JP2002219631A - Device and method for controlling multi-axis synchronism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling multi-axis synchronism capable of synchronizing a plurality of processing shafts with a feed shaft in a machine tool having the plurality of processing shafts. SOLUTION: This multi-axis machine tool 10 has the plurality of processing shafts 11 and the feed shaft 13 for moving the processing shafts in the same direction and calculates a theoretical position whereat the feed shaft 13 should exist corresponding to each processing shaft 11 and the average position as a target position to be a destination of the feed shaft. The position of the feed shaft 13 is controlled at the target position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-axis synchronous control device and a multi-axis synchronous control method, and more particularly, to controlling the position of a feed axis based on the positions of a plurality of machining axes that perform machining simultaneously. The present invention relates to a multi-axis synchronization control device and a multi-axis synchronization control method.

[0002]

2. Description of the Related Art In recent years, in numerical control machine tools used for drilling taps and drills, there is a method of synchronizing and controlling a machining axis on which a tap bit or a drill bit is mounted and a feed axis for sending the same. Used. By synchronizing the feed speed of the feed shaft, that is, the rotation speed of the motor driving the feed shaft, with respect to one machining axis, machining with a machining speed higher than machining without synchronization can be performed. .

Further, when tapping or drilling a hole in the same plane of a workpiece from the same direction, it is possible to improve the production efficiency by driving a large number of processing axes at a time to perform the processing. it can. For example, there is a type in which tapping and drilling are performed at the same time by the number of axes of the multi-axis head using a machine tool using a multi-axis gear head.

[0004]

However, in the machining by the multi-axis gear head as described above, the method of synchronously controlling the feed axes for a large number of machining axes is not used.

The reason is that the conventional synchronous control method is a method of synchronizing one slave axis with one main axis,
This is because if there are a plurality of machining axes, it is unclear which machining axis should be used as the main axis to synchronize the feed axis, and the synchronization target is not determined.

It is also conceivable that one of a plurality of machining axes is determined as a spindle and the feed axis is synchronized with the spindle. In this case, however, the rotation of a machining axis other than the machining axis determined as the spindle is considered. Even if the speed becomes slower or faster, it is not detected, so that synchronization between the machining axis other than the main spindle and the feed axis is not guaranteed, and there is a possibility that the machining tool or the workpiece is damaged.

Furthermore, it is conceivable to synchronize the machining axis with the feed axis by using a feed axis as a main axis and a plurality of machining axes as minor axes. Because the rotation speed of the machining axis determined as becomes slow or fast, it is difficult for such a machining axis having poor controllability to follow the feed axis.

The present invention has been made in view of the above circumstances, and in a machine tool having a plurality of machining axes, a feed axis can be synchronized without determining one spindle from the plurality of machining axes. It is an object to provide a multi-axis synchronous control device and a multi-axis synchronous control method.

[0009]

The above object of the present invention is achieved by the following means.

(1) The multi-axis synchronous control device according to the present invention
A plurality of machining axes; a feed axis for moving the plurality of machining axes in the same direction; machining axis position detecting means for detecting positions of the plurality of machining axes; and a machining axis for each of the plurality of machining axes. Calculating means for determining a theoretical position where the feed shaft should exist corresponding to the position of the shaft, and calculating a target position of the feed shaft based on the theoretical position; and setting the feed shaft to the calculated target position. And control means for controlling the position of.

(2) The calculating means sets the average position of the theoretical position of the feed axis corresponding to each of the plurality of processing axes detected by the processing axis position detecting means as the target position.

(3) An error between the target position and a theoretical position of the feed axis corresponding to each of the plurality of machining axes is calculated, and it is determined whether or not each error falls within a predetermined allowable range. And stopping means for stopping all of the plurality of machining axes and the feed axis when there is the error that does not fall within a predetermined allowable range.

(4) There is further provided feed axis position detecting means for detecting a current position of the feed axis, and the calculating means calculates the calculated theoretical position and the current position detected by the feed axis position detecting means. An error from the position is calculated, and a position obtained by adding an average value of the error to the current position is set as the target position.

(5) The multi-axis synchronous control method according to the present invention
A multi-axis synchronous control method for controlling a feed axis for moving a plurality of machining axes in the same direction, wherein a step of detecting a position of the plurality of machining axes, and Determining a theoretical position where the feed shaft should exist corresponding to the position of the shaft, and calculating a target position of the feed shaft based on the theoretical position;
Controlling the position of the feed shaft.

[0015]

According to the first aspect of the present invention, based on the theoretical position of the feed shaft corresponding to each position of the plurality of machining axes,
Since the target position of the feed shaft is calculated and the position of the feed shaft is controlled to the target position, the feed shaft can be synchronized with a machine tool having a plurality of machining axes, and the working efficiency can be improved. In addition, since the target position of the feed axis is calculated based on the theoretical position of the feed axis corresponding to the position of each of the plurality of processing axes, it is not necessary to determine one processing axis as the main axis in advance, and The risk of damaging the attached processing tool or the workpiece is extremely reduced. Further, it is not necessary to improve the controllability of the machining axis in order to follow the feed axis with the machining axis as the slave axis, and the multi-axis synchronous control can be performed by adding a simple function.

According to the second aspect of the present invention, since the average position of the theoretical position of the feed axis corresponding to each position of the plurality of processing axes is set as the target position, errors of all the processing axes with respect to the feed axis are equalized. Therefore, the load on the processing tool attached to each processing axis can be equalized, and damage to the processing tool can be reduced.

According to a third aspect of the present invention, an error between the target position and each theoretical position is calculated, and it is determined whether or not each error falls within an allowable range, and there is an error that does not fall within a predetermined allowable range. In this case, since the machining axis and the feed axis are all stopped, breakage of the machining axis, the feed axis, the machining tool attached to the machining axis, the workpiece, and the like can be reliably prevented.

According to a fourth aspect of the present invention, a current position of the feed shaft is detected, an error between the theoretical position of the feed shaft and the detected current position is calculated, and an average value of the error is calculated as the current position. Since the added position is set as the target position, the feed axis can be controlled from the current position to the target position.

According to a fifth aspect of the present invention, a target position of the feed shaft is calculated based on a theoretical position of the feed shaft corresponding to each of a plurality of machining axes, and the position of the feed shaft is set to the target position. Since the control is performed, the feed axis can be synchronized with a machine tool having a plurality of machining axes, and work efficiency can be improved. In addition, since the target position of the feed axis is calculated based on the theoretical position of the feed axis corresponding to the position of each of the plurality of processing axes, it is not necessary to determine one processing axis as the main axis in advance, and The risk of damaging the attached processing tool or the workpiece is extremely reduced. Further, since it is not necessary to improve the controllability of the machining axis in order to follow the feed axis with the machining axis as the slave axis, multi-axis synchronous control is enabled by adding a simple function.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic configuration diagram of a multi-axis machine tool to which the present invention is applied, and FIG. 2 illustrates a function of a controller for synchronously controlling each axis of the machine tool. It is a block diagram for performing.

The multi-axis machine tool 10 includes a plurality of machining axes 11
A machining axis control amplifier 12 for independently controlling the speed of the machining axis 11; a feed axis 13 for moving the plurality of machining axes 11 in the same direction at once; and a feed axis for controlling the speed of the feed axis 13 And a control amplifier 14. The machining axis control amplifier 12 and the feed axis control amplifier 14 are connected to a controller 15 for controlling the machining axis 11 and the feed axis 13 synchronously. In addition, in FIG.
1 is shown as a first machining axis 111, a second machining axis 112 to an Nth machining axis 11N.

Each of the machining shafts 11 is rotated by an independently rotating motor, and an encoder (not shown) for detecting the number of rotations of the motor is provided. These machining axes 11 machine the same surface of the workpiece 100 in the same direction,
For example, tapping is performed.

The machining axis control amplifier 12 supplies electric power to the motor based on a command value given from the controller.

The processing shaft 11 is provided on a movable base 16 and is moved in the direction of the workpiece 100 by the movement of the feed shaft 13.

The feed shaft 13 connects the movable table 16 to the workpiece 100.
A feed shaft motor 17 and a ball screw 1 rotated by the motor 17
Consists of eight. The ball screw 18 meshes with a gear groove (not shown) formed in the bottom of the movable base 16, and the movable base 16 moves forward or backward in the work direction by rotating the ball screw 18. The feed shaft motor 17 includes an encoder (not shown)
Is provided to detect the number of rotations of the motor 17.

The feed axis control amplifier 14 includes the controller 1
5 based on the command value given from
To supply power.

As shown in FIG. 2, the controller 15 includes a machining axis target position calculator 21 for calculating a target position for each machining axis 11, and a controller for each machining axis 11 based on the calculation by the machining axis target position calculator 21. Machining axis speed calculation unit 221 to Nth machining axis speed calculation unit 22N for calculating the respective speeds
(Hereinafter, an arbitrary machining axis speed calculation unit is indicated by reference numeral 22), a feed axis target position calculation unit 23 for calculating a target position of the feed axis, and a feed axis based on the calculation of the feed axis target position calculation unit 23. 13 and a feed axis speed calculation unit 24 for calculating the speed.

The machining axis control amplifier 12 shown in FIG.
2, as many as the number of machining axes 11 from the first machining axis control amplifier 121 to the Nth machining axis control amplifier 12N (hereinafter, an arbitrary machining axis control amplifier is indicated by reference numeral 12). It controls the speeds of the first machining axis motor 251 to the N-th machining axis motor 25N (hereinafter, any machining axis motor is indicated by reference numeral 25) connected to each.
Each machining axis motor 25 rotates the machining axis 11 respectively.

The machining axis target position calculating section 21 calculates an operation amount for each machining axis 11 based on a final target position for each machining axis 11 according to machining, for example, a machining tool attached to the machining axis 11. Machining axis 1 necessary for tapping to the target position based on the movement amount (lead) for one rotation
The number of rotations of 1 is calculated. Then, the machining axis target position calculation unit 21 outputs the calculated motion amount for each machining axis 11 to each machining axis speed calculation unit 22.

The machining axis speed calculation unit 22 calculates the rotation speed command value of the machining axis 11 based on the input amount of motion so that the cutting amount of each machining axis 11 with respect to the workpiece 100 per unit time is the same. Calculate and process axis control amplifier 12
Output to

The machining axis control amplifier 12 includes a machining axis motor 2
Electric power is supplied to the machining axis motor 25 so that the rotation speed 5 becomes the speed command value given from the machining axis speed calculation unit 22.

The machining axis motor 25 is provided with an encoder, and information on the number of revolutions of the machining axis motor 25 is fed back to the machining axis speed calculator 22 via the machining axis control amplifier 12. The processing axis speed calculation unit 22 calculates a rotation speed based on the number of rotations fed back,
Feedback control is performed so that the calculated rotational speed becomes a speed command value as compared with the speed command value.

At the same time, the information on the number of revolutions from the encoder is also transmitted to the feed axis target position calculator 23.

The feed axis target position calculating section 23 stores in advance information on the leads of the machining tools attached to each machining axis 11. Then, the feed axis target position calculation unit 23 calculates the cut amount of the processing shaft 11 based on the information on the lead and the information on the rotation speed of the processing axis motor 25 from the encoder. When the cut amount of the machining shaft 11 and the feed amount of the feed shaft 13 match, the machining shaft 11 and the feed shaft 13 are synchronized, and the position moved by the cut amount is set to the feed shaft 13. Is a position where should exist (hereinafter, referred to as a theoretical position).

The feed axis target position calculator 23 calculates the feed axis 11
In each case, the theoretical position of the feed shaft 13 is determined. Therefore, the theoretical position of the feed shaft 13 by the number of the processing shafts 11 is obtained. Since it is unlikely that all the theoretical positions match, the feed axis target position calculation unit 23 calculates a position obtained by averaging a plurality of obtained theoretical positions, and considers the feed axis taking all the theoretical positions into account. Thirteen movement target positions.

Here, the feed axis target position calculator 23 calculates an error between the target position of the feed shaft 13 and the theoretical position of the feed shaft 13 obtained for each machining axis 11, and calculates each error. Is determined to be within a predetermined allowable range, and if not within the predetermined allowable range, a signal for stopping the feed axis motor 17 is sent to the feed axis speed calculation unit 24, and each machining axis motor 25 is stopped. A signal for causing the machining axis target position calculation unit 21 is output.

If the error falls within a predetermined allowable range, the feed axis target position calculator 23 calculates the amount of movement of the feed shaft 13 based on the target position of the feed shaft 13 and sends it to the feed shaft speed calculator 24. Output.

The feed shaft speed calculation unit 24 calculates a rotation speed to be given to the feed shaft 13 based on the input operation amount,
Processing axis control amplifier 1
Output to 2.

The feed shaft amplifier 14 supplies electric power to the feed shaft motor 17 so that the rotation speed of the feed shaft motor 17 becomes the speed command value given from the feed shaft speed calculator 23.

The feed shaft motor 17 is provided with an encoder, and information on the number of revolutions of the feed shaft motor 17 is fed back to the feed shaft speed calculator 24 via the feed shaft control amplifier 14. The feed axis speed calculation unit 24 calculates a rotation speed based on the number of rotations fed back,
Feedback control is performed so that the calculated rotational speed becomes a speed command value as compared with the speed command value.

The information on the number of revolutions of the feed shaft 17 from the encoder may be transmitted to the feed shaft target position calculator 23. In this case, the feed axis target position calculation unit 23 calculates the feed amount (position) of the feed shaft 17 from the information on the number of revolutions of the feed shaft 17, and calculates the feed amount of the feed shaft 17 and the cut of each machining axis 11. The amount, that is, an error from the theoretical position of the feed shaft 13 corresponding to each processing shaft 11 can be obtained.

If the obtained error does not fall within the predetermined allowable range, the feed axis target position calculating section 23 sends a signal for stopping the feed axis motor 17 to the feed axis speed calculating section 24 and sends the signal to each machining axis. A signal for stopping the motor 25 can be output to the machining axis target position calculation unit 21.

Next, the flow of synchronous control of the feed shaft 13 with respect to each machining shaft 11 will be described.

FIG. 3 is a flowchart showing the flow of synchronous control of the machining axis 11 and the feed axis 13.

First, when the operation of the multi-axis machine tool 10 is started, the machining axis target position calculating section 21 determines the amount of operation for machining each machining axis 11 and outputs it to each machining axis speed calculating section 22. Each machining axis speed calculation unit 22 calculates a rotation speed command value of each machining axis motor 25 based on the amount of movement, and outputs it to each machining axis control amplifier 12 (step S301).

Each machining axis control amplifier 12 controls each machining axis 11 based on the output rotational speed command value, and the feed axis target position calculation unit 23 calculates each machining axis 11 from the encoder.
The number of rotations is monitored (step S302). The feed axis target position calculator 23 calculates the feed axis target position
The theoretical position of the feed shaft 13 is calculated for each machining shaft 11 (Step S303).

Then, the feed axis target position calculator 23 calculates the target position of the feed shaft 13 based on the theoretical position of the feed shaft 13 obtained for each machining axis 11 (step S30).
4) An error between the target position and each theoretical position is calculated (step S305).

If at least one of the calculated errors does not fall within the allowable range (step S306: NO), the feed axis target position calculating section 23 stops the entire machining axis 11 and the feed axis 13. A signal is output to stop all axes (step S307).

On the other hand, if all the calculated errors are within the allowable range (step S306: YES), step S30
The feed axis speed calculator 24 is controlled so that the feed axis moves to the target position calculated in step 4 (step S308).

When the processing is completed (step S309: Y
ES), the multi-axis machine tool 10 ends the operation, and if the machining is not completed (step S309: NO), the processing procedure from step S301 is repeated.

As described above, the error between the target position and each theoretical position is calculated, and it is determined whether each error falls within the allowable range. If there is an error that does not fall within the predetermined allowable range, processing is performed. Since all of the shaft 11 and the feed shaft 13 are stopped, breakage of the processing shaft 11, the feed shaft 13, the processing tool attached to the processing shaft 11, the work 100, and the like can be reliably prevented.

Next, steps S303 to S30
6 and step S308 will be specifically described with reference to FIG.

FIG. 4 is a diagram for explaining the concept of position control of the feed shaft 13 with respect to the position of the machining shaft 11. Here, along the horizontal axis, the left is the advance direction of the machining axis 11, the right is the delay direction, and the distance advanced in the advance direction is the position of the feed axis. The theoretical position of the feed shaft 13 corresponding to each machining axis 11 is indicated by “black short line”, the current position of the feed shaft 13 is indicated by “black long line”, and the target position of the feed axis is “gray long broken line”.
Indicated by

The theoretical position of the feed shaft 13 is as described above.
It is calculated for each machining axis 11, and each machining axis 11
Is the position of the feed shaft 13 that has moved in the advance direction by the same amount as the cutting amount. For example, when the first processing axis 111 moves in the advance direction of 10 μm, the theoretical position of the feed shaft 13 corresponding to the first processing axis 111 also becomes a position advanced by 10 μm in the advance direction.

For example, it is assumed that, in the process of step S303, the theoretical positions corresponding to the first machining axis 111 to the fifth machining axis 115 are calculated at the positions indicated by reference numerals 41 to 45, respectively.

In this case, in the process of step S304, the average of the positions of the theoretical positions 41 to 45 is calculated as the target position 46 of the feed shaft 13 indicated by the gray long broken line.

Then, in the process of step S305, the error between the target position 46 and each of the theoretical positions 41 to 45 is calculated, and in the process of step S306,
It is determined whether each error is within a predetermined allowable range from the target position 46.

In the example shown in FIG. 4, since each error is within an allowable range, for example, ± 10 μm from the target position 46, the movement of the feed shaft 13 is controlled to move to the target position 46 in the process of step S308. You.

It should be noted that the predetermined allowable range from the target position 46 is limited to what degree of error by the machining shaft 11 and the feed shaft 1.
3 is tolerated, and is derived from a model, a calculation formula, and the like obtained from the experimental results. Therefore, since the allowable limit of the error can be determined by experiment, the reliability of the allowable range is high.

The target position 46 is defined by each theoretical position 41
An error between the current position of the feed shaft 13 and each of the theoretical positions 41 to 45 may be calculated instead of the average of the positions of ~ 45, and the average of the errors may be added to the current position of the feed shaft 13 for calculation. .

For example, in the example shown in FIG. 4, the average of the errors is (+ 3-1 + 5-4 + 11) ÷ 5 = + 2.8. It may be calculated as a target position.

As described above, in the above-described embodiment, the target position of the feed shaft 13 is calculated based on the theoretical position of the feed shaft 13 corresponding to the position of each machining shaft 11, and the feed shaft is set to the target position. , The feed shaft 13 can be synchronized with the plurality of processing shafts 11 while preventing damage to each of the processing shafts 11 and the feed shaft 13, thereby improving work efficiency.

Since there is no need to synchronize the feed shaft 13 with one of the machining axes 11 as the main axis, the machining axis 11
The possibility that the processing tool attached to the workpiece or the workpiece is damaged is extremely reduced. Further, it is not necessary to improve the controllability of the machining axis in order to make the machining axis follow the feed axis as a slave axis, and multi-axis synchronous control can be performed by adding a simple function.

Further, since the average position of the theoretical positions is set as the target position, it is possible to equalize the error of all the machining axes with respect to the feed axis, and to equalize the load on the machining tool attached to each machining axis. In addition, it is possible to reduce breakage of the processing tool.

In the above-described embodiment, the average position of the theoretical position of the feed shaft 13 is set as the target position. The average with the target position may be set as the target position.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a multi-axis machine tool to which the present invention is applied.

FIG. 2 is a block diagram for explaining a function of a controller that synchronously controls each axis of the machine tool.

FIG. 3 is a flowchart showing a flow of synchronous control of a processing axis and a feed axis.

FIG. 4 is a diagram for explaining the concept of position control of a feed axis with respect to a position of a processing axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Multi-axis machine tool, 11, 111-11N ... Processing axis, 12, 121-12N ... Processing axis control amplifier, 13 ... Feed axis, 14 ... Feed axis control amplifier, 15 ... Controller, 17 ... Feed axis motor, 22 , 221 to 22N: machining axis speed calculator, 23: feed axis target position calculator, 24: feed axis speed calculator, 25, 251 to 25N: machining axis motor.

Claims (5)

[Claims] A plurality of machining axes; a feed axis for moving the plurality of machining axes in the same direction; machining axis position detecting means for detecting positions of the plurality of machining axes; and a plurality of machining axes. Calculating means for calculating a theoretical position of the feed axis corresponding to the position of the machining axis, and calculating a target position of the feed axis based on the theoretical position; and a calculated target position. And a control means for controlling the position of the feed shaft. 2. The multi-axis synchronization control device according to claim 1, wherein the calculation unit sets an average position of the calculated theoretical positions as the target position. 3. An error between the target position and a theoretical position of the feed axis corresponding to each of the plurality of machining axes is calculated, and it is determined whether each error falls within a predetermined allowable range, 3. The multi-axis synchronization according to claim 1, further comprising a stop unit that stops all of the plurality of machining axes and the feed axis when there is the error that does not fall within a predetermined allowable range. 4. Control device. 4. A feed axis position detecting means for detecting a current position of the feed axis, wherein the calculating means calculates the theoretical position and the current position detected by the feed axis position detecting means. 2. The multi-axis synchronization control device according to claim 1, wherein an error with respect to the current position is calculated, and a position obtained by adding an average value of the error to the current position is set as the target position. 5. A multi-axis synchronous control method for controlling a feed axis for moving a plurality of machining axes in the same direction, comprising: detecting a position of the plurality of machining axes; Calculating the theoretical position of the feed shaft corresponding to the position of the machining axis, and calculating the target position of the feed shaft based on the theoretical position. Controlling the position of the feed shaft. A multi-axis synchronous control method, comprising: