Method and device for determining that an unmanned helicopter has reached a sideslip envelope

Abstract

The application provides a method and device for judging whether an unmanned helicopter reaches a side slip envelope, and the method comprises the following steps: obtaining a current roll angle and true airspeed of the unmanned helicopter; determining whether the roll angle of the unmanned helicopter reaches a roll angle envelope corresponding to the true airspeed according to a preset roll angle envelope chart; if yes, determining that the unmanned helicopter reaches the side slip envelope, otherwise, determining that the unmanned helicopter does not reach the side slip envelope; wherein the preset roll angle envelope chart is drawn according to a side slip angle envelope chart. The user of the unmanned helicopter can determine whether the side slip angle exceeds the side slip envelope when the unmanned helicopter is flying according to the calculation result, so that the flight safety of the user using the unmanned helicopter is ensured.

Description

Technical Field

[0001] This invention belongs to the field of helicopter technology, specifically relating to a method and apparatus for determining whether an unmanned helicopter has reached its sideslip envelope. Background Technology

[0002] Helicopters are limited by envelopes such as altitude, speed, and sideslip during flight, each playing a crucial role. In flight, the helicopter's sideslip angle refers to the situation where the incoming airflow direction is not aligned with the helicopter's longitudinal axis. The sideslip envelope defines the maximum range of sideslip angles a helicopter can withstand under different flight conditions and is used in the design phase for flight spectrum compilation, flight load calculation, and component life assessment to ensure flight safety and stability. Therefore, it is essential to determine whether the helicopter's sideslip angle has reached the sideslip envelope during flight.

[0003] To measure the sideslip angle of a helicopter during flight, a sideslip ball or a pitot tube with a sideslip indicator is typically used. However, the accuracy of a sideslip ball is affected by wind speed and direction, and due to its operating principle, it can only roughly indicate the sideslip direction and angle. Therefore, sideslip balls are only used on manned helicopters. A pitot tube with a sideslip indicator can better measure the sideslip angle of a helicopter during flight, but this device increases the cost of the helicopter, which is detrimental to its market competitiveness. Summary of the Invention

[0004] This invention proposes a method and apparatus for determining whether an unmanned helicopter has reached its sideslip envelope. This method can determine the sideslip angle during helicopter flight, reduce helicopter costs, and can be applied to unmanned helicopters that are not equipped with sensors to measure the sideslip angle.

[0005] The first aspect of the present invention provides a method for determining whether an unmanned helicopter has reached its sideslip envelope, comprising: Obtain the current roll angle and vacuum velocity of the unmanned helicopter; Based on the preset roll angle envelope chart, determine whether the roll angle of the unmanned helicopter reaches the roll angle envelope corresponding to the vacuum speed; If the sideslip envelope is reached, it is determined that the unmanned helicopter has reached the sideslip envelope; otherwise, it is determined that the unmanned helicopter has not reached the sideslip envelope. The preset roll angle envelope chart is drawn based on the sideslip angle envelope chart.

[0006] Optionally, the roll angle ϕ envelope corresponding to the vacuum speed Vt is determined based on the sideslip angle β envelope corresponding to the vacuum speed Vt and the formula β=arcsin[(ϕ-ϕ0)*a / Vt]; ϕ0 is the forward roll angle corresponding to the vacuum speed Vt in the absence of wind and lateral ground speed, and a is the wind resistance capability corresponding to a 1° roll angle change of the unmanned helicopter.

[0007] Optional, ϕ0 = (ϕ01 + ϕ02) / 2; ϕ01 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle ψ, ϕ01 = (ϕ1 + ϕ2) / 2; ϕ1 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed V1, and sideslip angle β; ϕ2 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed -V1, and sideslip angle -β. ϕ02 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle (360°-ψ), ϕ02=(ϕ3+ϕ4) / 2; ϕ3 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β; ϕ4 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β.

[0008] Optional, a = 2V1 / (ϕ1 - ϕ2).

[0009] Optionally, methods for determining whether an unmanned helicopter has reached its sideslip envelope may also include: Obtain the predicted wind resistance capacity a1=2V1 / (ϕ1-ϕ2) and the predicted wind resistance capacity a2=2V3 / (ϕ3-ϕ4); When the difference between a1 and a2 exceeds the preset range, ϕ1, ϕ2, ϕ3 and ϕ4 are reacquired.

[0010] A second aspect of the present invention provides a device for determining whether an unmanned helicopter has reached its sideslip envelope, comprising: The acquisition module is used to acquire the current roll angle and vacuum velocity of the unmanned helicopter; The lookup module is used to determine whether the roll angle of the unmanned helicopter has reached the roll angle envelope corresponding to the vacuum speed based on a preset roll angle envelope chart; if it has, it is determined that the unmanned helicopter has reached the sideslip envelope; otherwise, it is determined that the unmanned helicopter has not reached the sideslip envelope. The preset roll angle envelope chart is drawn based on the sideslip angle envelope chart.

[0011] Optionally, the roll angle ϕ envelope corresponding to the vacuum speed Vt is determined based on the sideslip angle β envelope corresponding to the vacuum speed Vt and the formula β=arcsin[(ϕ-ϕ0)*a / Vt]; ϕ0 is the forward roll angle corresponding to the vacuum speed Vt in the absence of wind and lateral ground speed, and a is the wind resistance capability corresponding to a 1° roll angle change of the unmanned helicopter.

[0012] Optional, ϕ0 = (ϕ01 + ϕ02) / 2; ϕ01 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle ψ, ϕ01 = (ϕ1 + ϕ2) / 2; ϕ1 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed V1, and sideslip angle β; ϕ2 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed -V1, and sideslip angle -β. ϕ02 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle (360°-ψ), ϕ02=(ϕ3+ϕ4) / 2; ϕ3 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β; ϕ4 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β.

[0013] Optional, a = 2V1 / (ϕ1 - ϕ2).

[0014] Optionally, the device for determining whether an unmanned helicopter has reached its sideslip envelope also includes: a calibration module; The calibration module is used to obtain the predicted wind resistance capacity a1=2V1 / (ϕ1-ϕ2) and the predicted wind resistance capacity a2=2V3 / (ϕ3-ϕ4); when the difference between a1 and a2 exceeds the preset range, ϕ1, ϕ2, ϕ3 and ϕ4 are re-obtained.

[0015] This invention proposes a method and apparatus for determining whether an unmanned helicopter has reached its sideslip envelope. By utilizing flight data from test flights and parameters such as lateral ground speed and roll angle, the method calculates the wind resistance corresponding to a 1° roll angle at the current speed and the sideslip angle during flight. This allows for a better determination of whether the sideslip angle of the unmanned helicopter is within the sideslip envelope, ensuring flight safety. The calculation method proposed in this invention is based on existing parameters in the unmanned helicopter's flight parameter data, eliminating the need for additional sensors to measure the sideslip angle, thus saving on testing and measurement costs and improving the economic efficiency and market competitiveness of the unmanned helicopter. The method and apparatus proposed in this invention can be completed during the development and test flight of the unmanned helicopter. The results calculated during this period can be directly applied to the unmanned helicopters delivered to customers. Users can directly utilize these results to determine whether the sideslip angle exceeds the sideslip envelope, ensuring flight safety for customers using the unmanned helicopter. Attached Figure Description

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

[0017] Figure 1 This invention provides a manual entry process for small groups; Figure 2 This is a schematic diagram of the side-slip envelope of the present invention; Figure 3 This is a schematic diagram illustrating the roll angle range used in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0020] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0021] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0023] like Figure 1-3 As shown, this invention uses preliminary test flight data to calculate the forward roll angle of the unmanned helicopter at different speeds in windless and sideslip-free conditions, as well as the wind resistance corresponding to a 1° roll angle change. The roll angle during unmanned helicopter flight is used to determine whether the sideslip angle is within the designed sideslip envelope, thereby ensuring the flight safety of the unmanned helicopter.

[0024] The method of this invention is as follows: The unmanned helicopter performs left and right sideslip flights with a vacuum speed Vt, a heading angle ψ, and (360-ψ) respectively, a lateral ground speed V, and sideslip angles β and -β. Figure 1 As shown in Table 1, four sets of data were obtained for the left and right lateral sliding motion at a vacuum velocity Vt: Table 1. Round-trip data for left and right lateral sliding.

[0025] The same applies to other flight speeds.

[0026] a) Based on the data in Table 1, left and right sideslips were performed at heading angles ψ with lateral ground speeds V1 and -V1 and sideslip angles β and -β. The roll angle corresponding to a lateral ground speed of 0 at heading angle ψ was obtained based on the lateral ground speed during the round trip flight: ϕ01 = (ϕ1 + ϕ2) / 2; b) Based on the data in Table 1, left and right sideslips were performed at a heading angle (360-ψ) with lateral ground speeds V3 and -V3 and sideslip angles β and -β. The roll angle corresponding to a lateral ground speed of 0 at a heading angle (360-ψ) was obtained based on the lateral ground speed during the round trip flight: ϕ02 = (ϕ3 + ϕ4) / 2; c) Since it is difficult to judge the changes in wind direction and speed in the air, the roll angle of the unmanned helicopter at vacuum speed Vt can be roughly judged by combining historical test flight data. If the calculated ϕ01 and ϕ02 are close to the historical test flight data, it can be considered that the wind direction and speed are roughly the same when the two sideslip flight is under the two directions. If the calculated ϕ01 and ϕ02 are significantly different from the historical test flight data, it can be considered that the wind direction and speed have changed significantly when sideslip flight. In this case, the data point should be removed and a suitable data point should be selected for recalculation. d) Based on the roll angles ϕ01 and ϕ02 corresponding to the lateral ground speed 0 at the ψ heading angle and (360-ψ) heading angle respectively, obtained from the above calculations, the average value of the roll angles corresponding to the lateral ground speed 0 at the opposite heading can be calculated, which is the forward roll attitude corresponding to the windless and sideslip-free state. Similarly, the forward roll angles corresponding to the windless and sideslip-free state at different speeds can be calculated, as shown in Table 2.

[0027] ϕ0 = (ϕ01 + ϕ02) / 2 Table 2 Roll angles at different speeds without wind or sideslip

[0028] e) Based on the above calculations, the wind resistance capability of an unmanned helicopter corresponding to a 1° roll angle change at vacuum velocity Vt can be obtained: The wind resistance capability of a 1° roll angle change when flying at a heading angle ψ = 2V1 / (ϕ1-ϕ2). The wind resistance capability of a 1° roll angle change when flying at a heading angle of (360-ψ) = 2V3 / (ϕ3-ϕ4); f) If the wind resistance capability of a 1° roll angle change under the heading angle ψ is not significantly different from that under the heading angle (360-ψ), it indicates that the lateral wind speed did not change significantly when performing left and right sideslip flight under the same heading angle. In this case, the data point is appropriate, and the average of the two can be taken as the wind resistance capability of a 1° roll angle change when flying at vacuum speed Vt. If the wind resistance capability of a 1° roll angle change under the heading angle ψ is significantly different from that under the heading angle (360-ψ), it indicates that the wind speed and direction in the air changed significantly during left and right sideslip flight under a certain heading angle. In this case, the data point cannot be used for calculation and should be removed and a suitable data point should be selected for calculation. g) In the ψ direction, the roll angle ϕ01 corresponding to no ground speed sideslip minus the roll angle ϕ0 corresponding to no wind and no sideslip is the change in roll angle caused by crosswind. Multiply this by the wind resistance corresponding to a 1° roll angle change, and the result is the crosswind magnitude in the ψ direction. h) Based on the crosswind calculated above, plus the lateral velocity of the aircraft, the aerodynamic sideslip angle of the unmanned helicopter during flight can be calculated: Aerodynamic sideslip angle = arcsin[(ϕ-ϕ0)*a / Vt]; ϕ: The real-time roll angle during flight; ϕ0: The forward roll angle corresponding to no wind, no lateral ground speed, and vacuum speed Vt.

[0029] ϕ0 = (ϕ01 + ϕ02) / 2 ϕ01: The roll angle ϕ1 is obtained by sideslipping at vacuum speed Vt with heading angle ψ, lateral ground speed V1, and sideslip angle β. The roll angle ϕ2 is obtained by sideslipping with lateral ground speed -V1 and sideslip angle -β. The roll angle ϕ01 corresponding to the lateral ground speed of 0 is obtained based on the lateral ground speed of the round trip flight. ϕ01 = (ϕ1 + ϕ2) / 2; ϕ02: The roll angle ϕ3 is obtained by sideslipping at vacuum speed Vt with heading angle (360-ψ), lateral ground speed V3, and sideslip angle β. The roll angle ϕ4 is obtained by sideslipping with lateral ground speed -V3 and sideslip angle -β. Based on the lateral ground speed during the round trip, the roll angle ϕ02 corresponding to a lateral ground speed of 0 is derived. ϕ02 = (ϕ3 + ϕ4) / 2; Wind resistance corresponding to a = 2V1 / (ϕ1-ϕ2)1° roll angle i) Based on the sideslip angle calculated above, compare it with the sideslip angle range at vacuum speed Vt in the sideslip flight envelope of the unmanned helicopter. If the sideslip angle is less than the sideslip angle envelope at vacuum speed Vt, the unmanned helicopter is flying within the sideslip angle envelope; if the sideslip angle is greater than the sideslip angle envelope at vacuum speed Vt, the unmanned helicopter has exceeded the sideslip angle envelope and needs to make timely corrections to ensure that the sideslip angle is within the envelope range, thereby ensuring the flight safety of the unmanned helicopter. j) Similarly, following the calculation method described above, based on the forward roll angle of the unmanned helicopter at different speeds without wind or sideslip and the wind resistance corresponding to a 1° roll angle change, the allowable roll angle of the unmanned helicopter flying within the sideslip envelope can be calculated, such as... Figure 3 As shown, the flight roll angle is used to determine whether the unmanned helicopter is flying within the sideslip envelope, thus ensuring the flight safety of the unmanned helicopter.

[0030] This invention proposes a method and apparatus for determining whether an unmanned helicopter has reached its sideslip envelope. By using flight data during test flights and parameters such as lateral ground speed and roll angle, the wind resistance corresponding to a 1° roll angle at the current speed and the sideslip angle during flight are calculated. This method can better determine whether the sideslip angle of the unmanned helicopter is within the sideslip envelope during flight, thus ensuring the flight safety of the unmanned helicopter.

[0031] The calculation method proposed in this invention is based on the parameters already present in the flight parameter data of unmanned helicopters. It does not require the installation of sensors to measure the sideslip angle, thus saving the testing and measurement costs of unmanned helicopters and improving their economic efficiency and market competitiveness.

[0032] The method and apparatus proposed in this invention can be completed during the development and test flight of unmanned helicopters. The results calculated during the development and test flight of unmanned helicopters can be directly applied to the unmanned helicopters delivered to customers. That is, unmanned helicopter users can directly apply the results. Based on the calculation results, unmanned helicopter users can determine whether the sideslip angle of the unmanned helicopter exceeds the sideslip envelope during flight, thus ensuring the flight safety of customers using unmanned helicopters.

[0033] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for determining whether an unmanned helicopter has reached its sideslip envelope, characterized in that, include: Obtain the current roll angle and vacuum velocity of the unmanned helicopter; Based on the preset roll angle envelope chart, determine whether the roll angle of the unmanned helicopter reaches the roll angle envelope corresponding to the vacuum speed; If the sideslip envelope is reached, it is determined that the unmanned helicopter has reached the sideslip envelope; otherwise, it is determined that the unmanned helicopter has not reached the sideslip envelope. The preset roll angle envelope chart is drawn based on the sideslip angle envelope chart.

2. The method for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 1, characterized in that, The envelope of the roll angle ϕ corresponding to the vacuum speed Vt is determined based on the envelope of the sideslip angle β corresponding to the vacuum speed Vt and the formula β=arcsin[(ϕ-ϕ0)*a / Vt]; ϕ0 is the forward roll angle corresponding to the vacuum speed Vt in the absence of wind and lateral ground speed, and a is the wind resistance capability corresponding to a 1° change in roll angle of the unmanned helicopter.

3. The method for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 2, characterized in that, ϕ0 = (ϕ01 + ϕ02) / 2; ϕ01 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle ψ, ϕ01 = (ϕ1 + ϕ2) / 2; ϕ1 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed V1, and sideslip angle β; ϕ2 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed -V1, and sideslip angle -β. ϕ02 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle (360°-ψ), ϕ02=(ϕ3+ϕ4) / 2; ϕ3 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β; ϕ4 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β.

4. The method for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 2, characterized in that, a = 2V1 / (ϕ1-ϕ2) 5. The method for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 2, characterized in that, The method further includes: Obtain the predicted wind resistance capacity a1=2V1 / (ϕ1-ϕ2) and the predicted wind resistance capacity a2=2V3 / (ϕ3-ϕ4); When the difference between a1 and a2 exceeds the preset range, ϕ1, ϕ2, ϕ3 and ϕ4 are reacquired.

6. A device for determining whether an unmanned helicopter has reached its sideslip envelope, characterized in that, include: The acquisition module is used to acquire the current roll angle and vacuum velocity of the unmanned helicopter; The lookup module is used to determine whether the roll angle of the unmanned helicopter has reached the roll angle envelope corresponding to the vacuum speed based on a preset roll angle envelope chart; if it has, it is determined that the unmanned helicopter has reached the sideslip envelope; otherwise, it is determined that the unmanned helicopter has not reached the sideslip envelope. The preset roll angle envelope chart is drawn based on the sideslip angle envelope chart.

7. The device for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 6, characterized in that, The envelope of the roll angle ϕ corresponding to the vacuum speed Vt is determined based on the envelope of the sideslip angle β corresponding to the vacuum speed Vt and the formula β=arcsin[(ϕ-ϕ0)*a / Vt]; ϕ0 is the forward roll angle corresponding to the vacuum speed Vt in the absence of wind and lateral ground speed, and a is the wind resistance capability corresponding to a 1° change in roll angle of the unmanned helicopter.

8. The device for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 7, characterized in that, ϕ0 = (ϕ01 + ϕ02) / 2; ϕ01 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle ψ, ϕ01 = (ϕ1 + ϕ2) / 2; ϕ1 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed V1, and sideslip angle β; ϕ2 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle ψ, lateral ground speed -V1, and sideslip angle -β. ϕ02 is the roll angle of the unmanned helicopter when the lateral ground speed is 0 under vacuum speed Vt and heading angle (360°-ψ), ϕ02=(ϕ3+ϕ4) / 2; ϕ3 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β; ϕ4 is the roll angle obtained by the unmanned helicopter sideslipping under vacuum speed Vt, heading angle (360°-ψ), lateral ground speed V3, and sideslip angle β.

9. The device for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 7, characterized in that, a = 2V1 / (ϕ1-ϕ2) 10. The device for determining whether an unmanned helicopter has reached its sideslip envelope according to claim 7, characterized in that, Also includes: Proofreading module; The calibration module is used to obtain the predicted wind resistance capacity a1=2V1 / (ϕ1-ϕ2) and the predicted wind resistance capacity a2=2V3 / (ϕ3-ϕ4); when the difference between a1 and a2 exceeds the preset range, ϕ1, ϕ2, ϕ3 and ϕ4 are re-obtained.

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