Processor, processing system and work-piece manufacturing method

Abstract

To improve accuracy of detection by a two-dimensional scale.SOLUTION: In a processor 1, a Z-axis table 9Z supports a work-piece 103. A Z-axis guide 17Z guides the Z-axis table 9Z in a Z direction. A Z-axis sensor 25Z outputs a signal in response to first displacement of the Z-axis table 9Z in the Z direction and a first error which is displacement of the Z-axis table 9Z in an X direction. A work spindle 15W has a constant positional relationship with the Z-axis guide 17Z in the Y direction. Further, the work spindle 15W rotates the work-piece 103 around a work-piece rotation axis AW parallel to the Z direction or the X direction. When assuming a virtual plane VP which includes the work-piece rotation axis AW and is parallel to the X direction and the Z direction, a distance from the virtual plane VP to the Z-axis sensor 25Z is less than 1 / 3 of a distance hr from the virtual plane VP to the Z-axis guide 17Z.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a processing machine, a processing system, and a method for manufacturing a workpiece. [Background technology]

[0002] There is known a processing machine that processes a workpiece using a tool (for example, see Patent Document 1 below). In such a processing machine, for example, a movable part that supports the tool or the workpiece is guided by a linear guide, thereby realizing relative movement between the tool and the workpiece. Ideally, the movable part moves in a straight line along the linear guide. However, in reality, due to various factors, the movable part moves while generating undulations. In other words, the straightness or squareness is not 0. This undulation reduces the processing accuracy.

[0003] The following Patent Document 1 proposes a processing machine that improves straightness by detecting the displacement of a movable part using a two-dimensional scale (sometimes referred to as a two-dimensional linear encoder, etc.). Specifically, the processing machine of Patent Document 1 has, as movable parts that support a tool or a workpiece, a first movable part guided in a first direction by a first linear guide and a second movable part guided in a second direction perpendicular to the first direction by a second linear guide. The two-dimensional scale detects the displacement of the first movable part in the first direction and the displacement (error) of the first movable part in the second direction. Then, when an error in the second direction is detected by the two-dimensional scale, the processing machine controls the position of the second movable part in the second direction so as to compensate for (in other words, to cancel) the effect of the error on the relative position between the tool and the workpiece.

[0004] The following Patent Document 2 relates to a stage device used in the manufacture of semiconductors and the like, rather than a processing machine that processes a workpiece with a tool, but discloses a technology that utilizes a two-dimensional scale. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-24542 [Patent Document 2] JP 2015-109079 A Summary of the Invention [Problem to be solved by the invention]

[0006] There is a need for a processing machine, a processing system, and a method for manufacturing a workpiece that can improve the accuracy of detection using a two-dimensional scale. [Means for solving the problem]

[0007] A machining machine according to one embodiment of the present disclosure comprises a first movable part that supports a workpiece or a tool, a linear guide that guides the first movable part in a first direction, a two-dimensional scale that outputs a signal corresponding to a first displacement of the first movable part in the first direction and a first error, which is a displacement of the first movable part in a second direction perpendicular to the first direction, and a main shaft that has a certain positional relationship with the linear guide in a third direction perpendicular to the first direction and the second direction and rotates the workpiece or the tool around a first rotation axis parallel to the first direction or the second direction, wherein when a virtual plane is assumed that includes the first rotation axis and is parallel to the first direction and the second direction, the distance from the virtual plane to the two-dimensional scale is less than 1 / 3 of the distance from the virtual plane to the linear guide.

[0008] A machining machine according to one embodiment of the present disclosure comprises a support portion having a first surface facing a third direction perpendicular to a first direction and a second direction, a fixed portion supported on the first surface, a first movable portion supporting a workpiece or a tool, supported on the fixed portion via a linear guide and guided in the first direction relative to the fixed portion by the linear guide, a scale arrangement portion supported on the first surface and spaced from the fixed portion, and a two-dimensional scale outputting a signal corresponding to a first displacement of the first movable portion in the first direction and a first error, which is a displacement of the first movable portion in the second direction, the two-dimensional scale comprising a scale portion fixed to the scale arrangement portion and a detection portion fixed to the first movable portion and outputting a signal corresponding to relative movement with the scale portion, the scale arrangement portion having a height that exceeds the position of the linear guide on the side facing the first surface, and the scale portion being positioned on the side facing the first surface relative to the linear guide.

[0009] A processing system according to one embodiment of the present disclosure includes the above-mentioned processing machine and a diagnostic device that acquires information on the detection value of the first error from the processing machine and displays an image according to the acquired information.

[0010] A method for manufacturing a workpiece according to one aspect of the present disclosure includes a step of using the above-mentioned processing machine to bring the workpiece into contact with the tool and process the workpiece into a workpiece. Effect of the Invention

[0011] According to the above configuration or procedure, it is possible to improve the accuracy of detection using a two-dimensional scale. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view showing a configuration of a processing machine according to a first embodiment. [Diagram 2] 2 is a schematic perspective view showing the processing machine of FIG. 1 with a configuration related to a two-dimensional scale removed; [Diagram 3]3(a) and 3(b) are diagrams for explaining the configuration and operation of a two-dimensional scale. [Figure 4] FIG. 2 is a block diagram showing the configuration of a control system in the processing machine of FIG. 1 . [Diagram 5] FIG. 5 is a diagram showing details of a portion of the block diagram of FIG. 4. [Figure 6] FIG. 4 is a diagram for explaining a method of calculating an error due to a roll. [Figure 7] FIG. 4 is a diagram for explaining a method of calculating an error due to yaw. [Figure 8] FIG. 11 is a block diagram showing the configuration of a control system in a processing machine according to a second embodiment. [Figure 9] 9 is a diagram for explaining the configuration of the three-dimensional scale in FIG. 8 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Overview of the embodiment) Fig. 1 is a schematic perspective view showing the configuration of a processing machine 1 according to an embodiment. Fig. 2 is a view of Fig. 1 excluding the configuration related to a two-dimensional scale. For convenience, these figures are given an orthogonal coordinate system XYZ. The +Y direction is, for example, vertically upward.

[0014] The technology according to the present disclosure can be applied to various processing machines, and the processing machine 1 shown in the figure is merely one example. However, in the following description, for the sake of convenience, the description may be given on the premise that the configuration of the processing machine 1 is used.

[0015] The processing machine 1 processes (e.g., grinds and / or polishes) a workpiece 103 by, for example, a tool 101. More specifically, in the illustrated example, the workpiece 103 is rotated about a workpiece rotation axis AW parallel to the Z axis. The tool 101 is made of a grindstone, and is rotated about a tool rotation axis AT parallel to the Y axis. The tool 101 is brought into contact with the workpiece 103, thereby grinding and / or polishing the workpiece 103. Such a processing machine 1 can be used, for example, as an aspherical processing machine for producing aspherical lenses, etc.

[0016] Each of the multiple movable parts (X-axis table 9X, saddle 13, and Z-axis table 9Z) that support the tool 101 or workpiece 103 moves in parallel along the X-axis, Y-axis, or Z-axis. This allows the tool 101 and workpiece 103 to move relatively in any direction. This parallel movement is achieved by each movable part being guided by a linear guide (X-axis guide 17X, Y-axis guide 17Y, or Z-axis guide 17Z). Furthermore, the displacement of the parallel movement of each movable part is detected by a two-dimensional scale (X-axis sensor 25X, Y-axis sensor 25Y, or Z-axis sensor 25Z), as shown in FIG. 1. The detected displacement is used, for example, for feedback control of the parallel movement.

[0017] The two-dimensional scale can detect not only the displacement in the direction (first direction) in which each movable part should move in parallel, but also the displacement (error) in the direction (second direction) perpendicular to the first direction. For example, the X-axis sensor 25X detects the displacement (error) in the Z direction (second direction) of the X-axis table 9X in addition to the displacement in the X direction (first direction) of the X-axis table 9X. The Y-axis sensor 25Y detects the displacement (error) in the Z direction (second direction) of the saddle 13 in addition to the displacement in the Y direction (first direction) of the saddle 13. The Z-axis sensor 25Z detects the displacement (error) in the X direction (second direction) of the Z-axis table 9Z in addition to the displacement in the Z direction (first direction) of the Z-axis table 9Z.

[0018] By detecting an error using the two-dimensional scale as described above, for example, the processing machine 1 can be controlled to compensate for an error in the relative position between the tool 101 and the workpiece 103 caused by the error. For example, when an error in the Z direction of the X-axis table 9X is detected by the X-axis sensor 25X, the error in the relative position between the tool 101 and the workpiece 103 can be reduced by displacing the Z-axis table 9Z in the same direction and by the same amount as the error. And / or, the error detected by the two-dimensional scale may be used for quality control.

[0019] Here, a virtual plane VP (not shown in Figs. 1 and 2; Fig. 6 shows the virtual plane VP related to the Z-axis sensor 25Z) is assumed, in which the two-dimensional scale is parallel to the two directions in which displacement is detected and which includes the machining point where the tool 101 contacts the workpiece 103. Instead of the machining point, a virtual plane VP including the rotation axis (AW or AT) may be assumed. In this case, the two-dimensional scale is located within the virtual plane VP.

[0020] For example, the X-axis sensor 25X is parallel to the X and Z directions and is located in a virtual plane VP (FIG. 6) that includes the workpiece rotation axis AW. The Y-axis sensor 25Y is parallel to the Y and Z directions and is located in a virtual plane VP (not shown) that includes the tool rotation axis AT. The Z-axis sensor 25Z is parallel to the Z and X directions and is located in a virtual plane VP (FIG. 6) that includes the workpiece rotation axis AW.

[0021] By doing so, as will be described in detail later, the accuracy of the error detected by the two-dimensional scale is improved. In terms of obtaining this effect, the two-dimensional scale does not necessarily need to be located within the virtual plane VP, and may be located in a position close to the virtual plane VP. For example, the distance from the virtual plane VP to the two-dimensional scale may be less than 1 / 2, less than 1 / 3, less than 1 / 5, or less than 1 / 10 of the distance from the virtual plane VP to the linear guide.

[0022] From another point of view, the processing machine 1 has a configuration for bringing the two-dimensional scale closer to the virtual plane VP. Specifically, the processing machine 1 is provided with scale arrangement sections (X-axis scale arrangement section 21X, Y-axis scale arrangement section 21Y, and Z-axis scale arrangement section 21Z) on which parts of the two-dimensional scale (scale sections described later) are provided.

[0023] Taking the X-axis as an example of the three axes, the X-axis scale arrangement section 21X has a height such that its upper surface is positioned above the X-axis guide 17X. A part (scale section) of the X-axis sensor 25X is provided on the upper surface of the X-axis scale arrangement section 21X. As a result, the X-axis sensor 25X is located on the side of the imaginary plane VP with respect to the X-axis guide 17X.

[0024] Note that the configuration for bringing the two-dimensional scale closer to the virtual plane VP does not have to depend on the scale arrangement unit. Also, the scale arrangement unit does not have to contribute to bringing the two-dimensional scale closer to the virtual plane VP. The scale arrangement unit can achieve other effects (described later) in addition to bringing the two-dimensional scale closer to the virtual plane VP.

[0025] The above is an overview of the processing machine 1 according to the embodiment. The following will be roughly explained in the following order. Chapter A First Embodiment 1. Overall configuration of the processing machine (Fig. 1 and Fig. 2) 2. Scale-related configuration 2.1. Scale (Fig. 3(a) and Fig. 3(b)) 2.1.1. Scales in general 2.1.2. Examples of scale construction 2.1.3. Configuration related to detection of rotation error 2.2. Scale arrangement on each axis 2.3.Scale placement section 3. Control System 3.1.Multi-axis control system (Fig. 4) 3.1.1. Overview of Control Signal Processing Feedback Control 3.1.4. Error Compensation 3.2.Control system for each axis (Fig. 5) 3.2.1.Z-axis control based on Z-axis sensor 3.2.2. Controlling the Z-axis based on sensors of other axes Supplementary Information 4. How to calculate the effect of rotation error (Figs. 6 and 7) 4.1. Role Influence 4.2.Yaw effect 4.3. Pitch Effects 5. Processing system (Fig. 1) 6. Summary of the First Embodiment Chapter B. Second embodiment 7. Overall configuration of the second embodiment (FIG. 8) 8. Scale (Figure 9) 9. Summary of the second embodiment

[0026] <Chapter A First Embodiment> (1. Overall configuration of the processing machine) The processing machine 1 has, for example, a machine body 3 that holds a tool 101 and a workpiece 103 , and a controller 5 that controls the machine body 3 .

[0027] As described above, the machine body 3 rotates each of the workpiece 103 and the tool 101, and moves the tool 101 and the workpiece 103 relatively to machine the workpiece 103. More specifically, for example, before machining (or, from another perspective, before the tool 101 and the workpiece 103 come into contact with each other), the tool 101 is moved in the Y direction and positioned. Thereafter, while the tool 101 and the workpiece 103 are rotating, machining is performed by moving the tool 101 in the X direction and / or moving the workpiece 103 in the Z direction. To achieve the above-mentioned operations, the machine body 3 has, for example, the following configuration.

[0028] The machine body 3 has a base 7, the already-mentioned X-axis table 9X supported by the base 7, a column 11 fixed to the X-axis table 9X, the already-mentioned saddle 13 supported by the column 11, and a tool spindle 15T supported by the saddle 13. The tool spindle 15T holds a tool 101 and is rotatable around the already-mentioned tool rotation axis AT. The X-axis table 9X is capable of linear movement in the X direction on the base 7. The saddle 13 is capable of linear movement in the Y direction relative to the column 11.

[0029] The machine body 3 also has a Z-axis table 9Z supported by the base 7, and a workpiece spindle 15W supported by the Z-axis table 9Z. The workpiece spindle 15W holds a workpiece 103 and is rotatable about the workpiece rotation axis AW described above. The Z-axis table 9Z is capable of linear movement in the Z direction on the base 7.

[0030] The configuration of the mechanism (drive source, guide, etc.) for realizing the parallel movement of the movable parts (9X, 13, and 9Z) and the rotation of the main shafts (15W and 15T) may be various, for example, a known configuration or an application of a known configuration. For example, the drive source may be an electric motor, a hydraulic device, or a pneumatic device. In the case of an electric motor, for example, the main shaft may be driven by a rotary main shaft motor (electric motor). The parallel movement of the movable parts may be realized by a linear motor, or may be realized by converting the rotation of a rotary electric motor into linear motion by an appropriate mechanism (for example, a ball screw mechanism).

[0031] Also, for example, the linear guide (25X, 25Y or 25Z) that guides the movable parts (9X, 13 and 9Z) (or, from another point of view, restricts movement in directions other than the driving direction) may be a sliding guide in which the movable part and the fixed part slide, a rolling guide in which a rolling body rolls between the movable part and the fixed part, a hydrostatic guide in which air or oil is interposed between the movable part and the fixed part, or a combination of two or more of these. Similarly, the bearings of the main shafts (15W and 15T) may be sliding bearings, rolling bearings, hydrostatic bearings, or a combination of two or more of these.

[0032] In the illustrated example, two guides (17X and 17X, 17Y and 17Y, or 17Z and 17Z) extending parallel to each other in the moving direction are provided for each movable part (9X, 13, or 9Z). The entire configuration including the two guides may be regarded as one guide. Also, a guide that cannot be regarded as having two guides (i.e., can only be regarded as one guide) may be provided for each movable part. Two guides related to the X-axis and Z-axis support the movable part (9X or 9Z). Two Y-axis guides 17Y related to the Y-axis do not necessarily support the entire load of the saddle 13, but the column 11 may be expressed as supporting the saddle 13 via the Y-axis guides 17Y.

[0033] In the illustrated example, the two guides of each movable part (9X, 13, or 9Z) are configured by VV rolling guides. More specifically, for example, the X-axis guide 17X has a groove with a V-shaped cross section formed on the upper surface of the X-axis bed 19X supporting the X-axis table 9X, a protrusion with a triangular cross section formed on the lower surface of the X-axis table 9X, and a plurality of rollers (not shown) interposed between the groove and the protrusion. The Y-axis guide 17Y has a groove with a V-shaped cross section formed on the side surface of the column 11, a protrusion with a triangular cross section formed on the side surface of the saddle 13, and a plurality of rollers (not shown) interposed between the groove and the protrusion. The Z-axis guide 17Z has a groove with a V-shaped cross section formed on the upper surface of the Z-axis bed 19Z supported on a portion extending from the X-axis bed 19X to the -Z side, a protrusion with a triangular cross section formed on the lower surface of the Z-axis table 9Z, and a plurality of rollers (not shown) interposed between the groove and the protrusion.

[0034] The controller 5 includes, for example, an NC device and a driver (e.g., a servo driver), although not shown. The NC device includes, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an external storage device (e.g., a hard disk drive (HDD) or a solid state drive (SSD)), although not shown. In other words, the NC device includes a computer. The CPU executes programs stored in the ROM and / or the external storage device, thereby implementing various functional units that perform control and the like. The controller 5 may also include a logic circuit that performs only certain operations.

[0035] The controller 5 controls, for example, the rotation speed of the spindles (15W and 15T) and the speed and position of the movable parts (9X, 13 and 9Z). The position control and speed control may be, for example, a so-called fully closed loop control. That is, the detected values ​​of the position and speed of the movable parts may be fed back. However, the position control and / or speed control may be an open loop control in which no feedback is performed, or a semi-closed loop control in which the detected value of the rotation speed of the electric motor is fed back.

[0036] The machining accuracy of the processing machine 1 may be set appropriately. For example, the processing machine 1 may be capable of performing machining with sub-micrometer order accuracy (error less than 1 μm) or nanometer order accuracy (error less than 10 nm). Such machine tools have already been put into practical use by the applicant of the present application (for example, the UVM series, ULG series, and ULC series). More specifically, for example, the positioning accuracy in each axis may be 1 μm or less, 0.1 μm or less, 10 nm or less, or 1 nm or less.

[0037] (2. Scale-related configuration) (2.1. Scale) In this section 2.1, the two-dimensional scale itself will be basically explained. In other words, matters common to the X-axis sensor 25X, the Y-axis sensor 25Y, and the Z-axis sensor 25Z will be explained. The arrangement of the two-dimensional scale for each axis will be described in the next section (section 2.2).

[0038] However, for convenience, the explanation in this section will basically take the X-axis sensor 25X as an example. The following explanation may be applied to a two-dimensional scale that detects displacement in other directions. In this case, the terms in the following explanation may be replaced with other terms as appropriate. For example, when applied to the Y-axis sensor 25Y, "X" and "Y" are replaced with each other, "x" and "y" are replaced with each other, and "X-axis table 9X" is replaced with "saddle 13". When applied to the Z-axis sensor 25Z, "X" and "Z" are replaced with each other, and "x" and "z" are replaced with each other.

[0039] (2.1.1. Scales in general) 1, the X-axis sensor 25X has, for example, a scale section 27 extending in the X direction and a detection section 29 facing the scale section 27. In the scale section 27, for example, a plurality of optically or magnetically formed patterns are arranged at a certain pitch (in a higher-level concept, according to a predetermined rule) in the X direction (or in the Z direction in addition to the X direction depending on the configuration of the X-axis sensor 25X). The detection section 29 generates a signal according to the relative position with respect to each pattern. Therefore, it is possible to detect a displacement (position) by counting the number of signals (i.e., counting the number of patterns) generated in association with the relative movement of the scale section 27 and the detection section 29.

[0040] X-axis sensor 25X may be of an absolute type that can specify the position (absolute position) of detection unit 29 relative to scale unit 27 based on the pattern of scale unit 27, or may be of an incremental type that cannot specify such a position. As is well known, even in the case of an incremental scale, the absolute position can be specified by moving detection unit 29 to a predetermined position (e.g., a movement limit) relative to scale unit 27 and performing calibration.

[0041] The error (displacement in the Z direction) associated with the movement of the X-axis table 9X is naturally small compared to the movable length of the X-axis table 9X in the X direction. Therefore, in the X-axis sensor 25X, the length of the range in which the position in the Z direction can be detected may be shorter than the length of the range in which the position in the X direction can be detected. In the X-axis sensor 25X, the detection accuracy of the position in the X direction and the detection accuracy of the position in the Z direction may be equal to each other or may be different from each other. In either case, in the X-axis sensor 25X, the detection accuracy of the position in the X direction and the detection accuracy of the position in the Z direction may each be relatively high, and may be, for example, 1 μm or less, 0.1 μm or less, 10 nm or less, or 1 nm or less.

[0042] (2.1.2. Specific examples of scale composition) The two-dimensional scale may have various configurations including known configurations. An example is shown below. As described later, the X-axis sensor 25X can detect not only the displacement in the X-direction and the Z-direction but also the rotation error around the Y-axis. However, in this section 2.1.2, only the configuration related to the detection of the displacement in the X-direction and the Z-direction is described, and the detection of the rotation error is described in the next section (section 2.1.3). For convenience, the term "displacement" refers to linear displacement and does not refer to rotational displacement unless otherwise specified or unless there is a contradiction. Also, for convenience, when describing the position and shape of each part of the X-axis sensor 25X, the terms "X direction" and "Z direction" may be referred to on the assumption that there is no rotation error.

[0043] Fig. 3(a) is an enlarged view of a portion of the X-axis sensor 25X. For convenience of explanation, the orientation of the scale unit 27 and the detection unit 29 with respect to the Cartesian coordinate system XYZ may differ between Fig. 3(a) and other figures, but this is not an essential difference. In the following explanation (formula), the + and - signs may be appropriately replaced according to the actual orientation.

[0044] The scale portion 27 has, for example, an A-phase scale portion 27a and a B-phase scale portion 27b extending parallel to each other in the X direction. The A-phase scale portion 27a and the B-phase scale portion 27b have a plurality of patterns 27c formed optically or magnetically. The plurality of patterns 27c are linearly inclined with respect to the X direction. The A-phase scale portion 27a and the B-phase scale portion 27b have the same inclination angle of the plurality of patterns 27c, and the inclination directions are opposite to each other. The detection portion 29 has, for example, an A-phase detection portion 29a that detects the pattern 27c of the A-phase scale portion 27a and a B-phase detection portion 29b that detects the pattern 27c of the B-phase scale portion 27b. The plurality of patterns 27c resemble fish bones in the entire A-phase scale portion 27a and the entire B-phase scale portion 27b. Therefore, a two-dimensional scale having such a pattern may be called a fishbone-shaped two-dimensional scale.

[0045] FIG. 3(b) is a schematic enlarged view of a portion of the A-phase scale portion 27a.

[0046] A displacement dA in a direction perpendicular to the pattern 27c of the A-phase scale portion 27a is detected by counting the number of the patterns 27c detected by the A-phase detection portion 29a. The inclination angle with respect to the X-axis in the direction perpendicular to the pattern 27c is θ, the X-direction component of the displacement dA is x1, and the Z-direction component of the displacement dA is z1. In this case, the following equation is established. dA = x1 × cosθ + z1 × sinθ (1)

[0047] Meanwhile, the displacement dB (FIG. 3(a)) in a direction perpendicular to the pattern 27c of the B-phase scale portion 27b is detected by counting the pattern 27c detected by the B-phase detection portion 29b. At this time, since the inclination angle of the pattern 27c is the same in the A-phase scale portion 27a and the B-phase scale portion 27b, the inclination angle (absolute value) of the B-phase scale portion 27b in the direction perpendicular to the pattern 27c is also θ. Furthermore, if it is assumed that the detection portion 29 does not rotate around the Y-axis, the X-direction component and the Z-direction component of the displacement dB are the same as the X-direction component and the Z-direction component (x1 and z1) of the displacement dA. Therefore, the following equation is established. dB=x1×cosθ-z1×sinθ (2)

[0048] From the above equations (1) and (2), the following equation is derived. x1 = (dA + dB) / (2 × cosθ) (3) z1 = (dA-dB) / (2 × sinθ) (4) By using this principle, the two-dimensional scale in the illustrated example can detect displacement in two directions.

[0049] Examples of two-dimensional scales other than the illustrated examples include those shown in FIG. 8 of Patent Document 1 and FIG. 4 of Patent Document 2. In this two-dimensional scale, a plurality of first patterns extending parallel to the Z axis and arranged in the X direction, and a plurality of second patterns extending parallel to the X axis and arranged in the Z axis are provided. Displacement in the X direction is detected by counting the plurality of first patterns, and displacement in the Z direction is detected by counting the plurality of second patterns. In other words, this two-dimensional scale has a configuration in which normal one-dimensional linear scales are made to intersect at right angles with each other.

[0050] (2.1.3. Configuration related to detection of rotation error) The two-dimensional scales (25X, 25Y, and 25Z) according to the embodiment are configured to be capable of detecting a rotation error around an axis perpendicular to the two directions in which the displacement is detected. The detected rotation error is used, for example, for feedback control to reduce the effect of the rotation error on the relative position between the tool 101 and the workpiece 103. The configuration for detecting the rotation error is, for example, as follows.

[0051] As shown in Fig. 3(a), the X-axis sensor 25X has two A-phase detection units 29a whose positions in the X direction are different from each other. Therefore, when the detection unit 29 rotates around the Y axis with respect to the scale unit 27, the relative positions of the two in the Z direction change by an amount of movement corresponding to the amount of rotation. Therefore, the rotation error can be identified based on the two errors (displacements in the Z direction) detected by the two A-phase detection units 29a. It is apparent that two B-phase detection units 29b may be provided instead of the two A-phase detection units 29a.

[0052] More specifically, for example, the displacement dA detected by the two A-phase detection units 29a is denoted as dA' and dA'', respectively, and its Z-direction components are denoted as z1' and z1''. Since the rotation error is minute, x1 can be considered to be the same in dA' and dA''. In this case, the following equation holds, similar to equation (1). dA′=x1×cosθ+z1′×sinθ (1)′ dA″=x1×cosθ+z1″×sinθ (1)″ Subtracting equation (1)″ from equation (1)’ and rearranging, we obtain the following equation. z1′-z1″=(dA′-dA″) / sinθ (5) If the distance between the two A-phase detection units 29a is d, the rotation error α can be calculated by the following formula. α=arctan((z1′-z1″) / d) (6)

[0053] The rotation error α is calculated using two errors (z1) detected simultaneously by the two A-phase detection units 29a. "Simultaneous" here does not have to mean strictly simultaneous. For example, the detection points of the two errors may be different points in time within the same period (sampling period) in which detection is repeated or the same period (control period, described later) in which control is repeated. Furthermore, each of the two errors may be an average value of multiple sampling periods.

[0054] In the example of FIG. 3(a), when there is no rotation error, the positions in the X direction of one A-phase detector 29a and one B-phase detector 29b are the same. However, as illustrated in FIG. 4 described later, both of the positions in the X direction of the two A-phase detectors 29a may be different from the position in the X direction of the B-phase detector 29b. In the example of FIG. 4, the B-phase detector 29b is located exactly midway between the two A-phase detectors 29a in the X direction. Also, in the example of FIG. 3(a), when there is no rotation error, the positions in the Z direction of the two A-phase detectors 29a are the same. However, they may be different.

[0055] The distance d may be set appropriately. As the distance d is increased, the absolute value of z1'-z1" becomes larger relative to the absolute value of α, and thus the detection accuracy of α improves. However, the size of the detection unit 29 increases. The distance d may be set, for example, to be longer than the distance in the Z direction between the A-phase detection unit 29a and the B-phase detection unit 29b when no rotation error occurs.

[0056] When x1 or z1 is calculated by equation (3) or equation (4), either of the two displacements dA (dA′ and dA″) may be used, or the average value of the two displacements dA may be used. For example, in the example of FIG. 3(a), the displacement dA detected by the A-phase detection unit 29a closer to the B-phase detection unit 29b may be used. In the example of FIG. 4, the average value of the two displacements dA may be used.

[0057] To detect a rotation error, it is sufficient to detect the displacement (error) in the Z direction at two different positions in the X direction, and so it is naturally possible to detect it on other types of two-dimensional scales as well. For example, as described above, in a two-dimensional scale in which ordinary one-dimensional linear scales are mutually orthogonalized, two detectors for detecting displacement in the Z direction can be provided at different positions in the X direction. Then, z1' and z1" detected by the two detectors can be substituted into equation (6) (equation (5) is obviously unnecessary).

[0058] (2.2. Scale arrangement on each axis) In each movable part (9X, 13, or 9Z) shown in FIG. 1 and FIG. 2, two mutually orthogonal directions can be considered as directions perpendicular to the direction to be translated (X direction, Y direction, or Z direction). For example, for the X-axis table 9, there are two directions, the Z direction and the Y direction, that are perpendicular to the X direction. Therefore, it is meaningful to provide two two-dimensional scales in different orientations for one movable part (one axis). For example, the X-axis table 9 may be provided with a two-dimensional scale that detects displacement in the X and Z directions, and a two-dimensional scale that detects displacement in the X and Y directions.

[0059] However, in the first embodiment, only one two-dimensional scale is provided for each movable part, and the two-dimensional scale is provided to detect errors when the processing machine 1 is viewed in the Y direction. In other words, the priority of detecting errors in the Y direction is low. Specifically, as already mentioned, the X-axis sensor 25X is provided in an orientation to detect displacements in the X and Z directions. The Y-axis sensor 25Y is provided in an orientation to detect displacements in the Y and Z directions. The Z-axis sensor 25Z is provided in an orientation to detect displacements in the Z and X directions. Such an arrangement of two-dimensional scales can effectively detect errors that have a relatively large effect on processing, for example, in a processing machine that is intended to position a movable part (saddle 13) in the Y direction.

[0060] In the X-axis sensor 25X, one of the scale unit 27 and the detection unit 29 (detection unit 29 in the illustrated example) is fixed directly or indirectly to the X-axis table 9X. The other of the scale unit 27 and the detection unit 29 (scale unit 27 in the illustrated example) is fixed directly or indirectly to the X-axis bed 19X. Therefore, when the X-axis table 9X moves, the scale unit 27 and the detection unit 29 move relatively. As a result, the displacement (position) of the X-axis table 9X is detected. More specifically, for example, it is as follows.

[0061] An X-axis scale arrangement section 21X is provided on the upper surface of the base 7. A scale section 27 of the X-axis sensor 25X is provided on the upper surface of the X-axis scale arrangement section 21X, extends in the X direction, and has a width in the Z direction. A detection section 29 of the X-axis sensor 25X is supported by a support member (reference number omitted) of appropriate shape and dimensions fixed to the X-axis table 9X, and faces the scale section 27 from above. As described in the explanation of the outline of the embodiment, the X-axis sensor 25X is located on the side of the imaginary plane VP (a plane passing through the workpiece rotation axis AW and parallel to the XZ plane) with respect to the X-axis guide 17X, and more specifically, is located within the imaginary plane VP.

[0062] In the Y-axis sensor 25Y, one of the scale unit 27 and the detection unit 29 (detection unit 29 in the illustrated example) is fixed directly or indirectly to the saddle 13. The other of the scale unit 27 and the detection unit 29 (scale unit 27 in the illustrated example) is fixed directly or indirectly to the column 11. Therefore, when the saddle 13 moves, the scale unit 27 and the detection unit 29 move relatively. As a result, the displacement (position) of the saddle 13 is detected. More specifically, for example, as follows.

[0063] A Y-axis scale arrangement section 21Y is provided on the upper surface of the X-axis table 9X. A scale section 27 of the Y-axis sensor 25Y is provided on a side surface of the Y-axis scale arrangement section 21Y facing the X direction, extends in the Y direction, and has a width in the Z direction. A detection section 29 of the Y-axis sensor 25Y is supported by a support member (reference number omitted) of appropriate shape and size fixed to the saddle 13, and faces the scale section 27 in the X direction. In the illustrated example, the support member penetrates the column 11 in the Z direction. The Y-axis sensor 25Y is located on the side of a virtual plane VP (a plane passing through the tool rotation axis AT and parallel to the YZ plane) with respect to the Y-axis guide 17Y, and more specifically, is located within the virtual plane VP.

[0064] In the Z-axis sensor 25Z, one of the scale unit 27 and the detection unit 29 (detection unit 29 in the illustrated example) is fixed directly or indirectly to the Z-axis table 9Z. The other of the scale unit 27 and the detection unit 29 (scale unit 27 in the illustrated example) is fixed directly or indirectly to the Z-axis bed 19Z. Therefore, when the Z-axis table 9Z moves, the scale unit 27 and the detection unit 29 move relatively. As a result, the displacement (position) of the Z-axis table 9Z is detected. More specifically, for example, as follows.

[0065] A Z-axis scale arrangement section 21Z is provided on the upper surface of a portion where the X-axis bed 19X is extended toward the Z-axis bed 19Z. A scale section 27 of the Z-axis sensor 25Z is provided on the upper surface of the Z-axis scale arrangement section 21Z, extends in the Z direction, and has a width in the X direction. A detection section 29 of the Z-axis sensor 25Z is supported by a support member (reference number omitted) of appropriate shape and dimensions fixed to the Z-axis table 9Z, and faces the scale section 27 from above. The Z-axis sensor 25Z is located on the side of the imaginary plane VP (a plane passing through the workpiece rotation axis AW and parallel to the XZ plane) with respect to the Z-axis guide 17Z, and more specifically, is located within the imaginary plane VP.

[0066] When referring to the distance from the virtual plane VP to the two-dimensional scale (25X, 25Y or 25Z) or comparing the position of the two-dimensional scale with the position of the linear guide (17X, 17Y or 17Z) in the normal direction of the virtual plane VP, the position of the two-dimensional scale may be based on a part that directly contributes to detection. For example, the surface facing the detection unit 29 of the scale unit 27 (a surface parallel to the virtual plane VP in another respect) may be based on the position. For example, in the X-axis sensor 25X, the position of the upper surface of the scale unit 27 (however, the area facing the detection unit 29) may be based on the position.

[0067] Also, the position of the linear guide may be based on a portion that directly contributes to guiding the movable part and is located on the virtual plane VP side, so that the requirement that the two-dimensional scale be located on the virtual plane VP side of the linear guide is determined relatively strictly. For example, in the X-axis guide 17X, the upper end of the area that comes into contact with a roller (not shown) on the surface (inclined surface) of the protrusions on the lower surface of the X-axis table 9X may be based on the X-axis guide 17X.

[0068] When the two-dimensional scale is said to be located within the imaginary plane VP, it is not necessary that the reference for the position of the two-dimensional scale (e.g., the surface of the scale section 27) be strictly located within the imaginary plane VP as described above. For example, if the distance between them is 5 times or less, 2 times or less, or 1 time or less of the distance (gap) between the scale section 27 and the detection section 29, the two-dimensional scale may be considered to be located within the imaginary plane VP. The gap is, for example, 2 mm or less, or 1 mm or less.

[0069] In each axis, the detection unit 29 of the two-dimensional scale may be located near the processing point in the direction in which the movable part (9X, 13 or 9Z) should move. In other words, the detection unit 29 may be located near (for example, within) a virtual plane (not shown) that includes the processing point and is perpendicular to the direction in which the movable part should move. In other words, the detection unit 29 may be located near (for example, within) the intersection line between the perpendicular virtual plane (not shown) and the virtual plane VP. Instead of the processing point, the tip of the main shaft (15W or 15T) supported by the movable part and the position on the rotation axis of the main shaft may be used as the reference. The reference position of the detection unit 29 may be the center of a part that substantially contributes to detection. The "near" the perpendicular virtual plane (not shown) or the intersection line may be, for example, less than 1 / 2, less than 1 / 3, less than 1 / 5 or less than 1 / 10 of the distance from the virtual plane VP to the linear guide.

[0070] For example, the detection unit 29 of the X-axis sensor 25X may be arranged near a virtual plane that is perpendicular to the X direction and includes the tool rotation axis AT (illustrated example). The detection unit 29 of the Z-axis sensor 25Z may be arranged near a virtual plane that is perpendicular to the Z direction and includes the tip of the work spindle 15W, unlike the illustrated example. The detection unit 29 of the Y-axis sensor 25Y may be arranged near a virtual plane that is perpendicular to the Y direction and includes the tip of the tool spindle 15T, unlike the illustrated example. By doing so, for example, as will be understood from the explanation of the effect of yaw (section 4.2) described later, the need to convert a rotation error about an axis perpendicular to the two directions in which the two-dimensional scale detects the position into an error of the machining point in the lateral direction of the two-dimensional scale is reduced.

[0071] (2.3. Scale placement section) The position, shape, dimensions, etc. of the scale arrangement portion (21X, 21Y, and 21Z) may be set appropriately so that the two-dimensional scale (17X, 17Y, and 17Z) can be arranged at a desired position. In the illustrated example, it is as follows.

[0072] The scale placement portion is shaped like a rectangular parallelepiped. Moreover, the scale placement portion is a solid (non-hollow) metal member. In other words, the scale placement portion is integrally formed from metal. In this regard, the detailed shape may be ignored. Examples of the detailed shape include the shape of a portion for attaching the scale placement portion to the base 7 or the like, and the shape of a portion for attaching the two-dimensional scale to the scale placement portion. From another perspective, examples include a female thread, a through hole (a hole that is not a female thread) through which a bolt is inserted, or a recess into which a part of some member fits. The type of metal is arbitrary, and is, for example, cast iron.

[0073] In each axis, the scale mounting section is supported by a member (e.g., a support section supporting the fixed section) different from the member (fixed section) supporting the movable section via a linear guide. Furthermore, the scale mounting section is separated from the fixed section. Specifically, the following is true.

[0074] The X-axis scale mounting section 21X is not supported by the X-axis bed 19X, but is supported by the base 7. In addition, the X-axis scale mounting section 21X is separated from the X-axis bed 19X in the Z direction.

[0075] The Y-axis scale mounting section 21Y is supported by the X-axis table 9X, not by the column 11. In addition, the Y-axis scale mounting section 21Y is separated from the column 11 in the Z direction.

[0076] The Z-axis scale mounting section 21Z is supported by an extension of the X-axis bed 19X, rather than by the Z-axis bed 19Z. In addition, the Z-axis scale mounting section 21Z is spaced apart from the Z-axis bed 19Z in the X direction.

[0077] In each axis, the distance between the scale placement portion and the fixed portion (19X, 11, or 19Z) is arbitrary as long as they do not come into contact with each other. For example, it may be less than 1 cm or may be 1 cm or more.

[0078] Unlike the illustrated example, the scale placement section may be configured by combining a plurality of members, may have a cavity, or may be supported by a fixed section.

[0079] (3. Control System) (3.1. Multi-axis control system) (3.1.1. Overview of Control) FIG. 4 is a block diagram showing the configuration of a control system in the processing machine 1.

[0080] The left side of Fig. 4 shows a three-axis movable part (9X, 13, and 9Z), a three-axis two-dimensional scale (25X, 25Y, and 25Z), and electric motors (23X, 23Y, and 23Z) that drive the three-axis movable part. The right side of Fig. 4 shows the configuration of the controller 5.

[0081] The controller 5 has a signal processing unit 34 that processes signals from the three-axis two-dimensional scale, and a control main unit 35 that controls the three-axis electric motors based on signals from the signal processing unit 34. The signal processing unit 34 has an input processing unit (31X, 31Y, or 31Z) and two correction units (31Xx and 31Xz, 31Yy and 31Yz, or 31Zx and 31Zz) for each axis. The control main unit 35 has a control unit (33X, 33Y, or 33Z) that controls the electric motor for each axis.

[0082] The input processing unit (31X, 31Y, or 31Z) of each axis identifies the displacement in two directions and the rotation error based on the signal input from the two-dimensional scale. In each axis, each correction unit (32Xx, etc.) corrects the displacement in one of the two directions identified by the input processing unit based on the rotation error identified by the input processing unit, as described in detail later. In each axis, one of the displacements in the two directions (the displacement in the direction in which the movable part should move) is used for normal feedback control. The remaining one (the error) is used to control the other axis to counteract the effect of the error on the relative position of the tool 101 and the workpiece 103.

[0083] The signal processing unit 34, the control main unit 35, the input processing unit, the correction unit, and the control unit for each axis (33X, 33Y, or 33Z) are functional or conceptual divisions. Therefore, for example, from the viewpoint of hardware, these control units may be configured integrally or may be configured separately. Also, the control unit (33X, 33Y, or 33Z) may be considered to include a driver or not include a driver (from another viewpoint, the driver is not shown in FIG. 4).

[0084] In general, the term sensor may refer only to a transducer that converts a physical quantity into a signal, or may refer to a device that includes a transducer and a functional unit connected to the transducer. Examples of the functional unit include a driver that supplies power to the transducer and a calculation unit that processes signals from the transducer. In this embodiment, the two-dimensional scale may be either. As described above, the division shown in the figure is functional or conceptual, so that at the distribution stage of the two-dimensional scale, a part of the signal processing unit 34 (for example, the input processing unit (31X, 31Y, or 31Z)) may be part of the two-dimensional scale.

[0085] (3.1.2. Signal Processing) The meanings of the symbols attached to the signal paths from the input processing units (31X, 31Y, or 31Z) to the correction units (32Xx, etc.) are as follows. For convenience, the saddle 13 will be referred to as the Y-axis table below. Symbols not shown in FIG. 4 but shown in FIG. 8 are also shown. XPosX: "Displacement" in the "X" direction of the "X" axis table XPosY: "Displacement" (error) of the "Y" direction of the "X" axis table XPosZ: "Displacement" (error) of the "X" axis table in the "Z" direction YPosX: "Displacement" (error) of the "X" direction of the "Y" axis table YPosY: Displacement in the Y direction of the Y-axis table YPosZ: Displacement (error) of the Y-axis table in the Z direction ZPosX: "Displacement" (error) of the "Z" axis table in the "X" direction ZPosY: Displacement (error) of the Z-axis table in the Y-direction ZPosZ: Displacement in the Z direction of the Z-axis table XRotX: "Rotation error" around the "X" axis of the "X" axis table XRotY: "Rotation error" around the "Y" axis of the "X" axis table XRotZ: "Rotation error" around the "Z" axis of the "X" axis table YRotX: "Rotation error" around the "X" axis of the "Y" axis table YRotY: "Rotation error" around the "Y" axis of the "Y" axis table YRotZ: "Rotation error" around the "Z" axis of the "Y" axis table ZRotX: "Rotation error" around the "X" axis of the "Z" axis table ZRotY: "Rotation error" around the "Y" axis of the "Z" axis table ZRotZ: "Rotation error" around the "Z" axis of the "Z" axis table

[0086] The operations of the input processing unit and the correction unit are as described above, but to be sure, they will be described with reference numbers assigned to each axis.

[0087] The X-axis input processing unit 31X determines the X-direction displacement (XPosX) and Z-direction displacement (XPosZ) of the X-axis table 9X and the rotation error around the Y-axis (XRotY) based on a signal from the X-axis sensor 25X. The correction unit 32Xx corrects XPosX based on XRotY. The correction unit 32Xz corrects XPosZ based on XRotY.

[0088] The Y-axis input processing unit 31Y determines the displacement (YPosY) of the saddle 13 in the Y direction and the displacement (YPosZ) in the Z direction, and the rotation error (YRotX) around the X axis, based on a signal from the Y-axis sensor 25Y. The correction unit 32Yy corrects YPosY based on YRotX. The correction unit 32Yz corrects YPosZ based on YRotX.

[0089] The Z-axis input processing unit 31Z determines the Z-direction displacement (ZPosZ) and X-direction displacement (ZPosX) of the Z-axis table 9Z, and the rotation error around the Y-axis (ZRotY) based on a signal from the Z-axis sensor 25Z. The correction unit 32Zz corrects ZPosZ based on ZRotY. The correction unit 32Zx corrects ZPosx based on ZRotY.

[0090] For each axis, for example, three signals generated by three detectors (29a, 29b, and 29a) are input from the two-dimensional scale to the input processing unit (31X, 31Y, or 31Z). Each signal is, for example, a pulse signal in which one pattern 27c that passes directly under the detector (29a, 29b, or 29a) corresponds to one waveform (pulse wave). The pulse wave is, for example, a sine wave, a square wave, a triangular wave, or a sawtooth wave.

[0091] The input processing unit for each axis (31X, 31Y, or 31Z) performs, for example, a calculation equivalent to the formulas (3) to (6) based on the three input signals to identify the displacements and rotation errors in the two directions. A specific example of the correction by the correction unit will be described later (Section 4).

[0092] (3.1.3. Feedback Control) As described above, in each axis, the detected displacement in the direction in which the movable part (9X, 13, or 9Z) should move is used for feedback control (normal feedback control) in that direction. Specifically, this is as follows.

[0093] The displacement (signal SXx) of the X-axis table 9X in the X direction calculated by the correction unit 32Xx is used by the X-axis control unit 33X for full-closed loop control of the X-axis motor 23X that drives the X-axis table 9X. The displacement (signal SYy) of the saddle 13 in the Y direction calculated by the correction unit 32Yy is used by the Y-axis control unit 33Y for full-closed loop control of the Y-axis motor 23Y that drives the saddle 13. The displacement (signal SZz) of the Z-axis table 9Z in the Z direction calculated by the correction unit 32Zz is used by the Z-axis control unit 33Z for full-closed loop control of the Z-axis motor 23Z that drives the Z-axis table 9Z.

[0094] (3.1.4. Error Compensation) As described above, in each axis, the detected displacement (detection error) in the direction perpendicular to the direction in which the movable part should move is used for control to reduce the error in the relative position of the tool 101 and the workpiece 103 caused by the error. Specifically, this is as follows.

[0095] The error in the Z direction of the X-axis table 9X calculated by the correction unit 32Xz (signal SXz) is added by an adder 36Z to the displacement in the Z direction calculated by the correction unit 32Zz (signal SZz), and the result is input to the Z-axis control unit 33Z. For convenience, it is expressed as "addition", but a calculation is performed so that the original control amount of the Z-axis table 9Z (the movement amount based on the signal SZz) is corrected in the same direction and by the same amount as the error in the Z direction of the X-axis table 9X (the actual calculation in the control unit may be subtraction; the same applies below).

[0096] The error (signal SYz) in the Z direction of the saddle 13 calculated by the correction unit 32Yz is added to the displacement (signal SZz) in the Z direction calculated by the correction unit 32Zz by the adder 36Z, and the result is input to the Z-axis control unit 33Z. For convenience, it is expressed as "addition", but the calculation is performed so that the original control amount of the Z-axis table 9Z (from another point of view, the movement amount based on the signal SZz) is corrected in the same direction and by the same amount as the error in the Z direction of the saddle 13.

[0097] The error in the X direction of Z-axis table 9Z calculated by correction unit 32Zx (signal SZx) is added by addition unit 36X to the displacement in the X direction (signal SXx) calculated by correction unit 32Xx, and the result is input to X-axis control unit 33X. For convenience, the expression "addition" is used, but, for example, a calculation is performed so that the original control amount of X-axis table 9X (from another point of view, the movement amount based on signal SXx) is corrected in the same direction and by the same amount as the error in the Z direction of Z-axis table 9Z.

[0098] In the control section (33X, 33Y or 33Z) of each axis, acquisition of a position based on a signal from the signal processing section 34 and control of the electric motor (23X, 23Y or 23Z) based on the acquired position are repeatedly performed at a predetermined control period. The control periods in the control sections (33X, 33Y and 33Z) of the three axes are, for example, the same as each other (it is possible to make them different), and are synchronized.

[0099] The input processing unit (31X, 31Y, or 31Z) of each axis acquires a signal from the two-dimensional scale (25X, 25Y, or 25Z) at a predetermined sampling period, for example, and calculates the displacement and rotation error (detection value) in two directions. The sampling periods in the input processing units (31X, 31Y, and 31Z) of the three axes are, for example, the same as each other (it is possible to make them different), and are synchronized.

[0100] The sampling period may be the same as or shorter than the control period, for example. In either case, in the control for each control period, raw (unprocessed) detection values ​​or detection values ​​that have been subjected to some processing may be used.

[0101] For example, the displacement (XPosX, YPosY or ZPosZ) in the direction (first direction) in which the movable part (9X, 13 or 9Z) of each axis should move, used by the control part (33X, 33Y or 33Z) of each axis, may be the latest raw detection value. This can reduce the possibility of a control delay occurring with respect to the actual position in the first direction, for example.

[0102] On the other hand, the error (XPosZ, YPosZ, ZPosX, XRotY, YRotX, or ZRotY) used by the control unit (33X, 33Y, or 33Z) of each axis may be set to the average value of a predetermined number (e.g., 10) of detection values ​​including the most recent detection value. This reduces the likelihood of over-responding to a specific error, for example.

[0103] Specific values ​​of the sampling period and the control period are not particularly limited and may be appropriately set according to the accuracy required for the processing machine 1. For example, the sampling period and / or the control period may be 0.02 sec or less, 0.01 sec or less, or 0.005 sec or less.

[0104] (3.2. Control system for each axis) 5 is a block diagram showing an example of the configuration of a control system for each axis, in which the configuration related to the control for driving the Z-axis table 9Z is taken as an example.

[0105] As described with reference to Fig. 4, in controlling the driving of the Z-axis table 9Z, not only the detection value of the Z-axis sensor 25Z but also the detection values ​​of the X-axis sensor 25X and the Y-axis sensor 25Y may be used. Here, first, the control based on the detection value of the Z-axis sensor 25Z will be described. Then, the manner in which the detection values ​​of the X-axis sensor 25X and the Y-axis sensor 25Y are used will be described. For convenience, in describing the control based on the detection value of the Z-axis sensor 25Z, the presence of the adder 36Z, the X-axis sensor 25X, and the Y-axis sensor 25Y may be ignored.

[0106] (3.2.1. Z-axis control based on Z-axis sensor) The control for driving the Z-axis table 9Z based on the detection value (signal SZz) of the Z-axis sensor 25Z may be the same as general control in a machine tool, for example. For example, it is as follows. Just to be sure, as described with reference to FIG. 4, the signal SZz is corrected by the correction unit 32Zz. Therefore, even if the control procedure described below is general, the control as a whole is substantially different from the general one.

[0107] The NC program 107 includes command information regarding the drive of each axis. For example, the NC program 107 includes command information regarding the movement of the X-axis table 9X, the Z-axis table 9Z, and the saddle 13. The command information regarding the movement includes, for example, information regarding a plurality of positions on a movement trajectory and speeds between the plurality of positions.

[0108] The interpretation unit 39 of the controller 5 reads and interprets the NC program 107. As a result, for example, for each of the table (9X and 9Z) and the saddle 13, information on the multiple positions that are sequentially passed through and the speed between the multiple positions is obtained.

[0109] The interpolation unit 41 of the controller 5 calculates a target position and the like for each predetermined control cycle based on the information acquired by the interpretation unit 39. For example, based on two positions that are passed through in sequence and the speed between the two positions, a plurality of target positions to be reached in sequence for each control cycle are set between the two positions. The interpolation unit 41 calculates and outputs the target position and the like for each control cycle for each axis. In FIG. 5, the target position for each control cycle of the Z-axis table 9Z is output to the addition unit 43 of the controller 5.

[0110] In addition to the target position, the detected position (signal SZz) in the Z direction of Z-axis table 9Z detected by Z-axis sensor 25Z is input to adder 43. Adder 43 calculates the deviation between the target position and the detected position. The calculated deviation (target movement amount per control cycle) is input to position control unit 45 of controller 5.

[0111] Position control unit 45 multiplies the input deviation by a predetermined gain to calculate a target speed for each control cycle, and outputs the result to adder 47 of controller 5. In addition to the target speed, the detected speed in the Z direction of Z-axis table 9Z is input to adder 47. The detected speed is calculated by differentiating the detected position in the Z direction detected by Z-axis sensor 25Z by differentiating unit 55. Adder 47 calculates the deviation between the target speed and the detected position, and outputs the result to speed control unit 49 of controller 5.

[0112] The speed control unit 49 multiplies the input deviation by a predetermined gain to calculate a target current (target torque) for each control cycle, and outputs the result to an adder 51 of the controller 5. The adder 51 calculates the deviation between the input target current for each control cycle and a detected current from a current detection unit (not shown), and outputs the result to a current control unit 53 of the controller 5. The current control unit 53 supplies power according to the input deviation to the Z-axis motor 23Z.

[0113] (3.2.2. Controlling the Z-axis based on sensors of other axes) Adder 36Z, also shown in Fig. 4, is located on the path from Z-axis sensor 25Z to adder 43 shown in Fig. 5. Therefore, the detected position of Z-axis table 9Z input to adder 43 is corrected by adder 36Z.

[0114] Specifically, the position error in the Z direction of the X-axis table 9X (signal SXz) is subtracted from the detected position of the Z-axis table 9Z, and the position error in the Z direction of the saddle 13 (signal SYz) is subtracted. From another perspective, it can be considered that the position errors (signals SXz and SYz) are added to the deviation calculated by the adder 43 based only on the detected position (signal SZz) of the Z-axis table 9Z.

[0115] As a result, for example, the position of the Z-axis table 9Z is controlled so that the movement of the Z-axis table 9Z is increased by the same amount in the same direction as the position error (signals SXz and SYz). This cancels out the influence of the position errors of the other axes on the relative positions of the tool 101 and the workpiece 103 by the movement of the Z-axis table 9Z.

[0116] In addition, adder 36Z is located just before the path from Z-axis sensor 25Z branches off to differentiator 55. That is, the detected position of Z-axis table 9Z input to differentiator 55 is corrected by adder 36Z, and therefore the detected speed of Z-axis table 9Z input to adder 47 is indirectly corrected by adder 36Z.

[0117] Specifically, the detected speed input to the adder 47 is the detected speed of the Z-axis table 9Z minus the Z-direction speed error of the X-axis table 9X and the Z-direction speed error of the saddle 13. From another perspective, it can be considered that the above-mentioned speed error is added to the deviation calculated by the adder 47 based only on the detected speed of the Z-axis table 9Z.

[0118] As a result, for example, the speed of the Z-axis table 9Z is controlled so as to increase in the same direction and by the same amount as the above-mentioned speed error (signals SXz and SYz), thereby canceling the effect of the speed errors of the other axes on the relative speed between the tool 101 and the workpiece 103 by the movement of the Z-axis table 9Z.

[0119] The Z-axis table 9Z holds one of the tool 101 and the workpiece 103 (the workpiece 103 in FIG. 1), and the X-axis table 9X (or the saddle 13) holds the other of the tool 101 and the workpiece 103 (the tool 101 in FIG. 1). For this reason, the error of the X-axis table 9X (or the saddle 13) is subtracted from the displacement of the Z-axis table 9Z as described above. Unlike the above, in a mode in which two movable parts both hold the tool 101 or both hold the workpiece 103, the error of one movable part may be added (in the narrower sense excluding subtraction) to the displacement of the other movable part, in contrast to the above. In other words, the movable part may be controlled to move in the opposite direction to the error by the same amount as the error of the other axis.

[0120] For example, in a second embodiment described later, the X-axis sensor 225X also detects an error in the Y direction of the X-axis table 9X (XPosY in FIG. 8). This error may be added (in the narrow sense) to the displacement in the Y direction of the saddle 13 detected by the Y-axis sensor 225Y (YPosY in FIG. 8). This cancels out the effect of the error on the relative position between the tool 101 and the workpiece 103.

[0121] Note that the above explanation is based on the concept of applying the positive and negative of the Cartesian coordinate system XYZ shown in Fig. 1 to control as is. Therefore, for example, in the actual calculation in the controller 5, the addition and subtraction may be reversed from that explained above.

[0122] (3.2.3. Supplement) In the above explanation, the control related to the movement of the Z-axis table 9Z has been described, but the above explanation may be appropriately applied to the control related to the movement of the movable parts of other axes (in this embodiment, the X-axis table 9X and the saddle 13). It is clear that the explanation in Section 3.2.1 can be applied to the movable parts of other axes. In addition, the explanation in Section 3.2.2 may be appropriately applied depending on the configuration of the entire control system (FIG. 4 and FIG. 8 described later, etc.).

[0123] For example, as can be seen from Fig. 4, in the first embodiment, the detection value of the Y-axis sensor 25Y is not used in the control related to the X-axis table 9X. Therefore, when the explanation in section 3.2.2 is used in the explanation of the X-axis table 9X in the first embodiment, the explanation related to the Y-axis sensor 25Y is deleted, and the words X and Z are replaced alternately. Also, in the first embodiment, the control related to the saddle 13 does not use the detection values ​​of the sensors of the other axes. Therefore, it is not necessary to use the explanation in section 3.2.2 in the explanation of the saddle 13.

[0124] The configurations shown in Figures 4 and 5 are merely examples and may be modified as appropriate. For example, although not specifically shown, in Figure 5, feedforward control may be added. An acceleration loop may be inserted instead of the current loop. When a rotation sensor (e.g., an encoder or resolver) is provided to detect the rotation of the electric motor (23Z, etc.), speed control may be performed based on the detection value of the rotation sensor. In the feedforward and acceleration loops, errors of other axes (X-axis and Y-axis in Figure 5) may be used.

[0125] 5, the velocity error of another axis (e.g., the X-axis) is incorporated into the control of the Z-axis by adding together the displacement error of the other axis and the displacement of the Z-axis and differentiating them together. However, the displacement error of the other axis may be differentiated separately from the displacement of the Z-axis to obtain the velocity error, and then the velocity error of the other axis and the velocity error of the Z-axis may be added together.

[0126] 5, the displacement errors of the other axes are input to adder 43 via adder 36Z. However, instead of being input to adder 43, the errors may be input to interpolator 41 and used to calculate the target position for each control cycle. Similarly, the errors in the speeds of the other axes may not be input to adder 47 via adder 36Z, but may be calculated separately from the Z-axis speed as described above and used to calculate the target speed by position control unit 45.

[0127] 5, the interpretation unit 39 to the current control unit 53 (including the differentiation unit 55) correspond to the control main body unit 35 in FIG. 4. The position control unit 45 to the current control unit 53 (including the differentiation unit 55) correspond to the Z-axis control unit 33Z.

[0128] (4. How to calculate the effect of rotation error) When the movable part (9X, 13 or 9Z) generates a rotation error, the rotation error affects the relative position between the tool 101 and the workpiece 103 (from another point of view, the machining point). The correction unit (32Xx, 32Xz, 32Yy, 32Yz, 32Zz or 32Zx) shown in Fig. 4 converts, for example, the rotation error of the movable part into an error in the relative position between the tool 101 and the workpiece 103 and adds it to the displacement (in a broad sense). Any suitable method for calculating the conversion may be used. An example is shown below.

[0129] Rotation around an axis parallel to the direction in which the movable part (9X, 13 or 9Z) should move is called roll. For example, for the Z-axis table 9Z, roll is rotation around the Z-axis. Rotation around an axis parallel to the direction in which the movable part is supported by the linear guide is called yaw. For example, for the Z-axis table 9Z, yaw is rotation around the Y-axis. Rotation around an axis perpendicular to the above two axes is called pitch. For example, for the Z-axis table 9Z, pitch is rotation around the X-axis.

[0130] In the first embodiment, roll is not detected for any axis. Moreover, in the first embodiment, roll is not converted into an error in the relative position between the tool 101 and the workpiece 103. However, the explanation regarding roll is useful for understanding the effect of bringing the position of the two-dimensional scale closer to the virtual plane VP, and is also useful for understanding the second embodiment described later.

[0131] In the following description, the Z-axis table 9Z will be mainly used as an example. However, it is clear that the following description can be applied to other axes. Also, in the following description, for the sake of convenience, positive and negative values ​​may not be strictly considered.

[0132] (4.1. Role Influence) 6 is a schematic diagram for explaining the influence that the roll of the Z-axis table 9Z has on the position of the workpiece rotation axis AW (or, from another point of view, the relative position between the tool 101 and the workpiece 103). The position of the workpiece rotation axis AW may be regarded as the position of the processing point when viewed in the Z direction. Here, it is assumed that, of the two Z-axis guides 17Z, the Z-axis guide 17Z on the -X side serves as the center of rotation of the roll.

[0133] The positions, dimensions, etc. indicated by the symbols in FIG. 6 are as follows: Cr: Center of rotation of the roll (roll center) Lr: Distance in the X direction from the center of the roll to the workpiece rotation axis AW hr: Distance in the Y direction from the center of the roll to the workpiece rotation axis AW θr: The angle between the line connecting the roll center and the workpiece rotation axis AW and the Y axis rr: Distance from the center of the roll to the workpiece rotation axis AW (rotation radius) αr: Change in angle caused by roll (rotation error) dLr: Displacement (error) in the X direction caused by the roll dhr: Displacement (error) in the Y direction caused by the roll

[0134] When the meanings of the symbols are defined as above, the following formula holds: dLr=rr×sin(θr+αr)-rr×sin(θr) =rr{sin(θr+αr)-rr×sin(θr)} =rr{sin(θr)cos(αr)+cos(θr)sin(αr)-sin(θr)}

[0135] Here, since αr is infinitesimal, it can be approximated as follows: cos(αr) = 1 sin(αr) = αr

[0136] By substituting the above approximation formula into the calculation formula for dLr, the following formula is obtained. dLr≒rr×{sin(θr)+cos(θr)×αr-sin(θr)} =rr × αr × cos(θr) =rr×αr×hr / rr = αr × hr That is, dLr ≒ αr × hr

[0137] Similarly, dhr can be calculated. Specifically, the following formula is first established. dhr=rr×cos(θr)-rr×sin(θr+αr) =rr{cos(θr)-sin(θr+αr)} =rr{cos(θr)-cos(θr)cos(αr)+sin(θr)sin(αr)}

[0138] By substituting the above-mentioned approximation formula into the above formula, the following formula is obtained. dhr≒rr{cos(θr)-cos(θr)+sin(θr)×αr} =rr × αr × sin(θr) =rr×αr×Lr / rr =αr×Lr That is, dhr ≒ αr × Lr

[0139] The formula dLr ≒ αr × hr indicates that the value of dLr is determined by αr and hr, and does not depend on Lr and θr. That is, the value of dLr is the same at any position in the virtual plane VP including the workpiece rotation axis AW. Therefore, when the Z-axis sensor 25Z is located in the virtual plane VP, the Z-axis sensor 25Z can detect a deviation including the X-direction error dLr in the workpiece rotation axis AW caused by the rotation error αr due to the roll. Even if the Z-axis sensor 25Z is not located in the virtual plane VP, the closer the Z-axis sensor 25Z is to the virtual plane VP, the more the error dLr is reflected in the X-direction error detected by the Z-axis sensor 25Z. That is, the accuracy of error detection by the Z-axis sensor 25Z is substantially improved.

[0140] As can be understood from the above explanation, the effect is achieved as long as the roll center Cr is located at the same height as the Z-axis guide 17Z. In addition, in an embodiment in which two Z-axis guides 17Z are provided, as in this embodiment, the roll center Cr is highly likely to be located at one of the Z-axis guides 17Z. Therefore, for example, for convenience of explanation, the Z-axis guide 17Z on the -X side is assumed to be the roll center Cr, but the above formula is applicable in many cases, and the above effect is achieved in many cases.

[0141] Unlike the first embodiment, in an aspect where the roll is detected (for example, the second embodiment), the rotation error in the roll may be converted to a displacement error in the X direction by the formula dLr=αr×hr, and added to the displacement error in the X direction detected by the Z-axis sensor 25Z. However, the distance in the Y direction between the workpiece rotation axis AW (machining point) and the Z-axis sensor 25Z (0 in the example of FIG. 6) is used as hr. As a result, the part of the error that the rotation error αr affects on the displacement of the workpiece rotation axis AW in the X direction that is not detected by the Z-axis sensor 25Z is calculated as dLr.

[0142] As can be seen from the above, in this embodiment, the distance in the Y direction between the workpiece rotation axis AW and the Z-axis sensor 25Z is 0, so even if a roll is detected, dLr is 0 when the above distance is hr. In other words, the dLr of the roll does not need to be calculated. From this perspective, the effect of positioning the two-dimensional scale within the virtual plane VP can be explained.

[0143] Similarly, in an embodiment where a roll is detected (for example, the second embodiment), the rotation error in the roll may be converted to a displacement error in the Y direction by the formula dhr=αr×Lr, and added to the displacement error in the Y direction detected by the Z-axis auxiliary scale 26Z (FIG. 8) described later. However, the distance in the X direction between the workpiece rotation axis AW (machining point) and the Z-axis auxiliary scale 26Z is used as Lr. As a result, the portion of the error that the rotation error αr affects on the displacement of the workpiece rotation axis AW in the Y direction, which is not detected by the Z-axis auxiliary scale 26Z, is calculated as dhr.

[0144] (4.2. Yaw effect) Fig. 7 is a schematic diagram for explaining the influence of the yaw of the Z-axis table 9Z on the position of the tip of the workpiece spindle 15W (from another point of view, the machining point). For convenience, in Fig. 7, the symbol for the machining point Pp is attached to the workpiece rotation axis AW and the tip of the workpiece spindle 15W. In the actual processing machine 1, too, the tip position of the workpiece spindle 15W may be used as the position of the machining point Pp for calculation.

[0145] The positions, dimensions, etc. indicated by the symbols in FIG. Cy: Yaw rotation center (yaw center) Ly: Distance in the X direction from the yaw center to the processing point wy: ​​Z-direction distance from the yaw center to the processing point θy: The angle between the line connecting the yaw center and the processing point and the Z axis ry: Distance from the yaw center to the processing point (radius of rotation) αy: Change in angle caused by yaw (rotation error) dLy: Displacement (error) in the X direction caused by yaw dwy: Displacement in the Z direction caused by yaw (error)

[0146] The directions of the errors dwy and dLy caused by the yaw rotation error αy are both directions in which the displacement is detected by the Z-axis sensor 25Z. As described above, the Z-axis table 9Z and the X-axis table 9X are controlled based on the displacement detected by the Z-axis sensor 25Z. Therefore, regardless of the position of the yaw rotation center in the absolute coordinate system, in the control, the position of the Z-axis sensor 25Z is regarded as the yaw rotation center, and wy and dLy caused by αy may be calculated and added to the displacement detected by the Z-axis sensor 25Z.

[0147] When each symbol is defined as above, the following formula can be derived. Note that since it can be derived in the same way as dLr and dhr, the derivation process of the following formula will be omitted. dLy ≒ αy × wr dwy≒αy×Ly

[0148] 4 may calculate the correction amount of ZPozX based on ZRotY (=αy) by dLy = αy × wr. Also, the correction unit 32Zz may calculate the correction amount of ZPozZ based on ZRotY (=αy) by dwy = αy × Ly.

[0149] (4.3. Effect of pitch) In the first embodiment, a rotation error related to the pitch is detected with respect to the saddle 13 (Y axis). It is clear that the explanation of the yaw can be applied to the pitch. Therefore, an explanation of the equation for converting the rotation error related to the pitch into the displacement in two directions perpendicular to the rotation axis of the pitch will be omitted.

[0150] (5. Processing System) 1, the processing machine 1 may be connected to the diagnostic device 93 by using a technology such as OpenCNC (computerized numerical control). From another viewpoint, the processing machine 1 and the diagnostic device 93 may constitute a processing system 91.

[0151] The diagnostic device 93 may be configured to include, for example, a computer (not shown). Although not particularly shown, the computer is configured to include a CPU, a ROM, a RAM, and an external storage device, and various functional units are constructed by the CPU executing a program stored in the ROM and / or the external storage device.

[0152] The diagnostic device 93 (functional unit) acquires information related to machining, for example, from the controller 5 of the processing machine 1. The information includes, for example, information on errors detected by various two-dimensional scales (25X, 25Y, and 25Z). The error information may be raw information or information that has been subjected to some kind of processing. Then, the diagnostic device 93 performs processing based on the acquired information.

[0153] An example of the process based on the acquired information is displaying an image based on the acquired information. For example, the diagnostic device 93 has a display device 93a. The display device 93a is capable of displaying any image, and is configured with a liquid crystal display or an organic EL display. The diagnostic device 93 changes the image displayed on the display device 93a according to the acquired information.

[0154] An example of an image displayed by the diagnostic device 93 is one that shows the error itself, such as a graph with the horizontal axis representing the position in the direction in which each movable part (9X, 13, or 9Z) should move and the vertical axis representing the error. In addition, the image may be a predetermined warning image that is displayed when the obtained error (straightness) is large.

[0155] In addition to the above, the process executed by the diagnostic device 93 may include, for example, sending a control command to the controller 5 according to the error (straightness). For example, the diagnostic device 93 may send a signal to the controller 5 to stop the machining cycle when the error is large.

[0156] The diagnostic device 93 may be adjacent to the controller 5 and connected by a cable, or may be located away from the controller 5 (machine 1) and perform wireless and / or wired communication with the controller 5. In the latter case, the Internet and / or a telephone network may be interposed between the controller 5 and the diagnostic device 93. When the diagnostic device 93 is adjacent to the controller 5, the diagnostic device 93 may be regarded as a part of the machine 1. The diagnostic device 93 may also be included in the controller 5.

[0157] (6. Summary of the First Embodiment) Below, the features of the processing machine 1 will be extracted and their effects will be described. In the following description, for convenience, the Z-axis table 9Z among the movable parts (9X, 13, and 9Z) will be taken as an example of the first movable part in which an error is detected by the two-dimensional scale. The same applies to the summary of the second embodiment described later. Of course, the same can be said when the other movable parts (9X or 13) are taken as examples.

[0158] The processing machine 1 has a first movable part (Z-axis table 9Z), a linear guide (Z-axis guide 17Z), a two-dimensional scale (Z-axis sensor 25Z), and a spindle (work spindle 15W). The Z-axis table 9Z supports a work 103 or a tool 101 (work 103 in the example of FIG. 1). The Z-axis guide 17Z guides the Z-axis table 9Z in a first direction (Z direction). The Z-axis sensor 25Z outputs a signal according to a first displacement (ZPosZ) of the Z-axis table 9Z in the Z direction and a first error (ZPosX) which is a displacement of the Z-axis table 9Z in a second direction (X direction) perpendicular to the Z direction. The work spindle 15W has a fixed positional relationship with the Z-axis guide 17Z in a third direction (Y direction) perpendicular to the Z direction and the X direction (from another point of view, it is immovable in the Y direction with respect to the Z-axis guide 17Z). Furthermore, the workpiece spindle 15W rotates the workpiece 103 or the tool 101 (the workpiece 103 in the example of FIG. 1) around a first rotation axis (workpiece rotation axis AW) parallel to the Z direction or the X direction. When a virtual plane VP is assumed to include the workpiece rotation axis AW and to be parallel to the X direction and the Z direction, the distance from the virtual plane VP to the Z-axis sensor 25Z (0 in FIG. 6) is less than 1 / 3 of the distance hr from the virtual plane VP to the Z-axis guide 17Z.

[0159] 6, this makes it easier to include the error dLr in the X direction related to the relative position between the tool 101 and the workpiece 103 caused by the rotation error αr related to the roll in the error in the X direction detected by the Z-axis sensor 25Z. As a result, the detection accuracy is substantially improved. Furthermore, by controlling the processing machine 1 based on the detection result with substantially improved accuracy, the processing accuracy is improved and the product quality is improved.

[0160] The two-dimensional scale (Z-axis sensor 25Z) may be located within the imaginary plane VP. In this case, for example, the above-mentioned effects are likely to be improved.

[0161] The processing machine 1 may have a support section (an extension of the X-axis bed 19X to the -Z side), a fixed section (Z-axis bed 19Z), and a scale arrangement section (Z-axis scale arrangement section 21Z). The X-axis bed 19X may have a first surface (upper surface) facing the imaginary plane VP. The Z-axis bed 19Z may be supported on the upper surface of the X-axis bed 19X and may support a linear guide (Z-axis guide 17Z) and a first movable section (Z-axis table 9Z). The Z-axis scale arrangement section 21Z may be supported on the upper surface of the X-axis bed 19X and may be separated from the Z-axis bed 19Z. The two-dimensional scale (Z-axis sensor 25Z) may have a scale section 27 and a detection section 29. The scale section 27 of the Z-axis sensor 25Z may be fixed to the Z-axis scale arrangement section 21Z. In Z-axis sensor 25Z, detection unit 29 may be fixed to Z-axis table 9Z and may output a signal in response to relative movement with scale unit 27. Z-axis scale arrangement unit 21Z may have a height that exceeds the position of Z-axis guide 17Z from the upper surface of X-axis bed 19X toward imaginary plane VP.

[0162] In this case, for example, the Z-axis sensor 25Z can be brought closer to the virtual plane VP. As a result, the effect of improving the detection accuracy described above is achieved. Also, the scale portion 27 of the Z-axis sensor 25Z is not disposed on the Z-axis bed 19Z (such an embodiment may also be included in the technology related to the present disclosure), but is disposed on the Z-axis scale disposing portion 21Z away from the Z-axis bed 19Z. As a result, for example, when the Z-axis bed 19Z is deformed in conjunction with the movement of the Z-axis table 9Z, the likelihood that the scale portion 27 of the Z-axis sensor 25Z will be deformed is reduced. From this viewpoint as well, the detection accuracy is improved.

[0163] The scale arrangement portion (Z-axis scale arrangement portion 21Z) may be a solid metal member. In this case, for example, the Z-axis scale arrangement portion 21Z is less likely to deform due to external stress, thereby improving the above-mentioned effects.

[0164] The processing machine 1 may further include a second movable unit (X-axis table 9X), a second drive unit (X-axis motor 23X), and a controller 5. The X-axis table 9X may support the workpiece 103 or the tool 101 (the tool 101 in the example of FIG. 1). The X-axis motor 23X may drive the X-axis table 9X in a second direction (X direction). The controller 5 may control the X-axis motor 23X. Furthermore, based on a speed error in the X direction detected by the two-dimensional scale (Z-axis sensor 25Z), the controller 5 may control the X-axis motor 23X so as to reduce an error in the relative speed in the X direction of the workpiece 103 and the tool 101 caused by the speed error.

[0165] In this case, the error in the "speed" of the Z-axis table 9Z in the X direction is compensated for by moving the X-axis table 9X in the X direction. This improves the accuracy of state control. That is, an effect different from the improvement in the accuracy of position control in the case where the error in the "displacement" of the Z-axis table 9Z in the X direction is compensated for by moving the X-axis table 9X in the X direction is achieved. As a result, for example, straightness is improved. From another perspective, for example, the probability of overshooting and / or undershooting occurring with respect to a target value of the relative position of the tool 101 with respect to the workpiece 103 is reduced.

[0166] The processing machine 1 may further include a first drive unit (Z-axis motor 23Z) that drives the first movable unit (Z-axis table 9Z) in a first direction (Z direction) and a controller 5 that controls the Z-axis motor 23Z. The two-dimensional scale (Z-axis sensor 25Z) may simultaneously detect two first errors (X-direction errors of the Z-axis table 9Z) at different positions in the Z direction. The controller 5 may control the Z-axis motor 23Z so as to reduce an error in the relative position in the Z direction between the workpiece 103 and the tool 101 (dwy in FIG. 7) caused by the rotation error (ZRotY in FIG. 4, αy in FIG. 7) based on a rotation error about an axis parallel to the third direction (Y direction) specified from the two first errors by translating the Z-axis table 9Z.

[0167] In this case, for example, a two-dimensional scale can be used to easily detect the rotation error. Also, the rotation error can be converted into a displacement error in the direction in which the Z-axis table 9Z should move, and compensated for by controlling the Z-axis motor 23Z. In other words, instead of reducing the rotation error itself, the linear error caused by the rotation error is compensated for. Therefore, for example, swell in the moving direction of the Z-axis table 9Z can be reduced with a relatively simple configuration.

[0168] The processing machine 1 may further have a second movable unit (X-axis table 9X), a second drive unit (X-axis motor 23X), and a controller 5. The X-axis table 9X may support a workpiece 103 or a tool 101 (tool 101 in the example of FIG. 1). The X-axis motor 23X may drive the X-axis table 9X in a second direction (X direction). The controller 5 may control the X-axis motor 23X. The two-dimensional scale (Z-axis sensor 25Z) may simultaneously detect two first errors (X-direction errors of the Z-axis table 9Z) at different positions in the first direction (Z direction). The controller 5 may control the X-axis motor 23X so as to reduce the error in the relative position (dLy in FIG. 7) between the workpiece 103 and the tool 101 in the second direction (X direction) caused by the rotation error (ZRotY in FIG. 4, αy in FIG. 7) by translating the X-axis table 9X, based on the rotation error (ZRotY in FIG. 4, αy in FIG. 7) about the axis parallel to the third direction (Y direction) identified from the above two first errors.

[0169] In this case, for example, a two-dimensional scale can be used to easily detect the rotation error. Also, the rotation error can be converted into a lateral displacement error of the Z-axis table 9Z and compensated for by controlling the X-axis motor 23X. In other words, instead of reducing the rotation error itself, the linearity error caused by the rotation error is compensated for. Therefore, for example, the straightness associated with the movement of the Z-axis table 9Z can be improved with a relatively simple configuration.

[0170] From another point of view, the processing machine 1 has a support part (an extension part of the X-axis bed 19X to the -Z side), a fixed part (Z-axis bed 19Z), a first movable part (Z-axis table 9Z), a scale arrangement part (Z-axis scale arrangement part 21Z), and a two-dimensional scale (Z-axis sensor 25Z). The extension part of the X-axis bed 19X has a first surface (upper surface) facing a third direction (Y direction) perpendicular to the first direction (Z direction) and the second direction (X direction). The Z-axis bed 19Z is supported on the upper surface of the extension part of the X-axis bed 19X. The Z-axis table 9Z is supported by the Z-axis bed 19Z via a linear guide (Z-axis guide 17Z), is guided in the Z direction relative to the Z-axis bed 19Z by the Z-axis guide 17Z, and supports a workpiece 103 or a tool 101 (workpiece 103 in the example of FIG. 1). The Z-axis scale arrangement section 21Z is supported on the upper surface of the extension part of the X-axis bed 19X and is separated from the Z-axis bed 19Z. The Z-axis sensor 25Z outputs a signal according to a first displacement in the Z direction of the Z-axis table 9Z and a first error, which is a displacement in the X direction of the Z-axis table 9Z. The Z-axis sensor 25Z also has a scale section 27 and a detection section 29. The scale section 27 is fixed to the Z-axis scale arrangement section 21Z. The detection section 29 is fixed to the Z-axis table 9Z and outputs a signal according to the relative movement with the scale section 27. The Z-axis scale arrangement section 21Z has a height that exceeds the position of the Z-axis guide 17Z from the upper surface of the extension part of the X-axis bed 19X to the side (+Y side) to which the upper surface faces. The scale section 27 is located on the +Y side of the Z-axis guide 17Z.

[0171] In this case, for example, as described above, the Z-axis sensor 25Z can be brought closer to the virtual plane VP, and the likelihood of the scale unit 27 being deformed with the movement of the Z-axis table 9Z is reduced. When the characteristics of the embodiment are extracted from the above viewpoint, for example, the Z-axis table 9Z does not need to have a fixed positional relationship with the workpiece rotation axis AW in the Y direction.

[0172] The machining system 91 includes the machining machine 1 as described above, and a diagnostic device 93. The diagnostic device 93 acquires information on the detection value of the first error (the error in the X direction of the Z-axis table 9Z) from the machining machine 1, and displays an image according to the acquired information.

[0173] In this case, for example, the state of the guide surface of the Z-axis guide 17Z can be managed by utilizing information for controlling the processing machine 1. In other words, there is no need to add a special measurement system for measuring the state of the guide surface of the Z-axis guide 17Z. Also, the state of the guide surface can be managed in real time during processing. As a result, for example, the likelihood of continuing processing (manufacturing defective products) in a state in which the guide surface has deteriorated with age or is damaged can be reduced at low cost.

[0174] The method for manufacturing a workpiece also includes a processing step in which the workpiece 103 is brought into contact with the tool 101 using the processing machine 1 as described above to process the workpiece 103 into a workpiece.

[0175] In this case, for example, due to the effect of reducing the influence of straightness on machining accuracy, a workpiece with high shape accuracy can be obtained.

[0176] In the above machining step, when a second imaginary plane (imaginary plane VP) is assumed which includes the machining point (see Pp) where the tool 101 contacts the workpiece 103 and is parallel to the first direction (Z direction) and the second direction (X direction), the distance from the second imaginary plane to the two-dimensional scale (Z-axis sensor 25Z) may be less than 1 / 3 of the distance from the second imaginary plane to the linear guide (Z-axis guide 17Z).

[0177] That is, in the description of the embodiment, the virtual plane VP is mainly assumed to include the rotation axis of the spindle (the workpiece rotation axis AW for the Z-axis table 9Z), but in the machining step, a virtual plane VP including the actual machining point may be assumed. This makes it possible to more accurately detect the effect of the error of the Z-axis sensor 25Z on machining.

[0178] <Chapter B Second Embodiment> (7. Overall Configuration of Second Embodiment) In the description of the second embodiment, basically, only the differences from the first embodiment will be described. Matters that are not specifically mentioned may be considered to be the same as the first embodiment or may be inferred from the first embodiment.

[0179] Fig. 8 is a block diagram of a control system of a processing machine 201 according to the second embodiment. This figure corresponds to Fig. 4. However, the illustration of the signal paths from the sensors (225X, 225Y, and 225Z) to the controller 5 is simplified more than that in Fig. 4.

[0180] In short, the second embodiment is an embodiment in which the number of detected errors is greater than that of the first embodiment. More specifically, as can be seen from the output (XPosX, etc.) of each input processing unit (31X, 31Y, or 31Z), a total of six detection values ​​(five of which are errors) are obtained for one movable unit (one axis), which are the translation errors in three directions and the rotation errors around the three axes. The meanings of the six detection values ​​output by the input processing unit have already been described in the explanation of the first embodiment.

[0181] In the processing machine 201, the number of correction units is increased compared to the processing machine 1 due to an increase in the number of types of detection values. Specifically, correction units 32Yx, 32Xy, and 32Zy are added. Correction unit 32Yx converts a rotation error related to the saddle 13 (Y-axis table) into an error in the X direction. Correction unit 32Xy converts a rotation error related to the X-axis table 9X into an error in the Y direction. Correction unit 32Zy converts a rotation error related to the Z-axis table 9Z into an error in the Y direction.

[0182] Furthermore, in the processing machine 201, the number of rotation errors processed by each correction unit also increases with an increase in the number of types of detection values. Specifically, in the first embodiment, one correction unit converts one rotation error into one linear error, but in the second embodiment, one correction unit converts three rotation errors into one linear error. The calculation method may be, for example, to convert three rotation errors separately into three linear errors and add up the three linear errors. The method of converting one rotation error into one linear error has been described in the explanation of the first embodiment.

[0183] In addition, in the processing machine 201, the displacement input to any control unit (33X, 33Y, or 33Z) is the sum (in a broad sense including subtraction) of errors in two directions. For more information, please refer to the explanation of FIG. 5.

[0184] (8. Scale) The configuration of the sensors (225X, 225Y, or 225Z) that detect the three displacements and three rotation errors is arbitrary. An example is shown below.

[0185] FIG. 9 is a perspective view showing the configuration of an X-axis sensor 225X that detects the displacement and rotation error of the X-axis table 9X.

[0186] The X-axis sensor 225X has an X-axis auxiliary scale 26X extending in parallel to the X-axis sensor 25X, in addition to the X-axis sensor 25X (two-dimensional scale) of the first embodiment. The X-axis auxiliary scale 26X has a configuration roughly similar to that of the half of the X-axis sensor 25X having the two detection portions (29a). That is, the X-axis auxiliary scale 26X has a scale portion 27A having a configuration similar to the A-phase scale portion 27a, and two C-phase detection portions 29c having a configuration similar to the two A-phase detection portions 29a (both are collectively referred to as detection portion 29A).

[0187] As will be understood from the description below, the pattern orientation of scale portion 27A can be the same as that of B-phase scale portion 27b. Furthermore, the positions and distances d (FIG. 3) of the two C-phase detection portions 29c in the X direction may be the same as the positions and distances of the two A-phase detection portions 29a (as shown in the example), or may be different. In any case, the description of the A-phase of X-axis sensor 25X may be applied to X-axis auxiliary scale 26X.

[0188] The X-axis sensor 25X and the X-axis auxiliary scale 26X are arranged so that their width directions are perpendicular to each other. For example, the X-axis sensor 25X is arranged in the same direction as in the first embodiment, and the X-axis auxiliary scale 26X is arranged so that the Y direction is the width direction. The two may be adjacent to each other or may be somewhat separated from each other. In FIG. 9, the scale section 27A is located on the B-phase scale section 27b side of the scale section 27, but it may be located on the A-phase scale section 27a side.

[0189] Similar to the A-phase and B-phase, the C-phase detection unit 29c detects a displacement in a direction perpendicular to the pattern 27c of the scale unit 27A. The displacement is dC, the inclination angle with respect to the X-axis in the direction perpendicular to the pattern 27c is θ, the X-direction component of the displacement dC is x1, and the Y-direction component of the displacement dC is y1. In this case, similar to the equation (1) (or the equation (2)), the following equation is established. dC=x1×cosθ+y1×sinθ (7)

[0190] Here, x1 is found from equation (3), and θ is known. Therefore, y1 can be calculated by the following equation. y1=(dC-x1×cosθ) / sinθ (8)

[0191] The rotation error around the Z axis (the error relating to pitch in the illustrated example) can be calculated in the same way as the rotation error around the Y axis (the rotation error relating to yaw in the illustrated example). That is, in the above-mentioned formula (5), z should be replaced with y and A with C.

[0192] The rotation error around the X-axis (error related to roll in the illustrated example) can be calculated, for example, by applying a method for calculating the rotation error around the Y-axis. Specifically, in the YZ plane, a straight line connecting the A-phase detection unit 29a (or the B-phase detection unit 29b) and the C-phase detection unit 29c and a fourth direction perpendicular to the straight line are assumed. The fourth-direction components of z1 and y1 are z1r and y1r, respectively. The distance on the straight line between the A-phase detection unit 29a and the C-phase detection unit 29c is assumed to be d. In this way, the rotation error around the X-axis can be calculated by arctan((z1r-y1r) / d), similar to equation (6).

[0193] There are various other possible sensors (scales) that extend the two-dimensional scale other than those described above. Although not shown in the figures, the following are some examples.

[0194] For example, two two-dimensional scales may be provided on each axis, each extending in the same direction and with width directions perpendicular to each other. The configuration of each of the two-dimensional scales is arbitrary, and they may be the same as each other or different from each other. Note that one half of the two two-dimensional scales may be regarded as an auxiliary scale.

[0195] Also, for example, the auxiliary scale may be half the size of a normal two-dimensional scale (having only a plurality of patterns arranged in the Y direction) rather than half the size of a fishbone-shaped two-dimensional scale. This auxiliary scale may be combined with the fishbone-shaped two-dimensional scale or may be combined with a normal two-dimensional scale. Note that the X-axis auxiliary scale 26X in the illustrated example may also be combined with a normal two-dimensional scale.

[0196] Also, for example, the sensor may be configured the same as or similar to a two-dimensional scale and determine the distance between scale unit 27 and detection unit 29 based on the intensity of a signal generated according to pattern 27c. This may realize a three-dimensional scale that performs three-dimensional detection. In this disclosure, unless otherwise specified or unless there is a contradiction, the two-dimensional scale includes a three-dimensional scale as a type of two-dimensional scale.

[0197] Returning to Fig. 8, the sensor for each axis (225X, 225Y, or 225Z) has the configuration exemplified in Fig. 9. However, for convenience of illustration, the two-dimensional scale (25X, 25Y, or 25Z) and the auxiliary scale (26X, 26Y, or 26Z) are shown on the same plane.

[0198] (9. Summary of the Second Embodiment) The processing machine 201 according to the second embodiment has a similar configuration to the processing machine 1 according to the first embodiment. Therefore, for example, the measurement accuracy of waviness and the like can be improved.

[0199] The processing machine 201 may further have an auxiliary scale (Z-axis auxiliary scale 26Z). The Z-axis auxiliary scale 26Z may extend in the first direction (Z direction) in parallel with the two-dimensional scale (Z-axis sensor 25Z), may have a configuration corresponding to the configuration on one side of the Z-axis sensor 25Z in the width direction, may not have a configuration corresponding to the configuration on the other side of the Z-axis sensor 25Z, and may have a third direction (Y direction) as the width direction.

[0200] In this case, for example, the two-dimensional scale and the auxiliary scale can detect displacement in at least three directions. Also, it is possible to detect (calculate) errors related to roll. In the second embodiment, yaw and pitch can be detected, but only one detection unit (29a or 29c) may be provided in the A phase and / or C phase, and yaw and / or pitch may not be detectable.

[0201] The processing machine 201 may further include an auxiliary scale (Z-axis auxiliary scale 26Z). The Z-axis auxiliary scale 26Z may extend in the first direction (Z direction) in parallel with the two-dimensional scale (Z-axis sensor 25Z) and may output a signal according to a second error which is a displacement of the first movable part (Z-axis table 9Z) in the third direction (Y direction). The processing machine 201 (controller 5 or Z-axis sensor 225Z) may identify a rotation error (error related to roll) around an axis parallel to the first direction (Z direction) based on the first error (error in the X direction of the Z-axis table 9Z) detected by the Z-axis sensor 25Z and the second error detected by the Z-axis auxiliary scale 26Z.

[0202] In this case, for example, errors related to roll can be detected using a two-dimensional scale, and therefore the detection configuration is simplified compared to an embodiment in which other sensors (e.g., a gyro sensor or two laser length measuring devices) are provided to detect roll (such an embodiment may also be included in the technology disclosed herein).

[0203] In the first and second embodiments described above, the Z direction is an example of the first direction, and the Z-axis table 9Z is an example of the first movable part. However, each of the X-axis table 9X and the saddle 13 is also an example of the first movable part, and each of the X direction and the Y direction is also an example of the first direction.

[0204] As described above, when the Z-axis table 9Z is an example of the first movable part, the X direction is an example of the second direction, and the Y direction is an example of the third direction. The X-axis table 9X is an example of the second movable part. The Z-axis motor 23Z is an example of the first drive part, and the X-axis motor 23X is an example of the second drive part. The Z-axis guide 17Z is an example of a linear guide. The Z-axis sensors 25Z and 225Z are each an example of a two-dimensional scale. The work spindle 15W is an example of a spindle, and the work rotation axis AW is an example of a first rotation axis. The extension part of the X-axis bed 19X is an example of a support part, the Z-axis bed 19Z is an example of a fixed part, and the Z-axis scale arrangement part 21Z is an example of a scale arrangement part.

[0205] When the X-axis table 9X, the saddle 13, or the Z-axis table 9Z is an example of the first movable part, the tool spindle 15T can also be an example of the spindle. Also, when the X-axis table 9X is an example of the first movable part, the base 7 is an example of the support part, and the X-axis bed 19X is an example of the fixed part.

[0206] The technology according to the present disclosure is not limited to the above-described embodiments and may be implemented in various forms.

[0207] As described in the description of the embodiment, the processing machine is not limited to the one with the configuration exemplified in FIG. 1. For example, the processing machine is not limited to a special machine tool such as an ultra-precision aspheric processing machine, and may be a general machine tool. In addition, the processing machine is not limited to a machine tool, and may be, for example, a robot. From another perspective, the program including information on commands related to movement is not limited to an NC program, and may be generated by teaching.

[0208] Furthermore, the processing machine is not limited to one that performs grinding and / or polishing, and may be one that performs, for example, cutting or electric discharge machining, or one that can perform two or more of the above-mentioned various processes. The processing may be one in which a non-rotating tool is brought into contact with a rotating workpiece (e.g., turning), one in which a rotating tool is brought into contact with a non-rotating workpiece (e.g., milling), or one in which neither the workpiece nor the tool is rotated.

[0209] The number of movable parts (the number of driven axes) that the processing machine has is arbitrary. For example, the processing machine does not have to have three axes for translation, and conversely, it may have four or more axes.

[0210] Of the multiple axes possessed by the processing machine, the number of axes for which displacement is detected by the two-dimensional scale is arbitrary. Furthermore, in one axis for which displacement is detected by the two-dimensional scale, the number of errors detected out of the five types of errors (linear errors in two directions and rotational errors around three axes) is also arbitrary. For example, the number of axes on which the two-dimensional scale is provided may be one. The number of axes on which the two-dimensional scale is provided and the total number of errors detected may be intermediate between those of the first and second embodiments. In a processing machine with four or more axes, more errors may be detected than in the second embodiment.

[0211] The errors detected by the two-dimensional scale do not have to be used for real-time corrections. For example, errors detected in a test run or in a previous cycle may be used for correction of the NC program, or for cycle-by-cycle corrections by the interpretation unit 39 or the interpolation unit 41. Or, the errors may only be used by the diagnostic device described in the embodiments.

[0212] From the present disclosure, various new technical ideas can be derived that do not necessarily require that the two-dimensional scale be close to a virtual plane, and also various new technical ideas can be derived that do not necessarily require that the two-dimensional scale be placed on a specific scale placement unit. For example, from Fig. 5, a new technical idea can be derived that incorporates the error in the speed of other axes (X-axis and / or Y-axis) into the speed feedback of the target axis (Z-axis). Unlike the embodiment, this technical idea may be applied to a configuration in which the two-dimensional scale is placed directly on the bed and table. [Explanation of symbols]

[0213] 1...machine, 5...controller, 9X...X-axis table (second movable part), 9Z...Z-axis table (first movable part), 15W...work spindle (spindle), 17Z...Z-axis guide (linear guide), 25Z...Z-axis sensor (two-dimensional scale), 101...tool, 103...work, AW...work rotation axis (first rotation axis), VP...virtual plane.

Claims

1. A first movable part that supports a workpiece or a tool; A linear guide that guides the first movable part in a first direction; a two-dimensional scale that outputs a signal corresponding to a first displacement of the first movable part in the first direction and a first error, the first displacement being a displacement of the first movable part in a second direction perpendicular to the first direction; a main shaft having a certain positional relationship with the linear guide in a third direction perpendicular to the first direction and the second direction, and rotating the workpiece or the tool around a first rotation axis parallel to the first direction or the second direction; It has When a virtual plane including the first rotation axis and parallel to the first direction and the second direction is assumed, the distance from the virtual plane to the two-dimensional scale is less than ⅓ of the distance from the virtual plane to the linear guide. processing machine.

2. The two-dimensional scale is located within the virtual plane.

2. The processing machine according to claim 1.

3. A support portion having a first surface facing the imaginary plane; a fixed portion supported by the first surface and supporting the linear guide and the first movable portion; a scale mounting portion supported on the first surface and spaced from the fixed portion; and The two-dimensional scale is a scale portion fixed to the scale arrangement portion; a detection unit that is fixed to the first movable unit and outputs a signal in response to a relative movement between the first movable unit and the scale unit, The scale arrangement portion has a height from the first surface toward the imaginary plane that exceeds the position of the linear guide.

2. The processing machine according to claim 1.

4. The scale mounting portion is a solid metal member. The processing machine according to claim 3.

5. A second movable part that supports the workpiece or the tool; A second drive unit that drives the second movable unit in the second direction; A controller for controlling the second driving unit; and The controller controls the second drive unit so as to reduce an error in the relative velocity of the workpiece and the tool in the second direction caused by the velocity error in the second direction detected by the two-dimensional scale.

2. The processing machine according to claim 1.

6. A first drive unit that drives the first movable unit in the first direction; A controller for controlling the first driving unit; and the two-dimensional scale simultaneously detects two of the first errors at different positions in the first direction; The controller controls the first driving unit so as to reduce an error in the relative position between the workpiece and the tool in the first direction, which is caused by the rotation error, by translating the first movable unit, based on a rotation error about an axis parallel to the third direction identified from the two first errors.

2. The processing machine according to claim 1.

7. A second movable part that supports the workpiece or the tool; A second drive unit that drives the second movable unit in the second direction; A controller for controlling the second driving unit; and the two-dimensional scale simultaneously detects two of the first errors at different positions in the first direction; The controller controls the second driving unit so as to reduce an error in the relative position between the workpiece and the tool in the second direction, which is caused by the rotation error, by translating the second movable unit, based on a rotation error about an axis parallel to the third direction identified from the two first errors.

2. The processing machine according to claim 1.

8. and an auxiliary scale extending in the first direction in parallel with the two-dimensional scale, having a configuration corresponding to a configuration on one side of the two-dimensional scale in the width direction, not having a configuration corresponding to a configuration on the other side of the two-dimensional scale in the width direction, and having the third direction as its width direction.

2. The processing machine according to claim 1.

9. an auxiliary scale extending in the first direction in parallel with the two-dimensional scale and outputting a signal corresponding to a second error which is a displacement of the first movable part in the third direction; A rotation error about an axis parallel to the first direction is determined based on the first error detected by the two-dimensional scale and the second error detected by the auxiliary scale.

2. The processing machine according to claim 1.

10. a support portion having a first surface facing a third direction perpendicular to the first direction and the second direction; A fixing portion supported on the first surface; A first movable part that supports a workpiece or a tool and is supported on the fixed part via a linear guide and is guided in the first direction relative to the fixed part by the linear guide; a scale mounting portion supported on the first surface and spaced from the fixed portion; a two-dimensional scale that outputs a signal corresponding to a first displacement of the first movable part in the first direction and a first error that is a displacement of the first movable part in the second direction; It has The two-dimensional scale is a scale portion fixed to the scale arrangement portion; a detection unit that is fixed to the first movable unit and outputs a signal in response to a relative movement between the first movable unit and the scale unit, The scale arrangement portion has a height that exceeds the position of the linear guide on the side facing the first surface, and the scale portion is located on the side facing the first surface relative to the linear guide. processing machine.

11. A processing machine according to any one of claims 1 to 10, a diagnostic device that acquires information on the detected value of the first error from the processing machine and displays an image corresponding to the acquired information; A processing system having the above structure.

12. A processing step of contacting the workpiece with the tool by using the processing machine according to any one of claims 1 to 10 to process the workpiece into a workpiece. A method for manufacturing a workpiece.

13. In the machining step, when a second imaginary plane is assumed to include a machining point where the tool contacts the workpiece and is parallel to the first direction and the second direction, a distance from the second imaginary plane to the two-dimensional scale is equal to or less than 1 / 3 of a distance from the second imaginary plane to the linear guide. The method for manufacturing a workpiece according to claim 12.

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