Gun muzzle eddy current damping shock absorber suitable for tank gun

Abstract

A front platform comprises a magnetic conductive outer ring, a front-end fastener and a conductor inner ring, the conductor inner ring is connected with the magnetic conductive outer ring, the magnetic conductive outer ring is connected with the front-end fastener, and the front-end fastener is fixed to the outer wall of a barrel; the rear platform comprises a fixator and a flexible rod, and the fixator is fixed to the outer wall of the barrel; the moving platform comprises a permanent magnet and a base, the permanent magnet is connected with the base, the base is connected with the flexible rod, and the moving platform can move relative to the front platform and the rear platform; the permanent magnet adopts a Halbach array magnetic circuit structure, the magnetization direction of each permanent magnet unit is sequentially rotated by 90 degrees along the radial direction, and the permanent magnet units, the conductor inner ring and the magnetic conductive outer ring jointly form a complete two-dimensional axisymmetric magnetic circuit structure. Vibration kinetic energy is converted into heat energy to be dissipated through a non-contact eddy current damping mechanism, and the device has the advantages of high reliability, light weight and environmental adaptability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of muzzle vibration reduction, and particularly relates to a muzzle eddy current damper for a tank gun. BACKGROUND

[0002] In view of the problem of high-frequency vibration suppression of the tank barrel under the shooting conditions of high-speed maneuvering and marching, the traditional active control system is limited by the bandwidth characteristics and the forced locking mechanism at the moment of launching, and it is difficult to effectively suppress the high-order modal vibration of the ultra-long-diameter barrel. This technical bottleneck makes the initial attitude regulation at the moment of projectile ejection have essential defects, and it is urgent to develop high-frequency passive vibration suppression technology with environmental adaptability and passive reliability. In the current passive vibration suppression field, the tuned mass damper (TMD) has verified its effectiveness in low-frequency vibration control of buildings, bridges and other structures through the resonance energy absorption mechanism of the mass-spring-damper unit. However, for military equipment such as tank barrels, which have high frequency, high stiffness and strong transient impact characteristics, the traditional TMD faces the following challenges: first, the high-frequency resonance requirement leads to a sharp increase in the volume and weight of the mass, which contradicts the lightweight and spatial layout of the tank barrel; second, the invasion of sand in harsh battlefield environments easily causes the jamming failure of mechanical TMD. Therefore, a new type of eddy current TMD based on multidisciplinary cross has become a breakthrough direction. This structure converts the barrel vibration energy into eddy current heat energy dissipation through magnetic circuit coupling design. It does not need to adjust the counterweight, but only needs to adjust the gap and other parameters to achieve damping change, which meets the lightweight requirement. The non-contact working characteristic fundamentally avoids the problem of mechanical wear and tear. SUMMARY

[0003] The present application aims to provide a muzzle eddy current damper for a tank gun, which suppresses the high-order modal vibration of the tank barrel during shooting in maneuvering and marching by reducing the structural mass and optimizing the structural performance, realizes passive and reliable vibration energy efficient dissipation with strong environmental adaptability, overcomes the defects of traditional mechanical TMD in high-frequency adaptability, lightweight and anti-sand jamming, and thus improves the initial attitude accuracy of the projectile ejection.

[0004] The technical solution for achieving the purpose of the present application is as follows: a muzzle eddy current damper for a tank gun, comprising a front platform, a moving platform and a rear platform, the front platform comprising a magnetically conductive outer ring (1), a front end fastener (3) and a conductor inner ring (6), the conductor inner ring (6) being connected with the magnetically conductive outer ring (1), the magnetically conductive outer ring (1) being connected with the front end fastener (3), and the front end fastener (3) being fixed with the barrel outer wall; the rear platform comprising a fixator (12) and a flexible rod (13), the fixator (12) being fixed with the barrel outer wall; the moving platform comprising a permanent magnet (7) and a base (8), the permanent magnet (7) being connected with the base (8), and the base (8) being connected with the flexible rod (13), the moving platform being capable of relative movement with respect to the front platform and the rear platform.

[0005] The magnetic conductive outer ring (1), the front end fastener (3), the conductor inner ring (6), the permanent magnet (7), the base (8) and the fixer (12) are coaxial rotationally symmetrical designs, are centrally perforated and are sleeved on the barrel, the permanent magnet (7) and the base (8) have a hole diameter slightly larger than the outer diameter of the barrel, the central circular hole diameters of the magnetic conductive outer ring (1), the front end fastener (3), the conductor inner ring (6) and the fixer (12) are equivalent to the outer diameter of the barrel; the permanent magnet (7) adopts a Halbach array magnetic circuit structure, the magnetization directions of each permanent magnet unit are sequentially rotated by 90° along the radial direction, and the permanent magnet (7) and the conductor inner ring (6) and the magnetic conductive outer ring (1) together form a complete two-dimensional axisymmetric magnetic circuit structure, the strong magnetic induction lines generated by the Halbach array arranged permanent magnet (7) pass through the working air gap into the conductor inner ring (6), and after forming a loop through the magnetic conductive outer ring (1), the strong magnetic induction lines return to the permanent magnet (7) through the air gap again, thereby constituting a complete magnetic flux path.

[0006] Further, the front platform comprises a magnetic conductive outer ring (1), a first screw (2), a front end fastener (3), a first gasket (4), a third screw (5) and a conductor inner ring (6), the conductor inner ring (6) and the magnetic conductive outer ring (1) are homogeneous solid circular rings, the thicknesses are h ct and h bi respectively, the outer circle radii are r ct and r bi respectively, and the two are connected by a magnetic adhesive; the outer surface of the magnetic conductive outer ring (1) has four rotationally symmetrical threaded blind holes, the front end fastener (3) is a hollow cylindrical structure, and four threaded through holes exist at the positions corresponding to the contact surface of the magnetic conductive outer ring (1), the magnetic conductive outer ring (1) is fixed with the front end fastener (3) through the first screw (2); the front end fastener (3) is provided with four rotationally symmetrical threaded through holes on the side surface, is sleeved on the outside of the barrel, and is fastened with the outer wall of the barrel through the third screw (5), and the first gasket (4) is sleeved on the rod part of the first screw (2).

[0007] Further, the magnetic conductive outer ring (1) selects an iron-silicon-aluminum magnetic powder core as a material, the material has lower density, high electrical conductivity and moderate mechanical strength compared with traditional silicon steel materials, can effectively resist the instantaneous impact load of the barrel and can greatly reduce the eddy current loss; the front end fastener (3) selects carbon fiber as a material, so that the damper does not adversely affect the original function of the barrel; and the conductor inner ring (6) selects copper as a material.

[0008] Further, in the motion platform, the permanent magnet (7) is a ring-shaped permanent magnet array, the pole distance of the permanent magnet unit is τ, the radial thickness of the permanent magnet unit is b, and the axial thickness is h m, and fixed on the base (8) by magnetic adhesive; the base (8) has four rotationally symmetrical threaded guide holes on the rear end surface, and is connected to the fixator (12) of the rear platform through the flexible rods (13).

[0009] Further, the permanent magnet (7) adopts a circular ring design, and the magnetization directions of the permanent magnet units in the permanent magnet array are alternately arranged along the radial direction of the permanent magnet (7) according to the Halbach array rule, forming a strong magnetic field region above the upper end surface of the permanent magnet (7) and parallel to the lower surface of the inner conductor ring (6), which effectively controls the total mass of the device and significantly shortens the axial dimension, thereby better meeting the installation requirements of the artillery system.

[0010] Further, the permanent magnet (7) uses N52 sintered neodymium iron boron as the material, which has excellent magnetic properties, good economy and high processability; the base (8) uses carbon fiber material.

[0011] Further, the rear platform includes a second screw (9), a nut (10), a second gasket (11), a fixator (12) and a flexible rod (13), the fixator (12) has four rotationally symmetrical through holes on the front end surface at the same positions as the threaded guide holes on the rear end surface of the base (8), the flexible rod (13) is a homogeneous low-rigidity solid long rod with a length of L, the front end is inserted into the guide hole of the base (8), and the rear end is connected to the through hole of the fixator (12), the fixation with the fixator (12) and the base (8) is realized through three groups of nuts (10), and the second gasket (11) is arranged at the connection; the fixator (12) has a hollow cylindrical structure, four rotationally symmetrical threaded holes are arranged on the side surface, is sleeved on the outer part of the barrel, and is fastened with the outer wall of the barrel through the second screw (9).

[0012] Further, the fixator (12) is made of carbon fiber material, when the natural frequency of the flexible rod (13) and the barrel is close, the relative speed of the permanent magnet (7) and the inner conductor ring (6) is maximum, and therefore 6061-T6 aluminum alloy is used as the material.

[0013] Further, the strong magnetic induction lines generated by the Halbach array arranged permanent magnet (7) pass through the working air gap into the inner conductor ring (6), form a loop through the magnetic conductive outer ring (1), and then pass through the air gap to return to the permanent magnet (7) again, to form a complete magnetic path; the magnetic path includes the following elements: R bi is the magnetic resistance of the magnetic path in the outer ring; R gm is the magnetic resistance of the main magnetic path passing through the inner conductor ring; R l is the magnetic resistance of the leakage magnetic path in the air gap, which is derived from the average length and average volume of the leakage magnetic path; R pm,i is the magnetic resistance of each permanent magnet unit; F pm is the magnetic motive force of the permanent magnet.

[0014] Five key parameters of the eddy current damper are selected as design optimization variables: air gap thickness g, conductor inner ring thickness h ct , thickness of magnetic outer ring h bi , the axial thickness of the permanent magnet h m , the circumferential arrangement angle interval of the permanent magnet is θ, and according to the magnetic circuit structure analysis, the eddy current resistance F is further calculated. MEC On the basis of the magnetic circuit structure, the optimal solution of key parameters is obtained by constructing a proxy prediction model of the muzzle eddy current damper based on the BP neural network. The basic steps are as follows:

[0015] (1) Derivation of eddy current resistance F based on the magnetic circuit structure of eddy current damping shock absorber MEC , to maximize the eddy current resistance F MEC As the objective function, the optimization problem model is constructed with the upper and lower limits of key parameters under the conditions of ensuring magnetic field gain and structural reliability as constraints:

[0016]

[0017] Where f(X) is F MEC The corresponding objective function is and are the upper and lower limits of the values ​​of each design variable to be optimized;

[0018] (2) Latin hypercube sampling (LHS) is used to obtain the sample library;

[0019] (3) Create a BP neural network;

[0020] (4) Using the square error R 2 Test the accuracy of training results;

[0021] (5) Genetic algorithm is used to perform global optimization solution on the agent model.

[0022] Furthermore, when the gun barrel vibrates, the front end fastener (3) and the holder (12) are both sleeved and fixed on the outer wall of the barrel, and are relatively stationary with the gun barrel, while the base (8) generates relative motion with the barrel due to the presence of the flexible rod (13). At this time, the strong magnetic flux lines generated by the permanent magnet (7) installed on the base (8) cut the inner ring (6) of the conductor, and an eddy current field is excited inside the inner ring (6); according to the principle of electromagnetic induction, these eddy currents will generate an induced magnetic field in the opposite direction to the original magnetic field, and the interaction of the two magnetic fields will form an eddy current damping force in the opposite direction to the relative motion trend, that is, an eddy current damping effect that hinders the relative displacement of the moving parts is generated. The direction of this damping force is always opposite to the direction of motion, thereby hindering the vibration of the barrel and achieving effective dissipation of vibration energy.

[0023] Compared with the prior art, the present application has the following advantages:

[0024] (1) The present application introduces electromagnetic damping technology into the field of barrel vibration control of high-mobility assault weapons, and generates relative motion through barrel vibration, relative motion of the permanent magnet and the inner conductor ring, and magnetic field generated by the inner conductor ring cutting the permanent magnet, thereby generating eddy current damping force, which is related to the speed of motion, so that it can adapt to the vibration characteristics in different combat environments, the working process has no mechanical wear, avoids the problems of easy failure and limited service life of traditional mechanical dampers, and realizes effective dissipation of vibration energy and effective suppression of barrel vibration;

[0025] (2) The present application adopts coaxial rotational symmetry design of the front platform, the motion platform and the rear platform, and has a two-dimensional axisymmetric magnetic circuit structure, and a through hole is arranged in the center, which can be directly sleeved on the outer wall of the barrel and fixed through fasteners, thereby significantly reducing the difficulty of installation and disassembly, ensuring the compactness of the structure and the reliability of the installation, and reducing the influence on the original function of the gun;

[0026] (3) The present application adopts an improved annular Halbach array magnetic circuit structure, forms a high-strength and concentrated magnetic field distribution, effectively improves the eddy current damping effect, improves the utilization efficiency of the permanent magnet, avoids energy dissipation, significantly shortens the axial size and reduces the total mass, and better meets the limited installation space and weight reduction requirements of the gun system;

[0027] (4) The present application performs multi-objective optimization design on the key structural parameters of the eddy current damper through the agent prediction model based on the BP neural network, can maximize the damping performance under the premise that the quality and size are limited within a certain range, and improves the designability and adaptability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a whole structure diagram of a barrel eddy current damping vibration damper suitable for a tank gun of the present application.

[0029] Figure 2 It is an axonometric view of the present application.

[0030] Figure 3 It is a magnetic circuit structure based on the Halbach array of the present application.

[0031] Figure 4 It is an MEC model of the present application.

[0032] Figure 5 It is an optimization process block diagram of parameter design of the present application.

[0033] Figure 6 It is a regression diagram of the training results of the BP neural network.

[0034] Figure 7 Figure is the optimization iteration process diagram of genetic algorithm.

[0035] Figure 8 Figure is the input torque curve.

[0036] Figure 9 Figure is the muzzle height angle displacement contrast curve.

[0037] Figure 10 Figure is the muzzle height line displacement contrast curve.

[0038] In the figure: 1 is a magnetic outer ring, 2 is a first screw, 3 is a front end fastener, 4 is a first gasket, 5 is a third screw, 6 is a conductor inner ring, 7 is a permanent magnet, 8 is a base, 9 is a second screw, 10 is a nut, 11 is a second gasket, 12 is a fixator, and 13 is a flexible rod. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0040] The present application provides a muzzle eddy current damping vibration damper suitable for a tank gun, which relates to the field of muzzle damping and is used to solve the problem of high-frequency vibration suppression of a tank barrel during high-speed maneuvering and shooting in a traveling condition.

[0041] As shown in Figure 1 The present application provides a muzzle eddy current damping vibration damper suitable for a tank gun, which relates to the field of muzzle damping and is used to solve the problem of high-frequency vibration suppression of a tank barrel during high-speed maneuvering and shooting in a traveling condition.

[0042] The front platform comprises a magnetic outer ring 1, a front end fastener 3 and a conductor inner ring 6, the conductor inner ring 6 is connected with the magnetic outer ring 1, the magnetic outer ring 1 is connected with the front end fastener 3, and the front end fastener 3 is fixed with the barrel outer wall; the moving platform comprises a permanent magnet 7 and a base 8, the permanent magnet 7 is connected with the base 8, the base 8 is connected with a flexible rod 13, and the moving platform can move relatively to the front platform and the rear platform; the rear platform comprises a fixator 12 and the flexible rod 13, the flexible rod 13 is connected with the fixator 12, and the fixator 12 is fixed with the barrel outer wall.

[0043] The magnetic outer ring 1, the front end fastener 3, the conductor inner ring 6, the permanent magnet 7, the base 8 and the fixator 12 are coaxially rotationally symmetrical, are centrally perforated and are sleeved on the barrel, the permanent magnet 7 and the base 8 have a hole diameter slightly larger than the outer diameter of the tank gun barrel, and the magnetic outer ring 1, the front end fastener 3, the conductor inner ring 6 and the fixator 12 have a central hole diameter corresponding to the outer diameter of the barrel.

[0044] Further, the front platform is composed of a magnetic conductive outer ring 1, a first screw 2, a front end fastener 3, a first gasket 4, a third screw 5 and a conductor inner ring 6. The conductor inner ring 6 and the magnetic conductive outer ring 1 are homogeneous solid annular rings, with thicknesses of h ct and h bi , and outer circle radii of r ct and r bi , and are connected by a magnetic adhesive; the outer surface of the magnetic conductive outer ring 1 has four rotationally symmetric threaded blind holes, the front end fastener 3 is a hollow cylindrical structure, and four threaded through holes exist at the corresponding positions of the contact surface of the front end fastener 3 and the magnetic conductive outer ring 1, and the magnetic conductive outer ring 1 is fixed with the front end fastener 3 by the first screw 2; the side surface of the front end fastener 3 is provided with four rotationally symmetric threaded through holes, is sleeved on the outside of the body tube, and is fastened with the outer wall of the body tube by the third screw 5, and the first gasket 4 is sleeved on the rod part of the first screw 2.

[0045] The motion platform is composed of a permanent magnet 7 and a base 8. The permanent magnet 7 is an annularly arranged permanent magnet array, with a pole distance of τ, a radial thickness of b, and an axial thickness of h m , and is fixed on the base 8 by a magnetic adhesive; the outer side of the rear end surface of the base 8 has four rotationally symmetric threaded guide holes, which are connected with the fixator 12 of the rear platform by the flexible rod 13.

[0046] The rear platform is composed of a second screw 9, a nut 10, a second gasket 11, a fixator 12 and a flexible rod 13. The front end surface of the fixator 12 is provided with four rotationally symmetric through holes at the same positions as the threaded guide holes of the rear end surface of the base 8, the flexible rod 13 is four homogeneous low-rigidity solid long rods, with a length of L, the front end is inserted into the guide hole of the base 8, the rear end is connected with the through hole of the fixator 12, the fixation with the fixator 12 and the base 8 is realized by three groups of nuts 10, and the second gasket 11 is arranged at the connection; the fixator 12 is a hollow cylindrical structure, and the side surface has four rotationally symmetric threaded holes, is sleeved on the outside of the body tube, and is fastened with the outer wall of the body tube by the second screw 9.

[0047] In the assembly process, first, the magnetic adhesive is used to connect the magnetic outer ring 1 and the conductor inner ring 6, then the first screw 2 and the first gasket 4 are used to connect the front end fastener 3 and the magnetic outer ring 1, then the magnetic adhesive is used to connect the permanent magnet 7 and the base 8, the rear end of the flexible rod 13 is inserted into the surface through hole of the fixator 12, then the front end of the flexible rod 13 is inserted into the rear surface guide hole of the base 8, the nut 10 and the second gasket 11 are used to fix the four flexible rods 13 with the fixator 12 and the base 8 respectively, the magnetic outer ring 1, the front end fastener 3, the conductor inner ring 6, the permanent magnet 7, the base 8 and the fixator 12 are axially sleeved on the outer wall of the barrel, the position is adjusted so that the front end fastener 3 is located near the front end of the barrel, the flexible rod 13 is completely straightened and the distance between the front surface of the permanent magnet 7 and the rear surface of the conductor inner ring 6 is g, finally the third screw 5 and the second screw 9 are used to connect and fasten the front end fastener 3 and the fixator 12 with the outer wall of the barrel respectively.

[0048] The magnetic outer ring 1 selects the iron-silicon-aluminum magnetic powder core as the material, the front end fastener 3, the base 8 and the fixator 12 select the carbon fiber as the material, the conductor inner ring 6 selects the copper as the material, the permanent magnet 7 adopts the N52 sintered neodymium-iron-boron as the material, the flexible rod 13 adopts the 6061-T6 aluminum alloy as the material, and the remaining parts are standard parts.

[0049] Figure 2 It is the axonometric view of the application. Figure 2 When the barrel vibrates, the front end fastener 3 and the fixator 12 are sleeved and fixed on the outer wall of the barrel and are relatively stationary with the barrel, and the base 8 relatively moves with the barrel due to the existence of the flexible rod 13, at this time the strong magnetic induction lines generated by the permanent magnet 7 installed on the base 8 cut the conductor inner ring 6, and the inside of the conductor inner ring 6 will excite the eddy current field. According to the principle of electromagnetic induction, these eddy currents will generate an induced magnetic field opposite to the direction of the original magnetic field. The interaction of the two magnetic fields will form an electric eddy current damping force opposite to the relative motion trend, that is, an electric eddy current damping effect that hinders the relative displacement of the moving parts. The direction of this damping force is always opposite to the motion direction, thereby hindering the barrel vibration and realizing the effective dissipation of vibration energy.

[0050] Figure 3 It is the magnetic circuit structure diagram of the application based on the Halbach array, the magnetization directions of each permanent magnet unit are rotated by 90° in turn along the radial direction, and Figure 3 The two-dimensional axisymmetric magnetic circuit structure of the electric eddy current damping shock absorber can be divided into two parts of a stator and a rotor. The stator is the magnetic outer ring 1 and the conductor inner ring 6, and the rotor is composed of the flexible rod 13, the permanent magnet 7 and the base 8, and is connected with the rear platform fixator 12. In the figure, τ is the pole pitch, b is the radial thickness of the permanent magnet, h m is the axial thickness of the permanent magnet, h bi is the thickness of the outer ring, h ctis the inner ring thickness, g is the air gap thickness, r1 is the inner radius of the permanent magnet, r pm is the outer radius of the permanent magnet, r bi is the outer radius of the outer ring, r ct is the outer radius of the inner ring. Each component adopts a coaxial rotational symmetry design, the permanent magnet 7 adopts an improved Halbach array magnetic circuit structure, the traditional cylindrical structure is optimized to a ring design, the magnetization direction of the permanent magnet units in the permanent magnet array is alternately arranged along the radial direction of the permanent magnet 7 according to the Halbach array rule, and a strong magnetic field region parallel to the lower surface of the conductor inner ring (6) is formed above the upper end surface of the permanent magnet 7.

[0051] Next, the performance of the muzzle eddy current damper is analyzed.

[0052] Figure 4 is the MEC model of the application. In combination Figure 4 , the magnetic circuit structure is analyzed and the static air gap magnetic flux density B gs is derived before the establishment of the agent model. Due to the axial symmetry of the structure, it can be simplified as a two-dimensional axial symmetry problem. The permanent magnet 7, the air gap, the conductor inner ring 6 and the magnetic conductive outer ring 1 constitute the main magnetic flux path. As Figure 4 shown, an effective magnetic circuit model of an effective magnetic flux loop includes the following elements: R bi is the magnetic resistance of the magnetic flux path in the outer ring; R gm is the magnetic resistance of the main magnetic flux path through the conductor inner ring; R l is the magnetic resistance of the leakage magnetic flux path in the air gap, which is derived from the average length and average volume of the leakage magnetic flux path; R pm,i is the magnetic resistance of each permanent magnet; F pm is the magnetomotive force of the permanent magnet.

[0053] The detailed calculation formula of each lumped parameter in the equivalent magnetic circuit model of the permanent magnet type eddy current damper is given as follows:

[0054]

[0055] In the formula, S bi is the average area of the outer ring magnetic flux path; L l is the effective length of the air gap leakage magnetic path; V l is the volume of the air gap leakage magnetic path, and the calculation formula is V l =S l g (S l is the area of the air gap leakage magnetic path); μ0 is the vacuum permeability; μ r is the relative permeability; B r is the residual magnetic flux density of the permanent magnet.

[0056] Because of the asymmetry of the three effective flux loops, the calculation formulae of the magnetic reluctance R pmi (i = 1-7), the average area S bi (i = 1-4) of the outer ring flux path and the area S l of the air gap leakage flux path are not exactly the same, and the following expressions can be given:

[0057]

[0058]

[0059] where θ is the angle of the circumferential arrangement of the group of permanent magnets.

[0060] For the analysis of the nonlinear MEC model, a matrix system based on the network analysis formula algorithm can be established, as follows:

[0061]

[0062] where R 11 is equal to R pm1 + R pm2 + R pm3 + R l1 ; R 12 is equal to R l1 + R bi1 + 4R gm ; R 21 is equal to R pm3 + R pm4 + R pm5 + R l2 ; R 22 is equal to R l2 + R bi2 + 4R gm ; R 31 is equal to R pm5 + R pm6 + R pm7 + R l3 ; R 32 is equal to R l3 + R bi3 + 4R gm .

[0063] After obtaining the convergent solution, the static air gap flux density B gs can be calculated:

[0064]

[0065] Φ em = Φ2

[0066] S e = π(2h m + 2g + hct )b

[0067] Where, Φ em and S e are the magnetic flux and cross-sectional area of ​​the main flux path of the air gap, respectively.

[0068] J av =σ ct B gs v

[0069] Where, σ ct is the inner ring conductivity, and v is the relative velocity vector between the stator and the mover.

[0070] Eddy current resistance F calculated by MEC model MEC The expression is as follows:

[0071] F MEC =∫ V |J av ×B gs |dV

[0072] Where V is the volume of the inner ring.

[0073] The above eddy current resistance F MEC It is the key indicator to measure the performance of eddy current vibration damper.

[0074] Furthermore, the relevant design parameters of the present invention are determined according to the performance indicators, and a proxy prediction model of the muzzle eddy current vibration damper is constructed based on the BP neural network. The genetic algorithm is used to implement the optimization solution based on the proxy model to obtain the optimal solution of the relevant parameters.

[0075] Based on the analysis of the magnetic circuit characteristics of the muzzle eddy current damper, it can be seen that:

[0076] (1) The air gap thickness directly affects the magnetic resistance of the magnetic circuit. A smaller air gap can reduce the magnetic resistance and increase the air gap magnetic flux density, thereby enhancing the eddy current damping force. However, if the air gap is too small, it will cause the risk of mechanical interference. A balance needs to be struck between the magnetic field gain and the structural reliability.

[0077] (2) The thickness of the inner ring of the conductor determines the cross-sectional area of ​​the main magnetic flux path of the air gap, which directly affects the magnetic flux density of the air gap;

[0078] (3) The magnetic outer ring affects the efficiency of magnetic circuit closure. Too thin a ring can easily lead to magnetic saturation (B>B s When the magnetic conductivity drops sharply), if it is too thick, the weight will increase, and it is necessary to match the magnetic flux of the permanent magnet;

[0079] (4) The axial thickness of the permanent magnet directly determines the magnetomotive force (F pm =H c ·h m , H cTo increase the axial thickness of the permanent magnet can improve the air gap flux density, but will significantly increase the system volume, and B g is maximized while h m is minimized.

[0080] (5) The circumferential arrangement angle of the permanent magnet determines the magnetic field concentration characteristics of the Halbach array, and optimizing the circumferential arrangement angle can adjust the uniformity of the magnetic field distribution and avoid local eddy current saturation.

[0081] Therefore, five key parameters of the electric eddy current damper are selected as design optimization variables, namely: air gap thickness g, conductor inner ring thickness h ct , magnetic conductive outer ring thickness h bi , permanent magnet axial thickness h m , and permanent magnet circumferential arrangement angle interval θ. These five parameters are the core control variables of the magnetic field- eddy current-mechanical coupling system, directly affecting the damping force, volume and reliability. By optimizing them, the magnetic field strength can be maximized, the eddy current loss efficiency can be optimized, and the system can be lightweight, thereby meeting the high-efficiency damping requirements of the gun under instantaneous impact.

[0082] The target problem is described as:

[0083]

[0084] In the formula, f(X) is the F MEC corresponding objective function, and are the upper and lower limits of the values of each design variable to be optimized.

[0085] Figure 5 The optimization process diagram of the parameter design of the application is shown in the figure. In combination with Figure 5 , the application adopts a proxy prediction model of the muzzle electric eddy current damper based on a BP neural network, and relies on the proxy model to implement optimization and solution by using a genetic algorithm. The basic process is as follows:

[0086] (1) The optimization objective function, i.e., the electric eddy current resistance F MEC , is derived according to the magnetic circuit structure of the electric eddy current damper;

[0087] (2) Five key parameters of the electric eddy current damper are selected as design optimization variables, namely: air gap thickness g, conductor inner ring thickness h ct , magnetic conductive outer ring thickness h bi , permanent magnet axial thickness h m , and permanent magnet circumferential arrangement angle interval θ;

[0088] (3) The constraint conditions are established and the optimization problem model is constructed;

[0089] (4) Latin hypercube sampling (LHS) is adopted to obtain 110 groups of samples, 100 groups of which are used to train the BP neural network, and the other 10 groups are used to test the accuracy of the BP neural network;

[0090] (5) The BP neural network is created: the double hidden layers are set, the maximum training iteration is 1000, the training target error is 1x10-7, the data are randomly divided, and the Levenberg-Marquardt algorithm is adopted;

[0091] (6) The error square R 2 is used to test the accuracy of the training result, and the expression of R 2 is as follows:

[0092]

[0093] In the formula, n s is the sample number of the verification group; y i is the true value of the sample point response function of the verification group; is the predicted value of the BP neural network; is the mean value of the sample point response function of the verification group. The value of R 2 is between 0 and 1, and the closer the value is to 1, the higher the prediction accuracy of the BP neural network proxy model is.

[0094] (7) After the parameter optimization model and the proxy model are constructed, the genetic algorithm is adopted to globally optimize and solve the proxy model. The key parameters are set as follows: the initial population contains 500 individuals, the execution probability of the crossover operation is 95%, the adaptive mutation strategy is adopted and the mutation probability is controlled at the level of 35%, and the convergence criterion is set as the change amount of the fitness function value being less than 1x10 -7 . This combination of parameters effectively balances the development and exploration ability of the algorithm, and significantly reduces the risk of falling into a local optimal solution. The genetic algorithm is adopted to globally optimize and solve the proxy model.

[0095] Embodiment

[0096] In order to verify the creativity of the scheme of the application, the following design is performed.

[0097] The following table is the size parameter of the magnetic circuit structure.

[0098] Table 1 Size parameter of magnetic circuit structure

[0099]

[0100] The value range of the to-be-optimized variables of the eddy current damper is shown in the following table:

[0101] Table 2 Value range of to-be-optimized variables of eddy current damper

[0102]

[0103] The BP neural network agent model is established, the double hidden layer is set, the maximum training iteration is 1000, the training target error is 1x10 -7 , the data is randomly divided, and the Levenberg-Marquardt algorithm is adopted.

[0104] Figure 6 The regression graph of the BP neural network training result is shown in FIG. 6. Figure 6 The calculation results of all R 2 are greater than 0.98, which indicates that the established BP neural network agent model of the muzzle eddy current damper has good prediction accuracy.

[0105] After completing the parameter optimization model and the agent model construction, the genetic algorithm is adopted to globally optimize and solve the agent model. The key parameters are set as follows: the initial population contains 500 individuals, the crossover operation execution probability is 95%, the adaptive mutation strategy is adopted and the mutation probability is controlled at a level of 35%, and the convergence criterion is set as the fitness function value change amount being less than 1x10 -7 . This parameter combination effectively balances the development and exploration ability of the algorithm, and significantly reduces the risk of falling into a local optimal solution.

[0106] Figure 7 The optimization iteration process graph of the genetic algorithm is shown in FIG. 7. Figure 7 When the algorithm iteration reaches the 50th generation, the weighted average change value of the fitness function value has reached the preset fitness function value deviation threshold. The optimized eddy current damper structure parameter results are as follows.

[0107] Table 3 Value range of variables to be optimized of the eddy current damper

[0108]

[0109] After completing the variable optimization, the performance of the optimized muzzle eddy current damper is accurately investigated through simulation, the model of the application is assembled with the tank multi-body system dynamics model, and the influence law and damping characteristics of the eddy current damper on the muzzle vibration are deeply explored by comparing and analyzing specific working conditions.

[0110] Figure 8 is the input torque curve; Figure 9 is the muzzle high-low angle displacement comparison curve; Figure 10 is the muzzle high-low linear displacement comparison curve. Combined with Figures 8-10The driving torque is input at the rocking frame ear, and the gun muzzle height and linear displacement are obtained by simulation calculation. The results show that the gun muzzle vibration is better in the working condition with damper and damping force, so the designed gun muzzle eddy current damper can provide energy dissipation from the aspects of mechanical structure and eddy current damping force, and has a certain degree of inhibition effect on the nonlinear vibration of the barrel.

[0111] The technical features of the above embodiments can be combined in any manner. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present disclosure.

[0112] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A muzzle eddy current damper for a tank gun, characterized in that The front platform includes a magnetic conductive outer ring (1), a front end fastener (3) and a conductor inner ring (6), the conductor inner ring (6) is connected with the magnetic conductive outer ring (1), the magnetic conductive outer ring (1) is connected with the front end fastener (3), and the front end fastener (3) is fixed with the barrel outer wall; the rear platform includes a fixator (12) and a flexible rod (13), and the fixator (12) is fixed with the barrel outer wall; the moving platform includes a permanent magnet (7) and a base (8), the permanent magnet (7) is connected with the base (8), and the base (8) is connected with the flexible rod (13); the moving platform can produce relative movement relative to the front platform and the rear platform. The magnetic conductive outer ring (1), the front end fastener (3), the conductor inner ring (6), the permanent magnet (7), the base (8) and the fixator (12) are coaxially rotationally symmetrical in design, are centrally perforated and are sleeved on the barrel; the permanent magnet (7) adopts a Halbach array magnetic circuit structure, the magnetization directions of the permanent magnet units are sequentially rotated by 90 degrees along the radial direction, and the conductor inner ring (6) and the magnetic conductive outer ring (1) jointly form a complete two-dimensional axisymmetric magnetic circuit structure, the strong magnetic induction lines generated by the permanent magnet (7) arranged in the Halbach array pass through the working air gap into the conductor inner ring (6), and after forming a loop through the magnetic conductive outer ring (1), the strong magnetic induction lines return to the permanent magnet (7) through the air gap again, thereby forming a complete magnetic flux path.

2. The muzzle eddy current damper for a tank gun according to claim 1, characterized in that The front platform includes a magnetic conductive outer ring (1), a first screw (2), a front end fastener (3), a first gasket (4), a third screw (5) and a conductor inner ring (6), the conductor inner ring (6) and the magnetic conductive outer ring (1) are homogeneous solid rings, and the two are connected through a magnetic adhesive; the outer surface of the magnetic conductive outer ring (1) has four rotationally symmetrical threaded blind holes, the front end fastener (3) is in a hollow cylindrical structure, four threaded holes are arranged at positions corresponding to the contact surface of the magnetic conductive outer ring (1), the magnetic conductive outer ring (1) is fixed with the front end fastener (3) through the first screw (2), the side surface of the front end fastener (3) is provided with four rotationally symmetrical threaded holes, the front end fastener (3) is sleeved on the barrel outside and is fastened with the barrel outer wall through the third screw (5), and the first gasket (4) is sleeved on the rod portion of the first screw (2).

3. The muzzle eddy current damper for a tank gun according to claim 2, characterized in that The magnetic conductive outer ring (1) is made of an iron-silicon-aluminum magnetic powder core, and the front end fastener (3) is made of carbon fiber; the conductor inner ring (6) is made of copper.

4. The muzzle eddy current damper for a tank gun as claimed in claim 1, wherein, In the moving platform, the permanent magnet (7) is an annularly arranged permanent magnet array and is fixed on the base (8) through a magnetic adhesive; the outer side of the rear end surface of the base (8) has four rotationally symmetrical threaded guide holes, and the flexible rod (13) is connected with the fixator (12) of the rear platform.

5. The muzzle eddy current damper for a tank gun according to claim 4, characterized in that The permanent magnet (7) is designed in a circular ring shape, the magnetization directions of the permanent magnet units in the permanent magnet array are alternately arranged along the radial direction of the permanent magnet (7) according to the Halbach array rule, and a strong magnetic field region parallel to the lower surface of the conductor inner ring (6) is formed above the upper end surface of the permanent magnet (7).

6. The muzzle eddy current damper for a tank gun as claimed in claim 4, wherein, The permanent magnet (7) is made of N52 sintered neodymium iron boron, and the base (8) is made of carbon fiber material.

7. The muzzle eddy current damper for tank gun as claimed in claim 1 wherein, The rear platform comprises a second screw (9), a nut (10), a second gasket (11), a fixer (12) and flexible rods (13), the front end surface of the fixer (12) is provided with four through holes in a rotationally symmetrical manner at the same position of the threaded guide hole of the rear end surface of the base (8), the flexible rods (13) are four homogeneous low-rigidity solid long rods, the front ends of the rods are inserted into the guide holes of the base (8), the rear ends of the rods are connected with the through holes of the fixer (12), the fixer (12) and the base (8) are fixed by three groups of nuts (10), and the second gasket (11) is arranged at the connecting position; the fixer (12) is in a hollow cylindrical structure, four rotationally symmetrical threaded holes are formed in the side surface of the fixer (12), the fixer (12) is sleeved on the outer wall of the barrel, and the fixer (12) is fastened to the outer wall of the barrel by the second screw (9).

8. The muzzle eddy current damper for a tank gun according to claim 7, characterized in that The fixer (12) is made of carbon fiber material, and the flexible rods (13) are made of 6061-T6 aluminum alloy.

9. The muzzle eddy current damper for tank gun as claimed in claim 1 wherein, The strong magnetic induction lines generated by the Halbach array of permanent magnets (7) pass through the working air gap into the inner conductor ring (6), form a loop through the magnetic conducting outer ring (1), and then pass through the air gap to return to the permanent magnet (7) to form a complete magnetic flux path. The magnetic flux path includes the following elements: R bi is the magnetic resistance of the magnetic flux path in the outer ring; R gm is the magnetic resistance of the main magnetic flux path through the inner conductor ring; R l is the magnetic resistance of the leakage magnetic flux path in the air gap, which is derived from the average length and average volume of the leakage magnetic flux path; R pm,i is the magnetic resistance of each permanent magnet unit; F pm is the magnetic motive force of the permanent magnet; Five key parameters of the Eddy current damper are selected as design optimization variables, which are: air gap thickness g, conductor inner ring thickness h ct , magnetic conductive outer ring thickness h bi , permanent magnet axial thickness h m , permanent magnet circumferential arrangement angle interval θ MEC , and the electric eddy current resistance F is calculated further according to the magnetic circuit structure analysis. (1) According to the magnetic circuit structure of the eddy current damper, the eddy current resistance F is derived MEC , with the objective function of maximizing the eddy current resistance F MEC , and the upper and lower limits of the key parameters under the conditions of ensuring the magnetic field gain and the structural reliability as the constraint conditions, an optimization problem model is constructed: In the formula, f(X) is F MEC The corresponding objective function, and are the upper and lower limits of the value of each design variable to be optimized, respectively. (2) Latin hypercube sampling (LHS) is used to obtain a sample library; (3) a BP neural network is created; (4) Using the error square R 2 Test the accuracy of the training results; (5) a genetic algorithm is used to globally optimize and solve the proxy model.

10. The muzzle eddy current damper for a tank gun as claimed in claim 1, wherein, When the barrel vibrates, the front end fastener (3) and the fixer (12) are sleeved and fixed on the outer wall of the barrel, and are relatively static with the barrel, and the base (8) moves relatively with the barrel due to the existence of the flexible rods (13), at this time, the strong magnetic induction lines generated by the permanent magnet (7) installed on the base (8) cut the conductor inner ring (6), and an eddy current field is excited inside the conductor inner ring (6); according to the principle of electromagnetic induction, the eddy current will generate an induced magnetic field in the opposite direction of the original magnetic field, and the interaction of the two magnetic fields will form an eddy current damping force in the opposite direction of the relative motion trend, that is, an eddy current damping effect that hinders the relative displacement of the moving part is generated, the direction of the damping force is always opposite to the motion direction, thereby hindering the barrel vibration and realizing effective dissipation of vibration energy.

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