JP4437801B2 - Numerical control method and speed control device - Google Patents

Description

  The present invention relates to a numerical control method and a speed control apparatus for determining an allowable speed of a movable part, and in particular, a control apparatus for controlling the speed of a movable part so as not to exceed the determined allowable speed, for example, a numerical value The present invention relates to a numerical control method suitable for a control device such as a control device, a robot control device, a sequencer, a moving body such as an elevator, a sewing machine, a coordinate measuring device, a plotter, a belt conveyor, an automobile or a train, or an aircraft.

  Hereinafter, a conventional numerical control method will be described. Generally, when controlling the operation of the movable part, the mechanical vibration becomes larger as the operation is faster. Therefore, the maximum speed (allowable speed) allowable for mechanical vibration is obtained, and control is performed so that the speed of the movable part does not exceed the allowable speed.

  As an allowable speed determination method in the conventional numerical control method, for example, there is a method described in Patent Document 1 below. In this patent document, for example, a movement trajectory is a path that sequentially passes through a plurality of target points P1, P2,..., Pn, and line segment data Xk and a maximum speed command for a section k connecting arbitrary points Pk and Pk + 1 on this path. When the value F0 is input, an allowable speed equal to or lower than the allowable normal acceleration determined according to the curvature of the section k is obtained based on the line segment data of the section k and its vicinity and the maximum speed command value F0.

  In addition, as an allowable speed determination method in another conventional numerical control method, for example, there is a method described in Patent Document 2 below. In this patent document, the allowable speed is determined based on the speed difference between two adjacent blocks. That is, when the maximum speed change determined from the maximum torque of the motor or shock to the machine is obtained in advance and machining is performed at the maximum cutting speed set separately, and the speed change for each axis in the corner exceeds the maximum speed change In addition, the feed speed that is the maximum within the range not exceeding is obtained.

JP-A-2-219107 Japanese Patent Laid-Open No. 2-72414

  However, the above-described allowable speed determination method in the conventional numerical control method has the following problems.

  For example, there is a case where mechanical vibration is indirectly reduced by suppressing the acceleration or speed difference below the allowable value as described above. However, when the movement time is further shortened and the operation speed is increased as in recent years. In addition, it has been found that the above-described conventional technique is insufficient in suppressing mechanical vibration.

  Here, the method described in Patent Document 1 will be described as an example. For example, in order to prevent mechanical vibrations from occurring, there is a method of sufficiently reducing the allowable acceleration value. However, in such a method, for example, when the mechanical vibration does not occur even though the acceleration is larger than the allowable value, there is a problem in that the speed is unnecessarily lowered and the machining efficiency is lowered. there were.

  Current problems will be specifically described with reference to the drawings. 15, FIG. 16, FIG. 17, FIG. 18, and FIG. 19 are diagrams for explaining conventional problems. First, a description will be given of a case of operating according to a command path and a command speed as shown in FIG. In the figure, P0 to P2 are the start and end points of each line segment constituting the command path, and move in the order of P0, P1, and P2. Further, F shown in each line segment represents a command speed (mm / min).

For example, when passing at the command speed, the speed difference generated at the point P1 is
X axis: 1000 × (COS (π / 2) −COS (−π / 2)) = 0
Y axis: 1000 × (SIN (π / 2) −SIN (−π / 2)) = 1000√2. Here, for example, if the allowable speed difference between the X axis and the Y axis is 300√2, the allowable speed at the point P1 is
1000 × 300√2 / 1000√2 = 300
It becomes.

FIG. 16 shows the vibration generated in the machine when passing in the vicinity of the point P1 at this speed 300, and more specifically, shows the acceleration waveform of the Y axis. Note that the X-axis acceleration is 0, and is omitted. The resonance frequency of the machine is 20 Hz, and the attenuation ratio is 0.1. In this case, the generated mechanical vibration is 0.78 m / s ^{2 at the} maximum.

  Next, a description will be given of a case of operating according to a command path and a command speed as shown in FIG. In the figure, P0 to P3 are the start and end points of each line segment constituting the command path, and move in the order of P0, P1, P2, and P3. In FIG. 17, the points P1 and P2 appear to overlap, but are actually separated by 10 μm (see FIG. 18).

For example, the speed difference that occurs at point P1 when passing at the command speed is
X axis: 1000 × (COS (π / 2) −COS (0))
= 1000 × (√2 / 2-1)
Y axis: 1000 × (SIN (π / 2) −SIN (0))
= 1000 × (√2 / 2)
It becomes. Here, if the allowable speed difference between the X axis and the Y axis is 300√2, the allowable speed at the point P1 is
1000 × min (300√2 / (1000 (√2 / 2-1)),
300√2 / (1000 (√2 / 2))) = 600
It becomes.

FIG. 19 shows the vibration generated in the machine when passing in the vicinity of the point P1 at the speed 600, and more specifically, shows the acceleration waveform of the Y axis. Note that the X-axis acceleration is smaller than the Y-axis acceleration, and is therefore omitted. In this case, the generated mechanical vibration is 1.26 m / s ^{2 at the} maximum.

Thus, according to the prior art, as shown in FIG. 15 and FIG. 17, the magnitude of the generated mechanical vibration is greatly different even if the shape is slightly different, and the mechanical vibration cannot be managed correctly. I understand. Specifically, for example, when the mechanical vibration is limited to 0.78 m / s ² or less, the allowable speed difference needs to be about half of the current state, that is, 150√2. However, with this setting, the permissible speed is 150 (the vibration at this time is 0.39 m / s ² ) with respect to the command path of FIG. That is, the processing efficiency decreases.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a numerical control method and a speed control device that can realize accurate management of mechanical vibration (allowable speed) and improvement of processing efficiency.

In order to solve the above-described problems and achieve the object, a numerical control method according to the present invention is a numerical control method for controlling movement of two or more movable parts according to a command speed along a command path. Based on the command speed along the command path and the command speed along the command path, the command speed of the movable unit is determined based on the command speed along the command path and the command speed along the command path. A speed control unit that controls the speed along the command path so as not to exceed the command speed along the command path and the permissible speed along the command path, and the permissible speed determination unit from the specific point or the specific region A command reading path that reads a command path along a predetermined movement time range or a predetermined movement distance range from the specific point or specific region and a command speed along the command path. And a speed command generation step for temporarily generating a temporary speed command for each axis at each time based on the command path and a command speed along the command path, and a temporary speed command for each axis at each time A frequency component calculating step for calculating a frequency band component of each axis corresponding to mechanical vibration, and a minimum value of a ratio of the frequency band component of each axis to a preset reference value of the frequency band component Or an allowable speed determination step for calculating an allowable speed along the command path of the specific region from a ratio of a square root sum of squares of the frequency band components of each axis to a reference value of a preset frequency band component; It is characterized by including.

  According to the numerical control method of the present invention, the allowable speed is obtained based on the frequency component corresponding to the mechanical vibration, so that accurate management of the mechanical vibration (allowable speed) and improvement of the processing efficiency are realized. There is an effect that can be.

  Embodiments of a numerical control method and a speed control device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a speed control device according to the present invention. In FIG. 1, 1 is an allowable speed determination unit, 2 is a speed control unit, 3 is a movable unit (control target), and the speed control device includes an allowable speed determination unit 1 and a speed control unit 2. The The allowable speed determination unit 1 determines the allowable speed according to a numerical control method described later. Here, the allowable speed is determined based on the command path and the command speed. The speed control unit 2 controls the speed of the movable unit (control target) 3 along the command path. At this time, control is performed so that the speed to be controlled does not exceed the command speed and the allowable speed.

  Hereinafter, the numerical control method according to the first embodiment will be described. FIG. 2 is a flowchart showing the numerical control method of the first embodiment realized by the allowable speed determining unit 1 of the speed control device according to the present invention. Here, the numerical control method according to the first embodiment will be specifically described using the examples of FIGS. 15 and 17 again.

  First, a description will be given of a case of operating according to a command path and a command speed as shown in FIG. Here, for example, the allowable speed of the point P1 is determined. The allowable speed determination unit 1 of the speed control device reads the command path and the command speed (step S1). Note that the command route and command speed within a predetermined time or distance range including the point P1 are read.

  FIG. 3 is a diagram illustrating an example of reading a command route and a command speed within the range of the distance L, for example. In this case, along the command path for the point P1, the command path is in the range of distance L in the direction opposite to the traveling direction (the range of A to P1 and the range of P1 to B along the command path in the figure). Read the command speed.

  However, the range for reading the command path and the command speed may be determined within a predetermined time range, or may be determined using both time and distance. For example, the time from the point P1 (required time) can be obtained by “time = d / command speed” where d is the distance along the command path from the point P1. In general, the command path and the command speed are often defined in the operation program. In this case, the command path and the command speed before (past) the point P1 are stored, and after the point P1 ( The future command path and command speed are prefetched. The predetermined time is preferably at least ¼ of the period in order to accurately extract the mechanical vibration frequency component. Further, for the same reason, the predetermined distance is preferably not less than 1/4 of the product of the mechanical vibration frequency and the command feed speed.

After reading the command path and the command speed, the permissible speed determination unit 1 generates a speed command (speed command waveform) at each time from the permissible speed calculated based on each command (step S2). FIG. 4 is a diagram showing a speed command waveform for each axis in the case of FIG. 3 described above, for example. In the figure, Vx represents an X-axis speed command waveform, and Vy represents a Y-axis speed command waveform. The value of the speed of each axis in each block can be expressed by the following equations (1) and (2), where θ is the angle formed with respect to the X axis of the line segment and F is the command speed. This calculation process is performed for the entire range determined in step S1.
Vx = F × cos θ (1)
Vy = F × sin θ (2)

  After generating the speed command waveform for each axis, the allowable speed determining unit 1 obtains a frequency component corresponding to the mechanical vibration (step S3). For example, here, FFT calculation (discrete Fourier calculation) is performed on the velocity command waveform Vy obtained in step S2, and the spectrum is obtained. FIG. 5 is a diagram showing a spectrum corresponding to the speed command waveform Vy. In this case, the magnitude G of the frequency component (circle mark in the figure) corresponding to the mechanical vibration was 6.93.

After obtaining the frequency component corresponding to the mechanical vibration, the permissible speed determining unit 1 uses the magnitude G of the frequency component and its reference value Vmax (here, 2.079), and the following (3) An allowable speed is obtained by an equation (step S4).
Allowable speed = Command speed x Vmax / G
= 1000 × 2.079 / 6.93 = 300 (3)

FIG. 6 is a diagram showing the vibration generated in the machine when passing near the point P1 at the speed 300. As shown in FIG. Here, in particular, the acceleration waveform of the Y axis is shown. As shown in the figure, the generated mechanical vibration is 0.78 m / s ^{2 at the} maximum.

  Next, a description will be given of a case of operating according to a command path and a command speed as shown in FIG. Also in this case, as described above, the speed control device reads the command path and the command speed (step S1). FIG. 7 is a diagram illustrating an example of reading a command route and a command speed within the range of the distance L, for example. In this case, along the command path for the point P1, the command path is in the range of distance L in the direction opposite to the traveling direction (the range of A to P1 and the range of P1 to B along the command path in the figure). Read the command speed. Then, a speed command waveform is generated based on each command (step S2). FIG. 8 is a diagram showing the speed command waveform of each axis obtained in step S2.

  After generating the speed command waveform for each axis, the speed control device obtains a frequency component corresponding to the mechanical vibration (step S3). Similar to the above, FFT calculation (discrete Fourier calculation) is performed on the speed command waveform Vy to obtain its spectrum. FIG. 9 is a diagram showing a spectrum corresponding to the speed command waveform Vy. In this case, the magnitude G of the frequency component (circle mark in the figure) corresponding to the mechanical vibration was 6.88.

After obtaining the frequency component corresponding to the mechanical vibration, the speed control apparatus uses the magnitude G of the frequency component and its reference value Vmax (here, 2.079) to obtain the following equation (4). An allowable speed is obtained (step S4).
Allowable speed = command speed x Vmax / G
= 1000 × 2.079 / 6.88 = 302 (4)

FIG. 10 is a diagram showing the vibration generated in the machine when passing near the point P1 at the speed 302. As shown in FIG. Here, in particular, the acceleration waveform of the Y axis is shown. As shown in the figure, the generated mechanical vibration is 0.69 m / s ^{2 at the} maximum.

  As described above, in this embodiment, since the allowable speed is obtained based on the frequency component corresponding to the mechanical vibration, the mechanical vibration can be managed with high accuracy, thereby realizing a smooth operation without a shock. it can. Further, the operation time can be shortened without decelerating more than necessary as compared with the prior art.

  In step S2, the speed command waveform for each axis is generated with the command speed in the vicinity of the point for obtaining the permissible speed as a constant command speed F. In addition, when acceleration / deceleration occurs in the middle of the block, The speed command waveform of each axis may be generated in consideration of the acceleration / deceleration. Thereby, the subsequent calculation accuracy is improved. Moreover, it is good also as estimating the speed waveform of each axis | shaft of a machine from the speed command waveform of each axis | shaft using the response characteristic of a servo system. Thereby, the subsequent calculation accuracy is further improved.

  In step S2, a command speed waveform is generated, but instead of the speed command, position, acceleration, jerk may be calculated, and the frequency component may be obtained. The position can be easily obtained by integrating the speed command, and the acceleration and jerk can be easily obtained by differentiating the speed once or twice.

  In step S3, FFT calculation is used. However, wavelet transform, Laplace transform, calculation using a high pass / low pass / band pass filter, and correlation coefficient calculation with a predetermined time waveform may be used. A continuous time domain calculation method or a discrete time domain calculation method may be applied to the result.

  In step S3, attention is focused on one frequency component. For example, when there are a plurality of mechanical vibration modes, when the mechanical frequency changes, or when the mechanical frequency is unknown, attention is paid to the plurality of frequency components. The allowable speed may be obtained using the maximum value, average value, weighted average value, or the like.

In step S4, the reference value Vmax may be provided for each axis or may be provided for all axes. When each axis is provided, the frequency component of each axis is Gj, the reference value is Vmaxj (j = 1, 2,..., N (n is the number of axes)), and the following equation (5) is used. Calculate the allowable speed.
Allowable speed = min (Vmax1 / G1, Vmax2 / G2,..., Vmaxn / Gn)
... (5)
When the vibration characteristics of the machine are different for each axis, more precise vibration control can be performed by providing a reference value for each axis. On the other hand, when providing for all axes in common, the reference speed is set to Vmax, and the allowable speed is calculated using the following formula (6) or (7).
Allowable speed = min (Vmax / G1, Vmax / G2,..., Vmax / Gn)
... (6)
Allowable speed = Vmax / √ (G1 ² + G2 ² +... + Gn ² ) (7)
When the difference in the vibration characteristics of the machine for each axis is small, the labor for parameter setting and adjustment can be reduced by using a common reference value.

  In the present embodiment, the command speed information is used in step S1, step S2, and step S4. However, the calculation can be performed without using the command speed. For example, instead of the command speed, the maximum driveable speed or unit speed of each axis may be used.

  In this embodiment, the allowable speed at the end point of a certain block is obtained. For example, as shown in FIG. 11, all the small regions (Z0, Z1,..., Zk,. It is also possible to determine the allowable speed of the points. Accordingly, even when the curvature changes in the middle of a block such as a spline curve or a NURBS curve, more accurate mechanical vibration control can be performed.

  In this embodiment, the permissible speed of the point is obtained, but it is also possible to obtain the permissible speed of the entire block or the entire small area. In this case, in step S1, command paths and command speeds within a predetermined distance or time range are read before and after the entire block or the entire small area.

  In the present embodiment, since the allowable speed is obtained based on the frequency component corresponding to the mechanical vibration, it is possible to manage the mechanical vibration with high accuracy, thereby realizing a smooth operation without a shock. There is an effect that it is possible. In addition, since the operation time can be shortened without decelerating more than necessary, it is possible to improve the processing efficiency as compared with the prior art.

  In this embodiment, since a specific frequency component can be extracted by various methods, it is possible to adaptively manage mechanical vibration.

  Furthermore, in the present embodiment, for example, when the vibration characteristics of the machine are different for each axis, the reference value is provided for each axis, so that the vibration can be controlled more precisely. Further, when the difference between the axes of the vibration characteristics of the machine is small, since the reference value is made common, it is possible to reduce the labor of parameter setting and adjustment.

Embodiment 2. FIG.
In the first embodiment, the allowable speed is obtained in step S4 so as to be proportional to the reciprocal of the frequency component G. However, since the allowable speed and the frequency component depend on the surrounding shape, they may not necessarily have an inversely proportional relationship. is there. Therefore, in the second embodiment, repeated calculation is performed in order to obtain the allowable speed with higher accuracy. The speed control device of the present embodiment is the same as that of the first embodiment described above with reference to FIG.

  Hereinafter, the numerical control method according to the second embodiment will be described. FIG. 12 is a flowchart showing the numerical control method of the second embodiment realized by the allowable speed determining unit 1 of the speed control device according to the present invention. In addition, about the process of step S1-S3 in a figure, it is the same as FIG.

  After obtaining the frequency component corresponding to the mechanical vibration in step S3, the allowable speed determination unit 1 determines whether or not the iterative calculation may be terminated (step S5). For example, if the frequency component matches the reference value (step S5, Yes), the allowable speed determination unit 1 ends the process. On the other hand, when the termination is impossible (step S5, No), the allowable speed is calculated by the same procedure as step S4 of the first embodiment (step S4).

  Next, as the second process, the processes of steps S1 to S3 are performed again. Here, since the processing of steps S1 to S3 is performed in consideration of the allowable speed obtained in step S4, a calculation result different from the first processing is obtained.

  The allowable speed determination unit 1 calculates the time from the point where the allowable speed is calculated as “time = distance / min (command speed, allowable speed)”, and reads the command path, the command speed, and the allowable speed within this time range. (Step S1).

  After reading the command path, the command speed, and the permissible speed, the permissible speed determination unit 1 generates a speed command at each time as in the first embodiment (step S2), and further, frequency components corresponding to mechanical vibrations. G is obtained (step S3). In step S2, a temporary speed command waveform is generated using the smaller one of the command speed and the allowable speed.

Thereafter, the allowable speed determination unit 1 ends the process when the frequency component is sufficiently close to the allowable value, when the change in the calculated value of the allowable speed is sufficiently small, or when the number of repetitions k is sufficiently large (step S5). Specifically, the following conditional expressions (8) to (12) are used.
| G−Vmax | <ε1 (8)
| G / Vmax-1 | <ε2 (9)
| Fa (k) −Fa (k−1) | <ε3 (10)
| Fa (k) / Fa (k-1) -1 | <ε4 (11)
Number of repetitions> Maximum number of repetitions (12)
Ε1 represents the maximum frequency component error amount, ε2 represents the maximum frequency component change ratio, ε3 represents the maximum permissible speed error amount, ε4 represents the maximum permissible speed change ratio, and Fa (k) is the kth time. Indicates the obtained allowable speed.

  As described above, in the present embodiment, the allowable speed can be obtained with higher accuracy by repetitive processing, so that more accurate mechanical vibration control and a shorter processing time can be achieved.

Embodiment 3 FIG.
In the first and second embodiments, the mechanical vibration is accurately managed by using the allowable speed calculation method (step S4) focusing on the mechanical vibration. However, in the third embodiment, the trajectory error, speed, acceleration, and acceleration are further increased. Different feature quantities such as speed and speed difference should not exceed their permissible values. The speed control device of the present embodiment is the same as that of the first embodiment described above with reference to FIG. Further, processes other than step S4 in the numerical control method described above are the same as those in the first and second embodiments.

  Hereinafter, the numerical control method according to the third embodiment will be described. FIG. 13 is a flowchart showing the numerical control method of the third embodiment realized by the allowable speed determining unit 1 of the speed control device according to the present invention.

  Here, in step S4 described above, the allowable speed calculation method focusing on the mechanical vibration (step S100) and the allowable speed calculation method based on a feature quantity different from the mechanical vibration (step S101) are used in combination. In step S101, for example, a known method described in the prior art is used. When the allowable speeds obtained in step S100 and step S101 are Fa1 and Fa2, respectively, the allowable speed determination unit 1 finally adopts the smaller of both as the allowable speed (step S200). Note that the order of step S100 and step S101 may be interchanged. Further, as shown in FIG. 14, n allowable speed calculation methods may be used together (steps S100, S101,..., S109, S201). In this case, the order of the first to nth allowable speed calculation methods may be changed.

  As described above, according to the present embodiment, not only mechanical vibration but also feature quantities such as trajectory error, speed, acceleration, jerk, and speed difference can be managed.

  In the present embodiment, it is also possible to accurately extract a mechanical vibration frequency component.

  As described above, the numerical control method and the speed control device according to the present invention provide a control device that controls the speed of the movable part so as not to exceed the determined allowable speed, for example, a numerical control device, a robot control device, a sequencer, It is useful for mobile devices such as elevators, sewing machines, coordinate measuring instruments, plotters, belt conveyors, automobiles, trains, etc., and control devices such as aircraft.

It is a figure which shows the structure of the speed control apparatus concerning this invention. 3 is a flowchart illustrating a numerical control method according to the first embodiment. It is a figure which shows an example in the case of reading a command path | route and command speed. It is a figure which shows an example of the speed command waveform of each axis. It is a figure which shows an example of the spectrum corresponding to a speed command waveform. It is a figure which shows an example of the vibration which generate | occur | produces in a machine. It is a figure which shows an example in the case of reading a command path | route and command speed. It is a figure which shows an example of the speed command waveform of each axis. It is a figure which shows an example of the spectrum corresponding to a speed command waveform. It is a figure which shows an example of the vibration which generate | occur | produces in a machine. It is a figure which shows the case where the permissible speed of the start / end point of the small area which subdivided the block further is calculated | required. 6 is a flowchart illustrating a numerical control method according to the second embodiment. 10 is a flowchart illustrating an example of a numerical control method according to the third embodiment. 10 is a flowchart illustrating an example of a numerical control method according to the third embodiment. It is a figure for demonstrating the conventional problem. It is a figure for demonstrating the conventional problem. It is a figure for demonstrating the conventional problem. It is a figure for demonstrating the conventional problem. It is a figure for demonstrating the conventional problem.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Allowable speed determination part 2 Speed control part 3 Movable part (control object)

Claims (8)

In a numerical control method for controlling movement of two or more axes along a command path according to a command speed,
An allowable speed determining unit for determining an allowable speed along the command path at a specific point or a specific area on the command path;
Based on the command speed along the command path and the permissible speed along the command path, the speed along the command path of the movable part is set to the command speed along the command path and the permissible speed along the command path. A speed control unit for controlling so as not to exceed,
With
The allowable speed determining unit
A command reading step of reading a command path along a command path and a command path of a range of a predetermined movement time from the specific point or the specific region, or a range of a predetermined movement distance from the specific point or the specific region;
Based on the command path and the command speed along the command path, a speed command generation step for temporarily generating a temporary speed command for each axis at each time;
A frequency component calculating step for calculating a frequency band component of each axis corresponding to mechanical vibration included in the temporary speed command of each axis at each time;
The minimum value of the ratio of the frequency band components of each axis to the preset frequency band component reference value, or the sum of squares of the frequency band components of each axis to the preset frequency band component reference value A permissible speed determining step of calculating a permissible speed along the command path of the specific region from a ratio of square roots ;
The numerical control method characterized by including.   The numerical control method according to claim 1, wherein the specific region is a region between the specific points or a small region obtained by further subdividing the region between the specific points.   The numerical control method according to claim 1, wherein the reference value is provided for each axis or is provided for all axes.   The change in the calculated value of the velocity along the command path is designated in advance until the frequency band component of each axis corresponding to the mechanical vibration falls within the range of the first tolerance specified in advance for the tolerance. The command reading step, the speed command generating step, the frequency component calculating step, and the allowable speed determining step until the second allowable error is reached or until the number of repeated calculations exceeds a predetermined number of times. The numerical control method according to claim 1, wherein the steps are repeatedly executed. In a speed control device that controls movement of a movable part of two or more axes along a command path according to a command speed,
An allowable speed determining unit for determining an allowable speed along the command path at a specific point or a specific area on the command path;
Based on the command speed along the command path and the permissible speed along the command path, the speed along the command path of the movable part is set to the command speed along the command path and the permissible speed along the command path. A speed control unit for controlling so as not to exceed,
With
The allowable speed determining unit
A command reading means for reading a command speed along a command path and a command path of a range of a predetermined movement time from the specific point or the specific region, or a range of a predetermined movement distance from the specific point or the specific region;
Based on the command path and the command speed along the command path, speed command generation means for temporarily generating a temporary speed command for each axis at each time;
A frequency component calculating means for calculating a frequency band component of each axis corresponding to mechanical vibration included in the provisional speed command of each axis at each time;
The minimum value of the ratio of the frequency band components of each axis to the preset frequency band component reference value, or the sum of squares of the frequency band components of each axis to the preset frequency band component reference value An allowable speed determining means for calculating an allowable speed along the command path of the specific area from a ratio of square roots ;
A speed control device comprising:   The speed control apparatus according to claim 5, wherein the specific area is an area between the specific points or a small area obtained by further subdividing the area between the specific points.   The speed control apparatus according to claim 5 or 6, wherein the reference value is provided for each axis, or is provided for all axes in common.   The change in the calculated value of the velocity along the command path is designated in advance until the frequency band component of each axis corresponding to the mechanical vibration falls within the range of the first tolerance specified in advance for the tolerance. The command reading means, the speed command generating means, the frequency component calculating means, and the allowable speed determining means until the second allowable error is reached or until the number of repeated calculations exceeds a predetermined number of times. The speed control apparatus according to any one of claims 5 to 7, wherein the processing of each means is repeatedly executed.

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