JP2006195664A - Numerical control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a follow-up error, such as an overshoot or a follow-up delay, caused at a reversal of a feed shaft even if the movement state of the feed shaft varies between the feed shaft reversal and lost motion compensation completion to cause an inconstant speed change in the feed shaft. <P>SOLUTION: For a speed or torque compensation amount computed in accordance with the acceleration of a feed shaft at a reversal, a compensation amount calculation means detects feed shaft movement states before and after the reversal, calculates a factor by a predetermined rule from the feed shaft movement states before and after the reversal, and multiplies a lost motion compensation amount computed from the acceleration of the feed shaft after the speed reversal by the factor to compute an actual lost motion compensation amount. With the calculated actual lost motion compensation amount, a feed shaft control part provides actual lost motion compensation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a numerical control device that controls a feed shaft motor that drives a feed shaft in order to suppress a feed shaft tracking error that occurs when a feed shaft is reversed in a feed shaft drive system of a numerical control (NC) machine tool.

  In recent years, with the increase in cutting feed speed of NC machine tools, problems due to non-linear elements in the drive system have become prominent. There is a problem that a phenomenon called a protrusion occurs. This quadrant protrusion has a shape error due to a delay in the actual speed because the output torque of the feed shaft motor cannot respond quickly when the feed shaft reverses at the arc quadrant switching part. This is what happens.

  Conventionally, in order to solve the problems caused by such reversal of the feed axis, various compensation controls are performed at the time of reversing the feed axis. For example, if the feed axis movement command or speed command is monitored and the sign of the feed axis movement direction or speed command value is reversed, the feed axis is reversed by adding and compensating for a constant torque command value in the reversed axis movement direction. There is a method for compensating the starting torque at the time.

  However, according to such a compensation control method, compensation control is performed with a constant torque command value without considering the influence of the sliding resistance that varies depending on the feed shaft speed, so that the change in feed speed when the feed shaft is reversed is changed. Depending on the degree (acceleration), the compensation control may be overcompensated or insufficiently compensated, and a sufficient compensation effect could not be obtained depending on the machining conditions.

  Therefore, in order to solve such a problem, compensation control has been devised in consideration of the degree of change in feed speed when the feed axis is reversed. This compensation control will be described with reference to FIG.

  First, the program analysis unit 1 analyzes the input machining program (NC program). The interpolation calculation unit 2 performs an interpolation calculation based on the analysis result obtained by the program analysis unit 1, generates a movement command Pc for each feed axis, and outputs this movement command Pc to the position control unit 8.

  The position control unit 8 calculates the speed command Vc based on the difference between the position command value in the movement command Pc and the value indicating the actual position of the feed axis in the position feedback signal Pa, and outputs it to the speed control unit 9. . Here, the position feedback signal Pa is a feedback signal for controlling the actual position of the feed shaft in accordance with the command value, and is a signal output from the position detector 12 coupled to the feed shaft motor. is there. The speed command Vc output from the position control unit 8 is corrected for speed by a lost motion correction calculation unit 71 as described later, and the corrected command is input to the speed control unit 9.

  The speed control unit 9 calculates the torque command Tc based on the difference between the speed command value in the speed command subjected to the lost motion correction and the value indicating the actual feed speed in the speed feedback signal Va, toward the power amplification unit 10. Output. Here, the speed feedback signal Va is a feedback signal for controlling the actual feed speed according to the command value, and the position feedback signal Pa from the position detector 12 is the speed detector (differentiator) 13. Is a signal obtained by processing. The torque command Tc output from the speed control unit 9 is subjected to torque correction by the lost motion correction calculation unit 71 in the same manner as the speed command Vc, and the corrected command is input to the power amplification unit 10.

  The power amplifying unit 10 calculates a current value based on the difference between the torque command value in the torque command corrected for lost motion and the value of the feedback signal from the power amplifying unit 10, and outputs the current value to the feed shaft drive motor 11. Thus, the drive control of the feed shaft drive motor 11 is performed by the current output from the power amplifying unit 10.

  Next, the lost motion correction of the speed command Vc and the torque command Tc performed by the lost motion correction calculation unit 71 will be described.

  In the numerical control device of FIG. 3, the speed inversion detection unit 5 monitors the movement command Pc (particularly, the movement state of the feed axis, the feed speed, etc.) from the interpolation calculation unit 2, and determines the movement direction of the feed axis. The acceleration of the feed axis at the time of reversal or reversal is detected. Further, the lost motion correction data storage unit 6 stores in advance data of a lost motion correction amount required according to the acceleration at the time of reversing the feed axis, for example, as shown in FIG. As a method of obtaining this correction amount, for example, an NC machine tool is operated while changing the feed speed condition by a predetermined circular interpolation, the feed axis followability of the arc quadrant switching portion is confirmed for each feed speed, and the feed axis There is a method of obtaining a correction amount required for each acceleration at the time of inversion.

When the speed reversal detection unit 5 detects reversal of the moving direction of the feed axis, the lost motion correction calculation unit 71 acquires the acceleration ΔV at the time of feed axis reversal from the speed reversal detection unit 5,
Thereafter, the lost motion correction amount corresponding to the acceleration ΔV is read from the lost motion correction data storage unit 6, and the speed and torque correction values are calculated and output based on the read lost motion correction amount. The correction value output in this way is added to the command values of the input commands of the speed controller 9 and the power amplifier 10, and the lost motion correction of the speed command Vc and the torque command Tc is performed.

Here, the calculation of the lost motion correction amount in the lost motion correction calculation unit 71 is performed by using a data as shown in FIG. 4 and extracting a correction amount corresponding to the detected acceleration. Therefore, when the speed pattern of the feed speed of the feed shaft is, for example, three speed patterns V1, V2, and V3 shown in FIG. 5, correction amounts ε1, ε2 corresponding to the accelerations ΔV1, ΔV2, ΔV3
, Ε3 is calculated as the lost motion correction amount. Note that the acceleration ΔV in FIG. 5 is positive in the direction opposite to the moving direction of the feed axis (that is, acceleration that decelerates the feed speed), and accelerated in the moving direction of the feed axis (that is, accelerates the feed speed). Acceleration) to be negative. If the acceleration at the time of reversing the feed axis is ΔV1, ΔV2, ΔV3, the lost motion correction is performed with the calculated correction amounts ε1, ε2, ε3 as shown in FIG. Here, the correction amount ε in FIG. 6 is a negative correction amount to be added to the moving direction (speed direction) of the feed shaft after reversal. Accordingly, FIG. 6 shows that lost motion correction is performed such that the correction amounts ε1, ε2, and ε3 are added to the moving direction of the feed axis after reversal. Further, as shown in FIG. 6, the lost motion correction is started from the time of reversing the feed axis, and is controlled to be completed at the time Ta _{a + n} regardless of the magnitude of the acceleration.

Japanese Patent Laid-Open No. 9-319418

According to the above prior art, when performing drive control of the feed axis, the lost motion correction amount and the correction values of the speed and torque are calculated according to the acceleration of the feed axis when the feed axis is reversed. As shown in FIG. 6, when the feed shaft speed change from the feed axis reversal _Ta to the lost motion correction completion _{Ta + n} is constant, the feed shaft follow-up error during feed shaft reversal is suppressed appropriately. Compensation control can be performed.

However, the degree of change in velocity of the feed shaft (acceleration) are the same in the feed shaft when reversing T _a, the movement state change of the feed axis between the feed shaft when reversing T _a time until T _{a + n} lost motion correction completion and, (a different state velocity change during the feed axis inversion) the speed change is not constant in the case, the correction amount corresponding to the acceleration of the feed shaft when reversing T _a, of the feed axis before the lost motion correction completion It was not possible to perform a correction that sufficiently responded to changes in the moving state. As a result, speed / torque compensation control by lost motion compensation is overcompensated or undercompensated, and it is not possible to sufficiently suppress the occurrence of follow-up errors due to jumping or follow-up delay when the feed axis is reversed. However, it was an impediment to improvement of shape accuracy.

  The object of the present invention is to provide a correction value sufficiently corresponding to a change in the feed axis moving state when the feed axis is reversed and the lost motion correction is completed and the change in the feed axis speed is not constant. An object of the present invention is to provide a numerical control device capable of performing lost motion correction.

  The present invention provides a feed axis control unit that outputs a drive control command based on a feed axis movement command of a machine tool and performs drive control of the feed axis, and a lost motion that corrects the drive control command for lost motion when the feed axis is reversed. Including a motion correction unit, wherein the lost motion correction unit performs a movement command before being input to the feed axis control unit. Detecting means for detecting the feed axis inversion and reversal of the feed axis, and the lost motion correction amount used when the feed axis acceleration at the inversion continues during the lost motion compensation for each acceleration. Based on the detected acceleration and the first feed axis after reversal when the acceleration continues during the lost motion correction based on the detected acceleration Based on a predetermined number of movement commands scheduled to be input to the feed axis controller after reversal, a second feed axis movement amount after reversal by the movement command is calculated, A correction for calculating an actual lost motion correction amount used for actual lost motion correction using the first and second feed axis movement amounts and the correction amount acquired from the correction amount data storage means based on the detected acceleration. The feed axis control unit, while performing the lost motion correction at the time of reversal based on the input movement command and the actual lost motion correction amount calculated by the correction amount calculating means. The drive shaft drive control is performed.

  Further, the correction amount calculating means calculates the first feed axis movement amount before reversal when the detected acceleration continues before reversal, and has been input to the feed axis control unit before reversal. Based on a predetermined number of movement commands, a second feed axis movement amount before reversal by the movement command is calculated, and the first and second reversal movement amounts before reversal and the first reversal movement amount after reversal. The actual lost motion correction amount is calculated using the second feed movement amount and the correction amount acquired from the correction amount data storage unit based on the detected acceleration.

  According to the numerical control device of the present invention, in order to feedforward compensate the speed command and the torque command with appropriate values according to the speed change degree (acceleration) when the feed axis is reversed and the feed axis movement state after the feed axis is reversed. Even when the feed axis movement state after feed axis reversal changes before the lost motion correction is completed, it is possible to suppress the state of speed compensation and torque compensation over-compensation or under-compensation in lost motion compensation and improve shape accuracy. it can.

  A numerical control apparatus according to an embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is shown in FIG. 1 about the part equivalent to the prior art shown in FIG.

  In the numerical control device of the present embodiment, the program analysis unit 1 analyzes the input machining program (NC program), and the interpolation calculation unit 2 performs an interpolation calculation based on the analysis result obtained by the program analysis unit 1. . Here, the movement command as the interpolation calculation result output from the interpolation calculation unit 2 is stored in the first storage unit 31 by the first interpolation storage control unit 3 every time it is output.

  The first storage unit 31 can sequentially update and store movement commands for a predetermined number of times n before being input to the position control unit 8. Here, when the first storage unit 31 has already stored the movement command for the predetermined number of times n and the latest movement command is output from the interpolation calculation unit 2, the first interpolation storage control unit 3 Of the movement commands stored in the storage unit 31, the oldest movement command that has passed a predetermined number of times n is output to the second interpolation storage control unit 4 and the position control unit 8, and the latest movement command from the interpolation calculation unit 2 is output. The movement command is updated and stored in the first storage unit 31.

  The second storage unit 41 can sequentially update and store the movement command for the predetermined number of times n output from the first storage unit 31. Here, when the second storage unit 41 has already stored the movement command for the predetermined number of times n and the movement command is output from the first storage unit 31, the second interpolation storage control unit 4 41, delete the oldest movement command that has passed n times a predetermined number of times, and update and store the movement command transferred from the first interpolation storage control unit 3 in the second storage unit 41. Let

  When the movement command output from the first storage unit 31 by the first interpolation storage control unit 3 is input to the position control unit 8, the lost motion correction (speed command and torque) by the lost motion correction calculation unit 7 is performed as in the conventional case. Command feedforward compensation) and feedback control from the position detector 12 are performed, and drive control of the feed shaft drive motor 11 is performed via the position control unit 8, the speed control unit 9, and the power amplification unit 10.

  Next, the lost motion correction of the speed command Vc and the torque command Tc performed by the lost motion correction calculation unit 7 in the numerical control device of the present embodiment will be described.

  The speed reversal detection unit 5 monitors the movement command Pc output from the first storage unit 31 (particularly, the movement state of the feed axis, the feed speed, etc.), and reverses or reverses the feed axis movement direction. The acceleration of the feed axis is detected. Further, the lost motion correction data storage unit 6 stores in advance data of a lost motion correction amount required according to the acceleration at the time of reversing the feed axis, as shown in FIG. . In this embodiment, the reversal of the moving direction of the feed axis is detected by detecting the reversal of the sign of the speed, but the reversal detection method of the moving direction is not limited to this.

When the speed reversal detection unit 5 detects the reversal of the moving direction of the feed axis, the lost motion correction calculation unit 7 acquires the acceleration ΔV at the time of feed axis reversal from the speed reversal detection unit 5, and thereafter, this acceleration ΔV The lost motion correction amount corresponding to is read from the lost motion correction data storage unit 6. The lost motion correction calculation unit 7 also moves the feed axis before and after feed axis reversal, as will be described later, based on the movement commands stored in the first storage unit 31 and the second storage unit 41 when feed axis reversal is detected. And a coefficient value to be described later is calculated using the obtained value. Then, the actual lost motion correction amount is calculated by multiplying the coefficient value by the lost motion correction amount read from the lost motion correction data storage unit 6, and the speed and torque are corrected based on the actual lost motion correction amount. The value is calculated and the correction value is output. The correction value output in this way is added to the command values of the input commands of the speed controller 9 and the power amplifier 10, and the lost motion correction of the speed command Vc and the torque command Tc is performed.

  Here, the calculation rule of the actual lost motion correction amount by the lost motion correction calculation unit 7 will be described below.

  The lost motion correction calculation unit 7 calculates the total amount Σ1 of the movement amounts stored in the first storage unit 31. Since the movement command as the interpolation result stored in the first storage unit 31 indicates the position of each interpolation time point that has not yet been output to the position control unit 8, the first storage unit 31 performs the feed axis inversion. The axis movement position data after the time of occurrence is stored for a predetermined number of times n. Accordingly, by calculating the difference between the feed axis position indicated in the newest interpolation result stored in the first storage unit 31 and the feed axis position at the time of feed axis inversion, the feed axis inversion is calculated. It is possible to calculate the total amount Σ1 of the movement amounts by the movement command for n times after that.

  In addition, the lost motion correction calculation unit 7 also calculates the total amount Σ2 of the movement amounts stored in the second storage unit 41. Since the movement command as the interpolation result stored in the second storage unit 41 indicates the position of each interpolation point already output to the position control unit 8, the second storage unit 41 generates feed axis inversion. The axis movement position data before the operation is stored n times a predetermined number of times. Accordingly, by calculating the difference between the feed axis position at the time of feed axis reversal and the feed axis position indicated by the oldest interpolation result among the interpolation results stored in the second storage unit 41, the feed axis reverse It is possible to calculate the total amount Σ2 of the movement amount based on the movement command for the previous predetermined number of times n.

Further, the lost motion correction amount that is a reference for the correction amount of the lost motion correction at the time of reversing the feed axis is obtained from the acceleration ΔV detected when the feed axis is reversed as shown in FIG. This lost motion correction amount is an optimal correction amount when the acceleration ΔV before and after reversing the feed axis continues until the lost motion correction is completed (corresponding to the time Ta _{a + n in} FIG. 6). Then, when the acceleration ΔV before and after the axis reversal of the feed axis continues until the completion of the lost motion correction, the feed axis movement amount by the movement command for the predetermined number n times before the feed axis inversion and the predetermined number n times after the feed axis inversion. The total Σ3 with the feed axis movement amount by the movement command is calculated by Σ3 = 1/2 × ΔV × n × n × 2 = n ² × ΔV.

  The lost motion correction calculation unit 7 calculates a coefficient K = (Σ1 + Σ2) / Σ3 using the feed axis movement amounts Σ1, Σ2, and Σ3 calculated in this way.

  Then, the calculated coefficient K is multiplied by the lost motion correction amount read from the lost motion correction data storage unit 6 to calculate the actual lost motion correction amount. Based on the actual lost motion correction amount calculated in this way, the speed and torque correction values are calculated and output, and the correction values are added to the command values of the input commands of the speed control unit 9 and the power amplification unit 10. The lost motion correction of the speed command Vc and the torque command Tc is performed.

For example, if the feed shaft is moved it indicates the moving state of the cross feed axis reversed as in FIG. 2, lost motion correction calculation unit 7 first, the lost motion correction amount corresponding to the acceleration ΔV1 in the feed shaft when reversing T _a .epsilon.1 Is read from the lost motion correction data storage unit 6. Next, based on the predetermined n times of movement commands stored in the first storage unit 31, the movement amount Σ1 of the feed shaft after the feed shaft is reversed is calculated. Further, based on a predetermined n times of movement commands stored in the second storage unit 41, the movement amount Σ2 of the feed shaft before the feed shaft is reversed is calculated.

In addition, the lost motion correction calculation unit 7 determines that the feed axis movement amount and the feed axis reversal for a predetermined number of times n before the feed axis inversion when the acceleration ΔV1 before and after the axis inversion of the feed axis continues until the completion of the lost motion correction. The sum Σ3 with the feed axis movement amount for the subsequent predetermined number n is calculated as described above. Then, the coefficient K is calculated as described above using the calculated movement amounts Σ1, Σ2, and Σ3, and the lost motion correction amount ε1 read from the lost motion correction data storage unit 6 is multiplied by the coefficient K to obtain the actual lost. A motion correction amount εr is obtained.

Thus, lost motion correction amount used in the lost motion correction of the velocity command Vc and the torque command Tc is the moving state after feed axis inversion (the amount of movement of the feed shaft), the acceleration ΔV1 of the feed axis inversion time T _a The corresponding lost motion correction amount ε1 is suppressed to the actual lost motion correction amount εr. Then, speed and torque correction values are calculated based on the actual lost motion correction amount εr, and the correction values are added to the command values of the input commands of the speed control unit 9 and the power amplification unit 10, respectively. Lost motion correction of the speed command Vc and the torque command Tc based on the lost motion correction amount εr is performed.

  As described above, according to the numerical control device of this embodiment, when the feed axis movement state after the feed axis inversion changes before the lost motion correction is completed, the lost motion is changed according to the change in the movement state. The correction amount is suppressed. Therefore, it is possible to suppress the state such as over-compensation or under-compensation of the speed and torque compensation that has occurred in the conventional apparatus in the same case, and the shape accuracy can be improved.

As shown in the speed pattern V1 in FIG. 6, the feed axis movement state after the feed axis is reversed does not change before the lost motion correction is completed, and a constant speed change continues before and after the feed axis is reversed, and the lost motion correction is performed. In the case of continuing until completion, the coefficient K = 1 is calculated. Thus, the real lost motion correction amount εr of this case, after all, the lost motion correction amount ε1 in response to the acceleration ΔV1 in the feed shaft when reversing T _a. In this way, when the feed axis movement state after the feed axis inversion does not change before the lost motion correction is completed and a constant speed change continues, based on the lost motion correction amount ε1, as in the conventional case. Speed and torque correction values are calculated, and the lost motion correction of the speed command Vc and the torque command Tc is performed between the feed axis reversal time _Ta and the time _{Ta + n based on the} correction value.

  In this case, the feed axis movement amounts Σ1, Σ2 before and after the feed axis inversion and the predetermined number n before and after the axis inversion of the feed axis when the acceleration before and after the feed axis inversion continues until the completion of the lost motion correction. Although the coefficient K is calculated by using the feed axis movement amount Σ3 for each batch, the present invention is not limited to this. For example, the feed axis movement amount Σ11 after reversing the feed axis and the feed axis movement amount Σ31 for a predetermined number of times after the feed axis reversal when the acceleration before and after the reversal of the feed axis continues until the lost motion correction is completed are used. Thus, the coefficient K1 (= Σ11 / Σ31) may be calculated. Then, the actual lost motion correction amount is obtained in the same manner as described above using the obtained coefficient K1, and the speed command Vc and the torque command Tc are calculated based on the speed and torque correction values obtained based on the actual lost motion correction amount. Even if the lost motion correction is performed, the same effect can be obtained. In this case, the second storage control unit 4 and the second storage unit 41 are unnecessary in the numerical control device.

It is a figure which shows the structure of the numerical control apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the lost motion correction amount at the time of the feed axis inversion calculated by the numerical control apparatus of this invention. It is a figure which shows the structure of the conventional numerical control apparatus. It is a figure which shows the relationship of the lost motion correction amount required according to the acceleration at the time of feed axis inversion memorize | stored in a lost motion correction data memory | storage part. It is a figure which shows the relationship of the acceleration at the time of feed axis reversal. It is a figure which shows the lost motion correction amount at the time of the feed axis inversion calculated by the conventional numerical control apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Program analysis part, 2 interpolation calculating part, 3 1st interpolation memory | storage control part, 31 1st memory | storage part, 4 2nd interpolation memory | storage control part, 41 2nd memory | storage part, 5 speed inversion detection part, 6 Lost motion correction data memory | storage Unit, 7 lost motion correction calculation unit, 8 position control unit, 9 speed control unit, 10 power amplification unit, 11 feed shaft drive motor, 12 position detector, 13 speed detection unit.

Claims (4)

A feed axis control unit that outputs a drive control command based on a movement command of a feed axis of a machine tool and performs drive control of the feed axis; a lost motion correction unit that corrects the drive control command for lost motion when the feed axis is reversed; In the numerical control device that performs drive control of the feed axis while correcting the lost motion when the feed axis is reversed,
The lost motion correction unit
Detecting means for monitoring a movement command before being input to the feed axis control unit, and detecting the acceleration of the feed axis when the feed axis is reversed and reversed;
Correction data storage means for storing, for each acceleration, a lost motion correction amount used when the acceleration of the feed axis at the time of inversion during the lost motion correction continues;
Based on the detected acceleration, the first feed axis movement amount after reversal is calculated when the acceleration continues during the lost motion correction, and the predetermined number of times that is scheduled to be input to the feed axis control unit after reversal. Based on the movement command, the second feed axis movement amount after reversal by the movement command is calculated, and the correction amount data storage is performed based on the first and second feed axis movement amounts after the reversal and the detected acceleration. Correction amount calculation means for calculating an actual lost motion correction amount used for actual lost motion correction using the correction amount acquired from the means;
Including
The feed axis control unit performs drive axis drive control while performing lost motion correction at the time of reversal based on the input movement command and the actual lost motion correction amount calculated by the correction amount calculating means. A numerical controller characterized by the above. The numerical control apparatus according to claim 1,
The correction amount calculating means includes
When the detected acceleration continues before reversal, the first feed axis movement amount before reversal is calculated, and based on a predetermined number of movement commands already input to the feed axis control unit before reversal. , Calculating a second feed axis movement amount before reversal by the movement command, first and second reversal movement amounts before reversal, and first and second feed movement amounts after reversal, A numerical control device, wherein an actual lost motion correction amount is calculated using a correction amount acquired from the correction amount data storage unit based on the detected acceleration. A feed axis control unit that outputs a drive control command based on a movement command of a feed axis of a machine tool and performs drive control of the feed axis; a lost motion correction unit that corrects the drive control command for lost motion when the feed axis is reversed In the numerical control device that performs drive control of the feed axis while correcting the lost motion when the feed axis is reversed,
A pre-input command storage means capable of storing a movement command before being input to the feed axis control unit for a predetermined number of times;
Pre-input command storage control means for sequentially storing the movement command in the pre-input command storage means, and is input when the latest movement command is updated and stored in the pre-input command storage means having stored the movement command for a predetermined number of times. Pre-input command storage control means for outputting the oldest movement command in the previous command storage means from the pre-input command storage means;
Detecting means for monitoring the movement command output from the pre-input command storage means and detecting the acceleration of the feed axis when the feed axis is reversed, and
Correction data storage means for storing, for each acceleration, a lost motion correction amount used when the acceleration of the feed axis at the time of reversal during the lost motion correction continues;
Based on the detected acceleration, the first feed axis movement amount after reversal when the acceleration continues during lost motion correction is calculated, and the movement command stored in the pre-input command storage unit at the time of reversal detection is calculated. Based on the first and second feed axis movement amount after the reverse and the detected acceleration, the second feed axis movement amount after the reverse control that is actually controlled is calculated and acquired from the correction amount data storage means. Correction amount calculating means for calculating an actual lost motion correction amount used for actual lost motion correction using the corrected amount,
Including
The feed axis control unit feeds the feed axis while performing lost motion correction during reversal based on the movement command output from the pre-input command storage means and the actual lost motion correction amount calculated by the correction amount calculation means. A numerical control apparatus characterized by performing drive control. In the numerical control device according to claim 3,
Post-input command storage means capable of updating and storing the movement command output from the pre-input command storage means;
Post-input command storage control means for sequentially storing the movement command output from the pre-input command storage means in the post-input command storage means;
Further comprising
The correction amount calculating means includes
Based on the detected acceleration, the first feed axis movement amount before reversal when the acceleration continues during lost motion correction is calculated, and the movement command stored in the command storage unit after input at the time of reversal detection is calculated. Based on the actually controlled second feed axis movement amount before reversal, the first and second feed shaft movement amounts before reversal and the first and second feed shaft movement amounts after reversal are calculated. And calculating the actual lost motion correction amount using the correction amount obtained from the correction amount data storage means based on the detected acceleration.

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