A load decomposition method and device

Abstract

The present application discloses a load decomposition method and device, including: establishing a multi-body model of a bus suspension. Selecting a jump-side wheel from the wheels in the multi-body model of the bus suspension, and applying an upward input vertical load at the ground contact point of the jump-side wheel. Selecting a non-jump-side wheel corresponding to the jump-side wheel, and obtaining a target correction load for the non-jump-side wheel according to the non-jump-side static condition, wherein the value of the target correction load is greater than the static load. Applying an upward target correction load at the ground contact point of the non-jump-side wheel. Based on the multi-body model of the bus suspension, static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-direction force loads at the hard points where the bus suspension and the body are connected. The loads at the hard points where the vehicle suspension and the body are connected extracted by the present application are more accurate and consistent with the actual driving conditions of the bus.

Description

Technical Field

[0001] The present application relates to the field of computer-aided design, and in particular to a load decomposition method and device. Background Art

[0002] Load decomposition technology is a computer virtual iteration technology based on multi-body dynamics models. Using this technology, based on the established multi-body dynamics model of the vehicle, the loads of the connection hard points of each component of the vehicle are extracted through software simulation. The extracted loads can be used for subsequent strength and fatigue simulation analysis of each component of the vehicle.

[0003] At present, in many vehicle working conditions, such as wheel jump conditions, the load decomposition method for the hard points connecting the bus suspension and the body adopts inertial load to realize load extraction. However, the load decomposition method using inertial load to extract the load at the hard points connecting the vehicle suspension and the body is not accurate enough and cannot truly reflect the stress conditions at the hard points connecting the vehicle suspension and the body under various working conditions. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a load decomposition method and device for realizing load extraction at the hard points of connection between vehicle suspension and vehicle body under wheel jumping conditions, and the extracted load is more accurate.

[0005] In order to achieve the above purpose, the technical solutions provided by the embodiments of the present application are as follows:

[0006] The present application provides a load decomposition method, the method comprising:

[0007] Establish a multi-body model of bus suspension;

[0008] Selecting an upward-jumping-side wheel from the wheels in the passenger car suspension multi-body model, and applying an upward input vertical load to a ground contact point of the upward-jumping-side wheel;

[0009] A non-jumping side wheel corresponding to the jumping side wheel is selected, and a target correction load of the non-jumping side wheel is obtained according to a non-jumping side static condition; the value of the target correction load is greater than the static load;

[0010] Applying the target correction load in an upward direction to the contact point of the non-jumping side wheel;

[0011] Based on the bus suspension multi-body model, static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-axis force loads of the connection hard points between the bus suspension and the body.

[0012] Optionally, obtaining the target corrected load of the wheel on the non-jumping side according to the stationary condition of the non-jumping side includes:

[0013] Obtaining an initial value of the corrected load of the non-jumping side wheel;

[0014] Based on the bus suspension multi-body model, an iterative static load simulation is performed using the input vertical load, the initial value of the correction load and the non-jumping side static condition to obtain a target correction load for the non-jumping side wheel.

[0015] Optionally, the obtaining of the initial value of the corrected load of the non-jumping side wheel includes:

[0016] Calculate the anti-roll force of stabilizer bar bushings in passenger car suspensions;

[0017] The initial value of the corrected load is calculated based on the stabilizer bar bushing anti-roll force, the input vertical load, the axle load, the wheelbase, the distance from the stabilizer bar body end bushing to the body centerline, the distance from the body center of mass to the centerline and the stabilizer bar roll angle using the moment balance principle.

[0018] Optionally, the iterative static load simulation is performed based on the bus suspension multi-body model using the input vertical load, the initial value of the modified load and the static condition of the non-jumping side to obtain the target modified load of the wheel on the non-jumping side, including:

[0019] Applying the correction load required for this iteration in an upward direction at the contact point of the non-jumping side wheel; when the correction load is applied for the first time, the value of the correction load is the initial value of the correction load;

[0020] Based on the bus suspension multi-body model, static load simulation is performed using the applied input vertical load and the correction load required for this iteration to obtain displacement information of the non-jumping side wheel;

[0021] Determining whether the displacement information is within a preset range;

[0022] If so, determine the correction load required for this iteration as the target correction load;

[0023] If not, use the correction load required for this iteration to obtain an updated correction load, and use the updated correction load as the correction load required for the next iteration; repeat the steps of applying the correction load required for this iteration upward at the contact point of the non-jumping side wheel and subsequent steps until the displacement information is within the preset range, and determine that the correction load required for this iteration is the target correction load.

[0024] Optionally, the establishing of the bus suspension multi-body model includes: establishing an airbag spring model;

[0025] The method of establishing the airbag spring model comprises:

[0026] Acquire an airbag multi-pressure stiffness curve; the airbag multi-pressure stiffness curve is generated based on test data; the test data is obtained by setting a preset number of test pressure values ​​and performing a compression test on the airbag spring under the preset number of test pressure values; the test data includes a test applied force and a compression amount of the airbag spring;

[0027] Based on the airbag multi-pressure stiffness curve and the actual air pressure of the environment where the airbag spring is located, using a linear interpolation method to obtain an actual stiffness curve of the airbag spring;

[0028] An airbag spring model is established based on the actual stiffness curve of the airbag spring.

[0029] The present application also provides a load decomposition device, the device comprising:

[0030] Model building unit, used to build a multi-body model of bus suspension;

[0031] An input vertical load applying unit is used to select an upward jumping side wheel from the wheels in the passenger car suspension multi-body model, and apply an upward input vertical load to the ground contact point of the upward jumping side wheel;

[0032] A first acquisition unit is used to select a non-jumping side wheel corresponding to the jumping side wheel, and acquire a target correction load of the non-jumping side wheel according to a non-jumping side static condition; the value of the target correction load is greater than the static load;

[0033] A target correction load applying unit, used for applying the target correction load in an upward direction to the contact point of the non-jumping side wheel;

[0034] The second acquisition unit is used to perform static load simulation based on the bus suspension multi-body model and use the applied input vertical load and the target correction load to obtain the six-axis force load of the connection hard point between the bus suspension and the body.

[0035] Optionally, the first acquiring unit includes:

[0036] A first acquisition subunit is used to acquire an initial value of the corrected load of the non-jumping side wheel;

[0037] The second acquisition subunit is used to perform iterative static load simulation based on the bus suspension multi-body model, using the input vertical load, the initial value of the correction load and the non-jumping side static condition to obtain the target correction load of the non-jumping side wheel.

[0038] Optionally, the first acquiring subunit includes:

[0039] A first calculation subunit is used to calculate the anti-roll force of the stabilizer bar bushing in the passenger car suspension;

[0040] The second calculation subunit is used to calculate the initial value of the corrected load based on the stabilizer bar bushing anti-roll force, the input vertical load, the axle load, the wheelbase, the distance from the stabilizer bar body end bushing to the body centerline, the distance from the body center of mass to the centerline and the stabilizer bar roll angle using the moment balance principle.

[0041] Optionally, the second acquiring subunit includes:

[0042] A correction load applying subunit is used to apply the correction load required for this iteration in an upward direction at the contact point of the non-jumping side wheel; when the correction load is applied for the first time, the value of the correction load is the initial value of the correction load;

[0043] A third acquisition subunit is used to perform static load simulation based on the bus suspension multi-body model, using the applied input vertical load and the correction load required for this iteration, to obtain the displacement information of the non-jumping side wheel;

[0044] A judging subunit, used to judge whether the displacement information is within a preset range;

[0045] a determination subunit, configured to determine the correction load required for this iteration as a target correction load when the judgment result of the judgment subunit is that the displacement information is within a preset range;

[0046] The correction load updating subunit is used to obtain an updated correction load using the correction load required for this iteration when the displacement information is not within the preset range, and use the updated correction load as the correction load required for the next iteration; repeatedly execute the correction load required for this iteration and subsequent steps of applying the correction load required for this iteration upward at the contact point of the non-jumping side wheel until the displacement information is within the preset range, and determine that the correction load required for this iteration is the target correction load.

[0047] Optionally, the model building unit includes: an airbag spring model building subunit, used to build an airbag spring model;

[0048] The airbag spring model establishment subunit includes:

[0049] a fourth acquisition subunit, configured to acquire a multi-pressure stiffness curve of an airbag; the multi-pressure stiffness curve of the airbag is generated based on test data; the test data is acquired by setting a preset number of test pressure values ​​and performing a compression test on the airbag spring under the preset number of test pressure values; the test data includes a test applied force and a compression amount of the airbag spring;

[0050] a fifth acquisition subunit, configured to acquire an actual stiffness curve of the airbag spring by using a linear interpolation method based on the airbag multi-pressure stiffness curve and the actual air pressure of the environment where the airbag spring is located;

[0051] A subunit is established for establishing an airbag spring model based on an actual stiffness curve of the airbag spring.

[0052] Through the above technical solution, it can be seen that the present application has the following beneficial effects:

[0053] The embodiment of the present application provides a load decomposition method and device, the method comprising: establishing a multi-body model of a bus suspension. Selecting a wheel on the jumping side from the wheels in the multi-body model of the bus suspension, and applying an input vertical load in an upward direction to the ground contact point of the wheel on the jumping side. Selecting a non-jumping side wheel corresponding to the wheel on the jumping side, and obtaining a target correction load for the wheel on the non-jumping side according to the static condition of the non-jumping side, wherein the value of the target correction load is greater than the static load. Applying an upward target correction load to the ground contact point of the wheel on the non-jumping side. Based on the multi-body model of the bus suspension, a static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-direction force loads of the hard points connecting the bus suspension and the body. In the embodiment of the present application, the actual wheel jumping condition of the vehicle is simulated, and an upward road load is applied to the ground contact point of the wheel on the jumping side of the multi-body model of the bus suspension, which essentially replaces the inertia load commonly used in the prior art with a road load. In addition, when applying road loads, considering that the bus suspension is a non-independent suspension, in order to make the force on the non-jumping side wheel in the bus suspension multi-body model consistent with the force on the non-jumping side wheel under the actual wheel jumping condition, and thus make the final extracted load at the hard point where the vehicle suspension and the body are connected more accurate, the target correction load in the upward direction is applied to the grounding point of the non-jumping side wheel to correct the force on the non-jumping side wheel. Finally, the load at the hard point where the vehicle suspension and the body are connected extracted by static load simulation based on the bus suspension multi-body model is more accurate and consistent with the actual driving condition of the bus. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1a A schematic diagram of the structure of a front suspension system for a passenger car provided in an embodiment of the present application;

[0056] Figure 1b A schematic diagram of the structure of a passenger car rear suspension system provided in an embodiment of the present application;

[0057] Figure 2 A flow chart of a load decomposition method provided in an embodiment of the present application;

[0058] Figure 3 A schematic diagram of a multi-pressure stiffness curve of an airbag provided in an embodiment of the present application;

[0059] Figure 4 A schematic diagram of loads applied to the wheels on the jumping side and the wheels on the non-jumping side provided in an embodiment of the present application;

[0060] Figure 5 A schematic diagram of six-direction force loads of a connection hard point of a suspension system provided in an embodiment of the present application;

[0061] Figure 6 A flow chart of a method for obtaining a target correction load of a non-jumping side wheel provided in an embodiment of the present application;

[0062] Figure 7 A schematic diagram of an initial value of a corrected load applied to a non-jumping wheel provided in an embodiment of the present application;

[0063] Figure 8 A schematic diagram of geometric parameters of a stabilizer bar provided in an embodiment of the present application;

[0064] Fig. 9 A schematic diagram of a load decomposition device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0066] In order to facilitate the understanding and explanation of the technical solution of the present application, the background technology of the embodiments of the present application is first introduced.

[0067] The bus suspension system includes the front suspension system and the rear suspension system. The bus can be modeled by using modeling and analysis software such as Adams Car, and then analyzed based on the established multi-body dynamics model. Figure 1a and Figure 1b , Figure 1a and Figure 1b The front suspension system and rear suspension system of the bus shown are both established front suspension system multi-body dynamics models and rear suspension system multi-body dynamics models. Among them, the front suspension system and rear suspension system of the bus both include a shock absorber 1, an air bag (also called an air bag spring) 2, a thrust rod and a stabilizer bar 4. The thrust rod includes a lateral thrust rod 31 and a longitudinal thrust rod 32.

[0068] Load decomposition technology is a computer virtual iteration technology based on multi-body dynamics models. Using this technology, based on the established multi-body dynamics model of the vehicle, the loads of the hard points connecting the various components of the vehicle are extracted through software simulation. The extracted loads can be used for subsequent strength and fatigue simulation analysis of various vehicle components. For example, the loads of the hard points connecting the components and the vehicle body in the front suspension system can be extracted based on the multi-body dynamics model of the front suspension system and load decomposition technology, and the same is true for the rear suspension system. Figure 1a and Figure 1b The shock absorber 1, the airbag 2, the lateral thrust rod 31, the longitudinal thrust rod 32 and the stabilizer bar 4 all have mounting points with the vehicle body, also known as connection hard points.

[0069] At present, the load decomposition method for the hard points connecting the suspension and the body of a bus uses inertial loads to extract loads. That is, in the multi-body dynamics model, inertial loads are applied to the vehicle, and finally the loads at the connection hard points are obtained. Among them, inertial loads are loads caused by the inertia of the object, such as gravitational acceleration, angular velocity and angular acceleration.

[0070] There are many vehicle working conditions for vehicles, such as bending conditions, one wheel hanging conditions, steering conditions, braking conditions, acceleration conditions and wheel jumping conditions. Under each working condition, the inertial load decomposition method needs to constrain the connection hard points. After the connection hard points are constrained, the stress of the constraint points calculated by the software is 0Mpa. For example, under each working condition, the displacement of the captured airbag upper plate connection hard points will be 0 due to the constraint, which will cause the displayed equivalent stress to be 0, while the load at the connection hard points is actually very large. Therefore, the load at the connection hard points of the airbag mounting plate obtained using the inertial load decomposition method cannot reflect the actual force condition of the airbag mounting plate. For another example, for other connection hard points, such as the connection hard points of the thrust rod, stabilizer bar and shock absorber, there is no load and no constraint, which is inconsistent with the actual situation. It can be seen that the inertial load decomposition method cannot truly reflect the actual stress at the connection hard points.

[0071] In addition, the inertial load decomposition method also has the problem of over-design. Inertial load is the inertial load field in the whole space. Since large-mass mounting parts are actually subject to large and significant inertial loads, it is very effective to use inertial loads to perform installation strength verification of local large-mass mounting parts (such as batteries) in the model. However, the inertial loads in other parts of the vehicle body are not significant in reality. If inertial loads are used for verification in the model, over-design will occur, resulting in failure to truly reflect the actual stress at the connection hard point and hindering the process of lightweighting and cost reduction and efficiency improvement.

[0072] In summary, the loads at the hard points where the vehicle suspension and body are connected extracted by the load decomposition method using inertial loads are not accurate enough and cannot truly reflect the stress conditions at the hard points where the vehicle suspension and body are connected under various working conditions.

[0073] Based on this, an embodiment of the present application provides a load decomposition method, including: establishing a multi-body model of a bus suspension. Selecting a wheel on the jumping side from the wheels in the multi-body model of the bus suspension, and applying an input vertical load in an upward direction to the ground contact point of the wheel on the jumping side. Selecting a non-jumping side wheel corresponding to the wheel on the jumping side, and obtaining a target correction load for the non-jumping side wheel; the value of the target correction load is greater than the static load. Applying an upward target correction load to the ground contact point of the non-jumping side wheel. Based on the multi-body model of the bus suspension, a static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-direction force loads of the hard points connecting the bus suspension and the body. In the embodiment of the present application, the actual wheel jumping condition of the vehicle is simulated, and an upward road load is applied to the ground contact point of the wheel on the jumping side of the multi-body model of the bus suspension. In essence, the road load is used instead of the inertia load commonly used in the prior art. In addition, when applying road loads, considering that the bus suspension is a non-independent suspension, in order to make the force on the non-jumping side wheel in the bus suspension multi-body model consistent with the force on the non-jumping side wheel under the actual wheel jumping condition, and thus make the final extracted load at the hard point where the vehicle suspension and the body are connected more accurate, the target correction load in the upward direction is applied to the grounding point of the non-jumping side wheel to correct the force on the non-jumping side wheel. Finally, the load at the hard point where the vehicle suspension and the body are connected extracted by static load simulation based on the bus suspension multi-body model is more accurate and consistent with the actual driving condition of the bus.

[0074] See also Figure 2 , Figure 2 The present invention provides a flow chart of a load decomposition method. The method can be applied to modeling and analysis software such as Adams Car. The method is used to extract the load at the hard point where the vehicle suspension and the vehicle body are connected when the vehicle is in a wheel jump condition. Figure 2 As shown, the method includes S201-S205:

[0075] S201: Establish a multi-body model of bus suspension.

[0076] The bus suspension system includes a front suspension system and a rear suspension system. Therefore, the bus suspension multibody model can be a front suspension multibody model and / or a rear suspension multibody model. Based on the established bus suspension multibody model, the load decomposition at the connection hard points in the subsequent suspension system is performed.

[0077] In practice, the load decomposition of the bus suspension system includes both the load decomposition of the front suspension system and the load decomposition of the rear suspension system. The load decomposition of the front suspension system and the load decomposition of the rear suspension system can be performed sequentially. The establishment process of the front suspension multibody model and the rear suspension multibody model are similar, and the load analysis process of the connection hard points on the front suspension system and the rear suspension system is similar. For simplicity, in the embodiment of the present application, the front suspension is used as an example for description.

[0078] The front suspension system and the rear suspension system of the bus both include a shock absorber 1, an airbag 2, a lateral thrust rod 31, a longitudinal thrust rod 32 and a stabilizer bar 4. In addition, the front suspension system also includes components such as a steering system and a bushing, and the rear suspension system also includes components such as a bushing. When establishing the front suspension system, according to the bus design data, the models of the various subsystems of the front suspension are first established, and then assembled into a multi-body model of the bus suspension. The various subsystems of the front suspension include one or more of a steering system, a shock absorber 1, an airbag 2, a lateral thrust rod 31, a longitudinal thrust rod 32, a bushing, a stabilizer bar 4, and a bridge housing. As an example, the multi-body model of the front suspension system is built using Adams Car software. Among them, considering its stiffness and large deformation, the bridge housing and the stabilizer bar 4 need to be made into flexible bodies in advance using optistruct software, and then referenced in the multi-body model.

[0079] When establishing the three-dimensional model of the airbag spring, it is necessary to input the stiffness curve of the airbag spring. The stiffness curve of the airbag spring is related to the air pressure of the compressed gas filled inside the airbag. Depending on the different design axle loads and the different vehicle operating conditions, the design initial air pressure of the airbag spring is often different. In the embodiment of the present application, establishing the multi-body model of the bus suspension includes establishing the airbag spring model.

[0080] Specifically, the airbag spring model is established, including:

[0081] Obtaining a multi-pressure stiffness curve of an airbag; the multi-pressure stiffness curve of an airbag is generated based on test data; the test data is obtained by setting a preset number of test pressure values ​​and performing a compression test on the airbag spring at the preset number of test pressure values; the test data includes a test applied force and a compression amount of the airbag spring;

[0082] Based on the multi-pressure stiffness curve of the airbag and the actual air pressure of the environment where the airbag spring is located, the actual stiffness curve of the airbag spring is obtained by using a linear interpolation method;

[0083] Based on the actual stiffness curve of the airbag spring, an airbag spring model is established.

[0084] Among them, the preset number of test air pressure values ​​can select the air pressure values ​​commonly used for airbags. For example, three test air pressure values ​​are set to 3bar, 5bar, and 6.5bar. Perform compression tests on the airbags respectively under the three air pressures, keep the airbags at equal volumes during the entire test process, and finally obtain the test data under the three air pressures. The test data includes the test applied force and the compression of the airbag spring. Using the test data, generate equal volume airbag stiffness curves under three air pressures with the airbag compression as the horizontal coordinate and the test applied force as the vertical coordinate. Figure 3 As shown, Figure 3 This is a schematic diagram of the multi-pressure stiffness curve of the airbag under three air pressures provided in the embodiment of the present application. Generally speaking, the higher the air pressure, the stronger the stiffness. Figure 3 The curves from top to bottom are the stiffness curves at 6.5 bar, 5 bar, and 3 bar.

[0085] Input the obtained airbag multi-pressure stiffness curve into the airbag spring model. When calling, input the actual air pressure of the environment where the airbag spring is located. When the input actual air pressure is different from the air pressure in the test, Adams Car software will perform linear interpolation based on the airbag multi-pressure stiffness curve to obtain the actual stiffness curve of the airbag spring under the actual air pressure, so as to improve the airbag spring model. For example, if the actual air pressure required is 4 bar, the stiffness curve under 4 bar can be obtained based on the stiffness curves under 5 bar and 3 bar and the linear difference method.

[0086] In the embodiment of the present application, the actual air pressure required by the airbag spring is directly input into software such as Adams Car to obtain a stiffness curve corresponding to the actual air pressure, thereby avoiding the problem of changing the actual air pressure required and having to re-create the airbag model file.

[0087] S202: Selecting a wheel on the upper jump side from the wheels in the bus suspension multi-body model, and applying an upward input vertical load to a ground contact point of the wheel on the upper jump side.

[0088] Since the embodiment of the present application is to extract the load at the hard point where the vehicle suspension and the vehicle body are connected under the wheel jump condition. After establishing the multi-body model of the passenger car suspension, taking the multi-body model of the front suspension system as an example, it is necessary to determine the jump-side wheel among the wheels. The wheel jump condition is a unilateral jump, that is, the other wheel of the same suspension system as the jump-side wheel is a non-jump-side wheel. It can be understood that the jump-side wheel simulates the jump-side wheel under the wheel jump condition. In order to simulate the actual situation, it is necessary to apply an input vertical load in an upward direction to the ground contact point of the jump-side wheel. Figure 4 This is a schematic diagram of the load applied to the upper jump side wheel and the non-up jump side wheel provided in the embodiment of the present application. Figure 4 As shown, the wheel on the jumping side is 51, and the wheel on the non-jumping side is 52.

[0089] The input vertical load in the upward direction applied at the contact point of the wheel on the upper jumping side can be determined according to the empirical value. For example, the input vertical load is F input =2.5g*0.5*F axle , F axle For the axle load.

[0090] S203: Select a non-jumping side wheel corresponding to the jumping side wheel, and obtain a target correction load of the non-jumping side wheel according to a non-jumping side static condition; the value of the target correction load is greater than the static load.

[0091] After determining the wheel on the jumping side among the wheels, it can be determined that the other wheel in the same suspension system as the wheel on the jumping side is the wheel on the non-jumping side. In an embodiment of the present application, the target correction load of the wheel on the non-jumping side is obtained according to the non-jumping side static condition. The target correction load is the load applied to the wheel on the non-jumping side, and the value of the target correction load is required to be greater than the static load. As an example, the non-jumping side static condition is that the displacement information of the wheel on the non-jumping side is within a preset range. Optionally, the displacement information of the wheel on the non-jumping side is the displacement of the wheel center.

[0092] It should be noted that if the vehicle suspension is an independent suspension, the load on the jump side wheel will not be transferred to the non-jump side wheel, and the load on the non-jump side wheel is only a static load, that is, a load under the wheel's deadweight. Based on the suspension multi-body model, when the non-jump side wheel is loaded, a 1g load is applied to the non-jump side wheel, and the 1g load is used to simulate the actual static load, i.e., the load caused by gravity. However, the suspension of the passenger car in the embodiment of the present application is a non-independent suspension, and after the jump side wheel is applied with an upward vertical load, the jump side wheel can transfer the load to the non-jump side, causing the non-jump side wheel to have a pressure to the ground in addition to the gravity load. In the embodiment of the present application, the load calculation method of the independent suspension cannot be used, otherwise it will cause the subsequent load decomposition calculation to not converge, and the actual situation cannot be truly reflected.

[0093] In the embodiment of the present application, under the wheel jump condition, unlike the independent suspension that applies a 1g load on the wheel on the non-jumping side, it is necessary to apply a target correction load F on the non-jumping side. modify It can be understood that the target correction load F modify It is used to simulate the load transmitted from the wheel on the upper jump side to the wheel on the non-up jump side through the bridge body. In order to simulate the static state of the wheel on the non-up jump side in reality, the target correction load F is obtained. modify In the process, F modify It needs to be adjusted continuously until the non-jumping side static condition is reached. As an example, the non-jumping side static condition is that the z-direction displacement of the wheel center of the non-jumping side wheel is 0 mm. modifyThe value is greater than the static load, that is, F modify ≥1g*0.5*F axle .

[0094] It should be noted that the target correction load F provided in the embodiment of the present application is modify It truly reflects the transmission effect of the rigid bridge in the non-independent suspension on the wheel loads between the two wheels, and can better reflect the tire stress conditions under the wheel jump condition of the bus during actual driving.

[0095] In specific implementation, the target correction load of the wheel on the non-jumping side is obtained according to the static condition of the non-jumping side, including:

[0096] Obtaining the initial value of the corrected load of the non-jumping side wheel;

[0097] Based on the bus suspension multi-body model, iterative static load simulation is performed by inputting vertical load, initial value of modified load and static condition of non-jumping side to obtain the target modified load of the wheel on the non-jumping side.

[0098] It should be noted that the initial value of the modified load on the non-jumping side wheel is F iteration_0 Corrected load F for the target modify The approximate value of F is obtained by calculation. modify As an example, the initial value of the modified load is calculated using the moment balance principle.

[0099] Get F iteration_0 Then, based on the bus suspension multi-body model, an iterative static load simulation is performed using the input vertical load of the wheel on the jumping side, the initial value of the correction load of the wheel on the non-jumping side, and the static condition of the non-jumping side to obtain the target correction load of the wheel on the non-jumping side. The detailed process of obtaining the target correction load of the wheel on the non-jumping side can be referred to the subsequent embodiments.

[0100] S204: Apply a target correction load in an upward direction to the contact point of the non-jumping side wheel.

[0101] It should be noted that the target correction load also belongs to the vertical load.

[0102] S205: Based on the bus suspension multi-body model, static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-axis force loads of the connection hard points between the bus suspension and the body.

[0103] After applying the input vertical load to the wheel on the jumping side and the target correction load to the wheel on the non-jumping side, a static load simulation is performed based on the bus suspension multi-body model to obtain the six-axis force loads on the hard points connecting the bus suspension and the body. Figure 5 , Figure 5 Schematic diagram of the six-direction force load of the connection hard point of the suspension system provided in the embodiment of the present application. Figure 5 As shown, the six-direction force loads Fx, Fy, Fz, Tx, Ty, Tz of the mounting point of the shock absorber 1, the mounting point of the airbag 2, the mounting point of the lateral thrust rod 31, the mounting point of the longitudinal thrust rod 32 and the mounting point of the stabilizer bar on the frame side are decomposed respectively. Among them, Fx, Fy, Fz are three force components, and Tx, Ty, Tz are three moment components. It can be understood that the applied input vertical load can be decomposed into three force components, which can be represented by Fx, Fy, Fz.

[0104] As an example, static load simulation is implemented by Adams Car software.

[0105] It should be noted that most of the existing bus failure cases are local failures, which often occur in the frame welds, that is, most of them are weld fatigue problems, and the bus industry mostly uses inertial loads, which cannot assess the strength of the sheet metal near the hard points of the frame. In addition, the bus industry also mostly uses Cweld rigid units to simulate the second-protection welds. The stress of the sheet metal units connected is relatively small, and the fatigue problem of the welds cannot be examined. In the embodiment of the present application, after obtaining the load of the connection hard point in the vehicle suspension system, the load of the connection hard point can be used to perform subsequent strength and fatigue simulation analysis of various vehicle components. For example, the load of the connection hard point can be used to effectively analyze the strength of sheet metal parts near the hard points of the frame, as well as the durability of the frame and body welds.

[0106] The embodiment of the present application provides a load decomposition method, which includes: establishing a multi-body model of a bus suspension. Selecting a wheel on the jumping side from the wheels in the multi-body model of the bus suspension, and applying an input vertical load in an upward direction to the ground contact point of the wheel on the jumping side. Selecting a non-jumping side wheel corresponding to the wheel on the jumping side, and obtaining a target correction load for the wheel on the non-jumping side according to the static condition of the non-jumping side, wherein the value of the target correction load is greater than the static load. Applying a target correction load in an upward direction to the ground contact point of the wheel on the non-jumping side. Based on the multi-body model of the bus suspension, a static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-direction force loads of the hard points connecting the bus suspension and the body. In the embodiment of the present application, the actual wheel jumping condition of the vehicle is simulated, and an upward road surface load is applied to the ground contact point of the wheel on the jumping side of the multi-body model of the bus suspension, which essentially replaces the inertia load commonly used in the prior art with a road surface load. In addition, when applying road loads, considering that the bus suspension is a non-independent suspension, in order to make the force on the non-jumping side wheel in the bus suspension multi-body model consistent with the force on the non-jumping side wheel under the actual wheel jumping condition, and thus make the final extracted load at the hard point where the vehicle suspension and the body are connected more accurate, the target correction load in the upward direction is applied to the grounding point of the non-jumping side wheel to correct the force on the non-jumping side wheel. Finally, the load at the hard point where the vehicle suspension and the body are connected extracted by static load simulation based on the bus suspension multi-body model is more accurate and consistent with the actual driving condition of the bus.

[0107] See also Figure 6 , Figure 6 A flow chart of a method for obtaining a target correction load of a non-jumping side wheel provided in an embodiment of the present application. Figure 6 As shown, in the above embodiment, based on the bus suspension multi-body model, iterative static load simulation is performed by inputting vertical load, initial value of modified load and static condition of non-jumping side to obtain target modified load of non-jumping side wheel, including S601-S606:

[0108] S601: Apply the correction load required for this iteration in an upward direction to the contact point of the wheel on the non-jumping side; when the correction load is applied for the first time, the value of the correction load is the initial value of the correction load.

[0109] Specifically, the correction load is F iteration_n , you need to first obtain the initial value of the corrected load, and then iteration_0 Iterate based on .

[0110] The initial value of the corrected load of the non-jumping side wheel is obtained, including:

[0111] Calculate the anti-roll force of stabilizer bar bushings in passenger car suspensions;

[0112] The initial value of the corrected load is calculated using the moment balance principle based on the stabilizer bar bushing anti-roll force, input vertical load, axle load, wheelbase, distance from the stabilizer bar body end bushing to the body centerline, distance from the body center of mass to the centerline and the stabilizer bar roll angle.

[0113] See also Figure 7 , Figure 7 This is a schematic diagram of the initial value of the modified load applied to the non-jumping wheel provided in the embodiment of the present application. Figure 7 As shown, the initial value F of the modified load is obtained by using the moment balance principle. iteration_0 The calculation formula is as follows:

[0114] F iteration_0 *L1=F input *L1+F axle *L3+F arb *L2

[0115] Solved:

[0116]

[0117] Among them: F input =2.5g*0.5*F axle is the input vertical load of the wheel on the jumping side; F axle is the axle load, in N. F arbis the anti-roll force of the stabilizer bar bushing, in N. L1 is 1 / 2 of the axle load, in mm. L2 is the distance from the stabilizer bar body end bushing to the body centerline, in mm. L3 is the distance from the body center of mass to the centerline, in mm.

[0118] It should be noted that, in addition to the anti-roll force F arb Except for , all other values ​​are the design values ​​of the vehicle and components, which are known quantities. arb The process is as follows:

[0119] Obtain the stabilizer bar roll angle and stabilizer bar roll stiffness in bus suspension;

[0120] Calculate the anti-roll force of the stabilizer bar bushing in a passenger car suspension based on the stabilizer bar roll angle and the stabilizer bar roll stiffness.

[0121] In practice, F arb The calculation formula is as follows:

[0122]

[0123] Where α is the stabilizer bar roll angle, in rad. is the roll stiffness of the stabilizer bar, in Nmm / rad. The calculation method is as follows:

[0124]

[0125] in, The parameters in the calculation formula can be found in Figure 8 , Figure 8 Schematic diagram of the geometric parameters of the stabilizer bar provided in the embodiment of the present application. Figure 8 As shown, A1 is a mounting point between the stabilizer bar and the axle, B1 is a point at the corner of the stabilizer bar arc, C1 is a mounting point between the stabilizer bar and the vehicle body, A2 is another mounting point between the stabilizer bar and the axle, B2 is another point at the corner of the stabilizer bar arc, and C2 is another mounting point between the stabilizer bar and the vehicle body. The horizontal direction of the stabilizer bar is the horizontal direction, that is, the straight line direction where C1C2 is located is the horizontal direction, and the direction perpendicular to the horizontal direction of the stabilizer bar is the longitudinal direction. L0 is the distance between C1 and C2, L 11 L is the lateral distance from A1 to A2. 22 is the longitudinal distance from A1 to C1, L 33 is the distance between B1 and B2, L4 is the lateral distance between A1 and B1, L5 is the lateral distance between A1 and C1, and L6 is the distance between A1 and B1. In addition, G is the torsional modulus of the stabilizer bar, I pis the polar moment of inertia of the stabilizer bar section, R is the radius of the arc at the corner of the stabilizer bar, θ is the angle between the straight line A2B2 and the horizontal direction of the stabilizer bar, E is the bending modulus of the stabilizer bar, and I is the moment of inertia of the stabilizer bar section. The outer diameter of the stabilizer bar is D, and the inner diameter is d.

[0126] S602: Based on the bus suspension multi-body model, static load simulation is performed using the applied input vertical load and the correction load required for this iteration to obtain the displacement information of the non-jumping side wheel.

[0127] Apply an upward vertical load F to the ground contact point of the wheel on the upper jump side. input =2.5g*0.5*F axle , apply an upward correction load F to the contact point of the non-jumping side wheel iteration_n , static load simulation is performed using software to obtain the displacement information of the non-jumping side wheel.

[0128] S603: Determine whether the displacement information is within a preset range.

[0129] It is determined whether the displacement information of the non-jumping side wheel is within a preset range. As an example, the displacement information is the wheel center displacement Dwc of the non-jumping side wheel, and the preset range is Dwc=0mm±0.2mm.

[0130] S604: If yes, determine that the correction load required for this iteration is the target correction load.

[0131] If so, determine the correction load required for this iteration as the target correction load, that is, F modify =F iteration_n . Where n is the number of iterations of this iteration.

[0132] S605: If not, obtain an updated correction load using the correction load required for this iteration, and use the updated correction load as the correction load required for the next iteration. Repeat S601 and subsequent steps until the displacement information is within the preset range, and determine that the correction load required for this iteration is the target correction load.

[0133] If not, the correction load needs to be updated.

[0134] Specifically, according to formula F iteration_n+1 =F iteration_n ±0.1*(F iteration_n ) obtains the updated corrected load, that is, the corrected load F required for the next iteration iteration_n+1 The modified load F required for this iteration iteration_n Calculated.

[0135] By using the method for obtaining the target correction load applied to the non-jumping wheel provided in the embodiment of the present application, the final target correction load can be calculated and applied to the non-jumping side wheel to simulate the actual stress condition of the non-jumping wheel.

[0136] See also Fig. 9 , Fig. 9 A schematic diagram of a load decomposition device provided in an embodiment of the present application. Fig. 9 As shown, the device comprises:

[0137] A model building unit 901 is used to build a multi-body model of a passenger car suspension;

[0138] An input vertical load applying unit 902 is used to select an upward jumping side wheel from the wheels in the passenger car suspension multi-body model, and apply an upward input vertical load to the ground contact point of the upward jumping side wheel;

[0139] The first acquisition unit 903 is used to select a non-jumping side wheel corresponding to the jumping side wheel, and acquire a target corrected load of the non-jumping side wheel according to a non-jumping side static condition; the value of the target corrected load is greater than the static load;

[0140] A target correction load applying unit 904 is used to apply the target correction load in an upward direction to the contact point of the non-jumping side wheel;

[0141] The second acquisition unit 905 is used to perform static load simulation based on the bus suspension multi-body model and using the applied input vertical load and the target correction load to obtain the six-axis force loads of the connection hard points between the bus suspension and the body.

[0142] Optionally, in some implementations of the embodiments of the present application, the first acquiring unit 903 includes:

[0143] A first acquisition subunit is used to acquire an initial value of the corrected load of the non-jumping side wheel;

[0144] The second acquisition subunit is used to perform iterative static load simulation based on the bus suspension multi-body model, using the input vertical load, the initial value of the correction load and the non-jumping side static condition to obtain the target correction load of the non-jumping side wheel.

[0145] Optionally, in some implementations of the embodiments of the present application, the first acquisition subunit includes:

[0146] A first calculation subunit is used to calculate the anti-roll force of the stabilizer bar bushing in the passenger car suspension;

[0147] The second calculation subunit is used to calculate the initial value of the corrected load based on the stabilizer bar bushing anti-roll force, the input vertical load, the axle load, the wheelbase, the distance from the stabilizer bar body end bushing to the body centerline, the distance from the body center of mass to the centerline and the stabilizer bar roll angle using the moment balance principle.

[0148] Optionally, in some implementations of the embodiments of the present application, the second acquisition subunit includes:

[0149] A correction load applying subunit is used to apply the correction load required for this iteration in an upward direction at the contact point of the non-jumping side wheel; when the correction load is applied for the first time, the value of the correction load is the initial value of the correction load;

[0150] A third acquisition subunit is used to perform static load simulation based on the bus suspension multi-body model, using the applied input vertical load and the correction load required for this iteration, to obtain the displacement information of the non-jumping side wheel;

[0151] A judging subunit, used to judge whether the displacement information is within a preset range;

[0152] A determination subunit, configured to determine the correction load required for this iteration as a target correction load when the judgment result of the judgment subunit is that the displacement information is within a preset range;

[0153] The correction load updating subunit is used to obtain an updated correction load using the correction load required for this iteration when the displacement information is not within the preset range, and use the updated correction load as the correction load required for the next iteration; repeatedly execute the correction load required for this iteration and subsequent steps of applying the correction load required for this iteration upward at the contact point of the non-jumping side wheel until the displacement information is within the preset range, and determine that the correction load required for this iteration is the target correction load.

[0154] Optionally, in some implementations of the embodiments of the present application, the model building unit 901 includes: an airbag spring model building subunit, used to build an airbag spring model;

[0155] The airbag spring model establishment subunit includes:

[0156] a fourth acquisition subunit, configured to acquire a multi-pressure stiffness curve of an airbag; the multi-pressure stiffness curve of the airbag is generated based on test data; the test data is acquired by setting a preset number of test pressure values ​​and performing a compression test on the airbag spring under the preset number of test pressure values; the test data includes a test applied force and a compression amount of the airbag spring;

[0157] a fifth acquisition subunit, configured to acquire an actual stiffness curve of the airbag spring by using a linear interpolation method based on the airbag multi-pressure stiffness curve and the actual air pressure of the environment where the airbag spring is located;

[0158] A subunit is established for establishing an airbag spring model based on an actual stiffness curve of the airbag spring.

[0159] The embodiment of the present application provides a load decomposition device, including: establishing a multi-body model of a bus suspension. Selecting a wheel on the jumping side from the wheels in the multi-body model of the bus suspension, and applying an input vertical load in an upward direction to the ground contact point of the wheel on the jumping side. Selecting a non-jumping side wheel corresponding to the wheel on the jumping side, and obtaining a target correction load for the wheel on the non-jumping side according to the static condition of the non-jumping side, wherein the value of the target correction load is greater than the static load. Applying an upward target correction load to the ground contact point of the wheel on the non-jumping side. Based on the multi-body model of the bus suspension, a static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-direction force loads of the hard points connecting the bus suspension and the body. In the embodiment of the present application, the actual wheel jumping condition of the vehicle is simulated, and an upward road load is applied to the ground contact point of the wheel on the jumping side of the multi-body model of the bus suspension, which essentially replaces the inertia load commonly used in the prior art with a road load. In addition, when applying road loads, considering that the bus suspension is a non-independent suspension, in order to make the force on the non-jumping side wheel in the bus suspension multi-body model consistent with the force on the non-jumping side wheel under the actual wheel jumping condition, and thus make the final extracted load at the hard point where the vehicle suspension and the body are connected more accurate, the target correction load in the upward direction is applied to the grounding point of the non-jumping side wheel to correct the force on the non-jumping side wheel. Finally, the load at the hard point where the vehicle suspension and the body are connected extracted by static load simulation based on the bus suspension multi-body model is more accurate and consistent with the actual driving condition of the bus.

[0160] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0161] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the method disclosed in the embodiment, since it corresponds to the system disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the system part description.

[0162] It should also be noted that, in this article, the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0163] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A load decomposition method, characterized in that: The method comprises: Establish a multi-body model of bus suspension; Selecting an upward-jumping-side wheel from the wheels in the passenger car suspension multi-body model, and applying an upward input vertical load to a ground contact point of the upward-jumping-side wheel; A non-jumping side wheel corresponding to the jumping side wheel is selected to obtain an initial value of a correction load of the non-jumping side wheel; based on the bus suspension multi-body model, an iterative static load simulation is performed using the input vertical load, the initial value of the correction load and the non-jumping side static condition to obtain a target correction load of the non-jumping side wheel; the value of the target correction load is greater than the static load; Applying the target correction load in an upward direction to the contact point of the non-jumping side wheel; Based on the bus suspension multi-body model, static load simulation is performed using the applied input vertical load and the target correction load to obtain the six-axis force loads of the connection hard points between the bus suspension and the body.

2. The method according to claim 1, characterized in that The obtaining of the initial value of the corrected load of the non-jumping side wheel comprises: Calculate the anti-roll force of stabilizer bar bushings in passenger car suspensions; The initial value of the corrected load is calculated based on the stabilizer bar bushing anti-roll force, the input vertical load, the axle load, the wheelbase, the distance from the stabilizer bar body end bushing to the body centerline, the distance from the body center of mass to the centerline and the stabilizer bar roll angle using the moment balance principle.

3. The method according to claim 1, characterized in that The method of performing iterative static load simulation based on the bus suspension multi-body model and using the input vertical load, the initial value of the modified load and the static condition of the non-jumping side to obtain the target modified load of the wheel on the non-jumping side includes: Applying the correction load required for this iteration in an upward direction at the contact point of the non-jumping side wheel; when the correction load is applied for the first time, the value of the correction load is the initial value of the correction load; Based on the bus suspension multi-body model, static load simulation is performed using the applied input vertical load and the correction load required for this iteration to obtain displacement information of the non-jumping side wheel; Determining whether the displacement information is within a preset range; If so, determine the correction load required for this iteration as the target correction load; If not, use the correction load required for this iteration to obtain an updated correction load, and use the updated correction load as the correction load required for the next iteration; repeat the steps of applying the correction load required for this iteration upward at the contact point of the non-jumping side wheel and subsequent steps until the displacement information is within the preset range, and determine that the correction load required for this iteration is the target correction load.

4. The method according to claim 1, characterized in that: The establishment of the bus suspension multi-body model comprises: establishing an airbag spring model; The airbag spring model is established, comprising: Acquire an airbag multi-pressure stiffness curve; the airbag multi-pressure stiffness curve is generated based on test data; the test data is obtained by setting a preset number of test pressure values ​​and performing a compression test on the airbag spring under the preset number of test pressure values; the test data includes a test applied force and a compression amount of the airbag spring; Based on the airbag multi-pressure stiffness curve and the actual air pressure of the environment where the airbag spring is located, using a linear interpolation method to obtain an actual stiffness curve of the airbag spring; An airbag spring model is established based on the actual stiffness curve of the airbag spring.

5. A load decomposition device, characterized in that: The device comprises: Model building unit, used to build a multi-body model of bus suspension; An input vertical load applying unit is used to select an upward jumping side wheel from the wheels in the passenger car suspension multi-body model, and apply an upward input vertical load to the ground contact point of the upward jumping side wheel; The first acquisition unit is used to select a non-jumping side wheel corresponding to the jumping side wheel, and acquire an initial value of a correction load of the non-jumping side wheel; based on the bus suspension multi-body model, using the input vertical load, the initial value of the correction load and the non-jumping side static condition, perform an iterative static load simulation to acquire a target correction load of the non-jumping side wheel; the value of the target correction load is greater than the static load; A target correction load applying unit, used for applying the target correction load in an upward direction to the contact point of the non-jumping side wheel; The second acquisition unit is used to perform static load simulation based on the bus suspension multi-body model and use the applied input vertical load and the target correction load to obtain the six-axis force load of the connection hard point between the bus suspension and the body.

6. The device according to claim 5, characterized in that The first acquisition unit includes: A first calculation subunit is used to calculate the anti-roll force of the stabilizer bar bushing in the passenger car suspension; The second calculation subunit is used to calculate the initial value of the corrected load based on the stabilizer bar bushing anti-roll force, the input vertical load, the axle load, the wheelbase, the distance from the stabilizer bar body end bushing to the body centerline, the distance from the body center of mass to the centerline and the stabilizer bar roll angle using the moment balance principle.

7. The device according to claim 5, characterized in that The second acquisition unit includes: A correction load applying subunit is used to apply the correction load required for this iteration in an upward direction at the contact point of the non-jumping side wheel; when the correction load is applied for the first time, the value of the correction load is the initial value of the correction load; A third acquisition subunit is used to perform static load simulation based on the bus suspension multi-body model, using the applied input vertical load and the correction load required for this iteration, to obtain the displacement information of the non-jumping side wheel; A judging subunit, used to judge whether the displacement information is within a preset range; A determination subunit, configured to determine the correction load required for this iteration as a target correction load when the judgment result of the judgment subunit is that the displacement information is within a preset range; The correction load updating subunit is used to obtain an updated correction load using the correction load required for this iteration when the displacement information is not within the preset range, and use the updated correction load as the correction load required for the next iteration; repeatedly execute the correction load required for this iteration and subsequent steps of applying the correction load required for this iteration upward at the contact point of the non-jumping side wheel until the displacement information is within the preset range, and determine that the correction load required for this iteration is the target correction load.

8. The device according to claim 5, characterized in that The model building unit includes: an airbag spring model building subunit, which is used to build an airbag spring model; The airbag spring model establishment subunit includes: a fourth acquisition subunit, configured to acquire a multi-pressure stiffness curve of an airbag; the multi-pressure stiffness curve of the airbag is generated based on test data; the test data is acquired by setting a preset number of test pressure values ​​and performing a compression test on the airbag spring under the preset number of test pressure values; the test data includes a test applied force and a compression amount of the airbag spring; a fifth acquisition subunit, configured to acquire an actual stiffness curve of the airbag spring by using a linear interpolation method based on the airbag multi-pressure stiffness curve and the actual air pressure of the environment where the airbag spring is located; A subunit is established for establishing an airbag spring model based on an actual stiffness curve of the airbag spring.

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