CN117734960A - Fixed-wing aircraft flutter excitation test system and method - Google Patents

Abstract

The invention belongs to the field of flight test technology, and specifically relates to a fixed-wing aircraft flutter excitation test system and method. It includes an excitation device and a test system; the excitation device includes an excitation rocket arranged at an excitation point at the wingtip of an elastic structure on the aircraft, and an ignition control system electrically connected to the excitation rocket; the test system includes Airborne signal acquisition subsystem and vibration signal acquisition subsystem; the airborne signal acquisition subsystem includes a data acquisition recorder and a GPS antenna for recording the flight status parameters and GPS time of the aircraft; vibration signal acquisition subsystem It includes a low-frequency vibration acceleration sensor set at a test point on the rigid plane of the elastic structure on the aircraft, and a data acquisition recorder. The invention can accurately, conveniently and efficiently obtain various flutter modes through the excitation device, and obtain flight state parameters and vibration parameters required for flutter analysis through the test system.

Description

A fixed-wing aircraft flutter excitation test system and method

Technical field

The invention belongs to the field of flight test technology, and specifically relates to a fixed-wing aircraft flutter excitation test system and method.

Background technique

The Civil Aviation Administration of China's "Airworthiness Regulations for Normal Category Aircraft" (CCAR-23 Part R4 version) stipulates that normal category aircraft (herein generally refers to passenger seats with 19 or less seats and a maximum certified take-off weight of 8618 kg or The following aircraft) aeroelastic requirements, among which, Article 23.2245(a) (Article 23.629 in the R3 version of CCAR-23 Part 2) provides the relevant conditions for flutter test flight, but does not provide the excitation method during flutter test flight. The specific design method and the specific construction method of the measurement system.

Contents of the invention

The purpose of the invention is to propose a fixed-wing aircraft flutter excitation testing system and method, which can complete the generation of flutter excitation and the collection of test data.

Technical solution of the present invention: In order to achieve the above objects, according to the first aspect of the present invention, a fixed-wing aircraft flutter excitation test system is proposed, including an excitation device and a test system; the excitation device includes an elastic structure provided on the aircraft An excitation rocket at the excitation point at the wing tip, and an ignition control system electrically connected to the excitation rocket; the test system includes an airborne signal acquisition subsystem and a vibration signal acquisition subsystem; the airborne signal acquisition The subsystem includes a data acquisition recorder and a GPS antenna, which are used to record the flight status parameters and GPS time of the aircraft; the vibration signal acquisition subsystem includes the low-frequency vibration acceleration of the test point at the rigid plane of the elastic structure set on the aircraft. sensors, and a data acquisition recorder.

In a possible embodiment, the small excitation rocket is hard-connected to the wingtip of each elastic structure on the aircraft using bolts through an adapter structure.

In a possible embodiment, the elastic structure includes wings, horizontal stabilizers, and vertical stabilizers.

In a possible embodiment, one or more small excitation rockets are provided at each excitation point.

In a possible embodiment, the low-frequency vibration acceleration sensor is hard-connected to the rigid plane of each elastic structure on the aircraft through the adapter structure using bolts, and the installation location is selected at one point each at the front and rear of the fuselage; One point each at the front and rear.

In a possible embodiment, the ignition control system includes a mounting plate, a double-pole switch and a cable; through different combinations of the double-pole switch, only a single launch mode, only a simultaneous launch mode, and a single launch and dual launch coexistence mode are realized. ; It can improve the synchronization of the ignition action during the salvo of small rockets, and reduce or even eliminate the time difference between the ignition of two small rockets during the salvo. The double-pole switch is fixed on the mounting plate, and the mounting plate is installed together with the test system on a specially designed and installed fixed equipment rack in the cabin to achieve a high degree of integration of the control switches and secure installation of the test equipment, and at the same time facilitate the flight crew. Personnel operations.

In a possible embodiment, in the single launch mode only, the double-pole switch is connected to the double leads of each excitation small rocket; by directly operating and closing the double-pole switch of a single small rocket, the launch of the small rocket in the single-fire mode can be realized .

In a possible embodiment, in salvo-only mode, two small excitation rockets are first connected in series and then connected to the main double-pole switch; directly operating and closing the main double-pole switch of the two small excitation rockets can achieve small salvo-only mode. Rocket launch.

In a possible embodiment, in the coexistence mode of single launch and dual launch, separate double-pole switches are respectively set on the series circuits of the two small excitation rockets and then connected to the main double-pole switch; first, the main switch of the two small excitation rockets is closed. After the double-pole switch, then operate the separate double-pole switch to close the single excitation small rocket, so that the single launch of the excitation small rocket can be achieved; first operate the separate double-pole switch to close the single excitation small rocket, and then operate the combined switch to close the two excitation small rockets. The double-pole switch can realize the volley of small rockets.

According to the second aspect of the present invention, a fixed-wing aircraft flutter excitation testing method is proposed, which includes the following steps:

At the beginning of the test, after the aircraft starts the engine, turn on the power supply of the excitation device and the test system;

During the test, after the aircraft speed reaches the predetermined speed point, the ignition control system is operated to obtain the target flutter mode according to the predetermined small rocket ignition method;

After the experiment, the data from the data acquisition recorder is recovered, processed and analyzed.

Compared with the prior art, the beneficial effects of the present invention are:

The aircraft flight status parameters and vibration parameters obtained by the present invention can achieve GPS time synchronization, which facilitates determination of the start time and end time of the time period required for data analysis, and determination of the flight status parameters corresponding to the vibration parameters; the obtained flutter mode It can meet the modal requirements of theoretical analysis. The excitation device can realize various modes required for flutter analysis. The double-pole switch design controls the simultaneous disconnection and connection of the positive and negative stages, thus improving the reliability and safety of the system. . The invention can accurately, conveniently and efficiently obtain various flutter modes through the excitation device, and obtain flight state parameters and vibration parameters required for flutter analysis through the test system.

Description of drawings

Figure 1 is a schematic diagram of the architecture of a fixed-wing aircraft flutter excitation test system of the present invention;

Figure 2 is a schematic structural diagram of the ignition control system in a fixed-wing aircraft flutter excitation test system of the present invention;

Figure 3 is a schematic diagram of the actual installation of the small excitation rocket;

Figure 4 is a schematic diagram of the actual installation of the low-frequency acceleration sensor.

Detailed ways

In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only to further illustrate the features and advantages of the present invention and are not intended to limit the patent claims of the present invention.

1. Implementation method of excitation device:

Figure 1 illustrates the structure of the excitation device and the architecture of the test system.

Figure 2 illustrates the ignition control system structure.

The small excitation rocket in the excitation device is a shelf product. It is wrapped in a metal shell and filled with burning substances. Two ignition leads are reserved on the outside. When the two leads are connected, an electric spark is generated to ignite the small excitation rocket. The design thrust of the small rocket is 100 kilograms (converted to 0.98 kilonewtons after multiplying by the acceleration of gravity of 9.8 meters per square second), the design force duration is 20 milliseconds or 60 milliseconds, and the shape is cylindrical. Due to the use of explosions in the production process Therefore, it is necessary to entrust military industrial enterprises with certain qualifications to customize and produce such products.

The small excitation rocket uses bolts to be hard-connected to the wingtips of each elastic structure on the aircraft (wings, horizontal stabilizers, vertical stabilizers, etc.) through the adapter structure. According to the unilateral flutter mode and contralateral flutter mode Depending on the needs, one or more small excitation rockets can be installed at the wingtip of each elastic structure and ignited on demand to achieve the excitation of multiple flutter modes in the same sortie.

The ignition control system in the excitation device is a self-developed product, consisting of a mounting plate, several double-pole switches and cables. The excitation of the unilateral flutter mode is realized by the single shot of the small rocket, and the excitation of the symmetric flutter mode is realized by the salvo shot of the small rocket. Through different combinations of double-pole switches, the synchronization of the ignition action during the salvo of small rockets can be improved, and the time difference between the ignition of two small rockets during the salvo can be reduced or even eliminated. The double-pole switch is fixed on the mounting plate, and the mounting plate is installed together with the test system on a specially designed and installed fixed equipment rack in the cabin to achieve a high degree of integration of the control switches and secure installation of the test equipment, and at the same time facilitate the flight crew. Personnel operations.

The physical connection between the excitation rocket and the ignition control system is achieved through a shielded twisted pair cable. The internal wiring is preferred for the layout and fixation of the cable. If the internal wiring conditions cannot be met, additional cables must be added at certain distances on the external wiring path. Install a clamping block to fix the cable to prevent the cable from being too long and causing large swings during flight, which would affect the safety of the test flight.

The 28-volt power supply in the excitation device is drawn from the onboard power supply, and is connected in series with the ignition lead and double-pole switch of each small rocket to form a small rocket ignition control circuit. The ignition control circuits of each small rocket are connected in parallel with each other.

Taking the ignition control system structure in Figure 2 as an example, the operation method of the ignition control system will be explained in detail:

(1) Launch mode confirmation: the number of small rockets with only single-fire mode is 2 (XHJ1, XHJ2), the number of small rockets with only salvo-fire mode is 2 (XHJ3 and XHJ4, XHJ5 and The number of small rockets in coexistence mode is 4 (XHJ7, XHJ8, XHJ7 and XHJ8, XHJ9, XHJ10, XHJ9 and XHJ10).

(2) Operation method of single-shooting mode only: Directly operating the double-pole switch that closes a single small rocket can realize the launch of small rockets in single-shooting mode only. For example: operating the closed double-pole switch SD1 can achieve a single launch of the small rocket XHJ1; operating the closed double-pole switch SD2 can achieve a single launch of the small rocket XHJ2.

(3) Operation method of salvo-only mode: Directly operate the main double-pole switch that closes the two small rockets to realize the launch of small rockets in salvo-only mode. For example: operating the closed double-pole switch SD3 can realize the salvo of the small rockets XHJ3 and XHJ4; operating the closed double-pole switch SD4 can realize the salvo of the XHJ5 and XHJ6.

(4) How to operate the coexistence of single-shooting and double-shooting modes: first operate the main double-pole switch that closes the two small rockets, and then operate the separate double-pole switch that closes a single small rocket. Single shooting of the small rocket can be achieved; operate first Close the separate double-pole switch of a single small rocket, and then operate the main double-pole switch to close the two small rockets to achieve a salvo of small rockets. For example: first close the main double-pole switch SD5, and then close the branch double-pole switch SD6 (or SD7), you can achieve the single launch of the small rocket XHJ7 (or XHJ8); first close the main double-pole switch SD8, and then operate Close the separate double-pole switch SD9 (or SD10) to realize the single launch of the small rocket XHJ9 (or (or SD8), which can achieve salvo launch of small rockets XHJ7 and XHJ8 (or XHJ9 and XHJ10).

2. Implementation method of the airborne signal acquisition subsystem in the test system:

Figure 1 illustrates the structure of the excitation device and the architecture of the test system.

The airborne signal acquisition subsystem consists of an airborne signal data acquisition recorder and a GPS antenna, and is powered by an external on-board power supply (28 volts).

The airborne signal data acquisition and recorder is used to collect aircraft flight status parameters. The flight status parameters are collected and stored directly by the airborne signal data acquisition and recorder by extracting the bus signal on the aircraft. The data in the airborne signal data acquisition and recorder are The data is the same as the onboard signal and is installed on a specially designed and installed fixed equipment rack in the cabin. The airborne signal data acquisition recorder can use the KAM-500 data acquisition recorder produced by the Irish ACRA company.

The GPS antenna is used to provide GPS time to the test system. It can be divided into two operations through a power divider to convert one GPS input signal into two outputs, which are output to two data acquisition recorders (airborne signal data acquisition recorder). and airborne vibration data acquisition recorder). The GPS antenna is extended through an extension cable and installed on a specially designed and installed bracket in front of the aircraft cockpit windshield to enhance the GPS satellite signal search capability. The L1 antenna produced by Canadian NovAtel can be used.

3. Implementation method of vibration signal acquisition subsystem in test system:

Figure 1 illustrates the structure of the excitation device and the architecture of the test system.

The vibration measurement subsystem consists of a low-frequency vibration acceleration sensor and a data acquisition recorder, and is powered by an external on-machine power supply (28 volts).

The low-frequency vibration acceleration sensor uses bolts through the transfer structure to be hard-connected to each elastic structure (wing, horizontal stabilizer, vertical stabilizer, etc.) on the aircraft with good rigidity. The installation location selects the elastic structure (wing, horizontal stabilizer, etc.) , vertical stabilizer, etc.), and one point each at the front and rear of the fuselage. Modal supplementary selection related to the engine involves typical positions on the engine (reducer casing, etc.). The low-frequency acceleration sensor can use the 3741B1230G acceleration sensor produced by the American PCB Company.

The vibration signal data acquisition recorder is used to record and store the electrical signal converted from the vibration signal by each low-frequency vibration acceleration sensor (the GPS time is obtained by the GPS antenna in the airborne signal acquisition subsystem through a one-half method), and is installed in the cabin On the special fixed equipment rack designed and installed separately, the vibration signal data collector can use the SQLABⅡ data acquisition recorder produced by the German Acoustics Company.

The physical connection between the low-frequency acceleration sensor and the vibration signal data acquisition recorder is achieved through a dedicated cable. The internal wiring is preferred for the layout and fixation of the cable. If the internal wiring conditions cannot be met, additional cables must be added at certain distances on the external wiring path. Install a clamping block to fix the cable to prevent the cable from being too long and causing large swings during flight, which would affect the safety of the test flight.

Example 1

The Y-12F aircraft is a commuter, multi-purpose, all-metal, semi-monocoque small transport aircraft with a maximum take-off weight of 8,400 kg. This type of aircraft adopts twin engines, an upper monoplane, a single vertical tail, and retractable front three points. The overall layout of the landing gear. The left and right engine nacelles are respectively equipped with a PT6A-65B turboprop engine produced by Pratt & Whitney Canada (P&WC). Each engine is connected to an HC-C-B5MP-3D/ produced by the American Hartzell Company. M10876ANSK five-blade metal propeller with constant speed, feathering and reverse propeller functions.

(1) Installation location and method of small excitation rocket: During the flutter test flight of the Y-12F aircraft, elastic structures such as the left wing, right wing, left horizontal stabilizer, and right horizontal stabilizer were selected as the excitation locations. The small rocket was installed on the above structures. The position of the wingtip front beam (the direction of force is perpendicular to the ground direction). Each installation position is equipped with three small excitation rockets through the transfer structure, which are used to excite different modes and backup.

(2) Low-frequency acceleration sensor installation location and method: During the flutter test flight of the Y-12F aircraft, the left wing tip front beam, left wing tip rear beam, right wing tip front beam, right wing tip rear beam, and left horizontal stabilizer were selected Wingtip front beam, left horizontal stabilizer wingtip rear beam, right horizontal stabilizer wingtip front beam, right horizontal stabilizer wingtip rear beam, vertical stabilizer wingtip front beam, vertical stabilizer wingtip rear beam, left engine reducer box , right engine reducer box and other positions. An acceleration sensor is installed at each installation position through a transfer structure to collect and record acceleration signals.

(3) Chatter mode classification and excitation methods:

① Through the salvo of two small rockets from the left wing tip and the right wing tip, the "wing symmetrical 1 bend" mode is obtained.

② Through the salvo of two small rockets from the left horizontal stabilizer wingtip and the right horizontal stabilizer wingtip, the "horizontal stabilizer symmetrical 1 bend" and "engine symmetrical pitch" modes are obtained.

③ Through the single shot of a small rocket at the tip of the left wing, the modes of "wing anti-symmetrical 1 bend", "fuselage lateral 1 bend" and "engine room horizontal bend" are obtained.

④ Through the single shot of a small rocket on the left horizontal stabilizer wing tip, the modes of "vertical tail lateral 1 bend" and "flat tail anti-symmetrical 1 bend" are obtained.

Example 2

Specific operation methods of excitation device and test system:

Figure 3 illustrates the actual installation of the excitation rocket.

Figure 4 illustrates the actual installation of a low frequency acceleration sensor.

① Before the test starts, install the test equipment rack inside the cabin. The equipment rack has 3 layers in total. From top to bottom, they are: the first layer is the ignition control system, the second layer is the vibration signal data collector and the airborne signal data collector. , the third layer is the backup equipment layer; install the small excitation rocket and low-frequency acceleration sensor at the predetermined position, use cables to connect the small rocket to the ignition control system, and connect the acceleration sensor to the vibration signal data collector.

② At the beginning of the test, after the aircraft starts the engine, turn on the power supply of the excitation device and the test system.

③ During the test, after the aircraft speed reaches the predetermined speed point, the ignition control system is operated to obtain the target flutter mode according to the predetermined small rocket ignition method.

④After the test, recover, process and analyze the data from the data acquisition recorder.

⑤Determine whether to supplement the flight based on the test results.

test results:

Obtained 1 symmetric wing bend, 1 symmetric horizontal stabilizer bend, symmetric engine pitch, 1 anti-symmetric wing bend, 1 lateral bend of the fuselage, 1 horizontal engine bend, 1 lateral bend of the vertical tail, and anti-symmetric horizontal tail. 1 bend and other flutter modes, the test data under each mode are analyzed to obtain the amplitude-frequency curve, frequency-speed curve and damping ratio-speed curve. It can be seen from the test results that the Y-12F aircraft did not experience major vibration or buffeting at the dive speed V _D. Under the condition of small rocket excitation, the aircraft did not experience flutter, control adverse effects or divergence trends.

Claims (10)

1. A fixed-wing aircraft flutter excitation test system, characterized in that it includes an excitation device and a test system; the excitation device includes an excitation small rocket arranged at the excitation point at the wing tip of the elastic structure on the aircraft, and The ignition control system of the excitation rocket is electrically connected; the test system includes an airborne signal acquisition subsystem and a vibration signal acquisition subsystem; the airborne signal acquisition subsystem includes a data acquisition recorder and a GPS antenna, It is used to record the flight status parameters and GPS time of the aircraft; the vibration signal acquisition subsystem includes a low-frequency vibration acceleration sensor set at the test point on the rigid plane of the elastic structure on the aircraft, and a data acquisition recorder. 2. A fixed-wing aircraft flutter excitation test system according to claim 1, characterized in that the small excitation rocket is hard-connected to the wingtip of each elastic structure on the aircraft using bolts through an adapter structure. 3. A fixed-wing aircraft flutter excitation test system according to any one of claims 1 or 2, characterized in that the elastic structure includes a wing, a horizontal stabilizer, and a vertical stabilizer. 4. A fixed-wing aircraft flutter excitation test system according to claim 1, characterized in that one or more excitation small rockets are provided at each excitation point. 5. A fixed-wing aircraft flutter excitation test system according to claim 1, characterized in that the low-frequency vibration acceleration sensor is hard-connected to the rigid plane of each elastic structure on the aircraft using bolts through the adapter structure, and is installed. Select one point each at the front and rear of the fuselage; one point each at the front and rear of the elastic structure. 6. A fixed-wing aircraft flutter excitation test system according to claim 1, characterized in that the ignition control system includes a mounting plate, a double-pole switch and a cable; the double-pole switch is fixed on the mounting plate, and the The double-pole switch is connected to the small excitation rocket through a cable. Through different combinations of the double-pole switch, only a single launch mode, only a simultaneous launch mode, and a single launch and dual launch coexistence mode are realized. 7. A fixed-wing aircraft flutter excitation test system according to claim 6, characterized in that, in single launch mode only, the double-pole switch is connected to the double leads of each excitation small rocket; the single small rocket is directly operated to close The dual-pole switch can realize the launch of small rockets in single-shot mode only. 8. A fixed-wing aircraft flutter excitation test system according to claim 6, characterized in that, in the simultaneous launch mode only, two small excitation rockets are first connected in series and then connected to the main double-pole switch; the two small excitation rockets are directly operated to close Activate the main double-pole switch of the small rocket to realize the launch of the small rocket in salvo-only mode. 9. A fixed-wing aircraft flutter excitation test system according to claim 6, characterized in that, in single launch and dual launch coexistence modes, separate double-pole switches are respectively set on the two excitation small rockets in series circuits and then connected with each other. The main double-pole switch is connected; first operate and close the main double-pole switch of the two excitation small rockets, and then operate and close the separate double-pole switch of a single excitation small rocket to achieve a single shot of the excitation small rocket; first operate and close the single excitation small rocket. Separate double-pole switches, and then operate and close the two main double-pole switches that excite the small rockets to achieve a salvo of small rockets. 10. A fixed-wing aircraft flutter excitation test method, using a fixed-wing aircraft flutter excitation test system according to any one of claims 1 to 9, characterized in that it includes the following steps: At the beginning of the test, after the aircraft starts the engine, turn on the power supply of the excitation device and the test system; During the test, after the aircraft speed reaches the predetermined speed point, the ignition control system is operated to obtain the target flutter mode according to the predetermined small rocket ignition method; After the experiment, the data from the data acquisition recorder is recovered, processed and analyzed.