A runway test device and method for measuring aerodynamic performance of unmanned tiltrotor aircraft

Abstract

The application discloses a kind of measurement unmanned tiltrotor aircraft aerodynamic performance's running car test device in the technical field of rotorcraft testing, comprising: carrying platform, for carrying unmanned tiltrotor aircraft to be measured, and can complete in closed road back and forth to carry out constant-speed straight line motion, carrying platform is installed with shock-absorbing platform to isolate car body vibration, shock-absorbing platform is installed with test rack;Test rack, including support rack, the lower end of support rack is installed on shock-absorbing platform by four three-component force sensor components, the upper end of support rack is provided with support frame, support frame is connected with the landing gear of unmanned tiltrotor aircraft to be measured, the rear part of landing gear is hinged on support frame, the front part of landing gear is connected with support frame through actuator, actuator is used to change the pitch direction attitude of unmanned tiltrotor aircraft to be measured;Unmanned tiltrotor aircraft, pull sensor is installed on its rotor system, the present application enables test personnel to test unmanned tiltrotor aircraft in wind tunnel.

Description

Technical Field

[0001] This invention relates to the field of rotorcraft testing technology, and in particular to a rotorcraft aerodynamic testing device. Background Technology

[0002] Existing unmanned tiltrotor aircraft combine the low-speed hovering performance of helicopters with the high-speed cruise performance of fixed-wing aircraft. Compared to the latter two, they have a wider flight envelope and advantages such as low operating costs, high transport capacity, and low noise and vibration. Testing the interference effects between the rotor and wing is one of the important basic researches for the development of unmanned tiltrotor aircraft. The rotor-wing interference effect test includes tests on lift, drag, pitch moment, and rudder effectiveness. Conventional aerodynamic tests are mainly conducted in conjunction with wind tunnel units. However, due to the short research history of unmanned tiltrotor aircraft in China, major domestic wind tunnel units do not yet have the conditions to conduct wind tunnel tests for unmanned tiltrotor aircraft. Furthermore, the accuracy of unmanned tiltrotor aircraft test results is greatly affected by the size of the test model. If the test model is scaled down too small, the test results will be distorted and deviate significantly from the actual flight results, making it difficult to have a positive impact on subsequent research. Because the transmission and power systems of unmanned tiltrotor aircraft are large, and the testing process involves rotor rotation and rotor system tilting, traditional wind tunnels have no relevant testing experience, and the safety of testing in wind tunnels has not been fully demonstrated.

[0003] The following problems exist in the testing of this field in the existing technology:

[0004] 1) In traditional wind tunnel testing, due to the size limitations of the wind tunnel test section, it is necessary to scale down the test object on a large scale. The test results of the interference between the rotor and wing of the unmanned tiltrotor aircraft are greatly affected by the size of the scaled-down model. If the scale is too small, the test results will be unusable due to distortion.

[0005] 2) Due to limitations in the transmission system (including rotor rotation and nacelle tilting) and power system (high-power motors and power supply) of unmanned tiltrotor aircraft, the test model cannot be scaled down too small;

[0006] 3) Conducting unmanned tiltrotor aircraft testing in traditional wind tunnels requires suspending other wind tunnel tests for modification and installing test benches, resulting in long testing cycles and high testing costs;

[0007] 4) The test is a dynamic test, involving the rotation of the rotor and the tilting of the rotor system of the unmanned tiltrotor aircraft. Due to the lack of relevant experience, there is a risk that the rotating parts of the test may be thrown out and damage the wind tunnel wall.

[0008] 5) Simply waiting for the wind tunnel unit to have the testing conditions before carrying out wind tunnel tests seriously restricts the project progress. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a test apparatus and method for measuring the aerodynamic performance of unmanned tiltrotor aircraft, thus solving the aforementioned technical problems.

[0010] The objective of this invention is achieved as follows: a test apparatus for measuring the aerodynamic performance of an unmanned tiltrotor aircraft, comprising:

[0011] The transport platform is used to transport the unmanned tiltrotor aircraft to be tested and is capable of performing constant-speed linear motion back and forth within a closed road. The transport platform is equipped with a shock-absorbing platform to isolate the vehicle body vibration, and a test rig is installed on the shock-absorbing platform.

[0012] The test bench includes a support frame. The lower end of the support frame is mounted on a vibration damping platform via four three-component force sensor assemblies. The upper end of the support frame is provided with a support frame, which is connected to the landing gear of the unmanned tiltrotor aircraft under test. The rear part of the landing gear is hinged to the support frame, and the front part of the landing gear is connected to the support frame via an actuator. The actuator is used to change the pitch attitude of the unmanned tiltrotor aircraft under test.

[0013] Unmanned tiltrotor aircraft have tension sensors installed on their rotor systems.

[0014] As a preferred technical solution of the sports car test device for measuring the aerodynamic performance of an unmanned tiltrotor aircraft according to the present invention, the support frame includes a hydraulic cylinder installed on a high platform. The piston rod of the hydraulic cylinder is fixedly connected to the bottom of the support frame through a connecting flange. The four three-component force sensor assemblies are installed on the four corners of the bottom surface of the high platform.

[0015] As a preferred technical solution of the sports car test device for measuring the aerodynamic performance of an unmanned tiltrotor aircraft according to the present invention, a pair of hinge seats are provided at the rear position of the top of the support frame, a pair of actuators are hinged at the front position of the top of the support frame, the landing gear is mounted on the connecting frame, the rear part of the connecting frame is hinged in the hinge seats, and the front part of the connecting frame is hinged to the actuators.

[0016] As a preferred technical solution of the test device for measuring the aerodynamic performance of an unmanned tiltrotor aircraft according to the present invention, the connecting frame includes a truss, a clamp, and a lug. The truss includes a pair of connecting rods for connecting the landing gear. The connecting rods have arc-shaped grooves that mate with the landing gear. The landing gear is fixedly connected to the connecting rods by the clamp. The two connecting rods are connected by a support rod and a support tube. The lug is installed at the bottom of the support rod, and the support tube is hinged in the hinge seat.

[0017] As a preferred technical solution of the test device for measuring the aerodynamic performance of an unmanned tiltrotor aircraft according to the present invention, the support frame includes a flange disposed at the bottom of the support frame, the four corners of the support frame are connected to the flange by connecting rods, the flange is connected to the connecting flange by bolts, and the support frame is arranged at an angle with its front end lower than its rear end.

[0018] As a preferred technical solution of the sports car test device for measuring the aerodynamic performance of an unmanned tiltrotor aircraft according to the present invention, the three-component force sensor assembly includes a signal acquisition unit disposed between the upper wall plate and the lower wall plate. The signal acquisition unit is used to transmit the detected pressure. The upper wall plate is fixed to the bottom of the support frame, and the lower wall plate is fixed to the transport platform.

[0019] A test method for measuring the aerodynamic performance of an unmanned tiltrotor aircraft includes the following steps:

[0020] Step 1) Install the test bench onto the transport platform;

[0021] Step 2) The unloaded transport platform moves forward at a speed V to conduct the test and obtains the pressure information detected by the three-component force sensors, which is recorded as the first state point data;

[0022] Step 3) Install the unmanned tiltrotor aircraft onto the test bench and adjust the angle of attack. α The carrier platform advances again at a speed of V to conduct the test, and obtains the pressure information detected by the three-component force sensor, which is recorded as the second state point data.

[0023] Step 4) Subtract the first state point data from the second state point data to obtain the net force data X. 4A X 4B X 4C X 4D、 Y 4A Y 4B Y 4C Y 4D ;

[0024] Step 5) Calculate the axial force F A Normal force F N And pitching moment M Z :

[0025]

[0026] In this diagram, 4A, 4B, 4C, and 4D represent four three-component force sensors, X, Y, and Z represent the force components detected by the three-component force sensors in three directions, T represents the thrust of the two rotors of the unmanned tiltrotor aircraft, L1 represents the distance between the center of mass of the unmanned tiltrotor aircraft and 4A along the length of the three-component force sensors 4A and 4C, L2 represents the distance between the center of mass of the unmanned tiltrotor aircraft and 4C along the length of the three-component force sensors 4A and 4C, and L4 represents the distance between the center of mass of the unmanned tiltrotor aircraft and the sensor plane.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention enables testers to conveniently install, debug, and test unmanned tiltrotor aircraft in the workshop. After confirming that the test conditions are met, the aircraft under test can be directly transported to the test site. Once the aircraft arrives at the test site, the test can begin immediately, which can effectively ensure the test progress.

[0029] In the test site, such as a closed road, the driver starts the transport vehicle and maintains a set speed for uniform linear motion. The test personnel can conveniently adjust the angle of attack, rotor speed and collective pitch angle of the tiltrotor aircraft under test, as well as the angles of the aircraft's various control surfaces (such as ailerons, rudder and elevator) from the cockpit, which has very high test efficiency.

[0030] The test system is easy to move and has great flexibility, enabling it to be quickly transferred between different test sites, thus reducing test costs.

[0031] The test does not require additional fabrication of a wind tunnel test model; the aircraft prototype can be directly installed on the test rig to carry out the test, saving project funds. Attached Figure Description

[0032] 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. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0034] Figure 2 This is a schematic diagram of the components of the transport vehicle in this invention.

[0035] Figure 3 This is a schematic diagram of the test bench components in this invention.

[0036] Figure 4 This is a schematic diagram of the components of the unmanned tiltrotor aircraft in this invention.

[0037] Figure 5 This is a top-view schematic diagram of the unmanned tiltrotor aircraft of this invention.

[0038] Figure 6 This is a schematic diagram showing the arrangement of the three-component force sensor assembly in this invention.

[0039] Figure 7 This is a side view of the system in the 0 angle of attack state in this invention.

[0040] Figure 8 This is a side view of the non-zero angle of attack state in this invention.

[0041] Figure 9 This is a schematic diagram illustrating the coordinate system definition in this invention.

[0042] Figure 10 The principle of force application in the system of this invention Figure 1 .

[0043] Figure 11 The principle of force application in the system of this invention Figure 2 .

[0044] Figure 12 This is a schematic diagram of different experimental states in this invention.

[0045] Among them, 1 is the transport platform, 101 is the flatbed truck, 102 is the shock absorber, 2 is the test bench, 201 is the high platform, 202 is the hydraulic cylinder, 203 is the connecting flange, 204 is the actuator, 205 is the hinge, 206 is the support frame, 3 is the unmanned tiltrotor aircraft, 301 is the fuselage, 302 is the wing, 303 is the rotor system, 304 is the tail, 305 is the nacelle, 307 is the landing gear, 308 is the connecting frame, 308a is the truss, 308b is the clamp, 308c is the lug, 309 is the power system, 309a is the tension sensor, 4 is the three-component force sensor assembly, 401 is the upper wall panel, 402 is the lower wall panel, and 403 is the signal acquisition unit. Detailed Implementation

[0046] 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, and 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. Example

[0047] like Figure 1-8 The test apparatus shown is a sports car test device for measuring the aerodynamic performance of an unmanned tiltrotor aircraft, comprising:

[0048] The transport platform 1 is used to transport the unmanned tiltrotor aircraft 3 to be tested and can complete the constant speed linear motion back and forth in a closed road. The transport platform 1 is equipped with a shock absorber 102 to isolate the vehicle body vibration, and the shock absorber 102 is equipped with a test stand 2.

[0049] Test bench 2 includes a support bench. The lower end of the support bench is mounted on a shock absorber 102 via four three-component force sensor assemblies 4. The upper end of the support bench is provided with a support frame 206. The support frame 206 is connected to the landing gear 307 of the unmanned tiltrotor aircraft 3 under test. The rear part of the landing gear 307 is hinged to the support frame 206. The front part of the landing gear 307 is connected to the support frame 206 via an actuator 204. The actuator 204 is used to change the pitch attitude of the unmanned tiltrotor aircraft 3 under test.

[0050] The unmanned tiltrotor aircraft 3 has a fuselage 301, wings 302, rotor system 303, tail 304, nacelle 305, landing gear 307, connecting frame 308, and power system 309. The rotor system 303 is equipped with a tension sensor 309a.

[0051] Specifically, in this embodiment, the test process is carried out in a wind tunnel. The transport platform 1 is a flatbed truck 101, and the shock absorber 102 is installed on the flatbed of the flatbed truck 101. First, four three-component force sensor assemblies 4 are installed on the shock absorber 102, and then the test rig 2 is installed on the four three-component force sensor assemblies 4. Before that, the support frame 206 can be installed on the support rig. After the test rig 2 is installed, the landing gear 307 of the unmanned tiltrotor aircraft 3 to be tested is installed on the support frame 206. Force data is detected by the tension sensor 309a and the four three-component force sensors. Then, the angle of attack data is preset and adjusted by the actuator 204. The angle of attack is the included angle on both sides of the hinge point. Finally, the force data and angle of attack data are used to calculate and obtain various test data.

[0052] Furthermore, the support frame includes a hydraulic cylinder 202 mounted on the high platform 201. The piston rod of the hydraulic cylinder 202 is fixedly connected to the bottom of the support frame 206 via a connecting flange 203. Four three-component force sensor assemblies 4 are mounted on the four corners of the bottom surface of the high platform 201.

[0053] Specifically, the elevated platform 201 adopts a frame structure, and the hydraulic cylinder 202 is installed on the top of the elevated platform 201. The piston rod lifts and lowers to drive the unmanned tiltrotor aircraft 3 under test, thereby simulating the corresponding scenario.

[0054] Furthermore, a pair of hinge seats 205 are provided at the rear of the top of the support frame 206, and a pair of actuators 204 are hinged at the front of the top of the support frame 206. The landing gear 307 is mounted on the connecting frame 308, the rear of the connecting frame 308 is hinged in the hinge seats 205, and the front of the connecting frame 308 is hinged to the actuators 204.

[0055] Specifically, the hinge 205 has a built-in bearing, the landing gear 307 is hinged in the hinge 205, and the actuator 204 includes an actuating cylinder in the middle and telescopic rods at both ends, with the telescopic rods at both ends respectively hinged to the connecting frame 308 and the support frame 206.

[0056] It should be noted that when adjusting the angle of attack, the angle of attack can be adjusted by controlling the actuator 204. In addition, the design of the connecting frame 308 facilitates the installation of the landing gear 307. The landing gear 307 can be installed on the connecting frame 308, thus adapting to different models of rotorcraft tests. Only the corresponding connecting frame 308 needs to be replaced.

[0057] Furthermore, the connecting frame 308 comprises a truss 308a, a clamp 308b, and a lug 308c. The truss 308a includes a pair of connecting rods for connecting the landing gear 307. The connecting rods have arc-shaped grooves that mate with the landing gear 307. The landing gear 307 is fixedly connected to the connecting rods via the clamp 308b. The two connecting rods are connected via a support rod and a support tube. The lug 308c is installed at the bottom of the support rod, and the support tube is hinged within the hinge seat 205.

[0058] Specifically, there is a pair of support rods and a single support tube, both of which are distributed between the two connecting rods, and the ear piece 308c is located at the bottom of the previous support rod.

[0059] It should be noted that the connecting frame 308 with this structure is simple in structure, easy to manufacture, and makes it easier to install the landing gear 307.

[0060] Furthermore, the support frame 206 includes a flange 206b disposed at the bottom of the support frame 206a. The four corners of the support frame 206a are connected to the flange via connecting rods 206c. The flange 206b is connected to the connecting flange 203 by bolts. The support frame 206a is arranged at an angle, with its front end lower than its rear end.

[0061] Specifically, the support frame 206 is a frame structure made of square tubes welded together, and the connecting rod 206c is also fixed by welding. The flange 206b is designed to facilitate the installation and replacement of different models of support frames 206, so as to realize modular testing.

[0062] Furthermore, the three-component force sensor assembly 4 includes a signal acquisition unit 403 disposed between the upper wall plate 401 and the lower wall plate 402. The signal acquisition unit 403 is used to transmit the detected pressure. The upper wall plate 401 is fixed to the bottom of the support frame, and the lower wall plate 402 is fixed to the transport platform 1.

[0063] Specifically, the signal acquisition unit 403 mainly functions to detect pressure and transmit pressure data, including a pressure sensor and a wireless transmission module, while the upper wall plate 401 and the lower wall plate 402 mainly serve as supports and connections.

[0064] The invention will be further explained below with reference to specific experimental methods.

[0065] like Figure 9 As shown, the velocity coordinate system of the unmanned tiltrotor aircraft system Ox v y v z v Definition and three-component force sensor output force coordinate system Ox s y s z s definition.

[0066] like Figure 10 As shown, the thrust T (forward is positive) at both ends of the unmanned tiltrotor aircraft can be measured by the thrust sensor 309a installed on the rotor system. The force X in the three directions of the i-th three-component force sensor can be measured by the four three-component force sensors 4A, 4B, 4C, and 4D. 4i Y 4i Z 4i (i represents A, B, C, and D, according to the coordinate system) Ox s y s z s (The positive direction is defined as the same as the positive direction of the coordinate axis). The data to be obtained during the experiment is the axial force F acting on the unmanned tiltrotor aircraft. A Normal force F N And pitching moment M Z (The sign of force and torque depends on the coordinate system) Ox v y v z v (Definition); The projection point of the center of gravity of an unmanned tiltrotor aircraft during testing is x. CGThe three force sensors 4A and 4C are located at distances of L1 and L2 from this point in the pitch plane, respectively, while AC and BD are located at distance L3. The distance between the center of mass of the unmanned tiltrotor aircraft and the sensor plane is L4.

[0067] like Figure 11 As shown, a test method for measuring the aerodynamic performance of an unmanned tiltrotor aircraft includes the following steps:

[0068] 1) First, an experiment was conducted with a speed V without an unmanned tiltrotor aircraft to obtain the output information of the three-component force sensor, which was defined as state point data.

[0069] 2) The test was conducted again with a speed V-belt unmanned tiltrotor aircraft to obtain the three-component force sensor output information, which was defined as 2-state point data;

[0070] 3) Subtract the data from the data at state point 1 from the data at state point 2 to obtain the net force data, which is defined as the net force state point data. For example, X 4A = X 4A (2) -X 4A (1) ;

[0071] ;

[0072] 4) In the pitch plane, the direction of the plumb bob can be determined using the force balance formula:

[0073] ;

[0074] 5) In the pitch plane, the horizontal direction can be determined using the force balance formula:

[0075] ;;

[0076] 6) In the pitch plane, the following can be obtained using the moment balance formula:

[0077] .

[0078] Due to the influence of uneven road surface, natural wind and other external forces, the measured data is not very stable. Therefore, it is necessary to collect test data continuously and multiple times at the same forward speed, select the more stable data information, screen and determine the required values ​​through the 3σ rule, and calculate the average to obtain the final value.

[0079] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A test apparatus for measuring the aerodynamic performance of an unmanned tiltrotor aircraft, characterized in that, include: The transport platform (1) is used to transport the unmanned tiltrotor aircraft (3) to be tested and can complete the constant speed linear motion back and forth in a closed road. The transport platform (1) is equipped with a shock absorber (102) to isolate the vehicle body vibration. The shock absorber (102) is equipped with a test stand (2). The test bench (2) includes a support bench. The lower end of the support bench is mounted on a shock absorber (102) via four three-component force sensor assemblies (4). The upper end of the support bench is provided with a support frame (206). The support frame (206) is connected to the landing gear (307) of the unmanned tiltrotor aircraft (3) under test. The rear part of the landing gear (307) is hinged to the support frame (206). The front part of the landing gear (307) is connected to the support frame (206) via an actuator (204). The actuator (204) is used to change the pitch attitude of the unmanned tiltrotor aircraft (3) under test. An unmanned tiltrotor aircraft (3) with a tension sensor (309a) installed on its rotor system (303); The support frame includes a hydraulic cylinder (202) installed on a high platform (201). The piston rod of the hydraulic cylinder (202) is fixedly connected to the bottom of the support frame (206) through a connecting flange (203). The four three-component force sensor assemblies (4) are installed at the four corners of the bottom surface of the high platform (201). The support frame (206) has a pair of hinge seats (205) at the rear top position, and a pair of actuators (204) are hinged at the front top position of the support frame (206). The landing gear (307) is mounted on the connecting frame (308). The rear part of the connecting frame (308) is hinged in the hinge seats (205), and the front part of the connecting frame (308) is hinged to the actuators (204). The connecting frame (308) comprises a truss (308a), a clamp (308b), and a lug (308c). The truss (308a) includes a pair of connecting rods for connecting the landing gear (307). The connecting rods are provided with arc-shaped grooves that mate with the landing gear (307). The landing gear (307) is fixedly connected to the connecting rods via the clamp (308b). The two connecting rods are connected via a support rod and a support tube. The lug (308c) is installed at the bottom of the support rod. The support tube is hinged in the hinge seat (205). The support frame (206) includes a flange (206b) disposed at the bottom of the support frame (206a). The four corners of the support frame (206a) are connected to the flange (206b) by connecting rods (206c). The flange (206b) is connected to the connecting flange (203) by bolts. The support frame (206a) is arranged at an angle, with its front end lower than its rear end.

2. The test apparatus for measuring the aerodynamic performance of an unmanned tiltrotor aircraft (3) according to claim 1, characterized in that, The three-component force sensor assembly (4) includes a signal acquisition unit (403) disposed between the upper wall plate (401) and the lower wall plate (402). The signal acquisition unit (403) is used to transmit the detected pressure. The upper wall plate (401) is fixed to the bottom of the support frame, and the lower wall plate (402) is fixed to the transport platform (1).

3. A test method for measuring the aerodynamic performance of an unmanned tiltrotor aircraft, using the test apparatus described in claim 1 or 2, characterized in that, Includes the following steps: Step 1) Install the test bench onto the transport platform; Step 2) The unloaded transport platform moves forward at a speed V to conduct the test and obtains the pressure information detected by the three-component force sensors, which is recorded as the first state point data; Step 3) Install the unmanned tiltrotor aircraft onto the test bench and adjust the angle of attack. α The carrier platform advances again at a speed of V to conduct the test, and obtains the pressure information detected by the three-component force sensor, which is recorded as the second state point data. Step 4) Subtract the first state point data from the second state point data to obtain the net force data X. 4A X 4B X 4C X 4D、 Y 4A Y 4B Y 4C Y 4D ; Step 5) Calculate the axial force F A Normal force F N And pitching moment M Z : Wherein, 4A, 4B, 4C, and 4D represent four three-component force sensors, X, Y, and Z are the force components detected by the three-component force sensors in three directions, T is the thrust of the two rotors of the unmanned tiltrotor aircraft, L1 is the distance between the center of mass of the unmanned tiltrotor aircraft and 4A in the length direction of the three-component force sensors 4A and 4C, L2 is the distance between the center of mass of the unmanned tiltrotor aircraft and 4B in the length direction of the three-component force sensors 4B and 4D, and L4 is the distance between the center of mass of the unmanned tiltrotor aircraft and the sensor plane.

Images