Front 25% offset collision sliding table test method based on dummy off-location displacement

Abstract

The invention relates to the technical field of simulated collision tests, in particular to a front 25% offset collision sliding table test method based on dummy off-location displacement, which comprises the following steps: S1, acquiring acceleration change data of a whole vehicle body and a dummy in a front 25% offset collision test of a real vehicle; s2, determining the acceleration waveform of the sliding table test according to the X-direction acceleration change data obtained in S1; and S3, determining the body-in-white deflection angle of the sliding table test according to the dummy acceleration change data obtained in S1. According to the invention, a standardized sliding table test parameter setting process can be provided for the sliding table collision test, the set sliding table test parameters are closer to a real vehicle collision test, video analysis does not need to be carried out on the real vehicle collision process, the calculated amount is small, and the data repeatability is high.

Description

Technical Field

[0001] The invention relates to the technical field of simulated collision tests, in particular to a frontal 25% offset collision slide test method based on dummy off-position displacement. Background Art

[0002] In driving traffic accidents, frontal collisions account for about 40% of the accident rate, and the proportion of offset collisions with a small overlap rate can reach 25%, which will cause serious injuries to the occupants in the car and are high-incidence and high-risk accidents. Research on this type of accident can effectively improve the safety of occupants in the car, reduce the R&D costs of car companies, and shorten the R&D cycle. Therefore, the 25% offset frontal collision test in the safety index has become the focus of attention of the industry and consumers. During the collision, the seat belts, car seats, airbags and other components of the real vehicle restraint system have a great impact on the movement and injury of the occupants. However, the cost of real vehicle collision tests is high and the cycle is long, which causes many inconveniences to systematic optimization. Automobile companies are more likely to use slide table simulation collision tests to achieve low-cost and short-time collision test results.

[0003] However, the existing slide table simulation collision test still has defects: in the real vehicle collision test, the vehicle body will produce a large angle of deflection around the Z axis, while the slide table can only achieve single-degree-of-freedom movement. Therefore, the traditional slide table simulation test scheme cannot accurately restore the real vehicle collision condition. It is necessary to input the acceleration waveform to the slide table to simulate the actual acceleration process of the vehicle. At the same time, the corresponding deflection angle is set in the collision direction between the body-in-white and the slide table to simulate the lateral impact of the dummy during the actual collision process. At present, there is no unified and effective implementation plan for the adjustment process of the acceleration waveform and the deflection angle of the body-in-white. If the adjustment method is inappropriate, it will lead to a large difference between the injury results of the simulated collision test and the occupant injury results in the real vehicle collision test. Summary of the invention

[0004] The present invention provides a frontal 25% offset collision slide test method based on dummy off-position displacement, which can provide a standardized slide test parameter setting process for the slide collision test. The set slide test parameters are closer to the actual vehicle collision test. At the same time, there is no need to perform video analysis on the actual vehicle collision process, the calculation amount is small, and the data repeatability is high.

[0005] This application provides the following technical solutions:

[0006] A frontal 25% offset collision slide test method based on dummy displacement, comprising the following steps:

[0007] S1. Collect acceleration change data of the vehicle body and dummy in the 25% offset frontal collision test of the real vehicle;

[0008] S2, determining the acceleration waveform of the sliding table test according to the X-axis acceleration change data obtained in S1;

[0009] S3. Determine the body-in-white deflection angle of the sliding table test according to the dummy acceleration change data obtained in S1.

[0010] Technical principle: Based on a 25% offset frontal collision of a real vehicle, the acceleration curve of the actual vehicle and the acceleration data of the dummy's chest at the driver's position are collected, and the off-position trajectory motion curve of the dummy's chest is obtained by quadratic integration of the acceleration change curve of the dummy's chest. The part from zero displacement to maximum displacement in the off-position trajectory motion curve is intercepted for linear regression fitting, and the deflection angle of the vehicle is solved by the coefficient of the obtained linear regression function. The X-axis acceleration curve of the vehicle body corresponding to the dummy's chest position is used as the acceleration waveform of the sliding table test, and the solved offset angle is used as the deflection angle of the white body in the sliding table test.

[0011] Beneficial effects: In the test waveform selection method, this solution directly collects the acceleration of the base plate corresponding to the chest position of the real vehicle dummy, and obtains the real acceleration experienced by the dummy in the vehicle coordinate system; in the deflection angle selection method, this solution obtains the deflection angle based on the dummy's displacement data, pays more attention to the movement of the dummy relative to the vehicle body, and can better simulate the real vehicle collision situation;

[0012] This scheme does not require video analysis, is simple to calculate, and has good repeatability.

[0013] Further, the S1 includes:

[0014] S11. Attach the first set of acceleration sensors to the lower edges of the B-pillars on the left and right sides of the vehicle body:

[0015] S12, attaching a second set of acceleration sensors to the dummy's chest; attaching a third set of acceleration sensors to the vertical projection of the bottom plate at the dummy's chest;

[0016] S13. Conduct a 25% offset frontal collision test on a real vehicle and collect data.

[0017] Furthermore, in S2, the X-axis acceleration curve collected by the third group of acceleration sensors in S13 is used as the acceleration waveform of the sliding table test.

[0018] Further, the S3 includes:

[0019] S31, calculating the displacement of the dummy's chest in the X direction and the Y direction;

[0020] S32, drawing a motion trajectory curve of the dummy's chest relative to the vehicle body;

[0021] S33, performing linear regression fitting according to the motion trajectory curve;

[0022] S34. Solve the initial deflection angle of the sliding table test according to the linear regression function determined in S33.

[0023] Further, in S31, the X-direction acceleration curve collected by the third group of acceleration sensors is integrated twice with respect to time to obtain the X-direction displacement S of the reference point of the front test seat. xref ; The X-direction acceleration curve collected by the second group of acceleration sensors is integrated twice with respect to time to obtain the X-direction displacement S of the dummy chest xchest , calculate S xchest and S xref The difference between the values ​​of x ;

[0024] The Y-direction acceleration curve collected by the third group of acceleration sensors is integrated twice with respect to time to obtain the Y-direction displacement S of the reference point of the front test seat. yref ; The Y-direction acceleration curve collected by the second group of acceleration sensors is integrated twice with respect to time to obtain the Y-direction displacement S of the dummy chest ychest , calculate S ychest and S yref The difference between the two values ​​is used to obtain the Y-direction displacement ΔS of the dummy chest. y .

[0025] Further, the S33 intercepts the motion trajectory curve of the dummy in the X direction from the initial displacement to the maximum displacement, and constructs a linear regression function reflecting the collision motion response of the dummy for the intercepted curve, and its expression is as follows:

[0026] Y chest =a*x chest +b chest

[0027] Among them, Y chest is the displacement of the dummy in the Y direction, a is the coefficient of the regression function, x chest is the displacement of the dummy in the X direction, b chest is the intercept of the regression function.

[0028] Further: In S34, the initial deflection angle θ of the front 25% offset collision slide test is obtained by using an inverse trigonometric function, as shown in the following formula:

[0029] θ=arctan(a)

[0030] Among them, θ is the initial deflection angle of the collision slide test section, and a is the slope of the regression function constructed by S33. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the position of the dummy chest sensor corresponding to the chassis in the collision test;

[0032] Figure 2 Schematic diagram of the motion trajectory of the dummy's chest relative to the vehicle body. DETAILED DESCRIPTION

[0033] The following is further described in detail through specific implementation methods:

[0034] Embodiment 1

[0035] A frontal 25% offset collision slide test method based on dummy displacement, comprising the following steps:

[0036] S1. Collect acceleration change data of the vehicle body and dummy in the 25% offset frontal collision test of the real vehicle, including:

[0037] S11. Attach the first set of acceleration sensors to the lower edges of the B-pillars on the left and right sides of the vehicle body:

[0038] The data collected by the first group of acceleration sensors is used to reflect the acceleration changes of the vehicle body during the test. The acceleration sensors collect acceleration data in three directions at the same time.

[0039] S12. Attach a second set of acceleration sensors to the dummy's chest; attach a third set of acceleration sensors to the vertical projection of the bottom plate at the dummy's chest:

[0040] In the frontal 25% offset collision test, the dummy's chest is significantly restrained by the system during the collision and is located in the middle of the dummy's body. Its motion trajectory can better represent the dummy's motion trend. In order to obtain the actual acceleration experienced by the dummy in the vehicle coordinate system, a second set of acceleration sensors is attached to the dummy's chest and used as the basic data for calculating the dummy's chest motion trajectory, such as Figure 1 shown.

[0041] When a collision occurs, the dummy's chest will be displaced relative to the seat, so a third set of acceleration sensors is attached to the vertical projection of the dummy's chest on the floor to collect the acceleration of the actual vehicle floor and serve as the basic data for calculating the movement trajectory of the vehicle seat. The acceleration sensor can collect acceleration change data in three directions at the same time.

[0042] S13. Conduct a 25% offset frontal collision test on a real vehicle and collect data.

[0043] S2. Determine the acceleration waveform of the sliding table test according to the dummy's X-axis acceleration change data obtained in S1.

[0044] The X-axis acceleration curve collected by the third group of acceleration sensors in S13 is used as the acceleration waveform of the sliding table test. Compared with the traditional scheme, this scheme directly obtains the real acceleration experienced by the dummy in the vehicle coordinate system and selects it as the test waveform, which is closer to the test data of the real vehicle collision.

[0045] S3. Determine the body-in-white deflection angle of the sliding table test according to the dummy acceleration change data obtained in S1.

[0046] The chest is located in the center of the human body and is significantly restrained by the system during a collision. Its movement trend can better represent the overall movement trend of the human body. Therefore, a motion trajectory curve of the dummy's chest relative to the vehicle body is constructed. This motion trajectory curve can intuitively reflect the dummy's movement trend relative to the vehicle body in a 25% offset frontal collision, and further seek a suitable vehicle body deflection angle based on this motion trajectory curve.

[0047] Specifically, S3 includes the following steps:

[0048] S31. Calculate the displacement of the dummy's chest in the X and Y directions:

[0049] According to the above scheme, the X-axis acceleration curve collected by the third group of acceleration sensors is the X-axis acceleration curve a of the driver's chest corresponding to the chassis. xref , and the X-direction displacement S of the reference point of the front test seat is obtained by integrating the time twice xref The X-axis acceleration curve collected by the second group of acceleration sensors is the X-axis acceleration signal a of the dummy chest. xchest , and the X-direction displacement S of the dummy chest is obtained by integrating the time twice xchest , as shown below:

[0050]

[0051]

[0052] Calculate the difference between the two and get the X-direction displacement ΔS of the dummy chest x , as shown below:

[0053] ΔS x =S xchest -S xref

[0054] Similarly, the Y-direction displacement ΔS of the dummy chest is obtained y , as shown below:

[0055]

[0056] ΔS y =S ychest -S yref

[0057] S32. Draw the motion trajectory curve of the dummy's chest relative to the vehicle body:

[0058] According to the X-direction displacement of the dummy chest ΔS x Y-direction displacement of the dummy's chest ΔS y , draw the motion trajectory of the dummy's chest relative to the vehicle body, such as Figure 2 Shown as the blue curve in the middle.

[0059] S33, perform linear regression fitting according to the motion trajectory curve:

[0060] In the motion response of the dummy to the collision, when the collision occurs, the speed of the vehicle body decreases rapidly, and the dummy is displaced by inertia, resulting in a gradually increasing displacement; when the dummy is restricted by the protection of the restraint system and reaches the maximum displacement, that is, the displacement of the dummy will no longer increase. Therefore, the data segment that can truly reflect the displacement of the dummy during the collision is the data segment from zero displacement to maximum displacement in the X direction. Therefore, the motion trajectory curve of the dummy in the X direction from the beginning of displacement to the maximum displacement is intercepted, such as Figure 2 The part within the blue frame is shown in the figure.

[0061] Based on the motion trajectory curve intercepted in the blue wireframe, a linear regression function is constructed to accurately reflect the motion response of the dummy during the collision process, such as Figure 2 As shown by the red curve in the figure, its expression is as follows:

[0062] Y chest =a*x chest +b chest

[0063] Among them, Y chest is the displacement of the dummy in the Y direction, a is the coefficient of the regression function, x chest is the displacement of the dummy in the X direction, b chest is the intercept of the regression function.

[0064] S34, solving the initial deflection angle of the sliding table test according to the linear regression function determined in S33:

[0065] Based on the slope a of the linear regression curve that has been determined, the initial deflection angle θ of the frontal 25% offset collision slide test is obtained using the inverse trigonometric function, as shown in the following formula:

[0066] θ=arctan(a)

[0067] The above are only embodiments of the present invention. The invention is not limited to the field involved in this implementation case. The common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A frontal 25% offset collision slide test method based on dummy displacement, characterized in that: The following steps are involved: S1. Collect acceleration change data of the vehicle body and dummy in the 25% offset frontal collision test of the real vehicle; S2, determining the acceleration waveform of the sliding table test according to the X-axis acceleration change data obtained in S1; S3. Determine the body-in-white deflection angle of the sliding table test according to the dummy acceleration change data obtained in S1.

2. A frontal 25% offset collision slide test method based on dummy displacement according to claim 1, characterized in that: The S1 includes: S11. Attach the first set of acceleration sensors to the lower edges of the B-pillars on the left and right sides of the vehicle body: S12, attaching a second set of acceleration sensors to the dummy's chest; attaching a third set of acceleration sensors to the vertical projection of the bottom plate at the dummy's chest; S13. Conduct a 25% offset frontal collision test on a real vehicle and collect data.

3. A frontal 25% offset collision slide test method based on dummy displacement according to claim 2, characterized in that: In S2, the X-axis acceleration curve collected by the third group of acceleration sensors in S13 is used as the acceleration waveform of the sliding table test.

4. A frontal 25% offset collision slide test method based on dummy displacement according to claim 3, characterized in that: The S3 includes: S31, calculating the displacement of the dummy's chest in the X direction and the Y direction; S32, drawing a motion trajectory curve of the dummy's chest relative to the vehicle body; S33, performing linear regression fitting according to the motion trajectory curve; S34. Solve the initial deflection angle of the sliding table test according to the linear regression function determined in S33.

5. A frontal 25% offset collision slide test method based on dummy displacement according to claim 4, characterized in that: In S31, the X-direction acceleration curve collected by the third group of acceleration sensors is integrated twice with respect to time to obtain the X-direction displacement S of the test seat reference point. xref ; The X-direction acceleration curve collected by the second group of acceleration sensors is integrated twice with respect to time to obtain the X-direction displacement S of the dummy chest xchest , calculate S xchest and S xref The difference between the values ​​of x ; The Y-direction acceleration curve collected by the third group of acceleration sensors is integrated twice with respect to time to obtain the Y-direction displacement S of the test seat reference point. yref ; The Y-direction acceleration curve collected by the second group of acceleration sensors is integrated twice with respect to time to obtain the Y-direction displacement S of the dummy chest ychest , calculate S ychest and S yref The difference between the two values ​​is used to obtain the Y-direction displacement ΔS of the dummy chest. y .

6. A frontal 25% offset collision slide test method based on dummy displacement according to claim 5, characterized in that: The S33 intercepts the motion trajectory curve of the dummy from the initial displacement to the maximum displacement in the X direction, and constructs a linear regression function reflecting the collision motion response of the dummy for the intercepted curve, and its expression is as follows: Y chest =a*x chest +b chest Among them, Y chest is the displacement of the dummy in the Y direction, a is the coefficient of the regression function, x chest is the displacement of the dummy in the X direction, b chest is the intercept of the regression function.

7. A frontal 25% offset collision slide test method based on dummy displacement according to claim 6, characterized in that: In S34, the initial deflection angle θ of the front 25% offset collision slide test is obtained by using an inverse trigonometric function, as shown in the following formula: θ=arctan(a) Among them, θ is the initial deflection angle of the collision slide test section, and a is the slope of the regression function constructed by S33.

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