Servo motor control system that improves the machining precision of multiple axes

Abstract

A servomotor control system (1) in a machine tool or an industrial machine, which uses coordinated operations of several axes comprising two mutually orthogonal axes (X, Y) driven by servomotors (12, 14) to machine a workpiece in the form of a closed figure with a convex surface or a columnar or conical element positioned parallel to this closed figure at an upper end and a lower end, wherein the servomotor control system (1) comprises: a host control device (24) that generates position command values ​​(Pc) for machining the workpiece at each predetermined sampling period; a servo control system (10) that uses the position command values ​​(Pc) as the basis for driving the servomotors (12, 14) of the axes to actuate a driven element that processes the workpiece; Position detectors (27, 31) that detect the positions (Pf) of the servomotors (12, 14) or a position of the driven element; a position error calculation section (35) that calculates a position error (Er) between position command values ​​(Pc) and the detected positions (Pf) of the servomotors (12, 14); a reference angle generation section (4, 5, 6) and learning control sections for learning control (26, 30), wherein the reference angle generation section (4, 5 and 6) is configured to: to designate any position within a closed figure formed by the position command value as the center point P and to define this coordinate from the origin (0,0) as P(Xo, Yo), to designate a point S, which is an editing point on the closed figure one editing period before a current editing period, and to define these coordinates as S(Xs, Ys), to designate a processing point M at which the processing is carried out during the current processing period and to define these coordinates as M(Xm, Ym), The lengths PS, SM and MP, as the sides of a triangle connecting points S, M and P, can be calculated using the following formulas: PS = ( (Xs − Xo ) 2 + ( Ys − Yo ) 2 ) 1 / 2 SM = ((Xm − Xs) 2 + (Ym − Ys) 2) 1 / 2, and MP = ( (Xo − Xm ) 2 + ( Yo − Ym ) 2 ) 1 / 2 , The quantity of change Δθ per sampling period of the reference angle θn between the two sides PS and MP can be calculated using the following formula: Δ θ = arccos ( MP 2 + PS 2 − SM 2 ) / ( 2 * MP * PS ) , and to calculate a reference angle θn, which increases or decreases monotonically from a reference point on the closed figure and a current processing point at a predetermined sampling period "n", as the cumulative value of the change quantity Δθ; and wherein the learning control sections (26, 30) are configured to perform a learning control of the angle synchronization type based on reference angle θn and position error (Er).

Description

GENERAL STATE OF THE ART1. Field of the invention

[0001] The present invention relates to a servo motor control system for controlling a machine tool or other machine. In particular, the present invention relates to a servo motor control system in which several axes driven by servo motors are coordinated to improve machining precision when machining a closed curve or polygon. 2. Description of the state of the art

[0002] Generally, when drilling on a machining center or other machine tool, a dedicated drilling tool is used to improve precision. The drilling tool must be selected according to the diameter of the hole being drilled. Therefore, when drilling holes of several different diameters, multiple drilling tools are required.

[0003] Typically, a machining center equipped with a numerical control (CNC) is provided with an automatic tool changer (ATC). The ATC can be equipped with multiple tools, allowing for automatic tool changes in accordance with the operation. However, there is a limit to the number of tools that can be mounted on an ATC. Therefore, if an operation requires a tool not stored on the ATC, time is required to change the tool. This can lead to problems such as decreased productivity.

[0004] In contrast, there is a method for replacing a drilling operation with a milling operation. One such alternative to milling is helical machining. Helical machining utilizes a face mill suitable for the diameter of the hole to be drilled, performing a helical arc motion to create the bore. In helical machining, this arc motion is generally achieved by coordinated drive actuation of a workpiece-carrying table by servo motors in the X- and Y-axis directions.

[0005] When using a helical machining operation to drill a hole, even if multiple holes of different diameters are being drilled, the advantage is that a single face milling machine can handle the operation. On the other hand, a helical machining operation is accompanied by arc movement of the table, so that if the speed is increased, quadrant disturbance (delay in the moment of reversal of the drive axis) can occur due to the delayed response of the X-axis and Y-axis servo motors that drive the table, or due to lost machine movement (oscillation or torsion), resulting in a deterioration of precision.

[0006] As a method to counteract this deterioration in precision, the most effective approach is to utilize the fact that, during a helical machining operation, the face mill repeatedly moves in an arc, and to apply adaptive control to control the servomotors of the X and Y axes. In particular, it is effective to apply adaptive control of the angle synchronization type, as it allows for handling variations in machining speed, as in the servomotor drive control system disclosed in Japanese patent JP 4 043 996 B. However, in this case, angular information is required as the basis for the learning period of the control. The reference angle must be monotonically increasing or monotonically decreasing, but in the case of arc movement of a face mill through the two axes X and Y, there is no information (no signal) that can be used as this reference angle.

[0007] To solve this problem, Japanese patent JP 49 804 532 B discloses a servo control system that cumulatively adds the X-axis or Y-axis control values ​​or absolute values ​​of the feedback values ​​to create information (signal) at the reference angle.

[0008] The servo control system disclosed in Japanese patent JP 4 980 453 B, however, has the problem that it is unable to handle cases where the diameter of the arc changes slowly. This problem arises because the learning control requires the learning period (e.g., 360 degrees, etc.) as projected information to store data corresponding to the repetition period of the command value. However, when preparing a signal corresponding to the reference angle from the command values ​​or feedback values, the angle indicated by the signal is not the angle from the center, but rather the amounts of movement along the X and Y axes. Therefore, if the diameter of the circle changes, the changes in movement will also change.In the servo control system disclosed in Japanese patent JP 4 980 453 B, the period of the projected information and the actual amount of movement no longer match, and correct adaptive control is no longer possible.

[0009] In a helical machining process, for example, when a face milling cutter, as in Fig. Figure 1A illustrates that when circular motion begins, it is (easily) possible to calculate the amount of motion of the face milling cutter corresponding to the learning period of the diameter of circle "c". However, in a helical machining operation, when a face milling cutter begins its motion, it follows a free closed curve L and not a simple circle, as shown in Figure 1A. Fig. Figure 1B illustrates that calculating the amount of movement of the face milling cutter is not easy.

[0010] DE 10 2011 111 952 A1 describes a servo control system that enables angle-based learning control for complex machine tool paths by generating a continuously increasing reference signal from the tool geometry, even if individual axis movements are not monotonic.

[0011] It is an object of the invention to propose a servomotor control system for improving the machining precision of multiple axes. This object is achieved by a servomotor control system according to claim 1. BRIEF SUMMARY OF THE INVENTION

[0012] It is an object of the present invention to provide a servomotor control system that enables the application of learning control of the angle synchronization type and the achievement of higher precision, even when a drilling operation is performed in which a diameter of the bore gradually changes, or even when a shape, such as a free closed curve, is machined instead of a simple arc.

[0013] The present invention provides a servomotor control system in a machine tool or industrial machine, which uses coordinated operations of several axes, including two mutually orthogonal axes driven by servomotors, to machine a workpiece positioned in the shape of a closed figure or as a columnar or conical element parallel to this closed figure at its upper and lower ends, comprising a host control device that generates a position command value for machining the workpiece, a servo controller that uses the position command value as the basis for driving the servomotors of the axes to actuate a driven element that machines the workpiece, and position detectors that detect the positions of the servomotors or a position of the driven element, and further comprising a position error calculation section.The system calculates the position error between the position command values ​​and the detected positions of the servo motors, and includes a reference angle generation section that designates any position within a closed figure, which the position command value defines as its center, and calculates a reference angle that monotonically increases or decreases from a reference point on the closed figure and a current machining point, as well as learning control sections that use the reference angle and the position error as the basis for performing learning control of the angle synchronization type.

[0014] According to the servomotor control system of the present invention, the system defines any point on the inside of a commanded closed curve, polygon, or other closed shape as the center, then calculates an angle from a reference point to the current machining point, and uses this for adaptive control of the angle synchronization type. Thus, in this case, if the period is 360 degrees, adaptive control becomes possible even if the diameter of the circle changes. According to the servomotor control system of the present invention, adaptive control of the angle synchronization type can therefore be applied and higher precision achieved even when machining a shape such as a closed curve or polygon, where its application was previously difficult. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be better understood with reference to the figures below. Fig. Figure 1A is a view illustrating the circular motion of a face mill during a helical machining operation. Fig. Figure 1B is a view illustrating the movement in a closed curve of a face milling cutter during a helical machining operation. Fig. 2A is a closed curve illustrating the shape of a workpiece to be machined by a machine tool equipped with a servomotor control system of the present invention. Fig. 2B is a polygon illustrating the shape of a workpiece to be machined by a machine tool equipped with a servomotor control system of the present invention. Fig. 2C is a column-shaped element that is provided at its upper and lower ends with surfaces surrounded by closed curves and illustrates the shape of a workpiece to be machined by a machine tool equipped with a servo motor control system of the present invention. Fig. 2D is a polygonal column illustrating the shape of a workpiece to be machined by a machine tool equipped with a servomotor control system of the present invention. Fig. 2E is a cone-shaped element which is provided at its upper and lower ends with closed curves of similar shapes and illustrates the shape of a workpiece to be machined by a machine tool which is provided with a servomotor control system of the present invention. Fig. Figure 2F illustrates a cone-shaped element which is provided at its upper and lower ends with polygons of similar shapes and illustrates the shape of a workpiece which is to be machined by a machine tool which is provided with a servomotor control system of the present invention. Fig. Figure 3 is a block diagram of an embodiment of a servomotor control system of the present invention. Fig. Figure 4 is a view illustrating a procedure for calculating a reference angle in the case where the machined shape is a closed curve. Fig. 5 is a flowchart illustrating the operation of a servo motor control system located in Fig. 3 is illustrated. Fig. Figure 6 is a block diagram of another embodiment of a servomotor control system of the present invention. DETAILED DESCRIPTION

[0016] The accompanying drawings are used below to explain the present invention in detail on the basis of specific embodiments, but before explaining the embodiments of the present invention, the Fig. 2A to 2F are used to explain the machined shapes of workpieces of a servomotor control system of the present invention.

[0017] The machined shapes of workpieces of the present invention have the following characteristics: (a) a closed curve L, as in Fig. Figure 2A illustrates this on any plane where the curves (line segments) do not intersect. (b) a polygon P as in Fig. 2B illustrates (c) a column-shaped element V1, as in Fig. 2C illustrates that closed curves have arcs that do not intersect at their top and bottom ends. (d) a column-shaped element V2, as in Fig. 2D illustrates that it has polygonal surfaces at its top and bottom ends. (e) a cone-shaped element V3, as in Fig. 2E illustrates that it is provided with closed curves with similar shapes at its upper and lower ends. (f) a cone-shaped element V4, as in Fig. Figure 2F illustrates that it is equipped with polygons having similar shapes at its top and bottom ends.

[0018] Here, the basic configuration of an embodiment of the servomotor control system 1 of the present invention is described using Fig. 3 explained. The servo motor control system 1 of the present invention comprises a host control device 24, a servo control system 10, and position detectors 27 and 31. The servo motor control system 1 is used in a machining center or other machine tool or industrial machine that has at least two axes that perform coordinated operations, such as an orthogonal X-axis and Y-axis. In this case, the servo control system 10 is provided with an X-axis servo control device 18 and a Y-axis servo control device 20.

[0019] Furthermore, a Z-axis servo control device is not essential in the servo motor control system 1 of the present invention, which is why its illustration has been omitted. It should be noted that if a Z-axis servo control device is provided, its function can be similar to that of a conventional servo control device. The Z-axis servo control device therefore detects the error between a Z-axis position command value sent by the host control device to perform predetermined machining and a position feedback value from the Z-axis servo motor or a tool or other driven element driven by the Z-axis servo motor, adds gain to this error, and uses the result as a Z-axis servo speed command to control the Z-axis servo motor.The position feedback value is obtained by a position detector that detects the Z-position of the Z-axis servo motor or the driven element.

[0020] When the servo control system 10 is equipped with the X-axis servo control device 18 and the Y-axis servo control device 20, the X-axis servo control device 18 and the Y-axis servo control device 20 use the different axes of position command values ​​(X-axis command and Y-axis command) Pc, which are sent by the numerical control device (NC) or other host control device 24, as the basis for preparing speed commands, and use these speed commands to control the servo motors 12 and 14.

[0021] The X-axis servo control device 18 has a learning control device 26 of the angle synchronization type. The learning control device 26 uses the error Er of a periodic X-axis position command value Pc, sent by the host control device 24 to perform predetermined machining, and a position feedback value Pf of the X-axis servo motor 12 or of a tool or other driven element (not illustrated) driven by the X-axis servo motor 12, as the basis for preparing a correction amount for controlling the X-axis servo motor 12. The correction amount is added to the error Er, then amplified by the gain Kp, and used as the X-axis servo speed command value for controlling the X-axis servo motor 12. The position feedback value Pf is obtained from the position detector 27, which detects the position of the X-axis servo motor 12 or the driven element.Furthermore, the X-axis servo control device 18 uses the reference angle θ sent by the host control device 24 as the basis for the learning control device 26 to perform the learning control. Details of the learning control are explained below.

[0022] Similarly, the Y-axis servo control device 20 has a device for learning control 30 of the angle synchronization type. The learning control device 30 uses the error Er of the periodic Y-axis position command value Pc, sent by the host control device 24 to execute predetermined machining, and a position feedback value Pf of the Y-axis servomotor 14 or a driven element (not illustrated) driven by the Y-axis servomotor 14 as the basis for preparing a correction amount to control the Y-axis servomotor 14. The correction amount is added to the error Er, then amplified by the gain Kp, and used as the Y-axis servo velocity command value to control the Y-axis servomotor 14. The position feedback value Pf is obtained from the position detector 31, which detects the Y-position of the Y-axis servomotor 14 or the driven element.Furthermore, the Y-axis servo control device 20 uses the reference angle θ, which is sent by the host control device 24, as the basis for the learning control device 30 to perform the learning control. Details of the learning control are explained below.

[0023] Here, a specific example of the configuration of the learning control device 26 in the X-axis servo control device 18 is explained. In the X-axis servo control device 18, the position error Er is calculated by an adder 35 from the position command value Pc, which is sent by the host control device 24, and the position feedback value Pf, which is sent by the position detector 27. The learning control device 26 detects the position error Er of the X-axis servo motor 12 or the driven element as the first position error in each predetermined sampling period (for example, 1 ms). The first position error Er is sent to the first conversion section 34 ( Fig. Section 3 describes this as “TIME→ANGLE CONVERSION,” whereby the first conversion section 34 converts the first position error Er into the second position error Er' for each reference angle position (explained below) of the driven element in one period. The first position error Er (time), which is associated with the sampling period, is converted into a second position error Er' (angle), which is associated with the reference angle position. This conversion technique is well-known, so the explanation is omitted.

[0024] The second position error Er' is increased by the first correction quantity from one period prior to the periodic actuation of the driven element, which is stored in the delay memory 36 for normally 360 degrees, and is then stored in the delay memory 36 as the first correction quantity c1. This first correction quantity c1 is sent to the second conversion section 38 ( Fig. Section 3 describes this as "ANGLE→TIME CONVERSION"), then the second conversion section 38 converts the first correction quantity c1 for each reference angle position into the second correction quantity c2 for each sampling period. The first correction quantity c1 (angle), which is linked to the reference angle position, is therefore converted into the second correction quantity c2 (time), which is linked to the sampling period. This conversion technique is well-known, so its explanation is omitted.

[0025] The adaptive control device 26 can be equipped with a band-limiting filter 40, which limits the band of the first correction quantity c1, and with a phase-adjustment filter 42, which compensates for the phase and for the gain of the second correction quantity c2 from the second conversion section 38, but these filters are not essential components. It should be noted that the band-limiting filter 40 is, in particular, a low-pass filter for attenuating the signal in the high-frequency range by a certain frequency range and thus improves the stability of the control system. Furthermore, the phase-adjustment filter 42 is a filter that advances the phase of the signal in the high-frequency range within a certain frequency range and also increases the gain, acting as compensation for delays in position control, speed control, current control, and other control systems, as well as for gain drops.It should be noted that the learning control device 30 of the Y-axis servo control device 20 can also be configured similarly to the learning control device 26.

[0026] The host control device 24 has an X-axis command section 2 and a Y-axis command section 3, as well as a reference angle generation section 4. The X-axis command section 2 and the Y-axis command section 3 generate X-axis and Y-axis position command values ​​Pc for each predetermined command distribution period T (for example, T = 1 ms). The reference angle generation section 4 receives as input the X-axis and Y-axis position command values ​​Pc from the X-axis command section 2 and the Y-axis command section 3. Furthermore, the reference angle generation section 4 uses the X-axis and Y-axis position command values ​​Pc to generate the X-axis and Y-axis reference angles θ and inputs these into the X-axis device for learning control 26 and the Y-axis device for learning control 30.

[0027] Here, the generation of the X-axis and Y-axis reference angles θ by the reference angle generation section 4 is described using Fig. 4 explained. Fig. Section 4 is an example of the case where the position command value Pc forms, for example, a closed curve L. The reference angle generation section 4 defines some position within the closed curve L, which the position command value Pc defines as its midpoint, and calculates a reference angle θ that monotonically increases or decreases from a reference point on the curve and the current machining point. For example, if the closed curve L is in the plane of the perpendicularly intersecting X and Y axes, which in Fig. As illustrated in Figure 4, when the machining process is repeated, it establishes some position P on the inside of the closed curve L as the midpoint and defines this coordinate as P(Xo, Yo). The driven element performing the machining is repeatedly caused to rotate in one direction along the closed curve L. The learning control of the angle synchronization type is executed with a predetermined sampling period, so the reference angles θ used here are also calculated for each identical sampling period.

[0028] Here, the processing point on the closed curve one sampling period before the current processing point is denoted by S(Xs, Ys), while the processing point at which the processing is currently being performed is denoted by M(Xm, Ym). It should be noted that the processing start point (origin value) on the closed curve L is taken as the reference point. The three points M, P, and S above are used to find the reference angle θn at a given time "n". The lengths PS, SM, and MP of the sides of the triangle are found using the following formulas 1, 2, and 3 (where √ represents the square root of everything in parentheses). PS=√((Xs−Xo)2+(Ys−Yo)2) SM=√((Xm−Xs)2+(Ym−Ys)2) MP=√((Xo−Xm)2+(Yo−Ym)2)

[0029] Furthermore, the quantity of change Δθ per sampling period of the found reference angle will be found from the law of cosines using the following formula 4. Δθ=arccos(MP2+PS2−SM2) / (2*MP*PS)

[0030] Furthermore, the reference angle θn, found in the sampling period "n", is calculated as the cumulative value of Δθ, which is found using formula 4 from θn=Σ(Δθ). During machining by the driven element, the driven element rotates continuously in one direction and does not rotate in the opposite direction at the midpoint, so that the found reference angle θ increases or decreases monotonically. Therefore, the reference angle θ calculated as explained above is sent from the reference angle generation section 4 to the learning control device 26 of the X-axis servo control device 18 and to the learning control device 30 of the Y-axis servo control device 20. By operating the learning control devices 26 and 30, the servo motors 12 and 14 are controlled. It should be noted that the midpoints, reference points, and machining points are also available for the closed curve L, which is shown in Fig. 2A illustrates the polygon P, which is in Fig. 2B is illustrated, and the columnar elements V1 and V2, which are shown in Fig. 2C and Fig. 2D illustrations are illustrated.

[0031] The following describes the processing sequence for the servomotor control system 1 explained above, using the flowchart provided in Fig. Figure 5 illustrates and explains. It should be noted that, to facilitate understanding of the explanation, the reference symbols of the components in the servomotor control system 1, which is shown in Figure 5, are explained. Fig. Figure 3 illustrates the process of assigning commands for machining a closed curve or polygon on perpendicularly intersecting coordinate planes (different axes with position command values ​​Pc) to the X-axis servo control 18 and the Y-axis servo control 20 (referred to below as "servo control 18 and 20") in each predetermined command distribution period T (for example, T = 1 ms).

[0032] In the next step 502, the servo control devices 18 and 20 detect the positions of the servo motors 12 and 14 or the position of the driven element (position feedback value Pf). Subsequently, in step 503, the servo control devices 18 and 20 calculate the error (position error Er) from the commands (position command values ​​Pc) and position (position feedback value Pf). The error (position error Er) is input into the X-axis and Y-axis devices for the adaptive control 26 and 30.

[0033] On the other hand, the reference angle generation section 4 on the host control device 24 defines any position on the inside of a closed curve or polygon being machined as the center (midpoint) at step 504 and calculates and finds the reference angle θ and the reference point on the lines and the current machining point at step 505. It inputs the reference angle θ that is found into the X-axis and Y-axis devices for the learning control 26 and 30.

[0034] If the error (position error Er) and the reference angle θ are entered into the X-axis and Y-axis devices for learning control 26 and 30 at step 506, these devices use the error (position error Er) and the reference angle θ to perform learning control with angle synchronization. Learning control with angle synchronization is well-known, so its explanation is omitted.

[0035] If the X-axis and Y-axis devices for learning control 26 and 30 are performing angle synchronization learning control, the first correction amount c1 for each reference angle θ is converted into the second correction amount c2 for each sampling period and output from the X-axis and Y-axis devices for learning control 26 and 30. In step 507, the servo control devices 18 and 20 add the outputs of the X-axis and Y-axis devices for learning control 26 and 30 with the error (position error Er) to generate speed commands for the servo motors 12 and 14. The servo motors 12 and 14 are controlled by these speed commands during drive operations.

[0036] It should be noted that in the embodiment described above, the reference angle generation section 4 was provided at the host control device 24, but the reference angle generation section 4 can, as in the other embodiment, be located in Fig. Figure 6 illustrates that reference angle generation sections 5 and 6 are also provided on the X-axis servo control device 18 and the Y-axis servo control device 20. The servo motor control system 1A of the embodiment shown in Fig. As illustrated in Figure 6, the configuration is the same as that of the servomotor control system 1 of the embodiment shown in Figure 6. Fig. Figure 3 illustrates this, with the exception of the reference angle generation sections 5 and 6, so that the same reference symbols are assigned to the same components and explanations are omitted.

[0037] According to the servomotor control system of the present invention, the system defines any point on the inside of a commanded closed curve, polygon, or other closed shape as the center, then calculates the angle from a reference point to the current machining point, and uses this for adaptive control of the angle synchronization type. Thus, in this case, if the period is 360 degrees, adaptive control becomes possible even if the diameter of the circle changes. According to the servomotor control system of the present invention, adaptive control of the angle synchronization type can therefore be applied, and higher precision can be achieved even when machining a shape, such as a closed curve or polygon, for which application was previously difficult.

Claims

[1] A servomotor control system (1) in a machine tool or an industrial machine, which uses coordinated operations of several axes comprising two mutually orthogonal axes (X, Y) driven by servomotors (12, 14) to machine a workpiece in the form of a closed figure with a convex surface or a columnar or conical element positioned parallel to this closed figure at an upper end and a lower end, wherein the servomotor control system (1) comprises: a host control device (24) that generates position command values ​​(Pc) for machining the workpiece at each predetermined sampling period; a servo control system (10) that uses the position command values ​​(Pc) as the basis for driving the servomotors (12, 14) of the axes to actuate a driven element that processes the workpiece; Position detectors (27, 31) that detect the positions (Pf) of the servomotors (12, 14) or a position of the driven element; a position error calculation section (35) that calculates a position error (Er) between position command values ​​(Pc) and the detected positions (Pf) of the servomotors (12, 14); a reference angle generation section (4, 5, 6) and learning control sections for learning control (26, 30), wherein the reference angle generation section (4, 5 and 6) is configured to: to designate any position within a closed figure formed by the position command value as the center point P and to define this coordinate from the origin (0,0) as P(Xo, Yo), to designate a point S, which is an editing point on the closed figure one editing period before a current editing period, and to define these coordinates as S(Xs, Ys), to designate a processing point M at which the processing is carried out during the current processing period and to define these coordinates as M(Xm, Ym), The lengths PS, SM and MP, as the sides of a triangle connecting points S, M and P, can be calculated using the following formulas: PS=((Xs−Xo)2+(Ys−Yo)2)1 / 2 SM=((Xm−Xs)2+(Ym−Ys)2)1 / 2, and MP=((Xo−Xm)2+(Yo−Ym)2)1 / 2, The quantity of change Δθ per sampling period of the reference angle θn between the two sides PS and MP can be calculated using the following formula: Δθ=arccos(MP2+PS2−SM2) / (2*MP*PS), and to calculate a reference angle θn, which increases or decreases monotonically from a reference point on the closed figure and a current processing point at a predetermined sampling period "n", as the cumulative value of the change quantity Δθ; and wherein the learning control sections (26, 30) are configured to perform a learning control of the angle synchronization type based on reference angle θn and position error (Er). [2] Servo motor control system (1) according to claim 1, wherein the position error calculation section (35) and the learning control sections (26, 30) are provided on the servo control system (10). [3] Servo motor control system (1) according to claim 1 or 2, wherein the reference angle generation section (4) is provided on the host control device (24). [4] Servo motor control system (1) according to claim 1 or 2, wherein reference angle generation sections (5, 6) are provided on the servo control system (10).

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