Test method and system for output characteristics of electro-acoustic transducer considering inconsistency of rod

Abstract

The application discloses a kind of considering the output characteristic test method and system of electroacoustic transducer rod inconsistency.It includes: step A: make the electroacoustic transducer be single output mode, according to the pre-stress that rod is subjected to, the magnetization intensity of each rod, based on strain model formula, determine the strain of each rod;Step B: according to the strain of each rod obtained in step A, determine the output force corresponding to each rod;Step C: according to the pre-stress that rod is subjected to, the output force corresponding to each rod obtained in step B, construct the dynamic equation reflecting the output displacement of the electroacoustic transducer and time relationship, so as to obtain the output displacement of the electroacoustic transducer and time relationship in single output mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of output characteristic test of magnetostrictive material rod in electro-acoustic transducer, and particularly relates to an output characteristic test method and system of electro-acoustic transducer considering rod inconsistency. BACKGROUND

[0002] The magnetostrictive electro-acoustic transducer has been widely applied in underwater sonar, long-distance detection, non-destructive testing and other fields due to its fast response speed, high energy density and large output force. In order to further meet the engineering requirements of high load and large thrust, the structure of parallel driving of multiple magnetostrictive rods has become the mainstream design form of high-power electro-acoustic transducers. For such parallel electro-acoustic transducers, establishing an accurate output characteristic model is a prerequisite for high-precision control. Most of the current theoretical models are based on idealized assumptions, that is, all the magnetostrictive rods in the parallel system have completely consistent physical properties and magnetization characteristics, so the output of the multi-rod system is simplified as the linear superposition of the performance of a single rod. This assumption seriously restricts its use and promotion.

[0003] In actual preparation and engineering application, due to the factors such as randomness of crystal growth orientation, unevenness of heat treatment process and material cutting error, even for the same batch and same specification of magnetostrictive rods, there are still individual differences (i.e. inconsistency) in key performance parameters such as magnetization curve and saturation magnetostriction coefficient. In the rigid coupling structure of double rods or multiple rods in parallel, this inconsistency will lead to uneven output of each branch rod, causing the impedance of the system to deviate and the resonance characteristics to change. The existing modeling method based on the assumption of "rod consistency" cannot represent this objectively existing difference, resulting in a large deviation between the displacement-time curve predicted by the model and the actual output displacement-time curve, which seriously restricts the application and performance optimization of the parallel magnetostrictive electro-acoustic transducer structure. SUMMARY

[0004] The problem to be solved by the present application is that in the modeling of the structure of parallel driving of multiple magnetostrictive rods, the modeling method based on the consistency of rod performance leads to a large deviation between the displacement-time curve predicted by the model and the actual output displacement-time curve, and an output characteristic test method of electro-acoustic transducer considering rod inconsistency is provided.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is: an output characteristic test method of electro-acoustic transducer considering rod inconsistency, the electro-acoustic transducer comprising J rods arranged in parallel, the rods being magnetostrictive rods; J≥2; an excitation coil is arranged outside each rod; the excitation coils are connected in series to form a series circuit;

[0006] The electro-acoustic transducer has a single output mode; when the electro-acoustic transducer is in the single output mode, the electro-acoustic transducer comprises a first output rod, each rod abuts the first output rod, and a far end of the first output rod from the rods forms an output end of the electro-acoustic transducer; in a projection plane perpendicular to an axial direction of the rods, projections of the J rods are uniformly arranged in a circumferential direction of the projection of the first output rod.

[0007] The electro-acoustic transducer output characteristic test method comprises:

[0008] Step A: When the electro-acoustic transducer is in the single output mode, the same pre-stress is applied to each rod, and the strain of each rod is determined based on the pre-stress received by the rod and the corresponding bulk magnetization of each rod according to a strain model formula.

[0009] Step B: The output force corresponding to each rod is determined according to the strain of each rod obtained in Step A.

[0010] Step C: The output displacement-time relationship of the electro-acoustic transducer is obtained by constructing a dynamic equation reflecting the output displacement-time relationship of the electro-acoustic transducer according to the pre-stress received by the rod and the output force corresponding to each rod obtained in Step B.

[0011] According to the same inventive concept, the present application also provides an electro-acoustic transducer output characteristic test system considering rod inconsistency, comprising:

[0012] A computer device or a processor configured or programmed to execute the steps of the electro-acoustic transducer output characteristic test method described above.

[0013] A pre-tightening mechanism for applying pre-stress to each rod.

[0014] A power supply module for supplying power to the series circuit.

[0015] When the electro-acoustic transducer is in the single output mode, the electro-acoustic transducer further comprises a first pressure sensor for measuring the pre-stress received by the rod.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] 1. The application proposes a kind of output characteristic test method considering the inconsistency of bar. Unlike the processing mode of the double bar being simplified as single bar multiplication in traditional model, the method proposed in the application respectively establishes independent dynamic magnetization and strain model for two bars, and introduces eddy current loss and abnormal loss correction, and finally carries out mechanical coupling through dynamics equation. The method can effectively capture the performance difference of bar caused by manufacturing process, improve the prediction accuracy of the output displacement of electroacoustic transducer under different frequencies and power excitation. The method of the application has guiding significance for the optimization design of parallel type magnetostrictive electroacoustic transducer modeling.

[0018] 2. The application designs a kind of test system of electroacoustic transducer with unique structure and using multiple bars in parallel, and the output mechanism thereof can be flexibly switched between "double output mode" and "single output mode". In double output mode, the displacement and prestress data of two bars can be independently obtained, so as to carry out corresponding test, and in single output mode, the overall performance after coupling can be verified. This design provides reliable hardware basis for solving the consistency problem in multiple bar parallel structure. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 It is the principle diagram of the electroacoustic transducer output characteristic test system considering the inconsistency of bar in the embodiment of the application;

[0021] Figure 2 It is the schematic diagram of Figure 1 electroacoustic transducer in single output mode and double output mode switching;

[0022] Figure 3 It is the schematic diagram of the electroacoustic transducer in single output mode in the embodiment of the application;

[0023] Figure 4 It is the sectional view of Figure 3 ;

[0024] Figure 5 It is the schematic diagram of the electroacoustic transducer in double output mode in the embodiment of the application;

[0025] Figure 6 It is the sectional view of Figure 5 ;

[0026] Figure 7is an enlarged schematic view of the rod and permanent magnet part of the electro-acoustic transducer of the embodiment of the present application;

[0027] Figure 8 is the current-displacement curve of the plurality of rods of the same specification in a static state obtained by the embodiment of the present application;

[0028] Figure 9 is the current-displacement curve of the plurality of rods of the same specification in a dynamic state obtained by the embodiment of the present application;

[0029] Figure 10 is a comparison diagram of the displacement-time curve obtained by the output characteristic test method of the embodiment of the present application and the measured curve;

[0030] Figure 11 is a comparison diagram of the voltage-current relationship curve obtained by the embodiment of the present application when the frequency is set to 100 Hz according to the experimental results, the method of the present application, and the ordinary equivalent circuit model;

[0031] Figure 12 is a comparison diagram of the voltage-current relationship curve obtained by the embodiment of the present application when the frequency is set to 300 Hz according to the experimental results, the method of the present application, and the ordinary equivalent circuit model;

[0032] Figure 13 is a comparison diagram of the voltage-current relationship curve obtained by the embodiment of the present application when the frequency is set to 600 Hz according to the experimental results, the method of the present application, and the ordinary equivalent circuit model;

[0033] Figure 14 is a comparison diagram of the current-displacement relationship curve obtained by the embodiment of the present application when the frequency is set to 100 Hz according to the experimental results, the method of the present application, and the existing superposition model;

[0034] Figure 15 is a comparison diagram of the current-displacement relationship curve obtained by the embodiment of the present application when the frequency is set to 200 Hz according to the experimental results, the method of the present application, and the existing superposition model;

[0035] Figure 16 is a comparison diagram of the current-displacement relationship curve obtained by the embodiment of the present application when the frequency is set to 300 Hz according to the experimental results, the method of the present application, and the existing superposition model;

[0036] Figure 17 is a comparison diagram of the current-displacement relationship curve obtained by the embodiment of the present application when the frequency is set to 500 Hz according to the experimental results, the method of the present application, and the existing superposition model.

[0037] In the above figures:

[0038] 111, first pad; 112, second pad; 121, first magnetic conducting block; 122, second magnetic conducting block; 13, rod; 14, permanent magnet; 15, magnetic yoke; 17, induction coil;

[0039] 21, first displacement sensor; 22, second displacement sensor; 20, sensor mounting frame;

[0040] 31, first output rod; 310, first mounting seat; 32, second output rod; 320, second mounting seat;

[0041] 4, pre-tightening bolt;

[0042] 51, first pre-tightening end cover; 52, second pre-tightening end cover; 510, first through hole; 520, second through hole;

[0043] 6, excitation coil;

[0044] 7, magnetic circuit cover plate;

[0045] 8, base; 81, bottom plate; 82, top plate; 83, vertical plate;

[0046] 91, first pressure sensor; 92, second pressure sensor;

[0047] 101, first disc spring; 102, second disc spring. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0049] The present application provides a kind of considering the output characteristic test method of bar inconsistency of electroacoustic transducer, electroacoustic transducer includes J mutually parallel arranged rods 13, the rod 13 is magnetostrictive rod, preferably supermagnetostrictive rod;J≥2;Each rod 13 outside corresponding winding has excitation coil 6;Each excitation coil 6 is mutually connected in series to form series circuit;

[0050] The electroacoustic transducer has single output mode;When electroacoustic transducer is single output mode, electroacoustic transducer includes first output rod 31, each rod 13 is all abutted to first output rod 31, the end of first output rod 31 away from rod 13 forms the output end of the electroacoustic transducer;In the projection plane vertical to the axial direction of rod 13, the projection of J rods 13 is evenly arranged in the circumferential direction of the projection of first output rod 31;

[0051] The electro-acoustic transducer output characteristic test method comprises:

[0052] Step A: the electro-acoustic transducer has a single output mode, the same prestress is applied to each rod 13, the strain of each rod is determined according to the prestress received by the rod 13 and the corresponding bulk magnetization of each rod, and the strain model formula is used as the basis;

[0053] Step B: the output force corresponding to each rod is determined according to the strain of each rod obtained in step A;

[0054] Step C: the dynamic equation reflecting the relationship between the output displacement of the electro-acoustic transducer and time is constructed according to the prestress received by the rod 13 and the output force corresponding to each rod obtained in step B, so as to obtain the relationship between the output displacement of the electro-acoustic transducer and time in the single output mode.

[0055] According to the above scheme of the present application, the bulk magnetization of each rod is calculated considering the inconsistency of the rods, the strain of the rod is calculated, the output force corresponding to the rod is calculated according to the strain, and the dynamic equation is constructed according to the output force of each rod, so as to determine the relationship between the output displacement and time according to the dynamic equation.

[0056] When the electro-acoustic transducer is in a single output mode, the extension direction of the rod 13 is parallel to the extension direction of the first output rod 31. When the electro-acoustic transducer is in a multiple output mode, the extension direction of the rod 13 is parallel to the extension direction of the second output rod 32.

[0057] Each rod 13 has the same specification.

[0058] The dynamic equation is:

[0059] Formula Eq1: ;

[0060] Wherein: M eq , C eq , K eq respectively correspond to the equivalent mass, equivalent damping and equivalent stiffness of the axial vibration component; x is the output displacement of the electro-acoustic transducer; t is time; σ is the prestress received by the rod 13; A r is the cross-sectional area of the rod 13, F G,j is the output force corresponding to the jth rod 13 obtained in step B; j=1, 2, …, J; J is the number of rods 13 in the electro-acoustic transducer; J≥2; the axial vibration component is the whole structure moving in the axial direction of the rod 13 in the electro-acoustic transducer.

[0061] The number of J is preferably even, preferably, the magnetic field of the two adjacent rods constitutes a magnetic circuit, that is, the magnetic poles of the magnetic field corresponding to the two adjacent rods are opposite, one of which forms a magnetic field with an upper N pole and a lower S pole, and the other forms a magnetic field with an upper S pole and a lower N pole, thereby forming a magnetic circuit.

[0062] Further, the two ends of the rod 13 in the axial direction are fixedly connected with permanent magnets 14.

[0063] Further, when the electro-acoustic transducer is in a single output mode: the electro-acoustic transducer further comprises a first pre-tightening end cover 51 detachably connected with the transducer base; the first pre-tightening end cover 51 is provided with a first through hole 510 corresponding to the first output rod 31; the first output rod 31 is fixed to the first mounting seat 310, and each rod 13 abuts against the first mounting seat 310 away from the first output rod 31, thereby abutting against the first output rod 31; the first output rod 31 extends in the axial direction of the rod 13 away from the rod 13, and passes through the first through hole 510; the end of the rod 13 close to the first mounting seat 310 is connected with the first mounting seat 310 through the permanent magnet 14 and the magnetic conducting block in sequence; the first pre-tightening end cover 51 abuts against the first mounting seat 310 through the annular structure sleeved outside the first output rod 31, thereby applying the same pre-stress to each rod 13; the annular structure comprises a first disc spring 101 and a first pressure sensor 91 arranged in sequence; the magnetic conducting block arranged between the rod 13 and the first mounting seat 310, the rod 13, the permanent magnet 14 fixedly connected with the rod 13, the annular structure, and the first output rod 31 constitute the axial vibration component. In this embodiment, the end of the rod 13 close to the first mounting seat 310 is connected with the first mounting seat 310 through the permanent magnet 14 and the first magnetic conducting block 121 in sequence, and the magnetic conducting block arranged between the rod 13 and the first mounting seat 310 is the first magnetic conducting block 121.

[0064] Through the above arrangement, the first pre-tightening end cover can be used to apply pre-stress to each rod, and the first output rod 31 passes through the first through hole 510, so that the axial vibration component will not be disturbed by the first pre-tightening end cover when moving. Each rod is simultaneously pre-stressed by the first mounting seat 310 and receives the output force of each rod, and a single output can be formed through the first output rod 31.

[0065] The formula of the output force corresponding to the jth rod is:

[0066] Formula Eq2: F G,j =A r E H,j λ j ;

[0067] Wherein: A r is the cross-sectional area of the rod 13, EH,j Yong's modulus of the jth rod 13; λ j Strain of the jth rod 13 obtained in step A; wherein Yong's modulus of different rods can be measured by existing methods.

[0068] When σ≤σ s , the strain model formula is:

[0069] Formula Eq31: ;

[0070] When σ>σ s , the strain model formula is:

[0071] Formula Eq32: ;

[0072] Wherein: λ j Strain of the jth rod, σ s Saturation prestress corresponding to the rod 13, σ max Maximum bearing stress corresponding to the rod 13, i.e. the maximum stress that the rod material can bear, tanh(2σ / σ s ) is the hyperbolic tangent function of 2σ / σ s , λ s,j Indicates the saturation magnetostriction coefficient of the jth rod 13, M j Bulk magnetization of the jth rod 13, M s,j Saturation magnetization of the jth rod 13.

[0073] Through the above setting, the strain of each rod in the multi-rod parallel structure can be calculated according to the corresponding parameters of different rods, so as to consider the difference of the performance of different rods in the multi-rod parallel structure.

[0074] Further, J is an even number: two permanent magnets 14 corresponding to the rod 13 are respectively fixedly connected with the upper surface and the lower surface of the rod 13; the number of turns of each excitation coil 6 is the same; for two adjacent excitation coils 6 in the circumferential direction, the N pole of the magnetic field generated by one excitation coil and the N pole of the magnetic field generated by the other excitation coil are located on opposite sides in the height direction; the N poles of the two permanent magnets 14 corresponding to the same rod are located on the same side in the height direction; for two adjacent rods 13 in the circumferential direction, the N pole of the permanent magnet 14 corresponding to one of the rods and the N pole of the permanent magnet 14 corresponding to the other rod are located on opposite sides in the height direction.

[0075] For example, the N pole and the S pole of each permanent magnet 14 corresponding to the same rod are respectively located at the bottom end and the top end, or the N pole and the S pole are respectively located at the top end and the bottom end.

[0076] For example, if the N-pole and S-pole of one excitation coil 6 are at the top end and bottom end respectively, then the N-pole and S-pole of the excitation coil 6 adjacent to it in the circumferential direction are at the bottom end and top end respectively.

[0077] For example, if the N-pole and S-pole of one excitation coil 6 are at the top end and bottom end respectively, then the N-pole and S-pole of the excitation coil 6 adjacent to it in the circumferential direction are at the bottom end and top end respectively.

[0078] For example, if the N-pole and S-pole of one excitation coil 6 are at the top end and bottom end respectively, then the N-pole and S-pole of the excitation coil 6 adjacent to it in the circumferential direction are at the bottom end and top end respectively.

[0079] Further, the following formulas are combined to determine the volume magnetization Mj corresponding to the jth rod j :

[0080] Formula Eq41: M an,j = M s,j + M e,j ; [coth(H j / as j / H e,j )];

[0081] Formula Eq42: H e,j = H j + αr j M eddy,j (H anom,j + H j );

[0082] Formula Eq43: αr j = α s,j + 9λ j σM s,j / 2μ0(M 2 )

[0083] Formula Eq44: M j = M rev,j + M irr,j ;

[0084] Formula Eq45: M rev,j = c j (M an,j -M irr,j );

[0085] Formula Eq46: dM irr,j / dH=(M an,j -Mirr,j ) / [k j δ-αr j (M an,j -M irr,j )];

[0086] Eq47: ;

[0087] wherein: M j is the bulk magnetization of the jth rod 13; M rev,j is the reversible magnetization of the jth rod 13, M irr,j is the irreversible magnetization of the jth rod 13; c j is the reversible coefficient of the jth rod 13; M an,j is the anhysteretic magnetization of the jth rod 13; H is the effective axial magnetic field strength of the rod 13; k j is the pinning parameter of the jth rod 13; αr j is the average field parameter of the jth rod 13 after correction of interdomain coupling; the current flowing through the excitation coil 6 is a function of time t, denoted as input current i ac (t); G M is the reluctance correction factor, N is the number of turns of the excitation coil 6; B r is the residual magnetic induction of the permanent magnet 14; L GMM is the size of the rod 13 in the axial direction of the rod 13, i.e. the length of the rod; L PM is the size of the permanent magnet 14 in the axial direction of the rod 13, i.e. the length of the permanent magnet; μ GMM is the relative permeability of the rod 13, μ PM is the relative permeability of the permanent magnet 14, μ0 is the vacuum permeability; M s,j is the saturation magnetization of the jth rod 13; H e,j is the magnetic field strength of the effective field inside the jth rod 13; as j is the shape coefficient of the anhysteretic magnetization of the jth rod 13, λ s,j denotes the saturation magnetostriction coefficient of the jth rod 13; H eddy,j is the eddy current loss magnetic field strength of the jth rod 13; H anom,j is the abnormal loss magnetic field strength of the jth rod 13; α j is the average field parameter of the interdomain coupling of the jth rod 13; δ is a direction parameter; δ = 1 when dH / dt≥0; δ = -1 when dH / dt<0.

[0088] By performing independent calculations for each rod, the bulk magnetization corresponding to each rod can be determined, thereby taking into account the differences in performance of different rods in a multi-rod parallel structure.

[0089] Further, the electro-acoustic transducer also has multiple output modes;

[0090] When the electro-acoustic transducer is in the multiple output mode, the electro-acoustic transducer comprises a second output rod 32 corresponding to each rod 13, the rod 13 abuts against the corresponding second output rod 32, and one end of each second output rod 32 away from the corresponding rod 13 forms one output end of the electro-acoustic transducer, and each output end of the electro-acoustic transducer is independent of each other; the rod 13 and the corresponding second output rod 32 are coaxially arranged;

[0091] Further, the step A further comprises a step PA1 and a step PA2 before the step A;

[0092] The step PA1: adjusting the electro-acoustic transducer to be in the multiple output mode, and respectively applying a pre-stress to each rod 13, and measuring the displacement of each second output rod 32 in the axial direction of the rod 13;

[0093] The step PA2: determining the reversible coefficient c of each rod 13 according to the pre-stress applied to each rod 13 and the displacement of the corresponding second output rod 32 in the axial direction of the rod 13. j , the pinning parameter k j , the saturation magnetization M s,j , the shape coefficient as of the non-hysteresis magnetization j , the saturation magnetostriction coefficient λ s,j , the eddy current loss magnetic field strength H eddy,j , the abnormal loss magnetic field strength H anom,j , the average field parameter α of inter-domain coupling j , so as to determine the bulk magnetization of each rod.

[0094] In the step A, each rod 13 is adjusted to be in the single output mode.

[0095] Through the above arrangement, the electro-acoustic transducer is switched between the single output mode and the multiple output mode. When in the multiple output mode, each rod can independently output, and the pre-stress applied to each rod 13 and the displacement of the corresponding second output rod 32 in the axial direction of the rod 13 are independently measured, so as to determine the corresponding parameters of each rod, and further determine the bulk magnetization of the rod. In the step A, the electro-acoustic transducer is adjusted to be in the single output mode, so as to realize the output characteristic test of the electro-acoustic transducer in the single output mode.

[0096] The method for determining the parameters of each rod according to the pre-stress on each rod and the displacement of the corresponding second output rod in the axial direction of the rod in step PA2 is prior art. In addition, the number of turns of the excitation coil 6, the size in the axial direction of the rod, the size of the permanent magnet in the axial direction of the rod, the residual magnetic induction intensity of the permanent magnet 14, the vacuum permeability, the relative permeability of the rod 13, and the relative permeability of the permanent magnet 14 are all known parameters. The meaning of the magnetic resistance correction factor is that in addition to the magnetic resistance already considered in the calculation, there is also leakage magnetic induction. By introducing the magnetic resistance correction factor, these leakage magnetic inductions can be corrected, thereby improving the calculation accuracy of the magnetic field. The magnetic resistance correction factor can be approximately calculated by finite element simulation according to the comsol simulation software. The calculation of the magnetic resistance correction factor is prior art.

[0097] The current flowing through the excitation coil 6 is a function of time t, denoted as input current i ac (t);

[0098] Further, the electro-acoustic transducer output characteristic test method further comprises: obtaining the relationship between the input current and the output displacement according to the expression of the input current i ac (t), and the output displacement-time relationship of the electro-acoustic transducer obtained in step C.

[0099] Through the above arrangement, the relationship between the input current and the output displacement can also be obtained during the output characteristic test.

[0100] Each rod 13 has the same specification; each excitation coil 6 has the same number of turns; J is an even number; the two permanent magnets 14 corresponding to the rod 13 are fixedly connected to the upper surface and the lower surface of the rod 13, respectively; for two adjacent excitation coils 6 in the circumferential direction, the N poles of the magnetic field generated by one excitation coil and the N poles of the magnetic field generated by the other excitation coil are located on opposite sides in the height direction; the N poles of the two permanent magnets 14 corresponding to the same rod are located on the same side in the height direction; for two adjacent rods 13 in the circumferential direction, the N poles of the permanent magnet 14 corresponding to one rod and the N poles of the permanent magnet 14 corresponding to the other rod are located on opposite sides in the height direction. In the present application, each rod 13 has the same specification, which means that the shape, size, material, and preparation process parameters of each rod 13 are consistent.

[0101] Further, the expression of the input current i ac (t) is determined according to the following formula:

[0102] Formula Eq5:

[0103] ;

[0104] Wherein, the voltage applied at both ends of the series circuit is a function of time t, denoted as u(t); R is the equivalent impedance of all excitation coils 6; N is the number of turns of the excitation coil 6; A r is the cross-sectional area of the rod 13, μ0 is the vacuum permeability; δ M,j is the magnetization state switching parameter corresponding to the jth rod 13;

[0105] When (dH / dt)(M an,j -M j )≤0, δ M,j =0; When (dH / dt)(M an,j -M j )>0, δ M,j =1.

[0106] In the prior art, the input current is generally calculated by a common equivalent circuit model, that is, the input current is calculated by dividing the voltage applied at both ends of the series circuit by the equivalent impedance of the series circuit. Compared with the prior art, the input current is determined by the above formula Eq5, the electrical-magnetic nonlinear coupling is considered, the current distortion caused by the nonlinear of the magnetic core can be reflected, and the problem of inaccurate output characteristic prediction caused by current distortion is solved.

[0107] According to the same inventive concept, the application further provides an electro-acoustic transducer output characteristic test system considering rod inconsistency, comprising:

[0108] A computer device or a processor configured or programmed to perform the steps of the above-mentioned electro-acoustic transducer output characteristic test method;

[0109] A pre-tightening mechanism for applying pre-stress to each rod 13;

[0110] A power supply module for supplying power to the series circuit;

[0111] When the electro-acoustic transducer is a single output mode, the electro-acoustic transducer further comprises a first pressure sensor 91 for measuring the pre-stress received by the rod 13.

[0112] Further, the electro-acoustic transducer comprises a transducer base;

[0113] When the electro-acoustic transducer is in single output mode, the pre-tightening mechanism is a first pre-tightening end cover 51 detachably connected with the transducer base; the first pre-tightening end cover 51 is provided with a first through hole 510 corresponding to the first output rod 31; the first output rod 31 is fixed to the first mounting seat 310, and each rod 13 abuts against the first mounting seat 310 away from the first output rod 31, thereby abutting against the first output rod 31; the first output rod 31 extends in the axial direction of the rod 13 away from the rod 13 and passes through the first through hole 510; the first pre-tightening end cover 51 abuts against the first mounting seat 310 through the first disc spring 101 and the first pressure sensor 91 sleeved outside the first output rod 31, thereby applying the same pre-stress to each rod 13.

[0114] A first spacer 111 can be arranged between the first disc spring 101 and the corresponding first pressure sensor 91, thereby adapting the distance between the first pre-tightening end cover 51 and the first mounting seat 310.

[0115] The electro-acoustic transducer also has a multi-output mode.

[0116] When the electro-acoustic transducer is in multi-output mode: the pre-tightening mechanism is a second pre-tightening end cover 52 detachably connected with the transducer base; the electro-acoustic transducer further comprises a second output rod 32, a second pressure sensor 92, a second disc spring 102 and a displacement sensor corresponding to the rod 13; the second pre-tightening end cover 52 is provided with a second through hole 520 corresponding to each second output rod 32; the displacement sensor is used to measure the displacement of the corresponding second output rod 32 in the axial direction of the rod 13; the second output rod 32 is fixed to the corresponding second mounting seat 320, and the rod 13 abuts against the corresponding second mounting seat 320 away from the corresponding second output rod 32, thereby abutting against the corresponding second output rod 32; the second output rod 32 extends in the axial direction of the rod 13 away from the rod 13 and passes through the corresponding second through hole 520; the second pre-tightening end cover 52 abuts against the second mounting seat 320 corresponding to the second output rod 32 through the corresponding second disc spring 102 and the corresponding second pressure sensor 92 sleeved outside each second output rod 32, thereby applying pre-stress to each rod 13; the end of each second output rod 32 away from the corresponding rod 13 forms one of the output ends of the electro-acoustic transducer, and each output end of the electro-acoustic transducer is independent of each other; the rod 13 and the corresponding second output rod 32 are coaxially arranged. A second spacer 112 can be arranged between the second disc spring 102 and the corresponding second pressure sensor 92, thereby adapting the distance between the second pre-tightening end cover 52 and the second mounting seat 320.

[0117] Among them, the multi-output mode means that the electro-acoustic transducer has at least two independent outputs.

[0118] The first output rod 31 has a gap between the wall surface of the corresponding first through hole 510, so that the axially vibrating rod 13 does not interfere with the movement of the first output rod 31 when driving the first output rod 31 to vibrate.

[0119] The second output rod 32 has a gap between the wall surface of the corresponding second through hole 520, so that the axially vibrating rod 13 does not interfere with the movement of the second output rod 32 when driving the second output rod 32 to vibrate.

[0120] As shown in Figures 3-6 , the base 8 is provided with a transducer base, which can be a frame structure surrounded by a bottom plate 81, a top plate 82, and two side plates 83. Of course, the transducer base is not limited to this structure, and other commonly used base forms can also be used. The inside of the frame structure accommodates the vibrator module, i.e. the rod 13 and the corresponding permanent magnet 14. The pre-tightening end cap can be detachably connected to the transducer base by the pre-tightening bolt 4. As shown in Figure 3 , Figure 4 , the first pre-tightening end cap 51 is detachably connected to the side plate 83 by the pre-tightening bolt 4. As shown in Figure 5 , Figure 6 , the second pre-tightening end cap 52 is detachably connected to the side plate 83 by the pre-tightening bolt 4.

[0121] As shown in Figures 3-6 , the bottom plate 81, the top plate 82, and the two side plates 83 are provided with grooves for accommodating the magnetic yoke 15, and the corresponding magnetic yoke 15 can be provided with a magnetic circuit cover plate 7. The magnetic circuit cover plate 7 can be an epoxy plate to prevent the magnetic yoke below the permanent magnet from being attracted up during disassembly.

[0122] In Figures 3-6 the structure, the rod 13, the permanent magnet 14, the magnetic yoke 15, the first magnetic guide block 121, the second magnetic guide block 122, and the magnetic yoke 15 form a magnetic guide circuit. The rod 13 is connected to the transducer base through the permanent magnet 14 below the rod 13, the second magnetic guide block 122 in sequence. The transducer base is supported by the second magnetic guide block 122, thereby achieving support for the rod 13. The second magnetic guide block 122 only contacts the permanent magnet 14 above, but is not fixedly connected to the permanent magnet 14.

[0123] The first displacement sensor and the second displacement sensor can be fixedly installed through the sensor mounting bracket 20.

[0124] The first pre-tightening end cap 51 abuts against the first mounting seat 310 through the first disc spring 101, the first pad 111, and the first pressure sensor 91 in sequence, so that the first mounting seat 310 abuts against each rod 13, thereby providing a pre-tightening force.

[0125] The present application designs a unique structure of electro-acoustic transducer test system, the output mechanism can be switched between "double output mode" and "single output mode". In double output mode, the displacement and prestress data of two rods can be obtained independently, so as to accurately identify the two sets of different material parameters, and intuitively show the inconsistency of the rods; in single output mode, the overall performance after coupling can be verified. This design provides a reliable hardware foundation for solving the consistency problem in multiple rod parallel structure.

[0126] Unlike the traditional model which simplifies the system of double rod parallel output as single rod multiplication, the present application respectively establishes independent dynamic magnetization and strain model for the two rods, and introduces eddy current loss and abnormal loss correction, and finally performs mechanical coupling through dynamic equation. The present application can prove the inconsistency of the rods in double rod parallel structure, and effectively quantify the performance difference of the rods, and realize the prediction of the overall output characteristics of the electro-acoustic transducer based on the differentiated parameters. The method can effectively capture the performance difference of the rods caused by manufacturing process, improve the prediction accuracy of the output displacement of the electro-acoustic transducer under different frequencies and current excitation, and has guiding significance for the optimization design of parallel type giant magnetostrictive electro-acoustic transducer.

[0127] The present application will be further described below.

[0128] As shown in Figures 1-7 , the present application proposes an electro-acoustic transducer output characteristic test method and test system considering rod inconsistency. The test system can be configured as single output mode or double output mode, so as to obtain single rod characteristics and overall characteristics, and adapt to different test requirements. The present embodiment takes two rods as an example to illustrate, and the multiple output mode is double output mode.

[0129] Figure 1 is the principle diagram of the electro-acoustic transducer output characteristic test system considering rod inconsistency of the present embodiment, Figure 2 is a schematic diagram showing Figure 1 the switching of the electro-acoustic transducer in single output mode and double output mode.

[0130] As shown in Figure 5 , Figure 6 , the double rod parallel type electro-acoustic transducer includes a vibrator module, a magnetic circuit module, a pre-tightening mechanism, an output module and an excitation module. The test system includes a signal acquisition module and a signal processing module. The vibrator module is composed of two rods 13 and corresponding permanent magnets 14; the magnetic circuit module includes a first magnetic conducting block 121, a second magnetic conducting block 122 and a magnetic yoke 15; the pre-tightening mechanism includes a pre-tightening bolt 4, a second pre-tightening end cover 52 and a second disc spring 102. The excitation module includes an excitation coil 6. The excitation coil 6 can be supported by the bottom plate 81 and does not vibrate with the rods.

[0131] The permanent magnets 14 in the vibrator module are symmetrically distributed at the two ends of the two rods 13 in the axial direction, providing a relatively uniform bias magnetic field for the giant magnetostrictive rods. The two rods 13 can be symmetrically distributed, and the rods 13, the permanent magnets 14, the excitation coils 6, the first magnetic conducting blocks 121, the second magnetic conducting blocks 122, and the magnetic yokes 15 together form a magnetic concentrating circuit. The excitation coils are connected in series to ensure that the excitation currents are the same, thereby ensuring that the magnetic field strengths of the two rods are the same. Preferably, the four permanent magnets corresponding to the two rods and the two excitation coils are N-pole and S-pole corresponding, forming a magnetic concentrating circuit. For example Figure 4 In the middle, the magnetic poles formed by the permanent magnets bonded to the left rod and the corresponding excitation coils are both S-pole above and N-pole below, and the magnetic poles formed by the permanent magnets bonded to the right rod and the corresponding excitation coils are both N-pole above and S-pole below, i.e. a magnetic circuit loop as shown by the arrow direction can be formed between the two rods. Figure 4 In the middle, the magnetic poles formed by the permanent magnets bonded to the left rod and the corresponding excitation coils are both S-pole above and N-pole below, and the magnetic poles formed by the permanent magnets bonded to the right rod and the corresponding excitation coils are both N-pole above and S-pole below, i.e. a magnetic circuit loop as shown by the arrow direction can be formed between the two rods.

[0132] As shown in Figure 3 , Figure 4 , in the single output mode of the electro-acoustic transducer, the pre-tightening mechanism includes a threaded connection for adjusting the pre-tightening force, a first pre-tightening end cover 51, and a first disc spring 101 arranged between the first pre-tightening end cover 51 and the rod. The threaded connection is a pre-tightening bolt 4. By rotating the pre-tightening bolt 4, the axial pre-stress applied to the rod can be adjusted. A first pressure sensor 91 is installed below the first disc spring 101 for monitoring the pre-stress. The pre-tightening mechanism is used to apply axial pre-stress to the two giant magnetostrictive rods.

[0133] As shown in Figure 3 , Figure 4 , in the single output mode of the electro-acoustic transducer, the output module includes a first output rod 31.

[0134] As shown in Figure 3 , Figure 4As shown, in the single output mode, the signal acquisition module of the electro-acoustic transducer includes a displacement measurement unit and a force measurement unit. The force measurement unit includes a first pressure sensor 91 for monitoring the axial pre-stress applied to the rod and ensuring the accuracy of the pre-stress. The displacement measurement unit includes a first displacement sensor 21 mounted on a sensor mounting bracket 20 fixedly mounted on the sensor mounting bracket 20. The measurement end of the displacement sensor is arranged opposite the output end of the electro-acoustic transducer in the axial direction of the rod, for measuring the dynamic displacement of the output end in the axial direction. The displacement of the first output rod 31 can be measured by the first displacement sensor, so that the measured displacement can be compared with the output characteristics obtained by testing to verify the effect of the output characteristic testing method of the present application. In the present application, the displacement sensor can be a laser displacement sensor. The signal acquisition module further includes a current sensor for monitoring the excitation current, which can measure the current in the excitation coil 6. The current sensor can use a current probe. Preferably, the signal acquisition module further includes an induction coil 17 for measuring the induced electromotive force of the rod, which can measure the change in magnetic induction intensity in the rod. According to the measurement results of the induction coil 17, the change in magnetic induction intensity in the rod can be determined, so that whether the simulated magnetic induction intensity is accurate can be verified. The induction coil 17 is tightly wound around the surface of the giant magnetostrictive rod. Since the induction coil 17 has a relatively light weight, it can be ignored when determining the equivalent mass, equivalent damping and equivalent stiffness.

[0135] As shown in Figure 3 , Figure 4 , in the single output mode, the transducer adopts a double-rod parallel structure, and both rods 13 are rigidly connected to the first output rod 31 to drive the same first output rod 31. The two rods are coupled to each other and jointly output. In the single output mode, two sets of differentiated material parameters are called to execute the steps of the output characteristic testing method to predict the overall output characteristics after parallel connection. At this time, the overall output displacement of the two rods after coupling is measured. This mode is used to verify the actual output performance of the electro-acoustic transducer with a double-rod parallel structure and the influence of the inconsistency of the rods.

[0136] The electro-acoustic transducer in the single output mode includes a first output rod 31, a pre-tightening bolt 4, a first pre-tightening end cover 51, an excitation coil 6, a magnetic circuit cover plate 7, a base 8, a first pressure sensor 91, a first disc spring 101, a first pad 111, a first magnetic conducting block 121, a second magnetic conducting block 122, a rod 13, a permanent magnet 14, a magnetic yoke 15 and an excitation coil 6. The magnetic yoke 15 can be made of silicon steel sheet.

[0137] As shown in Figure 5 , Figure 6As shown, in the double output mode, the two rods 13 are rigidly connected to the two second output rods 32 respectively, and the two rods are decoupled and do not affect each other. In the double output mode, the two giant magnetostrictive rods drive independent output ends to vibrate axially, two second pressure sensors 92 monitor the prestress received by the two rods respectively, and the independent displacement data of the two rods are collected by the two second displacement sensors 22 at the top respectively, the differentiated material parameters of the two rods are identified, and the performance inconsistency between the two giant magnetostrictive rods is reflected. In the double output mode, different prestresses can be applied to different rods. The electro-acoustic transducer in the double output mode includes the second output rod 32, the pre-tightening bolt 4, the second pre-tightening end cover 52, the excitation coil 6, the magnetic circuit cover plate 7, the base 8, the second pressure sensor 92, the second disc spring 102, the second pad 121, the first magnetic conducting block 121, the second magnetic conducting block 122, the rod 13, the permanent magnet 14, the magnetic yoke 15, and the excitation coil 6.

[0138] As shown in Figure 5 、 Figure 6 , the output module of the electro-acoustic transducer in the double output mode includes the second output rod 32.

[0139] The electro-acoustic transducers in the single output mode and the double output mode have the same excitation driving module. The excitation driving module includes a programmable AC power supply, a capacitor matching board, and a DC power supply, which are used to provide a mixed excitation current of AC and DC. The capacitor matching board in the excitation driving module has a plurality of capacitors, and also includes a plurality of plug-in interfaces and connection lines. The size of the capacitors can be quickly adjusted through the plug-in interfaces to match different working conditions of the test system. The plug-in adjustable capacitor matching board can quickly match the inductive load characteristics of the test system under different working conditions, thereby improving the driving efficiency of the power supply and the test stability of the system. The excitation driving module is electrically connected with the excitation coil, and is used to provide an AC excitation current, or a DC excitation current, or a mixed excitation current of AC and DC. The programmable AC power supply uses an existing AC power supply. The excitation driving module is the power module.

[0140] The signal processing module is used for processing, visualizing and comparing parameters of the collected signals. The signal processing module includes an upper computer, which is electrically connected with the excitation driving module and the signal acquisition module, and is used for processing the collected signals, visualizing the signals, comparing the extracted parameters, and intuitively representing the inconsistency of the rods. The upper computer can process the test data in real time, visualize the test data, extract the parameters of the giant magnetostrictive rods under corresponding working conditions, compare the parameters, and intuitively represent the inconsistency of the rods. The upper computer can be electrically connected with each sensor through an acquisition card.

[0141] The output characteristic test method of the giant magnetostrictive electro-acoustic transducer is realized on the basis of the electro-acoustic transducer output characteristic test system described above. The output characteristic test method runs in the signal processing module.

[0142] The test method of the application discards the assumption of the consistency of the performance of the rods. First, a magnetic circuit model in parallel form is established; second, differentiated dynamic magnetization models are respectively established for the two rods, and the magnetization intensities of the two rods are calculated; finally, the output forces of the two rods are vector-coupled to solve the overall displacement in combination with a nonlinear strain model and a single-degree-of-freedom dynamic equation. The application effectively solves the prediction error problem caused by the performance difference of the rods by combining system measurement with differentiated modeling, significantly improves the prediction accuracy of the output characteristics of the electro-acoustic transducer, and provides reliable basis and theoretical support for the utilization of the giant magnetostrictive material and the performance optimization of the electro-acoustic transducer.

[0143] Specifically, the test method of the application includes the following steps:

[0144] Step 1: Establish a magnetic circuit model in parallel form: according to the input current applied to the series circuit by the excitation driving module and the parameters of the permanent magnet, introduce a magnetic resistance correction factor G M , calculate the effective axial magnetic field intensity H acting on the rod, and the calculation formula is formula Eq47.

[0145] Wherein, the expression of the input current i ac (t) is:

[0146] Formula Eq50: ;

[0147] In combination with formula Eq50, formula Eq48 and formula Eq49, the formula 5 of the input current i ac (t) can be obtained.

[0148] Wherein, B j (t) is the magnetic flux density of the region where the jth rod 13 is located. u(t) can be a direct current voltage or an alternating current voltage or a voltage superimposed by direct current and alternating current. u(t) is the voltage applied to the series circuit by the power module.

[0149] Step 2: Establish a differentiated dynamic magnetization model; for the two physically parallel giant magnetostrictive rods, the assumption of performance consistency is discarded, and independent magnetization models are respectively established, such as the dynamic Jiles-Atherton magnetization model.

[0150] An abnormal loss magnetic field intensity H anom,j and an eddy current loss magnetic field intensity H eddy,j are introduced to correct the effective magnetic field. The specific expression of the Jiles-Atherton magnetization model after the correction of the nonlinear magnetization process includes the above formula Eq41 to formula Eq47, and also includes:

[0151] Formula Eq48: B j =μ0(H+Mj );

[0152] Formula Eq49: ;

[0153] delta is a direction parameter, which ensures that the energy is always lost through dissipation. The parameter delta is introduced M,j to avoid the appearance of non-physical negative magnetic susceptibility phenomenon in the calculation.

[0154] Step 3: Calculate the independent output force; establish a nonlinear magnetostrictive strain model, and calculate the output forces F G,1 and F G,2 of the two rods according to the magnetization intensities M1 and M2 of the two rods respectively. The strain model formula is formula Eq31 and formula Eq32.

[0155] Step 4: Dynamic coupling solution: establish a single degree of freedom dynamic equation containing the load mass, damping and stiffness, and perform vector superposition on the output forces F G,1 and F G,2 corresponding to the two rods respectively as the system driving force, and solve to obtain the overall output displacement x of the electro-acoustic transducer, that is, the dynamic equation:

[0156] ;

[0157] Where M eq , C eq , K eq are the equivalent mass, equivalent damping and equivalent stiffness of the system including the load, and A r is the cross-sectional area of the rod.

[0158] In this embodiment, the current-displacement curves of different rods in static state and the current-displacement curves of different rods in dynamic state are drawn. As shown in Figure 8 , for gradually increasing current in static state, there is inconsistency between the output displacement of rods of the same specification and the relationship between input current, and the performance difference is large. As shown in Figure 9 , in the dynamic state of applying an alternating voltage across the series circuit, there is also obvious inconsistency between the output displacement of rods of the same specification and the relationship between input current. Figure 8 In the formula, B1, B2, …, B8 represent 8 different rods of the same specification. Figure 9 In the formula, B1, B2, …, B6 represent 6 different rods of the same specification.

[0159] As shown in Figure 10 , the displacement-time curve obtained by the output characteristic test method according to the present application is basically consistent with the actual test result, the curve is well matched, and the effectiveness of the output characteristic test method of the present application is confirmed.

[0160] In order to verify the effectiveness of the formula Eq5 of the present application on the input current, the working frequency is set to 100Hz, 300Hz, 600Hz respectively, and at each frequency, the voltage-current relationship curve comparison diagram is shown according to the experimental results, the method of the present application, and the ordinary equivalent circuit model, as shown in Figures 11-13 The experimental results are the voltage-current relationship curve obtained by measuring the input current according to the set input voltage and current sensor, and the curve corresponding to the method of the present application is the voltage-current relationship curve obtained by the input current and the actual measured voltage according to the above formula Eq5 of the present application. Figure 11 Figure 12 Figure 13 It can be seen that at different frequencies, the deviation of the existing ordinary equivalent circuit model (taking the voltage divided by the equivalent impedance of the series circuit as the input current) from the experimental results is more obvious, and the voltage-current relationship curve obtained based on the above formula Eq5 of the present application is closer to the curve of the experimental results, that is, in terms of the closeness to the actual experimental results, it is obviously superior to the voltage-current relationship curve obtained according to the existing ordinary equivalent circuit model.

[0161] Figures 14-17 The current-displacement relationship curve comparison diagram is shown according to the experimental results, the method of the present application, and the existing superposition model when the working frequency is set to 100Hz, 200Hz, 300Hz, 500Hz respectively. The experimental results are the current-displacement relationship curve obtained by measuring the input current according to the current sensor and the output displacement according to the first displacement sensor. The existing superposition model assumes that the material parameters and performance of the two rods are completely consistent, that is, the system is simplified as linear superposition of single rod performance. From Figure 14 Figure 15 Figure 16 Figure 17 It can be seen that the experimental results of the current-displacement relationship curve obtained by using the existing superposition model and by testing the current and displacement are quite different. In contrast, at different frequencies, the current-displacement relationship curve obtained based on the method of the present application is less different from the experimental results, and is obviously superior to the existing superposition model.

[0162] The above are only the preferred embodiments of the present application, and do not limit the present application in any form. Any skilled person in the art can make any simple modification, equivalent change and modification to the above embodiments according to the technical essence of the present application without departing from the scope of the technical solution of the present application.​​​​​

Claims

1. A method for testing the output characteristics of an electroacoustic transducer considering rod material inconsistency, characterized in that, The electroacoustic transducer includes J parallel rods (13), which are magnetostrictive rods; J≥2; each rod (13) has an excitation coil (6) wound around its outer side; the excitation coils (6) are connected in series to form a series circuit; The electroacoustic transducer has a single output mode; when the electroacoustic transducer is in single output mode, the electroacoustic transducer includes a first output rod (31), each rod (13) abuts against the first output rod (31), and the end of the first output rod (31) away from the rod (13) forms the output end of the electroacoustic transducer; on the projection plane perpendicular to the axial direction of the rod (13), the projections of J rods (13) are evenly arranged in the circumferential direction of the projection of the first output rod (31). The method for testing the output characteristics of the electroacoustic transducer includes: Step A: Set the electroacoustic transducer to single output mode, apply the same prestress to each rod (13), and determine the strain of each rod based on the prestress of the rod (13) and the volume magnetization intensity corresponding to each rod, according to the strain model formula. Step B: Based on the strain of each bar obtained in Step A, determine the output force corresponding to each bar; Step C: Based on the prestress on the rod (13) and the output force corresponding to each rod obtained in step B, construct a dynamic equation that reflects the relationship between the output displacement and time of the electroacoustic transducer, thereby obtaining the relationship between the output displacement and time of the electroacoustic transducer in single output mode.

2. The method for testing the output characteristics of an electroacoustic transducer according to claim 1, characterized in that, Each bar (13) has the same specifications; the kinetic equation is: ； Where: M eq C eq K eq These correspond to the equivalent mass, equivalent damping, and equivalent stiffness of the axially vibrating component, respectively; x is the output displacement of the electroacoustic transducer; t is time; σ is the prestress on the rod (13); A r F is the cross-sectional area of ​​the bar (13). G,j The output force corresponding to the j-th rod (13) obtained in step B; j = 1, 2, ..., J; the axial vibration component is the whole structure of the electroacoustic transducer that moves in the axial direction of the rod (13).

3. The method for testing the output characteristics of an electroacoustic transducer according to claim 2, characterized in that, The electroacoustic transducer includes a transducer base; both ends of the rod (13) in the axial direction are fixedly connected to permanent magnets (14). When the electroacoustic transducer is in single-output mode: the electroacoustic transducer further includes a first pre-tightening end cap (51) detachably connected to the transducer base; the first pre-tightening end cap (51) has a first through hole (510) corresponding to the first output rod (31); the first output rod (31) is fixed to the first mounting base (310), and each rod (13) abuts against the first output rod (31) by abutting the end of the first mounting base (310) away from the first output rod (31); the first output rod (31) extends away from the rod (13) in the axial direction of the rod (13) and passes through the first through hole (510); the rod (13) of The end near the first mounting base (310) is connected to the first mounting base (310) in sequence via a permanent magnet (14) and a magnetic guide block; the first pre-tightening end cap (51) abuts against the first mounting base (310) through an annular structure sleeved on the outside of the first output rod (31), thereby applying the same prestress to each rod (13); the annular structure includes a first disc spring (101) and a first pressure sensor (91) arranged in sequence; the magnetic guide block, the rod (13), the permanent magnet (14) fixedly connected to the rod (13), the annular structure, and the first output rod (31) constitute the axial vibration component.

4. The method for testing the output characteristics of an electroacoustic transducer according to claim 2, characterized in that, The formula for the output force corresponding to the j-th bar is: F G,j =A r E H,j l j ; Among them: A r E is the cross-sectional area of ​​the bar (13). H,j Let λ be the Young's modulus of the j-th bar (13); j Let S be the strain of the j-th bar (13) obtained in step A; When σ≤σ s When the strain model formula is: ； When σ>σ s When the strain model formula is: ； Where: λ j Let σ be the strain of the j-th bar. s For the saturated prestress corresponding to bar (13), σ max The maximum stress that the bar (13) can withstand is tanh(2σ / σ). s ) is 2σ / σ s The hyperbolic tangent function, λ s,j M represents the saturation magnetostriction coefficient of the j-th rod (13). j M is the bulk magnetization of the j-th rod (13). s,j Let be the saturation magnetization of the j-th rod (13).

5. The method for testing the output characteristics of an electroacoustic transducer according to claim 4, characterized in that, J is an even number: two permanent magnets (14) corresponding to the rod (13) are fixedly connected to the upper and lower surfaces of the rod (13) respectively; each excitation coil (6) has the same number of turns; for two adjacent excitation coils (6) in the circumferential direction, the N pole of the magnetic field generated by one excitation coil and the N pole of the magnetic field generated by the other excitation coil are located on opposite sides in the height direction; the N poles of two permanent magnets (14) corresponding to the same rod are located on the same side in the height direction; for two adjacent rods (13) in the circumferential direction, the N poles of the permanent magnets (14) corresponding to one rod and the N poles of the permanent magnets (14) corresponding to the other rod are located on opposite sides in the height direction; By combining the following formulas, the bulk magnetization M corresponding to the j-th rod can be determined. j : M an,j =M s,j [nutrition(H e,j / from j )-(from j / H e,j )]; H e,j =H+αr j M j -(H eddy,j +H anom,j ); ar j =a j +9min s,j sM j / 2μ0(M s,j ) 2 ; M j =M rev,j +M irr,j ; M rev,j =c j (M an,j -M irr,j ); dM irr,j / dH=(M an,j -M irr,j ) / [k j δ-αr j (M an,j -M irr,j )]; ； in: M rev,j M is the reversible magnetization of the j-th rod (13). irr,j c is the irreversible magnetization of the j-th rod (13); j M is the reversibility coefficient of the j-th bar (13); an,j H is the hysteresis-free magnetization of the j-th rod (13); H is the effective axial magnetic field strength of the rod (13); k j Let αr be the pinning parameter of the j-th bar (13); j The mean field parameter of the domain coupling after correction for the j-th rod (13); The current flowing through the excitation coil (6) is a function of time t, denoted as the input current i. ac (t); G M B is the magnetoresistive correction factor, N is the number of turns of the excitation coil (6); r L represents the remanent magnetic flux density of the permanent magnet (14); GMM L is the dimension of the bar (13) along its axial direction. PM μ is the dimension of the permanent magnet (14) along the axial direction of the rod (13). GMM Let μ be the relative permeability of the rod (13). PM M is the relative permeability of the permanent magnet (14), μ0 is the permeability of free space; s,j H is the saturation magnetization of the j-th rod (13); e,j The magnetic field strength of the effective field inside the j-th rod (13); as j Let λ be the shape factor of the hysteresis-free magnetization of the j-th rod (13). s,j H represents the saturation magnetostriction coefficient of the j-th rod (13); eddy,j H is the eddy current loss magnetic field strength of the j-th rod (13); anom,j It is the abnormal loss magnetic field strength of the j-th rod (13); α j δ is the average field parameter of the interdomain coupling of the j-th rod (13); δ is the direction parameter; when dH / dt≥0, δ=1; when dH / dt<0, δ=-1.

6. The method for testing the output characteristics of an electroacoustic transducer according to claim 5, characterized in that, The electroacoustic transducer also has multiple output modes; When the electroacoustic transducer is in multi-output mode, the electroacoustic transducer includes a second output rod (32) corresponding to each rod (13). The rod (13) abuts against the corresponding second output rod (32). The end of each second output rod (32) away from the corresponding rod (13) forms one of the output ends of the electroacoustic transducer. Each output end of the electroacoustic transducer is independent of each other. The rod (13) and the corresponding second output rod (32) are coaxially arranged. The steps preceding step A include steps PA1 and PA2; Step PA1: Set the electroacoustic transducer to multi-output mode, apply prestress to each rod (13), and measure the displacement of each second output rod (32) in the axial direction of the rod (13); Step PA2: Based on the prestress of each rod (13) and the displacement of the corresponding second output rod (32) in the axial direction of the rod (13), determine the reversibility coefficient, pinning parameters, saturation magnetization, shape factor of hysteresis-free magnetization, saturation magnetostriction coefficient, eddy current loss magnetic field strength, abnormal loss magnetic field strength, and average field parameters of interdomain coupling for each rod (13), thereby determining the bulk magnetization of each rod.

7. The method for testing the output characteristics of an electroacoustic transducer according to claim 1, characterized in that, The current flowing through the excitation coil (6) is a function of time t, denoted as the input current i. ac (t); The method for testing the output characteristics of the electroacoustic transducer further includes: based on the input current i ac The expression for (t), the relationship between the output displacement and time of the electroacoustic transducer obtained in step C, and the relationship between the input current and the output displacement are obtained.

8. The method for testing the output characteristics of an electroacoustic transducer according to claim 5 or 7, characterized in that, Each rod (13) has the same specifications; J is an even number; two permanent magnets (14) corresponding to the rod (13) are fixedly connected to the upper and lower surfaces of the rod (13) respectively; each excitation coil (6) has the same number of turns; for two adjacent excitation coils (6) in the circumferential direction, the N pole of the magnetic field generated by one excitation coil and the N pole of the magnetic field generated by the other excitation coil are located on opposite sides in the height direction; the N poles of two permanent magnets (14) corresponding to the same rod are located on the same side in the height direction; for two adjacent rods (13) in the circumferential direction, the N poles of the permanent magnets (14) corresponding to one rod and the N poles of the permanent magnets (14) corresponding to the other rod are located on opposite sides in the height direction; The input current i is determined according to the following formula. ac The expression for (t); ； Wherein, the voltage applied across the series circuit is a function of time t, denoted as u(t); R is the equivalent impedance of all excitation coils (6); N is the number of turns of the excitation coil (6); A r Let μ be the cross-sectional area of ​​the rod (13), μ0 be the vacuum permeability; j = 1, 2, ..., J; H is the effective axial magnetic field strength of the rod (13); t is time; k j c is the pinning parameter of the j-th bar (13); j α is the reversibility coefficient of the j-th bar (13); j M represents the mean field parameter of interdomain coupling in the j-th rod (13); j M is the bulk magnetization of the j-th rod (13); an,j H is the hysteresis-free magnetization of the j-th rod (13); e,j δ is the magnetic field strength of the effective field inside the j-th rod (13); δ is the direction parameter; δ M,j It is the magnetization state switching parameter corresponding to the j-th rod (13); when dH / dt≥0, δ=1; when dH / dt<0, δ=-1; when (dH / dt)(M an,j -M j When )≤0, δ M,j =0; when (dH / dt)(M an,j -M j When )>0, δ M,j =1.

9. A test system for the output characteristics of an electroacoustic transducer considering the inconsistency of rod material, characterized in that, include: A computer device or processor configured or programmed to perform the steps of the method for testing the output characteristics of an electroacoustic transducer as described in any one of claims 1-8; A pre-stressing mechanism is used to apply prestress to each bar (13); A power module is used to supply power to the series circuit; When the electroacoustic transducer is in single-output mode, the electroacoustic transducer also includes a first pressure sensor (91) for measuring the prestress on the rod (13).

10. The electroacoustic transducer output characteristic testing system according to claim 9, characterized in that, The electroacoustic transducer includes a transducer base; When the electroacoustic transducer is in single-output mode: the pre-tightening mechanism is a first pre-tightening end cap (51) detachably connected to the transducer base; the first pre-tightening end cap (51) has a first through hole (510) corresponding to the first output rod (31); the first output rod (31) is fixed to the first mounting base (310), and each rod (13) abuts against the first output rod (31) by abutting against the end of the first mounting base (310) away from the first output rod (31); the first output rod (31) extends away from the rod (13) in the axial direction of the rod (13) and passes through the first through hole (510); the first pre-tightening end cap (51) abuts against the first mounting base (310) by a first disc spring (101) sleeved on the outside of the first output rod (31) and a first pressure sensor (91), thereby applying the same prestress to each rod (13); The electroacoustic transducer also has multiple output modes; When the electroacoustic transducer is in multi-output mode: the pre-tightening mechanism is a second pre-tightening end cap (52) detachably connected to the transducer base; the electroacoustic transducer also includes a second output rod (32), a second pressure sensor (92), a second disc spring (102), and a displacement sensor corresponding to the rod (13); the second pre-tightening end cap (52) has a second through hole (520) corresponding to each of the second output rods (32); the displacement sensor is used to measure the displacement of the corresponding second output rod (32) in the axial direction of the rod (13); the second output rod (32) is fixed to the corresponding second mounting base (320), and the rod (13) abuts against the end of the corresponding second mounting base (320) away from the corresponding second output rod (32). Thus, it abuts against the corresponding second output rod (32); the second output rod (32) extends away from the rod (13) in the axial direction of the rod (13) and passes through the corresponding second through hole (520); the second pre-tightening end cap (52) abuts against the second mounting base (320) corresponding to the second output rod (32) through the corresponding second disc spring (102) and the corresponding second pressure sensor (92) sleeved on the outside of each second output rod (32), thereby applying prestress to each rod (13); the end of each second output rod (32) away from the corresponding rod (13) forms one of the output ends of the electroacoustic transducer, and each output end of the electroacoustic transducer is independent of each other; the rod (13) and the corresponding second output rod (32) are coaxially arranged.

Images