CN1920487A - Optical encoder and control device thereof - Google Patents
Optical encoder and control device thereof Download PDFInfo
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- CN1920487A CN1920487A CN 200510090991 CN200510090991A CN1920487A CN 1920487 A CN1920487 A CN 1920487A CN 200510090991 CN200510090991 CN 200510090991 CN 200510090991 A CN200510090991 A CN 200510090991A CN 1920487 A CN1920487 A CN 1920487A
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Abstract
The invention relates to an optical encoder, and relative controller, wherein the controller is connected to the optical sensing chip, to receive the output signal of chip to judge the displacement of glass plate; and the controller comprises a couple of magnifiers for magnifying the periodical signal at 90 degree phase difference output by the chip, a couple of analogue/digit converters connected to the magnifier couple to convert the output of magnifier into digit signal, a couple of hysteresis comparators connected to the chip to receive the output signal of chip to hysteresis compare; a counter connected to the hysteresis comparators, based on their output to count ascending or descending; and a fixing element for receiving the outputs of converters and counter, to interpolate with inverse trigonometric function, and count the digit signal of hysteresis comparison, to obtain the optical encoded result with high resolution.
Description
Technical field
The present invention relates to a kind of optical encoder and control device thereof, relate in particular to a kind of based on digital signal processor (DSP) thereby, by original analog is carried out interpolation, the digital signal of magnetic hysteresis after relatively counted can be obtained more high-resolution optical encoder and control device thereof simultaneously with the inverse trigonometric function formula.
Background technology
Comprise an optical encoder in the AC servomotor, this optical encoder provides the angle of rotor to produce corresponding electromagnetic field for the stator switch current.Servo motor is installed on the application device, realizes locating or controlling the demand of speed.Optical encoder provides accurately more, and the location will be accurate more, and noise also can be more little.But the mode that the product of market circulation is at present done interpolation with permanent circuit has reached the limit.
With traditional raster type scrambler, the method for common increase resolution has three kinds.One, increases code-wheel bar code number; Two, electronic features is cut apart; Three, adopt different optical principles.Wherein method one is subject to manufacturing process and diffraction phenomena, and the resolution of its increase is limited; Method two need not change the body framework, and the method for its application is more, and along with the lifting of electronic signal process speed, its increasable resolution can also increase; Method three needs to change original framework, is used laser diode and suitable light path design, and applied optics diffraction or principle of interference are to realize increasing the demand of resolution.
Cut product from existing optical encoder segmentation, but summary is distinguished into four kinds of forms: one, be contained in the scrambler, as GPI 9220, DRC 25D, RSF MS 6X series; Two, product independently, as Reinshaw (RENISHAW) RGE series, HEIDENHAIN EXE 605 and the MJ100/110 of Sony, MJ500/600/700 series interpolation module; Three, depend in control card or the other products, as MMI200-PC/104; Four, be integrated in the motor, as Fanuc, Mitsubishi (Mitsubishi).The resolution that technology is cut in segmentation is from 4 times to 2048 times commonly used, even higher multiple, and its fiduciary level depends on the quality of original signal and the compensation technique of signal mostly, and accessible resolution then is subject to the principle of use.
Generally speaking, under the identical situation of signal quality, the original input signal that segmentation is cut is simulating signal (a string ripple), cooperates digital processing more easily to obtain high power and cuts apart number.
Segmentation is cut principle and can be divided into phase subdivision method and amplitude close classification, can be divided into following several according to function and feature:
One, direct close classification:
Quadruple method (as shown in Figure 1) just, general servomotor drive often provides this function.It mainly utilizes the A, B signal of scrambler to cooperate application-specific integrated circuit, PAL or GAL can realize that quadruple cuts apart.
Two, resistance chain phase shift close classification:
The method is to utilize the A of similar string ripple, B signal to cooperate resistance chain to cause to differ, and uses suitable again and subtractive combination, makes original signal be divided into the n equal portions.This method is cut apart carefully more, and required resistance quantity is just many more, and the requirement of the precision of resistance also improves relatively.Common segmentation number is about 20.
Three, resistance chain array mode, it can be in parallel or the mode (as shown in Figure 2) of series connection.Class string ripple signal by A, B output can be expressed as:
A＝U
0sinα
B＝U
0cosα
Signal through the resistance chain combination can be expressed as:
U
i＝Acosβ
i+Bsinβ
i
＝U
0(cosβ
isinα+sinβ
icosα)
＝U
0sin(α+β
i)
β
i＝i*360°/n i＝1，2，3，4.....
A, B two phase signals are the signals that differ 90 degree, can be expressed as two quadratures vector (V1, V2), the signal V of tap therefrom
KCan be expressed as:
For example United States Patent (USP) is exactly an example of using the resistance chain technology No. 5920494, but this patent proposed a kind of multistage (1X, 2X, 5X, thus 10X) method that guarantees not miss pulse number between switching is cut in segmentation.
Four, amplitude close classification:
As the term suggests being the amplitude with A, B signal, the method is divided into the n equal portions.Referring to Fig. 3, United States Patent (USP) utilizes the different A of several amplitudes, B signal subtraction No. 6355927, relatively realizes the effect of segmentation again by logic.
Five, the A/D close classification of tabling look-up:
With resistance chain phase shift close classification is example, cut apart multiple and be at 20 o'clock and will use 120 resistance and 40 comparers, it is big more to cut apart number, then required assembly will be many more, the precision of assembly also needs to improve relatively, arise at the historic moment in the method that is to use ADC (analog-digital converter), the value of removing of A, B phase signals can be obtained present angle via the applications of electronic circuitry Taylor series expansion again.But in order to reduce operation time, the ROM that often arranges in pairs or groups realizes (referring to Fig. 4) with lookup table mode.
Six, electronic operation close classification:
Along with development of science and technology, the arithmetic speed of DSP and MPU (microprocessor) constantly promotes, and for meeting the diversified demand of high speed, the high at a high speed ADC of parsing cooperates the segmentation technology of cutting of DSP or MPU constantly to weed out the old and bring forth the new.Along with several increases is cut in segmentation, the quality requirements of original signal is higher, therefore need adjust signal actively or passively.This compensation technique comprises the orthogonality adjustment of signal amplitude, the accurate position of DC and signal usually.If DSP or MPU also are used for servocontrol simultaneously, in order to alleviate its computational burden, the calculation process of part also can be arranged in pairs or groups and be tabled look-up or electronic circuit is realized.
The example that Fig. 5 cuts for the electronic operation segmentation, adopt the parallel processing framework, ADC resolution is 12bit, be used to provide the foundation of angle computing, phase digitization device (phase digitizer) is 3bit, cooperate the high speed signal handling part to assign to produce N and PH, the information that quadrant and comparison are provided is to the DSP reference.PH is 1 when M is 0,1,2,3, and PH is 0 when M is 4,5,6,7, when M when 7 become 0, N increases by 1.
Yet above-mentioned various known optical encoder can't solve high speed issue of resolving under requiring, and promptly can't effectively use the arithmetic capability of existing digital signal processor and reach more performance.
Summary of the invention
Therefore one object of the present invention is to provide a kind of based on digital signal processor, by thereby original analog is carried out interpolation, the digital signal of magnetic hysteresis after relatively counted obtained more high-resolution optical encoder and control device thereof simultaneously with the inverse trigonometric function formula.
To achieve these goals, the invention provides a kind of optical encoder and control device thereof.The control device of this optical encoder is electrically connected to optical sensing chip, and the output signal that can receive optical sensing chip is to judge the displacement information of glass sheet.Wherein, control device comprises: a pair of analogue amplifier, can amplify the periodic signal of spending from the phase phasic difference 90 of optical sensing chip output; A pair of analog-digital converter, it is right that it is electrically connected to analogue amplifier, converts digital signal to the output with analogue amplifier; A pair of hysteresis comparator, it is electrically connected to optical sensing chip, and the output signal that can receive optical sensing chip is to make magnetic hysteresis relatively; Counter, it is right that it is electrically connected to hysteresis comparator, can count up or down according to the output of hysteresis comparator; And firmware unit, can receive analog-digital converter to and the output of counter, can carry out interpolation by the inverse trigonometric function formula, simultaneously the digital signal of magnetic hysteresis after relatively counted, thereby can be obtained more high-resolution optical encoding result.
Description of drawings
Fig. 1 is the frequency-doubled signal key diagram;
Fig. 2 is a resistance chain phase shift close classification synoptic diagram;
Fig. 3 is an amplitude close classification oscillogram;
Fig. 4 is the close classification synoptic diagram of tabling look-up;
Fig. 5 cuts the prior art block scheme for the electronic operation segmentation;
Fig. 6 is the synoptic diagram according to the optical encoder of the preferred embodiment of the present invention;
Fig. 7 is the block scheme according to the control device of the preferred embodiment of the present invention;
Fig. 8 is the operational flowchart of firmware unit in the control device of the present invention.
In the accompanying drawing, the list of parts of each label representative is as follows:
10-optical encoder 100-control device
The 110A-first analogue amplifier 110B-second analogue amplifier
The 120A-first hysteresis comparator 120B-second hysteresis comparator
120C-the 3rd hysteresis comparator
The 150A-first analog-digital converter 150B-second analog-digital converter
160-counter 170-firmware unit
200-people having the same aspiration and interest light source 210-glass sheet
220-light shield sheet 240-optical sensing chip
Embodiment
In order to make those skilled in the art further understand feature of the present invention and technology contents, see also following about detailed description of the present invention and accompanying drawing, accompanying drawing only provide with reference to and usefulness is described, be not to be used for limiting the present invention.
Referring to Fig. 6, be synoptic diagram according to the optical encoder 10 of the preferred embodiment of the present invention.Optical encoder 10 comprises people having the same aspiration and interest light source 200 (for example being laser lamp), has glass sheet 210, light shield sheet 220, optical sensing chip 240 and control device 100 (not shown) of etching mark.Glass sheet 210 has the glass sheet of 2500 scales for a for example circle, and behind rotation one circle, optical sensing chip 240 can produce the 90 ° of sinusoidal signals that differ of 2500 A, B phase.
Referring to Fig. 7, be block scheme according to the control device 100 of the preferred embodiment of the present invention.Control device 100 can receive the signal that is detected from optical sensing chip 240 and be handled, to obtain the displacement data of glass sheet 210.Control device 100 comprises the first analogue amplifier 110A and the second analogue amplifier 110B, the first hysteresis comparator 120A that is connected to optical sensing chip 240, the second hysteresis comparator 120B and the 3rd hysteresis comparator 120C that is connected to optical sensing chip 240.In addition, control device 100 also comprises the first analog-digital converter 150A and the second analog-digital converter 150B that is connected respectively to the first analogue amplifier 110A and the second analogue amplifier 110B, the firmware unit 170 that is connected to the counter 160 of the first hysteresis comparator 120A and the second hysteresis comparator 120B and is connected to the output of the first analog-digital converter 150A, the second analog-digital converter 150B, counter 160 and the 3rd hysteresis comparator 120C.
Wherein, it is 90 ° A, B phase signals (sine and cosine signal) that the first analogue amplifier 110A and the second analogue amplifier 110B receive respectively from differing of optical sensing chip 240 output, that is:
A＝U
0sinθ
B＝U
0cosθ
In addition, A, B phase signals via the first analogue amplifier 110A and the second analogue amplifier 110B processing and amplifying can be respectively via being sent to firmware unit 170 again after the first analog-digital converter 150A and the second analog-digital converter 150B digitizing, to carry out process of frequency multiplication.
By following formula, the mode that θ can table look-up obtains, but since cycle of tan θ be π, from-pi/2 to pi/2, by the signal A of the first hysteresis comparator 120A and second hysteresis comparator 120B output
p, B
p(as shown in Figure 6) can carry out four and cut apart, thus the interval that draws θ at which quadrant, A simultaneously
p, B
pAfter digital signal enters counter 160, can carry out the counting of pulse wave.Suppose that glass sheet 210 has 2500ppr A, the B phase, presentation code device 10 can provide every circle that the parsing of 2500ppr*4=10000ppr is arranged.If
Table make up from 0～pi/2, be divided into 180 lattice, so whole synthetic resolution will reach 1800000ppr.
In block scheme shown in Figure 7, the height of scrambler is resolved the problem that requires to be mainly used to solve slow-revving location resolution and velocity estimation.Through hysteresis comparator and quadruple method, can obtain waveform as shown in Figure 1, that is to say after rotation one is enclosed to have 2500 * 4 pulse waves.10000ppr is enough for high-revolving estimation, but can produce staircase for slow-revving estimation, thereby causes the sudden change of electric current.In order to increase parsing, must handle with 90 ° the sinusoidal signal of differing of the output A of optical sensing chip, B phase, the work of this part can be finished by the first analogue amplifier 110A, the second analogue amplifier 110B, the first analog-digital converter 150A and the second analog-digital converter 150B.In addition, can realize that in the first analog-digital converter 150A shown in Fig. 7 right side, the second analog-digital converter 150B, counter 160 and firmware unit 170 arithmetic capability of utilizing digital signal processor is to realize more performance by digital signal processor.
Referring to Fig. 8, be the operational flowchart of firmware unit 170 in the control device 100 of the present invention.Firmware unit 170 triggers (step 100) at Fixed Time Interval, and reads the output (step 102) of counter 160 and judge whether the output of counter 160 changes (step 104).If the output of counter 160 changes, the output Cu that then sets counter 160 is present count value n, and the quadrant angle of θ is made zero, i.e. Cd=0 (step 120).If the output of counter 160 does not change, then the output result by the first analog-digital converter 150A and the second analog-digital converter 150B can obtain angle θ (step 110), then the signal A that exports by the first hysteresis comparator 120A and the second hysteresis comparator 120B
p, B
pQuadrant that can angle correction θ, i.e. Cd=θ/90 (steps 112).Last counter 160 output Cu, Cd send it to firmware unit 170 to judge the shift position of glass sheet 210.
The above only is the preferred embodiments of the present invention, be not so promptly limit claim of the present invention, the equivalent transformation that every utilization instructions of the present invention and accompanying drawing content are done, or directly or indirectly be used in other relevant technical field, all in like manner be included in the claim of the present invention.
Claims (10)
1. optical encoder comprises:
Light source;
The glass sheet that the etching mark is arranged;
Optical sensing chip, it receives the result of described light source irradiation to described glass sheet, to produce the periodic signal of phase phasic difference 90 degree; And
Control device, it is electrically connected to described optical sensing chip, and the output signal that receives described optical sensing chip is to judge the displacement information of described glass sheet, and wherein said control device comprises:
A pair of analogue amplifier, it will amplify from the periodic signal that the described phase phasic difference 90 of described optical sensing chip output is spent;
A pair of analog-digital converter, it is right that it is electrically connected to described analogue amplifier, converts digital signal to the output with described analogue amplifier;
A pair of hysteresis comparator, its output signal that is electrically connected to described optical sensing chip and receives described optical sensing chip is to carry out magnetic hysteresis relatively;
Counter, it is right that it is electrically connected to described hysteresis comparator, counts up or down according to the output of described hysteresis comparator; And
Firmware unit, its receive described analog-digital converter to the output of described counter, to obtain the displacement information of described glass sheet.
2. optical encoder as claimed in claim 1, wherein, the periodic signal of described phase phasic difference 90 degree is sinusoidal signal and cosine signal.
3. optical encoder as claimed in claim 1, wherein, described firmware unit according to described analog-digital converter right output carry out process of frequency multiplication.
4. optical encoder as claimed in claim 1, wherein, right output obtains the angle θ of displacement information to described firmware unit according to described analog-digital converter.
5. optical encoder as claimed in claim 4, wherein, right output determines the angle θ of described displacement information at which quadrant to described optical encoder according to described hysteresis comparator.
6. the control device of an optical encoder, it handles the output signal from optical sensing chip, and described optical sensing chip receives the result of light source irradiation to the glass sheet that the etching mark is arranged, and to produce the periodic signal that phase phasic difference 90 is spent, described control device comprises:
A pair of analogue amplifier, it will amplify from the periodic signal that the described phase phasic difference 90 of described optical sensing chip output is spent;
A pair of analog-digital converter, it is right that it is electrically connected to described analogue amplifier, converts digital signal to the output with described analogue amplifier;
A pair of hysteresis comparator, it is electrically connected to described optical sensing chip, and the output signal that receives described optical sensing chip is to make magnetic hysteresis relatively;
Counter, it is right that it is electrically connected to described hysteresis comparator, counts up or down according to the output of described hysteresis comparator; And
Firmware unit, its receive described analog-digital converter to the output of described counter, to obtain the displacement information of described glass sheet.
7. the control device of optical encoder as claimed in claim 6, wherein, the periodic signal of described phase phasic difference 90 degree is sinusoidal signal and cosine signal.
8. the control device of optical encoder as claimed in claim 6, wherein, described firmware unit according to described analog-digital converter right output carry out process of frequency multiplication.
9. the control device of optical encoder as claimed in claim 6, wherein, right output obtains the angle θ of displacement information to described firmware unit according to described analog-digital converter.
10. the control device of optical encoder as claimed in claim 9, wherein, right output determines the angle θ of described displacement information at which quadrant to described optical encoder according to described hysteresis comparator.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510090991 CN1920487A (en) | 2005-08-22 | 2005-08-22 | Optical encoder and control device thereof |
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|---|---|---|---|
| CN 200510090991 CN1920487A (en) | 2005-08-22 | 2005-08-22 | Optical encoder and control device thereof |
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|---|---|
| CN1920487A true CN1920487A (en) | 2007-02-28 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111135481A (en) * | 2020-01-22 | 2020-05-12 | 哈尔滨理工大学 | Chest and abdomen surface respiratory motion signal phase error super-resolution method |
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2005
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111135481A (en) * | 2020-01-22 | 2020-05-12 | 哈尔滨理工大学 | Chest and abdomen surface respiratory motion signal phase error super-resolution method |
| CN111135481B (en) * | 2020-01-22 | 2021-09-07 | 哈尔滨理工大学 | Chest and abdomen surface respiratory motion signal phase error super-resolution method |
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