A modal parameter acquisition system and method suitable for rudder systems

Abstract

The application discloses a modal parameter acquisition system and method suitable for a rudder system, relates to the technical field of rudder system modal analysis, and comprises a load loading subsystem which is used for respectively processing corresponding aerodynamic force distributions according to preset aerodynamic parameters at multiple time points and respectively applying aerodynamic forces to rudder surfaces based on the multiple groups of aerodynamic force distributions. A modal test subsystem is used for performing modal tests on the rudder system when the aerodynamic forces are applied to the rudder surfaces, so as to acquire modal parameters of the rudder system under different aerodynamic forces. The application simulates the application of the aerodynamic forces to the rudder surfaces through the load loading system, acquires the modal parameters of the rudder system under the action of different aerodynamic forces, and improves the prediction accuracy of the modal parameters of the rudder system.

Description

Technical Field

[0001] This invention relates to the field of rudder system modal analysis technology, specifically to a system and method for obtaining modal parameters of rudder systems. Background Technology

[0002] The rudder system is a crucial actuator in an aircraft control system. Its modal parameters, including natural frequencies, mode shapes, and damping ratios, are essential parameters for flutter safety analysis and control system design. Obtaining these modal parameters is one of the design challenges for structures with nonlinear elements such as gaps.

[0003] Unlike conventional rudder systems, folding rudder systems have both a rudder drive mechanism and a rudder folding mechanism. There are gap nonlinearities in both the rudder surface rotation direction around the rudder axis and the rudder surface folding direction around the folding axis, making it difficult to accurately obtain the torsional and bending modal parameters of the folding rudder system.

[0004] During flight, the control surfaces of an aircraft are subjected to aerodynamic forces. Due to the nonlinearity of the clearance, the modal parameters of a folding control surface system are significantly affected by these aerodynamic forces. Conventional modal testing methods for control systems do not consider the impact of different aerodynamic forces on the control surfaces during flight on the nonlinearity of the clearance in the rotation and folding direction of the folding control surface system, leading to errors in the obtained modal parameters.

[0005] Therefore, it is urgent to design a method for accurately obtaining modal parameters to improve the prediction accuracy of modal parameters of the rudder system. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to propose a system and method for obtaining modal parameters of a rudder system. By applying aerodynamic forces to the rudder surface through a load loading subsystem, the modal parameters of the rudder system under different aerodynamic forces are obtained, thereby improving the prediction accuracy of the modal parameters of the rudder system.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A modal parameter acquisition system for a rudder system, comprising:

[0009] The load loading subsystem is used to process the aerodynamic parameters at multiple preset times to obtain the corresponding aerodynamic force distributions, and apply aerodynamic forces to the control surface based on the multiple sets of aerodynamic force distributions.

[0010] The modal testing subsystem is used to perform modal tests on the rudder system when the load loading subsystem applies simulated aerodynamic forces to the rudder surface, so as to obtain the modal parameters of the rudder system under different aerodynamic forces.

[0011] Preferably, the aerodynamic parameters include the aerodynamic shape of the control surfaces, flight speed, flight altitude, and control deflection angle.

[0012] Preferably, the load loading subsystem includes:

[0013] The aerodynamic selection module is used to calculate the aerodynamic force distribution and aerodynamic resultant force at each time based on the aerodynamic parameters at multiple preset times, and select the aerodynamic force distribution with the maximum aerodynamic resultant force, the aerodynamic force distribution with the minimum aerodynamic resultant force, and multiple aerodynamic force distributions between the maximum and minimum aerodynamic resultant forces from the aerodynamic force distributions at all times.

[0014] The load loading module is used to load different aerodynamic forces onto multiple aerodynamic zones of the control surface according to the selected multiple aerodynamic force distributions.

[0015] Preferably, the load loading module includes:

[0016] Multiple connecting surfaces are respectively attached to the multiple pneumatic zones;

[0017] A multi-stage force transmission assembly includes multiple layers of longitudinal connectors and multiple layers of transverse connectors. Adjacent longitudinal connectors in the same layer are connected by transverse connectors. Each transverse connector in each layer is connected to a longitudinal connector in the layer above. The connection points between the longitudinal connectors in the upper layer and the transverse connectors in the lower layer are set according to the aerodynamic force distribution. The number of longitudinal connectors in the lowest layer of the multi-stage force transmission assembly is the same as the number of aerodynamic zones, and each longitudinal connector in the lowest layer is connected to a corresponding aerodynamic zone. The number of longitudinal connectors in the highest layer of the multi-stage force transmission assembly is 1.

[0018] The load unit, which is connected to the uppermost longitudinal connector of the multi-stage force transmission assembly, is used to apply aerodynamic resultant force to the multi-stage force transmission assembly, so as to apply corresponding aerodynamic component force to each aerodynamic zone through the multi-stage force transmission assembly.

[0019] Preferably, the transverse connector is provided with a slide rail, and the top structure of the longitudinal connector connected to the transverse connector matches the slide rail.

[0020] Preferably, the load unit includes:

[0021] An elastic rope, one end of which is used to connect to the longitudinal connector of the uppermost layer of the multi-stage force transmission assembly, and the other end of which is used to connect to a weight;

[0022] A fixed pulley, the elastic rope passing around the fixed pulley and connecting to the weight;

[0023] The weight is related to the aerodynamic distribution.

[0024] Preferably, the modal parameters include natural frequency, mode shape, and damping ratio.

[0025] Preferably, the modal testing subsystem includes:

[0026] Multiple exciters are respectively set at multiple excitation points on the rudder surface to apply excitation force to the rudder surface;

[0027] Multiple acceleration sensors are respectively set at multiple acceleration acquisition points on the control surface to collect the acceleration of the control surface;

[0028] A modal testing device is connected to the plurality of exciters and the plurality of acceleration sensors to collect the excitation force and the acceleration, and to process the excitation force and the acceleration to obtain modal parameters.

[0029] A method for obtaining modal parameters of a rudder system, based on the aforementioned modal parameter acquisition system for a rudder system; the method includes:

[0030] The corresponding aerodynamic force distribution is obtained by processing the aerodynamic parameters at multiple preset times.

[0031] When the load loading subsystem applies aerodynamic forces to the rudder surface, the modal testing subsystem is used to conduct modal tests on the rudder system to obtain the modal parameters of the rudder system under different aerodynamic forces.

[0032] Preferably, when applying the aerodynamic force and conducting the modal test, the rudder system is installed on the rudder section after the section is fixedly installed on the ground.

[0033] Compared with the prior art, the advantages of the present invention are as follows:

[0034] Compared with existing technologies, this method considers the different aerodynamic forces experienced by the control surfaces during aircraft flight, especially the impact of different aerodynamic forces on the clearance nonlinearity of the control system. It obtains the modal parameters of the control system under different aerodynamic forces, reduces the error of modal test results caused by factors such as clearance nonlinearity, and provides more accurate parameters for structural dynamics model correction and attitude control system design. The accuracy of the identified modal frequencies, mode shapes, and damping ratios is high. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the functional modules of the modal parameter acquisition system applicable to the rudder system in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the aerodynamic simulation loading of the folding control surface in an embodiment of the present invention.

[0037] Figure 3This is a schematic diagram of the modal parameter acquisition system applicable to the rudder system in an embodiment of the present invention.

[0038] Figure 4 This is one of the schematic diagrams of the multi-stage force transmission component in the embodiments of the present invention.

[0039] Figure 5 This is one of the schematic diagrams of the multi-stage force transmission component in the embodiments of the present invention.

[0040] Figure label:

[0041] 1-Load loading subsystem; 2-Modal testing subsystem; 3-Lateral connector; 4-Pneumatic selection module; 5-Load loading module; 6-Vibrator; 7-Section; 8-Steering gear; 9-Control surface; 10-Acceleration sensor; 11-Connecting surface; 12-Multi-stage force transmission assembly; 13-Elastic rope; 14-Modal testing equipment; 15-Fixed pulley; 16-Weight; 17-Rudder shaft; 18-Folding shaft; 19-Longitudinal connector. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] like Figure 1 and Figure 3 As shown, this application provides a modal parameter acquisition system for a rudder system, comprising a load loading subsystem 1 and a modal testing subsystem 2. The load loading subsystem 1 is used to process aerodynamic parameters at multiple preset times to obtain corresponding aerodynamic force distributions, and apply aerodynamic forces to the rudder surface 9 based on the multiple sets of aerodynamic force distributions. The modal testing subsystem 2 is used to perform modal tests on the rudder system when the load loading subsystem applies aerodynamic forces to the rudder surface to obtain the modal parameters of the rudder system under different aerodynamic forces. The aforementioned aerodynamic force distributions include different aerodynamic forces experienced by multiple aerodynamic zones of the rudder surface 9.

[0044] In this embodiment, during flight, the control surface 9 is subjected to aerodynamic forces. Due to the nonlinearity of the gap, the modal parameters of the folded control surface 9 control system are significantly affected by aerodynamic forces. When the aerodynamic forces are small, the modal frequencies are very low and unstable; when the aerodynamic forces are large, the modal frequencies are high and tend to be stable.

[0045] Therefore, by collecting the aerodynamic parameters of the rudder system at multiple moments, processing the aerodynamic parameters at each moment to obtain the corresponding aerodynamic force distribution, and then applying aerodynamic forces to the rudder surface 9 at the aforementioned multiple moments using the load loading subsystem 1, and conducting modal tests on the rudder system at the aforementioned multiple moments using the aforementioned modal testing subsystem 2, the modal parameters of the rudder system under different aerodynamic forces can be obtained. This allows for a more accurate simulation of the rudder system's modal parameters during actual flight, i.e., under the influence of aerodynamic forces. The aerodynamic forces on the rudder surface include normal force and tangential force. The normal force has a greater impact on the modal parameters of the rudder system; therefore, this invention only considers the loading of the normal force.

[0046] In a preferred embodiment, the aforementioned aerodynamic parameters include the aerodynamic shape of the control surfaces, flight speed, flight altitude, and control deflection angle.

[0047] In a preferred embodiment, the load loading subsystem 1 includes a pneumatic selection module 4 and a load loading module 5.

[0048] The aerodynamic selection module 4 is used to calculate the aerodynamic force distribution and aerodynamic resultant force at each time according to the aerodynamic parameters at multiple preset times, and select the aerodynamic force distribution with the maximum aerodynamic resultant force, the aerodynamic force distribution with the minimum aerodynamic resultant force, and multiple aerodynamic force distributions between the maximum and minimum aerodynamic resultant forces from the aerodynamic force distributions at all times.

[0049] The load loading module 5 is used to load different aerodynamic forces on multiple aerodynamic zones of the control surface according to the selected multiple aerodynamic force distributions for modal testing.

[0050] In some other embodiments, the aerodynamic selection module 4 may also select aerodynamic distributions at multiple times from the aerodynamic distributions at all times according to a specified time interval.

[0051] In this embodiment, aerodynamic force distributions are obtained by processing aerodynamic parameters at multiple preset times, and aerodynamic forces are applied to the control surface 9 based on these multiple aerodynamic force distributions. For example, ... Figure 2 As shown, during modal testing of the folding control surface system, control surface 9 can rotate around control axis 17 and bend around folding axis 18. At a certain moment, the aerodynamic zones of control surface 9 are divided into sixteen zones, F01 to F16. The aerodynamic forces within each zone are the same, while the aerodynamic forces between different zones are different. Aerodynamic forces generally refer to the forces applied vertically to control surface 9. The circle in zone F02 is the installation point of the exciter in the bending direction, and the triangle in zone F16 is the installation point of the exciter in the torsional direction. By applying different aerodynamic forces to the multiple aerodynamic zones of control surface 9 according to the aerodynamic force distribution, the aerodynamic forces experienced by control surface 9 during aircraft flight can be accurately simulated.

[0052] In a preferred embodiment, such as Figure 3As described above, the load loading module 5 includes multiple connecting surfaces 11, a multi-stage force transmission assembly 12, and a load unit. The multiple connecting surfaces 11 are respectively attached to the multiple aerodynamic partitions, with each connecting surface 11 corresponding to one aerodynamic partition. The multi-stage force transmission assembly 12 receives the resultant force transmitted by the load unit, decomposes the resultant force into multiple different component forces, and then applies them to each aerodynamic partition of the control surface 9 through the connecting surfaces 11. The connecting surfaces 11 can be made of canvas.

[0053] Furthermore, the multi-stage force transmission assembly 12 includes multiple layers of longitudinal connectors 19 and multiple layers of transverse connectors 3. Two adjacent longitudinal connectors 19 in the same layer are connected by transverse connectors 3. Each transverse connector 3 in each layer is connected to a longitudinal connector 19 in the layer above. The connection points between the longitudinal connector 19 in the upper layer and the transverse connector 3 in the lower layer are set according to the above aerodynamic distribution.

[0054] The number of longitudinal connectors 19 in the lowest layer of the multi-stage force transmission assembly 12 is the same as the number of pneumatic partitions, and each longitudinal connector 19 in the lowest layer is connected to a corresponding pneumatic partition. The number of longitudinal connectors 19 in the highest layer of the multi-stage force transmission assembly 12 is 1.

[0055] The load unit is connected to the longitudinal connector 19 of the highest layer of the multi-stage force transmission assembly 12, and is used to apply aerodynamic resultant force to the multi-stage force transmission assembly 12, so as to apply corresponding aerodynamic component force to each aerodynamic zone through the multi-stage force transmission assembly 12.

[0056] In this embodiment, as Figure 4 As shown, when the calculated aerodynamic distribution indicates that the aerodynamic zones of the control surface 9 are sixteen zones from F01 to F16, five layers of longitudinal connectors 19 and four layers of transverse connectors 3 are set from the control surface 9 to the load unit. The bottom layer, i.e. the side connected to the control surface 9, includes 16 longitudinal connectors 19. Each pair of the 16 longitudinal connectors 19 is connected to eight transverse connectors 3. The eight transverse connectors 3 are connected to the longitudinal connectors 19 of the second layer. The second layer includes eight longitudinal connectors 19. Each pair of the eight longitudinal connectors 19 is connected to four transverse connectors 3. The four transverse connectors 3 are connected to the longitudinal connectors 19 of the third layer. The third layer includes four longitudinal connectors 19. Each pair of the four longitudinal connectors 19 is connected to two transverse connectors 3. The two transverse connectors 3 are connected to the longitudinal connectors 19 of the fourth layer. The fourth layer includes two longitudinal connectors 19. The two longitudinal connectors 19 are connected to each other by transverse connectors 3. The transverse connectors 3 are connected to one longitudinal connector 19 of the fifth layer. The longitudinal connector 19 can be made of wire rope or rigid bar, and the transverse connector 3 can be made of angle steel or connecting plate.

[0057] like Figure 5As shown, if the tension applied by the upper-level longitudinal connector 19 to the transverse connector 3 is f102, based on the length L of the transverse connector 3, the distance x1 from the connection point to one end of the transverse connector 3, and the distance x2 from the connection point to the other end of the transverse connector 3, according to the lever principle, the tensions on the two lower-level longitudinal connectors 19 are f01 and f02, respectively, where x1+x2=L, f01×x1=f02×x2.

[0058] In a preferred embodiment, the transverse connector 3 is provided with a slide rail, and the top structure of the longitudinal connector 19 connected to the transverse connector 3 matches the slide rail.

[0059] In this embodiment, by adjusting the connection point between the longitudinal connector 19 and the transverse connector 3, the force transmitted from the upper-level longitudinal connector 19 to the two lower-level longitudinal connectors 19 through the transverse connector 3 can be adjusted, and ultimately the aerodynamic resultant force applied by the load unit can be adjusted to the aerodynamic component force transmitted to each aerodynamic zone.

[0060] If the transverse connector 3 is not equipped with a slide rail, a collar that can be fitted onto the transverse connector 3 can be provided at the top of the longitudinal connector 19 to adjust the connection point position between the longitudinal connector 19 and the transverse connector 3.

[0061] In a preferred embodiment, such as Figure 3 The aforementioned load unit includes an elastic rope 13, a fixed pulley 15, and a weight 16. One end of the elastic rope 13 is used to connect to the longitudinal connector 19 of the highest layer in the multi-stage force transmission assembly 12, and the other end is used to connect to the weight 16. The elastic rope 13 passes around the fixed pulley 15 to connect to the weight 16. The weight of the weight 16 is related to the aforementioned aerodynamic force distribution.

[0062] In this embodiment, the multi-stage force transmission component 12 is installed on the side of the rudder surface 9 where the aerodynamic force is tension. The weight m of the weight 16 is determined according to the aerodynamic resultant force F, where m = F / g and g is the gravitational acceleration. The aerodynamic resultant force F can also be applied by replacing the weight 16 with a hydraulic cylinder.

[0063] In a preferred embodiment, the modal parameters include natural frequency, mode shape, and damping ratio.

[0064] The modal testing subsystem 2 includes multiple exciters 6, multiple acceleration sensors 10, and a modal testing device 14. The multiple exciters 6 are respectively disposed at multiple excitation points on the control surface 9 to apply excitation force to the control surface 9. The multiple acceleration sensors 10 are respectively disposed at multiple acceleration acquisition points on the control surface 9 to acquire the acceleration of the control surface 9. The modal testing device 14 is connected to the multiple exciters 6 and the multiple acceleration sensors 10 to acquire the excitation force and the acceleration, and to process the excitation force and the acceleration to obtain modal parameters.

[0065] This application also provides a method for obtaining modal parameters applicable to a rudder system, including...

[0066] The corresponding aerodynamic force distribution is obtained by processing the aerodynamic parameters at multiple preset times.

[0067] When the load loading subsystem 1 applies aerodynamic force to the rudder surface, the modal testing subsystem 2 described above is used to conduct modal tests on the rudder system to obtain the modal parameters of the rudder system under different aerodynamic forces.

[0068] Furthermore, when applying the aforementioned aerodynamic forces and conducting the aforementioned modal tests, after fixing section 7 to the ground, the rudder system is installed on section 7.

[0069] The control method of this embodiment is applicable to the above-mentioned control systems.

[0070] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A modal parameter acquisition system suitable for a rudder system, characterized in that, include: The load loading subsystem is used to process the aerodynamic parameters at multiple preset times to obtain the corresponding aerodynamic force distributions, and apply aerodynamic forces to the control surface based on the multiple sets of aerodynamic force distributions. The modal testing subsystem is used to perform modal tests on the rudder system when the load loading subsystem applies simulated aerodynamic forces to the rudder surface, so as to obtain the modal parameters of the rudder system under different aerodynamic forces. The load loading subsystem includes a load loading module, which includes multiple connection surfaces, a multi-stage force transmission component, and a load unit. The load unit is connected to the multi-stage force transmission component and is used to apply force to it. The load unit includes: an elastic rope, one end of which is used to connect to the multi-stage force transmission assembly, and the other end of which is used to connect to a weight; a fixed pulley, through which the elastic rope passes to connect the weight; and the weight, the weight of which is related to the aerodynamic force distribution. The modal testing subsystem includes: multiple exciters, each disposed at multiple excitation points on the control surface, for applying excitation force to the control surface; multiple acceleration sensors, each disposed at multiple acceleration acquisition points on the control surface, for acquiring the acceleration of the control surface; and a modal testing device, which connects the multiple exciters and the multiple acceleration sensors, for acquiring the excitation force and the acceleration, and processing the excitation force and the acceleration to obtain modal parameters.

2. The modal parameter acquisition system for a rudder system as described in claim 1, characterized in that, The aerodynamic parameters include the aerodynamic shape of the control surfaces, flight speed, flight altitude, and control deflection angle.

3. The modal parameter acquisition system for a rudder system as described in claim 1, characterized in that, The load loading subsystem includes: The aerodynamic selection module is used to calculate the aerodynamic force distribution and aerodynamic resultant force at each time based on the aerodynamic parameters at multiple preset times, and select the aerodynamic force distribution with the maximum aerodynamic resultant force, the aerodynamic force distribution with the minimum aerodynamic resultant force, and multiple aerodynamic force distributions between the maximum and minimum aerodynamic resultant forces from the aerodynamic force distributions at all times.

4. The modal parameter acquisition system for a rudder system as described in claim 3, characterized in that, The load loading module includes: Multiple connecting surfaces are respectively attached to the multiple pneumatic zones; A multi-stage force transmission assembly includes multiple layers of longitudinal connectors and multiple layers of transverse connectors. Adjacent longitudinal connectors in the same layer are connected by transverse connectors. Each transverse connector in each layer is connected to a longitudinal connector in the layer above. The connection points between the longitudinal connectors in the upper layer and the transverse connectors in the lower layer are set according to the aerodynamic force distribution. The number of longitudinal connectors in the lowest layer of the multi-stage force transmission assembly is the same as the number of aerodynamic zones, and each longitudinal connector in the lowest layer is connected to a corresponding aerodynamic zone. The number of longitudinal connectors in the highest layer of the multi-stage force transmission assembly is 1. The load unit, which is connected to the uppermost longitudinal connector of the multi-stage force transmission assembly, is used to apply aerodynamic resultant force to the multi-stage force transmission assembly, so as to apply corresponding aerodynamic component force to each aerodynamic zone through the multi-stage force transmission assembly.

5. The modal parameter acquisition system for a rudder system as described in claim 4, characterized in that, The transverse connector is provided with a slide rail, and the top structure of the longitudinal connector connected to the transverse connector matches the slide rail.

6. The modal parameter acquisition system for a rudder system as described in claim 1, characterized in that, The modal parameters include natural frequency, mode shape, and damping ratio.

7. A method for obtaining modal parameters of a rudder system, characterized in that, A modal parameter acquisition system for a rudder system based on any one of claims 1-6; the method includes: The corresponding aerodynamic force distribution is obtained by processing the aerodynamic parameters at multiple preset times. When the load loading subsystem applies aerodynamic forces to the rudder surface, the modal testing subsystem is used to conduct modal tests on the rudder system to obtain the modal parameters of the rudder system under different aerodynamic forces.

8. The method for obtaining modal parameters of a rudder system as described in claim 7, characterized in that, When applying the aerodynamic force and conducting the modal test, the cabin section is fixedly installed on the ground, and the rudder system is installed on the cabin section.

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