MACHINE CONTROL DEVICE

Abstract

Machine control device (10) that controls a machine performing a predetermined operation on an object (W), wherein the machine control device (10) is configured to control a relative position of the machine and the object (W) based on an image containing the object (W) captured by an imaging device (2), wherein the machine control device (10) includes: an imaging control unit (11) that controls the position and orientation of the imaging device (2) and controls the imaging device (2) to take two or more images including the object at two or more different imaging positions, based on a control command; an imaging position information acquisition unit (13) that acquires position information of the two or more imaging positions; a measurement distance recovery unit (14) which recovers a measurement distance of the object (W) as position information of the object (W) based on at least two images of the two or more images, distance information between at least two imaging positions corresponding to the at least two images of the two or more imaging positions, and a parameter of the imaging device, using a stereo camera method; a region specification unit (12) that specifies a partial region of the object (W) as a specified region; and a predetermined accuracy position calculation unit (17) which calculates distance information between the at least two imaging positions in which the measurement accuracy of the object (W) meets a predetermined accuracy, based on the at least two images, the measurement distance of the object (W) and the parameter of the imaging device (2), or a measurement distance of the object (W) in which the measurement accuracy of the object (W) meets a predetermined accuracy, based on the at least two images, the distance information between the at least two imaging positions and the parameter of the imaging device (2) in the specified range, wherein the machine control device (10) controls the position and orientation of the imaging device (2) based on the distance information between the at least two imaging positions or the measurement distance of the object (W) which is calculated by the predetermined accuracy position computation unit (17), and changes at least one of the at least two imaging positions.

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a machine control device that controls machine tools or machines such as industrial robots. State of the art

[0002] For example, there is a numerical control device of a machine tool that performs machining (predetermined processing) such as cutting on a workpiece (object) using a tool. In such a numerical control device, when controlling the relative position between the tool and the workpiece, it is expected to use information about the position and orientation of the workpiece based on an image of the workpiece captured by an image sensor (imaging device) (see, for example, Patent Document 1). See also Patent Document 2. Patent document 1: JP 2 889 011 B2 Patent document 2: DE 10 2015 226 696 A1 SUMMARY OF THE INVENTION

[0003] Compared to the machining precision of the machine tool's numerical control device, the measurement accuracy of the image sensor is low. Therefore, if the workpiece position and orientation information based on the image of the workpiece captured by the image sensor is used to position the workpiece without considering the measurement precision of the image sensor, a collision between the tool and the workpiece may occur, and the tool or workpiece may be damaged.

[0004] It is an object of the present invention to provide a machine control device for improving safety in a machine control device for controlling a machine based on an image of an object captured by an imaging device.

[0005] This object is achieved by a machine control device having the features of patent claim 1.

[0006] A machine control device according to a first aspect of the present invention is a machine control device (for example, a machine control device 10 described later) that controls a machine that performs a predetermined operation on an object (for example, a workpiece W described later), the machine control device being configured to control a relative position of the machine and the object based on an image including the object captured by the imaging device (for example, an image sensor 2 described later), the machine control device comprising: an imaging control unit (for example, an imaging control unit 11 described later) that controls a position and orientation of the imaging device and controls the imaging device to capture two or more images including the object at two or more different imaging positions,based on a control command; and an imaging position information acquisition unit (e.g., an imaging position information acquisition unit 13) that acquires position information of the two or more imaging positions; a measurement distance restoration unit (e.g., a measurement distance restoration unit 14) that restores a measurement distance of the object as position information of the object based on at least two images from the two or more images, distance information between at least two imaging positions corresponding to the at least two images from the two or more imaging positions, and a parameter of the imaging device using a stereo camera method; a region specification unit (e.g., a region specification unit 12) that specifies a partial region of the object as a specified region; and,

[0007] a predetermined accuracy position calculation unit (for example, a predetermined accuracy position calculation unit 17) that calculates distance information between the at least two imaging positions at which the measurement accuracy of the object satisfies a predetermined accuracy, based on the at least two images, the measurement distance of the object, and the parameter of the imaging device, or calculates a measurement distance of the object at which the measurement accuracy of the object satisfies a predetermined accuracy, based on the at least two images, the distance information between the at least two imaging positions, and the parameter of the imaging device in the specified range in which the machine control device controls the position and orientation of the imaging device, based on the distance information between the at least two imaging positions or the measurement distance of the object,which is calculated by the predetermined accuracy position calculation unit, and changes at least one of the at least two imaging positions.,

[0008] According to a second aspect of the present invention, in the machine control device as described in the first aspect, the measurement distance recovery unit may obtain parallax information Z for each pixel by performing range matching on the at least two images, and may calculate a measurement distance H of the object by equation (1) below based on the parallax information Z for each pixel, distance information between the at least two imaging positions D and the focal length f, which is a parameter of the imaging device, and the predetermined accuracy position calculation unit may calculate a distance D' between the at least two imaging positions, in which the measurement accuracy of the object satisfies a predetermined accuracy P', by equation (3) below based on the measurement distance H of the object and a focal length f, which is a parameter of the imaging device, or may calculate a measurement distance H' of the object,in which the measurement accuracy of the object satisfies the predetermined accuracy P', by equation (4) below, based on the distance between the at least two imaging positions D and the focal length f, which is the parameter of the imaging device, , H=D×f / Z P'=H2 / (D'×f) P'=H'2 / (D×f)

[0009] According to a third aspect of the present invention, the machine control device as described in the first aspect or the second aspect may control the position of the imaging device in a direction that increases a distance between the at least two imaging positions or in a direction that brings the two imaging positions close to the object, thereby improving the measurement accuracy of the object.

[0010] According to the present invention, it is possible to provide a machine control device for improving safety in a machine control device for controlling a machine based on an image of an object captured by an imaging device. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a main part of the machine control device of a machine tool according to a first embodiment as an embodiment of the present invention; Fig. 2 is a diagram for explaining the control of an image sensor by the machine control device; Fig. 3 is a diagram for explaining the restoration of a measurement distance of a workpiece using the stereo camera method; Fig. 4 is a diagram for explaining a calculation of two imaging positions (movement amounts) satisfying a target accuracy by the machine control device; Fig. 5 is a diagram showing an example of a program for controlling the image sensor by the machine control device (left part) and explanations thereof (right part); Fig. 6 is a diagram for explaining a calculation of two imaging positions (movement amounts) satisfying aiming accuracy by the machine control device according to a modification example; and Fig. 7 is a diagram showing an example of a program for controlling the image sensor by the engine control device according to a modification example (left part) and explanations thereof (right part). DETAILED DESCRIPTION OF THE INVENTION

[0011] An example of an embodiment of the present invention will be described below with reference to the accompanying drawings. It should be noted that the same reference numerals are applied to identical or corresponding portions of the respective drawings. (First embodiment)

[0012] Fig. 1 is a diagram showing a main part of a machine control device of a machine tool according to a first embodiment as an embodiment. Fig. The machine control device 10 shown in FIG. 1 is a numerical control device that controls a machine tool to perform a predetermined operation (for example, machining such as cutting) on ​​a workpiece (object) W. In such an operation, the machine control device 10 detects a position of the workpiece W based on an image including the workpiece W captured by an image sensor (vision sensor, imaging device) 2, and controls the relative position of a tool T and the workpiece W of the machine tool. For example, the machine control device 10 may control the position of the tool T of the machine tool, or alternatively, may control the position of the workpiece W. When the image sensor 2 is mounted near the tool T of the machine tool, the movement command of the tool T of the machine tool and the movement command of the image sensor 2 can be made identical.The control of the image sensor 2 by the machine control device 10 is described in detail below.

[0013] The machine control device 10 is configured, for example, by an arithmetic processor such as a CPU (central processing unit) and a DSP (digital signal processor). The various functions of the machine control device 10 are realized by executing predetermined software (programs, applications) stored, for example, in a memory unit. The various functions of the machine control device 10 can be realized through the cooperation of hardware and software, or can be realized solely by FPGA (field-programmable gate array) or hardware (electronic circuits).

[0014] The machine control device 10 includes an image control unit 11, an area specifying unit 12, an imaging position information acquiring unit 13, a measurement distance restoring unit 14, a measurement precision calculating unit 15, a measurement precision determining unit 16, and a predetermined accuracy position calculating unit 17.

[0015] Fig. 2 is a diagram for explaining the control of the image sensor 2 by the machine control device 10. As in Fig. 2, the image control unit 11 controls the position and orientation of the image sensor 2 and controls the image sensor 2 to capture two images including the workpiece W at two different imaging positions based, for example, on a control command stored in a storage unit (not shown). For example, the image control unit 11 causes the image sensor 2 to move in a predetermined direction and captures the workpiece W by the image sensor 2 at two imaging positions at a distance D between imaging positions (hereinafter also referred to as the inter-viewpoint distance).

[0016] In the two images, the area specifying unit 12 specifies a partial area of ​​a workpiece W as a specified area (hereinafter also referred to as a specified pixel or a pixel of interest). The specified area may be an area of ​​a workpiece manually specified by the user based on a captured image displayed on the display unit or the like, or may be an area of ​​a workpiece automatically specified by image processing of the captured image (for example, feature point extraction algorithms).

[0017] The imaging position information acquisition unit 13 acquires position information of the two imaging positions (e.g., XYZ coordinates in the camera coordinate system or the machine coordinate system) from the control command described above. It should be noted that the imaging position information acquisition unit 13 may acquire coordinates before and after the movement from the machine control device 10.

[0018] The measurement distance retrieval unit 14 restores the measurement distance of the workpiece W as the position information of the workpiece W based on the two images, the distance information between the two imaging positions, and the parameters of the image sensor 2 using the stereo camera method. Fig. Figure 3 is a diagram for explaining the recovery of the workpiece measurement distance using the stereo camera method. As shown in Fig. 3, the measurement distance recovery unit 14 determines the parallax for each pixel by performing area matching on the two images and calculates the measurement distance H of the workpiece W by the following equation (1) based on the parallax Z for each pixel, the distance between the two imaging positions D, and the focal length f, which is a parameter of the image sensor 2. H=D×f / Z

[0019] Here, the machine control device 10 detects the position of the workpiece W based on the image including the workpiece W captured by the image sensor 2, and controls the relative position between the tool T and the workpiece W of the machine tool.

[0020] Compared with the machining accuracy of the numerical control device of the machine tool, the measurement accuracy of the image sensor 2 is lower. Therefore, if the information on the position and orientation of the workpiece W based on the image of the workpiece W captured by the image sensor 2 is used for, for example, the position of the workpiece W without considering the measurement accuracy of the image sensor 2, a collision between the tool T and the workpiece W may occur, and the tool T or the workpiece W may be damaged. Therefore, the machine control device 10 of the present embodiment includes the measurement precision calculation unit 15, the measurement precision determination unit 16, and the predetermined accuracy position calculation unit 17, in addition to the measurement distance recovery unit 14.

[0021] The measurement precision calculation unit 15 calculates the measurement accuracy P of the measurement distance of the workpiece W based on the two images, the distance information between the two imaging positions, and the parameters of the image sensor 2 using the stereo camera method. The measurement accuracy P is defined by how much difference occurs when assuming that the workpiece W displayed on a photographing surface is erroneously displayed on the adjacent pixel (the parallax at this time is defined as Z') (see Equation (2) below). In other words, the measurement accuracy P is a value obtained by subtracting the measurement distance H by Z. P=|H(Z')|=|dH / dZ|=D×f / Z2

[0022] The above equation (1) is inserted into it and the measurement accuracy P is represented by the following equation (2). P=H2 / (D×f)

[0023] From this, it can be seen that the measurement accuracy P is smaller when the distance between the two imaging positions D is larger, and thus the accuracy is high.

[0024] The measurement precision determination unit 16 determines whether the measurement accuracy P of the workpiece W satisfies the target accuracy P' (predetermined accuracy, hereinafter referred to as specified accuracy) within the specified range. The target accuracy P' may be a predetermined value and may be stored in a storage unit or the like.

[0025] The predetermined accuracy position calculation unit 17 calculates two imaging positions where the measurement accuracy P of the workpiece W satisfies the target accuracy P'. For example, the predetermined accuracy position calculation unit 17 calculates two image positions where the measurement accuracy P of the workpiece W satisfies the target accuracy P' based on the two images and the parameters of the image sensor 2. More specifically, the predetermined accuracy position calculation unit 17 calculates distance information between two imaging positions where the measurement accuracy of the workpiece W satisfies a predetermined accuracy based on the two images, the measurement distance of the workpiece W, and the parameters of the image sensor 2 within the specified range.

[0026] Fig. 4 is a diagram for explaining the calculation of two imaging positions (movement amounts) that satisfy the target accuracy P' by the machine control device 10. For example, the predetermined accuracy position calculation unit 17 calculates the distance between two imaging positions D' at which the measurement accuracy of the workpiece W satisfies the predetermined accuracy P' by the following equation (3) based on the measurement distance H of the workpiece W and the focal length f, which is a parameter of the imaging device. P'=H2 / (D'×f)

[0027] Thus, the movement distance E from the state of the intermediate viewpoint distance D is determined by the following equation E=D'=D

[0028] Alternatively, the predetermined accuracy position calculation unit 17 may calculate the measurement distance of the workpiece W at which the measurement accuracy of the workpiece W satisfies a predetermined accuracy based on the two images, the distance information between the two imaging positions, and the parameters of the image sensor 2 within the specified range. For example, the predetermined accuracy position calculation unit 17 may calculate the measurement distance H' of the workpiece W at which the measurement accuracy of the workpiece W satisfies the predetermined accuracy P' by the following equation (4) based on the distance between the two imaging positions D and the focal length f, which is a parameter of the image sensor 2. P'=H'2 / (D×f)

[0029] As described above, the measurement accuracy is improved by increasing the inter-viewpoint distance D. Alternatively, the measurement accuracy is improved by making the inter-viewpoint distance D constant and bringing the image sensor 2 close to the workpiece W.

[0030] When the measurement accuracy of the workpiece W satisfies the target accuracy, the machine control device 10 controls the relative position of the tool T and the workpiece W of the machine tool based on the position information of the workpiece W calculated by the measurement distance recovery unit 14, and performs a predetermined operation on the workpiece W using the tool T.

[0031] On the other hand, if the measurement accuracy of the workpiece W does not satisfy the target accuracy, the machine control device 10 performs the following processing based on the two imaging positions satisfying the target accuracy P calculated by the predetermined accuracy position calculation unit 17: - movement and recording by the image sensor 2 according to the image control unit 11; - Calculating the position of the workpiece W by the area specifying unit 12, the imaging position information acquiring unit 13, and the measurement distance restoring unit 14; and - Calculation and determination of the measurement accuracy of the workpiece W by the precision calculation unit 15 and the precision determination unit 16.

[0032] If the measurement accuracy of the workpiece W does not meet the target accuracy, the machine control device 10 may repeat the following processing until the target accuracy is determined: - Calculating two imaging positions that satisfy the target accuracy P' by the predetermined accuracy position calculation unit 17; - movement and recording by the image sensor 2 according to the image control unit 11; - Calculating the position of the workpiece W by the area specifying unit 12, the imaging position information acquiring unit 13, and the measurement distance restoring unit 14; and - Calculation and determination of the measurement accuracy of the workpiece W by the precision calculation unit 15 and the precision determination unit 16.

[0033] When the aiming accuracy cannot be obtained even by repeating the above-described processing a predetermined number of times, or when it is difficult to move the image sensor 2, the machine control device 10 stops controlling the relative position of the tool T of the machine tool and the workpiece W based on the position information of the workpiece W calculated by the measurement distance recovery unit 14 and the predetermined operation of the workpiece W using the tool T.

[0034] Fig. 5 is a diagram showing an example of a program for controlling the image sensor 2 by the machine control device 10 (left part) and explanations thereof (right part). "G800" is a movement command of the image sensor. "G810" is a command to start imaging and image processing (measurement of position information and accuracy information). As a result, the image control unit 11 causes the image sensor 2 to move in a predetermined direction and performs imaging of the workpiece W through the image sensor 2 at two imaging positions of the distance between imaging positions (inter-viewpoint distance) D. The imaging position information acquisition unit 13 acquires two imaging positions from the control command.

[0035] "G820" is a command for specifying a pixel of interest (specified area). As a result, the area specifying unit 12 specifies a partial area of ​​a workpiece W as a specified area in two images. The column and row of a specified pixel are input as #100 and #101. The measurement distance retrieval unit 14 recovers the measurement distance of the workpiece W as the position information of the workpiece W based on the two images, the distance information between the two imaging positions, and the parameters of the image sensor 2 using the stereo camera method. The measurement precision calculation unit 15 calculates the measurement accuracy of the measurement distance of the workpiece W based on the two images, the distance information between the two imaging positions, and the parameters of the image sensor 2.

[0036] "G830" is a command for determining whether the position information of the workpiece W corresponding to pixels (#100, #101) satisfies (0.1, 0.1, 0.1) mm accuracy. As a result, the measurement precision determination unit 16 determines whether the measurement accuracy P of the workpiece W satisfies the target accuracy P' within the specified range. For example, the measurement precision determination unit 16 determines whether the measurement data of the pixel in column #100 and row #101 of the image satisfies (0.1, 0.1, 0.1) mm accuracy. If it does not satisfy, a number other than 0 is input to #8998.

[0037] "G840" is a command for calculating the imaging position required for the target pixel (specified area) to meet the specified accuracy (target accuracy). As a result, the predetermined accuracy position calculation unit 17 calculates two imaging positions at which the measurement accuracy P of the workpiece W satisfies the target accuracy P' (the distance between the two imaging positions D' or measurement distance H' of the workpiece W). For example, the predetermined accuracy position calculation unit 17 calculates the imaging position required for the measurement data of the pixel specified by column #100 and row #101 to meet the specified accuracy, and sets the next movement distance to X direction #300, Y direction #301, and Z direction #303.

[0038] Processing returns to the second line through the “GOTO 10” command and the image sensor is moved once again to perform imaging.

[0039] As described above, according to the machine control device 10 of the present embodiment, it is possible to improve the measurement accuracy of the workpiece W and improve the safety of the machine control device that controls the machine tool based on the image of the workpiece W captured by the image sensor 2. Furthermore, according to the machine control device 10 of the present embodiment, even when erroneous measurement or inability to measure occurs due to halo or occlusion, it also functions effectively.

[0040] According to the inventor of the present application, the following knowledge is obtained. - Existing image sensors cannot control measurement accuracy. - Measurement accuracy can be improved by bringing the image sensor close to the object; however, risks and limitations exist.

[0041] Sensors with high-resolution elements and high-precision lenses are expensive. - Currently, there is no way for the numerical control device to determine the measurement accuracy of the image sensor. There is also no way for the numerical control device to know the measurement accuracy of the image sensor.

[0042] There is no method for determining whether the accuracy required for machining is met. - Currently, there is no mechanism for the numerical control device to operate safely if the image sensor lacks accuracy. There is also no mechanism to stop the numerical control device from the image sensor. There is no mechanism to instruct the numerical control device to improve the image sensor's accuracy.

[0043] In these respects, the following advantages can be obtained by the engine control device 10 of the present embodiment. - The numerical control device is able to know the measurement accuracy of the image sensor. - The numerical control device makes it possible to determine whether the image sensor output value meets the specified accuracy or not. - The numerical control device is able to control (improve) the measurement accuracy of the image sensor. - If the measurement accuracy is insufficient, it is possible to stop the numerical control device. - Improve reliability

[0044] It is possible to guarantee the measurement accuracy of the image sensor required for processing.

[0045] It is possible to safely use the image sensors in a numerical control device. - Improvement of detection accuracy

[0046] It is possible to improve the measurement accuracy of the image sensor and the detection accuracy can be improved. - Reduction in equipment costs

[0047] It is possible to achieve functions equivalent to stereo cameras using a numerical control device + monocular camera + control software (programs). (Modification example)

[0048] In Fig. 1, the machine control device 10 may not be provided with the predetermined accuracy position calculation unit 17. In other words, the machine control device 10 may not perform the calculation of the two imaging positions that satisfy the target accuracy P' by the predetermined accuracy position calculation unit 17. In the modified example, when the measurement accuracy of the workpiece W does not satisfy the target accuracy, the machine control device 10 gradually expands the two imaging positions (for example, the distance between the two imaging positions D) until the target accuracy is obtained.

[0049] Fig. 6 is a diagram for explaining a calculation of two imaging positions (movement amounts) that satisfy the target accuracy by the machine control device 10 according to the modification example. As shown in Fig. As shown in FIG. 6, when the measurement accuracy of the workpiece W does not satisfy the target accuracy, the machine control device 10 according to the modification example expands the two imaging positions (for example, the distance between the two imaging positions D) by a predetermined amount (minimal amount) until the target accuracy is obtained. The predetermined amount (minimal amount) may be a predetermined amount and may be stored, for example, in a storage unit or the like. Alternatively, in the same manner as described above, the machine control device 10 according to the modification example may bring the two imaging positions (for example, the measurement distance H of the workpiece W) close to the workpiece W by a predetermined amount (minimal amount).

[0050] In other words, if the measurement accuracy of the workpiece W does not meet the target accuracy, the machine control device 10 of the modification example repeats the following processing until the target accuracy is obtained: - Changing the imaging position by a predetermined amount (tiny amount); - movement and recording by the image sensor 2 according to the image control unit 11; - Calculating the position of the workpiece W by the area specifying unit 12, the imaging position information acquiring unit 13, and the measurement distance restoring unit 14; and - Calculation and determination of the measurement accuracy of the workpiece W by the measurement precision calculation unit 15 and the measurement precision determination unit 16.

[0051] Fig. Fig. 7 is a diagram showing an example of a program for controlling the image sensor 2 by the machine control device 10 according to the modification example (left portion) and explanations thereof (right portion). Fig. The program shown in Figure 7 differs in the position of the “G800” from the one shown in Fig. 5 shown program.

[0052] "G800" is a motion command for the image sensor. For example, the image sensor is moved in the X direction by a predetermined distance (e.g., an initial value or a user specification) contained in #200.

[0053] Although embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and variations are possible. For example, in the above-described embodiment, the machine control device for measuring the position of the object based on an image including the object captured by the image sensor is exemplified; however, the present invention is not limited to this, and the present invention is applicable to a machine control device for measuring the position of an object based on an image including the object captured by various imaging devices. Examples of such various imaging devices include a monocular camera, a stereo camera capable of three-dimensional measurement, and a three-dimensional camera.Even with stereo cameras and three-dimensional cameras, measurement accuracy can be improved by bringing them close to the object.

[0054] Furthermore, in the embodiment described above, the machine control device for controlling the position with respect to the object based on two images containing the object captured at two imaging positions is exemplified; however, the present invention is not limited thereto, and the present invention is applicable to a machine control device for controlling the position with respect to the object based on three or more images containing the object captured at three or more imaging positions. In this case, it can be configured to determine the imaging position as a reference and can be configured to restore the measurement distance of the object as the position information of the object, as described above (the measurement distance restoration unit), calculate the measurement accuracy of the measurement distance of the object (the measurement accuracy calculation unit),to determine whether the measurement accuracy of the object satisfies a predetermined accuracy (the measurement accuracy determining unit), to calculate the distance information between the two imaging positions or the measurement distance of the object at which the measurement accuracy of the object satisfies a predetermined accuracy (predetermined accuracy calculating unit), to control the position and orientation of the imaging device based on the distance information between the two imaging positions or the measurement distance of the object calculated by the predetermined accuracy position calculating unit, and to change the imaging position with respect to the difference (the distance between the two imaging positions or the measurement distance of the object).

[0055] Furthermore, in the above-described embodiment, the numerical control device of the machine tool for performing a predetermined operation on a workpiece by controlling the relative position of a workpiece and a tool attached to the machine tool is exemplified. However, the present invention is not limited to this, and the present invention can be applied to various types of tool control devices, such as a robot control device for performing a predetermined operation on a workpiece by controlling the relative position of a workpiece and a tool or a hand attached to an industrial robot. In this case, when the imaging device is attached to the arm of the robot, the movement command of the arm of the robot and the movement command of the imaging device can be made identical. EXPLANATION OF REFERENCE SYMBOLS 2 Image sensor (imaging device) 10 Machine control device 11 Image control unit 12 Area specification unit 13 Imaging position information acquisition unit 14 Measuring distance recovery unit 15 Precision measurement computing unit 16 Measurement precision determination unit 17 Predetermined accuracy position calculation units

Claims

[1] A machine control device (10) that controls a machine that performs a predetermined operation on an object (W), the machine control device (10) being configured to control a relative position of the machine and the object (W) based on an image containing the object (W) captured by an imaging device (2), the machine control device (10) including: an imaging control unit (11) that controls a position and orientation of the imaging device (2) and controls the imaging device (2) to capture two or more images including the object at two or more different imaging positions based on a control command; an imaging position information acquiring unit (13) that acquires position information of the two or more imaging positions; a measurement distance restoration unit (14) that restores a measurement distance of the object (W) as position information of the object (W) based on at least two images from the two or more images, distance information between at least two imaging positions corresponding to the at least two images from the two or more imaging positions, and a parameter of the imaging device, using a stereo camera method; an area specifying unit (12) that specifies a partial area of ​​the object (W) as a specified area; and a predetermined accuracy position calculation unit (17) which calculates distance information between the at least two imaging positions in which the measurement accuracy of the object (W) satisfies a predetermined accuracy, based on the at least two images, the measurement distance of the object (W) and the parameter of the imaging device (2), or calculates a measurement distance of the object (W) at which the measurement accuracy of the object (W) satisfies a predetermined accuracy, based on the at least two images, the distance information between the at least two imaging positions and the parameter of the imaging device (2) in the specified range, wherein the machine control device (10) controls the position and orientation of the imaging device (2) based on the distance information between the at least two imaging positions or the measurement distance of the object (W) calculated by the predetermined accuracy position calculation unit (17), and changes at least one of the at least two imaging positions. [2] Machine control device (10) according to claim 1, wherein the measurement distance recovery unit (14) determines parallax information (Z) for each pixel by performing area matching on the at least two images, and calculates a measurement distance (H) of the object (W) by equation (1) below based on the parallax information (Z) for each pixel, distance information between the at least two imaging positions (D) and the focal length (f), which is a parameter of the imaging device (2), and the predetermined accuracy position calculation unit (17) calculates a distance (D') between the at least two imaging positions in which the measurement accuracy of the object (W) satisfies a predetermined accuracy (P') by equation (3) below, based on the measurement distance (H) of the object and a focal length (f), which is a parameter of the imaging device (2), or calculates a measurement distance (H') of the object (W) at which the measurement accuracy of the object (W) satisfies the predetermined accuracy (P') by a following equation (4), based on the distance between the at least two imaging positions (D) and the focal length (f), which is the parameter of the imaging device (2), H=D×f / Z P'=H2 / (D'×f) P'=H'2 / (D×f) [3] The machine control device (10) according to claim 1 or 2, wherein the machine control device (10) controls the position of the imaging device (2) in a direction that increases a distance between the at least two imaging positions or in a direction that brings the two imaging positions close to the object (W), thereby improving the measurement accuracy of the object (W).

Images