetic lead screw.

[0124] Step S2-4-2: The magnetic thrust constraint module defines the quantization error boundary of the magnetic screw thrust. The specific formula is as follows:

[0125]

[0126] Where φ3(t) is the magnetic thrust constraint performance function of the magnetic lead screw, φ 30 φ 3∞ and These are the initial value, final value, and convergence rate of the magnetic thrust constraint performance function, respectively.

[0127] Step S2-4-3: The magnetic thrust disturbance observation module observes the lumped disturbance term of the magnetic screw thrust in real time. The specific formula is as follows:

[0128]

[0129] in, It is an estimated value of the magnetic thrust of the magnetic lead screw. The first derivative; It is an estimate of the lumped disturbance term of magnetic thrust. The first derivative. and These are the estimated values ​​of the magnetic thrust of the magnetic lead screw and the estimated value of the lumped disturbance term of the magnetic thrust, respectively. This is the estimation error of the magnetic thrust of the magnetic lead screw. α o31 >0、α o32 >0, β o31 >0, β o32 >0、0<λo31 <1、0<λ o32 <1、χ o31 >1、χ o32 >1 and Λ o3 >0 is a positive integer.

[0130] Step S2-4-4: The magnetic thrust control module calculates the reference speed of the drive motor online based on the estimated value of the magnetic thrust error of the magnetic lead screw, the quantitative error boundary of the magnetic thrust, and the lumped disturbance term of the magnetic thrust. The specific formula is as follows:

[0131]

[0132] in, It is the first derivative of the magnetic thrust constraint performance function φ3(t); The reference magnetic thrust x of the filtered magnetic screw 3d The first derivative of x. 4c This is the reference speed of the drive motor, z3=e3(φ3(t)-|e3|). -1 It is the magnetic thrust funnel error variable, Φ3=φ3(t)(φ3(t)-|e3|) -2 It is an intermediate variable, α c31 >0, β c31 >0、0<λ c31 <1 and χ c31 >1 is a positive constant.

[0133] Step S2-4-5: The reference speed filtering module performs first-order filtering on the reference speed of the drive motor. The specific formula is as follows:

[0134]

[0135] in, The reference magnetic thrust x of the filtered magnetic screw 4d The first derivative of x. 4d It is the reference magnetic thrust of the filtered magnetic lead screw, τ f4 >0、0<λ f4 <1 and χ f4 >1 is a positive constant.

[0136] Steps 2-5: Calculate the reference torque of the drive motor based on the real-time speed of the drive motor after filtering and the reference speed of the drive motor.

[0137] Furthermore, steps 2-5 specifically include:

[0138] Obtain the preset quantization error boundary of the drive motor speed and the real-time estimate of the lumped disturbance term of the drive motor speed, wherein the real-time estimate of the lumped disturbance term of the drive motor speed is based on real-time torque calculation;

[0139] The reference speed of the drive motor is filtered to obtain the filtered reference speed of the drive motor;

[0140] The difference between the reference speed of the drive motor after filtering and the real-time speed of the drive motor after filtering is calculated, and the difference is used as the speed error of the drive motor.

[0141] The reference torque of the drive motor is calculated based on the preset quantization error boundary of the drive motor speed, the real-time estimate of the lumped disturbance term of the drive motor speed, and the speed error of the drive motor.

[0142] Specifically, a fixed-time constraint robust control method is adopted, in which the constraint robust speed control unit calculates the reference torque of the drive motor online, including the following steps:

[0143] Step S2-5-1: The speed error calculation module calculates the speed control error of the drive motor in real time. The specific formula is as follows:

[0144] e4 = x 4d -x4

[0145] Here, e4 represents the speed error of the drive motor.

[0146] Step S2-5-2: The speed constraint module defines the quantization error boundary of the drive motor speed. The specific formula is as follows:

[0147]

[0148] Where φ4(t) is the speed constraint performance function of the drive motor, φ 40 φ 4∞ and These are the initial value, final value, and convergence rate of the speed constraint performance function, respectively.

[0149] Step S2-5-3: The speed disturbance observation module observes the lumped disturbance term of the drive motor speed in real time. The specific formula is as follows:

[0150]

[0151] in, It is an estimated value of the drive motor speed. The first derivative; It is the estimated value of the lumped disturbance term of rotational speed. The first derivative, T msFor real-time torque, and These are the estimated values ​​of the drive motor speed and the estimated value of the lumped disturbance term of the speed, respectively. This is the estimation deviation of the drive motor speed. α o41 >0、α o42 >0, β o41 >0, β o42 >0、0<λ o41 <1、0<λ o42 <1、χ o41 >1、χ o42 >1 and Λ o4 >0 is a positive integer.

[0152] Step S2-5-4: The speed control module calculates the reference torque of the drive motor online based on the estimated values ​​of the drive motor speed error, speed quantization error boundary, and speed lumped disturbance term. The specific formula is as follows:

[0153]

[0154] in, The reference magnetic thrust x of the filtered magnetic screw 4d The first derivative; This is the first derivative of the speed constraint performance function φ4(t) of the drive motor. z4 = e4(φ4(t) - |e4|) -1 It is the rotational speed funnel error variable, Φ4=φ4(t)(φ4(t)-|e4|) -2 It is an intermediate variable, α c41 >0, β c41 >0、0<λ c41 <1 and χ c41 >1 is a positive constant.

[0155] Step S2-5-5: The reference torque limiting module limits the amplitude and slope of the reference torque of the drive motor.

[0156] It should be noted that the calculation in step 2 is based on the constructed analytical mathematical model.

[0157] Step 3: Control the steering angle of the magnetic lead screw integrated steering system based on the reference steering angular velocity, the reference magnetic thrust of the magnetic lead screw, the reference speed of the drive motor, and the reference torque of the drive motor.

[0158] It should be noted that: 1. The steering angle control method for the magnetic screw integrated steer-by-wire system provided by this invention adopts a fixed-time constraint robust backstepping control method, achieving dynamic steering angle control of the magnetic screw integrated steer-by-wire system for the first time, filling the gap in the development of control methods for magnetic screw integrated steer-by-wire systems. 2. The steering angle control method for the magnetic screw integrated steer-by-wire system provided by this invention establishes a precise mathematical model of the magnetic screw integrated steer-by-wire system for the first time; based on this, a fixed-time extended state observer is constructed to estimate system disturbances in real time and compensate for them in real time, significantly improving the robustness of the magnetic screw integrated steer-by-wire system. 3. The steering angle control method for the magnetic screw integrated steer-by-wire system provided by this invention integrates the steering angle and steering angular velocity constraints of the steering wheels, the magnetic thrust constraints of the magnetic screw, and the speed constraints of the drive motor into the development of the control algorithm for the magnetic screw integrated steer-by-wire system for the first time, achieving steering angle control with specified performance; at the same time, it achieves steering angle control with specified time convergence using a fixed-time control method. The proposed method significantly improves the steering angle control performance of the magnetic screw integrated steer-by-wire system, making it suitable for applications with specific control precision and response time requirements.

[0159] In summary, the steering angle control method for a magnetic screw integrated steer-by-wire system proposed in this embodiment fills the gap in the development of control methods for magnetic screw integrated steer-by-wire systems. At the same time, it estimates and compensates for disturbances in real time, which greatly improves the robustness of the magnetic screw integrated steer-by-wire system. It has strong versatility and high control accuracy.

[0160] Example 2

[0161] Figure 2 This is a structural diagram of a steering angle control system for a magnetic screw integrated steer-by-wire system according to an embodiment of this application, as shown below. Figure 2 As shown, the system includes:

[0162] The acquisition module 100 is used to acquire real-time operating data and reference steering angle of the magnetic screw integrated steer-by-wire system, and to filter the operating data. The real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor.

[0163] The calculation module 200 is used to calculate the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle.

[0164] The control module 300 is used to control the steering angle of the magnetic screw integrated steer-by-wire system based on the reference torque of the drive motor.

[0165] In the embodiments disclosed herein, such as Figure 3 As shown, the computing module 200 includes:

[0166] The first calculation unit 201 is used to calculate the steering angle error of the steering wheel based on the filtered real-time steering angle of the steering wheel and the reference steering angle.

[0167] The constraint-robust steering angle control unit 202 is used to calculate the reference steering angular velocity of the steering wheel based on the steering angle error and a preset steering angle quantization error boundary;

[0168] The constraint-robust steering angular velocity control unit 203 is used to calculate the reference magnetic thrust of the magnetic lead screw based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel.

[0169] The constraint-robust magnetic thrust control unit 204 is used to calculate the reference speed of the drive motor based on the real-time magnetic thrust of the magnetic lead screw after filtering and the reference magnetic thrust of the magnetic lead screw.

[0170] The constraint-robust speed control unit 205 is used to calculate the reference torque of the drive motor based on the real-time speed of the drive motor after filtering and the reference speed of the drive motor.

[0171] Furthermore, the first computing unit 201 is also used for:

[0172] Calculate the difference between the reference steering angle and the real-time steering angle of the steering wheel after filtering, and use the difference as the steering angle error of the steering wheel.

[0173] Furthermore, the constraint-robust steering angle control unit 202 is also used for:

[0174] Obtain the preset steering angle quantization error boundary;

[0175] The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary.

[0176] Specifically, such as Figure 4As shown, the constraint-robust steering angle control unit 202 includes: a steering angle error calculation module 831, a steering angle constraint module 832, a steering angle control module 833, and a reference steering angular velocity filtering module 834. The steering angle error calculation module 831 is used to calculate the steering angle control error of the steering wheel 7 online; the steering angle constraint module 832 is used to define the steering angle quantization error boundary of the steering wheel 7; the steering angle control module 833 calculates the reference steering angular velocity of the steering wheel 7 based on the steering angle control error and the steering angle quantization error boundary; and the reference steering angular velocity filtering module 834 performs first-order filtering on the reference steering angular velocity of the steering wheel 7.

[0177] Furthermore, the constraint-robust steering angular velocity control unit 203 is also used for:

[0178] Obtain the preset quantization error boundary of the steering angular velocity and the real-time estimate of the lumped disturbance term of the steering angular velocity;

[0179] The reference steering angular velocity of the steering wheel is filtered to obtain the filtered reference steering angular velocity of the steering wheel.

[0180] Calculate the difference between the reference steering angular velocity of the steering wheel after filtering and the real-time steering angular velocity after filtering, and use the difference as the steering angular velocity error;

[0181] The reference magnetic thrust of the magnetic lead screw is calculated based on the preset quantization error boundary of the steering angular velocity, the real-time estimate of the lumped disturbance term of the steering angular velocity, and the steering angular velocity error.

[0182] Specifically, such as Figure 5 As shown, the constrained robust steering angular velocity control unit 203 includes: a steering angular velocity error calculation module 841, a steering angular velocity constraint module 842, a steering angular velocity disturbance observation module 843, a steering angular velocity control module 844, and a reference magnetic thrust filtering module 845. Specifically, the steering angular velocity error calculation module 841 is used to calculate the steering angular velocity control error of the steering wheel 7 online; the steering angular velocity constraint module 842 defines the steering angular velocity quantization error boundary of the steering wheel 7; the steering angular velocity disturbance observation module 843 uses a fixed-time extended state observation method to observe the lumped disturbance term of the steering angular velocity in real time; the steering angular velocity control module 844 calculates the reference magnetic thrust of the magnetic lead screw 5 based on the steering angular velocity control error, the steering angular velocity quantization error boundary, and the estimated value of the lumped disturbance term of the steering angular velocity. The reference magnetic thrust filtering module 845 is used to perform first-order filtering on the reference magnetic thrust of the magnetic lead screw 5.

[0183] Furthermore, the constraint-robust magnetic thrust control unit 204 is also used for:

[0184] Obtain the preset quantization error boundary of the magnetic screw thrust and the real-time estimate of the lumped disturbance term of the magnetic screw thrust;

[0185] The reference magnetic thrust of the magnetic lead screw is filtered to obtain the filtered reference magnetic thrust of the magnetic lead screw.

[0186] Calculate the difference between the reference magnetic thrust of the magnetic screw after filtering and the real-time magnetic thrust of the magnetic screw after filtering, and use the difference as the magnetic thrust error of the magnetic screw.

[0187] The reference speed of the drive motor is calculated based on the preset quantization error boundary of the magnetic screw thrust, the real-time estimate of the lumped disturbance term of the magnetic screw thrust, and the magnetic screw thrust error.

[0188] Specifically, such as Figure 6 As shown, the constrained robust magnetic thrust control unit 204 includes: a magnetic thrust error calculation module 851, a magnetic thrust constraint module 852, a magnetic thrust disturbance observation module 853, a magnetic thrust control module 844, and a reference speed filtering module 855. Specifically, the magnetic thrust error calculation module 851 is used to calculate the magnetic thrust control error of the magnetic lead screw 5 online; the magnetic thrust constraint module 852 is used to define the quantization error boundary of the magnetic thrust of the magnetic lead screw 5; the magnetic thrust disturbance observation module 853 uses a fixed-time extended state observation method to observe the lumped disturbance term of the magnetic thrust in real time; the magnetic thrust control module 854 calculates the reference speed of the drive motor 4 based on the magnetic thrust control error, the quantization error boundary of the magnetic thrust, and the estimated value of the lumped disturbance term of the magnetic thrust; and the reference speed filtering module 855 is used to perform first-order filtering on the reference speed of the drive motor 4.

[0189] Furthermore, the constraint-robust speed control unit 205 is also used for:

[0190] Obtain the preset quantization error boundary of the drive motor speed and the real-time estimate of the lumped disturbance term of the drive motor speed, wherein the real-time estimate of the lumped disturbance term of the drive motor speed is based on real-time torque calculation;

[0191] The reference speed of the drive motor is filtered to obtain the filtered reference speed of the drive motor;

[0192] The difference between the reference speed of the drive motor after filtering and the real-time speed of the drive motor after filtering is calculated, and the difference is used as the speed error of the drive motor.

[0193] The reference torque of the drive motor is calculated based on the preset quantization error boundary of the drive motor speed, the real-time estimate of the lumped disturbance term of the drive motor speed, and the speed error of the drive motor.

[0194] Specifically, such as Figure 7 As shown, the constrained robust speed control unit 205 includes: a speed error calculation module 861, a speed constraint module 862, a speed disturbance observation module 863, a speed control module 864, and a reference torque limiting module 865. The speed error calculation module 861 is used to calculate the speed control error of the drive motor 4 online; the speed constraint module 862 is used to define the speed quantization error boundary of the drive motor 4; the speed disturbance observation module 863 uses a fixed-time extended state observation method to observe the lumped speed disturbance term in real time; the speed control module 864 calculates the reference torque of the drive motor 4 based on the speed control error, the speed quantization error boundary, and the estimated value of the lumped speed disturbance term. The reference torque limiting module 865 is used to limit the amplitude and slope of the reference torque of the drive motor 4.

[0195] It should be noted that, as Figure 8 The diagram shows the structure of the magnetic screw integrated steer-by-wire system involved in this invention. In the diagram, the steering wheel is 1, the steering column is 2, the road feel motor is 3, the drive motor is 4, the magnetic force is 5, the steering tie rod is 6, the steering wheel is 7, and the steering control system is 8.

[0196] It should be noted that the steering angle control system of the magnetic screw integrated steer-by-wire system provided by the present invention applies the control method of the magnetic screw integrated steer-by-wire system of the present invention, so that the control system does not completely depend on the system mathematical model, has stronger versatility and stronger applicability to complex environments; and has the steering angle control capability with specified performance and specified response time.

[0197] In summary, the steering angle control system of the magnetic screw integrated steer-by-wire system proposed in this embodiment fills the gap in the development of control methods for magnetic screw integrated steer-by-wire systems. At the same time, it estimates and compensates for disturbances in real time, which greatly improves the robustness of the magnetic screw integrated steer-by-wire system. It has strong versatility and high control accuracy.

[0198] Example 3

[0199] To implement the above embodiments, this disclosure also proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the method described in Embodiment 1.

[0200] Example 4

[0201] To implement the above embodiments, this disclosure also proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in Embodiment 1.

[0202] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0203] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0204] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for controlling the steering angle of a magnetic lead screw integrated steer-by-wire system, characterized in that, The method includes: The system acquires real-time operating data and reference steering angle of the magnetic screw integrated steer-by-wire system, and filters the operating data. The real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor. The reference torque of the drive motor is calculated based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle. The steering angle of the magnetic screw integrated steer-by-wire system is controlled based on the reference torque of the drive motor. The step of calculating the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic lead screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle includes: The steering angle error of the steering wheel is calculated based on the real-time steering angle of the steering wheel after filtering and the reference steering angle. The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary; The reference magnetic thrust of the magnetic lead screw is calculated based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel. The reference speed of the drive motor is calculated based on the real-time magnetic thrust of the magnetic lead screw after filtering and the reference magnetic thrust of the magnetic lead screw. The reference torque of the drive motor is calculated based on the real-time speed of the drive motor after filtering and the reference speed of the drive motor. The step of calculating the reference speed of the drive motor based on the real-time magnetic thrust of the filtered magnetic lead screw and the reference magnetic thrust of the magnetic lead screw includes: Obtain the preset quantization error boundary of the magnetic screw thrust and the real-time estimate of the lumped disturbance term of the magnetic screw thrust; The reference magnetic thrust of the magnetic lead screw is filtered to obtain the filtered reference magnetic thrust of the magnetic lead screw. Calculate the difference between the reference magnetic thrust of the magnetic screw after filtering and the real-time magnetic thrust of the magnetic screw after filtering, and use the difference as the magnetic thrust error of the magnetic screw. The reference speed of the drive motor is calculated based on the preset quantization error boundary of the magnetic screw thrust, the real-time estimate of the lumped disturbance term of the magnetic screw thrust, and the magnetic screw thrust error.

2. The method as described in claim 1, characterized in that, The step of calculating the steering angle error of the steering wheel based on the filtered real-time steering angle and the reference steering angle includes: Calculate the difference between the reference steering angle and the real-time steering angle of the steering wheel after filtering, and use the difference as the steering angle error of the steering wheel.

3. The method as described in claim 2, characterized in that, The step of calculating the reference steering angular velocity of the steering wheel based on the steering angle error and a preset steering angle quantization error boundary includes: Obtain the preset steering angle quantization error boundary; The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary.

4. The method as described in claim 2, characterized in that, The step of calculating the reference magnetic thrust of the lead screw based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel includes: Obtain the preset quantization error boundary of the steering angular velocity and the real-time estimate of the lumped disturbance term of the steering angular velocity; The reference steering angular velocity of the steering wheel is filtered to obtain the filtered reference steering angular velocity of the steering wheel. Calculate the difference between the reference steering angular velocity of the steering wheel after filtering and the real-time steering angular velocity after filtering, and use the difference as the steering angular velocity error; The reference magnetic thrust of the magnetic lead screw is calculated based on the preset quantization error boundary of the steering angular velocity, the real-time estimate of the lumped disturbance term of the steering angular velocity, and the steering angular velocity error.

5. The method as described in claim 2, characterized in that, The step of calculating the reference torque of the drive motor based on the real-time speed of the drive motor after filtering and the reference speed of the drive motor includes: Obtain the preset quantization error boundary of the drive motor speed and the real-time estimate of the lumped disturbance term of the drive motor speed, wherein the real-time estimate of the lumped disturbance term of the drive motor speed is based on real-time torque calculation; The reference speed of the drive motor is filtered to obtain the filtered reference speed of the drive motor; The difference between the reference speed of the drive motor after filtering and the real-time speed of the drive motor after filtering is calculated, and the difference is used as the speed error of the drive motor. The reference torque of the drive motor is calculated based on the preset quantization error boundary of the drive motor speed, the real-time estimate of the lumped disturbance term of the drive motor speed, and the speed error of the drive motor.

6. A steering angle control system for a magnetic lead screw integrated steer-by-wire system, characterized in that, The system includes: The acquisition module is used to acquire real-time operating data and reference steering angle of the magnetic screw integrated steer-by-wire system, and to filter the operating data. The real-time operating data includes: real-time steering angle and real-time steering angular velocity of the steering wheel, real-time magnetic thrust of the magnetic screw, and real-time speed and real-time torque of the drive motor. The calculation module is used to calculate the reference torque of the drive motor based on the filtered real-time steering angle and real-time steering angular velocity of the steering wheel, the real-time magnetic thrust of the magnetic screw, the real-time speed and real-time torque of the drive motor, and the reference steering angle. A control module is used to control the steering angle of the magnetic screw integrated steer-by-wire system based on the reference torque of the drive motor. The calculation module is further used for: The steering angle error of the steering wheel is calculated based on the real-time steering angle of the steering wheel after filtering and the reference steering angle. The reference steering angular velocity of the steering wheel is calculated based on the steering angle error and the preset steering angle quantization error boundary; The reference magnetic thrust of the magnetic lead screw is calculated based on the filtered real-time steering angular velocity and the reference steering angular velocity of the steering wheel. The reference speed of the drive motor is calculated based on the real-time magnetic thrust of the magnetic lead screw after filtering and the reference magnetic thrust of the magnetic lead screw. The reference torque of the drive motor is calculated based on the real-time speed of the drive motor after filtering and the reference speed of the drive motor. The computing module is also used for: Obtain the preset quantization error boundary of the magnetic screw thrust and the real-time estimate of the lumped disturbance term of the magnetic screw thrust; The reference magnetic thrust of the magnetic lead screw is filtered to obtain the filtered reference magnetic thrust of the magnetic lead screw. Calculate the difference between the reference magnetic thrust of the magnetic screw after filtering and the real-time magnetic thrust of the magnetic screw after filtering, and use the difference as the magnetic thrust error of the magnetic screw. The reference speed of the drive motor is calculated based on the preset quantization error boundary of the magnetic screw thrust, the real-time estimate of the lumped disturbance term of the magnetic screw thrust, and the magnetic screw thrust error.

7. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the method as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1-5.

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