Variable parameter suspension control method, system, and electronic device

Abstract

The application provides a variable parameter suspension control method, system and electronic device, and belongs to the field of vehicle control. The method comprises the following steps: obtaining a road unevenness excitation; determining a filter cutoff frequency according to the road unevenness excitation; establishing a state equation of a suspension system; determining a frequency response function based on the road unevenness excitation and the state equation of the suspension system; and solving a control rate based on the road unevenness excitation, the filter cutoff frequency and the frequency response function, so as to control the force applied by a suspension beam on a vehicle mass borne by a wheel and the force applied by the suspension beam on a wheel mass. The application can balance the acceleration and dynamic travel under different road conditions.

Description

Technical Field

[0001] This invention relates to the field of vehicle control, and in particular to a variable parameter suspension control method, system, and electronic device. Background Technology

[0002] Acceleration and travel are two objectives of suspension control. Generally, the goal of control is to achieve both low acceleration and low travel, because low acceleration reduces vehicle bumps and improves comfort, while low travel reduces the probability of the suspension hitting the limit switch. However, theory shows that there is a contradictory relationship between acceleration and travel control; once the control parameters are determined, it is difficult to ensure a good balance between acceleration and travel under different road conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a variable parameter suspension control method, system, and electronic device that can achieve a balance between acceleration and dynamic travel under different road conditions.

[0004] To achieve the above objectives, the present invention provides a variable parameter suspension control method, comprising the following steps.

[0005] Obtain the road surface unevenness excitation.

[0006] The filter cutoff frequency is determined based on the road surface unevenness excitation.

[0007] Establish the state equations for the suspension system.

[0008] The frequency response function is determined based on the road surface roughness excitation and the state equation of the suspension system.

[0009] Based on the road surface roughness excitation, the filter cutoff frequency, and the frequency response function, the control law is solved to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass.

[0010] Optionally, the suspension system is a single-wheel suspension system.

[0011] Establishing the state equation of the suspension system includes: determining the differential equation of the single-wheel suspension system based on Newton's second law; and determining the state equation of the single-wheel suspension system based on the differential equation of the single-wheel suspension system.

[0012] Optionally, the differential equation of the single-wheel suspension system is: ; where m b m is the mass of the car carried by the wheels. w For the mass of the wheel, For the acceleration of the sprung mass, Let k be the acceleration of the unsprung mass.s x represents the stiffness of the suspension spring. b x represents the vertical displacement of the vehicle body. w Let be the vertical displacement of the wheel, and c be the vibration damping coefficient of the suspension. The velocity of the sprung mass Let k be the velocity of the unsprung mass. t Let be the elastic stiffness of the tire, q be the road surface roughness excitation, and u be the control rate. Indicates kinetic velocity. Indicates the suspension travel, (x) w -q) indicates the amount of tire deformation.

[0013] Optionally, the state equation of the single-wheel suspension system is: .

[0014] .

[0015] .

[0016] .

[0017] .

[0018] in, for The derivative of For state vectors, The state matrix, For the input matrix, Let T be the excitation matrix, and let T denote the transpose.

[0019] Optionally, the frequency response function includes a frequency response transfer function from road surface unevenness excitation to the wheel and a frequency response transfer function from road surface unevenness excitation to the vehicle body.

[0020] The frequency response transfer function from road surface unevenness excitation to the wheel is: .

[0021] The frequency response transfer function from the road surface unevenness excitation to the vehicle body is: .

[0022] in, Let be the frequency response transfer function from road surface roughness excitation to the wheel. Let j be the frequency response transfer function from road surface roughness excitation to vehicle body. Let x be the angular frequency. w x is the vertical displacement of the wheel. b Let q represent the vertical displacement of the vehicle body, and q represent the road surface unevenness excitation. Let be the natural frequency of the sprung mass. Let be the natural frequency of the unsprung mass. For the damping ratio, It is the mass ratio of the sprung mass to the unsprung mass.

[0023] Optionally, the formula is used. Solve for the control law.

[0024] Where u is the control rate, m b Let c1 and c2 be the mass of the car carried by the wheels, c1 and c2 be positive constants, and z1 be the first dummy controlled variable. , For the filtered response of the moving stroke, s is the Laplace operator. x is the filter cutoff frequency. b x represents the vertical displacement of the vehicle body. w Let z1 be the vertical displacement of the wheel, and z2 be the second virtual controlled variable. , The velocity of the sprung mass Let k be the velocity of the unsprung mass. s denoted as σ, where σ is the stiffness of the suspension spring, and c is the vibration damping coefficient of the suspension.

[0025] To achieve the above objectives, the present invention also provides a variable parameter suspension control system, comprising the following five modules.

[0026] The road surface excitation acquisition module is used to acquire road surface unevenness excitation.

[0027] The frequency determination module, connected to the road surface excitation acquisition module, is used to determine the filter cutoff frequency based on the road surface unevenness excitation.

[0028] The state equation establishment module is used to establish the state equations of the suspension system.

[0029] The response function determination module is connected to the road surface excitation acquisition module and the state equation establishment module, respectively, and is used to determine the frequency response function based on the road surface roughness excitation and the state equation of the suspension system.

[0030] The control module is connected to the road surface excitation acquisition module, the frequency determination module, the response function determination module, and the suspension beam of the suspension system, respectively. It is used to solve the control law based on the road surface roughness excitation, the filter cutoff frequency, and the frequency response function, so as to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass.

[0031] To achieve the above objectives, the present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to cause the electronic device to perform the above-described variable parameter suspension control method.

[0032] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention determines the filter cutoff frequency based on the road surface roughness excitation, sets different filter cutoff frequencies under different road surface conditions, and determines the frequency response function based on the road surface roughness excitation and the state equation of the suspension system. Based on the road surface roughness excitation, the filter cutoff frequency and the frequency response function, the control law is solved to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass, thereby achieving the balance of acceleration and dynamic travel of the suspension under different environments. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A flowchart of the variable parameter suspension control method provided by the present invention.

[0035] Figure 2 This is a schematic diagram of a single-wheel suspension system.

[0036] Figure 3 This is a schematic diagram of the variable parameter suspension control system provided by the present invention.

[0037] Symbol explanation: 1-Road excitation acquisition module, 2-Frequency determination module, 3-State equation establishment module, 4-Response function determination module, 5-Control module. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The purpose of this invention is to provide a variable parameter suspension control method, system, and electronic device, which achieves a balance between the acceleration and dynamic travel of the suspension under different environments by setting different control parameters (filter cutoff frequency) under different road conditions.

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Example 1: As Figure 1 As shown, this embodiment provides a suspension control method with variable parameters, including steps 100 to 500.

[0042] Step 100: Obtain road surface unevenness excitation.

[0043] Step 200: Determine the filter cutoff frequency based on the road surface unevenness excitation.

[0044] This invention selects different filter cutoff frequencies based on different road surface conditions to achieve a balance between acceleration and dynamic travel under varying road conditions. Specifically, when the dynamic travel is small, a smaller filter cutoff frequency is selected, indicating that high-frequency road disturbances that cause vibration acceleration response are suppressed. The high-frequency signal of the dynamic travel is equal to the vehicle body displacement, thus focusing the control emphasis on acceleration, which is equivalent to increasing the acceleration weighting value in the performance indicators. The smaller the filter cutoff frequency, the smaller the acceleration response of the system. At this time, the suspension becomes softer, and the dynamic travel will increase, making full use of the dynamic travel working space to reduce the impact of vibration acceleration. Conversely, when the dynamic travel is large, the control emphasis is placed on the low-frequency signal of the dynamic travel, which is equivalent to increasing the dynamic travel weighting coefficient in the performance indicators. At this time, the control feedback aims to prevent suspension breakdown, so the suspension becomes stiffer, and the suspension dynamic travel is effectively controlled, but at the cost of increased acceleration.

[0045] Step 300: Establish the state equations of the suspension system.

[0046] As one specific implementation method, the suspension system is a single-wheel suspension system, such as... Figure 2 As shown, this invention is based on the road surface unevenness excitation q(t) at time t and the vertical displacement x of the vehicle body at time t. b (t) and the vertical displacement x of the wheel at time t. w (t), determine the control law u(t) at time t.

[0047] Specifically, the differential equation of the single-wheel suspension system is first determined based on Newton's second law: .

[0048] Where, m bThe mass of the car carried by a single wheel, m w For the mass of the wheel, For the acceleration of the sprung mass, Let k be the acceleration of the unsprung mass. s x represents the stiffness of the suspension spring. b x represents the vertical displacement of the vehicle body. w Let be the vertical displacement of the wheel, and c be the vibration damping coefficient of the suspension. The velocity of the sprung mass Let k be the velocity of the unsprung mass. t Let be the elastic stiffness of the tire, q be the road surface roughness excitation, and u be the control rate. Indicates kinetic velocity. Indicates the suspension travel, (x) w -q) indicates the amount of tire deformation.

[0049] Then, based on the differential equation of the single-wheel suspension system, the state equation of the single-wheel suspension system is determined: .

[0050] .

[0051] .

[0052] .

[0053] .

[0054] in, for The derivative of For state vectors, The state matrix, For the input matrix, Let T be the excitation matrix, and let T denote the transpose.

[0055] Step 400: Determine the frequency response function based on the road surface roughness excitation and the state equation of the suspension system.

[0056] Specifically, the frequency response function includes a frequency response transfer function from road surface unevenness excitation to the wheel and a frequency response transfer function from road surface unevenness excitation to the vehicle body.

[0057] The frequency response transfer function from road surface unevenness excitation to the wheel is: .

[0058] The frequency response transfer function from the road surface unevenness excitation to the vehicle body is: .

[0059] in, Let be the frequency response transfer function from road surface roughness excitation to the wheel. Let j be the frequency response transfer function from road surface roughness excitation to vehicle body. Let x be the angular frequency. w x is the vertical displacement of the wheel. b Let q represent the vertical displacement of the vehicle body, and q represent the road surface unevenness excitation. Let be the natural frequency of the sprung mass. Let be the natural frequency of the unsprung mass. For the damping ratio, It is the mass ratio of the sprung mass to the unsprung mass. , , , .

[0060] Step 500: Based on the road surface roughness excitation, the filter cutoff frequency, and the frequency response function, solve for the control law to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass.

[0061] Specifically, the first dummy controlled variable is selected. ,in, For the filtered response of the moving stroke, , Let be the filter cutoff frequency, and s be the Laplace operator. For the first dummy controlled variable... Taking the first derivative, we get: .

[0062] Where, x1=x b , x3=x w .

[0063] To ensure the dynamic stability of the first virtual state variable z1, a second virtual controlled variable is selected. Where c1 is a positive constant.

[0064] The dynamic equation of the first virtual controlled variable z1 then becomes: .

[0065] Differentiating the second dummy controlled variable z2, we obtain the control law u: .

[0066] in, , .

[0067] As can be seen, the control law u is already present in the above equation, and the inverse solution yields: .

[0068] Where c2 is a positive constant.

[0069] This invention sets different filter cutoff frequencies under different road surface conditions to achieve a balance between the acceleration and dynamic travel of the suspension in different environments.

[0070] Example 2: In order to execute the method corresponding to Example 1 above and achieve the corresponding functions and technical effects, a variable parameter suspension control system is provided below.

[0071] like Figure 3 As shown, the variable parameter suspension control system provided in this embodiment includes: a road excitation acquisition module 1, a frequency determination module 2, a state equation establishment module 3, a response function determination module 4, and a control module 5.

[0072] The road surface excitation acquisition module 1 is used to acquire road surface unevenness excitation.

[0073] The frequency determination module 2 is connected to the road surface excitation acquisition module 1. The frequency determination module 2 is used to determine the filter cutoff frequency based on the road surface unevenness excitation.

[0074] The State Equation Establishment Module 3 is used to establish the state equations of the suspension system.

[0075] The response function determination module 4 is connected to the road surface excitation acquisition module 1 and the state equation establishment module 3 respectively. The response function determination module 4 is used to determine the frequency response function based on the road surface roughness excitation and the state equation of the suspension system.

[0076] The control module 5 is connected to the road surface excitation acquisition module 1, the frequency determination module 2, the response function determination module 4, and the suspension beam of the suspension system. The control module 5 is used to solve the control law based on the road surface roughness excitation, the filter cutoff frequency, and the frequency response function, so as to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass.

[0077] Compared to the prior art, the variable parameter suspension control system provided in this embodiment has the same beneficial effects as the variable parameter suspension control method provided in Embodiment 1, and will not be repeated here.

[0078] Example 3: This example provides an electronic device, including a memory and a processor. The memory is used to store a computer program, and the processor runs the computer program to make the electronic device perform the variable parameter suspension control method of Example 1.

[0079] Alternatively, the aforementioned electronic device may be a server.

[0080] In addition, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the variable parameter suspension control method of Embodiment 1.

[0081] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0082] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A suspension control method with variable parameters, characterized in that, The variable parameter suspension control method includes: Obtain the excitation of road surface unevenness; Based on the road surface unevenness excitation, the filter cutoff frequency is determined; specifically, different filter cutoff frequencies are selected according to different road surface conditions to achieve a balance between acceleration and dynamic stroke under different road surface conditions. Establish the state equation of the suspension system; the suspension system is a single-wheel suspension system; establishing the state equation of the suspension system includes: determining the differential equation of the single-wheel suspension system based on Newton's second law; and determining the state equation of the single-wheel suspension system based on the differential equation of the single-wheel suspension system. Based on the road surface roughness excitation and the state equation of the suspension system, a frequency response function is determined; the frequency response function includes a frequency response transfer function from the road surface roughness excitation to the wheel and a frequency response transfer function from the road surface roughness excitation to the vehicle body. Based on the road surface roughness excitation, the filter cutoff frequency, and the frequency response function, the control law is solved to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass. The control rate is calculated using the following formula: ； in, u For control rate, m b The mass of the car carried by its wheels. c 1 and c 2 is a positive constant. z 1 is the first dummy controlled variable. , For the filtered response of the moving stroke, , s For the Laplace operator, This is the filter cutoff frequency. x b This represents the vertical displacement of the vehicle body. x w This represents the vertical displacement of the wheel. z 2 is the second dummy controlled variable. , The velocity of the sprung mass The velocity of the unsprung mass, k s For the stiffness of the suspension springs, c This is the vibration damping coefficient of the suspension.

2. The variable parameter suspension control method according to claim 1, characterized in that, The differential equation for the single-wheel suspension system is: ； in, m b The mass of the car carried by its wheels. m w For the mass of the wheel, For the acceleration of the sprung mass, For unsprung mass acceleration, k s For the stiffness of the suspension springs, x b This represents the vertical displacement of the vehicle body. x w This represents the vertical displacement of the wheel. c This is the vibration damping coefficient of the suspension. The velocity of the sprung mass The velocity of the unsprung mass, k t This refers to the elastic stiffness of the tire. q For road surface unevenness excitation, u For control rate, Indicates kinetic velocity. Indicates the suspension travel, ( x w - q () indicates the amount of tire deformation.

3. The variable parameter suspension control method according to claim 2, characterized in that, The state equation of the single-wheel suspension system is: ； ； ； ； ； in, for The derivative of For state vectors, The state matrix, For the input matrix, For the activation matrix, T This indicates transpose.

4. The variable parameter suspension control method according to claim 1, characterized in that, The frequency response transfer function from road surface unevenness excitation to the wheel is: ； The frequency response transfer function from the road surface unevenness excitation to the vehicle body is: ； in, Let be the frequency response transfer function from road surface roughness excitation to the wheel. The frequency response transfer function from road surface roughness excitation to vehicle body. j It is an imaginary number. Angular frequency, x w This represents the vertical displacement of the wheel. x b This represents the vertical displacement of the vehicle body. q For road surface unevenness excitation, Let be the natural frequency of the sprung mass. Let be the natural frequency of the unsprung mass. For the damping ratio, It is the mass ratio of the sprung mass to the unsprung mass.

5. A variable parameter suspension control system, applied to the variable parameter suspension control method according to any one of claims 1-4, characterized in that, The variable parameter suspension control system includes: The road surface excitation acquisition module is used to acquire road surface unevenness excitation; The frequency determination module is connected to the road surface excitation acquisition module and is used to determine the filter cutoff frequency based on the road surface unevenness excitation. The state equation establishment module is used to establish the state equations of the suspension system; The response function determination module is connected to the road surface excitation acquisition module and the state equation establishment module, respectively, and is used to determine the frequency response function based on the road surface roughness excitation and the state equation of the suspension system. The control module is connected to the road surface excitation acquisition module, the frequency determination module, the response function determination module, and the suspension beam of the suspension system, respectively. It is used to solve the control law based on the road surface roughness excitation, the filter cutoff frequency, and the frequency response function, so as to control the force exerted by the suspension beam on the vehicle mass carried by the wheel and the force exerted by the suspension beam on the wheel mass.

6. An electronic device, characterized in that, The device includes a memory and a processor, the memory being used to store a computer program, and the processor running the computer program to cause the electronic device to perform the suspension control method with variable parameters as described in any one of claims 1 to 5.

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