阅读说明：本技术 一种基于频域分析的减振器控制方法及系统 (Vibration absorber control method and system based on frequency domain analysis ) 是由 宋慧新 金昊龙 肖洁 于 2021-07-16 设计创作，主要内容包括：本发明公开了一种基于频域分析的减振器控制方法及系统,采集悬架系统的悬架位移,将悬架位移作为测量信号；对测量信号进行分频滤波,得到各频段量值；根据悬架系统中减振器在每个频段的特性,对每个频段的量值分配对应权重系数；根据各频段量值及对应的权重系数,加权求和,得到合成的阻尼系数；利用合成的阻尼系数,对减振器进行控制。本发明通过分配各频段的权重系数,决定各频段内减振器最优控制时阻尼系数,从而生成最优的阻尼力,利于提高减振性能,同时节省减振功可以配置悬挂最优的阻尼力,解决流体减振时低频时因开阀造成的减振力不足和流体减振在高频小振幅振动下浪费驱动功率、恶化平顺性的问题；采用模拟电路滤波器,以减小时滞。(The invention discloses a vibration absorber control method and a vibration absorber control system based on frequency domain analysis, wherein the suspension displacement of a suspension system is collected and is used as a measurement signal; carrying out frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band; according to the characteristics of a shock absorber in a suspension system in each frequency band, a corresponding weight coefficient is distributed to the magnitude value of each frequency band; weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient; and controlling the shock absorber by utilizing the synthesized damping coefficient. According to the invention, by distributing the weight coefficients of each frequency band, the damping coefficient of the shock absorber in each frequency band during optimal control is determined, so that the optimal damping force is generated, the shock absorption performance is improved, the shock absorption work is saved, the optimal damping force can be configured, and the problems of insufficient shock absorption force caused by opening a valve during low frequency of fluid shock absorption and the problems of driving power waste and smoothness deterioration of the fluid shock absorption under high-frequency small-amplitude vibration are solved; an analog circuit filter is used to reduce skew.)

1. A shock absorber control method based on frequency domain analysis is characterized by comprising the following specific steps:

the method comprises the steps of collecting suspension displacement of a suspension system, and using the suspension displacement as a measurement signal;

performing frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band;

according to the characteristics of the shock absorber in each frequency band in the suspension system, a corresponding weight coefficient is distributed to the magnitude value of each frequency band;

weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient;

and controlling the shock absorber by utilizing the synthesized damping coefficient.

2. The method of claim 1, wherein the frequency-division filtering of the measurement signal is performed by:

acquiring two resonance main frequency points of the suspension system, and recording the two resonance main frequency points as a low main frequency point f according to the sizes_sHigh main frequency point f_u(ii) a Taking the turning frequency point f at the right side of the low dominant frequency point_syTurning frequency point f on left side of high dominant frequency point_uzHigh dominant frequency right turning frequency point f_uy；

f_sy、f_uzAnd f_uyThe three points divide the frequency band of the measurement signal into four sections, and the four sections are respectively marked as a low main frequency section, a middle frequency section, a high main frequency section and a high frequency section according to the frequency from low to high;

and filtering to obtain the magnitude value of each frequency band.

3. The method of claim 2, wherein the obtaining of the magnitude of each frequency band comprises:

the known total amplitude M of each frequency band is M_sy+M_uz+M_u+M_uyWherein M is_syIs low amplitude of main frequency band, M_uzFor mid-band amplitude, M_uIs a high main frequency amplitude, M_uyIs a high frequency band amplitude;

low dominant frequency range magnitude

Magnitude of intermediate frequency band

High dominant frequency range magnitude

High frequency range magnitude

4. The method of claim 3, wherein the assigning the weighting factors is performed by:

s_syis a low dominant frequency range magnitude weight coefficient, s_uzIs a medium frequency range magnitude weight coefficient, s_uIs a high dominant frequency range magnitude weight coefficient, s_uyIs a high-frequency range magnitude weight coefficient, and f is an input vibration frequency;

taking a certain damping ratio xi or a reference damping coefficient C as a reference, and when the maximum damping of the shock absorber is 3C;

when f is less than or equal to f_syThe reference damping coefficient C takes the maximum value, s, within the capacity of the shock absorber_sy＝3C；

When f is_sy≤f≤f_uzWhen it comes to s_uz＝0；

When f is_uz≤f≤f_uyAt this time, the reference damping coefficient C takes the maximum value, s_u＝1.5C；

When f is_uyWhen f is less, take s_uy＝0。

5. The method of claim 4, wherein the calculating the resultant damping coefficient is by:

known as c_s＝s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy；

Substitution of parameter s_sy、s_uz、s_u、s_uy、Δf_sy、Δf_uz、Δf_uAnd Δ f_uyThe value of (c) yields: c. C_s＝3CΔf_sy+1.5CΔf_u；

When s is_uz＝0，s_uyWhen equal to 0, c_s＝s_syΔf_sy+s_uΔf_u。

6. The method of claim 5 wherein the damping force of the shock absorber comprises a tensile damping force and a compressive damping force, and the damping coefficient comprises a tensile damping coefficient and a compressive damping coefficient;

let tensile damping system c_slAnd compression damping coefficient c_syThe ratio of the two is mu_cI.e. by

c_sy＝(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)；

c_sl＝μ_c(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)；

When s is_uz＝0，s_uyWhen the value is 0:

c_sy＝(s_syΔf_sy+s_uΔf_u)；c_sl＝μ_c(s_syΔf_sy+s_uΔf_u)；

when f is_sy≤f≤f_uzThe damping coefficient is 0, and the damping force is 0.

7. A frequency domain analysis based shock absorber control system, comprising: the device comprises a random vibration signal collector, a filter module and a damping coefficient synthesis module, wherein the random vibration signal collector is used for controlling damping force of a suspension system shock absorber;

the random vibration signal collector is used for collecting the suspension displacement of a suspension system and taking the suspension displacement as a measurement signal;

the filter module is used for carrying out frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band;

the damping coefficient synthesis module is used for distributing corresponding weight coefficients to the magnitude values of each frequency band according to the characteristics of the shock absorber in each frequency band in the suspension system; weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient;

the damping coefficient is output to the shock absorber.

8. The system of claim 7, wherein the filter module comprises a low pass filter, a low frequency band pass filter, an intermediate frequency band pass filter, and a high pass filter;

collecting low main frequency range amplitude M in the measurement signal by adopting a low-pass filter_sySetting the cut-off frequency of the low-pass filter to the measurement signal to f_sy+ Δ f; wherein f is_syThe turning frequency point on the right side of the low dominant frequency is provided, and delta f is more than or equal to 0;

collecting the mid-frequency range amplitude M in the measurement signal by using a low-frequency filter_uzLower cut-off frequency of f_syΔ f, upper cut-off frequency f_uz+ Δ f; wherein f is_uzThe left turning frequency point of the high dominant frequency;

collecting high main frequency range amplitude M in the measurement signal by adopting an intermediate frequency filter_uLower cut-off frequency of f_uzΔ f, upper cut-off frequency f_uy+ Δ f; wherein f is_uyThe right turning frequency point of the high dominant frequency;

collecting high-frequency range amplitude M in the measurement signal by adopting a high-pass filter_uyLower cut-off frequency of f_uy-Δf。

9. The system of claim 7, wherein the filter is an analog circuit filter.

Technical Field

The invention relates to the technical field of vehicle suspension vibration reduction, in particular to a vibration reducer control method and system based on frequency domain analysis.

Background

The traditional fluid vibration reduction adopts fluid such as oil, magnetorheological fluid, electrorheological fluid and the like, forms damping force on vibration through friction between a hole wall and the fluid and internal friction between fluid molecules, changes a liquid viscosity mode through throttling, and adjusts the magnitude of the damping force, wherein the damping force is determined by a damping coefficient and speed. The damping force generates heat energy and dissipates. The limitation is that the liquid is contacted with the vibrating structural part in real time, so that internal consumption is inevitably generated, and the liquid becomes a vibration increasing device under certain working conditions, so that the loss of the driving power of the vehicle is caused.

The calculation formula of the damping force of the traditional fluid shock absorber is as follows:

damping force F of fluid shock absorber_sSpeed v of relative movement only with suspension_sIn connection with, when the velocity v is_sNot more than valve opening speed v_kWhen the damping value is larger, it is c_d(ii) a When the valve is opened at a high relative speed, the damping value is c_x. In practical use, however, when low-frequency large-amplitude vibration is input, the vibration absorber is opened, so that the damping force on the vehicle body is insufficient; when high-frequency small-amplitude vibration is input, internal loss and driving power waste are caused due to large damping force, and the vibration absorber serves as a vibration increasing device to cause smoothness deterioration.

The traditional suspension shock absorber, such as a hydraulic shock absorber and an oil-gas suspension applied to a vehicle, and even representing a magneto-rheological suspension, an electro-rheological suspension and an adjustable orifice semi-active suspension, has an inherent characteristic, namely when the relative motion speed of the suspension is high, the damping force is reduced by opening a valve so as to meet the requirement of high-frequency shock absorption characteristics, but two results are brought, namely, high-frequency energy consumption cannot be removed; secondly, the low-frequency valve opening causes insufficient damping force; this drawback is due to the limitation of the damping principle.

On the other hand, the design of the damper is a comprehensive optimization result, rather than optimizing each frequency band. Based on the limitations, the conventional suspension only plays a role in vibration reduction at a low frequency band and a resonant frequency, but the suspension cannot realize vibration reduction at other frequency bands, but becomes a vibration increasing device, so that the vibration of a vehicle body is increased, and a large amount of driving power is consumed without load.

In recent years, electromagnetic vibration absorbers are researched and applied, the electromagnetic vibration absorbers generate damping force through a configuration mode of magnetoelectric conversion and dissipation resistance configuration, and a vibration-reduction optimal parameter control method is adopted to realize efficient vibration reduction and energy recovery of a suspension system, reduce the power consumption of the suspension system and improve the smoothness and the driving safety. The adjustment of the damping coefficient can be completed in millisecond level in the form of magnetoelectric vibration reduction, which is beneficial to quickly adapting to the load transfer of vehicles and adjusting the optimal damping force in real time; the adjusting range of the damping coefficient is large, and the damping force can be adjusted to be minimum at high frequency, so that the power consumption is saved; the working applicable temperature range is wide, and the damping characteristic is slightly influenced by the temperature, so that the performance of the fluid damping is not limited by the sealing working temperature.

In order to adapt to the technical development of the electromagnetic shock absorber, overcome the defects of the fluid shock absorber in the aspects of power consumption and damping force control, and improve the control effect of the shock absorber, a shock absorber control method and a shock absorber control system based on frequency domain analysis are urgently needed at present, the optimal damping force is adjusted in real time at a medium and low frequency, so that the shock absorber is favorably damped, the damping force can be adjusted to be minimum at a high frequency, and the technical effect of saving the power consumption is favorably achieved.

Disclosure of Invention

In view of this, the invention provides a method and a system for controlling a shock absorber based on frequency domain analysis, which can adjust the optimal damping force in real time at a medium and low frequency, thereby facilitating vibration reduction, and can adjust the damping force to the minimum at a high frequency, thereby facilitating power consumption saving.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a shock absorber control method based on frequency domain analysis specifically comprises the following steps:

and (4) collecting the suspension displacement of the suspension system, and taking the suspension displacement as a measurement signal.

And performing frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band.

According to the characteristics of the shock absorber in each frequency band in the suspension system, a corresponding weight coefficient is distributed to the magnitude of each frequency band.

And weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient.

And controlling the shock absorber by utilizing the synthesized damping coefficient.

Further, the frequency division filtering is performed on the measurement signal, and the specific method is as follows:

acquiring two resonance main frequency points of the suspension system, and recording the two resonance main frequency points as a low main frequency point f according to the sizes_sHigh main frequency point f_u(ii) a Taking the turning frequency point f at the right side of the low dominant frequency point_syTurning frequency point f on left side of high dominant frequency point_uzHigh dominant frequency right turning frequency point f_uy。

f_sy、f_uzAnd f_uyThe frequency band of the measurement signal is divided into four sections by the three points, and the four sections are respectively marked as a low main frequency band, a middle frequency band, a high main frequency band and a high frequency band according to the frequency from low to high.

And filtering to obtain the magnitude value of each frequency band.

Further, the method for obtaining the magnitude value of each frequency band comprises the following specific steps:

the known total amplitude M of each frequency band is M_sy+M_uz+M_u+M_uyWherein M is_syIs low amplitude of main frequency band, M_uzFor mid-band amplitude, M_uIs a high main frequency amplitude, M_uyIs the high band amplitude.

Low dominant frequency range magnitude

Magnitude of intermediate frequency band

High dominant frequency range magnitude

High frequency range magnitude

Further, a weight coefficient is assigned, and the specific method is as follows:

s_syis a low dominant frequency range magnitude weight coefficient, s_uzIs a medium frequency range magnitude weight coefficient, s_uIs a high dominant frequency range magnitude weight coefficient, s_uyIs the high-band magnitude weighting factor, and f is the input vibration frequency.

And taking a certain damping ratio xi or a reference damping coefficient C as a reference, and when the maximum damping of the shock absorber is 3C.

When f is less than or equal to f_syThe reference damping coefficient C takes the maximum value, s, within the capacity of the shock absorber_sy＝3C。

When f is_sy≤f≤f_uzWhen it comes to s_uz＝0。

When f is_uz≤f≤f_uyAt this time, the reference damping coefficient C takes the maximum value, s_u＝1.5C。

When f is_uy<When f is present, take s_uy＝0。

Further, the synthesized damping coefficient is calculated by the specific method:

known as c_s＝s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy。

Substitution of parameter s_sy、s_uz、s_u、s_uy、Δf_sy、Δf_uz、Δf_uAnd Δ f_uyThe value of (c) yields: c. C_s＝3CΔf_sy+1.5CΔf_u。

When s is_uz＝0，s_uyWhen equal to 0, c_s＝s_syΔf_sy+s_uΔf_u。

Further, the damping force of the shock absorber includes a tensile damping force and a compressive damping force, and the damping coefficient includes a tensile damping coefficient and a compressive damping coefficient.

Let tensile damping system c_slAnd compression damping coefficient c_syThe ratio of the two is mu_cI.e. by

c_sy＝(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)。

c_sl＝μ_c(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)。

When s is_uz＝0，s_uyWhen the value is 0:

c_sy＝(s_syΔf_sy+s_uΔf_u)；c_sl＝μ_c(s_syΔf_sy+s_uΔf_u)。

when f is_sy≤f≤f_uzThe damping coefficient is 0, and the damping force is 0.

A frequency domain analysis based shock absorber control system comprising: the device comprises a random vibration signal collector, a filter module and a damping coefficient synthesis module, and is used for controlling damping force of the suspension system shock absorber.

And the random vibration signal collector is used for collecting the suspension displacement of the suspension system and taking the suspension displacement as a measurement signal.

And the filter module is used for carrying out frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band.

The damping coefficient synthesis module is used for distributing corresponding weight coefficients to the magnitude values of each frequency band according to the characteristics of the shock absorber in each frequency band in the suspension system; and weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient.

The damping coefficient is output to the shock absorber.

Further, the filter module comprises a low-pass filter, a low-frequency band-pass filter, an intermediate-frequency band-pass filter and a high-pass filter.

Collecting low main frequency range amplitude M in the measurement signal by adopting a low-pass filter_sySetting the cut-off frequency of the low-pass filter to the measurement signal to be f_sy+. DELTA.f; wherein f is_syThe turning frequency point on the right side of the low main frequency, and delta f is more than or equal to 0.

Collecting the middle frequency range amplitude M in the measurement signal by using a low frequency filter_uzLower cut-off frequency of f_sy-. DELTA.f, upper cut-off frequency f_uz+. DELTA.f; wherein f is_uzThe left turning frequency point of the high dominant frequency.

Collecting high main frequency range amplitude M in the measurement signal by adopting an intermediate frequency filter_uLower cut-off frequency of f_uz-. DELTA.f, upper cut-off frequency f_uy+. DELTA.f; wherein f is_uyIs a turning frequency point on the right side of the high dominant frequency.

High-pass filter is adopted to collect high-frequency range amplitude M in measurement signal_uyLower cut-off frequency of f_uy－△f。

Further, the filter is an analog circuit filter.

Has the advantages that: according to the method, the weight coefficient of each frequency band is distributed according to different frequency band quantity values, the damping coefficient of the shock absorber in each frequency band during optimal control is determined, and the frequency domain analysis of the vibration signals is realized. According to the method, the damping coefficient is obtained through frequency domain analysis, the optimal damping coefficient of the shock absorber is obtained according to the magnitude values of different frequency bands, so that the optimal damping force is generated, the shock absorption performance is improved, the optimal damping force can be configured by saving the shock absorption work, and the problems that the shock absorption force is insufficient due to the valve opening during low frequency of fluid shock absorption and the driving power is wasted and the smoothness is deteriorated during high-frequency small-amplitude vibration of the fluid shock absorption are solved. Moreover, the system and the method can realize the real-time adjustment of the optimal damping force at medium and low frequency, thereby being beneficial to vibration reduction; the damping force can be minimized at high frequencies, which is beneficial for saving power consumption. Meanwhile, the system of the invention adopts an analog circuit filter to reduce time lag and avoid the defects of larger time lag of software filtering and unfavorable real-time control.

Drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is an amplitude-frequency characteristic diagram of suspension sprung mass acceleration versus road displacement input;

wherein, in fig. 1: ms is the mass of the vehicle body, also called sprung mass, Mu is the unsprung mass, also called unsprung mass, Ks is the stiffness of the suspension spring, Cs is the damping coefficient of the shock absorber, Ku is the stiffness of the tire, Cu is the damping coefficient of the tire, Zr is the vertical displacement of the road surface, Zu is the vertical displacement of the tire, and Zs is the vertical displacement of the vehicle body (or called sprung mass).

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

As shown in fig. 1, the present invention provides a method for controlling a shock absorber based on frequency domain analysis, which comprises the following steps:

the method comprises the steps of collecting suspension displacement of a suspension system, and taking the suspension displacement as a measurement signal; carrying out frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band; according to the characteristics of a shock absorber in a suspension system in each frequency band, a corresponding weight coefficient is distributed to the magnitude value of each frequency band; weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient; and controlling the shock absorber by utilizing the synthesized damping coefficient.

In the embodiment of the present invention, a specific method for performing frequency division filtering on a measurement signal is as follows:

acquiring two resonance main frequency points of the suspension system, and recording the two resonance main frequency points as a low main frequency point f according to the sizes_sHigh main frequency point f_u(ii) a Taking the turning frequency point f at the right side of the low dominant frequency point_syTurning frequency point f on left side of high dominant frequency point_uzHigh dominant frequency right turning frequency point f_uy. Wherein f is_sy、f_uzAnd f_uyThe three points divide the frequency band of the measurement signal into four sections, and the four sections are respectively marked as a low main frequency section, a middle frequency section, a high main frequency section and a high frequency section according to the frequency from low to high; and filtering to obtain the magnitude value of each frequency band.

In the embodiment of the invention, a specific method for obtaining the magnitude value of each frequency band comprises the following steps:

the known total amplitude M of each frequency band is M_sy+M_uz+M_u+M_uyWherein M is_syIs low amplitude of main frequency band, M_uzFor mid-band amplitude, M_uIs a high main frequency amplitude, M_uyIs the high band amplitude.

Wherein the low dominant frequency range magnitudeMagnitude of intermediate frequency bandHigh dominant frequency range magnitudeHigh frequency range magnitude

In the embodiment of the present invention, the specific method for assigning the weight coefficient is as follows:

known as_syIs a low dominant frequency range magnitude weight coefficient, s_uzIs a medium frequency range magnitude weight coefficient, s_uIs a high dominant frequency range magnitude weight coefficient, s_uyIs the high-band magnitude weighting factor, and f is the input vibration frequency.

With a certain damping ratio xi or a reference damping coefficient C as a reference, for example, with the damping ratio xi being 0.2, a reference damping coefficient can be obtained

When the maximum damping of the shock absorber is 3C:

when f is less than or equal to f_syThe reference damping coefficient C takes the maximum value, s, within the capacity of the shock absorber_syTaking the maximum damping value of the shock absorber, i.e. s_sy＝3C；

When f is_sy≤f≤f_uzIn time, the damping coefficient should be as small as possible, and s is taken_uz＝0；

When f is_uz≤f≤f_uyAt this time, the damping coefficient should be large, and if the damping coefficient is minimum, resonance at the resonance point is caused, and the vibration amplitude is large. At this time, the reference damping coefficient C is maximum and s is taken_u＝1.5C；

When f is_uy<When f is present, take s_uy＝0。

In the embodiment of the invention, the derivation principle of the calculated and synthesized damping coefficient is as follows:

the known damping force control formula for the shock absorber is: f_s(v_s)＝c_sv_s. Wherein, F_sFor damping force, v_sAs the frequency of vibration, c_sIs the resultant damping coefficient.

When s is_uz＝0，s_uyWhen 0, the formula can be further simplified as: f_s(v_s)＝c_sv_s。

In the formula: c. C_s＝s_syΔf_sy+s_uΔf_u。

When distinguishing the compression damping force from the tension damping force, let the tension damping coefficient c_slAnd compression damping coefficient c_syThe ratio of the two is mu_c，Then it can be obtained:

in the formula: c. C_sy＝(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)；

c_sl＝μ_c(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)。

When s is_uz＝0，s_uyWhen 0, the formula can be further simplified as:

in the formula: c. C_sy＝(s_syΔf_sy+s_uΔf_u)；

c_sl＝μ_c(s_syΔf_sy+s_uΔf_u)。

Therefore, the specific method of calculating the synthesized damping coefficient is:

damping force control formula, c_s＝s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy。

Substitution of parameter s_sy、s_uz、s_u、s_uy、Δf_sy、Δf_uz、Δf_uAnd Δ f_uyThe value of (c) can be given as: c. C_s＝3CΔf_sy+1.5CΔf_u。

When s is_uz＝0，s_uyWhen equal to 0, c_s＝s_syΔf_sy+s_uΔf_u。

In the embodiment of the invention, the damping force of the shock absorber comprises a tensile damping force and a compressive damping force, and the damping coefficient comprises a tensile damping coefficient and a compressive damping coefficient.

Tensile damping system c_slAnd compression damping coefficient c_syThe ratio of the two is mu_c，

Calculating a compression damping coefficient: c. C_sy＝(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)。

Calculating the tensile damping coefficient: c. C_sl＝μ_c(s_syΔf_sy+s_uzΔf_uz+s_uΔf_u+s_uyΔf_uy)。

When s is_uz＝0，s_uyWhen the value is 0: c. C_sy＝(s_syΔf_sy+s_uΔf_u)，c_sl＝μ_c(s_syΔf_sy+s_uΔf_u)；

When f is_sy≤f≤f_uzThe damping coefficient is 0, and the damping force is 0.

The invention provides a shock absorber control system based on frequency domain analysis, which comprises a random vibration signal collector, a filter module and a damping coefficient synthesis module and is used for controlling damping force of a shock absorber of a suspension system.

The system comprises a random vibration signal collector, a random vibration signal detector, a random vibration signal processing unit and a control unit, wherein the random vibration signal collector is used for collecting suspension displacement of a suspension system and taking the suspension displacement as a measurement signal; the filter module is used for carrying out frequency division filtering on the measurement signal to obtain the magnitude value of each frequency band; the damping coefficient synthesis module is used for distributing corresponding weight coefficients to the magnitude values of each frequency band according to the characteristics of the shock absorber in each frequency band in the suspension system; weighting and summing according to the magnitude value of each frequency band and the corresponding weight coefficient to obtain a synthesized damping coefficient; the damping coefficient is output to the shock absorber.

In the embodiment of the invention, the filter module comprises a low-pass filter, a low-frequency band-pass filter, an intermediate-frequency band-pass filter and a high-pass filter. The filter is an analog circuit filter.

Collecting low main frequency range amplitude M in the measurement signal by adopting a low-pass filter_sySetting the cut-off frequency of the low-pass filter to the measurement signal to f_sy+. DELTA.f; wherein f is_syThe turning frequency point on the right side of the low main frequency, and delta f is more than or equal to 0;

collecting the mid-frequency range amplitude M in the measurement signal by using a low-frequency filter_uzLower cut-off frequency of f_sy-. DELTA.f, upper cut-off frequency f_uz+. DELTA.f; wherein f is_uzThe left turning frequency point of the high dominant frequency;

collecting high main frequency range amplitude M in the measurement signal by adopting an intermediate frequency filter_uLower cut-off frequency of f_uz-. DELTA.f, upper cut-off frequency f_uy+. DELTA.f; wherein f is_uyThe right turning frequency point of the high dominant frequency;

collecting high-frequency range amplitude M in the measurement signal by adopting a high-pass filter_uyLower cut-off frequency of f_uy－△f。

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.