A sink-float-pitch support mechanism and method for wind tunnel model dynamic testing

Abstract

The application relates to a sink-float pitching support mechanism and method for wind tunnel model dynamic testing, and belongs to the technical field of wind tunnel testing. The application solves the technical problem that the model support mechanism in the wind tunnel causes the distortion of measurement results and the loss of real reference value. The application comprises a main body frame, a sliding block unit and a passive buffer device, the passive buffer device is installed on the main body frame, and the sliding block unit is slidingly arranged on the main body frame. The sliding block unit of the sink-float pitching support mechanism and method for wind tunnel model dynamic testing is integrated with a magnetic component design, the friction of the sink-float movement is extremely small, a single model connecting shaft structure ensures the purity of the pitching movement, the interference of the support system on the real dynamic characteristics of the model is minimized, and the movement accuracy and fidelity of the model during the test in the wind tunnel are high.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel testing technology, specifically relating to a buoyancy and pitch support mechanism and method for dynamic testing of wind tunnel models. Background Technology

[0002] In the study of gust response, load mitigation, and control law verification of large flexible aircraft, it is necessary to realize the free flight state of the model in a wind tunnel in order to accurately measure the coupled dynamic response of its rigid body modes and elastic modes. Multi-degree-of-freedom cable-stayed systems are prone to inducing dangerous low-frequency oscillations in models with large mass, high inertia, high aspect ratio, or statically unstable layouts. Furthermore, cable constraints introduce parasitic frequencies and damping, severely interfering with or even obscuring the true dynamic characteristics of the airframe's elastic modal response and low-frequency rigid modes, which are of interest and occur in close frequency bands. In addition, multivariable strongly coupled control systems are extremely complex, and their reliability is difficult to guarantee. Telescopic strut support systems, on the other hand, introduce excessive additional mass, which directly couples into the model's dynamic system, severely altering its inertial characteristics and distorting the measured modal frequencies and damping ratios, rendering them unreliable.

[0003] Therefore, this application proposes a buoyancy and pitch support mechanism and method for dynamic testing of wind tunnel models to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem of distorted measurement results caused by the support mechanism of the model in the wind tunnel, thus rendering the results unreliable. A brief overview of this invention is provided below to offer a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0005] The technical solution of the present invention:

[0006] Option 1: A heave-pitch support mechanism for dynamic testing of wind tunnel models, comprising a main frame, a slider unit and a passive buffer device, wherein the passive buffer device is installed on the main frame and the slider unit is slidably mounted on the main frame.

[0007] The main frame includes columns, column connecting plates, and column diagonal braces. The upper and lower ends of the columns are connected to the column diagonal braces through the column connecting plates. The columns are connected to the top plate and floor of the wind tunnel test section through the column diagonal braces. A set of passive buffer devices is installed at the top and bottom of the columns respectively.

[0008] The slider unit is arranged on the outside of the column and is connected to the column via a magnetic component. A buoyancy brake is installed on the slider unit, and a pair of opening / closing calipers are symmetrically installed on it. Each caliper includes an upper caliper and a lower caliper, which are hinged to the slider unit via caliper pins. The opening / closing calipers are connected to a pitch limit block guide seat via caliper pins. The pitch limit block guide seat is fitted onto the pitch limit block, which is connected to a lead screw. The lead screw is mounted on the slider unit via a lead screw mounting seat and is driven by a drive source. A pitch lock pin is installed on the slider unit, located on the inside of the opening / closing calipers. A pitch emergency lock actuator is installed on the slider unit and connected to the opening / closing calipers via caliper pins. The model is mounted on the slider unit via a model connecting shaft and is connected to a model connecting block. The opening / closing calipers limit the pitch angle of the model via the model connecting block.

[0009] Furthermore, the passive buffer device includes a limiting bracket, an impact mitigation component, and an impact mitigation rod. The limiting bracket is installed at the upper and lower ends of the column via a column connecting plate. The impact mitigation component and the impact mitigation rod are installed on the limiting bracket, with one end of the impact mitigation rod passing through the limiting bracket and the column connecting plate.

[0010] Furthermore, the impact mitigation component is a limiting spring or a damper.

[0011] Furthermore, the slider unit includes a front slider frame, a right slider frame, a rear slider frame, and a left slider frame. The front slider frame, the right slider frame, the rear slider frame, and the left slider frame are connected in sequence to form a frame surrounding the outside of the column. Magnetic components are respectively installed on the inner sides of the front slider frame, the right slider frame, the rear slider frame, and the left slider frame. Opening and closing calipers and pitch lock pins are respectively installed on the right slider frame and the left slider frame. The model connecting block, the pitch emergency lock actuator, and the lead screw mounting base are installed on the front slider frame.

[0012] Furthermore, a sinking and floating brake is installed on the right frame of the slider. The active end brake beam is installed on the right frame of the slider through a brake pin and a brake pin fastening nut. The driven end brake beam is installed on the left frame of the slider through a brake pin and a brake pin fastening nut. The two brake pins are connected through a brake pin sleeve. The actuating end of the sinking and floating brake passes through the active end brake beam and is connected to the active end brake pad. A driven end brake pad is installed on the driven end brake beam. The active end brake pad and the driven end brake pad are respectively arranged on both sides of the column.

[0013] Furthermore, limiting platforms are machined on the right and left frames of the slider, respectively.

[0014] Furthermore, a pitch impact mitigation module is installed on the model connecting block. The pitch impact mitigation module includes a pitch buffer spring pressure plate, a pitch buffer spring pressure block, and a pitch buffer spring. The pitch buffer spring is pressed tightly into the inside of the model connecting block by the pitch buffer spring pressure plate and the pitch buffer spring pressure block. The pitch impact mitigation module is longitudinally aligned with the opening and closing caliper.

[0015] Option 2: A method for using a heave-pitch support mechanism for dynamic testing of wind tunnel models, which is based on the heave-pitch support mechanism for dynamic testing of wind tunnel models described in Option 1, and includes the following steps:

[0016] Step 1: Preparation and installation. Fix the column to the center of the wind tunnel test section using the column diagonal bracing rod. Install the slider unit on the column. Install the model on the slider unit using the model connecting shaft and model connecting block.

[0017] Step 2: Pre-test setup. With the model in pitch lock and buoyancy brake states, control the drive source to drive the lead screw. With the rotation of the lead screw, control the position of the pitch limit block and the pitch limit block guide seat, set the range of motion of the model pitch angle, and check the function of the pitch emergency lock actuator and the buoyancy brake.

[0018] Step 3: Model release and trimming. Start the wind tunnel to reach the preset test dynamic pressure. First, release the pitch emergency lock actuator and simultaneously activate the model pitch attitude controller to ensure that the model is physically locked in the vertical direction and establishes attitude stability. Then, release the buoyancy brake and simultaneously activate the model vertical position controller. On the basis of controllable model attitude, give it vertical motion capability. The model takes off smoothly on the impact mitigation rod. The model pitch attitude controller and the model vertical position controller control the model to fly to the center position of the test section for trimming, simulating free flight.

[0019] Step 4: Dynamic testing and safety monitoring. Execute the test task and monitor the model's buoyancy position, pitch attitude, buoyancy speed, and pitch rate in real time. When any parameter exceeds the preset threshold, the safety sequence is automatically triggered, the buoyancy brake is activated to decelerate, and the pitch emergency lock actuator is commanded to control the opening and closing calipers to close inward and clamp the model connecting block, forcibly fixing the model at a neutral angle of attack.

[0020] Step 5: Model landing and recovery. After the test, the model is guided to the lower end to land on the passive buffer device by the position controller, or the braking and locking are directly triggered to reduce the wind tunnel dynamic pressure and allow the model to sink smoothly.

[0021] Furthermore, in step four, after the opening and closing calipers clamp the model connecting block, they continue to move inward until the upper and lower calipers contact and press against the pitch lock stop pin respectively. At this time, the upper caliper, lower caliper, model connecting block and pitch lock stop pin form a statically determinate structure, eliminating all movement gaps. The pitch degree of freedom of the model is completely physically locked, and the model, opening and closing calipers and pitch lock stop pin become a rigid whole.

[0022] Furthermore, in step four, when the model reaches its vertical travel limit, the passive buffer device is triggered and works in conjunction with the buoyancy brake to bring the model to a safe stop with a small impact load.

[0023] The present invention has the following beneficial effects:

[0024] 1. The present invention provides a buoyancy and pitch support mechanism for dynamic testing of wind tunnel models. The slider unit integrates a magnetic component design to minimize the friction of the buoyancy motion, and the single model connecting shaft structure ensures the purity of the pitch motion, minimizing the interference of the support system on the real dynamic characteristics of the model; thus enabling the model to have high motion accuracy and fidelity during wind tunnel testing.

[0025] 2. The buoyancy and pitch support mechanism for dynamic testing of wind tunnel models of the present invention has high safety. The support mechanism integrates multiple active and passive safety designs such as active braking, locking and passive impact mitigation, making it possible to test under extreme unstable conditions such as negative static stability of the model, and greatly protecting the model and wind tunnel facilities.

[0026] 3. The buoyancy and pitch support mechanism for dynamic testing of wind tunnel models of the present invention has high versatility. The concept of this support system is not limited to a specific model and can be widely applied to various aeroelastic free flight wind tunnel tests, providing a key experimental platform for studying the gust response, flutter, and active control of large flexible aircraft.

[0027] 4. The buoyancy and pitch support mechanism of the present invention for dynamic testing of wind tunnel models provides the model with pure motion of two symmetrical degrees of freedom, pitch and buoyancy, under the premise of strictly constraining asymmetric degrees of freedom and minimal mechanical interference. It also incorporates multiple safety redundancies, both active and passive, to ensure that the model can achieve "controllable free flight" even under extreme conditions such as negative static stability. It will provide a comprehensive test platform for high-risk aerodynamic servo-elasticity tests in wind tunnels, especially for gust response suppression and relaxed static stability flight. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall assembly of a buoyancy and pitch support mechanism used for dynamic testing of wind tunnel models.

[0029] Figure 2 This is a schematic diagram of the main framework structure;

[0030] Figure 3 This is a schematic diagram of a passive buffer device.

[0031] Figure 4 This is a schematic diagram of the overall assembly of the slider unit;

[0032] Figure 5 This is the right view of the slider unit;

[0033] Figure 6 This is a top view of the slider unit;

[0034] Figure 7 This is a schematic diagram showing the relationship between the pitch limit block, the pitch limit block guide seat, and the lead screw;

[0035] Figure 8 This is a schematic diagram of the model's pitch angle limit.

[0036] Figure 9 This is a schematic diagram of the buoyancy brake in the unbraked state;

[0037] Figure 10 This is a schematic diagram of the buoyancy brake's braking state;

[0038] Figure 11 This is a flowchart illustrating the steps of using a buoyancy and pitch support mechanism for dynamic testing of wind tunnel models.

[0039] Figure 12 This is the main view of the model connection block.

[0040] In the diagram: 1-Pitch buffer spring pressure plate, 2-Pitch buffer spring pressure block, 3-Pitch buffer spring, 4-Model connecting block, 5-Pitch emergency lock actuator, 6-Pitch limit block, 7-Pitch limit block guide seat, 8-Screw mounting seat, 9-Slider front frame, 10-Drive source, 11-Screw, 12-Upper caliper, 13-Lower caliper, 14-Caliper pin, 15-Magnetic component, 16-Pitch lock pin, 17-Model connecting shaft, 18-Slider right frame, 1 9-Slider rear frame, 20-Slider left frame, 21-Brake pin fastening nut, 22-Brake pin, 23-Brake pin sleeve, 24-Floating brake, 25-Active end brake beam, 26-Active end brake pad, 27-Driven end brake pad, 28-Driven end brake beam, 29-Column, 30-Column connecting plate, 31-Column diagonal brace, 32-Limit bracket, 33-Impact damping component, 34-Impact damping rod, 35-Limit platform. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0042] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections (i.e., non-detachable connections) include, but are not limited to, conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include, but are not limited to, conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0043] Example 1, combined with Figures 1-12 This embodiment describes a buoyancy and pitch support mechanism for dynamic testing of wind tunnel models, comprising a main frame, a slider unit, and a passive buffer device. The passive buffer device is mounted on the main frame, and the slider unit is slidably mounted on the main frame.

[0044] The main frame's columns 29 are high-strength steel beams with rectangular cross-sections, fixed to the wind tunnel's top and bottom plates by eight diagonal braces 31. Columns 29 provide lateral, longitudinal, and torsional stiffness, strictly constraining the model's roll, horizontal, lateral translation, and yaw degrees of freedom. Their natural frequencies are much higher than the model's elastic modes, avoiding dynamic coupling interference. The diagonal braces 31 connect the upper and lower ends of columns 29 via column connecting plates 30, which are used to fix columns 29, making them a reliable inertial reference standard.

[0045] A passive buffer device is installed at the top and bottom of the column 29. The passive buffer device is connected to the column 29 through the column connecting plate 30. The limiting bracket 32 ​​of the passive buffer device is installed on the column 29 through the column connecting plate 30. The limiting bracket 32 ​​is equipped with an impact mitigation component 33, which is a limiting spring or a damper. The limiting bracket 32 ​​is also equipped with an impact mitigation rod 34. When the slider unit approaches the stroke limit, it will contact the impact mitigation rod 34. The impact mitigation rod 34 absorbs the remaining kinetic energy through the parallel impact mitigation component 33 and converts it into potential energy to achieve a soft landing of the model.

[0046] The slider unit consists of a front slider frame 9, a right slider frame 18, a rear slider frame 19, and a left slider frame 20 connected sequentially. These frames, when connected, form a frame that fits over the outside of the column 29. Each of the front slider frame 9, right slider frame 18, rear slider frame 19, and left slider frame 20 contains a magnetic component 15. Under magnetic force, the right slider frame 18 and left slider frame 20 bear the lateral force, yaw moment, and rolling moment of the model, while the front slider frame 9 and rear slider frame 19 bear the resistance of the model. The magnetic component 15 allows the slider unit to slide vertically up and down along the column 29 with extremely low friction. The model is mounted on the slider unit via bearing seats on both sides of its central body and a model connecting shaft 17. During the experiment, the model can freely pitch and rotate around the model connecting shaft 17.

[0047] To control the pitch angle range of the model, a pair of opening and closing calipers are installed on the right frame 18 and the left frame 20 of the slider, respectively. The opening and closing calipers include an upper caliper 12 and a lower caliper 13. The tail ends of the upper caliper 12 and the lower caliper 13 are hinged to the right frame 18 and the left frame 20 of the slider via caliper pins 14. The front ends of the upper caliper 12 and the lower caliper 13 are connected to the pitch limit block guide seat 7 via caliper pins. The pitch limit block guide seat 7 is fitted onto the pitch limit block. On the 6th, the pitch limit block 6 is connected to the lead screw 11 through the lead screw nut. The upper half and lower half of the lead screw 11 have opposite threads. The lead screw 11 is mounted on the front frame 9 of the slider through the lead screw mounting seat 8. The drive source 10 drives the lead screw 11 to rotate, which drives the pitch limit blocks 6 at the upper and lower ends of the lead screw 11 to open and close synchronously. The allowable range of motion of the model pitch angle can be set remotely and steplessly through the remote control drive source 10. This adjustment is only made when the model is locked.

[0048] An emergency pitch lock actuator 5 is also installed on the front frame 9 of the slider. The emergency pitch lock actuator 5 is connected to the upper caliper 12 and the lower caliper 13 through the caliper pin 14. Before the wind tunnel test begins, the model needs to be pitch locked. The emergency pitch lock actuator 5 pulls the upper caliper 12 and the lower caliper 13 to clamp the model connecting block 4 inward. When the pitch direction degree of freedom of the model is released, the emergency pitch lock actuator 5 is in a free state, that is, no force is applied to the opening and closing caliper through the caliper pin 14. When the pitch angle or pitch rate of the model exceeds the preset safety threshold, the emergency pitch lock actuator 5 is triggered within milliseconds, and the opening and closing caliper is pulled to close forcefully, so that it tightly clamps the model connecting block 4 fixed on the model, thereby forcibly restoring the model to a neutral angle of attack.

[0049] A pitch impact mitigation module is installed on the model connecting block 4. The pitch buffer spring 3 of the pitch impact mitigation module is pressed into the inside of the model connecting block 4 by the pitch buffer spring pressure plate 1 and the pitch buffer spring pressure block 2. When the opening and closing calipers are forcefully pulled closed by the pitch emergency locking actuator 5, the upper caliper 12 and the lower caliper 13 act directly on the pitch buffer spring pressure block 2 connected to the pitch buffer spring 3. Under the action of the pitch buffer spring 3, the kinetic energy of the model is converted into potential energy through the compression deformation of the spring, so that the contact force is gradually established, thereby significantly reducing the peak value of the impact load.

[0050] The buoyancy brake 24 is mounted on the right frame 18 of the slider via the active end brake beam 25. The active end brake beam 25 is mounted on the right frame 18 of the slider via brake pin 22 and brake pin fastening nut 21. The driven end brake beam 28 is mounted on the left frame 20 of the slider via brake pin 22 and brake pin fastening nut 21. The two brake pins 22 are connected by brake pin sleeve 23. The actuating end of the buoyancy brake 24 passes through the active end brake beam 25 and connects to the active end brake pad 26. The driven end brake pad 27 is mounted on the driven end brake beam 28. The active end brake pad 26 and the driven end brake pad 27 are respectively arranged on both sides of the column 29. Under the driving action of the buoyancy brake 24, the active end brake pad 26 and the driven end brake pad 27 apply huge normal pressure to the column 29 from the side, generating a strong sliding friction force, thereby urgently braking the vertical movement of the slider unit and the model. Brake pads with different friction coefficients can be used in the experiment to meet different needs. When the slider unit approaches its stroke limit, the passive buffer device will be activated simultaneously with the sinking and floating brake 24 to prevent the impact-reducing component 33 from rebounding.

[0051] Example 2, combined with Figures 1-12 This embodiment describes a heave-pitch support mechanism for dynamic testing of wind tunnel models, which includes the following states:

[0052] Free Flight State: In free flight state, the model pitches freely around the model connection axis 17. At this time, the caliper is in the open state, and the pitch limit block 6 moves to the target position under the action of the lead screw 11, thus setting the variable range of the model's pitch angle. During the test, the model connection block 4 connected to the model in the slider unit rotates around the model connection axis 17 together with the model. When the model connection block 4 touches the head of the upper caliper 12 or the lower caliper 13, it pushes the caliper to rotate. Subsequently, the caliper drives the pitch limit block guide seat 7 connected to it to rotate until the pitch limit block guide seat 7 contacts the pitch limit block 6 pre-positioned by the lead screw. The pitch limit block 6 prevents the caliper from rotating further, thereby achieving the pitch angle limit of the model. If the impact energy is extremely high or the pitch range control system fails, the model continues to move beyond the preset variable range of the model pitch angle until the upper caliper 12 or the lower caliper 13 contacts the limit platform 35 designed on the right frame 18 or the left frame 20 of the slider. At this time, the load path is completely or partially transferred from the pitch limit block 6 to the right frame 18 or the left frame 20 of the slider to prevent catastrophic damage caused by excessive rotation of the opening and closing calipers.

[0053] Safety Lockout State: When pitch range adjustment or emergency locking is required, the pitch emergency lockout actuator 5 is triggered. The pitch emergency lockout actuator 5 pulls the opening and closing caliper inward to close. The safety locking process consists of the following two steps:

[0054] Step 1: Hard contact and attitude fixation. The upper caliper 12 and lower caliper 13 tightly clamp the model connecting block 4 fixed on the model. At this time, the model is forcibly fixed at a neutral angle of attack.

[0055] Step 2: Establishing a three-point support. The caliper not only clamps the model connecting block 4 but also continues to close inward until the upper caliper 12 and lower caliper 13 contact and press against the pitch lock pin 16 on their inner sides. This forms a three-point contact consisting of four contact points on both sides of the model connecting block 4, four contact points on both sides of the pitch lock pin, and four contact points on both sides of the caliper engaging with the tail caliper pin 14. This three-point contact forms a statically determinate structure between the caliper, the model connecting block 4, and the pitch lock pin 16, eliminating all play. At this point, the pitch freedom is completely physically locked, and the model, the caliper, and the pitch lock pin 16 become a rigid whole.

[0056] In the locked state, the pitch range adjustment is performed by remotely starting the drive source 10 when the three points are fully locked. The drive source 10 rotates forward or backward, causing the lead screw 11 to rotate. The two pitch limit blocks 6 on the lead screw 11 begin to move within the pitch limit block guide seat 7, moving closer or further away from each other synchronously. After the adjustment is completed, the pitch limit blocks 6 are fixed in the new position, and the variable range of the model's pitch angle is updated.

[0057] After unlocking and entering the new flight range, once adjustments are complete, the pitch lock emergency actuator 5 is activated. Under the action of the pitch buffer spring 3 and the return of the pitch emergency lock actuator 5, the opening / closing caliper disengages from the pitch lock pin 16, releasing from the three-point contact state and remaining in the open position. At this time, the opening angle of the opening / closing caliper remains unchanged, but the effective range of the model's pitch motion has been redefined. The model can fly freely within a new, smaller, or larger angle range until it is locked again or reaches a new limit.

[0058] When the float brake 24 is locked, its output shaft drives the active brake pad 26 connected to it to apply a huge normal pressure to the column 29 from the side. After the active brake pad 26 contacts the column 29, the output shaft of the float brake 24 continues to extend and drives the driven brake beam 28 to move closer to the column 29 through the active brake beam 25 and its connected brake pin fastening nut 21 and brake pin 22 until the driven brake pad 27 connected to the driven brake beam 28 contacts the column 29. The combined normal force of the active brake pad 26 and the driven brake pad 27 on the column 29 from the side makes the slider unit achieve emergency braking in the float direction.

[0059] Example 3, combined with Figures 1-12 This embodiment describes a method for using a heave-pitch support mechanism for dynamic testing of wind tunnel models, comprising the following steps:

[0060] Step 1: Preparation and installation. Fix the column 29 to the center of the wind tunnel test section through the column diagonal brace 31. Install the slider unit on the column 29. Install the model on the slider unit through the model connecting shaft 17 and the model connecting block 4.

[0061] Step 2: Pre-test setup. With the model in pitch lock and buoyancy brake state, control the drive source 10 to drive the lead screw 11. With the rotation of the lead screw 11, control the position of the pitch limit block 6 and the pitch limit block guide seat 7, set the range of motion of the model pitch angle, and check the function of the pitch emergency lock actuator 5 and the buoyancy brake 24.

[0062] Step 3: Model release and trimming. Start the wind tunnel to reach the preset test dynamic pressure. First, release the pitch emergency lock actuator 5 and simultaneously activate the model pitch attitude controller to ensure that the model is physically locked in the vertical direction and establishes attitude stability. Then, release the buoyancy brake 24 and simultaneously activate the model vertical position controller. On the basis of controllable model attitude, give it vertical motion capability. The model takes off smoothly on the impact mitigation lever 34. The model pitch attitude controller and the model vertical position controller control the model to fly to the center position of the test section for trimming, simulating free flight.

[0063] Step 4: Dynamic testing and safety monitoring. Execute test tasks, such as gust response, flutter boundary detection, or load mitigation control law verification. Monitor the model's heave position, pitch attitude, heave speed, and pitch rate in real time. When any parameter exceeds the preset threshold, automatically trigger the safety sequence, activate the heave brake 24 to decelerate, and command the pitch emergency lock actuator 5 to control the opening and closing calipers to close inward and clamp the model connecting block, forcibly fixing the model at a neutral angle of attack.

[0064] After the opening and closing caliper clamps the model connecting block 4, it continues to move inward until the upper caliper 12 and the lower caliper 13 contact and press against the pitch lock stop pin 16 respectively. At this time, the upper caliper 12, the lower caliper 13, the model connecting block 4 and the pitch lock stop pin 16 form a statically determinate structure, eliminating all movement gaps. The pitch freedom of the model is completely physically locked, and the model, the opening and closing caliper and the pitch lock stop pin 16 become a rigid whole.

[0065] Or, if the model reaches the vertical travel limit, the passive buffer device is triggered and works together with the buoyancy brake 24 to bring the model to a safe stop with a small impact load.

[0066] Step 5: Model landing and recovery. After the test, the model is guided to the lower end to land on the passive buffer device by the position controller, or the braking and locking are directly triggered to reduce the wind tunnel dynamic pressure and allow the model to sink smoothly.

[0067] This embodiment is merely an exemplary illustration of the present invention and does not limit its scope of protection. Those skilled in the art can make partial changes to it, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A heave-pitch support mechanism for dynamic testing of wind tunnel models, characterized in that: It includes a main frame, a slider unit, and a passive buffer device. The passive buffer device is installed on the main frame, and the slider unit is slidably mounted on the main frame. The main frame includes columns (29), column connecting plates (30) and column diagonal braces (31). The upper and lower ends of the columns (29) are connected to the column diagonal braces (31) through the column connecting plates (30). The columns (29) are connected to the top plate and floor of the wind tunnel test section through the column diagonal braces (31). A set of passive buffer devices is installed at the top and bottom of the columns (29). The slider unit is arranged on the outside of the column (29). The slider unit is connected to the column (29) through a magnetic component (15). A sinking and floating brake (24) is installed on the slider unit. A pair of opening and closing calipers are symmetrically installed on the slider unit. The opening and closing calipers include an upper caliper (12) and a lower caliper (13). The upper caliper (12) and the lower caliper (13) are respectively hinged to the slider unit through caliper pins. The opening and closing calipers are connected to the pitch limit block guide seat (7) through caliper pins (14). The pitch limit block guide seat (7) is fitted on the pitch limit block (6). The pitch limit block (6) is connected to the lead screw (11). The lead screw (11) is mounted on the slider unit via the lead screw mounting base (8). The lead screw (11) is driven by the drive source (10). The slider unit is equipped with a pitch lock pin (16). The pitch lock pins (16) are arranged on the inner side of the opening and closing caliper. The pitch emergency lock actuator (5) is mounted on the slider unit. The pitch emergency lock actuator (5) is connected to the opening and closing caliper via the caliper pin (14). The model is mounted on the slider unit via the model connecting shaft (17). The model is connected to the model connecting block (4). The opening and closing caliper limits the pitch angle of the model via the model connecting block (4).

2. The heave and pitch support mechanism for dynamic testing of wind tunnel models according to claim 1, characterized in that: The passive buffer device includes a limiting bracket (32), an impact mitigation component (33), and an impact mitigation rod (34). The limiting bracket (32) is installed on the upper and lower ends of the column (29) through the column connecting plate (30). The limiting bracket (32) is equipped with the impact mitigation component (33) and the impact mitigation rod (34). One end of the impact mitigation rod (34) passes through the limiting bracket (32) and the column connecting plate (30).

3. The heave and pitch support mechanism for dynamic testing of wind tunnel models according to claim 2, characterized in that: The impact mitigation component (33) is a limit spring or a damper.

4. The heave and pitch support mechanism for dynamic testing of wind tunnel models according to claim 2, characterized in that: The slider unit includes a front slider frame (9), a right slider frame (18), a rear slider frame (19), and a left slider frame (20). The front slider frame (9), the right slider frame (18), the rear slider frame (19), and the left slider frame (20) are connected in sequence to form a frame surrounding the outside of the column (29). Magnetic components (15) are installed on the inner sides of the front slider frame (9), the right slider frame (18), the rear slider frame (19), and the left slider frame (20). Opening and closing calipers and pitch lock pins (16) are installed on the right slider frame (18) and the left slider frame (20), respectively. The model connecting block (4), the pitch emergency lock actuator (5), and the lead screw mounting seat (8) are installed on the front slider frame (9).

5. The heave and pitch support mechanism for dynamic testing of wind tunnel models according to claim 4, characterized in that: The right frame (18) of the slider is equipped with a sinking and floating brake (24). The active end brake beam (25) is installed on the right frame (18) of the slider through the brake pin (22) and the brake pin fastening nut (21). The driven end brake beam (28) is installed on the left frame (20) of the slider through the brake pin (22) and the brake pin fastening nut (21). The two brake pins (22) are connected through the brake pin sleeve (23). The actuating end of the sinking and floating brake (24) passes through the active end brake beam (25) and is connected to the active end brake pad (26). The driven end brake pad (27) is installed on the driven end brake beam (28). The active end brake pad (26) and the driven end brake pad (27) are respectively arranged on both sides of the column (29).

6. The heave and pitch support mechanism for dynamic testing of wind tunnel models according to claim 5, characterized in that: Limiting surfaces (35) are respectively machined on the right frame (18) and left frame (20) of the slider.

7. The heave and pitch support mechanism for dynamic testing of wind tunnel models according to claim 6, characterized in that: The model connecting block (4) is equipped with a pitch impact mitigation module, which includes a pitch buffer spring pressure plate (1), a pitch buffer spring pressure block (2), and a pitch buffer spring (3). The pitch buffer spring (3) is pressed into the inside of the model connecting block (4) by the pitch buffer spring pressure plate (1) and the pitch buffer spring pressure block (2). The pitch impact mitigation module is longitudinally aligned with the opening and closing caliper.

8. A method for using a heave-pitch support mechanism for dynamic testing of a wind tunnel model, the method being implemented based on the heave-pitch support mechanism for dynamic testing of a wind tunnel model as described in claim 7, characterized in that... Includes the following steps: Step 1: Preparation and installation. Fix the column (29) to the center of the wind tunnel test section through the column diagonal brace (31), install the slider unit on the column (29), and install the model on the slider unit through the model connecting shaft (17) and the model connecting block (4). Step 2: Pre-test setup. In the pitch lock and buoyancy brake states of the model, control the drive source (10) to drive the lead screw (11). Under the rotation of the lead screw (11), control the position of the pitch limit block (6) and the pitch limit block guide seat (7), set the range of motion of the model pitch angle, and check the function of the pitch emergency lock actuator (5) and the buoyancy brake (24). Step 3: Model release and balancing. Start the wind tunnel to reach the preset test dynamic pressure. First, release the pitch emergency lock actuator (5) and simultaneously activate the model pitch attitude controller to ensure that the model is physically locked in the vertical direction and establishes attitude stability. Then, release the buoyancy brake (24) and simultaneously activate the model vertical position controller. On the basis of controllable model attitude, give it vertical motion capability. The model takes off smoothly on the impact mitigation rod (34). The model pitch attitude controller and the model vertical position controller control the model to fly to the center position of the test section for balancing to simulate free flight. Step 4: Dynamic testing and safety monitoring. Execute the test task and monitor the model's sinking and floating position, pitch angle attitude, sinking and floating speed and pitch angle rate in real time. When any parameter exceeds the preset threshold, the safety sequence is automatically triggered, the sinking and floating brake (24) is activated to decelerate, and the pitch emergency lock actuator (5) is commanded to control the opening and closing caliper to close inward and clamp the model connecting block, forcibly fixing the model at a neutral angle of attack. Step 5: Model landing and recovery. After the test, the model is guided to the lower end to land on the passive buffer device by the position controller, or the braking and locking are directly triggered to reduce the wind tunnel dynamic pressure and allow the model to sink smoothly.

9. The method of using the heave-pitch support mechanism for dynamic testing of wind tunnel models according to claim 8, characterized in that: In step four, after the caliper clamps the model connecting block (4), it continues to move inward until the upper caliper (12) and the lower caliper (13) contact and press against the pitch lock stop pin (16) respectively. At this time, the upper caliper (12), the lower caliper (13), the model connecting block (4) and the pitch lock stop pin (16) form a statically determinate structure, eliminating all movement gaps. The pitch freedom of the model is completely physically locked, and the model, the caliper and the pitch lock stop pin (16) become a rigid whole.

10. The method of using the heave-pitch support mechanism for dynamic testing of wind tunnel models according to claim 8, characterized in that: In step four, when the model reaches the vertical travel limit, the passive buffer device is triggered and works together with the buoyancy brake (24) to bring the model to a safe stop with a small impact load.

Images