JPH0424810A - Servo control system - Google Patents

Abstract

PURPOSE:To improve the response characteristic by feeding positively the position deviation compensating signal produced in response to the position deviation obtained by a position deviation arithmetic means back to the input or output side of a position control means in order to compensate the position deviation and to correct a velocity command signal. CONSTITUTION:A position steady deviation compensation arithmetic part 11 outputs a position steady deviation compensation signal alphap to an adder 2 against the input of a position deviation signal epsilonp in accordance with a prescribed correction function f (epsilonp). The adder 2 inputs both signals alphap and epsilonp to add them together and outputs a new position deviation signal (epsilonp + alphap) to a position control part 3. This new deviation signal functions to eliminate the position steady deviation of a position control loop system in a servo control system. Thus the part 3 can compensate the position steady deviation according to its fluctuation if caused occasionally by the inertia variation of the mechanical load, the variation of the frictional torque, etc., of a control subject. Then the high speed response characteristic can be improved in the position control loop system.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a servo control system for controlling the drive of a servo motor, and particularly to a servo control system that can compensate for steady deviations in position and speed within a servo control loop. Regarding the servo control system.

[Prior Art] Conventionally, a servo control system uses a deviation counter to count the positional deviation between a position command signal that commands a target position and a feedback position signal from a position detector installed in a servo motor, and then calculates the position according to this deviation. The servo motor is driven and controlled according to the speed deviation between the speed command signal and the feedback speed signal of the servo motor. By the way, in a servo control system, due to the mechanical load of the controlled object,
When the position command signal changes, the controlled object follows it with a delay, resulting in a problem of steady-state deviation. Therefore, for example, there is a problem that the contour accuracy during control is lowered and the radius is reduced even when cutting a perfect circle.

In order to solve this problem, there is a servo control system that employs feedforward control. There are two types of feedforward control: one that compensates for a steady-state deviation that occurs when a controlled object follows a change in a command signal with a delay, and the other that compensates for disturbance input.

FIG. 7 is a block diagram showing a schematic configuration of a conventional servo control system in which a feedforward system compensation loop for compensating for deviations is added to a normal feedback control system.

The servo motor 8 is, for example, an AC servo motor. A position detector 9 is coupled to the servo motor 8 to detect its current position. The current position signal PF is outputted from the position detector 9 to the subtracter 1 and the speed calculation section 1o.

The speed calculation unit 10 calculates a current speed signal VF indicating the rotational speed of the servo motor 8 based on the current position signal PF, and outputs it to the subtracter 4. Instead of the speed calculating section 10, there is also one in which a speed sensor (pulse generator) for detecting the current speed is coupled to the servo motor 8.

The subtracter 1 inputs the position command signal Pc indicating the target position of the servo motor 8 and the current position signal PF from a higher-level controller (not shown), subtracts the current position signal PF from the position command signal Pc, and calculates the position deviation. It is output to the position control section 3 as a signal εp.

The position control section 3 outputs a speed command signal V c 1 according to the position deviation signal εp to the adder 42 . At this time, the feedforward loop 41 performs a predetermined calculation (
The position command signal Pc is differentiated and multiplied by a predetermined coefficient, etc.), and a speed compensation signal vc2 for removing the steady deviation of the position is output to the adder 42. Therefore, the adder 42 outputs a speed command signal Vc3 in which the speed compensation signal Vc2 for compensating for the steady position error is added to the normal speed command signal Vcl. Subtractor 4 receives speed command signal Vc3
and the current speed signal VF, and the speed command signal V c 3
The current speed signal VF is subtracted from the current speed signal VF, and a speed deviation signal εV is output to the speed control section 6. The speed control unit 6 receives a speed deviation signal ε
A torque command signal (current command signal) Tc for the servo motor 8 according to V is output to the current control section 7. The current control section 7 drives the power transistor and supplies a drive current to the servo motor 8.

The steady-state deviation that causes control delay depends on the mechanical load of the controlled object, so in order to advance the control in advance, the speed should be adjusted with respect to the speed command signal Vcl so that the predicted steady-state deviation can be compensated. The compensation signal Vc2 is fed back positively.

[Problem to be solved by the invention]

The above-mentioned conventional technology attempts to eliminate the first-order delay element of the position loop and achieve high-speed responsiveness of servo control by variably setting the coefficient of the feedforward loop 41 according to the predicted steady-state deviation. Such compensation is effective when there is no variation in the mechanical load and the steady-state deviation is constant.

However, 1. In a normal servo control system, this steady-state deviation is not constant, and is caused by inertia fluctuations in the mechanical load to be controlled and fluctuations in frictional torque (during cutting with a machine tool, lifting different heavy objects with a robot arm, etc.) It changes from time to time depending on the situation). Therefore, if conventional constant positive feedback compensation is applied to a feedback loop where the steady-state error fluctuates from time to time, the variation in the steady-state error cannot be fully compensated for, and unexpected nonlinear phenomena or vibrations may occur. Sometimes I do.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a servo control system with high-speed response characteristics that can perform deviation compensation according to fluctuations in steady-state deviation.

[Means to solve the problem]

The servo control system according to the present invention includes a position deviation calculating means for calculating a position deviation by negatively feeding back a feedback position signal indicating the current position of the servo motor with respect to a position command signal, and generating a speed command signal according to the position deviation. position control means for
comprising a speed deviation calculation means for calculating a speed deviation by negatively feeding back a feedback speed signal indicating the current speed of the servo motor with respect to the speed command signal, and a speed control means for generating a current command signal according to the speed deviation, In a servo control system that drives and controls a servo motor according to this current command signal,
positional deviation compensation signal generating means for generating a positional deviation compensation signal in accordance with the positional deviation determined by the positional deviation calculating means; and positive feedback of the positional deviation compensation signal to at least one of the input side and the output side of the positional control means. The present invention further comprises a correction means for compensating for the positional deviation by adjusting the speed command signal, thereby correcting the speed command signal.

Furthermore, the speed deviation compensation signal generating means generates a speed deviation compensation signal according to the speed deviation obtained by the speed deviation calculation means, and the speed deviation compensation signal is transmitted to the input side and the output side of the speed control means. The present invention further includes second correction means for compensating for speed deviation by providing positive feedback to at least one side, thereby correcting the current command signal.

[Operation] The positional deviation obtained by the positional deviation calculating means is that of a feedback loop (position control loop) system that includes a mechanical load. The positional deviation compensation signal generating means generates a positional deviation compensation signal in accordance with this positional deviation, and the correction means positively feeds this positional deviation compensation signal to at least one of the input side and output side of the position control means. Therefore, when the position error compensation signal is positively fed back to the input side of the position control means,
The position control means inputs a signal obtained by adding a position deviation compensation signal to the position deviation as a new deviation signal, and generates a speed command signal based on the signal.

At this time, the new position error input to the position control means is a signal with the steady position error compensated, so the position control means outputs a speed command signal with the steady position error compensated for in the position control loop system. Even if the steady-state positional deviation fluctuates due to the influence of mechanical load or the like, the positional deviation compensation signal also fluctuates in the same way, so the fluctuation in the steady-state positional deviation can be effectively compensated for.

Furthermore, when the position deviation compensation signal is positively fed back to the output side of the position control means, the speed command signal output from the position control means is added with a speed command signal corresponding to the position deviation compensation signal to control the speed of the primary stage. It becomes input to the means. At this time, the new speed command signal input to the speed control means is a speed command signal with steady position deviation compensated, so it is as if the position control means outputs a speed command signal with steady position deviation compensated for in the position control loop system. It looks like it is. Therefore, even if the steady position error fluctuates due to the influence of mechanical load, etc., the position error compensation signal will also fluctuate in the same way.
Since a speed command signal based on this is output, it is possible to effectively compensate for fluctuations in the steady position error.

Furthermore, the speed deviation obtained by the speed deviation calculation means is that of a feedback loop (speed control loop) system including a mechanical load. The speed deviation compensation signal generating means generates a speed deviation compensation signal in response to this speed deviation, and the correcting means positively feeds back this speed deviation compensation signal to at least one of the input side and the output side of the speed control means. Therefore, when the speed deviation compensation signal is positively fed back to the input side of the speed control means, the speed control means inputs a signal obtained by adding the speed deviation compensation signal to the speed deviation as a new deviation signal.

A current command signal is generated based on the stiffness. At this time, the new speed deviation input to the speed control means is a signal with the steady speed deviation compensated, so the speed control means generates a current command signal with the steady speed deviation compensated for in the speed control loop system. Even if the steady-state speed deviation fluctuates due to the influence of mechanical load, etc., the speed deviation compensation signal also fluctuates in the same way, so the fluctuation in the steady-state speed deviation can be effectively compensated for.

Furthermore, when the speed deviation compensation signal is positively fed back to the output side of the speed control means, a current command signal corresponding to the speed deviation compensation signal is added to the current command signal output from the speed control means, and the current control signal of the next stage is It becomes input to the means. At this time, the new current command signal input to the current control means is a current command signal with the steady-state speed error compensated for, so it is as if the speed control means outputs a current command signal with the steady-state speed error compensated for in the speed control loop system. It looks like it is. Therefore, even if the steady speed deviation fluctuates due to the influence of mechanical load, etc., the speed deviation compensation signal will also fluctuate in the same way.
Since a current command signal based on the current command signal is output, it is possible to effectively compensate for fluctuations in the steady speed error.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing an embodiment of the servo control system of the present invention.

The servo motor 8 is, for example, a synchronous AC servo motor. A position detector 9 is coupled to the servo motor 8 for absolutely detecting its current position. Further, although not shown, a mechanical load such as a machine tool is coupled to the servo motor 8. Therefore, even in a semi-closed loop configuration where the position detector 9 is coupled to the servo motor 8 and feeds back the current position of the servo motor 8, it is coupled to a mechanical load such as a machine tool and feeds back the current position of the machine tool. It may have a fully closed loop configuration.

As this position detector 9, for example, Japanese Patent Laid-Open No. 57-704
An inductive phase shift type position sensor as shown in Japanese Patent No. 06 may be used. In that case, the output of the position detector 9 consists of an AC signal whose electrical phase is shifted according to the current position, and this output is input to the converting means 13, where it is converted into a digital current position signal PF, and the speed calculation section 10 and the subtracter 1.

The speed calculation unit 10 calculates a current speed signal VF indicating the rotational speed of the servo motor 8 based on the current position signal PF, and outputs it to the subtracter 4. Instead of this speed calculating section 10, a speed sensor (pulse generator) for detecting the current speed may be coupled to the servo motor 8.

The subtracter 1 inputs a position command signal Pc indicating the target position of the servo motor 8 and a current position signal PF indicating the current position of the servo motor 8 from a higher-level controller (not shown), and generates a current position signal from the 1 position command signal Pc. PF is subtracted and one position deviation signal εp is output to the position control section 3 and the steady position deviation compensation calculation section 11.

The steady position error compensation calculation unit 11 inputs the position error signal εp, and outputs the steady position error compensation signal αp to the adder 2.

The steady-state positional deviation compensation calculation unit 11 generates a positional deviation signal ip according to a predetermined correction function f(ip) as illustrated in FIG.
A steady-state position error compensation signal αp is output for the input.

Speed steady deviation compensation signal α of the speed steady deviation compensation calculation unit 12
V may be input to the steady position error compensation calculation section 11, and in that case, the characteristics of the correction function shown in FIG. You can. That is, the steady position error compensation signal αp changes according to the formula αp=K(αV)·f(εp). K
(αV) is a constant that changes the slope of the correction function f(εp) according to the magnitude of the speed steady-state error compensation signal αV;
It is possible to make an appropriate selection depending on the state of the mechanical load coupled to the machine. For example, when the speed steady-state error compensation signal αV is less than or equal to a predetermined value, K(αV) is a constant value, and when it is greater than or equal to the predetermined value, it is a value that decreases according to a linear function characteristic. As a result, optimum position steady-state deviation compensation control can be performed according to the control state of the speed steady-state deviation compensation calculation section 12.

Note that the characteristics of the correction function of the steady-state positional deviation compensation calculation unit 11 are two functions: it changes like a cubic function near zero where the positional deviation signal ip is small, and saturates as the positional deviation signal [P becomes larger than a predetermined value. It consists of a combination of

The adder 2 inputs the positional deviation signal εp and the steady-state positional deviation compensation signal αP, and generates a new positional deviation signal (ε
P+αP) is output to the position control section 3. Since this new position error signal (εP+αP) is a signal for removing the steady position error in the position control loop system of the servo control system, the position control unit 3 Even if the steady-state positional deviation changes from time to time due to fluctuations, the steady-state positional deviation can be compensated for according to the variation, and the high-speed response characteristics of the position control loop system can be improved.

The position control unit 3 calculates a speed command signal Vc corresponding to this position deviation signal (εP+αP) and outputs it to the subtracter 4. Therefore, the 1-position control section 3 outputs the speed command signal Vc from which the steady position deviation of the position control loop system has been removed to the subtracter 4.

The subtracter 4 inputs the speed command signal Vc and the current speed signal VF, and subtracts the current speed signal VF from the speed command signal Vc.
The speed deviation signal tv is output to the adder 5 and the speed steady-state deviation compensation calculation section 12.

The speed steady deviation compensation calculation unit 12 inputs the speed deviation signal EV and outputs the speed steady deviation compensation signal αV to the adder 5 and the position steady deviation compensation calculation unit 11.

The steady speed deviation compensation calculation unit 12 outputs the steady speed deviation compensation signal αV in response to the input speed deviation signal εV according to a predetermined correction function f(εV) as shown in FIG. The characteristic of this correction function f(iv) is that it changes like a cubic function near zero where the speed deviation signal εV is small, and saturates as the speed deviation signal εV becomes larger than a predetermined value.
It is composed of a combination of two functions, and has approximately the same characteristics as the positional steady-state error compensation calculation section 11.

The adder 5 inputs the speed deviation signal tv and the speed steady-state deviation compensation signal αV, and generates a new speed deviation signal (i
v+αV) is output to the speed control section 6. This new speed deviation signal (εV + αV) is a signal for removing the steady speed deviation in the speed control loop system of the servo control system. Even if the steady-state speed deviation fluctuates from time to time due to torque fluctuations, the steady-state speed deviation can be compensated for in accordance with the fluctuation, making it possible to improve the high-speed response characteristics of the speed control loop system.

The speed control unit 6 generates a torque command signal (current command signal) T for the servo motor 8 according to this speed deviation signal (εV+αV).
c is calculated and output to the current control section 7. Therefore, the speed control section 6 outputs the torque command signal TC from which the speed steady-state deviation of the speed control loop system has been removed to the current control section 7.

The current control section 7 drives the power transistor and supplies a drive current to the servo motor 8.

Note that the characteristics of the steady position deviation compensation calculation unit 11 and the steady speed deviation compensation calculation unit 12 shown in FIGS. 2 and 3 are merely examples, and may be changed as appropriate depending on the servo motor 8 and the mechanical load connected thereto. For example, a linear function, a quadratic function, a third or higher order function, an exponential function, or a linear approximation thereof can be considered.

Furthermore, in the embodiment shown in FIG. 1, a case has been described in which the steady deviation of the position and speed of both the position control loop system and the speed control loop system is compensated, but the present invention is not limited to this, and the steady deviation of either one is compensated. It goes without saying that even if configured to do so, the effects of the present invention can be achieved.

FIG. 4 is a diagram showing an absolute type position sensor consisting of an inductive phase shift type position sensor, which is an example of the position detector 9 of FIG. 1. The details of this position detector 4 are known from Japanese Patent Application Laid-Open No. 70406/1982, so a brief explanation will be given here.

The position detector 9 is inserted into a stator 23 in which a plurality of poles A-D are provided at predetermined intervals (for example, 90 degrees) in the circumferential direction, and a space of the stator 23 surrounded by various poles A-D. and a rotor 24.

The rotor 24 is made of a shape and material that change the reluctance of various types A-D depending on the rotation angle, and has an eccentric cylindrical shape, for example. Primary coils IA to ID and secondary coils 28 to 2D are wound around each type of stator 23 A to D, respectively. The first pair of poles A and C and the second pair of poles B and B, which are radially opposed to each other, are wound with coils so as to operate differentially. It is configured such that a roughtance change occurs.

The primary coils IA and IC wound around the first pole pair A and C are excited by a sinusoidal signal sinωt, and the primary coils IB and IC wound around the second pole pair B and D are excited by the sinusoidal signal sinωt. It is excited by a cosine signal cosωt. As a result, a composite output signal Y is obtained from the secondary coils 2A to 2D. This composite output signal Y is a primary AC signal (primary coil excitation signal) sinω or cosω, which is a reference signal.
With respect to t, a signal Y=sin (ω is 10) whose phase is shifted by an electrical phase angle corresponding to the rotation angle θ of the rotor 24
It is.

Therefore, when using an inductive phase shift type position sensor as described above, the primary AC signal sinω or cos
It is necessary to provide an AC signal generating means for generating ωt and a phase difference measuring means for measuring the electrical phase shift θ of the single composite output signal Y and calculating the rotor position data. The primary alternating current signal generating means and the phase difference measuring means are provided in the converting means 13.

FIG. 5 is a diagram showing an example of the converting means 13 shown in FIG. 1.

In the conversion means 13, a predetermined high speed clock pulse C
P is counted by a counter 26, and based on the output of the counter 26, a sine/cosine signal generating means 27 generates a sine signal sinω and a cosine signal cosωt, respectively. The output of the sine/cosine signal generating means 27 is output from the primary coils lA to ID and the secondary coils 2A to 2 as described above.
D.

A composite output signal Y=sin (ω=−θ) of the secondary coils 2A to 2D is given to the zero cross detection means 28. The zero cross detection means 28 outputs a pulse L in synchronization with the timing when the electrical phase angle of the composite output signal Y is zero. Pulse L is used as a latch pulse for latch circuit 29.

Therefore, the latch circuit 29 latches the count value of the counter 26 in response to the rise of the pulse L. counter 26
The period during which the count value of
Synchronize with the local phase. Then, the latch circuit 29 receives the reference AC signal sinωt and the composite output signal Y=sin(ωt−
The count value corresponding to the phase difference θ with respect to θ) is latched. Therefore, the latched value is output as digital position data Dθ. Note that the latch pulse L can also be used as a timing pulse as appropriate.

Further, among the values latched by the latch circuit 29, a value indicating the absolute position within one rotation of the servo motor is output as digital phase data P3, and is used for field switching position control.

The composite output signal P1 of the phase shift type position sensor as shown in FIG. 4 uses the absolute position of the servo motor as the phase difference of the signal, so it has the characteristic that it is not easily affected by noise. , when the composite output signal P1 is fed back from the position detection 199 to the position and speed control system 1.

This is acceptable because it provides direct feedback without using a communication line and is not affected by noise or the like.

However, the combined output signal P1 of the position detector 9 may be fed back using a communication line such as a serial communication interface.

Although FIGS. 4 and 5 are for absolute detection in the range of one rotation, it is preferable to combine a plurality of such absolute sensors to detect the absolute position over multiple rotations.

Next, another embodiment of the present invention will be described using FIG. 6. In FIG. 6, the same components as in FIG. 1 are denoted by the same reference numerals, so the explanation thereof will be omitted.

The difference between this embodiment and the one shown in FIG. The characteristics of the correction function of the 0-position steady-state error compensation calculation unit 11 that is output to the adder 61 provided at the subsequent stage may be approximately the same as that shown in FIG. is configured to print. The adder 61 receives the speed command signal Vc1 output from the position control section 3.
and the steady position error compensation speed signal Vc2 are added.

It is output to the subtracter 4 as a new speed command signal V c 3. Therefore, since the new speed command signal Vc3 is a speed signal for removing steady-state position deviation in the position control loop system of the servo control system, the position is not steady due to inertia fluctuations of the mechanical load of the controlled object, fluctuations in friction torque, etc. Even if the deviation fluctuates from time to time, the steady-state positional deviation can be compensated for in accordance with the fluctuation, making it possible to improve the high-speed response characteristics of the position control loop system.

The steady speed deviation compensation calculation section 12 outputs a steady speed deviation compensation torque signal Tc2 for compensating the steady speed deviation to the adder 62 and the steady position deviation compensation calculation section 11 provided at the subsequent stage of the speed control section 6. Speed steady deviation compensation calculation section 1.2
Although the characteristics of the correction function may be approximately the same as those shown in FIG. 3, it is configured to output a torque signal according to the speed deviation signal εV. The adder 62 adds the torque command signal Tel output from the speed control section 6 and the steady speed deviation compensation torque signal Tc2, and outputs the result to the current control section 7 as a torque command signal Tc3. This new torque command signal T c 3 is a signal for removing steady-state speed deviations in the speed control loop system of the servo control system, so the steady-state speed may change due to inertia fluctuations of the mechanical load to be controlled, fluctuations in friction torque, etc. Even if the deviation fluctuates from time to time, the steady-state speed deviation can be compensated for in accordance with the fluctuation, making it possible to improve the high-speed response characteristics of the speed control loop system.

With this configuration, it is possible to compensate for steady deviations in position and speed in the position control loop system and the speed control loop system, as in the embodiment shown in FIG. 1, and to perform deviation compensation according to fluctuations in the deviations. be able to.

It goes without saying that the servo motor is not limited to a synchronous type servo motor, but may also be an induction type AC servo motor, and is not limited to an AC servo motor, but may also be of other types such as a DC servo motor. The position sensor is not limited to an inductive phase shift type sensor, but an optical absolute encoder, an incremental encoder, or other types of sensors may also be used.

In the above-described embodiment, a case has been described in which the steady position deviation compensation calculation unit 11 and the steady speed deviation compensation calculation unit 12 are provided, but it is not necessarily necessary to provide both, and the effect can be sufficiently achieved by providing either one of them. It is possible.

However, it goes without saying that deviations can be removed more effectively by providing both as in this embodiment and changing the control characteristics of the steady position deviation compensation calculation section 11 in accordance with the output of the steady speed deviation compensation calculation section 12. do not have.

In addition, in the embodiment shown in FIG.
outputs the steady position deviation compensation signal αp, and the steady speed deviation compensation calculation unit 12 outputs the steady speed deviation compensation signal αV, and in the embodiment of FIG. 6, the steady position deviation compensation calculation unit 11 outputs the steady position deviation compensation speed signal V c 2, speed steady-state deviation compensation calculation unit 1
2 outputs the speed steady deviation compensation torque signal Tc2 separately, but the present invention is not limited to this, and the position steady deviation compensation calculation unit 11 outputs the steady position deviation compensation signal αP and the steady position deviation compensation torque signal Tc2. It goes without saying that the configuration may be such that the signal Vc2 is output, and the steady speed deviation compensation calculation section 12 outputs the steady speed deviation compensation signal αV and the steady speed deviation compensation torque signal Tc2.

〔Effect of the invention〕

According to the present invention, even if the steady-state deviation in each of the position control loop system and speed control loop system of the servo control system fluctuates, the steady-state deviation can be effectively compensated for, and the servo control system has excellent high-speed response. It has the excellent effect of being able to compose.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the schematic configuration of an embodiment of the servo control system of the present invention, FIG. 2 is a diagram showing the output characteristics of the positional steady-state error compensation calculation section of FIG. 1, and FIG. 3 is the same as that of FIG. FIG. 4 is a cross-sectional view showing an absolute type position sensor consisting of an inductive phase shift type position sensor, which is an example of the position sensor shown in FIG. 5 is a block diagram showing an example of the conversion means in FIG. 1, FIG. 6 is a block diagram showing another embodiment of the present invention, and FIG. 7 is a block diagram showing a schematic configuration of an example of a conventional servo control system. It is. DESCRIPTION OF SYMBOLS 1... Subtractor, 2... Adder, 3... Position control section, 4... Subtractor, 5... Adder, 6... Speed control section, 7... Current control Part, 8... Servo motor, 9.
. . . Position detector, 10 . . . Speed calculation section, 11 . . . Steady position deviation compensation calculation section. 12... Steady speed deviation compensation calculation unit, 13... Conversion means patent applicant: Nisgy Co., Ltd. Representative, Patent attorney: Yoshihito Iizuka

Claims (5)

[Claims] (1) a position deviation calculation means for calculating a position deviation by negatively feeding back a feedback position signal indicating the current position of the servo motor with respect to the position command signal; a position control means for generating a speed command signal according to the position deviation; positional deviation compensation signal generating means for generating a positional deviation compensation signal in accordance with the positional deviation determined by the positional deviation calculating means; and positive feedback of the positional deviation compensation signal to at least one of the input side and the output side of the positional control means. correction means for compensating for the positional deviation by adjusting the speed command signal and thereby correcting the speed command signal; and speed deviation calculation means for calculating the speed deviation by negatively feeding back a feedback speed signal indicating the current speed of the servo motor with respect to the speed command signal. , a speed control means that generates a current command signal according to the speed deviation, a current control means that generates a drive current according to the current command signal, a servo motor driven by this drive current, and a current state of this servo motor. A servo control system comprising detection means for detecting position and velocity and outputting the return position signal and return velocity signal. (2) The servo control system according to claim 1, wherein the positional deviation compensation signal generating means generates the positional deviation compensation signal according to the positional deviation according to a predetermined compensation function. (3) The servo control system according to claim 2, wherein the compensation function is controllable by variably controlling its coefficients. (4) speed deviation compensation signal generating means for generating a speed deviation compensation signal in accordance with the speed deviation determined by the speed deviation calculation means; 2. The servo control system according to claim 1, further comprising second correction means for correcting the current command signal by compensating for the speed deviation by providing positive feedback to the current command signal. (5) In generating the positional deviation compensation signal according to the positional deviation, the positional deviation compensation signal generating means includes:
The servo control system according to claim 4, wherein the position deviation compensation signal is generated using the speed deviation compensation signal as a parameter.