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CN-121973583-A - Semi-active suspension damping control method for fusing excitation intensity between vehicle speed and road surface level

CN121973583ACN 121973583 ACN121973583 ACN 121973583ACN-121973583-A

Abstract

The invention relates to a semi-active suspension damping control method for fusing excitation intensity of vehicle speed and road surface grade, which comprises the following steps of 1, obtaining acceleration and displacement signals and vehicle speed signals of corresponding points, 2, obtaining road surface grade parameters reflecting the level of road surface unevenness, 3, comprehensively representing equivalent road surface vibration excitation intensity born by a suspension system under the current working condition, 4, determining the weight relation between a comfort index and a stability index in damping control, 5, enabling a target damping coefficient to be in a preset minimum damping and maximum damping range, and 6, realizing real-time adjustment of the damping of a shock absorber. The invention has the beneficial effects that 1, the damping adjustment can be adaptively adjusted along with the change of working conditions, 2, the problem of unbalanced performance of a single control target under complex working conditions is avoided, 3, the effective utilization rate of the vibration damper is improved, 4, the vibration damper is easy to directly realize on the existing semi-active vibration damper hardware platform, and 5, the vibration damper has good universality and engineering popularization value.

Inventors

  • Deng Mude
  • LIU FUYUN
  • SUN YONGHOU
  • JIANG XIAOLIANG
  • Wen Zeqian

Assignees

  • 桂林电子科技大学

Dates

Publication Date
20260505
Application Date
20260331

Claims (7)

  1. 1. The semi-active suspension damping control method for fusing the vehicle speed and the road surface level with the excitation intensity is characterized by comprising the following steps of: Step 1, acquiring an acceleration original signal and a vehicle speed signal through a signal sensing system, and defining suspension relative motion parameters through filtering and integration processing to obtain suspension system state parameters and vehicle speed signals; step 2, based on the suspension system state parameters obtained in the step 1, constructing road surface grade characteristic quantity after normalizing acceleration, obtaining relative road surface grade indexes through reference working condition alignment and mapping discrete road surface grades, and obtaining the road surface grade characteristic quantity, the relative road surface grade indexes and the discrete road surface unevenness grade parameters; Step 3, deriving the coupling excitation relation between the vehicle speed and the road surface grade based on the road surface grade parameter obtained in the step 2 and the vehicle speed signal obtained in the step 1, and constructing a fusion index in a multiplication mode after determining a weight index through simulation fitting to obtain a fusion excitation intensity index capable of comprehensively representing the equivalent vibration excitation intensity of the suspension; Step 4, constructing a suspension comprehensive performance index based on the fusion excitation intensity index obtained in the step 3, and combining a random vibration theory to analyze a risk rule of comfortableness and stability, and defining and deducing a dynamic weight function of the two to obtain a comfortableness and stability weight coefficient which adaptively changes along with the fusion excitation intensity; step 5, respectively deriving optimal damping under comfortable and stable targets based on the weight coefficient obtained in the step 4 and the suspension system state parameter obtained in the step 1, and obtaining a final target damping coefficient meeting the physical constraint of the semi-active suspension through physical constraint saturation treatment after fusion; And 6, deriving a target damping force based on the target damping coefficient obtained in the step 5 and combining the suspension relative speed in the step 1, converting the target damping force into a PWM driving signal after multi-loop optimization, and applying the PWM driving signal to the shock absorber to obtain a control current and the PWM driving signal which meet hardware constraint, thereby realizing real-time adjustment of the damping of the shock absorber.
  2. 2. The method for controlling the damping of a semi-active suspension by fusing the vehicle speed and the road surface level according to claim 1, wherein the step 1 is specifically: step 1.1, collecting signals, namely arranging acceleration sensors on the sprung mass and the unsprung mass of the suspension respectively, and collecting original signals of vertical acceleration of the sprung mass And vertical acceleration signal of unsprung mass Acquiring a vehicle speed signal through a controller local area network in the vehicle; Step 1.2, hardware RC low-pass filtering, namely removing irrelevant high-frequency components in an original acceleration signal, wherein the formula is as follows: ; wherein R, C are the resistance and capacitance values of the filter circuit respectively, which satisfy the following requirements , And For the hardware-filtered acceleration signal, Is the sampling period; step 1.3, mean filtering, namely further smoothing the hardware filtering signal, wherein the formula is as follows: ; ; Wherein, the For the current sampling instant of time, Is the sliding window length; step 1.4, calculating the speed and the displacement by trapezoidal integration, namely integrating the acceleration after mean value filtering to obtain the speed, and integrating the speed to obtain the displacement, wherein the formula is as follows: ; ; Wherein, the At the speed of the last moment in time, Is the displacement of the previous moment; step 1.5, defining relative motion parameters, namely defining relative speed and displacement variables of the suspension to be respectively And forming suspension system state parameters by combining the filtered acceleration, the filtered speed and the filtered displacement.
  3. 3. The method for controlling the damping of a semi-active suspension by fusing the vehicle speed and the road surface level according to claim 2, wherein the step 2 is specifically: and 2.1, normalizing the acceleration, namely eliminating the physical characteristics, the statistical characteristics and the magnitude order difference of the sprung mass acceleration and the unsprung mass acceleration, wherein the formula is as follows: ; ; Wherein, the Is the average value of acceleration; And 2.2, constructing road surface grade characteristic quantity, namely constructing by using the sprung mass acceleration, the unsprung mass acceleration and the like, introducing the characterization contribution of the weight coefficient balance and the unsprung mass acceleration to the road surface unevenness, wherein the formula is as follows: ; Wherein, the 、 Based on the statistical energy duty ratio, the following steps are obtained: , ; Is a time window; Step 2.3, determining a reference characteristic value, namely selecting a reference working condition to obtain a suspension response reference characteristic value as a road surface grade scale, wherein the formula is as follows: ; and 2.4, calculating a relative pavement grade index, namely representing the multiple relation of the current pavement excitation relative to the reference pavement excitation, wherein the formula is as follows: step 2.5 mapping discrete road surface grades by empirical threshold Mapping the relative road surface grade index into discrete road surface unevenness grade, wherein the formula is as follows:
  4. 4. the method for controlling the damping of a semi-active suspension by fusing the vehicle speed and the road surface level according to claim 3, wherein the step 3 is specifically: step 3.1, deducing the coupling excitation relation between the vehicle speed and the road surface, wherein the road surface displacement power spectral density is based on an ISO8608 road surface model In combination with time domain excitation Obtaining the time domain power spectral density: The response of the suspension system to road surface input is: wherein Defining system response energy for a suspension system transfer function By variable substitution Obtaining Demonstration of effective excitation intensity of suspension The road surface grade and the vehicle speed are determined together; Step 3.2, assuming an excitation intensity relation, namely combining engineering experience and a random road white noise model, and assuming that the relation between the excitation intensity and the road grade as well as the vehicle speed is: , wherein, Gain coefficients for excitation intensities at different points, As the road surface grade base number, For the vehicle speed of the vehicle, For the road surface weight index, Is a velocity weight index; Step 3.3, fitting the weight index and constructing a fusion index, namely determining by simulation fitting 、 Taking a value, constructing a fusion excitation intensity index in a multiplication mode, wherein the formula is as follows: 。
  5. 5. the method for controlling the damping of a semi-active suspension by fusing the vehicle speed and the road surface level according to claim 4, wherein the step 4 is specifically: And 4.1, constructing comprehensive performance indexes, namely, considering comfort and steering stability, and constructing the comprehensive performance indexes of a two-degree-of-freedom semi-active suspension system, wherein the formula is as follows: ; Wherein, the For riding comfort target, restrain sprung mass acceleration; = An operation stability target, restraining wheel runout; And 4.2, analyzing the relation between the risk and the fusion excitation intensity, wherein the stability failure probability is suspension response cross-boundary probability, and if the response is approximately Gaussian distribution: Then: And is also provided with Stability risk function Is exponentially variable, and comfort risk is approximately linearly related to fusion excitation intensity, i.e ; And 4.3, defining a stability weight function, namely taking the stability failure ratio as a stability weight, wherein the formula is as follows: Wherein, the Is a physical critical stimulus determined by the suspension travel limit and tire stiffness; and 4.4, deriving a comfort weight function, wherein the comfort weight is a complement of the stability weight, and the formula is as follows: 。
  6. 6. The method for controlling the damping of a semi-active suspension by fusing the vehicle speed and the road surface level according to claim 5, wherein the step5 is specifically: Step 5.1 deriving comfort optimum damping from the sprung mass dynamics formula Substituted into 、 = Obtaining: Solving an instantaneous extremum for the comfort performance cost function: And (3) solving to obtain: To avoid Causing singular, introducing smooth sign functions Sum of small positive numbers And (3) carrying out saturation treatment after correction, wherein the formula is as follows: wherein the saturation function is defined as: Wherein, the Is a small positive number, the number of which is, 、 Damping upper and lower limits respectively; Step 5.2, determining stability optimal damping, wherein the dynamic load of the tire is defined as a fluctuation part: The stability performance index may take the form of a variance: Deriving it to obtain The stability index is monotonic to the damping, and no internal minimum value exists, so the stability optimal damping is ; And 5.3, combining the weight coefficient to fuse the comfort and stability optimal damping to obtain an initial target damping coefficient, wherein the formula is as follows: Wherein, the 。
  7. 7. The method for controlling the damping of a semi-active suspension by fusing the vehicle speed and the road surface level according to claim 6, wherein the step 6 is specifically: And 6.1, deducing a target damping force, namely eliminating mathematical singular caused by a speed dead zone by combining linear damping definition with a smoothing factor, wherein the formula is as follows: Wherein, the As a result of the fact that the damping coefficient is the target, For the relative speed of the suspension frame, Is a smoothing factor; Step 6.2, obtaining initial control current by bilinear interpolation, namely obtaining different excitation speeds of the shock absorber by bench experiments in advance Different control currents Damping force F generated under, which is organized into a target current map indexed by speed and force The controller retrieves real time And Belonging grid intervals 、 Defining normalization factors , The initial target control current is obtained through bilinear interpolation, and the formula is as follows: ; Wherein, the A reference current value stored at a node within the table; and 6.3, limiting the current slope, namely avoiding shock of the shock absorber and damage of the electromagnetic coil caused by current abrupt change, wherein the formula is as follows: ; Wherein, the , For a preset maximum allowable current slope, In order to control the period of time, Actually outputting current for the last moment; and 6.4, hysteresis effect compensation, namely, eliminating hysteresis effect and static friction of the electromagnetic actuator by superposing high-frequency micro sinusoidal signals, wherein the formula is as follows: Wherein, the method comprises the steps of, For the signal amplitude value, Is the dithering frequency; And 6.5, converting PI closed loop feedback into a PWM signal, namely solving a basic duty ratio, wherein the formula is as follows: , Wherein, the For the resistance of the snubber coil, Is the equivalent resistance of the circuit, and the equivalent resistance of the circuit, The current deviation is generated by introducing PI closed loop compensation coil resistance temperature drift and current deviation into the real-time voltage of the vehicle-mounted power supply The final duty cycle formula is: ; Wherein, the Is a coefficient of proportionality and is used for the control of the power supply, As an integral coefficient of the power supply, Is the actual measured current; step 6.6, power consumption constraint, namely ensuring that the semi-active vibration damper only dissipates energy and does not generate energy, and judging the power consumption state If (if) then Then normally execute the calculated If (1) Forced setting And applying the final PWM driving signal to the semi-active shock absorber to realize real-time damping adjustment.

Description

Semi-active suspension damping control method for fusing excitation intensity between vehicle speed and road surface level Technical Field The invention relates to the technical field of vehicle suspension control, in particular to a semi-active suspension damping control method for fusing excitation intensity between vehicle speed and road surface level. Background The vehicle suspension system is an important part for connecting a vehicle body and wheels, and has the main functions of isolating vibration transmission of road surface unevenness to the vehicle body and improving the driving comfort, the steering stability and the driving safety of the vehicle. Along with the improvement of the running speed of the vehicle and the complicacy of road working conditions, the traditional passive suspension is difficult to simultaneously consider the requirements of the comfort and the stability of the vehicle under different vehicle speeds and different road conditions due to the fact that damping and rigidity parameters are fixed, and the requirements of modern vehicles on comprehensive performances are difficult to meet. The semi-active suspension realizes the self-adaptive adjustment of the vibration characteristics of the vehicle by adjusting the damping size of the shock absorber on the premise of not introducing energy additionally, has the advantages of low energy consumption, relatively simple structure, strong engineering realizability and the like, and is gradually widely researched and applied. At present, the semi-active suspension damping control method mainly comprises a Skyhook control method, a ground-canopy control method (Groundhook), a hybrid control method, a fuzzy control method, an optimal control method based on state feedback and the like, the existing majority of control methods mainly carry out damping adjustment based on instantaneous state quantities (such as sprung acceleration, suspension relative speed or displacement and the like) of a vehicle, the control strategy implicitly assumes that the running working condition of the vehicle is relatively fixed, and the influence of the running speed change of the vehicle on the excitation input characteristic of the road surface is not explicitly considered. In the actual running process, the frequency spectrum characteristic and the energy distribution of road surface excitation of the vehicle are obviously changed along with the change of the vehicle speed, and the requirements of the suspension system on damping adjustment are obviously different under the combined conditions of different road surface grades and different vehicle speeds. However, the existing semi-active suspension damping control method is mostly based on fixed control logic or single working condition assumption, and it is difficult to consider the coupling influence of the vehicle speed and the road surface level on the suspension performance requirement at the same time, so that the control effect is limited under part of working conditions. In the prior art, vehicle speed information and road surface information are usually processed respectively or participate in control decisions only in a discrete rule mode, and a fusion index capable of continuously and uniformly reflecting the running state of a vehicle and the excitation characteristics of an external road surface is not formed, so that the self-adaptive adjustment of semi-active suspension damping parameters is guided, and the response capability of a control strategy to complex working condition changes is limited. Under the conditions of complex roads and multiple vehicle speeds, if a fixed value or a simple switching mode is adopted for damping parameters, the performance compromise between the comfort and the operation stability of the suspension system is easily caused, and the full-working-condition optimal control is difficult to realize. The prior art does not provide an effective method for continuously adjusting damping parameters based on comprehensive working condition indexes, after vehicle speed information and road surface grade information are introduced to participate in semi-active suspension damping control, the system structure and control logic are more complex, and if systematic modeling and theoretical analysis are lacking, the problems of unstable control or sensitivity to parameter uncertainty and external disturbance are easily caused. Therefore, the invention provides a semi-active suspension damping control method based on a vehicle speed and road surface grade fusion index, which is based on vehicle running state and road surface excitation information and carries out self-adaptive adjustment on damping parameters of a semi-active suspension shock absorber by constructing the fusion index, thereby realizing dynamic optimization of suspension performance under different vehicle speeds and different road surface grades so as to improve comprehensive running performance of the veh