Tailgate motion envelope production method and system

Abstract

The present invention discloses a method and system for making a tailgate motion envelope. The method comprises the steps of establishing a simulation model, simulating the motion of a target vehicle's tailgate under multiple working conditions; simulating and obtaining the extreme position of the tailgate under each working condition; establishing an extreme digital model that maximizes the target vehicle's tailgate entity; sweeping the extreme digital model according to the extreme position of the tailgate under each working condition to obtain the tailgate motion sub-envelope under the corresponding working condition; and combining the tailgate motion sub-envelopes under each working condition to obtain the tailgate motion envelope. By establishing a motion envelope for the target vehicle's entity's maximum extreme digital model, it is possible to ensure that the design clearance between the vehicle's tailgate motion envelope and the surrounding parts is reasonable in the early stage of vehicle design, thereby preventing the problem of interference between the tailgate and the surrounding parts in the later stage, which leads to an increase in cost and time.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle tailgate design, and in particular to a method and system for producing a tailgate motion envelope. Background Art

[0002] The motion envelope of a vehicle's tailgate refers to the motion space occupied by the vehicle's tailgate when it moves, vibrates, and twists to various extreme positions under various operating conditions. In the past, during the design and development of vehicle tailgates, actual working conditions were not considered, and only empirical design was used to ensure the static clearance between the vehicle's tailgate and surrounding parts. Actual vehicle tailgates often deviate from their original positions due to vibration and twisting, resulting in interference problems, which required repeated modifications of the design, mold adjustments, or even mold redoing to solve, increasing a lot of time and development costs. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for producing a tailgate motion envelope, which can produce the motion envelope of a vehicle tailgate during the automobile design and development stage, verify whether the gap surface difference between the tailgate and surrounding components is reasonable, avoid interference between the actual vehicle tailgate and surrounding components during movement, and reduce the cost of later modifications.

[0004] In order to solve the above technical problems, the present invention provides a method for producing a tailgate motion envelope, comprising the following steps:

[0005] Step 1: Establish a simulation model to simulate the movement of the tailgate of the target vehicle under multiple working conditions;

[0006] Step 2: Simulate and obtain the extreme position of the tailgate under various working conditions;

[0007] Step 3: Establish a limit digital model that maximizes the tailgate entity of the target vehicle;

[0008] Step 4: According to the extreme position of the tailgate under each working condition, sweep the extreme digital model to obtain the tailgate motion sub-envelope under the corresponding working condition;

[0009] Step 5: Combine the tailgate motion sub-envelopes under various working conditions to obtain the tailgate motion envelope.

[0010] In the above-mentioned tailgate motion envelope production method, the motion envelope is established by the physical maximum limit digital model of the target vehicle, so that the design gap between the vehicle tailgate motion envelope and the surrounding parts can be ensured to be reasonable in the early stage of vehicle design, thereby preventing the problem of interference between the tailgate and the surrounding parts in the later stage, which will lead to increased costs and time.

[0011] As an improvement of the method for making the tailgate motion envelope of the present invention, the working condition includes a pit working condition. In step 4, obtaining the tailgate motion envelope under the pit working condition includes:

[0012] Step a1: obtaining the left limit position of the tailgate simulation movement under the pit condition;

[0013] Step a2: Calculate the first displacement of the tailgate when it simulates movement to the left extreme position;

[0014] Step a3: correcting the first displacement to obtain a first corrected displacement;

[0015] Step a4: Sweeping the limit digital model of the tailgate of the target vehicle by a first correction displacement to obtain a first envelope;

[0016] Step a5: Mirror the first envelope with respect to the Y reference plane of the target vehicle to obtain a second envelope;

[0017] Step a6: Combine the first envelope and the second envelope to obtain a motion sub-envelope of the tailgate of the target vehicle under the pothole condition.

[0018] The left extreme position of the pit working condition is obtained through simulation and corrected. The sweep path and parameters are determined according to the left extreme position to obtain the left motion envelope of the target vehicle tailgate. The right motion envelope is then obtained by mirroring. The two are combined to obtain the motion sub-envelope under the pit working condition. The whole acquisition process is efficient and fast, and the simulation calculation is accurate and reliable.

[0019] Furthermore, before step a3, the method further includes: obtaining a correction coefficient between the simulation analysis and the actual vehicle test under the pothole condition, wherein the obtaining method includes the following steps:

[0020] Step b1: simulating and obtaining the left extreme position of the tailgate of different models of vehicles under the pit working condition;

[0021] Step b2: Calculate the simulated first displacement of the tailgate of different models of vehicles when it moves to the corresponding left extreme position, set as s1, s2…s n ;

[0022] Step b3: obtaining the left extreme position of the tailgate of different models of vehicles under the pit condition through actual vehicle testing;

[0023] Step b4: Calculate the actual first displacement of the tailgate of different models of vehicles when it moves to the corresponding left limit position, set as P1, P2...P n ;

[0024] Step b5: Calculate the correction coefficient through the simulated first displacement and actual first displacement of different vehicle models. Suppose the correction coefficient is μ, then:

[0025]

[0026] Furthermore, the first displacement is corrected to obtain a first corrected displacement. Optionally, the correction coefficient is multiplied by the simulated first displacement to obtain the first corrected displacement, that is,

[0027] P = μ * S;

[0028] Wherein, P is the first corrected displacement, and S is the simulated first displacement.

[0029] In order to solve the above technical problems, the present invention further provides a tailgate motion envelope production system, comprising:

[0030] The first building module: building a simulation model to simulate the movement of the tailgate of the target vehicle under multiple working conditions;

[0031] Simulation module: simulate and obtain the extreme position of the tailgate under various working conditions;

[0032] The second building module: building a limit digital model that maximizes the tailgate entity of the target vehicle;

[0033] Sweep module: According to the extreme position of the tailgate under various working conditions, the extreme digital model is swept to obtain the tailgate motion sub-envelope under the corresponding working conditions;

[0034] Combination module: The tailgate motion envelope is obtained by combining the tailgate motion sub-envelopes under various working conditions.

[0035] In order to solve the above technical problems, the present invention also provides a tailgate design method, which adopts the above method to obtain the motion envelope of the vehicle tailgate, and designs the gap of the tailgate according to the motion envelope to ensure that the design gap between the motion envelope of the vehicle tailgate and the surrounding parts is reasonable, so as to prevent the problem of interference between the tailgate and the surrounding parts in the later stage, which will lead to increased cost and time.

[0036] In summary, the above-mentioned tailgate motion envelope production method and system can be used to produce the motion envelope of the vehicle tailgate during the automobile design and development stage, verify whether the gap surface difference between the tailgate and surrounding components is reasonable, avoid interference between the actual vehicle tailgate and surrounding components during movement, and reduce the cost of later modifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the attached picture:

[0038] Figure 1 It is a flow chart of the method for making the tailgate motion envelope of the present invention.

[0039] Figure 2 It is a structural block diagram of the tailgate motion envelope making system of the present invention. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0041] Example 1

[0042] The description of up, down, left, and right directions in this context is based on the orientation of the vehicle. The up and down directions are the Z direction of the vehicle, that is, the vertical direction; the left and right directions are the Y direction of the vehicle, that is, the lateral direction; the front and back directions are the X direction of the vehicle, that is, the longitudinal direction, and the front is the positive direction of X. The vehicle Y reference plane is the left-right symmetric plane of the vehicle.

[0043] Sweep: The trajectory of an object moving along a certain path is called a sweep. In the present invention, the sweep of the tailgate is to translate or rotate the tailgate. During this process, the space of the area through which the tailgate moves forms the motion envelope of the tailgate.

[0044] like Figure 1 As shown, a method for making a tailgate motion envelope of the present invention comprises the following steps:

[0045] Step S10: Establish a simulation model to simulate the movement of the tailgate of the target vehicle under multiple working conditions, wherein the working conditions include: a pit working condition, a tailgate closing working condition, and a tailgate opening working condition. Establish a simulated road surface for the pit working condition and a whole vehicle simulation model to simulate the movement of the tailgate when the vehicle passes through a pit, and to simulate the opening and closing of the tailgate. Example of a pit working condition: When a vehicle passes through a pit with a size of b on the left side of the vehicle at a speed of a km / h, obtain the left extreme position.

[0046] Step S20: Simulate and obtain the extreme positions of the tailgate under various working conditions. There are four extreme positions: Under the pit working condition, the movement of the tailgate is mainly in the lateral direction of the vehicle, that is, it has two values: the left extreme position and the right extreme position. Under the closed working condition, the movement of the tailgate through the gate is considered, that is, the lower extreme position of the tailgate rotating downward. Under the open working condition, the movement of the tailgate rotating upward is considered, that is, the upper extreme position.

[0047] Step S30: Establishing the limit digital model that maximizes the tailgate entity of the target vehicle. In order to ensure that the envelope formed by the final sweep can cover all tailgate sizes more accurately, the worst case of overall tailgate surface difference and gap is taken to maximize the tailgate entity. Specifically including:

[0048] (1) Build a three-dimensional digital model of the tailgate of the target vehicle. Collect the three-dimensional data of all the parts on the tailgate, and use the three-dimensional modeling software to build a three-dimensional digital model of the tailgate. The digital model includes all the tailgate parts such as the tailgate sheet metal, taillights, tailgate interior panels, hinges, tailgate locks, sealing strips, spoilers, bright strips, buffer blocks, etc. Optionally, when modeling, each part is modeled with basic dimensions without considering dimensional tolerances. In addition, the three-dimensional modeling software can be CATIA, and all tailgate parts are three-dimensional digital model files in CATIA format.

[0049] (2) Based on the three-dimensional digital model, according to the clearance and face difference requirements of the tailgate, the maximum limit digital model of the tailgate entity is produced. Usually, the tailgate is divided into four parts: the upper top surface, the lower back surface, the left side surface and the right side surface. According to the clearance and face difference requirements of the four parts of the tailgate, the digital models of each part of the tailgate are swept according to the maximum clearance and face difference. Then, all the sweeping trajectories of the tailgate are combined to obtain the maximum limit digital model of the tailgate entity.

[0050] For example: the defined clearance requirement for the left side of the tailgate is 4.5±1.5mm and the face difference requirement is 0±1mm. The three-dimensional digital model of the left side obtained in step S10 is translated and swept by -1.5mm along the clearance direction and then translated and swept by -1mm along the face difference direction (note that the envelope obtained by the translational sweep along the clearance direction is translated and swept along the face difference direction as a whole). The sweeping trajectory is the extreme digital model of the left side of the tailgate. Similarly, the extreme digital models of the four parts of the tailgate can be obtained, and the combination of them is the extreme digital model of the tailgate.

[0051] Optionally, step S35: extract the outer surface of the tailgate limit digital model. Use the extraction command in the 3D software to extract the outer surface to obtain the maximum solid outer surface of the tailgate. In the subsequent simulation and sweeping process, the maximum solid outer surface can be used to replace the limit digital model to simplify data calculation and improve efficiency.

[0052] Step S40: According to the extreme position of the tailgate under various working conditions, the extreme digital model is swept to obtain the tailgate motion envelope under the corresponding working condition. During the use of the tailgate, vibrations will occur and deviate from the preset position. The working condition with more serious deviation is the pit condition, that is, when the vehicle wheels pass through the pit, the vehicle body suddenly tilts and recovers. The working condition with more frequent occurrence is opening and closing the door, so the tailgate motion envelope under these three working conditions is mainly analyzed. Specifically:

[0053] (1) Obtaining the tailgate motion sub-envelope of the target vehicle under the pit condition includes:

[0054] Step a1: Obtain the left limit position of the tailgate simulation movement under the pit condition. The left limit position can be directly extracted in step S2.

[0055] Step a2: Calculate the first displacement of the tailgate simulation movement to the left extreme position. The tailgate movement under the pit condition can be approximately considered as left-right translation, and the first displacement is generally a linear displacement.

[0056] Step a2.5: Obtain the correction coefficient between the simulation analysis and the actual vehicle test under the pothole condition. Since the simulation accuracy of the pothole condition is low, the correction coefficient is added to correct the simulation result. The correction coefficient acquisition method includes the following steps:

[0057] Step b1: Simulate and obtain the left extreme position of the tailgate of different models of vehicles under the pit working condition. Similar to the simulation process of the target vehicle, a simulation model of different models of vehicles is established, the pit working condition is simulated and run, and simulation analysis is performed according to the pit working condition to obtain the left extreme position of the tailgate of different models of vehicles.

[0058] Step b2: Calculate the simulated first displacement of the tailgate of different models of vehicles when it moves to the corresponding left extreme position, set as s1, s2…s n .

[0059] Step b3: Real vehicle test to obtain the left extreme position of the tailgate of different models of vehicles under the pit condition. In the test site, the left extreme position of the tailgate of different models of vehicles when passing the pit is actually collected by driving the real vehicle through the pit condition.

[0060] Step b4: Calculate the actual first displacement of the tailgate of different models of vehicles when it moves to the corresponding left limit position, set as P1, P2...P n .

[0061] Step b5: Calculate the correction coefficient by using the simulated first displacement and the actual first displacement of different models of vehicles. Optionally, the correction coefficient is obtained by dividing the accumulated sum of the actual first displacements of different models of vehicles by the accumulated sum of the simulated first displacements. Suppose the correction coefficient is μ, then:

[0062]

[0063] Step a3: Correct the first displacement to obtain a first corrected displacement. Optionally, the correction coefficient is multiplied by the simulated first displacement to obtain the first corrected displacement, that is,

[0064] P = μ * S;

[0065] Wherein, P is the first corrected displacement, and S is the simulated first displacement.

[0066] Step a4: Sweep the limit digital model of the tailgate of the target vehicle with a first correction displacement to obtain a first envelope.

[0067] Step a5: Mirror the first envelope with the Y reference plane of the target vehicle to obtain the second envelope. Since the vehicle and the tailgate are mostly bilaterally symmetrical structures, the right envelope can be obtained directly in the radial direction. Optionally, the right envelope can also be obtained using the above steps a10-a40.

[0068] Step a6: Combine the first envelope and the second envelope to obtain a motion sub-envelope of the tailgate of the target vehicle under the pothole condition.

[0069] (2) Obtaining the tailgate motion sub-envelope of the target vehicle under the closing condition includes:

[0070] Step d1: Obtain the lower limit position of the tailgate simulation movement under the closing condition, which is directly obtained in step S20.

[0071] Step d2: Calculate the second displacement of the tailgate simulation movement to the lower limit position. Since the closing movement of the tailgate is a rotation axis rotating around the hinge, the second displacement is generally a rotation arc, but since the arc size is small and in order to simplify the calculation, the height of the tailgate lowered in the vertical direction can be used as the second displacement.

[0072] Step d3: Calculate the tailgate over-rotation angle according to the second displacement. Assume that the second displacement is i and the over-rotation angle is θ, then,

[0073]

[0074] Where r is the distance from the center of the hinge axis to the lowest point on the lower back of the tailgate.

[0075] Step d4: Determine the limit position of the hinge axis. The hinge has tolerances on the mounting surface, which causes the hinge axis to deviate. The farther the axis is from the tailgate, the larger the tailgate motion envelope will be when it is closed, which is representative. Therefore, the limit position is taken for subsequent work.

[0076] In addition, since the hinge mounting hole is a through hole, it can be adjusted in the X and Y directions, of which the Y direction has little effect on the closing condition envelope, and the deviation in the Z direction will not be large, so only the tolerance size of X needs to be considered. Optionally, according to the tolerance size of the hinge shaft in the X direction, the X-direction limit position of the tailgate hinge shaft in front of the target vehicle is determined, and the X-direction limit position is used as the sweep axis.

[0077] Step d5: The limit digital model of the tailgate of the target vehicle is rotated and swept through the rotation angle with the hinge axis at the limit position as the rotation axis to obtain the motion sub-envelope of the tailgate of the target vehicle under the door closing condition.

[0078] (3) Obtaining the tailgate motion sub-envelope under the target vehicle opening condition includes:

[0079] Determine the X-axis limit position of the tailgate hinge axis in front of the target vehicle;

[0080] The extreme digital model of the tailgate of the target vehicle is rotated and swept at a set angle with the hinge axis at the extreme position in the X direction as the axis to obtain the motion sub-envelope of the tailgate of the target vehicle under the opening condition, where the set angle is the sum of the opening design angle and the over-opening design angle.

[0081] When designing the tailgate, there is a limit on the over-opening position, and the over-opening angle is a design parameter. Generally, the tailgate opening design angle is 90°, and the over-opening angle is 5°. Therefore, the motion envelope of the opening condition can be studied by studying the upper limit position of the simulation results, or it can be directly obtained by sweeping with a set angle.

[0082] Step S50: combining the tailgate motion sub-envelopes under various working conditions to obtain the tailgate motion envelope.

[0083] like Figure 2 As shown, the present invention provides a system based on the above tailgate motion envelope production method, comprising: a first establishment module: establishing a simulation model to simulate the motion of the tailgate of a target vehicle under multiple working conditions;

[0084] Simulation module: simulate and obtain the extreme position of the tailgate under various working conditions;

[0085] The second building module: building a limit digital model that maximizes the tailgate entity of the target vehicle;

[0086] Sweep module: According to the extreme position of the tailgate under various working conditions, the extreme digital model is swept to obtain the tailgate motion sub-envelope under the corresponding working conditions;

[0087] Combination module: The tailgate motion envelope is obtained by combining the tailgate motion sub-envelopes under various working conditions.

[0088] Each module in the system has the same working method as described above.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A method for producing a tailgate motion envelope, characterized in that: The steps include: Step 1: Establish a simulation model to simulate the movement of the tailgate of the target vehicle under multiple working conditions; Step 2: Simulate and obtain the extreme position of the tailgate under various working conditions; Step 3: Establish a limit digital model that maximizes the tailgate entity of the target vehicle; Step 4: According to the extreme position of the tailgate under each working condition, sweep the extreme digital model to obtain the tailgate motion sub-envelope under the corresponding working condition; Step 5: Combining the tailgate motion sub-envelopes under various working conditions to obtain the tailgate motion envelope; Among them, the working conditions include: pit working condition, tailgate closing working condition and tailgate opening working condition; there are four extreme positions: in the pit working condition, the movement of the tailgate is mainly in the lateral direction of the vehicle, that is, it has two values ​​of the left extreme position and the right extreme position; in the closing working condition, the movement of the tailgate passing through is considered, that is, the lower extreme position of the tailgate rotating downward; in the opening working condition, the movement of the tailgate rotating upward is considered, that is, the upper extreme position; In step 4, obtaining the tailgate motion envelope under the pit condition includes: Step a1: obtaining the left limit position of the tailgate simulation movement under the pit condition; Step a2: Calculate the first displacement of the tailgate when it simulates movement to the left extreme position; Step a3: correcting the first displacement to obtain a first corrected displacement; Step a4: Sweeping the limit digital model of the tailgate of the target vehicle by a first correction displacement to obtain a first envelope; Step a5: Mirror the first envelope with respect to the Y reference plane of the target vehicle to obtain a second envelope; Step a6: Combine the first envelope and the second envelope to obtain a motion sub-envelope of the tailgate of the target vehicle under the pothole condition.

2. The method for producing a tailgate motion envelope according to claim 1, characterized in that: Before step a3, the method further includes: obtaining a correction coefficient between the simulation analysis and the actual vehicle test under the pothole condition, wherein the obtaining method includes the following steps: Step b1: simulating and obtaining the left extreme position of the tailgate of different models of vehicles under the pit working condition; Step b2: Calculate the simulated first displacement of the tailgate of different models of vehicles when the tailgate moves to the corresponding left extreme position; Step b3: obtaining the left extreme position of the tailgate of different models of vehicles under the pit condition through actual vehicle testing; Step b4: Calculate the actual first displacement of the tailgate of different models of vehicles when it actually moves to the corresponding left extreme position; Step b5: Calculate the correction coefficient through the simulated first displacement and the actual first displacement of different models of vehicles.

3. The method for producing a tailgate motion envelope according to claim 2, characterized in that: The step b5 comprises: The correction coefficient is obtained by dividing the accumulated sum of the actual first displacements of different models of vehicles by the accumulated sum of the simulated first displacements.

4. A method for producing a tailgate motion envelope according to claim 2 or 3, characterized in that: The step a3 comprises: The correction coefficient is multiplied by the simulated first displacement to obtain the first corrected displacement.

5. The method for producing a tailgate motion envelope according to claim 1, characterized in that: The working condition includes a closing working condition. In step 4, obtaining the tailgate motion envelope under the closing working condition includes: Step d1: obtaining the lower limit position of the tailgate simulation movement under the closing condition; Step d2: calculating the second displacement of the tailgate when it simulates movement to the lower limit position; Step d3: calculating the tailgate over-rotation angle according to the second displacement; Step d4: determining the limit position of the hinge axis; Step d5: The limit digital model of the tailgate of the target vehicle is rotated and swept through the rotation angle with the hinge axis at the limit position as the rotation axis to obtain the motion sub-envelope of the tailgate of the target vehicle under the door closing condition.

6. The method for producing a tailgate motion envelope according to claim 5, characterized in that: In step d4: according to the tolerance dimension of the hinge shaft in the X direction, the X-direction limit position of the tailgate hinge shaft in front of the target vehicle is determined.

7. The method for producing a tailgate motion envelope according to claim 1, characterized in that: The working condition includes an opening working condition. In step 4, obtaining the tailgate motion envelope under the opening working condition includes: Determine the X-axis limit position of the tailgate hinge axis in front of the target vehicle; The extreme digital model of the tailgate of the target vehicle is rotated and swept at a set angle with the hinge axis at the extreme position in the X direction as the axis to obtain the motion sub-envelope of the tailgate of the target vehicle under the opening condition, where the set angle is the sum of the opening design angle and the over-opening design angle.

8. The method for producing a tailgate motion envelope according to claim 1, characterized in that: The step three comprises: Build a 3D digital model of the target vehicle's tailgate; Based on the three-dimensional digital model and in accordance with the clearance and flushness requirements of the tailgate, a maximum limit digital model of the tailgate entity is established.

9. A tailgate motion envelope making system based on the tailgate motion envelope making method according to any one of claims 1 to 8, characterized in that: include: The first building module: building a simulation model to simulate the movement of the tailgate of the target vehicle under multiple working conditions; Simulation module: simulate and obtain the extreme position of the tailgate under various working conditions; The second building module: building a limit digital model that maximizes the tailgate entity of the target vehicle; Sweep module: According to the extreme position of the tailgate under various working conditions, the extreme digital model is swept to obtain the tailgate motion sub-envelope under the corresponding working conditions; Combination module: The tailgate motion envelope is obtained by combining the tailgate motion sub-envelopes under various working conditions.

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