Encoder with identification information detection function

Abstract

To provide an encoder having an identification information detection function.SOLUTION: A scale 6 of an encoder 4 comprises: an ID pattern 61 in which a plurality of magnetization parts are arrayed; a periodic pattern in which a unit pattern 62 consisting of an S pole and an N pole is repeatedly arrayed in an X direction at a first pitch P1; and an absolute position pattern 63 constituting of a magnetization part. A sensor part 5 of the encoder 4 comprises: a row of ID sensors 10 facing the ID pattern 61; an interpolation position sensor group 20 that outputs for one cycle a sin signal and a cos signal in which a phase is displaced by π / 2 every time the unit pattern 62 passes once; and a row of absolute position sensors 30 arrayed in the X direction at the first pitch P1. A data processing part 7 of the encoder 4 calculates absolute position information by using position information of low resolution obtained from signals of the absolute position sensors 30, and position information of high resolution obtained from the sin signal and the cos signal. A range of the ID sensors 10 detecting the ID pattern 61 is determined from the position information of low resolution in order to calculate identification information.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an encoder with an identification information detection function. [Background technology]

[0002] Patent Document 1 describes a conveying device that includes a conveying guide, a conveying unit that moves on the conveying guide, and a linear motor for moving the conveying unit, and that also includes a position detection device that detects the position and identification information (ID) of the conveying unit. A scale on which absolute data is recorded is disposed in the conveying unit. A detection unit that reads the absolute data from the scale is disposed in the conveying guide. The position detection device extracts position data of the conveying unit and identification information (scale ID) of the conveying unit from the read absolute data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7258515 Summary of the Invention [Problem to be solved by the invention]

[0004] In the position detection device of Patent Document 1, multiple five-digit numbers are attached to the scale of each transport unit as multiple absolute data aligned in the transport direction. Each absolute data includes position data and a scale ID. The multiple absolute data aligned in the transport direction have different position data portions but the same scale ID. The position detection device determines the scale ID from the read absolute data using a table that associates scale IDs with absolute data. Then, the position data portion is extracted from the read absolute data. This allows the position data and scale ID to be detected.

[0005] The position detection method of Patent Document 1 appears to require an MR element, and the load of arithmetic processing of the read data is large, requiring a large storage area, resulting in high costs. Furthermore, to improve the resolution of the position data, the scale and detection unit must be configured to be able to read absolute data of small sizes with high accuracy. Therefore, the gap between the scale and detection unit and the dimensions of each part must be controlled with high precision. This makes manufacturing difficult and expensive.

[0006] In view of the above problems, the present invention proposes an inexpensive encoder with an identification information detection function that can detect identification information and absolute position information, while having high resolution. [Means for solving the problem]

[0007] In order to solve the above problems, a first aspect of the present invention provides a data processing unit that includes a sensor unit, a scale that moves relatively with respect to the sensor unit, and a data processing unit that calculates absolute position information and identification information of the scale using a signal from the sensor unit, wherein the scale includes a first track on which an ID pattern is arranged in a moving direction of the scale relative to the sensor unit, a second track on which a periodic pattern is arranged in which unit patterns each consisting of a pair of the detectable elements that are different from each other are repeatedly arranged at a first pitch in the moving direction, and a third track on which an absolute position pattern made up of the detectable elements is arranged, and the sensor unit includes a first sensor unit that faces the first track and has a row of ID sensors that are arranged in the moving direction, a second sensor unit that faces the second track and has an interpolation position sensor group that outputs a sine signal and a cosine signal that are shifted in phase by π / 2 for one period each time the unit pattern passes through, and and a third sensor unit facing the track and including a row of absolute position sensors lined up in the movement direction at the first pitch, wherein the data processing unit calculates the absolute position information using low-resolution position information obtained from signals of the absolute position sensors that detect the absolute position pattern and high-resolution position information obtained from the sine signal and the cosine signal, determines a range of the ID sensors in the row that detects the ID pattern using the low-resolution position information, and calculates the identification information using signals of the ID sensors in the determined range.

[0008] In order to solve the above problem, a second aspect of the present invention provides a data processing unit that includes a sensor unit, a scale that moves relatively with respect to the sensor unit, and a data processing unit that calculates absolute position information and identification information of the scale using a signal from the sensor unit, wherein the scale includes: a first track on which an ID pattern is arranged in which detectable elements are arranged in a moving direction of the scale relative to the sensor unit; a second track on which a periodic pattern is arranged in which unit patterns made of different pairs of the detectable elements are repeatedly arranged at a first pitch in the moving direction; and a third track on which an absolute position pattern is arranged made of the detectable elements, the absolute position pattern being longer than the first pitch and shorter than twice the first pitch; and wherein the sensor unit includes an ID sensor that faces the first track and is arranged in the moving direction. a second sensor unit facing the second track and having a group of interpolation position sensors that output one period of sine signals and cosine signals that are shifted in phase by π / 2 each time the unit pattern passes once; and a third sensor unit facing the third track and having a row of absolute position sensors that are lined up in the movement direction at the first pitch, wherein the data processing unit determines which of the signals of two adjacent absolute position sensors that detected the absolute position pattern to use based on the high-resolution position information when calculating the absolute position information using low-resolution position information determined from the signals of the absolute position sensors that detected the absolute position pattern and high-resolution position information determined from the sine signals and cosine signals. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram of a transport system. [Figure 2] FIG. 2 is an explanatory diagram of the sensor unit and the scale. [Figure 3] FIG. 3 is an explanatory diagram showing a situation in which a plurality of scales move over a plurality of sensor units. [Figure 4] FIG. 4 is an explanatory diagram of a process for calculating high-resolution position information from signals from the interpolation position sensor group. [Figure 5] FIG. 5 is an explanatory diagram of the process of calculating absolute position information. [Figure 6] FIG. 6 is a flowchart of a process for calculating absolute position information. [Figure 7] FIG. 7 is an explanatory diagram of the process of calculating the identification information. [Figure 8] FIG. 8 is a flowchart of the process for calculating the identification information. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of an encoder with an identification information detection function according to the present invention will be described.

[0011] In this specification, the configuration of an encoder with identification information detection function will be described, including the sensor placed in the sensor section, which is its main part, and the specific configuration of the detection pattern placed on the track, but descriptions of other parts (such as the outer case) will be omitted.

[0012] (Overall structure) FIG. 1 is an explanatory diagram of a conveyance system 1. The conveyance system 1 shown in FIG. 1 includes a rail 2 and a mover 3 that travels along the rail 2. The mover 3 is driven by, for example, a linear motor (not shown) that includes a coil arranged on the rail 2 and a magnet arranged on the mover 3. The conveyance system 1 moves a plurality of movers 3 on the rail 2, thereby generating a movable The transport system 1 moves an object carried on the mover 3. Identification information is attached to the mover 3. The transport system 1 includes an encoder 4 (hereinafter referred to as "encoder 4") with an identification information detection function that detects the identification information attached to each of the multiple movers 3 and the absolute position of the mover 3.

[0013] The encoder 4 includes a sensor unit 5 arranged on the rail 2, a scale 6 arranged on the mover 3, and a data processing unit 7. The scale 6 is provided with a detectable element that is detected by the sensor unit 5. The data processing unit 7 calculates absolute position information and identification information of the scale 6 using a signal output from the sensor unit 5. In this embodiment, the detectable element is a magnetized portion magnetized with an S pole or N pole. The sensor unit 5 detects the magnetic field of the magnetized portion using a Hall element.

[0014] The conveying system 1 conveys one or more objects by controlling the positions of one or more movers 3 based on the identification information and absolute position information detected by the encoder 4. In the example shown in FIG. 1, the sensor section 5 includes multiple sensor units 8 arranged in a row along the rail 2. The sensor units 8 are arranged to cover the range in which the mover 3 moves. A scale 6 provided on the mover 3 faces the sensor units 8. In this specification, the movement direction of the mover 3 is defined as the X direction, and the direction perpendicular to the X direction is defined as the Y direction. The Y direction is the width direction of the sensor unit 8. One side of the X direction is defined as the X1 direction, and the other side of the X direction is defined as the X2 direction. One side of the Y direction is defined as the Y1 direction, and the other side of the Y direction is defined as the Y2 direction.

[0015] FIG. 2 is an explanatory diagram of the sensor unit 8 and the scale 6. The sensor unit 8 has an elongated shape with a length in the X direction longer than the scale 6. FIG. 3 is an explanatory diagram showing a situation in which the mover 3 moves over the sensor unit 8. As shown in FIG. 3, in the conveyance system 1, multiple movers 3 may move over one sensor unit 8. Furthermore, the mover 3 moves across multiple sensor units 8. In FIG. 3, two sensor units 8M-1 and 8M are lined up, and one of the movers 3 is in a position that straddles the sensor units 8M-1 and 8M.

[0016] (scale) As shown in FIG. 2, the scale 6 includes a first track 6A, a second track 6B, and a third track 6C. The first track 6A, the second track 6B, and the third track 6C are provided on a plate 60 whose longitudinal direction is in the X direction and whose lateral direction is in the Y direction. The first track 6A is provided at an end of the plate 60 in the Y1 direction. The second track 6B is provided in the center of the plate 60 in the Y1 direction. The third track 6C is provided at an end of the plate 60 in the Y2 direction. However, the arrangement of these three tracks is not limited to this arrangement.

[0017] The first track 6A, the second track 6B, and the third track 6C each comprise one or more detectable elements. As described above, the detectable elements comprise a magnetized portion magnetized to an S pole and a magnetized portion magnetized to an N pole. Each magnetized portion is, for example, a permanent magnet. In the drawings of this specification, a magnetized portion magnetized to an S pole is indicated by the symbol S, and a magnetized portion magnetized to an N pole is indicated by the symbol N. In this embodiment, the detectable elements (magnetized portions) provided on each track have different lengths in the X direction.

[0018] An ID pattern 61 is arranged on the first track 6A, in which a plurality of ID elements, each of which is made up of an identically sized element to be detected, are arranged in the X direction. In this embodiment, an example of the ID pattern 61 is a pattern in which eight ID elements ID00, ID01, ID02, ..., ID07 are arranged in a row. The ID elements ID00, ID01, ID02, ..., ID07 are arranged at a first pitch P1. The length of each ID element in the X direction is P1.

[0019] The second track 6B has a periodic pattern in which unit patterns 62, each of which has a pair of different elements to be detected aligned in the X direction, are repeatedly aligned in the X direction. Each unit pattern 62 is a magnetization pattern in which a pair of south pole and north pole is aligned in the X direction. The arrangement pitch of the unit patterns 62 is the same as the first pitch P1. Therefore, in the second track 6B, the length in the X direction of the south pole and north pole that make up the unit pattern 62 is half the first pitch P1.

[0020] The third track 6C has an absolute position pattern 63 consisting of one detectable element. The absolute position pattern 63 is a magnetized portion of a single polarity. The length of the absolute position pattern 63 in the X direction is longer than the first pitch P1 but shorter than twice the first pitch P1.

[0021] As shown in FIG. 2, in this embodiment, the first pitch P1 is 6 mm. Therefore, the length in the X direction of the ID pattern 61, which is made up of eight ID elements, is 48 mm. The length L1 in the X direction of the plate 60 is an integer multiple of the first pitch P1 and is longer than the ID pattern 61. In this embodiment, L1 = 60 mm. The ID pattern 61 is disposed at the center of the plate 60 in the X direction.

[0022] The second track 6B has a periodic pattern in which nine unit patterns 62 are repeated. The length of the periodic pattern in the X direction is 54 mm and it is located at the center of the plate 60 in the X direction. One magnetization pattern 64 is located on each of the X1 and X2 sides of the periodic pattern. The magnetization pattern 64 has the same size as the adjacent magnetized portions and has a different polarity from the adjacent magnetized portions. In the second track 6B, the magnetization pattern 64 is located at the end of the plate 60, so there is only one adjacent magnetized portion in the X direction. Therefore, the magnetic flux from the magnetized portion of the unit pattern 62 with magnetization portions located on both sides is different from the magnetic flux from the magnetization pattern 64. Therefore, although a total of 20 magnetized portions are arranged on the second track 6B, the two magnetized portions at both ends do not constitute a unit pattern 62, and the number of unit patterns 62 is nine periods. In the ID pattern 61, the positions of the boundaries between adjacent ID elements all coincide with the positions of the boundaries between the south pole and the north pole in the second track 6B.

[0023] The absolute position pattern 63 of the third track 6C has a length L of 10.5 mm in the X direction. In this embodiment, the absolute position pattern 63 is disposed at the center of the plate 60 in the X direction. The absolute position pattern 63 is disposed at a position where the boundary between the south pole and north pole of one of the multiple unit patterns 62 coincides with the center of the absolute position pattern 63 in the X direction. In this embodiment, the boundary between the south pole and north pole of the central unit pattern 62 of the nine unit patterns 62 coincides with the center of the absolute position pattern 63 in the X direction.

[0024] (sensor unit) As shown in FIGS. 2 and 3, the sensor unit 8 includes a first sensor unit 8A, a second sensor unit 8B, and a third sensor unit 8C. The first sensor unit 8A, the second sensor unit 8B, and the third sensor unit 8C are provided on an elongated substrate 9 whose longitudinal direction is in the X direction and whose lateral direction is in the Y direction. The first sensor unit 8A is provided at an end of the substrate 9 in the Y1 direction. The second sensor unit 8B is provided at the center of the substrate 9 in the Y1 direction. The third sensor unit 8C is provided at an end of the substrate 9 in the Y2 direction.

[0025] The first sensor unit 8A is provided at a position facing the first track 6A of the scale 6. The first sensor unit 8A has a row of ID sensors 10 aligned in a line in the X direction at a pitch that is half the first pitch P1. In this embodiment, the arrangement pitch of the ID sensors 10 is 3 mm. Each ID sensor 10 has a Hall element and an A / D converter. When each ID sensor 10 faces the magnetized portion that constitutes each of the ID elements ID00, ID01, ID02, ..., ID07, it outputs a signal whose positive and negative polarities change depending on the polarity of the magnetized portion.

[0026] The plurality of ID sensors 10 includes two groups: a first group of ID sensors 11 and a second group of ID sensors 12. The first sensor unit 8A is configured by arranging the ID sensors 11 of the first group and the ID sensors 12 of the second group alternately.

[0027] The second sensor unit 8B is located opposite the second track 6B of the scale 6. The second sensor unit 8B includes an interpolation position sensor group 20 consisting of a plurality of Hall elements arranged in the X direction. The interpolation position sensor group 20 outputs one cycle of sine and cosine signals with a phase shift of π / 2 each time the unit pattern 62 of the second track 6B passes. In the example shown in FIG. 2, the interpolation position sensor group 20 includes two Hall elements 21A and 21B arranged at an arrangement pitch of ¼ the first pitch P1. In this embodiment, the distance between the two Hall elements 21A and 21B is 1.5 mm. Alternatively, the interpolation position sensor group 20 may be configured with four Hall elements arranged at a 1.5 mm pitch. When using four Hall elements, differential signals with a phase shift of π are combined to determine the sine and cosine signals.

[0028] As shown in FIG. 2 , in this embodiment, a plurality of interpolation position sensor groups 20 are arranged in the X direction at a second pitch P2 on one sensor unit 8. The length L2 of the sensor unit 8 in the X direction is 240 mm. The second pitch P2 is shorter than the length of the scale 6 in the X direction. For example, the second pitch P2 is 54 mm or 57 mm. As a result, when a plurality of movers 3 are arranged on the same sensor unit 8, each mover 3 faces one of the plurality of interpolation position sensor groups 20. When the length L2 of the sensor unit 8 is 240 mm and the second pitch P2 is 54 mm or 57 mm, the interpolation position sensor groups 20 are arranged at five locations on one sensor unit 8. Although the length L2 of the sensor unit 8 is four times the length L1 of the scale 6, if the position of the scale 6 is shifted so as to straddle adjacent sensor units 8, a maximum of five scales 6 face one sensor unit 8.

[0029] The third sensor unit 8C is provided at a position facing the third track 6C of the scale 6. The third sensor unit 8C has a row of absolute position sensors 30 lined up in a line in the X direction at a first pitch P1. As shown in FIGS. 2 and 3, each absolute position sensor 30 is assigned a number that increases sequentially from the X1 side to the X2 side. For example, in the example shown in FIGS. 2 and 3, the absolute position sensors 30 are numbered Z0 to Z39. Each absolute position sensor 30 has a Hall element and an A / D converter, and outputs a signal that switches between ON and OFF depending on whether or not there is a magnetized portion opposite it.

[0030] The third sensor unit 8C outputs an ON signal from the absolute position sensor 30 facing the absolute position pattern 63 of the third track 6C, and outputs an OFF signal from the other absolute position sensors 30. In this embodiment, the arrangement pitch of the absolute position sensors 30 is 6 mm, while the length of the absolute position pattern 63 in the X direction is 10.5 mm. Therefore, when the absolute position pattern 63 passes, an ON signal is output from two adjacent absolute position sensors 30, or from one absolute position sensor 30.

[0031] (Detection of absolute position information) The encoder 4 detects the absolute position of the scale 6 at low resolution using the third sensor unit 8C and the third track 6C. The third sensor unit 8C has absolute position sensors 30 arranged at a constant pitch in the X direction. Therefore, low-resolution position information can be obtained from the number of the absolute position sensor 30 that is outputting an ON signal. In this embodiment, the arrangement pitch of the absolute position sensors 30 is 6 mm, so position information with a resolution of 6 mm can be obtained.

[0032] In such low-resolution position detection, when the end of the absolute position pattern 63 faces the absolute position sensor 30, the signal from the absolute position sensor 30 is disturbed and is either ON or OFF. Therefore, in this embodiment, the length of the absolute position pattern 63 in the X direction is set to a length that allows it to face two adjacent absolute position sensors 30 at the same time. This makes it possible to detect an ON signal from at least one absolute position sensor 30. On the other hand, there may be cases where ON signals are detected from two absolute position sensors 30. When ON signals are output from two absolute position sensors 30, the data processing unit 7 determines the number of the absolute position sensor 30 to select by processing the flowchart in FIG. 6, which will be described later.

[0033] The encoder 4 uses the second sensor unit 8B and the second track 6B to detect, with high resolution, the interpolation position within the range of the length of one cycle of the unit pattern 62. The length of one cycle of the unit pattern 62 is 6 mm, which matches the arrangement pitch of the absolute position sensors 30. The data processing unit 7 calculates high-resolution absolute position information by combining the 6-mm resolution position information obtained from the output of the third sensor unit 8C and the high-resolution position information obtained from the output of the second sensor unit 8B.

[0034] FIG. 4 is an explanatory diagram of the process of calculating high-resolution position information from the signals of the interpolation position sensor group 20. The data processing unit 7 performs arctangent calculations based on the outputs (sine signal VA and cosine signal VB) of the Hall elements 21A and 21B. This results in a high-resolution position detection value. In this embodiment, the data processing unit 7 converts the sin signal VA and cosine signal VB for one period of the unit pattern 62 into a count value ranging from 0 to 5999. Hereinafter, this count value will be referred to as the "interpolation position AB." When the first pitch P1 is 6 mm, the interpolation position AB is position information with a resolution of 1 μm.

[0035] FIG. 5 is an explanatory diagram of the process of calculating absolute position information. FIG. 6 is a flowchart of the process of calculating absolute position information. As shown in FIG. 5, the data processing unit 7 repeats the process of calculating the interpolated position AB, which increases from 0 to 5999, every time the scale 6 moves 6 mm, which is the length of one period of the unit pattern 62, for the 0th period, the 1st period, the 2nd period, the 3rd period, and so on. As shown in FIG. 6, when the data processing unit 7 detects the absolute position information of the mover 3 using the encoder 4, it calculates the interpolated position AB at the detection timing (step ST11), and also acquires the number of absolute position sensors 30 that output an ON signal at the detection timing (hereinafter referred to as "numZON") (step ST12).

[0036] 5, the intervals in which the output of the absolute position sensor 30 is ON differ depending on the number of the absolute position sensor 30. From the size and arrangement of the absolute position pattern 63 described above, the intervals in which numZON becomes 1 are those centered around the timing when the value of the interpolation position AB becomes 3000. The data processing unit 7 determines whether numZON is 1, 2, or some other value (step ST13). If numZON=1, the number of the absolute position sensor 30 whose output is ON is set to "Zn" (step ST14).

[0037] If it is determined in step ST13 that numZON=2, the process proceeds to step ST15, where it is determined whether the value of the interpolated position AB is smaller than 3000. If AB<3000 (step ST15: Yes), of the two numbers of the absolute position sensors 30 whose output is ON, the larger number is set as "Zn" (step ST16). If AB≧3000 (step ST15: No), the smaller number is set as "Zn" (step ST17). Then, if numZON is a value other than 1 or 2, it is determined that a detection error has occurred (step ST18).

[0038] The data processing unit 7 stores a conversion table in which the numbers of the plurality of absolute position sensors 30 arranged in the third sensor unit 8C are associated with low-resolution absolute positions (hereinafter referred to as "absolute positions ZABS"). For example, the conversion table stores the number of the absolute position sensor 30, which is number 2, In this table, the value of the absolute position ZABS is set to 0, and thereafter, the absolute position ZABS increases by 6000 each time the number of the absolute position sensor 30 increases by 1. In this case, the absolute position ZABS may be calculated using the formula: ZABS=(Zn-2)×6000.

[0039] The data processing unit 7 extracts from the conversion table the value of the absolute position ZABS corresponding to the number Zn of the absolute position sensor 30 determined in steps ST14-16 (step ST19). Then, by combining the extracted absolute position ZABS with the interpolated position AB calculated in step ST11, a high-resolution absolute position (hereinafter referred to as the "absolute position ABS") is calculated. As shown in FIG. 6, when a conversion table is used in which the absolute position ZABS=0 when Zn=2, in step ST20, a predetermined position corresponding to the position of the absolute position sensor 30 numbered 2 is set as the reference position, and the absolute position in the X direction from the reference position is detected with a resolution of 1 μm. The conversion table can be changed as needed depending on the position to be used as the reference position for the absolute position.

[0040] (Detection of absolute positions of multiple movers) In the conveyance system 1, multiple interpolated position sensor groups 20 are arranged in one sensor unit 8. For example, as shown in FIG. 3, five interpolated position sensor groups 20A, 20B, 20C, 20D, and 20E are arranged in one sensor unit 8. Therefore, the data processing unit 7 calculates up to five interpolated positions AB from the output of one sensor unit 8. Then, for each of the five interpolated positions AB, numZON is acquired from the ranges of the different absolute position sensors 30. This detects the absolute positions of up to five movers 3 moving on one sensor unit 8. The data processing unit 7 can perform the absolute position calculation process shown in the flowchart of FIG. 6 for up to five movers 3 in parallel. Then, absolute position information for up to five movers 3 can be transmitted to a higher-level device at once.

[0041] The data processing unit 7 stores data associating different ranges of the absolute position sensors 30 with each of the five interpolated position sensor groups 20A, 20B, 20C, 20D, and 20E provided in one sensor unit 8. Each range can be, for example, the range of 19 absolute position sensors 30 corresponding to slightly less than twice the length of the scale 6. For example, in the correspondence table shown in FIG. 3, the interpolated position sensor group 20B is associated with numbers Z1 to Z19 of the absolute position sensors 30 in the same sensor unit 8M as the range of the absolute position sensors 30 for acquiring numZON.

[0042] (Detecting the absolute position of a mover across multiple sensor units) The conveyance system 1 is designed to have the mover 3 move across multiple sensor units 8. Therefore, for the interpolated position sensor group 20A located at the X1 end of the sensor unit 8M, the range of the absolute position sensor 30 for acquiring numZON is set to span the adjacent sensor units 8M and 8M-1. For example, in the correspondence table shown in FIG. 3, for the interpolated position sensor group 20A, the numbers Z0 to Z10 of the absolute position sensors 30 in the same sensor unit 8M correspond to the numbers Z32 to Z39 of the absolute position sensors 30 in the adjacent sensor unit 8M-1. A similar setting can be made for the interpolated position sensor group 20E located at the X2 end. This allows the absolute position of the mover 3 to be detected even when spanning multiple sensor units 8.

[0043] (Identification detection) The encoder 4 uses the first sensor unit 8A and the first track 6A to detect different identification information for each mover 3. In this embodiment, the identification information is calculated using the value of Zn indicating the low-resolution absolute position used in the calculation of the absolute position information, and the value of the high-resolution interpolated position AB.

[0044] FIG. 7 is an explanatory diagram of the process of calculating the identification information. FIG. 8 is an explanatory diagram of the process of calculating the identification information. 1 is a flowchart. The range of the ID sensor 10 that reads the ID pattern 61 can be determined from the value of Zn, which indicates a low-resolution absolute position. The data processing unit 7 stores an ID data extraction range table that associates the value of Zn with the range of the ID sensor 10.

[0045] As shown in FIG. 7, the row of ID sensors 10 alternates between the ID sensors 11 of the first group and the ID sensors 12 of the second group. A common data extraction range is set in the ID data extraction range table for each of these two groups. For example, as shown in FIG. 8, when Zn=2, the range from 0 to 7 is set as the data extraction range. This range corresponds to the number of detectable elements constituting the ID pattern 61 being 8. Therefore, the range from 0 to 7 is the data extraction range for each of the ID sensors 11 of the first group and the ID sensors 12 of the second group. This corresponds to the range from H0 to H7 shown in FIG. 7. H0, H2, and H7 shown in FIG. 7 represent pairs of adjacent ID sensors 11 and 12.

[0046] The ID data extraction range table is set so that the data extraction range shifts by 1 each time Zn increases by 1. For example, if Zn=3, the range from 1 to 8 is set, and if Zn=4, the range from 2 to 9 is set.

[0047] As shown in FIG. 8, when the data processing unit 7 detects the identification information of the mover 3 using the encoder 4, it refers to the ID data extraction range table using Zn used to detect the absolute position information, and extracts data of the ID sensor 10 within the range in which the ID pattern 61 can be read (step ST21).

[0048] Next, proceed to step ST22 and determine whether the value of the interpolation position AB is less than 3000. As shown in FIG. 7, the ID sensors 11 of the first group and the ID sensors 12 of the second group are offset in the X direction by half the first pitch P1. Therefore, the timing at which the same detection element (magnetized portion) is detected is offset by half the period in which the interpolation position AB changes from 1 to 5999. Therefore, even if the signal of one of the pair of adjacent ID sensors 11 and 12 is disturbed when it passes through the boundary between the adjacent detection elements, the other sensor faces the center of the detection element at that time and can output a normal signal. The data processing unit 7 determines whether the value of the interpolation position AB is less than 3000 and determines whether the ID sensor 11 of the first group or the ID sensor 12 of the second group can output a normal signal.

[0049] If AB<3000 (step ST22: Yes), the data processing unit 7 adopts the detection data of the ID sensor 11 of the first group (step ST23). That is, the detection data of the ID sensor 11 is adopted for all pairs of H0, H2, H7. On the other hand, if AB≧3000 (step ST22: No), the detection data of the ID sensor 12 of the second group is adopted (step ST24). For example, when Zn=2, the detection data of the ID sensor 12 is adopted for all pairs of H0, H2, H7. Then, the process proceeds to step ST25, where identification information is determined from the adopted data. For example, the identification information is determined to be composed of an 8-digit binary signal.

[0050] (Main effects of this embodiment) As described above, the encoder 4 of this embodiment has the sensor unit 5, the scale 6 that moves relatively to the sensor unit 5, and the data processing unit 7 that calculates absolute position information and identification information of the scale 6 using a signal from the sensor unit 5. The scale 6 has a first track 6A on which an ID pattern 61 is arranged in the X direction, where ID elements ID00, ID01, ID02, ... ID07 are detectable elements; a second track 6B on which a periodic pattern is arranged in the X direction, where unit patterns 62 each consisting of a pair of different detectable elements are repeatedly arranged at a first pitch P1; and a third track 6C on which an absolute position pattern 63 composed of detection elements is arranged. The sensor unit 5 includes a first sensor unit 8A facing the first track 6A and including a row of ID sensors 10 lined up in the X direction; a second sensor unit 8B facing the second track 6B and including an interpolation position sensor group 20 that outputs one cycle of sine and cosine signals with a phase shift of π / 2 each time a unit pattern 62 passes; and a third sensor unit 8C facing the third track 6C and including a row of absolute position sensors 30 lined up in the X direction at a first pitch P1. The data processing unit 7 calculates absolute position information using low-resolution position information obtained from signals from the absolute position sensors 30 that detect the absolute position pattern 63 and high-resolution position information obtained from the sine and cosine signals. Furthermore, the data processing unit 7 determines the range of the ID sensors 10 in the row that detects the ID pattern 61 using the low-resolution position information, and calculates identification information using signals from the ID sensors 10 in the determined range.

[0051] As described above, in this embodiment, even if the dimensions of the absolute position pattern 63 or the arrangement pitch of the absolute position sensors 30 are coarse, high-resolution absolute position information can be calculated by combining high-resolution position information calculated using the interpolated position sensor group 20 and the periodic pattern. This reduces the computational load, and inexpensive elements such as Hall elements can be used as detection elements rather than MR elements. Furthermore, the range of the ID sensor 10 for detecting the ID pattern 61 can be appropriately determined using low-resolution position information obtained from the absolute position pattern 63 and the absolute position sensor 30. This reduces the amount of data handled in the computation of the identification information, thereby reducing the computational load. Furthermore, inexpensive elements such as Hall elements can be used to detect the identification information. Therefore, an encoder with an identification information detection function that can detect identification information and absolute position information can be configured to have high resolution yet be inexpensive.

[0052] In this embodiment, the length of the absolute position pattern 63 in the X direction is longer than the first pitch P1 but shorter than twice the first pitch P1. When calculating absolute position information, the data processing unit 7 determines, based on the high-resolution position information, which of the signals from two adjacent absolute position sensors 30 that detected the absolute position pattern 63 to use. By adjusting the dimensions of the absolute position pattern 63 so that it simultaneously faces two absolute position sensors 30, detection errors caused by signal disturbances when the absolute position sensor 30 passes the end of the absolute position pattern 63 can be reduced. Furthermore, even if two absolute position sensors 30 are simultaneously turned on, it is possible to appropriately determine which sensor to select based on the value of the high-resolution position information. Therefore, detection errors can be reduced despite an inexpensive configuration.

[0053] In this embodiment, the ID pattern 61 is configured by arranging detectable elements at a first pitch P1. The row of ID sensors 10 is configured by arranging first group ID sensors 11 and second group ID sensors 12 alternately at a pitch half the first pitch P1. When reading each detectable element constituting the ID pattern 61, the data processing unit 7 determines, based on high-resolution position information, whether to use the signal from the first group ID sensor 11 or the second group ID sensor 12 of the signals from two adjacent ID sensors 10 facing the detectable element. This reduces detection errors caused by signal disturbances when the ID sensor 10 passes through the boundary between the detectable elements constituting the ID pattern 61. Therefore, detection errors can be reduced despite the low cost configuration.

[0054] In this embodiment, the detectable elements constituting the ID pattern 61 are magnetized parts magnetized to either the north pole or the south pole. The ID sensor 10 is a Hall element. Furthermore, the unit pattern 62 is formed by arranging a magnetized part magnetized to the north pole and a magnetized part magnetized to the south pole in the X direction. The interpolation position sensor group 20 is two or four Hall elements arranged at a pitch of 1 / 4 of the first pitch P1. Furthermore, the absolute position pattern 63 is one magnetized part magnetized to either the north pole or the south pole. The absolute position sensor 30 is a Hall element. In this way, the magnetic detection method is adopted. This is advantageous for miniaturization and allows for a low-cost configuration.

[0055] In this embodiment, the sensor section 5 includes at least one sensor unit 8, in which a first sensor section 8A, a second sensor section 8B, and a third sensor section 8C are arranged in a direction intersecting the X direction on a substrate 9 extending in the X direction. The sensor unit 8 includes a plurality of interpolated position sensor groups 20 arranged in the X direction at a second pitch P2 shorter than that of the scale 6, a plurality of ID sensors 10 arranged at an arrangement pitch that is half the first pitch P1 across the entire range of the substrate 9 in the X direction, and a plurality of absolute position sensors 30 arranged at the first pitch P1 across the entire range of the substrate 9 in the X direction. Combining the sensor section 5 into a unit in this way makes it convenient to construct the conveyance system 1. Furthermore, by making the arrangement pitch of the interpolated position sensor groups 20 shorter than that of the scale 6, the positions of many movers 3 can be detected simultaneously.

[0056] In this case, low-resolution position information is calculated using data in which the range of the absolute position sensor 30 that detects the absolute position pattern 63 is previously associated with each of the multiple interpolated position sensor groups 20. In this way, the amount of data handled in detecting the absolute position can be reduced, thereby reducing the calculation load.

[0057] In this embodiment, a plurality of sensor units 8 are lined up in the X direction, and some of the plurality of interpolated position sensor groups 20 are set so that the range of the absolute position sensor 30 that detects the absolute position pattern 63 straddles adjacent sensor units 8. In this way, even if the mover 3 moves to a position that straddles a plurality of sensor units 8, highly accurate position detection can be performed.

[0058] (Other embodiments) (1) In the above embodiment, the range of the ID sensor 10 that detects the ID pattern 61 is determined using the position information when calculating the absolute position information. However, as will be described below, the range of the ID sensor 10 that detects the ID pattern 61 does not have to be determined using the position information.

[0059] Another embodiment of the encoder 4 with identification information detection function has a sensor unit 5, a scale 6 that moves relatively to the sensor unit 5, and a data processing unit 7 that calculates absolute position information and identification information of the scale 6 using a signal from the sensor unit 5. The scale 6 includes a first track 6A on which an ID pattern 61 in which detectable elements are arranged in the X direction is arranged, a second track 6B on which a periodic pattern in which unit patterns 62 made of pairs of different detectable elements are repeatedly arranged in the X direction at a first pitch P1 is arranged, and a third track 6C on which an absolute position pattern 63 made of detectable elements that is longer than the first pitch P1 but shorter than twice the first pitch P1 is arranged. The sensor unit 5 includes a first sensor unit 8A facing the first track 6A and including a row of ID sensors 10 lined up in the X direction, a second sensor unit 8B facing the second track 6B and including an interpolation position sensor group 20 that outputs one period of sine and cosine signals whose phases are shifted by π / 2 each time a unit pattern 62 passes, and a third sensor unit 8C facing the third track 6C and including a row of absolute position sensors 30 lined up in the X direction at a first pitch P1. When calculating absolute position information using low-resolution position information obtained from the signals of the absolute position sensors 30 that detected the absolute position pattern 63 and high-resolution position information obtained from the sine and cosine signals, the data processing unit 7 determines, based on the high-resolution position information, which of the signals of two adjacent absolute position sensors 30 that detected the absolute position pattern 63 to use.

[0060] In this embodiment, similar to the above embodiment, even if the dimensions of the absolute position pattern 63 or the arrangement pitch of the absolute position sensors 30 are coarse, high-resolution absolute position information can be calculated by combining high-resolution position information calculated using the interpolation position sensor group 20 and the periodic pattern. Therefore, the calculation load is small, and it is possible to use a Hall element or the like as the detection element instead of an MR element. Inexpensive elements can be used. Furthermore, detection errors caused by signal disturbances when the absolute position sensor 30 passes over the end of the absolute position pattern 63 can be suppressed, and even if two absolute position sensors 30 are turned on at the same time, it is possible to appropriately determine which one to select. Therefore, an encoder with an identification information detection function that can detect identification information and absolute position information can be configured to have high resolution, few detection errors, and be inexpensive.

[0061] (2) The above-mentioned embodiment is a magnetic detection type encoder, but it can also be an optical type encoder. That is, the detected element can be an optical pattern such as light passing through a slit, and the sensor can be a light receiving unit. Alternatively, it can be an electromagnetic induction type encoder that uses an induction coil instead of the magnetic field of a magnet.

[0062] (3) The specific dimensions of each part described in the above embodiment can be changed as appropriate. For example, the arrangement pitch of the unit patterns 62 is not limited to 6 mm. Furthermore, the size of the absolute position pattern 63 does not have to be 10.5 mm as long as it is large enough to face two absolute position sensors 30 at the same time. For example, it may be 9 mm.

[0063] (4) In the above embodiment, multiple movable elements 3 can be detected on one sensor unit 8, but the number of movable elements 3 that can be detected on one sensor unit 8 can be as small as one or any number.

[0064] (summary) A summary of this disclosure is provided below. (1) a sensor unit, a scale that moves relatively to the sensor unit, and a data processing unit that calculates absolute position information and identification information of the scale using a signal from the sensor unit, The scale is a first track on which an ID pattern is arranged, in which elements to be detected are arranged in the moving direction of the scale relative to the sensor unit; a second track on which a periodic pattern is arranged, in which unit patterns each consisting of a different pair of the detection elements are repeatedly arranged at a first pitch in the movement direction; a third track on which an absolute position pattern made up of the detected elements is arranged, The sensor unit a first sensor unit facing the first track and including a row of ID sensors aligned in the moving direction; a second sensor unit facing the second track and including an interpolation position sensor group that outputs a sine signal and a cosine signal whose phases are shifted by π / 2 for one period each time the unit pattern passes; a third sensor unit facing the third track and including a row of absolute position sensors aligned at the first pitch in the movement direction; The data processing unit calculating the absolute position information using low-resolution position information obtained from a signal of the absolute position sensor that detected the absolute position pattern and high-resolution position information obtained from the sine signal and the cosine signal; an encoder with an identification information detection function, wherein the range of the ID sensors in the row of ID sensors that detect the ID pattern is determined using the low-resolution position information, and the identification information is calculated using signals from the ID sensors in the determined range.

[0065] (2) a length of the absolute position pattern in the movement direction is longer than the first pitch and shorter than twice the first pitch; The data processing unit The encoder with identification information detection function described in (1) above, characterized in that when calculating the absolute position information, it is determined which of the signals from the two adjacent absolute position sensors that detected the absolute position pattern to use based on the high-resolution position information.

[0066] (3) the ID pattern is configured by arranging the detection elements at the first pitch, the row of ID sensors is configured by arranging the ID sensors of a first group and the ID sensors of a second group alternately at a pitch that is half the first pitch; The data processing unit The encoder with identification information detection function described in (1) or (2) above is characterized in that when reading each of the detectable elements that make up the ID pattern, it is determined, based on the high-resolution position information, whether to use the signal from the ID sensor of the first group or the signal from the ID sensor of the second group, out of the signals from the two adjacent ID sensors that face the detectable element.

[0067] (4) The detection element constituting the ID pattern is a magnetized portion magnetized to either an N pole or an S pole, The encoder with an identification information detection function according to any one of (1) to (3) above, wherein the ID sensor is a Hall element.

[0068] (5) The unit pattern is configured by arranging a magnetized portion magnetized to an N pole and a magnetized portion magnetized to an S pole in the moving direction, The encoder with identification information detection function described in any one of (1) to (4) above is characterized in that the interpolation position sensor group is two or four Hall elements arranged at a pitch of 1 / 4 of the first pitch.

[0069] (6) the absolute position pattern is one magnetized portion magnetized to either an N pole or an S pole, The encoder with an identification information detection function according to any one of (1) to (5) above, wherein the absolute position sensor is a Hall element.

[0070] (7) the sensor unit includes at least one sensor unit in which the first sensor unit, the second sensor unit, and the third sensor unit are arranged on a substrate extending in the movement direction in a direction intersecting the movement direction; The sensor unit includes: a group of the interpolation position sensors arranged in the movement direction at a second pitch shorter than the scale; a plurality of the ID sensors arranged at an arrangement pitch that is half the first pitch over the entire range of the movement direction of the substrate; The encoder with identification information detection function described in any one of (1) to (6) above, characterized in that it comprises a plurality of absolute position sensors arranged at the first pitch over the entire range of the movement direction of the substrate.

[0071] (8) The low-resolution position information is calculated using data in which the range of the absolute position sensor that detects the absolute position pattern is previously associated with each of the plurality of interpolation position sensor groups. The encoder with an identification information detection function according to (7) above, characterized in that it calculates

[0072] (9) a plurality of the sensor units are arranged in the movement direction, The encoder with identification information detection function described in (7) or (8) above is characterized in that, in some of the plurality of interpolated position sensor groups, the range of the absolute position sensor that detects the absolute position pattern is set so as to straddle the adjacent sensor units.

[0073] (10) a sensor unit, a scale that moves relatively to the sensor unit, and a data processing unit that calculates absolute position information and identification information of the scale using a signal from the sensor unit, The scale is a first track on which an ID pattern is arranged, in which elements to be detected are arranged in the moving direction of the scale relative to the sensor unit; a second track on which a periodic pattern is arranged, in which unit patterns each consisting of a different pair of the detection elements are repeatedly arranged at a first pitch in the movement direction; a third track on which an absolute position pattern made up of the detected elements, the absolute position pattern being longer than the first pitch and shorter than twice the first pitch, is arranged; The sensor unit a first sensor unit facing the first track and including a row of ID sensors aligned in the moving direction; a second sensor unit facing the second track and including an interpolation position sensor group that outputs a sine signal and a cosine signal whose phases are shifted by π / 2 for one period each time the unit pattern passes; a third sensor unit facing the third track and including a row of absolute position sensors aligned at the first pitch in the movement direction; The data processing unit an encoder with identification information detection function, characterized in that when calculating the absolute position information using low-resolution position information obtained from the signal of the absolute position sensor that detected the absolute position pattern and high-resolution position information obtained from the sine signal and the cosine signal, it is determined which of the signals of two adjacent absolute position sensors that detected the absolute position pattern to use based on the high-resolution position information. [Explanation of symbols]

[0074] 1...Transport system, 2...Rail, 3...Movers, 4...Encoder with identification information detection function, 5...Sensor section, 6...Scale, 6A...First track, 6B...Second track, 6C...Third track, 7...Data processing section, 8, 8M, 8M-1, 8M+1...Sensor unit, 8A...First sensor section, 8B...Second sensor section, 8C...Third sensor section, 9...Substrate, 10...ID sensor, 11...First group of ID sensors, 12...Second group of ID sensors, 20, 20A, 20B, 20C, 20D, 20E...Interpolation position sensor group, 21A, 21B...Hall element, 30...Absolute position sensor, 60...Plate, 61...ID pattern, 62...Unit pattern, 63...Absolute position pattern

Claims

1. a sensor unit, a scale that moves relatively to the sensor unit, and a data processing unit that calculates absolute position information and identification information of the scale using a signal from the sensor unit, The scale is a first track on which an ID pattern is arranged, in which elements to be detected are arranged in a moving direction of the scale relative to the sensor unit; a second track on which a periodic pattern is arranged, in which unit patterns each consisting of a different pair of the detection elements are repeatedly arranged at a first pitch in the moving direction; a third track on which an absolute position pattern made up of the detected elements is arranged, The sensor unit a first sensor unit facing the first track and including a row of ID sensors aligned in the moving direction; a second sensor unit facing the second track and including an interpolation position sensor group that outputs a sine signal and a cosine signal, the phases of which are shifted by π / 2, for one period each time the unit pattern passes; a third sensor unit facing the third track and including a row of absolute position sensors aligned at the first pitch in the movement direction; The data processing unit calculating the absolute position information using low-resolution position information obtained from a signal of the absolute position sensor that detected the absolute position pattern and high-resolution position information obtained from the sine signal and the cosine signal; An encoder with an identification information detection function, characterized in that a range of the ID sensors in the row of ID sensors that detects the ID pattern is determined using the low-resolution position information, and the identification information is calculated using signals from the ID sensors in the determined range.

2. a length of the absolute position pattern in the movement direction is longer than the first pitch and shorter than twice the first pitch; The data processing unit 2. The encoder with identification information detection function according to claim 1, wherein when calculating the absolute position information, it is determined which of the signals from the two adjacent absolute position sensors that detected the absolute position pattern to use based on the high-resolution position information.

3. the ID pattern is configured by arranging the detection elements at the first pitch, the row of ID sensors is configured by arranging the ID sensors of a first group and the ID sensors of a second group alternately at a pitch that is half the first pitch, The data processing unit The encoder with identification information detection function according to claim 1, characterized in that when reading each of the detectable elements that constitute the ID pattern, it is determined, based on the high-resolution position information, whether to use the signal from the ID sensor of the first group or the signal from the ID sensor of the second group, out of the signals from two adjacent ID sensors facing the detectable element.

4. The detection element constituting the ID pattern is a magnetized portion magnetized to either an N pole or an S pole, 2. The encoder with an identification information detection function according to claim 1, wherein the ID sensor is a Hall element.

5. The unit pattern is configured by arranging a magnetized portion magnetized to an N pole and a magnetized portion magnetized to an S pole in the moving direction, 2. The encoder with identification information detection function according to claim 1, wherein the group of interpolation position sensors is two or four Hall elements arranged at a pitch that is 1 / 4 of the first pitch.

6. the absolute position pattern is one magnetized portion magnetized to either an N pole or an S pole, 2. The encoder with an identification information detection function according to claim 1, wherein the absolute position sensor is a Hall element.

7. the sensor unit includes at least one sensor unit in which the first sensor unit, the second sensor unit, and the third sensor unit are arranged on a substrate extending in the movement direction in a direction intersecting the movement direction; The sensor unit includes: a group of the interpolation position sensors arranged in the movement direction at a second pitch shorter than the scale; a plurality of the ID sensors arranged at an arrangement pitch that is half the first pitch over the entire range of the movement direction of the substrate; 2. The encoder with identification information detection function according to claim 1, further comprising: a plurality of the absolute position sensors arranged at the first pitch over the entire range of the movement direction of the substrate.

8. 8. The encoder with identification information detection function according to claim 7, wherein the low-resolution position information is calculated using data in which the range of the absolute position sensor that detects the absolute position pattern is previously associated with each of the plurality of interpolation position sensor groups.

9. a plurality of the sensor units are arranged in the movement direction, 8. The encoder with identification information detection function according to claim 7, wherein a part of the plurality of interpolation position sensor groups is set so that the range of the absolute position sensor that detects the absolute position pattern straddles the adjacent sensor units.

10. a sensor unit, a scale that moves relatively to the sensor unit, and a data processing unit that calculates absolute position information and identification information of the scale using a signal from the sensor unit, The scale is a first track on which an ID pattern is arranged, in which elements to be detected are arranged in a moving direction of the scale relative to the sensor unit; a second track on which a periodic pattern is arranged, in which unit patterns each consisting of a different pair of the detection elements are repeatedly arranged at a first pitch in the moving direction; a third track on which an absolute position pattern made up of the detected elements, the absolute position pattern being longer than the first pitch and shorter than twice the first pitch, is arranged; The sensor unit a first sensor unit facing the first track and including a row of ID sensors aligned in the moving direction; a second sensor unit facing the second track and including an interpolation position sensor group that outputs a sine signal and a cosine signal, the phases of which are shifted by π / 2, for one period each time the unit pattern passes; a third sensor unit facing the third track and including a row of absolute position sensors aligned at the first pitch in the movement direction; The data processing unit When calculating the absolute position information using low-resolution position information obtained from the signal of the absolute position sensor that detected the absolute position pattern and high-resolution position information obtained from the sine signal and the cosine signal, it is determined which of the signals of the two adjacent absolute position sensors that detected the absolute position pattern to use based on the high-resolution position information. An encoder with an identification information detection function, characterized in that

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