Pressure simulation method for pressure tube sensor of active pop-up hood

Abstract

This invention provides a pressure simulation method for a pressure tube sensor used in an active pop-up hood. The pressure tube sensor includes a pressure tube and two pressure sensors disposed at opposite ends of the pressure tube. The pressure simulation method includes: a first test step of conducting an impact test on the pressure tube; a first acquisition step of acquiring a first pressure curve representing the pressure at opposite ends of the pressure tube within a preset time period; a first modeling step of establishing a drop simulation model of the pressure tube sensor to obtain the first simulated pressure curve; and a first solution step of solving for the match between the first pressure curve and the first simulated pressure curve to obtain first simulation data, which includes a set of dimensional parameters, a set of material parameters, a set of performance response parameters, and a set of contact performance parameters. The technical solution of this invention solves the problem of low accuracy in simulation calibration of pressure tube sensor pressure simulation methods in the prior art, which easily leads to high costs in later vehicle development.

Description

Technical Field

[0001] The present invention relates to the technical field of active pop-up hoods, and in particular to a pressure simulation method for a pressure tube sensor of an active pop-up hood. Background Art

[0002] As the traffic accident and casualty rates of vulnerable road users (pedestrians and two-wheeled vehicle riders) increase, protection technologies for vulnerable road users are also widely used. The active pop-up hood system is a technology that is increasingly widely used to protect vulnerable road users. It detects the intensity and type of collision through a sensing system arranged at the front of the vehicle, and then transmits the sensing signal to the ECU for judgment. When the detonation threshold is reached (pedestrians are detected), an ignition signal is sent to the actuator; then, the actuator acts to lift the hood to the designated area to reduce the level of pedestrian head injury. The main pain point of the active pop-up hood system for passenger cars during application is false explosion, which is mainly reflected in the inability to accurately identify collisions with pedestrians and collisions with other non-pedestrian objects. Therefore, accurate identification of pedestrians and non-pedestrian objects has become the core problem of the active pop-up hood system. Compared with the traditional method of using only acceleration sensors, the current mainstream pressure tube sensor can better predict pedestrian collisions and reduce false explosions and is widely used.

[0003] Since the pressure tube is a plastic tube filled with gas at a certain pressure, it is difficult to accurately simulate the changing characteristics of the pressure signal through simulation. In addition, the distinguishing characteristics of the pressure tube sensor signal are closely related to the styling, layout and front-end structural design. Therefore, it is necessary to establish an accurate simulation method in the early stage of passenger car development, and it is especially necessary to achieve the optimal design before the styling, layout and front-end structure are finalized.

[0004] Existing simulation methods for pressure pipes include: first, based on material tensile testing, whose performance is difficult to accurately characterize the characteristics of pressure signals; second, simulation calibration through vehicle-level impact tests. Due to the introduction of the influence of exterior decoration and foam, the calibration results are often not ideal, resulting in low accuracy in signal prediction in the early stages of project development. In the actual vehicle verification stage of the project, design problems are exposed, resulting in high rectification costs and long rectification cycles. Summary of the invention

[0005] The main purpose of the present invention is to provide a pressure simulation method for a pressure tube sensor of an active pop-up hood, so as to solve the problem that the simulation calibration accuracy of the pressure simulation method of the pressure tube sensor in the prior art is low, which easily leads to high cost of subsequent vehicle development.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a pressure simulation method for a pressure tube sensor for an active pop-up hood, the pressure tube sensor comprising a pressure tube and two pressure sensors arranged at opposite ends of the pressure tube, the pressure simulation method comprising: a first test step of performing an impact test on the pressure tube; a first acquisition step of obtaining a first pressure curve of the pressures exerted on the opposite ends of the pressure tube within a preset time period; a first modeling step of establishing a drop simulation model of the pressure tube sensor to obtain a first simulation pressure curve; a first solution step of matching and solving the first pressure curve and the first simulation pressure curve to obtain first simulation data, wherein the first simulation data comprises a size parameter group, a material parameter group, a performance response parameter group and a contact performance parameter group.

[0007] Furthermore, the first test step includes using a drop impactor to drop the pressure tube from multiple preset heights and perform impact tests on the pressure tube respectively.

[0008] Furthermore, the preset height H i Satisfy the formula: Among them, M o is the equivalent mass that hits the human body or the mass of the standard impactor, V i is the relative speed of the impactor, M is the mass of the falling impactor, g is the acceleration of gravity, H i V i Corresponding different preset heights.

[0009] Furthermore, after the first acquisition step and before the first solution step, the pressure simulation method also includes a judgment step of whether the two first pressure curves obtained from the two ends of the pressure pipe are consistent. If yes, the first solution step is executed; if not, the first test step is executed.

[0010] Furthermore, the first modeling step includes: a first simulation step of inputting initial values ​​of a size parameter group of the pressure tube to simulate the shape of the pressure tube; a second simulation step of inputting initial values ​​of a performance response parameter group of the pressure tube to simulate the performance response capability of the pressure tube; a third simulation step of inputting initial values ​​of a material parameter group of the pressure tube to simulate the material of the pressure tube; and a fourth simulation step of inputting initial values ​​of a contact performance parameter group of the pressure tube to simulate the contact between the pressure tube and a drop impactor.

[0011] Further, the size parameter group includes at least one of the length dimension of the pressure pipe and the cross-sectional area dimension of the pressure pipe; or, the performance response parameter group includes at least one of the speed of sound, initial pressure, viscosity coefficient and damping coefficient; or, the material parameter group includes at least one of density, Young's modulus, Poisson's ratio, yield strength and tangent modulus; or, the contact performance parameter group includes at least one of the secondary surface penalty stiffness coefficient, primary surface penalty stiffness coefficient, static friction coefficient, dynamic friction coefficient and viscous damping coefficient.

[0012] Furthermore, the first solution step includes: a parameter selection step of selecting multiple adjustable parameters from a size parameter group, a performance response parameter group, a material parameter group and a contact performance parameter group; a setting level step of setting a numerical range and a number of numerical values ​​for each adjustable parameter; a setting matrix step of combining all adjustable parameters, numerical ranges and numbers of numerical values ​​according to an orthogonalization method to obtain an orthogonal matrix; performing simulation calculations based on the orthogonal matrix, and obtaining the optimal solution with the degree of fit between the first pressure curve and the first simulation pressure curve as the solution target.

[0013] Further, the plurality of adjustable parameters include one or more of initial pressure, viscosity coefficient, damping coefficient, Young's modulus, Poisson's ratio, secondary surface penalty stiffness coefficient, primary surface penalty stiffness coefficient, static friction coefficient, dynamic friction coefficient and viscous damping coefficient.

[0014] Furthermore, after the first solving step, the pressure simulation method further includes a correction step of correcting the first simulation data.

[0015] Furthermore, the correction step includes: a second test step of installing the pressure tube sensor to the whole vehicle and performing an impact test on the pressure tube; a second acquisition step of obtaining a second pressure curve of the pressures exerted on the opposite ends of the pressure tube within a preset time period; a second modeling step of establishing a collision simulation model of the pressure tube under the whole vehicle working condition, and inputting the first simulation data to obtain a second simulation pressure curve; a second solution step of matching and solving the second pressure curve and the second simulation pressure curve to obtain second simulation data, wherein the second simulation data includes a size parameter group, a material parameter group, a performance response parameter group and a contact parameter group.

[0016] Furthermore, before the second test step, the pressure simulation method further includes an impactor selection step of selecting impactors of different types; the second test step includes: making the entire vehicle and each impactor move relative to each other at a plurality of preset speeds to perform a collision test.

[0017] By applying the technical solution of the present invention, a drop test is performed on the pressure tube to obtain a first pressure curve, and a drop simulation model of the pressure tube is established to obtain a first simulation pressure curve. Then, the first pressure curve is used as a benchmark to make the first simulation pressure curve match the first pressure curve as much as possible. In this way, the first simulation data obtained by the drop simulation model can provide a basis for the performance design of the later active engine hood. Compared with the method of simply testing the pressure tube body material or directly testing the whole vehicle, the simulation method of this embodiment can not only solve the parameters corresponding to the material, size, performance response and contact performance of the pressure tube, but also reduce the influence of the front-end exterior and foam components of the whole vehicle. In this way, not only the accuracy of the pressure tube sensor simulation calibration is improved, but also the number of strikes in the whole vehicle test is reduced, so as to save the performance development cost of the active hood system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 A schematic flow chart showing a pressure simulation method for a pressure tube sensor according to an embodiment of the present invention;

[0020] Figure 2 Shows Figure 1 A schematic flow chart of a first solution step of a pressure simulation method;

[0021] Figure 3 Shows Figure 1 A flow chart of the correction steps of the pressure simulation method;

[0022] Figure 4 A schematic diagram showing the structure of a pressure tube sensor according to an embodiment of the present invention is shown;

[0023] Figure 5 A schematic diagram showing the structure of a drop device according to an embodiment of the present invention is shown;

[0024] Figure 6 A schematic diagram showing an impact test on a pressure pipe according to an embodiment of the present invention;

[0025] Figure 7 Shows Figure 6 BB sectional view; and

[0026] Figure 8 A schematic diagram showing the first simulation pressure curve of an embodiment of the present invention being consistent with the first pressure curve.

[0027] The above drawings include the following reference numerals:

[0028] 101. Pressure tube; 102. Pressure sensor; 201. Drop collider; 202. Mounting bracket; 203. Support frame; 204. Slide rail; 205. Support table; 301. Skin; 3002. Anti-collision beam foam; 3003. Anti-collision beam; 401. Protect PDI-2 leg collider; 402. Small animal collider; 403. Basketball collider; 404. Football collider; 405. Bird collider; 406. Stone collider; 407. Branch collider. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] During the development of traditional active hoods, due to the lack of high-precision simulation methods for pressure tube sensors, risk points in the design structure cannot be fully identified in the early stages, resulting in a large vehicle test matrix and a large number of tests and rounds, leading to a long performance development cycle and high costs.

[0031] Therefore, if Figure 1 and Figure 4 As shown, an embodiment of the present invention provides a pressure simulation method for a pressure tube sensor for an active pop-up hood. The pressure tube sensor includes a pressure tube 101 and two pressure sensors 102 arranged at opposite ends of the pressure tube 101. The pressure simulation method includes: a first test step of performing an impact test on the pressure tube 101; a first acquisition step of obtaining a first pressure curve of the pressures on the opposite ends of the pressure tube 101 within a preset time period; a first modeling step of establishing a drop simulation model of the pressure tube sensor to obtain a first simulation pressure curve; a first solution step of matching and solving the first pressure curve and the first simulation pressure curve to obtain first simulation data, wherein the first simulation data includes a size parameter group, a material parameter group, a performance response parameter group, and a contact performance parameter group.

[0032] In the above technical scheme, a drop test is performed on the pressure tube 101 to obtain a first pressure curve, and a drop simulation model of the pressure tube 101 is established to obtain a first simulation pressure curve. Then, the first pressure curve is used as a benchmark to make the first simulation pressure curve match the first pressure curve as much as possible. In this way, the first simulation data obtained by the drop simulation model can provide a basis for the performance design of the later active engine hood. Compared with the method of simply testing the main material of the pressure tube 101 or directly testing the whole vehicle, the simulation method of this embodiment can not only solve the parameters corresponding to the material, size, performance response and contact performance of the pressure tube 101, but also reduce the influence of the front-end exterior and foam components of the whole vehicle. In this way, not only the accuracy of the simulation calibration of the pressure tube sensor is improved, but also the number of strikes in the whole vehicle test is reduced, so as to save the performance development cost of the active hood system.

[0033] Specifically, in the embodiment of the present invention, the impact test on the pressure tube 101 is a component type test, which means that the pressure tube 101 is directly impacted without installing the pressure tube 101 to the whole vehicle to avoid other components affecting the test performance of the pressure tube 101.

[0034] It should be noted that, in the embodiment of the present invention, the first pressure curve and the first simulation pressure curve are both the relationship between pressure and time, that is, the pressure changes with time.

[0035] It should be noted that if Figure 8 As shown, in the embodiment of the present invention, the matching solution refers to taking the first pressure curve as a reference, selecting a first simulation pressure curve that is relatively close to the first pressure curve, that is, the first pressure curve and the first simulation pressure curve reach a preset matching degree, so that the values ​​of the size parameter group, material parameter group, performance response parameter group and contact performance parameter group of the drop simulation model corresponding to the first simulation pressure curve are the first simulation data. Among them, the preset matching degree is preferably 90%, that is, the matching degree of the first pressure curve and the first simulation pressure curve needs to reach 90% or more.

[0036] It should be noted that the preset degree of fit refers to the degree of similarity between the first pressure curve and the first simulation pressure curve in terms of curve peak value, curve peak time, curve phase, curve envelope area and curve shape.

[0037] The pressure simulation method of the pressure tube sensor for the active pop-up hood system of the present invention can effectively improve the accuracy of the pressure signal simulation in the early stage of the project, so that the design risks can be predicted in the early stage of development and the whole vehicle test of the active pop-up hood system can be reasonably planned through simulation, thereby achieving the effect of reducing the number of test matrices and test cycles.

[0038] Specifically, in an embodiment of the present invention, since the first modeling step needs to establish a model that is consistent with the component operating conditions in the first test step, the first test step is performed first, and then the first modeling step is performed; of course, there is no need to set a sequence between the first test step and the first modeling step, as long as the operating conditions of the first test step are designed first, and then the first test step or the first modeling step is performed.

[0039] Preferably, in an embodiment of the present invention, the pressure tube 101 is filled with gas at a certain pressure, and after the pressure tube 101 is squeezed or impacted, sensors at both ends can respectively record changes in pressure.

[0040] like Figure 5 As shown, in the embodiment of the present invention, the first test step includes using a drop impactor 201 to drop from multiple preset heights and perform impact tests on the pressure tube 101 respectively.

[0041] Through the above-mentioned arrangement, the drop impactor 201 can be used to simulate different impact energies on the pressure tube 101 by falling from multiple preset heights, so that multiple first pressure curves of the pressure tube 101 under multiple impact energies can be collected, and then a first simulation curve that matches the multiple first pressure curves is selected, which can improve the simulation accuracy of the pressure tube 101, and then the specific values ​​of the size parameter group, material parameter group, performance response parameter group and contact performance parameter group corresponding to the above-mentioned first simulation curve are solved by using the above-mentioned first simulation curve, so as to obtain accurate simulation parameters of the pressure tube 101, thereby providing accurate data for subsequent vehicle tests, which is helpful to improve the accuracy of the active hood misaction algorithm and reduce system misexplosions.

[0042] Preferably, in an embodiment of the present invention, the plurality of preset heights include three heights: high, medium and low, so as to simulate three types of impact energy: high, medium and low.

[0043] Specifically, Figure 5 As shown, in the embodiment of the present invention, the impact test is carried out by using a dedicated drop device, which includes a support platform 205 for placing the pressure tube sensor, two mounting brackets 202 arranged on the support platform 205 and spaced apart, and a drop impactor 201 located between the two mounting brackets 202; wherein, a guide groove is provided on one side of each mounting bracket 202 facing the drop impactor 201, and opposite ends of the drop impactor 201 are respectively slidably matched with the guide grooves of the two mounting brackets 202, so that the drop impactor 201 can be dropped from different heights in the vertical direction ( Figure 5 There are three different preset heights.

[0044] Specifically, Figure 5As shown, in an embodiment of the present invention, the drop device further includes a width adjuster, and a width adjuster is provided on a side of at least one mounting bracket 202 away from the drop impactor 201, and the width adjuster includes a support frame 203 connected to a support platform 205 and a slide rail 204 movably arranged in a horizontal direction relative to the support frame 203, and a slide groove arranged in a horizontal direction is provided on the support frame 203, one end of the slide rail 204 is slidably arranged in the slide groove, and the other end of the slide groove is connected to the mounting bracket 202. In this way, the interval between the two mounting brackets 202 can be adjusted, so that the drop device is suitable for impactors of different masses and volumes.

[0045] Preferably, in an embodiment of the present invention, the width adjuster includes a plurality of slide grooves spaced apart in the vertical direction and a plurality of slide rails 204 respectively arranged corresponding to the plurality of slide grooves.

[0046] Preferably, in the embodiment of the present invention, the preset height H i Satisfy the formula: Where M0 is the equivalent mass of the impact on the human body or the mass of the standard impactor, V i is the relative speed of the impactor, M is the mass of the falling impactor 201, g is the gravitational acceleration, H i V i Corresponding different preset heights.

[0047] Through the above arrangement, different drop heights of the same drop impactor 201 in the drop test can be calculated through different speeds of the same impactor relative to the pressure tube 101, so that different impact energies on the pressure sensor 102 can be simulated.

[0048] It should be noted that the speed of Vi can be multiple. Preferably, Vi can be the equivalent impact speed of 25km / h for low energy intensity, 32km / h for medium energy intensity, and 40km / h for high energy intensity. In this way, the different heights corresponding to low energy, medium energy and high energy can be calculated.

[0049] It should be noted that M0 is the equivalent mass of a human body or the mass of a standard striker, which is a selectable standard value.

[0050] Of course, in an alternative embodiment not shown in the drawings, different masses of drop impactors 201 may be selected to fall from the same height, as long as different impact energies can be simulated. i , to calculate the masses of different falling impactors 201, that is, different masses of falling impactors 201 can be used to fall from the same height to simulate different impact energies.

[0051] Of course, different drop impactors 201 may be dropped from different heights, as long as the three impact energies of low, medium and high can be simulated.

[0052] like Figure 1 As shown, in an embodiment of the present invention, after the first acquisition step and before the first solution step, the pressure simulation method also includes a judgment step of judging whether the two first pressure curves obtained from the two ends of the pressure tube 101 are consistent, if yes, executing the first solution step, if not, executing the first test step.

[0053] Through the above settings, it can be determined whether the falling impactor 201 hits the center position of the pressure tube 101 in its own length direction. If yes, the impact is the above center position. If not, the impact position deviates from the above center position. The pressure curve generated by the falling impactor 201 hitting the center position of the pressure tube 101 can more accurately represent the change of the pressure of the pressure tube 101 over time. In this way, the above steps can enable the simulation method to obtain the first simulation data more accurately, thereby improving the accuracy of the simulation calibration of the pressure tube sensor.

[0054] Preferably, in an embodiment of the present invention, in the first test step, the center position of the pressure tube 101 in its own length direction is selected as the impact position of the drop impactor 201. If the drop impactor 201 hits the center position of the pressure tube 101, theoretically, the signals at both ends of the pressure tube 101 should be consistent.

[0055] It should be noted that, in the embodiment of the present invention, the two first pressure curves are consistent, which means that the peak values ​​of the two first pressure curves coincide with each other by 90% or more.

[0056] Specifically, in an embodiment of the present invention, the first modeling step includes: a first simulation step of inputting initial values ​​of a size parameter group of the pressure tube 101 to simulate the shape of the pressure tube 101; a second simulation step of inputting initial values ​​of a performance response parameter group of the pressure tube 101 to simulate the performance response capability of the pressure tube 101; a third simulation step of inputting initial values ​​of a material parameter group of the pressure tube 101 to simulate the material of the pressure tube 101; and a fourth simulation step of inputting initial values ​​of a contact performance parameter group of the pressure tube 101 to simulate the contact between the pressure tube 101 and the drop impactor 201.

[0057] In the above technical solution, when establishing the drop simulation model of the pressure tube sensor, an initial value is selected for each parameter in the size parameter group, performance response parameter group, material parameter group and contact performance parameter group (the operator can arbitrarily select a numerical value based on experience, etc.). In this way, an initial pressure tube 101 drop simulation model can be formed to simulate an initial first simulation pressure curve to facilitate subsequent solution calculations.

[0058] Furthermore, compared with simply testing the main material of the pressure tube 101, the simulation method of this embodiment can also simulate the size of the pressure tube 101, as well as the performance response and contact performance of the pressure tube 101 under impact conditions.

[0059] Specifically, in an embodiment of the present invention, Ls-dyna software is used to establish a drop simulation model of a pressure tube sensor under a drop test condition, that is, the length of the pressure tube 101, the fixed position of the pressure tube 101, the drop height of the drop impactor 201 and the mass of the drop impactor 201 are consistent with the drop test conditions, but the modeling software is not limited to the above software.

[0060] Preferably, the embodiment of the present invention uses the beam unit in the Ls-dyna software to simulate the cross-sectional dimensions of the pressure tube 101 and the length of the pressure tube 101, wherein the length of the pressure tube 101 is preferably 1 mm. Of course, in alternative embodiments not shown in the drawings, the length of the pressure tube 101 may also be other lengths.

[0061] It should be noted that, in the embodiment of the present invention, the performance response refers to the deformation capacity of the pressure pipe 101 and the like.

[0062] Specifically, in an embodiment of the present invention, the performance response capability of the pressure tube 101 is simulated using the DEFINE_PRESSURE_TUBE card in the Ls-dyna software; the material of the pressure tube 101 is simulated using the MAT_PLASTIC_KINEMATIC material constitutive in the Ls-dyna software; and the contact between the pressure tube 101 and the drop impactor 201 is simulated using the CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_MORTAR in the Ls-dyna software.

[0063] Preferably, in an embodiment of the present invention, the size parameter group includes the length dimension of the pressure tube 101 and the cross-sectional area dimension of the pressure tube 101 , so that the dimension of the pressure tube 101 can be accurately simulated.

[0064] Preferably, in an embodiment of the present invention, the performance response parameter group includes the speed of sound, the initial pressure, the viscosity coefficient and the damping coefficient, so that the deformation capacity of the pressure pipe 101 can be simulated.

[0065] Preferably, in an embodiment of the present invention, the material parameter group includes density, Young's modulus, Poisson's ratio, yield strength and tangent modulus, so that the material of the pressure pipe 101 can be simulated.

[0066] Preferably, in an embodiment of the present invention, the contact performance parameter group includes a secondary surface penalty stiffness coefficient, a primary surface penalty stiffness coefficient, a static friction coefficient, a dynamic friction coefficient and a viscous damping coefficient, so that the contact between the pressure tube 101 and the drop impactor 201 can be simulated.

[0067] Through the above settings, the simulation curve can be made to be closer to the first pressure curve in the impact test more accurately, so as to provide a more accurate basis for subsequent vehicle tests.

[0068] like Figure 2 As shown, in an embodiment of the present invention, the first solution step includes: a parameter selection step of selecting multiple adjustable parameters from a size parameter group, a performance response parameter group, a material parameter group, and a contact performance parameter group; a level setting step of setting a numerical range and a number of numerical values ​​for each adjustable parameter; a matrix setting step of combining all adjustable parameters, numerical ranges, and numbers of numerical values ​​according to an orthogonalization method to obtain an orthogonal matrix; performing simulation calculations based on the orthogonal matrix, and obtaining an optimal solution with the degree of fit between the first pressure curve and the first simulation pressure curve as the solution target.

[0069] Through the above settings, multiple values ​​are selected within the numerical range of each adjustable parameter to form multiple first simulation pressure curves, and then the first pressure curve is used as a reference to select a first simulation pressure curve that matches the first pressure curve from the multiple first simulation pressure curves. In this way, the parameters corresponding to the first simulation pressure curve that meets the matching requirements are the optimal solution. In this way, the specific values ​​of the first simulation data can be obtained, which can provide a basis for the performance design of the later active engine hood.

[0070] It should be noted that, in the embodiments of the present invention, adjustable parameters refer to parameters in the size parameter group, performance response parameter group, material parameter group and contact performance parameter group that can be changed and have an impact on one or more of the pressure signal peak value, pressure signal peak width and pressure signal attenuation characteristics.

[0071] It should be noted that, in an embodiment of the present invention, in the level setting step, it is necessary to set a variation range for the numerical value of each adjustable parameter, and then select multiple numerical values ​​within the variation range of each adjustable parameter, and the intervals between two adjacent numerical values ​​in the multiple numerical values ​​are equal, wherein the first simulation pressure curve corresponding to the initial values ​​of all parameters in the input dimension parameter group, material parameter group, performance response parameter group and contact performance parameter group is different from the first pressure curve, and then the technician designs the numerical range and number of values ​​of each adjustable parameter based on design experience and the above differences.

[0072] Specifically, in the embodiment of the present invention, by setting an orthogonal matrix, the number of calculated samples can be reduced, thereby reducing the amount of calculation.

[0073] Specifically, in an embodiment of the present invention, simulation calculation based on an orthogonal matrix refers to substituting multiple numerical values ​​selected from each adjustable parameter into the drop simulation model of the pressure tube 101 in an iterative manner to form multiple first simulation pressure curves, and then selecting a first simulation pressure curve that matches the first pressure curve from the multiple first simulation pressure curves. The dimensional parameter group, material parameter group, performance response parameter group and contact performance parameter group corresponding to this first simulation pressure curve are the first simulation data (optimal solution).

[0074] Specifically, in an embodiment of the present invention, when matching and solving the first pressure curve and the first simulation pressure curve, it is necessary to make the first simulation pressure curve match the first pressure curves under high, medium and low energies respectively, that is, select a first simulation pressure curve from multiple first simulation pressure curves that can match the first pressure curve under high energy conditions, the first pressure curve under medium energy conditions, and the first pressure curve under low energy conditions.

[0075] Preferably, in an embodiment of the present invention, the multiple adjustable parameters include one or more of initial pressure, viscosity coefficient, damping coefficient, Young's modulus, Poisson's ratio, secondary surface penalty stiffness coefficient, primary surface penalty stiffness coefficient, static friction coefficient, dynamic friction coefficient and viscous damping coefficient.

[0076] In the above technical scheme, by selecting the above parameters and changing the numerical values ​​of the above parameters, the peak value of the pressure signal, the peak width of the pressure signal and the attenuation characteristics of the pressure signal of the pressure tube 101 can be changed. In this way, by substituting different numerical values ​​into the above parameters, different first simulation pressure curves can be obtained, and then the first simulation pressure curve that can satisfy the three first pressure curves corresponding to high, medium and low energy impacts is selected. In this way, the optimal parameters of the pressure tube 101 under the drop test conditions can be obtained.

[0077] Specifically, the influence of each adjustable parameter on the pressure signal of the pressure tube 101 is shown in Table 1:

[0078] Table 1: Effect of each adjustable parameter on the pressure signal of the pressure tube 101

[0079]

[0080] By changing the above parameters, the pressure signal peak value, the pressure signal peak width, and the pressure signal attenuation characteristics of the first simulation pressure curve can be changed, thereby changing the first simulation pressure curve.

[0081] By using the above steps, on the one hand, the parameter range of the pressure pipe 101 can be gradually narrowed, so as to provide a basis for the subsequent vehicle development; on the other hand, in the early stage of project development, that is, when there is no vehicle simulation working condition, a more accurate parameter value of the pressure pipe 101 can be obtained.

[0082] like Figure 1 As shown, in an embodiment of the present invention, after the first solving step, the pressure signal simulation method further includes a correction step of correcting the first simulation data.

[0083] In the above technical solution, the first simulation data can be corrected by setting a correction step, thereby increasing the accuracy of the simulation calibration of the pressure tube sensor.

[0084] like Figure 3 As shown, in an embodiment of the present invention, the correction step includes: a second test step of installing a pressure tube sensor to the whole vehicle and performing an impact test on the pressure tube 101; a second acquisition step of obtaining a second pressure curve of the pressures exerted on the opposite ends of the pressure tube 101 within a preset time period; a second modeling step of establishing a collision simulation model of the pressure tube 101 under the whole vehicle working condition, and inputting the first simulation data to obtain a second simulation pressure curve; a second solution step of matching and solving the second pressure curve and the second simulation pressure curve to obtain second simulation data, wherein the second simulation data includes a size parameter group, a material parameter group, a performance response parameter group and a contact parameter group.

[0085] In the above technical scheme, after obtaining the parameter value of the pressure tube sensor under the component working condition (i.e., the working condition under the drop test), the second pressure curve is obtained by simulating the whole vehicle impact condition, and the solved first simulation data is input to establish a simulation model of the pressure tube 101 under the whole vehicle working condition to obtain the second simulation pressure curve, and then the second pressure curve is used as a reference to make the second simulation pressure curve match the second pressure curve as much as possible. In this way, the parameter value obtained in the first solving step can be corrected, so that the obtained second simulation data is more accurate than the first simulation data, providing a basis for the design of the pressure tube sensor in the subsequent whole vehicle design stage.

[0086] Furthermore, the pressure simulation method of this embodiment can gradually approach the optimal design parameters of the pressure pipe 101 under actual working conditions, thereby solving the problem of large deviation between simulation results and actual results in the prior art.

[0087] It should be noted that, in the embodiment of the present invention, the collision simulation model of the pressure tube 101 refers to a model of the pressure tube 101 under the whole vehicle working condition, so as to simulate the pressure tube 101 under the whole vehicle working condition.

[0088] It should be noted that the correction step is to perform local fine-tuning on the first simulation data so as to correct the first simulation data.

[0089] It should be noted that, in the embodiment of the present invention, similarly, the second solution step includes a parameter selection step, a level setting step, a matrix setting step, and a simulation calculation, and a step of obtaining an optimal solution with the degree of fit between the first pressure curve and the first simulation pressure curve as the solution target. Among them, after inputting the first simulation data into the collision simulation model of the pressure tube 101, the pressure signal peak width of the second simulation pressure curve obtained will be different from that of the pressure curve of the first simulation data under the component working condition, and then the technicians design the value range and number of values ​​of each adjustable parameter based on the design experience and the above differences.

[0090] Specifically, Figure 7 As shown, in an embodiment of the present invention, the whole vehicle includes a frame, a skin 301 covering the frame, an anti-collision beam 3003 located between the front end of the frame and the skin 301, and an anti-collision beam foam 3002 located between the anti-collision beam 3003 and the skin 301, and an installation groove is provided on the side of the anti-collision beam foam 3002 facing the anti-collision beam 3003, a part of the pressure pipe 101 is arranged in the installation groove, and the part of the pressure pipe 101 exposed from the installation groove is connected to the anti-collision beam 3003.

[0091] Specifically, Figure 3 As shown, in the embodiment of the present invention, since the second modeling step needs to establish a model consistent with the whole vehicle operating condition in the second test step, the second test step is performed first, and then the second modeling step is performed; of course, there is no need to set a sequence between the second test step and the second modeling step, as long as the whole vehicle operating condition of the second test step is designed first, and then the second test step or the second modeling step is performed.

[0092] Specifically, in an embodiment of the present invention, after the second acquisition step and before the second solution step, the pressure simulation method also includes a judgment step of judging whether the two second pressure curves obtained from the two ends of the pressure tube 101 are consistent, if so, executing the second solution step, if not, executing the second test step.

[0093] Through the above settings, it can be determined whether the impactor hits the center position of the pressure tube 101 in its length direction. If yes, the impact is the above center position. If not, the impact position deviates from the above center position. The pressure curve generated by the impactor hitting the center position of the pressure tube 101 can more accurately represent the change of the pressure of the pressure tube 101 over time. In this way, the above steps can enable the simulation method to obtain the second simulation data more accurately, thereby improving the accuracy of the simulation calibration of the pressure tube sensor.

[0094] like Figure 6 As shown, in an embodiment of the present invention, before the second test step, the pressure simulation method further includes a collision device selection step of selecting collision devices of different types; the second test step includes: making the whole vehicle and each collision device move relative to each other at a plurality of preset speeds to perform a collision test.

[0095] Through the above-mentioned arrangement, each collider can be used to impact the whole vehicle at a variety of preset speeds to simulate the different impact energies of each collider on the pressure tube 101 under the whole vehicle working condition. In this way, multiple second pressure curves of the pressure tube 101 under the whole vehicle working condition and multiple impact energies can be collected, and then a second simulation curve that matches the multiple second pressure curves is selected, which can improve the simulation accuracy of the pressure tube 101. Then, the second simulation curve is used to solve the specific values ​​of the size parameter group, material parameter group, performance response parameter group and contact performance parameter group corresponding to the second simulation curve, so as to obtain accurate simulation parameters of the pressure tube 101, which is helpful to improve the accuracy of the active hood misaction algorithm and reduce system misexplosion.

[0096] Preferably, in an embodiment of the present invention, the plurality of preset speeds include three speeds of 25 km / h, 32 km / h and 40 km / h, so as to simulate small, medium and large impact energies.

[0097] like Figure 6 As shown, different types of colliders include pedestrian protection PDI-2 leg collider 401, small animal collider 402, basketball collider 403, football collider 404, bird collider 405, stone collider 406, branch collider 407, etc., but are not limited to the above colliders.

[0098] It should be noted that, in the embodiment of the present invention, the degree of fit between the second pressure curve and the second simulation pressure curve reaches the index of the fit solution: the curve peak value, curve peak time, curve phase, curve envelope area, and curve shape of the second pressure curve obtained by testing the pedestrian protection PDI-2 leg-type impactor 401 or the small animal impactor 402 are ≥80% consistent with the second simulation curve; the degree of fit between the second pressure curve obtained by testing the remaining impactors except the pedestrian protection PDI-2 leg-type impactor 401 and the small animal impactor 402 and the second simulation curve is ≥70%.

[0099] It should be noted that in the system development of the active pop-up hood, high-precision pressure simulation methods are particularly important: in the early stages of vehicle development, especially in the styling and layout stages, identifying design risks through high-precision simulation can effectively improve later design iterations and reduce the performance development cycle, and reduce the false explosion rate of the active pop-up hood system.

[0100] From the above description, it can be seen that the above-mentioned embodiment of the present invention achieves the following technical effects: by performing a drop test on the pressure tube to obtain a first pressure curve, and establishing a drop simulation model of the pressure tube to obtain a first simulation pressure curve, and then taking the first pressure curve as a benchmark, the first simulation pressure curve is made to match the first pressure curve as much as possible. In this way, the first simulation data obtained by the drop simulation model can provide a basis for the performance design of the later active engine hood. Compared with the method of simply testing the pressure tube body material or directly testing the whole vehicle, the simulation method of this embodiment can not only solve the parameters corresponding to the material, size, performance response and contact performance of the pressure tube, but also reduce the influence of the front-end exterior and foam components of the whole vehicle. In this way, not only the accuracy of the pressure tube sensor simulation calibration is improved, but also the number of strikes in the whole vehicle test is reduced, so as to save the performance development cost of the active hood system.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pressure simulation method for a pressure tube sensor for an active pop-up hood, the pressure tube sensor comprising a pressure tube (101) and two pressure sensors (102) arranged at opposite ends of the pressure tube (101), characterized in that: The pressure simulation method comprises: A first test step of performing an impact test on the pressure pipe (101); A first acquisition step of acquiring a first pressure curve of the pressures applied to the two opposite ends of the pressure tube (101) within a preset time period; A first modeling step of establishing a drop simulation model of the pressure tube sensor to obtain a first simulation pressure curve; A first solving step of matching and solving the first pressure curve and the first simulation pressure curve to obtain first simulation data, wherein the first simulation data includes a size parameter group, a material parameter group, a performance response parameter group, and a contact performance parameter group; The first test step comprises using a drop impactor (201) to drop from a plurality of preset heights and respectively perform impact tests on the pressure tube (101); The preset height Hi satisfies the formula: Among them, M o is the equivalent mass that hits the human body or the mass of the standard impactor, V i is the relative speed of the impactor, M is the mass of the falling impactor (201), g is the gravitational acceleration, H i V i Corresponding different preset heights; The first solving step comprises: A parameter selection step of selecting a plurality of adjustable parameters from the size parameter group, the performance response parameter group, the material parameter group and the contact performance parameter group; A setting level step of setting a range of values ​​and the number of values ​​of each of the adjustable parameters; A step of setting a matrix by combining all the adjustable parameters, the numerical ranges and the number of numerical values ​​according to an orthogonalization method to obtain an orthogonal matrix; A simulation calculation is performed according to the orthogonal matrix, and an optimal solution is obtained by taking the degree of agreement between the first pressure curve and the first simulation pressure curve as a solution target.

2. The pressure simulation method according to claim 1, characterized in that: After the first acquisition step and before the first solution step, the pressure simulation method further comprises a judgment step of judging whether the two first pressure curves obtained from the two ends of the pressure tube (101) are consistent; if so, executing the first solution step; if not, executing the first test step.

3. The pressure simulation method according to claim 1, characterized in that: The first modeling step comprises: A first simulation step of inputting initial values ​​of a set of dimension parameters of the pressure tube (101) to simulate the shape of the pressure tube (101); A second simulation step of inputting initial values ​​of a performance response parameter group of the pressure pipe (101) to simulate the performance response capability of the pressure pipe (101); A third simulation step of inputting initial values ​​of a material parameter group of the pressure pipe (101) to simulate the material of the pressure pipe (101); The initial values ​​of the contact performance parameter group of the pressure tube (101) are input to simulate the fourth simulation step of the contact between the pressure tube (101) and the drop impactor (201).

4. The pressure simulation method according to claim 3, characterized in that: The size parameter group includes at least one of a length dimension of the pressure pipe (101) and a cross-sectional area dimension of the pressure pipe (101); or, The performance response parameter group includes at least one of the velocity of sound, initial pressure, viscosity coefficient and damping coefficient; or, The material parameter group includes at least one of density, Young's modulus, Poisson's ratio, yield strength and tangent modulus; or, The contact performance parameter group includes at least one of a secondary surface penalty stiffness coefficient, a primary surface penalty stiffness coefficient, a static friction coefficient, a dynamic friction coefficient and a viscous damping coefficient.

5. The pressure simulation method according to claim 1, characterized in that: The plurality of adjustable parameters include one or more of initial pressure, viscosity coefficient, damping coefficient, Young's modulus, Poisson's ratio, secondary surface penalty stiffness coefficient, primary surface penalty stiffness coefficient, static friction coefficient, dynamic friction coefficient and viscous damping coefficient.

6. The pressure simulation method according to claim 1, characterized in that: After the first solving step, the pressure simulation method further includes a correction step of correcting the first simulation data.

7. The pressure simulation method according to claim 6, characterized in that: The correction steps include: The second test step of installing the pressure pipe sensor on a whole vehicle and performing an impact test on the pressure pipe (101); A second acquisition step of acquiring a second pressure curve of the pressures exerted on the opposite ends of the pressure tube (101) within a preset time period; Under the whole vehicle working condition, a collision simulation model of the pressure pipe (101) is established, and the first simulation data is input to obtain a second modeling step of a second simulation pressure curve; The second pressure curve and the second simulation pressure curve are matched and solved to obtain a second solution step of second simulation data, wherein the second simulation data includes a size parameter group, a material parameter group, a performance response parameter group and a contact parameter group.

8. The pressure simulation method according to claim 7, characterized in that: Before the second test step, the pressure simulation method further includes an impactor selection step of selecting impactors of different types; The second test step comprises: The whole vehicle and each of the impactors are made to move relative to each other at a plurality of preset speeds to perform a collision test.

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