CN102003975A - Rotary encoder with built-in self-test - Google Patents
Rotary encoder with built-in self-test Download PDFInfo
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- CN102003975A CN102003975A CN2010102890334A CN201010289033A CN102003975A CN 102003975 A CN102003975 A CN 102003975A CN 2010102890334 A CN2010102890334 A CN 2010102890334A CN 201010289033 A CN201010289033 A CN 201010289033A CN 102003975 A CN102003975 A CN 102003975A
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Abstract
The invention relates to a rotary encoder which contains redundancy and fault-tolerant position detection and utilizes the built-in self-test capability. The rotary encoder is used in various rotary devices containing the valve actuator to generate speed data. The rotary encoder is used to diagnose the problems of the valve actuator and the applications of the other rotary devices; and paticularly the rotary encoder can execute frequency analysis to the data of speed, position, torque, thrust or vibration and the rotary encoder provides the speed or position data of the valve.
Description
The application is that (the China national application number is 200680055069.8 for the PCT patented claim in China national stage that enters of submitting on April 21st, 2006, international application no is PCT/US2006/015174, denomination of invention " rotary encoder with built-in self-test ") divide an application.
Technical field
The present invention relates generally to the analysis of valve actuator and position of rotation scrambler, and relates more specifically to utilize built-in self-test that valve actuator and position of rotation scrambler are carried out frequency analysis.
Background technology
In many application, need the position of the turning axle of measurement whirligig.Yet whirligig usually is complicated and has inaccessible part.And whirligig usually is integrated in the specific industrial process, wherein stops cost that this process keeps in repair whirligig usually considerably beyond the cost of whirligig.For example, rotary valve usually is vital for industrial process, and the maintenance of some parts of valve need make this process stop.Existence is for accurately discerning turning axle and by this turning axle drove such as the needs of the position of the object of valve rod.The needs that also have identification such as any wearing terrain in the whirligig of valve, so that carry out preventative maintenance when being scheduled to shut down, thereby or so that the operation whirligig keeps this device to operate up to predetermined shutdown next time.Existence is for the needs of the device of the seriousness of the problem in the position that can determine turning axle and identification the whirligig that turning axle connected and position.
A method of diagnosis whirligig is to adopt frequency analysis.Can utilize Fourier transform (FT) algorithm to come the analysis cycle data, so that data are become frequency domain from spatial transform.Trial is that motorized valve is used Fourier transform, comprises measuring the electric current that flows to motor, and motor data is used Fourier transform, uses peak value in the frequency spectrum to diagnose problem in the power train of valve actuator then.Yet this method is the rotational speed of measurement axis not, also the position of uncertain turning axle.The current of electric measurement mechanism is not integrated in the device that can determine the turning axle position yet.
A kind of method of measuring the position of rotary part relates to rotary encoder.Rotary encoder comprises incremental encoder and absolute encoder.Incremental encoder is used for the rotation change of measurement axis.Basic incremental encoder comprises the dish that has substantial radial setting-out (painted line).As long as photodiode or other sensor detect setting-out and just produce electric pulse.Computing machine or other processor are followed the trail of the position of pulse with definite this dish, and determine the position of the axle that this dish is attached.Utilize incremental encoder, if computer circuit breaking, then positional information will be lost when power recovery.The previous incremental encoder that is used for valve actuator comprises speed pickup, but speed pickup and the data that produced and be not used in and carry out frequency analysis.
Absolute encoder does not need power supply to keep positional information.Absolute encoder produces each different angle that unique numerical code is used for turning axle.Absolute encoder can be single the wheel, and it has the complex pattern that is worked on the wheel.The single wheel is attached on the reference axis, and many different positions, angle can be discerned by the pattern of taking turns at this.Yet, this situation that axle only experiences the single rotation that is only applicable to of taking turns.
Another form of absolute encoder is utilized a plurality of the wheel, and it has the concentric ring on each is taken turns, and wherein each ring provides the position data of 1 bit.Position and number of revolutions that a plurality of forms of taking turns allow measured beam warp to go through repeatedly rotation and still follow the trail of axle.Exist more wheel to allow to follow the trail of the more rotation of multiaxis or the more multiposition of definite single rotation.Yet the pleiotaxy absolute encoder is usually fragile and reliability is relatively poor.Need reliable and can produce the pleiotaxy absolute encoder of the speed data that be used for frequency analysis by operation.
A trial that addresses this problem is to utilize 6 wheels or 7 wheels.Each is taken turns provides 3 Bit datas.Yet, only produce 2 bit Gray codes as position data via the v bit process.This has increased the reliability of absolute encoder.Yet, do not use repetition sensor (duplicate sensor).In addition, speed pickup is not integrated in the absolute encoder, and does not produce speed data and be used for frequency analysis.
Summary of the invention
One embodiment of the present of invention comprise the rotary encoder that is used for whirligig.Rotary encoder comprises one or more code wheels, and each code wheel in one or more code wheels comprises at least one encoded segment, and these encoded segment can be operated with the position to whirligig and be encoded.Also comprise at least one two group sensor, it can be operated to monitor at least one encoded segment.
Another embodiment of the present invention comprises valve actuator, and valve actuator comprises absolute encoder and is suitable for driving the power train of absolute encoder.Absolute encoder comprises at least one scrambler dish, can operate to read a plurality of sensors of at least one scrambler dish, can operate to produce the speed pickup of speed data, be used at least one repetition sensor of each sensor of a plurality of sensors and speed pickup.
Another embodiment of the present invention comprises the method for analyzing the valve actuator that comprises sensor.This method comprises from sensor generation data and to these data carries out frequency-domain analysis.
Specific embodiment of the present invention comprises the method for the whirligig that analysis is rotated between two position limits.This method comprises the axle that the position of rotation scrambler operationally is attached to whirligig, and wherein the position of rotation scrambler comprises speed indicator.This method comprises to be utilized speed pickup generation speed data and this speed data is carried out frequency analysis.
Consider detailed description hereinafter in conjunction with the drawings, feature of the present invention, advantage and alternative aspect will be apparent for those skilled in the art.
Description of drawings
Though instructions as summary, when read in conjunction with the accompanying drawings, can be easier to definite advantage of the present invention by following description of the present invention with claims of specifically pointing out and advocating clearly to be considered to content of the present invention, in the accompanying drawings:
Fig. 1 shows the wheel of an embodiment of rotary encoder;
Fig. 2 shows the assembling form fully of the embodiment of Fig. 1;
Fig. 3 shows the part assembling form of the embodiment of Fig. 1;
Fig. 4 shows the top view of the embodiment of Fig. 3;
Fig. 5 shows the wheel of the specific embodiment of rotary encoder;
Fig. 6 shows the representational no problem diagnosis in frequency domain;
Fig. 7 shows the representational diagnosis that goes wrong in frequency domain;
Fig. 8 shows the data resolution that utilizes 128 samples;
Fig. 9 shows data are being carried out the data that Fourier transform (FT) is used before in Fig. 8;
Figure 10 shows the data resolution that utilizes 256 samples;
Figure 11 shows and data are being carried out the data of using before the FT in Figure 10;
Figure 12 shows the data resolution that utilizes 512 samples;
Figure 13 shows and data are being carried out the data of using before the FT in Figure 12;
Figure 14 shows the data resolution that utilizes 1024 samples;
Figure 15 is the form of the accuracy of indication some embodiment of the present invention;
Figure 16 is the example with the frequency domain data of 26 rotations of per minute (rpm) acquisition;
Figure 17 is another example with the frequency domain data of 26rpm acquisition;
Figure 18 is the example with the frequency domain data of 18rpm acquisition; And
Figure 19 is another example with the frequency domain data of 18rpm acquisition.
Embodiment
The present invention can be used for any valve actuator or other whirligig, such as the device that rotates between the two positions.Specific embodiment utilization of the present invention has the rotary encoder of integrated speed pickup.Speed pickup can be operated to produce speed data and be used for frequency analysis.The present invention also can use the sensor of another type that can produce the data that can be transformed into frequency domain.And frequency analysis can be used for diagnosing any problem of valve actuator or other whirligig.In one embodiment, rotary encoder is to have the right absolute encoder of repetition sensor.
In the accompanying drawings, similar Reference numeral is represented similar element.Fig. 1 shows an embodiment of rotary encoder of the present invention.The specific embodiment of rotary encoder 1 expression absolute encoder.Do not exist such as the term " wheel " of " input ", " sequential " or qualifiers such as " codings " or " a plurality of wheel " applicable to wheel for inputting 10, timing wheel 20 and code wheel 30 to 110.Phrase " code wheel " or " a plurality of code wheel " are applicable to code wheel 30 to 110.
Bottom erecting frame 130 is fastened on the base plate 120 via bolt 132.Bolt 132 also can be rivet, screw, anchor clamps, clip, bonding agent, pad, snap fit connection or any other coupling arrangement as known in the art.Bolt 132 also can be positioned over any position.For example, when bolt 132 was anchor clamps, bottom erecting frame 130 may extend into the edge of base plate 120, and bolt 132 can be positioned this edge.Perhaps, when bolt 132 was bonding agent, bonding agent can launch on any surface of the bottom erecting frame 130 that contacts with base plate 120.
Base plate 120 can comprise Semiconductor substrate, wherein can be integrated each other such as the electrical equipment of processor 150 and sensor 160.Connection processing device 150 is not illustrated with the circuit of sensor 160.Yet, in circuit being integrated into base plate 120, circuit can be positioned base plate 120 outsides.For example, can in base plate 120, hole with corresponding with the input end and the output terminal of the input end of sensor 160 and output terminal and processor 150.Insulated wire can interconnect between sensor 160 and processor 150.In addition, ifs circuit is positioned base plate 120 outsides, base plate erecting frame 130 can be merged in the base plate 120.
In addition, rotary encoder 1 is not limited to any given shape.Rotary encoder 1 can be circle, rectangle or specifically is shaped and is used for certain device or application.And use in this article at term " top (top) " and " bottom (end) " only is description for the ease of rotary encoder 1.Therefore, rotary encoder 1 can use with any orientation.
In the specific example of Fig. 1 to Fig. 4, wheel for inputting 10 is included in the tooth 12 on the gear 11.Wheel for inputting 10 also comprises aperture 14, and it can be used from the device that the number of revolutions of following the trail of wheel for inputting 10 is provided with sensor one.Locking cap 16 is attached to wheel for inputting 10.As shown in Figure 3, when locking cap 16 was in the appropriate location, wheel for inputting 10 any moved the constraint that contacts be subjected to locking cap 16 and top mounting bracket 140.As long as rotary encoder 1 can comprise locking cap 16 will be handled upside down or load and transport the time, in case and input shaft prepare to engage rotary encoder 1 then locking cap 16 unloaded.
In the embodiment shown in fig. 1, code wheel 30 comprises gear 31 with tooth 32 and the pinion wheel 35 with tooth 36.Ring 37 and outer shroud 39 in code wheel 30 has, interior ring 37 has encoded segment 34, and outer shroud 39 has encoded segment 38.Encoded segment 34 and 38 top surfaces from code wheel 30 extend to the basal surface of wheel 30.Encoded segment 38 has continuous arcuate shape, and it occupies 1/2nd of outer shroud 39.Encoded segment 34 comprises two different arcuate segments, segmentation 34a and segmentation 34b, its respectively occupy in the ring 1/4th and each other equi-spaced apart open.Segmentation 34a starts from the radius identical with encoded segment 38.Segmentation 34b starts from the identical radius of encoded segment 38 terminations.Encoded segment can be asymmetric, as shown in Figure 1, or symmetry, such as the encoded segment of Fig. 5.The asymmetric orientation of encoded segment can be convenient on base plate 120 position that the non-encoded segment at the wheel that is not encoded partly stops and place redundant sensor.
In the present embodiment, code wheel 50,70,90 is identical with code wheel 30 with 110, and code wheel 60,80 is identical with code wheel 40 with 100.Yet any code wheel in these code wheels needn't be identical with any other code wheel.When using term " interior ring " or " encircling a plurality of in ", expression be each interior ring 37,47,57,67,87,97,107 and 117 in the code wheel 30 to 110.Only in fact the interior ring of timing wheel 20 and code wheel 30 and 40 numbers in Fig. 1.When using term " outer shroud " or " a plurality of outer shroud ", expression be each outer shroud 39,49,59,69,79,89,99,109 and 119 in the code wheel 30 to 110.Only in fact code wheel 30 and 40 outer shroud number in Fig. 1.When using term " encoded segment " or " a plurality of encoded segment ", expression be the encoded segment 24,34,38,44,48,54,58,64,68,74,78,84,88,94,98,104,108,114 and 118 of each code wheel in timing wheel 20 and the code wheel 30 to 110.Only in fact the encoded segment of timing wheel 20 and code wheel 30,40 numbers in Fig. 1.In addition, fixed timing mark 28 can be considered " encoded segment ".The data that produced by fixed timing mark 28 can be used for determining position and/or speed.Equally, can be used for determining position and/or speed by the data that other encoded segment produced.
The gear 11 of wheel for inputting 10 and 25 engagements of the pinion wheel of timing wheel 20.The gear 21 of timing wheel 20 and 31 engagements of the gear of code wheel 30.The pinion wheel 35 of code wheel 30 and 41 engagements of the gear of code wheel 40.The pinion wheel 45 of code wheel 40 and intermediate speed pinion 180 engagements.Intermediate speed pinion 180 meshes with the gear 51 of code wheel 50.The pinion wheel 55 of code wheel 50 and 61 engagements of the gear of code wheel 60.The pinion wheel 65 of code wheel 60 and intermediate speed pinion 180 engagements.Intermediate speed pinion 180 meshes with the gear 71 of code wheel 70.The pinion wheel 75 of code wheel 70 and 81 engagements of the gear of code wheel 80.The pinion wheel 85 of code wheel 80 and intermediate speed pinion 180 engagements.Intermediate speed pinion 180 meshes with the gear 91 of code wheel 90.The pinion wheel 95 of code wheel 90 and 101 engagements of the gear of code wheel 100.The pinion wheel 105 of code wheel 100 and intermediate speed pinion 180 engagements.Intermediate speed pinion 180 meshes with the gear 111 of code wheel 110.
As in Fig. 3 as seen, wheel for inputting 10 and code wheel 40,60,80 are in the plane identical with the pinion wheel of timing wheel 20 and code wheel 30,50,70,90 and 110 with 100 gear.Code wheel 40,60,80 is in the plane identical with the gear of timing wheel 20 and code wheel 30,50,70,90 and 110 with 100 pinion wheel.
Light splash guard (light splashguard) (not shown) can be outstanding from bottom erecting frame 130 and top erecting frame 140.Part in splash guard is arranged between ring and the outer shroud or completely in the concentric ring.For example, for code wheel 30, splash guard is arranged between interior ring 37 and the outer shroud 39.Splash guard can be designed to based on the basal surface (on the one hand) of timing wheel 20 and code wheel 30 to 110 and the distance between the bottom erecting frame 130 and have the height of variation.Splash guard provides the light barrier between the sensor 160.Splash guard can comprise and is built in the erecting frame 130 of bottom, is built in code wheel and the timing wheel 20 or is built in concentric ring in base plate 120 and the top board 170.Perhaps, block piece can individually form around sensor 160, or forms around detecting device 162 and transmitter 164.Splash guard can be the concentric ring that ridge, wall maybe can prevent any other structure of crosstalking between the different sensors 160.
Being engaged on of wheel for inputting 10, timing wheel 20 and code wheel 30 to 110 is shown as among Fig. 1 to Fig. 4 and is in the configuration of wriggling.Yet this configuration can be changed to satisfy different encoder design.For example, when needs were configured as circle with rotary encoder 1, wheel can be arranged to coiled arrangement.The various configurations of the different shape of rotary encoder 1 and wheel all are possible.Fig. 5 shows the alternative U-shaped configuration of the wheel in similar rotary encoder shape.
Wheel for inputting 10, timing wheel 20 and code wheel 30 to 110 are shown as spur gear.Yet wheel also can be worm gear, bevel gear, herringbone wheel, hypoid gear, ring gear, rack-and-pinion, and cross helical gear.Rotary encoder 1 shows the embodiment that code wheel has fixing rotation.Perhaps, can implement the rack-and-pinion system, wherein timing wheel 20 and code wheel 30 to 110 do not have fixing rotation.
To specific embodiment shown in Figure 4, the interior ring and the outer shroud of different coding wheel are positioned apart from the same distance place, center of wheel referring to Fig. 1.For example, interior ring 37 is identical apart from the distance at wheel 40 centers with interior ring 47 and encoded segment 44 apart from the distance at wheel 30 centers with encoded segment 34, even have under the situation of larger diameter at wheel 40.Therefore, the number of tooth 42 and tooth 36 40 speed with respect to wheel 30 that can determine to take turns reduce.This is equally applicable to other and takes turns.Yet the encoded segment of different coding wheel needn't equidistantly be located diametrically.
The speed of wheel for inputting 10 is determined by the speed of whirligig to be monitored.For example, in the present embodiment, timing wheel 20 rotates than about 1.34 times soon of wheel for inputting 10.Code wheel 30 rotates with the speed identical with timing wheel 20.Code wheel 40 is with 1/4th rotations of the speed of code wheel 30.Code wheel 50 is with 1/4th rotations of the speed of code wheel 40, and code wheel 40 rotates with ten sixth speed of the speed of code wheel 30.This is equally applicable to other code wheel, makes code wheel 110 rotate with 1/4th of the speed of code wheel 100, and code wheel 100 rotates with 1/65,536 of the speed of code wheel 30.In some cases, code wheel 30 will rotate, but be not enough to cause the rotation of code wheel 110.In alternate embodiment, extra code wheel can add rotary encoder 1 to.The speed of extra code wheel can be calculated as 1/4 of code wheel 30
n(carry out following counting, code wheel 30 is n=0, and code wheel 40 is n=1 ..., code wheel 110 is n=8, or the like).Specific embodiment of the present invention can comprise a following code wheel: it has the wheel that less bit number is used for top speed, but allows to increase the higher bit number that each is taken turns along with the reduction of relative coding wheel speed when the train transmission.
May exist needs to change the situation of the number of teeth between wheel and the wheel.For example, do not have under the situation of the identical number of teeth with 60 at code wheel 40.In addition, in conjunction with the number of teeth that changes on the gear, the radial position of encoded segment can be taken turns change with respect to another, to cause speed to reduce or to increase.
Wheel can be made by any kind of material.The representative illustration of minority is steel, stainless steel, aluminium, other metal, pottery, plastics, glass and the plastics that are covered with metal.Can use any material that is used for gear known in the art.These are taken turns and can all be made by identical composition, and perhaps the composition between wheel and the wheel can be different.
As referring to shown in the code wheel 80, sensor 160 comprises detecting device 162 and transmitter 164.Detecting device 162 and transmitter 164 are built in the base plate 120.Gap 34 is built in the erecting frame 130 of bottom, to prevent to cover detecting device 162 and transmitter 164.About transmitter 164 and detecting device 162, can be via semiconductor fabrication, transmitter 164 and detecting device 162 be installed on the base plate 120 and transmitter 164 and detecting device 162 are inserted through hole in the base plate 120, thereby transmitter 164 and detecting device 162 are manufactured in the base plate 120.Will be appreciated that any other method that transmitter 164 and detecting device 162 are fastened on the base plate 120 also is covered by in the present invention.Gap 144 (Fig. 4) is built in the top erecting frame 140 and has and gap 134 identical functions.Although not shown, rotary encoder 1 also can comprise sensor, and it comprises transmitter and detecting device, and transmitter and detecting device are built in the basal surface of top board 170.For each detecting device 162 that is built in the base plate 120, transmitter can directly be arranged in the top.For each transmitter 164 that is built in the base plate 120, detecting device can directly be positioned over the top.Gap 144 in the top erecting frame 140 shown in Figure 4 prevents that 140 pairs of transmitters of top erecting frame and any of detecting device from stopping.Be positioned on the basal surface of top board 170 sensor, detecting device and transmitter usually be located immediately at above sensor 160, transmitter 164 identical with detecting device 162.Therefore, for the ease of the discussion of this paper, be positioned at member on the base plate 120 substantially similar be positioned at any respective members on the top board 170, although do not illustrate in the drawings, but will give the identical Reference numeral that adds quotation marks (') mark (for example, detecting device 160 and detecting device 160 ').
Shown embodiment comprises sensor 160,161,163 and 165.Sensor 161 is corresponding to the interior ring of timing wheel 20 and code wheel 30 to 110.Sensor 163 and 165 outer shrouds corresponding to code wheel 30 to 110.Sensor 160 ', 161 ', 163 ' and 165 ' respectively directly be positioned over sensor 160,161,163 and 165 tops.Sensor 163 and 165 can be placed to the radial angle of about 90 degree spaced apart.In code wheel 30,60,70,100 and 110, sensor 161 can be divided the angle between sensor 163 and 165 equally.In code wheel 40,50,80 and 90, sensor 161 and 163 can be spaced apart with the radial angle of about 45 degree, and sensor 161 and 165 can be spaced apart with the radial angle of about 135 degree.Sensor 161,163,165 and 169 is only about code wheel 80 and 100 and timing wheel 20 numbering.Each sensor 161,163 and 165 comprises transmitter 164 and detecting device 162.Each sensor 161 ', 163 ' and 165 ' comprise transmitter 164 ' and detecting device 162 '.
Sensor 160/160 ' comprise transmitter 164/164 ' and detecting device 162/162 ', and can be described to one group of sensor to or two groups of sensors.This be equally applicable to sensor 160/160 ' and 160 '/160 " concrete form (that is, sensor 161,161 ', 163,163 ', 165,165 ', 169 and 169 ').As transmitter 164 and detecting device 162 are considered as a pair of and with transmitter 164 ' with the substituting of relative the second couple of detecting device 162 ' be considered as, transmitter 164 and detecting device 162 ' can be considered are a pair of, transmitter 164 ' and detecting device 162 can be considered parallel the second couple.In any case but think that second pair can provide duplicate detection.This redundancy makes that rotary encoder 1 can be fault-tolerant to heavens.For example, if one such to breaking down, rotary encoder 1 still can be operated so.According to which sensor or sensor component may break down (if existence), scrambler also can utilize a plurality of sensors of actuating and operate.
In a specific embodiment, the position of the transmitter 164 of sensor 160 and detecting device 162 be give sensor 160 (with respective sensor 160 ') position of placement tolerance that may be wide and the most symmetrical.Before bit value changed once more, for sensor, the position that code value changes was left identical space in clockwise (CW) direction with counterclockwise (CCW) direction.This method is shown in Figure 1.In a specific embodiment, this causes the corresponding asymmetry of asymmetric sensor placement and code change point.
In an alternate embodiment, transmitter 164 can be with respect to detecting device 162 skews.Then can more resulting first encoded radio and the skew encoded radio, identical to guarantee two arithmetical differences between the value.If arithmetical difference is inequality, then can search this problem by following self-test.
In arbitrary embodiment, as long as this v of being placed on bit prevents in the boundary of gap logic (anti-backlash logic) and in the boundary of the permissible mechanical tolerance of member, the code that is produced will be identical so.
In an alternate embodiment, sensor 161,163 and 165 can respectively have single transmitter, corresponding sensor 161 ', 163 ' and 165 ' can respectively have corresponding single detector and not have any redundancy.
Each sensor is associated with fixed timing mark 28.Sensor 169 shown in Figure 1 comprises at least one transmitter 164 and at least one detecting device 162.Be positioned at sensor 169 on the top board 170 ' directly be positioned over sensor 169 tops, and comprise at least one transmitter 164 ' and at least one detecting device 162 '.
In a specific embodiment, the respective sensor that is positioned on base plate 120 and the top board 170 can once be actuated a wheel respectively.Perhaps, can once actuate these whole in taking turns or some.Each bottom of taking turns at first is actuated usually, is each top side of taking turns afterwards.In a specific embodiment, but actuation sensor 160/160 ' each transmitter.Actuate continuously each sensor 169/169 of being used to monitor fixed timing mark 28 ', as discussing in more detail hereinafter.About code wheel 30 to 110, but the transmitter 164 of actuation sensor 161,163 and 165.If rotary encoder 1 is in position shown in Figure 1, so sensor 161 ', 163 ' and 165 ' detecting device 162 ' each receives the signal from respective transmitter 164.Yet, rotary encoder 1 only can be located such that sensor 161 ' and 163 ', 161 ' and 165 ', 163 ' and 165 ', 161 ', 163 ' and 165 ' detecting device 162 ' received signal or the received signal not of the detecting device 162 of all these sensors ' all.No matter where rotary encoder 1 is positioned at, detecting device 162 will be when transmitter 164 be actuated received signal.In a specific embodiment, transmitter 164 and detecting device 162 can be vertically with about direct communication.Therefore, when actuating three transmitters 164, three detecting devices 162 are received signal, and if the opening in the encoder wheel (that is, encoded segment) transmitter 164 and detecting device 162 ' between, but three detecting device 162 ' received signals so.Therefore, produce the data of 6 bits.
Adopt this mode, when actuate the sensor 161 that is positioned on the top board 170 ', 163 ' and 165 ' 164 ' time of transmitter, produce the data of 6 bits.Actuate the detecting device 162 of identical sensor ', and the detecting device 162 of the sensor on the bottom side of rotary encoder 1 161,163 and 165.Can actuate the sensor 161,163 and 165 of code wheel 30.Then, can actuate the sensor 161 of code wheel 30 ', 163 ' and 165 '.About code wheel 40 to 110, can continue this alternative sensor and actuate pattern.
About timing wheel 20, sensor 161 and 161 ' can be as mentioned is described and actuate about code wheel 30 to 110.In a specific embodiment, continue actuation sensor 169 and 169 ' transmitter.In the embodiment shown in Figure 2, sensor 169 ' comprise two transmitters, sensor 169 comprises two detecting devices.In a specific embodiment, all other sensor respectively has transmitter and detecting device.In a specific embodiment, actuation sensor 169 transmitter only once.
The first detecting device 162a and the second detecting device 162b can be located such that fixed timing mark 28 is not present on the second detecting device 162b when fixed timing mark 28 is present on the first detecting device 162a.This is shown among Fig. 1, and wherein detecting device 162a and optional transmitter 164 are visible, but detecting device 162b is sightless.
Perhaps, sensor 169 and 169 ' can respectively have transmitter and detecting device, and can forbid (disable) directly left and right sides transmission characteristic.Can by use sensors of various types or detecting device 162 and 162 ' and/or transmitter 164 and 164 ' edge placed around block piece forbid this specific character.
Sensor 169 and 169 ' also can comprise other transmitter and detecting device.For example, Fig. 2 illustrates the detecting device 164 in the sensor 169, its corresponding to sensor 169 ' in detecting device 162 '.Transmitter 164 can be positioned over apart from first detecting device 162a distance enough far away, makes the detecting device 162a receiving optical signals not when actuating transmitter 164 of winning.In an alternate embodiment, transmitter 164, the first transmitter 164a ' and the second transmitter 164b ' alternately actuate.
Three grades of redundancies of sensor 160 and 160 ' provide.At first, if transmitter 164 ' and 164 and detecting device 162 ' with 162 in any inefficacy, sensor 160 and 160 ' remain exercisable so.For example, if the transmitter of the sensor 161 of code wheel 80 164 lost efficacy, sensor 161 still can be operated so because sensor 161 ' transmitter 164 ' still can communicate by letter with the detecting device 162 of sensor 161.
Second level redundancy is from the built-in self-test function.Detecting device 162 is placed near the transmitter 164 and self-test is provided.Even because the position of code wheel and do not have accessible light path, detecting device 162 will be when actuating transmitter 164 received signal.If detecting device 162 is received signal not, any in transmitter 164 and the detecting device 162 (or subsidiary circuit and processing) or two are broken down so.In case code wheel moves to the position that has accessible light path,, then may be that transmitter 164 breaks down if detecting device 192 does not receive signal.Detecting device 162 ' and life-span of 164 can be by actuating transmitter 164 ' determine.If detecting device 164, detecting device 162 ' or transmitter 164 ' begin to break down rather than transmitter 164 breaks down adopts similar logic so.
When definite which position during by sensor 160 and 160 ' identification, processor 150 will be considered the member of any inefficacy, such as transmitter 164 or detecting device 162 '.For example, if the detecting device 162 of the sensor 163 adjacent with code wheel 80 lost efficacy, processor 150 can compensate at the following fact so, i.e. sensor 163 and 163 ' will not detect the light path that stops of identical point in code wheel 80 rotations.Whether perhaps, use identical example, if detecting device 162 received signal not, detecting device 162 can be tested by adjacent transmitter 164 so, be operation to determine detecting device 162.Transmitter 164 ' can be by adjacent detector 162 ' test is to determine transmitter 164 ' whether be the reason of problem.If transmitter 164 ' and detecting device 162 for operation and transmitter 164 ' sending, but detecting device 162 does not receive this transmission, so outer shroud 89 stop transmitter 164 ' and detecting device 162 between light path.And, if detecting device 162 had lost efficacy, but the position of processor 150 estimated codings wheel 30 to 70 and 90 to 110 so, to determine in fact whether outer shroud 89 stop the detecting device 162 that breaks down.
Can by utilize Viterbi (Viterbi) decoding by sensor 160 and 160 ' in any triple redundance is provided.For example, the output of the output of sensor 163 or sensor 165 can be used for producing Viterbi bit (v-bit).If sensor 160 or sensor 160 ' inoperation are to produce the v-bit, sensor 160 or 160 ' be used to produce data-bit so.In a specific embodiment, sensor 165 and 165 ' be used to produce v-bit.The Veterbi decoding algorithm is a forward error correction technique.The V bit provides and can be used for the redundant data accurately decoded in other the position of 2-bit.In this embodiment, the sensor 161 and 161 ' 1-Bit data can be provided, the sensor 163 and 163 ' 2-Bit data can be provided.By using the v-bit, by sensor 161 and 161 ' and sensor 163 and 163 ' signal that is produced can be with the angular deflection of optimum position+/-22.5 spend and do not cause code error.Therefore, even there is received signal under the situation about being offset, also incite somebody to action the still actual position of indicator wheel.The actual position of the also clear and definite adjacent encoder wheel of the v-bit on a code wheel.For example, the v-bit of code wheel 30 helps the actual position of clear and definite code wheel 40.
Veterbi decoding is not that code wheel 30 to 110 can be designed to unique solution code calculation that it is implemented.Be used for other appropriate algorithm of the present invention and for example comprise sequential decoding, reed solomon coding (Reed-Solomon coding) and turbine coding (turbo coding).It is the gear counting that another of Veterbi decoding substitutes.
In rotary encoder 1, the sensor 165 that produces the v-bit is with respect to sensor 161 and 163 skews.Perhaps, sensor 165 can be arranged to align with the sensor 163 or 161 that produces data-bit.Fig. 5 shows the embodiment of absolute encoder (rotary encoder 2), and wherein v-bit sensor 2165 is positioned to align with data-bit sensor 2161 and be offset with respect to data-bit sensor 2163.As reference timing wheel 2020 as seen, the encoded segment 2034 in v-bit sensor 2165 also can be positioned to detect on the ring 2027.V-bit sensor 2165 can be oriented to detect any code wheel or the whole interior rings of code wheels in the code wheel 2030 to 2110.Therefore, sensor 161 or sensor 2161 can be the v-bit.
Except difference seldom, rotary encoder 2 shown in Figure 5 is similar to rotary encoder 1 and operates.Wheel for inputting 2010 has the different numbers of teeth.Encoded segment 2024 is divided into two parts rather than four parts with interior ring 2027.In addition, sensor 2165 is included in the concentric ring identical with sensor 2161.Timing wheel 2020 comprises pinion wheel 2025, and intermediate speed pinion 2180 is on the either side of pinion wheel 2025.
Wheel for inputting 2010 and intermediate speed pinion 2180 engagements, and pinion wheel 2025 engagements of intermediate speed pinion 2180 and timing wheel 2020.Pinion wheel 2025 and intermediate speed pinion 2180 engagements, and gear 2031 engagements of intermediate speed pinion 2180 and code wheel 2030.The pinion wheel 2035 of code wheel 30 and 2041 engagements of the gear of code wheel 2040 are by that analogy until code wheel 2110.Code wheel 2030 to 2110 meshes in the mode identical with code wheel 30 to 110.
In the present embodiment, the tooth of wheel for inputting 2010 and code wheel 2030,2050,2070,2090 and 2110 gear can be configured to be arranged in the identical plane of pinion wheel with timing wheel 2020 and code wheel 2040,2060,2080 and 2100. Code wheel 2030,2050,2070,2090 can be arranged in the plane identical with the gear of code wheel 2040,2060,2080 and 2100 with 2110 pinion wheel.
Referring to rotary encoder 1, sensor 160 and 160 ' provide rotates the indication of absolute position of the input shaft of wheel for inputting 10.As shown in the figure, rotary encoder 1 is 18 bit absolute encoders.Therefore, rotary encoder 1 can be represented 262,144 positions.Certainly, need not to use all positions.Can increase or dwindle rotary encoder 1 by adding wheel and sensor to the end of train or reducing wheel and sensor from the end of train.Each take turns can provide three sensors 160 and 160 '.Perhaps, each in the train take turns or at least last take turns only can provide one or two sensor groups 160 and 160 ', as long as sensor is oriented to as the more high-order bit of the next one in the encoded radio.Rotary encoder 1 also can only have single encoded the wheel, and it is as the source of speed and position data.Rotary encoder 1 also can only have single position encoded the wheel and independent velocity pick-up mechanism, such as timing wheel.In addition, each in the code wheel can have any a plurality of encoded segment and corresponding sensor 160 and 160 '.Rotary encoder 1 can be utilize sensor 160 and 160 ' any encoder design.
As discussed above, sensor 160 and 160 ' can when encoded segment is arranged between the sensor, communicate by letter, thus accessible light path is provided.In sensor 160, when receiving signal, detecting device 162 output logics 0 value; Output logic 1 value when not receiving signal.Equally, sensor 160 ' in, detecting device 162 ' output logic 0 value when receiving signal; When not receiving signal, output logic 1 value.Therefore, when encoded segment sensor 160 and sensor 160 ' between the time, when actuating transmitter 164, processor 150 receives two independent logics inputs: input from the detecting device 162 of detection position ', an input is from the detecting device 162 of carrying out self-test.In case stop using transmitter 164 and actuate transmitter 164 ', processor 150 receives 2 independent logics inputs so: 162, one logics inputs of detecting device that logic input is come the detection position from the detecting device 162 of carrying out self-test '.
If interior ring or outer shroud block sensor 160 and 160 ' between communicate by letter, processor 150 logical one that will receive the logical zero input of the bit value of representing position code and the successful test of representing the transmitter that the bit position is relevant is therewith imported so.For example, when actuating transmitter 164, detecting device 162 ' will be blocked and can not received signal and will send logical one.Detecting device 162 still transmits and received signal about directly, and therefore logical zero is sent to processor 150.
When processor 150 from detecting device 162 ' receive logic 0 signal and when relatively transmitter 164 is actuated, processor 150 is recognized and is had encoded segment certainly.When actuating transmitter 164 ' and detecting device 162 when transmitting logic zero signals, realize identical result.Present embodiment use 0 and logic zero signal; Yet, also can use 0 and 5 volt, 1 and 5 volt or any other sensor signal commonly used or its combination.Produce 0 volt when in addition, detecting device 162 and 162 ' can be designed so that produces logical zero and receives light signal when not receiving light signal.In such embodiments, processor 150 will receiving sensor 160 and 160 when 0 volt of detecting device 162 ' receive and transmitter 164 are actuated ' between the indication of encoded segment.
In a specific embodiment, the self-test of being undertaken by 164 pairs of adjacent detector of transmitter 162 is carried out to the direct transmission of detecting device 162 by the sidepiece from transmitter 164.For example, can be positioned at apart from the distance of transmitter 164 be the 0.5mm place to detecting device 162.Perhaps, can use the sensor that transmits about can not be directly.In such embodiments, can carry out self-test via reflection.For example, when sensor 160 and 160 ' between when having encoded segment and actuating transmitter 164, detecting device 162 ' received signal only.When actuating 164 ' time of transmitter, detecting device 162 received signals only.This will allow transmitter 164 and 164 ' actuate simultaneously.When do not exist encoded segment make light sensor 160 and sensor 160 ' between when being blocked, detecting device 162 and 162 ' can be suitable for receiving reflected light signal.In this case, when actuating transmitter 164, light can emit from the basal surface of interior ring or outer shroud.Detecting device 162 can receive a catoptrical part.Detecting device 162 can be designed to transmit logical zero receiving under the situation of any light.Detecting device 162 can be designed to transmit and the suitable voltage of light intensity that is received.Therefore, when having encoded segment, detecting device 162 can be from being positioned at the directly direct optical signal of the transmitter 164 ' reception higher-strength of top of detecting device 162.When not having encoded segment, detecting device 162 can receive more low intensive reflected light signal from adjacent transmitter 164.
In another embodiment, encoded segment can be coated with and be drawn on the wheel, rather than depends on the incision segmentation of wheel.In such embodiments, sensor 160 and 160 ' between do not communicate by letter.On the contrary, detecting device 162 receives reflected light from transmitter 164.This be equally applicable to detecting device 162 ' and transmitter 164 '.For example, if the wheel right and wrong are reflexive (for example, painted black) and encoded segment be reflexive (for example, painted white) or wheel be reflexive and the encoded segment right and wrong reflexive, detecting device 162 ' will produce a voltage when encoded segment reflects and when non-encoded segment reflects, produce different voltage so at light at light.In addition, sensor 160 and 160 ' can be positioned at the at first same side of code wheel.
Sensor 160 and 160 ' be described about optical sensor.Yet, will be appreciated that a plurality of other sensors can be used for the present invention.The suitable example of other of sensor includes but not limited to magnetic sensor, hall effect sensor and electric contact.The sensing that becomes known for any kind of increment sensor and absolute encoder in this area can be used for the present invention.Encoded segment also can comprise any material or the configuration with selected sensor compatibility.
Processor 150 also can be designed to produce alarm.If detecting device 162, transmitter 164, detecting device 162 ', transmitter 164 ', detecting device 162a, detecting device 162b, transmitter 164a ' or transmitter 164b ' inefficacy, processor 150 can give the alarm.Can provide different alarms for different inefficacy priority.Under extreme case, processor 150 can be designed to force valve actuator or other whirligig monitored by rotary encoder 1 to shut down.Can express alarm in many ways, such as, visual alarm (such as flash of light or LCD message on the control panel of valve actuator or on control station), audible alarm or written warning.
Sensor 160 and 160 ' in, if transmitter 164 and 164 ' and detecting device 162 and 162 ' can not proper function, so data-bit that is produced or v-bit will be declared as invalid.Can and judge that invalid bit value is for the valve actuator of being monitored by rotary encoder 1 or the Effect on Performance of other whirligig actuation time based on the decode value of inefficacy bit.Also can estimate invalid bit value based on the bit number that lost efficacy.
Be valve used time from the open position to the off-position or from the off-position to the open position actuation time of valve actuator.Be that whirligig rotates to the used time of the second place from primary importance the actuation time of other whirligig.For example, for industrial reel, be that this reel launches the used time fully from being wound up into fully actuation time.When actuation time was longer, individual bit was only corresponding to the sub-fraction of total actuation time.Therefore, it may not be very crucial that individual bit lost efficacy, thereby alarm or warning are provided but do not force machine down, and this can be enough to be used in such application.If actuation time is shorter, individual bit lost efficacy can represent between the represented position of physical location and rotary encoder 1 than large deviation.Therefore, for short actuation time, except alarm or warning were provided, individual bit lost efficacy can be enough to force whirligig to be shut down.The importance of bit fails can be depending on should actuation time for given application which part can represent by bit fails.In a specific embodiment, the user can dispose the threshold value of the loss of accuracy of being allowed, if be lower than this threshold value, the BIST feature only provides alarm or warning, but is higher than this threshold value, and the BIST feature will force secure machine to shut down and provide alarm or warning.
For the whirligig that does not have the predetermined primary importance and the second place, can be unfixed actuation time.The example of such whirligig comprises the flywheel of engine or the main shaft of turbine.Rotary encoder of the present invention also can be used for the whirligig of any kind.
As mentioned above, if sensor 160 and 160 ' detecting device 162 and 162 ' all be verified as exercisable by self-test, but detecting device 162 does not receive signal and detecting device 162 ' received signal, can check that so other position of taking turns is to confirm the position of associated wheel.In this case, be actually effectively by the data-bit of sensor 160 and 160 ' produced, but sensor 160 and 160 ' half stopped by interior ring or outer shroud.Viterbi logical operation can obtain identical position code from main sensors group or redundant sensor group (that is, transmitter 164 or detecting device 162).Will be appreciated that term " mainly " and " less important " or " redundancy " are arbitrarily.
Perhaps, sensor 160 and 160 ' can work fully, but the different component of rotary encoder 1 lost efficacy.For example, if in the tooth on the code wheel is cut, so by the current location of sensor 160 and 160 ' indicated can with based on the past data of sensor 160 and 160 ' provided and the position of predicting do not match.Therefore, though sensor 160 and 160 ' operate as normal, they are the indicating correct position not.Processor 150 or some other processor can provide for the correction of this mistake and produce alarm.For example, if code wheel 60 loses tooth 62 from gear 61, code wheel 60 may begin to miss the position during each rotation so.Therefore, will be by the valve position of all code wheel indications no longer accurately corresponding to valve position.This will show as valve bounce to the another location.In one embodiment, processor 150 can be searched the discontinuous of the indicated valve position in the position of code wheel.As an alternative or as a supplement, timing wheel 20 can be used as the position of incremental encoder with the checking code wheel.Processor 150 (or any other suitable processor) can recomputate valve position under the situation of considering the mistake that code wheel 60 is introduced.If the order of severity that lost efficacy is bigger, processor 150 also can produce alarm and/or cause safe shutdown so.
Any other processor that causes any inefficacy of rotary encoder 1 of the discontinuous indication of valve position to communicate by letter by processor 150 or with processor 150 is discerned.
Sensor 160 and 160 ' be described to have transmitter and detecting device respectively in this article.Perhaps, sensor 160 can be configured to only have transmitter and sensor 160 ' can be configured to only have detecting device.In other embodiments, sensor 160 ' can not be present in the rotary encoder 1.Fig. 2 illustrates sensor 160 and has a plurality of transmitters and detecting device.Sensor 169 comprises transmitter 164, the first detecting device 162a and the second detecting device 162b.Although not shown, sensor 169 ' comprise relevant detection device 162 ', the first transmitter 164a ' and the second transmitter 164b '.The second detecting device 162b and the second transmitter 164b ' can be used for verifying from the data of the first detecting device 162a and the first transmitter 164a ' or the data output by sensor 169 and 169 ' produced are doubled.Sensor 160 can comprise arbitrarily a plurality of transmitters, detecting device and/or the two.Sensor 160 and 160 ' can be used for any rotary encoder so that fault-tolerant speed and position data to be provided.
Fig. 1 to Fig. 5 shows absolute encoder, ring and outer shroud in wherein each in the code wheel only has.Yet, the ring of each the had arbitrary number in the code wheel, and without limits.For example, each code wheel can have 3,4,5 or 6 rings.For each ring can provide at least one sensor 160 and at least one sensor 160 '.Therefore, the number of ring can determine the number of the producible data-bit of each code wheel.
The number of the ring of each code wheel is by allowing the sensor 160 and 160 ' size of the required code wheel that communicates with one another and the width of encoded segment to decide.In addition, provide enough gaps to be limited in crosstalking between the sensor on the same side between the Ying Zaihuan.For example, the signal that provides the gap to write down from the transmitter 164 of sensor 163 with the detecting device 162 that prevents sensor 161.Yet, also can use other technology except the gap, such as using the splash guard above discussed, crosstalk and allow littler code wheel diameter with restriction.
The code wheel of arbitrary number can add scrambler of the present invention to.For example, can be provided actuation time is the position data of one hour common speed valve actuator to rotary encoder 1.Adding a plurality of code wheels will provide the more data bit and increase the actuation time that can be handled by rotary encoder 1.Certainly, rotary encoder 1 also can be used for actuation time less than one hour valve actuator and other whirligig.Rotary encoder 1 also can have than Fig. 1 to code wheel code wheel still less shown in Figure 4.
In addition, rotary encoder 1 can be single wheel absolute encoder or single-wheel incremental encoder.In these embodiments, sensor 160 and 160 ' can comprise a plurality of transmitters and detecting device, thus built-in self-test and fault tolerant operation are provided.Therefore, one group of sensor 160 and 160 ' can monitor a plurality of encoded segment, such as fixed timing mark 28 or encoded segment 34, perhaps one group of sensor 160 and 160 ' can monitor single encoded segmentation, such as encoded segment 38.
In addition, timing wheel 20 can be used as the incremental encoder that combines with the specific coding function of the remainder of rotary encoder 1.For example, particular delta scrambler embodiment can be set at pro rata and can make delta pulse speed mate the count rate of the absolute part of scrambler exactly.In this way, incremental encoder can be used for obtaining position data when actuator is operated.When motor stopped, accurately mating the specific coding position of adding the final increment counting Ying Yuxin of absolute position code when motor revolution beginning to.
If the indicated position of timing wheel 20 (also playing the effect of incremental encoder) is different from by the indicated position of code wheel, so can be to sensor 160 and 160 ' execution self-test.If all the sensors 160 and 160 ' equal proper function is confirmed in self-test, may follow the trail of by code wheel so undesiredly.Therefore, can produce alarm or warning.In a specific embodiment, in this case, rotary encoder can be dependent on incremental encoder up to the maintenance rotary encoder.
The many kinds of whirligigs that the present invention can be used for rotating between the two positions, such as, valve actuator, door opener or reel.In typical valve actuator, motor can come driver's valve via one group of gear.The output shaft of motor can directly be connected to worm screw.Worm screw can drive Worm-gear assembly, and Worm-gear assembly drives drive socket or axle again, and drive socket or axle lifting and reduction or rotation valve rod.Second also can be driven by Worm-gear assembly, so that the wheel for inputting 10 of driven in rotation scrambler 1.Perhaps, valve actuator can use different gear sets, and perhaps motor output shaft can directly be connected to valve rod and need not the center tooth wheels.Exist a variety of being applicable to of the present invention the position of rotation scrambler to be connected to the method for whirligig in the art, but these methods will set off a discussion no longer herein.In a preferred embodiment, rotary encoder 1 and 2 can be used for the whirligig such as valve actuator is carried out diagnosis, and about diagnostic function, rotary encoder 1 will be as demonstrative example.Yet, also can use other scrambler of the present invention, such as rotary encoder 2.In addition, timing wheel 20 can merge in any rotary encoder.Timing wheel 20 can be the code wheel of incremental encoder or the code wheel of single wheel absolute encoder.For example, fixed timing mark 28 can be used for the position encoded of absolute encoder.Perhaps, as shown in Figure 1, timing wheel 20 also can comprise the encoded segment of separating with fixed timing mark 28.In another embodiment, fixed timing mark 28 can be the part than the unitary Item pattern, such as the coding pattern of single wheel absolute encoder.In a specific embodiment, timing wheel 20 can be the incremental encoder that separates or combine with other code wheel.In this embodiment, fixed timing mark 28 not only is used to produce speed data, and produces the incremental counter data.Fixed timing mark 28 is similar to encoded segment, can take with sensor 160 and 160 ' work required any form or structure.Fixed timing mark 28 can be any other structure that becomes known for absolute encoder or incremental encoder in hole, line, embedding magnet, engraving or this area.
Timing wheel 20 and 2020 is shown as has 32 fixed timing marks 28 and fixed timing mark 2028.Yet timing wheel 20 and 2020 can have the fixed timing mark 28 of arbitrary number.
About frequency analysis, the initial hereinafter specific embodiment of speed data being carried out frequency analysis (also being known as frequency-domain analysis in this article) of discussing is discussed non-speed data embodiment afterwards.In addition, for purpose of explanation, the fixed timing mark 28 of timing wheel 20 or timing wheel 20 usually is known as the speed data source in this article.In other embodiments, no matter the speed pickup of any kind has rotational position sensor and does not still have rotational position sensor, can be used for diagnosis (that is frequency analysis).In addition, the discussion about the frequency analysis of speed data is equally applicable to other data embodiment.Other data embodiment can for example comprise the volt-ampere response data and the vibration data of moment of torsion data, position data, thrust data, noise data, current data, voltage data, power of motor data, motor.Numerous types of data and sensor type can be used for frequency analysis, as known in the art.The present invention is contained can be via sensor and valve actuator or the producible any data type of other whirligig.
Although discussion hereinafter relates to rotary encoder 1, will be appreciated that this discussion is equally applicable to rotary encoder 2.Fixed timing mark 28 on the timing wheel 20 can be used for producing speed data.But each in sensor 169 and the 169 ' recording timing mark 28 is presented in the time span before the sensor.This residence time can be used for accurately determining the speed such as the whirligig of valve actuator then.Speed data can be used for definite speed that drives the input shaft of wheel for inputting 10.And input shaft usually is attached to other whirligig, such as the worm gear of valve actuator.Therefore, fixed timing mark 28 can be used for determining the speed such as other whirligig of worm gear.
In a particular embodiment, fixed timing mark 28 is configured at timing wheel 20 intermediate reach and waits big or small hole.Yet, any embodiment among previous encoded segment embodiment that discusses and the sensor embodiment also be respectively applied for fixed timing mark 28 and sensor 169 and 169 ' embodiment.
Can utilize FT to operate by the speed data that fixed timing mark 28 is produced, to convert speed data to frequency domain from time domain.Yet, can use the speed pickup of any kind to produce speed data, to convert frequency data to.
FT expection signal sample took place with the regularly spaced time interval.Yet, because the residence time value of rate signal in the present invention may not be constant, so can adopt measure to obtain effective information to allow FT.By selecting enough lot of data points, when machine is operated with stable state, the overwhelming majority in these data points will be used, and the average residence time of larger data collection can be used as " rule " residence time [t of each data sampler
d].This ' rule ' residence time can be used for demarcating the frequency scaling (fn (Hz)=l/ (td*# sample) of (scale) gained FT.When spot frequency data suitably, data provide enough information to determine the velocity variations that is associated with the known rotational speed of each member of power train to the operator, but and problem existing or that occur possibly in the power train of indicator valve actuator or other whirligig.For example, when equipment is new, will forms the chart or the curve of bareline heart rate and amplitude and preserve.Afterwards, can form the chart of new frequency and amplitude or curve and compare with baseline chart or the curve preserved.If the peak value corresponding to the operating frequency of given member appears at and previous measured frequency or different frequency or the amplitude places of amplitude, it is evident that so, be different from newer the time these indication wearing and tearing and may losing efficacy or imminent inefficacy usually with the characteristic of the member of this frequency dependence connection.Therefore, can before component failure, carry out suitable maintenance in the suitable time.In addition, can plan to carry out FT and analyze, with operation automatically in processor 150, the peak amplitude variation that processor 150 can be programmed and be configured so that to surpass the threshold value that is disposed can be used for producing automatic alarm or warning or forces the machine safe shutdown.Can use the method for any suitably spot frequency data as known in the art.
The example of frequency-domain analysis is included among Fig. 6 to Fig. 8.Fig. 6 illustrates the example of valve actuator no problem diagnosis or " well " power train in frequency domain.Fig. 6 shows the peak value at 45.9Hz; Yet the peak value of 0.1% amplitude of measuring with respect to the operating speed of actuator (when 26rpm or 0.43Hz, amplitude is 100%) does not have the amplitude that is enough to cause concern.Fig. 7 is illustrated in the valve actuator of the some undesired signals of generation in the frequency domain or the example of " bad " power train.The frequency of undesired signal can be used for discerning the power train member that goes wrong.In Fig. 7, worm screw or worm gear exceed tolerance limit.For example, the peak value indication at 26.1Hz goes wrong.Yet, be the harmonic wave of 26.1Hz peak value at the peak value of 52.5Hz and 78.6Hz.
The processor of processor 150 or execution FT can be designed to automatically produce the suitable mark that is used for remarkable peak value (for example, above predetermined threshold).For example, processor can comprise amplitude that is designed so that current peak value that produces and the previous peak value that produces and the program that frequency is complementary.In this embodiment, if processor can not be discerned peak value, this inefficacy can be used as the warning that has potential problems to the operator so.Perhaps, the data in the frequency domain can be manually relevant with the parts of the power train of valve actuator.But the training and operation person discerns and understands the correlativity of different peak values.For example, if rotary encoder 1 is present in the valve actuator, timing wheel 20 and sensor 169 and 169 ' can be used for the discerning speed of power train member so.In a specific embodiment, drive the input shaft of wheel for inputting 10 by worm-gear driven.Therefore, speed pickup can be used for determining the speed of worm gear, and therefore determines frequency.Then, based on the gear ratio, can calculate the frequency of other power train member.Then, can come identification means frequency and any harmonic wave according to the graphical representation of the data in the frequency domain.On the other hand, if speed pickup is not present in the valve actuator, but the motor shaft speed of known reality, this information can be used for producing the member frequency so.Can adopt the various types of electrical measurements or the magnetic measurement of the actual speed of motor, therefore further improve the diagnosis capability of system in its entirety.In many cases, factory personnel will be carried out above-mentioned manual identification.Therefore, can provide the sample frequency curve and the mutual relationship of mark in advance to the terminal user.
In a specific embodiment, can download the built-in information (gear ratio, motor speed, the tooth of each gear, the ball of each bearing etc.) of actuator, in the Electronic Packaging that is stored in actuator.Then, airborne CPU can cause this variation with reference to stored information and which part of deriving power train.The drawing of FT can directly be shown on the LED screen of actuator, and perhaps the data array resource management system that can be downloaded to the operator is used to analyze or be downloaded to the portable computer of service technician or PDA and goes up and make a concrete analysis of to be sent to main office.
The programming that is used for collecting data and/or carry out frequency analysis can be stored in firmware, software, hardware or any other device as known in the art.For example, the frequency analysis programming can be stored in the firmware of valve actuator.
In addition, the operator can be simply by comparing present analysis and the previous peak value of discerning in the frequency domain of analyzing.The previous analysis can be the analysis of carrying out in factory.Yet, can have the situation that need maybe must be independent of any previous analysis and discern the peak value in the frequency domain.For example, in the design phase of new valve actuator, the slip-stick artist may wish new prototype is carried out frequency analysis to guarantee not have in the prototype vibration, resonance and/or the harmonic wave in inherent shortening life-span.Perhaps, frequency analysis can be used as after assembling to be checked instrument before the shipment, whether is manufactured with physical imperfection with some parts of determining mechanical drive system.
Be built in the rotary encoder, or be built in valve actuator or other whirligig or the processor that is associated with valve actuator or other whirligig can be carried out FT.Display, printer or other output unit can merge in the valve actuator, are used for coming display result with the form of chart or figure.Perhaps, the speed data that is produced by fixed timing mark 28 can be sent to the remote computer such as operator PC, speed data being carried out FT and to be shown with more user-friendly form, or transmits data or FT to being positioned at the scene or away from the technician at scene.
Provide more sample can cause finer frequency resolution after speed data is carried out FT.Can obtain the time span of sample or provide more sample by increase by increasing sampling rate.Fig. 8 to Figure 15 shows the curve map of obtaining by with 17 samples of per second that data were produced.Fig. 8 illustrates the utilization frequency analysis resolution of the valve actuator of 128 samples altogether.Fig. 9 is illustrated in the speed data of speed data being carried out FT Fig. 8 before.Figure 10 illustrates the utilization frequency analysis resolution of the valve actuator of 256 samples altogether.Figure 11 is illustrated in the speed data of speed data being carried out FT Figure 10 before.Figure 12 illustrates the utilization frequency analysis resolution of the valve actuator of 512 samples altogether.Figure 13 is illustrated in speed data is carried out the FT speed data of Figure 12 before.Figure 14 illustrates the utilization frequency analysis resolution of the valve actuator of 1024 samples altogether.As shown in the figure, the resolution of frequency analysis increases and improves along with the sample number purpose.
The frequency analysis of any kind as known in the art can be used for the present invention.In described specific embodiment, use to equal 2
nA plurality of samples come speed data is carried out FT, wherein n is any integer.Therefore, the sum of sample for example equals 128,256,512,1024,2048,4096,8192 etc.Therefore, if obtain 3500 samples, so only 2048 samples can be used for FT.In other embodiments, can be to accurately not equaling 2
nSample carry out FT.Yet in those embodiment, leakage may become a concerned issue.Be known in the art the technology that is used to solve leakage.
In addition, in a specific embodiment, FT utilizes at the obtained sample of stable state.Therefore, timing wheel 20 is to rotate relative to constant speed.In the time of in rotary encoder 1 is incorporated in electric driver's valve actuator, timing wheel 20 will quicken and slow down in a period of time.Can before carrying out FT, be carried out truncation (truncate), average (average) or window (window) in speed data and deceleration data that the accelerating period produced.The instantaneous frequency analysis is as known in the art and can be used for substituting the truncation data.
Can carry out truncation to speed data by algorithm, this algorithm was designed to before FT handles the analysis speed data so that remove any expedited data or deceleration data.Perhaps, speed data can be by truncation so that sample number and FT 2
nRequire compatible.
Phrase FT is contained very wide algorithm scope as used herein, comprises Fast Fourier Transform (FFT).FT is contained four big classes of Fourier transform as used herein: continuous fourier transform, Fourier series, discrete time Fourier transform and discrete Fourier transformation.Also there is the FT algorithm that is designed to handle approximate and non-homogeneous data.Discrete Fourier transformation is most commonly used to digital signal processing.Phrase FT is contained any algorithm with the data compatibility that produced as used herein.
Represent the desirable maximum duration that gets sample actuation time.For example, for valve actuator, but valve moves to off-position or moves to the maximum time that the required time of open position is the picking rate data from off-position from open position.Valve only can partly move, and therefore only the part of actuation time can be used for the speed data sampling.An exemplary method that increases the speed data sample that is produced comprises the increase sampling rate.Sampling rate is decided by the speed of timing wheel 20 and the number of fixed timing mark 28.Rotary encoder 1 and 2 sampling rates that can have far above 17 samples p.s..
The other method that increases the data sampler number that is produced is included in collects data a plurality of actuation times.Each new data set can be collected associating with available data, and is enough high to allow utilizing FT that it is operated until the sample counting.In case data set has been expired, then any new data sample the oldest replaceable data sampler is used for analyzing thereby keep up-to-date data set.Can be in such as tables of data storage speed or position data, be used near in real time or frequency-domain analysis subsequently.
Figure 15 provides possible sampling rate and can be used for the table of the gained total number of samples of frequency analysis.In Figure 15, it is the sampling rate of unit that the delta pulse frequency equals with Hz.Speed DS is the transmission speed of the drive socket (DS) of valve actuator.Yet speed DS can be relevant with the rotating member of any device.Awl tooth group speed multiple (Bevel Set Speed Multiplier) expression increases the speed that gear caused that DS is connected to the input shaft that drives wheel for inputting 10.Wheel for inputting 10 speed multiples are illustrated in gear between the pinion wheel 25 of the gear 11 of wheel for inputting 10 and timing wheel 20 to be compared the speed that is caused and increases.
The example of the rotating member of whirligig is the drive socket of valve actuator.Input shaft can interconnect to wheel for inputting 10 with drive socket via awl tooth group.Any connected mode as known in the art can be used for driving wheel for inputting 10.As one of data sampling possible example, if drive socket rotates with 200rpm, and if awl tooth group cause about 4.8: 1 speed to increase, input shaft will rotate with 960rpm so.Therefore, wheel for inputting 10 can rotate with 960rpm.Wheel for inputting 10 driving timing wheel 20.If utilize 51/38 tooth speed-increasing gear (spur increaser), timing wheel 20 rotates with about 1288rpm so.1288rpm is divided by 60 rotations that equal timing wheel 20 per seconds.Exemplary timing wheel 20 shown in Figure 1 has 32 fixed timing marks.Yet iff utilizing 16 fixed timing marks, the rotation of the per second number that multiply by fixed timing mark obtains the sampling rate (delta pulse frequency) of 343 samples of per second so.Under identical situation, if timing wheel 20 has 32 fixed timing marks, sampling rate is about 678 samples of per second so.Nyquist (Nyquist) frequency is 1/2nd of a sampling frequency.It is to equal actuation time of unit the total number of samples that can collect during single complete action that sampling rate multiply by with the second.
Figure 15 shows actuation time and sampling rate influencing each other in the accuracy of calculated rate analysis.Iff short speed data operation is available, and then an alternative will be for lacking the operation gang to improve frequency resolution before data are carried out FT.
Figure 15 uses Hanning window (Hanning Window), to prevent the distortion of the discontinuous frequency values that is caused of rate signal when the beginning of data set and the ending.Other possible window comprises rectangular window, Blackman window (Blackman), Hamming window (Hamming), triumphant damp window (Kaiser), window index and laylight.Yet any window that is known in the art can be used for the estimating speed data.Be known in the art as why not using window to carry out frequency analysis.Any method that being used to of being known in the art carried out frequency analysis can be used for the present invention.
Can on basis one by one, the estimated frequency data determine that peak and amplitude are about the suggested content of valve actuator.Perhaps, frequency analysis can be compared with given frequency analytical characteristic (signature), to determine the health status of valve actuator or other whirligig.
Figure 16 to Figure 19 shows the representative frequency analysis that can be used for comparing.Figure 18 and Figure 19 show the rotational speed that depends on valve actuator or other whirligig substantially and the velocity variations that changes.For the data that produce Figure 16 and Figure 17 in stable state with the actuator of 26 rotations of per minute (rpm) operation.For the data that produce Figure 18 and Figure 19 in stable state with the actuator of 18rpm operation.Figure 16 and Figure 19 and Figure 17 and Figure 18 utilize same-code device pinion wheel adapter respectively.Figure 16 has remarkable peak value at 45.4Hz and 91.1Hz.The remarkable peak value of Figure 19 is more obvious and more.Many problem tunables in valve actuator or other whirligig show as the single peak value of frequency domain.Carry out that frequency analysis can disclose in the single peak value that is hidden in a speed but the potential problems that are rendered as a plurality of peak values in other speed in different operating speed.
Rotary encoder of the present invention is described to many wheel absolute encoders.Rotary encoder also can be single wheel absolute encoder or incremental encoder.For example, timing wheel 20 can be integrated in the wheel identical with wheel for inputting 10.Then, wheel for inputting 10 can play the effect of incremental encoder and timing wheel.And the encoded segment of code wheel 30 to 110 can be integrated in the wheel for inputting 10, as known in the art.Then, wheel for inputting 10 can play the effect of single wheel absolute encoder.Wheel for inputting 10 can be designed to match with the end of input shaft, or alternatively wheel for inputting 10 can be installed on input shaft around, such as longitudinal center at input shaft.Yet wheel for inputting 10 can be installed on any point along the length of input shaft.
Formerly, with respect to speed data frequency analysis has been discussed.Extra data embodiment comprises the moment of torsion data.In the valve actuator of measuring moment of torsion, the vibration of moment of torsion can be transformed into frequency domain.Be delivered in monitoring under the situation of output torque of valve rod, also can in frequency domain, analyze the moment of torsion data.Be incorporated in the processor in the valve actuator or can the moment of torsion data-switching be become frequency domain in any mode in the mode of above being discussed about speed data or by any technology as known in the art away from the processor of valve actuator.Then, can discern the frequency of power train member and the indication of valve actuator health status is provided to the operator.
Another data embodiment comprises the thrust data.For example, the motor of valve actuator is connected to the worm screw of the worm screw/worm gear in the power train.The axial thrust of monitoring worm gear is to read the moment of torsion that is transmitted by worm gear.Merge to the processor in the valve actuator or the thrust data-switching can be become frequency domain away from the processor of valve actuator, be similar to above in the method for discussing about speed data any method or by any technology as known in the art.Can discern the frequency of power train member by operator or computer program.Therefore, the diagnosis of valve actuator is provided.In addition, can utilize a plurality of thrust pickups.
Excessive data embodiment involving vibrations data.For example, eight accelerometers are positioned over a plurality of positions in the valve actuator.All eight accelerometers will read the identical vibration in the valve actuator.Yet the accelerometer of close given vibration source will have stronger signal.Observation can allow to find out vibration source from the vibration data of all eight sensors in the frequency domain.The frequency of vibration can be relevant with the power train member.Therefore, the operator can be warned the imminent problem of any possibility of valve actuator.
Utilize the sensor of arbitrary number in can any embodiment in these embodiments.For example, can utilize speed pickup more than one.In addition, can utilize dissimilar a plurality of sensors.For example, valve actuator can comprise rotary encoder, such as rotary encoder 1.Valve actuator also can comprise the axial thrust sensor.The speed data that can be produced timing wheel 20 is carried out frequency analysis to the thrust data or to the two.
To can drive by motor, hydraulic pressure, engine, handwheel or any other drive unit as known in the art by the whirligig or the valve actuator of the present invention's monitoring.
Although the description of preamble contains many concrete conditions, be not considered to it and limit the scope of the invention, and only provide some one exemplary embodiment.Equally, under the situation that does not depart from the spirit or scope of the present invention, can design other embodiments of the invention.Therefore, scope of the present invention can be only the represented and restriction by the equivalent on appended claims and the legal sense thereof, rather than represented and restriction by the description of preamble.Meaning and interior all interpolations of the present invention, deletion and modification also are covered by among the present invention of scope that belongs to claims disclosed herein.
Claims (14)
1. absolute encoder, it comprises:
Wheel for inputting, it is configured for receiving the rotation input;
Timing wheel, it can produce speed data and be driven by described wheel for inputting;
A plurality of code wheels, it operationally is attached to described timing wheel; With
A plurality of sensors, it is configured for detecting the position of described a plurality of code wheel and described timing wheel, and wherein, each in described a plurality of sensors comprises redundant sensor.
2. absolute encoder according to claim 1 is characterized in that described absolute encoder comprises processor, and it can be operated being transformed into frequency data by the speed data that described timing wheel was produced.
3. absolute encoder according to claim 1 is characterized in that, described a plurality of sensors are selected from optical sensor, hall effect sensor, magnetic sensor or electric contact.
4. absolute encoder according to claim 1 is characterized in that, described a plurality of sensors and described redundant sensor can be worked as when described a plurality of sensor or described redundant sensor are actuated and tested each other.
5. valve actuator, it comprises:
Absolute encoder, it comprises:
At least one scrambler dish;
A plurality of sensors, it can be operated to read described at least one scrambler dish;
Speed pickup, it can be operated to produce speed data; With
At least one repeats sensor, and it is used for described a plurality of sensor and described speed pickup each; With
Be suitable for driving the power train of described absolute encoder.
6. valve actuator according to claim 5 is characterized in that, described valve actuator also comprises the processor that is suitable for producing alarm when the component failure of described absolute encoder.
7. valve actuator according to claim 6 is characterized in that, described processor is suitable for estimating the influence of described component failure to being produced by the indicated position of described absolute encoder.
8. valve actuator according to claim 7 is characterized in that described processor is suitable for cutting out described valve actuator.
9. valve actuator according to claim 7 is characterized in that described processor is suitable for producing alarm.
10. valve actuator according to claim 6 is characterized in that, component failure comprises that in described a plurality of sensor one, described speed pickup or described at least one corresponding one of repeating in sensor can not operate or in the operation of the time of mistake.
11. valve actuator according to claim 6 is characterized in that, described processor also is suitable for producing alarm when indicating uncontinuity in the record at valve position.
12. valve actuator according to claim 5 is characterized in that, described valve actuator also comprises and is suitable for from described speed pickup inbound pacing data and described speed data is carried out the processor of frequency-domain analysis.
13. valve actuator according to claim 12 is characterized in that, described processor is the part of described absolute encoder.
14. valve actuator according to claim 5 is characterized in that, the drive socket of described power train is suitable for driving described absolute encoder.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5640007A (en) * | 1995-06-21 | 1997-06-17 | Limitorque Corporation | Optical encoder comprising a plurality of encoder wheels |
| CN1554151A (en) * | 2001-09-14 | 2004-12-08 | �ʼҷ����ֵ��ӹɷ�����˾ | Encoder redundancy selection system and method |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5640007A (en) * | 1995-06-21 | 1997-06-17 | Limitorque Corporation | Optical encoder comprising a plurality of encoder wheels |
| CN1554151A (en) * | 2001-09-14 | 2004-12-08 | �ʼҷ����ֵ��ӹɷ�����˾ | Encoder redundancy selection system and method |
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