CN113560942B

CN113560942B - Workpiece pick-and-place control device of machine tool and control method thereof

Info

Publication number: CN113560942B
Application number: CN202110878213.4A
Authority: CN
Inventors: 林家暐; 庄易勋; 胡育豪
Original assignee: Syntec Technology Suzhou Co Ltd
Current assignee: Syntec Technology Suzhou Co Ltd
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2022-11-08
Anticipated expiration: 2041-07-30
Also published as: CN113560942A

Abstract

The invention discloses a workpiece taking and placing control device of a machine tool and a control method thereof. The workpiece pick-and-place control device comprises a first sensor, a second sensor and a controller. The first sensor generates a first sensing signal according to the collided state. The second sensor captures images of the workpiece and the clamping part. The controller is used for executing the following operations: driving the clamping part to move to the detection area according to the first sensing signal; enabling a second sensor to capture first and second images of the workpiece and the clamping part under different postures; comparing the first and second images with first and second feature data to generate corresponding error values, wherein the first and second feature data respectively describe the image profiles of the working and clamping parts; and adjusting at least one of the positions of the clamping part and the workpiece according to the error value.

Description

Workpiece pick-and-place control device of machine tool and control method thereof

Technical Field

The present invention relates to a control device and a control method, and more particularly, to a workpiece picking and placing control device of a machine tool and a control method thereof.

Background

Robotic arms are widely used in automated systems and are gradually replacing manual tasks. In various applications, the robot is configured to perform corresponding operations automatically, wherein the operations include: for example, a workpiece of the target is moved to a specific position or the like. When an object is taken or put back, if the robot arm or the workpiece collides, the operation in progress is disturbed. Therefore, the robot arm needs to improve the operation process for the collision situation.

Disclosure of Invention

The invention provides a workpiece taking and placing control device of a machine tool, which can automatically process the condition that a mechanical arm collides.

The workpiece pick-and-place control device of the machine tool comprises a first sensor, a second sensor and a controller. The first sensor is arranged on a clamping part of the pick-and-place device, and the clamping part is used for clamping a workpiece to a machine tool. The first sensor generates a first sensing signal according to the impacted state of the clamping part and the workpiece. The second sensor is used for capturing images of the workpiece and the clamping part. The controller is coupled with the first sensor, the second sensor and the clamping part. The controller is used for executing the following operations: driving the clamping part to move to the detection area according to the first sensing signal; enabling a second sensor to capture a first image and a second image of the workpiece and the clamping part in different postures in the detection area; comparing the first image and the second image with the first characteristic data and the second characteristic data respectively to generate a first error value corresponding to the workpiece and a second error value corresponding to the clamping part, wherein the first characteristic data and the second characteristic data respectively describe the image outlines of the workpiece and the clamping part; and adjusting at least one of the position of the clamping part and the position of the workpiece according to the first error value and the second error value.

The invention also provides a workpiece taking and placing control method of the machine tool, which can automatically process the collision condition of the mechanical arm.

The workpiece picking and placing control method of the machine tool comprises the following operations: arranging a first sensor on a clamping part of the taking and placing device, and enabling the first sensor to generate a first sensing signal according to the collision state of the clamping part and the workpiece; driving the clamping part to move to the detection area according to the first sensing signal; enabling a second sensor to capture a first image and a second image of the workpiece and the clamping part in different postures in the detection area; comparing the first image and the second image with the first characteristic data and the second characteristic data respectively to generate a first error value corresponding to the workpiece and a second error value corresponding to the clamping part, wherein the first characteristic data and the second characteristic data respectively describe the image outlines of the workpiece and the clamping part; and adjusting at least one of the position of the clamping part and the position of the workpiece according to the first error value and the second error value.

Based on the above, the embodiment of the invention utilizes the plurality of images captured by the second sensor to obtain the current postures of the clamping portion and the workpiece. The images are further compared with corresponding characteristic data so as to adjust the position of the clamping part and/or the workpiece according to the comparison result. Therefore, the workpiece taking and placing control device and the control method thereof of the machine tool can automatically adjust the state of the clamping part and/or the workpiece when the clamping part or the workpiece collides, and the self-solution flow can improve the working efficiency of the machine tool operation.

Drawings

Fig. 1 is a block diagram illustrating a workpiece pick-and-place control apparatus of a machine tool according to an embodiment of the present invention.

Fig. 2 is a schematic diagram illustrating a workpiece pick-and-place control device of a machine tool according to an embodiment of the invention.

Fig. 3A-3F are schematic diagrams of images captured by the sensor of fig. 2 according to some embodiments of the invention.

Fig. 4 is a flowchart illustrating a workpiece picking and placing control method of a machine tool according to an embodiment of the invention.

Fig. 5A to 5B are flowcharts illustrating a workpiece picking and placing control method of a machine tool according to an embodiment of the invention.

Description of the symbols:

100: workpiece taking and placing control device

110: first sensor

120: second sensor

130: controller

400: workpiece picking and placing control method

500: workpiece picking and placing control method

ARM: taking and placing device

AX1, AX2: center shaft

CL: clamping part

D1: distance between two adjacent plates

L1: virtual shaft

P0, P0', P1: origin point

S410 to S450: step (ii) of

S511 to S541: step (ii) of

TH1, TH2: angle of rotation

WP: workpiece

X, X ', Y', Z: shaft

Detailed Description

Referring to fig. 1, fig. 1 is a block diagram illustrating a workpiece pick-and-place control device 100 of a machine tool according to an embodiment of the invention. In fig. 1, the workpiece pick-and-place control device 100 includes a pick-and-place device ARM, a first sensor 110, a second sensor 120, and a controller 130. Wherein the pick-and-place device ARM comprises a clamping part CL. The first sensor 110 is disposed on the clamping portion CL of the pick-and-place device ARM, and is configured to sense the clamping portion CL and a collision state of the workpiece clamped by the clamping portion CL to generate a first sensing signal. The first sensor 110 is coupled to the controller 130 for transmitting the generated first sensing signal to the controller 130. The second sensor 120 is coupled to the controller 130, and is configured to capture a plurality of images of the workpiece and the clamping portion CL, and transmit the generated first image and second image to the controller 130. The controller 130 is further coupled to the pick-and-place device ARM and the clamping portion CL, and is configured to receive a collision signal from the pick-and-place device ARM when the pick-and-place device ARM detects a collision.

In the embodiment, the pick-and-place device ARM is used for carrying the clamping part CL. A sensor (not shown) may be disposed on the pick-and-place device ARM for detecting the collided state of the pick-and-place device ARM. When the controller 130 determines that the pick-and-place device ARM is collided, it may send a warning signal and stop the workpiece pick-and-place operation of the pick-and-place device ARM. The pick-and-place device ARM can be a mechanical ARM. In another embodiment of the present invention, the pick-and-place device ARM does not need to be provided with an external sensor, and the controller 130 can determine the collided state of the pick-and-place device ARM by a current or torque signal (i.e. a collision signal) generated by a motor coupled to the pick-and-place device ARM. For example, when the pick-and-place device ARM is collided during operation, the pick-and-place device ARM cannot travel to the originally predetermined position. The controller 130 detects the increase of the motor current value coupled to the pick-and-place device ARM, and when the increase of the motor current value is within the allowable range, the controller 130 adjusts the current supplied to the motor as required to make the pick-and-place device ARM continue to operate. On the other hand, when the motor current value increases beyond the allowable range, the controller 130 sends out a warning signal and stops the machine for the waiting personnel to check.

The clamp unit CL clamps a workpiece to a machine tool (not shown). In an embodiment of the invention, the clamping portion CL may be disposed at an end of the pick-and-place device ARM. The clamping section CL may be implemented as an application terminal aligner.

The first sensor 110 is used for generating a first sensing signal to the controller 130 according to the collision status of the clamping part CL and the workpiece clamped thereby, so that the controller 130 can know the collision status of the clamping part CL and the workpiece clamped thereby. The first sensor 110 may be implemented as a force sensor as well as a resistive or capacitive pressure sensor. The first sensing signal may be at least one of a force value and a pressure value of the clamping portion CL. The second sensor 120 is used for capturing images of the clamping part CL and the workpiece clamped by the clamping part CL, and transmitting the generated images to the controller 130.

From the images, the controller 130 can obtain the relative position of the clamping part CL and the workpiece in real time. In embodiments of the present invention, the second sensor 120 may be disposed at any location in the detection area. Accordingly, the second sensor 120 may generate a plurality of images (e.g., a first image and a second image) by capturing the clamping portion CL and the workpiece at different angles when the clamping portion CL and the workpiece are moved into the detection area. In some embodiments, the second sensor 120 is implemented as a camera or video camera. In some embodiments, the images generated by the second sensor 120 may be still pictures or moving images (e.g., movies). In an embodiment of the present invention, the detection area is disposed around the workpiece pick-and-place control apparatus 100, for example, the detection area is disposed outside the machine tool. In another embodiment of the invention, the inspection area is provided inside the machine tool, for example above the workpiece.

The controller 130 is configured to receive a first sensing signal from the first sensor 110. When the first sensing signal indicates that at least one of the clamping portion CL and the workpiece collides, the controller 130 drives the clamping portion CL to move to the detection area (not shown) according to the first sensing signal. The detection area may be an area provided in the gripping section CL to grip the workpiece. In the embodiment of the invention, when the controller 130 determines that at least one of the clamping portion CL and the workpiece collides with each other according to the first sensing signal, it can send out an alarm signal and stop the workpiece pick-and-place operation of the pick-and-place device ARM. Further, the controller 130 drives the clamping portion CL to move to the detection area according to the first sensing signal.

In the inspection area, the controller 130 is further configured to enable the second sensor 120 to capture a first image and a second image of the workpiece and the clamping part CL in different postures in the inspection area. The controller 130 receives the first image and the second image from the second sensor 120, compares the first image with the first characteristic data to generate a first error value corresponding to the workpiece, and compares the second image with the second characteristic data to generate a second error value corresponding to the clamping portion CL. The first characteristic data and the second characteristic data respectively describe the image contour of the workpiece and the clamping part CL under the normal condition that the workpiece and the clamping part CL are not collided.

The controller 130 is further configured to drive at least one of the clamping portion CL and the pick-and-place device ARM to move according to the first error value and the second error value, so as to adjust at least one of the position of the clamping portion CL and the position of the workpiece.

In addition, when the detection region is disposed outside the machine tool, the controller 130 may adjust at least one of the position of the clamping portion CL and the position of the workpiece according to the first error value and the second error value. And the position of the clamping part CL and the position of the workpiece can continue to execute subsequent machining actions, and then the clamping part CL and the workpiece are moved to the machine tool for subsequent machining actions. In another embodiment of the present invention, the detection region is disposed outside the machine tool, and the controller 130 can adjust at least one of the position of the clamping portion CL and the position of the workpiece according to the first error value and the second error value, and then follow the subsequent processing operation.

On the other hand, when the first error value is greater than the first allowable range, which indicates that the workpiece on the clamping portion CL is excessively severely skewed due to collision, the controller 130 may cause the clamping portion CL to discard the workpiece. Then, the controller 130 may cause the clamping portion CL to re-clamp the workpiece to continue the machining operation, or the controller 130 may send an alarm signal to notify field personnel to perform troubleshooting. In the present invention, the case where the controller 130 causes the clamping portion CL to re-clamp the workpiece includes two embodiments, the first is that the clamping portion CL releases the existing workpiece, and re-clamps the workpiece after adjusting the position; the second is that the clamp part CL releases the existing workpiece and adjusts the position to clamp another workpiece.

When the second error value is greater than the second allowable range, it indicates that the clamping portion CL is too severely skewed due to collision, and the controller 130 can send an alarm signal to notify field personnel to perform troubleshooting. The warning signal may be a sound, a light, or any form of warning signal, without limitation. In another embodiment of the present invention, the controller 130 may send an alert signal to a remote server or a cloud control interface, etc. to notify personnel to perform troubleshooting.

When the first error value and the second error value are both greater than the reference value, it indicates that the pick-and-place device ARM may be skewed due to a mechanical problem. The controller 130 can send an alarm signal to notify personnel to perform troubleshooting and stop the workpiece pick-and-place operation of the pick-and-place device ARM.

In some embodiments, the workpiece pick-and-place control apparatus 100 further comprises at least one memory device (not shown). The memory device is coupled to the controller 130 and is used for storing data required by the operation of the workpiece pick-and-place control apparatus 100, wherein the data includes: for example, the first image and the second image, the coordinate system and the first feature data and the second feature data. The first characteristic data and the second characteristic data correspond to the images of the workpiece WP and the clamping part CL, respectively, and are used for comparing with the first image and the second image respectively. The memory element may be implemented using a memory or a database. The memory device may also be a remote server or a cloud hard disk coupled to the controller 130.

Referring to fig. 2, fig. 2 is a schematic view illustrating a workpiece pick-and-place control device 100 of a machine tool according to an embodiment of the invention. In some embodiments, the control device 100 shown in fig. 2 is an embodiment for implementing the block diagram shown in fig. 1, and illustrates a state that the workpiece picking and placing control device 100 of the machine tool picks up the workpiece WP. Therefore, in fig. 2, referring to fig. 1, the same elements are denoted by the same reference numerals and are not described herein again.

In fig. 2, compared to the embodiment of fig. 1, the clamping portion CL is at least two clamping jaw portions for clamping the workpiece WP. A simulated coordinate system is generated in the space by taking any point of the clamping part CL or the pick-and-place device ARM as an original point P0. In some embodiments, as shown in fig. 2, a point at the end of the pick-and-place device ARM is taken as an origin P0 with respect to the central axis of the clamping part CL, and a rectangular coordinate system is generated, which is respectively represented by an X-axis, a Y-axis and a Z-axis. In some embodiments, the coordinate system of the clamping portion CL further includes a rotation axis, e.g., C6 axis.

The second sensor 120 is used to photograph the clamping portion CL and the work WP in different postures or orientations under the same condition. In this embodiment, the second sensor 120 is allowed to move in space. In other embodiments, the workpiece pick-and-place control apparatus 100 includes a plurality of second sensors 120, and the second sensors 120 are respectively disposed at different positions in the working environment of the machine tool.

Referring to fig. 2 and fig. 3A to 3F simultaneously, fig. 3A to 3F are schematic diagrams illustrating an adjusting operation of the clamping portion and the workpiece according to an embodiment of the present invention. In fig. 3A, based on a coordinate system, the origin P0 of the coordinate system, the central axis of the clamping portion CL and the central axis of the work WP may all be located on the X-axis, and the end of the work WP is located on a virtual axis L1 parallel to the Y-axis. The origin P0 of the coordinate system of the present embodiment may be set at any reference position of the clamp part CL. Fig. 3A shows an image of the workpiece WP when the workpiece placing and placing control device 100 is normally used and no collision occurs. I.e., first feature data and second feature data corresponding to the image profiles of the work WP and the clamping portion CL, respectively. In some embodiments, FIG. 3A shows an initial image.

In fig. 3B, the origin P0 is shifted to a new origin P1 and shifted from the origin P0 by a distance D1 in the Y-axis direction compared to fig. 3A. The center axis AX1 of the clamp part CL is offset from the X axis by an angle TH 1. In addition, the central axis AX2 of the workpiece WP is offset from the central axis AX1 by an angle TH2, and the end of the workpiece WP is not parallel to the virtual axis L1. Fig. 3B shows that at least one of the clamping portion CL and the workpiece WP collides. In some embodiments, the first image is shown in FIG. 3B. In other words, the clamping portion CL has an angular difference (i.e., the angle TH 1) in the first image, and the work piece WP has another angular difference (i.e., the angle TH 2) in the first image.

Continuing with the above description, in this configuration, controller 130 can compare fig. 3A and 3B and generate the difference between the image profiles of each element in the X-Y plane. The above-mentioned differences include: such as distance D1, angle TH1, and angle TH2.

In this case, in addition to the images in the X-Y plane shown in FIGS. 3A and 3B, the second sensor 120 can generate a second image at another viewing angle (e.g., Y-Z plane). Similar to the description of fig. 3A and 3B, the controller 130 can generate the difference between the image profiles of the components of the clamping portion CL and the workpiece WP in the Y-Z plane. The clamping portion CL, the workpiece WP and the second sensor 120 are all located in the detection area, and the second sensor 120 captures an image of the clamping portion CL and the workpiece WP on the X-Y plane (i.e. the first posture) to generate a first image. Then, the clamp part CL moves to make the clamp part CL and the workpiece WP generate a second image on the Y-Z plane (i.e., the second posture). In this embodiment, the second sensor 120 can capture images of the clamping portion CL and the workpiece WP on different planes at a fixed position.

In another embodiment, the clamping portion CL, the workpiece WP and the second sensor 120 are all located in the detection area, and the second sensor 120 captures an image of the clamping portion CL and the workpiece WP on the X-Y plane (i.e. the first posture) to generate a first image; the second sensor 120 captures an image of the clamping portion CL and the workpiece WP in the Y-Z plane (i.e., the second orientation) to generate a second image. The second sensor 120 is moved on the X-Y plane and the Y-Z plane to capture images of the clamping portion CL and the workpiece WP. On the other hand, the second sensors 120 may be provided on the X-Y plane and the Y-Z plane, respectively, to capture images of the clamping portion CL and the workpiece WP.

In fig. 3C, the controller 130 performs a position adjustment operation of the clamping portion CL and the work WP. The controller 130 can drive the CL portion to move along the Y axis and zero the distance D1. Moreover, the controller 130 can drive the clamp CL to rotate so that the axis of the workpiece WP can be aligned with the X axis. As such, the offset angle TH2 may be zeroed.

In fig. 3D, compared to fig. 3C, the controller 130 drives the clamping portion CL to move the end of the workpiece WP onto the virtual axis L1, so as to eliminate the offset between the end of the workpiece WP and the virtual axis L1. Accordingly, the work piece WP can be adjusted to an appropriate position.

Next, in fig. 3E, the outlines of the work WP in fig. 3D and 3A are superimposed on each other, and the relative positions of the clamping portion CL and the work WP in the space are adjusted by coordinate correction.

In fig. 3E and 3F, the adjusted clamping portion CL has a new coordinate system. This coordinate system is represented by the X ', Y' and Z 'axes (not shown), respectively, and has a new origin P0'. Therefore, the adjusted clamping portion CL can take and place the workpiece WP continuously in the updated coordinate system.

Referring to fig. 4, fig. 4 is a flowchart illustrating a workpiece picking and placing control method 400 of a machine tool according to an embodiment of the invention. In some embodiments, the method 400 of fig. 4 is implemented in the operation of the work pick and place control device 100 of fig. 1 and 2 to self-eliminate the collision of the work pick and place control device 100 or the work WP. The method 400 includes steps S410 to S450.

In step S410, the first sensor generates a first sensing signal according to the impacted state of the clamping portion and the workpiece. In step S420, the clamping portion moves to the detection area according to the first sensing signal. In step S430, the second sensor captures a first image and a second image of the workpiece and the clamping portion in different postures in the detection area. In step S440, the first image is compared with the first characteristic data to generate a first error value corresponding to the workpiece, and the second image is compared with the second characteristic data to generate a second error value corresponding to the clamping portion. In step S450, at least one of the position of the clamping portion and the position of the workpiece is adjusted according to the first error value and the second error value. Therefore, the collision situation is automatically eliminated, and the operation of taking and placing the workpiece can be continued.

The details of the above steps have been described in detail in the foregoing embodiments, and are not repeated herein.

Referring to fig. 5A to 5B, fig. 5A to 5B are flowcharts illustrating a workpiece picking and placing control method 500 of a machine tool according to an embodiment of the invention. In some embodiments, the method 500 of fig. 5A-5B is implemented to implement the operation of the workpiece pick-and-place control apparatus 100 of fig. 1 and 2. The method 500 is used to self-resolve the impacted condition during a machine tool pick-and-place operation. In some embodiments, method 500 is an alternative embodiment of method 400. From the beginning to the end, the method 500 includes steps S511 to S541.

In fig. 5A, steps S511 to S521 are the flow of the process after the occurrence of a possible collision, and the flow of fig. 5B is continued by the node N1.

In step S511, the controller determines whether the pick-and-place device detects a collision according to the collision signal detected by the pick-and-place device. When the pick-and-place device does not detect a collision, it indicates that no collision has occurred, and the method 500 ends. Otherwise, step S513 is executed. In step S513, the controller determines whether the first sensor detects a collision according to the first sensing signal detected by the first sensor. When the first sensor does not detect the collision, it indicates that the pick-and-place device collides, the posture of the pick-and-place device needs to be checked first, and then step S515 is executed. Otherwise, step S517 is executed. In step S515, according to the first sensing signal, the controller sends an alarm signal to the machine tool, so that the machine tool emits an alarm sound or an alarm light signal, and drives the pick-and-place device to stop picking and placing the device. The method 500 then ends.

In addition, in step S517, the controller drives the pick-and-place device to move to the detection area. In step S519, the controller determines whether the pick-and-place device is located in the detection area according to the signal detected by the pick-and-place device. When the pick-and-place device is not located in the detection area, it indicates that the pick-and-place device may collide for the second time during the moving process, and step S521 is performed. Otherwise, the process continues to node N1.

In step S521, the controller determines whether the pick-and-place device detects a collision according to the collision signal detected by the pick-and-place device. When the pick-and-place device does not detect the collision, it indicates that the second collision does not occur, and step S517 is repeated. Otherwise, it indicates that the collision repeatedly occurs, so that the overall posture of the pick-and-place apparatus is changed too much to eliminate the collision, and step S515 is performed to end the method 500.

In fig. 5B, steps S523 to S541 are flows of correcting the collision offset after the collision occurs, and continue from the node N1 in fig. 5A.

In step S523, the controller drives the second sensor to capture the first image and the second image of the workpiece and the clamping portion in different postures, and the controller obtains the first image and the second image from the second sensor. As described above with reference to step S430 of fig. 4, the second sensor 120 captures the workpiece WP and the CL of the clamping portion with different postures, and generates the corresponding first image and second image.

In some embodiments, steps S525 to S535 correspond to step S440 of fig. 4, and the information related to the collision is calculated by comparing the image and the feature data, and the coordinate is corrected accordingly to adjust the posture of the clamping portion.

In step S525, the controller determines whether the clamping portion or the workpiece is displaced or tilted according to the first and second images and the first and second feature data. When the clamping portion or the workpiece is not displaced or tilted, it indicates that the collision detected in steps S511 and S513 is a mechanical error caused by a change in the posture of the pick-and-place device. Therefore, this situation cannot self-eliminate the collision, and step S515 is performed to end the method 500. Otherwise, step S527 is executed. In step S527, the controller determines whether the clamping portion is displaced or skewed according to the second error value. When the clamping portion is displaced or skewed, step S529 is executed. Otherwise, step S533 is executed.

In step S529, the controller determines whether the displacement or the skew of the clamping portion exceeds the allowable range based on the second error value and the allowable range. When the displacement or skew of the clamping portion exceeds the allowable range, it indicates that the posture of the clamping portion is too severe to adjust the pick-and-place device, and step S515 is performed to end the method 500. Otherwise, step S531 is executed.

In step S531, the controller records a coordinate system calibration value according to the second error value. In an embodiment of the invention, after the controller records the coordinate system correction value of the clamping part, the result is applied to the next pick-and-place. In step S533, the controller determines whether the workpiece is shifted or tilted according to the first error value. When the workpiece is displaced or tilted, step S535 is performed. Otherwise, step S539 is executed. In step S535, the controller determines whether the workpiece displacement or skew is out of the tolerance range according to the first error value and the tolerance range.

If the workpiece displacement or skew exceeds the allowable range, it indicates that the attitude of the workpiece is changed too severely, and step 537 to end method 500 are performed. Otherwise, step S539 is executed.

In step 537, the controller drives the clamping portion to discard the workpiece and drives the clamping portion to pick and place the workpiece again according to the first error value. The operation of re-taking and putting the workpiece may include: re-clamping the same workpiece; or to hold another workpiece.

In some embodiments, the method 500 further includes the following steps. The controller determines whether the first error value and the second error value are respectively greater than the reference value according to the first error value, the second error value and the reference value. This reference value is the maximum value of the allowable range described in the above steps S529 and S535. In some embodiments, the reference value is a limit value above an allowable range, which indicates a maximum amount of deflection of the adjustable clamp or the workpiece.

In addition, in some embodiments, the method 500 further includes the following steps. When the first error value and the second error value are both larger than the reference value, the controller generates and sends an alarm signal to the pick-and-place device so as to drive the pick-and-place device to stop the pick-and-place action.

In step S539, since the degree of change in the posture of at least one of the clamping portion and the workpiece is adjustable, the clamping portion is adjusted by the controller, the adjusted workpiece image is superimposed on the corresponding initial image, and the coordinate system is updated. It should be noted that the corrected workpiece coordinate system is limited for the current workpiece pick-and-place operation, and will not be extended to the next pick-and-place operation.

In step S540, when the shape of the workpiece is complex (e.g. i-shaped), the second sensor can capture a third image of the workpiece and the clamping portion. The second sensor can capture a third image on a different plane (e.g., the X-Z plane of fig. 2) to further determine whether the workpiece is shifted. Here, step S540 may be determined whether it is necessary to be executed according to the shape of the workpiece, and is not a necessary step.

Finally, in step S541, the picking and placing operation of the workpiece is executed.

In summary, the workpiece pick-and-place control device and the control method thereof of the machine tool of the invention can detect the sensing signals of the clamping portion and the workpiece by the first sensor and capture the images with different postures by the second sensor when the pick-and-place device or the workpiece is collided, so as to calculate the sensing signals, the images and the corresponding characteristic data by the controller, generate the error value corresponding to the clamping portion or the workpiece, and automatically adjust the posture of the clamping portion and/or the workpiece. Therefore, the invention can self-eliminate the collision condition, so as to facilitate the subsequent operation of taking and placing the workpiece by the machine tool, thereby improving the working efficiency of the machine tool operation.

Although the present invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A workpiece pick-and-place control device of a machine tool, characterized by comprising:

the first sensor is arranged on a clamping part of a pick-and-place device, wherein the clamping part is used for clamping a workpiece to the machine tool, and the first sensor generates a first sensing signal according to the collision state of the clamping part and the workpiece;

a second sensor for capturing images of the workpiece and the clamping part; and

a controller coupled to the first sensor, the second sensor and the clamping portion, the controller configured to:

driving the clamping part to move to a detection area according to the first sensing signal;

enabling the second sensor to capture a first image and a second image of the workpiece and the clamping part in different postures in the detection area;

comparing the first image and the second image with a first characteristic data and a second characteristic data respectively to generate a first error value corresponding to the workpiece and a second error value corresponding to the clamping part, wherein the first characteristic data and the second characteristic data respectively describe the image profiles of the workpiece and the clamping part under the normal condition of not being collided; and

adjusting at least one of the position of the clamping part and the position of the workpiece according to the first error value and the second error value.

2. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 1, wherein the controller is further configured to:

when the taking and placing device is collided, a warning signal is sent and the workpiece taking and placing action of the taking and placing device is stopped, wherein the taking and placing device is used for driving the clamping part to take and place the workpiece.

3. The apparatus of claim 1, wherein the controller is further configured to, during the movement of the clamping portion to the detection area:

and when the clamping part and/or the workpiece is/are judged to be collided according to the first sensing signal, sending a warning signal and stopping the workpiece taking and placing actions of the taking and placing device.

4. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 1, wherein the controller is further configured to:

when the first error value exceeds an allowable range, the clamping part discards the workpiece.

5. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 1, wherein the controller is further configured to:

when the second error value exceeds an allowable range, a warning signal is sent and the workpiece taking and placing actions of the taking and placing device are stopped.

6. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 1, wherein the controller is further configured to:

when the first error value and the second error value are both larger than a reference value, a warning signal is sent and the workpiece taking and placing actions of the taking and placing device are stopped.

7. The apparatus of claim 1, wherein the workpiece has a first angle difference between the first image and the second image, and the clamping portion has a second angle difference between the first image and the second image.

8. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 7, wherein the controller is configured to:

when the clamping part and the workpiece are in the detection area, the second sensor captures the first image of the clamping part and the workpiece in a first posture; and

the clamping part is moved to enable the clamping part and the workpiece to be in a second posture, and the second sensor is enabled to capture a second image of the clamping part and the workpiece in the second posture.

9. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 7, wherein the controller is configured to:

when the clamping part and the workpiece are in the detection area, the second sensor captures images of the clamping part and the workpiece on a first plane to obtain a first image; and

the second sensor captures an image of the clamping part and the workpiece on a second plane to obtain a second image.

10. A workpiece pick-and-place control apparatus for a machine tool as claimed in claim 9, wherein the controller is further configured to:

the second sensor captures images of the clamping part and the workpiece on a third plane to obtain a third image.

11. A workpiece pick-and-place control method of a machine tool is characterized by comprising the following steps:

arranging a first sensor on a clamping part of a pick-and-place device, and enabling the first sensor to generate a first sensing signal according to the collision state of the clamping part and the workpiece;

enabling a second sensor to capture a first image and a second image of the workpiece and the clamping part in different postures in the detection area;

comparing the first image and the second image with a first characteristic data and a second characteristic data respectively to generate a first error value corresponding to the workpiece and a second error value corresponding to the clamping part, wherein the first characteristic data and the second characteristic data respectively describe the image profiles of the workpiece and the clamping part; and

12. A workpiece pick-and-place control method for a machine tool according to claim 11, further comprising:

when the picking and placing device is collided, a warning signal is sent and the workpiece picking and placing action of the picking and placing device is stopped, wherein the picking and placing device is used for driving the clamping part to pick and place the workpiece.

13. The method of claim 11, further comprising, during the movement of the clamping portion to the detection area:

14. A workpiece pick-and-place control method for a machine tool according to claim 11, further comprising:

15. A workpiece pick-and-place control method for a machine tool according to claim 11, further comprising:

16. A workpiece pick-and-place control method for a machine tool according to claim 11, further comprising:

17. The method of claim 11, wherein the workpiece has an angular difference between the first image and the second image, and the clamping portion has an angular difference between the first image and the second image.

18. The method of claim 17, wherein the step of causing the second sensor to capture the first image and the second image of the workpiece and the clamping portion in different postures comprises:

enabling the second sensor to capture the first image of the clamping part and the workpiece in a first posture; and

19. The method of claim 17, wherein the step of enabling the second sensor to capture the first image and the second image of the workpiece and the clamping portion in different postures comprises:

the second sensor captures images of the clamping part and the workpiece on a first plane to obtain a first image; and

20. A workpiece pick-and-place control method for a machine tool as claimed in claim 19, further comprising: