Position correction device, position correction program, and position correction method

Abstract

This position correction device comprises: a thermal displacement amount estimation unit (13) that estimates the thermal displacement amount of a machine tool (3) having a movable part on the basis of a thermal image in which the machine tool (3) is imaged by an infrared imaging device (4) having an infrared imaging element and a shutter provided on the optical path of infrared light impinging on the infrared imaging element; a correction amount generation unit (14) that generates a correction amount for the position of the movable part on the basis of the estimated thermal displacement amount; and a control unit (15) that determines the timing for executing calibration involving imaging in a state in which the shutter is closed, and instructs the infrared imaging device (4) to execute calibration at the determined timing.

Description

Position correction device, position correction program, and position correction method 【0006】 , 【0001】 The present disclosure relates to a position correction device, a position correction program, and a position correction method for correcting the position of a movable part of a machine tool. 【0002】 In a machine tool that moves a movable part by a drive mechanism, the structure of the machine tool may be deformed by the generation of heat, and the positioning accuracy of the movable part may be reduced. For example, in a machine tool that moves a tool attached to a spindle, when the structure of the machine tool is deformed by heat, the position of the tool with respect to the workpiece or the posture of the tool with respect to the workpiece changes, resulting in machining errors. The change in the position of the tool with respect to the workpiece or the posture of the tool with respect to the workpiece is referred to as the thermal displacement of the machine tool. 【0003】 Patent Document 1 discloses an error analysis device for analyzing errors in industrial equipment. A model is generated by machine learning of a dataset in which a thermal image and an error during the operation of the industrial equipment are paired, and the amount of thermal displacement of the industrial equipment is estimated based on the model and the acquired thermal image. The error analysis device according to Patent Document 1 determines a mechanical structure that has a large influence on thermal displacement and acquires the temperature of the mechanical structure that has a large contribution to thermal displacement, thereby estimating the amount of thermal displacement. 【0004】 International Publication No. 2023 / 188493 【0005】 An infrared imaging device that captures a thermal image generally performs calibration periodically by imaging in a state where the shutter is closed as a measure to reduce variations in the outputs of a plurality of infrared detection elements included in the infrared imaging device. The more frequently the calibration is performed, the shorter the period until the number of operations of the shutter reaches the durability number, which is a measure of the life of the infrared imaging device. On the other hand, if the frequency of calibration is simply lowered, it becomes difficult to obtain the temperature information necessary for highly accurate position correction of the machine tool, resulting in a decrease in the accuracy of position correction by the position correction device. 【0006】This disclosure has been made in view of the above, and aims to provide a position correction device that can extend the lifespan of an infrared imaging device for capturing thermal images and enable high-precision position correction for thermal displacement of a machine tool. 【0007】 To solve the above-mentioned problems and achieve the objective, the position correction device according to this disclosure comprises: a thermal displacement estimation unit that estimates the amount of thermal displacement of a machine tool having a movable part based on a thermal image taken by an infrared imaging device having an infrared image sensor and a shutter provided on the optical path of infrared rays incident on the infrared image sensor; a correction amount generation unit that generates a correction amount for the position of the movable part based on the estimated amount of thermal displacement; and a control unit that determines the timing for performing calibration involving shooting with the shutter closed and instructs the infrared imaging device to perform calibration at that timing. 【0008】 The position correction device described herein has the effect of extending the lifespan of an infrared imaging device that captures thermal images, and enabling highly accurate position correction for thermal displacement of machine tools. 【0009】Figures showing an example configuration of the processing system according to Embodiment 1. Figures showing an example configuration of the machine tool in the processing system according to Embodiment 1. Figures showing an example configuration of the infrared imaging device in the processing system according to Embodiment 1. Figure 1 for explaining the thermal image captured by the infrared imaging device in the processing system according to Embodiment 1. Figure 2 for explaining the thermal image captured by the infrared imaging device in the processing system according to Embodiment 1. Figure 3 for explaining the thermal image captured by the infrared imaging device in the processing system according to Embodiment 1. Flowchart showing an example of the operation procedure of the control device in the processing system according to Embodiment 1. Figures showing an example configuration of the processing system according to Embodiment 2. Figures showing an example configuration of the infrared imaging device in the processing system according to Embodiment 2. Figures showing an example configuration of the processing system according to Embodiment 4. Figures showing an example of the internal temperature estimation by the internal temperature estimation unit in the control device according to Embodiment 4. Figures showing an example configuration of the processing system according to Embodiment 5. Figures showing an example of the internal temperature estimation by the internal temperature estimation unit in the control device according to Embodiment 5. Figures showing examples of hardware configurations that realize the control devices according to Embodiments 1 to 5. 【0010】 The position correction device, position correction program, and position correction method according to the embodiment will be described in detail below with reference to the drawings. 【0011】 Embodiment 1. Figure 1 shows an example of the configuration of a processing system 1A according to Embodiment 1. The processing system 1A is a system that performs processing using a machine tool 3. The processing system 1A comprises a control device 2A, a machine tool 3, and an infrared imaging device 4. The control device 2A controls the machine tool 3. The control device 2A also functions as a position correction device that corrects the position of the movable parts of the machine tool 3. The infrared imaging device 4 captures a thermal image of the machine tool 3. 【0012】Figure 2 shows an example of the configuration of the machine tool 3 in the machining system 1A according to Embodiment 1. In Embodiment 1, the machine tool 3 is a vertical orthogonal three-axis cutting machine. The X, Y, and Z axes are three mutually orthogonal axes. The machine tool 3 processes the workpiece by driving multiple axes, which are feed axes, to move the tool and workpiece relative to each other. In Figure 2, the direction of the arrow representing the X axis is the positive X direction, and the opposite direction of the positive X direction is the negative X direction. The direction of the arrow representing the Y axis is the positive Y direction, and the opposite direction of the positive Y direction is the negative Y direction. The direction of the arrow representing the Z axis is the positive Z direction, and the opposite direction of the positive Z direction is the negative Z direction. 【0013】 The machine tool 3 comprises a bed 30 which is the base of the machine tool 3, a column 31 fixed to the bed 30, a table 32 on which the workpiece 35 is fixed, a head 33 supported by the column 31, and a spindle 34 attached to the head 33. The tool 36 is attached to the spindle 34. The tool 36 is used to machine the workpiece 35. 【0014】 The machine tool 3 comprises a spindle drive system, an X-axis drive system 37X, a Y-axis drive system 37Y, and a Z-axis drive system 37Z. The spindle drive system rotates the tool 36 attached to the spindle 34. The tool 36 rotates due to the driving force of the motor in the spindle drive system. Note that the spindle drive system is not shown in the illustration. The X-axis drive system 37X, the Y-axis drive system 37Y, and the Z-axis drive system 37Z are each linear feed drive systems. 【0015】The X-axis drive system 37X includes a ball screw, a motor that rotates the ball screw, and a mechanism that converts the rotational motion of the ball screw into linear motion in the X-axis direction. The X-axis drive system 37X drives the head 33 in the X-axis direction. The Y-axis drive system 37Y includes a ball screw, a motor that rotates the ball screw, and a mechanism that converts the rotational motion of the ball screw into linear motion in the Y-axis direction. The Y-axis drive system 37Y drives the table 32 in the Y-axis direction. The Z-axis drive system 37Z includes a ball screw, a motor that rotates the ball screw, and a mechanism that converts the rotational motion of the ball screw into linear motion in the Z-axis direction. The Z-axis drive system 37Z drives the head 33 in the Z-axis direction. The machine tool 3 moves the tool 36 using the X-axis drive system 37X and the Z-axis drive system 37Z, and moves the workpiece 35 using the Y-axis drive system 37Y, thereby moving the workpiece 35 and the tool 36 relative to each other. 【0016】 The X-axis drive system 37X and the Z-axis drive system 37Z constitute a drive mechanism that drives the spindle 34 to which the tool 36 is attached. The Y-axis drive system 37Y constitutes a drive mechanism that drives the table 32 to which the workpiece 35 is fixed. The spindle 34 and the table 32 are both movable parts that can be moved by the drive mechanism. 【0017】 Each of the spindle drive system, X-axis drive system 37X, Y-axis drive system 37Y, and Z-axis drive system 37Z is connected to the control device 2A. The control device 2A generates commands to control each drive system according to the machining program, which is an NC (Numerical Control) program, and sends commands to each drive system. The spindle drive system rotates the tool 36 according to the commands. The X-axis drive system 37X and the Z-axis drive system 37Z each drive the spindle 34 according to the commands. The Y-axis drive system 37Y drives the table 32 according to the commands. 【0018】In Embodiment 1, deformation of the machine tool 3's structure due to heat is referred to as thermal deformation. Structural deformation of the machine tool 3 refers to deformation of the structural members of the machine tool 3, or deformation of the components of each drive system of the machine tool 3. The structural members of the machine tool 3 are the bed 30, column 31, table 32, or head 33. When the position of the tool 36 relative to the workpiece 35 changes due to thermal deformation of the machine tool 3, the amount of movement of the tool 36 relative to the workpiece 35 is referred to as the thermal displacement of the machine tool 3. 【0019】 In the above description, machine tool 3 is assumed to have a three-axis linear feed drive system. However, machine tool 3 is not limited to having a three-axis linear feed drive system. Machine tool 3 may also be a lathe or other machine with a two-axis linear feed drive system. 【0020】 As shown in Figure 1, the control device 2A includes an acquisition unit 10, a recording unit 11, a preprocessing unit 12, a thermal displacement estimation unit 13, a correction amount generation unit 14, a control unit 15, a display unit 16, a learning unit 17, and a model holding unit 18. 【0021】 The infrared imaging device 4 captures a thermal image of the machine tool 3 and transmits the thermal image to the control device 2A. The acquisition unit 10 receives the thermal image from the infrared imaging device 4 and acquires the thermal image. The acquisition unit 10 outputs the acquired thermal image data to the recording unit 11. The recording unit 11 records the thermal image acquired by the acquisition unit 10. 【0022】 The control device 2A may also convert the thermal image data acquired by the acquisition unit 10 into compressed data by compression encoding of the thermal image. In this case, the recording unit 11 records the compressed data obtained by compression encoding of the thermal image. 【0023】 The preprocessing unit 12 reads thermal image data from the recording unit 11 and processes the read data. The preprocessing unit 12 extracts temperature data from the thermal image. The preprocessing unit 12 outputs the extracted temperature data to the thermal displacement estimation unit 13. 【0024】The thermal displacement estimation unit 13 estimates the thermal displacement of the machine tool 3 based on the temperature data extracted by the preprocessing unit 12. The thermal displacement estimation unit 13 outputs information indicating the estimated thermal displacement to the correction amount generation unit 14. 【0025】 The correction amount generation unit 14 generates a correction amount for the position of the movable part, i.e., the main shaft 34 or the table 32, based on the thermal displacement amount estimated by the thermal displacement amount estimation unit 13. The correction amount generation unit 14 outputs information indicating the generated correction amount to the control unit 15. 【0026】 The control unit 15 generates commands according to the machining program and sends commands to each drive system of the machine tool 3. The control unit 15 controls the machine tool 3 by sending commands to each drive system. In addition, if information indicating a correction amount is input to the control unit 15, the control unit 15 generates a command that reflects the correction amount. As a result, the control unit 15 controls the machine tool 3 based on the command that reflects the correction amount calculated by the correction amount generation unit 14. The machine tool 3 sends information indicating the position of the spindle 34 in the X-axis and Z-axis directions and information indicating the position of the table 32 in the Y-axis direction to the control device 2A. That is, the control device 2A receives position information indicating the position of the movable parts from the machine tool 3. The control unit 15 adjusts the control of the machine tool 3 based on the error between the position indicated in the position information and the commanded position. 【0027】 The control unit 15 controls the infrared imaging device 4 by transmitting control signals to the infrared imaging device 4. Details of the control of the infrared imaging device 4 by the control unit 15 will be described later. 【0028】 The display unit 16 reads the thermal image from the recording unit 11 and displays the thermal image. The control device 2A outputs the thermal image read from the recording unit 11 by displaying it on the display unit 16. 【0029】The learning unit 17 learns the relationship between the temperature of the machine tool 3 and the amount of thermal displacement of the machine tool 3. The learning unit 17 generates a model based on the learned relationship between the temperature of the machine tool 3 and the amount of thermal displacement of the machine tool 3. The learning unit 17 outputs the generated model to the model holding unit 18. The model holding unit 18 holds the model generated by the learning unit 17. 【0030】 The thermal displacement estimation unit 13 reads the model from the model holding unit 18 and estimates the thermal displacement of the machine tool 3 by inputting temperature data extracted from the thermal image into the model. In other words, the thermal displacement estimation unit 13 estimates the thermal displacement of the machine tool 3 by inputting temperature data into a model that has learned the relationship between the temperature of the machine tool 3 and the thermal displacement of the machine tool 3. 【0031】 Figure 3 shows an example of the configuration of an infrared imaging device 4 included in the processing system 1A according to Embodiment 1. The infrared imaging device 4 comprises a housing 41 having an opening through which infrared rays pass, a lens barrel 42 attached to the opening of the housing 41, and a lens 44 attached inside the lens barrel 42. An infrared image sensor 45, a readout circuit board 46, a drive processing circuit board 47, and a temperature sensor 49 are housed inside the housing 41. The infrared imaging device 4 can be installed in any location by a connector 43 attached to the outside of the housing 41. 【0032】 The infrared image sensor 45 is equipped with a plurality of infrared detection elements corresponding to pixels. The readout circuit board 46 is a board having a readout circuit. The readout circuit is a circuit that reads signals from each infrared detection element of the infrared image sensor 45. The infrared image sensor 45 is mounted on the readout circuit board 46. The drive processing circuit board 47 is a board having a drive processing circuit. The drive processing circuit has a drive circuit section responsible for driving the infrared image sensor 45 and a signal processing circuit section responsible for processing the signals read out from each infrared detection element. 【0033】The shutter 48 is located on the path of infrared light incident on the infrared image sensor 45. In the example shown in Figure 3, the shutter 48 is positioned between the lens 44 and the infrared image sensor 45. That is, the shutter 48 is positioned behind the lens 44. The shutter 48 may also be positioned in front of the lens 44 instead of behind it. 【0034】 The temperature sensor 49 detects the temperature of the infrared imaging device 4. In the example shown in Figure 3, the temperature sensor 49 is mounted on the back of the read circuit board 46. The back of the read circuit board 46 is the side of the read circuit board 46 opposite to the side on which the infrared image sensor 45 is mounted. The temperature sensor 49 may be mounted in a location other than the back of the read circuit board 46 of the infrared imaging device 4. The temperature sensor 49 may be mounted, for example, on the housing 41. Alternatively, the temperature sensor 49 may be implemented by wiring embedded in the infrared image sensor 45. 【0035】 In the above, the infrared imaging device 4 is provided with two circuit boards: a readout circuit board 46 and a drive processing circuit board 47. The infrared imaging device 4 may have three or more circuit boards, or it may have just one. The configuration of the infrared imaging device 4 is not limited to the configuration shown in Figure 3. 【0036】The infrared imaging device 4 performs calibration by taking a photograph with the shutter 48 closed. Hereinafter, calibration by taking a photograph with the shutter 48 closed will be referred to as shutter calibration. The control unit 15 determines the timing for the infrared imaging device 4 to perform shutter calibration and instructs the infrared imaging device 4 to perform shutter calibration at that timing. The control unit 15 instructs the infrared imaging device 4 to perform shutter calibration by sending a control signal. The infrared imaging device 4 performs shutter calibration according to the control signal sent from the control unit 15. By closing the shutter 48 and driving the infrared image sensor 45, the closed shutter 48 is photographed. The infrared imaging device 4 performs adjustments based on the information obtained from the photograph. In this way, the infrared imaging device 4 performs shutter calibration according to the instructions of the control unit 15. 【0037】 The control unit 15 sends a control signal to the infrared imaging device 4 to take a thermal image after shutter calibration has been performed. The infrared imaging device 4 takes a thermal image by driving the infrared image sensor 45 with the shutter 48 open, in accordance with the control signal. In this way, the infrared imaging device 4 takes a thermal image of the machine tool 3. By taking a thermal image immediately after shutter calibration has been performed, the infrared imaging device 4 can obtain a high-precision thermal image. 【0038】 Next, the thermal images captured by the infrared imaging device 4 will be described. Figure 4 is the first diagram illustrating the thermal images captured by the infrared imaging device 4 of the processing system 1A according to Embodiment 1. Figure 5 is the second diagram illustrating the thermal images captured by the infrared imaging device 4 of the processing system 1A according to Embodiment 1. Figure 6 is the third diagram illustrating the thermal images captured by the infrared imaging device 4 of the processing system 1A according to Embodiment 1. 【0039】The thermal image captured by the infrared imaging device 4 consists of multiple pixels arranged in a two-dimensional direction. In the example shown in Figures 4 to 6, it is assumed that six pixels are arranged vertically and six horizontally in the thermal image. A pixel is the smallest unit that constitutes a thermal image. The thermal image visually represents the temperature value shown in each pixel. In the example shown in Figures 4 to 6, the infrared imaging device 4 is assumed to be capturing the side of the machine tool 3. Figure 4 shows a simplified side of the machine tool 3, and the imaging range of the infrared imaging device 4 is superimposed on the side of the machine tool 3. The dashed lines in Figure 4 represent the boundaries of pixels. 【0040】 The value of each pixel in the thermal image represents the temperature detected by the infrared imaging device 4. In Figure 5, the temperature differences shown in each pixel are represented by the density of the halftone dots. In Figure 5, the darker the halftone dot, the higher the temperature. In Figure 6, the temperature shown in each pixel is represented numerically. In Figure 6, the unit of temperature is degrees Celsius. 【0041】 The display unit 16 displays a thermal image as shown in Figure 5. The display unit 16 may also display a numerical representation of the temperature along with the thermal image, or in place of the thermal image, as shown in Figure 6. The display unit 16 may also superimpose the thermal image as shown in Figure 5 onto a simplified diagram showing the configuration of the machine tool 3, as shown in Figure 4. 【0042】In Figure 4, the entire side of the machine tool 3 is photographed using one infrared imaging device 4, but this is not the only option. The orientation in which the machine tool 3 is photographed by the infrared imaging device 4 is arbitrary. The processing system 1A may also photograph the machine tool 3 using multiple infrared imaging devices 4. In this case, the acquisition unit 10 acquires the thermal image output from each of the multiple infrared imaging devices 4. Furthermore, the infrared imaging devices 4 may not photograph the entire machine tool 3, but only a part of it. In this case, the acquisition unit 10 acquires a thermal image of only a part of the machine tool 3, not a thermal image of the entire machine tool 3. The processing system 1A may also acquire the temperature distribution of the entire machine tool 3 or a part of the machine tool 3 by stitching together multiple thermal images taken by the multiple infrared imaging devices 4. Furthermore, the number of pixels constituting the thermal image is not limited to the above case, but is arbitrary. 【0043】 Next, the timing of when the infrared imaging device 4 performs shutter calibration will be described. In Embodiment 1, the control unit 15 instructs the infrared imaging device 4 to perform shutter calibration when the machine tool 3 reaches a predetermined state before starting machining. The control unit 15 determines whether the machine tool 3 has reached a predetermined state based on the control signal sent from the control unit 15 to the machine tool 3. Alternatively, the control unit 15 obtains information indicating the state of the machine tool 3 from the machine tool 3 and determines whether the machine tool 3 has reached a predetermined state based on the obtained information. 【0044】Here, an example in which the infrared imaging device 4 performs shutter calibration when the machine tool 3 is in a specified state before starting processing will be described. In one example, before the machine tool 3 starts processing, when the coordinate system of the workpiece or the tool to be processed by the machine tool 3 is set, the control unit 15 instructs the infrared imaging device 4 to execute shutter calibration. The time when the coordinate system of the workpiece or the coordinate system of the movable part is set means when the coordinate system of the workpiece or the tool is newly created or updated. The infrared imaging device 4 executes shutter calibration according to the instruction from the control unit 15 at this timing. Further, immediately after the shutter calibration, the infrared imaging device 4 takes a thermal image according to the instruction from the control unit 15. Thereby, the control device 2A acquires the thermal image at the time origin with the time immediately after the coordinate system of the workpiece or the tool is set as the time origin. The time origin can also be said to be the origin in the time series of the thermal images recorded in the recording unit 11. 【0045】 Alternatively, when the machine tool 3 performs low-load operation for a certain period immediately after starting, that is, when performing warm-up operation, the control unit 15 may instruct the infrared imaging device 4 to execute shutter calibration when the warm-up operation ends. The control device 2A can execute shutter calibration and acquire a thermal image after the state of the machine tool 3 has stabilized due to the warm-up operation. Thereby, the control device 2A can estimate the thermal displacement amount with high accuracy. 【0046】 The machine tool 3 may be provided with a button for instructing shutter calibration or acquisition of a thermal image. When the button is pressed by an operator operating the machine tool 3, the control unit 15 may instruct the infrared imaging device 4 to execute shutter calibration. The control device 2A can execute shutter calibration and acquire a thermal image at the timing desired by the operator. 【0047】The timing at which the infrared imaging device 4 performs shutter calibration may be other than when the machine tool 3 is in a specified state before starting processing. The timing at which the infrared imaging device 4 performs shutter calibration may also be when the machine tool 3 is performing processing. For example, shutter calibration may be performed when the movable part reaches a specified position. In this case, the control unit 15 instructs the infrared imaging device 4 to perform shutter calibration when the movable part moves to the specified position. Here, the specified position may be a position strictly defined by the coordinates of the movable part, or a position near the defined position. The position near the defined position is a position within a predetermined distance from the defined position. The distance is determined based on, for example, the spatial resolution per pixel of the infrared imaging device 4. 【0048】 Here, it is assumed that a thermal image acquired when the movable part is at a specific position is used for the learning when the learning unit 17 generates a model. The control unit 15 designates the position of the movable part when the thermal image used for learning is acquired, and determines that the time when the movable part moves to that position is the timing for performing shutter calibration. The control device 2A acquires a thermal image when the learning thermal image is acquired and when the movable part is at the same position, and estimates the thermal displacement amount. Thereby, the control device 2A can estimate the thermal displacement amount with high accuracy. 【0049】 The thermal displacement amount is correlated with the temperature change of the machine tool 3. Although it depends on the type of the machine tool 3, generally, it is said that a machining error of several μm occurs due to a temperature change of several °C. Therefore, it can be said that in order to obtain a machining accuracy with a machining error of 10 μm or less, it is necessary to estimate the temperature of the machine tool 3 with an accuracy of several °C. 【0050】The control device 2A can estimate the temperature of the machine tool 3 with high accuracy by acquiring a thermal image immediately after performing shutter calibration. Based on the temperature estimation, the control device 2A can estimate the amount of thermal displacement with high accuracy. As a result, the machining system 1A can have the machine tool 3 perform high-precision machining. 【0051】 As described above, the control device 2A determines the timing for shutter calibration when the machine tool 3 reaches a predetermined state before starting machining. Alternatively, the control device 2A determines the timing for shutter calibration when the movable part moves to a predetermined position. This allows the control device 2A to obtain the temperature information necessary for high-precision position correction of the machine tool 3, enabling high-precision position correction. Furthermore, the frequency of shutter calibration is reduced compared to when the infrared imaging device 4 is powered on and shutter calibration is repeated at a predetermined cycle. Reducing the frequency of shutter calibration reduces the number of times the shutter 48 operates, thus extending the lifespan of the infrared imaging device 4. 【0052】 Next, the operation procedure of the control device 2A will be described. Figure 7 is a flowchart showing an example of the operation procedure of the control device 2A in the machining system 1A according to Embodiment 1. Here, the operation procedure when the control device 2A corrects the position of the movable part of the machine tool 3 will be described. 【0053】 In step S1, the control unit 15 of the control device 2A determines whether or not to have the infrared imaging device 4 perform shutter calibration. In other words, the control unit 15 determines whether or not it is time to perform shutter calibration. If it is determined not to perform shutter calibration (step S1, No), the control unit 15 repeats step S1. On the other hand, if it is determined to perform shutter calibration (step S1, Yes), the control device 2A proceeds to step S2. 【0054】In step S2, the control unit 15 instructs the infrared imaging device 4 to perform shutter calibration. The infrared imaging device 4 performs shutter calibration in accordance with the instructions from the control unit 15. Immediately after performing shutter calibration, the infrared imaging device 4 takes a thermal image of the machine tool 3 in accordance with the instructions from the control unit 15. 【0055】 In step S3, the acquisition unit 10 of the control device 2A acquires a thermal image captured by the infrared imaging device 4. The thermal image acquired by the acquisition unit 10 is recorded in the recording unit 11. The preprocessing unit 12 reads the thermal image data from the recording unit 11. The preprocessing unit 12 extracts temperature data from the thermal image. 【0056】 In step S4, the thermal displacement estimation unit 13 estimates the thermal displacement of the machine tool 3 based on the temperature data extracted by the preprocessing unit 12. The thermal displacement estimation unit 13 outputs information indicating the estimated thermal displacement to the correction amount generation unit 14. 【0057】 In step S5, the correction amount generation unit 14 generates a correction amount for the position of the main shaft 34 based on the thermal displacement amount estimated in step S4. The correction amount generation unit 14 outputs information indicating the generated correction amount to the control unit 15. 【0058】 In step S6, the control unit 15 controls the machine tool 3 based on a command that reflects the correction amount generated in step S5. The control unit 15 generates a command that reflects the correction amount and sends the command to each drive system of the machine tool 3, thereby controlling the machine tool 3 based on the command that reflects the correction amount. The position of the spindle 34 is corrected as the machine tool 3 operates the spindle 34 in accordance with the command sent from the control unit 15. With this, the control device 2A completes its operation according to the procedure shown in Figure 7. 【0059】According to Embodiment 1, the control device 2A includes a thermal displacement estimation unit 13 that estimates the amount of thermal displacement of the machine tool 3 based on a thermal image taken of the machine tool 3 having a movable part by an infrared imaging device 4, a correction amount generation unit 14 that generates a correction amount for the position of the movable part based on the estimated amount of thermal displacement, and a control unit 15 that determines the timing for performing shutter calibration and instructs the infrared imaging device 4 to perform shutter calibration at that timing. As a result, the control device 2A has the effect of extending the lifespan of the infrared imaging device 4 that takes thermal images and enabling highly accurate position correction for thermal displacement of the machine tool 3. 【0060】 The control unit 15 instructs the infrared imaging device 4 to perform shutter calibration when the machine tool 3 reaches a predetermined state before starting machining. This allows the control device 2A to estimate the amount of thermal displacement based on the thermal image when the machine tool 3 reaches the specified state. 【0061】 When the coordinate system of the workpiece to be processed by the machine tool 3, or the coordinate system of the tool used to process the workpiece, is set, the control unit 15 instructs the infrared imaging device 4 to perform shutter calibration. This allows the control device 2A to acquire a thermal image at the time origin and estimate the amount of thermal displacement. 【0062】 The control unit 15 instructs the infrared imaging device 4 to perform shutter calibration when the movable part moves to a predetermined position. This allows the control device 2A to estimate the amount of thermal displacement based on the thermal image when the movable part is in the predetermined position. 【0063】 Embodiment 2. Embodiment 2 describes an example in which the timing of shutter calibration is determined based on the temperature of the infrared imaging device 4. In Embodiment 2, the same reference numerals are used for the same components as in Embodiment 1, and the description mainly focuses on configurations that differ from Embodiment 1. 【0064】Figure 8 shows an example of the configuration of the machining system 1B according to Embodiment 2. The machining system 1B is a system that performs machining using a machine tool 3. The machining system 1B comprises a control device 2B, a machine tool 3, and an infrared imaging device 4. The control device 2B controls the machine tool 3. The control device 2B also functions as a position correction device that corrects the position of the movable parts of the machine tool 3. 【0065】 The control device 2B has the same configuration as the control device 2A shown in Figure 1. The control device 2B also includes a determination unit 20. The determination unit 20 determines whether or not to perform shutter calibration based on the result of measuring the temperature of the infrared imaging device 4. 【0066】 In Embodiment 2, the infrared imaging device 4 captures a thermal image of the machine tool 3, as in Embodiment 1, and transmits the thermal image to the control device 2B. The infrared imaging device 4 also sends temperature information output by the temperature sensor 49 provided in the infrared imaging device 4 to the control device 2B. The acquisition unit 10 acquires the thermal image from the infrared imaging device 4 and temperature information indicating the temperature of the infrared imaging device 4. 【0067】 Figure 9 shows an example of the configuration of the infrared imaging device 4 in the processing system 1B according to Embodiment 2. Figure 9 shows a part of the configuration of the infrared imaging device 4 shown in Figure 3 and the control device 2B. The readout circuit 50 is mounted on the readout circuit board 46 shown in Figure 3. The drive processing circuit 51 is mounted on the drive processing circuit board 47 shown in Figure 3. 【0068】 When a control signal instructing the capture of a thermal image is sent from the control device 2B to the infrared imaging device 4, the control signal is input to the drive processing circuit 51. The drive processing circuit 51 drives the infrared image sensor 45 according to the control signal. The infrared image sensor 45 captures the incident infrared energy. The infrared image sensor 45 detects the incident energy captured by the infrared imaging device 4. The readout circuit 50 reads the signal from the infrared image sensor 45 and outputs the readout signal to the drive processing circuit 51. The drive processing circuit 51 processes the signal from the readout circuit 50 and outputs a signal indicating a thermal image. The signal indicating a thermal image is sent to the control device 2B. 【0069】 The temperature sensor 49 measures the temperature. The temperature sensor 49 outputs temperature information indicating the measured temperature to the drive processing circuit 51. The temperature information is sent from the drive processing circuit 51 to the control device 2B. 【0070】 The acquisition unit 10 shown in Figure 8 acquires temperature information from the infrared imaging device 4 and outputs the acquired temperature information to the determination unit 20. The determination unit 20 determines whether or not to perform shutter calibration based on the temperature information. 【0071】 If the determination unit 20 determines that shutter calibration should be performed, it outputs information to the control unit 15 indicating that shutter calibration should be performed. The control unit 15 instructs the infrared imaging device 4 to perform shutter calibration by sending a control signal. In this way, the control unit 15 determines the timing for performing shutter calibration based on the determination by the determination unit 20, that is, based on the temperature measurement result from the temperature sensor 49. 【0072】 Next, the timing of when the infrared imaging device 4 performs shutter calibration will be explained. In one example, the control unit 15 causes the infrared imaging device 4 to perform shutter calibration when the temperature detected by the temperature sensor 49 converges within a specified range. The specified range is, for example, a range of ±0.5°C centered on a certain temperature. The temperature considered to be the center of the specified range is set based on the temperature change indicated in the temperature information. Alternatively, the temperature considered to be the center of the specified range may be a preset temperature. 【0073】The control unit 15 instructs the infrared imaging device 4 to take a thermal image immediately after shutter calibration. The control device 2B can perform shutter calibration and acquire a thermal image after the temperature of the infrared imaging device 4 has converged. This allows the control device 2B to estimate the amount of thermal displacement with high accuracy. Furthermore, by not performing shutter calibration before the temperature of the infrared imaging device 4 has converged, the control device 2B can reduce the number of shutter calibrations. This makes it possible to extend the lifespan of the infrared imaging device 4. 【0074】 The control device 2B may, after shutter calibration has been performed as described above, initiate the capture of a thermal image without performing shutter calibration. For example, the control device 2B may initiate the capture of a thermal image without performing shutter calibration if the temperature detected by the temperature sensor 49 is within the specified range. The control unit 15 stops the shutter calibration after it has been performed if the temperature indicated in the temperature information is within the set range. In this case, the control device 2B may initiate the capture of a thermal image periodically. By acquiring a thermal image when the temperature of the infrared imaging device 4 is converging, the control device 2B can estimate the amount of thermal displacement with high accuracy. Furthermore, by reducing the frequency of shutter calibration, the lifespan of the infrared imaging device 4 can be extended. 【0075】In the above configuration, the determination unit 20 determines whether or not to perform shutter calibration based on the temperature information output by the temperature sensor 49. Alternatively, the determination unit 20 may determine to perform shutter calibration when a predetermined time has elapsed since the infrared imaging device 4 was powered on, assuming that the temperature of the infrared imaging device 4 has converged. The determination unit 20 acquires a signal indicating that the infrared imaging device 4 has been powered on, and measures the time elapsed since the acquisition of the signal to determine whether or not a predetermined time has elapsed since the infrared imaging device 4 was powered on. If the determination unit 20 determines that a predetermined time has elapsed since the infrared imaging device 4 was powered on, it outputs information to the control unit 15 indicating that shutter calibration should be performed. In this way, the control unit 15 instructs the infrared imaging device 4 to perform shutter calibration when a predetermined time has elapsed since the infrared imaging device 4 was powered on. In this case as well, the control device 2B can estimate the amount of thermal displacement with high accuracy and extend the lifespan of the infrared imaging device 4. 【0076】 Furthermore, the control unit 15 may also perform shutter calibration if, as described in Embodiment 1, the machine tool 3 reaches a predetermined state before starting machining, and the determination unit 20 determines that shutter calibration should be performed. 【0077】 In the above configuration, the control unit 15 stops the shutter calibration if the temperature indicated in the temperature information is within the set range after the shutter calibration has been performed. In this case, the control unit 15 may also perform the shutter calibration if the temperature indicated in the temperature information falls outside the set range. The control device 2B can once again estimate the amount of thermal displacement with high accuracy by performing the shutter calibration when the temperature change of the infrared imaging device 4 exceeds the set range. The control device 2B may also output an alarm when the temperature change of the infrared imaging device 4 exceeds the set range. 【0078】 According to Embodiment 2, the control unit 15 determines the timing of shutter calibration based on the temperature measurement result from the temperature sensor 49 installed in the infrared imaging device 4. As a result, the control device 2B can perform shutter calibration when the temperature of the infrared imaging device 4 has stabilized and acquire a thermal image. Furthermore, it becomes possible to reduce the number of shutter calibrations, thereby extending the lifespan of the infrared imaging device 4. 【0079】 The control unit 15 stops the shutter calibration after it has been performed if the temperature indicated in the temperature information is within the set range. This allows the control device 2B to extend the lifespan of the infrared imaging device 4. 【0080】 The control unit 15 instructs the infrared imaging device 4 to perform shutter calibration after a predetermined time has elapsed since the infrared imaging device 4 was powered on. This allows the control unit 2B to perform shutter calibration when the temperature of the infrared imaging device 4 has stabilized, thereby acquiring a thermal image. Furthermore, it becomes possible to reduce the number of shutter calibrations, thereby extending the lifespan of the infrared imaging device 4. 【0081】 Embodiment 3. Embodiment 3 describes an example in which the amount of thermal displacement is estimated based on temperature data extracted from a portion of the multiple pixels constituting the thermal image, rather than based on temperature data extracted from the entire thermal image acquired by the infrared imaging device 4. 【0082】 The operation described in Embodiment 3 can be realized with the same configuration as the control device 2A shown in Figure 1, or the same configuration as the control device 2B shown in Figure 8. Below, the operation of Embodiment 3 will be described using the same configuration as the control device 2A as an example. Note that explanations that overlap with Embodiments 1 or 2 will be omitted. 【0083】In Embodiment 3, the preprocessing unit 12 extracts temperature data from a portion of the multiple pixels that make up the thermal image. The thermal displacement estimation unit 13 estimates the amount of thermal displacement based on the temperature data extracted from a portion of the multiple pixels that make up the thermal image. 【0084】 As one example, the preprocessor 12 sets multiple main measurement points on the machine tool 3 and determines each main measurement point and one or more surrounding points as peripheral measurement points to be used to extract temperature data. Any points can be set as main measurement points. For example, points that exhibit characteristics in the thermal image, or points with a higher temperature than their surroundings, can be set as main measurement points. The preprocessor 12 extracts temperature data from the pixels corresponding to each main measurement point and each peripheral measurement point. In this way, the preprocessor 12 extracts temperature data from a portion of the multiple pixels that make up the thermal image. 【0085】 The thermal displacement estimation unit 13 determines the temperature gradient between each main measurement point and surrounding measurement points, and estimates the amount of thermal displacement based on the determined temperature gradient. Alternatively, the thermal displacement estimation unit 13 determines a function that shows the relationship between position and temperature in the two-dimensional direction shown in the thermal image, based on the temperature of each main measurement point and the temperature of each surrounding measurement point, and obtains the temperature of one or more arbitrary points based on the determined function. The thermal displacement estimation unit 13 estimates the amount of thermal displacement based on the obtained temperatures. 【0086】 According to Embodiment 3, the thermal displacement estimation unit 13 estimates the amount of thermal displacement based on temperature data extracted from a portion of the multiple pixels constituting the thermal image. This allows the control device 2A to reduce computational resources compared to when temperature data is extracted from all pixels of the thermal image. The control device 2A can estimate the amount of thermal displacement with less computation. 【0087】Embodiment 4. Embodiment 4 describes an example in which the internal temperature distribution, which is the temperature distribution in the direction toward the interior of the machine tool 3, is estimated, and the amount of thermal displacement of the machine tool 3 is estimated based on the thermal image and the estimated internal temperature distribution. In Embodiment 4, the same reference numerals are used for the same components as in Embodiments 1 to 3 described above, and the description mainly focuses on configurations that differ from Embodiments 1 to 3. 【0088】 Figure 10 shows an example of the configuration of a machining system 1C according to Embodiment 4. The machining system 1C is a system that performs machining using a machine tool 3. The machining system 1C comprises a control device 2C, a machine tool 3, and an infrared imaging device 4. The control device 2C controls the machine tool 3. The control device 2C also functions as a position correction device that corrects the position of the movable parts of the machine tool 3. 【0089】 The control device 2C has the same configuration as the control device 2A shown in Figure 1. The control device 2C also includes an internal temperature estimation unit 21. The internal temperature estimation unit 21 estimates the internal temperature distribution based on temperature data extracted from the thermal image. 【0090】 Figure 11 is a diagram illustrating the estimation of internal temperature by the internal temperature estimation unit 21 of the control device 2C according to Embodiment 4. Figure 11 shows a machine tool 3 and an infrared imaging device 4. Inside the machine tool 3, there is an internal temperature sensor 61 that measures the internal temperature of the machine tool 3. Figure 11 schematically shows the internal temperature sensor 61. 【0091】 The preprocessor 12 sets an arbitrary number of main measurement points on the machine tool 3. The main measurement points are points on the surface of the machine tool 3 that are captured by the infrared imaging device 4. Any points can be set as main measurement points. The preprocessor 12 extracts temperature data from pixels corresponding to the main measurement points. In this way, the preprocessor 12 extracts temperature data from a portion of the multiple pixels that make up the thermal image. 【0092】The internal temperature estimation unit 21 acquires temperature data extracted by the preprocessing unit 12 from the preprocessing unit 12. The internal temperature estimation unit 21 acquires internal temperature information indicating the temperature measured by the internal temperature sensor 61. Based on the temperature of the main measurement points and their transient response values, and the temperature indicated in the internal temperature information, the internal temperature estimation unit 21 calculates the amount of heat transferred between the main measurement points and the measurement points of the internal temperature sensor 61. Based on the calculated amount of heat transferred, the internal temperature estimation unit 21 creates a function for the temperature at each position in the direction from the main measurement points toward the measurement points of the internal temperature sensor 61. As a result, the internal temperature estimation unit 21 calculates the temperature distribution in the direction from the main measurement points toward the interior of the machine tool 3. 【0093】 The method by which the internal temperature estimation unit 21 calculates the temperature distribution is arbitrary. The internal temperature estimation unit 21 may, for example, calculate the temperature distribution using a model that demonstrates Fourier's law. Alternatively, the internal temperature estimation unit 21 may calculate the temperature distribution using a three-dimensional finite element method or a one-dimensional finite element method. 【0094】 The internal temperature estimation unit 21 outputs the temperature distribution calculation result to the learning unit 17. The learning unit 17 learns the relationship between the temperature distribution of the machine tool 3 and the amount of thermal displacement of the machine tool 3 and generates a model. The model holding unit 18 holds the model generated by the learning unit 17. The thermal displacement estimation unit 13 reads the model from the model holding unit 18 and estimates the amount of thermal displacement of the machine tool 3 by inputting temperature data extracted from the thermal image into the model. As a result, the thermal displacement estimation unit 13 estimates the amount of thermal displacement of the machine tool 3 based on the thermal image and the estimated internal temperature distribution. 【0095】 According to Embodiment 4, the control device 2C includes an internal temperature estimation unit 21 that estimates the internal temperature distribution, which is the temperature distribution in the direction toward the interior of the machine tool 3, based on temperature data extracted from the thermal image, and a thermal displacement estimation unit 13 that estimates the amount of thermal displacement of the machine tool 3 based on the thermal image and the estimated internal temperature distribution. As a result, the control device 2C can estimate the amount of thermal displacement with high accuracy. 【0096】Embodiment 5. Embodiment 5 describes an example of estimating the internal temperature distribution based on equipment data indicating the state of equipment owned by the machine tool 3 or equipment attached to the machine tool 3. In Embodiment 5, the same reference numerals are used for the same components as in Embodiments 1 to 4, and the description will mainly focus on configurations that differ from Embodiments 1 to 4. 【0097】 Figure 12 shows an example of the configuration of a machining system 1D according to Embodiment 5. The machining system 1D is a system that performs machining using a machine tool 3. The machining system 1D comprises a control device 2D, a machine tool 3, an infrared imaging device 4, and peripheral equipment 6. The control device 2D controls the machine tool 3. The control device 2D also functions as a position correction device that corrects the position of the movable parts of the machine tool 3. The control device 2D has the same configuration as the control device 2C shown in Figure 10. 【0098】 Peripheral equipment 6 is equipment that is part of the machine tool 3, or equipment that is attached to the machine tool 3. In the example shown in Figure 12, peripheral equipment 6 is equipment that is attached to the machine tool 3. 【0099】 One example of peripheral equipment 6 is a chiller installed on the machine tool 3. Peripheral equipment 6 outputs equipment data, which is information indicating the temperature of the cooling pipes that make up the chiller, to the control device 2D. The equipment data is acquired by the acquisition unit 10 and recorded in the recording unit 11. The pre-processing unit 12 outputs the equipment data read from the recording unit 11 to the internal temperature estimation unit 21. 【0100】 Figure 13 is a diagram illustrating the estimation of internal temperature by the internal temperature estimation unit 21 of the control device 2D according to Embodiment 5. Figure 13 shows a machine tool 3 and an infrared imaging device 4. Cooling pipes 62 are provided inside the machine tool 3. Figure 13 schematically shows the cooling pipes 62. 【0101】 The preprocessor unit 12 sets an arbitrary number of main measurement points on the machine tool 3. The preprocessor unit 12 extracts temperature data from pixels corresponding to the main measurement points. In this way, the preprocessor unit 12 extracts temperature data from a portion of the multiple pixels that make up the thermal image. 【0102】 The internal temperature estimation unit 21 acquires temperature data and equipment data from the preprocessing unit 12. Based on the temperature of the main measurement points and their transient response values, and the temperature shown in the equipment data, the internal temperature estimation unit 21 calculates the amount of heat transferred between the main measurement points and the cooling pipes 62. The internal temperature estimation unit 21 calculates the temperature distribution in the direction from the main measurement points toward the interior of the machine tool 3. The method by which the internal temperature estimation unit 21 calculates the temperature distribution is the same as in Embodiment 4. 【0103】 In the above, the internal temperature distribution is estimated based on equipment data indicating the internal temperature of the machine tool 3. The equipment data may be other than data indicating the internal temperature of the machine tool 3. Peripheral equipment 6 may be a motor such as the spindle motor or servo motor of the machine tool 3, or equipment such as an amplifier that drives the motor. The equipment data may be data indicating the driving state of these. Equipment data obtained from the motor may be data indicating the motor's output. Equipment data obtained from the amplifier may be data indicating the amplifier's output. 【0104】 For example, information showing the relationship between the motor output and the internal temperature is pre-recorded in the recording unit 11. The internal temperature estimation unit 21 can estimate the internal temperature from the motor output based on the information recorded in the recording unit 11. The internal temperature estimation unit 21 calculates the amount of heat transferred between the main measurement points and the cooling pipes 62 based on the temperature of the main measurement points and their transient response values, and the estimated internal temperature. As a result, the internal temperature estimation unit 21 calculates the temperature distribution in the direction from the main measurement points toward the interior of the machine tool 3. The same procedure applies when the equipment data is data indicating the output of the amplifier. 【0105】 Furthermore, peripheral equipment 6 is not limited to the equipment described above. Equipment data is not limited to the above, as it may be data relating to conditions that could affect the internal temperature of the machine tool 3. 【0106】According to Embodiment 5, the internal temperature estimation unit 21 estimates the internal temperature distribution based on temperature data and equipment data indicating the state of equipment on the machine tool 3 or equipment attached to the machine tool 3. As a result, the control device 2D can estimate the amount of thermal displacement with high accuracy even without the addition of the internal temperature sensor 61 shown in Figure 11. 【0107】 Next, the hardware configuration for realizing the control devices 2A, 2B, 2C, and 2D according to Embodiments 1 to 5 will be described. Figure 14 is a diagram showing an example of the hardware configuration for realizing the control devices 2A, 2B, 2C, and 2D according to Embodiments 1 to 5. The control devices 2A, 2B, 2C, and 2D are realized by a computer system comprising a processing circuit 70, an input unit 71, a display unit 74, and an output unit 75. The processing circuit 70 comprises a processor 72 and a memory 73. The processing circuit 70 is a circuit in which the processor 72 executes software. 【0108】 The functions of the preprocessing unit 12, thermal displacement estimation unit 13, correction amount generation unit 14, control unit 15, and learning unit 17, which are processing units of control devices 2A, 2B, 2C, and 2D, the functions of the determination unit 20, which is a processing unit of control device 2B, and the functions of the internal temperature estimation unit 21, which is a processing unit of control devices 2C and 2D, are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 73. 【0109】 The processing circuit 70 implements the processing units of the control devices 2A, 2B, 2C, and 2D by having the processor 72 read and execute a program stored in the memory 73. In other words, the processing circuit 70 includes a memory 73 for storing a program that will ultimately result in the execution of the processing of the control devices 2A, 2B, 2C, and 2D. The program stored in the memory 73 is a position correction program that causes the computer to execute the procedures and methods of processing for the control devices 2A, 2B, 2C, and 2D. 【0110】The functions of the recording unit 11 and model holding unit 18 of the control devices 2A, 2B, 2C, and 2D are realized by using the memory 73. The memory 73 is also used as temporary memory when the processor 72 performs various processes. The input unit 71 is an interface circuit that receives data from outside the control devices 2A, 2B, 2C, and 2D and provides it to the processor 72. The functions of the acquisition unit 10 of the control devices 2A, 2B, 2C, and 2D are realized by using the input unit 71. The output unit 75 is an interface circuit that sends data from the processor 72 or the memory 73 to the outside of the control devices 2A, 2B, 2C, and 2D. 【0111】 The processor 72 is a CPU (Central Processing Unit). The processor 72 may also be a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor). The memory 73 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM® (Electrically Erasable Programmable Read Only Memory), magnetic disk, flexible disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc). 【0112】 The display unit 74 is a display that shows information. The display unit 74 is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro-Luminescence) display. The functions of the display unit 16 of the control devices 2A, 2B, 2C, and 2D are realized by using the display unit 74. 【0113】The processing circuits 70 of the control devices 2A, 2B, 2C, and 2D may be dedicated circuits. Dedicated circuits include single circuits, composite circuits, programmed processors, parallel programmed processors, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), or circuits combining these. 【0114】 The position correction programs according to Embodiments 1 to 5 may be provided on a recording medium such as a CD (Compact Disc)-ROM or DVD-ROM. The position correction programs may also be provided by being stored on a computer connected to a network such as the Internet and downloaded via the Internet or other network. The position correction programs may also be provided or distributed via a network such as the Internet. 【0115】 In embodiments 1 to 5, the control devices 2A, 2B, 2C, and 2D that control the machine tool 3 are provided with the function of a position correction device. In embodiments 1 to 5, the position correction device may be implemented by a device separate from the control devices that control the machine tool 3. In this case, the position correction device can be implemented with a configuration similar to the hardware configuration shown in Figure 14. 【0116】 The configurations shown in each of the embodiments described above are examples of the content of this disclosure. The configurations of each embodiment can be combined with other known technologies. The configurations of each embodiment may be combined with each other as appropriate. It is possible to omit or modify parts of the configurations of each embodiment without departing from the gist of this disclosure. 【0117】1A, 1B, 1C, 1D Machining system, 2A, 2B, 2C, 2D Control device, 3 Machine tool, 4 Infrared imaging device, 6 Peripheral equipment, 10 Acquisition unit, 11 Recording unit, 12 Preprocessing unit, 13 Thermal displacement estimation unit, 14 Correction amount generation unit, 15 Control unit, 16, 74 Display unit, 17 Learning unit, 18 Model holding unit, 20 Judgment unit, 21 Internal temperature estimation unit, 30 Bed, 31 Column, 32 Table, 33 Head, 34 Spindle, 35 Workpiece, 36 Tool, 37X X-axis drive system, 37Y Y-axis drive system, 37Z Z-axis drive system, 41 Housing, 42 Lens barrel, 43 Connector, 44 Lens, 45 Infrared image sensor, 46 Readout circuit board, 47 Drive processing circuit board, 48 Shutter, 49 Temperature sensor, 50 Readout circuit, 51 Drive processing circuit, 61 Internal temperature sensor, 62 Cooling piping, 70 Processing circuit, 71 Input section, 72 Processor, 73 Memory, 75 Output section.

Claims

1. A position correction device comprising: a thermal displacement estimation unit that estimates the amount of thermal displacement of a machine tool having a movable part based on a thermal image taken by an infrared imaging device having an infrared image sensor and a shutter provided on the optical path of infrared rays incident to the infrared image sensor; a correction amount generation unit that generates a correction amount for the position of the movable part based on the estimated amount of thermal displacement; and a control unit that determines the timing for performing calibration involving taking images with the shutter closed and instructs the infrared imaging device to perform the calibration at the timing.

2. The position correction device according to claim 1, characterized in that the control unit instructs the infrared imaging device to perform the calibration when the machine tool reaches a predetermined state before starting machining.

3. The position correction device according to claim 2, characterized in that the control unit instructs the infrared imaging device to perform the calibration when the coordinate system of the workpiece processed by the machine tool or the coordinate system of the tool used to process the workpiece is set.

4. The position correction device according to claim 2, characterized in that the control unit instructs the infrared imaging device to perform the calibration when the movable part moves to a predetermined position.

5. The position correction device according to claim 1 or 2, characterized in that the control unit determines the timing based on temperature information indicating the temperature measured by a temperature sensor installed in the infrared imaging device.

6. The position correction device according to claim 5, characterized in that the control unit stops the calibration after the calibration has been performed if the temperature indicated in the temperature information is within the set range.

7. The position correction device according to claim 1 or 2, characterized in that the control unit instructs the infrared imaging device to perform the calibration when a predetermined time has elapsed since the power of the infrared imaging device was turned on.

8. The position correction device according to any one of claims 1 to 7, characterized in that the thermal displacement estimation unit estimates the amount of thermal displacement based on temperature data extracted from a portion of the plurality of pixels constituting the thermal image.

9. The position correction device according to any one of 1 to 7, comprising an internal temperature estimation unit that estimates an internal temperature distribution which is a temperature distribution toward the interior of the machine tool based on temperature data extracted from the thermal image, wherein the thermal displacement estimation unit estimates the amount of thermal displacement of the machine tool based on the thermal image and the estimated internal temperature distribution.

10. The position correction device according to claim 9, characterized in that the internal temperature estimation unit estimates the internal temperature distribution based on the temperature data and equipment data indicating the state of equipment owned by the machine tool or equipment attached to the machine tool.

11. A position correction program characterized by causing a computer system to perform the following steps: determine the timing for an infrared imaging device having an infrared image sensor and a shutter provided on the optical path of infrared rays incident to the infrared image sensor to perform calibration involving taking a photograph with the shutter closed, and instruct the infrared imaging device to perform the calibration at the timing; estimate the amount of thermal displacement of a machine tool having a movable part based on a thermal image taken of the machine tool by the infrared imaging device; and generate a correction amount for the position of the movable part based on the estimated amount of thermal displacement.

12. A position correction method for correcting the position of a movable part of a machine tool having a movable part using a computer system, comprising: determining the timing for an infrared imaging device having an infrared image sensor and a shutter provided on the optical path of infrared rays incident to the infrared image sensor to perform calibration with the shutter closed, and instructing the infrared imaging device to perform the calibration at the timing; estimating the amount of thermal displacement of the machine tool based on a thermal image of the machine tool taken by the infrared imaging device; and generating a correction amount for the position of the movable part based on the estimated amount of thermal displacement.

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