An experimental device and experimental method for measuring the ultimate flight ability of a flapping-wing aircraft

Abstract

The present invention discloses an experimental device and an experimental method for measuring the extreme flight ability of a flapping-wing aircraft, including an experimental table, on which a glass cover is provided. The experimental table and the glass cover cooperate to form a sealed cavity, and the sealed cavity is communicated with a vacuum adjustment system through a pipeline. A pressure sensor is arranged on the experimental table in the sealed cavity in cooperation with the vacuum adjustment system; a fixed bracket is further arranged on the experimental table in the sealed cavity, and a lift sensor is fixedly arranged on the fixed bracket. The lift sensor is arranged in cooperation with the flapping-wing aircraft. The lift sensor, the pressure sensor, and the flapping-wing aircraft are all arranged in cooperation with a central controller, and the central controller is used to display the lift, air pressure, and adjust the flapping frequency of the flapping-wing aircraft. Based on the experimental device of the present invention, a high-altitude / high-temperature / high-humidity environment is simulated, and the flapping-wing aircraft can complete the tests of the flight altitude limit and the maximum flight acceleration without actual flight, providing an experimental test basis for the design and optimization of the flapping-wing aircraft.

Description

Technical Field

[0001] The present invention belongs to the field of aircraft experiments, and specifically relates to an experimental device and an experimental method for measuring the ultimate flight ability of a flapping-wing aircraft. Background Art

[0002] Since the concept of Micro Air Vehicle (MAV) was proposed by the Defense Advanced Research Projects Agency (DARPA) of the United States, MAV has become an important research and development direction in the field of aviation. Whether in the military field, such as tasks like low-altitude reconnaissance, target navigation, electronic jamming, and ground attack, or in the civilian field, such as post-disaster target search and rescue, terrain exploration, urban monitoring, and even future Mars exploration, MAV has incomparable advantages. When the characteristic scale of MAV is reduced to less than 15 cm, the flight efficiency of traditional fixed-wing or rotary-wing aircraft drops sharply, while flapping-wing flight has unique advantages.

[0003] The research on flapping-wing aircraft belongs to the category of multidisciplinary cross-research. Experts and scholars at home and abroad generally conduct research on it by integrating aspects such as bionics, flight mechanics, CFD numerical simulation technology, and visualization of flow field testing technology. Bionics mainly studies the aerodynamic mechanism from aspects such as the wingtip movement trajectory, flapping mode, and wing shape of flying organisms. Thanks to the progress of Digital Particle Image Velocimetry (DPIV) and high-speed camera technology, in terms of experiments, the complex vortex system structure of flapping-wing flight can be revealed based on flow field visualization technology, and the influence of the vortex system on lift can be studied.

[0004] In the military field, in the actual use environment, flapping-wing aircraft will inevitably encounter various harsh natural climate conditions. For example, when flying in high-altitude areas, the flapping-wing aircraft will encounter a significant reduction in flight limits due to the thin air density, and may even make it difficult for the flapping-wing aircraft to take off; the high-humidity atmospheric environment encountered in tropical jungles will also affect the flapping efficiency of the wings; the high-temperature and high-heat environment in the desert will affect the actual performance of the flapping-wing aircraft. Based on the above diversification and complexity of the application environment of flapping-wing aircraft, it can be known that for flapping-wing aircraft, not only conventional flight test experiments but also flight test experiments under extreme climate conditions are required.

[0005] The patent situation in China regarding the test and measurement technology of flapping-wing aircraft is as follows:

[0006] For the patent "An apparatus for measuring the aerodynamic efficiency and mechanical efficiency of a flapping-wing micro-aircraft (ZL202010783096.9)", although it also uses a combination of a vacuum pump and a vacuum hood to create an approximately vacuum environment, its purpose is to compare the power difference consumed by the system in the vacuum environment and the real environment, so as to obtain mechanical power consumption, inertial power consumption, and aerodynamic power consumption;

[0007] The patent "An experimental device for testing a bird - like flapping - wing aircraft and its testing method (ZL202010769337.4)" uses the main frame of the axial positioning bracket and the inclined beam. Based on the force - measuring sensor, through the distribution of forces and algorithms, the lift force, thrust force, and pitching moment of the flapping - wing aircraft are obtained;

[0008] The patent "A measurement platform for the average lift force and wing motion synchronization of a flapping - wing micro - aircraft (ZL202010783933.8)" uses three orthogonal high - speed cameras to measure the wing motion parameters and uses a wind - shield and an electronic scale structure to test the lift force of the flapping - wing aircraft;

[0009] The patent "An aerodynamic force testing device for a flapping - wing aircraft (ZL202011312289.2)" directly tests the aerodynamic forces of the flapping - wing aircraft, that is, lift force, drag force, and rolling moment, by using the mode of pasting strain gauges on the cantilever beam;

[0010] In summary, most of the current domestic patents on the testing systems related to flapping - wing aircraft mainly focus on testing the aerodynamic forces of the flapping wings (lift force, thrust force, rolling moment), the motion parameters of the airfoil (tested with high - speed cameras), and testing its energy consumption by means of vacuum pumping. However, there are no relevant experimental testing equipment and testing methods for the flight altitude limit of flapping - wing aircraft and the influence of changing meteorological conditions (such as temperature, humidity, air density, etc.) on flight ability. Summary of the Invention

[0011] One of the purposes of the present invention is to provide an experimental device and an experimental method for measuring the extreme flight ability of a flapping - wing aircraft, so as to solve the problem in the background technology that the existing experimental testing equipment lacks the ability to test the flight altitude limit of flapping - wing aircraft in high - altitude, high - temperature, and high - humidity environments.

[0012] To achieve the above - mentioned purpose, the present invention provides the following technical solutions:

[0013] An experimental device for measuring the extreme flight ability of a flapping - wing aircraft, including an experimental table, on which a glass cover is provided. The experimental table and the glass cover cooperate to form a sealed cavity. The sealed cavity is connected to a vacuum adjustment system through a pipeline. A pressure sensor is provided on the experimental table in the sealed cavity in cooperation with the vacuum adjustment system; a fixed bracket is also provided on the experimental table in the sealed cavity, and a lift sensor is fixedly arranged on the fixed bracket. The lift sensor is arranged in cooperation with the flapping - wing aircraft. The lift sensor, the pressure sensor, and the flapping - wing aircraft are all arranged in cooperation with a central controller, and the central controller is used to display the lift force, air pressure, and adjust the flapping frequency of the flapping - wing aircraft.

[0014] Preferably, a heating sheet and a temperature sensor are also provided on the experimental table in the sealed cavity. The heating sheet and the temperature sensor are both arranged in cooperation with the central controller, and are used to adjust the temperature of the heating sheet and display the temperature.

[0015] Preferably, a humidity adjustment system is provided outside the sealed chamber. The humidity adjustment system includes a water storage tank, a water pump, and a water mist generator. The output end of the water storage tank is cooperatively arranged with the input end of the water pump. The output end of the water pump is cooperatively provided with a water pipe, and the output end of the water pipe is cooperatively arranged with the water mist generator. The output end of the water mist generator is communicated with the sealed chamber. The water mist generator is cooperatively arranged with a central controller for controlling the opening and closing of the water mist generator. A humidity sensor is provided on the experimental bench in the sealed chamber, and the humidity sensor is cooperatively arranged with the central controller for displaying the humidity.

[0016] Preferably, the vacuum adjustment system includes a pipeline communicated with the sealed chamber, and one end of the pipeline is communicated with a vacuum pump through an adjustment valve.

[0017] Preferably, a rubber sealing ring is cooperatively arranged between the glass cover and the experimental bench.

[0018] Preferably, the central controller includes a data synchronization module, a display module, and an adjustment module. The data synchronization module is used for synchronizing sensor data. The display module is used for displaying the synchronized sensor data. The adjustment module is used for adjusting the temperature and humidity in the sealed chamber and the flapping frequency.

[0019] An experimental method for measuring the ultimate flight ability of a flapping-wing aircraft includes a flight limit experiment of the flapping-wing aircraft in a high-altitude environment.

[0020] Step 1: Check the sealing performance of the sealed chamber.

[0021] Step 2: Open the adjustment valve, start the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap at the maximum flapping frequency, and obtain a stable lift force L. Calculate the maximum acceleration of the flapping-wing aircraft during takeoff on the ground based on the lift force L.

[0022] Step 3: Adjust the heating sheet through the central controller to make the temperature in the sealed chamber reach the temperature corresponding to the preset altitude. Start the vacuum pump, adjust the adjustment valve to make the air pressure in the sealed chamber reach the air pressure corresponding to the preset altitude.

[0023] Step 4: Start the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap at a fixed frequency and reach dynamic balance, and judge the relationship between the lift force L and the self-weight G of the flapping-wing aircraft. If L = G, the flight limit altitude H of the flapping-wing aircraft is the preset altitude. If L > G, change the corresponding temperature and air pressure in the sealed chamber to increase the altitude until L = G. If L < G, change the corresponding temperature and air pressure in the sealed chamber to decrease the altitude until L = G.

[0024] Step 5: Determine the relative flight height h of the flapping-wing aircraft based on the flight limit altitude H and the environmental altitude H on ​

[0025] Preferably, it also includes the flight limit experiment of the flapping-wing aircraft at a specific temperature.

[0026] Step 1: Check the sealing performance of the sealed chamber.

[0027] Step 2: Close the regulating valve, and adjust the heating element through the central controller to make the temperature in the sealed chamber reach the preset temperature.

[0028] Step 3: Adjust the air pressure in the sealed chamber to be consistent with the preset ground air pressure P h through the vacuum regulating system.

[0029] Step 4: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap stably at the maximum flapping frequency, and obtain the stable lift L. Calculate the maximum acceleration of the flapping-wing aircraft in the high-temperature environment based on the lift L.

[0030] Step 5: Keep the temperature in the sealed chamber unchanged, and reduce the air pressure in the sealed chamber until the lift is consistent with the self-weight of the flapping-wing aircraft to obtain the minimum air pressure P min , and determine the altitude H based on the minimum air pressure P min and the preset ground air pressure P h .

[0031] Step 6: Determine the relative flight height h of the flapping-wing aircraft based on the flight limit altitude H and the environmental altitude H on .

[0032] Preferably, it also includes the flight limit experiment of the flapping-wing aircraft at a specific humidity.

[0033] Step 1: Check the sealing performance of the sealed chamber.

[0034] Step 2: Close the regulating valve, turn on the power supply of the water pump, start the water mist generator through the central controller until the preset humidity is reached, and then turn off the water mist generator and the water pump.

[0035] Step 3: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap stably at the maximum flapping frequency, and obtain the stable lift L. Calculate the maximum acceleration of the flapping-wing aircraft in the high-humidity environment based on the lift L.

[0036] Step 4: Keep the humidity in the sealed chamber unchanged, and reduce the air pressure in the sealed chamber until the lift is consistent with the self-weight of the flapping-wing aircraft to obtain the minimum air pressure P min , and determine the altitude H based on the minimum air pressure P min and the ground air pressure P on .

[0037] Step 5: Based on the flight limit altitude H and the environmental altitude H on Determine the relative flight altitude h of the flapping-wing aircraft.

[0038] Preferably, the checking of the sealing property of the sealed cavity comprises:

[0039] Step 1.1: Open the regulating valve and start the vacuum pump until the air pressure in the sealing chamber is less than 50KPa, then close the regulating valve and the vacuum pump;

[0040] Step 1.2: Determine whether the change value of the air pressure in the sealing cavity within the preset time period is greater than the preset change threshold. If so, check or replace the rubber sealing ring and return to step 1.1; otherwise, the sealing is qualified.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1) Based on the experimental device of the present invention, the atmospheric environment of high altitude and high-altitude thin air is simulated, and the flapping-wing aircraft can complete the test of the flight altitude limit and the maximum flight acceleration without actual flight;

[0043] 2) Based on the experimental device of the present invention, a harsh high-temperature environment such as a desert is simulated, and the flight altitude limit and maximum flight acceleration of the flapping-wing aircraft in this environment are tested by the experimental method of the present invention;

[0044] 3) Based on the experimental device of the present invention, a high humidity environment such as a tropical jungle is simulated, and the flight altitude limit and maximum flight acceleration of a flapping-wing aircraft in the environment are tested by the experimental method of the present invention.

[0045] 4) The present invention can qualitatively and quantitatively analyze the impact of changes in meteorological conditions (such as temperature, humidity, air density, etc.) on flapping-wing aircraft, providing an experimental test basis for the design and optimization of flapping-wing aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a front view of an experimental device for measuring the ultimate flight capability of a flapping-wing aircraft.

[0047] Figure 2 The present invention is a top view of an experimental device for measuring the ultimate flight capability of a flapping-wing aircraft.

[0048] Figure 3 This is a schematic diagram of the structure of the central controller.

[0049] Figure 4 are the standard atmospheric parameters corresponding to different altitudes.

[0050] Figure 5 This is the correspondence table between absolute humidity and relative humidity. Description of the drawings:

[0052] Water pump 1, water storage tank 2, central controller 3, bottom plate 4, glass cover 5, flapping-wing aircraft 6, lift sensor 7, fixing bracket 8, rubber sealing ring 9, experimental bench 10, vacuum pump 11, regulating valve 12, pipeline 13, heating element 14, temperature and humidity sensor 15, pressure sensor 16, water mist generator 17, steel pipe joint 18, fastening screw 19, water pipe 20, display module 301, flapping-wing adjustment knob 302, temperature adjustment knob 303, humidity adjustment knob 304. Specific implementation mode

[0053] Next, the technical solution of the present invention will be further explained in combination with embodiments and drawings.

[0054] Embodiment 1:

[0055] An experimental device for measuring the ultimate flight ability of a flapping-wing aircraft, including an experimental bench, a glass cover is provided on the experimental bench, the experimental bench and the glass cover cooperate to form a sealed cavity, the sealed cavity is communicated with a vacuum adjustment system through a pipeline, and a pressure sensor is provided on the experimental bench in the sealed cavity in cooperation with the vacuum adjustment system; a fixing bracket is further provided on the experimental bench in the sealed cavity, a lift sensor is fixedly arranged on the fixing bracket, the lift sensor is arranged in cooperation with the flapping-wing aircraft, and the lift sensor, the pressure sensor, and the flapping-wing aircraft are all arranged in cooperation with a central controller, and the central controller is used to display the lift, air pressure, and adjust the flapping frequency of the flapping-wing aircraft.

[0056] Furthermore, the vacuum adjustment system includes a pipeline communicated with the sealed cavity, one end of the pipeline is communicated with a vacuum pump through a regulating valve. The bottom plate is provided with a through hole at one end of the pipeline, one end of the pipeline is fixedly arranged at the bottom of the bottom plate, the other end of the pipeline is communicated with the air inlet of the regulating valve, and the air outlet of the regulating valve is communicated with the air extraction port of the vacuum pump. The regulating valve can be a throttle valve for regulating the gas flow rate.

[0057] In the present invention, the test bench includes a test bench frame and a bottom plate, and the bottom plate is fixedly arranged on the test bench frame through fastening screws; the glass cover has a semi-circular structure, and the vacuum adjustment system evacuates the sealed cavity through a pipeline to adjust the air pressure in the sealed cavity. A pressure sensor is arranged on the bottom plate inside the glass cover, and the pressure sensor is cooperatively arranged with a central controller so that the central controller can synchronously display the air pressure in the sealed cavity detected by the pressure sensor; a fixing bracket is fixedly arranged on the bottom plate inside the sealed cavity, and the fixing bracket is used to fix a lift sensor. The lift sensor is cooperatively arranged with the flapping-wing aircraft to detect the lift of the flapping-wing aircraft. As a specific embodiment of the present invention, the lift sensor is arranged below the flapping-wing aircraft; the lift sensor and the flapping-wing aircraft are also cooperatively arranged with the central controller. The central controller can synchronously display the lift detected by the lift sensor and can adjust the flapping frequency of the flapping wings of the flapping-wing aircraft. How the central controller controls the flapping frequency of the flapping-wing aircraft is common knowledge in the art, and those skilled in the art can set it according to actual situations.

[0058] Further, a rubber sealing ring is cooperatively arranged between the glass cover and the bottom plate. Here, the sealing rubber sealing ring is used to ensure the airtightness of the sealed cavity to improve the stability of experimental data.

[0059] Based on the above experimental device for measuring the flight limit of a flapping-wing aircraft, the experimental method for the flight limit of the flapping-wing aircraft includes: under the condition of ensuring good airtightness of the sealed cavity, adjusting the vacuum degree of the sealed cavity through a vacuum pump and an adjusting valve, and testing the relationship between the lift of the flapping-wing aircraft at a preset fixed frequency and different vacuum degrees through a pressure sensor and a lift sensor, obtaining the relationship between the lift of the flapping-wing aircraft at a preset fixed frequency and different altitudes, which can be converted into a table form. When the user uses the flapping-wing aircraft to perform a flight mission, the Newton interpolation method can be used to calculate the specific flight limit height and the maximum takeoff acceleration of the aircraft at the altitude where it is located.

[0060] In the present invention, the vacuum degree corresponds to the altitude. The vacuum degree, that is, the air pressure, and the corresponding relationship with the altitude can be seen Figure 4 in the standard atmospheric parameters corresponding to different altitudes. By calculating the lift L consistent with the self-weight G of the flapping-wing aircraft through the Newton difference method, and obtaining the altitude corresponding to the lift L as the flight limit height; setting the preset fixed frequency as the maximum flapping frequency, and calculating the maximum takeoff acceleration based on the obtained stable lift L.

[0061] The experimental device in this embodiment has a simple structure and a low manufacturing cost, and the experimental method is easy to operate.

[0062] Embodiment 2:

[0063] An experimental device for measuring the ultimate flight ability of a flapping-wing aircraft. On the basis of Embodiment 1, this experimental device further includes a heating sheet and a temperature sensor. Both the heating sheet and the temperature sensor are arranged on the experimental bench in the sealed cavity, and the heating sheet and the temperature sensor are both arranged in cooperation with the central controller for adjusting the temperature of the heating sheet and displaying the temperature.

[0064] In the present invention, both the heating sheet and the temperature sensor are arranged on the bottom plate in the glass cover. There are two heating sheets, which are respectively arranged at the front and rear ends on the right side of the fixed bracket. Both heating sheets are arranged in cooperation with the central controller, and the central controller can control the heating temperature of the heating sheet; the temperature sensor is arranged on the front side of the fixed bracket, and the temperature sensor is also arranged in cooperation with the central controller so that the central controller can synchronously display the air temperature in the sealed cavity detected by the temperature sensor.

[0065] The experimental method using this experimental device for measuring the ultimate flight ability of a flapping-wing aircraft includes the flight limit experiment of the flapping-wing aircraft in a high-altitude environment, which specifically includes 5 steps:

[0066] Step 1: Check the airtightness of the sealed cavity, including the following 2 sub-steps:

[0067] Step 1.1: Open the regulating valve and turn on the vacuum pump. When the air pressure in the sealed cavity is less than 50 KPa, close the regulating valve and the vacuum pump;

[0068] Step 1.2: Judge whether the change value of the air pressure in the sealed cavity within the preset time period is greater than the preset change threshold. If so, check or replace the rubber sealing ring and return to Step 1.1. Otherwise, the airtightness is qualified.

[0069] Here, the preset time period is 3 min, the preset change threshold can be 1 KPa or greater, and the change value here is the absolute value.

[0070] Step 2: Open the regulating valve, turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap at the maximum flapping frequency, and obtain the stable lift L. Calculate the maximum acceleration of the flapping-wing aircraft during takeoff on the ground based on the lift L

[0071] where g is the acceleration due to gravity, and the lift L is the stable lift in this step.

[0072] Step 3: Adjust the heating sheet through the central controller to make the air temperature in the sealed cavity reach the air temperature corresponding to the preset altitude. Turn on the vacuum pump and adjust the regulating valve to make the air pressure in the sealed cavity reach the air pressure corresponding to the preset altitude.

[0073] Here, the altitude refers to the height relative to the sea level, and it is stipulated that the meteorological conditions at the sea level are the international standard meteorological conditions, specifically as follows:

[0074] The air is dry air;

[0075] The air temperature T on = 15 °C;

[0076] The pressure P on = 101325 Pa;

[0077] The air density ρ on = 1.225 kg / m³.

[0078] In the present invention, when the preset altitude H = 1000 m, according to Figure 4 the corresponding temperature 282.572 K and the corresponding air pressure 0.887300168 P are determined on , the heating sheet is adjusted through the central controller so that the central controller displays the air temperature at the current preset altitude as 282.572 K, the vacuum pump is turned on for air extraction, and the regulating valve is slowly adjusted so that the central controller displays the air pressure at the current preset altitude as 0.887300168 P on , P on is the sea-level air pressure.

[0079] Step 4: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap at a fixed frequency, and achieve dynamic balance. Judge the relationship between the lift force L and the self-weight G of the flapping-wing aircraft. If L = G, the flight limit altitude H of the flapping-wing aircraft is the preset altitude; if L > G, change the corresponding sealed cavity temperature and air pressure to increase the altitude until L = G. If L < G, change the corresponding sealed cavity temperature and air pressure to decrease the altitude until L = G.

[0080] In the present invention, if the frequency is not fixed, the lift force will also change accordingly. By setting a fixed frequency, the stability of the lift force is ensured to achieve dynamic balance, so that the lift force is equal to the gravity.

[0081] In the present invention, if L = G, the flight limit altitude of the flapping-wing aircraft is 1000 m; if L > G, the flight limit altitude of the flapping-wing aircraft is greater than 1000 m. At this time, a height interval (200 m) should be increased, that is, continue to evacuate, and adjust the heating sheet temperature to the corresponding value through the central controller until the two are equal, and find the corresponding flight limit altitude H; if L < G, the flight limit altitude of the flapping-wing aircraft is less than 1000 m. At this time, a height interval (200 m) should be decreased, that is, open the regulating valve to appropriately reduce the vacuum degree, and adjust the heating sheet temperature to the corresponding value through the central controller, and then continue the experiment, test the lift force L of the flapping-wing aircraft, and make it equal to the self-weight G of the flapping-wing aircraft to obtain the corresponding flight limit altitude H.

[0082] In the present invention, since the air pressure and temperature at different altitudes are different, when it is necessary to increase the altitude, the air pressure and temperature need to be adjusted. However, it should be noted that the corresponding values here are not Figure 4 the values corresponding to specific altitudes in Figure 4 , but the change values. For example, when the ground altitude is 0 and the temperature is 30 degrees, through Figure 4 it is known that when rising 1000 m, the temperature drops by 6 degrees, then the experimental temperature is adjusted to 24 degrees. If the temperature corresponding to the ground altitude of 0 is 20 degrees and the altitude rises by 1000 m, the temperature is adjusted to 14 degrees.

[0083] Step 5: Based on the flight limit altitude H and the environmental altitude H on Determine the relative flight altitude h of the flapping-wing aircraft.

[0084] In the present invention, since the flight limit altitude refers to the altitude relative to sea level, therefore, the relative flight altitude h of the flapping-wing aircraft is the difference between the flight limit altitude H and the environmental altitude H on , denoted as h = H - H on , and the environmental altitude H on is the altitude of the take-off position point of the flapping-wing aircraft. This parameter is obtained by actually measuring the local atmospheric parameters and looking up Figure 4 .

[0085] During the actual flapping-wing flight, in most cases, what is concerned is not H and H on , but the relative flight altitude h of the flapping-wing aircraft. Therefore, the measurement of the relative flight altitude of the flapping-wing aircraft becomes an important test parameter of the present invention.

[0086] The experimental method applying the experimental device for measuring the limit flight ability of the flapping-wing aircraft further includes the flight limit experiment of the flapping-wing aircraft under a specific humidity, which specifically includes 5 steps:

[0087] Step 1: Check the sealing performance of the sealing cavity. The method for checking the sealing performance of the sealing cavity in Step 1 here is the same as that in the above-mentioned Step 1.

[0088] Step 2: Close the regulating valve, and adjust the heating sheet through the central controller to make the air temperature in the sealing cavity reach the preset temperature.

[0089] In the present invention, the heating sheet is adjusted through the central controller until the central controller displays that the air temperature detected by the temperature sensor is the preset temperature, and a high-temperature air environment is simulated through Step 2.

[0090] Step 3: Adjust the air pressure in the sealing cavity to be consistent with the preset ground air pressure P h through the vacuum regulating system.

[0091] Under normal circumstances, when the sealed chamber is heated, the internal pressure will increase accordingly. At this time, the regulating valve should be slowly opened, and the air in the glass cover will be slowly released under the action of the high-pressure environment. Observe the pressure parameter on the central controller to determine whether the preset ground pressure is reached. If the internal pressure of the glass cover is still too high after the regulating valve is fully opened, then turn on the vacuum pump for negative pressure pumping. At this time, it should be noted that the regulating valve cannot be fully opened, only fine-tuned, and the internal pressure of the vacuum cover is adjusted to the required range; if the air pressure adjustment exceeds the amount, first close the regulating valve and then turn off the vacuum pump, and make the external air supplement into the sealed chamber by fine-tuning the regulating valve to adjust the internal pressure to the required range.

[0092] In step 3 of this embodiment, the preset bottom air pressure P h is the standard atmospheric pressure P on , simulating the high-temperature environment under the standard atmospheric pressure.

[0093] Step 4: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap stably at the maximum flapping frequency, and obtain the stable lift force L. Calculate the maximum acceleration of the flapping-wing aircraft in the high-temperature environment based on the lift force L

[0094] where g is the acceleration due to gravity, and the lift force L is the stable lift force in this step; by simulating the high-temperature environment under the standard atmospheric pressure, the maximum acceleration of the flapping-wing aircraft in this environment is obtained, so as to prevent the different atmospheric pressures from becoming factors affecting the flight of the flapping-wing aircraft.

[0095] Step 5: Keep the temperature in the sealed chamber unchanged, and reduce the air pressure in the sealed chamber until the lift force is equal to the self-weight of the flapping-wing aircraft, and obtain the minimum air pressure P min , based on the minimum air pressure P min and the preset ground air pressure P h to determine the altitude H.

[0096] In the present invention, reducing the air pressure in the sealed chamber is the same as the operation of reducing the air pressure in the sealed chamber in step 3 of this experimental method; in step 5 of the present invention, based on to obtain the corresponding pressure ratio, so as to obtain the corresponding flight limit altitude H.

[0097] Since the preset ground air pressure P h in step 3 of this embodiment is the standard atmospheric pressure P on , therefore, it can be obtained that Based on this, the corresponding pressure ratio can be obtained. Referring to Figure 4 the corresponding flight limit altitude can be obtained.

[0098] Step 6: Based on the flight limit altitude H and the environmental altitude H on to determine the relative flight height h of the flapping-wing aircraft.

[0099] Ambient altitude H on It is the altitude of the take-off position point of the flapping-wing aircraft. Here, the altitude of the take-off position point of the flapping-wing aircraft is the altitude corresponding to the preset ground air pressure.

[0100] Embodiment 3:

[0101] An experimental device for measuring the extreme flight ability of a flapping-wing aircraft. On the basis of Embodiment 2, a humidity adjustment system is provided outside the sealed cavity. The humidity adjustment system includes a water storage tank, a water pump and a water mist generator. The output end of the water storage tank is cooperatively arranged with the input end of the water pump. The output end of the water pump is cooperatively provided with a water pipe. The output end of the water pipe is cooperatively arranged with the water mist generator. The output end of the water mist generator is communicated with the sealed cavity; the water mist generator is cooperatively arranged with the central controller for controlling the opening and closing of the water mist generator; a humidity sensor is provided on the experimental table in the sealed cavity, and the humidity sensor is cooperatively arranged with the central controller for displaying the humidity.

[0102] In the present invention, the water pump is fixedly arranged on the experimental bench, the water mist generator is fixedly arranged at the bottom of the bottom plate, a through hole is provided at the bottom of the bottom plate for cooperating with the output end of the water mist generator, and the temperature sensor and the humidity sensor are integrated to form a temperature and humidity sensor.

[0103] In the present invention, considering that the actual air is not dry and the actual situation that the air contains water vapor needs to be considered. Therefore, the concept of virtual temperature τ is introduced and used to replace the temperature T. The calculation formula of the virtual temperature is where T is the temperature, unit K; P is the atmospheric pressure, unit Pa; a is the pressure of the water vapor contained in the air, unit Pa; then the gas state equation of the moist air can be rewritten as P = ρRτ, where R is the air constant, and its value is determined by the air constant. Since the air composition remains basically unchanged below 95 km above sea level, it can be considered that R is a constant, R = 287 J / (kg·K).

[0104] It should be noted that some humidity sensors detect the relative humidity. At this time, it should be converted to the absolute humidity. According to the displayed relative humidity and based on Figure 5 the mass ρ of the water vapor contained per square meter is obtained t , and the air pressure in the sealed cavity is obtained based on the gas state equation of the moist air. The gas state equation of the moist air is P t = ρ t R t T, where ρ t is the density of the water vapor, R t is the gas parameter of the water vapor, and T is the temperature.

[0105] The experimental method using the experimental device of this embodiment includes the flight limit experiment of the flapping-wing aircraft under specific humidity, which specifically includes 5 sub-steps.

[0106] Step 1: Check the airtightness of the sealed chamber. The method for checking the airtightness of the sealed chamber in Step 1 here is the same as that in Step 1 of Embodiment 2.

[0107] Step 2: Close the regulating valve, turn on the power supply of the water pump, start the water mist generator through the central controller until the preset humidity is reached, and then turn off the water mist generator and the water pump.

[0108] In Step 2 of the present invention, it is necessary to check whether the water in the water storage tank is sufficient before starting the water mist generator. If it is insufficient, add water to the scale position; the simulation of the high-humidity air environment is completed through Step 2.

[0109] Step 3: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap stably at the maximum flapping frequency, and obtain the stable lift force L. Calculate the maximum acceleration of the flapping-wing aircraft in the high-humidity environment based on the lift force L

[0110] where g is the acceleration due to gravity, and the lift force L is the stable lift force in this step.

[0111] Step 4: Keep the humidity in the sealed chamber unchanged, and reduce the air pressure in the sealed chamber until the lift force is equal to the self-weight of the flapping-wing aircraft to obtain the minimum air pressure P min , based on the minimum air pressure P min and the ground air pressure to determine the altitude H.

[0112] The ground air pressure here is the standard atmospheric pressure P on , so it can be obtained Based on this, the corresponding pressure ratio can be obtained. Referring to Figure 4 the corresponding flight limit altitude can be obtained.

[0113] Step 5: Determine the relative flight height h of the flapping-wing aircraft based on the flight limit altitude H and the environmental altitude H on

[0114] Embodiment 4: In order to ensure the dryness and cleanliness of the intake air, a set of intake air device is specially added. The intake air device includes an air compressor and a water removal and purification chamber. A desiccant is provided in the water removal and purification chamber to dry the air conveyed by the air compressor and convey the dried air into the sealed chamber.

[0115] ​The present invention can simulate experimental conditions with a pressure higher than the ambient pressure. For the Earth's atmospheric pressure environment, this is unstable and cannot guarantee that the environment where the flapping-wing aircraft is located must be lower than the standard atmospheric pressure. Therefore, it also has certain significance to study the flight performance of the flapping-wing aircraft in a higher-pressure environment.

[0116] In the present invention, the central controller includes a data synchronization module, a display module, and an adjustment module. The data synchronization module is used to synchronize sensor data, the display module is used to display the synchronized sensor data, and the adjustment module is used to adjust the temperature and humidity of the sealed chamber and the flapping frequency. Specifically, the adjustment module includes a temperature adjustment unit, a humidity adjustment unit, and a flapping frequency adjustment unit. The temperature adjustment unit is provided with a temperature adjustment knob, the humidity adjustment unit is provided with a humidity adjustment knob, and the flapping frequency adjustment unit is provided with a flapping adjustment knob. The display module includes a display screen.

[0117] Finally, it should be noted that the above is the preferred embodiment of the present invention. It should be pointed out that although the preferred embodiments of the present invention have been described, for those of ordinary skill in the art, once the basic creative concept of the present invention is known, several improvements and refinements can be made without departing from the principle of the present invention. These improvements and refinements should also be regarded as the protection scope of the present invention. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. An experimental device for measuring the ultimate flight ability of a flapping-wing aircraft, characterized in that, It includes an experimental bench with a glass cover on it. The experimental bench and the glass cover cooperate to form a sealed cavity. The sealed cavity is connected to a vacuum regulation system through a pipeline. A pressure sensor is arranged on the experimental bench in the sealed cavity in cooperation with the vacuum pumping regulation system; A fixed bracket is also arranged on the experimental bench in the sealed cavity. A lift sensor is fixedly arranged on the fixed bracket. The lift sensor is arranged in cooperation with the flapping-wing aircraft. The lift sensor, the pressure sensor, and the flapping-wing aircraft are all arranged in cooperation with a central controller. The central controller is used to display the lift, air pressure, and adjust the flapping frequency of the flapping-wing aircraft; A humidity regulation system is arranged outside the sealed cavity. The humidity regulation system includes a water storage tank, a water pump, and a water mist generator. The output end of the water storage tank is arranged in cooperation with the input end of the water pump. The output end of the water pump is provided with a water pipe in cooperation. The output end of the water pipe is arranged in cooperation with the water mist generator. The output end of the water mist generator is connected to the sealed cavity; The water mist generator is arranged in cooperation with the central controller and is used to control the opening and closing of the water mist generator; A humidity sensor is arranged on the experimental bench in the sealed cavity. The humidity sensor is arranged in cooperation with the central controller and is used to display the humidity. The vacuum regulation system includes a pipeline connected to the sealed cavity. One end of the pipeline is connected to a vacuum pump through a regulating valve.

2. The experimental device for measuring the ultimate flight ability of a flapping-wing aircraft according to claim 1, wherein A heating sheet and a temperature sensor are also arranged on the experimental bench in the sealed cavity. The heating sheet and the temperature sensor are both arranged in cooperation with the central controller and are used to adjust the temperature of the heating sheet and display the temperature.

3. An experimental device for measuring the ultimate flight ability of a flapping-wing aircraft according to claim 1, characterized in that, A rubber sealing ring is arranged in cooperation between the glass cover and the experimental bench.

4. An experimental device for measuring the ultimate flight ability of a flapping-wing aircraft according to claim 1, characterized in that, The central controller includes a data synchronization module, a display module, and an adjustment module. The data synchronization module is used to synchronize the sensor data. The display module is used to display the synchronized sensor data. The adjustment module is used to adjust the temperature and humidity of the sealed cavity and the flapping frequency.

5. An experimental method for measuring the ultimate flight ability of a flapping-wing aircraft, characterized in that, It includes the flight limit experiment of the flapping-wing aircraft in a high-altitude environment, Step 1: Check the sealing performance of the sealed cavity; Step 2: Open the regulating valve, start the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap at the maximum flapping frequency, and obtain the stable lift L. Calculate the maximum acceleration of the flapping-wing aircraft during takeoff from the ground based on the lift L ; Step 3: Adjust the heating sheet through the central controller to make the air temperature in the sealed cavity reach the air temperature corresponding to the preset altitude. Turn on the vacuum pump and adjust the regulating valve to make the air pressure in the sealed cavity reach the air pressure corresponding to the preset altitude; Step 4: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap at a fixed frequency, and reach dynamic balance. Judge the relationship between the lift L and the self-weight G of the flapping-wing aircraft. If L = G, the flight limit altitude H of the flapping-wing aircraft is the preset altitude; If L > G, change the corresponding temperature and air pressure in the sealed cavity to increase the altitude until L = G. If L < G, change the corresponding temperature and air pressure in the sealed cavity to decrease the altitude until L = G; Step 5: Determine the relative flight height h of the flapping-wing aircraft based on the flight limit altitude H and the environmental altitude Hon.

6. The experimental method for measuring the ultimate flight ability of a flapping-wing aircraft according to claim 5, characterized in that, It also includes the flight limit experiment of the flapping-wing aircraft at a specific air temperature, Step 1: Check the sealing performance of the sealed cavity; Step 2: Close the regulating valve and adjust the heating sheet through the central controller to make the air temperature in the sealed cavity reach the preset temperature; Step 3: Adjust the air pressure in the sealing cavity to be consistent with the preset ground air pressure through the vacuum adjustment system ; Step 4: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap stably at the maximum flapping frequency, and obtain the stable lift L. Calculate the maximum acceleration of the flapping-wing aircraft in a high-temperature environment based on the lift L ; Step 5: Without changing the temperature in the sealed cavity, reduce the air pressure in the sealed cavity until the lift force is equal to the weight of the flapping-wing aircraft, and obtain the minimum air pressure. , based on the minimum air pressure and the preset ground air pressure determine the altitude H; Step 6: Determine the relative flight height h of the flapping-wing aircraft based on the flight limit altitude H and the environmental altitude Hon.

7. An experimental method for measuring the ultimate flight ability of a flapping-wing aircraft according to claim 5, characterized in that It also includes the flight limit experiment of the flapping-wing aircraft at a specific humidity, Step 1: Check the sealing performance of the sealed cavity; Step 2: Close the regulating valve, turn on the power supply of the water pump, and start the water mist generator through the central controller until the preset humidity is reached, then turn off the water mist generator and the water pump; Step 3: Turn on the flapping-wing aircraft through the central controller, adjust the flapping-wing aircraft to flap stably at the maximum flapping frequency, and obtain the stable lift L. Calculate the maximum acceleration of the flapping-wing aircraft in a high-humidity environment based on the lift L ; Step 4: Without changing the humidity in the sealed cavity, reduce the air pressure in the sealed cavity until the lift force is equal to the weight of the flapping-wing aircraft, and obtain the minimum air pressure. , based on the minimum air pressure and the ground air pressure determine the altitude H; Step 5: Determine the relative flight height h of the flapping-wing aircraft based on the flight limit altitude H and the environmental altitude Hon.

8. An experimental method for measuring the extreme flight ability of a flapping-wing aircraft according to any one of claims 5-7, characterized in that, The inspection of the sealing performance of the sealing cavity includes Step 1.1: Open the regulating valve and turn on the vacuum pump. When the air pressure in the sealing cavity is less than 50 KPa, close the regulating valve and the vacuum pump; Step 1.2: Judge whether the change value of the air pressure in the sealing cavity within the preset time period is greater than the preset change threshold. If so, check or replace the rubber sealing ring and return to Step 1.

1. Otherwise, the sealing performance is qualified.

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