JPH08328629A - Method for correcting moving position error and method for correcting and confirming moving position error for nc machine tool - Google Patents

Abstract

PURPOSE: To make a fine moving position correction into the one with high accuracy and to properly perform a moving position correction even for a moving position error including a dynamic error factor by performing a moving position error correction based on calculated dynamic position error amount. CONSTITUTION: NC program execution part 9 of an NC device 7 executes an NC program and outputs a moving command to a driving control part 11. The driving control part 11 controls the rotation control of a servo motor 3. The moving command for the measurement of the moving position of this machine is also outputted to a dynamic position error arithmetic computer 25. The dynamic position error arithmetic part 29 of the dynamic position error arithmetic computer 25 calculates dynamic position error amount by the difference of the machine positional data of a command value data storage part 27 and the measured value data of a measured value data storage part 28. Further, a moving location error correction arthmethic computer 31 calculates the moving position error correction value based on the dynamic position error amount and outputs the correction value data to the correction arithmetic part 33 of the driving control part 11. Namely, dynamic position error amount data is converted into moving position error correction value data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving position error correction method and a moving position error correction confirmation method for an NC machine tool, and more particularly to a moving position error correction based on a moving position of a machine measured by a dynamic displacement measuring method. The present invention relates to a method and a method of confirming a movement position error correction result.

[0002]

2. Description of the Related Art In an NC machine tool, as a method of correcting a moving position error of a machine tool due to a cyclic error of a feed screw pitch, etc., a plurality of measuring points are set at a predetermined pitch and each measuring point is set. The machine is moved, the machine is stopped at each measuring point, the moving position of the machine from the reference position is measured by the measuring means, and each measuring point is corrected from the position error amount at each measuring point based on the measured value. Pitch error point correction method that calculates the moving position error correction amount as point coordinates and sets the moving position error correction amount for each correction point coordinate, and the moving position error at each measuring point from the position error amount at each measuring point A pitch error gradient correction method for calculating a correction amount and setting a movement position error correction amount between measurement points by calculation based on the movement position error correction amount by linear interpolation. It is known.

[0003]

Generally, the number of correction point coordinates set in the pitch error point correction method is generally about several tens of points regardless of the moving stroke of the machine, and in most cases, about 80 points at maximum. Therefore, in this correction method, 5
The correction point coordinates are set at relatively large intervals of about 0 to 100 mm, and fine correction cannot be performed.

As shown in FIG. 8 (a), when the interval between the correction point coordinates, in other words, the error measurement point pitch is large, the error due to the cyclic error cannot be detected and the cyclic error is compensated. I can't. This can be solved by reducing the measurement point pitch of the error as shown in FIG. 8B, but the reduction of the measurement point pitch is also limited due to the problem of the measurement time. It is difficult to obtain measurement data equivalent to the movement of

In the pitch error gradient correction method, the correction accuracy is slightly improved, but since the number of measuring points at the moving position of the machine is the same as in the pitch error point correction method, it is not significantly improved.

Further, in both the pitch error point correction method and the pitch error gradient correction method, since the machine moving position is measured while the machine is stopped, it takes a long time to perform the measurement.
The smaller the measurement point interval for improving the correction accuracy, the longer the measurement takes.

In any case, since the measurement of the moving position of the machine is a static measurement performed by stopping the machine, even if the moving position error due to the static error factor can be corrected, the speed of the machine movement,
It is not possible to correct the moving position error including the dynamic error factors affected by acceleration / deceleration, lost motion, and the like.

Further, conventionally, the result of the movement position error correction cannot be easily confirmed.

The present invention has been made by paying attention to the above-mentioned problems, and it does not take time to measure the moving position of the machine for detecting the moving position error, and fine moving position correction can be performed. Moreover, a moving position error correction method for an NC machine tool that appropriately corrects the moving position error including a dynamic error factor, and further corrects the moving position error in consideration of the droop amount and temperature change. Another object of the present invention is to provide a moving position error correction confirmation method that enables the result of moving position error correction to be easily confirmed.

[0010]

In order to achieve the above-mentioned object, a method of correcting a moving position error of an NC machine tool according to a first aspect of the present invention issues a movement command from a NC device to a drive control section of a servo motor of a machine tool. The moving position of the machine was measured by the dynamic displacement measuring method while the machine was moved according to this moving command, and the machine position indicated by the moving command output to the drive control section and the dynamic displacement measuring method were measured. It is characterized in that the dynamic position error amount is calculated from the difference from the moving position of the machine, and the moving position error is corrected based on this dynamic position error amount.

The dynamic displacement measuring method used in this correction method uses a dynamic laser system to irradiate a laser beam to a beam splitter and a reflecting prism which are fixedly arranged and a reflecting prism which is arranged on a mechanical moving body. Then
There is an application of a laser interferometry method for measuring the moving position of a machine by detecting the frequency difference of the laser beam due to the Doppler effect.

According to the moving position error correcting method of the NC machine tool according to the second aspect, a moving command is output from the NC device to the drive control section of the servo motor of the machine tool, and the moving position of the machine is moved while moving the machine according to this moving command. Is detected by a dynamic displacement measuring method and the rotation amount of the servo motor is detected, and the difference between the moving position of the machine measured by the dynamic displacement measuring method and the machine position indicated by the rotation amount detected value of the servo motor. It is characterized in that the dynamic position error amount is calculated more and the moving position error is corrected based on the dynamic position error amount.

A moving position error correcting method for an NC machine tool according to a third aspect is the moving position error correcting method for an NC machine tool according to the first or second aspect, in which the moving position of the machine is measured by the dynamic displacement measuring method. Is performed for each of the forward and return paths of the machine movement, and the dynamic position error amount is calculated for each of the forward and return paths, and the movement position error correction based on the dynamic position error amount is separately performed for the forward and return paths. It is characterized by doing.

A moving position error correcting method for an NC machine tool according to a fourth aspect is the moving position error correcting method for an NC machine tool according to the first or second aspect, in which the moving position of the machine is measured by the dynamic displacement measuring method. Is performed for each of the forward and return paths of mechanical movement, the dynamic position error amount is calculated for each of the forward and return paths, and the movement position error correction is performed based on the average value of the dynamic position error amounts for the forward and return paths. It is characterized by doing.

A moving position error correcting method for an NC machine tool according to a fifth aspect of the present invention is the moving position error correcting method for an NC machine tool according to any one of the first to fourth aspects, in which a sampling interval of the dynamic position error amount is set. It is characterized in that it is set according to a required correction cycle pitch.

A moving position error correcting method for an NC machine tool according to a sixth aspect is the moving position error correcting method for an NC machine tool according to any one of the first to fifth aspects, in which a higher frequency component than the dynamic position error amount is added. It is characterized in that the moving position error is corrected based on the removed value.

This high frequency component can be removed by signal processing using a low pass filter.

A moving position error correction method for an NC machine tool according to a seventh aspect is the moving position error correction method for an NC machine tool according to any one of the first to sixth aspects, wherein the dynamic position error amount or the dynamic position error is corrected. When the moving position error correction amount based on the position error amount is equal to or more than a set value, the moving position of the machine is measured again by the dynamic displacement measuring method, and the dynamic position error amount is calculated again. .

A method for correcting a moving position error of an NC machine tool according to claim 8 is the method for correcting a moving position error of an NC machine tool according to any one of claims 1 to 7, wherein the dynamic displacement is performed in multi-axis simultaneous movement. The moving position of the machine is measured by the measuring method for each axis and the dynamic position error amount is calculated for each axis, and the moving position error is corrected based on the dynamic position error amount for each axis. The feature is that it is performed for each axis.

A method of correcting a moving position error of an NC machine tool according to a ninth aspect is the method of correcting a moving position error of an NC machine tool according to any one of the first to eighth aspects, wherein the machine moving speed and the position feedback of the servomotor are fed back. The droop amount is calculated from the loop gain and the moving position error is corrected by adding the droop amount.

A moving position error correcting method for an NC machine tool according to a tenth aspect is the moving position error correcting method for an NC machine tool according to any one of the first to ninth aspects, in which a temperature is detected by a temperature detecting means, It is characterized in that the moving position error correction is performed in consideration of the temperature detected by the temperature detecting means.

According to the method for confirming the correction of the moving position error of the NC machine tool according to the eleventh aspect of the present invention, the NC device outputs a moving command corrected for the moving position error to the drive control section of the servo motor of the machine tool, and the machine is driven by this moving command. While moving, the moving position of the machine is measured by the dynamic displacement measuring method, and the movement is calculated from the difference between the machine position indicated by the moving command output to the drive control unit and the moving position of the machine measured by the dynamic displacement measuring method. It is characterized in that the dynamic position error amount is calculated and the dynamic position error amount is output.

[0023]

According to the moving position error compensating method for the NC machine tool according to the first aspect of the present invention, the moving position error is corrected by the laser interference method or the like while the machine is moving according to the moving command output from the NC device to the drive section of the servo motor of the machine tool. The moving position of the machine is continuously measured by the dynamic displacement measuring method, and the difference between the moving position of the machine continuously measured by this dynamic displacement measuring method and the machine position indicated by the movement command output to the servo motor drive is calculated. The dynamic position error amount is calculated, and the moving position error is corrected based on this dynamic position error amount.

According to the moving position error correcting method of the NC machine tool according to the second aspect of the present invention, the moving position error is corrected by the laser interference method or the like while the machine is moving according to the moving command output from the NC device to the drive unit of the servo motor of the machine tool. The machine displacement position is continuously measured by the dynamic displacement measurement method, the rotation amount of the servo motor is detected, and the machine movement position measured by the dynamic displacement measurement method and the machine position indicated by the servo motor rotation amount detection value. Then, the dynamic position error amount is calculated from the difference between and, and the moving position error correction is performed based on this dynamic position error amount.

In the NC machine tool moving position error correcting method according to the third aspect, the moving position of the machine is measured by the above-mentioned dynamic displacement measuring method on each of the forward and backward paths of the machine movement, and the forward and backward paths are individually performed. Then, the dynamic position error amount is calculated, and the moving position error correction is performed on the forward path and the return path based on the individual dynamic position error amount.

In the NC machine tool moving position error correction method according to the fourth aspect, the moving position of the machine is measured by the above-mentioned dynamic displacement measuring method on each of the forward and backward paths of the machine movement, and the forward and backward paths are individually performed. Then, the dynamic position error amount is calculated, and based on the average value of the dynamic position error amounts of the forward and backward passes, the moving position error of the forward and backward passes is corrected.

In the moving position error correcting method for the NC machine tool according to the fifth aspect, the sampling interval of the dynamic position error amount is set to a required correction cycle pitch in order to avoid performing the moving position error correction more than necessary. Set accordingly.

In the moving position error correcting method for an NC machine tool according to a sixth aspect of the invention, the moving position error is corrected based on a value obtained by removing a non-reproducible high frequency component of the dynamic position error amount by signal processing by a low pass filter. Make a correction.

In the NC machine tool moving position error correction method according to the present invention, when the dynamic position error amount or the moving position error correction amount based on the dynamic position error amount is equal to or more than a set value, the moving position of the machine is moved. Assuming that a large transient disturbance occurs during measurement, the moving position of the machine is measured again by the dynamic displacement measuring method to recalculate the dynamic position error amount.

In the NC machine tool moving position error correcting method according to the eighth aspect, the moving position of the machine is measured for each axis by the above-mentioned dynamic displacement measuring method, and the dynamic position error amount for each axis is calculated. Based on this, the movement position error is corrected for each axis.

In the NC machine tool moving position error correction method according to the ninth aspect, the moving position error correction is performed by the dynamic position error amount in consideration of the droop amount.

In the moving position error correcting method for the NC machine tool according to the tenth aspect, the moving position error is corrected by the dynamic position error amount in consideration of temperature.

In the NC machine tool moving position error correction confirmation method according to the eleventh aspect of the present invention, the machine is moved by the moving command after the moving position error correction output from the NC device to the servomotor drive unit of the machine tool. The machine's movement position is continuously measured by the dynamic displacement measurement method using laser interferometry, etc., and the machine's movement position continuously measured by the dynamic displacement measurement method and the machine indicated by the movement command after the movement position error is corrected The dynamic position error amount is calculated from the difference from the position, and this dynamic position error amount is output. From this output information, the moving position error correction result can be quantitatively confirmed and evaluated.

[0034]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a moving position error correcting system used for implementing the moving position error correcting method for an NC machine tool according to the present invention. In FIG. 1, reference numeral 1 indicates a table of the NC machine tool. The table 1 is moved in the left-right direction in FIG. 1 by a feed screw 5 which is rotationally driven by a servo motor 3.

The NC device 7 includes an NC program execution unit 9
And a drive control unit 11 of the servo motor 3.
The NC program execution unit 9 executes the NC program,
The movement command is output to the drive control unit 11. Drive controller 11
Is a rotary encoder 13 connected to the servomotor 3.
The rotation amount of the servo motor 3 is input as a position feedback signal, and the rotation drive of the servo motor 3 is controlled by the semi-closed loop method.

At the time of measuring the moving position of the machine, the dynamic displacement measuring device 15 is attached to the NC machine tool. The dynamic displacement measuring device 15 uses a laser interferometer,
Measuring instrument body 1 including laser output device and laser receiver
7, a fixedly arranged beam splitter 19, a reflecting prism 21 connected to the beam splitter 19, and a movable reflecting prism 23 attached to the table 1.

The dynamic displacement measuring device 15 includes a measuring device main body 17
The laser beam emitted from the laser beam is split by the beam splitter 19, one of the split laser beams is reflected by the reflecting prism 21 to the measuring instrument body 17, and the other laser beam is used as the measuring beam. With the movable reflecting prism 23, the measuring instrument body 17 is folded back.
The difference between the frequency of the measurement light and the frequency of the reference light, which changes due to the Doppler effect due to the change of the optical path length of the measurement light due to the movement of the table 1, is detected, and the movement position of the table 1 is moved while moving the table 1. That is, the moving position of the machine is continuously measured. Hereinafter, this measurement value is referred to as a machine movement position measurement value.

The measurement of the moving position of the machine by the dynamic displacement measuring device 15 is performed by the drive control unit 1 from the NC program execution unit 9.
A movement command is output to 1 and the table 1 is reciprocated by the servo motor 3 by a required required measurement stroke, so that the forward stroke and the backward stroke of the measured stroke are performed.

The movement command for measuring the movement position of this machine is output to the drive control unit 11 and also to the dynamic position error calculation computer 25.

The dynamic position error computing computer 25 includes a command value data storage unit 27, a measured value data storage unit 28,
It has a dynamic position error calculator 29.

The command value data storage unit 27 stores the machine position data indicated by the movement command output by the NC program execution unit 9 as time series data for one measurement stroke.

The measured value data storage unit 28 stores the measured value data of the moving position of the machine by the dynamic displacement measuring device 15 as time series data for one measuring stroke.

The dynamic position error calculation unit 29 stores the machine position data according to the movement command stored in the command value data storage unit 27 and the measurement value data of the machine movement position stored in the measurement value data storage unit 28. And the dynamic position error amount is calculated from the difference between the machine position data in the command value data storage unit 28 and the measurement value data in the measurement value data storage unit 28.

In calculating the dynamic position error amount, the measured value data of the moving position of the machine stored in the measured value data storage unit 28 with respect to the machine position data stored in the command value data storage unit 27 is as follows: Since it has a steady phase delay (time delay) that is determined by servo parameters, feed rate, acceleration / deceleration characteristics, etc. when viewed in time series, this phase delay is identified and the identified phase delay is considered. Each storage unit 2
The data from 7 and 28 are read in association with each other, and the calculation of the dynamic position error amount based on the difference between the machine position data in the command value data storage unit 27 and the measurement value data in the measurement value data storage unit 28 is performed in the same phase. Data.

By measuring the moving position of the machine by the dynamic displacement measuring device 15 in each of the forward and backward paths of machine movement,
The dynamic position error calculation unit 29 individually calculates the dynamic position error value amount for each of the forward and backward paths of machine movement.

The data of the dynamic position error amount calculated by the dynamic error calculation unit 29 is used as the moving position error correction amount calculation computer 3.
Enter 1. Moving position error correction value calculation computer 3
1 calculates a moving position error correction value based on the dynamic position error amount, and outputs the correction value data to the correction calculation unit 33 of the drive control unit 11. That is, the moving position error correction value calculation computer 31 converts the dynamic position error amount data into moving position error correction value data.

The calculation of the moving position error correction value by the dynamic error calculation unit 29 may be performed by any of the following methods.

(1) A moving position error correction value is calculated for each of the forward and backward paths according to the dynamic position error amount of the forward and backward paths of machine movement.

In this case, the optimum movement position error correction is performed for each of the forward and backward paths of machine movement.

(2) A moving position error correction value shared by the forward and return paths is calculated from the average value of the dynamic position error amounts of the forward and return paths of machine movement.

In this case, the memory capacity of the memory for storing the moving position error correction value data can be reduced.

(3) In (1) or (2) above, the sampling interval of the dynamic position error amount for calculating the moving position error correction value is set according to the required correction cycle pitch (correction pitch), and the correction is performed. The moving position error correction value is calculated with the cycle pitch.

In this case, the minimum necessary moving position error correction is performed, and the memory capacity of the memory for storing the moving position error correction value data is reduced.

It is assumed that the high frequency component of the dynamic position error amount is a disturbance component having no reproducibility, and this high frequency component can be removed by signal processing by a low pass filter.

Therefore, the calculation of the moving position error correction value is performed by the dynamic position error amount from which the high frequency component is removed.

If the dynamic position error amount or the moving position error correction amount based on the dynamic position error amount is equal to or greater than the set value, it is considered that a large transient disturbance has occurred at the time of measuring the moving position of the machine and dynamic displacement measurement is performed. The measurement of the movement position of the machine by the device 15, the calculation of the movement position of the machine by the movement position calculation unit 27 of the machine, and the calculation of the dynamic position error amount by the dynamic position error amount calculation unit 29 are performed again.

Next, a procedure for creating correction data for moving position error correction will be described with reference to FIGS. FIG. 2 shows a general flow for creating correction data. In this flow, first, the NC program execution unit 9 outputs a movement command to the drive control unit 11 and the movement position data storage unit 27 of the machine (step 10). As a result, the servo motor 3 is driven and the table 1 moves (step 20).

Next, the machine movement position calculation unit 27 calculates the dynamic position error amount by the dynamic position error calculation routine shown in FIG. 3 (step 30).

Next, the moving position error correction value calculation computer 31 calculates the moving position error correction value by the correction value calculation routine shown in FIG. 4 (step 40).

Next, it is determined whether or not the moving position error correction value is within the allowable accuracy range (step 50). If the moving position error correction value is within the allowable accuracy range, the correction value calculation is completed. On the other hand, when the moving position error correction value is not within the allowable accuracy range, a position command corrected by the moving position error correction value is created (step 60), and step 1
Returning to 0, the position command is output to the drive control unit 11 and the command value data storage unit 27, and thereafter, steps 10 to 50 are performed until the moving position error correction value falls within the allowable accuracy range.
repeat. It should be noted that a limit can be given to the number of repetitions and an alarm can be output if the movement position error correction value does not fall within the allowable accuracy range even if the correction value calculation is performed a predetermined number of times.

Next, the dynamic position error calculation routine shown in FIG. 3 will be described. In this routine, the machine position data indicated by the movement command output from the NC program execution unit 9 to the drive control unit 11 is sequentially stored in the command value data storage unit 27.
One measurement stroke worth of time-series data is stored (step 100), and the measured value data of the moving position of the machine measured by the dynamic displacement measuring device 15 is measured value data storage unit 2.
8, one measurement stroke worth of time series data,
Store (step 110).

When the data storage for one measurement stroke is completed, the machine position data according to the movement command stored in the command value data storage unit 27 and the movement position of the machine stored in the measurement value data storage unit 28 are measured. The value data is read in synchronization with the phase delay determined by the servo parameters, feed rate, acceleration / deceleration characteristics, etc., and the dynamic position error amount is calculated from the difference between the read machine position data and the measured value data (step 120).

Next, the correction value calculation routine shown in FIG. 4 will be described. In this routine, first, data of the dynamic position error amount is input (step 200). Next, it is determined whether or not the correction value calculation mode is the high frequency component removal mode (step 210), whether or not it is the correction mode based on the average value (step 230), and sampling of the dynamic position error amount. It is sequentially determined whether or not the mode is the minimum required mode in which the interval is set according to the required correction cycle pitch and the number of correction data is minimized to the minimum (step 250).

In the high frequency component removal mode, the data of the dynamic position error amount is low-pass filtered to remove the high frequency component from the dynamic position error amount (step 22).
0).

If the correction mode is based on the average value, the average value of the dynamic position error amounts on the forward and backward paths of table movement is calculated (step 240).

If it is the minimum required mode, the required dynamic position error amount data is extracted from the data group of the dynamic position error amount (step 260).

After the data processing according to each mode described above, the moving position error correction value is calculated from the dynamic position error amount (step 270).

In the general flow of FIG. 2, the necessity of repeating the correction value calculation is judged by judging whether or not the moving position error correction value is within the allowable accuracy range, which is shown in FIG. As described above, the necessity of repeating the correction value calculation may be determined by determining whether or not the dynamic position error amount is within the allowable accuracy range. In this case, it is determined in step 35 whether the dynamic position error amount is within the allowable accuracy range, and if the dynamic position error amount is within the allowable accuracy range, the correction value calculation (step 45) is performed. Then, the correction value calculation is completed.
On the other hand, when the dynamic position error amount is not within the allowable accuracy range, the correction value calculation (step 40) is performed, and the position command corrected by the correction value is created (step 60),
Return to step 10.

The correction calculation unit 33 of the drive control unit 11 is
The movement command input from the program execution unit 9 is used to determine the correction amount based on the movement position error correction value provided by the movement position error correction amount calculation computer 31 to perform the movement position error correction.

More specifically, the correction calculation unit 33 calculates the moving position error correction amount by the dynamic error calculation unit 29 for each correction pitch in accordance with the correction start coordinate value and the correction pitch which are set as parameters. As illustrated in FIG. 6, the correction value data R0 to Rn of each correction point is linearly interpolated between the correction points to create a line graph-shaped correction value data string having machine coordinates as addresses. The correction value of the corresponding machine coordinate is read from the correction value data string for each scan time, and the movement position error correction is performed on the movement command input from the NC program execution unit 9 using this correction value as the correction amount.

FIG. 7 shows the measured values of the moving position of the machine after the moving position error correction and before the correction. From FIG. 7, it is understood that when the moving position error correction is performed, the cyclic error with the pitch of about 10 mm is compensated.

Further, the correction calculator 33 calculates the droop amount from the machine movement speed and the loop gain of the position feedback of the servomotor 13, and performs the droop correction together with the movement position error correction. The droop amount is calculated by the following formula.

S = (F / 60) / Kv However, S: droop amount (mm), F: feed speed (mm /
min), Kv: position loop gain (rad / sec) As a result, the position error due to the droop is eliminated in addition to the dynamic position error.

The correction calculation unit 33 detects the temperature of the NC machine tool by the temperature sensor 35 and performs temperature compensation correction in addition to the movement position error correction. This temperature compensation correction is performed by a linear function equation in which a correction coefficient is set according to the detected temperature.

As a result, in addition to the dynamic position error, the position error due to the temperature change is eliminated.

In the multi-axis simultaneous movement, the movement position of the machine is measured by the dynamic displacement measuring device 15 and the dynamic position error amount is calculated by the dynamic position error amount calculating section 29 for each axis. Moving position error correction is performed for each axis based on the dynamic position error amount. Further, droop correction and temperature compensation correction are similarly performed for each axis.

As a result, machining by simultaneous multi-axis movement is also performed accurately.

FIG. 9 shows another embodiment of the moving position error correcting system used for implementing the moving position error correcting method for the NC machine tool according to the present invention. In this embodiment, the dynamic position error calculation computer 25 stores a rotation amount data storage unit 26 that stores the measurement value data of the rotation amount of the servo motor 3 output by the rotary encoder 13 as time series data for one measurement stroke. Measurement value data storage unit 28 that stores the measurement value data of the moving position of the machine by the dynamic displacement measuring device 15 as time series data for one measurement stroke.
And a dynamic position error calculation unit 29.

The dynamic position error calculation unit 29 measures the rotation amount detection value data of the servo motor 3 stored in the rotation amount data storage unit 26 and the moving position of the machine stored in the measurement value data storage unit 28. The value data is read out, and the dynamic position error amount is calculated from the difference between the movement position of the machine indicated by the rotation amount detection value data in the rotation measurement value data storage unit 28 and the measurement value data in the measurement value data storage unit 28.

The measured value data of the moving position of the machine stored in the measured value data storage unit 28 with respect to the detected amount of rotation value data of the servo motor 3 stored in the rotational amount data storage unit 26 is time-series. As seen, since there is a steady phase delay determined by the feed rate, the acceleration / deceleration characteristics, etc., the phase delay degree is identified, and the phase delay degree is identified and the phase delay degree is taken into consideration. Data is read, and the calculation of the dynamic position error amount based on the difference between the machine movement position indicated by the rotation amount detection value data of the rotation amount data storage unit 26 and the measurement value data of the measurement value data storage unit 28 is performed in the same phase. Do with data.

The movement command for measuring the movement position of the machine is output to the drive control unit 11 and also to the dynamic position error calculation computer 25.

The dynamic position error calculation computer 25 includes a command value data storage unit 27, a measured value data storage unit 28,
It has a dynamic position error calculator 29.

The command value data storage unit 27 stores the machine position data indicated by the movement command output by the NC program execution unit 9 as time series data for one measurement stroke.

The measured value data storage unit 28 stores the measured value data of the moving position of the machine by the dynamic displacement measuring device 15 as time series data for one measuring stroke.

The dynamic position error calculation unit 29 is provided with servo parameters such as position loop gain and data such as feed rate and acceleration / deceleration characteristics, and measures and measures the machine position data stored in the machine movement position storage unit 27. Value data storage unit 28
And the measured value data of the moving position of the machine stored by are read, and the dynamic position error amount is calculated from the difference between the machine position data of the measured value data storage unit 28 and the measured value data of the measured value data storage unit 28. .

The measured value data of the moving position of the machine stored in the measured value data storage unit 28 is compared with the measured value data of the moving position of the machine stored in the measured value data storage unit 28 in time series. The steady phase delay (time delay) determined by the servo parameters, feed rate, acceleration / deceleration characteristics, etc.
Since the phase delay degree is identified, the data is read from each of the storage units 27 and 28 in consideration of the identified phase delay degree, and the machine position data and the measurement of the measurement value data storage unit 28 are measured. The calculation of the dynamic position error amount based on the difference from the measured value data of the value data storage unit 28 is performed on the data of the same phase.

Also in this embodiment, the moving position error correction similar to that in the above-described embodiment is performed based on the dynamic position error amount calculated by the dynamic position error calculating section 29.

As a result, the same effect as that of the above embodiment can be obtained in this embodiment.

Next, the method for checking the moving position error correction of the NC machine tool according to the present invention will be described.

The moving position error correction confirmation method is implemented using the system shown in FIG. In performing this moving position error correction confirmation method, the NC of the NC device 1 is
The program execution unit 9 outputs a movement command corrected for the movement position error to the drive control unit 11, and the servo motor 3 drives the table 1. The movement of the table 1 in this case is such that the movement position error is corrected.

The moving position of the table 1 is measured by the dynamic displacement measuring device 15, and the measured value of the mechanical movement value obtained by this measurement is output to the dynamic position error calculating section 29.

Separately from this, the NC program execution unit 9 of the NC device 1 outputs the machine position data indicated by the movement command before the movement position error correction to the command value data storage unit 27,
Machine movement position data is sequentially stored in the command value data storage unit 27.

In the dynamic position error calculation unit 29, the moving position data measured by the dynamic displacement measuring device 15 and stored in the measurement value data storage unit 28 and the machine stored in the command value data storage unit 27 are stored. The dynamic position error amount is calculated from the difference with the position data, and this is output to a display or printed. Also in this case, similarly to the above-described embodiment, each storage unit 27 in consideration of the identified phase delay degree,
The data is read from 28, and the calculation of the dynamic position error amount based on the difference between the machine position data of the measurement value data storage unit 28 and the measurement value data of the measurement value data storage unit 28 is performed with the data of the same phase.

The output information printed or printed out quantitatively shows the difference between the dynamic position error before and after the moving position error correction. Therefore, the moving position error correction result is quantitatively confirmed from this output information. , Can be evaluated.

[0096]

As can be understood from the above description, according to the moving position error correcting method for the NC machine tool according to the first aspect, the dynamic displacement measuring method is used in the state where the machine is actually moving according to the movement command. The moving position of the machine is continuously measured and the amount of dynamic position error is calculated from the difference between the moving position of the machine continuously measured by this dynamic displacement measurement method and the machine position indicated by the movement command output to the servo motor drive. Is calculated and the moving position error is corrected based on this dynamic position error amount,
Since it does not take time to measure the moving position of the machine to detect the moving position error, fine moving position correction is performed with extremely high accuracy, and moving position error including dynamic error factors is also properly corrected. Will be done.

According to the moving position error correcting method of the NC machine tool of the second aspect, the moving position of the machine is continuously measured by the dynamic displacement measuring method while the machine is actually moving by the movement command. Measure with a rotary encoder, calculate the dynamic position error amount from the difference between the measured value of the machine movement position and the machine movement position indicated by the rotation amount detection value of the servo motor, and move based on this dynamic position error amount. Since the position error correction is performed, it does not take time to measure the moving position of the machine for detecting the moving position error, fine moving position correction is performed with high accuracy, and moving position error including dynamic error factors Also, the moving position correction is appropriately performed.

In the NC machine tool moving position error correcting method according to the third aspect, the moving position of the machine is measured by the dynamic displacement measuring method in each of the forward and backward paths of the machine movement, and the forward and backward paths are individually operated. Since the target position error amount is calculated and the moving position error correction is performed based on the individual dynamic position error amount in the forward path and the return path, the optimum moving position error correction is performed in the forward path and the backward path of the machine movement. Become.

In the NC machine tool moving position error correcting method according to the fourth aspect, the moving position of the machine is measured by the dynamic displacement measuring method in each of the forward and backward paths of the machine movement and individually in the forward and backward paths. Since the dynamic position error amount is calculated and the moving position error correction for the forward and backward passes is performed based on the average value of the dynamic position error amounts for the forward and backward passes, the memory capacity of the memory that stores the moving position error correction value data Reduction is achieved.

In the moving position error correcting method for the NC machine tool according to the fifth aspect, since the sampling interval of the dynamic position error amount is set according to the required correction cycle pitch, the minimum necessary moving position error correction is performed. The memory capacity of the memory for storing the moving position error correction value data can be reduced.

In the NC machine tool moving position error correction method according to the sixth aspect, high-frequency components that are not reproducible in the dynamic position error amount are removed by signal processing using a low-pass filter, and the dynamic position after removal of the high-frequency components is removed. Since the moving position error correction is performed based on the error amount, the moving position error correction value does not include a high frequency component that does not have reproducibility, and the moving position error correction is appropriately performed.

In the NC machine tool moving position error correction method according to the seventh aspect, when the moving position error correction amount based on the dynamic position error amount or the dynamic position error amount is equal to or more than a set value, the moving position of the machine is measured. It is assumed that a transient disturbance has occurred, the moving position of the machine is measured again by the dynamic displacement measurement method, and the amount of dynamic position error is calculated again. It is possible to avoid erroneous movement position error correction that is affected by.

In the NC machine tool movement position error correction method according to the eighth aspect, the movement position measurement of the machine by the dynamic displacement measurement method is measured in the multi-axis simultaneous movement, and the dynamic position error amount in the multi-axis simultaneous movement is measured. Since the calculation is performed for each axis and the moving position error correction is performed for each axis based on the dynamic position error amount for each axis, machining by simultaneous multi-axis movement can be performed accurately.

In the moving position error correcting method for the NC machine tool according to the ninth aspect, the droop correction is performed in addition to the moving position error correction based on the dynamic position error amount, and the position accuracy is further improved.

In the moving position error correcting method for the NC machine tool according to the tenth aspect, since the temperature compensation correction is performed in addition to the moving position error correction based on the dynamic position error amount, the position accuracy is maintained regardless of the temperature change. .

In the moving position error correction confirmation method for the NC machine tool according to the eleventh aspect, since the information quantitatively showing the difference between the dynamic position error before and after the correction is accurately obtained, the moving position error can be obtained from this information. The correction result can be quantitatively confirmed and evaluated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a moving position error correcting system used for carrying out a moving position error correcting method and a moving position error correction confirming method of an NC machine tool according to the present invention.

FIG. 2 is a flowchart showing a general flow of correction data creation in a moving position error correction method for an NC machine tool according to the present invention.

FIG. 3 is a flowchart showing a dynamic position error calculation routine in a moving position error correction method for an NC machine tool according to the present invention.

FIG. 4 is a flowchart showing a correction value calculation routine in a moving position error correction method for an NC machine tool according to the present invention.

FIG. 5 is a flowchart showing another general flow of correction data creation in the moving position error correction method for the NC machine tool according to the present invention.

FIG. 6 is a graph showing a procedure for creating a correction value data string and a procedure for determining a correction amount in the moving position error correction method for an NC machine tool according to the present invention.

FIG. 7 is a graph showing measured values of the moving position of the machine after and after the moving position error correction.

8 (a) and 8 (b) are graphs showing a conventional measuring procedure of a moving position error.

FIG. 9 is a block diagram showing another embodiment of the moving position error correcting system used for implementing the moving position error correcting method for the NC machine tool according to the present invention.

[Explanation of symbols]

 1 table 3 servo motor 5 feed screw 7 NC device 9 NC program execution unit 11 drive control unit 13 rotary encoder 15 dynamic displacement measuring device 25 dynamic position error calculation computer 26 rotation amount data storage unit 27 command value data storage unit 28 measurement Value data storage unit 29 Dynamic position error calculation unit 31 Moving position error correction amount calculation computer 33 Correction calculation unit 35 Temperature sensor

[Procedure amendment]

[Submission date] June 15, 1995

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Moving position error correction method for NC machine tool and moving position error correction confirmation method

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadaharu Hayama 2068-3 Ooka, Numazu City, Shizuoka Prefecture, Numazu Plant, Toshiba Machine Co., Ltd. On-site (72) Inventor Hideki Hayashi 2068 Ooka, Numazu City, Shizuoka Prefecture Numazu Office, Toshiba Machine Co., Ltd.

Claims (11)

[Claims] 1. An NC device outputs a movement command to a drive control unit of a servomotor of a machine tool, and the movement position of the machine is measured by a dynamic displacement measuring method while the machine is moved by the movement command, and the drive control is performed. The dynamic position error amount is calculated from the difference between the machine position indicated by the movement command output to the section and the movement position of the machine measured by the dynamic displacement measurement method, and the movement position error is calculated based on this dynamic position error amount. A method for correcting a moving position error of an NC machine tool, which comprises performing a correction. 2. An NC device outputs a movement command to a drive control unit of a servo motor of a machine tool, and while moving the machine according to the movement command, the movement position of the machine is measured by a dynamic displacement measuring method and the servo motor is also used. The amount of rotation of the machine is detected, and a dynamic position error amount is calculated from the difference between the moving position of the machine measured by the dynamic displacement measurement method and the machine position indicated by the detected rotation amount of the servo motor. N characterized by performing moving position error correction based on the amount of position error
C Moving position error correction method for machine tools. 3. The moving position of the machine is measured by the dynamic displacement measuring method in each of the forward and backward paths of the machine movement, and the dynamic position error amount is calculated individually in the forward and backward paths to obtain the dynamic position. The moving position error correction method for an NC machine tool according to claim 1 or 2, wherein the moving position error correction based on the error amount is individually performed for each of the forward path and the backward path. 4. The moving position of the machine is measured by the dynamic displacement measuring method on each of the forward and backward paths of machine movement, and the dynamic position error amount is calculated individually for the forward and backward paths, and the forward and backward paths are calculated. 3. The N according to claim 1, wherein the moving position error correction is performed based on the average value of the dynamic position error amount of N.
C Moving position error correction method for machine tools. 5. The moving position error correction method for an NC machine tool according to claim 1, wherein a sampling interval of the dynamic position error amount is set according to a required correction cycle pitch. . 6. The moving position error of the NC machine tool according to claim 1, wherein the moving position error correction is performed based on a value obtained by removing a high frequency component from the dynamic position error amount. Correction method. 7. When the dynamic position error amount or the moving position error correction amount based on the dynamic position error amount is equal to or more than a set value, the moving position of the machine is measured again by the dynamic displacement measuring method, 7. The moving position error correction method for an NC machine tool according to claim 1, wherein the dynamic position error amount is calculated again. 8. In multi-axis simultaneous movement, the movement position of the machine is measured for each axis by the dynamic displacement measurement method, and the dynamic position error amount is calculated for each axis. 8. The NC according to claim 1, wherein the moving position error correction is performed for each axis based on the dynamic position error amount of.
Method of moving position error correction for machine tools. 9. A droop amount is calculated from a machine moving speed and a loop gain of position feedback of the servo motor,
9. The moving position error correcting method for an NC machine tool according to claim 1, wherein the moving position error correction is performed in consideration of a droop amount. 10. The temperature detecting means detects the temperature, and the moving position error correction is performed in consideration of the temperature detected by the temperature detecting means. NC machine tool moving position error correction method. 11. An NC device outputs a movement command corrected for movement position error to a drive control unit of a servo motor of a machine tool, and the movement position of the machine is moved by the dynamic displacement measuring method while moving the machine according to the movement command. The dynamic position error amount is calculated from the difference between the machine position indicated by the movement command output to the drive control unit and the movement position of the machine measured by the dynamic displacement measuring method, and the dynamic position error amount is calculated. A method for confirming the correction of the moving position error of the NC machine tool, which is characterized by outputting