CN104977849A - Vessel shaft-rate electric field transformation system and suppression method thereof - Google Patents

Abstract

The invention relates to a vessel shaft-rate electric field transformation system and a suppression method thereof. The vessel-used system for transforming a periodic shaft-rate electric field into a non-periodic shaft-rate electric field comprises a data acquisition module which is used for acquiring angle information of rotation of a vessel rotating shaft; a computing and control module which is used for obtaining a control signal corresponding to the angle information according to the angle information; and a counteracting current generation module which outputs an accurate current value according to the control signal outputted by the computing and control module so as to counteract current generating the shaft-rate electric field. The periodic shaft-rate electric field can be transformed into the non-periodic shaft-rate electric field, intensity of the vessel shaft-rate electric field can be reduced, influence of the vessel shaft-rate electric field can be reduced, the signal characteristic of a remote detection vessel can be weakened, vessel concealing performance can be enhanced and vessel vitality can be enhanced.

Description

A kind of Ship Axle Frequency Electric Field transformation system and suppressing method thereof

Technical field

The present invention relates to a kind of Ship Axle Frequency Electric Field transformation system and suppressing method thereof.

Background technology

The corrosion current on naval vessel and cathodic protection current all can flow through axle system, and as shown in Figure 1, in Fig. 1, the equal spindle of A, B, C, D holds, and M represents turbine, and arrow represents direction of current, and when axle system rotates, its impedance cyclical variation, can produce axle electric field frequently.And in the past in decades, the damping noise reduction technology on naval vessel is fast-developing, it is more and more quieter that naval vessel becomes, and the impact of axle electric field is frequently increasingly serious.Axle frequently fields propagate distance, be easily identified, become significant naval vessel characteristic signal, can be used for ship detection, tracking, location and strike.Russia, American and Britain, Jia Deng state achieve suitable achievement in Ship Axle Frequency Electric Field research, and the research of domestic this respect is almost blank, makes my naval vessel face grave danger, under one's control.

The generation of Ship Axle Frequency Electric Field is because Modern Ships is mostly made up of different metal material, because of electrochemical action, different metal has different electrode potentials in the seawater, particularly can there is higher potential difference (PD) between screw propeller made of copper, pipeline, valve etc. and the ship shell of steel, form corrosion galvanic cell, produce corrosion current.For improving the antiseptic power on naval vessel, naval vessel all can adopt active cathodic protection system.The D.C. high-current that the active cathodic protection system in naval vessel provides and corrosion current acting in conjunction, can impel larger electric current to flow through screw propeller, axle system, naval vessel hull, and form loop through seawater, as shown in Figure 1.When the propeller rotational on naval vessel, the equivalent electrical circuit signal in this loop as shown in Figure 2, in Fig. 2, A, B, C, D all represent the bearing resistance with rotation period change, E represents hull resistance, F represents the seawater resistance with rotation period change, and the contact impedance of axle system bearing can change with rotation period, and then causes shaft current cyclical variation, thus produce the electric field with rotating shaft rotating speed same frequency, i.e. axle electric field frequently.Meanwhile, the seawater impedance between naval vessel impressed current anode and propeller blade also can the generating period change along with the rotation of screw propeller, causes the electric current generation external modulation flowing through screw propeller and axle system, produces with rotating speed and the number of blade product axle electric field frequently that is fundamental frequency.In addition; the electric field that the seawater disturbance that the electric field that the induction field that naval vessel low-frequency current field also comprises harmonic electric field that impressed current cathodic protection electric power system causes, Ship Motion produces, hull leakage current and electromagnetic radiation produce, Ship Motion cause produces; these low-frequency current field can superpose with axle frequency electric field, affect axle Electric Field Characteristics frequently.

According to Maxwell's electromagnetic theory, axle frequently field decay speed is slower, and propagation distance is farther.Therefore, under naval ship water in electric field, axle frequently electric field is more easily detected by enemy's electric field monitoring system, electric field fuse submarine mine etc., and its signal characteristic is more easy to identify, is more easily used to detect naval vessel, follow the tracks of, locate and hit.

At present, more American-European countries ELF (Extremely Low Frequency) electric field adopting axle earthed system to reduce rotary-wing modulation more.The corrosion current on naval vessel and protection current produce axle electric field frequently because rotation axis rotates, ideally, the way of isolation rotation axis can be adopted to eliminate these changes, but the consideration of the other factors such as corrosion for countershaft and screw propeller, and rotating shaft must ground connection.Therefore many countries installation shaft earthed system all aboard ship, this system rotating shaft is connected with shell with collector ring by one group of brush, as shown in Figure 3.Low ESR due to ground brush decreases the fluctuation of bearing impedance, make this axle earthed system can reduce the ELF (Extremely Low Frequency) electric field on naval vessel, but because naval vessel running environment is severe under normal circumstances, be easy to (can be described as and be bound to) between brush and collector ring and fall into dust or greasy dirt, thus result in resistance value increase between brush and collector ring, and then make axle earthed system suppress the usefulness of axle frequency electric field to be lost, and brush and collector ring place are difficult to maintenance.

Summary of the invention

The present invention is intended to solve the problem, provide a kind of Ship Axle Frequency Electric Field transformation system and suppressing method thereof, periodicity axle frequency electric field can be changed into aperiodicity axle electric field frequently by it, reduce the intensity of Ship Axle Frequency Electric Field, reduce the impact of Ship Axle Frequency Electric Field, weaken the signal characteristic on remote probe naval vessel, strengthen the disguise on naval vessel, improve ship survivability, its technical scheme adopted is as follows:

A kind of Ship Axle Frequency Electric Field transformation system, is characterized in that, comprising:

Data acquisition module, its angle information rotated for obtaining naval vessel rotation axis;

Computing and control module, it utilizes the funtcional relationship obtained by modeling to draw the control signal corresponding with angle information for the angle information obtained according to data acquisition module;

Resist current generating module, it comprises controllable constant-current source, and its control signal exported according to computing and control module exports current value accurately, offsets the electric current producing axle frequency electric field, suppresses axle electric field frequently.

On technique scheme basis, described data acquisition module forms primarily of light source generator, light source receiver, processor and scrambler, described light source generator is all connected with processor with light source receiver, and described processor is connected with computing and control module.

Optionally, described scrambler forms primarily of axle sleeve, connecting portion and coding cylinder, described axle sleeve is fixed on naval vessel rotation axis, described axle sleeve is by connecting portion and coding cylinder Joint, described coding cylinder have some annular code channels arranged side by side, every bar code channel by the through hole that light can be allowed to pass through and light cannot through phaeodium composition, described light source generator and light source receiver to be relatively fixed on naval vessel hull and one to be positioned at coding cylinder outside, one to be positioned at coding cylinder inner.

Optionally, described scrambler is primarily of axle sleeve, left connecting portion, right connecting portion and coding cylinder composition, described axle sleeve is fixed on naval vessel rotation axis, described axle sleeve is by left connecting portion and right connecting portion and cylinder Joint of encoding, described coding cylinder have some annular code channels arranged side by side, every bar code channel by the through hole that light can be allowed to pass through and light cannot through phaeodium composition, described light source receiver is fixed on naval vessel hull and to be positioned at coding cylinder outside, described light source generator is fixed on axle sleeve and to be positioned at coding cylinder inner, the projection scope of described light source generator can cover all code channels.

Utilize above-mentioned Ship Axle Frequency Electric Field transformation system to suppress the method for Ship Axle Frequency Electric Field, it is characterized in that, comprise the following steps:

A) sample is obtained, select the actual boats and ships that typically can produce axle frequency electric field, by this naval vessel with the periodicity axle system that frequently electric field changes into aperiodicity axle electric field to be frequently installed on real ship and on real ship installation shaft current monitoring module frequently, real ship is travelled in true waters, data acquisition module is utilized to obtain angle samples { θ }, and utilize axle frequently current monitoring module obtain the axle corresponding with angle information frequently current sample I}, and utilize angle samples and the modeling of axle frequency current sample to obtain they between funtcional relationship I=f (θ);

B) by step a) in the angle that obtains and the funtcional relationship I=f (θ) of axle frequently between electric current input in computing and control module;

C) real ship in the process of moving, the angle information that data acquisition module Real-time Obtaining is instant by angle information transfer in computing and control module, obtain funtcional relationship J=f (θ) during computing and control module utilize step a) and export a size of current control signal corresponding with rotation axis current angular, control to resist current generating module output one and the axle suppression electric current that electric current is reverse frequently.

On technique scheme basis, step a) in also comprise:

Step a1), axle frequently electric field suppresses the modeling of electric current delay time error;

First set up axle frequently electric field suppress current signal model, a usual axle frequently electric field suppresses time series process i (t) of electric current delay value to be formed by the function superposition of M different cycles, can set its functional form as:

$i\left(t\right)=\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)---\left(1\right)$

Wherein, which bearing j represents, j=1 ... M; I _jfor the amplitude of the axle frequency field current signal that a jth bearing causes, ω _jfor the angular frequency of the axle frequency field current signal that a jth bearing causes, θ _jfor the initial phase of the axle frequency field current signal that a jth bearing causes.

To the distortion of (1) formula, obtain linear formula:

$i\left(t\right)=\underset{j=1}{\overset{M}{\mathrm{\Σ}}}[I_j\sin {\mathrm{\θ}}_j\·\cos ({\mathrm{\ω}}_i\·t)+I_i\cos {\mathrm{\θ}}_i\·\sin ({\mathrm{\ω}}_i\·t)]---\left(2\right)$

Then theoretical according to propagation of error, obtain shaft frequently electric field suppress electric current delay time error model with

$\begin{array}{c}d\left(i\left(t\right)\right)=\frac{\∂}{\∂(I_j,{\mathrm{\ω}}_j,{\mathrm{\θ}}_j)}\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\right)\\ =\frac{\∂}{{\∂I}_j}\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\right)\·{\mathrm{dI}}_j+\frac{\∂}{{\∂\mathrm{\ω}}_j}\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_i)\right)\·{\mathrm{d\ω}}_j+\frac{\∂}{{\∂\mathrm{\θ}}_i}\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{I}_i\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_i)\right){\mathrm{d\θ}}_i\\ =\underset{j=1}{\overset{M}{\mathrm{\Σ}}}[\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\·{\mathrm{dI}}_i+I_i\cos ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\·t\·{\mathrm{d\ω}}_j+I_i\cos ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j){\mathrm{d\θ}}_j]\end{array}$

Pass between each periodic term parameter error is:

For a jth specific periodic term in above formula, its periodic term parameter amplitude I _jthe absolute error dI caused _jtransfer coefficient be:

sin(ω _j·t+θ _j)

Frequencies omega _jthe absolute error d ω caused _jtransfer coefficient be:

I _icos(ω _j·t+θ _j)·t

Initial phase θ _jthe absolute error d θ caused _jtransfer coefficient be:

I _icos(ω _j·t+θ _j)

In formula (1) and formula (2), t represents the time, and which bearing j represents, j=1 ... M; I _jfor the amplitude of the axle frequency field current signal that a jth bearing causes, ω _jfor the angular frequency of the axle frequency field current signal that a jth bearing causes, θ _jfor the initial phase of the axle frequency field current signal that a jth bearing causes;

Finally above-mentioned mathematical model is inputed in computing and control module.

On technique scheme basis, step a) in also comprise:

Step a2), axle frequently electric field suppresses the temperature error modeling of electric current:

First, current error is suppressed to carry out modeling with the output of main drive shaft earthed system, the polynomial expression of difference output data fitting is adopted to represent, what Temperature error model described is axle electric field suppression frequently current error variation with temperature rule, suppresses current error to carry out modeling with the output of main drive shaft earthed system in longer temperature range.For getting rid of the impact of other factors, the general polynomial expression of difference output data fitting that adopts represents, Temperature error model is generally expressed as the polynomial expression of temperature t, namely

d _t＝a ₀+a ₁t+a ₂t ²+…+a _mt ^m(3)

In formula, d _tfor temperature error, a ₀, a ₁, a ₂..., a _mfor the coefficient of polynomial mathematical model, each coefficient can be obtained by regretional analysis.In engineering practice, the coefficient of polynomial expression height power item is general all very little, and Temperature error model item number obtains too much, also little to the contribution of compensation precision, can roll up computing cost on the contrary.More common Temperature error model generally only gets two just can meet accuracy requirement, that is:

d _t＝a ₀+a ₁t (4)

Can deriving its regretional analysis, to solve the calculating formula of multinomial coefficient as follows:

${\left[\begin{array}{c}{a}_0\\ a_1\end{array}\right]}_j={\left(X^{T}X\right)}^{-1}{X}^{T}Y---\left(2.2\right)$

Wherein: $X={\left[\begin{array}{cccc}1& 1& ...& 1\\ T& 2T& ...& \mathrm{nT}\end{array}\right]}^{\′},$ Y=[N ₁n ₂n _n] ', T is the temperature interval of sampling, can think T=i, N after sliding-model control _ibe i-th and suppress current error difference output data;

Then above-mentioned mathematical model is inputed in computing and control module.

Tool of the present invention has the following advantages: the intensity reducing Ship Axle Frequency Electric Field, reduce the impact of Ship Axle Frequency Electric Field, weaken the signal characteristic on remote probe naval vessel, strengthen the disguise on naval vessel, improve ship survivability, propose the accurately predicting method suppressing electric current, can compensate the delay time error of axle electric field suppression frequently electric current, can compensate the temperature error of axle electric field suppression frequently electric current, thus more effectively accurately reduce the impact of Ship Axle Frequency Electric Field, the mode of active suppression axle frequency electric current is adopted to compare axle earthing mode, easy to control, affect little by objective factor, easy adjustment.

Accompanying drawing explanation

Fig. 1: Ship's corrosion and protection current loop;

Fig. 2: the schematic equivalent circuit of axle system current return;

Fig. 3: axle earthed system;

Fig. 4: structural representation of the present invention;

Fig. 5: the cross-sectional view of data acquisition module described in embodiment 1;

Fig. 6: the cross-sectional view of scrambler of the present invention;

Fig. 7: the side-looking structural representation (state one) of scrambler described in embodiment 1;

Fig. 8: the side-looking structural representation (state two) of scrambler described in embodiment 1;

Fig. 9: the cross-sectional view of data acquisition module described in embodiment 2;

Embodiment

Below in conjunction with accompanying drawing and example, the invention will be further described:

Through testing in large quantities and analyzing, applicant finds that axle frequency electric field is cyclical variation, cause the axle angle that electric current and naval vessel rotation axis rotate frequently of axle frequency electric field to there is certain corresponding relation.

Embodiment 1

As shown in Figures 4 to 6, a kind of Ship Axle Frequency Electric Field transformation system, is characterized in that, comprising:

Data acquisition module 100, its angle information rotated for obtaining naval vessel rotation axis 21;

Computing and control module 200, it utilizes the funtcional relationship obtained by modeling to draw the control signal corresponding with angle information for the angle information obtained according to data acquisition module 100;

Resist current generating module 300, it comprises controllable constant-current source, and its control signal exported according to computing and control module 200 exports current value accurately, offsets the electric current producing axle frequency electric field, suppresses axle electric field frequently.

Preferably, described data acquisition module 100 forms primarily of light source generator 101, light source receiver 102, processor 103 and scrambler 104, described light source generator 101 is all connected with processor 103 with light source receiver 102, and described processor 103 is connected with computing and control module 200.

Preferably, described scrambler 104 is primarily of axle sleeve 10, connecting portion 11 and coding cylinder 12 form, it should be noted that connecting portion 11 can be support bar (as shown in Figure 7) and also can be supporting disk (as shown in Figure 8) herein, described axle sleeve 10 is fixed on naval vessel rotation axis 21, described axle sleeve 10 is by connecting portion 11 and coding cylinder 12 Joint, described coding cylinder 12 have some annular code channels 13 arranged side by side, every bar code channel 13 by the through hole 14 that light can be allowed to pass through and light cannot through phaeodium 15 form, described light source generator 101 and light source receiver 102 to be relatively fixed on naval vessel hull 20 and one to be positioned at coding cylinder 12 outside, one is positioned at coding cylinder 12 inside.It should be noted that herein, adopt coding cylinder 12 its carry out in the longitudinal direction encode (each bar code channel all gets a through hole 14 or phaeodium 15 forms a digital quantity), because its diameter is from left to right all constant, therefore the width of code channel 13 is without the need to changing (through hole 14 and phaeodium 15 density constant), easy-encode and be easy to read, not easily occur error, the capacity of codified is large simultaneously.

Through hole 14 and phaeodium 15 are arranged on code channel 13 according to certain rules.During work, light is incident upon on coding cylinder 12, coding cylinder 12 rotates with moving object, light through through hole 14 is accepted by light source receiver 102 after slit, the arrangement of light source receiver 102 and code channel one_to_one corresponding, if for the signal that the light source receiver 102 of through hole 14 and phaeodium 15 exports, the former is " 1 ", the latter is " 0 ", when cylinder 12 of encoding is rotated in diverse location, the combination that light source receiver 102 outputs signal reflects the digital quantity of certain rule, represent the angular displacement of coding cylinder 12, this angular displacement can be absolute value (first presetting an initial value relative to initial value) or relative value (relatively last angular displacement), be advisable to take absolute value.

Utilize above-mentioned Ship Axle Frequency Electric Field transformation system to suppress the method for Ship Axle Frequency Electric Field, comprise the following steps:

A) sample is obtained, select the actual boats and ships that typically can produce axle frequency electric field, by this naval vessel with the periodicity axle system that frequently electric field changes into aperiodicity axle electric field to be frequently installed on real ship and on real ship installation shaft current monitoring module frequently, real ship is travelled in true waters, data acquisition module 100 is utilized to obtain angle samples { θ }, and utilize axle frequently current monitoring module obtain the axle corresponding with angle information frequently current sample I}, and utilize angle samples and the modeling of axle frequency current sample to obtain they between funtcional relationship I=f (θ);

B) by step a) in the angle that obtains and the funtcional relationship I=f (θ) of axle frequently between electric current input in computing and control module 200;

C) real ship in the process of moving, the angle information that data acquisition module 100 Real-time Obtaining is instant by angle information transfer in computing and control module 200, obtain funtcional relationship I=f (θ) during computing and control module 200 utilize step a) and export a size of current control signal corresponding with rotation axis current angular, control to resist current generating module 300 and export one and the axle suppression electric current that electric current is reverse frequently.

It should be noted that, delay time error refers to that control system is from reception detection signal, and the suppression current error that the time delays experienced to sending and performing instruction causes, the suppression current error that time delay causes is time dependent herein.When by axle, electric field mechanism of production known axle frequency electric field is mainly rotated by axle system frequently, the cyclical variation of impedance causes, therefore frequently electric field suppresses electric current also corresponding to axle is periodically variable, when there is multiple bearing in Ship Axle system, or multiple contact point is when doing different cyclical variations, then can think that axle electric field suppression frequently current signal model is the superposition of multiple sine function, therefore preferred, step a) in also comprise:

Step a1), axle frequently electric field suppresses the modeling of electric current delay time error;

First set up axle frequently electric field suppress current signal model, a usual axle frequently electric field suppresses time series process i (t) of electric current delay value to be formed by the function superposition of M different cycles, can set its functional form as:

$i\left(t\right)=\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)---\left(1\right)$

Wherein, which bearing j represents, j=1 ... M; I _jfor the amplitude of the axle frequency field current signal that a jth bearing causes, ω _jfor the angular frequency of the axle frequency field current signal that a jth bearing causes, θ _jfor the initial phase of the axle frequency field current signal that a jth bearing causes.

To the distortion of (1) formula, obtain linear formula:

$i\left(t\right)=\underset{j=1}{\overset{M}{\mathrm{\Σ}}}[I_j\sin {\mathrm{\θ}}_j\·\cos ({\mathrm{\ω}}_i\·t)+I_i\cos {\mathrm{\θ}}_i\·\sin ({\mathrm{\ω}}_i\·t)]---\left(2\right)$

Then theoretical according to propagation of error, obtain shaft frequently electric field suppress electric current delay time error model with

$\begin{array}{c}d\left(i\left(t\right)\right)=\frac{\∂}{\∂(I_j,{\mathrm{\ω}}_j,{\mathrm{\θ}}_j)}\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\right)\\ =\frac{\∂}{{\∂I}_j}\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\right)\·{\mathrm{dI}}_j+\frac{\∂}{{\∂\mathrm{\ω}}_j}\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{I}_j\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_i)\right)\·{\mathrm{d\ω}}_j+\frac{\∂}{{\∂\mathrm{\θ}}_i}\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{I}_i\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_i)\right){\mathrm{d\θ}}_i\\ =\underset{j=1}{\overset{M}{\mathrm{\Σ}}}[\sin ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\·{\mathrm{dI}}_i+I_i\cos ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j)\·t\·{\mathrm{d\ω}}_j+I_i\cos ({\mathrm{\ω}}_j\·t+{\mathrm{\θ}}_j){\mathrm{d\θ}}_j]\end{array}$

Pass between each periodic term parameter error is:

For a jth specific periodic term in above formula, its periodic term parameter amplitude I _jthe absolute error dI caused _jtransfer coefficient be:

sin(ω _j·t+θ _j)

Frequencies omega _jthe absolute error d ω caused _jtransfer coefficient be:

I _icos(ω _j·t+θ _j)·t

Initial phase θ _jthe absolute error d θ caused _jtransfer coefficient be:

I _icos(ω _j·t+θ _j)

In formula (1) and formula (2), t represents the time, and which bearing j represents, j=1 ... M; I _jfor the amplitude of the axle frequency field current signal that a jth bearing causes, ω _jfor the angular frequency of the axle frequency field current signal that a jth bearing causes, θ _jfor the initial phase of the axle frequency field current signal that a jth bearing causes;

Finally above-mentioned mathematical model is inputed in computing and control module 200.

It should be noted that herein, due to temperature factor impact widely, the temperature drift of what wherein temperature influence was maximum is electronic circuit.Electronic devices and components are mainly made up of semiconductor, and temperature variation obviously can have influence on the carrier concentration of semiconductor inside, thus affects the operating characteristic of semiconductor devices.Therefore, temperature is an important errors source of axle electric field suppression frequently current error.Therefore preferred, step a) in also comprise:

Step a2), axle frequently electric field suppresses the temperature error modeling of electric current:

First, current error is suppressed to carry out modeling with the output of main drive shaft earthed system, the polynomial expression of difference output data fitting is adopted to represent, what Temperature error model described is axle electric field suppression frequently current error variation with temperature rule, suppresses current error to carry out modeling with the output of main drive shaft earthed system in longer temperature range.For getting rid of the impact of other factors, the general polynomial expression of difference output data fitting that adopts represents, Temperature error model is generally expressed as the polynomial expression of temperature t, namely

d _t＝a ₀+a ₁t+a ₂t ²+…+a _mt ^m(3)

In formula, d _ifor temperature error, a ₀, a ₁, a ₂..., a _mfor the coefficient of polynomial mathematical model, each coefficient can be obtained by regretional analysis.In engineering practice, the coefficient of polynomial expression height power item is general all very little, and Temperature error model item number obtains too much, also little to the contribution of compensation precision, can roll up computing cost on the contrary.More common Temperature error model generally only gets two just can meet accuracy requirement, that is:

d _j＝a ₀+a ₁t (4)

Can deriving its regretional analysis, to solve the calculating formula of multinomial coefficient as follows:

${\left[\begin{array}{c}{a}_0\\ a_1\end{array}\right]}_j={\left(X^{T}X\right)}^{-1}{X}^{T}Y---(2.3)$

Wherein: $X={\left[\begin{array}{cccc}1& 1& ...& 1\\ T& 2T& ...& \mathrm{nT}\end{array}\right]}^{\′},$ Y=[N ₁n ₂n _n] ', T is the temperature interval of sampling, can think T=i, N after sliding-model control _ibe i-th and suppress current error difference output data;

Then above-mentioned mathematical model is inputed in computing and control module 200.

Embodiment 2

As shown in Fig. 4, Fig. 6 and Fig. 9, a kind of Ship Axle Frequency Electric Field transformation system, is characterized in that, comprising:

Data acquisition module 100, its angle information rotated for obtaining naval vessel rotation axis 21;

Computing and control module 200, it utilizes the funtcional relationship obtained by modeling to draw the control signal corresponding with angle information for the angle information obtained according to data acquisition module 100;

Resist current generating module 300, it comprises controllable constant-current source, and its control signal exported according to computing and control module 200 exports current value accurately, offsets the electric current producing axle frequency electric field, suppresses axle electric field frequently.

Preferably, described data acquisition module 100 forms primarily of light source generator 101, light source receiver 102, processor 103 and scrambler 104, described light source generator 101 is all connected with processor 103 with light source receiver 102, and described processor 103 is connected with computing and control module 200.

Preferably, described scrambler 104 is primarily of axle sleeve 10, left connecting portion 11a, right connecting portion 11b and coding cylinder 12 form, described axle sleeve 10 is fixed on naval vessel rotation axis 21, described axle sleeve 10 is by left connecting portion 11a and right connecting portion 11b and coding cylinder 12 Joint, described coding cylinder 12 have some annular code channels 13 arranged side by side, every bar code channel 13 by the through hole 14 that light can be allowed to pass through and light cannot through phaeodium 15 form, described light source receiver 102 is fixed on naval vessel hull 20 and to be positioned at coding cylinder 12 outside, described light source generator 101 is fixed on axle sleeve 10 and to be positioned at coding cylinder 12 inner, the projection scope of described light source generator 101 can cover all code channels 13.

It should be noted that, embodiment 2 is for embodiment 1, and the coding cylinder 12 of embodiment 1 easily occurs error for cantilever position rigidity deficiency herein, and coding cylinder 12 rigidity of embodiment 2 is better, not easily deforms during rotation.

It suppresses the method for axle frequency electric field identical with embodiment 1.

The invention is not restricted to above-mentioned specific embodiment, all any changes of doing based on the present invention or modification all belong to the scope of protection of present invention.

Claims (7)

1. a Ship Axle Frequency Electric Field transformation system, is characterized in that, comprising:

Data acquisition module (100), its angle information rotated for obtaining naval vessel rotation axis (21);

Computing and control module (200), it utilizes the funtcional relationship obtained by modeling to draw the control signal corresponding with angle information for the angle information obtained according to data acquisition module (100);

Resist current generating module (300), it comprises controllable constant-current source, and its control signal exported according to computing and control module (200) exports current value accurately, offsets the electric current producing axle frequency electric field, suppresses axle electric field frequently.

2. a kind of Ship Axle Frequency Electric Field transformation system according to claim 1, it is characterized in that: described data acquisition module (100) forms primarily of light source generator (101), light source receiver (102), processor (103) and scrambler (104), described light source generator (101) is all connected with processor (103) with light source receiver (102), and described processor (103) is connected with computing and control module (200).

3. a kind of Ship Axle Frequency Electric Field transformation system according to claim 2, it is characterized in that: described scrambler (104) is primarily of axle sleeve (10), connecting portion (11) and coding cylinder (12) composition, described axle sleeve (10) is with being connected on naval vessel rotation axis (21), described axle sleeve (10) is by connecting portion (11) and coding cylinder (12) Joint, described coding cylinder (12) have some annular code channels (13) arranged side by side, every bar code channel (13) by the through hole that light can be allowed to pass through (14) and light cannot through phaeodium (15) composition, described light source generator (101) and light source receiver (102) be relatively fixed on naval vessel hull (20) upper and one to be positioned at coding cylinder (12) outside, one is positioned at coding cylinder (12) inside.

4. a kind of Ship Axle Frequency Electric Field transformation system according to claim 1 and 2, it is characterized in that: described scrambler (104) is primarily of axle sleeve (10), left connecting portion (11a), right connecting portion (11b) and coding cylinder (12) composition, described axle sleeve (10) is fixed on naval vessel rotation axis (21), described axle sleeve (10) is by left connecting portion (11a) and right connecting portion (11b) and cylinder (12) Joint of encoding, described coding cylinder (12) have some annular code channels (13) arranged side by side, every bar code channel (13) by the through hole that light can be allowed to pass through (14) and light cannot through phaeodium (15) composition, described light source receiver (102) is fixed on naval vessel hull (20) and goes up and be positioned at coding cylinder (12) outside, described light source generator (101) is fixed on axle sleeve (10) and goes up and be positioned at coding cylinder (12) inside, the projection scope of described light source generator (101) can cover all code channels (13).

5. utilize a kind of Ship Axle Frequency Electric Field transformation system as described in claim 3 or 4 to suppress a method for Ship Axle Frequency Electric Field, it is characterized in that, comprise the following steps:

A) sample is obtained, select the actual boats and ships that typically can produce axle frequency electric field, by this naval vessel with the periodicity axle system that frequently electric field changes into aperiodicity axle electric field to be frequently installed on real ship and on real ship installation shaft current monitoring module frequently, real ship is travelled in true waters, data acquisition module (100) is utilized to obtain angle samples { θ }, and utilize axle frequently current monitoring module obtain the axle corresponding with angle information frequently current sample I}, and utilize angle samples and the modeling of axle frequency current sample to obtain they between funtcional relationship I=f (θ);

B) by step a) in the angle that obtains and the funtcional relationship I=f (θ) of axle frequently between electric current input in computing and control module (200);

C) real ship in the process of moving, the angle information that data acquisition module (100) Real-time Obtaining is instant by angle information transfer in computing and control module (200), obtain funtcional relationship I=f (θ) during computing and control module (200) utilize step a) and export a size of current control signal corresponding with rotation axis current angular, control to resist current generating module (300) output one and the axle suppression electric current that electric current is reverse frequently.

6. the method for suppression Ship Axle Frequency Electric Field according to claim 5, is characterized in that, step a) in also comprise:

Step a1), axle frequently electric field suppresses the modeling of electric current delay time error;

First set up axle frequently electric field suppress current signal model, a usual axle frequently electric field suppresses time series process i (t) of electric current delay value to be formed by the function superposition of M different cycles, can set its functional form as:

Wherein, which bearing j represents, j=1 ... M; I _jfor the amplitude of the axle frequency field current signal that a jth bearing causes, ω _jfor the angular frequency of the axle frequency field current signal that a jth bearing causes, θ _jfor the initial phase of the axle frequency field current signal that a jth bearing causes.

To the distortion of (1) formula, obtain linear formula:

Then theoretical according to propagation of error, obtain shaft frequently electric field suppress electric current delay time error model with

Pass between each periodic term parameter error is:

For a jth specific periodic term in above formula, its periodic term parameter amplitude I _jthe absolute error dI caused _jtransfer coefficient be:

sin(ω _j·t+θ _j)

Frequencies omega _jthe absolute error d ω caused _jtransfer coefficient be:

I _icos(ω _j· ^t+θ _j)·t

Initial phase θ _jthe absolute error d θ caused _jtransfer coefficient be:

I _icos(ω _j·t+θ _j)

In formula (1) and formula (2), t represents the time, and which bearing j represents, j=1 ... M; I _jfor the amplitude of the axle frequency field current signal that a jth bearing causes, ω _jfor the angular frequency of the axle frequency field current signal that a jth bearing causes, θ _jfor the initial phase of the axle frequency field current signal that a jth bearing causes;

Finally above-mentioned mathematical model is inputed in computing and control module (200).

7. the method for the suppression Ship Axle Frequency Electric Field according to claim 5 or 6, is characterized in that, step a) in also comprise:

Step a2), axle frequently electric field suppresses the temperature error modeling of electric current:

First, current error is suppressed to carry out modeling with the output of main drive shaft earthed system, the polynomial expression of difference output data fitting is adopted to represent, what Temperature error model described is axle electric field suppression frequently current error variation with temperature rule, suppresses current error to carry out modeling with the output of main drive shaft earthed system in longer temperature range.For getting rid of the impact of other factors, the general polynomial expression of difference output data fitting that adopts represents, Temperature error model is generally expressed as the polynomial expression of temperature t, namely

d _t＝a ₀+a ₁t+a ₂t ²+…+a _mt ^m(3)

In formula, d _tfor temperature error, a ₀, a ₁, a ₂..., a _mfor the coefficient of polynomial mathematical model, each coefficient can be obtained by regretional analysis.In engineering practice, the coefficient of polynomial expression height power item is general all very little, and Temperature error model item number obtains too much, also little to the contribution of compensation precision, can roll up computing cost on the contrary.More common Temperature error model generally only gets two just can meet accuracy requirement, that is:

d _t＝a ₀+a ₁t (4)

Can deriving its regretional analysis, to solve the calculating formula of multinomial coefficient as follows:

Wherein: y=[N ₁n ₂n _n] ', T is the temperature interval of sampling, can think T=i, N after sliding-model control _ibe i-th and suppress current error difference output data;

Then above-mentioned mathematical model is inputed in computing and control module (200).