A multi-rotor dynamic test bench

Abstract

The application provides a multi-rotor dynamic test bed, comprising a center test bed, a fundamental frequency adjusting system, a center support hub, a motion support arm system, a dynamic hub system and an external system; the center test bed is connected with the fundamental frequency adjusting system through a diagonal bracing hinged mode, the top of the center test bed is connected with the center support hub, the center support hub is connected with the motion support arm system around, the motion support arm system is installed with the dynamic hub system, and the center test bed, the fundamental frequency adjusting system, the motion support arm system and the dynamic hub system are connected with the external system. Different rotor numbers, different rotor layouts, dynamic variable body and dynamic variable speed change test functions are realized.

Description

Technical Field

[0001] This invention belongs to the field of ground integrated testing technology for rotorcraft, and particularly relates to a multi-rotor dynamic test bench. Background Technology

[0002] Rotorcraft possess unique capabilities such as vertical takeoff and landing, hovering, ultra-low-altitude flight, and lateral movement. With advancements in battery technology, electric motors have become a viable power source for aircraft. Modern electric propulsion technology provides a solution for electrically driven vertical takeoff and landing aircraft, eliminating the need for engines and transmission systems. This "disassembles" the rotor into separate components, breaking the configuration limitations of traditional helicopters. Through configurational innovation, design goals such as high speed and high safety redundancy can be achieved. Furthermore, due to the characteristics of electric propulsion systems, the performance of the aircraft platform can remain largely consistent across plains and high-altitude environments.

[0003] Because electrically driven multirotor aircraft have multiple rotor systems with varying rotational speeds, the overall design phase is limited by existing test bench technology, making it impossible to use a universal test bench for multi-objective variations in the selection and design process. Existing multirotor aircraft test benches are mainly designed for single (four / six / eight) configurations and lack the ability to dynamically adjust the dynamic characteristics of the test bench itself. In other words, they cannot continuously conduct dynamic tests with a large range of rotational speed variations, and the test benches lack dynamic demonstration processes for variant multirotor aircraft. All of these problems limit the functionality of the test benches.

[0004] Therefore, there is an urgent need to develop a new type of variable fundamental frequency multi-functional multi-rotor dynamic test rig that combines the above features, so as to realize dynamic testing of different numbers of rotors and different test objectives. Summary of the Invention

[0005] To address the limitations of existing multirotor test benches, which primarily target single configurations and lack the ability to dynamically adjust the test bench's dynamic characteristics, as well as the absence of dynamic demonstration processes for variant multirotor aircraft, thus restricting the test bench's functionality, this invention provides a variable fundamental frequency multi-functional multirotor dynamic test bench for variable-speed helicopter rotor configurations, installation angles, and dynamic operation processes. It enables testing of different numbers of rotors, different rotor layouts, dynamic variants, and dynamic speed changes. Furthermore, it provides a variable fundamental frequency control scheme for the test bench during dynamic speed changes. This variable fundamental frequency dynamic test bench can be used for variable performance testing, dynamic testing, and flight mechanics testing of electrically driven variable-speed multirotor aircraft. The technical solution is as follows: In a first aspect, a multi-rotor dynamic test bench is provided, comprising: a central test bench frame 100, a base frequency adjustment system 200, a central support hub 300, a motion support arm system 400, a dynamic rotor hub system 500, and an external system 600. The central test bench 100 is connected to the base frequency adjustment system 200 by a diagonal brace hinge. The top of the central test bench 100 is connected to the central support hub 300. The central support hub 300 is connected to the motion support arm system 400 around its perimeter. The motion support arm system 400 is equipped with a dynamic propeller hub system 500. The central test bench 100, the base frequency adjustment system 200, the motion support arm system 400, and the dynamic propeller hub system 500 are all connected to the external system 600.

[0006] Optionally, the central test bench 100 includes: a vertical hydraulic actuator 101, a support bench 102, a bench height displacement sensor 103, a top flange 104, and a central support column 105; The support frame 102 is connected to the base frequency adjustment system 200, and the vertical hydraulic actuator 101 is connected to the servo controller of the external system 600. The servo controller applies commands to adjust the internal pressure of the vertical hydraulic actuator 101, thereby changing the height of the test platform and achieving the conversion between the rotor having ground effect and not having ground effect during the test. The platform height displacement sensor 103 is used to measure the ground height of the central support hub 300 at the upper end of the central test platform 100 and feeds the height back to the test equipment of the external system 600. The test equipment sends the height to the real-time loading management computer, which analyzes the rotor ground effect based on the height. The top flange 104 is located at the upper end of the central support column 105 and is used to connect the central support hub 300.

[0007] Optionally, the fundamental frequency regulation system 200 includes: a damping regulation cavity 201, damping particles 202, a liquid inlet 203, a liquid outlet 204, and a liquid level measurement sensor 205; The damping adjustment cavity 201 is connected to the support frame 102 of the central test rig 100. It is filled with damping particles 202, has an inlet 203 at the top and an outlet 204 at the bottom, and contains a liquid level sensor 205. The liquid level sensor 205 measures the liquid level height inside the damping adjustment cavity 201 and feeds the liquid level position information back to the test equipment of the external system 600. The test equipment sends the liquid level position information to the real-time loading management computer. Based on the liquid level position information, the real-time loading management computer analyzes the system's fundamental frequency and damping at that moment, and, combined with the rotor speed sent by the speed sensor 502, adjusts the fundamental frequency and damping. The inlet 203 and outlet 204, through the control system of the external system 600, adjust the inlet and outlet liquids to achieve the adjustment of the liquid level height, thereby realizing the adjustment of the fundamental frequency and damping of the multi-rotor dynamic test rig.

[0008] Optionally, the central support hub 300 includes: a U-shaped connecting device 301, a boom swing angle sensor 302, a central rotating shaft 303, and a connecting flange 304; The lower end of the central support hub 300 is connected to the top flange 104 of the central test bench 100 via a connecting flange 304, and the upper end of the central support hub 300 has at least two U-shaped connecting devices 301, which connect the motion arm system 400 to the central support hub 300 via a central rotating shaft 303. The outrigger swing angle sensor 302 is located on the outer edge of the central support hub 300. It is used to measure the swing angle of the outrigger system 400 and transmit the data to the test equipment of the external system 600 for positioning and controlling the angle of the outrigger system 400.

[0009] Optionally, the motion outrigger system 400 includes: an outrigger hydraulic actuator 401, an outrigger shaft 402, an outrigger shaft 403, a lead screw 404, a lead screw servo control motor 405, and a dynamic hub displacement sensor 406. The upper end of the hydraulic actuator cylinder 401 is connected to the support arm shaft 403 via the support arm shaft 402, and the lower end is connected to the lower end of the central support hub 300 via a hinge. The outrigger hydraulic actuator 401 is connected to a servo controller. By adjusting the internal hydraulic pressure, the outrigger swing angle can be adjusted in conjunction with the outrigger swing angle sensor 302. The lead screw 404 is installed next to the boom shaft 403. A dynamic propeller hub system 500 is mounted on the lead screw 404. The lead screw 404 is rotated by a lead screw servo control motor 405. At the same time, the dynamic propeller hub system 500 is positioned in conjunction with a dynamic propeller hub displacement sensor 406. The dynamic propeller hub displacement sensor 406 is connected to a testing device to locate the position of the dynamic propeller hub system 500. The lead screw servo control motor 405 is connected to a servo controller.

[0010] Optionally, the dynamic hub system 500 includes: hub adapter 501, speed sensor 502, tilt servo motor 505, dynamic hub angle sensor 506, tilt linkage mechanism 503, tilt slider 507, and brushless motor 504. The rotor hub adapter 501 is connected to the lead screw 404 of the motion support system 400. The rotor hub adapter 501 can move along the axial direction of the motion support system 400 under the movement of the lead screw 404. One end of the rotor hub adapter 501 is connected to the support shaft 403 through the tilting linkage mechanism 503. The rotor hub adapter 501 is connected to the rotor hub for rotor installation. The tilt servo motor 505 is mounted on the lower end of the propeller hub adapter 501. The motor actuator of the tilt servo motor 505 is connected to the tilt linkage mechanism 503 and the tilt slider 507. The forward tilt of the dynamic propeller hub system 500 is achieved by the operation of the tilt servo motor 505. The tilt servo motor 505 is also connected to the servo control system of the external system 600. The forward tilt of the dynamic hub system 500 is fed back to the test equipment through the dynamic hub angle sensor 506, which is used to load the management computer to obtain the tilt angle of the dynamic hub system 500 in real time. The brushless motor 504 is connected to the rotor hub adapter 501, and the upper end can be connected to the rotor system to perform the rotation function; the speed sensor 502 is installed on the rotor hub adapter 501 to measure the rotor system speed and feed it back to the test equipment.

[0011] Optionally, the external system 600 includes: a test load control center, a real-time load management computer, a modem, a power amplifier, a servo controller, a conditioning controller, and test equipment; The test loading control center connects to the real-time loading management computer and the test equipment; the loading management computer connects to the modem system, connects to the power amplifier through the servo controller and conditioning controller, and realizes various mechanical controls of the test bench through various actuators; the test equipment connects to various sensors through a modem and feeds back the processed signals to the test loading control center.

[0012] Optionally, when the fundamental frequency adjustment system 200 adjusts the fundamental frequency of the multi-rotor dynamic test bench, the fundamental frequency of the multi-rotor dynamic test bench falls within the range of... When within the specified range, the fundamental frequency adjustment system 200 adjusts the fundamental frequency of the multi-rotor dynamic test bench by opening the liquid outlet 204 and the liquid inlet 203; When h≥L / 2, and Then, open the liquid outlet 204 to release the liquid until the fundamental frequency of the multi-rotor dynamic test bench falls on the specified value. Within the range; When h < L / 2, and Then open the liquid inlet 203 to fill with liquid until the fundamental frequency of the multi-rotor dynamic test bench falls on Within the range, Where h is the liquid level height measured by the liquid level sensor 205, L is the maximum liquid level height of the damping adjustment cavity 201, and N is the number of blades in a single rotor blade. Ω represents the fundamental frequency of the multi-rotor dynamic test bench when the liquid level is h, and Ω represents the rotor speed, which is measured by the speed sensor 502.

[0013] The beneficial effects of this invention are at least as follows: A variable fundamental frequency multi-functional multirotor dynamic test bench addresses the requirements of different numbers of rotors, different rotor speeds, different flight states, different boom lengths, and rotor tilting during multirotor aircraft testing. First, a ground effect control system, composed of a vertical hydraulic actuator, a support frame, a frame height displacement sensor, and a test loading control center in the external system, enables adjustment of the rotor's ground clearance, thereby simulating rotor operation with and without ground effect. Second, the fundamental frequency adjustment system for the support frame consists of a damping adjustment cavity, damping particles, a liquid inlet, a liquid outlet, and a liquid level measurement sensor, coordinated and controlled by a speed sensor, a test loading control center, and a real-time loading management computer. The system can suppress vibration transmission from the rotor system to the test bench, and avoid resonance risks caused by rotor speed changes by adjusting its own natural frequency. Third, the motion outrigger system, composed of a hydraulic actuator cylinder, lead screw, and lead screw servo control motor, combined with the control function of the external system, can realize the position and tilt angle adjustment of the dynamic rotor hub system, thereby meeting the selection test requirements for dynamically adjusting the rotor outrigger angle and outrigger length. Fourth, the dynamic rotor hub system, composed of a rotor hub adapter, speed sensor, brushless motor, and tilt servo motor, combined with sensors and external systems, can complete the adjustment of rotor hub tilt and rotor speed changes, realizing dynamic tilt test of the rotor system and test at different speeds. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the control method of the present invention; Figure 2 This is a schematic diagram of a fundamental frequency multi-functional multi-rotor dynamic test system; Figure 3 Schematic diagram of the test bench at the center; Figure 4 This is a cross-sectional view of the baseband regulation system; Figure 5 Slanted view of the centrally supported hub; Figure 6 Front view of the central support hub; Figure 7 This is a schematic diagram of the motion boom system and the dynamic propeller hub system.

[0016] Among them, 100-Central test bench, 101-Vertical hydraulic actuator, 102-Support bench, 103-Bench height displacement sensor, 104-Top flange, 105-Central support column, 200-Fundamental frequency adjustment system, 201-Damping adjustment cavity, 202-Damping particles, 203-Liquid inlet, 204-Liquid outlet, 205-Liquid level measurement sensor, 300-Central support hub, 301-U-shaped connection, 302-Outrigger swing angle sensor, 303-Central rotating shaft, 304-Connection 400-Motion boom system, 401-Boom hydraulic actuator, 402-Boom shaft, 403-Boom main beam, 404-Lead screw, 405-Lead screw servo control motor, 406-Dynamic hub displacement sensor, 500-Dynamic hub system, 501-Hub adapter, 502-Speed ​​sensor, 503-Tilting linkage mechanism, 504-Brushless motor, 505-Tilting servo motor, 506-Dynamic hub angle sensor, 507-Tilting slider, 600-External system. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0019] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited from each other.

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] This invention provides a multi-rotor dynamic test bench, see [link to relevant documentation]. Figure 1 and Figure 2 It includes: a central test bench 100, a fundamental frequency adjustment system, a central support hub, a motion boom system, a dynamic propeller hub system, and an external system. The central test bench 100 is connected to the fundamental frequency adjustment system 200 via a diagonal brace hinge. A central support hub 300 is connected to the top of the central test bench 100. The central support hub 300 is connected to the motion support arm system 400 around its perimeter. A dynamic propeller hub system 500 is mounted on the motion support arm system 400. The central test bench 100, fundamental frequency adjustment system 200, motion support arm system 400, and dynamic propeller hub system 500 are all connected to external systems. See Figure 3 The central test bench includes: a vertical hydraulic actuator 101, a support frame 102, a top flange 104, a bench height displacement sensor 103, and a central support column 105. The support frame 102 is connected to a base frequency adjustment system. The vertical hydraulic actuator 101 is connected to a servo controller of an external system. The servo controller applies commands to adjust the internal pressure of the vertical hydraulic actuator 101, thereby changing the height of the test platform and achieving the conversion between the rotor having ground effect and not having ground effect during the test. The platform height displacement sensor 103 is used to measure the height of the central support hub at the upper end of the central test platform above the ground and feeds the height back to the test equipment of the external system. The test equipment sends the height to the real-time loading management computer, which analyzes the rotor ground effect based on the height. The top flange 104 is located at the upper end of the central support column 105 and is used to connect the central support hub.

[0022] See Figure 4 The fundamental frequency regulation system includes: a damping regulation cavity 201, damping particles 202, a liquid inlet 203, a liquid outlet 204, and a liquid level measurement sensor 205. The damping adjustment cavity 201 is connected to the support frame 102 of the central test rig. It is filled with damping particles 202, has a liquid inlet 203 at the upper end and a liquid outlet 204 at the lower end, and contains a liquid level measurement sensor 205. The liquid level measurement sensor 205 measures the liquid level height inside the damping adjustment cavity 201 and feeds the liquid level position information back to the external system's testing equipment. The testing equipment sends the liquid level position information to the real-time loading management computer. Based on the liquid level position information, the real-time loading management computer analyzes the system's fundamental frequency and damping at this time, and, combined with the rotor speed sent by the speed sensor 502, adjusts the fundamental frequency and damping. The liquid inlet 203 and liquid outlet 204, through the control system of the external system, adjust the inlet and outlet of the liquid to achieve the adjustment of the liquid level height, thereby realizing the adjustment of the fundamental frequency and damping of the multi-rotor dynamic test rig.

[0023] See Figure 5 and Figure 6 The central support hub includes: a boom swing angle sensor 302, a U-shaped connecting device 301, a central rotating shaft 303, and a connecting flange 304. The lower end of the central support hub is connected to the top flange 104 of the central test bench via a connecting flange 304, and the upper end of the central support hub has at least two U-shaped connecting devices 301. The motion support arm system is connected to the central support hub via a central rotating shaft 303. The outrigger swing angle sensor 302 is mounted on the outer edge of the central support hub to measure the swing angle of the outrigger system and transmit the data to the testing equipment of the external system for positioning and controlling the angle of the outrigger system.

[0024] See Figure 7 The outrigger system includes: outrigger hydraulic actuator 401, outrigger shaft 402, outrigger shaft 403, lead screw 404, lead screw servo control motor 405, and dynamic rotor hub displacement sensor 406. The upper end of the outrigger hydraulic actuator 401 is connected to the outrigger shaft 403 via the outrigger shaft 402, and the lower end is connected to the lower end of the central support hub via a hinge. The outrigger hydraulic actuator 401 is connected to a servo controller. By adjusting the internal hydraulic pressure, in conjunction with the aforementioned outrigger swing angle sensor 302, the outrigger swing angle can be adjusted. The lead screw 404 is installed next to the boom shaft 403. A dynamic propeller hub system is mounted on the lead screw 404. The rotation of the lead screw 404 is achieved by the lead screw servo control motor 405. At the same time, the dynamic propeller hub system is positioned in conjunction with the dynamic propeller hub displacement sensor 406. The dynamic rotor hub displacement sensor 406 is connected to the test equipment to locate the position of the dynamic rotor hub system. The lead screw servo control motor 405 is connected to the servo controller.

[0025] See Figure 7 The dynamic propeller hub system includes: a propeller hub adapter 501, a speed sensor 502, a tilt servo motor 505, a dynamic propeller hub angle sensor 506, a tilt linkage mechanism 503, a tilt slider 507, and a brushless motor 504. The hub adapter 501 is connected to the lead screw 404 of the motion outrigger system. The hub adapter 501 can move axially along the motion outrigger system under the movement of the lead screw 404. One end of the hub adapter 501 is connected to the outrigger shaft 403 through a tilting linkage mechanism 503. The rotor hub adapter 501 connects to the rotor hub for rotor installation. The tilt servo motor 505 is mounted on the lower end of the propeller hub adapter 501. The motor actuator of the tilt servo motor 505 is connected to the tilt linkage mechanism 503 and the tilt slider 507. The forward tilt of the dynamic propeller hub system is achieved by the operation of the tilt servo motor 505.

[0026] The tilt servo motor 505 is connected to the servo control system of an external system.

[0027] The forward tilt of the dynamic propeller hub system is fed back to the test equipment via the dynamic propeller hub angle sensor 506, which is used to load the management computer to obtain the tilt angle of the dynamic propeller hub system in real time.

[0028] The brushless motor 504 is connected to the rotor hub adapter 501, and the upper end can be connected to the rotor system to perform the rotation function.

[0029] The rotational speed sensor 502 is installed on the rotor hub adapter 501 and is used to measure the rotational speed of the rotor system and feed it back to the test equipment.

[0030] External systems include: test load control center, real-time load management computer, modem, power amplifier, servo controller, conditioning controller, and test equipment; The test loading control center is connected to the real-time loading management computer and the test equipment; the loading management computer is connected to the modem system, and is connected to the power amplifier through the servo controller and the conditioning controller, and realizes various mechanical controls of the test bench through the aforementioned actuators; The testing equipment connects to the aforementioned sensors via a modem and feeds back the processed signals to the test loading control center; When the fundamental frequency adjustment system 200 adjusts the fundamental frequency of the multi-rotor dynamic test bench, the fundamental frequency of the multi-rotor dynamic test bench falls within the range of... When within the specified range, the external system adjusts the fundamental frequency of the multi-rotor dynamic test bench by opening the liquid outlet 204 and the liquid inlet 203 of the fundamental frequency adjustment system 200. When h≥L / 2, and Then, open the liquid outlet 204 to release the liquid until the fundamental frequency of the multi-rotor dynamic test bench falls on the specified value. Within the range; When h < L / 2, and Then open the liquid inlet 203 to fill with liquid until the fundamental frequency of the multi-rotor dynamic test bench falls on Within the range; Where h is the liquid level height measured by the liquid level sensor 205, L is the maximum liquid level height of the damping adjustment cavity 201, and N is the number of blades in a single rotor blade. Ω represents the fundamental frequency of the multi-rotor dynamic test bench when the liquid level is h, and Ω represents the rotor speed (measured by speed sensor 502). Furthermore, the central support hub is replaceable, allowing for simulation of tests with different numbers of rotors; Furthermore, the connection between the lower flange 304 of the central support hub and the top flange 104 can be used to connect external equipment such as a balance and a torque testing device for testing the load of the rotor system, etc. Furthermore, the rotor system can be an N-bladed rotor; N is a natural number greater than or equal to 2; The external system achieves height adjustment through the movement of the vertical hydraulic actuator 101 of the central test bench 100. The height adjustment control method uses the following formula as the height determination value.

[0031] The height of the rotor hub above the ground; The height of the top flange 104 of the central test bench from the ground (measured by the bench height displacement sensor 103). The height from the central pivot 303 of the central support hub to the top flange 104; The angle of rotation of the outrigger pivot 403 around the central pivot 303 (upward is positive); The distance from the center shaft of the brushless motor 504 to the central rotating shaft 303 (measured by the dynamic hub displacement sensor 406). The empirical formula for determining the situation without ground effect is as follows:

[0032] The diameter is the rotor disk.

[0033] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A multi-rotor dynamic test bench, characterized in that, include: Central test bench (100), fundamental frequency adjustment system (200), central support hub (300), motion boom system (400), dynamic propeller hub system (500), external system (600). The central test bench (100) and the base frequency adjustment system (200) are connected by a diagonal brace hinge. The top of the central test bench (100) is connected to the central support hub (300). The central support hub (300) is connected to the motion support arm system (400) around its perimeter. The motion support arm system (400) is equipped with a dynamic propeller hub system (500). The central test bench (100), the base frequency adjustment system (200), the motion support arm system (400), and the dynamic propeller hub system (500) are all connected to the external system (600). The central test bench (100) includes: a vertical hydraulic actuator (101), a support bench (102), a bench height displacement sensor (103), a top flange (104), and a central support column (105). The support frame (102) is connected to the base frequency adjustment system (200), and the vertical hydraulic actuator (101) is connected to the servo controller of the external system (600). The servo controller applies commands to adjust the internal pressure of the vertical hydraulic actuator (101) to realize the change of the test platform height, thereby achieving the conversion between the rotor having ground effect and not having ground effect during the test. The frame height displacement sensor (103) is used to measure the ground height of the upper central support hub (300) of the central test frame (100) and feeds the height back to the test equipment of the external system (600). The test equipment sends the height to the real-time loading management computer, which analyzes the rotor ground effect based on the height. The top flange (104) is located at the upper end of the central support column (105) and is used to connect the central support hub (300). The fundamental frequency regulation system (200) includes: a damping regulation cavity (201), damping particles (202), a liquid inlet (203), a liquid outlet (204), and a liquid level measurement sensor (205); The damping adjustment cavity (201) is connected to the support frame (102) of the central test rig (100). It is filled with damping particles (202), has an inlet hole (203) at the top and an outlet hole (204) at the bottom, and contains a liquid level measurement sensor (205). The liquid level measurement sensor (205) is used to measure the liquid level height in the damping adjustment cavity (201) and feeds back the liquid level position information to the test equipment of the external system (600). The test equipment sends the liquid level position information to the real-time loading management computer. The real-time loading management computer analyzes the system fundamental frequency and damping at this time based on the liquid level position information, and adjusts the fundamental frequency and damping in conjunction with the rotor speed sent by the speed sensor (502). The inlet hole (203) and outlet hole (204) adjust the liquid inlet and outlet through the control system of the external system (600) to adjust the liquid level height, thereby realizing the adjustment of the fundamental frequency and damping of the multi-rotor dynamic test rig.

2. The multi-rotor dynamic test bench according to claim 1, characterized in that, The central support hub (300) includes: a U-shaped connecting device (301), a boom swing angle sensor (302), a central rotating shaft (303), and a connecting flange (304); The lower end of the central support hub (300) is connected to the top flange (104) of the central test bench (100) via a connecting flange (304), and the upper end of the central support hub (300) has at least two U-shaped connecting devices (301), and the motion arm system (400) is connected to the central support hub (300) via a central rotating shaft (303). The outrigger swing angle sensor (302) is located on the outer edge of the central support hub (300) and is used to measure the swing angle of the outrigger system (400). At the same time, it transmits the data to the test equipment of the external system (600) for positioning and controlling the angle of the outrigger system (400).

3. The multi-rotor dynamic test bench according to claim 2, characterized in that, The motion outrigger system (400) includes: outrigger hydraulic actuator (401), outrigger shaft (402), outrigger shaft (403), lead screw (404), lead screw servo control motor (405), and dynamic propeller hub displacement sensor (406). The upper end of the hydraulic actuator cylinder (401) is connected to the support arm shaft (403) via the support arm shaft (402), and the lower end is connected to the lower end of the central support hub (300) via a hinge. The outrigger hydraulic actuator (401) is connected to a servo controller. By adjusting the internal hydraulic pressure, the outrigger swing angle is adjusted in conjunction with the outrigger swing angle sensor (302). The lead screw (404) is installed next to the boom shaft (403). A dynamic propeller hub system (500) is mounted on the lead screw (404). The lead screw (404) is rotated by the lead screw servo control motor (405). At the same time, the dynamic propeller hub system (500) is positioned in conjunction with the dynamic propeller hub displacement sensor (406). The dynamic propeller hub displacement sensor (406) is connected to the test equipment to locate the position of the dynamic propeller hub system (500). The lead screw servo control motor (405) is connected to the servo controller.

4. The multi-rotor dynamic test bench according to claim 3, characterized in that, The dynamic hub system (500) includes: hub adapter (501), speed sensor (502), tilt servo motor (505), dynamic hub angle sensor (506), tilt linkage mechanism (503), tilt slider (507), and brushless motor (504). The hub adapter (501) is connected to the lead screw (404) of the motion support system (400). The hub adapter (501) can move axially along the motion support system (400) under the movement of the lead screw (404). One end of the hub adapter (501) is connected to the support shaft (403) through the tilting linkage mechanism (503). The hub adapter (501) is connected to the rotor hub for rotor installation. The tilt servo motor (505) is installed at the lower end of the propeller hub adapter (501). The motor actuator of the tilt servo motor (505) is connected to the tilt linkage mechanism (503) and the tilt slider (507). The forward tilt of the dynamic propeller hub system (500) is realized through the operation of the tilt servo motor (505). The tilt servo motor (505) is also connected to the servo control system of the external system (600). The forward tilt of the dynamic hub system (500) is fed back to the test equipment through the dynamic hub angle sensor (506) to load the management computer to obtain the tilt angle of the dynamic hub system (500) in real time; The brushless motor (504) is connected to the hub adapter (501), and the upper end can be connected to the rotor system and perform the rotation function; the speed sensor (502) is installed on the hub adapter (501) to measure the rotor system speed and feed it back to the test equipment.

5. The multi-rotor dynamic test bench according to claim 1, characterized in that, The external system (600) includes: a test load control center, a real-time load management computer, a modem, a power amplifier, a servo controller, a conditioning controller, and test equipment; The test loading control center connects to the real-time loading management computer and the test equipment; the loading management computer connects to the modem system, connects to the power amplifier through the servo controller and conditioning controller, and realizes various mechanical controls of the test bench through various actuators; the test equipment connects to various sensors through a modem and feeds back the processed signals to the test loading control center.

6. The multi-rotor dynamic test bench according to claim 1, characterized in that, When the fundamental frequency adjustment system (200) adjusts the fundamental frequency of the multi-rotor dynamic test bench, the fundamental frequency of the multi-rotor dynamic test bench falls within the range of 200. When within the range, the fundamental frequency adjustment system (200) adjusts the fundamental frequency of the multi-rotor dynamic test bench by opening the liquid outlet (204) and the liquid inlet (203); When h≥L / 2, and Then open the liquid outlet (204) to release the liquid until the fundamental frequency of the multi-rotor dynamic test bench falls on Within the range; When h < L / 2, and Then open the liquid inlet (203) to fill with liquid until the fundamental frequency of the multi-rotor dynamic test bench falls on Within the range, Where h is the liquid level height measured by the liquid level sensor (205), L is the maximum liquid level height of the damping adjustment cavity (201), and N is the number of blades in a single rotor blade. Ω is the fundamental frequency of the multi-rotor dynamic test bench when the liquid level is h, and Ω is the rotor speed, which is measured by the speed sensor (502).

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