Positioning device, driving device, positioning method and storage medium

Abstract

The present invention provides a positioning device capable of reliably detecting reference marks set on a movable member. The positioning device (4) includes: a plurality of magnetic sensors (S1 to S5) arranged along the moving direction of the movable member for measuring the position of magnetic rulers (C1, C2) mounted on the movable member, and the interval between them is less than the length in the moving direction of the magnetic rulers (C1, C2), and they detect reference marks (Z1, Z2) set on the movable member to determine the reference position of the movable member; and a reference mark detection activating unit (41) that, when the magnetic rulers (C1, C2) move from a state spanning the detection range of two adjacent magnetic sensors (S1 and S2, S2 and S3, S3 and S4, S4 and S5) to outside the detection range of one of the magnetic sensors, makes the detection of the reference marks (Z1, Z2) of the other magnetic sensor effective.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2022-032725, filed on March 3, 2022. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] This invention relates to a drive device for moving a movable part along a track, etc. Background Technology

[0003] Patent Document 1 discloses a linear conveying system as a drive device for moving a movable member along a track. Multiple magnetic sensors arranged along the track measure the position of a magnetic scale (i.e., the movable member) mounted on it. The magnetic sensors detect a reference mark set on the movable member, thereby determining the reference position of the movable member.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-164396

[0005] In the linear conveying system of Patent Document 1, the spacing between multiple magnetic sensors is less than the length of the magnetic ruler in the track direction. Therefore, a single magnetic ruler (i.e., a movable element) may sometimes traverse the detection range of two adjacent magnetic sensors. Furthermore, in the presence of multiple movable elements, two different magnetic rulers (i.e., movable elements) may simultaneously enter the detection range of two adjacent magnetic sensors. Even under such complex conditions, the magnetic sensors must be able to reliably detect each reference mark and identify the movable element on which each reference mark is located. Summary of the Invention

[0006] The present invention was made in view of the following situation, and its object is to provide a positioning device, etc., that can reliably detect reference marks set on movable parts.

[0007] To solve the above problems, a positioning device according to one embodiment of the present invention includes: a plurality of position detection units, which are arranged along the moving direction of the movable member for measuring a positioning scale mounted on the movable member, and the interval between them is less than the length of the positioning scale in the moving direction, and which detect a reference mark set on the movable member to determine the reference position of the movable member; and a reference mark detection activating unit, which activates the detection of the reference mark of the other position detection unit when the positioning scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units.

[0008] In this embodiment, when the positioning scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark of the other position detection unit becomes effective. For example, in the presence of multiple movable members (i.e., positioning scales), even if two different positioning scales simultaneously enter the detection range of two adjacent position detection units, the detection of the reference mark is not effective in this state, thus preventing false detection of the reference mark.

[0009] Another embodiment of the present invention is a driving device. This device includes: a plurality of movable members driven along a track; a plurality of position detection units arranged along the track for measuring the position of a measuring scale mounted on each movable member, wherein the interval between them is less than the length of the measuring scale in the track direction, and each unit detects a reference mark provided on each movable member to determine the reference position of each movable member; and a reference mark detection activating unit that activates the detection of a reference mark of another position detection unit when the measuring scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units.

[0010] Another embodiment of the present invention is a positioning method. This method is applied to a positioning device having multiple position detection units. These multiple position detection units are arranged along the movement direction of the movable member for positioning a positioning scale mounted on a movable member, and the interval between them is less than the length of the positioning scale in the movement direction. They detect a reference mark set on the movable member to determine the reference position of the movable member. The method includes a reference mark detection activating step, which is as follows: when the positioning scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark of the other position detection unit becomes valid.

[0011] Furthermore, any combination of the above-mentioned constituent elements or the manner in which these elements are transformed in methods, apparatus, systems, recording media, computer programs, etc., are also included in this invention.

[0012] According to the present invention, a reference mark set on a movable part can be reliably detected. Attached Figure Description

[0013] Figure 1 It is a three-dimensional diagram showing the overall structure of a linear conveying system.

[0014] Figure 2 This schematically illustrates a positioning device in a linear conveying system, consisting of a position detection unit and a positioning scale.

[0015] Figure 3This schematically illustrates the situation where the measuring body of a moving magnetic ruler switches from the magnetic sensor of the moving source to the magnetic sensor of the moving destination.

[0016] Figure 4 This describes an embodiment that does not utilize reference markers to detect the effective part and / or the invalid part.

[0017] Figure 5 This describes an embodiment that does not utilize reference markers to detect the effective part and / or the invalid part.

[0018] Figure 6 This illustrates an embodiment that utilizes reference markers to detect valid parts and / or reference markers to detect invalid parts.

[0019] Figure 7 This illustrates an embodiment that utilizes reference markers to detect valid parts and / or reference markers to detect invalid parts.

[0020] Figure 8 This schematically represents the state where two magnetic rulers, brought to their minimum approach distance, simultaneously enter the detection range of a magnetic sensor.

[0021] Figure 9 The first embodiment shows multiple movable parts moving at the same speed.

[0022] Figure 10 The first embodiment shows multiple movable parts moving at the same speed.

[0023] Figure 11 The second embodiment shows multiple movable parts moving at the same speed.

[0024] Figure 12 The second embodiment shows multiple movable parts moving at the same speed.

[0025] Figure 13 The third embodiment represents multiple movable parts moving at the same speed.

[0026] Figure 14 The third embodiment represents multiple movable parts moving at the same speed.

[0027] In the diagram: 1-Linear conveying system, 2-Fixed component, 3-Moving component, 4-Positioning device, 40-Reference mark detection and control unit, 41-Reference mark detection and activation unit, 42-Reference mark detection and invalidation unit, 51-Counting unit, AB1-Scale body, B1R-Shielding component, C1-Magnetic scale, S1-Magnetic sensor, Z1-Reference mark. Detailed Implementation

[0028] Hereinafter, embodiments for carrying out the present invention (hereinafter also referred to as embodiments) will be described in detail with reference to the accompanying drawings. In the following description and / or drawings, the same or equivalent constituent elements, components, and processes are labeled with the same symbols, and repeated descriptions are omitted. In the drawings, scales and shapes of various parts are appropriately provided for the purpose of simplification, and are not intended to be limiting unless otherwise specified. The embodiments are merely illustrative and are not intended to limit the scope of the present invention. All features or combinations thereof described in the embodiments are not necessarily essential to the present invention.

[0029] Figure 1 This is a perspective view showing the overall structure of one embodiment of the driving device according to the present invention (i.e., linear conveying system 1). The linear conveying system 1 includes a fixed member 2 forming a ring-shaped guide rail or track, and multiple movable members 3A, 3B, 3C, and 3D (hereinafter collectively referred to as movable members 3) driven by the fixed member 2 to move along the guide rail. A linear motor is formed along the ring-shaped guide rail by positioning an electromagnet or coil mounted on the fixed member 2 opposite to a permanent magnet mounted on the movable members 3. Furthermore, the guide rail formed by the fixed member 2 is not limited to a ring shape and can be of any shape. For example, the guide rail can be straight or curved, and one guide rail can branch into multiple guide rails, or multiple guide rails can be combined into one guide rail. Moreover, the orientation of the guide rail formed by the fixed member 2 is also arbitrary. Figure 1 In the example, the guide rail is arranged in the horizontal plane, but it can also be arranged in the vertical plane, or in a plane or curved surface with any angle of inclination.

[0030] The fastener 2 has a guide surface 21 with the horizontal direction as its normal direction. The guide surface 21 extends in a strip shape along the forming direction of the guide rail, such as... Figure 1 As shown in the example, when the guide rail is formed in a ring shape, the guide rail surface 21 becomes a (hypothetical) annular strip formed by connecting the two ends together. On the guide rail surface 21, which can form a guide rail of any shape, multiple drive modules (not shown) equipped with electromagnets are continuously or periodically embedded or arranged along the guide rail. The electromagnets in the drive modules generate a magnetic field, which exerts a pushing force along the guide rail on the permanent magnet of the movable member 3 and / or the electromagnet itself. Specifically, if a drive current such as three-phase alternating current flows through these multiple electromagnets, a moving magnetic field is generated that drives the movable member 3 equipped with a permanent magnet in a linear direction along the guide rail in the desired tangential direction. Furthermore, in Figure 1 In the example, the normal direction of the guide rail surface 21 that forms an annular guide rail in the horizontal plane is horizontal. However, the normal direction of the guide rail surface 21 can also be vertical or any other arbitrary direction.

[0031] On the measuring part 22 of the fixing member 2, which is provided on the upper or lower surface perpendicular to the guide rail surface 21, magnetic sensors as multiple position detection parts are continuously or periodically embedded. Figure 1 (Not shown in the image), this magnetic sensor is capable of measuring the magnetic scale mounted on the movable part 3 as a measuring object or measuring scale. Figure 1 (Not shown in the image). Magnetic sensors that measure the position of a magnetic ruler formed by a magnetic stripe pattern or magnetic scale with a constant spacing typically have multiple magnetic detection heads. By offsetting the intervals of the multiple magnetic detection heads relative to the spacing or period of the magnetic pattern on the magnetic ruler, the magnetic sensor can accurately determine the position of the magnetic ruler. In a typical magnetic sensor with two magnetic detection heads, for example, the interval between the two magnetic detection heads is offset by 1 / 4 of a spacing (90 degrees phase offset) relative to the magnetic pattern on the magnetic ruler. Alternatively, the magnetic sensor can be provided on the movable member 3 and the magnetic ruler on the fixed member 2, in the opposite manner described above. Furthermore, by differentiating the position of the movable member 3 measured by the positioning unit 22 with time, the velocity of the movable member 3 can be detected; and by differentiating this velocity with time, the acceleration of the movable member 3 can be detected.

[0032] The position detection unit mounted on the fixed member 2 and the measuring object or measuring scale mounted on the movable member 3 are not limited to the magnetic type described above; optical or other types can also be used. In the case of the optical type, an optical scale formed by patterns or graduations with constant spacing is mounted on the movable member 3, and an optical sensor capable of reading the patterns of the optical scale is provided on the fixed member 2. In both magnetic and optical types, since the position detection unit measures the measuring object (magnetic scale or optical scale) in a non-contact manner, the risk of position detection unit failure, such as when the transported object conveyed by the movable member 3 scatters and enters the measuring area (the upper surface of the fixed member 2), can be reduced. However, in the optical type, if the transported object, such as liquid or powder, enters the measuring area and covers the optical scale, the measuring accuracy will deteriorate. Therefore, it is preferable to use a magnetic type, where the measuring accuracy will not deteriorate even if the transported object, whose magnetism is negligible, enters the measuring area.

[0033] The movable member 3 includes: a movable member body 31, which faces the guide rail surface 21 of the fixed member 2; a measured position part 32, which extends horizontally from the upper part of the movable member body 31 and faces the measuring position part 22 of the fixed member 2; and a conveying part 33, which extends horizontally from the movable member body 31 toward the side opposite to the measured position part 32 (the side away from the fixed member 2) and is used to carry or fix the transported object. The movable member body 31 includes one or more permanent magnets (not shown) facing a plurality of electromagnets embedded along the guide rail surface 21 of the fixed member 2. Because the moving magnetic field generated by the electromagnets of the fixed member 2 applies a linear force or propulsive force in the tangential direction of the guide rail to the permanent magnets and / or the electromagnets themselves of the movable member 3, the movable member 3 drives linearly along the guide rail surface 21 relative to the fixed member 2.

[0034] On the measured position part 32 of the movable member 3, a magnetic scale or optical scale, serving as the measuring object or measuring ruler, is arranged opposite to a position detection unit (magnetic sensor or optical sensor) provided on the measuring position part 22 of the fixed member 2. The position detection unit is located on the upper surface of the fixed member 2. Figure 1 In the example, the measuring object, such as a magnetic ruler, is mounted on the lower surface of the measuring part 32 of the movable member 3. When the measuring part 22 and the measuring part 32 are magnetic, in order to prevent the magnetic field between the electromagnet of the guide rail surface 21 and the permanent magnet of the movable member body 31 from affecting the magnetic measurement of the measuring part 22 and the measuring part 32, it is preferable to form the guide rail surface 21 and the measuring part 22 on different surfaces or at locations far apart from each other in the fixing member 2, and to form the movable member body 31 and the measuring part 32 on different surfaces or at locations far apart from each other in the movable member 3.

[0035] Figure 1 The illustration shows four movable elements 3A, 3B, 3C, and 3D. However, in a linear conveyor system 1 that transports a large number of small quantities of items, it is conceivable that more than 1,000 movable elements 3 may be required. In this case, it is common for two different positioning scales (i.e., movable elements 3) to simultaneously enter the detection range of two adjacent position detection units. Furthermore, it is also possible for two movable elements 3 (i.e., positioning scales) that are close to each other to simultaneously enter the detection range of a single position detection unit. Even in such complex situations, each position detection unit must reliably detect the reference marks of the movable elements 3 described below and be able to uniquely identify the movable element 3 on which each reference mark is provided.

[0036] Figure 2The diagram schematically illustrates a positioning device 4 in a linear conveying system 1, comprising a position detection unit and a positioning scale. The positioning device 4 includes multiple (five in the illustrated example) magnetic sensors S1 to S5 serving as position detection units. These magnetic sensors S1 to S5 measure the position of a magnetic scale (hereinafter referred to as magnetic scale C1 and C2) mounted on multiple (two in the illustrated example) movable members C1 and C2, along the track direction of the fixed member 2 or the movement direction of the movable members C1 and C2. Figure 2 (In the left and right directions) it is embedded or configured on the guide rail surface 21.

[0037] The intervals in the moving directions of the magnetic sensors S1 to S5 may differ from one another, but in this embodiment, examples with equal intervals will be described. In this case, the intervals in the moving directions of the magnetic sensors S1 to S5 are, for example, 30 mm. Furthermore, the lengths in the moving directions of the magnetic scales C1 and C2 may also differ from one another, but in this embodiment, examples with equal lengths will be described. In this case, the lengths in the moving directions of the magnetic scales C1 and C2 are, for example, 48 mm. Thus, in this embodiment, the interval (30 mm) in the moving directions of the magnetic sensors S1 to S5 is less than the length (48 mm) in the moving directions of the magnetic scales C1 and C2.

[0038] The magnetic scale C1 has two ends E1L and E1R in the direction of movement, and a long strip of scale body AB1 sandwiched between the two ends E1L and E1R from both sides in the direction of movement. Multiple magnetic graduations or magnetic patterns are formed on the scale body AB1 at equal intervals along the direction of movement. In known linear encoders, each magnetic sensor S1 to S5 that detects the magnetic graduations of the scale body AB1 outputs general A-phase and B-phase pulses. Typically, the A-phase pulse and the B-phase pulse are 90 degrees out of phase. Furthermore, the same magnetic graduations as the scale body AB1 can also be formed at the two ends E1L and E1R of the magnetic scale C1.

[0039] The length of each end E1L and E1R of the magnetic scale C1 in the direction of movement is, for example, 8 mm. The length of the scale body AB1 in the direction of movement is 32 mm, obtained by subtracting the total length of the two ends E1L and E1R (16 mm) from the length of the magnetic scale C1 (48 mm). Thus, in this embodiment, the interval (30 mm) between the magnetic sensors S1 to S5 in the direction of movement is less than the length (32 mm) of the scale body AB1 of the magnetic scale C1 in the direction of movement.

[0040] A reference mark Z1, serving as a reference marker, is provided on the movable member C1 and / or the magnetic scale C1. In a known linear encoder, each magnetic sensor S1 to S5 that magnetically detects the reference mark Z1 outputs a general Z-phase pulse. Details will be described later, but the Z-phase pulse output corresponding to the reference mark Z1 is used to determine the reference position of the movable member C1. In the illustrated example, the reference mark Z1 is positioned at the center of the magnetic scale C1 and / or the scale body AB1 in the direction of movement. The distance (24 mm) between the two ends of the reference mark Z1 and the magnetic scale C1 in the direction of movement is less than the interval (30 mm) between the multiple magnetic sensors S1 to S5. Furthermore, the distance (16 mm) between the two ends of the reference mark Z1 and the scale body AB1 in the direction of movement is less than the interval (30 mm) between the multiple magnetic sensors S1 to S5.

[0041] The above description of magnetic ruler C1 also applies to other magnetic rulers such as magnetic ruler C2. However, the dimensions of the above parts and the positions of the reference marks are arbitrarily determined on each magnetic ruler. Unless otherwise specified, the description of magnetic ruler C1 also applies to magnetic ruler C2, etc., therefore, repeated descriptions of magnetic ruler C2, etc., are omitted.

[0042] Each magnetic sensor S1 to S5 includes a counting unit 51 to 55, which counts the magnetic scale of phase A / B formed on the scale body AB1 and / or the two ends E1L and E1R of the magnetic scale C1. The direction of increase or decrease of the count value in each counting unit 51 to 55 corresponds to the direction of movement of the magnetic scale C1 (i.e., the movable member C1) detected by each magnetic sensor S1 to S5. For example, when the movable member C1 moves from... Figure 2 When the left side moves towards the right side, the count values ​​in each counting unit 51-55 increase according to the number of A / B phase pulses output by each magnetic sensor S1-S5, while the movable member C1 moves from... Figure 2 When the right side moves towards the left side, the count value in each counting unit 51 to 55 decreases according to the number of A / B phase pulses output by each magnetic sensor S1 to S5.

[0043] As the movable part C1 moves on the guide rail, the magnetic sensors S1 to S5 that measure the position of the magnetic ruler C1 switch sequentially. Figure 3 This schematically illustrates the situation where the measuring body of the magnetic ruler C1, moving from left to right, switches from the magnetic sensor S1 at the movement source to the magnetic sensor S2 at the movement destination. For example... Figure 3As shown, the switching of magnetic sensors S1 and S2 occurs when the scale body AB1 of the magnetic ruler C1 spans the detection range of two adjacent magnetic sensors S1 and S2. In the illustrated example, when magnetic sensors S1 and S2 are located at positions SW1 and SW2 symmetrical to the center (the position of reference mark Z1) relative to the direction of movement of the magnetic ruler C1, the measuring body of the magnetic ruler C1 switches from magnetic sensor S1 to magnetic sensor S2.

[0044] 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. 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. 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. At this time, the distance of the first switching position SW1 from the center of the scale body AB1 and the distance of the second switching position SW2 from the center of the scale body AB1 are 15 mm, and their sum (30 mm) is consistent with the interval of the magnetic sensors S1 and S2.

[0045] When the measuring body of the magnetic ruler C1 switches from magnetic sensor S1 to magnetic sensor S2, the counting value of the counting unit 51 of the moving source magnetic sensor S1 is replaced by the counting value of the counting unit 52 of the moving destination magnetic sensor S2. Hereinafter, the counting values ​​of each of the counting units 51 to 55 when each magnetic sensor S1 to S5 detects the center of the magnetic ruler C1 (the position of reference mark Z1) are set to zero, and each of the magnetic sensors S1 to S5 is positioned on the side opposite to the moving direction of the movable member C1, further from the center of the magnetic ruler C1. Figure 3 (On the left side of the image) When the magnetic scale is detected, the count values ​​of each counting unit 51 to 55 are set to positive, and each magnetic sensor S1 to S5 is positioned closer to the moving part C1 than the center of the magnetic ruler C1 in the direction of movement. Figure 3 The count values ​​of each counting unit 51 to 55 when the magnetic scale is detected (on the right side of the image) are set to negative.

[0046] In the illustrated example, the position of reference mark Z1 corresponds to the count value "0", the first switching position SW1 corresponds to the count value "+15,000" for example, and the second switching position SW2 corresponds to the count value "-15,000" for example. Hereinafter, the count value "+15,000" of the first switching position SW1 will be referred to as the switching count value, and the count value "-15,000" of the second switching position SW2 will be referred to as the start count value. In the illustrated example, the switching count value and the start count value differ only in sign. In the illustrated state, if the first switching position SW1 of the magnetic ruler C1 moves onto the magnetic sensor S1, the switching count value "+15,000" of its counting unit 51 is converted into the start count value "-15,000" of the counting unit 52 of the magnetic sensor S2 located at the second switching position SW2. Subsequently, the magnetic sensor S2 becomes the measuring body of the magnetic ruler C1, and its counting unit 52 counts from the starting counting value "-15,000" to the switching counting value "+15,000" of the next magnetic sensor S3.

[0047] Figure 2 The reference mark detection control unit 40 includes: a reference mark detection activating unit 41 that activates the detection of reference mark Z1 of each magnetic sensor S1 to S5 based on the count values ​​of each counting unit 51 to 55; and a reference mark detection deactivating unit 42 that deactivates the detection of reference mark Z1 of each magnetic sensor S1 to S5 based on the count values ​​of each counting unit 51 to 55.

[0048] Before explaining the detection control of the reference mark Z1 based on the reference mark detection validation unit 41 and / or the reference mark detection invalidation unit 42, Figure 4 and Figure 5 Other embodiments are shown below. Figure 4 As shown, when the movable part C1 is used for the first time in the linear conveying system 1, it is necessary to use multiple magnetic sensors (in...) Figure 4 In this example, any one of the magnetic sensors S1 and S2 is used to detect the reference mark Z1 of the magnetic ruler C1, thereby determining or registering the reference position or initial position of the movable part C1. Each magnetic sensor S1 and S2 must reliably detect the reference mark Z1 and be able to determine that the reference mark Z1 is a mark of the movable part C1. Therefore, in order to prevent false detection of the reference mark Z1 and / or the movable part C1, each magnetic sensor S1 and S2 is in principle in a state where it cannot detect the reference mark Z1. The detection of the reference mark Z1 is only effective when it can reliably detect both the reference mark Z1 and the movable part C1.

[0049] like Figure 4 As shown, assume that a movable part C1 with no registered initial position in the linear conveying system 1 moves along the guide rail from the left side to the right side of the magnetic sensor S1. Figure 4In this state, the position of the magnetic ruler C1 is not above either magnetic sensor S1 or S2. Figure 5 The middle is represented as "S1 left". In this "S1 left" state, since none of the magnetic sensors S1 and S2 detect the magnetic scale of phase A / B of the magnetic scale C1, the counting units 51 and 52 are schematically represented. Figure 2 ) count value Figure 5 Both "S1-A / B phase" and "S2-A / B phase" are "0".

[0050] If the movable part C1 is from Figure 4 The magnetic scale C1 moves until at least the right end E1R of the magnetic scale C1 comes onto the magnetic sensor S1. The magnetic sensor S1 then detects the A / B phase magnetic scale formed on the right end E1R and / or the scale body AB1. The count value in the counting unit 51 increases corresponding to the number of A / B phase pulses from the magnetic sensor S1. Figure 5 In the example, if the "scale position" of the magnetic scale C1 switches from "S1 left" to "S1 up", it indicates that the count value of the counting unit 51, "S1-A / B phase", increases from "1" to "12". In this "S1 up" state, the magnetic scale C1 is not above the magnetic sensor S2, and the magnetic sensor S2 cannot detect the magnetic scale of the A / B phase of the magnetic scale C1. Therefore, it indicates that the count value of the counting unit 52, "S2-A / B phase", remains "0". Furthermore, in this embodiment, for simplicity, it is assumed that the numerical value "18" represents the total length of a magnetic scale. However, in actual linear conveying systems 1, the count value of each magnetic scale is very large, for example, as described above. Figure 3 The description states that the count value is approximately "30,000" ("-15,000" to "+15,000").

[0051] exist Figure 5 The "Z" in the "S1-Z phase" column when the count value of "S1-A / B phase" becomes "9" indicates that the reference marker Z1 has moved above the magnetic sensor S1. However, as mentioned above, since the magnetic sensor S1 is in principle unable to detect the reference marker Z1 ("S1-Z detection" becomes "undetectable"), it cannot detect the reference marker Z1 when the count value of "S1-A / B phase" becomes "9".

[0052] exist Figure 5During the period when the count value of "S1-A / B phase" is "13" to "18", the magnetic ruler C1 is in the "S1 & S2 on" state, which means that the magnetic ruler C1 is above both magnetic sensors S1 and S2. Specifically, the part of the magnetic ruler C1 that is further to the left than the reference mark Z1 (the left end E1L or the left part of the ruler body AB1) is above the magnetic sensor S1, and the part of the magnetic ruler C1 that is further to the right than the reference mark Z1 (the right end E1R or the right part of the ruler body AB1) is above the magnetic sensor S2. In this "S1 & S2 on" state, all magnetic sensors S1 and S2 detect the magnetic scale of the A / B phase of the magnetic ruler C1. Therefore, the "S1-A / B phase" and "S2-A / B phase" representing the count values ​​of each counting unit 51 and 52 increase in the same way.

[0053] In this embodiment, if the "S1-A / B phase" and the "S2-A / B phase" continuously increase or decrease a predetermined count value (in the illustrated example, the count value is "3") in the same direction at approximately the same time, then the detection of the reference mark Z1 of the magnetic sensor on the direction of increase or decrease (i.e., the direction of movement of the movable member C1) is enabled. In the illustrated example, since the increase of "13" to "15" in the "S1-A / B phase" and the increase of "1" to "3" in the "S2-A / B phase" continuously generate a count value of "3" at approximately the same time, the detection of the reference mark Z1 of the magnetic sensor S2 on the direction of increase (i.e., the direction of movement from the left side to the right side of the movable member C1) (i.e., the right side) is enabled. Thus, after the count value of the "S2-A / B phase" reaches "4", the "S2-Z detection" switches from "not possible" to "possible".

[0054] In this state, if the count value of "S2-A / B phase" becomes "9", then the reference mark Z1 comes onto the magnetic sensor S2 (a "Z" appears in the "S2-Z phase" column), so the magnetic sensor S2 will detect the reference mark Z1, and the initial position of the movable member C1 is registered in the linear conveying system 1. Furthermore, at the moment when the count value of "S2-A / B phase" is "9", the magnetic ruler C1 has passed through the magnetic sensor S1 and reached its right side, so the "ruler position" becomes "on S2", indicating that the magnetic ruler C1 is (only) located on the magnetic sensor S2, and the count value of "S1-A / B phase" remains unchanged at its maximum value of "18".

[0055] As mentioned above, in Figure 4 and Figure 5In this embodiment, the detection of the reference mark Z1 of the magnetic sensor S2 on the moving direction side of the movable member C1 is effective only when the count values ​​of two adjacent magnetic sensors S1 and S2 change continuously by a predetermined count value at approximately the same time and in the same direction. Therefore, the reference mark Z1 of the movable member C1, which is simultaneously detected by the two magnetic sensors S1 and S2, can be reliably detected by the magnetic sensor S2 of the moving destination. However, when two movable members that are close to each other move at the same speed, the situation is that the count values ​​of the two adjacent magnetic sensors that detect each movable member change continuously by a predetermined count value at approximately the same time and in the same direction. Therefore, false detection of the reference mark and / or the movable member may occur. According to the embodiment described below, by Figure 2 The structure shown (especially the reference mark detection validation unit 41 and / or the reference mark detection invalidation unit 42) can further reduce the possibility of falsely detecting reference marks and / or movable parts.

[0056] exist Figure 2 In this process, the reference mark detection activation unit 41 activates the detection of reference marks Z1 and Z2 of the other magnetic sensors S1 to S5 based on the count values ​​in each of the counting units 51 to 55, and when the magnetic rulers C1 and C2 move from a state that spans the detection range of two adjacent magnetic sensors S1 / S2, S2 / S3, S3 / S4, S4 / S5 to outside the detection range of one of the magnetic sensors S1 to S5.

[0057] exist Figure 6 and Figure 7 In the simplified embodiment shown, the reference marker detection validation unit 41 determines the validity of the data based on the counting units 51 and 52 (in...). Figure 6 The count value (not shown) and the detection of the reference mark Z1 of the other magnetic sensor S2 on the moving direction side of the movable member C1 when the magnetic ruler C1 moves from a state that spans the detection range of the two adjacent magnetic sensors S1 / S2 to outside the detection range of one of the magnetic sensors S1 as shown by the dashed line.

[0058] like Figure 7 As shown, with Figure 5 Similarly, when the count values ​​of the counting units 51 and 52 in the two adjacent magnetic sensors S1 and S2 change in the same way (in the illustrated example, while the count value of magnetic sensor S1 increases to "13" to "15", the count value of magnetic sensor S2 increases to "1" to "3"), the reference mark detection activation unit 41 determines that the magnetic ruler C1 is located in the state of "on S1 & S2" spanning the two adjacent detection ranges. In this state of "on S1 & S2", the magnetic ruler C1 is located above both magnetic sensors S1 and S2 (e.g., Figure 6(As shown by the solid line in the middle). At this time, the reference mark Z1 is located in a position that is sandwiched between the detection ranges of two adjacent magnetic sensors S1 and S2.

[0059] like Figure 7 As shown, the magnetic ruler C1 remains in a state spanning the two adjacent detection ranges "S1 & S2" until the count value of magnetic sensor S1 becomes "18" and the count value of magnetic sensor S2 becomes "6". Furthermore, if the count value of magnetic sensor S1 remains at "18" while only the count value of magnetic sensor S2 increases to "7", then... Figure 6 As shown by the dashed line, the movable member C1 moves outside the detection range of the magnetic sensor S1 on the opposite side of the movement direction, thus entering the "S2 on" state. Therefore, the reference mark detection activation unit 41 activates the detection of the reference mark Z1 of the other magnetic sensor S2 on the movement direction side of the movable member C1 when only the count value of the magnetic sensor S2 increases to "7". Furthermore, the reference mark detection activation unit 41 can also activate the detection of the reference mark Z1 of the other magnetic sensor S2 on the movement direction side of the movable member C1 when the magnetic sensor S1 cannot detect the magnetic scale of the A / B phase of the magnetic ruler C1.

[0060] like Figure 6 As shown by the dashed line, the reference marker Z1 is still located within the detection range of two adjacent magnetic sensors S1 and S2. Therefore, only by moving the movable member C1 further in the same direction can the reference marker Z1 reach the magnetic sensor S2. Specifically, when the count value of the magnetic sensor S2 becomes "9", the reference marker Z1 reaches the magnetic sensor S2 (a "Z" appears in the "S2-Z phase" column). Therefore, the magnetic sensor S2 will detect the reference marker Z1, and the initial position of the movable member C1 is registered in the linear conveying system 1. If the other magnetic sensor S2 on the moving direction side, which is activated by the reference marker detection activation unit 41 when the S2 count value is "7", detects the reference marker Z1 when the S2 count value is "9",... Figure 2 The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z1 of the other magnetic sensor S2 after the S2 count value is "10" (sets "S2-Z detection" to "not possible").

[0061] Next, the case with multiple movable parts will be explained. In this case, two movable parts that are close to each other (i.e., magnetic scales) may simultaneously enter the detection range of a magnetic sensor. Therefore, it is preferable to take precautions beforehand, such as... Figure 8 The measures shown are for preventing false detections by the magnetic rulers.

[0062] Figure 8This schematically illustrates the state where two magnetic rulers C1 and C2, approaching each other to their minimum approach distance, simultaneously enter the detection range R of a magnetic sensor S1 to S5. In this example, the minimum approach distance between the two magnetic rulers C1 and C2 (the distance between the right end of magnetic ruler C1 and the left end of magnetic ruler C2 in the illustrated state) is 2 mm, and the track direction of the detection range R of the magnetic sensors S1 to S5 (…) Figure 8 The length in the left-right direction is 5mm. As described above, the right end E1R of magnetic ruler C1 and the left end E2L of magnetic ruler C2 have A / B phase magnetic scales formed in the same way as the scale body AB1 of magnetic ruler C1 and the scale body AB2 of magnetic ruler C2. Therefore, in the illustrated state, magnetic sensors S1 to S5 will simultaneously detect the A / B phase magnetic scales of the right end E1R and the left end E2L. At this time, magnetic sensors S1 to S5 cannot distinguish between detecting the two magnetic rulers C1 and C2.

[0063] To prevent false detections of the two magnetic rulers C1 and C2 which are so close together, shielding components B1R and / or B2L are provided to shield the right end E1R of magnetic ruler C1 and / or the left end E2L of magnetic ruler C2 from the detection range R of magnetic sensors S1 to S5.

[0064] The shielding component B1R at least shields the magnetic scale of phase A / B located on the right side of the right end E1R of the magnetic scale C1, away from the scale body AB1. Specifically, as described above, the right end portion of the 8mm long right end E1R is shielded by the shielding component B1R. If the length of the shielding component B1R in the track direction is set to the length in the track direction of the detection range R of the magnetic sensors S1 to S5 (5mm) or more, the shielding component B1R alone can shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic scale C1 and magnetic scale C2 from being detected simultaneously. Furthermore, if the length of the shielding component B1R in the track direction is set to the length obtained by subtracting the minimum approach distance (2mm) of the movable parts C1 and C2 from the length in the track direction of the detection range R of the magnetic sensors S1 to S5 (5mm) (3mm) or more, the shielding component B1R alone can substantially shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic scale C1 and magnetic scale C2 from being detected simultaneously. Furthermore, if the length of the shielding component B1R in the track direction is set to more than half (1.5mm) of the length obtained by subtracting the minimum approach distance (2mm) of the movable parts C1 and C2 from the length (5mm) in the track direction of the detection range R of the magnetic sensors S1 to S5, together with the shielding component B2L of the same length, it can substantially shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic rulers C1 and C2 from being detected simultaneously.

[0065] The shielding component B2L at least shields the magnetic graduations of the A / B phase located on the left side of the left end E2L of the magnetic scale, which is far from the scale body AB2. Specifically, as described above, the left end portion of the 8mm long left end E2L is shielded by the shielding component B2L. If the length of the shielding component B2L in the track direction is set to the length in the track direction of the detection range R of the magnetic sensors S1 to S5 (5mm) or more, the shielding component B2L alone can shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic scale C2 and magnetic scale C1 from being detected simultaneously. Furthermore, if the length of the shielding component B2L in the track direction is set to the length obtained by subtracting the minimum approach distance (2mm) of the movable parts C1 and C2 from the length in the track direction of the detection range R of the magnetic sensors S1 to S5 (5mm) (3mm) or more, the shielding component B2L alone can substantially shield the detection range R of the magnetic sensors S1 to S5, thereby preventing the magnetic scale C2 and magnetic scale C1 from being detected simultaneously. Furthermore, if the length of the shielding component B2L in the track direction is set to more than half (1.5mm) of the length obtained by subtracting the minimum approach distance (2mm) of the movable parts C1 and C2 from the length (5mm) in the track direction of the detection range R of the magnetic sensors S1 to S5, together with the shielding component B1R of the same length, the detection range R of the magnetic sensors S1 to S5 can be substantially shielded, thereby preventing the magnetic ruler C2 and the magnetic ruler C1 from being detected simultaneously.

[0066] In magnetic ruler C1, a shielding component identical to the shielding component B1R at the right end (or the shielding component B2L at the left end of magnetic ruler C2) may be provided at the left end (not shown), or a shielding component may be provided only at the left end. Similarly, in magnetic ruler C2, a shielding component identical to the shielding component B2L at the left end (or the shielding component B1R at the right end of magnetic ruler C1) may be provided at the right end (not shown), or a shielding component may be provided only at the right end.

[0067] The shielding component B1R and / or shielding component B2L are formed of a strongly magnetic material that magnetically shields at least one end of the magnetic scale C1 and / or magnetic scale C2 from the magnetic sensors S1 to S5. Examples of strongly magnetic materials include metals or alloys such as iron, cobalt, nickel, gadolinium, and manganese. Furthermore, when an optical scale is used instead of a magnetic scale as the position measuring scale, the shielding component can be formed solely from the light-shielding material of the optically shielded position detection unit (i.e., the optical sensor). As described above, by adopting... Figure 8 Such a measure can prevent the two measuring scales from being falsely detected by the position detection unit at the same time, even if the ends of the measuring scales of two movable parts that are close to each other simultaneously enter the detection range of a position detection unit, by providing a shielding member on at least one of the ends.

[0068] Next, regarding Figure 4 and Figure 5 In the embodiments (embodiments that do not use the reference mark detection validation unit 41 and / or the reference mark detection invalidation unit 42), several embodiments in which the reference mark and / or the movable member may be misdetected, and two movable members that are close to each other move at the same speed.

[0069] exist Figure 9 and Figure 10 In the first embodiment shown, in Figure 9 In the initial state shown (the state where movable parts C1 and C2, whose initial positions are not registered, begin to move to the right), movable part C1 is positioned above both magnetic sensors S2 and S3, and movable part C2 is positioned above magnetic sensor S4. Figure 10 As shown, the reference mark detection activation unit 41 activates the detection of the reference mark Z1 of the other magnetic sensor S3 on the moving direction side of the movable member C1 based on the count values ​​in the counting units 52 and 53 and when the magnetic ruler C1 moves from a state that spans the detection range of two adjacent magnetic sensors S2 and S3 to outside the detection range of one of the magnetic sensors S2.

[0070] If the movable member C1 moves further in the same direction in this state, the reference mark Z1 will come onto the magnetic sensor S3. Therefore, the magnetic sensor S3 will detect the reference mark Z1, and the initial position of the movable member C1 will be registered in the linear conveying system 1. The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z1 by the magnetic sensor S3 after the magnetic sensor S3 detects the reference mark Z1. Furthermore, if the magnetic ruler C1 moves from a state spanning the detection range of two adjacent magnetic sensors S3 and S4 to outside the detection range of one of the magnetic sensors S3, however, since the reference mark Z1 of the magnetic ruler C1 has been detected by the magnetic sensor S3, the detection of the reference mark Z1 by the magnetic sensor S4 will not become valid.

[0071] On the other hand, the reference mark detection activation unit 41, based on the count values ​​in the counting units 54 and 55, and when the magnetic ruler C2 moves from a state spanning the detection range of two adjacent magnetic sensors S4 and S5 to outside the detection range of one of the magnetic sensors S4, activates the detection of the reference mark Z2 of the other magnetic sensor S5 on the moving direction side of the movable member C2. If the movable member C2 moves further in the same direction in this state, the reference mark Z2 will come onto the magnetic sensor S5, and therefore, the magnetic sensor S5 will detect the reference mark Z2, and the initial position of the movable member C2 will be registered in the linear conveying system 1. The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z2 by the magnetic sensor S5 after the magnetic sensor S5 detects the reference mark Z2. As described above, even when two movable members C1 and C2 that are close to each other move at the same speed, the reference marks Z1 and Z2 of each movable member C1 and C2 can be reliably detected.

[0072] exist Figure 11 and Figure 12 In the second embodiment shown, in Figure 11 In the initial state shown, movable member C1 is positioned above magnetic sensor S2, and movable member C2 is positioned above both magnetic sensors S3 and S4. Figure 12 As shown, the reference mark detection activation unit 41 activates the detection of the reference mark Z2 of the other magnetic sensor S4 on the moving direction side of the movable member C2 based on the count values ​​in the counting units 53 and 54 and when the magnetic ruler C2 moves from a state that spans the detection range of two adjacent magnetic sensors S3 and S4 to outside the detection range of one of the magnetic sensors S3.

[0073] If the movable member C2 moves further in the same direction in this state, the reference mark Z2 will come onto the magnetic sensor S4. Therefore, the magnetic sensor S4 will detect the reference mark Z2, and the initial position of the movable member C2 will be registered in the linear conveying system 1. The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z2 by the magnetic sensor S4 after the magnetic sensor S4 detects the reference mark Z2. Furthermore, if the magnetic ruler C2 moves from a state spanning the detection range of two adjacent magnetic sensors S4 and S5 to outside the detection range of one of the magnetic sensors S4, however, since the reference mark Z2 of the magnetic ruler C2 has been detected by the magnetic sensor S4, the detection of the reference mark Z2 by the magnetic sensor S5 will not become valid.

[0074] On the other hand, the reference mark detection activation unit 41, based on the count values ​​in the counting units 52 and 53, and when the magnetic ruler C1 moves from a state spanning the detection range of two adjacent magnetic sensors S2 and S3 to outside the detection range of one of the magnetic sensors S2, activates the detection of the reference mark Z1 of the other magnetic sensor S3 on the moving direction side of the movable member C1. If the movable member C1 moves further in the same direction in this state, the reference mark Z1 will come onto the magnetic sensor S3, and therefore, the magnetic sensor S3 will detect the reference mark Z1, and the initial position of the movable member C1 will be registered in the linear conveying system 1. The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z1 by the magnetic sensor S3 after the magnetic sensor S3 detects the reference mark Z1. As described above, even when two movable members C1 and C2 that are close to each other move at the same speed, the reference marks Z1 and Z2 of each movable member C1 and C2 can be reliably detected.

[0075] exist Figure 13 and Figure 14 In the third embodiment shown, in Figure 13 In the initial state shown, movable member C1 is positioned above both magnetic sensors S1 and S2, and movable member C2 is positioned above both magnetic sensors S3 and S4. Figure 14 As shown, the reference mark detection activation unit 41 activates the detection of the reference mark Z1 of the other magnetic sensor S2 on the moving direction side of the movable member C1 based on the count values ​​in the counting units 51 and 52 and when the magnetic ruler C1 moves from a state that spans the detection range of two adjacent magnetic sensors S1 and S2 to outside the detection range of one of the magnetic sensors S1.

[0076] If the movable member C1 moves further in the same direction in this state, the reference mark Z1 will come onto the magnetic sensor S2. Therefore, the magnetic sensor S2 will detect the reference mark Z1, and the initial position of the movable member C1 will be registered in the linear conveying system 1. The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z1 by the magnetic sensor S2 after the magnetic sensor S2 detects the reference mark Z1. Furthermore, if the magnetic ruler C1 moves from a state spanning the detection range of two adjacent magnetic sensors S2 and S3 to outside the detection range of one of the magnetic sensors S2, however, since the reference mark Z1 of the magnetic ruler C1 has been detected by the magnetic sensor S2, the detection of the reference mark Z1 by the magnetic sensor S3 will not become valid.

[0077] On the other hand, the reference mark detection activation unit 41 activates the detection of the reference mark Z2 of the other magnetic sensor S4 on the moving direction side of the movable member C2 based on the count values ​​in the counting units 53 and 54 and when the magnetic ruler C2 moves from a state that spans the detection range of two adjacent magnetic sensors S3 and S4 to outside the detection range of one of the magnetic sensors S3.

[0078] If the movable member C2 moves further in the same direction in this state, the reference mark Z2 will come onto the magnetic sensor S4. Therefore, the magnetic sensor S4 will detect the reference mark Z2, and the initial position of the movable member C2 will be registered in the linear conveying system 1. The reference mark detection invalidation unit 42 invalidates the detection of the reference mark Z2 by the magnetic sensor S4 after the magnetic sensor S4 detects the reference mark Z2. Furthermore, although the illustration is omitted, there is a case where the magnetic ruler C2 moves from a state spanning the detection range of two adjacent magnetic sensors S4 and S5 to outside the detection range of one of the magnetic sensors S4. However, since the reference mark Z2 of the magnetic ruler C2 has been detected by the magnetic sensor S4, the detection of the reference mark Z2 of the magnetic sensor S5 will not become valid. As described above, even when the two movable members C1 and C2 that are close to each other move at the same speed, the reference marks Z1 and Z2 of each movable member C1 and C2 can be reliably detected.

[0079] In the first to third embodiments described above, the movement direction of each movable member C1 and C2 is constant. However, even if the movement direction of each movable member C1 and C2 changes, the reference marks Z1 and Z2 of each movable member C1 and C2 can be reliably detected. For example, after the reference mark detection activating unit 41 activates another (e.g., the right side) magnetic sensor and before that other magnetic sensor detects the reference marks Z1 and Z2, if the magnetic rulers C1 and C2 return to a state spanning the detection range of one (e.g., the left side) magnetic sensor and the other magnetic sensor, and further move outside the detection range of the other magnetic sensor, then the reference mark detection activating unit 41 activates the detection of the reference marks Z1 and Z2 of one magnetic sensor.

[0080] At this time, the reference mark detection invalidation unit 42 can invalidate the detection of reference marks Z1 and Z2 of the other magnetic sensor if, after the reference mark detection validation unit 41 has validated the other magnetic sensor and before the other magnetic sensor detects reference marks Z1 and Z2, the magnetic rulers C1 and C2 return to a state spanning the detection range of one magnetic sensor and the other magnetic sensor, and further move outside the detection range of the other magnetic sensor. Alternatively, the reference mark detection invalidation unit 42 can also invalidate the detection of reference marks Z1 and Z2 of the other magnetic sensor if, after the reference mark detection validation unit 41 has validated the other magnetic sensor and before the other magnetic sensor detects reference marks Z1 and Z2, the magnetic rulers C1 and C2 return to a state spanning the detection range of one magnetic sensor and the other magnetic sensor.

[0081] The present invention has been described above with reference to embodiments. Those skilled in the art should understand that the embodiments are merely illustrative, and various modifications may exist in the combination of the constituent elements or processing steps, and such modifications are also within the scope of the present invention.

[0082] The embodiments illustrate a linear transport system that drives a movable member based on the magnetic force between a permanent magnet disposed on a movable member and an electromagnet disposed on a fixed member. However, the present invention can also be applied to any drive device based on any principle other than magnetism (e.g., electricity or fluid).

[0083] Furthermore, the functional structures of the devices described in the embodiments can be implemented using hardware resources, software resources, or a combination of hardware and software resources. As hardware resources, processors, ROMs, RAMs, and other LSIs can be used. As software resources, operating systems, applications, and other programs can be used.

Claims

1. A positioning device, characterized in that, have: Multiple position detection units are arranged along the moving direction of the movable member in order to measure the position of the measuring scale mounted on the movable member, and the interval between them is less than the length of the measuring scale in the moving direction. They detect the reference mark set on the movable member to determine the reference position of the movable member. as well as The reference mark detection activating unit activates the detection of the reference mark of the other position detection unit when the measuring scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units.

2. The positioning device according to claim 1, characterized in that, It also includes a reference mark detection invalidation unit, which invalidates the detection of the reference mark by the other position detection unit when the reference mark is detected by the other position detection unit which is validated by the reference mark detection validation unit.

3. The positioning device according to claim 1 or 2, characterized in that, It also includes a reference mark detection invalidation unit, which invalidates the detection of the reference mark by the other position detection unit when the other position detection unit has been activated by the reference mark detection activation unit and the other position detection unit has detected the reference mark, and the measuring scale returns to a state spanning the detection range of the one position detection unit and the other position detection unit and has further moved outside the detection range of the other position detection unit.

4. The positioning device according to claim 1 or 2, characterized in that, It also includes a reference mark detection invalidation unit, which invalidates the detection of the reference mark by the other position detection unit when the positioning scale returns to a state spanning the detection range of the one position detection unit and the other position detection unit after the reference mark detection validation unit has made the other position detection unit valid and before the other position detection unit detects the reference mark.

5. The positioning device according to any one of claims 1 to 4, characterized in that, After the reference mark detection activating unit activates the other position detection unit and before the other position detection unit detects the reference mark, the positioning scale returns to a state spanning the detection range of the one position detection unit and the other position detection unit, and further moves outside the detection range of the other position detection unit, the reference mark detection activating unit makes the detection of the reference mark of the one position detection unit valid.

6. The positioning device according to any one of claims 1 to 5, characterized in that, The measuring scale has multiple graduations set along the direction of movement. The position detection unit includes a counting unit that counts the detected scale divisions. If the count values ​​of the counting units in two adjacent position detection units change in the same way, the reference mark detection validation unit determines that the positioning scale is in a state spanning two adjacent detection ranges.

7. The positioning device according to any one of claims 1 to 6, characterized in that, With the measuring scale spanning the detection range of two adjacent position detection units, the reference mark is located between the two detection ranges.

8. The positioning device according to any one of claims 1 to 7, characterized in that, The distance between the two ends of the reference mark and the measuring scale in the direction of movement is less than the interval between the plurality of position detection units.

9. A driving device, characterized in that, have: Multiple movable parts drive along the track; Multiple position detection units are arranged along the track to measure the position of the measuring scales installed on each movable member, and the interval between them is less than the length of the measuring scales in the track direction. They detect the reference marks set on each movable member to determine the reference position of each movable member. as well as The reference mark detection activating unit activates the detection of the reference mark of the other position detection unit when the measuring scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units.

10. A positioning method, characterized in that, It is used in positioning devices. The positioning device includes multiple position detection units. These multiple position detection units are arranged along the movement direction of the movable member to measure the positioning scale mounted on the movable member, and the distance between them is less than the length of the positioning scale in the movement direction. They detect a reference mark set on the movable member to determine the reference position of the movable member. The positioning method includes a reference mark detection validation step, which is as follows: when the positioning scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark of the other position detection unit becomes valid.

11. A storage medium storing a bit-detection program, characterized in that, The positioning program is a positioning program used for the positioning device. The positioning device includes multiple position detection units. These multiple position detection units are arranged along the movement direction of the movable member to measure the positioning scale mounted on the movable member, and the distance between them is less than the length of the positioning scale in the movement direction. They detect a reference mark set on the movable member to determine the reference position of the movable member. The positioning program is executed by a computer to perform a reference mark detection validity step, which is as follows: when the positioning scale moves from a state spanning the detection range of two adjacent position detection units to outside the detection range of one of the position detection units, the detection of the reference mark performed by the other position detection unit becomes valid.

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