Two-dimensional trajectory correction mechanism based on electromagnetic damping

Abstract

The application discloses a two-dimensional trajectory correction mechanism based on electromagnetic damping, which can be used for trajectory correction of high-rotation stable ammunition. The phase control of the rudder blade is realized through an electromagnetic damping mechanism, and the rudder angle control is realized through an electromagnet, so that the fusion of the fixed canard rudder and the movable canard rudder is realized in a low-cost mode. Because the two canard rudders are combined, the guidance law is more extensive. The traditional ammunition has the guidance ability at a lower cost, and the ammunition striking precision is improved. The trajectory correction mechanism mainly comprises nine parts of a spin-reducing rudder blade, a direction rudder blade, a wind cap, a connecting shaft, an electromagnetic damping ring, a speed regulating electromagnet, a steering electromagnet and an angular contact bearing. The spin-reducing rudder blade and the direction rudder blade are fixed on the wind cap, the spinning speed and the phase are controlled by the magnetic moment generated by the electromagnetic damping ring and the speed regulating electromagnet and the rolling moment generated by the spin-reducing rudder blade, and the swinging direction and the frequency are controlled by the steering electromagnet fixed on the connecting shaft.

Description

Technical Field

[0001] This invention belongs to the field of aircraft technology, specifically relating to a two-dimensional ballistic correction mechanism based on electromagnetic damping. Background Technology

[0002] Among the many options for the guidance and upgrading of traditional ammunition, adding a ballistic correction device to the original ordinary shell to actively control the trajectory of the shell in flight can save a lot of research and development design and manufacturing costs, and at the same time help reduce inventory. Therefore, it is a promising low-cost ammunition guidance solution.

[0003] Currently, the control actuators of canard trajectory correction components offered by various countries are mainly of two types: fixed canards and movable canards. Fixed canards have fixed canard blade angles, primarily changing the direction of control force through roll around the projectile axis. Their correction capability is generally limited by the canard deflection angle. Movable canards, on the other hand, use servo motors to drive the blade deflection, allowing for changes in the deflection angle and providing relatively greater correction capability. However, the blade drive requires additional actuators, resulting in a complex structure. Furthermore, conventional high-speed spinning projectiles primarily rely on their own rotation to ensure flight stability. To achieve speed and phase control of the canard blades, conventional methods would require high-overload, high-speed stepper motors to compensate for the influence of the projectile's spin speed on the guidance components, along with control devices and power modules, resulting in significant weight and cost. Summary of the Invention

[0004] This invention proposes a two-dimensional ballistic correction mechanism based on electromagnetic damping. It achieves rudder phase control through electromagnetic damping and rudder deflection angle control using electromagnets, thus integrating fixed and movable canard rudders in a low-cost manner. Because it combines the characteristics of both canard rudders, it can adapt to a wider range of guidance laws, further broadening the applicable types of guidance improvements for conventional munitions. This is of great significance for improving the ability of conventional munitions to accurately strike high-value targets and enhancing the cost-effectiveness of combat operations.

[0005] The technical solution for achieving this invention is as follows: a two-dimensional ballistic correction mechanism based on electromagnetic damping, comprising a wind cap, a pendulum, a connecting shaft, a bearing sleeve, an electromagnetic damping ring, a speed regulating electromagnet, two anti-spin rudders, two directional rudders, a pair of steering electromagnets, and two angular contact bearings; the two anti-spin rudders and the two directional rudders are evenly and alternately arranged around the arc-shaped outer wall of the wind cap at equal intervals; the upper end of the central pendulum shaft is fixed to the center of the top surface of the inner wall of the wind cap; the central pendulum shaft is connected to the connecting shaft via a pin, allowing the wind cap to rotate with the connecting shaft, and the wind cap to swing around the pin; the phase control and deflection angle control of the rudders are achieved through the joint rotation and swing of the connecting shaft and the central pendulum shaft; the pendulum is located at the lower end of the central pendulum shaft; the pair of steering electromagnets, the electromagnetic damping ring, the two angular contact bearings, and the speed regulating electromagnet are all located inside the wind cap.

[0006] The connecting shaft is sequentially connected from top to bottom to a pair of brackets, a platform, and a fourth-order rotating shaft with decreasing diameter. The pair of brackets are symmetrically arranged, each with pin holes for connecting to the central pendulum shaft. A pair of directional electromagnets are asymmetrically mounted on the platform. In the initial position, the geometric center of the pendulum at the lower end of the central pendulum shaft coincides with the central axis of the connecting shaft and is attracted to one of the directional electromagnets. The pendulum swings without interfering with the top surface of the platform or the brackets. By changing the direction, magnitude, and frequency of the current in the directional electromagnets, the position of the pendulum is changed, thereby driving the wind cap to swing, ultimately changing... The rudder deflection angle of the rudder blades; the four-stage rotating shafts, from top to bottom, are the first stage shaft, the second stage shaft, the third stage shaft, and the fourth stage shaft. The second stage shaft is equipped with two angular contact bearings, and the inner ring of the bearings is interference-fitted with the second stage shaft. The third stage shaft is fixedly connected to a speed regulating electromagnet. The upper end of the electromagnetic damping ring is fixedly connected to the inner wall of the bearing sleeve, and the speed regulating electromagnet is located inside the electromagnetic damping ring. The spin speed and phase of the wind cap are jointly controlled by the magnetic torque generated by the electromagnetic damping ring and the speed regulating electromagnet, as well as the rolling torque generated by the anti-spin rudder blades, ultimately controlling the spin speed and position of the rudder blades and the anti-spin rudder blades.

[0007] Compared with the prior art, the significant advantages of this invention are:

[0008] (1) The electromagnetic damping ring is used to replace the traditional high-speed stepper motor, which makes the structure more compact, the drive simpler and more convenient, lighter and lower in cost.

[0009] (2) It combines the advantages of the strong maneuverability of movable canard rudders and the simple operation of fixed canard rudders, and can adapt to a wider range of guidance laws. It solves the problem of the full circumferential rotation of the normal control force required when the high-rotation projectile is flying at a lower cost, which is conducive to the attitude adjustment of the corrected projectile, improves the correction efficiency, and makes the projectile strike accuracy higher.

[0010] (3) The mechanism avoids the use of permanent magnet materials, which solves the problem of permanent magnets being demagnetized by impact and causing functional failure due to the high overload environment during the launch process. Attached Figure Description

[0011] Figure 1 The diagram shows the external structure of a wind cap for a two-dimensional ballistic correction mechanism based on electromagnetic damping, as proposed in the invention. (a) is the front view, and (b) is the top view of (a).

[0012] Figure 2 This is a schematic diagram of a two-dimensional ballistic correction mechanism based on electromagnetic damping proposed in the invention.

[0013] Figure 3 The diagram shows a speed-regulating electromagnet structure for a two-dimensional ballistic correction mechanism based on electromagnetic damping, as proposed in the invention. (a) is a top view, and (b) is a front view.

[0014] Figure 4 The diagram shows a connecting shaft structure of a two-dimensional ballistic correction mechanism based on electromagnetic damping proposed in the invention, wherein (a) is the front view, (b) is the side view, and (c) is a partial sectional view. Detailed Implementation

[0015] 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0017] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; "connection" can mean a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0018] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible to those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0019] The following section will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention, using this design example as an example.

[0020] Combination Figures 1-4To achieve the guided transformation of conventional munitions at low cost, this invention proposes a two-dimensional ballistic correction mechanism based on electromagnetic damping, comprising a wind cap 1, a pendulum 6, a connecting shaft 10, a bearing sleeve 11, an electromagnetic damping ring 12, a speed regulating electromagnet 13, two anti-spin rudders 2, two directional rudders 3, a pair of steering electromagnets 7, and two angular contact bearings 9. The two anti-spin rudders 2 and the two directional rudders 3 are evenly and alternately arranged around the arc-shaped outer wall of the wind cap 1 at equal intervals. The upper end of the central pendulum shaft 4 is fixed to the center of the top surface of the inner wall of the wind cap 1. The central pendulum shaft 4 is connected to the connecting shaft 10 through a pin 5, allowing the wind cap 1 to rotate with the connecting shaft 10 and swing around the pin 5. The pendulum 6 is located at the lower end of the central pendulum shaft 4.

[0021] To achieve the integration of fixed and movable canard rudders, this invention utilizes the combined rotation and oscillation of the connecting shaft 10 and the central pendulum shaft 4 to realize rudder phase control and rudder deflection angle control. Because the design uses a damping ring instead of a high-speed stepper motor resistant to high overload, the cost is significantly reduced, and the weight of the correction mechanism is minimized. The connecting shaft 10 is sequentially connected from top to bottom to a pair of supports, a platform, and a fourth-order shaft with decreasing diameter. The pair of supports are symmetrically arranged, each with pin holes for connecting the central pendulum shaft 4 via pins 5. A pair of steering electromagnets 7 are asymmetrically mounted on the platform. At the initial position, the geometric center of the pendulum 6 at the lower end of the central pendulum shaft 4 coincides with the central axis of the connecting shaft 10 and is attracted to one of the steering electromagnets 7. The pendulum 6 does not interfere with the top surface of the platform or the supports during its oscillation. By changing the direction, magnitude, and frequency of the current in the steering electromagnet 7, the position of the pendulum 6 is changed, thereby driving the wind cap 1 to swing, ultimately changing the deflection angle of the rudder 3. The four-stage rotating shafts are, from top to bottom, the first stage shaft, the second stage shaft, the third stage shaft, and the fourth stage shaft. The second stage shaft is equipped with two angular contact bearings 9, and the inner ring of the bearing is interference-fitted with the second stage shaft. The third stage shaft is fixedly connected to the speed regulating electromagnet 13. The upper end of the electromagnetic damping ring 12 is fixedly connected to the inner wall of the bearing sleeve 11, and the speed regulating electromagnet 13 is located inside the electromagnetic damping ring 12. The spin speed and position of the wind cap 1 are jointly controlled by the magnetic torque generated by the electromagnetic damping ring 12 and the speed regulating electromagnet 13, as well as the rolling torque generated by the anti-spin rudder 2, ultimately controlling the spin speed and phase of the rudder 3 and the anti-spin rudder 2.

[0022] Two anti-spin rudders 2 and two directional rudders 3 are symmetrically and alternately distributed in a "cross" shape on the outer arc of the wind cap 1. The anti-spin rudders 2 have an anti-symmetrical angle of attack, while the directional rudders 3 have a symmetrical angle of attack, or an angle of attack of zero. The central pendulum shaft 4 is fixed to the top surface of the inner wall of the wind cap 1 along the central axis of the wind cap 1. The lower end of the central pendulum shaft 4 is connected to a ferromagnetic pendulum 6, which, together with the steering electromagnet 7, controls the swing direction and frequency of the wind cap 1. The swing direction is consistent with the normal direction of the directional rudder surface of the rudder 3. The electromagnet is used as a power source to realize the control of the rudder deflection angle, replacing the drive mechanism of the traditional movable canard rudder.

[0023] To accommodate the handling needs of ammunition of various calibers, this invention proposes design parameters for the winding of the steering electromagnet 7. The core of the steering electromagnet 7 has a square cross-section. To ensure stable operation, the diameter d and length l of its winding coil conductors satisfy the following relationship:

[0024]

[0025]

[0026] In the formula, u is the operating voltage, which is generally taken as 3.7V to 12V for missile-borne systems; μ0 is the vacuum permeability, which can generally be taken as 4π×10⁻⁶. -5 Wb / A·m; ρ is the resistivity of the winding coil conductor, using enameled copper wire, with a value of 0.0172 Ω·mm. 2 / m;δ max The maximum air gap between the steering electromagnet 7 and the central pendulum 6; c is the side length of the square cross-section; K0 is the allowable magnetic force coefficient, which can generally be selected with reference to the empirical values ​​in Table 1; C d The drag coefficient of rudder piece 3, C h C is the lift coefficient of rudder piece 3. d and C h All are determined by the airfoil; β is the installation angle of the rudder blade 3; v is the velocity of the projectile; S F L represents the frontal area of ​​the rudder blade 3. co θ is the distance between the center of the pendulum and the center of pin 5; θ is the angle of attack of the rudder 3; θ0 is the angle of attack of the projectile; δ is the air gap between the steering electromagnet 7 and the central pendulum 6.

[0027] Considering both coil heating and lifespan, the winding coil wire length l of the steering electromagnet 7 should also meet the following requirements:

[0028]

[0029] Allowable current density E p In this invention, 9.97 A / mm can be used. 2 ~18.99A / mm 2 .

[0030] Table 1 Permissible Magnetic Force Coefficient

[0031] ammunition Coefficient range Mortar shells 2.1～4.7 Subsonic rockets 5.1～7.3 120mm mortar shell 8.1～9.6 155mm howitzer shells 9.6～12.3

[0032] The speed-regulating electromagnet 13 consists of a cross-shaped speed-regulating core 15 and four windings 8. The speed-regulating core 15 can be made of stacked silicon steel sheets, and the four windings 8 are installed at the outer ends of the cross-shaped core 15. A square hole is opened in the center of the speed-regulating core 15 for transition fit with the connecting shaft 10. A limiting shim 14 is provided in the speed-regulating electromagnet 13 to control its axial position. The limiting shim 14 can be riveted to the connecting shaft 10 to obtain greater connection strength and ensure stable connection of the speed-regulating electromagnet 13.

[0033] The upper end of the electromagnetic damping ring 12 is threadedly connected to the lower end of the bearing sleeve 11. The angular contact bearing 9 inside the bearing sleeve 11 achieves "rotation isolation" between the electromagnetic damping ring 12 and the connecting shaft 10, meaning that the speed regulating electromagnet 13 can rotate independently of the electromagnetic damping ring 12 around the axis of the connecting shaft 10. The lower inner ring of the electromagnetic damping ring 12 is fixed to the projectile and rotates with the projectile. By adjusting the current on the speed regulating electromagnet 13, magnetic fields of different intensities are generated, which interact with the electromagnetic damping ring 12 to produce a rotational damping torque. The rotational damping torque and the rolling torque of the anti-rotation rudder 2 work together to control the rotation angle of the anti-rotation rudder 2 and the directional rudder 3.

[0034] In summary, this invention proposes a two-dimensional ballistic correction mechanism based on electromagnetic damping, which can be used for ballistic correction of highly spin-stability munitions. The electromagnetic damping mechanism achieves phase control of the guidance group's control blades, while electromagnets control the control blade deflection angle, thus integrating fixed and movable canard control mechanisms at a low cost. Because it combines the characteristics of both types of canard control mechanisms, it can adapt to a wider range of guidance laws. This enables conventional munitions to possess guidance capabilities at a lower cost, improving munition accuracy.

Claims

1. A two-dimensional ballistic correction mechanism based on electromagnetic damping, characterized in that: The system includes a wind cap (1), a central pendulum shaft (4), a pendulum (6), a connecting shaft (10), an electromagnetic damping ring (12), a speed regulating electromagnet (13), two anti-spin rudders (2), two directional rudders (3), a pair of steering electromagnets (7), and two angular contact bearings (9). The two anti-spin rudders (2) and the two directional rudders (3) are evenly and alternately arranged in a ring around the outer arc of the wind cap (1). The upper end of the central pendulum shaft (4) is fixed to the center of the top surface of the inner wall of the wind cap (1). The central pendulum shaft (4) is connected to the wind cap (1). The pin (5) is connected to the connecting shaft (10), so that the wind cap (1) can rotate with the connecting shaft (10). At the same time, the wind cap (1) can also swing around the pin (5). The phase control of the rudder and the deflection angle of the rudder are realized by the joint rotation and swing of the connecting shaft (10) and the central pendulum shaft (4). The pendulum (6) is set at the lower end of the central pendulum shaft (4). A pair of steering electromagnets (7), electromagnetic damping rings (12), two angular contact bearings (9) and speed regulating electromagnets (13) are all set inside the wind cap (1). The two-dimensional ballistic correction mechanism based on electromagnetic damping also includes a bearing sleeve (11). The connecting shaft (10) includes, from top to bottom, a pair of supports, a platform, and a fourth-order shaft with decreasing diameter. The pair of supports are symmetrically arranged and each has a pin hole for connecting the central pendulum shaft (4) via a pin (5). A pair of steering electromagnets (7) are asymmetrically installed on the platform. At the initial position, the geometric center of the pendulum (6) at the lower end of the central pendulum shaft (4) coincides with the central axis of the connecting shaft (10) and is attracted to one of the steering electromagnets (7). When the pendulum (6) swings, it does not interfere with the top surface of the platform or the supports. By changing the current direction, magnitude, and frequency of the steering electromagnet (7), the position of the pendulum (6) is changed, thereby driving the wind. The cap (1) swings, ultimately changing the deflection angle of the rudder (3); the four-stage rotating shafts are, from top to bottom, the first stage shaft, the second stage shaft, the third stage shaft, and the fourth stage shaft. The second stage shaft is equipped with two angular contact bearings (9), and the inner ring of the bearing is interference-fitted with the second stage shaft. The third stage shaft is fixedly connected to a speed regulating electromagnet (13). The upper end of the electromagnetic damping ring (12) is fixedly connected to the inner wall of the bearing sleeve (11), and the speed regulating electromagnet (13) is located inside the electromagnetic damping ring (12). The spin speed and phase of the wind cap (1) are jointly controlled by the magnetic torque generated by the electromagnetic damping ring (12) and the speed regulating electromagnet (13) and the rolling torque generated by the anti-spin rudder (2), ultimately controlling the spin speed and position of the rudder (3) and the anti-spin rudder (2).

2. The two-dimensional ballistic correction mechanism based on electromagnetic damping according to claim 1, characterized in that: The upper end of the electromagnetic damping ring (12) is connected to the lower end of the bearing sleeve (11) by a thread. The electromagnetic damping ring (12) and the connecting shaft (10) are "isolated" by the angular contact bearing (9) in the bearing sleeve (11), that is, the speed regulating electromagnet (13) and the electromagnetic damping ring (12) rotate independently around the axis of the connecting shaft (10). The lower inner ring of the electromagnetic damping ring (12) is fixed to the projectile and rotates with the projectile. By adjusting the current on the speed regulating electromagnet (13), a magnetic field of different intensities is generated and interacts with the electromagnetic damping ring (12) to generate a rotational damping torque. The rotational damping torque and the rolling torque of the anti-rotation rudder (2) work together to achieve the rotation angle control of the anti-rotation rudder (2) and the directional rudder (3).

3. The two-dimensional ballistic correction mechanism based on electromagnetic damping according to claim 2, characterized in that: The central pendulum shaft (4) is fixed to the top surface of the inner wall of the wind cap (1) along the central axis of the wind cap (1). The lower end of the central pendulum shaft (4) is connected to the ferromagnetic pendulum (6), which, together with the steering electromagnet (7), controls the swing direction and frequency of the wind cap (1). The swing direction is consistent with the normal direction of the rudder surface of the rudder blade (3). The electromagnet is used as a power source to realize the control of the rudder blade deflection angle, replacing the traditional movable canard rudder drive mechanism.

4. The two-dimensional ballistic correction mechanism based on electromagnetic damping according to claim 3, characterized in that, To accommodate ammunition of more calibers, the winding parameters of the steering electromagnet (7) need to be designed, as follows: Assuming the cross-section of the core of the steering electromagnet (7) is square, to ensure stable operation, the diameter d and length l of its winding coil wire must satisfy the following relationship: In the formula, u is the operating voltage, which is taken as 3.7V to 12V for missile-borne systems; μ0 is the vacuum permeability, taken as 4π×10⁻⁶. -5 Wb / A·m; ρ is the resistivity of the winding coil conductor, using enameled copper wire, with a value of 0.0172 Ω·mm. 2 / m;δ max The maximum air gap between the steering electromagnet (7) and the central pendulum (6); c is the side length of the square cross-section; K0 is the allowable magnetic force coefficient; C d The drag coefficient of the rudder blade (3), C h β is the lift coefficient of the rudder (3); β is the installation angle of the rudder (3); v is the velocity of the projectile; S F L is the frontal area of ​​the rudder blade (3); co θ is the distance between the center of the pendulum and the center of the pin (5); θ is the angle of attack of the rudder (3), θ0 is the angle of attack of the projectile, and δ is the air gap between the steering electromagnet (7) and the central pendulum (6); Considering both coil heating and lifespan, the winding coil wire length l of the steering electromagnet (7) should also satisfy: Allowable current density E p Take 9.97A / mm 2 ~18.99A / mm 2 .

5. The two-dimensional ballistic correction mechanism based on electromagnetic damping according to claim 4, characterized in that, The allowable magnetic flux density K0 satisfies the following table: Table 1 Permissible magnetic force coefficient K0 。 6. The two-dimensional ballistic correction mechanism based on electromagnetic damping according to claim 1, characterized in that: Two anti-spin rudders (2) and two directional rudders (3) are symmetrically and alternately distributed in a "cross" shape on the outer arc of the wind cap (1). The anti-spin rudder (2) has an anti-symmetrical angle of attack, while the directional rudder (3) has a symmetrical angle of attack, or it can have a zero angle of attack.

7. The two-dimensional ballistic correction mechanism based on electromagnetic damping according to claim 1, characterized in that: The speed-regulating electromagnet (13) consists of a "cross"-shaped speed-regulating iron core (15) and four windings (8). The speed-regulating iron core (15) is made of stacked silicon steel sheets, and the four windings (8) are installed at the outer end of the "cross" of the speed-regulating iron core (15). The speed-regulating iron core (15) has a square hole in the center for transitional fit with the connecting shaft (10).

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