JP2012113430A - Drive control apparatus for servo motor with at least two feed shafts orthogonal with each other for moving table of machine tool or tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive control apparatus for a servo motor in which, during arcuate cutting of a workpiece, a cut face of a workpiece is prevented from being dug in by excessive correction under learning control.SOLUTION: A data production section 5 produces coordinate data of a circular arc having a projecting portion which is formed correspondingly to an inversion position in a driving direction of a feed shaft of a servo motor 2 when performing an arcuate operation of a table so as to eliminate digging into a cut surface of a workpiece during arcuate cutting of the workpiece. The coordinate data are sent to a servo motor drive section 3 as a position command. The servo motor drive section 3 drives the servo motor 2 by outputting to the servo motor 2 a speed command determined on the basis of a positional deviation between the position command and an actual position of the servo motor 2, and repetitively performs the arcuate operation of the table. On the basis of the position command, a learning controller 4 determines correction data avoiding digging into the cut surface in inverting the driving direction of the feed shaft of the servo motor 2.

Description

  The present invention relates to a drive control apparatus for a servo motor having at least two feed axes orthogonal to each other for moving a table or a tool of a machine tool.

  In order to process a workpiece attached to a table of a machine tool, a servo motor that drives two feed axes orthogonal to each other for moving the table is widely used. When a workpiece is cut into a circle (perfect circle or ellipse) or arc (true arc or ellipse arc) using such a servo motor, the servo motor drive control device and the servo motor or table position command and servo motor. Alternatively, the speed command or torque command is obtained based on the position deviation from the actual position of the table, the speed command or torque command is output to the servo motor at predetermined intervals, and the servo motor is driven to perform the circular or arc motion of the table. Let it be repeated.

  When repeatedly performing circular or arc cutting on a workpiece mounted on a table that moves on a plane orthogonal to the X and Y axes, for example, if the center of the circle or arc is the origin of the coordinate system, the table is positive X The quadrant changes during the circular or arc cutting by moving in the axial direction and the negative Y-axis direction, and the table moves in the negative X-axis direction and the negative Y-axis direction. In this case, regarding the movement of the table in the Y-axis direction, the servomotor drives the feed axis in the Y-axis direction to cut the workpiece so that the table moves at the previous movement speed. For movement in the direction, the table cannot be reversed immediately due to the influence of friction when the drive direction of the feed axis in the X-axis direction is reversed (when reversing from the positive X-axis direction to the negative X-axis direction). There is a delay in the movement of the table in the X-axis direction. Further, there is a delay in the movement of the table in the X-axis direction due to the backlash of the table feed screw. As a result, a protrusion (hereinafter referred to as “quadrant protrusion”) is generated on the cutting surface of the workpiece due to a delay in the movement of the table when the quadrant changes during circular or arc cutting.

  Conventionally, speed command or torque command correction data is obtained by learning control in order to reduce such quadrant projections, and table movement delays when the servo motor drive direction is reversed when performing table circular or arc motion Has been proposed (for example, Patent Document 1). By such learning control, the trajectory of the table movement becomes a trajectory close to a perfect circle or a true arc, and quadrant protrusions generated on the cutting surface of the workpiece can be reduced.

Japanese Patent No. 3805309

  When the correction data of the speed command or torque command is obtained by learning control, the quadrant projection generated on the cutting surface of the workpiece is reduced, but the perfect circle position command is input to the learning control unit, and the drive direction of the servo motor is reversed. If the correction data for the hour is obtained, the correction becomes excessive, and the cutting surface of the workpiece may bite (dent). In this case, even if a certain amount of quadrant projections can be allowed, it is not possible to meet the demand for eliminating the biting generated on the cutting surface of the workpiece.

  The object of the present invention is to prevent the cutting surface of the workpiece from biting when the workpiece is subjected to circular or arc cutting while learning control of the correction data of the speed command or torque command to reduce the quadrant projection. It is an object of the present invention to provide a drive control device for a servo motor that can be used.

  A servo motor drive control apparatus according to the present invention is a servo motor drive control apparatus having at least two feed axes orthogonal to each other for moving a table or a tool of a machine tool. Alternatively, in order to perform arc cutting, a speed command or torque command is obtained based on a positional deviation between the position command for the servo motor, table or tool and the actual position of the servo motor, table or tool, and the speed command or torque command is determined at a predetermined cycle. Output to the servo motor each time to drive the servo motor to repeat the circle or arc motion of the table or tool and at least two feeds when performing the circle or arc motion of the table or tool Reduces table or tool movement delay when reversing one drive direction of an axis Therefore, a learning control unit for obtaining correction data for speed command or torque command by learning control, and a table or tool circle or the like so that the cutting surface of the workpiece does not bite during the cutting of the workpiece circle or arc Servo motor drive unit that generates coordinate data of a circle or arc having a projection formed corresponding to the reversal position in one drive direction of at least two feed axes when performing an arc motion, and uses the coordinate data as a position command And a data generation unit to be sent out.

  Preferably, based on the circle or arc radius, the tangential speed of the table or tool during the circle or arc motion, and the difference between the circle or arc radius and the distance between the center of the circle or arc and the tip of the protrusion and the circle or arc radius A stop time calculating unit that calculates a stop time of one of the at least two feed axes at a reversal position in one drive direction of the at least two feed axes, and the data generation unit includes The servomotor drive control device according to claim 1, wherein coordinate data of a circle or an arc is generated using the stop time.

  Preferably, on the basis of the stop time of one of the at least two feed axes, the movement speed of the table or the tool before the stop of one of the at least two feed axes and after the restart of the driving is continued. It further has a moving speed calculation unit for calculating the moving speed of the table or tool after restarting one drive, and the data generation unit uses the moving speed of the table or tool after restarting one of the at least two feed axes. Generate coordinate data for a circle or arc.

  Preferably, the radius of the circle or arc, the tangential speed of the table or tool during the operation of the circle or arc, the difference between the distance between the center of the circle or arc and the tip of the projection and the radius of the circle or arc, and the projection And a shape designating unit for designating the shape of the projection based on the pattern, and the data generation unit generates coordinate data of a circle or an arc using the shape of the projection.

  According to the present invention, one of the two feed axes in the drive direction of the two feed shafts when performing the circle or arc movement of the table or tool so that the cutting surface of the workpiece does not bite during the cutting of the circle or arc of the workpiece. Coordinate data of a circle or arc having a protrusion formed corresponding to the reversal position is generated, and the coordinate data is sent to the servo motor drive unit as a position command. By generating coordinate data of a circle or arc having protrusions in this way, the trajectory of the movement of the table or tool is not a trajectory close to a true circle or true arc, but is processed when cutting a circle or arc of the workpiece. It becomes a locus of a circle or an arc having a projection formed so as to prevent biting on the cutting surface of the object. Therefore, it is possible to prevent the cutting surface of the workpiece from biting when the workpiece is subjected to circular or arc cutting while performing learning control of the correction data of the speed command or torque command in order to reduce the quadrant projection. it can.

1 is a block diagram of a first embodiment of a servo motor drive control device according to the present invention; FIG. It is a figure which shows a servomotor drive part in detail. It is a flowchart of operation | movement of 1st Embodiment of the drive control apparatus of the servomotor by this invention. It is a figure for demonstrating the position command at the time of the circular arc motion of a table. It is a figure for demonstrating the circular arc which has a projection part. It is a figure for demonstrating the position command and speed command of a table at the time of calculating a return speed. It is a block diagram of 2nd Embodiment of the drive control apparatus of the servomotor by this invention. It is a figure which shows the example of the pattern of the protrusion input into the shape designation | designated part of FIG. It is a flowchart of operation | movement of 2nd Embodiment of the drive control apparatus of the servomotor by this invention. It is a figure which shows the other example of a servomotor drive part in detail.

Embodiments of a servo motor drive control apparatus according to the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.
FIG. 1 is a block diagram of a first embodiment of a servo motor drive control apparatus according to the present invention. The servo motor drive control device 1 is a servo motor 2 that drives a feed axis in the X-axis direction and a feed axis in the Y-axis direction that are orthogonal to each other and moves a table of a machine tool (not shown) on a plane orthogonal to the X-axis and the Y-axis. Are controlled and arc cutting is repeatedly performed on a table (not shown). For this purpose, the servomotor drive control device 1 includes a servomotor drive unit 3, a learning controller 4, a data generation unit 5, a stop time calculation unit 6, and a return speed calculation unit 7.

  As will be described in detail later, the servo motor drive unit 3 is configured to cut a workpiece attached to a table (not shown) by a circular arc with a tool (not shown). Alternatively, a speed command is obtained based on a positional deviation from an actual position of a table (not shown). Further, as will be described in detail later, the servo motor drive unit 3 drives the servo motor 2 by outputting a speed command to the servo motor 2 at predetermined intervals, and repeatedly performs a circular arc operation of a table (not shown). .

  As will be described in detail later, the learning controller 4 moves the table (not shown) when reversing the drive direction of one of the feed axis in the X-axis direction and the feed axis in the Y-axis direction when performing an arc motion of the table (not shown). In order to reduce the delay, the learning control unit functions to obtain speed command correction data by learning control.

  The data generation unit 5 generates coordinate data of an arc having a protrusion, and sends the coordinate data to the servo motor drive unit 3 as a position command. In addition, such a protrusion is a feed axis in the X-axis direction when performing a circular motion of a table (not shown) so that the cutting surface of the workpiece (not shown) does not bite during arc cutting of the workpiece (not shown). It is formed corresponding to the reverse position of one drive direction of the feed axis in the Y-axis direction.

  The stop time calculation unit 6 calculates the arc radius r, the tangential speed F of a table (not shown) during the arc operation, and the difference d between the arc radius and the distance between the center of the arc and the tip of the protrusion (hereinafter, “ Is input from an external device (not shown) (for example, a computer), and based on the arc radius d, tangential velocity F, and protrusion amount d, the feed axis in the X-axis direction and the feed in the Y-axis direction are input. The stop time of one of the feed axis in the X-axis direction and the feed axis in the Y-axis direction at the reversal position in one drive direction of the shaft is calculated. The stop time calculation unit 6 outputs the calculated stop time to the data generation unit 5, and the data generation unit 5 uses the stop time when generating the arc coordinate data.

  The movement speed calculation unit 7 receives the stop time from the stop time calculation unit 6, and the movement speed of a table (not shown) before the stop of one of the X-axis direction feed axis and the Y-axis direction feed axis and after the restart of driving continues. Thus, the moving speed (return speed) of the table (not shown) after the driving of the feed axis in the X axis direction and the feed axis in the Y axis direction is resumed. Note that the table moving speed is continuous means that either the section in which the table moving speed increases or the section in which the table moving speed increases or the table moving speed is constant while the table (not shown) performs an arc motion. Means that exists. On the other hand, the table moving speed being discontinuous means that there are both a section in which the moving speed of the table increases and a section in which the table moving speed decreases while the table (not shown) performs an arc motion. The movement speed calculation unit 7 outputs the calculated movement speed to the data generation unit 5, and the data generation unit 5 uses the movement speed of a table (not shown) when generating the arc coordinate data.

  FIG. 2 is a diagram showing the servo motor drive unit in detail. As shown in FIG. 2, the servo motor drive unit 3 includes a subtracter 8, an adder 9, a position gain element 10 of a position loop, and an integration element 11.

  The subtracter 8 subtracts the feedback of the actual position of the servo motor 2 or the table (not shown) from the position command for the servo motor 2 or the table (not shown) sent from the data generation unit 5 at a predetermined sampling period to obtain a position deviation. . Further, the learning controller 4 stores the obtained position deviation, and obtains a correction amount based on the position deviation one cycle before repeatedly commanded. The adder 9 adds the position deviation and the correction amount to obtain the corrected position deviation. The position gain element 10 of the position loop multiplies the corrected position deviation by the position gain Kp to obtain a speed command, and outputs the speed command to the servo motor 2 at predetermined intervals, thereby driving the servo motor 2. Do not repeat the arc movement of the table. The integrating element 11 integrates speed feedback from a speed detector (not shown) provided in the servo motor 2 to obtain an actual position of the servo motor 2 or a table (not shown).

  The learning controller 4 has a storage unit that stores data corresponding to position deviations obtained every predetermined period during one pattern period of position commands of the same pattern repeatedly commanded to process the same shape, The position deviation obtained in the period and the data stored based on the position deviation one pattern period before are added and stored as data of the current period after the filter processing. In addition, the learning controller 4 outputs the storage data before one pattern period after performing dynamic characteristic compensation processing, and adds it to the position deviation.

  When a pattern of a predetermined section that is repeatedly commanded to process a predetermined section (in this case, an arc) in which a quadrant protrusion is generated is repeatedly executed a plurality of times while performing learning control, the position deviation converges to zero. When the position deviation converges to zero, the position deviation is corrected by the learning controller 4, and a speed command obtained by multiplying the corrected position deviation by the position gain Kp is acquired as speed command correction data. This correction data can be regarded as a speed command for obtaining high accuracy. Correcting the correction data by adding it to the speed command has the same effect as applying feedforward.

  Feed forward compensates for position control delay due to position gain by adding the differential value of the position command to the speed command and can bring the position deviation close to zero. However, the differential value of the position command is sufficient for speed control. Only when it has a proper tracking characteristic, it becomes an ideal speed command, and when the influence of backlash acting on the servo motor 2 is strong, one of the feed axis in the X-axis direction and the feed axis in the Y-axis direction of the servo motor 2 When the direction is reversed, the additional torque changes abruptly, so that sufficient speed followability cannot be obtained, and a position deviation, that is, a quadrant projection is generated.

  When learning control is applied, the speed control has sufficient follow-up characteristics and quadrant protrusions can be sufficiently suppressed, and the command speed output by applying learning control is normal feedforward control. It can be regarded as a better practical ideal speed command. The correction data acquired in this way is equal to the ideal speed command, and by correcting the speed command with the correction data at the same timing as the learning control, machining with high shape accuracy can be performed, and the cutting surface of the workpiece can be processed. The resulting quadrant projections can be reduced.

  FIG. 3 is a flowchart of the operation of the servo motor drive control apparatus according to the first embodiment of the present invention. The processing flow shown in FIG. 3 is performed by each component of the servo motor drive control device 1 executing a control program stored in a memory (not shown).

  First, in step S1, the downtime calculation unit 6 acquires the arc radius r, the tangential velocity F, and the protrusion amount d from an external device (for example, a computer) (not shown). Next, in step S2, a stop time t0 corresponding to the projection amount d is calculated.

  FIG. 4 is a diagram for explaining a position command at the time of a circular arc operation of the table. In FIG. 4, the position in the X-axis or Y-axis direction is plotted on the vertical axis, and the time is plotted on the horizontal axis. The sine wave a corresponds to a position command in the X-axis direction, and the sine wave b corresponds to a position command in the Y-axis direction. By driving the feed axis in the X-axis direction and the feed axis in the Y-axis direction of the servo motor 2 from time 0 to time T, the table (not shown) has an arc center as the origin and (−r, 0) to (0, r The arc motion is performed along the true arc section from (0, r) to (r, 0).

  FIG. 5 is a diagram for explaining an arc having a protrusion. In FIG. 5, the position of the table (not shown) in the Y-axis direction is plotted on the vertical axis, and the position of the table (not shown) in the X-axis direction is plotted on the horizontal axis. When a table (not shown) performs an arc motion along a true arc section from (−r, 0) to (0, r) with the arc center as the origin, X of the arc between points P1 and P2 in FIG. The position in the axial direction corresponds to the curve between the point X1 and the point X2 of the sine wave a in FIG. 4, and the position in the Y-axis direction of the arc between the point P1 and the point P2 in FIG. Corresponds to the curve between the points Y1 and Y2 of the sine wave b. When a table (not shown) performs an arc motion along a true arc section from (0, r) to (r, 0) with the arc center as the origin, the arc between the points P2 and P3 in FIG. The position in the X-axis direction corresponds to the curve between the point X2 and the point X3 of the sine wave a in FIG. 4, and the position in the Y-axis direction of the arc between the point P2 and the point P3 in FIG. 4 corresponds to the curve between the point Y2 and the point Y3 of the sine wave b.

  In the present embodiment, the drive direction of the feed axis in the Y-axis direction when performing the arc motion of the table (not shown) so that the cutting surface of the workpiece (not shown) does not bite during arc cutting of the workpiece (not shown). Projections are formed corresponding to the inverted positions. In FIG. 5, the protruding portion is a portion surrounded by a straight line between the point P2 and the point Q1, a straight line or a curve between the point Q1 and the point Q2, and an arc between the point P2 and the point Q2. Has the quantity d.

When the angular velocity of a table (not shown) that performs an arc motion is ω, the relational expression F = r · ω is established among the tangential velocity F, the radius r, and the angular velocity ω. Further, when the feed axis in the Y-axis direction is stopped for t0 seconds at the point P2 corresponding to the reversal position in the drive direction of the feed axis in the Y-axis direction when performing the arc motion of the table (not shown), (r + d) ² = The relational expression r ² + (r · sin ωt 0) ² is established. By solving this equation for t0, the stop time t0 with respect to the protrusion amount d can be obtained.

  Next, in step S3, the moving speed calculation unit 7 calculates the return speed V. Here, as shown in FIG. 5, a table (not shown) first performs an arc motion between the points P1 and P2, then performs a linear motion between the points P2 and Q1, and then A case where a linear motion or a curved motion is performed between the points Q1 and Q2 and an arc motion is finally performed between the points Q2 and P3 will be described.

  FIG. 6A is a diagram for explaining a table position command when the return speed is calculated. In FIG. 6A, the vertical axis plots the position in the Y-axis direction, and the horizontal axis plots time. A curve c corresponds to a position command in the Y-axis direction. In FIG. 6A, points Y1, Y2, Y3, Y4, Y5 correspond to the Y coordinates of points P1, P2, P3, Q1, Q2 in FIG. Note that the curve c is expressed by rsin ωt except for a point between the point Y2 and the point Y4 and a point Y4 and the point Y5 when the time is t.

  FIG. 6B is a diagram for explaining a table speed command when the return speed is calculated. In FIG. 6B, the speed in the Y-axis direction is plotted on the vertical axis, and the time is plotted on the horizontal axis. Curve d corresponds to a speed command in the Y-axis direction. In FIG. 6B, points dY1, dY2, DY3, DY41, dY42, DY5 correspond to points P1, P2, P3, Q1, Q1, Q2 in FIG. Note that the curve d is expressed by rωcosωt except for a point between the points dY2 and dY41, a point dY41 and the point dY42, and a point dY42 and the point dY5, where time is t.

  In order for the speed command at time t1 at point Y5 to be continuous, the curve c only has to be continuous at point Y5, so the straight line between point Y4 and point Y5, point Y5 and point The speed V is determined so that the differential coefficient at the boundary point Y5 with Y3 matches.

  The tangent at the point Y5 is represented by the relational expression y-rsin ωt1 = rωcos ωt1 (t−t1). Since this tangent line passes through the point Y4, if y = r and t = π / 2ω + t0 are substituted into this relational expression, r−rsinωt1 = rωcosωt1 (π / 2ω + t0−t1), that is, 1−sinωt1 = ωcosωt1 (π / 2ω + t0−t1) ) Is established. By solving this relational expression for t1 and setting the speed V = rωcosωt1, the speed command at the point dY5 becomes continuous.

  Next, in step S4, the data generation unit 5 generates the coordinate data of the arc having the projection using the stop time t0 and the return speed V, and sends the coordinate data to the servo motor drive unit 3 as a position command.

  Next, in step 5, the servo motor drive unit 3 sets the value C of a counter (not shown) to zero, and in step S6, the servo motor drive unit 3 detects the generated position command and the actual value of the servo motor 2 or a table (not shown). A speed command is obtained based on a position deviation from the position, and the speed command is output to the servo motor 2 at predetermined intervals, thereby driving the servo motor 2 to perform a circular motion of a table (not shown).

  Next, in step S7, the servo motor drive unit 3 determines whether or not a counter value C (not shown) has reached the number of repetitions of the arc motion. If the number of repetitions has not been reached, the servo motor drive unit 3 increments the value C of a counter (not shown) by 1 in step S8, and returns to step S6. On the other hand, when the number of repetitions has been reached, in step S9, the learning controller 4 calculates correction data and ends this routine. The correction data calculated by the learning controller 4 in step S9 is output to the servo motor 2 as a speed command value for driving the servo motor 2.

  The position command generated in step S4, that is, the position command corresponding to the arc shape having the protruding portion is different from the position command generated using the coordinate data of the true arc, that is, the arc having no protruding portion. In addition, the correction data calculated by the learning controller 4 in step S9 has a correction amount smaller than the correction data calculated based on the position command generated using the coordinate data of the arc having no protrusion. Therefore, the trajectory of the arc motion performed in step S6 is an arc trajectory having a protrusion that prevents the cutting surface of the workpiece from biting during the arc cutting of the workpiece.

  According to the present embodiment, at the reversal position of the feed axis drive direction in the Y axis direction when performing the arc motion of the table (not shown) so that the cutting surface of the workpiece does not bite during the arc cutting of the workpiece. Coordinate data of an arc having a correspondingly formed protrusion is generated, and the coordinate data is sent to the servo motor drive unit 3 as a position command. By generating the coordinate data of the arc having the protrusions in this way, the movement trajectory of the table (not shown) is not a trajectory close to the arc, and the cutting surface of the work piece is bitten during the arc cutting of the work piece. The locus of a circular arc having a protrusion formed so as to disappear. Therefore, it is possible to prevent the cutting surface of the workpiece from biting when performing circular arc cutting of the workpiece while performing learning control of the correction data of the speed command in order to reduce the quadrant projection.

  FIG. 7 is a block diagram of a second embodiment of a servo motor drive control apparatus according to the present invention. In FIG. 7, the servo motor drive control device 21 includes a servo motor drive unit 3, a learning controller 4, a data generation unit 22, and a shape designation unit 23. The servo motor drive unit 3 and the learning controller 4 have the same configuration as the servo motor drive unit 3 and the learning controller 4 of the servo motor drive control device 1 according to the first embodiment shown in FIG. Is omitted.

  The data generation unit 22 receives radius r, tangential velocity F, and projection shape data instead of the stop time and return velocity, and uses the radius r, tangential velocity F, and projection shape data. To generate arc coordinate data.

  The shape designation unit 23 receives the projection amount d and the projection pattern, designates the projection shape based on the projection amount d and the projection pattern, and outputs the projection shape data to the data generation unit 22. The pattern of protrusions can be, for example, a triangular wave shape as shown in FIG. 8A or a square wave shape as shown in FIG. 8B.

  FIG. 9 is a flowchart of the operation of the second embodiment of the servo motor drive control apparatus according to the present invention. The processing flow shown in FIG. 2 is performed by each component of the servo motor drive control device 21 executing a control program stored in a memory (not shown).

  In this case, after calculating the stop time in step S2, in step S11, the shape designating unit 23 designates the shape of the projection based on the projection amount d and the pattern of the projection, and generates data on the shape of the projection. Next, in step S12, the data generation unit 22 generates arc coordinate data using the radius r, the tangential velocity F, and the projection shape data, and the process proceeds to step S5.

  Even when the coordinate data of the arc is generated using the data of the radius r, the tangential velocity F, and the shape of the protrusion as in the present embodiment, learning control of the correction data of the speed command is performed in order to reduce the quadrant protrusion. However, it is possible to prevent the cut surface of the workpiece from biting when the workpiece is subjected to arc cutting.

  The present invention is not limited to the above-described embodiment, and many changes and modifications can be made. For example, in the above embodiment, the case where the workpiece is subjected to arc cutting has been described, but the present invention can also be applied to the case of circular cutting.

  Further, in the above embodiment, the case where the servo motor having two feed axes orthogonal to each other for moving the table has been described, but the tool may be moved instead of the table, and three or more feed axes may be used. The present invention can also be applied to cases where

  Further, even when the stop time calculation unit 6 and the movement speed calculation unit 7 of the drive control apparatus 1 for the servo motor shown in FIG. 1 are omitted, the radius r, the tangential speed F, and the protrusion amount d are directly input to the data generation unit 5. The cutting surface of the workpiece can be prevented from biting when the workpiece is circularly cut while performing learning control of the correction data of the speed command in order to reduce the quadrant projection.

  In the above embodiment, the case where the drive direction of the feed axis in the Y-axis direction is reversed has been described. However, the present invention can also be applied to the case where the drive direction of the feed axis in the X-axis direction is reversed.

  Furthermore, although the case where the speed command is output to the servo motor 2 has been described in the above embodiment, a torque command can be output to the servo motor 2 instead of the speed command. FIG. 10 is a diagram illustrating another example of the servo motor drive unit in detail. In FIG. 10, a servo motor drive unit 31 is used instead of the servo motor drive unit 3 of FIG. 1 or FIG. 7, and a subtracter 8, an adder 9, a position gain element 10 of a position loop, and an integration element 11 And a subtractor 12 and a speed controller 13. The subtractor 8, the adder 9, the position gain element 10 and the integration element 11 of the position loop are the subtracter 8, the adder 9, the position gain element 10 and the integration element 11 of the servo motor driving unit 3 shown in FIG. Since they have the same configuration as those in FIG.

  The subtracter 12 subtracts a speed feedback from a speed detector (not shown) provided in the servo motor 2 from the speed command from the position gain element 10 of the position loop to obtain a speed deviation.

  The speed controller 13 performs PI (proportional integration) control or the like on the speed deviation to obtain a torque command and outputs it to the servo motor 2. The torque command output to the servo motor 2 in this manner is also used as torque command correction data.

1, 21 Servo motor drive control device 2 Servo motor 3, 31 Servo motor drive unit 4 Learning controller 5, 22 Data generation unit 6 Stop time calculation unit 7 Movement speed calculation unit 8, 12 Subtractor 9 Adder 10 Position loop Position gain element 11 Integration element 13 Speed controller 23 Shape specification part

Claims (4)

In a drive control device for a servo motor having at least two feed axes orthogonal to each other for moving a table or tool of a machine tool,
The position of the servo motor, the table or the tool and the actual position of the servo motor, the table or the tool to cut the workpiece attached to the table with the tool. A speed command or a torque command is obtained based on the deviation, and the speed command or the torque command is output to the servo motor at predetermined intervals to drive the servo motor to perform a circular or arc motion of the table or the tool. Servo motor drive unit that repeatedly performs,
In order to reduce the movement delay of the table or the tool when reversing the driving direction of one of the at least two feed axes when performing the circular or arc motion of the table or the tool, the speed command or the torque A learning control unit for obtaining correction data of the command by learning control;
One of the at least two feed axes in the drive direction of the table or the tool when performing a circle or arc movement of the table or the tool so that the cutting surface of the workpiece does not bite during the circle or arc cutting of the workpiece. A data generation unit that generates coordinate data of a circle or an arc having a protrusion formed corresponding to the reversal position, and sends the coordinate data to the servo motor drive unit as the position command;
A drive control device for a servo motor, comprising:   Based on the circle or arc radius, the tangential speed of the table or the tool during the circle or arc motion, and the difference between the circle or arc radius and the distance between the center of the circle or arc and the tip of the protrusion A stop time calculating unit that calculates a stop time of one of the at least two feed axes at a reversal position in one drive direction of the at least two feed axes, and the data generation unit includes the at least two The servo motor drive control device according to claim 1, wherein coordinate data of the circle or arc is generated using one stop time of the feed shaft.   Based on one stop time of the at least two feed axes, the at least two feed axes so that the moving speed of the table or the tool before the stop of one of the at least two feed axes and after the restart of driving is continuous. And a movement speed calculation unit for calculating a movement speed of the table or the tool after resumption of driving, and the data generation unit includes the table or the table after resumption of driving of one of the at least two feed axes. The servomotor drive control device according to claim 2, wherein coordinate data of the circle or arc is generated using a moving speed of a tool.   A circle or arc radius, a tangential speed of the table or the tool during the circle or arc motion, a difference between the center of the circle or arc and the tip of the protrusion and the circle or arc radius, and A shape designating unit for designating a shape of the projection based on a pattern of the projection, and the data generation unit generates coordinate data of the circle or arc using the shape of the projection. The drive control apparatus of the servomotor of 1.

Images