JP2009006372A - Numerical control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a numerical control device for generating the machining timing at which any dimensional variation of machined products does not occur without being affected by the vibration even when the vibration is superposed on a workpiece. <P>SOLUTION: It is discriminated that an amount of the deviation 13 corresponding to the vibration amplitude from the reference position is in a prescribed value suitable for the workpiece machining timing while the movement distance point corresponding to the command position 3 generated by a command position forming unit 2 of a numerical control device 1 is the reference position. The timing signal 11 is generated at the discriminated timing, and the machining timing signal 15 is output by a timing signal output unit 14. A machine performs the machining action following the machining timing signal 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a numerical control device that controls a positioning operation. For example, when a workpiece is processed by positioning control of a controlled object while feeding a fixed dimension by a press machine or the like, an optimum processing timing is detected, and the machine The present invention relates to a numerical control device that outputs the processing timing to the side.

When a workpiece is machined by positioning control of an object to be controlled while feeding at a constant size by a numerical controller, both machining speed and machining accuracy are required. However, in order to improve the processing speed, it is necessary to increase the gain of the servo control system, and in order to improve the processing accuracy, the gain must be decreased so that the workpiece does not vibrate. Therefore, in the prior art, it is difficult to satisfy both control characteristics at the same time.
For this reason, the servo control system gain is optimally adjusted according to the workpiece to be machined. Had to adjust.
In addition, as an example of the prior art related to the present invention, Patent Document 1 shown below describes a method for generating a cutting timing for cutting a transported object while feeding the transported object at a constant size. ing.
JP 2001-270178 A

In the conventional numerical control apparatus, when a vibration is generated when a workpiece is processed, there is a problem that a dimension of a processed product varies due to a position shift corresponding to the vibration width. The situation of this variation is shown in FIG. Therefore, it is necessary to adjust the gain of the servo control system each time so as not to generate vibration in the processed product. However, when the gain is lowered to suppress vibration, the response characteristic of the servo control system is lowered at the same time, resulting in a new problem that the operating rate of the machine is deteriorated.
The present invention has been made in view of such problems, and even when vibration is superimposed on a workpiece, a numerical value that generates a machining timing that is not affected by the vibration and does not cause dimensional variation of a workpiece. An object is to provide a control device.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a command position that generates a command position from a movement distance calculation unit that calculates a movement distance moved by positioning control, a target position, and a movement distance calculated by the movement distance calculation unit. A machine that is a control target by inputting a creation unit, a position command output unit that sequentially outputs the command position as a position command and outputs the position command to a servo motor drive device, and a position feedback signal from a position detector attached to the servo motor. An actual position input unit for obtaining the actual position, a deviation count unit that counts a difference between the command position and the actual position as a deviation amount, and a timing detection unit that detects a workpiece machining timing in the machine from the deviation amount; A timing signal output unit that outputs a timing signal detected by the timing detection unit to a control unit of the machine. In the device,
When the movement distance point with respect to the command position generated by the command position creation unit is set as a reference position, the deviation corresponding to the vibration width from the reference position is less than or equal to a predetermined value within the allowable error range of the workpiece. In this case, a machining timing signal is generated. When the machining timing signal is output by a numerical control device, the machine performs the machining operation.
According to a second aspect of the present invention, the timing detector generates a workpiece machining timing signal when the deviation amount becomes zero.
According to a third aspect of the present invention, the timing detection unit generates a workpiece machining timing signal when the deviation amount becomes 0 and the deviation amount value changes from negative to positive.

  According to the first to third aspects of the present invention, even if vibration or disturbance occurs in the controlled object to be positioned, the vibration width is determined from the deviation amount that is the difference between the command position and the actual position, and the workpiece is determined based on the determination result. The machining timing signal is output, and the machine enters the machining operation according to the machining timing signal to machine the workpiece, so that variations in machining can be eliminated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a functional block diagram of a numerical control apparatus 1 of the present invention. In the figure, a movement distance calculation unit 5 calculates a movement distance 4 moved by positioning control. The command position creation unit 2 generates a command position 3 from the target position and the movement distance 4. The command position 3 is sequentially output to the servo amplifier 16 as the position command 8 by the position command output unit 7 to drive the servo motor 17. The position detection signal 19 of the encoder 18 attached to the servo motor 17 is input to the actual position input unit 6 of the numerical controller 1 via the servo amplifier 16 and is taken in as the actual position 9. From the values of the command position 3 and the actual position 9, the deviation count unit 12 generates a deviation amount 13. The timing detection unit 10 generates the timing signal 11 when the deviation amount 13 becomes a specific value, for example, when it becomes zero. Alternatively, the timing signal 11 is generated at a timing when the deviation amount 13 is 0 and the value of the deviation amount 13 changes from the negative direction to the positive direction.
Here, the negative direction refers to the case where the actual position 9 is at a movement distance point that has not yet reached the target position (command position 3), and the positive direction means the case where the actual position 9 is at a point that has gone too far. .
The timing signal output unit 14 is an interface circuit for outputting the timing signal 11 to the control unit of the machine to be controlled, and outputs it as a machining timing signal 15.
Therefore, the timing signal 11 and the machining timing signal 15 are substantially the same.

FIG. 2 shows a configuration example of a press feeder and its control device in a press machine as a specific application example of the present invention. The operation will be described below.
A position command 8 is output from the numerical controller 1. The output position command 8 is input to the servo amplifier 16 to drive the servo motor 17. The sheet material 24 is fed by driving the entrance roller 22 connected to the servo motor 17 and the exit roller 23.
The position detection signal 19 of the encoder 18 attached to the servo motor 17 is input to the actual position input function 6 of the numerical controller 1 via the servo amplifier 16 and is taken in as the actual position 9. The deviation amount 13 between the actual position 9 and the command position 3 generated by the command position creation unit 2 corresponds to the vibration width from the reference position when the movement distance point corresponding to the command position 3 is used as the reference position. . Accordingly, it is determined that the deviation amount 13 has become a predetermined value suitable for the workpiece machining timing, in other words, when the deviation amount 13 becomes equal to or smaller than a predetermined value within the allowable error range of the workpiece. 15 is output as a control signal for the press machine 20. In response to the timing signal 15, the press drive unit 21 is driven up and down from the press machine 20 to press the sheet material 24.

FIG. 3 is an example in which the present invention is applied to the above-described press machine, and is a view showing an operation and an effect when the sheet material 24 is cut while being fed at constant dimensions. In the same figure, (A) is a figure which shows the case where it processes by the conventional system, and in the conventional process, when a vibration and disturbance generate | occur | produce in the sheet | seat material 24, arbitrary points a and b of the vibration width c Cutting is performed at a point. As a result, a processed product including a dimensional error of the vibration width c is produced as in the d product and the e product, and the processed product varies.
The vibration width shown here corresponds to the movement width from the reference position described above, and is equivalent to the deviation amount 13.
FIG. 3B is a diagram showing a case where processing is performed according to the present invention. In the same figure, when vibration or disturbance occurs in the sheet material 24, the vibration width from the reference position, that is, the deviation amount 13, is determined, and the value of the deviation amount 13 before the movement distance point reaches the reference position is determined. The numerical control device 1 outputs the machining timing signal 15 at the position, that is, at the timing of swinging from the negative side to the positive side that has passed the reference position, and the press machine performs cutting according to the main machining timing signal 15. As a result, processing is performed at the f point and the g point, and a processed product having no variation like the h product and the i product is obtained.
As described above, the numerical control device of the present invention discriminates the machining timing of the workpiece by the position deviation amount and outputs the optimum machining timing, and performs the machining operation of the machine by this machining timing signal. It is possible to make processed products without product variations.

Functional block diagram of the numerical control device of the present invention Configuration diagram of a press feeder and its control device in a press machine of an embodiment of the present invention The figure which shows the effect | action and effect at the time of sheet material fixed-length feed cutting in the block diagram of FIG.

Explanation of symbols

1: Numerical control device 2: Command position creation unit 3: Command position 4: Movement distance 5: Movement distance calculation unit 6: Actual position input unit 7: Position command output unit 8: Position command 9: Actual position 10: Timing detection unit 11: Timing signal 12: Deviation count unit 13: Deviation amount 14: Timing signal output unit 15: Processing timing signal 16: Servo amplifier 17: Servo motor 18: Encoder 19: Position detection signal 20: Press machine 21: Press drive unit 22 : Entrance roller 23: Exit roller 24: Sheet material

Claims (3)

A movement distance calculation unit that calculates a movement distance moved by positioning control, a command position creation unit that generates a command position from a target position and a movement distance calculated by the movement distance calculation unit, and a position of the command position Position command output unit that outputs the command sequentially and outputs it to the servo motor drive unit, and actual position input unit that inputs the position feedback signal from the position detector attached to the servo motor and obtains the actual position of the machine to be controlled A deviation count unit that counts a difference between the command position and the actual position as a deviation amount, a timing detection unit that detects a workpiece machining timing in the machine from the deviation amount, and a timing detection unit In a numerical controller having a timing signal output unit that outputs a timing signal to the control unit of the machine,
When the movement distance point corresponding to the command position generated by the command position creation unit is set as a reference position, the deviation amount corresponding to the vibration width from the reference position is a predetermined value within an allowable error range of the workpiece. A numerical control device that generates a machining timing signal when:   The numerical control device according to claim 1, wherein the timing detection unit generates a workpiece machining timing signal when the deviation amount becomes zero.   The numerical control device according to claim 1, wherein the timing detection unit generates a workpiece machining timing signal when the deviation amount becomes 0 and the deviation amount value changes from negative to positive.

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