JP4768164B2 - Rotary encoder device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary encoder device, and more particularly, to a rotary encoder device capable of accurately correcting an angle measurement result and detecting a rotation angle with high accuracy even when an encoder wheel is eccentric.
[0002]
[Prior art]
Conventional rotary encoder devices are assembled with a robust housing and precise position adjustment to prevent errors due to eccentricity, and are very expensive.
[0003]
Therefore, recently, a rotary encoder device called a modular type has been provided in which a rotary scale and a detection head are separated and a user can assemble them using a jig so as to reduce costs. In the case of incorporating into a device of this type, the precise adjustment of the rotary scale and the adjustment result in a problem that the operation cost becomes high and the cost of the device becomes high.
[0004]
In view of this, there has conventionally appeared an encoder apparatus in which two detection heads are mounted with a 180.degree. Shift, and ½ of the sum of the respective measurement angles is calculated (see JP-A-7-140844, etc.).
[0005]
[Problems to be solved by the invention]
However, in such a conventional rotary encoder device, two detection heads are mounted with a 180 ° shift, and by calculating half the sum of the respective measurement angles, the rotary body of the rotary encoder device is Although we are trying to eliminate the mounting error and rotation signal unevenness and to accurately detect the angular velocity, the cost of the rotary encoder device increases due to the use of two expensive detection heads. There is a problem that the price of equipment to which the rotary encoder device is applied increases.
[0006]
Therefore, the present invention corrects the eccentricity of the encoder wheel with a single detection head, does not require precise adjustment for the encoder wheel, and is capable of detecting a rotational angle with high accuracy at a low cost. An object is to provide an encoder device.
[0007]
  Specifically, the invention according to claim 1 is directed to a rotating detection scale formed of a diffraction grating and extending in a radial direction at a constant angle or a predetermined angle in a circumferential direction on a rotating encoder wheel; Are formed concentrically with an eccentricity detection scale consisting of a diffraction grating, and the rotation detection scale and the eccentricity detection scale are irradiated with coherent light as detection light from the light irradiation means, and the detection means is irradiated from the light irradiation means. In addition to detecting the interference fringes diffracted by the rotation detection scale and outputting the rotation signal indicating the rotation amount of the encoder wheel, the interference fringes diffracted by the eccentricity detection scale are detected and the eccentric signal indicating the eccentricity amount of the encoder wheel is output.Then, the pulsing means converts the rotation signal output from the detection means into a rotation pulse signal, and the eccentric signal adjustment means converts the eccentric signal output from the detection means into an eccentric pulse signal corresponding to the amount of eccentricity. In the adjusting means, the eccentric pulse signal output from the eccentric signal adjusting means is converted into the pulse width of the eccentric amount with respect to the pulse width of the rotation pulse signal output from the pulsing means by converting the eccentric amount indicated by the eccentric pulse signal to the pulse width. Adjusts the pulse width of the rotation pulse signal output by the pulse generatorBy doing so, the eccentric amount of the encoder wheel is detected simultaneously with the rotation angle of the encoder wheel without disposing a detector at a position opposite to 180 ° as in the prior art, and the angle measurement result is corrected by the eccentric amount, Rotational angle can be measured inexpensively and with high accuracyIn addition, it is possible to perform counting and angle calculation with an encoder circuit that is generally used by using a rotation signal that has already been corrected for eccentricity, making it easier to use an inexpensive and high-precision rotation signal, and making it easier to use. Can improveAn object is to provide a rotary encoder device.
[0008]
  The invention according to claim 2A rotation detection scale made of a diffraction grating and formed in a rotating encoder wheel extending in the radial direction at a constant angle or a predetermined angle in the circumferential direction, and an eccentricity detection scale made of a diffraction grating concentrically in the circumferential direction. The coherent light is irradiated as detection light from the light irradiation means to the rotation detection scale and the eccentric detection scale, and the detection means detects the interference fringes emitted from the light irradiation means and diffracted by the rotation detection scale. Outputs a rotation signal indicating the amount of rotation of the encoder wheel, detects interference fringes diffracted by the eccentricity detection scale, outputs an eccentricity signal indicating the amount of eccentricity of the encoder wheel, and outputs the rotation output from the detection means by the pulsing means The signal is converted into a rotation pulse signal, and the rotation pulse width conversion means converts the rotation pulse signal output from the pulsing means into a narrow rotation pulse with a predetermined short pulse width. The eccentric signal adjusting means converts the eccentric signal output from the detecting means into an eccentric pulse signal corresponding to the eccentric amount, and the eccentric rotating pulse generating means outputs the eccentric pulse signal output from the eccentric signal adjusting means. Is converted into a rotated eccentric pulse signal every time the amount of eccentricity indicated by the eccentric pulse signal corresponds to one pulse of the narrow width rotation pulse signal output from the rotation pulse width conversion means, and the rotation pulse width conversion means is converted by the pulse addition means. Is added to the rotation eccentricity pulse signal generated by the rotation eccentricity pulse generating means and output as an eccentricity adjustment rotation signal. Without installation, the encoder wheel rotation angle is detected at the same time as the encoder wheel rotation angle, and the angle measurement result is corrected with the eccentricity amount. Can measure the angle of rotation,Counting and angle calculation is possible with encoder circuits that are generally used using rotation signals that have already been corrected for eccentricity, making it easier to use inexpensive and high-precision rotation signals and improving usability. It aims at providing the rotary encoder apparatus which can be used.
[0010]
  Claim3In the described invention, the light irradiating means is provided with one light source, and provided with light splitting means for dividing the light from the light source into rotation detection detection light and eccentricity detection detection light, and the rotation detection detection light is rotated. Providing a rotary encoder device that can enter a detection scale and make the eccentricity detection detection light incident on the eccentricity detection scale, thereby reducing the number of expensive light sources and performing measurement at a lower cost and with higher accuracy. It is aimed.
[0011]
  Claim4The invention described is provided with an error discriminating unit that discriminates an attachment error of the detecting unit or the encoder wheel based on an eccentric signal output from the detecting unit and outputs an error signal indicating an error discriminating result. It is an object of the present invention to provide a rotary encoder device that makes it possible to easily recognize the mounting error, improve the workability of the mounting work, and improve the usability.
[0012]
[Means for Solving the Problems]
  The rotary encoder device according to the first aspect of the present invention is a rotation detection scale formed of a diffraction grating and extending in the radial direction at a constant angle or a predetermined angle in the circumferential direction,as well as,An eccentricity detection scale consisting of a diffraction grating concentrically formed in the circumferential directionLeAn encoder wheel that is formed and rotated, a light irradiation means that irradiates the rotation detection scale and the eccentricity detection scale with coherent light as detection light, and an interference fringe that is irradiated from the light irradiation means and diffracted by the rotation detection scale. Detecting means for detecting and outputting a rotation signal indicating the amount of rotation of the encoder wheel, and detecting an interference fringe diffracted by the eccentricity detection scale and outputting an eccentric signal indicating the amount of eccentricity of the encoder wheel;Pulse converting means for converting a rotation signal output from the detection means into a rotation pulse signal, eccentric signal adjustment means for converting an eccentric signal output from the detection means into an eccentric pulse signal corresponding to an eccentric amount, and the eccentric signal adjustment The eccentric pulse signal output from the means is converted into the pulse width of the eccentric amount with respect to the pulse width of the rotation pulse signal output from the pulsing means by converting the eccentric amount indicated by the eccentric pulse signal, and the output of the pulsing means with the pulse width. Rotation signal adjusting means for adjusting the pulse width of the rotation pulse signal to beBy providing the above, the above object is achieved.
[0013]
  According to the above configuration, the rotation encoder scale formed of the diffraction grating is formed to extend in the radial direction at a constant angle or a predetermined angle in the circumferential direction on the rotating encoder wheel, and the diffraction is formed concentrically in the circumferential direction. An eccentricity detection scale composed of a grating is formed, and the rotation detection scale and the eccentricity detection scale are irradiated with coherent light as detection light from the light irradiation means, and are emitted from the light irradiation means by the detection means and diffracted by the rotation detection scale. Detects interference fringes and outputs a rotation signal indicating the amount of rotation of the encoder wheel, and detects interference fringes diffracted by the eccentricity detection scale and outputs an eccentric signal indicating the amount of eccentricity of the encoder wheelThen, the pulsing means converts the rotation signal output from the detection means into a rotation pulse signal, and the eccentric signal adjustment means converts the eccentric signal output from the detection means into an eccentric pulse signal corresponding to the amount of eccentricity. In the adjusting means, the eccentric pulse signal output from the eccentric signal adjusting means is converted into the pulse width of the eccentric amount with respect to the pulse width of the rotation pulse signal output from the pulsing means by converting the eccentric amount indicated by the eccentric pulse signal to the pulse width. Adjusts the pulse width of the rotation pulse signal output by the pulse generatorAs a result, the encoder wheel eccentricity is detected at the same time as the encoder wheel rotation angle, and the angle measurement result is corrected with the eccentricity without providing a detector at a position opposite to 180 ° as in the prior art. In addition, the rotation angle can be measured with high accuracy,In addition, counting and angle calculation can be performed with an encoder circuit that is generally used by using a rotation signal that has already been corrected for eccentricity, making it easier to use an inexpensive and high-accuracy rotation signal, thereby improving usability. Can be improved.
[0014]
  A rotary encoder device according to a second aspect of the present invention is a rotation detection scale formed of a diffraction grating that extends in the radial direction at a constant angle or a predetermined angle in the circumferential direction, and is formed concentrically in the circumferential direction. And an encoder wheel that is rotated by forming an eccentricity detection scale composed of a diffraction grating, a light irradiation means for irradiating coherent light as detection light to the rotation detection scale and the eccentricity detection scale, and the light irradiation means that is irradiated with the light irradiation means. Detecting the interference fringes diffracted by the rotation detection scale and outputting a rotation signal indicating the rotation amount of the encoder wheel, and detecting the interference fringes diffracted by the eccentricity detection scale and indicating the eccentricity amount of the encoder wheel Detecting means for outputting the pulse, pulsing means for converting the rotation signal output from the detection means into a rotation pulse signal, and the pulse A rotation pulse width conversion means for converting the rotation pulse signal output from the conversion means into a narrow rotation pulse signal having a predetermined short pulse width, and the eccentric signal output from the detection means is converted into an eccentric pulse signal corresponding to the amount of eccentricity. The eccentric signal adjusting means and the eccentric pulse signal output from the eccentric signal adjusting means rotate every time the eccentric amount indicated by the eccentric pulse signal corresponds to one pulse of the narrow width rotation pulse signal output from the rotation pulse width conversion means. Rotating eccentric pulse generating means for converting to a rotating eccentric pulse signal, and adding a thin rotating pulse signal output from the rotating pulse width converting means to the rotating eccentric pulse signal generated by the rotating eccentric pulse generating means. The above object is achieved by providing pulse addition means for outputting as an adjusted rotation signal.
[0015]
  According to the above configuration,A rotation detection scale made of a diffraction grating and formed in a rotating encoder wheel extending in the radial direction at a constant angle or a predetermined angle in the circumferential direction, and an eccentricity detection scale made of a diffraction grating concentrically in the circumferential direction. The coherent light is irradiated as detection light from the light irradiation means to the rotation detection scale and the eccentric detection scale, and the detection means detects the interference fringes emitted from the light irradiation means and diffracted by the rotation detection scale. Outputs a rotation signal indicating the amount of rotation of the encoder wheel, detects interference fringes diffracted by the eccentricity detection scale, outputs an eccentricity signal indicating the amount of eccentricity of the encoder wheel, and outputs the rotation output from the detection means by the pulsing means The signal is converted into a rotation pulse signal, and the rotation pulse width conversion means converts the rotation pulse signal output from the pulsing means into a narrow rotation pulse with a predetermined short pulse width. The eccentric signal adjusting means converts the eccentric signal output from the detecting means into an eccentric pulse signal corresponding to the eccentric amount, and the eccentric rotating pulse generating means outputs the eccentric pulse signal output from the eccentric signal adjusting means. Is converted into a rotated eccentric pulse signal every time the amount of eccentricity indicated by the eccentric pulse signal corresponds to one pulse of the narrow width rotation pulse signal output from the rotation pulse width conversion means, and the rotation pulse width conversion means is converted by the pulse addition means. Are added to the rotation eccentricity pulse signal generated by the rotation eccentricity pulse generation means and output as an eccentricity adjustment rotation signal. Without setting, the encoder wheel's rotation angle is detected at the same time as the encoder wheel's rotation angle, and the angle measurement result is corrected with the eccentricity amount. Can be measured, andCounting and angle calculation is possible with encoder circuits that are generally used using rotation signals that have already been corrected for eccentricity, making it easier to use inexpensive and high-precision rotation signals and improving usability. be able to.
[0018]
  Also,For example, claims3As described in the above, the rotary encoder device includes a light splitting unit that splits the light from the light source into a rotation detection detection light and an eccentricity detection detection light. The rotation detection detection light may be incident on the rotation detection scale, and the eccentricity detection detection light may be incident on the eccentricity detection scale.
[0019]
According to the above configuration, the light irradiating means is provided with one light source, the light splitting means for dividing the light from the light source into the rotation detection detection light and the eccentricity detection detection light, and the rotation detection detection light. Since it is incident on the rotation detection scale and the detection light for detecting the eccentricity is incident on the eccentricity detection scale, an expensive light source can be reduced, and much more inexpensive and highly accurate measurement can be performed.
[0020]
  Also, for example, the claim4As described in the above, the rotary encoder device determines an attachment error of the detection unit or the encoder wheel based on an eccentric signal output from the detection unit, and outputs an error signal indicating an error determination result May be provided.
[0021]
According to the above configuration, since the error determination means for determining an attachment error of the detection means or the encoder wheel based on the eccentric signal output from the detection means and outputting an error signal indicating the error determination result is provided, the detection means or The encoder wheel mounting error can be easily recognized, and the workability of the mounting work can be improved, thereby further improving the usability.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail based on the accompanying drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description which limits, it is not restricted to these aspects.
[0023]
FIGS. 1-5 is a figure which shows 1st Embodiment of the rotary encoder apparatus of this invention, FIG. 1 is the rotary encoder apparatus 1 which applied 1st Embodiment of the rotary encoder apparatus of this invention. FIG.
[0024]
In FIG. 1, the rotary encoder device 1 includes an encoder wheel 2, a rotation detector 3, an eccentricity detector 4, and the like.
[0025]
The encoder wheel 2 is formed in a disk shape. The encoder wheel 2 includes a rotation detection scale 10 made of a diffraction grating, an eccentricity detection scale 11 made of a diffraction grating concentrically formed in the circumferential direction of the encoder wheel 2, and Is formed.
[0026]
The rotation detection scale 10 is for detecting the rotation angle of the encoder wheel 2 and is a diffraction grating that extends in the radial direction and is thin, and is formed as a scale at a constant angle or a predetermined angle.
[0027]
The eccentricity detection scale 11 is for detecting the eccentricity of the encoder wheel 2 and is a diffraction grating formed concentrically in the circumferential direction of the encoder wheel 2 that is the rotation direction of the rotation detection scale 10.
[0028]
As the rotation detection scale 10 and the eccentricity detection scale 11, for example, as shown in FIG. 2, a so-called relief type diffraction grating in which irregularities are formed in the scale portion of the encoder wheel 2 may be used. As shown, the encoder wheel 2 may be of a so-called volume type in which portions having different refractive indexes are provided.
[0029]
The encoder wheel 2 can be used in various forms generally used in a rotary encoder device. For example, the encoder wheel 2 is obtained by processing a rotation detection scale 10 and an eccentricity detection scale 11 by etching a metal plate, and patterning the rotation detection scale 10 and the eccentricity detection scale 11 by using a semiconductor process on a metal film on glass. Various forms are used, such as a pattern in which the rotation detection scale 10 and the eccentricity detection scale 11 are printed on a transparent substrate, and a photoemulsion film formed by photographic exposure and development to form the rotation detection scale 10 and the eccentricity detection scale 11. be able to.
[0030]
In addition, the rotary encoder device 1 according to the present embodiment is characterized in that an eccentricity detection scale 11 for detecting eccentricity is formed, so that the material, shape, and the like of the encoder wheel 2 are limited at all. is not.
[0031]
For example, even a slit that is simple and inexpensive and has a slit shape formed with a pitch of several tens of μm or less can be used because light diffraction occurs.
[0032]
The rotation detection unit 3 includes a rotation detection light source unit (light irradiation unit) 12 and a rotation detection light detector (detection unit) 13, and the eccentricity detection unit 4 includes an eccentricity detection light source unit (light irradiation unit) 14. An eccentricity detection photodetector (detection means) 15 is provided.
[0033]
The rotation detection unit 3 and the eccentricity detection unit 4 can use the same configuration. For example, as shown in FIG. 4, the rotation detection unit 3 and the eccentricity detection unit 4 include a light source 16 and a lens 17 and include a rotation detection photodetector 13. A mask 18 is disposed in front of the decentering detection photodetector 15.
[0034]
The rotation detection light source unit 12 emits light from the light source 16, collects the light emitted from the light source 16 with the lens 17 slightly before the rotation detection scale 10 of the encoder wheel 2, and detects rotation detection light. The device 13 is disposed on the optical axis of the light emitted from the rotation detection light source unit 12 with the encoder wheel 2 interposed therebetween. The detection light emitted from the rotation detection light source unit 12 and collected in front of the rotation detection scale 10 of the encoder wheel 2 passes through and diffracts the rotation detection scale 10 which is a diffraction grating and interferes with each other, resulting in interference fringes. Arise.
[0035]
The mask 18 is a slit mask having the same cycle as the interference fringes, and the rotation detection photodetector 13 detects the light that has passed through the mask 18 and outputs a rotation signal.
[0036]
The eccentricity detection light source unit 14 emits light from the light source 16, collects the light emitted from the light source 16 with the lens 17 slightly before the eccentricity detection scale 11 of the encoder wheel 2, and detects rotation detection light. The device 15 is disposed on the optical axis of the light emitted from the eccentricity light source unit 14 with the encoder wheel 2 interposed therebetween. The detection light emitted from the eccentricity detection light source unit 14 and collected in front of the eccentricity detection scale 11 of the encoder wheel 2 is transmitted through and diffracted by the eccentricity detection scale 11 that is a diffraction grating and interferes with each other, resulting in interference fringes. Arise.
[0037]
The mask 18 is a slit mask having the same cycle as that of the interference fringes, and the eccentricity detection photodetector 15 detects the light that has passed through the mask 18 and outputs an eccentricity signal.
[0038]
Next, the operation of the present embodiment will be described. In the rotary encoder device 1 of the present embodiment, an eccentricity detection scale 11 is formed on the encoder wheel 2, the eccentricity detection unit 4 detects the amount of eccentricity of the encoder wheel 2, and the detection signal of the rotation detection unit 3 is corrected. The feature is that the rotation angle of the encoder wheel 2 is detected with high accuracy.
[0039]
That is, the rotary encoder device 1 condenses the light emitted from the light source 16 of the rotation detection unit 3 in front of the rotation detection scale 10 of the encoder wheel 2 by the lens 17 and forms the light on the rotation detection scale 10 of the encoder wheel 2. The rotation detection photodetector 13 detects the diffracted light that has passed through the rotation detection scale 10 formed by a diffraction grating and passed through the mask 18 that is a slit mask having the same period of interference fringes generated by diffraction. The rotation detection photodetector 13 outputs a rotation signal as shown in FIG. 5 per one rotation of the encoder wheel 2 in accordance with the light transmitted through the rotation detection scale 10 of the encoder wheel 2.
[0040]
On the other hand, the rotary encoder device 1 condenses the light emitted from the light source 16 of the eccentricity detection unit 4 in front of the eccentricity detection scale 11 of the encoder wheel 2 by the lens 17 to the eccentricity detection scale 11 part of the encoder wheel 2. The diffracted light that has been irradiated, passed through the eccentricity detection scale 11 formed of a diffraction grating, and passed through the mask 18 that is a slit mask having the same period of interference fringes generated by diffraction is detected by the eccentricity detection photodetector 15. The eccentricity detection photodetector 15 outputs a rotation signal as shown in FIG. 5 per one rotation of the encoder wheel 2 in accordance with the light transmitted through the eccentricity detection scale 11 of the encoder wheel 2.
[0041]
At this time, if the rotation speed of the encoder wheel 2 is constant, the rotation signal becomes a sinusoidal signal with a constant interval as shown in FIG. 5, and the eccentric signal has an eccentric component by one rotation of the encoder wheel 2. Since this is one cycle, when the encoder wheel 2 rotates once, a number of signals corresponding to the amount of eccentricity are output. The fluctuation of the eccentric signal at this time changes as a sine wave as shown in FIG.
[0042]
By counting the rotation signal and the eccentric signal with a counter through a rectangular circuit, the rotation angle and the eccentric amount of the encoder wheel 2 can be detected. In addition, when the A and B phase signals are output, the rotation and eccentric directions can be specified, and the resolution can be improved.
[0043]
As described above, the rotary encoder device 1 according to the present embodiment includes a rotation detection scale 10 formed of a diffraction grating formed on the rotating encoder wheel 2 so as to extend in the radial direction at a constant angle or a predetermined angle in the circumferential direction. An eccentricity detection scale 11 formed concentrically in the circumferential direction and made of a diffraction grating is formed, and the rotation detection scale 10 and the eccentricity detection scale 11 are irradiated with coherent light as detection light from the light irradiation means. Interference diffracted by the rotation detection scale 10 by the rotation detection light detector 13 and the eccentricity detection light detector 15 is irradiated with coherent light as detection light from the rotation detection light source unit 12 and the eccentricity detection light source unit 14. A fringe is detected and a rotation signal indicating the amount of rotation of the encoder wheel 2 is output, and an interference fringe diffracted by the eccentricity detection scale 11 is detected to detect the deviation of the encoder wheel 2. And it outputs the eccentric signal indicating the amount.
[0044]
Therefore, the eccentric amount of the encoder wheel 2 can be detected simultaneously with the rotation angle of the encoder wheel 2 without arranging a detector at a position opposite to the 180 ° as in the prior art, and the angle measurement result is corrected by the eccentric amount. Thus, the rotation angle can be measured at low cost and with high accuracy.
[0045]
FIG. 6 is a block diagram of a main part of the signal processing unit 21 of the rotary encoder device 20 to which the second embodiment of the rotary encoder device of the present invention is applied.
[0046]
The present embodiment is applied to a rotary encoder device similar to the rotary encoder device 1 of the first embodiment. In the description of the present embodiment, the first embodiment will be described. Components similar to those of the rotary encoder device 1 will be described using the same reference numerals used in the description of the first embodiment as necessary.
[0047]
In FIG. 6, the signal processing unit 21 of the rotary encoder device 20 includes a rotation signal processing unit 22 and an eccentric signal adjustment unit 23.
[0048]
The rotation signal processing unit 22 includes a pulse circuit (pulse unit) 24, and an analog rotation signal is input to the pulse circuit 24 from the rotation detection photodetector 13. The pulsing circuit 24 pulsates the analog rotation signal input from the rotation detection photodetector 13 and outputs it as a rotation pulse signal to a counter (not shown) at the subsequent stage of the signal processing unit 21. The signal is counted and converted into position data of the encoder wheel 2.
[0049]
The eccentric signal adjusting unit (eccentric signal adjusting means) 23 includes a pulsing circuit 25, and an analog eccentric signal is input to the pulsing circuit 25 from the eccentricity detecting photodetector 15.
[0050]
The pulsing circuit 25 converts the analog eccentric signal input from the eccentricity detection photodetector 15 into a pulse corresponding to the amount of eccentricity in one rotation of the encoder wheel 2, and is a subsequent circuit of the signal processing unit 21. For example, output to a counter.
[0051]
Next, the operation of the present embodiment will be described. As shown in FIG. 5, the rotation signal output from the rotation detection photodetector 13 is a number of sinusoidal analog signals corresponding to the number of rotation detection scales 10 of the encoder wheel 2. The rotary encoder device 20 pulsates the analog rotation signal by the pulse circuit 24 of the rotation signal processing unit 22 and outputs it as a rotation pulse signal to a counter (not shown) at the subsequent stage of the signal processing unit 21. The counter counts this rotation pulse signal and converts it into position data of the encoder wheel 2 to detect the moving position and angle of the encoder wheel 2.
[0052]
On the other hand, as shown in FIG. 5, the eccentric signal output from the eccentricity detecting photodetector 15 becomes a number of sinusoidal signals corresponding to the amount of eccentricity by one rotation of the encoder wheel 2, and in this signal state, The eccentric amount of the encoder wheel 2 cannot be measured.
[0053]
Therefore, the rotary encoder device 20 according to the present embodiment is provided with a pulsing circuit 25 in the eccentric signal adjusting unit 23 of the signal processing unit 21, and the pulsing circuit 25 receives an analog signal input from the eccentricity detection photodetector 15. Is converted into a pulse corresponding to the amount of eccentricity in one rotation of the encoder wheel 2 and output to a circuit, eg, a counter, at the subsequent stage of the signal processing unit 21.
[0054]
Therefore, as with the rotation signal, the amount of eccentricity can be accurately detected by the counter, and when the A and B phase pulses used internally by the encoder are generated, the amount of eccentricity can be detected by a general encoder counter. Can do.
[0055]
FIGS. 7 and 8 are block diagrams of the main part of the signal processing unit 31 of the rotary encoder device 30 to which the third embodiment of the rotary encoder device of the present invention is applied.
[0056]
The present embodiment is applied to the same rotary encoder device as the rotary encoder device 1 of the first embodiment and the rotary encoder device 20 of the second embodiment. In the description of the first embodiment, the same components as those of the rotary encoder device 1 of the first embodiment and the rotary encoder device 20 of the second embodiment are described as necessary. In addition, the reference numerals used in the description of the second embodiment are used as they are.
[0057]
In FIG. 7, the signal processing unit 31 of the rotary encoder device 30 includes a rotation signal processing unit 32 and an eccentric signal adjustment unit 33.
[0058]
The rotation signal processing unit 32 includes a pulsing circuit 24 and a delay circuit 34 similar to those in the second embodiment, and the eccentric signal adjustment unit 33 includes a pulsing circuit 25 similar to that in the second embodiment. A counter delay calculation circuit 35 is provided.
[0059]
The eccentric signal adjusting unit (eccentric signal adjusting means) 33 is a pulse circuit 25 for converting the analog eccentric signal input from the eccentricity detecting photodetector 15 into a pulse corresponding to the eccentric amount of one rotation of the encoder wheel 2. And the eccentric pulse signal is output to the counter delay calculation circuit 35. The counter delay calculation circuit 35 converts the rotation signal into a pulse width of the rotation pulse output from the pulsing circuit 24 for pulsing the rotation signal. To the delay circuit 34 of the unit 32.
[0060]
The rotation signal processing unit 32 pulsates the analog rotation signal input from the rotation detection photodetector 13 in the pulsing circuit 24 and outputs it to the delay circuit 34 as a rotation pulse signal. The delay circuit 34 Based on the eccentricity data converted into the pulse width of the rotation pulse output from the pulse conversion circuit 24 by the counter delay calculation circuit 35, the rotation pulse signal input from the pulse conversion circuit 24 is adjusted to a pulse width corresponding to the amount of eccentricity. And output.
[0061]
The delay circuit 34 calculates a rotation detection error from the eccentricity data indicating the eccentricity amount of the encoder wheel 2 input from the counter delay calculation circuit 35, calculates the calculated error as a time corresponding to the rotation speed, A circuit for delaying the rotation pulse output from the pulse circuit 24 or a CPU (Central Processing Unit) incorporating software is configured. The delay circuit 34 and the counter delay calculation circuit 35 function as signal adjusting means.
[0062]
Then, the rotation signal emitted from the light source 16 of the rotation detection unit 3 and transmitted and diffracted through the rotation detection scale 10 of the encoder wheel 2 and detected by the rotation detection photodetector 13 is converted into a pulse circuit of the rotation signal processing unit 22. At 24, the pulse is converted into a rotation pulse signal Sp indicated by a broken line in FIG.
[0063]
At this time, if the encoder wheel 2 is eccentric, the angle measurement error is δθ as the detection angle of the one-rotation detection scale 10 of the encoder wheel 2 when the amount of eccentricity is δ and the scale angle period is θ. .
[0064]
However, as described above, the rotation signal processing unit 32 is provided with the delay circuit 34. The delay circuit 34 detects an angle detection error due to eccentricity, calculates the angle detection error as a rotation angle pulse width, and outputs the rotation pulse signal. When a delay is applied, as shown by the solid line in FIG. 8, the output rotation pulse signal Spg after adjustment has a waveform obtained by adding an eccentricity error to the output edge.
[0065]
Actually, it is difficult for an electric circuit to apply a delay to minus, but the delay is set to “0” at a position where the error due to the eccentricity of the encoder wheel 2 is minimum, the error due to the eccentricity increases, and the pulse period is increased. Can be accommodated by setting so as to be longer. Further, in order to delay the rotation signal, the rotation speed, that is, the rotation pulse signal needs to be output first. In addition to the continuous rotation, the delay circuit 34 becomes an error factor. By providing a function for determining whether or not there is, it is possible to cope with it and to perform highly accurate measurement.
[0066]
Therefore, it is possible to perform counting and angle calculation with a commonly used encoder circuit using a rotation signal that has already been corrected for eccentricity, making it easier to use an inexpensive and high-accuracy rotation signal for use. Can be improved.
[0067]
FIG. 9 and FIG. 10 are main part block configuration diagrams of the signal processing unit 41 of the rotary encoder device 40 to which the fourth embodiment of the rotary encoder device of the present invention is applied.
[0068]
The present embodiment is applied to the same rotary encoder device as the rotary encoder device 1 of the first embodiment and the rotary encoder device 20 of the second embodiment. In the description of the first embodiment, the same components as those of the rotary encoder device 1 of the first embodiment and the rotary encoder device 20 of the second embodiment are described as necessary. In addition, the reference numerals used in the description of the second embodiment are used as they are.
[0069]
In FIG. 9, the signal processing unit 41 of the rotary encoder device 40 includes a rotation signal processing unit 42 and an eccentric signal adjustment unit 43.
[0070]
The rotation signal processing unit 42 includes a pulsing circuit 24, a pulse width changing circuit 44, and a pulse synthesizing circuit 45 similar to those in the second embodiment, and the eccentric signal adjusting unit 43 includes the second embodiment. A pulse forming circuit 25 and a pulse width changing circuit 46 similar to those of the embodiment are provided.
[0071]
The pulsating circuit (eccentric signal adjusting means) 25 of the eccentric signal adjusting unit 43 converts the analog eccentric signal (see FIG. 5) input from the eccentricity detecting photodetector 15 into the amount of eccentricity in one rotation of the encoder wheel 2. 10 is output to the pulse width changing circuit 46. The eccentric pulse signal shown in FIG. A reference clock is input to the pulse width changing circuit (rotated eccentric pulse generating means) 46, and the pulse width changing circuit 46 performs a flip-flop operation at the signal edge of the rotating pulse, so that the pulse generating circuit 25 When the input eccentric pulse signal is equivalent to one pulse of the rotation pulse output from the pulsing circuit 24 for pulsing the rotation signal, a narrow-width eccentric pulse (rotated eccentric pulse shown in FIG. ) And output to the pulse synthesis circuit 45 of the rotation signal processing unit 42.
[0072]
The rotation signal processing unit 42 pulsates an analog rotation signal (see FIG. 5) input from the rotation detection photodetector 13 with a pulse circuit (pulse unit) 24, and outputs a pulse width as a rotation pulse signal. Output to the change circuit 44. A reference clock is input to the pulse width change circuit (rotation pulse width conversion means) 44, and the pulse width change circuit 44 performs a flip-flop operation at the signal edge of the rotation signal, so that the duty ratio of the rotation pulse signal is increased. Is reduced (high-level width is shortened), and a narrow rotation pulse shown in FIG. 10B is output to the pulse synthesis circuit 45. The pulse synthesizing circuit (pulse adding means) 45 adds and synthesizes the narrow eccentric pulse inputted from the pulse width changing circuit 46 and the narrow rotation pulse inputted from the pulse width changing circuit 44, and FIG. For example, a correction rotation pulse (eccentric adjustment rotation signal) corresponding to the eccentricity shown in FIG.
[0073]
Since this output pulse includes a pulse whose eccentricity is corrected in addition to the rotation signal, the rotation angle with a small eccentricity error can be detected by counting this output pulse with a normal counter. .
[0074]
As described above, the rotary encoder device 40 of the present embodiment includes the pulsing circuit 24 that converts the rotation signal output from the rotation detection photodetector 13 into the rotation pulse signal, and the rotation pulse signal output from the pulsing circuit 24. Is converted into a narrow rotation pulse signal having a predetermined short pulse width, and a pulsing circuit 25 for converting the eccentric signal output from the eccentricity detection photodetector 15 into an eccentric pulse signal corresponding to the eccentricity amount. The eccentric pulse signal output from the pulsing circuit 25 is converted into a rotated eccentric pulse signal every time the eccentric amount indicated by the eccentric pulse signal corresponds to one pulse of the narrow rotation pulse signal output from the pulse width changing circuit 44. The pulse width changing circuit 46, the narrow rotation pulse signal output from the pulse width changing circuit 44, and the rotated eccentric pulse signal generated by the pulse width changing circuit 46 are added. A pulse synthesizing circuit 45 and output as an eccentric adjusting rotation signal Te is a provided.
[0075]
Therefore, it is possible to perform counting and angle calculation with a commonly used encoder circuit using a rotation signal that has already been corrected for eccentricity, making it easier to use an inexpensive and high-accuracy rotation signal for use. Can be improved.
[0076]
FIG. 11 is a schematic configuration diagram of the light source unit 51 of the rotary encoder device 50 to which the fifth embodiment of the rotary encoder device of the present invention is applied.
[0077]
The present embodiment is applied to a rotary encoder device similar to the rotary encoder device 1 of the first embodiment. In the description of the present embodiment, the first embodiment will be described. Components similar to those of the rotary encoder device 1 will be described using the same reference numerals used in the description of the first embodiment as necessary.
[0078]
In FIG. 11, the light source unit 51 of the rotary encoder device 50 includes a light source 52, a lens 53, and two light beam splitting elements 54 and 55.
[0079]
The two light beam splitting elements 54 and 55 are arranged side by side on the optical axis of the light beam emitted from the light source 52, and each uses a light beam splitter. When a light beam splitter is used as the light beam splitting elements 54 and 55, if a deflected light beam splitter is used as the light beam splitter, the split light quantity can be changed by adjusting the incident deflection angle.
[0080]
In the rotary encoder device 50 of the present embodiment, the light source unit 52 is shared for rotation detection and eccentricity detection.
[0081]
That is, the light beam emitted from the light source 52 is converted into parallel light by the lens 52 and first enters the light beam splitting element 54 for rotation detection. The light beam splitting element 54 shows a part of the incident light. Not reflected to the rotation detection scale 10 of the encoder wheel 2, and part of it is transmitted to the light beam splitting element 55 for detecting eccentricity.
[0082]
The light beam splitting element 55 for detecting eccentricity reflects all the beams transmitted through the light beam splitting element 54 to the eccentricity detection scale 11 of the encoder wheel 2.
[0083]
Therefore, by dividing the light of the light source by the light beam splitting element and using it for rotation detection and eccentricity detection, a high-cost light source can be omitted, and the cost can be reduced.
[0084]
In place of the two light beam splitting elements 54 and 55, a diffraction grating 56 may be used as shown in FIG.
[0085]
In this case, the irradiation light emitted from the light source 52 and converted into parallel light by the lens 53 is divided into two by the diffraction grating 56, and one of them is irradiated to the rotation detection scale 10 of the encoder wheel 2 as irradiation light for rotation detection. The other is made to irradiate the eccentricity detection scale 11 of the encoder wheel 2 as the irradiation light for detecting the eccentricity.
[0086]
As described above, in the rotary encoder device 50 according to the present embodiment, the light source unit 51 is provided with one light source 52 and the light from the light source 52 is divided into rotation detection detection light and eccentricity detection detection light. The division element 54 is provided, the rotation detection detection light is incident on the rotation detection scale 10, and the eccentricity detection detection light is incident on the eccentricity detection scale 11.
[0087]
Therefore, an expensive light source can be reduced, and measurement can be performed more inexpensively and with high accuracy.
[0088]
FIG. 13 is a diagram showing a sixth embodiment of the rotary encoder device of the present invention, and FIG. 13 is an encoder wheel of the rotary encoder device 60 to which the sixth embodiment of the rotary encoder device of the present invention is applied. It is a principal part expansion perspective view of 61. FIG.
[0089]
The present embodiment is applied to a rotary encoder device similar to the rotary encoder device 1 of the first embodiment. In the description of the present embodiment, the first embodiment will be described. Components similar to those of the rotary encoder device 1 will be described using the same reference numerals used in the description of the first embodiment as necessary.
[0090]
In FIG. 13, the encoder wheel 61 has a light splitting diffraction grating 62 formed as a light splitting element on the incident side (upper side in FIG. 13) of the detection light (incident light), and the detection light exit side (FIG. 13). A rotation detection scale 63 and an eccentricity detection scale 64 are formed on the lower side.
[0091]
The rotation detection scale 63 is for detecting the rotation angle of the encoder wheel 61, and is a diffraction grating that extends in the radial direction and is thin, and is formed as a scale at a constant angle or a predetermined angle.
[0092]
The eccentricity detection scale 64 is for detecting the eccentricity of the encoder wheel 61 and is a diffraction grating formed concentrically in the circumferential direction of the encoder wheel 2 that is the rotation direction of the rotation detection scale 10.
[0093]
Although not shown, the rotary encoder device 60 of the present embodiment has one light source in its light source section.
[0094]
Therefore, in the rotary encoder device 60 of the present embodiment, the detection light emitted from one light source is divided into two by the light division diffraction grating 62 formed on the incident side of the encoder wheel 61, and one is used as the rotation detection light. The light is incident on the rotation detection scale 63 and the other light is incident on the eccentricity detection scale 64 as the eccentricity detection light.
[0095]
Therefore, the rotation detection light detector 13 detects the interference fringes of the rotation detection light that has been diffracted through the rotation detection scale 63, so that the rotation angle of the encoder wheel 61 can be detected. The eccentricity of the encoder wheel 61 can be detected by detecting the interference fringes of the eccentricity detection light diffracted by passing through the eccentricity detection photodetector 15.
[0096]
In the present embodiment, the light splitting element is not limited to the light splitting diffraction grating 62, but may be a light splitting prism 65 as shown in FIG.
[0097]
In this case, the light splitting prism 65 is formed on the detection light (incident light) incident side of the encoder wheel 61 (upper side in FIG. 14).
[0098]
As in the case of the light splitting diffraction grating 62, the light splitting prism 65 splits the detection light emitted from one light source into two by the light splitting diffraction grating 62 formed on the incident side of the encoder wheel 61, and one of them. The light is incident on the rotation detection scale 63 as rotation detection light, and the other is incident on the eccentricity detection scale 64 as eccentricity detection light.
[0099]
As described above, the rotary encoder device 60 according to the present embodiment is provided with the light splitting diffraction grating 62 or the light splitting prism 65 as the light splitting element in the encoder wheel 61, and detects rotation using one of the split lights as the rotation detection light. The light is incident on the scale 63 and the other light is incident on the eccentricity detection scale 64 as the eccentricity detection light.
[0100]
Therefore, an expensive light source can be reduced, and a light splitting element can be formed on the encoder wheel 61 to reduce the size of the apparatus, thereby making it possible to perform measurement at a lower cost and with higher accuracy.
[0101]
FIG. 15 is an enlarged plan view of a main part of an encoder wheel 71 of a rotary encoder device 70 to which a seventh embodiment of the rotary encoder device of the present invention is applied.
[0102]
The present embodiment is applied to a rotary encoder device similar to the rotary encoder device 1 of the first embodiment. In the description of the present embodiment, the first embodiment will be described. Components similar to those of the rotary encoder device 1 will be described using the same reference numerals used in the description of the first embodiment as necessary.
[0103]
In FIG. 15, the encoder wheel 71 is formed in a disk shape like the encoder wheel 2 of the rotary encoder device 1 of the first embodiment, and the encoder wheel 71 includes a rotation detection scale 10 made of a diffraction grating, An eccentricity detection scale 72 made of a diffraction grating formed concentrically in the circumferential direction of the encoder wheel 71 is formed.
[0104]
An origin detection mark 73 is formed on the eccentricity detection scale 72, and in this embodiment, a gap (a portion without a diffraction grating) serving as a light shielding portion is formed on a part of the eccentricity detection scale 72 made of a diffraction grating. The origin detection mark 73 is formed.
[0105]
As described above, when the origin detection mark 73 that is a light shielding portion is formed on a part of the eccentricity detection scale 72 formed of the diffraction grating, the light is emitted from the light source 16 of the eccentricity detection light source unit 14 and the encoder wheel 71 The detection light condensed in front is blocked by the origin detection mark 73, and the amount of light received by the eccentricity detection photodetector 15 becomes “0” at the origin detection mark 73.
[0106]
If the portion where the amount of received light is “0” is used as the origin, the origin of the encoder can be detected by the same optical system as that for detecting the eccentricity.
[0107]
Since the change in the amount of eccentricity is very slow compared to the rotation signal, even if there is no data in part of the eccentricity data, it is not likely to cause an error, and the origin detection mark 73 is not only at one place but at a plurality of places. You may create it. In addition, by creating a code indicating the origin position (for example, several consecutive parts without slits), the origin can be adjusted not only once per rotation of the encoder wheel 71, and the origin return can be performed. Can be easily performed to improve convenience.
[0108]
The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0109]
For example, in each of the above embodiments, the eccentricity detection signal is used to correct the rotation signal. However, not only the correction of the rotation signal but also the error signal of the detection unit mounting error and encoder wheel mounting error It may be used as
[0110]
In this case, for example, the eccentricity data may be analog data as it is, or an error signal may be output with a threshold value. With this error signal, the user can confirm the attachment position of the detection unit or the encoder wheel. Encourage confirmation of mounting eccentricity outside the allowable range.
[0111]
【The invention's effect】
According to the rotary encoder device of the first aspect of the present invention, the rotation encoder scale formed on the rotating encoder wheel and extending in the radial direction at a constant angle or a predetermined angle in the circumferential direction is formed of a diffraction grating; An eccentricity detection scale formed concentrically in the direction and made of a diffraction grating is formed, and the rotation detection scale and the eccentricity detection scale are irradiated with coherent light as detection light from the light irradiation means, and the detection means irradiates from the light irradiation means. In addition to detecting the interference fringes diffracted by the rotation detection scale and outputting a rotation signal indicating the amount of rotation of the encoder wheel, the interference fringes diffracted by the eccentricity detection scale are detected and an eccentric signal indicating the amount of eccentricity of the encoder wheel is output. Since the output is performed at the same time as the rotation angle of the encoder wheel, the detector is not disposed at a position opposed to 180 ° as in the prior art. Can detect the eccentricity of Dahoiru, by correcting the angle measurement results in eccentricity, it is possible to perform measurement of the rotation angle at low cost and with high accuracy.
[0112]
According to the rotary encoder device of the second aspect of the present invention, the pulsing unit that converts the rotation signal output from the detection unit into the rotation pulse signal, and the eccentric signal output from the detection unit into the eccentric pulse signal corresponding to the eccentric amount. The eccentric signal adjusting means for converting, and the eccentric pulse signal output from the eccentric signal adjusting means, converting the eccentric amount indicated by the eccentric pulse signal into the pulse width of the eccentric amount relative to the pulse width of the rotation pulse signal output from the pulsing means, A rotation signal adjusting means for adjusting the pulse width of the rotation pulse signal output from the pulsing means with the pulse width, and an encoder circuit that is generally used using a rotation signal that has already been corrected for eccentricity Can perform counting and angle calculation, making it easier to use inexpensive and highly accurate rotation signals and improving usability
[0113]
According to the rotary encoder device of the invention described in claim 3, the pulsing means for converting the rotation signal output from the detection means into the rotation pulse signal, and the rotation pulse signal output from the pulsing means are reduced to a predetermined short pulse width. Rotation pulse width conversion means for converting into a width rotation pulse signal, eccentric signal adjustment means for converting an eccentric signal output from the detection means into an eccentric pulse signal corresponding to the eccentric amount, and an eccentric pulse signal output from the eccentric signal adjustment means Rotating eccentric pulse generating means for converting to an eccentric eccentric pulse signal each time the eccentric amount indicated by the eccentric pulse signal corresponds to one pulse of the narrow width rotating pulse signal output from the rotating pulse width converting means, and rotating pulse width conversion The narrow rotation pulse signal output by the means and the rotation eccentric pulse signal generated by the rotation eccentric pulse generation means are added and output as an eccentricity adjustment rotation signal. And a pulse addition means, so that it is possible to perform counting and angle calculation with a commonly used encoder circuit using a rotation signal that has already been corrected for eccentricity, and an inexpensive and highly accurate rotation signal can be obtained. Usability can be improved by making it easier to use.
[0114]
According to the rotary encoder device of the invention described in claim 4, the light irradiating means is provided with one light source, and the light splitting means for splitting the light from the light source into the detection light for rotation detection and the detection light for eccentricity detection is provided. Since the detection light for rotation detection is incident on the rotation detection scale and the detection light for eccentricity detection is incident on the eccentricity detection scale, the expensive light source can be reduced, and the measurement is more inexpensive and highly accurate. It can be performed.
[0115]
According to the rotary encoder device of the fifth aspect, the error discriminating means for discriminating an attachment error of the detecting means or the encoder wheel based on the eccentric signal outputted from the detecting means and outputting an error signal indicating the error discriminating result. Since it is provided, it is possible to easily detect an attachment error of the detecting means or the encoder wheel, and it is possible to improve the workability of the attachment work and further improve the usability.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a rotary encoder device to which a first embodiment of a rotary encoder device of the present invention is applied.
FIG. 2 is an enlarged front sectional view of the scale portion when the scale of FIG. 1 is a relief type diffraction grating.
FIG. 3 is a front enlarged front view of a scale portion when the scale of FIG. 1 is a volume type diffraction grating.
4 is an enlarged front view of the rotation and eccentricity detection unit of FIG. 1;
5 is a diagram illustrating a relationship between a rotation signal and an eccentric signal of the rotary encoder device of FIG. 1 in one rotation of an encoder wheel.
FIG. 6 is a block diagram of a main part of a signal processing unit of a rotary encoder device to which a second embodiment of the rotary encoder device of the present invention is applied.
FIG. 7 is a block diagram of a main part of a signal processing unit of a rotary encoder device to which a third embodiment of the rotary encoder device of the present invention is applied.
8 is a view showing a rotation pulse in which the pulse width of the rotation pulse is adjusted to a pulse width corresponding to the amount of eccentricity based on the eccentricity data in the signal processing unit of FIG. 7;
FIG. 9 is a block diagram of a main part of a signal processing unit of a rotary encoder device to which a fourth embodiment of the rotary encoder device of the present invention is applied.
10 is a waveform diagram showing signal processing in the signal processing unit of FIG. 9;
FIG. 11 is a schematic configuration diagram of a light source unit of a rotary encoder device to which a fifth embodiment of a rotary encoder device of the present invention is applied.
12 is a schematic configuration diagram of a light source unit of a rotary encoder device using a diffraction element instead of the light beam splitting element of FIG.
FIG. 13 is a perspective view of an essential part of an encoder wheel in which a light splitting diffraction element is formed on the surface of a rotary encoder device to which a sixth embodiment of the rotary encoder device of the present invention is applied.
14 is a perspective view of a main part of an encoder wheel using a light splitting prism instead of the light splitting diffraction element of the encoder wheel of FIG. 13;
FIG. 15 is an enlarged plan view of a main part of an encoder wheel of a rotary encoder device to which a rotary encoder device according to a seventh embodiment of the invention is applied.
[Explanation of symbols]
1 Rotary encoder device
2 Encoder wheel
3 Rotation detector
4 Eccentricity detector
10 Rotation detection scale
11 Eccentricity detection scale
12 Light source for rotation detection
13 Photodetector for rotation detection
14 Light source for detecting eccentricity
15 Photodetector for detecting eccentricity
16 Light source
17 Lens
18 mask
20 Rotary encoder device
21 Signal processor
22 Rotation signal processor
23 Eccentric signal adjuster
24 Pulse circuit
25 Pulse circuit
30 Rotary encoder device
31 Signal processor
32 Rotation signal processor
33 Eccentric signal adjuster
34 Delay circuit
35 Counter delay calculation circuit
40 Rotary encoder device
41 Signal processor
42 Rotation signal processor
43 Eccentric signal adjuster
44 Pulse width change circuit
45 Pulse synthesis circuit
46 Pulse width change circuit
50 Rotary encoder device
51 Light source
52 Light source
53 lenses
54, 55 Light beam splitter
56 diffraction grating
60 Rotary encoder device
61 Encoder wheel
62 Optical Splitting Diffraction Element
63 Rotation detection scale
64 Eccentricity detection scale
65 Light splitting prism
70 Rotary encoder device
71 Encoder wheel
72 Eccentricity detection scale
73 Origin detection mark

Claims (4)

Circumferentially formed to extend in the radial direction at a constant angle or predetermined angle detecting scale composed of the diffraction grating, and the rotation eccentricity detecting scale composed of the diffraction grating is formed concentrically in the circumferential direction is formed An encoder wheel to
A light irradiation means for irradiating the rotation detection scale and the eccentricity detection scale with coherent light as detection light;
The interference fringe irradiated from the light irradiation means and diffracted by the rotation detection scale is detected and a rotation signal indicating the rotation amount of the encoder wheel is output, and the interference fringe diffracted by the eccentricity detection scale is detected and the interference fringe is detected. Detecting means for outputting an eccentric signal indicating the eccentric amount of the encoder wheel;
Pulsing means for converting the rotation signal output from the detection means into a rotation pulse signal;
An eccentric signal adjusting means for converting an eccentric signal output from the detecting means into an eccentric pulse signal corresponding to an eccentric amount;
The eccentric pulse signal output from the eccentric signal adjusting means is converted into the pulse width of the eccentric amount with respect to the pulse width of the rotation pulse signal output from the pulsing means by converting the eccentric amount indicated by the eccentric pulse signal into the pulse with the pulse width. Rotation signal adjusting means for adjusting the pulse width of the rotation pulse signal output from the converting means;
A rotary encoder device comprising: A rotation detection scale formed of a diffraction grating formed to extend in the radial direction at a constant angle or a predetermined angle in the circumferential direction, and an eccentric detection scale formed of a diffraction grating concentrically formed in the circumferential direction are formed and rotated An encoder wheel,
A light irradiation means for irradiating the rotation detection scale and the eccentricity detection scale with coherent light as detection light;
The interference fringe irradiated from the light irradiation means and diffracted by the rotation detection scale is detected and a rotation signal indicating the rotation amount of the encoder wheel is output, and the interference fringe diffracted by the eccentricity detection scale is detected and the interference fringe is detected. Detecting means for outputting an eccentric signal indicating the eccentric amount of the encoder wheel;
Pulsing means for converting the rotation signal output from the detection means into a rotation pulse signal;
Rotation pulse width conversion means for converting the rotation pulse signal output from the pulsing means into a narrow rotation pulse signal having a predetermined short pulse width;
An eccentric signal adjusting means for converting an eccentric signal output from the detecting means into an eccentric pulse signal corresponding to an eccentric amount;
The eccentric pulse signal output from the eccentric signal adjusting means is converted into a rotated eccentric pulse signal every time the eccentric amount indicated by the eccentric pulse signal corresponds to one pulse of the narrow rotational pulse signal output from the rotational pulse width converting means. Rotating eccentric pulse generating means,
A pulse addition means for adding the narrow rotation pulse signal output from the rotation pulse width conversion means and the rotation eccentric pulse signal generated by the rotation eccentric pulse generation means to output as an eccentricity adjustment rotation signal;
A rotary encoder device comprising: In the rotary encoder device, the light irradiation means includes one light source, and includes light splitting means for splitting light from the light source into detection light for rotation detection and detection light for eccentricity detection, and the detection for rotation detection. 3. The rotary encoder device according to claim 1, wherein light is incident on the rotation detection scale, and the eccentricity detection detection light is incident on the eccentricity detection scale. The rotary encoder device includes an error determination unit that determines an attachment error of the detection unit or the encoder wheel based on an eccentric signal output from the detection unit and outputs an error signal indicating an error determination result. The rotary encoder device according to any one of claims 1 to 3, characterized in that:

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