Air suspension dynamic test system

Abstract

The application provides an air suspension dynamic test system, comprising: a rack, the rack being provided with a lifting slide rail; a mounting frame, the mounting frame being slidingly fitted on the lifting slide rail; a suspension connecting tool; an excitation module, the excitation module comprising an exciter, the output end of the exciter being provided with an excitation table for placing a wheel; an inflation module, the inflation module comprising an air source, the air source being used for inflating or deflating an air spring; a first acceleration sensor, the first acceleration sensor being used for measuring the acceleration of the upper end of the air spring; a second acceleration sensor, the second acceleration sensor being used for measuring the acceleration of the lower end of the air spring; a third acceleration sensor, the third acceleration sensor being used for measuring the acceleration of the excitation table; and a stroke sensor, the stroke sensor being used for measuring the displacement of the air spring. The non-linear transfer characteristics of a single / dual chamber air suspension system without damper damping and the non-linear dynamic behavior of the single / dual chamber air suspension system can be determined.

Description

Technical Field

[0001] This invention relates to the field of automotive suspension technology, and more particularly to a dynamic testing system for air suspension. Background Technology

[0002] Air suspension generally refers to an air suspension system. Based on different road conditions and signals from distance sensors, the vehicle's computer can determine changes in vehicle height and then control the air compressor and exhaust valves to automatically compress or extend the springs, thereby lowering or raising the chassis ground clearance to increase high-speed vehicle stability or passability in complex road conditions.

[0003] In existing technologies, quarter-suspension test benches are typically used to simulate the operating conditions of air suspension systems. One existing quarter-suspension tire-coupled road simulation test bench includes a fixed base, a servo hydraulic actuator, a wheel tray, a spring mounting bracket, a control arm mounting bracket, a quarter-suspension, and a wheel. The servo hydraulic actuator, damper mounting bracket, and quarter-suspension are mounted on the base. During testing, the wheel is placed on the wheel tray, and the servo hydraulic actuator simulates the wheel's operating conditions on the road to assess the durability of the suspension system. However, this test bench can only apply force to the wheel and assess the durability of the suspension system through the servo hydraulic actuator; it cannot be used to determine the nonlinear transmission characteristics and nonlinear dynamic behavior of single / dual-chamber air suspension systems without dampers.

[0004] Therefore, there is an urgent need for an air suspension dynamic testing system that can solve the above problems. Summary of the Invention

[0005] This invention provides an air suspension dynamic testing system that can determine the nonlinear transmission characteristics and nonlinear dynamic behavior of single / dual-chamber air suspension systems without dampers.

[0006] This invention provides an air suspension dynamic testing system, comprising:

[0007] A platform, wherein a lifting slide rail is provided on the platform;

[0008] The mounting bracket is slidably mounted on the lifting slide rail;

[0009] A suspension connection fixture, comprising an upper wishbone fixture, a lower wishbone fixture, an unsprung fixture, and an oversprung fixture, wherein the upper wishbone fixture is used to connect to the upper wishbone and the mounting bracket respectively, the lower wishbone fixture is used to connect to the lower wishbone and the mounting bracket respectively, the unsprung fixture is used to connect to the lower end of the air spring and the lower wishbone, and the oversprung fixture is used to connect to the upper end of the air spring and the mounting bracket respectively;

[0010] The excitation module includes an exciter, and the output end of the exciter is provided with an excitation platform for placing the wheel;

[0011] The first acceleration sensor is used to measure the acceleration at the upper end of the air spring;

[0012] The second acceleration sensor is used to measure the acceleration at the lower end of the air spring;

[0013] A third accelerometer sensor is used to measure the acceleration of the excitation table;

[0014] A stroke sensor is used to measure the displacement of an air spring.

[0015] According to the air suspension dynamic testing system provided by the present invention, the output end of the exciter is provided with a mounting plate, the mounting plate is provided with an excitation slide rail, and the excitation table is slidably mounted on the excitation slide rail.

[0016] The air suspension dynamic testing system provided by the present invention further includes an inflation module, which includes an air source, an air pipe, a pressure sensor, and a pressure reducing valve. The air pipe is used to connect the air source and the air spring, and the pressure sensor and the pressure reducing valve are disposed on the air pipe.

[0017] According to the air suspension dynamic test system provided by the present invention, the upper fork arm tooling includes two upper fork arm connecting units. One end of the upper fork arm connecting unit is provided with an upper fork arm connecting assembly for connecting with the upper fork arm. The end of the upper fork arm connecting unit opposite to the upper fork arm connecting assembly is provided with a connecting plate for connecting with the mounting bracket.

[0018] The lower fork arm tooling includes two lower fork arm connecting units. One end of each lower fork arm connecting unit is provided with a first lower fork arm connecting component for connecting with the lower fork arm, and the other end of each lower fork arm connecting unit opposite to the first lower fork arm connecting component is provided with a second lower fork arm connecting component for connecting with the mounting bracket.

[0019] According to the air suspension dynamic test system provided by the present invention, the upper wishbone connection assembly includes an upper wishbone connection block, and the upper wishbone connection block is provided with a mounting hole for connecting to the end of the upper wishbone.

[0020] The first lower fork arm connection assembly includes a first lower fork arm connection block, which has a mounting hole for connecting to the end of the lower fork arm; the second lower fork arm connection assembly includes a second lower fork arm connection block, which has a connecting plate for connecting to the mounting bracket.

[0021] According to the air suspension dynamic testing system provided by the present invention, the sprung fixture includes a fixed seat and a fixed bracket. The fixed seat is disposed on the mounting frame, one end of the fixed bracket is connected to the upper end of the air spring, and the other end of the fixed bracket is connected to the fixed seat.

[0022] The unsprung tooling includes an unsprung connecting block, which has mounting holes for connecting the lower end of the air spring and the lower fork arm, respectively.

[0023] The air suspension dynamic testing system provided by the present invention also includes an angle gauge for measuring the air spring mounting angle.

[0024] The air suspension dynamic testing system provided by the present invention further includes a counterweight for adjusting the sprung mass of the air spring.

[0025] The air suspension dynamic testing system provided by the present invention also includes a base, and the test bench and the excitation module are both mounted on the base.

[0026] The air suspension dynamic testing system provided by the present invention further includes a hoisting mechanism for hoisting the test bench and the air suspension system.

[0027] The air suspension dynamic testing system provided by this invention uses a mounting frame on a test bench and a suspension connection fixture to connect the air suspension system and the mounting frame. During the test, a vibration exciter simulates the displacement of the road surface by the wheels. A first acceleration sensor, a second acceleration sensor, and a third acceleration sensor measure the acceleration of the upper end of the air spring, the lower end of the air spring, and the vibration table, respectively. A stroke sensor measures the displacement of the air spring. By processing the above measurement results, the nonlinear transmission characteristics and nonlinear dynamic behavior of the single / double chamber air suspension system without damper can be determined, providing support for the improvement and optimization of the air spring design parameters. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of an embodiment of the air suspension dynamic testing system provided by the present invention;

[0030] Figure 2 yes Figure 1 A magnified view of part A in the image;

[0031] Figure 3 This is a schematic diagram of an embodiment of the upper fork arm connection unit in the air suspension dynamic testing system provided by the present invention;

[0032] Figure 4 This is a schematic diagram of an embodiment of the lower fork arm connection unit in the air suspension dynamic test system provided by the present invention;

[0033] Figure 5 This is a schematic diagram of an embodiment of the unsprung tooling in the air suspension dynamic testing system provided by the present invention;

[0034] Figure 6 This is a schematic diagram of an embodiment of the sprung tooling in the air suspension dynamic testing system provided by the present invention;

[0035] Figure 7 This is one of the comparison charts of the sweep frequency characteristics test of a single-chamber air suspension;

[0036] Figure 8 This is the second comparison chart of the sweep frequency characteristics test of a single-chamber air suspension;

[0037] Figure 9 This is one of the comparison charts of the fixed-frequency characteristics test of a single-chamber air suspension;

[0038] Figure 10 This is the second comparison of the fixed-frequency characteristics test of a single-chamber air suspension.

[0039] Figure label:

[0040] 1. Platform; 2. Lifting slide rail; 3. Rail mounting base; 4. Mounting frame; 5. Vibrator; 6. Vibration table; 7. Mounting plate; 8. Vibration slide rail; 9. Angle gauge; 10. Counterweight; 11. Base; 12. Lifting mechanism; 13. Upper fork arm connecting unit; 131. Upper fork arm connecting block; 14. Lower fork arm connecting unit; 141. First lower fork arm connecting block; 142. Second lower fork arm connecting block; 15. Fixed seat; 16. Fixed bracket; 161. First connecting plate; 162. Second connecting plate; 17. Unsprung connecting block; 18. Upper fork arm; 19. Lower fork arm; 20. Air spring. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0042] The following is combined Figures 1-10This invention describes the dynamic testing system for air suspension provided by the present invention.

[0043] like Figure 1 The diagram shown is a schematic representation of an embodiment of the air suspension dynamic testing system provided by the present invention. The air suspension dynamic testing system of this embodiment includes:

[0044] A platform 1 is provided with a lifting slide rail 2. In this embodiment, the platform 1 is provided with a rail mounting seat 3, and the lifting slide rail 2 is installed on the rail mounting seat 3, with a total of two rails.

[0045] Mounting bracket 4 is slidably mounted on lifting slide rail 2. In this embodiment, mounting bracket 4 is frame-shaped and has two sliding sleeves on its inner side that are slidably engaged with the two lifting slide rails 2 respectively. Mounting bracket 4 is fitted over track mounting base 3 and the sliding sleeves are fitted onto the corresponding slide rails. In this way, mounting bracket 4 can move up and down along the slide rail. Mounting bracket 4 is also provided with T-slots and mounting holes to facilitate the installation and fixing of components in the system with mounting bracket 4.

[0046] Suspension connection fixtures, such as Figure 2 As shown, the suspension connection fixture includes an upper fork arm fixture, a lower fork arm fixture, a unsprung fixture, and a sprung fixture. The upper fork arm fixture is used to connect to the upper fork arm 18 and the mounting bracket 4, respectively. The lower fork arm fixture is used to connect to the lower fork arm 19 and the mounting bracket 4, respectively. The unsprung fixture is used to connect to the lower end of the air spring 20 and the lower fork arm 19, and the sprung fixture is used to connect to the upper end of the air spring 20 and the mounting bracket 4, respectively. By setting up the suspension connection fixture, the air suspension system can be connected to the test bench 1, which facilitates the measurement of various parameters of the air suspension system through the test bench 1 during testing.

[0047] The excitation module includes a vibrator 5, and the output end of the vibrator 5 is equipped with a vibration table 6 for placing the wheel. The function of the vibrator 5 is to simulate the displacement input of the road surface (such as sine, sweep frequency, random displacement excitation, etc.). During the test, the vibrator 5 is connected to the computer, and the output end of the vibrator 5 is controlled by the set program.

[0048] The first acceleration sensor is used to measure the acceleration at the upper end of the air spring 20;

[0049] The second acceleration sensor is used to measure the acceleration at the lower end of the air spring 20;

[0050] The third accelerometer is used to measure the acceleration of the excitation table 6;

[0051] The stroke sensor is used to measure the displacement of the air spring 20. In this embodiment, the stroke sensor is set on the mounting bracket 4 and is directly facing the air spring 20 during the test. Its principle is to output different voltages by measuring the angle, and then perform the measurement after geometric calibration.

[0052] like Figure 1 As shown, in this embodiment, the output end of the vibrator 5 is provided with a mounting plate 7, and the mounting plate 7 is provided with a vibration slide rail 8. The vibration table 6 is slidably mounted on the vibration slide rail 8. During the test, the wheel is placed on the vibration table 6. By setting the vibration table 6 on the vibration slide rail 8, the influence of lateral force on the vertical characteristics of the air suspension system can be eliminated during the test.

[0053] The air suspension dynamic testing system of this embodiment also includes an inflation module, which includes an air source, an air pipe, a pressure sensor, and a pressure reducing valve. The air source is used to inflate or deflate the air spring 20, and the air pipe connects the air source and the air spring 20. The pressure sensor and the pressure reducing valve are mounted on the air pipe. In this embodiment, the air source is a compressor, which generates high-pressure gas, which is connected to the air spring 20 through the air pipe. By installing a pressure sensor on the air pipe, the internal gas pressure of the air spring 20 can be recorded; by installing a pressure reducing valve on the air pipe, the internal gas pressure of the air spring 20 can be adjusted.

[0054] The air suspension dynamic testing system of this embodiment also includes an angle gauge 9 for measuring the installation angle of the air spring 20. This allows the measurement of the installation angle of the air spring 20, ensuring that the angle of the air spring 20 remains consistent with its position on the vehicle during testing, thereby reducing testing errors.

[0055] like Figure 1 As shown, the air suspension dynamic testing system of this embodiment also includes a counterweight 10 for adjusting the sprung mass of the air spring 20. In this embodiment, the counterweight 10 is fixed to the mounting frame 4 by bolts. During the test, different weights of counterweight 10 can be selected according to different test requirements to simulate different sprung masses.

[0056] like Figure 1 As shown, the air suspension dynamic testing system of this embodiment also includes a base 11, on which the test stand 1 and the vibration module are mounted. The base 11 facilitates the placement and fixation of the testing device and also facilitates the overall relocation of the system.

[0057] like Figure 1As shown, the air suspension dynamic testing system of this embodiment also includes a hoisting mechanism 12, which is used to hoist the test bench 1 and the air suspension system. When not conducting tests, the entire test bench 1 and the air suspension system can be hoisted using the upper hoisting mechanism 12 to protect the test bench 1 and the vibrator 5. The hoisting mechanism 12 also facilitates the transfer of the test bench 1 and the air suspension system.

[0058] The suspension connection fixture of this embodiment will be described in detail below. Please refer to the attached document. Figure 2 - Appendix Figure 6 .

[0059] The upper fork arm fixture includes two upper fork arm connecting units 13 (the front end of the upper fork arm 18 has two ends). One end of the upper fork arm connecting unit 13 is provided with an upper fork arm connecting assembly for connecting to the upper fork arm 18, and the other end of the upper fork arm connecting unit 13 opposite to the upper fork arm connecting assembly is provided with a connecting plate for connecting to the mounting bracket 4. During testing, the upper fork arm connecting assemblies of the two upper fork arm connecting units 13 can be connected to the ends of the upper fork arm 18 respectively, and the connecting plates of the two upper fork arm connecting units 13 can be connected to the mounting bracket 4.

[0060] Specifically, such as Figure 3 As shown, the upper fork arm connecting assembly includes an upper fork arm connecting block 131, connecting bolts, and connecting nuts. A connecting plate is disposed on the upper fork arm connecting block 131, which has mounting holes for connecting to the end of the upper fork arm 18. The upper fork arm connecting block 131 is connected to the end of the upper fork arm 18 via connecting bolts, connecting nuts, and mounting holes. In this embodiment, the upper fork arm connecting block 131 is a U-shaped block with a receiving groove for accommodating the end of the upper fork arm 18, and mounting holes are located at both ends of the receiving groove. During installation, the end of the upper fork arm 18 is inserted into the receiving groove, the connecting bolt passes through the two mounting holes and the through hole reserved at the end of the upper fork arm 18, and the end of the upper fork arm 18 is rotatably fitted onto the shank of the connecting bolt by the cooperation of the connecting nut and the connecting bolt. The connecting plate has through holes, which can be connected and fixed to the T-slot on the mounting bracket 4 by bolts / screws and other connecting parts.

[0061] The lower fork arm fixture includes two lower fork arm connecting units 14. One end of each lower fork arm connecting unit 14 is provided with a first lower fork arm connecting assembly for connecting to the lower fork arm 19, and the other end of each lower fork arm connecting unit 14 opposite to the first lower fork arm connecting assembly is provided with a second lower fork arm connecting assembly for connecting to the mounting bracket 4. During testing, the first lower fork arm connecting assemblies of the two lower fork arm connecting units 14 can be used to connect to the ends of the lower fork arms 19 respectively, and the second lower fork arm connecting assemblies of the two lower fork arm connecting units 14 can be used to connect to the mounting bracket 4.

[0062] Specifically, such as Figure 4As shown, the first lower fork arm connecting assembly includes a first lower fork arm connecting block 141, connecting bolts, and connecting nuts. The first lower fork arm connecting block 141 has mounting holes for connecting to the end of the lower fork arm 19. The first lower fork arm connecting block 141 is connected to the end of the lower fork arm 19 through connecting bolts, connecting nuts, and mounting holes. The second lower fork arm connecting assembly includes a second lower fork arm connecting block 142, on which a connecting plate for connecting to the mounting bracket 4 is connected. In this embodiment, the first lower fork arm connecting block 141 is also a U-shaped block, which has a receiving groove for accommodating the end of the lower fork arm 19, and mounting holes are provided at both ends of the receiving groove. During installation, the end of the lower fork arm 19 is inserted into the receiving groove. The connecting bolt passes through the two mounting holes and the through hole reserved at the end of the lower fork arm 19. The end of the lower fork arm 19 is rotatably fitted onto the shank of the connecting bolt by the cooperation of the connecting nut and the connecting bolt. The second lower fork arm connecting block 142 is also a U-shaped block with a through hole on its connecting plate. It can be connected and fixed to the T-slot on the mounting bracket 4 by bolts / screws or other connecting parts. In this embodiment, the first lower fork arm connecting block 141 and the second lower fork arm connecting block 142 are welded together. Of course, in some embodiments, the first lower fork arm connecting block 141 and the second lower fork arm connecting block 142 can also be connected by riveting or bolting. The first lower fork arm connecting block 141 and the second lower fork arm connecting block 142 can also be made as one piece.

[0063] like Figure 5 As shown, the spring fixture includes a fixed base 15 and a fixed bracket 16. The fixed base 15 is mounted on the mounting frame 4. One end of the fixed bracket 16 is connected to the upper end of the air spring 20, and the other end of the fixed bracket 16 is connected to the fixed base 15. Specifically, the fixed bracket 16 includes connecting bolts, connecting nuts, and a first connecting plate 161 and a second connecting plate 162 connected to each other. The first connecting plate 161 and the second connecting plate 162 are arranged opposite to each other. The first connecting plate 161 and the second connecting plate 162 are respectively provided with multiple mounting holes. The first connecting plate 161 is connected to the upper end of the air spring 20 through the through-hole connecting bolts, connecting nuts, and mounting holes. The second connecting plate 162 is connected to the fixed base 15 through the connecting bolts, connecting nuts, and mounting holes. The first connecting plate 161 and the second connecting plate 162 are circular, and multiple mounting holes (similar to flanges) are evenly distributed around their circumference. The first connecting plate 161 and the second connecting plate 162 are connected by multiple connecting posts to maintain the stability of their connection. During installation, align the first connecting plate 161 with the hole pre-drilled on the fixed base 15, and use connecting bolts and connecting nuts to connect and fix the connecting part of the first connecting plate 161 and the lower end of the fixed base 15; similarly, align the second connecting plate 162 with the hole pre-drilled on the upper end of the air spring 20, and use connecting bolts and connecting nuts to connect and fix the second connecting plate 162 and the top of the air spring 20.

[0064] like Figure 6 As shown, the unsprung tooling includes an unsprung connecting block 17, connecting bolts, and connecting nuts. The unsprung connecting block 17 has mounting holes for connecting the lower end of the air spring 20 and the lower fork arm 19, respectively. The unsprung connecting block 17 is connected to the lower end of the air spring 20 and the lower fork arm 19 through the connecting bolts, connecting nuts, and mounting holes. Specifically, the main body of the unsprung connecting block 17 is a hollow rectangular profile. The inner cavity of the profile is used to accommodate the lower end of the air spring 20, and its lower end is provided with a clearance groove for accommodating the lower fork arm 19. During installation, the lower end of the air spring 20 extends into the cavity of the lower spring connecting block 17. The connecting bolt passes through the corresponding mounting hole and the through hole reserved on the lower end of the air spring 20. The lower end of the air spring 20 and the lower spring connecting block 17 are connected by the cooperation of the connecting nut and the connecting bolt. The lower fork arm 19 is placed in the relief groove. The connecting bolt passes through the corresponding mounting hole and the through hole reserved on the lower fork arm 19. The lower fork arm 19 and the lower spring connecting block 17 are connected by the cooperation of the connecting nut and the connecting bolt.

[0065] In this way, the air spring 20 can be connected to the mounting bracket 4 through the upper fork arm fixture, the lower fork arm fixture, and the unsprung fixture.

[0066] The following is a detailed description of the test process of the air suspension dynamic test system in this embodiment.

[0067] First, a dynamic testing system for the air suspension was constructed. Experiments were conducted using a test bench and a Mechanical Test and Simulation (MTS) vibration system to verify the accuracy and correctness of the model and parameter identification theory proposed in this paper. Air springs were selected; only the stiffness and damping characteristics of the air springs themselves were considered during the test. Therefore, the damping characteristics generated by the shock absorber should be eliminated before the test. Specifically, the same tooling and piston rod structure as the single-chamber air spring shock absorber were designed, and the oil in the double-chamber air spring shock absorber was released, so that the shock absorber could only be used to guide and connect the suspension.

[0068] Test data was recorded using the MicroAutoBox II rapid control prototype. A vibration guide was used to release the lateral forces generated by the tires during the test. Considering the relationship between the angle sensor's output voltage and angle, and the geometric amplification relationship between the mounting screw and suspension travel, the calibration relationship between suspension travel and voltage can be obtained:

[0069] h AS =g2(g1(V) height ))=(-74.52V height +691.9)×10 -3

[0070] a = 10.424V acc -25.831

[0071] Among them, h AS The measured values ​​are the suspension dynamic travel values; g2 and g1 are the functions used in the calculation; V height V is the voltage of the altitude sensor. acc is the voltage of the accelerometer; 'a' is the calibrated acceleration value.

[0072] To determine the system's transfer function and verify the theory under different excitation amplitudes, sweep frequency, fixed frequency, and random excitation experiments were designed based on the capabilities of the excitation equipment. In the sweep frequency test, a constant amplitude frequency sweep was performed within the range of 0.001 Hz to 7 Hz, with a fixed amplitude A = 2.3 mm and a frequency slew rate of 0.5 octaves / second. Each amplitude underwent n = 10 tests. In the fixed frequency test, the excitation amplitude was set to A = 1 mm, 5 mm, and 10 mm. To accurately measure the system's transfer characteristics near the resonant region, the excitation frequency was set to f = 0.1 Hz, 0.5 Hz, 1 Hz, 1.3 Hz, 1.6 Hz, 2 Hz, 3 Hz, 4 Hz, and 5 Hz for each amplitude. Each experiment was performed n = 10 cycles, and the final steady-state response amplitude and phase were considered as the system's transfer characteristics. A narrowband white noise excitation displacement (S0 = 6.525 × 10⁻⁷ m) was designed. 2 Random excitations (5 rad / s < ω < 30 rad / s) were used to verify the system's dynamic response, and mean square spring position acceleration values ​​were used to describe the dynamic characteristics of driving on a normal rough road surface. The MicroAutoBox II sampled at a frequency of 1 kHz, and the recorded data was filtered before processing. In the frequency sweep test data processing, the transfer function of the system was calculated using an n-times frequency sweep test method.

[0073]

[0074] in, for arrive The transfer function; for and The cross-correlation function; for The autocorrelation function; The Fourier transform of the spring acceleration; Fourier transform (transpose) of the excitation input; Fourier transform of the excitation input.

[0075] The dynamic stiffness formula for an air spring can be expressed as:

[0076]

[0077]

[0078]

[0079] Where, k Re k Im These are the real and imaginary parts of the dynamic stiffness, where K(ω) is the total stiffness; k A γ is the effective area stiffness; k1 is the high-pressure gas stiffness; c1 is the equivalent damping of gas heat exchange; j is the imaginary unit; ω is the excitation frequency; γ is the specific heat ratio; p b0 This is the initial pressure; A eff V represents the effective area. b0 For effective volume; C V Specific heat capacity at constant volume; m b0 K represents the initial gas mass. b p is the heat exchange coefficient. b p represents the gas pressure during motion. atm denoted by σ0, represents the external atmospheric pressure; z represents the vertical displacement; K′ represents the real part of the dynamic stiffness of the rubber airbag, and K″ represents the imaginary part of the dynamic stiffness of the rubber airbag. The subscript 0 represents zero strain. ∞ Representing infinite strain, K′ m ′ represents the imaginary part of the maximum dynamic stiffness, A c The characteristic amplitude is denoted as .

[0080] Based on the dynamic stiffness formula, the equivalent model of a single-chamber air suspension can be equivalent to viscous damping, and its transmission characteristic expression can be further given:

[0081]

[0082] Δ U =k1 2 (k Δ 2 +(c1+c Δ ) 2 ω 2 )-2c1k1ω 2 (-c1k Δ +c1mω 2 +c Δ mω 2 )

[0083] +c1 2 ω 2 (k Δ 2 +c Δ 2 ω 2 -2k Δ mω 2 +m 2 ω 4 )

[0084] ΔB =2c1 2 k1ω 2 (k Δ -mω 2 )+c1 2 ω 2 (k Δ 2 +c Δ 2 ω 2 -2k Δ mω 2 +m 2 ω 4 )

[0085] +k1 2 (k Δ 2 -2k Δ mω 2 +ω 2 (c1 2 +2c1c Δ +c Δ 2 +m 2 ω 2 ))

[0086] Where Z2 is the Fourier transform of the spring position; Z q To excite the Fourier transform of the displacement;

[0087] Δ B Δ U The parameters introduced for ease of writing have no actual physical meaning; B, D, and the terms with subscripts 1 and 2 are parameters of the method of undetermined coefficients and have no actual physical meaning. m2 is the sprung mass; It is the spring acceleration; The unsprung velocity; is the spring velocity; k1 is the gas stiffness; c1 is the equivalent damping of heat exchange between the gas and the outside environment; The velocity is the intermediate coordinate; m t For tire quality; k is the unsprung acceleration. t For tire stiffness; z q To excite the amplitude; c t For tire damping; The road surface excitation velocity is represented by A; the excitation amplitude is represented by k. Δ z1 is the equivalent stiffness; z2 is the vertical displacement at the hub; z3 is the coordinate of the sprung mass; c Δ For equivalent viscous damping; z m z is the intermediate coordinate; q To stimulate amplitude.

[0088] Figures 7-10The dynamic stiffness variation trends under fixed-frequency excitation and swept-frequency excitation are shown respectively, and it can be seen that the agreement with the theoretical value is relatively high. In addition, the resonant frequency of the air spring system can shift by 0.29Hz (from 1.19Hz to 1.48Hz), indicating that the resonant frequency shift generated by the air suspension system is not negligible.

[0089] As can be seen from the above description of the embodiments, the air suspension dynamic testing system of this application has the following advantages:

[0090] Novel nonlinear transmission characteristics of undamped single / double-chamber air suspension systems were described by developing and constructing a quarter-chamber air suspension dynamic test system. These characteristics mainly include the frequency and amplitude dependence of the air spring struts, which should be considered when designing, matching, and modeling such systems. Corresponding sweep and fixed-frequency tests were conducted to improve and optimize the design parameters of the air springs.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An air suspension dynamic test system, characterized by, The utility model relates to a test bench for single / dual chamber air suspension system, comprising: a rack provided with lifting slide rails; a mounting frame slidingly fitted on the lifting slide rails; a suspension connecting tool comprising upper fork arm tools, lower fork arm tools, spring under tools and spring on tools, the upper fork arm tools being used for connecting with upper fork arms and the mounting frame respectively, the lower fork arm tools being used for connecting with lower fork arms and the mounting frame respectively, the spring under tools being used for connecting with lower ends of air springs and lower fork arms, and the spring on tools being used for connecting with upper ends of air springs and the mounting frame respectively; a vibration exciting module comprising a vibration exciter, the output end of the vibration exciter being provided with a vibration table for placing wheels; a first acceleration sensor for measuring the acceleration of the upper end of the air spring; a second acceleration sensor for measuring the acceleration of the lower end of the air spring; a third acceleration sensor for measuring the acceleration of the vibration table; a stroke sensor for measuring the displacement of the air spring; the nonlinear transfer characteristics of the single / dual chamber air suspension system without damper damping and the nonlinear dynamic behavior of the single / dual chamber air suspension system are determined by the acceleration of the upper end of the air spring, the acceleration of the lower end of the air spring, the acceleration of the vibration table and the displacement of the air spring, the damping characteristics generated by the damper are eliminated before the test, the same tool and piston rod structure as the damper of the single chamber air spring are set, and the oil in the damper of the dual chamber air spring is released, so that the damper can only be used for guiding and connecting the suspension.

2. The air suspension dynamic test system of claim 1, wherein, The output end of the vibration exciter is provided with a mounting plate, the mounting plate is provided with vibration exciting slide rails, and the vibration table is slidingly fitted on the vibration exciting slide rails.

3. The air suspension dynamic test system of claim 1, wherein, The utility model further comprises an inflation module, the inflation module comprising a gas source, an air pipe, a pressure sensor and a pressure reducing valve, the air pipe being used for connecting the gas source and the air spring, and the pressure sensor and the pressure reducing valve being arranged on the air pipe.

4. The air suspension dynamic test system of claim 1, wherein, The upper fork arm tool comprises two upper fork arm connecting units, one end of the upper fork arm connecting unit is provided with an upper fork arm connecting assembly for connecting with the upper fork arm, and the other end of the upper fork arm connecting unit opposite to the upper fork arm connecting assembly is provided with a connecting plate for connecting with the mounting frame; The lower fork arm tool comprises two lower fork arm connecting units, one end of the lower fork arm connecting unit is provided with a first lower fork arm connecting assembly for connecting with the lower fork arm, and the other end of the lower fork arm connecting unit opposite to the first lower fork arm connecting assembly is provided with a second lower fork arm connecting assembly for connecting with the mounting frame.

5. The air suspension dynamic test system of claim 4, wherein, The upper fork arm connecting assembly comprises an upper fork arm connecting block, the upper fork arm connecting block is provided with mounting holes for connecting with the end of the upper fork arm; The first lower fork arm connecting assembly comprises a first lower fork arm connecting block, the first lower fork arm connecting block is provided with mounting holes for connecting with the end of the lower fork arm; the second lower fork arm connecting assembly comprises a second lower fork arm connecting block, and the second lower fork arm connecting block is provided with a connecting plate for connecting with the mounting frame.

6. The air suspension dynamic test system of claim 1, wherein, The spring-on tool comprises a fixed seat arranged on the mounting frame and a fixed support, one end of which is connected with the upper end of the air spring, and the other end of which is connected with the fixed seat; The spring-under tool comprises a spring-under connecting block, on which mounting holes for connecting the lower end of the air spring and the lower fork arm are arranged.

7. The air suspension dynamic test system of any one of claims 1-6, wherein, An angle gauge for measuring the installation angle of the air spring is further included.

8. The air suspension dynamic test system of any one of claims 1-6, wherein, A counterweight for adjusting the spring-on mass of the air spring is further included.

9. The air suspension dynamic test system of any one of claims 1-6, wherein, A base is further included, on which the rack and the excitation module are arranged.

10. The air suspension dynamic test system of any one of claims 1-6, wherein, A hoisting mechanism for hoisting the rack and the air suspension system is further included.

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