A turning control method based on wind speed compensation and vector superposition

Abstract

This application discloses a turning control method based on wind speed compensation and vector superposition. The method may include: Step 1: Determine true airspeed, and then calculate the real-time wind speed and direction; Step 2: Calculate the turn lead from the current segment to the next segment based on the current true airspeed, ground speed, and wind speed; Step 3: If the remaining flight distance of the current segment is not greater than the turn lead, initiate a fixed roll angle turn until the next segment is entered. The present invention achieves precise turning through wind speed compensation, thereby improving turning efficiency and control accuracy, avoiding overshoot and undershoot, and achieving the goal of accurately entering the route to be turned.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle (UAV) control, and more particularly to a turning control method based on wind speed compensation and vector superposition. Background Art

[0002] The routes of medium-to-large drones typically consist of a series of waypoints, each containing information such as longitude, latitude, altitude, and signatures. Based on the waypoint and leg information, the drone's remaining distance to fly and the leg's direction can be determined. The drone remains on course except during leg transitions. During these transitions, the drone employs a tangential turn, meaning it avoids using planned waypoints and makes a preemptive arc turn near the end of the leg to continue on to the next leg. The traditional turning process generally consists of three steps: First, the turning radius is calculated based on ground speed, and the remaining distance to fly is calculated based on longitude and latitude. When the remaining distance to fly is less than the turning radius, the drone proceeds to the next step. Second, the drone switches to directional flight mode, setting the heading angle for the next leg and beginning a roll at the designed turning gradient to the new heading. Third, when the difference between the actual and target headings falls below a threshold (e.g., 10°), the drone switches to follow-the-route control, correcting its lateral deviation until it fully adheres to the new route. In traditional control methods, the turning radius is usually given a fixed theoretical calculated value based on the circular motion formula and the turning slope. This ignores detailed factors such as the ground speed changes caused by the real-time wind field and the time it takes to roll to the turning slope angle. Therefore, it is difficult to achieve precise turns. When turning from flying against the wind to flying with the wind, a large overshoot will occur. When turning from flying with the wind to flying against the wind, the turn will end too early. Finally, the aircraft slowly enters the route by correcting the lateral deviation. The lateral deviation adjustment process is generally very slow and inefficient. In addition, certain payloads require the drone to maintain a stable flight state as much as possible, reduce attitude changes, and turn cleanly and in one step to avoid repeated attitude adjustments for a long time. Frequent rolling with long lateral deviation corrections will also affect the performance of the payload, thereby affecting the effectiveness of the entire mission. Therefore, it is necessary to develop a turning control method based on wind speed compensation and vector superposition.

[0003] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0004] The present invention proposes a turning control method based on wind speed compensation and vector superposition, which can achieve precise turning through wind speed compensation, thereby improving turning efficiency and control accuracy, avoiding turning overshoot and undershoot, and achieving the goal of accurately entering the route to be turned.

[0005] In a first aspect, an embodiment of the present disclosure provides a turning control method based on wind speed compensation and vector superposition, comprising:

[0006] Step 1: Determine the true airspeed and calculate the real-time wind speed and direction;

[0007] Step 2: Calculate the turn lead time from this segment to the next segment based on the current true airspeed, ground speed, and wind speed;

[0008] Step 3: If the remaining flight distance of this segment is not greater than the turn lead, start a fixed roll angle turn until entering the next segment.

[0009] Preferably, the true air speed is:

[0010]

[0011] Among them, TAS is true airspeed, IAS is indicated airspeed, p0 and T0 are the pressure and absolute temperature at sea level under standard atmosphere, respectively. h and T h are the atmospheric pressure and absolute temperature at height h, respectively.

[0012] Preferably, the wind speed and direction are calculated by the following formula:

[0013]

[0014] Where W is wind speed, Psi_W is wind direction, Psi_UAV is true airspeed direction, V d is the ground speed, ac_Psi is the track direction, and TAS is the true airspeed.

[0015] Preferably, calculating the turn lead time from the current segment to the next segment based on the current true airspeed, ground speed, and wind speed includes:

[0016] Calculate the true airspeed direction at the end of the turn, and then calculate the central angle of the circle through which the true airspeed turns during the turn;

[0017] Calculate true airspeed turning radius and thus the time required to turn;

[0018] Calculate the radius direction of the start and end of the turn, and then calculate the coordinates and length of the vector from the start to the end of the turn;

[0019] Calculate the angle between the next flight segment and the vector from the start turn to the end turn point, as well as the angle between the two flight segments, and then calculate the turn lead time.

[0020] Preferably, the true airspeed direction at the end of the turn is:

[0021] Psi_TAS_End=Psi_QR+sin -1(W×sin(Psi_QR-Psi_W) / TAS)

[0022] Among them, Psi_TAS_End is the true airspeed direction at the end of the turn.

[0023] Preferably, the length of the vector from the start turning point to the end turning point is:

[0024]

[0025] Among them, L is the length, A is the starting turning point, and C is the ending turning point.

[0026] Preferably, the angle between the next flight segment and the vector from the start turning point to the end turning point is:

[0027] a1=Psi_QR-Psi_AC

[0028] Among them, a1 is the next flight segment and Angle.

[0029] Preferably, the angle between the two flight segments is:

[0030] a2=180°-(Psi_QR-Psi_PQ)

[0031] Among them, a2 is the angle between the two flight segments.

[0032] Preferably, the turning advance amount is:

[0033]

[0034] Where L0 is the turn lead, gama is the roll bank angle, and ω is the roll angle rate during the roll action.

[0035] Preferably, it also includes:

[0036] If the remaining flight distance of this segment is greater than the turn advance amount, repeat steps 1-3.

[0037] Its beneficial effects are:

[0038] After applying this method, when the UAV switches and turns in the flight segment, the starting point of the turn can be calculated based on the wind field. At the end of the turn, the UAV just cuts into the waiting flight segment, without overshoot and insufficient turning. Precise turning improves the efficiency and accuracy of the UAV's turning, providing strong support for efficient mission execution.

[0039] The method of the present invention has other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and subsequent detailed description incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0041] Figure 1 The flowchart shows the steps of the turning control method based on wind speed compensation and vector superposition according to the present invention.

[0042] Figure 2 A flow chart showing the steps of a turning control method based on wind speed compensation and vector superposition according to an embodiment of the present invention is shown.

[0043] Figure 3 A schematic diagram showing a flight segment turn according to an embodiment of the present invention is shown.

[0044] Figure 4 A schematic diagram showing a synthesis relationship of turn end velocity vectors according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0046] To facilitate understanding of the solutions and effects of the embodiments of the present invention, a specific application example is given below. Those skilled in the art should understand that this example is only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0047] Example 1

[0048] Figure 1 The flowchart shows the steps of the turning control method based on wind speed compensation and vector superposition according to the present invention.

[0049] like Figure 1 As shown, the turning control method based on wind speed compensation and vector superposition includes:

[0050] Step 1: Determine the true airspeed and calculate the real-time wind speed and direction;

[0051] Step 2: Calculate the turn lead time from this segment to the next segment based on the current true airspeed, ground speed, and wind speed;

[0052] Step 3: If the remaining flight distance of this segment is not greater than the turn lead, start a fixed roll angle turn until entering the next segment.

[0053] In one example, true airspeed is:

[0054]

[0055] Among them, TAS is true airspeed, IAS is indicated airspeed, p0 and T0 are the pressure and absolute temperature at sea level under standard atmosphere, respectively. h and T h are the atmospheric pressure and absolute temperature at height h, respectively.

[0056] In one example, wind speed and direction are calculated as follows:

[0057]

[0058] Where W is wind speed, Psi_W is wind direction, Psi_UAV is true airspeed direction, V d is the ground speed, ac_Psi is the track direction, and TAS is the true airspeed.

[0059] In one example, based on the current true airspeed, ground speed, and wind speed, calculating the turn lead time from the current segment to the next segment includes:

[0060] Calculate the true airspeed direction at the end of the turn, and then calculate the central angle of the circle through which the true airspeed turns during the turn;

[0061] Calculate true airspeed turning radius and thus the time required to turn;

[0062] Calculate the radius direction of the start and end of the turn, and then calculate the coordinates and length of the vector from the start to the end of the turn;

[0063] Calculate the angle between the next flight segment and the vector from the start turn to the end turn point, as well as the angle between the two flight segments, and then calculate the turn lead time.

[0064] In one example, the true airspeed direction at the end of the turn is:

[0065] Psi_TAS_End=Psi_QR+sin -1 (W×sin(Psi_QR-Psi_W) / TAS)

[0066] Among them, Psi_TAS_End is the true airspeed direction at the end of the turn.

[0067] In one example, the length of the vector from the start turn to the end turn point is:

[0068]

[0069] Among them, L is the length, A is the starting turning point, and C is the ending turning point.

[0070] In one example, the angle between the next leg and the vector from the start turn to the end turn point is:

[0071] a1=Psi_QR-Psi_AC

[0072] Among them, a1 is the next flight segment and Angle.

[0073] In one example, the angle between two flight segments is:

[0074] a2=180°-(Psi_QR-Psi_PQ)

[0075] Among them, a2 is the angle between the two flight segments.

[0076] In one example, the turn lead is:

[0077]

[0078] Where L0 is the turn lead, gama is the roll bank angle, and ω is the roll angle rate during the roll action.

[0079] In one example, it also includes:

[0080] If the remaining flight distance of this segment is greater than the turn lead time, repeat steps 1-3.

[0081] Specifically, the wind compensation turning mode has a switch that can be set manually and a default value can be set. It can generally be set to be on by default. When the atmospheric engine fails or the satellite speed measurement is invalid, the flight control system cannot obtain the true airspeed or ground speed, and the drone will automatically turn off the wind compensation turning mode.

[0082] Figure 2 A flow chart showing the steps of a turning control method based on wind speed compensation and vector superposition according to an embodiment of the present invention is shown.

[0083] Step 1: Determine the indicated airspeed (IAS) and then obtain the true airspeed (TAS). The indicated airspeed (IAS) can be directly measured by the atmospheric engine, and the true airspeed can be directly obtained through the atmospheric engine output. If the atmospheric engine does not support direct output of the true airspeed, the true airspeed (TAS) can be calculated using the following formula:

[0084]

[0085] Among them, p0 and T0 are the pressure and absolute temperature at sea level under standard atmosphere, p h and T h are the atmospheric pressure and absolute temperature at an altitude of h, respectively. The true airspeed direction is from the aircraft towards Psi_UAV.

[0086] Step 2: Using the principle of vector superposition synthesis, according to the true airspeed TAS and ground speed V d The real-time wind speed W and wind direction Psi_W can be calculated:

[0087]

[0088] Figure 3 A schematic diagram showing a flight segment turn according to an embodiment of the present invention is shown.

[0089] By comprehensively utilizing tools and theories such as circular motion, vector superposition principle, plane geometry and trigonometric functions, the turn lead time L0 from the current segment to the next segment is calculated based on the current true airspeed, ground speed and wind speed, as follows: Figure 3 As shown in the figure, the drone turns from the PQ segment (n to n+1 segment) to the QR segment (n+1 to n+2 segment), with the starting turning point at point A and the ending turning point at point C. The calculation of the turn lead time includes the following steps:

[0090] Figure 4 A schematic diagram showing a synthesis relationship of turn end velocity vectors according to an embodiment of the present invention is shown.

[0091] Calculate the true airspeed direction Psi_TAS_End at the end of the turn. Figure 4 As shown in the figure, the velocity vector synthesis relationship at the end of the turn is magnified. At the end, the ground speed vector direction is the heading Psi_QR of the segment QR. The angle between the true airspeed and the ground speed vector can be obtained through trigonometric functions. Therefore, the true airspeed direction is:

[0092] Psi_TAS_End=Psi_QR+sin -1 (W×sin(Psi_QR-Psi_W) / TAS)

[0093] Calculate the central angle ∠AOB that true airspeed travels during the turn. The central angle is the difference between the true airspeed angles at the end of the turn and the beginning of the turn:

[0094] ∠AOB=Psi_TAS_End-Psi_UAV

[0095] Calculate the true airspeed turn radius OA and OB. According to the circular motion formula, the centripetal force is a component of gravity, the aircraft's bank angle is gama, and the turn radius is:

[0096]

[0097] Calculate the time t required to turn. Knowing the turning arc and speed, the time can be calculated as:

[0098]

[0099] The radius directions for calculating the start and end of a turn are:

[0100] Psi_OA=Psi_UAV-90°

[0101] Psi_OB=Psi_TAS_End-90°

[0102] Calculate vector In the vector coordinate system, the coordinates of the vector are fixed values ​​and have nothing to do with the position. The coordinates of the two vectors are:

[0103]

[0104] Calculate the vector of the aircraft's movement under the influence of wind speed during the actual turn The coordinates are:

[0105]

[0106] Calculate the vector from the start turning point to the end turning point The coordinates and length L. According to the principle of vector superposition, we can get:

[0107]

[0108] After obtaining the coordinates, the vector Direction Psi_AC and length

[0109] Calculate ΔAQC for two interior angles a1 and a2:

[0110] a1=Psi_QR-Psi_AC

[0111] a2=180-(Psi_QR-Psi_PQ)

[0112] Calculate the lead turn amount, L0. Applying the law of sines to ΔAQC yields the length of AQ, a theoretical value. In reality, it takes time for the aircraft to roll to the bank angle at the start of a turn and back to 0 degrees at the end of the turn. Therefore, a correction must be made to the lead turn amount. This correction is related to the aircraft's bank angle and roll rate. The lead turn amount, L0, is:

[0113]

[0114] Step 3: Calculate the remaining flight distance d from this segment to the next segment, and determine whether the remaining flight distance d is less than or equal to the turn lead value L0. If not, repeat the above steps. If so, the drone starts turning at a fixed roll angle and rolls to the turning bank angle until it enters the next segment. The turn ends and the normal roll angle is restored.

[0115] Those skilled in the art should understand that the above description of the embodiments of the present invention is only for the purpose of illustrative purposes only to illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0116] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A turning control method based on wind speed compensation and vector superposition, characterized in that: include: Step 1: Determine the true airspeed and calculate the real-time wind speed and direction; Step 2: Calculate the turn lead time from this segment to the next segment based on the current true airspeed, ground speed, and wind speed; Step 3: If the remaining flight distance of the current segment is not greater than the turn lead, start a fixed roll angle turn until entering the next segment; The calculation of the turn lead time from the current segment to the next segment based on the current true airspeed, ground speed, and wind speed includes: Calculate the true airspeed direction at the end of the turn, and then calculate the central angle of the circle through which the true airspeed turns during the turn; Calculate true airspeed turning radius and thus the time required to turn; Calculate the radius direction of the start and end of the turn, and then calculate the coordinates and length of the vector from the start to the end of the turn; Calculate the angle between the next flight segment and the vector from the start turn to the end turn point, as well as the angle between the two flight segments, and then calculate the turn lead time.

2. The turning control method based on wind speed compensation and vector superposition according to claim 1, wherein: The true airspeed is: Among them, TAS is true airspeed, IAS is indicated airspeed, and are the pressure and absolute temperature at sea level under standard atmosphere, and The heights are Atmospheric pressure and absolute temperature at the location.

3. The turning control method based on wind speed compensation and vector superposition according to claim 1, wherein: Calculate wind speed and direction using the following formula: Where W is wind speed, Psi_W is wind direction, Psi_UAV is true airspeed direction, V d is the ground speed, ac_Psi is the track direction, and TAS is the true airspeed.

4. The turning control method based on wind speed compensation and vector superposition according to claim 1, wherein: The true airspeed direction at the end of the turn is: in, is the true airspeed direction at the end of the turn, W is the wind speed, Psi_W is the wind direction, TAS is the true airspeed, and Psi_QR is the heading of segment QR.

5. The turning control method based on wind speed compensation and vector superposition according to claim 1, wherein: The length of the vector from the start point of the turn to the end point of the turn is: Among them, L is the length, A is the starting turning point, and C is the ending turning point.

6. The turning control method based on wind speed compensation and vector superposition according to claim 5, wherein: The angle between the next leg and the vector from the start turn to the end turn point is: Among them, a1 is the next flight segment and The angle between the two segments, Psi_QR is the heading of segment QR, and Psi_AC is the vector direction.

7. The turning control method based on wind speed compensation and vector superposition according to claim 6, wherein: The angle between the two flight segments is: Among them, a2 is the angle between the two flight segments.

8. The turning control method based on wind speed compensation and vector superposition according to claim 7, wherein: The turn lead time is: Among them, L0 is the turning lead time, is the rolling slope angle, is the roll angular rate during the roll action, V d is the ground speed.

9. The turning control method based on wind speed compensation and vector superposition according to claim 1, wherein: Also includes: If the remaining flight distance of this segment is greater than the turn advance amount, repeat steps 1-3.

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