Unmanned helicopter snow blindness test method based on outdoor cold environment

Abstract

The invention provides an unmanned helicopter snow blindness test method based on an outdoor cold environment, and belongs to the field of helicopter flight tests. The invention aims to solve the problem of blank of related research in the technical fields of helicopter snow field flight and snow blindness in China. The method comprises the following steps: S1, selecting a test environment and a test site meeting test conditions; s2, determining flight working conditions of test safety; s3, test flight drilling; s4, after the flight path of the unmanned helicopter is determined in the test site, equipment used for the test is installed; s5, checking before the unmanned helicopter flies; s6, measuring physical characteristics of accumulated snow on the test site; s7, carrying out a test according to the determined flight condition; s8, ending the test; s9, measuring parameters after finishing; s10, arranging measuring equipment after the test; and S11, analyzing the recorded data. According to the invention, the influence characteristics of the helicopter in snowfield flight and snowblindness can be deeply researched, and the blank of related research in the technical field of helicopter snowfield flight and snowblindness in China is filled.

Description

Technical Field

[0001] The invention relates to flight test technology, in particular to a snow blindness test method for an unmanned helicopter based on an outdoor cold environment, and belongs to the field of helicopter flight tests. Background Art

[0002] With the continuous development of the aviation industry, helicopters have been widely used in many special scenarios due to their unique flight performance, including polar regions and other snow-covered areas. When helicopters take off, land, hover, and fly close to the ground in polar regions or other snow-covered scenes, the rotors interfere with the ground to form a complex unsteady flow field. Under the action of this complex flow field, the downwash airflow generated by the rotor will quickly roll up the snow particles on the ground from near the rotor, causing helicopter snow blindness. Once snow blindness occurs, the most direct consequence is a significant reduction in visibility outside the cockpit, and the pilot's line of sight is severely blocked, making it impossible to accurately see the ground space position, greatly affecting the safety and accuracy of the flight.

[0003] At the same time, helicopter engine air intake system components also face the problem of snow accumulation in snowy environments. When the snow accumulates to a certain extent, it will inevitably have a negative impact on the engine's air intake function, thereby destroying the normal operation of the engine and posing a serious threat to helicopter flight safety.

[0004] In view of the significant impact of the above-mentioned helicopter snow-covered flight and snow blindness phenomenon on flight safety, in-depth research on its impact characteristics is of great significance that cannot be ignored. Summary of the invention

[0005] A brief overview of the present invention is provided below in order to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In view of this, in order to solve the problem of the current domestic research gap in the field of helicopter snow flight and snow blindness technology, the present invention provides an unmanned helicopter snow blindness test method based on an outdoor cold environment.

[0007] The technical solution of the present invention is a snow blindness test method for an unmanned helicopter based on an outdoor cold environment, which specifically comprises the following steps:

[0008] S1. Select a test environment and test site that meets the test conditions;

[0009] S2. Determine the safe flight conditions for the test based on the performance of the unmanned helicopter and the limitations of the test environment and test site;

[0010] S3. The unmanned helicopter operator needs to conduct a test flight drill on a snow-free ground according to the determined flight conditions; and determine whether the existing snow on the test site meets the test requirements of being blown up by the rotor downwash to form a snow blindness scenario. If the snow state meets the test requirements, proceed directly to step S4; if the existing natural snow does not meet the test requirements, measures need to be taken to make the snow on the ground meet the test requirements;

[0011] S4. After determining the flight path of the unmanned helicopter at the test site, install the equipment used for the test;

[0012] S5. Conduct pre-flight inspection of unmanned helicopters;

[0013] S6. Measure the physical properties of snow at the test site;

[0014] S7. Conduct tests according to the determined flight conditions;

[0015] S8. After the single vehicle test is completed, ensure that the unmanned helicopter stops power output and check the status of the unmanned helicopter;

[0016] S9. Measure the snow parameters at the test site again and record the impact of the unmanned helicopter flight on the snow changes;

[0017] S10. Confirm whether there are any remaining tests on the day; if there are any remaining tests on the day, proceed to S5; if the full-day test is over, all the measuring equipment used in the test will be put away and stored indoors, and the unmanned helicopter will be treated for corrosion;

[0018] S11. Analyze the recorded data and evaluate the impact of meteorological environment, ground snow parameters, unmanned helicopter takeoff weight and flight conditions on the severity of snow blindness.

[0019] Furthermore, the flight conditions described in S2 include the take-off weight, flight trajectory, flight altitude, horizontal speed, vertical speed, flight and hovering time of the unmanned helicopter.

[0020] Furthermore, when the existing natural snow in the test site described in S3 cannot meet the requirements of the snow blindness test, the specific measures to be taken are as follows:

[0021] Physical method to loosen the snow layer: use mechanical equipment to directly act on the snow layer to loosen the snow layer by physical means; or, artificial snowmaking: use a snowmaking machine to artificially make snow, and then use a snowplow or snow shovel equipment to evenly distribute the snow generated by the snowmaking machine on the test site, thereby forming the loose snow conditions required for the test.

[0022] Furthermore, the equipment used in the test in S4 includes a pan-tilt camera, a mobile weather station, an anemometer, and a camera; the pan-tilt camera is installed on the front of the fuselage of the unmanned helicopter; the mobile weather station is located in a safe position in the test site;

[0023] When conducting vertical take-off and landing and hovering tests of unmanned helicopters, the ground projection of the center of the main rotor hub of the unmanned helicopter is used as the reference circle center, and the anemometer is arranged at a position within the range of two times the rotor radius. The camera is set up on the ground of the test site so that the horizontal distance of the camera's imaging field is not less than six times the rotor radius;

[0024] When conducting forward flight tests, the ground projection of the center of the main rotor hub of the unmanned helicopter on the flight trajectory of the unmanned helicopter is used as the ground reference trajectory line. Anemometers are arranged at positions selected within the range of twice the rotor radius on both sides of the ground reference trajectory line. The position of the ground camera in the test site is determined according to the ground reference trajectory line, and the horizontal distance of the camera imaging field of view is not less than six times the rotor radius.

[0025] Furthermore, the method for measuring the physical properties of snow on the test site in S6 specifically includes:

[0026] Snow temperature measurement method: Use a probe-type temperature sensor to insert into the snow test area to obtain snow temperature data at different depths;

[0027] Snow depth and density measurement method: Use a transparent snow density sampling measuring device to insert vertically downward from the top into the snow test area until it touches the ground. At this time, the measuring device has completed snow sampling. Seal the bottom of the measuring device with a cover plate, remove the snow, read the snow depth through the scale line on the transparent measuring device, and measure the weight of the snow in the container at the same time to get the overall density of the snow.

[0028] Snow particle shape and particle size measurement method: Use an electron microscope with a scale to measure the shape and particle size of snow particles in the snow test area. The specific steps are: place the electron microscope outdoors to keep the snow particles in their original shape, turn on the power of the equipment, turn on the CCD camera and display screen, use the snow sample collection board to sample the snow particles to be measured and place them in the electron microscope observation area, adjust the LED source brightness, adjust the lens position so that the snow crystal image in the image on the display screen is clear, collect and measure multiple sets of image information, and analyze the snow particle shape and particle size data.

[0029] Furthermore, the unmanned helicopter needs to be equipped with a ground station and flight data collection, transmission and recording functions to achieve real-time monitoring of the flight status.

[0030] Furthermore, the unmanned helicopter needs to be able to transmit the main rotor speed, collective pitch, and the position, altitude, heading, horizontal speed, and vertical speed of the unmanned helicopter through a flight data recording system, wherein the position information of the unmanned helicopter is provided by a GPS positioning system.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention can conduct in-depth research on the characteristics of helicopter flying in snowy areas and the influence of snow blindness, filling the gap in the relevant research in the field of helicopter flying in snowy areas and snow blindness technology in China;

[0033] 2. The present invention can simulate the real helicopter snow blindness phenomenon by conducting actual flight tests in snow-covered areas, allowing researchers to intuitively observe the actual situation when snow blindness occurs, which is more in line with the problems faced in actual flight and provides a reliable practical basis for in-depth research on the snow blindness phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0035] Figure 1 This is a flow chart of a snow blindness test method for an unmanned helicopter based on an outdoor cold environment;

[0036] Figure 2 Schematic diagram of an unmanned helicopter equipped with a gimbal camera;

[0037] Figure 3 Aerial view of the layout of the unmanned helicopter and measurement equipment at the test site.

[0038] In the figure: 1- unmanned helicopter, 2- PTZ camera, 3- mobile weather station, 4- anemometer, 5- camera. DETAILED DESCRIPTION

[0039] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0040] Example 1, reference Figure 1-3 The present embodiment is described as a snow blindness test method for an unmanned helicopter based on an outdoor cold environment, specifically comprising the following steps:

[0041] S1. Select a test environment and test site that meets the test conditions:

[0042] Choose a cold outdoor natural environment as the test environment, choose a flat area away from people as the test site, and avoid large ups and downs or obstacles; according to the size and flight characteristics of the unmanned helicopter 1, the test site needs to have enough space;

[0043] S2. Determine the flight conditions for test safety based on the performance of the unmanned helicopter 1 and the limitations of the test environment and test site:

[0044] S3. The operator of the unmanned helicopter 1 shall conduct a test flight drill on a snow-free ground according to the determined flight conditions; and determine whether the existing snow on the test site meets the test requirements of being blown up by the rotor downwash to form a snow blindness scenario. If the snow state meets the test requirements, proceed directly to step S4; if the existing natural snow does not meet the test requirements, measures shall be taken to make the snow on the ground meet the test requirements;

[0045] S4. After determining the flight trajectory of the unmanned helicopter 1 at the test site, install the equipment used for the test;

[0046] S5. Perform pre-flight inspection of the unmanned helicopter 1:

[0047] Before the test flight, ground maintenance personnel need to conduct a pre-flight inspection of the unmanned helicopter 1 to check whether the mechanical and electronic components of the unmanned helicopter 1 are normal, including the battery status, power system, and sensors; ensure that the communication connection between the unmanned helicopter 1 and the ground station is normal, and ensure that the control and data transmission are correct;

[0048] S6. Measure the physical properties of snow at the test site;

[0049] S7. Conduct tests according to the determined flight conditions:

[0050] During the vertical take-off and vertical landing tests, the unmanned helicopter 1 should maintain a smooth and slow ascending and descending process; during the hovering tests at different heights, the unmanned helicopter 1 should try to maintain a fixed position and attitude; during the forward flight test, the unmanned helicopter 1 should fly horizontally close to the ground along the set trajectory;

[0051] While conducting vertical take-off and landing, hovering and forward flight tests, collect and record the flight data of the unmanned helicopter 1, the data of the gimbal camera 2, the meteorological data of the mobile weather station 3, the data of the rotor downwash airflow anemometer 4 and the data of the ground camera 5;

[0052] S8. After the single vehicle test is completed, ensure that the unmanned helicopter 1 stops power output, check the status of the unmanned helicopter 1, and clear the snow on the aircraft in time to prevent snow particles from freezing on important components;

[0053] S9. Measure the snow parameters at the test site again and record the impact of the flight of the unmanned helicopter 1 on the change of snow;

[0054] S10. Confirm whether there are any remaining tests on the day; if there are any remaining tests on the day, proceed to S5; if the full-day test is over, all the measuring equipment used in the test will be put away and stored indoors, and the unmanned helicopter 1 will be treated with anti-corrosion to prevent wet snow and frost from causing rust or corrosion on the surface;

[0055] S11. Analyze the recorded data and evaluate the impact of meteorological environment, ground snow parameters, takeoff weight of unmanned helicopter 1 and flight conditions on the severity of snow blindness.

[0056] Furthermore, the flight conditions described in S2 include the take-off weight, flight trajectory, flight altitude, horizontal speed, vertical speed, flight and hovering time of the unmanned helicopter 1.

[0057] Furthermore, when the existing natural snow in the test site described in S3 cannot meet the requirements of the snow blindness test, the specific measures to be taken are as follows:

[0058] Physical method to loosen the snow layer: use mechanical equipment to directly act on the snow layer to loosen the snow layer by physical means; or, artificial snowmaking: use a snowmaking machine to artificially make snow, and then use a snowplow or snow shovel equipment to evenly distribute the snow generated by the snowmaking machine on the test site, thereby forming the loose snow conditions required for the test.

[0059] Furthermore, the equipment used in the test in S4 includes a pan-tilt camera 2, a mobile weather station 3, an anemometer 4, and a camera 5; the pan-tilt camera 2 is installed on the front of the fuselage of the unmanned helicopter 1; the mobile weather station 3 is located in a safe position in the test site;

[0060] When conducting the vertical take-off and landing and hovering test of the unmanned helicopter 1, the ground projection of the center of the main rotor hub of the unmanned helicopter 1 is used as the reference circle center, and the anemometer 4 is arranged at a position within the range of two times the rotor radius. The camera 5 is set up on the ground of the test site so that the horizontal distance of the imaging field of the camera 5 is not less than six times the rotor radius;

[0061] When conducting the forward flight test, the ground projection of the center of the main rotor hub of the unmanned helicopter 1 on the flight trajectory of the unmanned helicopter 1 is used as the ground reference trajectory line. Positions are selected within the range of twice the rotor radius on both sides of the ground reference trajectory line to arrange the anemometer 4. The installation position of the ground camera 5 in the test site is determined according to the ground reference trajectory line, and the horizontal distance of the imaging field of the camera 5 is not less than six times the rotor radius.

[0062] Furthermore, the method for measuring the physical properties of snow on the test site in S6 specifically includes:

[0063] Snow temperature measurement method: Use a probe-type temperature sensor to insert into the snow test area to obtain snow temperature data at different depths;

[0064] Snow depth and density measurement method: Use a transparent snow density sampling measuring device to insert vertically downward from the top into the snow test area until it touches the ground. At this time, the measuring device has completed snow sampling. Seal the bottom of the measuring device with a cover plate, remove the snow, read the snow depth through the scale line on the transparent measuring device, and measure the weight of the snow in the container at the same time to get the overall density of the snow.

[0065] Snow particle shape and particle size measurement method: Use an electron microscope with a scale to measure the shape and particle size of snow particles in the snow test area. The specific steps are: place the electron microscope outdoors to keep the snow particles in their original shape, turn on the power of the equipment, turn on the CCD camera and display screen, use the snow sample collection board to sample the snow particles to be measured and place them in the electron microscope observation area, adjust the LED source brightness, adjust the lens position so that the snow crystal image in the image on the display screen is clear, collect and measure multiple sets of image information, and analyze the snow particle shape and particle size data.

[0066] Furthermore, the unmanned helicopter 1 needs to be equipped with a ground station and flight data collection, transmission and recording functions to achieve real-time monitoring of the flight status.

[0067] Furthermore, the unmanned helicopter 1 needs to be able to transmit the main rotor speed, collective pitch, and the position, altitude, heading, horizontal speed, and vertical speed of the unmanned helicopter 1 through a flight data recording system, wherein the position information of the unmanned helicopter 1 is provided by a GPS positioning system.

[0068] Through the present invention, the influence characteristics of helicopter flying in snowy areas and snow blindness can be studied in depth, filling the gap in the relevant research fields of helicopter flying in snowy areas and snow blindness technology in China;

[0069] Through the present invention, by conducting actual flight tests in snow-covered areas, real helicopter snow blindness can be simulated, allowing researchers to intuitively observe the actual situation when snow blindness occurs, which is more in line with the problems faced in actual flight and provides a reliable practical basis for in-depth research on the snow blindness phenomenon.

[0070] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

Claims

1. A snow blindness test method for unmanned helicopters based on an outdoor cold environment, characterized in that: The specific steps include: S1. Select a test environment and test site that meets the test conditions; S2. Determine the safe flight conditions for the test based on the performance of the unmanned helicopter (1) and the limitations of the test environment and test site; S3. Unmanned helicopter (1) The operator shall conduct a test flight drill on a snow-free ground according to the determined flight conditions; and determine whether the existing snow on the test site meets the test requirements of being blown up by the rotor downwash to form a snow blindness scenario. If the snow condition meets the test requirements, proceed directly to step S4; The existing natural snow does not meet the test requirements, and measures need to be taken to make the snow on the ground meet the test requirements; S4. After determining the flight path of the unmanned helicopter (1) at the test site, install the equipment used for the test; S5. Conduct a pre-flight inspection of the unmanned helicopter (1); S6. Measure the physical properties of snow at the test site; S7. Conduct tests according to the determined flight conditions; S8. After the single vehicle test is completed, ensure that the unmanned helicopter (1) stops power output and check the status of the unmanned helicopter (1); S9. Measure the snow parameters at the test site again and record the impact of the unmanned helicopter (1) flight on the snow changes; S10. Confirm whether there are any remaining tests for the day; if there are any remaining tests for the day, proceed to S5; if the full-day test is completed, all the measuring equipment used for the test will be put away and stored indoors, and the unmanned helicopter (1) will be treated for corrosion; S11. Analyze the recorded data and evaluate the impact of meteorological environment, ground snow parameters, take-off weight of the unmanned helicopter (1) and flight conditions on the severity of snow blindness.

2. According to claim 1, a snow blindness test method for unmanned helicopters based on outdoor cold environment is characterized in that: The flight conditions in S2 include the take-off weight, flight trajectory, flight altitude, horizontal speed, vertical speed, and flight and hovering time of the unmanned helicopter (1).

3. The unmanned helicopter snow blindness test method based on outdoor cold environment according to claim 1 is characterized in that: When the existing natural snow in the test site described in S3 cannot meet the requirements of the snow blindness test, the following measures shall be taken: Physical method to loosen the snow layer: use mechanical equipment to directly act on the snow layer to loosen the snow layer by physical means; or, artificial snowmaking: use a snowmaking machine to artificially make snow, and then use a snowplow or snow shovel equipment to evenly distribute the snow generated by the snowmaking machine on the test site, thereby forming the loose snow conditions required for the test.

4. The unmanned helicopter snow blindness test method based on outdoor cold environment according to claim 1 is characterized in that: The equipment used in the test S4 includes a pan-tilt camera (2), a mobile weather station (3), an anemometer (4), and a camera (5); the pan-tilt camera (2) is installed on the front of the fuselage of the unmanned helicopter (1); the mobile weather station (3) is located in a safe position in the test site; When conducting vertical take-off and landing and hovering tests of the unmanned helicopter (1), the ground projection of the center of the main rotor hub of the unmanned helicopter (1) is used as the reference circle center, and a position within the range of two times the rotor radius is selected to arrange the anemometer (4), and the position of the camera (5) on the ground of the test site must ensure that the horizontal distance of the imaging field of the camera (5) is not less than six times the rotor radius; When conducting a forward flight test, the ground projection of the center of the main rotor hub of the unmanned helicopter (1) on the flight trajectory of the unmanned helicopter (1) is used as a ground reference trajectory line, and anemometers (4) are arranged at positions selected within a range of two times the rotor radius on both sides of the ground reference trajectory line. The installation position of the ground camera (5) in the test site is determined according to the ground reference trajectory line, and the horizontal distance of the imaging field of the camera (5) is not less than six times the rotor radius.

5. The unmanned helicopter snow blindness test method based on outdoor cold environment according to claim 1 is characterized in that: S6 The method for measuring the physical properties of snow on the test site specifically includes: Snow temperature measurement method: Use a probe-type temperature sensor to insert into the snow test area to obtain snow temperature data at different depths; Snow depth and density measurement method: Use a transparent snow density sampling measuring device to insert vertically downward from the top into the snow test area until it touches the ground. At this time, the measuring device has completed snow sampling. Seal the bottom of the measuring device with a cover plate, remove the snow, read the snow depth through the scale line on the transparent measuring device, and measure the weight of the snow in the container at the same time to get the overall density of the snow. Snow particle shape and size measurement method: Use an electron microscope with a scale to measure the shape and size of snow particles in the snow test area. The specific steps are: place the electron microscope outdoors to keep the snow particles in their original shape, turn on the power of the equipment, turn on the CCD camera and display screen, use the snow sample collection board to sample the snow particles to be measured and place them in the electron microscope observation area, adjust the LED source brightness, adjust the lens position so that the snow crystal image on the display screen is clear, collect and measure multiple sets of image information, and analyze the snow particle shape and particle size data.

6. The unmanned helicopter snow blindness test method based on outdoor cold environment according to claim 1 is characterized in that: The unmanned helicopter (1) needs to be equipped with a ground station and flight data collection, transmission and recording functions to achieve real-time monitoring of the flight status.

7. The unmanned helicopter snow blindness test method based on outdoor cold environment according to claim 6 is characterized in that: The unmanned helicopter (1) must be able to transmit the main rotor speed, collective pitch, and the position, altitude, heading, horizontal speed, and vertical speed of the unmanned helicopter (1) through a flight data recording system, wherein the position information of the unmanned helicopter (1) is provided by a GPS positioning system.

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