A simulation test device and method for the vibration reduction performance of a helicopter rotor pitch-change pull rod

Abstract

The present invention discloses a simulation test device and method for the vibration reduction performance of a helicopter rotor pitch rod, and relates to the field of testing mechanisms. The device can simulate blade vibration, test the vibration reduction performance of the pitch rod, and obtain the vibration reduction performance of the pitch rod under different working conditions. The simulation test device includes a load-bearing platform, a support seat, a mounting seat, a counterweight, a displacement sensor bracket, a displacement sensor, and a rotor simulation component. The top end of the pitch rod to be tested is mounted on the rotor simulation component, and the bottom end is mounted on the mounting seat. The rotor simulation component receives the vibration output by the fatigue testing machine, and after the vibration is transmitted through the pitch rod, the displacement of the mounting seat is obtained through the displacement sensor. The present invention has a simple structure, is easy to operate, and has clear and easy-to-understand results. It can measure the displacement data generated by the helicopter rotor pitch rod after receiving and transmitting the excitation, and then obtain its stiffness through calculation.

Description

Technical Field

[0001] The invention relates to the field of testing mechanisms, in particular to a testing device and method for testing the vibration reduction performance of a rotor pitch-changing pull rod by using a fatigue testing machine. Background Art

[0002] Current vibration reduction technologies for helicopters fall into two main categories: passive and active. Traditionally, passive vibration reduction technologies, such as stiffeners, dampers, or isolators, have been used to control helicopter vibration. The primary advantage of these devices is their simplicity. However, these passive technologies have limitations, such as their significant weight contribution to the aircraft. Furthermore, they operate only within a narrow frequency band and can only be tailored for specific flight regimes (i.e., forward flight at a specific speed). Due to these limitations, most current research in this field focuses on active vibration reduction. These systems are lighter than passive devices and can operate over a wider frequency band, enabling efficient flight under all flight conditions. Current active control vibration reduction technologies for helicopter rotors can be broadly categorized into three types: 1) active trailing edge flap control, 2) active rotor twist control, and 3) active pitch control. The first two technologies are based on helicopter blade systems and require modifications to the rotor blade geometry. Active pitch control technology, however, does not require modifications to the rotor blade shape; it only alters its stiffness. This is a significant difference from the first two approaches, and also offers the significant advantage of being retrofittable to any helicopter.

[0003] Common pitch rod vibration reduction technologies, such as those described in the Chinese invention patent application "A Helicopter Rotor Pitch Rod with Active Vibration Damping Mechanism" with application number "202310453068.4," require the pitch rod to be installed on the helicopter rotor in a fixed position near the rotor root. The design of this type of active pitch rod requires testing the vibration damping performance of a conventional pitch rod. Furthermore, the vibration damping performance of the designed pitch rod must be tested before formal application in a helicopter. However, the prior art does not disclose specific equipment or methods for conducting these tests.

[0004] In addition, considering that the axial dynamic load value of the pitch lever of the helicopter is different under different flight conditions, for example, the load analysis of the automatic tilter during helicopter maneuvering flight [J]. Science and Technology Innovation and Application, 2018, (01): 171-172+174, Wang Zefeng, Li Qinglong, etc.

[0005] Therefore, how to test the vibration reduction performance of the helicopter rotor pitch rod and obtain the vibration reduction performance of the pitch rod under different flight states, that is, under different working conditions, has become a technical problem that needs to be solved urgently by technical personnel in this field. Summary of the Invention

[0006] In response to the above problems, the present invention proposes a simulation test device and method for the vibration reduction performance of a helicopter rotor pitch rod, which can simulate blade vibration, test the vibration reduction performance of the pitch rod, and obtain the vibration reduction performance of the pitch rod under different working conditions.

[0007] The technical solution of the present invention is: the simulation test device is installed in a fatigue testing machine;

[0008] The fatigue testing machine includes a workbench 12, an actuator cylinder 1, a crossbeam 2, and a support frame 3. The crossbeam 2 is fixedly mounted above the workbench 12 via the support frame 3. The cylinder body of the actuator cylinder 1 is fixedly mounted on the crossbeam 2, and the cylinder rod of the actuator cylinder 1 extends downwardly below the crossbeam 2.

[0009] The simulation test device includes a carrying platform 10, a support base 7, a mounting base 11, a counterweight 13, a displacement sensor bracket 9, a displacement sensor, and a rotor simulation member 4. The carrying platform 10 is fixedly mounted on a workbench 12; the support base 7, the mounting base 11, and the counterweight 13 are all mounted on the carrying platform 10, and their positions in the length direction of the carrying platform 10 are adjustable; the displacement sensor is fixedly mounted on the mounting base 11 via the displacement sensor bracket 9, one end of the rotor simulation member 4 is fixedly mounted on the support base 7, and the other end of the rotor simulation member 4 is connected to the actuator 1 via a force transmission rod 15 and an upper clamp 17;

[0010] The top end of the pitch-changing rod 6 to be tested is mounted on the rotor simulation component 4, and the bottom end is mounted on the mounting seat 11. The vibration output by the fatigue testing machine is received through the rotor simulation component 4, and after being transmitted through the pitch-changing rod 6, the displacement of the mounting seat 11 is obtained through the displacement sensor.

[0011] Furthermore, a circular through hole 401 for connecting to the support seat 7 is formed at one end of the rotor simulation member 4, and a plurality of threaded holes 403 for connecting to the force transmission rod 15 are formed at the other end of the rotor simulation member 4. The plurality of threaded holes 403 are arranged in sequence along the length direction of the rotor simulation member 4.

[0012] The middle portion of the rotor simulation member 4 is provided with a square groove 402 and a through hole 404 for connecting the pitch-changing rod 6 , and the square groove 402 is arranged along the length direction of the rotor simulation member 4 ;

[0013] The rotor simulation component 4 is provided with three threaded holes 403 and two through holes 404. Starting from the connection point between the rotor simulation component 4 and the connecting support seat 7, the two through holes 404 and the three threaded holes 403 are arranged in sequence, and the ratio of the distance between the five to the connection point is 1:2.5:7.5:8.5:10.

[0014] Furthermore, a T-slot is provided on the bearing platform 10, and the bottom ends of the support seat 7, the mounting seat 11, and the counterweight block 13 are provided with sliders adapted to the T-slot. The support seat 7, the mounting seat 11, and the counterweight block 13 are detachably connected to the bearing platform 10 by bolts.

[0015] Furthermore, the support base 7 is installed on the carrying platform 10, and a simulation component mounting hole 701 for mounting the end of the rotor simulation component 4 is opened on the support base 7.

[0016] Furthermore, the bottom end of the variable pitch pull rod 6 to be tested is mounted on the mounting base 11 via the bracket 8;

[0017] One end of the bracket 8 is provided with an elliptical through hole 801 and is connected to the mounting base 11 by bolts. The other end of the bracket 8 is provided with a rectangular groove 803 for placing the bottom end of the variable pitch rod 6 and a circular hole 802 for connecting the bottom end of the variable pitch rod 6.

[0018] Furthermore, the positions of the support seat 7, the mounting seat 11, and the counterweight 13 in the longitudinal direction of the carrying platform 10 are adjusted according to the preset positions and fixed with bolts; then the rotor simulation part 4, the pitch rod 6, and the displacement sensor are installed;

[0019] Start the test, and apply a certain frequency and amplitude F to the rotor simulation part 4 through the actuator 1 of the fatigue testing machine. o The excitation force will also output the displacement x o The excitation will be applied to the helicopter rotor pitch rod 6 through the rotor simulation component 4 according to a certain ratio i, and the helicopter rotor pitch rod will be subjected to the excitation force (iF o ) generates vibration, and during the test, the fatigue testing machine collects the output excitation force F o and displacement x o The displacement sensor collects the bracket vibration data x i ; Then collect vibration data x through the displacement sensor i , and the displacement x output by the fatigue testing machine o The calculation of the helicopter rotor pitch rod vibration reduction performance is: k = (ix o -x i ) / (ix o ).

[0020] The vibration reduction performance test of the helicopter rotor pitch rod under different working conditions is achieved by adjusting the connection position of the actuator 1, the pitch rod 6 and the rotor simulation part 4;

[0021] In the dive pull-up condition, the axial force on the pitch-changing rod 6 reaches more than 10,000 N. At this time, the connection ratio between the actuator 1, the pitch-changing rod 6 and the rotor simulation component 4 is adjusted to 10:1. At this time, i=10, and the output of the fatigue testing machine is only 2,000 N.

[0022] Under the conditions of sharp turns and autorotation, the axial force on the pitch-changing rod 6 is about 3000N. At this time, the connection ratio between the actuator 1, the pitch-changing rod 6 and the rotor simulation component 4 is adjusted to 3:1; at this time, i=3, and the output of the fatigue testing machine is 1000N.

[0023] The beneficial effects of the present invention are:

[0024] 1) This device simulates the actual working conditions of the helicopter rotor pitch rod, solving the problem that the pitch rod vibration reduction performance test cannot be carried out on the real device due to the large size of the helicopter rotor structure and the high processing difficulty.

[0025] 2) This device uses a fatigue testing machine to output an excitation signal of a certain amplitude and frequency to obtain the displacement and excitation force transmitted by the variable pitch rod to the bracket. The vibration reduction performance of the variable pitch rod can be obtained by calculating the ratio of the displacement transmitted by the variable pitch rod to the bracket and the displacement output by the fatigue testing machine, and the stiffness of the variable pitch rod can be obtained by the excitation force and the displacement of the variable pitch rod.

[0026] 3) This device can realize the vibration reduction performance test of the rotor pitch rod under different working conditions of the helicopter by changing the relative positions of the force transmission rod and the pitch rod.

[0027] In summary, the present invention has a simple structure, is easy to operate, and produces clear and understandable results. It can measure the displacement data of a helicopter rotor pitch rod after receiving and transmitting excitation, and then calculate its stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the structural diagram of this case.

[0029] Figure 2 This is a schematic diagram of the helicopter rotor pitch rod vibration reduction performance test structure under different working conditions.

[0030] Figure 3 This is a top view of the rotor simulation

[0031] Figure 4 This is the front view of the rotor simulation

[0032] Figure 5 This is a structural diagram of the support seat

[0033] Figure 6 Yes, schematic diagram of the bracket structure

[0034] Figure 7 This is a schematic diagram of the mounting structure

[0035] Figure 8 This is a cross-sectional view of the mounting base.

[0036] Figure 9 is the axial force dynamic load value of the pitch rod under different flight conditions

[0037] Explanation of the accompanying numbers: 1. Actuating cylinder; 2. Crossbeam; 3. Support frame; 4. Rotor simulation component; 5. Pitch rod connecting bolt; 6. Pitch rod; 7. Support seat; 8. Bracket; 9. Displacement sensor bracket; 10. Load-bearing platform; 11. Mounting seat; 12. Workbench; 13. Counterweight; 14. Load-bearing platform fixing bolt; 15. Force transmission rod; 16. Nut; 17. Upper clamp. DETAILED DESCRIPTION

[0038] In order to clearly illustrate the technical features of this patent, this patent is described in detail below through specific implementation methods and in combination with its accompanying drawings.

[0039] The working principle of this device is that the fatigue testing machine applies a certain compression amount and frequency excitation to the rotor simulation part through the force transmission rod. The excitation received by the rotor simulation part will be transmitted to the pitch rod, and the pitch rod will then transmit the received excitation to the bracket. The bracket is designed to simulate the connection method between the pitch rod and the rotating swash plate, which is used to ensure that the pitch rod can produce corresponding displacement when receiving the excitation. Since the pitch rod has a certain vibration reduction performance, the excitation amplitude transmitted to the bracket is smaller than the excitation amplitude output by the fatigue testing machine. By calculating the ratio of the two, the vibration reduction performance of the pitch rod can be obtained.

[0040] This device can simulate the actual operating conditions of a helicopter rotor pitch lever, resolving the problem of inability to test the pitch lever's vibration damping performance on a real device due to factors such as excessive structural size and manufacturing difficulty. With its simple structure, easy operation, and clear, easily interpretable results, it can measure the force and displacement of the helicopter rotor pitch lever, as well as calculate its stiffness. The device can determine the displacement and excitation force transmitted to the bracket by the pitch lever. The pitch lever's vibration damping performance is calculated by calculating the ratio of the displacement transmitted by the pitch lever to the fatigue testing machine's output displacement, while the pitch lever's stiffness is determined by the ratio of the excitation force to the pitch lever's displacement. The device can also test the rotor pitch lever's vibration damping performance under different helicopter operating conditions by varying the relative positions of the force transmission rod and the pitch lever.

[0041] Specific implementation method Figure 1-2 As shown by Figure 9It can be seen that under different working conditions of the helicopter, the axial force on the pitch rod is different, and the maximum value is close to 12000N. Considering the output excitation range and accuracy of the hydraulic press, the required excitation can be output by changing the relative position of the pitch rod and the dowel rod. Figure 1 The excitation of the variable pitch rod in the installation method shown is 6 times the output excitation of the fatigue testing machine, which can be applied to the working condition where the axial force of the variable pitch rod is large. Figure 2 In the installation method shown, the excitation received by the variable pitch tie rod is 2.5 times the output excitation of the fatigue testing machine, which can be applied to working conditions where the axial force on the variable pitch tie rod is small.

[0042] Structurally, if Figure 1 As shown, the simulation test device in the present invention is installed in a fatigue testing machine;

[0043] The fatigue testing machine includes a workbench 12, an actuator cylinder 1, a crossbeam 2, and a support frame 3. The crossbeam 2 is fixedly mounted above the workbench 12 via the support frame 3. The cylinder body of the actuator cylinder 1 is fixedly mounted on the crossbeam 2, and the cylinder rod of the actuator cylinder 1 extends downwardly below the crossbeam 2.

[0044] The simulation test device includes a carrying platform 10, a support seat 7, a mounting seat 11, a counterweight 13, a displacement sensor bracket 9, a displacement sensor and a rotor simulation member 4. The carrying platform 10 is fixedly mounted on a workbench 12. The support seat 7, the mounting seat 11 and the counterweight 13 are all mounted on the carrying platform 10, and their positions in the length direction of the carrying platform 10 are adjustable; the displacement sensor is fixedly mounted on the mounting seat 11 via the displacement sensor bracket 9, one end of the rotor simulation member 4 is fixedly mounted on the support seat 7, and the other end of the rotor simulation member 4 is connected to the actuator cylinder 1 via a force transmission rod 15 and an upper clamp 17;

[0045] The top end of the pitch-changing rod 6 to be tested is mounted on the rotor simulation component 4, and the bottom end is mounted on the mounting seat 11. The vibration output by the fatigue testing machine is received through the rotor simulation component 4, and after being transmitted through the pitch-changing rod 6, the displacement of the mounting seat 11 is obtained through the displacement sensor.

[0046] like Figure 3 、 4 As shown, one end of the rotor simulation member 4 is provided with a circular through hole 401 for connecting to the support seat 7, and the other end of the rotor simulation member 4 is provided with a plurality of threaded holes 403 for connecting to the force transmission rod 15. The plurality of threaded holes 403 are arranged in sequence along the length direction of the rotor simulation member 4;

[0047] A square groove 402 and a through hole 404 for connecting the pitch-changing rod 6 are provided in the middle of the rotor simulation part 4 , and the square groove 402 is arranged along the length direction of the rotor simulation part 4 .

[0048] The rotor simulation component 4 is provided with three threaded holes 403 and two through holes 404. Starting from the connection point between the rotor simulation component 4 and the connecting support seat 7, the two through holes 404 and the three threaded holes 403 are arranged in sequence, and the ratio of the distance between the five to the connection point is 1:2.5:7.5:8.5:10.

[0049] In this way, the distance between the threaded hole 403, the through hole 404 and the connection portion between the rotor simulation member 4 and the connection support seat 7 can form 6 ratio results, namely 3:1, 3.4:1, 4:1, 7.5:1, 8.5:1, and 10:1, so as to facilitate the simulation. Figure 9 The loads generated under different helicopter operating conditions are shown in the figure. When the axial force is large (for example, the force exceeds 10,000N during a dive pull-up condition), the two positions can be connected at a ratio of 10:1. When the axial force is small (for example, the force is close to 3,000N during a sharp turn descent condition), the two positions can be connected at a ratio of 3:1.

[0050] The carrying platform 10 is provided with a T-slot, and the bottom ends of the support seat 7, the mounting seat 11, and the counterweight block 13 are provided with sliders adapted to the T-slot. The support seat 7, the mounting seat 11, and the counterweight block 13 are detachably connected to the carrying platform 10 by bolts.

[0051] like Figure 5 As shown, the support base 7 is installed on the carrying platform 10, and a simulation component mounting hole 701 for mounting the end of the rotor simulation component 4 is opened on the support base 7.

[0052] like Figure 6 As shown, the bracket 8 is designed to simulate the connection method between the pitch rod and the rotating swash plate, which is used to ensure that the rotor pitch rod can produce corresponding displacement when stimulated. An elliptical through hole 801 is opened at one end of the bracket 8 and is connected to the mounting seat 11 by bolts. The other end of the bracket 8 is provided with a rectangular groove 803 for placing the bottom end of the pitch rod 6 and a circular hole 802 for connecting the bottom end of the pitch rod 6.

[0053] like Figure 7 、 8 As shown, the mounting seat 11 is arranged on the bearing platform, and a plurality of threaded holes are opened on the mounting seat 11 for mounting the bracket and the displacement sensor bracket.

[0054] When conducting a helicopter rotor pitch change pull rod vibration reduction performance test, the specific test steps of the present invention are as follows:

[0055] Step 1: Install the load-bearing platform 10 onto the workbench 12 of the testing machine, fix it in place with bolts and nuts, and then install the upper fixture 17 of the testing machine onto the actuating rod 1 of the testing machine;

[0056] Step 2: Install the support base 7 to one side of the carrying platform 10 and connect it to the carrying platform 10 through bolts, and install the mounting base 11 near the support base 7 and also connect it to the carrying platform through bolts;

[0057] Step 3: Install a counterweight 13 of a certain weight on the other side. In subsequent installations, the weight of the counterweight 13 should be appropriately increased to ensure that the forces on both sides of the workbench 12 are balanced.

[0058] Step 4: Install the rotor simulation 4 on the support base 7. The end of the rotor simulation 4 is connected to the top of the support base 7 by bolts, with the other side facing the side where the counterweight 13 is located;

[0059] Step 5: Adjust the position of the support base 7 so that the threaded hole on the rotor simulator 4 is aligned with the through hole of the upper fixture 17. After the position adjustment is completed, tighten the nut to fix the position of the support base. Then install the force transmission rod 15. The force transmission rod passes through the through hole of the upper fixture 17 and is connected to the rotor simulator 4 by threading. Then, tighten a nut 16 on the upper and lower surfaces of the upper fixture 17 to fix the position of the force transmission rod 15 relative to the upper fixture 16.

[0060] Step 6: Install the bracket 8 on the mounting seat 11 with bolts, adjust the position of the mounting seat 11, align the through hole of the bracket 8 connected to the helicopter rotor pitch rod 6 with the circular through hole of the rotor simulation component 4 connected to the helicopter rotor pitch rod 6, and then tighten the nut to fix the position of the mounting seat 11.

[0061] Step 7: Install the helicopter rotor pitch rod 6 and adjust the bracket position so that one end of the helicopter rotor pitch rod 6 is connected to the rotor simulation component 4 and the other end is connected to the bracket 8.

[0062] Step 8: The mounting base 11 is provided with threaded holes for mounting the displacement sensor bracket, and the displacement sensor is mounted according to the test conditions.

[0063] Step 9: Start the test and apply a certain frequency and amplitude F to the rotor simulation part 4 o The excitation force will also output the displacement x o The excitation will be applied to the helicopter rotor pitch rod 6 through the rotor simulation component 4 according to a certain ratio i, and the helicopter rotor pitch rod will be subjected to the excitation force (iF o ) generates vibration, and during the test, the fatigue testing machine collects the output excitation force F o and displacement x o The displacement sensor collects the bracket vibration data x i .

[0064] Step 10: Collect vibration data x through displacement sensor i , and the displacement x output by the fatigue testing machine o The vibration reduction performance of the helicopter rotor pitch rod is calculated as follows:

[0065] k=(ix o -x i ) / (ix o ).

[0066] The vibration reduction performance test of the helicopter rotor pitch rod under different working conditions can be achieved by adjusting the connection position of the actuator cylinder 1 and the pitch rod 6 with the rotor simulation component 4. For example, under the diving and pulling-up working condition, the axial force value of the pitch rod 6 can reach more than 10,000 N. At this time, the connection ratio of the actuator cylinder 1, the pitch rod 6 and the rotor simulation component 4 is adjusted to 10:1. At this time, i=10, and the fatigue testing machine only needs to output 1 / 10 of the axial force value under the diving and pulling-up working condition, that is, about 2,000 N, to ensure the precision and accuracy of the excitation applied by the fatigue testing machine. Under the conditions of sharp turns and autorotation, the axial force on the pitch-changing rod 6 is about 3000N, which is smaller than that under other conditions. At this time, the connection ratio between the actuator 1, the pitch-changing rod 6 and the rotor simulation component 4 can be adjusted to 3:1; at this time, i=3, and the fatigue testing machine only needs to output 1 / 3 of the axial force value under the dive pull-up condition, that is, about 1000N, to ensure the precision and accuracy of the excitation applied by the fatigue testing machine.

[0067] It should be noted that in this case, threaded holes were opened at a certain ratio on the rotor simulator to facilitate testing the vibration reduction performance of the pitch lever under different operating conditions. The design of this test device is based on the structure of traditional helicopter pitch levers and variable stiffness pitch levers, and can also be applied to the vibration reduction performance testing of levers of similar structures.

[0068] There are many specific implementation ways of the present invention. The above is only the preferred implementation method of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be considered as the scope of protection of the present invention.

Claims

1. A simulation test device for the vibration reduction performance of a helicopter rotor pitch rod, characterized in that: The simulation test device is installed in a fatigue testing machine; The fatigue testing machine comprises a workbench (12), an actuating cylinder (1), a crossbeam (2) and a support frame (3); the crossbeam (2) is fixedly mounted above the workbench (12) via the support frame (3); the cylinder body of the actuating cylinder (1) is fixedly mounted on the crossbeam (2), and the cylinder rod of the actuating cylinder (1) extends downward to below the crossbeam (2); The simulation test device comprises a bearing platform (10), a support seat (7), a mounting seat (11), a counterweight (13), a displacement sensor bracket (9), a displacement sensor and a rotor simulation member (4); the bearing platform (10) is fixedly mounted on a workbench (12); the support seat (7), the mounting seat (11) and the counterweight (13) are all mounted on the bearing platform (10), and the positions of the three in the length direction of the bearing platform (10) are adjustable; the displacement sensor is fixedly mounted on the mounting seat (11) via the displacement sensor bracket (9); one end of the rotor simulation member (4) is fixedly mounted on the support seat (7), and the other end of the rotor simulation member (4) is connected to the actuator cylinder (1) via a force transmission rod (15) and an upper clamp (17); The top end of the variable pitch pull rod (6) to be tested is mounted on the rotor simulation component (4), and the bottom end is mounted on the mounting seat (11). The vibration output by the fatigue testing machine is received through the rotor simulation component (4), and after being transmitted through the variable pitch pull rod (6), the displacement of the mounting seat (11) is obtained through the displacement sensor.

2. The device for simulating and testing the vibration reduction performance of a helicopter rotor pitch rod according to claim 1, characterized in that: One end of the rotor simulation member (4) is provided with a circular through hole (401) for connecting to the support seat (7), and the other end of the rotor simulation member (4) is provided with a plurality of threaded holes (403) for connecting to the force transmission rod (15), and the plurality of threaded holes (403) are arranged in sequence along the length direction of the rotor simulation member (4); A square groove (402) and a through hole (404) for connecting a pitch-changing pull rod (6) are provided in the middle of the rotor simulation part (4), and the square groove (402) is arranged along the length direction of the rotor simulation part (4); The rotor simulation component (4) is provided with three threaded holes (403) and two through holes (404). Starting from the connection point between the rotor simulation component (4) and the connection support seat (7), the two through holes (404) and the three threaded holes (403) are arranged in sequence, and the ratio of the distances between the five through holes (404) and the connection point is 1:2.5:7.5:8.5:

10.

3. The device for simulating and testing the vibration reduction performance of a helicopter rotor pitch rod according to claim 1, characterized in that: The bearing platform (10) is provided with a T-shaped slot, and the bottom ends of the support seat (7), the mounting seat (11), and the counterweight (13) are provided with a sliding block adapted to the T-shaped slot, and the support seat (7), the mounting seat (11), and the counterweight (13) are detachably connected to the bearing platform (10) by bolts.

4. The device for simulating and testing the vibration reduction performance of a helicopter rotor pitch rod according to claim 1, characterized in that: The support seat (7) is mounted on the bearing platform (10), and a simulation component mounting hole (701) for mounting the end of the rotor simulation component (4) is provided on the support seat (7).

5. The device for simulating and testing the vibration reduction performance of a helicopter rotor pitch rod according to claim 1, characterized in that: The bottom end of the variable pitch pull rod (6) to be tested is mounted on the mounting seat (11) via a bracket (8); One end of the bracket (8) is provided with an elliptical through hole (801) and is connected to the mounting seat (11) by bolts. The other end of the bracket (8) is provided with a rectangular groove (803) for placing the bottom end of the variable pitch pull rod (6) and a circular hole (802) for connecting the bottom end of the variable pitch pull rod (6).

6. A method for testing the vibration reduction performance of a helicopter rotor pitch rod based on the simulation test device of claim 1, characterized in that: Adjust the positions of the support seat (7), the mounting seat (11), and the counterweight (13) in the length direction of the carrying platform (10) according to the preset positions and fix them with bolts; then install the rotor simulation component (4), the pitch rod (6), and the displacement sensor; Start the test, apply a certain frequency and amplitude F to the rotor simulation part (4) through the actuator (1) of the fatigue testing machine. o The excitation force will also output the displacement x o The excitation will be applied to the helicopter rotor pitch rod (6) through the rotor simulation component (4) according to a certain ratio i, and the helicopter rotor pitch rod is subjected to the excitation force (iF o ) generates vibration, and during the test, the fatigue testing machine collects the output excitation force F o and displacement x o The displacement sensor collects the bracket vibration data x i ; Then collect vibration data x through the displacement sensor i , and the displacement x output by the fatigue testing machine o The calculation of the helicopter rotor pitch rod vibration reduction performance is: k = (ix o -x i ) / (ix o ); The vibration reduction performance test of the helicopter rotor pitch change lever under different working conditions is achieved by adjusting the connection position of the actuator (1), the pitch change lever (6) and the rotor simulation component (4); Under the diving pull-up condition, the axial force on the pitch-changing rod (6) reaches more than 10,000 N. At this time, the connection ratio of the actuator (1), the pitch-changing rod (6) and the rotor simulation component (4) is adjusted to 10:

1. At this time, i=10, and the output of the fatigue testing machine is only 2,000 N. Under the conditions of sharp turns and autorotation glides, the axial force on the pitch-changing rod (6) is about 3000N. At this time, the connection ratio between the actuator (1), the pitch-changing rod (6) and the rotor simulation component (4) is adjusted to 3:1; at this time, i=3, and the output of the fatigue testing machine is 1000N.

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