JP2016215359A - Processing system for adjusting processing tool rotation number and work-piece feeding speed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing system which can maintain a processing quality of a work-piece.SOLUTION: A processing system comprises: a robot 12 having a hand 11; a processor 13 for rotating a processing tool 14; a controller 17 which so controls the processor 13 and the robot 12 as to press a work-piece W gripped by the hand 11 onto the processing tool 14 while rotating the processing tool 14 thereby processing the work-piece; and a force sensor 16 which detects a force acting between the work-piece W and the processing tool 14 when the work-piece W is processed while being pressed onto the processing tool 14 by the robot 12. The controller 17 so adjusts rotation numbers of the processing tool 14 and a work-piece feeding speed of the robot 12 that a detection value of the force detected by the force sensor 16 falls between a specified upper limit threshold and a specified lower limit threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a processing system including a robot that transports a workpiece to a processing machine.

  Conventionally, a workpiece is transferred to a processing machine by a robot, and the workpiece is processed by a processing tool of the processing machine. In particular, in processing operations such as deburring, polishing, and grinding, the workpiece may be processed while pressing the workpiece gripped by the robot hand against a rotating processing tool. In this case, Patent Document 1 discloses a method of adjusting the operation of the arm portion of the robot so that the force acting between the workpiece being processed and the processing tool becomes an appropriate value. Further, Patent Document 1 discloses that a force sensor for measuring such a force is attached to the arm portion of the robot.

JP 2008-142810 A

  By the way, when the robot presses the workpiece against the processing tool of the processing machine, the processing tool may be deteriorated (for example, wear of blades or abrasive grains) due to the material of the workpiece or the processing time. In this case, it is necessary to maintain the machining quality of the workpiece by changing the machining conditions according to the degree of deterioration of the machining tool. For example, it is necessary to perform machining by complexly controlling the rotation speed of the machining tool and the moving speed of the workpiece.

  However, the apparatus disclosed in Patent Document 1 only adjusts the force acting between the workpiece and the processing tool when the workpiece is pressed against the processing tool of the processing machine by the robot. In other words, in Patent Document 1, the rotation speed of the machining tool and the moving speed of the workpiece are not changed according to the degree of deterioration of the machining tool. Therefore, it is difficult to maintain the machining quality of the workpiece when the machining tool deteriorates during machining as described above.

  In view of the above problems, an object of the present invention is to provide a machining system capable of maintaining the machining quality of a workpiece.

  According to the first aspect of the present invention, a robot in which a hand for gripping a workpiece is provided at the tip of the arm, a processing machine having a spindle for rotating the processing tool, a workpiece that rotates the processing tool and is gripped by the hand. Controls the processing machine and the robot so that the workpiece is pressed against the machining tool and acts between the workpiece and the machining tool when the workpiece is pressed against the machining tool by the robot. There is provided a machining system comprising a force sensor for detecting force.

Furthermore, in the processing system of the first aspect,
The control device is configured so that the feed speed of the workpiece pressed against the machining tool by the robot and the rotation speed of the machining tool so that the detected value of the force detected by the force sensor falls within a predetermined upper threshold and a predetermined lower threshold. And has been made to adjust.
The above-described problem is solved by the first aspect. However, the present invention is not limited to the first aspect, and can provide a processing system according to any one of the following second aspect to sixth aspect.

According to the second aspect of the present invention, the processing system of the first aspect described above,
The control device
A determination unit that determines whether or not the detected value of the force detected by the force sensor is within a predetermined upper threshold and a predetermined lower threshold;
When the determination unit determines that the detected force value is equal to or greater than the predetermined upper limit threshold, one of the workpiece feed speed and the processing tool rotation speed is decelerated, and as a result, the detected force value is still When it is equal to or higher than the predetermined upper limit threshold, the other of the workpiece feed speed and the processing tool rotation speed is decelerated, and the determination unit determines that the detected force value is equal to or lower than the predetermined lower limit threshold In this case, one of the workpiece feed speed and the machining tool rotation speed is increased. As a result, if the detected force value is still below the predetermined lower threshold, the workpiece feed speed and the machining tool rotation An operation command unit that increases the other of the speeds is provided.

  According to the third aspect of the present invention, a robot in which a hand for gripping a workpiece is provided at the tip of the arm, a processing machine having a spindle for rotating the processing tool, a workpiece that rotates the processing tool and is gripped by the hand. Controls the processing machine and the robot so that the workpiece is pressed against the machining tool and acts between the workpiece and the machining tool when the workpiece is pressed against the machining tool by the robot. There is provided a machining system comprising a force sensor for detecting force.

Furthermore, it is a processing system of said 3rd aspect,
The control device extracts a specific frequency component from the history of detection values of the force detected by the force sensor, and controls the robot so that the extracted frequency component falls between a predetermined upper threshold and a predetermined lower threshold. The work feed speed pressed against the machining tool and the rotation speed of the machining tool are adjusted.

According to a fourth aspect of the present invention, there is provided the processing system according to the third aspect,
The control device
A frequency analysis unit that extracts a specific frequency component from a history of detected force values detected by the force sensor;
A determination unit that determines whether the frequency component extracted by the frequency analysis unit is between a predetermined upper threshold and a predetermined lower threshold;
When the determination unit determines that the frequency component is equal to or higher than the predetermined upper limit threshold, one of the workpiece feed speed and the processing tool rotation speed is decelerated, and as a result, the frequency component is still the predetermined upper limit threshold. If the above is satisfied, the other one of the workpiece feed speed and the rotation speed of the machining tool is decelerated, and if the determination unit determines that the frequency component is equal to or lower than the predetermined lower limit threshold, the workpiece feed speed is decreased. One of the speed and the rotation speed of the machining tool is increased. As a result, when the frequency component is still below the predetermined lower threshold, the other of the workpiece feed speed and the rotation speed of the machining tool is increased. There is provided a machining system having an operation command section.

  According to a fifth aspect of the present invention, there is provided the machining system according to any one of the first to fourth aspects, wherein the force sensor is disposed between the arm tip of the robot and the hand. .

  According to a sixth aspect of the present invention, there is provided the machining system according to any one of the first to fourth aspects, wherein the force sensor is installed on the spindle of the processing machine.

  According to the seventh aspect of the present invention, in the processing system of any one of the first to sixth aspects, the processing machine selects a processing tool corresponding to the type of workpiece to be processed from a plurality of processing tools, There is provided a machining system further comprising an automatic tool changer for exchanging with a machining tool mounted on a spindle.

  According to the eighth aspect of the present invention, in the machining system of the seventh aspect, at least one of the predetermined upper limit threshold and the predetermined lower limit threshold is used by switching to another value depending on the type of workpiece to be processed. Thus, a machining system is provided.

  According to the first aspect of the present invention, when the robot presses the workpiece against the processing tool and processes the force, the force acting between the workpiece and the processing tool is detected by the force sensor. The control device also adjusts the rotation speed of the machining tool as well as the feed speed of the workpiece pressed against the machining tool by the robot so that the force detection value of the force sensor falls between the predetermined upper threshold and the predetermined lower threshold. To do. That is, as compared with the prior art, the workpiece is processed by complexly adjusting the feed speed of the workpiece pressed against the processing tool by the robot and the rotation speed of the processing tool. Therefore, even if the processing tool is deteriorated during processing, the processing quality of the workpiece can be maintained.

  According to the second aspect of the present invention, the determination unit determines whether or not the force detection value of the force sensor falls between the predetermined upper limit threshold and the predetermined lower limit threshold. Then, the operation command unit decelerates or increases the workpiece feed speed of the robot and the rotation speed of the machining tool based on the determination result of the determination unit. Thus, the force detection value of the force sensor is prevented from being equal to or higher than a predetermined upper limit threshold and lower than a predetermined lower limit threshold. Therefore, similarly to the first aspect, the machining quality of the workpiece can be maintained even if the machining tool is deteriorated during machining.

  According to the third aspect of the present invention, when the workpiece is pressed against the processing tool by the robot, the control device extracts a specific frequency component from the force detection value history of the force sensor. Then, the control device adjusts the feed speed of the workpiece pressed by the robot against the machining tool and the rotation speed of the machining tool so that the extracted frequency component falls within a predetermined upper threshold and a predetermined lower threshold. doing. Thereby, the workpiece can be machined so that the extracted frequency component does not become the frequency of the so-called “chatter” phenomenon, so that the machining quality of the workpiece can be maintained.

  According to the fourth aspect of the present invention, the determination unit determines whether or not the specific frequency component extracted from the force detection value history of the force sensor falls between the predetermined upper limit threshold and the predetermined lower limit threshold. To do. Then, the operation command unit decelerates or increases the workpiece feed speed of the robot and the rotation speed of the machining tool based on the determination result of the determination unit. Accordingly, the frequency component is prevented from being equal to or higher than a predetermined upper limit threshold and lower than a predetermined lower limit threshold. Therefore, as in the third aspect, the “chatter” phenomenon during machining can be avoided and the machining quality of the workpiece can be maintained.

  According to the fifth aspect of the present invention, the force sensor is disposed between the arm tip of the robot and the hand, so that when the robot presses the workpiece against the processing tool, the workpiece and the processing tool The force acting during the period can be detected well.

  According to the sixth aspect of the present invention, as in the fifth aspect, the force acting between the workpiece and the machining tool can be detected well when the robot presses the workpiece against the machining tool. In particular, by arranging a force sensor on the spindle of a processing machine that rotates the processing tool, the wrist of the robot can be made smaller than the processing system of the fifth aspect.

  According to the seventh aspect of the present invention, by providing an automatic tool changer, it is possible to automatically use a processing tool according to the type of work to be performed, such as deburring, polishing, and grinding, or the type of work to be processed. it can.

  According to the eighth aspect of the present invention, even if the machining tool is changed according to the type of workpiece, the machining quality of the workpiece can be maintained satisfactorily.

  These and other objects, features and advantages of the present invention will become more apparent from the detailed description of exemplary embodiments of the present invention illustrated in the accompanying drawings.

It is a figure showing composition of a processing system of a first embodiment. It is a flowchart for demonstrating operation | movement of the processing system of 1st embodiment. It is a flowchart which shows specifically the speed adjustment process in step S14 shown by FIG. 2A. It is a figure which shows the structure of the processing system of 2nd embodiment. It is a figure which shows the structure of the processing system of 3rd embodiment. It is a flowchart for demonstrating the characteristic operation | movement of the processing system of 3rd embodiment. It is a figure which shows the structure of the processing system of other embodiment.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same members are denoted by the same reference numerals. In order to facilitate understanding, the scales of these drawings are appropriately changed. Moreover, the form of the processing system drawn on drawing is an example of this invention, and this invention is not limited to the form drawn on drawing.

(First embodiment)
FIG. 1 is a diagram showing a configuration of a machining system according to the first embodiment.
As shown in FIG. 1, the machining system according to the first embodiment includes a work stage 10 on which a work W is placed at a predetermined position, and a robot 12 on which a hand 11 that holds the work W is attached to the tip of an arm. And a processing machine 13 installed within the movement range of the hand 11 of the robot 12. The robot 12 is a vertical articulated manipulator. Further, the processing machine 13 includes a processing tool 14 that performs processing on the workpiece W, and a processing tool servomotor 15 that is built in a main shaft that rotates the processing tool 14.

  In the present application, a cutter, a grinder, an end mill, or the like is used as the processing tool 14 in order to perform processing operations such as deburring, polishing, and grinding on the workpiece W. Further, after the workpiece W on the workpiece stage 10 is gripped by the hand 11 of the robot 12, the gripped workpiece W is moved by the robot 12 to the processing area of the processing machine 13. Then, by pressing the workpiece W against the rotating processing tool 14, processing operations such as deburring, polishing, and grinding are performed on the workpiece W.

  As shown in FIG. 1, the force sensor 16 is installed at the wrist between the arm tip of the robot 12 and the hand 11. The force sensor 16 is an electric force acting between the workpiece W and the machining tool 14 when the workpiece W is pressed against the rotating machining tool 14 as described above (hereinafter referred to as “acting force”). Output as a signal. For example, as the force sensor 16, a strain gauge attached to an elastically deformed beam, a piezoelectric transducer, or the like is used.

  Furthermore, the processing system of the first embodiment includes a control device 17 that controls the robot 12 and the processing machine 13. As shown in FIG. 1, the control device 17 includes a servo motor control unit 18 (servo amplifier), an operation command unit 19, a determination unit 20, and a force detection value acquisition unit 21.

The force detection value acquisition unit 21 monitors and acquires an electrical signal output from the force sensor 16, for example, a voltage (hereinafter referred to as a force detection value K). And the determination part 20 determines whether the force detection value K acquired by the force detection value acquisition part 21 is settled between the predetermined upper limit threshold value N1 and the predetermined lower limit threshold value N2.
An input unit (not shown) for inputting the lower limit threshold N1 and the upper limit threshold N2 may be connected to the determination unit 20 so that the upper limit threshold N1 and the lower limit threshold N2 can be set and changed.

  The operation command unit 19 outputs a command to operate the robot 12 and the processing machine 13 to the servo motor control unit 18 based on the determination result of the determination unit 20. The command for the processing machine 13 is a command for rotating the processing tool 14 at a predetermined rotation speed. The robot 12 is instructed to move the workpiece W to the machining area of the processing machine 13 by gripping the workpiece W with the hand 11 and to the machining tool 14 rotating the workpiece W in the machining area at a predetermined feed speed and locus. It is to move.

  Then, the servo motor control unit 18 controls the rotation speed of the servo motor 15 that rotates the machining tool 13 based on a command from the operation command unit 19. Further, the servo motor control unit 18 controls the conveyance of the workpiece W from the workpiece stage 10 to the processing tool 14 based on a command from the operation command unit 19. That is, the servo motor control unit 18 controls robot servo motors (not shown) that respectively drive the axes of the joints of the robot 12.

Next, operation | movement of the processing system of 1st embodiment is demonstrated.
FIG. 2A is a flowchart for explaining the operation of the machining system of the first embodiment.
The operation command unit 19 of the control device 17 outputs an operation command to the robot 12 and the processing machine 13 to the servo motor control unit 18. The servo motor control unit 18 controls a servo motor (not shown) for each axis of the robot 12 to operate the hand 11 and the robot 12 as instructed.

  In the operation command to the robot 12, first, the robot 12 grips and removes an unprocessed work W from the work stage 10 with the hand 11 of the robot 12 (step S <b> 11 in FIG. 2A). Next, the robot 12 moves the workpiece W to a machining start point in the processing machine 13 (step S12 in FIG. 2A). Subsequently, the robot 12 moves the workpiece W gripped by the hand 11 from the machining start point toward the machining tool 14 at a predetermined feed speed and locus. At this time, the servo motor control unit 18 starts rotating the processing tool servo motor 15 of the processing machine 13 at a predetermined rotation speed (step S13 in FIG. 2A). As described above, the workpiece W is pressed against the rotating processing tool 14, and processing operations such as deburring, polishing, and grinding of the workpiece W are started.

  After step S <b> 13, the force detection value acquisition unit 21 of the control device 17 monitors the force detection value K of the force sensor 16. During monitoring of the force detection value K, the operation command unit 19 adjusts the workpiece W feed speed of the robot 12 and the rotation speed of the processing tool 14 based on the force detection value K of the force sensor 16 (step S14 in FIG. 2A). ). Thereafter, step S4 is continued until the workpiece W reaches the machining end point in the processing machine 13, and when the workpiece W reaches the machining end point, the machining operation is finished (step S15 in FIG. 2A).

Here, with reference to FIG. 2B, the processing content in step S14 will be described in more detail. FIG. 2B is a flowchart specifically showing the speed adjustment processing in step S14 shown in FIG. 2A.
When step S14 is started, as shown in FIG. 2B, first, the force detection value acquisition unit 21 of the control device 17 acquires the force detection value K of the force sensor 16 (step S21). Next, the determination unit 20 of the control device 17 compares the force detection value K with a predetermined upper limit threshold N1 (step S22).

  If the force detection value K is greater than or equal to the predetermined upper limit threshold N1 in step S22, the operation command unit 19 decelerates the feed speed of the workpiece W by a minute first speed amount (step S23). If the force detection value K is smaller than the predetermined upper threshold N1 in step S22, the process proceeds to step S27. Steps S27 and after will be described later.

  After step S23, the force detection value acquisition unit 21 of the control device 17 acquires the force detection value K of the force sensor 16 again (step S24). Furthermore, the determination unit 20 of the control device 17 compares the force detection value K acquired in step S24 with a predetermined upper limit threshold N1 (step S25).

  As a result, when the force detection value K acquired in step S24 is still greater than or equal to the predetermined upper limit threshold N1, the operation command unit 19 reduces the rotational speed of the processing tool 14 by a minute second speed amount (step S26). Then, it returns to step S21 and repeats step S21-step S26 until the force detection value K in step S24 becomes smaller than the predetermined upper limit threshold value N1. If the force detection value K acquired in step S24 is smaller than the predetermined upper limit threshold N1, the process proceeds to step S27.

  In step S27, the determination unit 20 of the control device 17 compares the force detection value K acquired in step S21 or step S24 with a predetermined lower limit threshold N2 (step S27). As a result, when the force detection value K acquired in step S21 or step S24 is equal to or less than the predetermined lower limit threshold N2, the operation command unit 19 sets the feed speed of the workpiece W of the robot 12 by a minute first speed amount. The speed is increased (step S28).

  If the force detection value K acquired in step S21 or step S24 is greater than the predetermined lower limit threshold N2, it can be determined that the machining quality of the workpiece W is maintained normally. Therefore, the operation command unit 19 ends the speed adjustment process and proceeds to step S15 shown in FIG. 2A.

  After step S28, the force detection value acquisition unit 21 of the control device 17 acquires the force detection value K of the force sensor 16 again (step S29). Further, the determination unit 20 of the control device 17 compares the force detection value K acquired in step S29 with a predetermined lower limit threshold N2 (step S30).

  As a result, when the force detection value K acquired in step S29 is still less than or equal to the predetermined lower threshold N2, the operation command unit 19 increases the rotational speed of the processing tool 14 by a minute second speed amount ( Step S31). Then, it returns to step S21 and repeats step S21-step S31 until the force detection value K in step S29 becomes larger than the predetermined lower limit threshold value N2. Further, when the force detection value K acquired in step S29 is larger than the predetermined lower limit threshold N2, it can be determined that the machining quality of the workpiece W is maintained normally. Therefore, the operation command unit 19 ends the speed adjustment process and proceeds to step S15 shown in FIG. 2A.

  As described above, the rotational speed of the processing tool 14 and the feed speed of the workpiece W of the robot 12 are adjusted in a complex manner so that the force detection value K of the force sensor 16 falls within the upper limit threshold value N1 and the lower limit threshold value N2. As a result, the workpiece W is processed. Therefore, the processing quality of the workpiece W can be maintained even when the processing tool W deteriorates due to the material or processing time of the workpiece W (for example, wear of blades or abrasive grains).

  Of course, the upper limit threshold value N1, the lower limit threshold value N2, the minute first speed amount when the feed speed of the workpiece W with respect to the machining tool 14 is increased or decreased, and the rotation speed of the machining tool 14 are increased or decreased. The minute second speed amount when decelerating can be changed before workpiece processing.

  Further, the upper limit threshold value N1 and the lower limit threshold value N2 may be determined by performing trial machining of the workpiece W in advance as follows. For example, first, based on the material and shape of the workpiece W, the rotation speed of the machining tool 14 and the feed speed of the workpiece W with respect to the machining tool 14 are set. Then, the robot 12 performs trial machining of the workpiece W by pressing the workpiece W against the machining tool 14 rotating at the set rotation speed at the set feed speed. After the trial machining, the setter of the machining system inspects the machining quality of the workpiece W. The setter performs such an inspection by gradually increasing the set value of the feed speed of the workpiece W from zero, and acquires the force detection value K of the force sensor 16 for each inspection. As a result, the maximum value of the force detection values K of the force sensor 16 that are recognized to have normal machining quality of the workpiece W can be determined as the upper limit threshold N1, and the minimum value can be determined as the lower limit threshold N2.

In the first embodiment described above, the rotational speed of the machining tool 14 is adjusted after adjusting the feed speed of the workpiece W with respect to the machining tool 14 (see S23, S26, S28, and S31 in FIG. 2B). However, in the present invention, the order of adjusting the workpiece feeding speed and the processing tool rotation speed may be reversed. That is, after adjusting the rotational speed of the processing tool 14 in step S23 or step S28 of FIG. 2B, the feed speed of the workpiece W to the processing tool 14 may be adjusted in step S26 or step S31 of FIG. 2B.
Further, in step S23 of FIG. 2B, both the rotational speed of the machining tool 14 and the feed speed of the workpiece W to the machining tool 14 are decelerated. In step S28 of FIG. 2B, the rotational speed of the machining tool 14 and the workpiece with respect to the machining tool 14 are reduced. Both feed rates of W may be increased.

(Second embodiment)
Next, a second embodiment will be described. However, here, the same constituent elements as those in the first embodiment will be omitted using the same reference numerals. Therefore, only differences from the components of the first embodiment will be described below.
FIG. 3 is a diagram showing a configuration of a machining system according to the second embodiment.
In the first embodiment shown in FIG. 1, the force sensor 16 is installed at the wrist between the arm tip of the robot 12 and the hand 11. However, the force sensor 16 may be installed in the processing machine 13 instead of the robot 12.

  That is, in the second embodiment, the force sensor 16 is installed on the main shaft of the processing machine 13 as shown in FIG. More specifically, it is disposed between the machining tool servomotor 15 and the machining head 22 that is rotatable by the machining servomotor 15. The processing tool 14 is detachably attached to the processing head 22.

  According to the second embodiment, since the force sensor 16 is installed on the spindle of the processing machine 13, the wrist portion of the robot 12 can be reduced in size compared to the first embodiment. However, in the present invention, the installation location of the force sensor 16 is not limited. As long as the working force between the workpiece W and the processing tool 14 can be satisfactorily detected when the workpiece W is pressed against the rotating processing tool 14, the force sensor 16 may be installed anywhere.

  Other configurations are the same as those in the first embodiment. The operation of the machining system of the second embodiment is also the same as the operation of the machining system of the first embodiment described above (see FIGS. 2A and 2B).

(Third embodiment)
Next, a third embodiment will be described. However, here, the same constituent elements as those in the first embodiment will be omitted using the same reference numerals. Therefore, only differences from the components of the first embodiment will be described below.
FIG. 4 is a diagram showing a configuration of a machining system according to the third embodiment.
In the third embodiment, as shown in FIG. 4, a frequency analysis unit 23 is further provided in the control device 17.

  More specifically, the frequency analysis unit 23 performs frequency analysis, for example, FFT (Fast Fourier Transform) analysis on the history of the force detection value K of the force sensor 16 monitored by the force detection value acquisition unit 21. Then, the frequency analysis unit 23 decomposes the history of the force detection value K of the force sensor 16 into a plurality of frequency components by FFT analysis, extracts a specific frequency component F from the plurality of frequency components, and determines it to the determination unit 20. Send.

  The specific frequency component F to be extracted is a load fluctuation frequency when the workpiece W is pressed against the processing tool 14 for processing. If the frequency of such load fluctuations exceeds a predetermined frequency range, it can be considered that a so-called “chatter” phenomenon has occurred in the workpiece W. In the present embodiment, the frequency component F is extracted from the history of the force detection value K of the force sensor 16 in order to avoid the “chatter” phenomenon.

Therefore, the determination unit 20 determines whether or not the specific frequency component F transmitted from the frequency analysis unit 23 is within the predetermined upper limit threshold N3 and the predetermined lower limit threshold N4.
In order to make it possible to change the setting of the upper threshold N3 and the lower threshold N4, the determination unit 20 may be connected to an input unit (not shown) for inputting the lower threshold N3 and the upper threshold N4.

  The operation command unit 19 outputs a command to operate the robot 12 and the processing machine 13 to the servo motor control unit 18 based on the determination result of the determination unit 20. The command for the processing machine 13 is a command for rotating the processing tool 14 at a predetermined rotational speed. The robot 12 is instructed to move the workpiece W to the machining area of the processing machine 13 by gripping the workpiece W with the hand 11 and to the machining tool 14 rotating the workpiece W in the machining area at a predetermined feed speed and locus. It is to move.

  Then, the servo motor control unit 18 controls the rotation speed of the servo motor 15 that rotates the machining tool 13 based on a command from the operation command unit 19. Further, the servo motor control unit 18 controls the conveyance of the workpiece W from the workpiece stage 10 to the processing tool 14 based on a command from the operation command unit 19. That is, the servo motor control unit 18 controls the servo motor 24 for the robot that drives the axis of each joint of the robot 12.

  About another structure, it is the same as the structure demonstrated in 1st embodiment (FIG. 1) or 2nd embodiment (FIG. 3). The installation location of the force sensor 16 of the third embodiment may be between the arm tip of the robot 12 and the hand 11 or between the processing tool servomotor 15 of the processing machine 13 and the processing head 22. .

Next, operation | movement of the processing system of 3rd embodiment is demonstrated.
The operation of the machining system of the third embodiment is basically the same as the operation steps S11 to S15 of the first embodiment shown in FIG. 2A. However, since the frequency analysis unit 23 is added in the control device 17 as described above, the processing content in step S14 is partially different from the first embodiment. Therefore, only this point will be described in detail with reference to FIG.

  FIG. 5 is a flowchart for explaining characteristic operations of the machining system according to the third embodiment. In particular, FIG. 5 is a flowchart specifically showing the speed adjustment process of step S14 shown in FIG. 2A as a third embodiment.

  When the speed adjustment process is started as shown in FIG. 5, first, the frequency analysis unit 23 of the control device 17 sets the force detection value K of the force sensor 16 monitored and acquired by the force detection value acquisition unit 21. An FFT (Fast Fourier Transform) analysis is performed on the history. Then, the frequency analysis unit 23 decomposes the history of the force detection value K of the force sensor 16 into a plurality of frequency components by FFT analysis, and extracts a specific frequency component F from the plurality of frequency components (step S51).

  Next, the determination unit 20 of the control device 17 compares the frequency component F with a predetermined upper limit threshold N3 (step S52). If the frequency component F is greater than or equal to the predetermined upper limit threshold N3 in step S52, the motion command unit 19 decelerates the feed speed of the work W of the robot 12 by a minute first speed amount (step S53). If the frequency component F is smaller than the predetermined upper limit threshold N3 in step S52, the process proceeds to step S57. Steps S57 and after will be described later.

  After step S53, again, the frequency analysis unit 23 decomposes the history of the force detection value K of the force sensor 16 into a plurality of frequency components by FFT analysis, and extracts a specific frequency component F from the plurality of frequency components. (Step S54). Further, the determination unit 20 of the control device 17 compares the frequency component F extracted in step S54 with a predetermined upper limit threshold N3 (step S55).

  As a result, when the frequency component F extracted in step S54 is still not less than the predetermined upper limit threshold N3, the operation command unit 19 reduces the rotational speed of the processing tool 14 by a minute second speed amount (step S56). ). Then, it returns to step S51 and repeats step S51-step S56 until the frequency component F extracted in step S54 becomes smaller than the predetermined upper limit threshold value N3. If the frequency component F extracted in step S54 is smaller than the predetermined upper threshold N3, the process proceeds to step S57.

  In step S57, the determination unit 20 of the control device 17 compares the frequency component F extracted in step S51 or step S54 with a predetermined lower threshold N4 (step S57). As a result, when the frequency component F extracted in step S51 or step S54 is equal to or less than the predetermined lower limit threshold N4, the operation command unit 19 increases the feed speed of the work W of the robot 12 by a minute first speed amount. Speed up (step S58).

  If the frequency component F extracted in step S51 or step S54 is greater than the predetermined lower limit threshold N4, it can be determined that the machining quality of the workpiece W is maintained normally. Therefore, the operation command unit 19 ends the speed adjustment process and proceeds to step S15 shown in FIG. 2A.

  After step S58, the frequency analysis unit 23 again decomposes the history of the force detection value K of the force sensor 16 into a plurality of frequency components by FFT analysis, and extracts a specific frequency component F from the plurality of frequency components. (Step S59). Further, the determination unit 20 of the control device 17 compares the frequency component F extracted in step S59 with a predetermined lower limit threshold N4 (step S60).

  As a result, when the frequency component F extracted in step S59 is still less than or equal to the predetermined lower threshold N4, the operation command unit 19 increases the rotational speed of the processing tool 14 by a minute second speed amount (step S61). Then, it returns to step S51 and repeats step S51-step S61 until the frequency component F extracted in step S59 becomes larger than the predetermined lower limit threshold value N4. If the frequency component F extracted in step S59 is larger than the predetermined lower limit threshold N2, it can be determined that the machining quality of the workpiece W is kept normal. Therefore, the operation command unit 19 ends the speed adjustment process and proceeds to step S15 shown in FIG. 2A.

  As described above, the rotational speed of the processing tool 14 and the work W of the robot 12 are adjusted so that the frequency component F extracted from the history of the force detection value K of the force sensor 16 is within the upper threshold N3 and the lower threshold N4. The workpiece W is processed by complexly adjusting the feed rate. Since the workpiece W can be machined so that the frequency component F does not become the frequency of the so-called “chatter” phenomenon, the machining quality of the workpiece W can be maintained.

  Of course, the upper limit threshold value N3, the lower limit threshold value N4, the minute first speed amount when the feed speed of the workpiece W with respect to the machining tool 14 is increased or decreased, and the rotation speed of the machining tool 14 are increased or decreased. The minute second speed amount when decelerating can be changed before workpiece processing. Moreover, it is preferable that the upper limit threshold value N3 and the lower limit threshold value N4 are determined by performing trial machining of the workpiece W in advance as in the first embodiment.

In the third embodiment described above, the rotational speed of the machining tool 14 is adjusted after adjusting the feed speed of the workpiece W with respect to the machining tool 14 (see S53, S56, S58, and S61 in FIG. 5). However, in the present invention, the order of adjusting the workpiece feeding speed and the processing tool rotation speed may be reversed. That is, after adjusting the rotation speed of the machining tool 14 in step S53 or step S58 in FIG. 5, the feed speed of the workpiece W with respect to the machining tool 14 may be adjusted in step S56 or step S61 in FIG.
Further, in step S53 in FIG. 5, both the rotational speed of the machining tool 14 and the feed speed of the workpiece W with respect to the machining tool 14 are reduced, and in step S58 in FIG. 5, the rotational speed of the machining tool 14 and the workpiece with respect to the machining tool 14 are reduced. Both feed rates of W may be increased.

(Other embodiments)
In the processing systems of the first embodiment, the second embodiment, and the third embodiment described above, it is preferable that the processing tool 14 mounted on the spindle of the processing machine 13 can be replaced with another processing tool. . FIG. 6 is a diagram showing a configuration of a machining system in which the machining tool 14 can be replaced as another embodiment of the present invention. However, the same components as those in the processing systems of the above-described embodiments are not different from those already described, and the same reference numerals are used in FIG.

  More specifically, in the processing system shown in FIG. 6, the processing machine 13 includes an automatic tool changer 25 that replaces the processing tool 14 mounted on the spindle with another processing tool. A tool stocker 26 is installed near the processing machine 13. A plurality of processing tools are stored in the tool stocker 26 so that processing tools can be properly used according to processing operations such as deburring, polishing, and grinding, and types of workpieces W to be processed. For example, when information on a workpiece W to be machined is input, the automatic tool changer 25 selects a machining tool corresponding to the type of the workpiece W to be machined from a plurality of machining tools in the tool stocker 26, and The machining tool 14 mounted on the 13 main shafts is exchanged.

  In the machining system shown in FIG. 6 as well, when the workpiece 12 is pressed against the machining tool 14 by the robot 12, the force sensor 16 detects the force acting between the workpiece W and the machining tool 14. To do. The control device 17 (not shown in FIG. 6) of the machining system also has a detection value of the force obtained by the force sensor 16 as a predetermined upper threshold and a predetermined value as described in the above embodiments. The feed speed of the workpiece W pressed against the machining tool 14 by the robot 12 and the rotation speed of the machining tool 14 are adjusted so as to be within the lower threshold. In particular, in the machining system shown in FIG. 6, it is preferable that at least one of the predetermined upper limit threshold and the predetermined lower limit threshold is switched to another value depending on the type of the workpiece W to be processed. . Thereby, even if the machining tool 14 is changed according to the type of the workpiece W, the machining quality of the workpiece W can be maintained satisfactorily.

  6 shows an example in which the automatic tool changer 25 and the tool stocker 26 are applied to the configuration of the machining system (see FIG. 3) of the second embodiment. However, the automatic tool changer 25 and the tool stocker 26 are shown. May be applied to the configuration of the processing system of the first embodiment (see FIG. 1).

  As mentioned above, although typical embodiment was shown, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the thought of this invention, the above-mentioned embodiment can be changed into various forms, structures, materials, etc. is there.

DESCRIPTION OF SYMBOLS 10 Work stage 11 Hand 12 Robot 13 Processing machine 14 Processing tool 15 Servo motor for processing tools 16 Force sensor 17 Controller 18 Servo motor control part 19 Operation command part 20 Judgment part 21 Force detection value acquisition part 22 Processing head 23 Frequency analysis part 24 Servo motor 25 Automatic tool changer 26 Tool stocker

Claims (8)

A robot (12) having a hand (11) for gripping the workpiece (W) provided at the tip of the arm;
A processing machine (13) having a spindle for rotating the processing tool (14);
The processing tool (14) and the robot (13) are rotated so that the workpiece (W) gripped by the hand (11) is pressed against the processing tool (14) for processing. 12) and a control device (17) for controlling
A force acting between the workpiece (W) and the processing tool (14) is detected when the workpiece (W) is pressed against the processing tool (14) by the robot (12). A force sensor (16) for performing,
The control device (17)
The workpiece pressed against the processing tool (14) by the robot (12) so that the detected value of the force detected by the force sensor (16) falls within a predetermined upper threshold and a predetermined lower threshold. A processing system in which the feed speed of (W) and the rotational speed of the processing tool (14) are adjusted. The control device (17)
A determination unit (20) for determining whether or not the detected value of the force detected by the force sensor (16) falls within a predetermined upper limit threshold and a predetermined lower limit threshold;
If the determination unit (20) determines that the detected force value is equal to or greater than the predetermined upper limit threshold value, the feed speed of the workpiece (W) and the rotation speed of the machining tool (14) One is decelerated, and as a result, when the detected value of the force is still greater than or equal to the predetermined upper limit threshold, the other of the feed speed of the workpiece (W) and the rotational speed of the machining tool (14) is decelerated. Further, when the determination unit (20) determines that the detection value of the force is equal to or less than the predetermined lower limit threshold, the feed speed of the workpiece (W) and the rotation of the machining tool (14) One of the speeds is increased, and as a result, when the detected value of the force is still below the predetermined lower limit threshold, the feed speed of the workpiece (W) and the rotational speed of the machining tool (14) Speed up the other Having the operation command unit (19), a to, processing system according to claim 1. A robot (12) having a hand (11) for gripping the workpiece (W) provided at the tip of the arm;
A processing machine (13) having a spindle for rotating the processing tool (14);
The processing tool (14) and the robot (13) are rotated so that the workpiece (W) gripped by the hand (11) is pressed against the processing tool (14) for processing. 12) and a control device (17) for controlling
A force acting between the workpiece (W) and the processing tool (14) is detected when the workpiece (W) is pressed against the processing tool (14) by the robot (12). A force sensor (16) for performing,
The control device (17)
A specific frequency component is extracted from the history of detection values of the force detected by the force sensor (16), and the extracted frequency component falls within a predetermined upper limit threshold and a predetermined lower limit threshold. A machining system in which a feed speed of the workpiece (W) pressed against the machining tool (14) by the robot (12) and a rotation speed of the machining tool (14) are adjusted. The control device (17)
A frequency analysis unit (23) for extracting a specific frequency component from a history of detection values of the force detected by the force sensor (16);
A determination unit (20) for determining whether or not the frequency component extracted by the frequency analysis unit (23) is within a predetermined upper limit threshold and a predetermined lower limit threshold;
When the determination unit (20) determines that the frequency component is equal to or greater than the predetermined upper limit threshold, one of the feed speed of the workpiece (W) and the rotation speed of the machining tool (14) is determined. As a result, if the frequency component is still greater than or equal to the predetermined upper limit threshold, the other of the feed speed of the workpiece (W) and the rotational speed of the machining tool (14) is decelerated, When the determination unit (20) determines that the frequency component is equal to or less than the predetermined lower limit threshold, one of the feed speed of the workpiece (W) and the rotation speed of the machining tool (14) is determined. As a result, when the frequency component is still below the predetermined lower limit threshold, the other one of the feed speed of the workpiece (W) and the rotation speed of the machining tool (14) is increased. Having the operation command unit (19), a to, processing system according to claim 3.   The processing system according to any one of claims 1 to 4, wherein the force sensor (16) is installed between the arm tip of the robot (12) and the hand (11).   The said force sensor (16) is a processing system as described in any one of Claim 1 to 4 installed in the said main axis | shaft of the said processing machine (13).   The processing machine (13) selects a processing tool corresponding to the type of the workpiece (W) to be processed from a plurality of processing tools and replaces it with the processing tool (14) mounted on the spindle. The processing system according to any one of claims 1 to 6, further comprising a device (25).   The machining system according to claim 7, wherein at least one of the predetermined upper limit threshold and the predetermined lower limit threshold is used by switching to another value according to the type of the workpiece (W) to be machined.

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