A method for positioning the wing deployment axis of a foldable UAV

Abstract

This invention belongs to the field of unmanned aerial vehicle (UAV) technology, specifically relating to a method for positioning the deployment axis of a foldable UAV wing surface. The method includes the following steps: S1, designing the aerodynamic shape of the deployed state according to the UAV's cruise conditions, and designing the dihedral angle and mounting angle of the wing surface according to maneuverability and stability; S2, designing the position of the wing surface in the folded state according to structural design requirements; S3, calculating the spatial orientation of a fixed rotation axis from the folded position to the deployed position, achieving the required dihedral angle and mounting angle of the wing or V-tail with a single rotation around the fixed axis from the folded position. This invention has the advantages that when the wing surface is folded, it fits tightly against the fuselage surface; when the wing surface is deployed, only one rotation around a fixed axis is needed to achieve the required dihedral angle and mounting angle for aerodynamic design.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) technology, specifically relating to a method for positioning the wing deployment axis of a foldable UAV. Background Technology

[0002] Small drones launched via swarms, swarm drones, mother-aircraft-dropped drones, and cannon-launched drones require deployment from the mother aircraft's weapons bay or launch from the launch tube. This necessitates folding the wings and tail fins within the mother aircraft's weapons bay or launch tube, and unfolding them after deployment or launch.

[0003] To achieve good maneuverability and stability, drones require their wing surfaces (including wings, V-tails, etc.) to have an upward dihedral angle and an angle of attack relative to the fuselage when deployed. Taking a certain type of drone's V-tail as an example... Figure 1 As shown. To achieve Figure 1 The dihedral angle and mounting angle shown represent the rotation of the wing surface around three mutually perpendicular axes in a Cartesian coordinate system, from its folded state to its unfolded state. Figures 2 to 5 As shown.

[0004] Conventional methods require three rotations around three axes to achieve the dihedral and mounting angles of the wing, significantly increasing system complexity and weight while reducing reliability. Therefore, existing folding drones have abandoned the dihedral and mounting angle design. The folding-unfolding of the wings / tails of existing small drones is similar to... Figure 6 and Figure 7 Two methods. Figure 6 The wings of the UAV are designed with overlapping, coaxial configurations, rotating around a vertical axis; the tail fin rotates around a horizontal axis. This configuration, once deployed, prevents the formation of dihedrals and angles of attack on the wing surfaces, severely limiting the aerodynamic design of the UAV. Figure 7 The aircraft employs a folding wing design on all four sides of the fuselage, which completely disrupts the aircraft's symmetry and reduces its maneuverability and stability. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for positioning the wing deployment axis of a foldable UAV. When the wing is folded, the wing is tightly attached to the fuselage surface; when the wing is deployed, only one rotation around a fixed axis is needed to achieve the dihedral and mounting angle required by the aerodynamic design.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A method for positioning the wing deployment axis of a foldable unmanned aerial vehicle (UAV) includes the following steps:

[0008] S1. Design the aerodynamic shape of the UAV in its deployed state according to the cruise conditions of the UAV, and design the dihedral angle and mounting angle of the wing surface according to the maneuverability and stability.

[0009] S2. Design the position of the folded wing surface according to the structural design requirements;

[0010] S3. Calculate the spatial orientation of the fixed rotation axis from the folded position to the unfolded position, so that the wing or V-tail can reach the unfolded position by one rotation around the fixed axis from the folded position, so that the wing or V-tail has the required dihedral angle and mounting angle.

[0011] In the folding UAV wing deployment axis positioning method provided by the present invention, preferably, the method for calculating the spatial orientation of the fixed rotation axis from the folded position to the deployed position in step S3 is as follows:

[0012] The folding position of the wing surface is designed according to the folding requirements; the transition from the folded state to the unfolded state involves three rotations, corresponding to the following three normalized quaternions:

[0013] A. Obtain the folding angle by rotating the folding position around the y-axis. , corresponding to quaternions:

[0014]

[0015] B. Rotate around the z-axis to obtain the reverse angle. , corresponding to quaternions:

[0016]

[0017] C. Then rotate around the x-axis to reach the final unfolded position, and obtain the installation angle. , corresponding to quaternions:

[0018]

[0019] Where i, j, and k are unit vectors in the x, y, and z axes, respectively;

[0020] S5. The quaternion corresponding to the rotation from the folded position to the unfolded position after one revolution around the fixed axis is:

[0021]

[0022] Using the quaternion arithmetic rules, we get:

[0023] (1)

[0024] Write the product of the above quaternions in the form of a scalar and vector sum.

[0025] (2)

[0026] make:

[0027]

[0028] It can be verified that:

[0029]

[0030] That is, equation (1) can always be written as equation (2);

[0031] but:

[0032]

[0033]

[0034] The obtained unit vector It is the unit vector in the direction of the axis of rotation; angle It is the angle from the folded position to the unfolded position by rotating once around the unit vector.

[0035] In the folding UAV wing deployment axis positioning method provided by the present invention, it is further preferred that the wing surface is an airfoil or a V-shaped tail.

[0036] In the folding UAV wing deployment axis positioning method provided by the present invention, it is further preferably that the folding angle is rotated around the y-axis from the folding position. It is 90°.

[0037] Compared with the prior art, the present invention has the following beneficial technical effects:

[0038] 1. When the wing is folded, it can fit tightly against the fuselage surface;

[0039] 2. When the wing is deployed, it only needs to rotate once around a fixed axis to achieve the dihedral and mounting angle required by the aerodynamic design.

[0040] 3. Since it only needs to rotate once around a fixed axis, the deployment mechanism is greatly simplified. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the dihedral and mounting angle on the wing surface;

[0042] Figures 2 to 5 This is a three-rotation method used in existing technologies to achieve the upper concave angle and the mounting angle;

[0043] Figure 6 and 7 This is a schematic diagram of the folding / unfolding of the wings of an existing drone.

[0044] Figures 8 to 12 This is a schematic diagram of the folding / unfolding of the wing surface around a fixed axis of the present invention;

[0045] Figure 13This is a schematic diagram of the wing surface of the present invention unfolding from the folded position to form an upper dihedral angle and an mounting angle. Detailed Implementation

[0046] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] This embodiment provides a method for positioning the wing deployment axis of a foldable unmanned aerial vehicle (UAV), including the following steps:

[0048] S1. Establish a rectangular coordinate system 0-xyz fixed to the wing or V-tail, such as Figure 13 As shown;

[0049] S2. First, based on the requirements of the deployed state and considering flight performance, design the dihedral angle of the wing surface. and installation angle ,like Figure 13 As shown in (d);

[0050] S3. Then, design the folding position of the wing surface according to the folding requirements, such as... Figure 13 As shown in (a), the process from the folded state to the unfolded state involved three rotations, corresponding to the following three normalized quaternions:

[0051] By fold position (e.g.) Figure 13 (a) shows the folding angle around the y-axis. (90°) Arrive Figure 13 (b) Position, corresponding to quaternion:

[0052]

[0053] Depend on Figure 13 (b) Position rotated around the z-axis at an upward angle arrive Figure 13 (c) Position, corresponding to the quaternion:

[0054]

[0055] Depend on Figure 13 (c) Position rotation around the x-axis at the mounting angle Reaching the final deployment position ( Figure 13 (d)), corresponding to the quaternion:

[0056]

[0057] Where i, j, and k are unit vectors in the x, y, and z axes, respectively.

[0058] Depend on Figure 13 The quaternion corresponding to one rotation from state a to state d is:

[0059]

[0060] Using the quaternion arithmetic rules, we get:

[0061] (1)

[0062] Write the product of the above quaternions in the form of a scalar and vector sum.

[0063] (2)

[0064] make:

[0065] (3)

[0066] It can be verified that:

[0067]

[0068] That is, equation (1) can always be written as equation (2).

[0069] but:

[0070] (4)

[0071] (5)

[0072] The obtained unit vector It is the unit vector in the direction of the axis of rotation; angle It is the angle from position a, rotating once around the unit vector to position d.

[0073] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for positioning the wing deployment axis of a foldable unmanned aerial vehicle (UAV), characterized in that, Includes the following steps: S1. Design the aerodynamic shape of the UAV in its deployed state according to the cruise conditions of the UAV, and design the dihedral angle and mounting angle of the wing surface according to the maneuverability and stability. S2. Design the position of the wing surface in the folding state according to the structural design requirements; S3. Calculate the spatial orientation of the fixed rotation axis from the folded position to the unfolded position, so that the wing or V-tail can reach the unfolded position by one rotation around the fixed axis from the folded position, so that the wing or V-tail has the required dihedral angle and mounting angle.

2. The method for positioning the wing deployment axis of a folding UAV according to claim 1, characterized in that, The method for calculating the spatial orientation of the fixed rotation axis from the folded position to the unfolded position, as described in step S3, is as follows: The folding position of the wing surface is designed according to the folding requirements; the transition from the folded state to the unfolded state involves three rotations, corresponding to the following three normalized quaternions: A. Obtain the folding angle by rotating the folding position around the y-axis. , corresponding to quaternions: B. Rotate around the z-axis to obtain the reverse angle. , corresponding to quaternions: C. Then rotate around the x-axis to reach the final unfolded position, and obtain the installation angle. , corresponding to quaternions: Where i, j, and k are unit vectors in the x, y, and z axes, respectively; S5. The quaternion corresponding to the position from the folded position to the unfolded position after rotating once around the fixed axis is: Using the quaternion arithmetic rules, we get: （1） Write the product of the above quaternions in the form of a scalar and vector sum. （2） make: It can be verified that: That is, equation (1) can always be written as equation (2); but: The obtained unit vector It is the unit vector in the direction of the axis of rotation; angle It is the angle from the folded position to the unfolded position by rotating once around the unit vector.

3. The method for positioning the wing deployment axis of a folding UAV according to claim 2, characterized in that, The wing surface is either an airfoil or a V-shaped tail.

4. The method for positioning the wing deployment axis of a folding UAV according to claim 3, characterized in that, Rotate the folding angle around the y-axis from the folding position It is 90°.

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