JP2023051255A - Controller and speed control method - Google Patents

Abstract

To appropriately control a table unit.SOLUTION: A numerical controller 1 includes a speed increase-decrease unit that increases or decreases a speed at which a table unit having plural components juxtaposed in one direction rotates about a rotation axis intersecting the one direction includes: a storage unit that stores a reference inertia, reference unbalanced load, and reference time constant; and a time constant arithmetic unit 205 that computes a time constant of the speed increase-decrease unit on the basis of the unbalanced load and inertia acquired from feedback information concerning the table unit according to a rotation angle of the table unit, and arithmetic elements including the reference inertia, reference unbalanced load, and reference time constant.SELECTED DRAWING: Figure 6

Description

The present invention relates to a controller and a speed control method.

Patent Document 1 discloses that when determining a command for driving a motor of a machine tool, the command is determined based on highly accurate parameters that consider at least the influence of the unbalanced load of a work holding portion, and the machine tool is operated according to the determined command. It discloses controlling.

JP 2020-181424 A

For example, in the case of a table unit that includes a holder that holds a workpiece and a drive section that rotates the holder, the direction intersecting the output shaft (C-axis) of the drive section, that is, the direction between the holder and the drive section When the base unit rotates around a rotation axis (A axis) extending in a direction that intersects with the side-by-side arrangement direction, there is a possibility that an unbalanced load may occur. The offset load varies according to the rotation angle of the stand unit. Moreover, the unbalanced load varies depending on the weight of the work. Therefore, when controlling the motor that drives the base unit to rotate about the rotation axis, proper control cannot be performed unless such variations in the unbalanced load are taken into consideration. However, the machine tool of Patent Document 1 as described above does not consider such a problem.

The present invention has been made in view of such circumstances, and its object is to provide a table unit having a plurality of parts including a holding table for holding a workpiece, which intersects the direction in which the plurality of parts are arranged side by side. To provide a control device and a speed control method capable of performing more appropriate control when rotating around a rotating shaft extending in a direction.

The control device according to the present invention includes a speed control unit for controlling the speed of rotation of a table unit having a plurality of parts arranged side by side in one direction, including a workpiece holding table, around a rotation axis intersecting the one direction. A control device comprising: a storage unit storing a reference inertia, a reference unbalanced load, and a reference time constant; and an obtained unbalanced load and an obtained inertia obtained according to the rotation angle of the base unit from feedback information about the base unit. and a calculation unit for calculating the time constant of the speed adjuster based on calculation elements including the reference inertia, the reference unbalanced load, and the reference time constant.

In the present invention, the obtained unbalanced load and the obtained inertia obtained from the feedback information about the base unit and the reference inertia, the reference unbalanced load, the reference time constant, etc. stored in the storage unit are used according to the rotation angle of the base unit. to calculate the time constant of the speed adjuster. Therefore, the base unit can be controlled more appropriately.

In the control device according to the present invention, the speed adjustment section has a moving average filter that limits the maximum acceleration during acceleration/deceleration of the base unit using the time constant calculated by the calculation section.

In the present invention, when the moving average filter limits the maximum acceleration during speed acceleration/deceleration of the platform unit, the time constant calculated by the calculation unit reflecting the fluctuation of the unbalanced load and the inertia of the workpiece is used. Rotation of the base unit can be better controlled.

In the control device according to the present invention, the speed adjuster has a plurality of moving average filters including the moving average filter.

In the present invention, the speed adjuster has a plurality of moving average filters in addition to the moving average filter described above, and these plurality of moving average filters are fixed values. Therefore, a constant filter effect can be obtained regardless of the usage conditions.

In the control device according to the present invention, the base unit has the holding base arranged at one end thereof, and includes other parts heavier than the holding base, and the rotating shaft is unevenly distributed near the one end of the base unit.

In the present invention, the rotating shaft of the table unit is unevenly distributed near one end of the table unit. A time constant reflecting changes in load and work inertia is calculated, and the calculated time coefficient is used to appropriately control the rotation of the base unit.

In the control device according to the present invention, the reference inertia and the reference unbalanced load are inertia and unbalanced load when the unbalanced load of the base unit is maximum.

In the present invention, the reference inertia and the reference unbalanced load used by the calculator when calculating the time constant are the inertia and the unbalanced load under the reference condition that the unbalanced load of the platform unit is maximum. Therefore, if only the reference condition is tested and the reference variable is determined, the optimum time constant under all conditions can be obtained.

In the control device according to the present invention, the calculation element includes the rotation range of the base unit.

In the present invention, the calculation section further uses the rotation range of the base unit as a calculation element used when calculating the time constant. Therefore, the rotation of the base unit can be controlled more appropriately.

A speed control method according to the present invention is a speed control method for controlling the speed at which a table unit having a plurality of parts arranged side by side in one direction, including a work holding table, rotates around a rotation axis that intersects with the one direction. stores the reference inertia, the reference unbalanced load, and the reference time constant, acquires the unbalanced load and the inertia according to the rotation angle of the base unit from the feedback information on the base unit, A time constant used for controlling the speed is calculated based on a calculation element including the stored contents.

According to the present invention, the unbalanced load and inertia are obtained from the feedback information about the base unit according to the rotation angle of the base unit, and the obtained unbalanced load and inertia are combined with the already stored reference inertia, reference unbalanced load, The time constant of the speed adjuster is calculated using the reference time constant or the like. Therefore, the base unit can be controlled more appropriately.

According to the present invention, it is possible to perform more appropriate control when a table unit having a plurality of parts including a holding table for holding a work rotates around a rotation axis extending in a direction intersecting the direction in which the plurality of parts are arranged side by side. .

1 is a schematic perspective view of a machine tool according to Embodiment 1. FIG. FIG. 2 is a partial perspective view of a machine tool with a part omitted; It is an enlarged view which expands and shows the base unit of a machine tool. It is an illustration figure explaining rotation of a base unit. 1 is a block diagram showing the configuration of a main part of a numerical controller for a machine tool; FIG. It is a block diagram explaining the structure of the control part of a machine tool. FIG. 10 is a flow chart for explaining time constant update processing by a control unit; FIG. FIG. 7 is a block diagram illustrating the configuration of a control unit of the machine tool of Embodiment 2; 4 is a flowchart for explaining calculation processing of a time constant by a control unit;

(Embodiment 1)
Hereinafter, a case where a control device and a speed control method according to an embodiment of the present invention are applied to a machine tool will be described in detail with reference to the drawings.
FIG. 1 is a schematic perspective view of a machine tool 100 according to Embodiment 1, and FIG. 2 is a partial perspective view with a part of the machine tool 100 omitted. In the following description, up/down, left/right, and front/rear directions indicated by arrows in the drawings are used.

The machine tool 100 includes a base 10, an X-direction moving device 21, a Y-direction moving device 20, a Z-direction moving device 23, a vertical column 22, a spindle head 25, a table unit 30, and the like. The machine tool 100 holds a work on a base unit 30 and processes the work with a tool 26 attached to the lower end of a vertically extending main shaft 28 . The tool 26 is detachably attached to the lower end of the spindle 28 and can be replaced by a tool changer (not shown).

A spindle head 25 including a spindle 28 is movable in the X, Y and Z directions. Hereinafter, the X-axis, Y-axis, and Z-axis indicate the moving directions of the spindle head 25 . In the machine tool 100, the workpiece can rotate around axes parallel to the X, Y, and Z axes. Hereinafter, the rotation axes of the work will be referred to as the A-axis (rotational axis), B-axis, and C-axis corresponding to the X-axis, Y-axis, and Z-axis, respectively. However, the axial direction of the C-axis of the machine tool 100 changes according to the rotation of the A-axis.

The base 10 includes a frame 11, a spindle base 13, a pair of work bases 14, and the like. The mount 11 has a substantially rectangular parallelepiped shape elongated in the front-rear direction. The spindle base 13 has a substantially rectangular parallelepiped shape elongated in the front-rear direction, and is arranged at the rear portion of the mount 11 . The spindle base 13 supports an X-direction moving device 21 and a Y-direction moving device 20 . The X-direction moving device 21 drives the vertical column 22 in the X-direction. The Y-direction moving device 20 drives the vertical column 22 in the Y-direction.

A pair of work bases 14 are arranged on the left and right sides of the front portion of the mount 11, respectively. Each work base 14 has a substantially flat rectangular parallelepiped shape, and is arranged to face each other so that the thickness direction is the left-right direction. Each work base 14 has a notch in the center of the lower long side. A stand unit 30 is arranged between the pair of work bases 14 . A pair of work bases 14 supports a base unit 30 rotatably around the A axis.

FIG. 3 is an enlarged view showing the base unit 30 of the machine tool 100 in an enlarged manner.
The table unit 30 includes a holding table 33 that holds a workpiece, a table section 32, a rotation driving section 31 (other parts) that rotationally drives the holding table 33, and the like. The holding base 33, the base portion 32, and the rotation driving portion 31 are arranged side by side on the same axis. In the direction in which the holding base 33, the base portion 32, and the rotation driving portion 31 are arranged side by side (hereinafter, referred to as the direction in which the base unit 30 is arranged side by side), the holding base 33 is arranged at one end, and the rotation driving portion 31 is arranged at the other end. , and the rotation driving portion 31, a base portion 32 is interposed therebetween. The base portion 32 has a rectangular plate shape and has a through hole in the center. The holding base 33 has a cylindrical shape and fits inside the through hole of the base portion 32 , and the upper end portion of the holding base 33 protrudes from the upper surface of the base portion 32 .

The rotary drive unit 31 rotates the holding base 33 about the direction in which the base units 30 are arranged side by side. In FIG. 3, the side-by-side direction of the base units 30 is the vertical direction, that is, the C-axis direction. The weight of the rotary drive part 31 far exceeds the base part 32 and the holding table 33 , and the rotary drive part 31 occupies most of the base unit 30 .

Each work base 14 has a through-hole 142 penetrating in the thickness direction in a substantially central portion, and has a support shaft 141 for rotatably supporting the base unit 30 . The support shaft 141 has a cylindrical shape and is slidably fitted in the through hole 142 . A connecting portion 34 connects one end of the support shaft 141 to the base unit 30 . The connecting portion 34 has a front-rear dimension that extends toward the base portion 32 and a vertical dimension that decreases, and has a trapezoidal notch in a plan view on its upper surface.

As described above, since the support shaft 141 is slidably fitted in the through hole 142 , the base unit 30 rotates around the A axis passing through the axis of the support shaft 141 . The A-axis passes near the upper end of the base unit 30, that is, slightly above the upper surface of the holding base 33, and is biased toward one end in the side-by-side arrangement direction of the base unit 30. Therefore, when the base unit 30 rotates around the A axis, an unbalanced load is generated.

4A and 4B are illustrative diagrams for explaining the rotation of the base unit 30. FIG. FIG. 4A shows the case where the A-axis angle is 0°, and FIG. 4B shows the case where the angle is 90°. When the A-axis angle is 0°, the rotation axis of the holding table 33 is vertical and the holding table 33 is positioned upward. As described above, since the A-axis is biased toward one end of the platform unit 30, the eccentric load is minimal at the position in FIG. is the maximum.

The vertical column 22 has a Z-direction moving device 23 on its front surface. The Z-direction moving device 23 drives the spindle head 25 vertically. A spindle head 25 rotatably accommodates a spindle 28 . The spindle 28 is connected to a spindle motor 27 provided at the upper end of the spindle head 25 . The main shaft 28 is driven by a main shaft motor 27 to rotate about its axis, and a tool 26 attached to the lower end of the main shaft 28 rotates. The tool 26 cuts the workpiece held on the base unit 30 .

The machine tool 100 has a numerical controller 1 that controls execution of cutting. FIG. 5 is a block diagram showing the main configuration of the numerical controller 1 of the machine tool 100. As shown in FIG.
The numerical controller 1 includes a control section 2, a ROM 3, a RAM 4, a storage section 5, an I/O (input/output section) 6, and drive circuits 71 to 76 corresponding to each axis. The control section 2, ROM 3, RAM 4 and storage section 5 are connected to drive circuits 71-76 via I/O6. Further, the I/O 6 inputs and outputs various signals between the drive circuits 71 to 76, the encoders 91 to 96 described later, the control section 2, the ROM 3, the RAM 4, the storage section 5, the operation section 7, and the display section 8. . The storage unit 5 is a rewritable storage medium such as EPROM, EEPROM, flash memory, or the like.

The control unit 2 includes a CPU and the like, and controls operations of the machine tool 100 . The ROM 3 stores control programs and the like for executing various processing related to cutting. The RAM 4 stores various data generated during execution of various processes. A storage unit 5 stores an NC program, a reference inertia, a reference unbalanced load, a reference time constant, and the like, which will be described later.

The machine tool 100 includes an X-axis motor 81, a Y-axis motor 82, and a Z-axis motor 83 that drive the X-direction moving device 21, the Y-direction moving device 20, and the Z-direction moving device 23, respectively, and the holding base 33 around the C-axis. It has a C-axis motor 84 that rotates, an A-axis motor 85 that rotates the base unit 30 around the A-axis, and a spindle motor 86 that rotates the main shaft 28 . The machine tool 100 also includes encoders corresponding to the X-axis motor 81, the Y-axis motor 82, the Z-axis motor 83, the C-axis motor 84, the A-axis motor 85, and the spindle motor 86 (hereinafter also referred to as motors 81 to 86). 91-96. Motors 81 to 86 are all servo motors.

Drive circuits 71 to 76 correspond to motors 81 to 86, respectively, and output pulse signals to motors 81 to 86 based on commands output from control unit 2. FIG. Encoders 91-96 detect the rotational positions of corresponding motors 81-86 and feed back the detected signals to drive circuits 71-76 and I/O6. The encoders 91 to 96 are general absolute value encoders, and are position sensors that detect and output the absolute position of the rotational position.

The operation unit 7 receives an instruction input by a user's operation, and the display unit 8 displays information to be notified to the user.

As described above, the A-axis is biased toward one end in the side-by-side arrangement direction of the stand unit 30, and when the stand unit 30 rotates around the A-axis, an unbalanced load is generated. direction) fluctuates depending on the angle formed with the vertical direction. Furthermore, the inertia also fluctuates depending on the weight of the work held by the base unit 30 . When controlling the A-axis motor 85, the torque of the A-axis motor 85 will be insufficient or excessive and will not be allowed unless the variations in the unbalanced load of the table unit 30 and the variations in the inertia of the workpiece are taken into consideration. There is a risk of exceeding the range. Machine tool 100 can address this problem.

FIG. 6 is a block diagram for explaining the configuration of the control unit 2 of the machine tool 100. As shown in FIG. For convenience, FIG. 6 shows only the relationship between the control section 2 and the drive circuit 75. As shown in FIG. The control of the A-axis motor 85 by the controller 2 will be described below.

The control unit 2 has a speed adjustment unit 201 , a time constant calculation unit 205 , and an inertia/unbalanced load acquisition unit 206 .
The speed adjuster 201 receives the time-series change (waveform) of the speed of the A-axis motor 85 , adjusts the speed waveform, and outputs it to the drive circuit 75 . The speed adjuster 201 adjusts the waveform of the speed in accordance with the weight of the work held by the base unit 30 and variations in the unbalanced load of the base unit 30 .

The speed adjuster 201 has a first filter 202, a second filter 203, and a third filter 204 that adjust and smooth the waveform of speed. The first to third filters 202-204 are moving average filters. The first filter 202 is a filter for limiting the maximum acceleration during acceleration/deceleration, and the second filter 203 and third filter 204 are low-pass filters for suppressing resonance of the shaft. The time constant of the first filter 202 (hereinafter referred to as t1) varies according to the weight of the workpiece held by the base unit 30, the time constant of the second filter 203 (hereinafter referred to as t2), the time constant of the third filter 204 (hereinafter referred to as , t3) are fixed values.

The inertia/unbalanced load acquisition unit 206 acquires the unbalanced load of the base unit 30 during operation and the inertia of the workpiece based on the feedback information from the encoder 95 . A method for the inertia/unbalanced load acquisition unit 206 to acquire the unbalanced load and inertia will be described.

An unbalanced load (Tw) is defined as "F _θ sin(θ)" (Formula 1). F _θ is an unbalanced load coefficient, and θ is an angle formed by the direction in which the stand units 30 are arranged side by side and the vertical direction. Tw is minimum in FIG. 4A (θ is 0°), and Tw is maximum in FIG. 4B (θ is 90°).

Inertia (J) is defined as "Jθ″=uf" (Formula 2). θ″ indicates the two-time time differentiation of the angle θ, u is the torque output by the drive circuit 75 to the A-axis motor 85, and is a measured value obtained from the drive circuit 75. f satisfies the following equation.
f=F _θ sin(θ)+F _c sign(θ′)+Dθ′ (Formula 3)
In Equation 3, .theta.' denotes the one time derivative of the angle .theta., _Fc is the Coulomb friction for the platform unit 30, and D is the viscous friction coefficient for the platform unit 30.

The inertia/unbalanced load acquisition unit 206 acquires the unbalanced load (Tw) and inertia (J) from equations 1 to 3 using the rotational position (angle θ) of the A-axis motor 85 included in the feedback information from the encoder 95. . Hereinafter, the inertia (J) and the unbalanced load (Tw) obtained by the inertia/unbalanced load obtaining unit 206 are referred to as the obtained inertia J and the obtained unbalanced load Tw, respectively.

The time constant calculator 205 calculates the time constant t1 based on the acquired unbalanced load Tw, the acquired inertia J, the reference inertia J _b , the reference unbalanced load Tw _b and the reference time constant t _b . The reference inertia J _b , the reference unbalanced load Tw _b , and the reference time constant t _b are values stored in the storage unit 5 as defaults. A method for calculating the time constant t1 by the time constant calculator 205 will be described below.

In rotational motion, torque is the product of angular acceleration and inertia, so when Tw is maximum, that is, when θ is 90° (see FIG. 4B), it can be estimated that the following relationship holds.
a _maxb = (Tm-|Tw _b |)/J _b (Formula 4)
a _maxb is the angular acceleration, and Tm is the maximum torque of the A-axis motor 85 .

In this case, the reference time constant t _b that is inversely proportional to a _maxb can be expressed as follows.
t _b = V _max /a _maxb (Formula 5)
V _max is the maximum angular velocity.

From Equations 4 and 5, the angular acceleration (a' _max ) during calculation and the time constant t1 to be obtained can be expressed by the following equations.
a' _max = (Tm-|Tw|)/ J (Formula 6)
t1= _Vmax / _a'max (Formula 7)
Tw and J are the obtained unbalanced load Tw and the obtained inertia J as described above.

Substituting Formula 6 for a' _max in Formula 7,
t1=(JV _max )/(Tm−|Tw|) (equation 8).
Rewriting Equation 4 for Tm, Tm=J _b a _maxb +|Tw _b |, and substituting this for Tm in Equation 8, we get
t1=(JV _max )/(J _b a _{max b} +|Tw _b |−|Tw|) (Formula 9).
Rewriting Equation 5 with respect to a _maxb yields a _maxb =V _max /t _b , and substituting this for a _maxb in Equation 9 yields the following equation.
t1=Jt _b / {J _b + t _b (|Tw _b |−|Tw|)/V _max } (Formula 10)

The time constant computing unit 205 computes the time constant t1 using Equation 10, and updates the reference time constant _tb stored in the storage unit 5 to the computed time constant t1. Thereafter, the speed adjuster 201 uses the updated time constant t1 to adjust and smooth the waveform of the speed of the A-axis motor 85 output to the drive circuit 75 .

FIG. 7 is a flowchart for explaining update processing of the time constant t1 by the control unit 2. As shown in FIG.
When the A-axis motor 85 is driven, the control unit 2 monitors the inertia/unbalanced load acquisition unit 206 to determine whether the inertia/unbalanced load acquisition unit 206 acquires the acquired inertia J and the acquired unbalanced load Tw. (step S101).

In the above example, the inertia/unbalanced load acquiring unit 206 calculates the acquired inertia J and the acquired unbalanced load Tw using Equations 1 to 3, but the present invention is not limited to this. The user operates the operation unit 7 to input the acquired inertia J and the acquired unbalanced load Tw, and the inertia/unbalanced load acquisition unit 206 acquires the acquired inertia J and the acquired unbalanced load Tw via the operation unit 7. Also good.

If the control unit 2 determines that the inertia/unbalanced load acquiring unit 206 has not acquired the acquired inertia J and the acquired unbalanced load Tw (step S101: NO), it repeats the determination. When the control unit 2 determines that the inertia/uneven load acquisition unit 206 has acquired the acquired inertia J and the acquired unbalanced load Tw (step S101: YES), the time constant calculation unit 205 calculates the time constant t1 using Equation 10. Calculate (step S102).

When the calculation of the time constant t1 by the time constant calculator 205 is completed, the controller 2 determines whether or not the A-axis motor 85 is in operation (step S103). If the control unit 2 determines that the A-axis motor 85 is in operation (step S103: YES), it repeats the determination. When the control unit 2 determines that the A-axis motor 85 is not in operation (step S103: NO), it updates the reference time constant _tb stored in the storage unit 5 to the calculated time constant t1 (step S104).

As described above, the machine tool 100 of the first embodiment controls the A-axis motor 85 by reflecting changes in the unbalanced load of the table unit 30 and changes in the inertia of the workpiece, so that the torque of the A-axis motor 85 is insufficient. Or, it can be prevented in advance from exceeding the allowable range due to excess.

Since the time constant t2 of the second filter 203 and the time constant t3 of the third filter 204 are fixed values as described above, the machine tool 100 can obtain a constant filter effect regardless of the conditions of use.

As described above, the machine tool 100 uses the case where θ is 90° as a reference condition, and calculates the time constant t1 using the inertia and unbalanced load at this time. Therefore, if only the reference condition is tested and the reference variable is determined, the optimum time constant under all conditions can be obtained.

(Embodiment 2)
FIG. 8 is a block diagram illustrating the configuration of the control section 2 of the machine tool 100 of Embodiment 2. As shown in FIG. For convenience, FIG. 8 shows only the relationship between the control section 2 and the driving circuit 75. As shown in FIG. The control of the A-axis motor 85 by the controller 2 will be described below.

As in the first embodiment, the control unit 2 has a speed adjustment unit 201 , a time constant calculation unit 205 , and an inertia/unbalanced load acquisition unit 206 . The speed adjuster 201 has a first filter 202, a second filter 203, and a third filter 204 that adjust and smooth the waveform of speed. The speed adjusting unit 201 and the inertia/unbalanced load acquiring unit 206 are the same as those in the first embodiment, and the description thereof is omitted.

In Embodiment 2, the controller 2 further has a positioning command generator 207 . The positioning command generation unit 207 generates a command for determining the position of the base unit 30 during so-called fast feed based on the NC program stored in the storage unit 5 . Rapid traverse refers to moving the tool before and after machining, that is, moving the tool when it is not in contact with the workpiece.

For example, the positioning command generator 207 generates a velocity waveform to be output to the drive circuit 75 and generates the rotation start angle and rotation end angle of the A-axis motor 85 . The positioning command generator 207 outputs the velocity waveform to the velocity adjuster 201 , and outputs the rotation start point angle and the rotation end point angle to the time constant calculator 205 .

In the second embodiment, the time constant calculator 205 calculates the rotation start angle from the positioning command generator 207 in addition to the acquired unbalanced load Tw, the acquired inertia J, the reference inertia _{Jb ,} the reference unbalanced load Twb, and the reference time constant _tb . and the rotation end point angle, the time constant t1 is calculated.

In the second embodiment, the time constant calculator 205 uses Equation 11 below to calculate the time constant t1.
t1= _Jtb /{ _Jb + _tb (| _Twb |-k|Tw|)/ _Vmax } (Equation 11)
In Equation 11, k is defined by the following equation.
k＝max{|sinθ|,θmin<θ<θmax}
θmin: Rotation start angle, θmax: Rotation start angle

That is, the time constant calculator 205 of the second embodiment reflects the rotation start point angle and the rotation end point angle from the positioning command generator 207 in the calculation of the time constant t1. As a result, when the unbalanced load is not large, the rotation of the base unit 30 about the A-axis can be controlled more appropriately, such as by increasing the acceleration due to the extra torque of the A-axis.

The time constant calculator 205 uses Equation 11 to calculate the time constant t1, and the speed adjuster 201 uses the calculated time constant t1 to generate the waveform of the speed of the A-axis motor 85 that is output to the drive circuit 75. to smooth it out.

FIG. 9 is a flow chart for explaining calculation processing of the time constant t1 by the control unit 2. As shown in FIG.
The control unit 2 reads one line of the NC program stored in the storage unit 5 (step S201), and determines whether or not the command of the read program is a fast-forward command (step S202). If the controller 2 determines that the command of the read program is not the fast-forward command (step S202: NO), it executes processing corresponding to the command of the program (step S207). Henceforth, a process progresses to step S206.

When the control unit 2 determines that the read program command is a fast-forward command (step S202: YES), the positioning command generation unit 207 determines the rotation start angle and the rotation end point of the A-axis motor 85 according to the program command. An angle is generated, and the time constant calculator 205 acquires the rotation start point angle and the rotation end point angle from the positioning command generator 207 (step S203).

The time constant calculator 205 calculates the time constant t1 using Equation 11 (step S204). The speed adjuster 201 uses the time constant t1 calculated by the time constant calculator 205 to adjust the waveform of the speed of the A-axis motor 85 output to the drive circuit 75 to adjust the speed (step S205).

After the processing of step S205 or step S207 is completed, the control unit 2 determines whether or not the execution of the instructions of all programs has been completed (step S206). If the control unit 2 determines that the execution of all program commands has not ended (step S206: NO), the process returns to step S201 and reads the next line from the NC program stored in the storage unit 5. If the control unit 2 determines that the execution of the commands of all programs has ended (step S206: YES), it ends the process.

The same reference numerals are assigned to the same parts as in the first embodiment, and detailed description thereof will be omitted.

In the above description, the case where the base unit 30 rotates around the A axis has been described as an example, but the present invention is not limited to this. It is also applicable when the base unit 30 rotates around the B-axis perpendicular to the A-axis and the C-axis.

1 Numerical Control Device 5 Storage Part 30 Unit 31 Rotation Drive Part 33 Holding Base 100 Machine Tool 201 Speed Controlling Part 202 First Filter 203 Second Filter 204 Third Filter 205 Time Constant Calculating Part 206 Inertia/Uneven Load Acquiring Part 2 Control Department

Claims (7)

A control device comprising a speed adjuster that adjusts the speed of rotation of a table unit having a plurality of parts arranged side by side in one direction, including a workpiece holding table, around a rotation axis that intersects with the one direction,
a storage unit that stores a reference inertia, a reference unbalanced load, and a reference time constant;
The speed acceleration/deceleration is based on computational elements including the obtained unbalanced load and the obtained inertia obtained according to the rotation angle of the base unit, and the reference inertia, the reference unbalanced load, and the reference time constant from the feedback information regarding the base unit. and a controller for calculating the time constant of the part. 2. The control device according to claim 1, wherein the speed control unit has a moving average filter that limits maximum acceleration during speed control of the base unit using the time constant calculated by the calculation unit. 3. The control device according to claim 2, wherein said speed adjuster has a plurality of moving average filters including said moving average filter. The base unit includes another part, the holding base being arranged at one end and being heavier than the holding base,
2. The control device according to claim 1, wherein said rotating shaft is unevenly distributed near said one end of said base unit. 2. The control device according to claim 1, wherein the reference inertia and the reference unbalanced load are inertia and unbalanced load when the unbalanced load of the platform unit is maximum. 6. The control device according to any one of claims 1 to 5, wherein the calculation element includes a rotation range of the base unit. In a speed control method for controlling the speed at which a table unit having a plurality of parts arranged side by side in one direction, including a work holding table, rotates around a rotation axis intersecting the one direction,
Memorize the standard inertia, standard unbalanced load, and standard time constant,
obtaining an unbalanced load and inertia according to the rotation angle of the base unit from feedback information about the base unit;
A speed control method of calculating a time constant used for controlling the speed based on the obtained unbalanced load and inertia and calculation elements including the contents of the memory.

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