KR100467015B1 - Servo controller and method - Google Patents

Abstract

The ideal position is calculated according to the ideal servo system model, and the difference between the calculated abnormal position and the actual position feedback is multiplied by a predetermined gain only a predetermined time from the time of reversal of the abnormal position, and the speed command is used as a correction amount. By suppressing the disturbance of the correction effect due to the aging effect of the friction amount and the difference in the machining conditions, and suppressing the distortion caused by the torsion recovery after correction even in a large mechanical system where the elasticity of the ball screw torsion or the actual change is large. At the same time, the servo system is prevented from becoming unstable.

Description

Servo control method and device thereof {SERVO CONTROLLER AND METHOD}

In CNC machine tools, a servomotor rotates a driving ball screw to move a table for fixing a work. Therefore, in the case of circular cutting, for example, a ball screw ball machine or a machine is well known. The direction of movement of the table does not change immediately due to the friction of each part, and there is a problem that projections called upper limit synchronous are generated on the cutting surface of the workpiece near the upper limit boundary, resulting in a decrease in machining accuracy.

9 shows a block diagram of a conventional servo control device intended to prevent the occurrence of such an upper limit projection. In Fig. 9, 1 is a position command generation unit, 2 is a position control unit, 3 is a speed controller, 4 is a current controller, 5 is a power amplifier, 6 is a servo motor for driving the mechanical system 16, 7 is a servo motor (6). The encoder for detecting the rotational position of the reference signal 8, and the derivative means for calculating the speed by differentiating the position detection signal 10 output from the encoder (7). In addition, the encoder 7 and the derivative means 8 constitute a motor speed detecting means. 9 is a position command output from the position command generation unit 1, 10 is a position feedback signal which is a position detection signal output from the encoder 7, 11 is a speed command output from the position control unit 2, 12 is a derivative means 8 The speed feedback signal 13, which is a speed detection signal output from the speed feedback signal, 13 is a speed deviation signal that is a difference between the speed command 11 and the speed feedback 12, 14 is a current command output from the speed controller 3, and 15 is a servo motor. Current feedback signal for indicating the current flowing in (6), 16 is a mechanical system such as a CNC machine tool driven by the servo motor (6), 17 is a reaction force applied to the servo motor (6) from the mechanical system (16) Load torque due to frictional force, 18 is a speed proportional control unit in the speed control unit 3, 19 is a speed integral control unit in the speed control unit 3, 20 is a proportional proportional command output from the speed proportional control unit 18, 21 is a speed As an integral term command output by the integral controller 19, it is added to the proportional term command 20 so that the current command 1 4) becomes.

Further, 22 denotes a correction signal generation unit which suppresses an error in the command position generated during the direction change of the servomotor 6 or the machine under the influence of friction, and prevents the occurrence of the upper limit projection in the case of circular arc cutting. 23 is a current command correction signal (correction value) output from the correction signal generation section 22.

In the conventional apparatus, the correction amount 23 corresponding to the friction amount is applied at the time of reversing the direction of the servomotor 6, and the correction amount is set in advance as a parameter or according to the conditions of the feed rate and acceleration stored in the memory. Optimal value is used. In some cases, the amount of correction was added as a function of time or as a function of the amount of movement or the feed rate.

By the way, such a conventional servo control apparatus needs to determine the optimum value under predetermined conditions at the time of machine adjustment as the correction amount, but the friction amount, which is an error factor in this direction reversal, is a condition such as secular variation or machine position. The change due to the difference was large, and it was difficult to determine the optimal correction amount.

Moreover, even if the correction amount was determined, for example, as time passed, there was a problem that an optimum effect was hardly obtained.

In a mechanical system with large elastic changes such as torsion of the ball screw and actual material (sliding is freely installed around the axis of the servomotor so that oil does not enter the servomotor side, the outer peripheral part is fixed to the base). The error due to the tracking delay (upper limit projection) occurring at the time of reversal of the direction is corrected, but it is not possible to suppress digging due to subsequent screw turning.

10A and 10B are simulations of the behavior at the time of inversion of direction before correction in a mechanical system in which a large change in elasticity such as torsion or reality is caused in the ball screw, and FIG. Is displayed. In such a mechanical system, the result of the conventional correction shown in FIG. 9 is FIG.

Fig. 11A shows the true precision and Fig. 11B shows the speed and current waveform at the time of reversal.

In the conventional correction, the correction value corresponding to the friction amount is applied during the inversion of the direction such as gradually increasing the correction amount according to the distance in the direction reversal, but when applied to a system having elasticity such as torsion of the mechanical system, As described above, the correction value may be overcorrected momentarily, and even before that, since there is no means for changing the correction value, digging occurs.

Another conventional servo controller is shown in FIG. 12.

12 is an invention disclosed in Japanese Patent Laid-Open No. 1-276315. In the drawing, Xc is a position command, 101 is a position command Xc and the output signal X of the position detector 105 is compared and subtracted. A subtractor for outputting the deviation E, 102 an amplifier for amplifying the deviation E and outputting a speed command, 103 a speed controller for controlling the drive output to the servomotor 104 in accordance with the input speed command V, and The machining machine 106 performs, for example, movement of a machining tool or movement of a machining table on which a workpiece is placed by driving the servomotor 104, and 106 detects the position of the moving body in the machining machine 105. The position detector 107 is an abnormal position calculator.

The abnormal position calculator 107 further includes a subtractor 108 for outputting a deviation Ei between the position command Xc and the abnormal position Xi, an amplifier 109 for amplifying the deviation Ei and outputting a speed signal Vi, and a speed signal Vi (speed). And an integrator 116 that outputs the abnormal position signal Xi corresponding to the abnormal position by time-integrating the command).

111 is a subtractor which outputs a deviation between the deviation Ei and the deviation E, 112 is an amplifier which supplies a correction gain to the deviation output by the subtractor 111, and 113 is an adder which adds a deviation obtained by multiplying the speed command V by the correction gain.

The servo control device is configured to reduce the speed command V when the position detected by the position detector 106 is earlier than the abnormal position and to increase the speed command V when the position is delayed. The error multiplied by the gain is added to the speed command V.

12 is not limited to the direction reversal, and the error is always amplified and corrected to correct the error between the abnormal position and the actual position. There existed a problem that the error by tracking delay which arises at the time of reversal cannot be suppressed enough. 13A, 13B and 13C show corrections in the invention disclosed in Japanese Laid-Open Patent Publication No. 1-276315 on a mechanical system having a large change in elasticity such as torsion or reality to the ball screw shown in FIGS. 11A and 11B. It simulates the behavior of. In FIG. 13A, FIG. 13A, FIG. 13A shows the roundness precision, and FIG. 13B shows the speed and current waveform at the time of reversal of direction, and it is easy to induce mechanical vibration, and the position, speed, and current waveform are vibrated. The presence of spinous processes in epicenter precision remains relatively large.

(Initiation of invention)

The present invention is intended to solve the above problems, and suppresses the disturbance of the correction effect due to the aging effect of the friction amount and the difference in the processing conditions, and also the mechanical system with a large elastic change such as the torsion of the ball screw or the actual material. In addition, it is possible to provide a servo control method and apparatus capable of suppressing disturbance due to torsional recovery after correction and preventing the servo system from becoming unstable by the correction.

Thus, the servo control method according to the present invention generates a speed command according to the difference between the position command and the actual position feedback, and generates a current command according to the difference between the speed command and the actual speed feedback. In the servo control method that controls the servomotor according to the current command, the ideal position is calculated according to the ideal servo system model, and the difference between the calculated abnormal position and the actual position feedback from the reverse direction of the abnormal position is calculated. Only a predetermined time is multiplied by a predetermined gain and added as a correction amount to the speed command.

In the servo control method according to the present invention, the gain is attenuated at a predetermined time with the maximum value at the time of inversion of the abnormal position.

In addition, the servo control method according to the present invention stores the difference between the abnormal position and the actual position feedback at the time of reversal of the abnormal position as an offset value, at the same time as the offset value, and subtracts the difference by this offset value. This subtraction is multiplied by the gain.

The servo control method according to the present invention generates a speed command according to the difference between the position command and the actual position feedback, and generates a current command according to the difference between the speed command and the actual speed feedback. In the servo control method for controlling the servomotor according to this current command, the ideal position is calculated according to the ideal servo system model, and the position feedback or the ideal servo system is only for a predetermined time from the direction reversal of the calculated abnormal position. The accumulated position of the model is multiplied by a predetermined gain and added to the current command as a correction amount.

In the servo control method according to the present invention, the speed feedback or the speed of the ideal servo system model is multiplied by a predetermined gain only for a predetermined time from the time of reversing the direction of the abnormal position, and is applied to the current command as a correction amount.

The servo control method according to the present invention uses coefficients proportional to the difference between the abnormal position and the actual feedback position.

In addition, the servo control apparatus according to the present invention includes means for detecting the position and speed of the servo motor, a position control unit for generating a speed command in accordance with the difference between the position command and the actual position feedback, and the speed command and the actual command. An ideal servo system in a servo control device for controlling the servo motor, comprising a speed control part for generating a current command according to a difference from the speed feedback, and a current control part for controlling a current flowing to the servo motor according to the current command. The model and the model are configured to include a means for multiplying the accumulated position of the servo system model by a gain for a predetermined time from the time of reversing the direction of the abnormal position, and applying this as a correction amount to the current command.

Moreover, the servo control apparatus which concerns on this invention is provided with the means which adds as a correction amount to the said speed feedback or an ideal electric current command for a predetermined time from the direction discharge of the abnormal position of the said model.

The servo control device according to the present invention is configured to use a coefficient proportional to the difference between the abnormal position and the actual feedback position.

The servo control method and apparatus thereof according to the present invention have the ideal servo system model in consideration of the delay of the position loop system from the position command to the position feedback and the mechanical delay of the control object.

The present invention relates to a method and apparatus for controlling a servo motor for driving a CNC machine tool or the like.

1 is a block diagram showing a servo control device according to Embodiment 1 of the present invention.

2A, 2B and 2C show simulation results when the servo control device according to Embodiment 1 of the present invention is applied to a large mechanical system of elastic change.

Fig. 3 is a block diagram showing the servo control device according to Embodiment 2 of the present invention.

4A and 4B show simulation results when the servo control device according to Embodiment 2 of the present invention is applied to a mechanical system having a large change in elasticity.

Fig. 5 is a block diagram showing the servo control device according to Embodiment 3 of the present invention.

Fig. 6 is a block diagram showing a servo control device according to Embodiment 4 of the present invention.

Fig. 7 is a block diagram showing the servo control device according to Embodiment 5 of the present invention.

Fig. 8 is a block diagram showing the servo control device according to Embodiment 6 of the present invention.

9 is a block diagram showing a conventional servo control device.

10A and 10B show simulation results when no correction is used in a mechanical system with large elastic change.

11A and 11B show simulation results when the conventional servo controller is applied to a mechanical system with large change in ballistics.

12 is a block diagram showing another conventional servo control device.

13A, 13B and 13C show simulation results when another conventional servo control device is applied to a mechanical system having a large change in elasticity.

(The best form to carry out invention)

Embodiment 1.

1 is a block diagram of a servo control device according to Embodiment 1 of the present invention.

In the figure, 24 is an abnormal model of the position loop system for inputting the position command 9 output from the position command generation unit 1, 33 is an output speed signal of the abnormal model 24 of the position loop system, and 25 is an elastic change. The ideal model taking into consideration the delay of the large mechanical system, 41 is a subtractor which outputs the difference 27 between the position 26 of the abnormal model and the actual position feedback 10, and 28 is a gain. As the gain 28 is set larger, the correction effect may be desired. However, in order to actually increase the correction effect, the response of the speed loop control system including the mechanical system is required. In case of application to actual machine, it is decided by speed loop control.

Further, 42 multiplies the gain 28 by the difference 27 between the position 16 of the abnormal model and the actual position feedback 10, and outputs a speed command correction signal (speed command correction value) 29. The multiplier 43 is an adder that adds a correction signal (speed command correction value) 29 output from the multiplier 36 to the speed command 11.

In addition, the same code | symbol as the code | symbol shown in FIG. 8 is the same as that shown in FIG.

The servo control apparatus according to Embodiment 1 of the present invention is configured as described above, and the direction inversion of the abnormal model is regarded as the timing of correction, and from this direction inversion until the current command reaches a value exceeding the static friction. Not only a predetermined time (this predetermined time is parameterized in advance) or more than a value obtained by multiplying the movement amount of the abnormal model after reversing the direction by the spring constant of the mechanical system, etc. (this value also sets the parameter in advance) In the multiplication section 42, the speed command correction value 29 is multiplied by multiplying the gain 28 by the difference 27 between the position 26 of the abnormal model and the actual position feedback 10. ) Is added and the correction value 29 is added by the adder 43 to the speed command 11 which is an output by position control.

2A, 2B, and C are simulation results showing the effect of performing the correction of this embodiment on a mechanical system having a large change in elasticity, and the correction amount is determined according to the error occurring at each instant. The same incidence that occurred at the time of a conventional calibration is also suppressed, and it is stable and does not cause mechanical vibration even when compared with the result of the calibration in the invention of the numerical control device disclosed in Japanese Patent Laid-Open No. 1-276315. It can be seen that a highly accurate correction effect is obtained.

Embodiment 2.

3 is a block diagram of a servo control device according to Embodiment 2 of the present invention.

In Embodiment 2, in the first embodiment, the multiplication unit 42 multiplies the difference 27 between the position 26 of the abnormal model and the actual position feedback 10 after the direction reversal at the time of direction reversal. Attenuation as a function of time as a maximum value or as a function of anomaly model position (the slope may be constant when the actual operation is simplified, but attenuation such as exponential attenuation is also effective when the local correction in the direction reversal is performed). The gain is changed to 28A.

The other configuration is the same as that of the first embodiment.

The servo control apparatus according to Embodiment 2 of the present invention is configured as described above, and the position of the abnormal model and the actual position of the abnormal model are multiplied by the multiplier 42 with the timing of the start of correction being the direction change of the abnormal model. The speed command correction value 29 is multiplied by multiplying the difference 27 with the feedback 10 by a gain 28A (a gain attenuated by a function of time as a maximum value or a function of an abnormal model position at the time of reversal). And the correction value 29 is added by the adder 43 to the speed command 11 which is an output by position control.

4A and 4B show a simulation result showing the effect when the correction of the present embodiment is performed, and the weight due to the gain of the correction amount can be intensively increased at the time of reversing the direction, so that it is difficult to induce mechanical vibration again. It becomes possible to raise the correction effect.

Embodiment 3.

5 is a block diagram of a servo control device according to Embodiment 3 of the present invention.

In the figure, 30 is a storage unit that stores, as the offset value 31, the difference 27 immediately after the direction reversal between the position 26 of the abnormal model and the actual position feedback 10. In addition, the offset value 31 rewrites the upper and lower sides every direction reversal. In addition, 44 is a subtraction part which outputs the difference 27 between the position 26 of the abnormal model after direction reversal, and the actual position feedback 10, and the difference 32 between the offset value 31. As shown in FIG. The other configuration is the same as that of the second embodiment.

The servo control device according to Embodiment 3 of the present invention is configured as described above. First, the difference 27 immediately after the direction reversal between the position 26 of the abnormal model and the actual position feedback 10 is determined. The offset value 31 is stored in the storage unit 30. The subtraction unit 38 subtracts the offset value 31 from the difference 27 after the direction reversal between the position 26 of the abnormal model and the actual position feedback 10. ) Is multiplied by the gain 28A (a gain attenuated by a function of time as a maximum value or a function of an abnormal model position at the time of reversal) in the multiplier 42 to generate a speed command correction value 29, and the correction value ( 29) is added to the speed command 11, which is an output by the position control, in the adder 37. FIG.

This eliminates the error between the abnormal model caused by the modeling error during high speed and high acceleration operation and the position feedback of the actual motor or the mechanical system, and corrects only the error during the upper limit switching, which is stable and stable. Moreover, the suppression effect of an upper limit protrusion can be adjusted high.

Embodiment 4.

6 is a block diagram of a servo control device according to Embodiment 4 of the present invention.

In the figure, 24 denotes an abnormal model of the position loop system, 33 denotes an output speed signal of the abnormal model 24 of the position loop system, and 25 denotes an elasticity, which inputs the position command 9 output from the position command generation unit 1. The abnormal model considering the delay of the large mechanical system, 35 detects the direction reversal by the model speed signal 33 generated from the abnormal model 24 of the position loop system, and when the direction reversal is detected, when the direction reversal is detected. The position feedback value is assumed to be 0. (It is preferable to use the actual position feedback 10. However, if the position feedback resolution is not smooth, the correction amount may be vibrated and may cause resonance of the machine.) In this case, the calculator calculates the position 36 at the direction reversal from the cumulative position of the output position 26 of the abnormal model, and 34 multiplies the value calculated by the calculator 38 to multiply the current. Command correction value 23) is a spring constant that compensates for the torsion caused by elastic deformation such as ball screws or oil seals in mechanical systems.

In addition, the same code | symbol shown in FIG. 9 is the same as that shown in FIG.

The servo control device according to Embodiment 4 of the present invention is configured as described above, and the direction reversal is detected by the model speed signal 33 generated from the abnormal model 24 of the position loop system, and the direction reversal is detected. In this case, the position at the time of reversal is set to 0, the calculator 35 is calculated, and this value is multiplied by a spring constant 34 that compensates for the torsion caused by elastic deformation such as a ball screw or oil seal of a mechanical system. Using the current command correction value 23 until the correction value exceeds the static friction amount, or until the current command of the total to which the correction amount is applied exceeds the static friction amount, the speed proportional integral command 20 or the speed integral integral The instruction 21 is added to the instruction 21.

As a result, the spring torque element such as torsion of the ball screw dissipates the load torque in the large machine, and the compensation is proportional to the cumulative position from the direction reversal. This makes it difficult to produce a phenomenon or the like, and correction of changes in speed, friction, and the like becomes possible.

Embodiment 5.

7 is a block diagram of a servo control device according to Embodiment 5 of the present invention.

In the figure, 37 is a speed feedback value when the direction reversal is detected by the speed signal 33 generated from the model position loop (this is preferably the actual speed feedback 12, but the speed feedback resolution is good). If not, there is a possibility that the correction amount remains residual and may cause resonance of the machine. In such a case, the mechanical system used as the current command correction value 38 by multiplying by the output speed signal 33 of the abnormal model may be used). The viscosity constant which compensates the viscous friction term which arises in the power supply parts, such as a ball screw and an oil seal, 39 is a current command by adding the current command complement 23 and the said current command correction value 38 which were described in Embodiment 4, An adder that outputs a correction value 40.

The other configuration is the same as that of the fourth embodiment.

The servo control device according to Embodiment 5 of the present invention is configured as described above, and the direction reversal is detected by the model speed signal 33 generated from the abnormal model 24 of the position loop system, and the direction reversal is detected. If the position at the time of reversal is set to 0, the position 36 from the position reversal is calculated by the calculator 35 from the position feedback 10 (or the accumulated position of the output position 26 of the abnormal model). The current command correction value 23 is generated by multiplying the spring constant 34 to compensate for the torsion caused by the elastic deformation of the ball screw or oil seal of the mechanical system.

In addition, the direction reversal is detected by the model speed 33 generated from the abnormal model 24 of the position loop system, and the velocity feedback 12 (or the output of the abnormal model is set to 0 when the direction reversal is detected). The current command correction value 38 is generated by multiplying the speed 33) by the viscosity constant 37 for compensating for the viscous friction term generated in the rotating part such as a ball screw or an oil chamber of the mechanical system.

Then, the current command correction value 23 and the current command correction value 38 are added by the adder 39 to the current command correction value 40 until the correction value exceeds the static friction amount or the total current command to which the correction amount is applied. It is added to the speed proportional terminology command 20 or the speed integral terminology command 21 until it exceeds this static friction amount. Thus, the correction by the spring constant of Embodiment 4, which is effective for reversing the direction at low speed, is added. In addition, in order to provide correction by the viscous term which becomes dominant at high speed, it is more stable against the speed change than the fourth embodiment, and high precision correction is possible.

Embodiment 6.

8 is a block diagram of a servo control device according to Embodiment 6 of the present invention.

In the sixth embodiment, the spring constant 34, which is a term for compensating the spring constant, and the viscosity constant 37, for compensating for the viscous term, are provided with the position 26 of the abnormal model and the actual position feedback 10. The gain is proportional to the difference (error) 27 from.

The other configuration is the same as that of the fifth embodiment.

As a result, the spring system elements such as torsion of the ball screw dissipate the load torque in large machines, and the compensation is proportional to the cumulative position from the direction reversal, and the overcompensation is also performed for the mechanical system having spring elements such as elastic deformation. It is not only possible to make a dent into the ground, but it is possible to make stable correction even for changes in speed or friction load, and the spring constant and viscosity constant that determine the correction amount are variable due to the error from the abnormal position. In addition, it is possible to construct a system that can cope with aging changes of spring constants, viscosity constants, and machine conditions.

In the sixth embodiment, only one of the spring constant 34, which is a term for compensating the spring constant, and the viscosity constant 37, for compensating for the viscosity term, is the position 26 of the abnormal model and the actual position feedback 10. It is also possible to set the gain proportional to the difference 27 with.

As described above, according to the present invention, the ideal position is calculated according to the ideal servo system model, and the difference between the calculated abnormal position and the actual position feedback is only a predetermined time from when the direction of the abnormal position is reversed. By multiplying a predetermined gain and applying it as the correction amount to the speed command, it is possible to suppress the disturbance of the correction effect due to the aging effect of the friction amount and the difference in the machining conditions, and also to prevent the elasticity of the ball screw from distortion Even in a mechanical system with a large change, it is possible to suppress the dent due to torsion after correction. In addition, the servo system can be prevented from becoming unstable and stable correction is possible.

According to the present invention, since the gain is used to attenuate at a predetermined time as a maximum value at the time of inversion of the abnormal position, the servo system can be prevented from becoming unstable, and further accurate correction is possible.

According to the present invention, the difference between the abnormal position and the actual position feedback at the time of inversion of the abnormal position and the actual position feedback is stored as an offset value, and the difference is subtracted from this offset value, and the subtracted product is multiplied by the gain. It is possible to eliminate the error between the abnormal model caused by the modeling error during high speed and high acceleration operation and the actual position feedback of the motor or the mechanical system, and correct only the error at the upper limit switching, which is stable, Moreover, the adjustment which makes higher the suppression effect of an upper limit protrusion becomes possible. This is because, as a result of simulating the behavior disclosed in Japanese Unexamined Patent Publication No. 1-276315, the correction of high gain (amplification value) for an error other than the objective may cause vibration or resonance of the machine. It is validated that it is easy and only results in correction at low gain.

According to the present invention, an ideal position is calculated in accordance with an ideal servo system model, and the accumulated position of the position feedback or the ideal servo system model is multiplied by gain and gain for a predetermined time from the time of reversing the direction of the abnormal position. By applying this as a correction amount to the current command, a spring-based element such as torsion of the ball screw dissipates the load torque in a large machine, and is corrected in proportion to the accumulated position from the reversal of the direction, and the spring such as elastic deformation. It is difficult to generate a pitting due to overcompensation even for a mechanical system having an element, and stable correction can be made even for changes in speed or friction load.

According to the present invention, the speed feedback or the speed of the ideal servo system model is multiplied by a predetermined gain only from a time when the direction of the abnormal position is reversed, and the current is applied as a correction amount to become the dominant at high speed. Since the correction by the viscosity term is provided, the spring-based element can be stabilized and the high-precision correction can be made against the speed change.

In addition, according to the present invention, since the coefficient is used in proportion to the difference between the abnormal position and the actual feedback position, the spring-based element such as torsion of the ball screw causes the load torque to be eliminated in the large machine. Correction is made in proportion to the accumulated position from the inversion, and it is difficult to create a dent due to overcompensation even for a mechanical system having a spring element such as elastic deformation, and stable correction is also possible for changes in breaking speed or friction load. As well as being possible, the spring constant or viscosity constant that determines the correction amount can be changed by the error of the abnormal position, so that a system can be constructed to cope with the secular variation of the spring constant or viscosity constant or the machine condition change.

As described above, the servo control method and the apparatus according to the present invention are suitable for use in the servo control of a mechanical system having a large change in elasticity such as twisting of a ball screw or a real substance.

Claims (14)

The servo generates the current command according to the difference between the position command and the actual position feedback, and generates a current command according to the difference between the speed command and the actual speed feedback and controls the servo motor according to the current command. In the control method, The ideal position is calculated according to the ideal servo system model, and the difference between the calculated abnormal position and the actual position feedback is multiplied by a predetermined gain only for a predetermined time from the time of inversion of the abnormal position, and the speed command Servo control method characterized in that the addition to the correction amount. The method of claim 1, And the gain is attenuated at a predetermined time as a maximum value when the direction of the abnormal position is reversed. The method according to claim 1 or 2, A servo control method characterized by storing the difference between the abnormal position and the actual position feedback at the time of inversion of the abnormal position as an offset value, and subtracting the difference by this offset value and multiplying the subtracted gain by this gain. . The servo generates the current command according to the difference between the position command and the actual position feedback, and generates a current command according to the difference between the speed command and the actual speed feedback and controls the servo motor according to the current command. In the control method, The ideal position is calculated according to the ideal servo system model, and the current feedback is multiplied by a predetermined gain by a predetermined gain only for a predetermined time from the time of reversing the direction of the calculated ideal position. Servo control method characterized in that the addition. The method of claim 4, wherein Only for a predetermined time from when the direction of the abnormal position is reversed. And multiplying the speed of the speed feedback or the ideal servo system model by a predetermined gain and applying this to the current command as a correction amount. The method according to claim 4 or 5, And a coefficient proportional to the difference between the abnormal position and the actual feedback position. The method according to any one of claims 1, 2, 4, and 5, The ideal servo system model is a model that considers the delay of the position loop system from the position command to the position feedback and the mechanical delay of the controlled object. Means for detecting the position and speed of the servomotor, a position control unit for generating a speed command according to the difference between the position command and the actual position feedback, and a current command according to the difference between the speed command and the actual speed feedback. In the servo control device for controlling the servo motor having a speed control unit for generating a; and a current control unit for controlling the current flowing to the servo motor in accordance with the current command, Subtraction means for outputting the difference signal between the ideal servo system model, the abnormal position calculated by this model and the actual position feedback, and the difference signal outputted from this subtraction means from a time when the direction of the abnormal position is reversed. However, the servo control apparatus provided with the means which multiplies a predetermined gain, and adds this as a correction amount to the said speed command. The method of claim 8, And the gain is attenuated at a predetermined time as a maximum value when the direction of the abnormal position is reversed. The method according to claim 8 or 9, A storage means for storing the difference between the abnormal position and the actual position feedback at the time of inversion of the abnormal position as an offset value, a subtraction means for subtracting the difference from the offset value stored in the storage means, and the subtraction means. And subtracted from the multiplier to multiply the gain. Means for detecting the position and speed of the servomotor, a position control unit for generating a speed shift according to the difference between the position command and the actual position feedback, and a current command according to the difference between the speed command and the actual speed feedback. In the servo control device for controlling a fraudulent servo motor having a speed control unit for controlling the current, and a current control unit for controlling the current flowing to the servo motor in accordance with the current command, And a means for multiplying the position feedback or the accumulated position of the ideal servo system model by a predetermined gain and applying it as a correction amount to the current command only between the ideal servo system model and a predetermined time from the inversion of the abnormal position of the model. Servo controller. The method of claim 11, wherein Sebo control characterized in that it comprises a means for multiplying the speed of the speed feedback or the ideal servo system model by a predetermined gain only from a time when the direction of the abnormal position of the model is reversed, and applying this as a correction amount to the current command. Device. The method according to claim 11 or 12, And a coefficient proportional to the difference between the abnormal position and the actual feedback position for the gain. The method according to any one of claims 8, 9, 11, and 12, The ideal servo system model is a model that considers the delay of the position loop system from the position command to the position feedback and the mechanical delay of the controlled object.