A five-degree-of-freedom virtual flight test device based on motion compensation

Abstract

The application provides a five-degree-of-freedom virtual flight test device based on motion compensation, wherein a test model of the device can complete three-axis rotation motion with the help of a three-degree-of-freedom hinge, the test model and an abdominal support strut can move up and down along the axial direction of a three-pronged suspension support to complete the release of the heave degree of freedom, and the test model and the three-pronged suspension support can realize lateral undamped motion under the support of a pneumatic suspension bearing, so as to achieve the purpose of releasing the lateral translation degree of freedom. A parallel six-degree-of-freedom mechanism base at the bottom is responsible for motion compensation of the lateral translation, heave, roll and pitch degrees of freedom, and based on the above structure, the device can realize the five-degree-of-freedom coupled motion test capability except the forward and backward motion. The realization of the above functions has important significance for improving the restoration capability of the virtual flight test of a wind tunnel to the real dynamic characteristics of an aircraft model.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel virtual flight testing technology for aircraft, and in particular to a five-degree-of-freedom virtual flight testing device based on motion compensation. Background Technology

[0002] Wind tunnel virtual flight testing generally refers to a testing method in which an aircraft is tested in a wind tunnel after one or more degrees of freedom are released. This includes typical three-degree-of-freedom virtual flight tests implemented using a three-degree-of-freedom rotational hinge, and wind tunnel free-flight tests with six degrees of freedom. However, wind tunnel free-flight tests are difficult to control and have low fault tolerance, thus limiting their application. This virtual flight testing method is classified as wind tunnel dynamic testing. Unlike forced dynamic testing, wind tunnel virtual flight testing mainly refers to free dynamic testing of aircraft models. It is often used in research on aircraft control surface excitation response, flight controllability verification, and flight parameter identification, and is a comprehensive testing method integrating aerodynamics, flight mechanics, and flight control.

[0003] In recent years, four-degree-of-freedom (DOF) testing methods have emerged, further releasing heave freedom on top of the three rotational degrees of freedom. Aside from the less practical six-DOF wind tunnel free-flight, virtual flight with four DDFs is currently a relatively advanced testing technique. By considering heave motion, the longitudinal motion characteristics of the test model are simulated more realistically, exhibiting significant differences in frequency and damping ratio compared to models with only three rotational degrees of freedom. Generally speaking, the more DDFs released, the higher the level of dynamic characteristic testing of the model. Six-DOF wind tunnel free-flight testing is undoubtedly the most complete method for reproducing flight dynamics, but this method places high demands on wind tunnel size, flight control mechanisms, flight safety measures, and model design, resulting in a low tolerance for error and thus not being widely adopted.

[0004] In conclusion, while methods that allow for some degrees of freedom remain the primary testing approach in the field of virtual flight testing, increasing the number of degrees of freedom to improve testing accuracy and simulation realism is a significant development trend. Therefore, there is an urgent need for a virtual flight testing device that can effectively increase degrees of freedom and improve testing results to meet the growing testing demands of aircraft development and promote the further development of aerospace technology. Summary of the Invention

[0005] The purpose of this invention is to provide a five-degree-of-freedom virtual flight test device based on motion compensation, which solves the problem of the small degree-of-freedom range in conventional virtual flight tests.

[0006] This invention provides a five-degree-of-freedom virtual flight test device based on motion compensation, comprising a parallel six-degree-of-freedom mechanism base, a three-pronged suspension support, a test model, and a measurement and control computer. A drive controller is mounted on the parallel six-degree-of-freedom mechanism base. A pneumatic suspension bearing is mounted on the top of the parallel six-degree-of-freedom mechanism base, and the three-pronged suspension support is slidably inserted into the pneumatic suspension bearing. A longitudinally extending abdominal support rod is installed on the three-pronged suspension support. The test model is mounted on the top of the abdominal support rod via a three-degree-of-freedom hinge. An angle sensor is fixedly mounted on the test model. A lateral displacement sensor is fixedly mounted on the top of the parallel six-degree-of-freedom mechanism base, and a heave displacement sensor is mounted on the bottom of the abdominal support rod. The angle sensor, lateral displacement sensor, heave displacement sensor, and drive controller are all signal-connected to the measurement and control computer.

[0007] Furthermore, two bearing supports are fixedly installed on the base of the parallel six-degree-of-freedom mechanism, and pneumatic suspension bearings are fixedly installed on each bearing support. The axes of the pneumatic suspension bearings are parallel to each other, and two pneumatic suspension bearings are fixedly installed at intervals along the axial direction on one of the bearing supports.

[0008] Furthermore, the three-pronged suspension support includes a main support tube, and three parallel sliding rods are provided on the side of the main support tube, one of which is located on the opposite side of the other two sliding rods, and each of the sliding rods is slidably inserted into the corresponding pneumatic suspension bearing.

[0009] Furthermore, linear bearings are installed at both ends of the main support tube, and the abdominal support rod is sleeved inside the linear bearings.

[0010] Furthermore, the sum of the length of the slide rod and the outer diameter of the main support tube is greater than the distance between the two bearing supports.

[0011] Furthermore, the axes of the two slide rods located at the bottom end coincide.

[0012] Furthermore, the installation height of the lateral displacement sensor coincides with the height position of the slide rod located at the bottom.

[0013] Furthermore, the three-pronged suspension support is made of carbon fiber material.

[0014] Furthermore, the mass of the three-pronged suspension support is less than 10% of the mass of the test model.

[0015] The beneficial effects of this technical solution are as follows: the test model of this device can complete three-axis rotational motion with the help of a three-degree-of-freedom hinge, and the test model and the belly support rod can move up and down along the axis of the three-pronged suspension bracket to release the heave degree of freedom. Furthermore, the test model and the three-pronged suspension bracket, supported by aerodynamic suspension bearings, can achieve undamped lateral motion, thereby releasing the lateral displacement degree of freedom. The parallel six-degree-of-freedom mechanism base at the bottom is responsible for motion compensation of the lateral displacement, heave, roll, and pitch degrees of freedom. Based on the above structure, this device can achieve coupled motion testing capabilities for the remaining five degrees of freedom, excluding forward and backward motion. The realization of these functions is of great significance for improving the ability of wind tunnel virtual flight tests to reproduce the real dynamic characteristics of aircraft models. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the planar structure of this invention.

[0018] Figure 2 A schematic diagram of the lateral movement and compensation of the model of this invention.

[0019] Figure 3 A schematic diagram of the heave motion and compensation of the model of this invention.

[0020] Figure 4 A schematic diagram of the rolling motion and compensation of the model of this invention.

[0021] Figure 5 A schematic diagram of the pitch motion and compensation of the model of this invention.

[0022] Explanation of reference numerals in the attached drawings: 1-Three-pronged suspension support, 2-Abdominal support rod, 3-Three-degree-of-freedom hinge, 4-Pneumatic suspension bearing, 5-Bearing support, 6-Parallel six-degree-of-freedom mechanism base, 7-Linear bearing, 8-Angle sensor, 9-Lateral displacement sensor, 10-Heave displacement sensor, 11-Experimental model, 12-Measurement and control computer, 13-Drive controller. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Example 1

[0027] like Figures 1-5As shown, the present invention provides a five-degree-of-freedom virtual flight test device based on motion compensation, including a parallel six-degree-of-freedom mechanism base 6, a three-pronged suspension support 1, a test model 11, and a measurement and control computer 12. A drive controller 13 is provided on the parallel six-degree-of-freedom mechanism base 6. Two bearing supports 5 are fixedly installed on the parallel six-degree-of-freedom mechanism base 6, and pneumatic suspension bearings 4 are fixedly installed on each bearing support 5. The axes of the pneumatic suspension bearings 4 are parallel to each other. Two pneumatic suspension bearings 4 are fixedly installed at intervals along the axial direction on one bearing support 5, and one pneumatic suspension bearing 4 is fixedly installed on the other bearing support 5. The three-pronged suspension bracket 1 is slidably inserted into the pneumatic suspension bearing 4. Specifically, the three-pronged suspension bracket 1 includes a main support tube, on the side of which are three parallel sliding rods. One sliding rod is located on the opposite side of the other two sliding rods, and the axes of the two sliding rods at the bottom end coincide. Each sliding rod is slidably inserted into its corresponding pneumatic suspension bearing 4, allowing for undamped lateral sliding under the support of the pneumatic suspension bearing 4, thus releasing the model's degrees of freedom. The sum of the length of the sliding rod and the outer diameter of the main support tube is greater than the distance between the two bearing supports 5 to prevent the three-pronged suspension bracket 1 from detaching from the pneumatic suspension bearing 4.

[0028] A longitudinally running support rod 2 is installed on the main support tube of the three-pronged suspension support 1. The installation structure is as follows: linear bearings 7 are installed at both ends of the main support tube, and the abdominal support rod 2 is sleeved inside the linear bearings 7. With the help of the linear bearings 7, the test model 11 and the abdominal support rod 2 can move up and down along the axial direction of the main support tube, thereby releasing the model's heave degree of freedom. The bottom parallel six-degree-of-freedom structure is mainly used to support the above-mentioned structure, and on the other hand, it is used to provide motion compensation for each degree of freedom, thereby expanding the range of motion of each degree of freedom.

[0029] The test model 11 is mounted on the top of the abdominal support rod 2 via a three-degree-of-freedom hinge 3. With the help of the three-degree-of-freedom hinge 3, the test model 11 can realize virtual flight including three-degree-of-freedom rotational motions such as pitch, yaw, and roll. The three-degree-of-freedom hinge 3 is existing technology and will not be described in detail here.

[0030] An angle sensor 8 is fixedly installed on the test model 11. A lateral displacement sensor 9 is fixedly installed on the top of the base 6 of the parallel six-degree-of-freedom mechanism. The installation height of the lateral displacement sensor 9 coincides with the height of the sliding rod at the bottom. A heave displacement sensor 10 is installed at the bottom of the abdominal support rod 2. The angle sensor 8, lateral displacement sensor 9, heave displacement sensor 10, and drive controller 13 are all connected to the measurement and control computer 12.

[0031] During the wind tunnel virtual flight test, according to Figure 2As shown, when the model is subjected to aerodynamic forces to the left or right, the model and the triangular suspension support 1 can move laterally to the left or right as a whole, supported by three pneumatic suspension bearings 4. At this time, the displacement sensor measures the displacement of the triangular suspension support 1 relative to the parallel six-degree-of-freedom upper platform in real time. This displacement is transmitted to the measurement and control computer 12 through a signal line. The measurement and control computer 12 calculates the movement of the parallel six-degree-of-freedom mechanism based on this displacement and sends the movement command to the drive controller 13 of the parallel six-degree-of-freedom mechanism base 6 through a communication line, thereby driving the parallel six-degree-of-freedom mechanism base 6 to move left and right in real time in coordination with the triangular suspension support 1 to compensate for lateral displacement and achieve the purpose of extending the lateral displacement stroke. Since the model and the triangular suspension support 1 move simultaneously, the weight of the support itself is added to the mass of the model. In order to minimize the influence of the mass of the support itself on the dynamic characteristics of the model, the triangular suspension support 1 here is made of all carbon fiber material, and the mass of the support is controlled within 10% of the mass of the model.

[0032] according to Figure 3 As shown, when the model's lift changes, it may move upward or downward. At this time, under the constraint of the linear bearing 7, the model and the abdominal support rod 2 can move up and down simultaneously along the axis of the main support tube. At this time, the heave displacement sensor 10 measures the heave displacement of the abdominal support rod 2 in real time. This displacement signal is sent to the measurement and control computer 12 through the signal line. The measurement and control computer 12 calculates the heave displacement of the parallel six-degree-of-freedom mechanism and sends the movement command to the drive controller 13 of the parallel six-degree-of-freedom mechanism at the bottom through the communication line. This drives the base 6 of the parallel six-degree-of-freedom mechanism to move up and down in real time in coordination with the model, compensating for the model's heave motion and extending the model's heave freedom stroke.

[0033] according to Figure 4 As shown, when the model rolls under aerodynamic force, the angle sensor 8 located inside the model measures the roll angle of the model. The roll angle signal is transmitted to the measurement and control computer 12 through the signal line. The computer calculates the corresponding displacement of the parallel six-degree-of-freedom mechanism base 6 based on the angle value and sends it to the drive controller 13, thereby driving the six-degree-of-freedom mechanism to cooperate with the model to perform roll motion, so as to compensate for the model's roll and extend the roll degree of freedom stroke.

[0034] Similarly, according to Figure 5 As shown, when the model pitches under the action of aerodynamic force, the angle sensor 8 located inside the model measures the pitch angle of the model. The pitch angle signal is transmitted to the measurement and control computer 12 through the signal line. The computer calculates the corresponding displacement of the parallel six-degree-of-freedom mechanism base 6 based on the angle value. The displacement is sent to the drive controller 13 through the communication line, thereby driving the parallel six-degree-of-freedom mechanism base 6 to cooperate with the model to perform pitching motion, so as to compensate for the pitch angle of the model and extend the pitch freedom stroke.

[0035] In summary, this solution first achieves five degrees of freedom motion functions, including lateral movement, heave, roll, pitch, and yaw. Secondly, it compensates for the motion of the four degrees of freedom (lateral movement, heave, roll, and pitch) through a parallel six-degree-of-freedom mechanism base 6, thus extending the travel range of the aforementioned four degrees of freedom (virtual flight test technology can achieve a yaw freedom range of up to 360° in an unlimited position, therefore there is no need to consider the travel extension issue of the yaw freedom).

[0036] Compared to previous four-degree-of-freedom virtual flight testing techniques, this invention cleverly utilizes aerodynamic suspension bearing 4 to achieve undamped lateral movement of the model. This capability is significant for experimentally reproducing the lateral dynamic characteristics of an aircraft, such as simulating the Dutch roll mode that couples yaw, roll, and lateral movement. Furthermore, based on the aforementioned five-degree-of-freedom motion, the auxiliary compensation motion of a parallel six-degree-of-freedom mechanism extends the motion range of four of the degrees of freedom. This feature facilitates dynamic testing of large-scale motions for single-degree-of-freedom applications.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A five-degree-of-freedom virtual flight test device based on motion compensation, characterized in that, The device includes a parallel six-degree-of-freedom mechanism base, a three-pronged suspension support, a test model, and a measurement and control computer. The parallel six-degree-of-freedom mechanism base is equipped with a drive controller. A pneumatic suspension bearing is mounted on the top of the parallel six-degree-of-freedom mechanism base, and the three-pronged suspension support is slidably inserted into the pneumatic suspension bearing. A longitudinally extending abdominal support rod is installed on the three-pronged suspension support. The test model is mounted on the top of the abdominal support rod via a three-degree-of-freedom hinge. An angle sensor is fixedly installed on the test model. A lateral displacement sensor is fixedly installed on the top of the parallel six-degree-of-freedom mechanism base, and a heave displacement sensor is installed at the bottom of the abdominal support rod. The angle sensor, lateral displacement sensor, heave displacement sensor, and drive controller are all connected to the measurement and control computer. Two bearing supports are fixedly installed on the base of the parallel six-degree-of-freedom mechanism. Each bearing support is fixedly installed with a pneumatic suspension bearing. The axes of the pneumatic suspension bearings are parallel to each other. Two pneumatic suspension bearings are fixedly installed at intervals along the axial direction on one of the bearing supports. The three-pronged suspension support includes a main support tube, and three parallel sliding rods are provided on the side of the main support tube. One of the sliding rods is located on the opposite side of the other two sliding rods, and each sliding rod is slidably inserted into the corresponding pneumatic suspension bearing.

2. The five-degree-of-freedom virtual flight test device based on motion compensation according to claim 1, characterized in that, Linear bearings are installed at both ends of the main support tube, and the abdominal support rod is sleeved inside the linear bearings.

3. The five-degree-of-freedom virtual flight test device based on motion compensation according to claim 1, characterized in that, The sum of the length of the slide rod and the outer diameter of the main support tube is greater than the distance between the two bearing supports.

4. The five-degree-of-freedom virtual flight test device based on motion compensation according to claim 1, characterized in that, The axes of the two slide rods located at the bottom end coincide.

5. The five-degree-of-freedom virtual flight test device based on motion compensation according to claim 1, characterized in that, The installation height of the lateral displacement sensor coincides with the height position of the slide rod located at the bottom.

6. The five-degree-of-freedom virtual flight test device based on motion compensation according to claim 1, characterized in that, The three-pronged suspension support is made of carbon fiber.

7. The five-degree-of-freedom virtual flight test device based on motion compensation according to claim 6, characterized in that, The mass of the three-pronged suspension support is less than 10% of the mass of the test model.

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