Test method for measuring visual distance of cockpit passengers in snow field take-off and landing stage of helicopter

Abstract

The invention provides a test method for measuring the visual distance of passengers in a cockpit in the snow field take-off and landing stage of a helicopter, and belongs to the field of helicopter flight tests. The objective of the invention is to solve the problem that related researches are not developed in the technical fields of existing helicopter snow field flight and evaluation of the severity of cockpit view obstruction caused by snow blindness. The method comprises the following steps: S1, selecting a test environment and a test site meeting test conditions; s2, determining flight conditions; s3, test flight drilling; s4, test equipment is installed; s5, setting an identification target; s6, pasting a mark on the machine body; s7, measuring physical characteristics of accumulated snow on the test site; s8, checking before flight; s9, carrying out a test; s10, checking the state of the helicopter after the test is finished; s11, parameter measurement is carried out after completion; s12, arranging equipment after the test; and S13, analyzing the data. Through the method, an operable and followed flight test method and requirements can be provided for helicopter snow field flight and snow blindness research, and the method has important engineering application and guidance values.

Description

Technical Field

[0001] The invention relates to flight test technology, in particular to a test method for measuring the visual distance of cockpit crew members during the take-off and landing phase of a helicopter in snowy areas, and belongs to the field of helicopter flight test. Background Art

[0002] As helicopters are widely used in transportation and rescue missions in various special environments, when taking off, landing, or hovering close to the ground in polar regions or other snow-covered scenes, the interference between the main rotor and the ground forms a complex unsteady flow field. The strong rotor downwash will cause ground snow particles to roll up from near the rotor, inducing helicopter snow blindness, reducing visibility outside the cockpit, and obstructing the vision of the pilot and other passengers in the cockpit, making it impossible to judge the position of the ground and obstacles, seriously endangering the flight safety of the helicopter.

[0003] At present, most technical solutions to flight safety issues in low visibility environments focus on assisting the pilot in extending his visual range through onboard sensing equipment such as lidar and infrared cameras, or relying on specific flight procedures to avoid ground obstacles. No relevant research has been conducted in the technical field of helicopter flying in snowy areas and evaluating the severity of obstructed cockpit vision caused by snow blindness. Therefore, it is of great significance to provide an experimental research method that can measure the visual distance of cockpit occupants during takeoff and landing in snowy areas, conduct in-depth research on the impact of snow blindness under different working conditions on the visual range of cockpit occupants when helicopters fly in snowy environments, and provide visual distance measurement data under different environmental parameters. Summary of the invention

[0004] 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.

[0005] In view of this, in order to solve the problem that no relevant research has been carried out in the technical field of existing helicopter flying in snowy areas and evaluating the severity of obstructed cockpit vision caused by snow blindness, the present invention provides a test method for measuring the visual distance of cockpit occupants during the take-off and landing phase of helicopters in snowy areas.

[0006] The technical solution of the present invention is a test method for measuring the visual distance of cockpit occupants during the take-off and landing phase of a helicopter in snowy areas, which specifically comprises the following steps:

[0007] S1. Select a test environment and test site that meets the test conditions;

[0008] S2. Determine the safe flight conditions for the test based on the performance of the helicopter and the limitations of the test environment and test site;

[0009] S3. According to the flight conditions determined in S2, the helicopter pilot shall first conduct simulation training on the simulator, and then conduct test flights on the snow-free ground; 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;

[0010] S4. After confirming the helicopter test location at the test site, install the equipment used for the test;

[0011] S5. Set up identification targets at the test site;

[0012] S6. Paste graphic identification stickers and E-eye chart identification stickers on the helicopter fuselage;

[0013] S7. Measure the physical properties of snow at the test site;

[0014] S8. Conduct a pre-flight inspection of the helicopter to ensure that all systems and components are functioning properly; helicopter cockpit occupants must wear helmets with helmet cameras installed on the side of the helmets;

[0015] S9. Conduct tests according to the determined flight conditions;

[0016] S10. After the single vehicle test is completed, ensure that the helicopter stops power output and check the status of the helicopter;

[0017] S11. Measure the parameters of the test snow field again and record the impact of helicopter flight on snow cover changes;

[0018] S12. Confirm whether there are any remaining tests for the day; if there are any remaining test tasks for the day, proceed to S7, or proceed to S7 to continue the test after the snow condition changes; if the full-day test is over, all the measuring equipment used for the test will be collected and stored indoors;

[0019] S13. Analyze the test data and evaluate the effects of different test conditions on the severity of snow blindness.

[0020] Furthermore, the flight conditions in S2 include the take-off weight of the helicopter, a function of the change in helicopter altitude over time, a hovering altitude, and a hovering time.

[0021] 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:

[0022] 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.

[0023] Furthermore, the test equipment described in S4 includes a mobile weather station, a visibility meter and a camera.

[0024] Furthermore, the identification targets described in S5 are divided into printed identification targets and LED luminous identification targets; taking the ground projection of the center of the helicopter main rotor hub as a reference, no less than 3 identification targets are arranged at different distances and orientations.

[0025] Furthermore, the helicopter is a full-size manned helicopter and needs to be equipped with standard helicopter flight instruments.

[0026] Furthermore, the helicopter standard flight instruments include flight data recording equipment and meteorological sensors.

[0027] Furthermore, the length and width of the printed marking target are 1.5m*1m, the printed pattern is an E-shaped eye chart or graphics of different sizes, and the color of the printed pattern can be black or other bright colors.

[0028] Furthermore, the length and width dimensions of the LED light-emitting identification target are 1m*1m, and different colors and patterns can be displayed on the LED light-emitting identification target.

[0029] Furthermore, the length and width dimensions of the graphic identification sticker and the E-letter eye chart identification sticker are 1m*1m; the patterns of the graphic identification stickers are circular, square, or cross.

[0030] Furthermore, the method for measuring the physical properties of snow on the test site in S7 specifically includes:

[0031] 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;

[0032] 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.

[0033] 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.

[0034] Furthermore, the height of the helmet camera lens must be consistent with the eye height of the cockpit occupant.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention uses a full-size manned helicopter equipped with standard flight instruments to simulate snow blindness in an outdoor cold environment and snow-covered areas. By formulating a standardized test method for measuring the visual distance of cockpit occupants, the visual distance of the helicopter during takeoff and landing in a snowy environment can be accurately quantified, providing actionable flight safety assessment data.

[0037] 2. The present invention provides technical support for the safe flight of helicopters in special scenarios such as polar regions and in all-weather environments, and provides an operational and followable flight test method and requirements for subsequent domestic helicopter snow-field flight and snow blindness research, which has important engineering applications and guiding value. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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:

[0039] Figure 1 This is a flow chart of a test method for measuring the visual distance of cockpit crew members during helicopter takeoff and landing in snowy areas;

[0040] Figure 2 Provide a bird's-eye view of the test site equipment layout;

[0041] Figure 3 This is a schematic diagram of the ground marking target;

[0042] Figure 4 A schematic diagram of a helicopter with a sticker on it;

[0043] Figure 5 Schematic diagram of the equipment worn by cockpit crew members.

[0044] In the figure: 1-helicopter, 2-mobile weather station, 3-visibility meter, 4-marking target, 5-ground personnel, 6-camera, 7-printed marking target, 8-LED luminous marking target, 9-graphic marking sticker, 10-E-eye chart marking sticker, 11-cockpit crew, 12-helmet, 13-helmet camera. DETAILED DESCRIPTION

[0045] 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.

[0046] Example 1, reference Figure 1-5 The present embodiment is described as follows: a test method for measuring the visual distance of a helicopter cockpit occupant during takeoff and landing in snowy areas, specifically comprising the following steps:

[0047] S1. Select a test environment and test site that meets the test conditions:

[0048] 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 helicopter 1, the test site needs to have enough space;

[0049] S2. Determine the flight conditions for test safety based on the performance of helicopter 1 and the limitations of the test environment and test site;

[0050] S3. According to the flight conditions determined in S2, the pilot of helicopter 1 first conducts simulation training on the simulator, and then conducts a test flight exercise on the snow-free ground; judge 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;

[0051] S4. After confirming the test position of Helicopter 1 at the test site, install the equipment used for the test:

[0052] After confirming the test position of helicopter 1, select a safe position to install mobile weather station 2 and visibility meter 3; take the ground projection of the center of the main rotor hub of helicopter 1 as the reference, arrange cameras 6 at different distances on the front side and left and right sides of the fuselage;

[0053] S5. Set the target 4 at the test site;

[0054] S6. Paste graphic identification sticker 9 and E-eye chart identification sticker 10 on the fuselage of the helicopter 1;

[0055] S7. Measure the physical properties of snow at the test site;

[0056] S8. Perform a pre-flight inspection of the helicopter 1 to ensure the normal operation of various systems and components; the helicopter cockpit occupant 11 needs to wear a helmet 12, and a helmet camera 13 is installed on the side of the helmet 12;

[0057] S9. Conduct tests according to the determined flight conditions:

[0058] A laser rangefinder is used at the location of the identification target 4 to accurately measure the distance between the identification target 4 and the helicopter; under the guidance of the ground personnel 5, the cockpit crew 11 respectively identifies the printed identification targets 7 at different distances and different orientations, and records the letter sizes that can be clearly identified by the printed identification targets 7; the LED light-emitting identification targets 8 are controlled to display different colors and patterns, and the pattern size is gradually reduced, and the pattern size that can be clearly identified when different colors are used is recorded;

[0059] The LED light-emitting identification target 8 is randomly transformed into different images for the cockpit personnel to identify, and the recognition reaction time of the cockpit occupant 11 to the ground objects under the influence of snow blindness is tested; at the same time, the ground personnel 5 observe the graphic identification sticker 9 and the E-letter eye chart identification sticker 10 on the fuselage of the helicopter 1 at the location where the camera 6 is arranged, and record the letters and graphic sizes that can be clearly identified;

[0060] Since people's pattern recognition behavior is subjective, it is necessary to change personnel to conduct multiple tests to obtain the average value of the visual distance. At the same time, the information recorded by the helmet camera 13 and the camera 6 is also used for the later objective evaluation of the impact of snow blindness on cockpit visibility;

[0061] S10. After the single vehicle test is completed, ensure that helicopter 1 stops power output and check the status of helicopter 1;

[0062] S11. Measure the parameters of the test snow field again and record the impact of the flight of helicopter 1 on the change of snow accumulation;

[0063] S12. Confirm whether there are any remaining tests for the day; if there are any remaining test tasks for the day, proceed to S7, or proceed to S7 to continue the test after the snow condition changes; if the full-day test is over, all the measuring equipment used for the test will be collected and stored indoors;

[0064] S13. Analyze the test data and evaluate the impact of different test conditions on the severity of snow blindness:

[0065] The visual distance data of the cockpit crew 11 during the test is processed, and the collected image information can objectively verify the law and analyze the influence of different environments, different snow parameters, different aircraft gross weights, and different flight conditions on the snow blindness of the helicopter 1 and the visual field of the cockpit crew 11;

[0066] Based on the test results, the visibility and safety of helicopter take-off and landing in snowy environment are evaluated, and suggestions for optimizing the visual distance of cockpit crew members are put forward.

[0067] Furthermore, the flight conditions in S2 include the take-off weight of the helicopter 1, the function of the height variation of the helicopter 1 over time, the hovering height and the hovering time.

[0068] 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:

[0069] 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.

[0070] Furthermore, the test equipment in S4 includes a mobile weather station 2, a visibility meter 3 and a camera 6.

[0071] Furthermore, the identification target 4 described in S5 is divided into a printed identification target 7 and an LED luminous identification target 8; taking the ground projection of the center of the main rotor hub of the helicopter 1 as a reference, no less than 3 identification targets 4 are arranged at different distances and orientations.

[0072] Furthermore, the helicopter 1 is a full-size manned helicopter and needs to be equipped with standard helicopter flight instruments.

[0073] Furthermore, the standard flight instruments of the helicopter 1 include a flight data recorder and a meteorological sensor.

[0074] Furthermore, the length and width of the printed plate marking target 7 are 1.5m*1m, the printed pattern is selected from the E-letter eye chart or graphics of different sizes, and the color of the printed pattern can be black or other bright colors.

[0075] Furthermore, the length and width dimensions of the LED light-emitting identification target 8 are 1m*1m, and different colors and patterns can be displayed on the LED light-emitting identification target 8.

[0076] Furthermore, the graphic identification sticker 9 and the E-letter eye chart identification sticker 10 have a length and width of 1m*1m; the pattern of the graphic identification sticker 9 is circular, square, or cross.

[0077] Furthermore, the method for measuring the physical properties of snow on the test site in S7 specifically includes:

[0078] 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;

[0079] 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.

[0080] 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.

[0081] Furthermore, the lens height of the helmet camera 13 needs to be consistent with the eye height of the cockpit occupant 11.

[0082] Through the present invention, a full-size manned helicopter equipped with standard flight instruments can be used to simulate snow blindness based on an outdoor cold environment and a snow-covered area. By formulating a standardized cockpit occupant visual distance measurement test method, the visual distance of the helicopter during takeoff and landing in a snowy environment can be accurately quantified, providing operational flight safety assessment data.

[0083] Through this invention, technical support is provided for the safe flight of helicopters in special scenarios such as the polar regions and in all-weather environments, and an operational and followable flight test method and requirements are provided for subsequent domestic helicopter snow-field flight and snow blindness research, which has important engineering applications and guiding value.

[0084] 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 test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas, characterized in that: The specific steps include: S1. Select a test environment and test site that meets the test conditions; S2. Determine the flight conditions for test safety based on the performance of the helicopter (1) and the limitations of the test environment and test site; S3. According to the flight conditions determined in S2, the helicopter pilot (1) first performs simulation training on the simulator, and then conducts a test flight exercise on snow-free ground; determines whether the existing snow at 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; 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 confirming the test position of the helicopter (1) at the test site, install the equipment used for the test; S5. Setting a target marker at the test site (4); S6. Paste a graphic identification sticker (9) and an E-shaped eye chart identification sticker (10) on the helicopter (1) fuselage; S7. Measure the physical properties of snow at the test site; S8. Perform a pre-flight inspection of the helicopter (1) to ensure that all systems and components are functioning properly; the helicopter (1) cockpit occupant (11) is required to wear a helmet (12), and a helmet camera (13) is installed on the side of the helmet (12); S9. Conduct tests according to the determined flight conditions; S10. After the single vehicle test is completed, ensure that the helicopter (1) stops power output and check the status of the helicopter (1); S11. Measure various parameters of the test snow field again and record the effect of the helicopter (1) flight on the change of snow accumulation; S12. Confirm whether there are any remaining tests for the day; if there are any remaining test tasks for the day, proceed to S7, or proceed to S7 to continue the test after the snow condition changes; if the full-day test is over, all the measuring equipment used for the test will be collected and stored indoors; S13. Analyze the test data and evaluate the effects of different test conditions on the severity of snow blindness.

2. According to claim 1, a test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas, characterized in that: The flight conditions in S2 include the take-off weight of the helicopter (1), a function of the change in the height of the helicopter (1) over time, the hovering height, and the hovering time.

3. According to the test method of claim 1, the visual distance measurement of cockpit occupants during helicopter takeoff and landing in snowy areas is characterized by: 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: Snow can be artificially made by a snowmaking machine, and then a snowplow or snow shovel equipment is used 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. According to the test method of claim 1, the visual distance measurement of cockpit occupants during helicopter takeoff and landing in snowy areas is characterized by: S4 The test equipment includes a mobile weather station (2), a visibility meter (3) and a camera (6).

5. According to claim 1, a test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas, characterized in that: S5 The identification target (4) is divided into a printed identification target (7) and an LED luminous identification target (8); taking the ground projection of the center of the main rotor hub of the helicopter (1) as a reference, no less than three identification targets (4) are arranged at different distances and different orientations.

6. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 1 is characterized in that: The helicopter (1) is a full-size manned helicopter and needs to be equipped with standard helicopter flight instruments.

7. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 6 is characterized in that: The standard flight instruments of the helicopter (1) include flight data recording equipment and meteorological sensors.

8. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 1 is characterized in that: The printed marking target (7) has a length and width of 1.5m*1m, and the printed pattern is selected from an E-shaped eye chart or graphics of different sizes, and the color of the printed pattern can be black or other bright colors.

9. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 1 is characterized in that: The LED light-emitting identification target (8) has a length and width of 1 m*1 m, and different colors and patterns can be displayed on the LED light-emitting identification target (8).

10. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 1, characterized in that: The graphic identification sticker (9) and the E-shaped eye chart identification sticker (10) have a length and width of 1m*1m; the pattern of the graphic identification sticker (9) is circular, square or cross-shaped.

11. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 1, characterized in that: S7 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 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.

12. The test method for measuring the visual distance of cockpit occupants during helicopter takeoff and landing in snowy areas according to claim 1, characterized in that: The lens height of the helmet camera (13) must be consistent with the eye height of the cockpit occupant (11).

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