JP2010054283A - Device and method for measuring shape change - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring shape change for displaying the change of the shape of an observing object. <P>SOLUTION: A first observing device observes a measuring object mark, and acquires position information of the measuring object mark. An image output device outputs an image. A controller controls the first observing device and the image outputting device. The controller partitions an analytic model corresponding to the measuring object into a plurality of finite elements, stores the positions of nodes of the finite elements, stores the positions of a plurality of measuring object marks defined on the measuring object, acquires a time calendar of the position information of each measuring object mark from the first observing device, calculates the displacement of each node based on the time calendar of the position information acquired from the first observing device, and makes the image output device display the change in shape or attitude of the measuring object based on the displacement of each node. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shape change measurement apparatus and method for measuring displacement of a plurality of measurement object marks fixed to a measurement object and displaying a change in shape of the measurement object as an image based on a measurement result.

  Stereo measurement can be performed by imaging the same mark using two cameras (Patent Document 1). When performing general stereo measurement, the optical axes of the lenses of the two cameras are arranged in parallel to each other, and the positions of the principal points of the lenses of the two cameras are matched with respect to the optical axis direction. The position of the target mark can be detected by simultaneously imaging one target mark with two cameras.

JP 2003-242485 A

  In conventional stereo measurement, high accuracy is required for the position and orientation of the two cameras. In addition, since it is necessary to capture one mark with two cameras at the same time, the camera installation conditions during measurement are restricted. Although it is useful for measuring the position of a stationary mark, it is not suitable for measuring the time calendar of the displacement of the mark position.

According to one aspect of the invention,
A first observation device that observes the measurement target mark and obtains position information of the measurement target mark;
An image output device for outputting an image;
A control device for controlling the first observation device and the image output device;
The control device includes:
The analysis model corresponding to the measurement object is divided into a plurality of finite elements, and the positions of the nodes of the finite elements are stored.
Storing the positions of a plurality of measurement object marks defined on the measurement object;
Obtaining a time calendar of each position information of the measurement target mark when a mechanical action is given to the measurement target object from the first observation device;
Based on the time calendar of the position information acquired from the first observation device, to calculate the displacement of each of the nodes,
A shape change measuring device is provided that displays a change in the shape or posture of the measurement object on the image output device based on the displacement of each of the nodes.

According to another aspect of the invention,
Dividing the analysis model corresponding to the measurement object into a plurality of finite elements, and determining the positions of the nodes between the finite elements;
Measuring a time calendar of the position of a plurality of measurement object marks fixed to the measurement object;
Calculating a time calendar of displacement of each of the nodes based on a time calendar of the position of the measurement target mark;
And a step of displaying a change in shape of the measurement object as an image based on a time calendar of the displacement of each of the nodes.

  By calculating the displacement amount of the node from the actually observed displacement amount of the observation target mark, it is possible to display an image of the change in the shape of the observation target object. Thereby, the change of shape can be visually recognized easily.

  FIG. 1 shows a schematic diagram of a shape change measuring apparatus according to an embodiment. The measurement object 10 is arranged in a space in which an XYZ orthogonal coordinate system (global coordinate system) is defined. A plurality of measurement object marks A are fixed on the surface of the measurement object 10. The measurement target mark A may be formed by drawing directly on the surface of the measurement target 10, or a member on which the mark is formed may be attached to the surface of the measurement target 10.

  The measuring object 10 is deformed when an external force is applied. When the measurement object 10 is deformed, the measurement object mark A is displaced.

The first observation device 20 and the second observation device 30 observe the measurement target mark A. For the first observation device 20 and the second observation device 30, for example, a digital camera is used. When the observation object mark A is assigned a serial number from 1 to n, some of the observation object marks A _{1 to} A _i are observed by the first observation device 20, and the other observation object marks A _{i + 1 to An} are 2 observation devices 30. Incidentally, all the observation target marks _A 1 to A _n, may also be observed in both of the observation apparatus 20 and 30, part of the observation target mark _{A j ~A} j _{+ m} are both observation apparatus 20 And 30 may be observed.

  Each of the first observation device 20 and the second observation device 30 includes a lens and an image receiving surface. A first local coordinate system fixed to the first observation device 20 is defined, and a second local coordinate system fixed to the second observation device 30 is defined. The first local coordinate system is defined by a W axis that coincides with the optical axis of the lens of the first observation apparatus 20, a U axis and a V axis that are perpendicular to the W axis and orthogonal to each other. Matches the principal point of The image receiving surface is parallel to the UV surface. The second local coordinate system is defined by a T-axis that coincides with the optical axis of the lens of the second observation device 30, an R-axis and an S-axis that are perpendicular to the T-axis and orthogonal to each other, and the origin is the lens Matches the principal point of The image receiving surface is parallel to the RS surface.

  Image data captured by the first observation device 20 and the second observation device 30 are input to the processing device 40. The processing device 40 processes the input image data and obtains a time calendar of the shape change of the observation object 10. The time calendar of the shape change is displayed on the image display device 41 as an image.

  FIG. 2 shows a flowchart of the shape change measuring method according to the embodiment. First, in step SA1, the shape of the measurement object is defined using CAD. The shape of the measurement object is defined in the CAD coordinate system.

  In step SA2, a global coordinate system (XYZ coordinate system) associated with the CAD coordinate system is defined. Usually, the CAD coordinate system may be adopted as the global coordinate system.

  In step SA3, the measurement object defined by CAD is virtually divided into a plurality of finite elements.

  FIG. 3 shows the measurement object 10 divided into finite elements. A plurality of measurement object marks A are fixed to the surface of the measurement object 10. FIG. 3 shows an example in which the measurement object 10 is divided into a large number of cubic elements. A node B is defined at the vertex of each element. Each element may have an arbitrary three-dimensional shape having a polygonal surface. In this case, the vertex of the polygonal surface is the node B. The control device 40 stores the position of each node B in the global coordinate system.

  In step SA4, the position of the measurement target mark A attached to the actual measurement object 10 in the global coordinate system is stored in the control device 40.

  In step SA5, the first observation device 20 and the second observation device 30 are arranged and fixed in the space in which the global coordinate system is defined. The control device 40 stores the positions and orientations of the first observation device 20 and the second observation device 30 in the global coordinate system. The position of the first observation device 20 is specified by the global coordinates of the principal point of the lens. The attitude of the first observation device 20 is specified by the optical axis of the lens, that is, the direction of the W axis and the direction of the U axis. Similarly, the position of the second observation device 30 is specified by the global coordinates of the principal point of the lens, and the posture is specified by the directions of the T axis and the R axis.

  In the embodiment, the W axis of the first local coordinate system fixed to the first observation device 20 is parallel to the Z axis of the global coordinate system, and the second local coordinate system fixed to the second observation device 30 is used. The first and second observation devices 20 and 30 are arranged so that the T axis of the coordinate system is parallel to the X axis of the global coordinate system. In this arrangement, the first observation device 20 observes the displacement in the direction orthogonal to the W axis, that is, the XY in-plane direction, and the second observation device 30 is in the direction orthogonal to the T axis, that is, in the YZ plane. Directional displacement can be observed.

  It is preferable to arrange the first and second observation devices 20 and 30 according to the deformation expected for the observation object 10. For example, if the direction of the external force is parallel to the XY plane and the magnitude thereof is substantially constant with respect to the Z direction, the deformation of the measurement object 10 is predicted to occur in a direction substantially parallel to the XY plane. This deformation can be observed mainly by the first observation device 20.

  In the following description, a case will be described in which the observation object 10 is predicted to deform mainly in a direction parallel to the XY plane.

  In step SA6, the observation object mark A is imaged by the first observation apparatus 20 and the second observation apparatus 30 while applying an external force to the measurement object 10. The captured image data is input to the control device 40. The control device 40 measures the position of the image of the observation target mark A in the image receiving plane by performing image analysis. In the following steps, processing of image data acquired by the first observation apparatus 20 will be described. Processing of the image data acquired by the second observation apparatus 30 is performed in the same manner.

The image receiving plane of the first observation apparatus 20 is parallel to the UV plane of the first local coordinate system. For this reason, the position in the image receiving surface is specified by the U coordinate and the V coordinate. By analyzing the image data at the observation times t ₀ , t ₁ , t ₂ ..., The position of the observation target mark A at the observation time, that is, the (U, V) coordinates, is detected. Hereinafter, an example of a method of detecting the position of the observation target marks A _1.

First, from the image data, cut out a rectangular region including the observation target marks A _1. The (U, V) coordinates of the clipped area, for example, the (U, V) coordinates of one vertex of the rectangle are stored. The cut image data is subjected to processing such as a low-pass filter or contraction / expansion operation for the purpose of noise removal. Using the image data from which noise is removed, detecting a position of the observation target marks A ₁ in cropped area.

  For the detection of the mark position, it is preferable to use the center of gravity calculation or the peak value detection method. Since the mark image may be blurred, position detection by the edge detection method or pattern matching method is not suitable. By setting a threshold value for the light intensity and performing the centroid calculation only for pixels that are equal to or greater than the threshold value, it is possible to make it less susceptible to the influence of the background light intensity.

Position of the cropped area, and the cut position of the observation target marks A ₁ in the region, it is possible to calculate the observation target marks A ₁ of (U, V) coordinates in the image receiving plane. In a similar way, determine the (U, V) coordinates of another observation target mark _A 2 to A _n.

As shown in FIG. 4, a time calendar table of coordinates and displacement amounts is prepared for each of the observation target marks A ₁ , A ₂ . In this time calendar table, an area for storing (U, V) coordinates and displacement amounts (ΔU, ΔV) is secured for each time. The obtained (U, V) coordinate values are stored in the (U, V) coordinate storage area of the time calendar table shown in FIG.

In step SA7, the displacement at each observation time is calculated for each observation target mark A from the time calendar in the image receiving plane of each observation target mark A. For example, when the positions of the observation target mark A _{1 at} the times t ₀ and t ₁ are (U ₁₀ , V ₁₀ ) and (U ₁₁ , V ₁₁ ), the displacement (ΔU of the observation target mark A _{1 at} the observation time t _{1 11} , ΔV ₁₁ ) becomes (U ₁₁ −U ₁₀ , V ₁₁ −V ₁₀ ). The displacement amounts (ΔU, ΔV) obtained by calculation are stored in the displacement amount storage area of the time calendar table shown in FIG.

  Next, the displacement amount at a plurality of points (extraction points) extracted on the (U, V) coordinates is calculated for each observation time from the displacement amount for each observation target mark and each observation time, and the calculation result is stored. To do. Hereinafter, a method for calculating the displacement amount of the extraction point will be described.

FIG. 5 shows an example of a table that stores the calculated displacement amount. A table for storing the displacement amount of the extraction point is prepared for each observation time. For example, the extraction points are extracted so as to coincide with the lattice points of a square lattice provided at a certain lattice interval in the U-axis direction and the V-axis direction. The U coordinates of the extraction points are U ₁ , U ₂ , U ₃ ..., And the V coordinates are V ₁ , V ₂ , V ₃ . An area for storing the displacement (ΔU, ΔV) is secured for each extraction point.

With reference to FIG. 6, a method of calculating the displacement amount at the extraction point (U _i , V _j ) will be described. A plurality of observation object marks A _{1 to An} are distributed on the (U, V) plane. Displacement ΔU of each U-axis direction of the observation target marks A ₁ to A _n at the observation time t ₁ has already been determined as shown in FIG. The displacement amount at the extraction point (U _i , V _j ) can be estimated from the displacement amounts of a plurality of points whose displacement amounts are known, for example, by interpolation calculation. The displacement amount ΔV in the V-axis direction can be similarly estimated. Performs the same processing for each observation time of the observation time t ₂ later, for each observation time, the displacement of storage area of the table shown in FIG. 5, it stores the calculated displacement.

Instead of preparing the displacement amount storage table shown in FIG. 5, an approximate function of the displacement amount may be determined. The approximate functions fu and fv of the displacement amount can be expressed as follows, where the position on the image receiving surface is (U, V) and the elapsed time is t.
ΔU = fu (U, V, t)
ΔV = fv (U, V, t)
In step SA8, in consideration of lens characteristics, the (U, V) coordinates on the image receiving surface are set to polar angle θ with reference to the W axis of the first local coordinate system, and azimuth angle φ with reference to the UW surface. Convert to Further, the displacement amounts ΔU and ΔV are also converted into a polar angle variation Δθ and an azimuth variation Δφ. Hereinafter, the conversion method will be described.

  As shown in FIG. 7, when the lens is a thin single lens, if the distance L from the principal point 21 of the lens to the image receiving surface 22 is known, the (U, V) coordinates of the image AI of the observation target mark A are It can be converted into (θ, φ). Furthermore, the displacement amounts (ΔU, ΔV) can be converted into angle change amounts (Δθ, Δφ). Even when a compound lens is used, the displacement amounts (ΔU, ΔV) can be converted into angle variations (Δθ, Δφ) based on the lens characteristics.

  As shown in FIG. 8, for each observation time, an angle change amount table showing the relationship between the (θ, φ) coordinates corresponding to the extraction point and the angle change amounts (Δθ, Δφ) is prepared. In the angle change amount table, an area for storing the angle change amount is secured for each extraction point. The angle change amounts (Δθ, Δφ) calculated by the conversion are stored in the storage area for the angle change amount.

Instead of the angle change amount table shown in FIG. 8, an approximate function of the angle change amount may be determined. The approximate functions fθ and fφ of the angle change amount can be expressed as follows, where the polar angle is θ, the azimuth angle is φ, and the elapsed time is t.
Δθ = fθ (θ, φ, t)
Δφ = fφ (θ, φ, t)
In step SA9, based on the angle change amount table shown in FIG. 8, each angle change amount (Δθ, Δφ) of the node B on the surface observed by the first observation device 20 is calculated for each observation time. calculate.

  The global coordinates of node B are already stored in step SA3. Since the relationship between the global coordinate system and the first local coordinate system is already stored in step SA5, the local coordinates (θ, φ) of the node B can be obtained from the global coordinates of the node B. With reference to the angle change amount table shown in FIG. 8, the angle change amounts (Δθ, Δφ) can be calculated from the local coordinates (θ, φ) of the node B by interpolation or the like.

As shown in FIG. 9, a table for storing the time calendar of the angle change amounts (Δθ, Δφ) of the nodes B ₁ , B ₂ ... Is prepared. In this table, an area for storing the amount of change in angle (Δθ, Δφ) is secured for each node and each observation time. The calculated angle change amounts (Δθ, Δφ) are stored in the angle change amount storage area of the table shown in FIG.

  In step SA10, each angle change amount (Δθ, Δφ) of the node B on the surface observed by the first observation device 20 is converted into a displacement amount (ΔX, ΔY) in the global coordinate system.

Referring to FIG. 10, angle variation of the node B ₁ and ([Delta] [theta], [Delta] [phi), the displacement amount in the global coordinate system ([Delta] X, [Delta] Y) how to convert will be described. In the first observation device 20, it is assumed that since it was decided to measure the displacement in the direction perpendicular to the W axis of the first local coordinate system, the displacement direction of the node B ₁ represents, is perpendicular to the W-axis.

Define a virtual plane perpendicular Sw to W axis includes node B _1. In the first local coordinate system (theta, phi) intersection of the imaginary straight line and the virtual plane Sw extending in a direction matches to the node B ₁ at time t = t _i. The intersection of the virtual straight line extending in the (θ + Δθ, φ + Δφ) direction and the virtual plane Sw coincides with the node B ₁ at time t = ti _{+ 1} . In this way, the displacement (ΔX, ΔY) of the node B ₁ from time t _i to t _{i + 1} can be calculated.

  When the external force is uniform in the Z direction and the direction is parallel to the XY plane, the displacement amount of each node is considered to be substantially constant in the Z direction. Under this condition, the displacement amount of the nodes other than the nodes on the surface observed by the first observation device 20 can be calculated. Specifically, the displacement amount of the node of the point (X, Y, Z) is the same as the (X, Y) coordinate of the node and is observed by the first observation device 20. It is presumed that the amount of displacement of the node located on the surface is the same.

As shown in FIG. 11, a displacement time calendar table for storing the displacements (ΔX, ΔY) of the nodes B ₁ , B ₂ ... Is prepared. In this table, an area for storing displacement (ΔX, ΔY) is secured for each node and each observation time. The calculated displacement amount is stored in the corresponding storage area of the displacement amount time calendar table.

  Based on the image data obtained by the second observation device 30, the displacement (ΔY, ΔZ) at each observation time of each node on the surface observed by the second observation device 30 is obtained in the same manner. If the displacement ΔY of each node calculated based on the image data obtained by the second observation device 30 is substantially constant in the Z direction, the calculation is performed based on the image data obtained by the first observation device 20. It is confirmed that the prediction that the displacement (ΔX, ΔY) made is substantially constant in the Z direction was valid.

  In step SA11, the state of change in the shape of the measuring object 10 is displayed as a moving image on the image display device 41 based on the nodal displacement amount time calendar table shown in FIG.

  FIG. 12 shows a schematic diagram of the image display device 41. An object display area 42 is secured in the display screen, and an operation unit 43, an elapsed time display bar 44, and a display command unit 45 are displayed outside thereof. In the object display area 42, the object is displayed three-dimensionally. Through the operation unit 43, operations such as display start, display stop, and display pause are performed. In the elapsed time display bar 44, the elapsed time up to the currently displayed time is displayed in a bar shape. Moreover, the elapsed time from the observation start can be designated via the elapsed time display bar, and the change in shape from the designated time can be displayed.

  An instruction to enlarge, reduce, rotate, etc. the image displayed in the object display area 42 is given through the display command unit 45. For this reason, the deformation of the observation object 10 can be confirmed from various viewpoints. The displacement amount of each node can be enlarged and displayed. When the change in the shape of the observation object is slight, it is easy to visually recognize the change in the shape by displaying the displacement amount in an enlarged manner.

  By continuously displaying the shape of the measurement object as time passes, the change in the shape of the measurement object 10 can be easily grasped visually. In order to make it easy to grasp the deformation amount of each part, an equal displacement amount line may be displayed, or a contour display in which the display color is changed according to the displacement amount may be performed.

  In the above-described embodiment, it is assumed that the observation object 10 is displaced mainly only in the direction parallel to the XY plane. Next, a case where a displacement in the Z direction is detected by the second observation apparatus 30 will be described.

As shown in FIG. 13, the observation target mark Ai on the observation target 10 is observed by the first observation device 20, and the observation target mark Aj is observed by the second observation device 30. According to the analysis of the image data acquired by the first observation device 20, the observation target mark Ai is changed from Ai (t = t _i ) to Ai (t = t) in the direction perpendicular to the W axis, that is, the direction parallel to the XY plane. It is presumed that it has been displaced to t _{i + 1} ). Similarly, from the analysis of the image data acquired by the second observation apparatus 30, the observation target mark Aj is changed from Aj (t = t _i ) to Aj in the direction perpendicular to the T axis, that is, in the direction parallel to the YZ plane. It is presumed that the displacement has occurred at (t = t _{i + 1} ).

The displacement of the node Bk near the observation target marks Ai and Aj is affected by the displacement of the observation target marks Ai and Aj. Considering only the displacement of the observation target mark Ai, the displacement destination of the node Bk is predicted as the point Bki displaced in the direction parallel to the XY plane. Considering only the displacement of the observation target mark Aj, the displacement destination of the node Bk is predicted to be the point Bkj displaced in the direction parallel to the YZ plane. The actual displacement is a combination of the displacement to the displacement destination Bki and the displacement to the displacement destination Bkj. The actual displacement destination Bk (t = t _{i + 1} ) can be obtained by weighting and combining the displacement to the displacement destination Bki and the displacement to the displacement destination Bkj. The weighting is performed in consideration of the distance from the node Bk to the observation target marks Ai and Aj.

  In general stereo measurement, one observation target mark must be observed simultaneously by two cameras. In the method according to the above-described embodiment, even when different observation target marks Ai and Aj are observed with the two observation devices 20 and 30, the displacement of the node Bk in the three-dimensional direction can be estimated. Note that the number of observation devices is not limited to one or two. Three or more observation devices may be used.

  Next, a displacement calculation method when observing one observation target mark with the two observation devices 20 and 30 will be described.

As shown in FIG. 14, one observation target mark Ai is observed by both the first observation device 20 and the second observation device 30. By analyzing the image data acquired by the first observation device 20, the displacement destination Ai1 (t = t _{i + 1} ) in the direction perpendicular to the W axis is determined. By analyzing the image data acquired by the second observation device 30, a displacement destination Ai2 (t = t _{i + 1} ) in a direction perpendicular to the T axis is determined. The actual displacement destination Ai (t = t _{i + 1} ) is a straight line SL ₁ connecting the origin of the first local coordinate system and the displacement destination Ai1 (t = t _{i + 1} ), and the origin and displacement destination of the second local coordinate system. It matches the intersection of the straight line SL ₂ connecting the _{Ai2 (t = t i + 1} ). In this way, the actual displacement destination Ai (t = t _{i + 1} ) can be calculated.

  In the above embodiment, in step SA8, the position and displacement of the extraction point are represented by the polar angle θ and the azimuth angle φ in the local coordinate system. The polar angle θ and the azimuth angle φ are not affected by the magnification depending on the distance between the observation apparatus and the observation target mark. Since it is not necessary to perform calculation in consideration of the difference in magnification, it is possible to reduce the calculation time for calculating the displacement.

  Next, with reference to FIG. 15, another configuration example for fixing the measurement target mark to the observation target object 10 will be described.

  As shown in FIG. 15, for example, one surface 14 of the observation object 10 faces the first observation object 20. A plurality of mark display members 11 are attached to a surface 15 that faces in the lateral direction when viewed from the first observation device 20. Each of the mark display members 15 protrudes from the surface 15 and includes a surface facing the first observation device 20. An observation target mark C is displayed on the surface facing the first observation apparatus 20.

  When the surface 15 is parallel to the W axis, the mark drawn directly on the surface 15 cannot be observed by the first observation device 20. As shown in FIG. 15, by attaching the mark display member 11 protruding from the surface 15, the observation target mark C fixed to the surface 15 can be observed by the first observation device 20.

  The second observation apparatus 30 shown in FIG. 1 cannot detect the displacement in the X-axis direction of the observation target mark fixed to the surface 15 in FIG. By observing the observation target mark C fixed to the surface 15 using the mark display member 11 with the first observation device 20, the displacement of the observation target mark C in the X-axis direction can be detected.

  It is preferable to arrange the mark display members 11 so as not to overlap each other with respect to the direction (V-axis direction in FIG. 15) perpendicular to the W axis and included in the surface 15. With this arrangement, all the observation target marks C fixed on the surface 15 can be observed with the first observation device 20.

  Of the observation target marks C arranged at different positions in the W-axis direction, those located within the depth of field of the first observation device 20 can be imaged on the image receiving surface. Even when the image is not formed on the image receiving surface outside the depth of field, the (U, V) coordinates of the image of the observation target mark C can be detected by using a technique such as centroid calculation.

  FIG. 16 shows a front view of an injection molding machine in which the shape change measuring device according to the above embodiment can be mounted. The injection molding machine 340 includes an injection device 350 and a mold clamping device 370.

  The injection device 350 includes a heating cylinder 351, and a hopper 352 that supplies resin is disposed in the heating cylinder 351. Further, a screw 353 is disposed in the heating cylinder 351 so as to be able to advance and retreat and to be rotatable. The rear end of the screw 353 is rotatably supported by the support member 354. A measuring motor 355 such as a servo motor is attached to the support member 354 as a drive unit. The rotation of the weighing motor 355 is transmitted to the screw 353 of the driven portion via a timing belt 356 attached to the output shaft 361 of the weighing motor 355. A detector 362 is directly connected to the rear end of the output shaft 361 of the weighing motor 355. The detector 362 detects the rotation speed or rotation amount of the metering motor 355. Based on the number of rotations or amount of rotation detected by the detector 362, the rotational speed of the screw 353 is obtained.

  The injection device 350 further includes a screw shaft 357 parallel to the screw 353 so as to be rotatable. The rear end of the screw shaft 357 is connected to the injection motor 359 via a timing belt 358 attached to the output shaft 363 of the injection motor 359 such as a servo motor. Therefore, the screw shaft 357 can be rotated by the injection motor 359. The front end of the screw shaft 357 is screwed with a nut 360 fixed to the support member 354. When the injection motor 359 that is a drive unit is driven and the screw shaft 357 that is a drive transmission unit is rotated via the timing belt 358, the support member 354 moves forward and backward.

  A load cell 365 as a load detector is attached to the support member 354. The forward / backward movement of the support member 354 is transmitted to the screw 353 via the load cell 365, whereby the screw 353 moves forward / backward. Data corresponding to the force detected by the load cell 365 is sent to the control device 310. A detector 364 is directly connected to the rear end of the output shaft 363 of the injection motor 359. The detector 364 detects the rotation speed or rotation amount of the injection motor 359. Based on the number of rotations and the amount of rotation detected by the detector 364, the moving speed of the screw 353 in the forward / backward direction or the position in the forward / backward direction is obtained.

  The mold clamping device 370 includes a movable platen 372 to which a movable mold 371 is attached, and a fixed platen 374 to which a fixed mold 373 is attached. The movable platen 372 and the fixed platen 374 are connected by a tie bar 375. The movable platen 372 is slidable along the tie bar 375. The mold clamping device 370 includes a toggle mechanism 377. The toggle mechanism 377 has one end connected to the movable platen 372 and the other end connected to the toggle support 376. A ball screw shaft 379 is rotatably supported at the center of the toggle support 376. A nut 381 fixed to a cross head 380 provided in the toggle mechanism 377 is screwed onto the ball screw shaft 379. A pulley 382 is disposed at the rear end of the ball screw shaft 379, and a timing belt 384 is stretched between the output shaft 383 of the mold clamping motor 378 such as a servo motor and the pulley 382.

  In the mold clamping device 370, when the mold clamping motor 378 that is a drive unit is driven, the rotation of the mold clamping motor 378 is transmitted to the ball screw shaft 379 that is the drive transmission unit via the timing belt 384. Then, the ball screw shaft 379 and the nut 381 change the direction of motion from rotational motion to linear motion, and the toggle mechanism 377 is operated. By the operation of the toggle mechanism 377, the movable platen 372 slides along the tie bar 375, and mold closing, mold clamping, and mold opening are performed.

  A detector 385 is directly connected to the rear end of the output shaft 383 of the mold clamping motor 378. The detector 385 detects the rotation speed or rotation amount of the mold clamping motor 378. Based on the number of rotations or the amount of rotation detected by the detector 385, the position of the crosshead 380 that moves forward and backward with the rotation of the ball screw shaft 379, or the driven part connected to the crosshead 380 by the toggle mechanism 377 The position of a certain movable platen 372 is determined. The control device 310 controls the measuring motor 355, the injection motor 359, and the mold clamping motor 378.

  A cavity cav is formed between the movable mold 371 and the fixed mold 373. The cavity cav and the inside of the heating cylinder 351 communicate with each other.

  When the mold clamping is performed, stress is applied to the movable mold 371 and the fixed mold 373, and these molds are slightly deformed. In order to increase the precision of the shape of the injection molded product, it is desired to observe a slight deformation of the mold.

  A plurality of observation target marks are fixed to the side surfaces of the movable mold 371 and the fixed mold 373. By observing these observation target marks using the shape change device according to the above embodiment, the state of deformation of the mold can be confirmed by an image.

  In the above-described embodiment, the digital camera is used for the observation device 20 and 30 for detecting the displacement amount of the observation target mark A. However, the displacement amount may be detected by other methods. For example, it is also possible to detect the displacement amount of the observation target mark using a laser displacement meter.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

It is the schematic of the shape change measuring apparatus by an Example. It is a flowchart which shows the shape change measuring method by an Example. It is a diagram which shows the state which divided | segmented the measurement object into the some finite element virtually. It is a diagram which shows the table which memorize | stores the coordinate of an observation object mark, and the time calendar of displacement amount. It is a diagram which shows the table which memorize | stores the displacement amount ((DELTA) U, (DELTA) V) of an extraction point (U, V). It is a graph for demonstrating the calculation method of the displacement amount of an extraction point from the displacement amount of an observation object mark. It is a diagram for explaining a method of converting (U, V) coordinates on an image receiving surface into (θ, φ) coordinates. It is a diagram which shows the table which memorize | stores the angle variation | change_quantity ((DELTA) (theta), (DELTA) (phi)) of extraction point ((theta), (phi)). It is a diagram which shows the table which memorize | stores the time calendar of the angle variation | change_quantity ((DELTA) (theta), (DELTA) phi) of a node. FIG. 5 is a diagram for explaining a method of converting an angle change amount (Δθ, Δφ) into a displacement amount (ΔX, ΔY) in the global coordinate system. It is a diagram which shows the table which memorize | stores the time calendar of the displacement amount ((DELTA) X, (DELTA) Y) of a node. It is the schematic of the image display apparatus used for the shape change measuring apparatus by an Example. A method for calculating a displacement amount of a node based on a displacement of an observation target mark observed by the first observation device and a displacement of another observation target mark observed by the second observation device. FIG. It is a diagram for explaining a method of calculating a displacement amount of an observation target mark when one observation target mark is observed by the first and second observation apparatuses. It is a perspective view which shows the other example of the fixing method of an observation object mark. It is a front view of the injection molding machine which can mount | wear with the shape change measuring apparatus by an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Observation object 11 Mark display member 20 1st observation apparatus 30 2nd observation apparatus 40 Processing apparatus 41 Image display apparatus 42 Object display area 43 Operation part 44 Elapsed time display bar 45 Display command part A, C Observation object mark B Node XYZ Global coordinate system UVW First local coordinate system RST Second local coordinate system

Claims (5)

A first observation device that observes the measurement target mark and obtains position information of the measurement target mark;
An image output device for outputting an image;
A control device for controlling the first observation device and the image output device;
The control device includes:
The analysis model corresponding to the measurement object is divided into a plurality of finite elements, and the positions of the nodes of the finite elements are stored.
Storing the positions of a plurality of measurement object marks defined on the measurement object;
Obtaining a time calendar of each position information of the measurement target mark from the first observation device;
Based on the time calendar of the position information acquired from the first observation device, to calculate the displacement of each of the nodes,
A shape change measurement device that displays a change in the shape or posture of the measurement object on the image output device based on the displacement of each of the nodes. The first observation device includes a lens and an image receiving surface, and outputs image data of an image projected on the image receiving surface via the lens to the control device,
The control device includes:
Based on the time calendar of the image data acquired from the first observation device, obtain the time calendar of the position of the measurement target mark in the image receiving surface,
From the time calendar of the position of the measurement target mark in the image receiving surface, calculate the time calendar of the displacement of the measurement target mark,
The shape change measurement apparatus according to claim 1, wherein a time calendar of displacement of the node is calculated based on a time calendar of displacement of the measurement target mark. A first local coordinate system by a W axis that coincides with the optical axis of the lens of the first observation apparatus, a U axis and a V axis that pass through the principal point of the lens and are orthogonal to the W axis and orthogonal to each other When defining
The control device includes:
The displacement of the image on the image receiving surface is converted into a change amount of the polar angle with respect to the W axis and a change amount of the azimuth angle with respect to the UW plane,
The displacement of each of the nodes is represented by a change amount of the polar angle with respect to the W axis and a change amount of the azimuth angle with respect to the UV plane,
The shape change according to claim 2, wherein the displacement of the node is calculated based on a change amount of the polar angle with respect to the W axis and a change amount of the azimuth angle with respect to the UV plane of each of the nodes. measuring device. And a second observation device that observes the measurement target mark and obtains position information of the measurement target mark,
The second observation device includes a lens and an image receiving surface, and outputs image data of an image projected on the image receiving surface via the lens to the control device,
A second local coordinate system by a T-axis coinciding with the optical axis of the lens of the second observation device, an R-axis and an S-axis passing through the principal point of the lens and orthogonal to the T-axis and mutually orthogonal When defining
The control device includes:
When calculating the displacement of each of the nodes, not only the change amount of the polar angle based on the W axis and the change amount of the azimuth angle based on the UV plane, but also the change amount of the polar angle based on the T axis. The shape change measuring device according to claim 3, wherein the displacement of each of the nodes is calculated based on a change amount of the azimuth angle with respect to the RT plane. Dividing the analysis model corresponding to the measurement object into a plurality of finite elements, and determining the positions of the nodes between the finite elements;
Measuring a time calendar of the position of a plurality of measurement object marks fixed to the measurement object;
Calculating a time calendar of displacement of each of the nodes based on a time calendar of the position of the measurement target mark;
And a step of displaying a change in shape of the measurement object as an image based on a time calendar of displacement of each of the nodes.

Images