JP2023128398A - Positioning device, drive device, positioning method and positioning program - Google Patents

Abstract

To provide a positioning device and the like which can surely detect a reference mark provided in a movable element.SOLUTION: A positioning device 4 includes: a plurality of magnetic sensors S1-S5 which are arranged along the movement direction of a movable element for positioning magnetic scales C1, C2 attached to the movable element, have an interval thereof smaller than the length in the movement direction of the magnetic scales C1, C2 and specify a reference position of the movable element by detecting reference marks Z1, Z2 provided in the movable element; and a reference mark detection validation unit 41 which validates detection of the reference marks Z1, Z2 with the other magnetic sensor when moving to the outside of a detection range of one magnetic sensor from a state where the magnetic scales C1, C2 straddle the detection range of the two adjacent magnetic sensors S1/S2, S2/S3, S3/S4, S4/S5.SELECTED DRAWING: Figure 2

Description

The present invention relates to a drive device and the like that move a movable element along a track.

Patent Document 1 discloses a linear conveyance system as a drive device that moves a movable element along a track. A plurality of magnetic sensors arranged along the trajectory position a magnetic scale (ie, a movable element) attached to a movable element. The magnetic sensor can identify the reference position of the movable element by detecting a reference mark provided on the movable element.

Japanese Patent Application Publication No. 2021-164396

In the linear conveyance system of Patent Document 1, the interval between the plurality of magnetic sensors is smaller than the length of the magnetic scale in the orbit direction. Therefore, one magnetic scale (ie, movable element) may straddle the detection ranges of two adjacent magnetic sensors. Furthermore, when a plurality of movers are present, two different magnetic scales (ie movers) may simultaneously enter the detection range of two adjacent magnetic sensors. Even in such a complicated case, the magnetic sensor must be able to reliably detect each reference mark and identify the movable element on which each reference mark is provided.

The present invention has been made in view of these circumstances, and it is an object of the present invention to provide a positioning device and the like that can reliably detect a reference mark provided on a movable element.

In order to solve the above problems, a positioning device according to an aspect of the present invention includes a plurality of position detection units arranged along the moving direction of the movable element in order to position a positioning scale attached to the movable element. , a plurality of position detection units whose intervals are smaller than the length of the positioning scale in the moving direction and which identify the reference position of the movable element by detecting reference marks provided on the movable element; and a positioning scale that is located at two adjacent positions. a reference mark detection enabling unit that enables detection of the reference mark by the other position detection unit when the position detection unit moves outside the detection range of one of the position detection units from a state where the detection unit straddles the detection range of the detection unit; Be prepared.

In this aspect, when the positioning scale moves from a state where it straddles the detection ranges of two adjacent position detection units to outside the detection range of one position detection unit, the reference mark cannot be detected by the other position detection unit. Enabled. For example, when multiple movers (i.e. positioning scales) are present, even if two different positioning scales enter the detection range of two adjacent position detection units at the same time, the detection of the fiducial mark will not be enabled in that state. Therefore, false detection of the fiducial mark can be prevented.

Another aspect of the invention is a drive device. This device consists of a plurality of movable elements that are driven along a trajectory, and a plurality of position detection sections that are arranged along the trajectory to measure positioning scales attached to each movable element. A plurality of position detection units each detecting a reference mark provided on each movable element, which is smaller than the length of the scale in the orbital direction, identify the reference position of each movable element, and a positioning scale is connected to two adjacent position detection elements. A reference mark detection enabling unit is provided that enables the detection of the reference mark by the other position detection unit when the detection range of one of the position detection units moves outside the detection range of the detection range.

Yet another aspect of the present invention is a positioning method. This method includes a plurality of position detection units arranged along the moving direction of the movable element to measure the position of a positioning scale attached to the movable element, the interval between them being smaller than the length of the positioning scale in the moving direction, In a positioning device that includes a plurality of position detection units that identify the reference position of a movable element by detecting a reference mark provided on the movable element, the positioning scale straddles the detection range of two adjacent position detection units. A reference mark detection enabling step is provided for enabling detection of the reference mark by the other position detection unit when the position detection unit moves out of the detection range of one of the position detection units.

Note that the present invention also includes arbitrary combinations of the above-mentioned constituent elements and conversion of these expressions into methods, devices, systems, recording media, computer programs, and the like.

According to the present invention, the reference mark provided on the movable element can be reliably detected.

FIG. 1 is a perspective view showing the overall structure of a linear conveyance system. 1 schematically shows a positioning device configured by a position detection unit and a positioning scale in a linear conveyance system. This figure schematically shows how the positioning subject of a moving magnetic scale is switched from a source magnetic sensor to a destination magnetic sensor. An embodiment will be described in which the reference mark detection enabling section and/or the reference mark detection disabling section are not used. An embodiment will be described in which the reference mark detection enabling section and/or the reference mark detection disabling section are not used. An embodiment using a fiducial mark detection enabling section and/or a fiducial mark detection disabling section will be described. An embodiment using a fiducial mark detection enabling section and/or a fiducial mark detection disabling section will be described. This diagram schematically shows a state in which two magnetic scales that have approached to the minimum approachable distance are simultaneously within the detection range of one magnetic sensor. A first example in which a plurality of movers are moving at a constant speed is shown. A first example in which a plurality of movers are moving at a constant speed is shown. A second embodiment is shown in which a plurality of movers are moving at a constant speed. A second embodiment is shown in which a plurality of movers are moving at a constant speed. A third embodiment is shown in which a plurality of movers are moving at a constant speed. A third embodiment is shown in which a plurality of movers are moving at a constant speed.

Hereinafter, modes for carrying out the present invention (hereinafter also referred to as embodiments) will be described in detail with reference to the drawings. In the description and/or drawings, the same or equivalent components, members, processes, etc. are denoted by the same reference numerals, and redundant description will be omitted. The scales and shapes of the parts shown in the drawings are set for convenience to simplify the explanation, and should not be interpreted in a limited manner unless otherwise stated. The embodiments are illustrative and do not limit the scope of the present invention. Not all features or combinations thereof described in the embodiments are necessarily essential to the present invention.

FIG. 1 is a perspective view showing the overall structure of a linear conveyance system 1, which is one embodiment of a drive device according to the present invention. The linear conveyance system 1 includes a stator 2 that constitutes an annular rail or track, and a plurality of movers 3A, 3B, 3C, and 3D (hereinafter referred to as movable (collectively referred to as Child 3). An electromagnet or coil provided on the stator 2 and a permanent magnet provided on the mover 3 face each other to form a linear motor along an annular rail. Note that the rail formed by the stator 2 may have any shape, not limited to an annular shape. For example, the rail may be straight or curved, one rail may branch into multiple rails, or multiple rails may merge into one rail. Furthermore, the installation direction of the rails formed by the stator 2 is also arbitrary. In the example of FIG. 1, the rails are arranged in a horizontal plane, but the rails may also be arranged in a vertical plane, It may be arranged within the plane of the corner or within the curved surface.

The stator 2 has a rail surface 21 whose normal direction is the horizontal direction. The rail surface 21 extends in a band shape along the rail formation direction, and when forming an annular rail as in the example of FIG. 1, it becomes an endless band shape with (imaginary) both ends connected. A plurality of drive modules (not shown) including electromagnets are embedded or arranged continuously or periodically along the rail on the rail surface 21, which can form a rail of any shape in this way. The electromagnets in the drive module generate a magnetic field that exerts a propulsion force along the rail on the permanent magnets of the armature 3 and/or on the electromagnets themselves. Specifically, when a driving current such as a three-phase alternating current is passed through these many electromagnets, a moving magnetic field is generated that linearly drives the mover 3 including the permanent magnets in a desired tangential direction along the rail. In the example of FIG. 1, the normal direction of the rail surface 21 that forms the annular rail in the horizontal plane is the horizontal direction, but the normal direction of the rail surface 21 may be the vertical direction or any other arbitrary direction.

In the stator 2, a positioning section 22 provided on the upper or lower surface perpendicular to the rail surface 21 stores the position of a magnetic scale (not shown in FIG. 1) as a positioning target or positioning scale attached to the movable element 3. A plurality of magnetic sensors (not shown in FIG. 1) serving as measurable position detection units are buried continuously or periodically. A magnetic sensor whose positioning target is a magnetic scale formed by a striped magnetic pattern or a magnetic scale with a constant pitch generally includes a plurality of magnetic detection heads. By shifting the intervals between the plurality of magnetic detection heads with respect to the pitch or period of the magnetic pattern of the magnetic scale, the magnetic sensor can measure the position of the magnetic scale with high precision. In a typical magnetic sensor provided with two magnetic detection heads, for example, the interval between the two magnetic detection heads is shifted by 1/4 pitch (the phase is shifted by 90 degrees) with respect to the magnetic pattern of the magnetic scale. Note that, contrary to the above, the movable element 3 may be provided with a magnetic sensor, and the stator 2 may be provided with a magnetic scale. Further, by differentiating the position of the movable element 3 measured by the positioning section 22 with respect to time, the velocity of the movable element 3 can be detected, and by differentiating the velocity with respect to time, the acceleration of the movable element 3 can be detected.

The position detection unit provided on the stator 2 and the positioning target or positioning scale attached to the movable element 3 are not limited to the above magnetic type, but may be optical or other types. In the case of an optical type, an optical scale formed by a striped pattern or graduations with a constant pitch is attached to the movable element 3, and an optical sensor that can optically read the striped pattern of the optical scale is provided to the stator 2. In the magnetic type and optical type, since the position detection unit measures the positioning target (magnetic scale or optical scale) without contact, the object being conveyed by the mover 3 scatters and the positioning point (the top surface of the stator 2) It is possible to reduce the risk of failure of the position detection unit if the device enters the room. However, with optical methods, positioning accuracy deteriorates if the optical scale is covered by conveyed objects such as liquids and powders that have entered the positioning point, so if the conveyed object has negligible magnetism, it will It is preferable to use a magnetic type that does not deteriorate positioning accuracy.

The movable element 3 includes a movable element body 31 facing the rail surface 21 of the stator 2, a positioning target part 32 extending horizontally from the upper part of the movable element body 31 and facing the positioning part 22 of the stator 2, and On the opposite side to the positioning section 32 (on the side far from the stator 2), there is provided a transport section 33 that extends horizontally from the movable element main body 31 and on which an object to be transported is placed or fixed. The mover main body 31 includes one or more permanent magnets (not shown) that face a plurality of electromagnets embedded in the rail surface 21 of the stator 2 along the rail. Since the moving magnetic field generated by the electromagnet of the stator 2 applies linear power or propulsion force in the tangential direction of the rail to the permanent magnet and/or the electromagnet itself of the mover 3, the mover 3 moves toward the rail surface 21 with respect to the stator 2. is driven in a straight line along the

The positioning target part 32 of the mover 3 has a magnetic scale or an optical scale as a positioning target or a positioning scale so as to face a position detection part (magnetic sensor or optical sensor) provided in the positioning part 22 of the stator 2. provided. In the example of FIG. 1 in which the position detection section is provided on the upper surface of the stator 2, a positioning target such as a magnetic scale is attached to the lower surface of the positioning target section 32 of the movable element 3. When the positioning unit 22 and the positioning target unit 32 are magnetic, the magnetic field between the electromagnet of the rail surface 21 and the permanent magnet of the mover main body 31 does not affect the magnetic positioning of the positioning unit 22 and the positioning target unit 32. In the stator 2, it is preferable that the rail surface 21 and the positioning part 22 are formed on different surfaces or in separate locations, and in the movable element 3, the movable body 31 and the positioning part 32 are preferably formed in different surfaces or in separate locations. .

Although four movers 3A, 3B, 3C, and 3D are illustrated in FIG. 1, for example, in a linear conveyance system 1 that conveys a large number of small objects, more than 1,000 movers 3 may be required. is assumed. In such a case, a situation frequently occurs in which two different positioning scales (that is, movable element 3) simultaneously enter the detection range of two adjacent position detection sections. Furthermore, there is a possibility that two movers 3 (that is, positioning scales) that are close to each other may simultaneously enter the detection range of one position detection section. Even in such a complicated case, each position detection unit must be able to reliably detect the reference marks of the mover 3 described below and uniquely identify the mover 3 on which each reference mark is provided. No.

FIG. 2 schematically shows a positioning device 4 including a position detection section and a positioning scale in the linear conveyance system 1. The positioning device 4 uses a fixed magnetic scale (hereinafter also referred to as magnetic scales C1 and C2 for convenience) as a positioning scale attached to a plurality of (two in the illustrated example) movers C1 and C2. A plurality of (in the illustrated example, five) magnetic sensors as position detection units are embedded or arranged in the rail surface 21 along the orbital direction of the child 2 or the movement direction of the movers C1 and C2 (left-right direction in FIG. 2). It includes S1 to S5.

Although the intervals in the moving direction of the magnetic sensors S1 to S5 may be different from each other, in this embodiment, an example in which all the intervals are equal will be described. In this case, the distance between the magnetic sensors S1 to S5 in the moving direction is, for example, 30 mm. Further, the lengths of the magnetic scales C1 and C2 in the moving direction may also be different from each other, but in this embodiment, an example in which all lengths are equal will be described. In this case, the length of each magnetic scale C1, C2 in the moving direction is, for example, 48 mm. As described above, in this embodiment, the interval (30 mm) between each of the magnetic sensors S1 to S5 in the moving direction is smaller than the length (48 mm) of each magnetic scale C1, C2 in the moving direction.

The magnetic scale C1 has both end portions E1L and E1R in the moving direction, and a long scale body AB1 sandwiched between the both end portions E1L and E1R from both sides in the moving direction. A large number of magnetic scales or magnetic patterns are formed on the scale body AB1 at equal intervals along the moving direction. Each of the magnetic sensors S1 to S5 that detect the magnetic scale on the scale body AB1 outputs A-phase and B-phase pulses that are common in a known linear encoder. Typically, the A-phase pulse and the B-phase pulse are 90 degrees out of phase with each other. Note that magnetic scales similar to those of the scale body AB1 may also be formed on both ends E1L and E1R of the magnetic scale C1.

The length of each end E1L, E1R of the magnetic scale C1 in the moving direction is, for example, 8 mm. In this case, the length of the scale body AB1 in the moving direction is 32 mm, which is the length of the magnetic scale C1 of 48 mm minus the total length of both ends E1L and E1R of 16 mm. Thus, in this embodiment, the interval (30 mm) between the magnetic sensors S1 to S5 in the moving direction is smaller than the length (32 mm) of the magnetic scale C1 in the moving direction of the scale body AB1.

A reference mark Z1 as a reference mark is provided on the movable element C1 and/or the magnetic scale C1. Each of the magnetic sensors S1 to S5 that magnetically detected the reference mark Z1 outputs a Z-phase pulse that is common in a known linear encoder. As will be described in detail later, the Z-phase pulse output in response to the reference mark Z1 is used to specify the reference position of the movable element C1. In the illustrated example, the reference mark Z1 is provided at the center of the magnetic scale C1 and/or the scale body AB1 in the moving direction. Each distance (24 mm) between the reference mark Z1 and both ends of the magnetic scale C1 in the moving direction is smaller than the interval (30 mm) between the plurality of magnetic sensors S1 to S5. Further, each distance (16 mm) between the reference mark Z1 and both ends of the scale body AB1 in the moving direction is smaller than the interval (30 mm) between the plurality of magnetic sensors S1 to S5.

The above description of the magnetic scale C1 similarly applies to other magnetic scales such as the magnetic scale C2. However, the dimensions of each of the above parts and the position of the reference mark can be arbitrarily determined for each magnetic scale. In the following, unless otherwise specified, the description of the magnetic scale C1 applies to the magnetic scale C2, etc., and duplicate description of the magnetic scale C2, etc. will be omitted.

Each of the magnetic sensors S1 to S5 includes counting units 51 to 55 that count the A/B phase magnetic scales formed on the scale body AB1 and/or both end portions E1L and E1R of the magnetic scale C1. The direction in which the count value in each of the counting units 51 to 55 increases or decreases corresponds to the moving direction of the magnetic scale C1 (ie, movable element C1) detected by each of the magnetic sensors S1 to S5. For example, when the movable element C1 moves from the left side to the right side in FIG. 2, the count values in each of the counting sections 51 to 55 increase in accordance with the number of A/B phase pulses output by each magnetic sensor S1 to S5. , when the mover C1 moves from the right side to the left side in FIG. 2, the counts in each of the counting units 51 to 55 decrease in accordance with the number of A/B phase pulses output by each of the magnetic sensors S1 to S5.

When the mover C1 moves on the rail, the magnetic sensors S1 to S5 that measure the position of the magnetic scale C1 are sequentially switched. FIG. 3 schematically shows how the positioning subject of the magnetic scale C1 moving from the left side to the right side is switched from the source magnetic sensor S1 to the destination magnetic sensor S2. As illustrated, switching between the magnetic sensors S1 and S2 is performed in a state where the scale body AB1 of the magnetic scale C1 straddles the detection ranges of the two adjacent magnetic sensors S1 and S2. In the illustrated example, when the magnetic sensors S1 and S2 are at positions SW1 and SW2 that are symmetrical with respect to the center of the moving direction of the magnetic scale C1 (the position of the reference mark Z1), the positioning subject of the magnetic scale C1 moves from the magnetic sensor S1 to the magnetic sensor S1. It is switched to sensor S2.

The first switching position SW1 is a position within the scale body AB1 at a predetermined distance from the boundary between the left end E1L and the scale body AB1, and the second switching position SW2 is a position within the scale body AB1 at a predetermined distance from the boundary between the right end E1R and the scale body AB1. This is the position within the main body AB1. In the illustrated example, the distance of the first switching position SW1 from the left end of the scale body AB1 and the distance of the second switching position SW2 from the right end of the scale body AB1 are, for example, 1 mm. In this case, the distance from the center of the scale body AB1 of the first switching position SW1 and the distance of the second switching position SW2 from the center of the scale body AB1 are 15 mm, and the sum (30 mm) is the distance of the magnetic sensors S1 and S2. Matches the interval.

When the positioning main body of the magnetic scale C1 is switched from the magnetic sensor S1 to the magnetic sensor S2, the count value of the counting unit 51 of the magnetic sensor S1 at the source is inherited by the count value of the counting unit 52 of the magnetic sensor S2 at the destination. In the following, when each magnetic sensor S1 to S5 detects the center of magnetic scale C1 (the position of reference mark Z1), the count value of each counter 51 to 55 is zero, and each magnetic sensor S1 to S5 detects the center of magnetic scale C1 (position of reference mark Z1). When detecting the magnetic scale on the side opposite to the moving direction of the mover C1 from the center (left side in FIG. 3), the count value of each counting section 51 to 55 is positive, and each magnetic sensor S1 to S5 is set from the center of the magnetic scale C1. When the magnetic scale is detected on the moving direction side of the movable element C1 (the right side in FIG. 3), the count value of each of the counting sections 51 to 55 is negative.

In the illustrated example, the position of the reference mark Z1 corresponds to the count value "0", the first switching position SW1 corresponds to the count value "+15,000", and the second switching position SW2 corresponds to the count value "-15,000", for example. corresponds to Hereinafter, the count value "+15,000" at the first switching position SW1 will also be referred to as the switching count value, and the count value "-15,000" at the second switching position SW2 will also be referred to as the start count value. In the illustrated example, the switching count value and the starting count value differ only in positive and negative signs. In the illustrated state, when the first switching position SW1 of the magnetic scale C1 is above the magnetic sensor S1, the switching count value "+15,000" of the counting section 51 is set to the counting section 52 of the magnetic sensor S2 at the second switching position SW2. is converted to the starting count value "-15,000". After that, the magnetic sensor S2 becomes the main body for positioning the magnetic scale C1, and its counting unit 52 counts from the starting count value "-15,000" to the next switching count value "+15,000" (to the magnetic sensor S3).

The reference mark detection control unit 40 in FIG. A reference mark detection disabling section 42 is provided that disables the detection of the reference mark Z1 by each of the magnetic sensors S1 to S5 according to the counts in the sections 51 to 55.

Before explaining the control of detection of the reference mark Z1 by the reference mark detection enabling section 41 and/or the reference mark detection disabling section 42, other embodiments are shown in FIGS. 4 and 5. As shown in FIG. 4, when the mover C1 is used for the first time in the linear conveyance system 1, the reference mark Z1 of the magnetic scale C1 is detected by one of the plurality of magnetic sensors (S1, S2 in the example of FIG. 4). Therefore, it is necessary to specify or register the reference position or initial position of the movable element C1. Each magnetic sensor S1, S2 must be able to reliably detect the reference mark Z1 and identify that the reference mark Z1 belongs to the movable element C1. Therefore, in order to prevent false detection of the reference mark Z1 and/or mover C1, each magnetic sensor S1, S2 is in a state in which it cannot detect the reference mark Z1 in principle, so that it can reliably detect the reference mark Z1 and mover C1. The detection of the reference mark Z1 is activated only in this case.

As shown in FIG. 4, it is assumed that the movable element C1, whose initial position is not registered in the linear conveyance system 1, moves along the rail from the left side to the right side of the magnetic sensor S1. The position of the magnetic scale C1 in the state of FIG. 4 is not above any of the magnetic sensors S1 and S2, and is indicated as "S1 left" in FIG. In this "S1 left" state, neither of the magnetic sensors S1 and S2 detects the A/B phase magnetic scale of the magnetic scale C1, so the count values of the respective counters 51 and 52 (Fig. 2) are Both "S1-A/B phase" and "S2-A/B phase" in FIG. 5, which is schematically represented, are "0".

When the mover C1 moves from the state shown in FIG. 4 and at least the right end E1R of the magnetic scale C1 comes over the magnetic sensor S1, the magnetic sensor S1 is formed on the right end E1R and/or the scale body AB1. The magnetic scale of the A/B phase present is detected, and the count value in the counting section 51 increases according to the number of A/B phase pulses from the magnetic sensor S1. In the example of FIG. 5, when the "scale position" of the magnetic scale C1 switches from "S1 left" to "S1 top", "S1-A/B phase" representing the count value of the counting section 51 changes from "1" to " Increases to 12". In this "on S1" state, the magnetic scale C1 is not on the magnetic sensor S2, and the magnetic sensor S2 is not detecting the A/B phase magnetic scale of the magnetic scale C1, so the count value of the counting unit 52 "S2-A/B phase" representing "S2-A/B phase" remains "0". In this example, in order to simplify the explanation, it is assumed that the count value "18" represents the total length of one magnetic scale, but the count value per magnetic scale in the actual linear conveyance system 1 is very large. For example, as described above with reference to FIG. 3, it is about "30,000" ("-15,000" to "+15,000").

The “Z” that appears in the “S1-Z phase” column when the count value of “S1-A/B phase” in Figure 5 reaches “9” indicates that the reference mark Z1 is above the magnetic sensor S1. It means there is. However, as mentioned above, magnetic sensor S1 is basically unable to detect reference mark Z1 ("S1-Z detection" is set to "disabled"), so the count value of "S1-A/B phase" Reference mark Z1 is not detected at the time when becomes "9".

When the count value of "S1-A/B phase" in Figure 5 is between "13" and "18", the magnetic scale C1 is in the "S1 & S2 top" state, which is above both magnetic sensors S1 and S2. There is. Specifically, the portion of the magnetic scale C1 to the left of the reference mark Z1 (the left end E1L or the left portion of the scale body AB1) is above the magnetic sensor S1, and the portion of the magnetic scale C1 to the right of the reference mark Z1 ( The right end portion E1R or the right portion of the scale body AB1) is located above the magnetic sensor S2. In this "S1 & S2 upper" state, since both magnetic sensors S1 and S2 are detecting the A/B phase magnetic scale of the magnetic scale C1, "S1- "A/B phase" and "S2-A/B phase" both increase in the same way.

In this example, "S1-A/B phase" and "S2-A/B phase" continuously increase/decrease by a predetermined count value (in the illustrated example, a count value of "3") in the same direction at approximately the same timing. In this case, detection of the reference mark Z1 by the magnetic sensor in the increasing/decreasing direction, that is, in the moving direction of the movable element C1, is enabled. In the illustrated example, the increase in "13" to "15" of "S1-A/B phase" and the increase in "1" to "3" of "S2-A/B phase" are "3" at almost the same timing. Since the count value is continuously generated, the reference mark Z1 is enabled to be detected by the magnetic sensor S2 in the increasing direction, that is, in the moving direction of the movable element C1 from the left side to the right side (that is, on the right side). In this way, after the count value of "S2-A/B phase" is "4", "S2-Z detection" switches from "impossible" to "possible".

In this state, when the count value of "S2-A/B phase" reaches "9", the reference mark Z1 comes over the magnetic sensor S2 ("Z" appears in the column of "S2-Z phase"), so the corresponding The reference mark Z1 is detected by the magnetic sensor S2, and the initial position of the movable element C1 is registered in the linear conveyance system 1. Note that when the count value of "S2-A/B phase" is "9", the magnetic scale C1 has passed the magnetic sensor S1 to the right, so the "scale position" is such that the magnetic scale C1 is on the magnetic sensor S2 ( It is "on S2" which means that it is on the "S1-A/B phase", and the count value of "S1-A/B phase" remains constant at the maximum value "18".

As described above, in the embodiments shown in FIGS. 4 and 5, only when the count values of two adjacent magnetic sensors S1 and S2 change continuously by a predetermined count value in the same direction at approximately the same timing, the mover Since the detection of the reference mark Z1 by the magnetic sensor S2 on the moving direction side of C1 is enabled, the reference mark Z1 of the mover C1 detected simultaneously by both magnetic sensors S1 and S2 can be reliably detected by the magnetic sensor S2 at the moving destination. can. However, when two movable elements that are close to each other are moving at a constant speed, the count values of two adjacent magnetic sensors that individually detect each movable element are approximately the same timing and the same direction by a predetermined count value. Since a situation of continuous change is realized, there remains a possibility that the reference mark and/or the movable element will be erroneously detected. According to the present embodiment described below, the configuration shown in FIG. The possibility of this can be further reduced.

In FIG. 2, the reference mark detection enabling unit 41 determines that the magnetic scales C1 and C2 correspond to two adjacent magnetic sensors S1/S2, S2/S3, S3/S4, based on the counts in each of the counting units 51 to 55. When moving from the state of straddling the detection range of S4/S5 to outside the detection range of one of the magnetic sensors S1 to S5, the detection of reference marks Z1 and Z2 by the other magnetic sensor S1 to S5 is enabled.

In the simple embodiment shown in FIGS. 6 and 7, the reference mark detection enabling unit 41 determines whether two adjacent magnetic scales C1 If one of the magnetic sensors S1 moves outside the detection range of the magnetic sensor S1 as shown by the broken line from the state of straddling the detection range of the magnetic sensors S1/S2, the other magnetic sensor S2 on the moving direction side of the movable element C1 Detection of reference mark Z1 is enabled.

As shown in FIG. 7, the reference mark detection enabling unit 41 changes the count values of the counting units 51 and 52 in two adjacent magnetic sensors S1 and S2 in the same manner as in FIG. In the example, if the count value of magnetic sensor S2 is increasing from "1" to "3" while the count value of magnetic sensor S1 is increasing from "13" to "15", the magnetic It is determined that the scale C1 is in a state of "above S1 & S2", which straddles two adjacent detection ranges. The magnetic scale C1 in this "on S1 & S2" state is on both the magnetic sensors S1 and S2, as shown by the solid line in FIG. The reference mark Z1 at this time is located between the detection ranges of the two adjacent magnetic sensors S1 and S2.

As shown in FIG. 7, in the state "on S1 & S2" where the magnetic scale C1 straddles two adjacent detection ranges, the count value of magnetic sensor S1 is "18" and the count value of magnetic sensor S2 is "18". This continues until the count value of the magnetic sensor S1 reaches "6", and when only the count value of the magnetic sensor S2 increases to "7" while the count value of the magnetic sensor S1 remains "18", the mover C1 moves as shown by the broken line in FIG. It moves out of the detection range of one of the magnetic sensors S1 on the opposite side to the moving direction and enters the state "on S2". Therefore, the reference mark detection enabling unit 41 enables the detection of the reference mark Z1 by the other magnetic sensor S2 on the moving direction side of the movable element C1 at the timing when the count value of only the magnetic sensor S2 increases to "7". do. Note that the reference mark detection enabling unit 41 detects the reference mark by the other magnetic sensor S2 on the moving direction side of the movable element C1 at the timing when the magnetic sensor S1 cannot detect the A/B phase magnetic scale of the magnetic scale C1. The detection of Z1 may be enabled.

At this point, the reference mark Z1 is still located between the detection ranges of the two adjacent magnetic sensors S1 and S2, as shown by the broken line in FIG. Reference mark Z1 is placed above magnetic sensor S2. Specifically, when the count value of the magnetic sensor S2 reaches "9", the reference mark Z1 comes above the magnetic sensor S2 ("Z" appears in the "S2-Z phase" column), so the magnetic sensor S2 The reference mark Z1 is detected and the initial position of the movable element C1 is registered in the linear conveyance system 1. The reference mark detection disabling unit 42 in FIG. When Z1 is detected, the detection of the reference mark Z1 by the other magnetic sensor S2 is disabled after the S2 count value is "10" ("S2-Z detection" is set to "disabled").

Next, a case where a plurality of movers exist will be explained. In this case, two movers (i.e., magnetic scales) that are close to each other may enter the detection range of one magnetic sensor at the same time, so it is necessary to prevent false detection of each magnetic scale as shown in Figure 8. It is preferable to take measures for this in advance.

FIG. 8 schematically shows a state in which two magnetic scales C1 and C2 that have approached to the minimum approachable distance are simultaneously within the detection range R of one magnetic sensor S1 to S5. In this example, the minimum approachable distance between the two magnetic scales C1 and C2 (the distance between the right end of the magnetic scale C1 and the left end of the magnetic scale C2 in the illustrated state) is 2 mm, and the detection range R of the magnetic sensors S1 to S5 is The length in the orbital direction (left-right direction in FIG. 8) is 5 mm. As described above, A/B phase magnetic scales are formed on the right end E1R of the magnetic scale C1 and the left end E2L of the magnetic scale C2, similarly to the scale body AB1 of the magnetic scale C1 and the scale body AB2 of the magnetic scale C2. Therefore, in the illustrated state, the magnetic sensors S1 to S5 simultaneously detect the A/B phase magnetic scale at the right end E1R and the A/B phase magnetic scale at the left end E2L. In this case, the magnetic sensors S1 to S5 cannot distinguish and detect the two magnetic scales C1 and C2.

In order to prevent false detection of the two magnetic scales C1 and C2 that are close to each other in this way, the right end E1R of the magnetic scale C1 and/or the left end E2L of the magnetic scale C2 are shielded from the detection range R of the magnetic sensors S1 to S5. A shielding member B1R and/or a shielding member B2L are provided.

The shielding member B1R shields at least the A/B phase magnetic scale provided on the right end side far from the scale body AB1 in the right end E1R of the magnetic scale C1. Specifically, as described above, the right end portion of the right end portion E1R having a total length of 8 mm is shielded by the shielding member B1R. If the length of the shielding member B1R in the orbital direction is greater than or equal to the length (5 mm) of the detection range R of the magnetic sensors S1 to S5 in the orbital direction, the shielding member B1R alone can shield the detection range R of the magnetic sensors S1 to S5. Thus, it is possible to prevent the magnetic scale C1 from being detected simultaneously with the magnetic scale C2. Also, the length of the shielding member B1R in the orbital direction is the length of the detection range R of the magnetic sensors S1 to S5 in the orbital direction (5 mm) minus the minimum approachable distance (2 mm) of the movers C1 and C2. (3 mm) or more, the shielding member B1R alone can substantially shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic scale C1 from being detected simultaneously with the magnetic scale C2. Furthermore, the length of the shielding member B1R in the orbital direction is the length of the detection range R of the magnetic sensors S1 to S5 in the orbital direction (5 mm) minus the minimum approachable distance of the movers C1 and C2 (2 mm). (3 mm) or more than half (1.5 mm), the detection range R of the magnetic sensors S1 to S5 is substantially shielded together with the shielding member B2L of the same length, so that the magnetic scale C1 can detect the magnetic scale C2 at the same time. You can prevent this from happening.

The shielding member B2L shields at least the A/B phase magnetic scale provided on the left end side far from the scale body AB2 at the left end E2L of the magnetic scale C2. Specifically, as described above, the left end portion of the left end portion E2L having a total length of 8 mm is shielded by the shielding member B2L. If the length of the shielding member B2L in the orbital direction is greater than or equal to the length (5 mm) of the detection range R of the magnetic sensors S1 to S5 in the orbital direction, the shielding member B2L alone can shield the detection range R of the magnetic sensors S1 to S5. Thus, it is possible to prevent the magnetic scale C2 from being detected simultaneously with the magnetic scale C1. Also, the length of the shielding member B2L in the orbital direction is the length of the detection range R of the magnetic sensors S1 to S5 in the orbital direction (5 mm) minus the minimum approachable distance (2 mm) of the movers C1 and C2. (3 mm) or more, the shielding member B2L alone can substantially shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic scale C2 from being detected simultaneously with the magnetic scale C1. Furthermore, the length of the shielding member B2L in the orbital direction is the length of the detection range R of the magnetic sensors S1 to S5 in the orbital direction (5 mm) minus the minimum approachable distance of the movers C1 and C2 (2 mm). If it is more than half (1.5 mm) of (3 mm), the detection range R of the magnetic sensors S1 to S5 will be substantially shielded together with the shielding member B1R of the same length, and the magnetic scale C2 will be detected at the same time as the magnetic scale C1. You can prevent this from happening.

In the magnetic scale C1, a shielding member similar to the shielding member B1R at the right end (or the shielding member B2L at the left end of the magnetic scale C2) may be provided at the left end (not shown), or a shielding member may be provided only at the left end. may be provided. Similarly, in the magnetic scale C2, a shielding member similar to the shielding member B2L at the left end (or the shielding member B1R at the right end of the magnetic scale C1) may be provided at the right end (not shown), or only at the right end. A shielding member may be provided.

The shielding member B1R and/or the shielding member B2L are formed of a ferromagnetic material that magnetically shields at least one end of the magnetic scale C1 and/or the magnetic scale C2 from the magnetic sensors S1 to S5. Examples of the ferromagnetic material include metals and alloys such as iron, cobalt, nickel, gadolinium, and manganese. Note that when an optical scale is used instead of a magnetic scale as the positioning scale, the shielding member may be formed of a light-shielding material that optically shields the optical sensor as the position detection section. As described above, by taking the measures shown in Fig. 8, even if the ends of the positioning scales of two movers that are close to each other enter the detection range of one position detector at the same time, the ends The shielding member provided on at least one of the two positioning scales can prevent the two positioning scales from being erroneously detected at the same time by the position detecting section.

Next, in the embodiments of FIGS. 4 and 5 (embodiments that do not use the reference mark detection enabling section 41 and/or the reference mark detection disabling section 42), there is a possibility that the reference mark and/or the mover may be erroneously detected. A plurality of embodiments in which two movable elements that are close to each other and move at a constant speed will be described.

In the first embodiment shown in FIGS. 9 and 10, in the initial state shown in FIG. 9 (a state in which the movers C1 and C2 whose initial positions are unregistered start moving rightward), the mover C1 is above both magnetic sensors S2 and S3, and mover C2 is above magnetic sensor S4. As shown in FIG. 10, the reference mark detection enabling unit 41 determines whether the magnetic scale C1 straddles the detection range of two adjacent magnetic sensors S2/S3 based on the counts in the counting units 52 and 53. When the reference mark Z1 is moved out of the detection range of one of the magnetic sensors S2 from the state in which the movable element C1 is moved, the detection of the reference mark Z1 by the other magnetic sensor S3 on the moving direction side of the movable element C1 is enabled.

When the movable element C1 further moves in the same direction in this state, the reference mark Z1 comes above the magnetic sensor S3, so the reference mark Z1 is detected by the magnetic sensor S3 and the initial position of the movable element C1 is set to the linear conveyance system 1. will be registered. The reference mark detection disabling unit 42 disables the detection of the reference mark Z1 by the magnetic sensor S3 after the reference mark Z1 is detected by the magnetic sensor S3. Note that after this, a situation occurs in which the magnetic scale C1 moves from being across the detection ranges of two adjacent magnetic sensors S3/S4 to outside the detection range of one of the magnetic sensors S3. Since the reference mark Z1 has already been detected by the magnetic sensor S3, the detection of the reference mark Z1 by the magnetic sensor S4 is not enabled.

On the other hand, the reference mark detection enabling unit 41 detects the magnetic scale C2 from the state in which the magnetic scale C2 straddles the detection range of two adjacent magnetic sensors S4/S5 based on the count values in the counting units 54 and 55. When moving outside the detection range of the sensor S4, detection of the reference mark Z2 by the other magnetic sensor S5 on the moving direction side of the movable element C2 is enabled. When the mover C2 further moves in the same direction in this state, the reference mark Z2 comes above the magnetic sensor S5, so the reference mark Z2 is detected by the magnetic sensor S5 and the initial position of the mover C2 is set to the linear conveyance system 1. will be registered. The reference mark detection disabling unit 42 disables the detection of the reference mark Z2 by the magnetic sensor S5 after the reference mark Z2 is detected by the magnetic sensor S5. As described above, even when the two movable elements C1 and C2 that are close to each other are moving at the same speed, the reference marks Z1 and Z2 of each of the movable elements C1 and C2 can be reliably detected.

In the second embodiment shown in FIGS. 11 and 12, in the initial state shown in FIG. 11, the mover C1 is above the magnetic sensor S2, and the mover C2 is above both the magnetic sensors S3 and S4. be. As shown in FIG. 12, the reference mark detection enabling unit 41 determines whether the magnetic scale C2 straddles the detection range of two adjacent magnetic sensors S3/S4 based on the counts in the counting units 53 and 54. When the movable element C2 moves out of the detection range of one of the magnetic sensors S3, the detection of the reference mark Z2 by the other magnetic sensor S4 on the moving direction side of the movable element C2 is enabled.

When the mover C2 further moves in the same direction in this state, the reference mark Z2 comes above the magnetic sensor S4, so the reference mark Z2 is detected by the magnetic sensor S4 and the initial position of the mover C2 is set to the linear conveyance system 1. will be registered. The reference mark detection disabling unit 42 disables the detection of the reference mark Z2 by the magnetic sensor S4 after the reference mark Z2 is detected by the magnetic sensor S4. Note that after this, a situation occurs in which the magnetic scale C2 moves from being across the detection ranges of two adjacent magnetic sensors S4/S5 to outside the detection range of one of the magnetic sensors S4. Since the reference mark Z2 has already been detected by the magnetic sensor S4, the detection of the reference mark Z2 by the magnetic sensor S5 is not enabled.

On the other hand, the reference mark detection enabling unit 41 detects the magnetic scale C1 from the state in which the magnetic scale C1 straddles the detection range of two adjacent magnetic sensors S2/S3 based on the count values in the counting units 52 and 53. When moving outside the detection range of the sensor S2, detection of the reference mark Z1 by the other magnetic sensor S3 on the moving direction side of the movable element C1 is enabled. When the movable element C1 further moves in the same direction in this state, the reference mark Z1 comes above the magnetic sensor S3, so the reference mark Z1 is detected by the magnetic sensor S3 and the initial position of the movable element C1 is set to the linear conveyance system 1. will be registered. The reference mark detection disabling unit 42 disables the detection of the reference mark Z1 by the magnetic sensor S3 after the reference mark Z1 is detected by the magnetic sensor S3. As described above, even when the two movable elements C1 and C2 that are close to each other are moving at the same speed, the reference marks Z1 and Z2 of each of the movable elements C1 and C2 can be reliably detected.

In the third embodiment shown in FIGS. 13 and 14, in the initial state shown in FIG. 13, the mover C1 is above both the magnetic sensors S1 and S2, and the mover C2 is above the magnetic sensors S3 and S4. It's on top of both. As shown in FIG. 14, the reference mark detection enabling unit 41 determines whether the magnetic scale C1 straddles the detection range of two adjacent magnetic sensors S1/S2 based on the counts in the counting units 51 and 52. When the movable element C1 moves out of the detection range of one of the magnetic sensors S1, the detection of the reference mark Z1 by the other magnetic sensor S2 on the moving direction side of the movable element C1 is enabled.

When the mover C1 further moves in the same direction in this state, the reference mark Z1 comes above the magnetic sensor S2, so the reference mark Z1 is detected by the magnetic sensor S2 and the initial position of the mover C1 is set to the linear conveyance system 1. will be registered. The reference mark detection disabling unit 42 disables the detection of the reference mark Z1 by the magnetic sensor S2 after the reference mark Z1 is detected by the magnetic sensor S2. After this, a situation occurs in which the magnetic scale C1 moves from the detection range of two adjacent magnetic sensors S2/S3 to outside the detection range of one of the magnetic sensors S2. Since the reference mark Z1 has already been detected by the magnetic sensor S2, the detection of the reference mark Z1 by the magnetic sensor S3 is not enabled.

On the other hand, the reference mark detection enabling unit 41 detects the magnetic scale C2 from the state in which the magnetic scale C2 straddles the detection range of two adjacent magnetic sensors S3/S4 based on the count values in the counting units 53 and 54. When moving outside the detection range of the sensor S3, detection of the reference mark Z2 by the other magnetic sensor S4 on the moving direction side of the movable element C2 is enabled.

When the mover C2 further moves in the same direction in this state, the reference mark Z2 comes above the magnetic sensor S4, so the reference mark Z2 is detected by the magnetic sensor S4 and the initial position of the mover C2 is set to the linear conveyance system 1. will be registered. The reference mark detection disabling unit 42 disables the detection of the reference mark Z2 by the magnetic sensor S4 after the reference mark Z2 is detected by the magnetic sensor S4. Although not shown in the drawings, a situation subsequently occurs in which the magnetic scale C2 moves from a state where it straddles the detection ranges of two adjacent magnetic sensors S4/S5 to outside the detection range of one of the magnetic sensors S4. However, since the reference mark Z2 of the magnetic scale C2 has already been detected by the magnetic sensor S4, the detection of the reference mark Z2 by the magnetic sensor S5 is not enabled. As described above, even when the two movable elements C1 and C2 that are close to each other are moving at the same speed, the reference marks Z1 and Z2 of each of the movable elements C1 and C2 can be reliably detected.

In the first to third embodiments described above, the moving direction of each movable element C1, C2 is constant, but even if the moving direction of each movable element C1, C2 changes, the reference mark of each movable element C1, C2 Z1 and Z2 can be detected reliably. For example, after the other (for example, right side) magnetic sensor is activated by the reference mark detection activation unit 41, and before the other magnetic sensor detects the reference marks Z1 and Z2, the magnetic scales C1 and C2 are activated on one side ( For example, when the reference mark detection enabling unit 41 returns to the state where it straddles the detection range of the magnetic sensor on the left side and the other magnetic sensor, and further moves out of the detection range of the other magnetic sensor, the reference mark detection enabling unit 41 Detection of reference marks Z1 and Z2 is enabled.

At this time, after the other magnetic sensor is enabled by the reference mark detection enabling unit 41, the reference mark detection disabling unit 42 disables the magnetic scale from the reference mark Z1 and before the other magnetic sensor detects the reference marks Z1 and Z2. When C1 and C2 return to the state where they straddle the detection range of one magnetic sensor and the other magnetic sensor, and further move outside the detection range of the other magnetic sensor, the reference mark Z1 by the other magnetic sensor, The detection of Z2 may be disabled. Alternatively, after the other magnetic sensor is enabled by the reference mark detection enabling unit 41, the reference mark detection disabling unit 42 disables the magnetic scale C1 before the other magnetic sensor detects the reference marks Z1 and Z2. , C2 returns to the state where it straddles the detection range of one magnetic sensor and the other magnetic sensor, the detection of reference marks Z1 and Z2 by the other magnetic sensor may be disabled.

The present invention has been described above based on the embodiments. Those skilled in the art will understand that the embodiments are merely illustrative, and that various modifications can be made to the combinations of the constituent elements and processing processes, and that such modifications are also within the scope of the present invention.

In the embodiment, a linear conveyance system is illustrated in which the mover is driven based on the magnetic force between the permanent magnet provided in the mover and the electromagnet provided in the stator. It can be applied to any drive device based on

Note that the functional configuration of each device described in the embodiments can be realized by hardware resources, software resources, or cooperation between hardware resources and software resources. A processor, ROM, RAM, and other LSIs can be used as hardware resources. Programs such as operating systems and applications can be used as software resources.

1 linear conveyance system, 2 stator, 3 movable element, 4 positioning device, 40 reference mark detection control section, 41 reference mark detection enabling section, 42 reference mark detection disabling section, 51 counting section, AB1 scale body, B1R shielding Components, C1 magnetic scale, S1 magnetic sensor, Z1 reference mark.

Claims (11)

A plurality of position detection units arranged along the moving direction of the movable element in order to position a positioning scale attached to the movable element, the intervals between which are smaller than the length of the positioning scale in the moving direction, and the movable a plurality of position detection units that identify the reference position of the movable element by detecting reference marks provided on the movable element;
When the positioning scale moves from a state where it straddles the detection ranges of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark by the other position detection unit is enabled. a reference mark detection enabling section for
A positioning device comprising: a reference mark detection disabling section that disables detection of the reference mark by the other position detecting section when the other position detecting section enabled by the reference mark detection enabling section detects the reference mark; The positioning device according to claim 1, further comprising: After the other position detecting section is enabled by the reference mark detection enabling section and before the other position detecting section detects the reference mark, the positioning scale is activated to detect the one position detecting section and the other position detecting section. criteria for disabling the detection of the reference mark by the other position detection unit when the position returns to a state where the position detection unit straddles the detection range of the position detection unit and further moves outside the detection range of the other position detection unit; The positioning device according to claim 1 or 2, further comprising a mark detection invalidation section. After the other position detecting section is enabled by the reference mark detection enabling section and before the other position detecting section detects the reference mark, the positioning scale is activated to detect the one position detecting section and the other position detecting section. Claim 1 or 2, further comprising a reference mark detection disabling unit that disables detection of the reference mark by the other position detecting unit when the reference mark returns to a state where the reference mark straddles the detection range of the other position detecting unit. The positioning device described in . After the other position detecting section is enabled by the reference mark detection enabling section and before the other position detecting section detects the reference mark, the positioning scale is activated to detect the one position detecting section and the other position detecting section. When the reference mark detection enabler returns to the state where it straddles the detection range of the one position detector and further moves out of the detection range of the other position detector, the reference mark detection enabler detects the reference mark detected by the one position detector. The positioning device according to any one of claims 1 to 4, which enables mark detection. The positioning scale includes a plurality of scales provided along the movement direction,
The position detection unit includes a counting unit that counts each of the detected scales,
The reference mark detection enabling unit is configured to enable the positioning scale to straddle two adjacent detection ranges when the count values of the counting units in two adjacent position detection units are changing in the same manner. It is determined that the state is
The positioning device according to any one of claims 1 to 5. Any one of claims 1 to 6, wherein the reference mark is located at a position sandwiched between two detection ranges when the positioning scale straddles the detection ranges of two adjacent position detection units. The positioning device described in . 8. The positioning device according to claim 1, wherein each distance between the reference mark and both ends of the positioning scale in the moving direction is smaller than an interval between the plurality of position detection units. a plurality of movers driven along a trajectory;
a plurality of position detection units disposed along the trajectory for positioning a positioning scale attached to each movable element, the intervals between which are smaller than the length of the positioning scale in the orbital direction; a plurality of position detection units that identify the reference position of each movable element by detecting provided reference marks;
When the positioning scale moves from a state where it straddles the detection ranges of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark by the other position detection unit is enabled. a reference mark detection enabling section for
A drive device comprising: A plurality of position detection units arranged along the moving direction of the movable element in order to position a positioning scale attached to the movable element, the intervals between which are smaller than the length of the positioning scale in the moving direction, and the movable In a positioning device including a plurality of position detection units that identify the reference position of the movable element by detecting a reference mark provided on the movable element,
When the positioning scale moves from a state where it straddles the detection ranges of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark by the other position detection unit is enabled. A positioning method comprising a fiducial mark detection enabling step. A plurality of position detection units arranged along the moving direction of the movable element in order to position a positioning scale attached to the movable element, the intervals between which are smaller than the length of the positioning scale in the moving direction, and the movable In a positioning device including a plurality of position detection units that identify the reference position of the movable element by detecting a reference mark provided on the movable element,
When the positioning scale moves from a state where it straddles the detection ranges of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark by the other position detection unit is enabled. A positioning program that causes a computer to execute a fiducial mark detection enabling step.

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