CN117944541A - Self-adaptive control method for stiffness of air spring of vehicle seat - Google Patents
Self-adaptive control method for stiffness of air spring of vehicle seat Download PDFInfo
- Publication number
- CN117944541A CN117944541A CN202410354380.2A CN202410354380A CN117944541A CN 117944541 A CN117944541 A CN 117944541A CN 202410354380 A CN202410354380 A CN 202410354380A CN 117944541 A CN117944541 A CN 117944541A
- Authority
- CN
- China
- Prior art keywords
- air
- air spring
- vehicle seat
- frequency
- suspension system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 239000000725 suspension Substances 0.000 claims abstract description 33
- 230000006835 compression Effects 0.000 claims abstract description 16
- 238000007906 compression Methods 0.000 claims abstract description 16
- 238000006073 displacement reaction Methods 0.000 claims description 20
- 238000013016 damping Methods 0.000 claims description 10
- 238000005070 sampling Methods 0.000 claims description 6
- 230000003044 adaptive effect Effects 0.000 claims description 5
- 230000005284 excitation Effects 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 2
- 238000002955 isolation Methods 0.000 abstract 1
- 230000001133 acceleration Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 208000008035 Back Pain Diseases 0.000 description 1
- 208000008930 Low Back Pain Diseases 0.000 description 1
- 206010041591 Spinal osteoarthritis Diseases 0.000 description 1
- 208000036319 cervical spondylosis Diseases 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 210000004197 pelvis Anatomy 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 208000005801 spondylosis Diseases 0.000 description 1
Abstract
The invention discloses a vehicle seat air spring stiffness self-adaptive control method, which comprises the following steps: and acquiring the mean square frequency of compression and extension of the air spring in the vehicle seat scissor type suspension system, and adjusting the air pressure of the air cavity of the air spring to enable the natural frequency of the vehicle seat scissor type suspension system to deviate from the mean square frequency. The invention can adjust the rigidity of the air spring, so that the natural frequency of the seat is far away from the excitation frequency of the road surface, the vibration isolation effect is achieved, and the riding comfort and the operability of the vehicle are improved.
Description
Technical Field
The invention relates to a control method for vehicle seat suspension, in particular to a self-adaptive control method for the stiffness of an air spring of a vehicle seat.
Background
Truck drivers and special vehicle operators are often subjected to vibrations in operation, which often result from road irregularities, with frequencies of vibrations typically between 0 and 20 Hz. The human body organ has a plurality of natural frequencies in the range, which can lead to the consequences of inattention, fatigue and reduced working efficiency of the operator. Since the natural frequencies of the pelvis, spine and heart are between 4 and 8Hz, vibrations in this band are the source of cervical spondylosis and lumbago for the driver of the truck, and most suspensions in conventional chairs amplify these low frequency vibrations.
Existing vehicle chassis suspensions are passive suspensions, and passive suspension seats amplify vibrations at frequencies near their natural resonant frequencies. The first natural frequency is typical and the passive suspension seat frequency with air springs and dampers is between 1 and 2 Hz. At low frequencies and high amplitudes of the excitation signal, the inefficient passive seating compromises driver health and shortens operating time.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a control method of a vehicle seat air spring stiffness self-adaptive control method, which solves the problem that the low-frequency vibration of a seat is transmitted to a human body to cause the vertical vibration of the human body to influence the health.
The technical scheme of the invention is as follows: a vehicle seat air spring rate adaptive control method comprising: and acquiring the mean square frequency of compression and extension of the air spring in the vehicle seat scissor type suspension system, and adjusting the air pressure of the air cavity of the air spring to enable the natural frequency of the vehicle seat scissor type suspension system to deviate from the mean square frequency.
Further, the air cavity of the air spring is connected with an additional air storage tank with variable volume, and the volume of the additional air storage tank is adjusted when the air pressure of the air cavity of the air spring is adjusted.
Further, the additional air storage tank is provided with a plurality of separation cavities, each separation cavity is connected with the air cavity of the air spring through a controllable valve, and the opening and closing of the controllable valve is controlled to adjust the volume of the additional air storage tank.
Further, the mean square frequency is determined by the following formula:
，/>，
wherein, MF is the mean square frequency, For displacement of compression or extension of the air spring, N is the difference/>, acquired during the sampling time TTotal number of/(ton)For air spring compression or extension displacement/>Frequency of time,/>For within sampling time TNumber of occurrences.
Further, when the air pressure of an additional air storage tank connected with the air cavity of the air spring is adjusted, a motion differential equation of a vibration model of the vehicle seat scissor type suspension system is established, and then a characteristic value is obtained by solving the motion differential equation and is used as the natural frequency of the vehicle seat scissor type suspension system, wherein the characteristic value is a function of the air pressure of the additional air storage tank.
Further, the characteristic value is a function of the air pressure of the air cavity of the air spring
,
Wherein,Is the characteristic value, C is the damping coefficient of a damper of a scissor type suspension system of the vehicle seat, M is the sum of the bearing mass of the seat and the mass of the upper end face of the seat,/>Is the air pressure of the air cavity of the air spring,/>Is the effective cross-sectional area of the air spring,Is the compression or tension displacement of the air spring.
Further, the natural frequency of the vehicle seat scissor suspension system is
,
Wherein,Is natural frequency, C is the damping coefficient of a damper of a scissor type suspension system of a vehicle seat, M is the sum of the seat bearing mass and the mass of the upper end face of the seat, and/(I)Is the air pressure of the air cavity of the air spring,/>Is the effective cross-sectional area of the air spring,/>Is the compression or stretching displacement of the air spring, controls the switch of the controllable valve to adjust the volume change/>, of the additional air storage tankMake/>And deviating from the mean square frequency by a maximum value.
Compared with the prior art, the invention has the advantages that:
The natural frequency of the vehicle seat scissor type suspension system is avoided from the mean square frequency by adjusting the air pressure of the air cavity of the air spring, and the mean square frequency represents the main vibration frequency of the road surface, so that resonance is avoided, and vertical vibration of the seat transmitted to a human body is weakened. The air pressure of the air cavity of the air spring can be indirectly and real-timely adjusted by adjusting the volume of the additional air storage tank, so that the seat system can adaptively follow the road surface impact. The use of the relative displacement to determine the natural frequency of the system helps to reflect small changes in road surface characteristics, including small depressions, bumps or other irregularities in the road surface, and in some cases, can reduce the effects of noise from the sensor measurements, with less sensitivity to noise than absolute displacement.
Drawings
FIG. 1 is a schematic view of a vehicle seat suspension system.
Fig. 2 is a schematic diagram of a position sensor.
Fig. 3 is a graph showing the relationship between the voltage signal collected by the displacement sensor and the distance (relative displacement) between the upper and lower end surfaces of the seat.
Fig. 4 is a pressure change diagram of the air chamber of the air spring.
Detailed Description
The invention is further illustrated, but is not limited, by the following examples.
Referring to fig. 1, a vehicle seat suspension system is installed between a seat 1 and a vehicle bottom 11, and includes the following components: the first hinge 2, the first cross arm 3, the second cross arm 4, the second hinge 6, the air spring 7, the fixing bolt 5, the electromagnetic valve assembly 8 (10 is an electromagnetic valve and is a part of the electromagnetic valve assembly 8), and the additional air storage tank 9 are divided into three closed chambers with unequal volumes, namely a third hinge 12, a first supporting arm 13, a fourth hinge 14, a damper assembly 15, a fifth hinge 19, a second supporting arm 18, a sixth hinge 17 and a seventh hinge 16. The concrete installation mode is as follows: the first cross arm 3 and the second cross arm 4 are arranged in a crossed mode, and the first cross arm 3 and the second cross arm 4 are connected through a fifth hinge 19. The fifth hinge 19 is movable up and down, left and right, and is rotatable. The upper end of the first cross arm 3 is connected with the bottom surface of the seat 1 through a first hinge 2, and the upper end of the second cross arm 4 is connected with the bottom surface of the seat 1 through a seventh hinge 16; the first hinge 2 is rotatable and non-slidable, and the seventh hinge 16 is slidable left and right and rotatable. The lower end of the first cross arm 3 is fixed to the vehicle bottom 11 through a fourth hinge 14, and the lower end of the second cross arm 4 is fixed to the vehicle bottom 11 through a second hinge 6. The fourth hinge 14 is slidable and rotatable left and right, and the second hinge 6 is non-slidable and rotatable. One end of the air spring 7 is fixedly connected to the vehicle bottom 10, and the other end of the air spring is connected to the second cross arm 4 through the fixing bolt 5; the air spring 7 is in air communication with an additional air tank 9 via a solenoid valve assembly 8. The damper assembly 15 is connected at one end to the third hinge 12 by a sixth hinge 17 and a second support arm 13. The sixth hinge 17 is slidable left and right, slidable up and down, and rotatable, and the third hinge 12 is slidable left and right, slidable up and down, and rotatable. Referring to fig. 2, the axle arm 20 of the displacement sensor contacts with the cross beam of the first cross arm 3, and when the first cross arm 3 rotates, the axle arm 20 of the displacement sensor is driven to rotate to generate different voltage signals for output, and the relation between the voltage signals collected by the displacement sensor and the distance between the upper end surface and the lower end surface of the seat is shown in fig. 3.
The vehicle seat air spring stiffness adaptive control method is as follows:
firstly, the mean square frequency of compression and extension of an air spring in a vehicle seat shear type suspension system is obtained.
The mean square frequency represents the center of vibration energy in the frequency spectrum to describe the main vibration component of random road surface excitation to human impact, and can be calculated by the following formula:
(1)
Wherein, For air spring compression or extension displacement/>Frequency of time,/>To/>, within the sampling time TNumber of occurrences.
(2)
Wherein, MF is the mean square frequency,For displacement of compression or extension of the air spring, N is the difference/>, acquired during the sampling time TIs a total number of (a) in the number of (a). At this time, MF represents the main vibration frequency of the road surface, and resonance is avoided by changing the inherent frequency conversion of the scissor suspension system of the vehicle seat to avoid frequencies near MF.
One way to change the inherent frequency conversion of a vehicle seat scissor suspension system is to adjust the air pressure of the air chamber of the air spring. The specific process comprises the following steps:
(one) establishing a motion differential equation of a vibration model of the vehicle seat scissor suspension system, and calculating by a formula (3):
(3)
Wherein the method comprises the steps of For the bearing quality,/>Is the quality of the upper end face of the seat,/>Is the vertical displacement of the upper end surface of the seat,/>Is the vertical speed of the upper end face of the seat,/>Is the vertical acceleration of the upper end face of the seat,/>For the vertical force generated by the air spring,/>For the damping force generated by the damper,/>Frictional force generated for the system,/>Force generated for end stops,/>The gravity is generated for bearing the mass and the mass of the upper end face of the seat.
Due to friction generated by the systemSince the force of the seat upper end surface striking the end stopper is negligible and is not considered, the expression (3) is rewritten as:
（4）
and (II) calculating the vertical force generated by the air spring.
Can be obtained by the formula (5):
（5）
The stiffness K of the air spring can be calculated by formula (6):
（6）
（7）
（8）
（9）
（10）
（11）
Is the compression or extension displacement of the air spring; /(I) Is the gas pressure in the air spring,/>Is the rate of change of the gas pressure in the air spring,/>Is of adiabatic coefficient,/>Is the internal temperature of the air spring,/>The wall surface temperature of the air spring is approximately the ambient temperature,/>Is the air spring surface area,/>Is the heat transfer coefficient of the wall surface of the air spring,/>Is the effective cross-sectional area of the air spring; the air spring is additionally provided with an undeformable air storage tank volume and an air spring volume/>Air flow rate at temperature T is/>，/>Is the volume change rate of the air spring, R is the gas constant,/>Initial air mass for the air spring; the air spring volume model is described as a cylindrical configuration, the diameter of the air spring is D, and the initial height is/>；/>For displacement of the lower end face of the seat,/>Is the compression ratio of the air spring.
And (III) calculating the damping force of the damper on the gravity.
Damping force generated by damperThe method can be obtained by the following formula:
(12)
(13)
Wherein, The damping rate of the damper; /(I)，/>，/>Is a polynomial coefficient; c is the damping coefficient of the damper,/>Is the speed of the lower end surface of the seat. Gravity/>And the bearing mass m and the seat upper end face mass/>G is proportional to the gravitational acceleration:
（14）
Fourth), determining the characteristic frequency of the shear type suspension system of the vehicle seat.
Formula (4) is rewritable:
（15）
For the acceleration of the lower end surface of the seat, let The above formula can be written as:
(16)
since this is a one degree of freedom system, the eigenvalues and eigenvectors are solved, assuming eigenvalues as Feature vector is/>The characteristic equation of the above formula is:
（17）
and (3) solving to obtain:
（18）
These characteristic values correspond to the natural frequency of the vehicle seat scissor suspension system. Because the damping coefficient C of the damper of the vehicle seat scissor type suspension system is a fixed value, the inherent mass M is basically unchanged, and therefore, the inherent frequency of the system is changed only by adjusting the stiffness of the air spring, so that the sensitive frequency band of a human body is avoided. Due to The size changes along with the pavement excitation change, and when the air spring structure is determined, the air spring structure is/>Approximately a fixed value, and therefore only by adjustment/>The size is used for changing the natural frequency of the system in real time.
And fifthly, adjusting the stiffness of the air spring in real time.
Additional air reservoir internal air pressure connected to air chamber of air springThe actual value of (2) is calculated by:
（19）
Wherein, Is the change rate of the air pressure in the air storage tank,/>To add the air temperature in the air storage tank,/>For adding the temperature of the wall surface of the gas storage tank,/>For the surface area of the additional gas tank,/>Is the total heat exchange coefficient of the additional gas tank.
The volume of the air storage tank can be adjusted in real time by utilizing the electromagnetic valve on the additional air storage tank(Totally three closed Chamber,/>)Total volume), the additional storage tank is divided into three parts, in fig. 1, the volume of the leftmost closed chamber is V, the volume of the middle closed chamber is 2V, the volume of the rightmost closed chamber is 3V), and the/>, can be changed by opening and closing the electromagnetic valve（V、2V、3V、4V、5V）。/>By changing the formula (19)The size also varies, and the/>, as shown by the formula (9)Can be adjusted in real time,/>As shown in fig. 4, and further effecting a change in the natural frequency of the scissor suspension system of the vehicle seat in accordance with equation (18). After the mean square frequency to be avoided is determined, the/> can be changed by the selection of the electromagnetic valveTo one of V, 2V, 3V, 4V, 5V to change/>Make the obtained/>The deviation from the mean square frequency is greatest, thereby optimizing the vibration of the seat.
Claims (7)
1. A vehicle seat air spring rate adaptive control method, comprising: and acquiring the mean square frequency of compression and extension of the air spring in the vehicle seat scissor type suspension system, and adjusting the air pressure of the air cavity of the air spring to enable the natural frequency of the vehicle seat scissor type suspension system to deviate from the mean square frequency.
2. The method for adaptively controlling the stiffness of an air spring of a vehicle seat according to claim 1, wherein an additional air tank of variable volume is connected to an air chamber of the air spring, and the volume of the additional air tank is adjusted when the air pressure of the air chamber of the air spring is adjusted.
3. The method for adaptively controlling the stiffness of an air spring of a vehicle seat according to claim 2, wherein the additional air tank is provided with a plurality of compartments, each of the compartments is connected with the air chamber of the air spring through a controllable valve, and the opening and closing of the controllable valve is controlled to adjust the volume of the additional air tank.
4. The vehicle seat air spring rate adaptive control method according to claim 1, wherein the mean square frequency is determined by the following formula:
，/>，
wherein, MF is the mean square frequency, For displacement of compression or extension of the air spring, N is the difference/>, acquired during the sampling time TTotal number of/(ton)For air spring compression or extension displacement/>Frequency of time,/>To/>, within the sampling time TNumber of occurrences.
5. The method according to claim 1, wherein when the air pressure of the additional air tank connected to the air chamber of the air spring is adjusted, a differential equation of motion of the vibration model of the vehicle seat scissor suspension system is established, and then the differential equation of motion is solved to obtain a characteristic value as a natural frequency of the vehicle seat scissor suspension system, the characteristic value being a function of the air pressure of the additional air tank.
6. The method for adaptively controlling stiffness of an air spring of a vehicle seat according to claim 5, wherein a function of an air pressure of an air chamber of said air spring is the characteristic value
,
Wherein,Is the characteristic value, C is the damping coefficient of a damper of a scissor type suspension system of the vehicle seat, M is the sum of the bearing mass of the seat and the mass of the upper end face of the seat,/>Is the air pressure of the air cavity of the air spring,/>Is the effective cross-sectional area of the air spring,/>Is the compression or tension displacement of the air spring.
7. The vehicle seat air spring rate adaptive control method of claim 3, wherein the natural frequency of the vehicle seat scissor suspension system is
,
Wherein,Is natural frequency, C is the damping coefficient of a damper of a scissor type suspension system of a vehicle seat, M is the sum of the seat bearing mass and the mass of the upper end face of the seat, and/(I)Is the air pressure of the air cavity of the air spring,/>Is the effective cross-sectional area of the air spring,/>Is the compression or extension displacement of the air spring, controls the switch of the controllable valve to adjust the volume change of the additional air storage tankMake/>And deviating from the mean square frequency by a maximum value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410354380.2A CN117944541A (en) | 2024-03-27 | 2024-03-27 | Self-adaptive control method for stiffness of air spring of vehicle seat |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410354380.2A CN117944541A (en) | 2024-03-27 | 2024-03-27 | Self-adaptive control method for stiffness of air spring of vehicle seat |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117944541A true CN117944541A (en) | 2024-04-30 |
Family
ID=90798234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410354380.2A Pending CN117944541A (en) | 2024-03-27 | 2024-03-27 | Self-adaptive control method for stiffness of air spring of vehicle seat |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117944541A (en) |
-
2024
- 2024-03-27 CN CN202410354380.2A patent/CN117944541A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9115781B2 (en) | Device for springing a mass, and method for adjusting and/or operating a fluid spring | |
| EP2236326B1 (en) | Active suspension and adaptive damping configuration | |
| US8844912B2 (en) | Shock absorber having compressible fluid | |
| US8342541B2 (en) | Apparatus and method for active spring suspension of a vehicle component | |
| US5682980A (en) | Active suspension system | |
| EP1446592B1 (en) | Seamless control of spring stiffness in a liquid spring system | |
| US6412759B1 (en) | Method for controlling system including a controllable air spring and a controllable shock absorber connected in parallel | |
| US10377202B2 (en) | Suspension device for vehicle | |
| EP2415621B1 (en) | Damping force control apparatus | |
| EP1659007B1 (en) | Air suspension and electronically controlled suspension system | |
| CN102678808A (en) | Shock absorbing system with combined rigidity and damping adjusting function and shock absorbing method | |
| JPH0437294B2 (en) | ||
| KR20120032783A (en) | Body amplitude sensitive air spring | |
| CN117944541A (en) | Self-adaptive control method for stiffness of air spring of vehicle seat | |
| US5054145A (en) | Cushion arrangement | |
| CN109747497B (en) | Self-adaptive control method for seat suspension | |
| Heo et al. | Modelling of continuously variable damper for design of semi-active suspension systems | |
| JPS61278639A (en) | Liquid-sealed type vibration insulating body | |
| JP2575485B2 (en) | Active suspension | |
| RU211255U1 (en) | Vehicle seat suspension | |
| RU215981U1 (en) | Vehicle seat suspension with active damping | |
| Galanti | Modelling, simulation and control for a skyhook suspension | |
| RU206649U1 (en) | Active vehicle seat suspension | |
| RU195215U1 (en) | Air suspension | |
| JPH08324220A (en) | Suspension device for vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |