Control method and system for magneto-rheological damper of electric two-wheeled vehicle, terminal equipment and computer readable storage medium

Abstract

The invention provides a control method and system for a magneto-rheological damper of an electric two-wheeled vehicle, terminal equipment and a computer readable storage medium, and belongs to the technical field of electric two-wheeled vehicle damper control. The method comprises the steps that the road surface state is recognized through frequency domain and time domain features of dynamic response of the electric two-wheeled vehicle; determining the real-time current of the magnetorheological damper based on the real-time motion signal and a road surface-vehicle body adjustment strategy; determining a target control strategy of the magnetorheological damper according to the road surface information; target damping force is determined according to the target control strategy and the vehicle motion information; and the magneto-rheological damper sends a target instruction signal, the target instruction signal is used for indicating the magnitude of current in the magneto-rheological damper, the magnitude change of the damping force of the magneto-rheological fluid is controlled through the magnitude change of the current, and the damping force is adjusted to the target damping force.

Description

Background Art

[0001] When a vehicle travels on the road, the suspension system experiences a certain degree of motion due to the excitation of the road surface. To ensure ride comfort, a shock absorber is placed between the vehicle body and the suspension system. These vibrations are dampened through the axial elastic deformation of the spring and the axial movement of the damper. Shock absorbers are categorized as active, passive, and semi-active. Passive shock absorbers lack adjustable parameters such as stiffness and damping, making them difficult to adapt to varying road conditions and usage. Active shock absorbers, while capable of adapting to road conditions to a certain degree, are complex, require high technical requirements, and are relatively expensive. Consequently, semi-active shock absorbers have been developed, offering relatively simple manufacturing processes, low cost, and excellent shock absorption.

[0002] Magnetorheological fluids (MRFs) are a rapidly developing class of smart materials. They are typically suspensions of micron- or nanometer-sized ferromagnetic particles (typically carbonyl iron particles) immersed in a non-magnetic carrier fluid, along with a small amount of other supporting solutions. Depending on the carrier fluid, they can be categorized as either magnetorheological fluids or magnetorheological greases. The volume fraction of ferromagnetic particles in magnetorheological materials typically ranges from 20% to 40%. Their rheological properties can be controlled by an applied magnetic field. Different magnetic field intensities produce varying performance, a characteristic known as the magnetorheological effect. Under the influence of an applied magnetic field, magnetorheological fluids exhibit non-Newtonian fluid behavior, transitioning from a free-flowing liquid to a semi-solid or even solid state within milliseconds, demonstrating highly controllable rheological properties. They behave as liquids in the absence of a magnetic field, but rapidly transform into a semi-solid state under an applied magnetic field, exhibiting significant shear hardening. This unique property holds great potential for broad application in diverse fields. Magnetorheological fluids (MRFs) react quickly, reversibly, and controllably to changes in the strength of an applied magnetic field. MR shock absorbers exploit this characteristic, using the magnetorheological effect and motion sensors on the vehicle body and wheels as input signals to respond in real time to road and operating conditions.

[0003] Existing designs typically adjust the damping coefficient of a magnetorheological damper by adding or removing holes in the piston. Once the piston structure is determined, the damping coefficient is typically fixed. Because road conditions vary during driving, the ideal damping coefficient required for each road surface varies. When matching magnetorheological dampers with vehicle suspensions, most designs are designed to only address specific operating conditions and fail to fully consider the impact of the shock absorber on vehicle ride comfort under varying road conditions, center of gravity distribution, and operating conditions.

[0004] Traditional magnetorheological damping control strategies rely on external sensors (such as radar) to obtain road surface information, which is costly and complex to install. Electric two-wheelers, due to their compact structure, require a higher level of sensor integration. Existing control methods based on real-time feedback struggle to infer road conditions from the vehicle's own dynamic response, resulting in significant lag. This makes it difficult to balance vehicle stability and comfort, especially on bumpy or winding roads. Summary of the Invention

[0005] The present invention provides a magnetorheological shock absorber control solution for electric two-wheeled vehicles based on a three-axis acceleration sensor. It identifies the road surface condition through the frequency domain and time domain characteristics of the vehicle's dynamic response, realizes real-time optimization and adjustment of the damping force, solves the problem of traditional solutions relying on external sensors, and improves the timeliness of control.

[0006] In a first aspect, an embodiment of the present application provides a method for controlling a magnetorheological shock absorber of an electric two-wheeled vehicle, comprising: Acquiring vehicle motion information, reflecting road conditions through the vehicle information, and adopting different control strategies for the magnetorheological shock absorber of the electric two-wheeled vehicle corresponding to different road conditions; determining a target control strategy for the magnetorheological shock absorber according to the road surface condition; determining a target damping force according to the target control strategy and the motion information; controlling the damping force of the magnetorheological shock absorber to be adjusted to the target damping force; The road surface condition includes frequency domain analysis of the Z-axis acceleration signal and fusion of the X / Y-axis acceleration standard deviation and peak count time domain features, including: In the frequency domain analysis, a fast Fourier transform (FFT) is performed on the Z-axis acceleration signal to extract the main frequency component and determine the road surface.

[0007] In the time domain feature fusion, the X / Y axis acceleration standard deviation and peak count are combined to identify the curve or slope state.

[0008] In a possible implementation of the first aspect, the motion information includes acceleration signals of an X-axis (front-back direction), a Y-axis (left-right direction), and a Z-axis (vertical direction); By using the frequency domain analysis, a fast Fourier transform is performed on the Z-axis acceleration signal to determine the road surface condition classification and determine the frequency control strategy; In a possible implementation of the first aspect, the Fourier transform data acquisition and preprocessing are implemented as follows: Sampling parameters: The three-axis accelerometer continuously samples Z-axis (vertical) acceleration signals at a sampling frequency of 200 Hz. The data is processed using a sliding window with a window length of 0.5 seconds (100 sampling points) and an overlap rate of 50% (i.e., the analysis results are updated every 0.25 seconds). Signal preprocessing: Detrending, removing the DC component of the acceleration signal (such as gravity acceleration); windowing function, using Hanning window to reduce spectrum leakage, satisfying the following formula: in is the window length; In a possible implementation manner of the first aspect, it is characterized in that the Fourier transform calculation and frequency domain feature extraction are implemented as follows: Z-axis acceleration data for each window Perform fast Fourier transform to get the spectrum : Divide the spectrum into low frequency band (0-5Hz), medium frequency band (5-20Hz), and high frequency band (20-100Hz), and calculate the energy proportion of each frequency band: in , the actual frequency needs to be adjusted according to the sampling rate.

[0009] In a possible implementation of the first aspect, it is characterized in that the road surface state classification logic is divided into a high-frequency enhancement strategy and a low-frequency suppression strategy: if (high-frequency energy accounts for more than 60%), it is determined to be a gravel road, triggering the high-frequency enhancement strategy; if And the time domain signal variance , it is determined to be a wavy road surface, triggering the low-frequency suppression strategy.

[0010] In a possible implementation of the first aspect, it is characterized in that the target damping force of the high-frequency damping enhancement strategy and the roll stabilization control strategy satisfies the following formula: High frequency damping enhancement strategy:

[0011] Maximum damping coefficient of magnetorheological shock absorber; The adjustment coefficient (value range 0.5-1.5) is dynamically adjusted according to the vehicle speed: ( is vehicle speed, unit is m / s); Shock absorber relative speed (vertical speed difference between vehicle body and wheel); Roll stability control strategy:

[0012] Weight dynamic adjustment rule: When the steering angle rate hour, ; When the steering angle rate .

[0013] In a second aspect, an embodiment of the present application provides a method for controlling a magnetorheological shock absorber for an electric two-wheeled vehicle, comprising a motion acquisition device, a road surface acquisition device, and a controller, wherein the motion acquisition device and the road surface acquisition device are both electrically connected to the controller, and the controller further communicates with the magnetorheological shock absorber; The road surface acquisition device is used to collect road surface information in front of the vehicle and to transmit the road surface information to the controller; the road surface information is used to reflect the road surface condition in front of the vehicle, and the control strategy of the magnetorheological shock absorber corresponding to different road surface conditions is different; The motion collection device is used to collect motion information of the vehicle and to transmit the motion information to the controller; The controller is configured to: obtain the motion information and the road surface information, determine a target control strategy for the magnetorheological shock absorber based on the road surface information, determine a target damping force based on the target control strategy and the motion information, and control the damping force of the magnetorheological shock absorber to be adjusted to the target damping force; In a third aspect, an embodiment of the present application provides a control system for a magnetorheological shock absorber of an electric two-wheeled vehicle, comprising: an acquisition module, configured to acquire vehicle motion information and road surface information in front of the vehicle, wherein the road surface information is used to reflect a road condition in front of the vehicle, and different control strategies of the magnetorheological shock absorber are corresponding to different road conditions; a strategy determination module, configured to determine a target control strategy for the magnetorheological shock absorber according to the road surface information; a target damping force determination module, configured to determine a target damping force according to the target control strategy and the motion information; a control module, configured to control the damping force of the magnetorheological shock absorber to be adjusted to the target damping force; In a fourth aspect, an embodiment of the present application provides a terminal device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the methods described in the first aspect when executing the computer program.

[0014] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and is characterized in that when the computer program is executed by a processor, it implements the method described in any one of the first aspects.

[0015] In a sixth aspect, an embodiment of the present application provides a computer program product, which, when executed on a terminal device, enables the terminal device to execute any of the methods described in the first aspect above.

[0016] Compared with the prior art, the embodiments of the present application have the following advantages: the present application identifies the road surface condition through the frequency domain and time domain characteristics of the dynamic response of the electric two-wheeled vehicle, determines the real-time current of the magnetorheological shock absorber based on the real-time motion signal and the road surface-body adjustment strategy; determines the target control strategy of the magnetorheological shock absorber based on the road surface information; determines the target damping force based on the target control strategy and the vehicle motion information; the magnetorheological shock absorber sends a target command signal, which is used to indicate the current in the magnetorheological shock absorber, and controls the damping force of the magnetorheological fluid by changing the current to adjust to the target damping force. The present application achieves accurate classification and prediction of road surface conditions through frequency domain-time domain fusion analysis of three-axis acceleration signals, without relying on external radar equipment, reducing costs and improving system reliability; and designs a dynamic weight optimization algorithm for curve and slope conditions to reduce vehicle body roll angle and vertical vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a schematic structural diagram of a method for controlling a magnetorheological shock absorber for an electric two-wheeled vehicle provided in one embodiment of the present application; Figure 2 1 is a flow chart of a method for controlling a magnetorheological shock absorber for an electric two-wheeled vehicle provided in one embodiment of the present application; Figure 3 1 is a schematic structural diagram of a control device for a magnetorheological shock absorber for an electric two-wheeled vehicle provided in one embodiment of the present application; Figure 4 It is a structural diagram of the terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] Figure 1 The structure diagram of the control system of the magnetorheological shock absorber for electric two-wheeled vehicle provided by one embodiment of the present application is presented. Figure 1 As shown, the control system of the magnetorheological shock absorber includes a motion acquisition device 2, a road surface acquisition device 1 and a controller 3. The motion acquisition device 2 and the road surface acquisition device 1 are both connected to the controller 3, and the controller 3 also communicates with the magnetorheological shock absorber 4.

[0019] The motion collection device 2 is used to collect the motion information of the vehicle and transmit the motion information of the vehicle to the controller 3. The motion collection device 2 is a sensor installed on the vehicle, which can collect motion information such as the vehicle's speed, acceleration, and vehicle posture.

[0020] The controller 3 is used to obtain motion information and road surface information, to determine a target control strategy for the vehicle based on the road surface information, to determine a target damping force based on the target control strategy and motion information, and to control the damping force of the magnetorheological shock absorber to be adjusted to the target damping force.

[0021] Figure 2 A flow chart of a method for controlling a magnetorheological shock absorber for an electric two-wheeled vehicle provided in one embodiment of the present application is shown.

[0022] See also Figure 2 As shown, the control method of the magnetorheological shock absorber includes steps S1 to S4. Steps S1 to S4 in the embodiment of the present application can be performed as follows Figure 1 The controller 3 shown is implemented.

[0023] Step S1, obtaining vehicle motion information and road surface information in front of the vehicle. The road surface information is used to reflect the road surface condition in front of the vehicle. Different control strategies of the magnetorheological shock absorber corresponding to different road surface conditions are different.

[0024] Specifically, motion information can be collected by a triaxial acceleration sensor mounted on the vehicle. This information includes information such as the vehicle's speed, acceleration, and posture. Road surface information can be collected by a collector. Road surface information reflects road surface conditions. The road surface collection device 1 can typically be mounted on the roof of a vehicle to collect road surface information ahead of the vehicle.

[0025] Step S2: determining a target control strategy for the magnetorheological shock absorber according to road surface information.

[0026] Specifically, the corresponding target control strategy is determined according to different road surface information to ensure that the appropriate target control strategy is used to control the magnetorheological semi-active suspension and improve the stability and accuracy of vehicle control.

[0027] Step S3: determining the target damping force according to the target control strategy and motion information.

[0028] Specifically, after the target control strategy is determined, the target damping force is determined according to the target control strategy and motion information.

[0029] Step S4: controlling the damping force of the magnetorheological shock absorber to be adjusted to a target damping force.

[0030] Specifically, when the target damping force is determined, the controller generates a corresponding current signal based on the target damping force. The current signal is loaded on the magnetorheological shock absorber, so that the damping force of the magnetorheological shock absorber is adjusted to the target damping force, thereby realizing adaptive adjustment of the magnetorheological shock absorber and improving the stability of vehicle driving.

[0031] In one embodiment of the present application, the signal preprocessing step includes: Detrending: Use linear fitting to remove the gravitational acceleration component. (length N=100), calculate the mean :

[0032] in , the processed signal is:

[0033] Windowing: Apply the Hanning window to reduce spectrum leakage. The window function is: Windowed signal:

[0034] In one embodiment of the present application, the frequency domain analysis and road surface condition classification satisfy the following formula: FFT calculation: Use the ARM CMSIS-DSP library to perform a 100-point FFT and output a complex spectrum : Frequency mapping: Actual frequency Frequency band energy calculation: Low frequency band (0-5 Hz): corresponding to :

[0035] High frequency band (20-100 Hz): corresponding to :

[0036] Total Energy:

[0037] Energy ratio:

[0038] Pavement classification rules.

[0039] Gravel road:

[0040] Wavy road surface:

[0041] Cornering conditions:

[0042] In one embodiment of the present application, the target damping force satisfies the following formula: High frequency damping enhancement strategy:

[0043] Maximum damping coefficient of magnetorheological shock absorber; The adjustment coefficient (value range 0.5-1.5) is dynamically adjusted according to the vehicle speed: Shock absorber relative speed (vertical speed difference between vehicle body and wheel).

[0044] Roll stability control strategy: Multi-objective optimization problem:

[0045] Weight adjustment:

[0046] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of this application. Their specific functions and technical effects can be found in the method embodiment section and will not be repeated here.

[0047] in addition, Figure 3 The control device of the magnetorheological shock absorber shown can be a software unit, a hardware unit, or a combination of software and hardware units built into an existing terminal device, or can be integrated into the terminal device as an independent pendant, or can exist as an independent terminal device.

[0048] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0049] Figure 4This is a schematic diagram of the structure of the terminal device provided in the embodiment of the present application. Figure 4 As shown, the terminal device 4 of this embodiment may include: at least one processor 5, a memory 6, and a computer program 7 stored in the memory 6 and executable on the at least one processor 5. When the processor 5 executes the computer program 7, the steps in any of the above method embodiments are implemented, for example Figure 2 Alternatively, when the processor 5 executes the computer program 7, the functions of the modules / units in the above-mentioned device embodiments are realized, for example Figure 3 Functions of modules 301 to 304 are shown.

[0050] In one embodiment of the present application, the control system hardware includes: 1.Embedded signal processor.

[0051] Main control chip: STM32H743, operating frequency 480 MHz, integrated FPU and DSP instruction set.

[0052] FFT acceleration: using the arm_cfft_q15 function of the CMSIS-DSP library, calculation time: 2. Magnetorheological actuator.

[0053] Drive circuit: Dual H-bridge design, supports PWM frequency of 20 kHz and maximum current of 5 A.

[0054] Current closed-loop control: PID parameters: , target current calculation: In one embodiment of the present application, the control device module implementation includes: 1. Signal preprocessing module.

[0055] Low-pass filtering: Second-order Butterworth filter, cutoff frequency 100 Hz, transfer function:

[0056] 2. Standardized processing.

[0057]

[0058] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0059] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0060] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A control method for a magnetorheological shock absorber of an electric two-wheeled vehicle, characterized in that: include: Acquiring vehicle motion information, reflecting road conditions through the vehicle information, and adopting different control strategies for the magnetorheological shock absorber of the electric two-wheeled vehicle corresponding to different road conditions; determining a target control strategy for the magnetorheological shock absorber according to the road surface condition; determining a target damping force according to the target control strategy and the motion information; controlling the damping force of the magnetorheological shock absorber to be adjusted to the target damping force; The road surface condition includes frequency domain analysis of the Z-axis acceleration signal and fusion of the X / Y-axis acceleration standard deviation and peak count time domain features, including: In the frequency domain analysis, a fast Fourier transform (FFT) is performed on the Z-axis acceleration signal to extract the main frequency component and determine the road surface; In the time domain feature fusion, the X / Y axis acceleration standard deviation and peak count are combined to identify the curve or slope state.

2. The control method of a magnetorheological shock absorber for an electric two-wheeled vehicle according to claim 1, characterized in that: The motion information includes acceleration signals of the X-axis (front-back direction), the Y-axis (left-right direction), and the Z-axis (vertical direction); By utilizing the frequency domain analysis and performing a fast Fourier transform on the Z-axis acceleration signal, the road surface state classification is determined and the frequency control strategy is determined.

3. The control method of a magnetorheological shock absorber for an electric two-wheeled vehicle according to claim 2, characterized in that: The Fourier transform data acquisition and preprocessing are implemented as follows: Sampling parameters: The triaxial accelerometer continuously samples Z-axis (vertical) acceleration signals at a sampling frequency of 200 Hz. Data is processed using a sliding window with a window length of 0.5 seconds (100 sampling points) and an overlap rate of 50% (i.e., analysis results are updated every 0.25 seconds). Signal preprocessing: Detrending, removing the DC component of the acceleration signal (such as gravity acceleration); windowing function, using Hanning window to reduce spectrum leakage, satisfying the following formula: in is the window length.

4. The control method of a magnetorheological shock absorber for an electric two-wheeled vehicle according to claim 3, characterized in that: The Fourier transform calculation and frequency domain feature extraction are implemented as follows: Z-axis acceleration data for each window Perform fast Fourier transform to get the spectrum : Divide the spectrum into low frequency band (0-5Hz), medium frequency band (5-20Hz), and high frequency band (20-100Hz), and calculate the energy proportion of each frequency band: The actual frequency needs to be adjusted according to the sampling rate.

5. The control method of a magnetorheological shock absorber for an electric two-wheeled vehicle according to claim 4, characterized in that: The road surface state classification logic is divided into high-frequency enhancement strategy and low-frequency suppression strategy: (high-frequency energy accounts for more than 60%), it is determined to be a gravel road, triggering the high-frequency enhancement strategy; if And the time domain signal variance , it is determined to be a wavy road surface, triggering the low-frequency suppression strategy.

6. The control method of a magnetorheological shock absorber for an electric two-wheeled vehicle according to claim 5, characterized in that: The target damping force of the high-frequency damping enhancement strategy and the roll stability control strategy satisfies the following formula: High frequency damping enhancement strategy: Maximum damping coefficient of magnetorheological shock absorber; The adjustment coefficient (value range 0.5-1.5) is dynamically adjusted according to the vehicle speed: Shock absorber relative speed (vertical speed difference between vehicle body and wheel) Roll stability control strategy: Weight dynamic adjustment rule: When the steering angle rate When the steering angle rate .

7. A control system for a magnetorheological shock absorber of an electric two-wheeled vehicle, characterized in that: It includes a motion collection device, a road surface collection device and a controller, wherein the motion collection device and the road surface collection device are both electrically connected to the controller, and the controller is also in communication with the magnetorheological shock absorber; The road surface acquisition device is used to collect road surface information in front of the vehicle and to transmit the road surface information to the controller; the road surface information is used to reflect the road surface condition in front of the vehicle, and the control strategy of the magnetorheological shock absorber corresponding to different road surface conditions is different; The motion collection device is used to collect motion information of the vehicle and to transmit the motion information to the controller; The controller is used to: obtain the motion information and the road surface information, determine a target control strategy for the magnetorheological shock absorber based on the road surface information, determine a target damping force based on the target control strategy and the motion information, and control the damping force of the magnetorheological shock absorber to be adjusted to the target damping force.

8. A control system for a magnetorheological shock absorber of an electric two-wheeled vehicle, characterized in that: include: an acquisition module, configured to acquire vehicle motion information and road surface information in front of the vehicle, wherein the road surface information is used to reflect a road condition in front of the vehicle, and different control strategies of the magnetorheological shock absorber are corresponding to different road conditions; a strategy determination module, configured to determine a target control strategy for the magnetorheological shock absorber according to the road surface information; a target damping force determination module, configured to determine a target damping force according to the target control strategy and the motion information; A control module is used to control the damping force of the magnetorheological shock absorber to be adjusted to the target damping force.

9. A terminal device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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