JP2009284662A - Positioning device and machine tool device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning device that detects a current coordinate with accuracy in an allowable error range when the power is turned on and starts an operation from the position when the power is turned on without performing a return operation to a prescribed position. <P>SOLUTION: In the positioning device, a moving mechanism has an incremental encoder 23 and an absolute encoder 21 which are for detecting a relative position of a movable part 8 with respect to a fixed part 12. A control device 19 has a storage means that stores corresponding data of signal data of the incremental encoder 23 and those of the absolute encoder 21, an initial-coordinate reading means 25 for calculating an initial coordinate of the movable part 8 from the signal data, read when the power is turned on, of the absolute encoder 21, and a current-coordinate reading means 25 for calculating a current coordinate of the movable part 8 on the basis of the signal data of the incremental encoder 23 which is read after power-on. The current-coordinate reading means has a signal converting means for converting the signal data of the absolute encoder, which is read when the power is turned on, into the signal data of the incremental encoder 23 on the basis of the corresponding data of the storage means in order to calculate the current coordinate of the movable part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positioning device that accurately detects and determines a processing position in an ultra-precision processing machine, and a machine tool device including the positioning device.

  Conventionally, high-performance lenses are used in information communication devices such as optical communication, imaging devices such as digital cameras and camera-equipped mobile phones, AV devices such as DVDs and CDs, and medical devices such as endoscopes. Metal molds for molding these lenses are required to have strict accuracy with a shape accuracy of 100 nm or less and a surface roughness of 10 nm or less. In order to precisely machine non-axisymmetric aspheric surfaces such as these optical lenses, a machine tool capable of machining with a resolution of submicron order by simultaneously controlling a plurality of moving axes and a plurality of rotating axes is manufactured. became. For this reason, an incremental linear encoder having extremely high resolution is used as a linear encoder for detecting a machining position.

  However, the conventional incremental linear encoder cannot directly detect the current position (absolute position) of the movable part when the power is turned on, so it is necessary to perform so-called “origin adjustment” by searching for a predetermined origin by moving the movable part. There is also. Therefore, in order to obtain a stroke end signal when using a linear motor, it was considered to use a low-resolution absolute linear encoder in parallel. According to Patent Document 1 in which such an incremental type linear encoder and an absolute type linear encoder are used in combination, in the position detection device that detects the relative position between the fixed part and the movable part, a position information element (light reflecting pit) is provided on one side. On the other hand, a reading means (light reflection pickup) is provided, and the position information element (signal data) includes an incremental type position information element (signal data) and an absolute type position information element (signal data). The incremental position information is selectively read when the movable part is in operation, and the absolute position information (signal data) is selectively read when the movable part is stopped. The position information suitable for each can be obtained.

  In this way, when an incremental linear encoder and an absolute linear encoder are used together, the absolute linear encoder is the closest to the absolute encoder when the power is turned off after moving the movable part controlled by the pulse signal of the incremental linear encoder and then turned on again. The value of the read value is recognized as the current coordinates, and thereafter the incremental linear encoder is read and operated. For example, the unit reading of the absolute linear encoder is set to 1, and the unit reading of the incremental linear encoder is set to 0.1. The moving part moves in units of 0.1 by the pulse signal of the incremental linear encoder. If the power is turned off when there is a moving part at the position of 9.5 or 10.4, the absolute type is used when the power is turned on again. 10 that is the closest reading value of the linear encoder is read, and the current coordinate is recognized as 10. Actually, when the coordinates when the power is turned off is 10.4, the value is shifted by 0.4 compared to before the power is turned on when the power is turned on, but this is an allowable error range. Not a problem.

However, since the absolute position of the incremental linear encoder cannot be detected, if the total movement distance from the reference coordinate increases, the deviation of the reading value between the incremental linear encoder and the absolute linear encoder increases. For example, if the power is turned off when the coordinate of the movable part is 100.4 in the pulse signal of the incremental linear encoder, the reading value with the absolute linear encoder must be 100 when the power is turned on again. However, due to the difference in accuracy between the absolute linear encoder and the incremental linear encoder, the read value of the nearest absolute linear encoder is a value exceeding the allowable error range of 105 or the like. In this case, even if a command to move to the same position as before turning on the power is issued, it moves to a position shifted by 5 from the original position, and the operation does not become as expected by the operator. Was happening. Therefore, in the past, when the power is turned on, the movable part is always moved to the reference coordinate position (return operation), and the movement is always started from the same position. It corresponded.
Japanese Patent Laid-Open No. 2-74823

  However, moving the movable part to the reference coordinate position (predetermined position) every time the power is turned on is a complicated operation, resulting in a decrease in production efficiency. In the case of a linear motor, in order to operate the motor, it is necessary to perform magnetic pole alignment that matches the phase of the current flowing through the coil when the power is turned on and the relative position of the coil and the magnetic pole. For this magnetic pole alignment, a Hall element for obtaining the position of the magnetic pole by the Hall effect is used. However, the Hall element is expensive, and there is a problem that the entire apparatus becomes larger by the size of the Hall element.

  The present invention has been made in view of the conventional problems, and detects the current coordinates with accuracy within an allowable error range when the power is turned on, and operates from the position when the power is turned on without returning to a predetermined position. It is to provide a positioning device that can be started.

  In order to solve the above-described problem, the structural feature of the invention according to claim 1 is that a moving mechanism in which a movable portion moves with respect to a fixed portion by driving a synchronous motor, and a control for controlling driving of the synchronous motor. In the positioning device, the moving mechanism includes an incremental encoder and an absolute encoder for detecting a relative position of the movable portion with respect to the fixed portion, and the control device is a signal of the absolute encoder. Storage means for storing data and corresponding data of the incremental encoder signal data, initial coordinate reading means for obtaining initial coordinates of the movable part from the absolute encoder signal data read at power-on, and power-on Based on the signal data of the incremental encoder read after that. Current coordinate reading means for obtaining the current coordinates of the movable part, the current coordinate reading means based on the corresponding data of the storage means from the signal data of the absolute encoder read when the power is turned on. Signal converting means for converting to signal data to obtain the current coordinates of the movable part is provided.

  The structural feature of the invention according to claim 2 is that in claim 1, the moving mechanism is a moving mechanism in which the movable portion moves linearly with respect to the fixed portion, and the synchronous motor is a synchronous linear motor, The incremental type encoder is an incremental type linear encoder, the absolute type encoder is an absolute type linear encoder, and the control device is configured to store the storage means from the signal data of the absolute type linear encoder read at power-on. Magnetic pole alignment execution means for performing magnetic pole alignment of the synchronous linear motor based on the data converted into the signal data of the incremental linear encoder based on the corresponding data.

The structural feature of the invention according to claim 3 is that, in claim 1 or 2, the control device is turned on when the movable portion is in a relative position not described in the corresponding data of the storage means . In this case, it is provided with data creation means for creating new correspondence data by linear interpolation based on the correspondence data of the storage means .

  According to a fourth aspect of the present invention, the control device according to any one of the first to third aspects is characterized in that the control device detects the signal data of the absolute linear encoder and the incremental linear encoder during the movement of the movable portion. And data recording means for reading the corresponding signal data and recording the corresponding data of both.

  A structural feature of the invention according to claim 5 is that the machine tool device includes the positioning device according to any one of claims 1 to 4.

  According to the first aspect of the invention, the correspondence of the signal data of the incremental encoder to the signal data of the absolute encoder is stored in advance in the storage means. The initial coordinates at power-on are read by the absolute encoder, but the machine origin and absolute position coordinates captured by the signal data of the absolute encoder are converted from the corresponding data stored in the storage means to the signal conversion means. It can be regarded as data converted into signal data of an incremental encoder, and the coordinates at the time of power-on remain within the allowable error range compared to the coordinates before power-on. The incremental encoder signal data read after power-on is also read based on the absolute position of the converted data within the allowable error range, so the machine was operated from the power-on position. Even in this case, it was possible to make the operation almost as expected by the worker, and every time the power was turned on, it was done to deal with the occurrence of misalignment caused by the difference in accuracy between the incremental encoder and absolute encoder Since the return operation to the predetermined position becomes unnecessary, workability can be improved.

  According to the invention of claim 2, the magnetic pole alignment of the synchronous linear motor is performed based on the signal data of the absolute linear encoder read at power-on or the data converted into the signal data of the incremental linear encoder by the signal converter. Therefore, it is possible to perform the magnetic pole alignment of the movable part at low cost without using an expensive Hall element as in the prior art, and to reduce the size of the apparatus.

  According to the third aspect of the present invention, the current position coordinates of the movable part can be obtained by linear interpolation even when the movable part is at a position not included in the corresponding data of the storage means. As described above, since it is possible to flexibly cope with a position not included in the correspondence data, the positioning workability can be remarkably improved.

  According to the fourth aspect of the present invention, new correspondence data can be created or existing correspondence data can be corrected. Thus, the positioning function can be automatically improved.

  According to the invention which concerns on Claim 5, the machine tool apparatus which operate | moves correctly and accurately can be provided by the positioning device.

  An embodiment in which a positioning device according to the present invention is implemented in an NC machine will be described below with reference to the drawings. FIG. 1 is a schematic plan view showing the structure of the NC processing machine, and FIG. 2 is a schematic view showing a positioning device 3 assembled to a part of the NC processing machine. This NC processing machine 2 corresponds to the machine tool device in the claims.

  The NC machine 2 has a movement axis in which the relative motion between the machining tool and the workpiece is in the left-right direction from the front of the machining machine 2, and the movement in which the relative movement between the machining tool and the workpiece is also in the vertical direction. The axis is the Y axis, and the movement axis along which the relative movement between the machining tool and the workpiece is the front-back direction is the Z axis. And it is a simultaneous 5-axis control processing apparatus which controls 5 axis | shafts which added the B axis | shaft as a rotating shaft around a Y axis, and the C axis as a rotating shaft around a Z axis. The three axes X, Y, and Z are orthogonal to each other.

  As shown in FIG. 1, the NC machine 2 includes a headstock 8 incorporating a spindle motor 6 that rotates the spindle 4 about the C axis, and a Z axis that is movable in the Z axis direction that is the longitudinal direction of the spindle 4. A table 10, a longitudinal support member 12 that movably supports the headstock 8 along a Y-axis direction (vertical direction) orthogonal to the X-axis direction and the Z-axis direction, which will be described later, and a chuck provided at the tip of the spindle 4 14 and an X-axis table 15 that is installed at a position facing the workpiece W held by the chuck 14 and is movable in the X-axis direction (left-right direction in FIG. 1) perpendicular to the Z-axis direction and the Y-axis direction; A turntable 16 mounted on the X-axis table 15 and rotatable about the B-axis parallel to the Y-axis direction (vertical direction), and the tool rest 18 provided on the turntable 16 are orthogonal to the XY・ 3 axes of Z and 2 rotation axes of B ・ C And a control unit 19 for controlling the work.

  The headstock 8 is provided with a pair of sliders 7 in the Y-axis direction (vertical direction) on the back surface, and the sliders 7 are slidably fitted to a pair of guide rails 9 provided on the vertical support member 12. As shown in FIG. 2, an absolute linear encoder 21 and an incremental linear encoder 23 are provided, and the position of the movable part (spindle base 8) relative to the fixed part (vertical support member 12) of the Y-axis linear motor 5 can be detected. It is configured. The slider 7, the guide rail 9, and the Y-axis linear motor 5 constitute a moving mechanism.

  The signals from both the linear encoders 21 and 23 are fed back to the CNC device 25, and the servo amplifier 27 supplies the Y-axis linear motor 5 with power proportional to the error with respect to the command signal from the CNC device 25. ) Position control. Further, by providing a FET (Field Effect Transistor) 35 as a switching element between the servo amplifier 27 and the Y-axis linear motor 5, high voltage energization is possible. Further, as shown in FIG. 5, the storage unit (storage unit) of the CNC device 25 corrects a read value (signal data) based on the signal of the absolute linear encoder 21 to the signal data of the incremental linear encoder 23 ( Correspondence data) 29 is stored. Since the correction table 29 has a huge amount of data if a correspondence table of the incremental linear encoder 23 is created for all the absolute linear encoder 21 signals, for example, the absolute type encoder 23 is moved from the machine origin 0 to the machine end. Corresponding data of the incremental encoder 23 is recorded using a data recording unit, which will be described later, with a signal of the encoder 21 at regular intervals. This operation is performed in advance at the machine assembly stage. At that time, it is better to record the frequently used area by shortening the data interval.

  Further, the CNC device 25 gives the mechanical origin 0 obtained from the signal data of the absolute linear encoder 21 to the signal data of the incremental linear encoder 23, and the signal data (read value) by the absolute linear encoder 21 having a low resolution. Is converted to signal data of the incremental linear encoder 23 having a high resolution based on the correction data of the correction table 29 (corresponding to the initial coordinate reading means, the current coordinate reading means, and the signal conversion means). ing. Further, the CNC device 25 adds the correction data to the correction data when the power is turned on when the movable part (spindle base 8) of the Y-axis linear motor 5 is located at a position not described in the correction data of the correction table 29. It has a data creation unit (data creation means) that can create new correction data by linear interpolation based on it. The new correction data is created by the data creation unit by the following method, for example. First, as shown in FIG. 6, it is assumed that the signal data of the absolute linear encoder 21 and the signal data of the incremental linear encoder 23 have corresponding data at points J and N. The read value of the absolute linear encoder 21 at point J is x (J), the read value of the incremental linear encoder 23 is X (J), and the read value of the absolute linear encoder 21 at point N is x. (N), the reading value of the incremental linear encoder 23 is X (N). Next, at the power-on point DP, since the absolute position is read by the absolute linear encoder 21, it is read that the power is turned on at the closest K point. Then, when the read value based on the signal data of the absolute linear encoder 21 at the K point is x (K), the corresponding data sandwiching the K point is the read value (estimated) X (K) of the incremental linear encoder 23. It is obtained by linear interpolation using two existing points (point J and point N).

  First, (X (K) -X (J)) / (X (N) -X (J)) = (x (K) -x (J)) / (x (N) -x (J)) From the relationship, X (K) = (x (K) -x (J)) (X (N) -X (J)) / (x (N) -x (J)) + X (J) is calculated. , X (K) is obtained. This X (K) is used as new correction data for the read value x (K) of the absolute linear encoder 21 at the K point.

  Further, the CNC device 25 reads the signal data of the absolute linear encoder 21 and the signal data of the incremental linear encoder 23 when the movable unit 8 is moved, and records the corresponding data of the data recording unit ( Data recording means). New correction data created by the data creation unit is also recorded in the data recording unit. The CNC device 25 and the servo amplifier 27 constitute a control device 19. Further, the absolute linear encoder 21, the incremental linear encoder 23, the CNC device 25, and the servo amplifier 27 constitute the positioning device 3.

  The headstock 8 is configured to be movable in the Y-axis direction (vertical direction) with respect to the vertical support member 12 by the Y-axis linear motor 5. As shown in FIGS. 2 and 3, the Y-axis linear motor 5 includes a plurality of magnets 31 arranged so that N poles and S poles are alternately arranged on the fixed part (vertical support member) 12 side, and a movable part (spindle base). ) It is provided on the 8 side, and is composed of the magnet 31 and a plurality of coils 33 which are opposed to each other through magnetic gaps at a plurality of positions. The direction and magnitude of the current flowing through each coil 33 is controlled by the CNC device 25 and added via the servo amplifier 27. In this embodiment, as shown in FIG. 3, a three-phase alternating current having a phase difference of 120 degrees each in the u-phase, v-phase, and w-phase flows in, and the Y-axis linear motor 5 that is a synchronous linear motor is The movable part (spindle base 8) moves in synchronization with the moving magnetic field formed by the coils 33 arranged side by side. Further, for example, a u-phase current flows into the coil 33a, a v-phase current flows into the 33b, and a w-phase current flows into the 33c. Here, the CNC device 25 uses the signal data detected from the absolute linear encoder 21 when the power is turned on, and the coil 33 of the movable portion (spindle base 8) for the plurality of magnets 31 arranged on the fixed portion (vertical support member 12). The magnetic pole aligning means for determining the current phase to flow into the coil 33 of each phase is constructed.

  The vertical support member 12 is fixed on a Z-axis table 10, and the Z-axis table 10 is moved along a Z-axis guide 13 disposed in the Z-axis direction on the base 1 by a linear motor (not shown). It is like that.

  The X-axis table 15 is moved along an X-axis guide 11 installed in the X-axis direction on the base 1 by a linear motor (not shown). A turntable linear motor 17 is arranged in a ring shape around the turntable 16 placed on the X-axis table 15. The turntable linear motor 17 includes a plurality of unillustrated magnets provided so as to surround the turntable 16 on the X-axis table 15, and the turntable 16 so as to face the coil via magnetic gaps at a plurality of locations. It consists of a plurality of unillustrated coils provided on the outer periphery.

  The chuck 14 of the headstock 8 holds the workpiece W and is rotated around the C axis parallel to the Z axis by the spindle motor 6. Further, the movement position of the headstock 8 in the Y-axis direction and the movement positions of the X-axis table 15 and the Z-axis table 10 are detected by a linear encoder (not shown), and the spindle 4 and the turntable 16 are detected by a rotary encoder (not shown). The rotational position is detected. The operation of the linear motor, the spindle motor 6 and the turntable linear motor 17 is controlled by the controller 19 based on the signal data of the moving position and the rotating position.

  The tool post 18 includes a slider (not shown) disposed to be slidable in the Z-axis direction with respect to a slider base (not shown) surrounded by a base frame (not shown) fixed on the turntable 16. A tool holder 20 assembled on the leading end side of the slider, an optical linear scale (not shown) disposed on the proximal end side of the slider, and a linear motor 22 disposed between the slider and the slider base. Consists of A tool 24 as a tool is held in the tool holder 20 in parallel with the Z-axis direction.

  The operation of the NC machine 2 and the positioning device 3 configured as described above will be described below. First, the workpiece W is held on the chuck 14, and the cutting tool 24 is held parallel to the Z axis on the tool holder 20 of the tool rest 18. Then, the height position (Y-axis direction) of the headstock 8 is adjusted to the height position of the cutting tool 24 and the Z-axis table 10 is moved in the Z-axis direction to bring the workpiece W closer to the tool rest 18. In this case, the linear motor is driven. Since each linear motor is driven in the same manner, the Y-axis linear motor 5 will be described as a representative. First, the Y-axis linear motor 5 is turned on. As shown in the graph of FIG. 4, the coordinate position X of the movable part (spindle base 8) at this time with respect to the machine origin 0 and the current value U (X) at the coordinate position are expressed by, for example, Formula (1) Rsin {2π (X + α) / T} (see FIG. 4). The power source will be described on behalf of the u phase of the three-phase alternating current. Point A is a reference point of the absolute linear encoder 21 in which the sine wave of the current indicates 0, and point B is the reference point A. This is a point indicating a position after one cycle. α indicates the distance of the reference point A with respect to the mechanical origin 0, and β indicates the distance of the P point with respect to the B point. Point P is a point indicating the position of the movable part (spindle base 8) when the power is turned on. R indicates the amplitude (current value) of the sine wave of the current, T indicates the length of one cycle of the sine wave of the current, and the width of a pair of adjacent magnets (for example, 30 mm) (see FIG. 3). Corresponding value.

  First, in Equation (1), the value of α is obtained in advance as an initial intercept. Then, the position coordinate (initial coordinate) m of the point P from the mechanical origin 0 is obtained from the signal data of the absolute encoder 21 when the power is turned on. Since the phase at this time is expressed by sin {2π (m + α) / T}, the CNC device 25 calculates the current value of Rsin {2π (m + α) / T} that matches the phase of the u phase at the P point. The magnetic pole alignment (phase alignment) is performed by measuring the timing of energization and flowing it as a command current.

  When the current is applied, the movable portion (spindle base 8) of the Y-axis linear motor 5 moves. However, as shown in FIG. 5, the signal data of the absolute linear encoder 21 when the power is turned on (for example, 0 as the read value). .000200 mm) is converted into the signal data (0.0002105 mm) of the incremental linear encoder 23 based on the correction table 29 stored in the storage unit of the CNC device 25, and the movable part ( Used for position control of the headstock 8). Then, the current coordinates are obtained from the signal data detected by the incremental linear encoder 23 after the power is turned on, the position of the current coordinates is fed back to the CNC device 25, and power proportional to the error with respect to the command signal from the CNC device 25 is obtained. The servo amplifier 27 supplies the coil 33 of the Y-axis linear motor 5. Thus, since the position control of the current coordinates of the movable portion (spindle head 8) can be performed using the signal data of the high-resolution incremental linear encoder 23, high-precision machining can be performed.

  A linear motor (not shown) that moves the X-axis table 15 in the X-axis direction, a linear motor (not shown) that moves the Z-axis table 10 in the Z-axis direction, and a turn that rotates the turntable 16 around the B-axis. Similarly, for the table linear motor 17, the initial coordinates are obtained by an absolute linear encoder (not shown) when the power is turned on, and the current coordinates are obtained by an incremental linear encoder (not shown) after the power is turned on. To do.

  In the actual machining of the workpiece W, the spindle motor 6 is rotated to rotate the workpiece W around the C axis, while the X axis, the Y axis and the Z axis are orthogonal to each other, the B axis and By performing simultaneous 5-axis control around the C-axis with the control device 19, extremely precise machining is realized.

  According to the positioning device 3 in the above embodiment, magnetic pole alignment of a synchronous linear motor (such as the Y-axis linear motor 5) can be performed based on the signal data of the absolute linear encoder 21, so that it is expensive as in the past. Without using a Hall element, the movable part (headstock 8) can be positioned at low cost, and the entire apparatus can be downsized. Further, the correspondence of the signal data of the incremental linear encoder 23 to the signal data of the absolute linear encoder 21 is stored in advance in the storage unit (CNC device 25), and the initial coordinates when the power is turned on are determined by the absolute linear encoder 21. Although read, the machine origin and absolute position coordinates captured by the signal data of the absolute linear encoder 21 are converted into the signal data of the incremental linear encoder 23 by the signal converter (CNC device 25) based on the stored data. The coordinates when the power is turned on remain within the allowable error range compared to the coordinates before the power is turned on. The signal data of the incremental linear encoder 23 that is read after the power is turned on is also read based on the absolute position of the converted data within the allowable error range. Can be operated almost as expected by the operator, and every time the power is turned on, misalignment occurs due to the difference in accuracy between the incremental linear encoder and absolute linear encoder. This eliminates the need for the return operation to the predetermined position, which has been performed in order to cope with the above, and thus the workability can be greatly improved. Even when the movable part (spindle base 8) is at a position not included in the corresponding data of the storage part (CNC device 25), the movable part (spindle base 8) is obtained by linear interpolation in the data creation part (CNC device 25). ) Current position coordinates can be obtained. As described above, since it is possible to flexibly cope with a position not included in the correspondence data, the positioning workability can be remarkably improved. In addition, new correspondence data can be created by the data recording unit (CNC device 25), or existing correspondence data can be corrected. Thus, the positioning function can be automatically improved. By providing such a positioning device 3, it is possible to provide an NC processing machine 2 that operates accurately and precisely.

  In the above embodiment, the machine tool device is an NC machine capable of simultaneous 5-axis control. However, the present invention is not limited to this, and any machine tool driven by a linear motor by a control device may be used.

  Further, the moving mechanism is not limited to linear movement, and the movable part may rotate relative to the fixed part. The incremental encoder and the absolute encoder are not limited to linear encoders, for example, incremental rotary. An encoder and an absolute rotary encoder may be used.

The plane schematic diagram of the NC processing machine used for the embodiment concerning the present invention. The schematic diagram which shows the positioning device provided in a part of NC processing machine. The schematic diagram which shows a synchronous linear motor. The graph which shows the sine wave energized to u phase. The figure which shows the example of a response | compatibility of the signal data of an absolute linear encoder, and the signal data of an incremental linear encoder. The figure which shows the method of calculating | requiring corresponding data by linear interpolation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Machine tool apparatus (NC processing machine), 3 ... Positioning device, 5 ... Movement mechanism (Y-axis linear motor), 7 ... Movement mechanism (slider), 8 ... Movable part (headstock), 9 ... Movement mechanism (guide) Rail), 12 ... fixed part (vertical support member), 19 ... control device, 21 ... absolute linear encoder, 23 ... incremental linear encoder, 25 ... control device, initial coordinate reading means, magnetic pole aligning means, current coordinate reading means Storage means, signal conversion means, data creation means, data recording means (CNC device), 27 ... control device (servo amplifier), 29 ... signal conversion means (correction table).

Claims (5)

In a positioning device having a moving mechanism in which a movable portion moves relative to a fixed portion by driving a synchronous motor, and a control device that controls driving of the synchronous motor,
The moving mechanism includes an incremental encoder and an absolute encoder for detecting a relative position of the movable part with respect to the fixed part,
The controller is
Storage means for storing correspondence data of the signal data of the absolute encoder and the signal data of the incremental encoder;
Initial coordinate reading means for obtaining initial coordinates of the movable part from the signal data of the absolute encoder read at power-on;
Current coordinate reading means for obtaining the current coordinates of the movable part based on the signal data of the incremental encoder read after power-on,
The current coordinate reading means converts the absolute encoder signal data read when the power is turned on into signal data of the incremental encoder based on corresponding data of the storage means to obtain a current coordinate of the movable part A positioning device comprising means. In Claim 1, the said moving mechanism is a moving mechanism in which a movable part moves linearly with respect to a fixed part,
The synchronous motor is a synchronous linear motor,
The incremental encoder is an incremental linear encoder,
The absolute encoder is an absolute linear encoder,
The controller is configured to convert the signal of the synchronous linear motor from the signal data of the absolute linear encoder read at power-on to the signal data of the incremental linear encoder based on the corresponding data of the storage unit. A positioning apparatus comprising magnetic pole alignment means for performing magnetic pole alignment.   3. The linear interpolation according to claim 1, wherein when the power is turned on when the movable unit is in a relative position not described in the correspondence data of the storage unit, the control device performs linear interpolation based on the correspondence data of the storage unit. A positioning apparatus comprising data creating means for creating new correspondence data according to the above.   4. The control device according to claim 1, wherein the control device reads the signal data of the absolute linear encoder and the signal data of the incremental linear encoder during the movement of the movable portion, and records correspondence data between the two. A positioning apparatus characterized by comprising data recording means for carrying out the processing.   A machine tool device comprising the positioning device according to any one of claims 1 to 4.

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