瑞典专利SE1050351A1 A decoder

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AbstractThe present invention reïates to a method and an encoder for determining one or moreparameters, each parameter being related to a type of vibratiou for the encoder. The encoder ís mount-ed on an axís and arranged to detect rotary movement of the axis. Fig. 2 34
公开号:SE1050351A1
申请号:SE1050351
申请日:2010-04-09
公开日:2011-10-10
发明作者:Fredrik Gustafsson
申请人:Leine & Linde Ab；
IPC主号:

专利说明:

An encoderTechnical ﬁeld The present invention relates to a method and an encoder and in particular to a method and an encoder for determining at least one parameter related to a type of vibration for the encoder.
Background A rotary encoder is an important sensor commonly used in closed loop velocity control andpositioning applications within industrial applications, for example in plants for paper or steelmaking in which the rotary encoder may be arranged to detect rotary movement of a machineshaft. ln general, rotary encoders comprise a detector part which detects rotary motion andgenerates a signal corresponding to the detected angular position change. Different values,such as angular Velocity 'and number of revolutions may be derived from the signal. Therotary encoders further comprise means, such as a hearing for attaching the rotary encoder toa shait of a machine whose movement is to be detected as well as means for attaching a casing of the rotary encoder to a casing of the machine.
There are several different types of rotary encoders, for example optoelectrical encoders asdescribed in EP 1480344. This type of encoder includes an encoding disc that has an opticaliyreadable pattem. There are also other types of rotary encoders based on other measurementprinciples. These encoders include for example magnetic encoders, inductive encoders, capacitive encoder.
One problem related to rotary encoders is that the rotary encoders are used in environmentswhich cause different types of wear to the rotary encoder. Due to the wear that the rotaryencoder is snbjected to the overall condition of the rotary encoder degrades-which in turn maylead to malfunctioning of the rotary encoder.
Another factor which may inﬂuence negatively on the overall condition of the rotary encoderis the quality of the installation of the rotary encoder, for instance the alignment of the rotary encoder When the rotary encoder is installed in the machine.
A faulty rotary encoder could lead to unscheduled stops of machines or pI-ants for service or replacement of parts. This is disadvantageous since it leads to costly drops in production.
It is known in the art to monitor the condition of rotary encoders. The optical rotary encoderdescribed in EPl480344 comprises a circuit that provides a warning signal when the opticaldisc of the rotary encoder is contaminated. A user is then informed that the encoder needsservice. However, although proven useful, the rotary encoder described in EP1480344 doesnot provide the user with information about the quality of the installation of the rotary encoder or about the environment in which the encoder is iocated.
Summary Thus, it is an object of the present invention to provide an improved encoder and a method inan encoder for determining one or more parameters where each parameter is related to a type of vibration for the encoder.
This object is according to the present invention achieved by finding different expressionsthat describe accelerations in different directions at different points of the encoder. Theseexpressions are used to calculate parameters related to the different types of vibration that the encoder is exposed to.
According to a first aspect, the present invention relates to a method for determiníng one ormore parameters, each pararneter being related to a type of vibration for an encoder mountedon an axis and arranged to detect rotary movement of the axis, and whercin an element ﬁxedat the encoder prevents the encoder from rotating with the axis; the method comprising thesteps of: generating one or more signals, each signal being a response to an acceleration in adirection in a point of the encoder; determining one or more ﬁequency spectrums related tothe one or more signals; ﬁtting one or more expressions related to the one or more signalsbased on the one or more frequency spectrums, where each expression describes anacceleration related to the one or more direction and the one or more points of the encoder;and determining one or more parameters from the one or more expressions, where each parameter is related to a type of vibration for the encoder. l0 According to a second aspect, the present invention relates to an encoder for determining oneor more parameters, each parameters being related to a type of vibration for an encodermounted on an axis and arranged detect rotary movement of the axis, and wherein an elementﬁxed at the encoder prevents the encoder from rotatíng with the axis; the encoder comprises at least one accelerometer for generating one or more signals, each signal being a response toan acceleration in a direction in a point of the encoder. The encoder further comprisesprocessing means for deterrnining one or more frequency spectrurns related to the one or moresignals. The processing means being further conﬁgured to ñt one or more expressions relatedto the one or more signals based on the one or more frequency spectrums, where eachexpression describes an acceleration related to the one or more direction and the one or morepoints of the encoder. The processing means being yet further conﬁgured for determining oneor more parameters from the one or more expressions, where each pararneter is related to a type of vibration for the encoder.
An advantage with embodiments of the present invention is that by detennining parametersrelated to different types of vibration for the encoder a longer lifetime of the encoder can be achieved since the encoder can be installed with a minimum amount of vibrations.
IO Brief description of the drawiugs Figure 1 schematicaily iilustrates an encoder according to an embodiment of the present invention.
Figure 2 is a ﬂow diagram of a method according to an exemplaiy embodimcnt of the present invention.
Figure 3 schematically illustrates an eneoder according to an embodirnent of the present invention.
Figure 5 illustrates a relation between a first coordinate system and a second coordinate system as a ﬁinction of time.
Figure 6 illustrates a relation between a first coordinate system a second coordinate system and a third coordinate system as a function of time.
Figure 7 shows a plot of x against y for a position at the encoder where x”=40, y"=0, h=50and e=0.01.
Figure 8 shows a plot of x against y for a position at the encoder where x”=-40, y”=0, h=50and e=0.01.
Figure 9 shows a plot of x against y for a position at the encoder where x°°ﬂ0, y”=40, h=50and e=0.01 Figure I0 shows a plot of x against y for a position at the encoder where x”=0, y“=-40, h=50and e=0.01 Figure 11 shows a plot of the acceleration in the x-direction against the acceleration in the y- direotion in the first coordinate system where x”=0, y”=0, h=50 and e=0.01 Figure 12 shows a plot of the acceleration in the x-direction against the acceleration in the y- direction in the first coordinate system where x”=40, y”=0, h=50 and e=0.01.
Figure 13 shows a plot of the acceleration in the x-direction against the acceleration in the y- direction in the first coordinate system where x”=-40, y” '=0, h=50 and e=0.01.
Figure 14 shows a plot of the acceleration in the x-direction against the acceleration in the y- direetion in the first coorciinate system where x”=0, y”=40, h=50 and e=0.01.
Figure 15 shows a plot of the acceleration in the x-direction against the acceleration in the y- direction in the ﬁrst coordinate system where x” '=0, y”=-40, h=50 and e=0.01.
Figure 16 shows a graph iilustrating the measurement error of an encoder mounted on an eccentric axis with e=0.01 and h=50.
Figure 17 illustrates the symmetry axis y” 1800 of the encoder.
Figure 18 iliustrates a wobbling motion of the encoder when the symmetry axis y” 1800 of the encoder is not parallel with the syrnrnetry axis y 1810 of the rotation.
Figure 19 iilustrates two layers, z=z0 and z=0, with the coordinate systems X1", yl ” resp.x2”, y2”.
Figure 20 illustrates a plot of motions in the x-direction against the y-direction and in the z- direction during one revolution where x”=40, y”=O, g=25, h=50, e@=0.01 and z0=1O0.
Figure 21 illustrates a plot of accelerations in the x-direction against the y-direction and in the z-direction during one revolution where x”=40, y”=0, g=25, h=50, eU=0.01 and z0=100.
Figure 22 illustrates a plot of accelerations in the x-direction against the y-direetion and in the z-direction during one revolution where h=50, e0=0.01, Z0=l00, x°°=40, y"=0 and g=-43.
Detailed description Referring to figure 1 there is iliustrated exernplary embodiments of the encoder 10 fordetermining one or more parameters, each parameter being related to a type of vibration forthe encoder 10. The encoder is mounted on an axis 20 and arranged to detect rotaiy movement of the axis 20.
The encoder 10 may be exposed to many different types of vibrations. One type of vibratíonthat may arise is a vibration that occnrs if the axis 20 is out of line. Another type of vibrationthat may arise is a vibration that occurs if the axis 20 is wobbling. Yet another type ofvibration that may arise is a vibration that occurs if there is a play in an element 40 thatprevents the encoder from rotating With the axis_ The element 40 may for instance be a torqueann 40. The encoder 10 may also be exposed to a vibration that occurs from different types ofimpacts or vibratíons from a motor (not shown). These different types of vibrations are onlyexamples of types of vibrations that the encoder 10 may be exposed to. The encoder 10 mayalso be exposed to other types of vibrations. The encoder 10 may also be exposed to these different types of vibrations above simultaneously.
The different types of vibrations cause different types of wear to the encoder 10. Asmentionecl above, due to the wear that the encoder 10 is subjected to the overall condition ofthe encoder 10 degrades which in turn may lead to malfunctioning of the encoder 10. Some types of vibrations also cause measurement errors from the encoder 10.
According to an idea of the invention it is possible to find different expressions that describeaccelerations in different directions at different points of the encoder 10. These expressionscan according to the present invention be used to calculate parameters related to the differenttypes of vibration that the encoder is exposed to. How the expressions are used to calculatethe different parameters will be described further down. First some examples of how differentexpressions are found for different possible types of vibrations that the encoder may beexposed to. These expressions are only examples of expression that can be found foraccelerations at different points of the encoder 10. These expressions differ if for instance other parameters are used to describe a motion of the axis 20. An example of another factor that affects the expressions is which means that is used to prevent the encoder from rotating.
For example a ﬂexible coupiing gives a different set of expressions.
In exemplary embodiments of the encoder 10 the element 40 is a torque arm 40 ﬁxed at theencoder 10 that prevents the encoder 10 from rotating with the axis 20. In these exemplaryembodiments of the invention a length of the torque arm 40 is L. The distance from a point 50 where the torque arm 40 is ﬁxed to a centre 90 of the rotary encoder is h.
Eccentric axis As mentíoned above one possible type of vibratíon that the encoder 10 may be exposed to is avibration that arises in a case when the axís 20 is out of line. For this type of vibration it ispossible to ﬁnd different expressions for accelerations at different points of the encoder 10.Below an example will be given of how expressions for accelerations in different directions atdifferent points of the encoder may be found in a case when the axis 20 is out of line. As can be seen in figure 1 the axis has an eccentricity error which is e 21.
A first coordinate system (x, y) 70 in a plane parallel with the encoder 10 has its centre oforigin in a mean centre 80 of the axis 20 during a revolution. A second coordinate system (x',y') 100 has its centre of origin in the encoder 10. The encoder 10 also has its centre of originin a third coordinate system (x”, y”) 11 in the piane, but the third coordinate system 11 isturned so that its negative x-axis passes a point 50 where the torque ann is fixed in the encoder.
An expression which describes a position at the encoder as a function of time is sought. Theexpression that is sought is the expression that describes coordinates in the third coordinatesystem 11 expressed in coordinates in the first coordinate system 70 as a function of time t.
First a relation between the first coordinate system 70 and the second coordinate system 100 is sought. This relation may according to embodiments of the invention be expressed as: (I) (x, y) áxwecos cut, y'+esin an) ; where a) is the angular frequency of the axis.
Figure 5 shows the relation between the ﬁrst coordinate system 70 and the second coordinate system 100 as a function of time t. It is reasonable to assume that a movement of the point 50 where the torque arm 40 is fixed in the encoder 10 is liner since of (tig. 1) can be considered to be small. Fig. 5 illustrates how the point 90 moves in a circle around the origin of centre inthe coordinate system 70 at radius e. Axes in the coordinate system 100 are always parallel tothe axes of 70.
Referring to figure 6 it is possible to express a position in the second coordinate system 100 as a function of coordinates in the third coordinate system 11 as: (x',y'} =(x"cos ço - y"sin ça,x"sin go + y"cos ga)where d -l-QCOSQJÉ . e _sm = -sin mt and eos =i” h Q h Actually also ga can be considered to be small (e< during the differentiation. As can be seen in figure 6, a is given from the cosine theorem: h: = a: -i-ez -Zaecosür-mt) => a = -ecoswt+wlh2 -ez sina art which yields2cosçø =1i1-e_2sin2 mthand u e: ' 2 ne 'x=x ï-íz-sin air-y šsinwtﬂacosætne ' H ez ' I 'y=x ísmwt+y l-íz-sm mr+es1na>r rf where (x , y") are the coordinates of a point at the accelerometer in the third coordinatesystem.
Consider a first example where x”=0 and y”=0. A plot (not shown) of x against y would givea circle around origin of coordinates with the radius e. In another example x”=40, y"= ,h=50 and e=0.01. Figure 7 illustrates this example. As can be seen in figure 7 a movement inthis case is amplified in the y-direction. Consider yet another example where x”=- 40, y”=0, h=50 and e=0.01. Figure 8 illustrates this example. As can be seen in ﬁgure 8 a movement in this case is reduced in the y-direction. Figure 9 illustrates yet another example where x”=O,y”=40, h=50 and eﬂ0.01. Another example is illustrated in figure 10 where x”=0, y”=-40,h=50 and e=0.01.
An acceleration for a point at the acceïerometer 60 as a function of time is given by dzx _, e“aJ2sin22wt eZ _ 2 -m ezarzcos2art e: . 2 -ma -x ---«----_ l-íz-sin ant -----í l--I-Fsan art + “=m=_ 4m ß New sin art - ewa cos for +P day H e“'aJ2sin22aJr e: . 2 -m e2cu2cos2ax ez _ 2 -ma = =y -_----_1--lí-2s1n aut ----í l-z-ïsin air + 4h“ hz sin an' - em: sin an' xll The expressions are unnecessarily complicated, but they can be seen as a series expansion in e/h (e/h<<1). A línear approximation in e/h gives sufﬁcient accuracy: 2new sin an! - eaJz cos an' æ=y 2 Hﬁx sin arr - ewz sin art Consider an example where x”=Û, y”=0, e*=0.01 and h=50. In this example w=2* ï rad/s. A plot of the acceleration in the x-direction and the acceleration in the y-direction in the ﬁrstcoordinate system is shown in figure 11. Another example where x”=40, y”=0, h=50 ande=0.01 is illustrated in figure 12. As can be seen in figure 12 a movement in this case isenhanced in the y-direction. Figure 13 illustrates yet another example where x°°=-40, y"= ,h=50 and e=0.01.
As can be seen in ﬁgmre 13 a movement in this case is damped in the y-direction. Figure 14illusn-ates yet another example where x”=0, y' '=40, h=50 and e=0.0I. Yet another exampleis illustrated in figure 15 where x”=O, y”ß-40, h=50 and e=0.01.
Measurement errors of the encoder as a function of time The error in the measurement of the encoder is the angle ga and is given from. e . e _sinçmzsinax :mwzsmat Figure 16 shows a graph illustrating the measurement error of the encoder. The curve isapproximately harmoníc with one period per revolution. An amplitude of the curve is approximately e/h*l80/Tt in rnechanical degrees. In an example with e=0.01 and h=50 the amplitude will be 0.0l2° and for a rotary encoder with a resolution of 5000 pulses per revolution (ppr) it corresponds to 60 electrical degrees (° el), i.e. one 6th of a period.
A wobbling axis Another possible type of vibratíon that the encoder may be exposed to is a vibration thatarises in a case when the axis 20 is wobblirig. For this type of vibration it is possible to findother expressions for accelerations at different points of the encoder 10. An example of howexpressions may be found for accelerations, in different directions at different points of the encoder in a case when the axis 20 is wobbling is given below.
Position as a function of time for a wobbling axis Referring to figure 17 the wobbling is created if the symrnetry axis y” 1800 of the encoder isnot parallel with the syrnrnetfry axis y 1810 of the rotation (see figure 18). The motion of the encoder 10 is three dimensional and rather complex, therefore some simpliﬁcations are made.
First it is considered that the movement of the point 50 where the torque ann 40 is ﬁxed in the encoder can be considered to be linear analogously to of being small in the eccentric axis case.
In the z-ciirection the turning in the x”y”-piane is disregarded. This turning corresponds tothe error in the angular measurement. If the encoder is doing a wobbling motion withoutrotatíng around its own axis, an arbitrary point in the encoder, Will move in the z-direction according to: Az .e y-./(x")2 + (y")2 X(t) oc y, y << 1, X is an unspeeiﬁed function of time; The dorninating contribution to the motion is thus linear in y, the angle between the axis1810 and the encoder 1800 of ﬁg. 18. Note that the motion is independent from the value ofz”. It is possible to show that the turning in the x”y”-plane that was neglected above connibutes with a second order tenn in 'y, which is the reason it can be considered small.
Intuitively it can be viewed in the following way, with the help of ﬁg. 18. Let the encoder rotate a small angle å, caused by the small angle çß. The distance that a point in the encoderwill move is proportional to ö and in the z~direction the movement will be proportional toyö, Which is much smaller than 7. Az oc yâ << yBy forming thin layers of the encoder at different positions in the z-direction and then look at the Iayers separately the problem isreduced from one problem in three dimensions to a multiple of problems in two dimensions.The idea is to start in the layer where the torque arm 40 is ﬁxed. In this layer or plane z isequal to Zg l700. For the motion in the plane where z=z0 one can make the simpliﬁcation thatthe x”, y” ïpiane is parallel with the x, y-plane and that the z"-axis is parallel with the z-axis but out of line with the eccentricity e0=e(z0). The results ﬁ^om the case with an eccentzric axis can then be used. For an arbitrary layer it is valid that the eccentricity is, e = eo i.zu This means that the tenns in the equations of motion corresponding to a translation should be scaled in a corresponding way. Those terms are the ones that do not contain the variables x” or y". We call them çø-independent. Figure 19 illustrates two layers, z=zu and z=O, with thecoordinate systems xl”yl“ resp. x2”y2”. The angle çß is the same for the two layers, sincethe encoder is rigid. This means that the fp-dependent terms of the equations of motion, i.e. those containing x” or y' ', should not be scaled at all.
An interesting plane is the plane where a circuit board is located, r-"zo-g. In this plane it is now possible to express the coordinates of a point in an arbitrary z-plane as a function of time. ll lO The coordinates may be expressed as: Zo “gzu x_xll llel '- -y hsinait+ eocoswt zo- e _ .y=x"-9-s1nmt+y"+ ge stnæth Û Zo Fzo-g-í-“cosrwfﬂßi oo* +o»">*O The expression for z is given from ﬁgure 18 and also that æt=0when a projection of arotation axis in the xy-piane coincides with the x-axis (See figure 19, where e(z) is thatprojection). The angle çó is also found in figure 17 and only affects “a phase” for the motion (in relation to phases for x- and y-coordinates) Consider an example where h=50, e@=0.01 and z@=100. In this example x"=40, y”=0 and925. A plot of motions in the x-direction, the y-direction and in the z-direction for this example is shown in figure 20.
The accelerations in x, y and z-directions are given from a second derivative of the expression for the positions.dax em: . z -a,=:2=y"-°¿-s1nwt- ° geoaﬁzcoswtdt h zud* ewz _ z - .ny: f=-x" ° sincut- ° geowasinmtdt h zudzz eoaf 2 dtz 2,, COSÜPIIHÜ) (X")2 +(y")2 Note that as zo grows large the expressions above become the same as in the case with aneccentric axis without wobble.
Consider an example where h=50, e0=0.01 and 2:0=100. In this example x”=40, y"=0 and g=25. A plot of accelerations in the x-direction, y-direction and in the z-direction are shown for this example in figure 21 12 In another example h=50, e0=0.01, Z0=100, x”=40, y”=0 and g=-43. A plot of accelerationsin the x-direction, in the y-direction and in the z-direction for this example is shown in figure22.
The error in angular measurement as a function of time is similar to before. __ ef, _ __, eo .smço - -h-sm mt :> (p -ﬂz-sin cor Direct acceleration Yet another possible type of vibration that the encoder may be exposed to is a vibration thatarises ﬁorn different types of impacts or vibrations from a motor. For this type of vihration itis possible to ﬁnd other expressions for aecelerations at different points of the encoder 10. Anexample of how expressions for accelerations, in different directions at different points of the encoder, is given below.
To the theoretical accelerations that the encoder may be exposed to because of for instance aneccentric axis or a wobbling axis may thus other accelerations be added. We denominate those other aecelerations direct acceierations š(t). The expressions for the acceierations in the different directions may now be written as: 2 ra .a, = y"e° smwt-(eo - ;-g)w2 cos cat + sx(r).___ neüwz ' _ __ 2 ' 9ay - x ih sincaz (en ;g)co srnwt+sy(t) () a; = yrøz cos(wt+ç5) (x")2 +(y")2 +s__(t) Where the quantity e-° has been replaced by 7.
ZOAs mentioned above it is according to the present invention possible to determine different parameters related to the different types of vibrations that the encoder 10 may be exposed to. 13 l0 Parameters that may be of interest to determine with the present ínvention are for instance run out 2* eo and an angle of the axis y = í.Cl Referring back to figure 1 which shows exemplary embodirnents of the encoder 10 according to the present invention. The encoder 10 comprises at least one accelerometer 61, 62 for generating one or more signals si, , siz ...si I! _ each signal si, , si; ...siubeing a response to acceleration in a direction in a point 60, 63 of the encoder 10.
First are exemplary embodiments of the encoder 10 that comprise one accelerometer 61 thatmeasures acceleration in one direction (not shown) described. In these exernplaryembodirnents of the encoder 10 the accelerometer 61 generates one signal si, which is aresponse to acceleration in one direction in a point 60 of the encoder 10. The accelerations inthe x, y and z-directions can be described using equation (9). In these exemplazy embodiments of the encoder 10 it is assumed that the direct acceleration s; for the axis 20 is not harmonic with one period per revolution.
Note that the acceierations in the x- and y-directions mostly depend on e., and 7, and that the z-direction mostly depends on 7. The accelerations that are generated from an eccentric axis 20 or a wobbling axis 20 are also harmonic with one period per revolution of the axis 20.
In exernplary embodiments of the encoder 10 eo and y are used to describe a motion of the g axis 20. When using en and 'y to describe the motion of the axis 20 it is advantageous to measure the acceleration in the x-y-plane or in the z-direction. If other parameters were usedto describe the motion of the axis 20 it could also be advantageous to measure the accelerationin other directions. The present invention is therefore not Iirnited to measuring theacceleration in the x-y-plane or in the z-direction. These directions only constitute exemplary ernbodiments of the encoder 10.
Exarnples of how eo and 'y may be calculated in exemplary embodiments where a singleaccelerometer 60 is used will now be given. The parameters on, 0:2, and oc; are scale factors used to express the acceleration in the actual direction of measurement in the coordinates of the coordinate system 11. The expression for an acceleration a; can be written as: 14 al = friade-o, m) + Hidden, m) + war, (7,1) + S10) Assume that 'y is approximately zero. If 'y can not be considered small the acceleration should instead be measured in the z-direction. The acceleration can now be expressed as: al =alax -f-aflay +st :N11 =e0k sín(cot+ó')+s, (100) where tancï = 5-I Assurne that the direct acceleration s1 is not harmonic with one cycle per revolution for the axis 20.
The encoder 10 further comprises processing means 65 which receives the signal si, . Theprocessing means 65 are conﬁgured for determining a frequency spectrum Fm related to thesignal si! _ The processing means 65 are yet further conﬁgured to ﬁt the sinus tenn in theexpression 100 to the frequency spectrum Fan for the sígnalsq. An amplitude Am for a frequency component F, in the frequency spectrum Fm which corresponds to the first harmonic for the axis 20 is determined by the processing means 65. The processing means 65then fits the sinus tenn in the expression 100 to the signal stl based on the amplitude for the frequency component F, in the frequency spectrum Fsn. The processing means 65 thereby determine en as:ef, = - Am (101) The direct acceleration may then be determined by the processing means 65 as: s, = si! - eﬂk sin(wt + å) IS In other exemplary embodiments of the encoder 10 the accelerometer 61 instead measures the acceleration in the z-direction. In these exemplary embodiments of the encoder 10 0:1 and oc; close to zero and oc; is close to 1. The acceleration a; may be expressed as: a! = ozaaz + sl = aaywz cos(aJt + góhixﬂ + y' 'Z + s, = yic cos(mt + çi) + s, (102) Where k is a known constant Assume that the direct acceieration s, is not harmcnic with one period per revolution for theaxis 20. In these exemplary embodirnents the processing means 65 also determines afrequency spectrum Fsﬂ related to the signal sz; . An amplitude Am for a frequency component F,, which corresponds to a cycle of once per revolution, in the frequency spectmm Fan is determined by the processing means 65. The processing means 65 then fits the co sinus tennin the expression 102 to the signal si! based on the amplitude Am. The processing means 65 thereby determine yas: 1=-A 1037 k m ( ) The direct acceleration may then be detenníned by the processing means 65 as:sl = sit - ykcos(a1t+ gå) Now exemplary ernbodiments of the encoder 10, that comprise one accelerometer 61 thatmeasures acceleration a; and a; in two directions (not shown), will be described. In theseexernplary ernbodiments of the encoder 10 the accelerometer 61 generates two signals sil andsi: which are responses to accelerations a; and a; in two directions in the point 60 of the encoder 10. The accelerations a, and a; can be written as: a! :alax (eqsyst)+a2ay(e0sïvt)+a3a;(yzt)+si(t)a: =a-iaxßetwiﬁf)'H-ïsay-(eovïsf)+asaz(}'if)+sz(f) {a, = (eoc, + yc,)sin art + (ene, + ;c_,)cos wt + yes cos(mt + gi) + s,a, = (ena, + yc,)sin an' + (e,,c, + yc,,)cos mt + pen, cos(wt + 45) + s, a, = k, sinßcot + 5,) + s,a, = k, sin(a>t + 5,) + s, (104, 105)where c., c2,...c|0 are known constants and kl, kg, (51 and ö; are known functions of eg and y.
In these exemplary embodiments the processing means 65 are configured to determine frequency spectrums Fm and F55; related to each of the signals si, and si, respectively.
The processing means 65 then ﬁts the sinus terrn in the expressions 104 and 105 to the firstharmonic of the signal si, and si., respectively, based on the frequency spectrums for thesignals. Amplitudes Am; and Arn; for frequency components in the frequency spectrums FS”and F59, which corresponds to the first harmonic for the axis 20 is determined for si, and si,by the processing means 65. The processing means 65 thereby determine eo and y by solving the equation system: {k1(@0,7)=-4"f1kzleosy) z Am: The direct accelerations s, and s; may be considered as remaining parts of the signals si, and siz. The direct accelerations s, and s; can be detezmined by the processing means 65 as: {s, = si, -~ k, sin(mt + 5,)s, = si, - k, sin(rot + 6,) Other exemplary embodirnents of the encoder 10 comprise one accelerometer 61 thatmeasures acceleration al, a; and a; in three directions (not shown). In these exemplary ernbodiments of the encoder 10 the accelerometer 61 generates three signals si, , si, and si, which are responses to accelerations al, a; and a; in three directions (not shown) in the point 60 of the encoder 10. The accelerations al, a; and a; may be written as: 17 ai =araxiensyst)'Fazfß-(eovïit)+aaaz(y=t)+sl(ï) az :a-iai-(euﬂf-tyi'asaﬂeosyvt)+aﬁa:(7:f)+32(t)=> a! :aâaaleﬂiyvt)+aSaJIeOIJ/vt)+aâlaz(yat)+sﬁ(r) a, = (eoc, +yc1)sin wr+(eoc, +yc4)cos wt-I-ycs cos(øt+çﬁ)+sl a, = (ene, + pe, )sin ær +(e°c8 + ya, )cos an' + yen cos(wt + på) +sz :>a, = (eocl, + yen )sin an' + (eocu + ycH)cos w! + yet, cos(wt + gå) +s, a, = k, sin(wt+ó',)+s,a, = k: sin(cut +å2)+s2 a, =lc,sin(wt+ó',)+s3 (106, m7, '08 where, cl, c2,. _ _ .. ..c15 are known constants and khkbkbö 1,62 and ö; are known functions of en and 7/ In these exemplary ernbodiments the processing means 65 are conﬁgured to determinefrequency spectrums Fm, Fm and Fsi; related to each of the signals sit, sg and si, respectively.
The processing means 65 then ﬁts the sinus term in the expressions 106, 107 and 108 to thesignals sil , så and si, respectively based on the ﬁequency spectrums Fm, Fm and FSB for thesignals. Amplitudes Anu, Am; and Am; for frequency components Ffsil, Fm; and Fm; in thefrequency spectmms FS,- 1, F sm and Fm which corresponds to the ﬁrst harmonic for the axis 20 is determined for siï , sig and si; by the processing means 65.
The processing means 65 then determines en and y by finding a solution to the over detennined equation system 109. The processing means may for instance use the method of least squares to ﬁnd a solution to the system 109. k1(2u, )=fím1kz (emï) = Am: k3(e0vï)=Am3 (109) 18 The direct accelerations s., s; and s; may be considered as the remaining parts of the signalssil, si; and sig. The direct accelerations sl, s; and s; can be detennined by the processing means 65 as: s, = si, - k,(e,,,y)sin(wt 4-5,)s, = si, - k,(e,,,y)sin(æ: +52)s, = si, - Ic3(e,,,y)sin(a:t +53) Yet other exemplary ernbodirnents of the encoder 10 comprise two accelerometers 61 and 62 that each measures acceleration in one direction respectively. The accelerorneter 61 measuresacceleration af" and the accelerometer 62 measures acceleration af”. The upper indexdenotes that the accelerations are measured in different positions of the encoder 10.
In these cxemplary embodiments of the encoder 10 the accelerometer 61 generates the signal sif” which is a response to acceleration af" in a direction (not shown) in the point 60 of the encoder 10. The accelerorneter 62 generates the signal sif” which is a response to acceleration af” in a direction (not shown) in the point 63 of the encoder 10. In exemplary embodiments of the encoder 10 the accelerometers 62 and 63 measure the accelerations in a same direction (not shown). In these exernplary embodiments the processing means mayanalyse a differential signal which is a difference between the signals stf” andsif”. Inexemplary embodirnents where the accelerometers 61 and 62 measure the accelerations in the same direction the accelerations af" and af” may be written as. (2) al” = ﬂﬁﬂíher mi) +0f2ﬂ§”(er,,r,r) + 0302” (int) +S.(I)ai = amg) (en, y,t) + a2aff)(ec,,y,t) + tx3af2) (yqt) -I- s, (t) If the equations for af” and af” are subtracted from each other the direct acceleration s, (t) disappears and an equation with two unknown parameters is left.
Consider an exemplary embodiment where 011 and/or oc; are close to 1 and of; is close to 0. In these exemplary embodiments the accelerations af” and af” are measured in a plane parallel with the xy-plane. In these exemplary embodiments "y is considered small. 19 The difference between the accelerations can be expressed as: alm -rzlm = enksilﬂwt + (109) where k and ß are known constants. Note that the direct accelerations s, (t) are cancelled out.
In these exemplaiy embodirnents the processing means 65 are conﬁgured to determine a frequency spectrums E; for a differential signal .sid where the differential signal is adifference between sifn andsifz). The processing means 65 then fits the sinus term in theexpression 109 to the differential signal sid based on the frequency spectrurn Fd for the signal.
An amplitude Am; for a frequency components Fn; in the frequency spectrums Fd which corresponds to the first harrnonic is determined for sid by the processing means 65.
The processing means 65 then determines eg as 1en =-*Am1 kThe direct acceleration s, (t) can be deterrnined by the processing means 65 as:s, (t) = stf" - e0csin(wt + å) where c and ö are known constants.
In other exemplary embodirnents of the encoder X0 that comprise two accelerometers 61 and 62 the accelerations all” and alm are measured along an axis parallel with the z-axis. In theseexemplary embodirnents ot; and (X2 are close to 0 and 04 3 is close to 1. The differencebetween the accelerations can be expressed as: af" -af" = k,y(cos(cot + çSÜU- cos(øt + 415m» = kysin(wt + ß) (110) where k; , k and ß are known constants.
In these exemplary ernbodíments the processing means 65 are also conﬁgured to determine afrequency spectrum Fd for a differential signal si, which is a difference between sf" and stf”.The processing means 65 then ﬁts the sinus term in the expression 110 to the differentialsignal si, based on the frequency spectrum Fd for the signal. An amplitude Am; for a ﬁequcncy component Fm in the frequency spectrum Fd which corresponds to the ﬁrst harmonic is determined for sid by the processing means 65.
The processing means 65 then determines 'y as:1 * Än= - 1l' k mThe direct acceleration S10) can be determined by the processing means 65 as: s, (t) = sifl) - yccos(aJt + aim)where c is a known constant. In other exemplary embodiments the direct acceleration may bedeterrnined by the processing means 65 ﬁ'om the generalized expression: s1(t) = stf" - ycl sín(cot + å) Where c1 and 5 are known constants.Other exemplary ernbodiments of the encoder 10 comprise two accelerometers 61 and 62 thateach measures acceleration in two directions respectively. The accelerometer 61 measures accelerations af” , af” and the accelerometer 62 measures accelerations af” , af” . The upper index denotes that the accelerations are measured in different positions of the encoder 10. Inthese exempíary embodiments of the encoder 10 the accelerometer 61 generates the signals sif” and stf” which are responses to accelerations af” and af” in two directions (not: shown) in the point 60 of the encoder 10. The accelerometer 62 generates the signals stf” , sifzlwhich are responses to accelerations af” , af” in two directions (not shown) in the point 63 of the encoder 10. In exemplary embodíments of the encoder 10 the accelerometers 62 and 63measure the accelerations in the same directions (not shown). In these exemplary embodiments the processing means 65 may analyse differential signals which are a difference between the signals stf", stf” , and stf” , siffirespectively. In exemplary embodirnents where 21 the accelerometers 61 and 62 measure the accelerations in the same directions the accelerations all” mig", af” and af) may be expressed as. af” = alafiﬁeo, y,t) + azaf) (eo, y,t) + cigaf) (y,t) + s, (t) då” = waffketizf) ++ataideﬂf)Hm m_ ma: -amx af) (eo, jgt) + asajfKeo, y,t) + aﬁaíl) (y,t) + s2(t) = a4af)(e0, y,t) -t-asaiz) (en, y,r) + czóaf) (y,t) +s2 (t) The signals stf" , stå", stf” and sig” may be analysed differentially. If the equations for therespective direction are subtracted from each other the direct acceleratíons s,(t), s2(t)disappear and a system with two equations and two unknown parameters is left. Bothcharacteristic parameters eo and y can then be determined. The difference between the accelerations in the same direction can be expressed as: F - ef” = k, sina» + ßl) <1>_ m: -az az k2sm(wt+ß2) (HLHZ) where kl, kg, ß 1 and ß; are known functions of eﬂ and y.
In these exeinplary embodiments the processing means 65 are conﬁgured to determine frequency spectrurns Fm and Fd; for each of the differential signals si' d, and sin, si n., is adifference between Sif” and sill”. si” is a difference between sig) and sig). The processingmeans 65 then ﬁts the sinus terrn in the expression 111 to the differential signal sid, based onthe frequency spectrum Fd; for the signalsiü. An amplitude Amdl for a frequency components Fm in the frequency spectrurns Fm which corresponds to the first harmonic is detennined for sin by the processing means 65. The processing means 65 also ﬁts the sinus term in theexpression 112 to the differential signal sin based on the frequency spectrum Fd; for thesignal sin. An amplitude Amd; for a frequency components Fm; in the frequency spectrums Fd; which corresponds the first harmonic is deterrnined for sin by the processing means 65. 22 The processing means 65 then determines en and y by solving the equation system: {k1(eo» 7) = Amark: (en: V) = Amra The direct acceleration s, (t) and s, (t) can be determined by the processing means 65 as: {s, (t) = stf) - c, sin(a>t + 5,) s, (t) = stf) - c, sin(a)t + 52) where c|, eg, 51, ö; are known functions of en and y.
Other exemplary embodirnents of the encoder 10 cornprise two accelerometers 61 and 62 that each measures acceleration in three directions respectively. The accelerometer 61 measuresaccelerations af), ag) and af), the accelerorneter 62 measures accelerations alu), af) andaf). The upper index denotes that the accelerations are measured in different positions of theencoder 10. In these exernplary ernbodirnents of the encoder 10 the accelerometer 61generates the signals stf), sig" and stå" which are responses to accelerations al” af) and 1 I af) in three directions (not shown) in the point 60 of the encoder 10. The accelerometer 62generates the signals stim, stf) and stf) which are responses to accelerations alla), af) and af) in three directions (not shown) in the point 63 of the encoder 10. In exemplary embodiments of the encoder 10 the accelerometers 62 and 63 measure the accelerations in the same directions (not shown). In these exemplary embodiments the processing means may analyse differential signals which are a difference between the signals stf), sifz) , and sig),stf) and stf) , stf) respectively. In exemplary embodiments where the accelerometers 61 and62 measure the accelerations in the same directions the accelerations af" , ag), af) , afz) , af) and af) may be expressed as. 23 af” = and” (ed, 7,t) + again (ed, y,t) +a,a§')(;f,t) +s, (t) af” = alaff) (ed, yJ) +adaf)(e0,y,t) +cz,a§2”( y, i) +s, (t)af) = adaf)(ed,y,t) +a5a§,“(e0, y,t) -i-adaf) (7,t) +sd(r)af) = adaf) (en , y,t) + asaff) (ed , y, i) + again (y, t) + s, (t) “in zavainæqsfat) 'fagaš-næosyst)+asailj(yvt)+sa(t) af) = adaff) (eo, y, t) + again (eo , y, t) + adašz) (y, t) + s3(t) The signals sifn, sig), Sif), sida), sifiand sida) may be analysed differentially. If theequations for the respective direction are subtracted from each other the direct accelerations sd(t), sd(t)and s,(z) disappear and a system with two equations and two unknownparameters is left. Both characteristic parameters en and 7 can then be determined. The difference between the accelerations in the respective direction can be expressed as: af” - af” = k, sin(mt + ßl) ef” - al” = kd sin(wt + ßd)ap) _d§u = kssiddddfs, 53) p (111, 112, i 13) where kl, kg, kg, ß, , ßd and ß, are known functions of eo and 7.
In these exemplary embodiments the processing means 65 are conﬁgured to determine frequency spectrums F41, Fd; and Fd; for each of the differential signals sidl, si d! and sid, A signal sid, is a difference between sifn and Sif”. A signal sid: is a difference between sig) and sign, and a signal sid, is a difference between the signals siš” and sida). The processingmeans 65 then fits the sinus tenn in the expression 111 to the differential signal sid] based on the frequency spectrum Fd; for the signal. An ampiitude Amd; for a frequency component Fm; in the frequency specn-nm Fd; which corresponds the ﬁrst harmonic is determined for si d, by the processing means 65. The processing means 65 also ñts the sinus terrn in the expression 112 to the differential signal .sidd based on the frequency spectrum Fd; for the signal sidd. An amplitude Amd; for a frequency component Fm in the frequency spectrum Fd; which corresponds to the first harmonic is determined for sidd by the processing means 65. The processing means 65 also fits the sinus term in the expression 113 to the differential signai 24 sin., based on the frequency spectnim Fd; for the signal sid, An amplitude Amd; for a frequency component Fm in the ﬁequency spectrum Fd; which corresponds to the ﬁrst harrnonic is determined for sid, by the processing means 65. The processing means 65 then determines en and y by ﬁnding a solution to the equation system: kr (em 7) = Amark: (eo = f) 2 Amdzk: (en: f) f" Amar The direct accelerations s,(t) , s,(t) and s, (t) can be determíned by the processing means 65 ESI S160: arma) “cr Sinai +61)3,0) qzgkn-.gsinaz +5,)SJÛ) =aiu(f) 'Cs ÜÜÜ! +53) where el, eg, c3, å, å, and 53 are known functions of eo and y.
Other exemplary embodiments of the encoder 10 comprise two accelerometers that eachmeasures accelerations in three directions respectively. In these exemplary embodiments theaccelerations are measured along the base vectors in a cylindrical coordinate system, definedby:x = pcosgåy = psinaZ = ZFig. 3 illustrates these exemplary embodiments of the encoder 10. The accelerometer 61 measures accelerations a aä, and aü. The accelerometer 62 measures accelerations a am p3> p! I and aﬂ. In these exemplary embodirnents of the encoder 10 the accelerometer 61 generates the signals sipp 51,, and sig, which are responses to accelerationsa ap, and az, along the .vä 'base vectors in the point 60 of the eneoder 10. The accelerometer 62 generates the signals sim, sid, and síz, which are responses to accelerations a ap, and ad along the base P1' vectors in the point 63 of the encoder 10.
In the exemplary ernbodiments illustrated in ﬁg. 3 the accelerometers 61 and 62 are placed ata same radius 300 and at a distance of a quarter of a tum. An advantage with these positions is that the amplitude of the differential signals in the xy-plane becomes independent of gå .
Another advantage compared to other positions is that all three differential signals can be usedand that they all have the same order of magnitude in response to the wobbling axis and the eccentricity of the axis. Yet another advantage is that gi only inﬂuences the differential signal in the z-direction and that it is only the phase that is affected.
This means that the only customer speciﬁc parameters that are needed to calculate en and 7 is the pararneter h, the distance from the centre 90 of the rotary encoder to the point 50 where the torque arm 40 is attached to the encoder.
In these exemplar-y embodiments the processing means 65 may also analyse differential signals. In exemplary embodirnents the processing means 65 analyses a differential signal sid,which is a difference between the signals sip, and si ,,, a differential signal sin which is adifference between the signals sid, and sipa, and a differential signal sin., which is a difference between the signals siz, and sin. ln these exemplary embodiments the accelerations for the differential signals can be expressed as: e°m2p sin mt + å(t)h ap, +12” ='- erøzp .aﬂ-ap, =- “h smcot+5(t) az, -ag = Jíywzpsinﬁzii ﬂrhâ)(114,11s,11s) In these exemplary embodíments the processing means 65 are also configured to detenninefrequency spectrums Fdl, Fd; and F43 for each of the differential signals sim, sid, and sin.,The processing means 65 then fits the sinus terrn in the expression 114 to the differentialsignal sig, based on the frequency spectrum Fd; for the signal. An amplitude Amd; for aﬁequency components Fm in the frequency spectrums Fm which corresponds the ﬁrst harmonic is determined for sid, by the processing means 65. The processing means 65 also 26 ﬁts the sinus term in the expression 115 to the differential signal si d, based on the ﬁequencyspectrum Fd; for the signal sin. An amplitude Am; for a ﬁequency component Fm in thefrequency specnum Fü which corresponds to the ﬁrst harrnonic is detcrrnined for sid, by the processing means 65. The processing means 65 also fits the sinns term in the expression 116 to the differential signal si d, based on the frequency specirum Fd; for the signal siß. An amplitude Amd; for a ﬁequency component Fm; in the ﬁequency spectrum Fd; which corresponds to the first harmonic is deterrnined for sid, by the processing means 65.
The processing means 65 then detennines eo and 71 by solving the equation system Am, =enk, w,Am, = eok, where k, = k, = hp, k, =JíwzpAm: :ïka In these exemplary embodiments the method of least squares yields: _ Am, +Am2 _ Alrå,30 _ 2,6, 7 " k, The direct accelerations s p, (t), s,,,(t) and s,(t) can be detennined by the processing means 65 by using all known parameters in equation 117 andcompare with the signals from the accelerometers. The accelerations generated by theeccennic and wobbling axis can then be snbtracted and the processing means can perform further analysis of the direct acceleratíons. sp, (t) = sip, + (e, - j-gyfrf' cos(a1t - çﬂ)eomzph s,,, (t) = sid, -i- sin cat - (e, - yg)aJ2 sin(t'ot -çt5,) s=(r) = sig, - ywzpcosßot + 95,) (117) where sp, =-s,,2 and sd, =sp2The direct accelerations can be written in the generalized forrn: sp, (t) = sip, - c, sin(aJt + ß,)s,, (t) = sig - c, sin(a1t + ßz)s; (t) = sig, - c., sin(cnt + ßa) where 27 ="(eu_ïg)wz 2 2 zc; = -JFiQ-(f-ii) + ((e° - 7g)a:2)+ 2%2(e0 - yg)w2 cosçå, hGﬁrwzpn'Ãbïﬁﬁ_ 0 om eÉp+(e0-;g)cosçál20ß, =arctan a _(e°_ g)sln ä* +;Ip+(9s'}3)°°5¶51 a' om %+(eo-7g)cos45l

权利要求:
Claims (10)
[1] 1. I. A method for determining one or more parameters, each parameters being related to a type of vibration for an encoder (10) mounted on an axis (20) and arranged to detectrotary movement of said axis (20), and wherein an element 40 ﬁxed at said encoder(10) prevents said encoder (10) from rotating with said axis (20); the methodcompiising the steps of:- generating (S200) one or more signals, each signal being a response to anacceleration in a direction in a point of said encoder;- deterrnining (S205) one or more frequency spectrums reïated to said one or moresignals;- ﬁtting (S210) one or more expressions related to said one or more signals basedon said one or more frequency spectrums, where each expression describes anacceleration related to said one or more direction and said one or more points ofthe encoder; and- deterrnining (S215) one or more parameters from said one or more expressions, where each parameter is related to a type of vibration for said encoder.
[2] 2. The method according to ciaim 1, wherein the step of determining (S205) one or morefrequency spectrums comprising detennining the frequency spectrum for each of saidone or more signals, and wherein the step of ﬁtting (S210) comprising ﬁtting anexpression to each of said one or more signals based on each of one or more saidfrequency spectra, where each expressiou describes said acceleration in said direction in said point of the encoder.
[3] 3. A method according to claim 2, wherein said method, after said step of determining,comprises the further step of; I- subtractíng each of said vibratíon using said respective one or more parametersfrom each of said respective signal, thereby obtaining a direct acceleration in each of said respective direction for said encoder. 31 l0
[4] 4. The method according to claim l, wherein in the step of deterrnining (S205) one or more frequency spectrums each frequency spectrum is determined for a differentialsignal, where said differential signal is a difference between a first signal being aresponse to a first acceleration in a first direction in a first point of said encoder and asecond signal being a response to a second acceleration in said first direction in asecond point of said encoder; and wherein in the step of fitting (S210), an expressionis ﬁtted to each of said differential signals, where each expression describes adifference between said first acceleration in said first direction in said first point ofsaid encoder and said second acceleration in said first direction in said second point of said encoder.
[5] 5. A method according to claim 4, wherein said method, after said step of determining,coinprises the further step of;- subtracting each of said vibration using said respective one or more parametersﬁrom each of said respective signal, tliereby obtaining a direct acceleration in each of said respective direction for said encoder.
[6] 6. . An encoder (10) for determining one or more parameters, each parameters being related to a type of vibration for an encoder (10) mounted on an axis (20) and arrangedto detect rotary movement of said axis (20), and wherein an element (40) fixed at saidencoder (10) prevents said encoder (10) from rotating with said axis (20); the encodercomprises: at least one accelerometer (61, 62) for generating one or more signals, eachsignal being a response to an acceleration in a direction in a point of said encoder;processing means (65) for determining one or more frequency spectrums related tosaid one or more signals; said processing means (65) being further configured tofitting one or more expressions related to said one or more signals based on said oneor more frequency spectrurris, where each expression describes an acceleration relatedto said one or more direction and said one or rnore points of the encoder (10); saidprocessing means (65) being yet further configured for determining one or moreparameters from said one or more expressions, where each parameter is related to a type of vibratioii for said encoder. 32
[7] 7. . An encoder (10) according to claim 6, wherein said processing means (65) is further conﬁgured for determining the frequency spectrum for each of said one or moresignals and for ﬁtting an expression to each of said one or more signals based on eachof one or more said spectra, where each expression describes said acceleration in said direction in said point of the encoder.
[8] 8. An encoder (10) according to claitn 7, wherein said processing means (65) is furtherconfigured for:- subtracting each of said vibration using said respective one or more parametersﬁom each of said respective signal, thereby obtaining a direct acceleration in each of said respective direction for said encoder.
[9] 9. . A11 encoder (10) according to claim 7, wherein said processing means (65) is further configured for determining said one or more speclrums for a differential signal wheresaid differential signal is a difference between a first signal being a response to a firstacceleration in a ﬁrst direction in a first point of said encoder (10) and a second signalbeing a response to a second acceleration in said first direction in a second point ofsaid encoder; and where said processing means (65) is yet further conﬁgures for ﬁttingan expression to each of said differential signals, where each expression describes adifference between said ﬁrst acceleration in said first direction in said first point ofsaid encoder and said second acceleration in said first direction in said second point of said encoder.
[10] 10. An encoder (10) according to claim 9, wherein said processing means (65) is further configured for:- subtracting each of said vibration using said respective one or more parametersfrom each of said respective signal, thereby obtaining a direct acceleration in each of said respective direction for said encoder. 33

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同族专利:

公开号 | 公开日

EP2375221A2|2011-10-12|

EP2375221A3|2014-05-28|

EP2375221B1|2017-03-29|

SE534939C2|2012-02-21|

US8459117B2|2013-06-11|

US20110247415A1|2011-10-13|

引用文献:

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

US5253531A|1992-04-10|1993-10-19|Walker Dana A|System and method for monitoring torsional vibrations and operating parameters of rotating shafts|

US5511422A|1993-04-09|1996-04-30|Monitoring Technology Corporation|Method and apparatus for analyzing and detecting faults in bearings and other rotating components that slip|

SE514067C2|1997-06-03|2000-12-18|Leine & Linde Ab|Procedure for determining a state in a sensor, as well as a sensor with state for assessment|

US6424928B1|2000-06-15|2002-07-23|Eim Company, Inc.|Absolute position detector interpreting abnormal states|

US7184930B2|2002-08-30|2007-02-27|Nsk Ltd.|Method and device for monitoring status of mechanical equipment and abnormality diagnosing device|

JP4235425B2|2002-09-20|2009-03-11|Ｈｏｙａ株式会社|Photointerrupter position adjustment mechanism|

US6889553B2|2003-07-16|2005-05-10|Pcb Piezotronics Inc.|Method and apparatus for vibration sensing and analysis|

CA2649647C|2006-04-21|2014-06-17|Flowserve Management Company|Rotary encoder frequency analysis|

DE102008030201A1|2007-07-25|2009-01-29|Dr. Johannes Heidenhain Gmbh|Encoder and method for its operation|

EP2159547A3|2008-08-30|2014-06-11|Walter Mehnert|Sensor component for a rotary encoder and rotary encoder equipped with such a sensor component|DE102017216666A1|2017-09-20|2019-03-21|Dr. Johannes Heidenhain Gmbh|Position measuring device and method for operating a position measuring device|

法律状态:
2018-12-04| NUG| Patent has lapsed|

优先权:

申请号 | 申请日 | 专利标题

SE1050351A|SE534939C2|2010-04-09|2010-04-09|Method and apparatus for determining parameters related to types of vibration for a decoder mounted on a shaft|SE1050351A| SE534939C2|2010-04-09|2010-04-09|Method and apparatus for determining parameters related to types of vibration for a decoder mounted on a shaft|

EP11161083.8A| EP2375221B1|2010-04-09|2011-04-05|Encoder and condition monitoring thereof|

US13/083,965| US8459117B2|2010-04-09|2011-04-11|Method and encoder|

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