JP2008046899A - Numerical controller - Google Patents

Abstract

A numerical control device that shortens a movement time while maintaining a trajectory error due to a change to a speed pattern with a short movement time.
A speed pattern determination unit 2 that determines a control speed pattern variable 10, a position error calculation unit 3 that calculates a reference position error 11, and a movement start that controls a next block movement command start point 13 of a moving object. A point control unit 4 and an acceleration / deceleration control unit 5 that outputs a position command 14 for the moving body are provided. The position error calculation unit 3 calculates a reference position error 11 when the reference speed pattern is used, and the movement start point control unit 4 determines the next block movement command start point 13 of the moving body based on the reference position error 11. By adjusting, the time is shortened while maintaining the reference position error 11 even if the speed pattern is changed.
[Selection] Figure 1

Description

  The present invention relates to a numerical control device for controlling a numerically controlled machine tool or a robot having a moving body driven by a driving device (servo motor or the like), and more particularly to a novel improvement of a moving body acceleration / deceleration system.

In general, in acceleration / deceleration processing of a moving body using a servo motor or the like as a driving device, a speed command for driving the moving body is limited so as not to exceed the maximum torque (allowable torque) of the servo motor.
The main acceleration / deceleration methods include, for example, linear acceleration / deceleration in which the velocity command has a linear waveform (acceleration is constant), and S-curve acceleration / deceleration in which the velocity command has an S-shaped waveform (acceleration is trapezoidal). Is known.

  Also, industrial machines such as machine tools and robots are required to improve their productivity by shortening their operating time as much as possible, especially movement (processing) that is not directly related to processing work or assembly work. In an approach such as fast-forwarding to the start position), it is required to reduce the time as much as possible.

  Therefore, when the moving distance of the moving body is short and the servo motor speed cannot be increased to the command speed, the servo motor is increased by increasing the command acceleration from the normal acceleration in order to shorten the moving time of the moving body. A technique for increasing the speed has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 2722286

  In the conventional numerical control apparatus, when the moving time or moving distance of the moving body is short as in Patent Document 1, in order to shorten the moving time, the command speed gradient (command acceleration However, if the speed pattern is changed so that it is larger than usual, there is a problem that the position error increases.

Such an increase in position error becomes more noticeable as the command acceleration is set larger. In particular, the speed pattern is changed to a rectangular wave command (speed command on the step, equivalent to infinite acceleration) that minimizes the movement time. It becomes noticeable when changing.
If the position error increases in this way, work to be performed at the target position (for example, machining operation such as drilling) cannot be performed with high accuracy, and collision (interference) with other members or movable parts may occur. There was a problem.

  Therefore, when actually using the technique of the above-mentioned Patent Document 1, necessary accuracy can be realized in each block (movement command) to which the changed speed pattern is applied, and interference does not occur. However, there is a problem that it is necessary to perform manual rechecks one by one while actually testing the machining program, which requires a lot of labor and time.

  The present invention has been made to solve the above problems, and by selecting a speed pattern with a short movement time according to a movement command, it is possible to calculate a reference position error in the reference speed pattern, and It is an object of the present invention to obtain a numerical control device that can shorten the movement time while maintaining the reference position error in the reference speed pattern even if the change is made.

  In the numerical control device according to the present invention, a reference speed pattern, which is a reference speed pattern in which a moving body can move by giving a moving command with acceleration / deceleration to a moving body having a driving device, In a numerical control apparatus that performs control according to a second speed pattern that is a different speed pattern, each moving time of the moving body is compared with the reference speed pattern and the second speed pattern, and the shorter moving time is compared. Corresponds to the speed pattern determination unit that determines the speed pattern variable of the speed pattern as the control speed pattern variable, the position error calculation unit that calculates the reference position error based on the movement command and the reference speed pattern, and the control speed pattern variable So that the position error when the moving body moves according to the velocity pattern matches the reference position error. A movement start point control unit that controls the command start point; and an acceleration / deceleration control unit that outputs a position command to the moving body using the movement command, the control speed pattern variable, and the next block movement command start point as input information. The position error calculation unit calculates the reference position error when using the reference speed pattern, and the movement start point control unit adjusts the next block movement command start point of the moving body based on the reference position error. is there.

  According to the present invention, a speed pattern with a short movement time can be selected according to the movement command, and a reference position error can be calculated with the reference speed pattern. By keeping the trajectory error (reference position error), it is possible to shorten the movement time while keeping the accuracy at the command end point within the range of the desired accuracy.

Embodiment 1 FIG.
As described above, in general, in a machine tool, there are a cutting feed command used when cutting a workpiece and a fast feed command used for moving a tool without cutting.
In the case of a fast-forward command, the trajectory accuracy from the start point to the end point of movement is not emphasized, and the accuracy at the command end point position (target position) of the movement command and the reduction of the movement time until reaching the target position are In particular, it is required to reduce the movement time while keeping the accuracy at the command end point within the range of desired accuracy.

  Therefore, in-position control is generally performed and the movement is completed when the servo motor position reaches within the in-position width (allowable position error) from the command end point position without waiting for the servo motor position to reach the command end point position. And the next block movement command is started.

  Also, at locations where high position accuracy is not required, in order to further reduce the movement time compared to in-position control, it is determined that the movement has been completed when the command position after acceleration / deceleration falls within the allowable position error range. In many cases, control for starting the block movement command is performed.

In the first embodiment of the present invention, the same accuracy as that in the case where the normal speed pattern control is executed and the case where the start timing control of the next block movement command described above is executed is maintained. By operating with a speed pattern different from the speed pattern, a numerical control device capable of shortening the movement time is realized.
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a numerical control apparatus 100 according to Embodiment 1 of the present invention, and shows a case where it is applied to NC processing of a machine tool or the like.

In FIG. 1, a numerical control device 100 includes a speed pattern determination unit 2, a position error calculation unit, and a movement command 9 from the machining program 1, and a speed pattern parameter 7 and a start point parameter 8 that are manually input. 3, a movement start point control unit 4, and an acceleration / deceleration control unit 5.
Further, the numerical control device 100 includes a servo control unit 6 for driving a servo motor 50 that is a driving device for a moving body (not shown).

The speed pattern determination unit 2 outputs a control speed pattern variable 10 using the movement command 9 and the speed pattern parameter 7 as input information.
The position error calculation unit 3 outputs a reference position error 11 using the movement command 9, the speed pattern parameter 7 and the start point parameter 8 as input information.

The movement start point control unit 4 outputs the next block movement command start point 13 using the start point parameter 8, the control speed pattern variable 10, the reference position error 11, the current position 12 and the position command 14 as input information.
The acceleration / deceleration control unit 5 outputs a position command 14 using the movement command 9, the control speed pattern variable 10 and the next block movement command start point 13 as input information.
The servo control unit 6 outputs the current position 12 of the servo motor 50 using the position command 14 as input information.

  In the numerical controller 100, the speed pattern determination unit 2 determines a control speed pattern variable 10 that defines a speed pattern based on the movement command 9 commanded by the machining program 1 and a plurality of speed pattern parameters 7. Then, the control speed pattern variable 10 is input to the movement start point control unit 4 and the acceleration / deceleration control unit 5.

  The position error calculation unit 3 is based on the movement command 9 commanded by the machining program 1, the reference speed pattern parameter included in the speed pattern parameter 7, and the start point parameter 8. The reference position error 11 is calculated, and the reference position error 11 is input to the movement start point control unit 4.

The movement start point control unit 4 calculates the next block movement command start point 13 based on the start point parameter 8 and inputs the next block movement command start point 13 to the acceleration / deceleration control unit 5, thereby Control the starting point of
Specifically, the movement start point control unit 4 includes a start point parameter 8, a reference position error 11 that is an index value for determining the next block movement command start point 13, a control speed pattern variable 10, Based on the position command 14 (or the current position 12 calculated by the position command 14 and the servo model or the current position 12 detected by the servo control unit 6), the next block movement command start point 13 is obtained. To control.

The acceleration / deceleration control unit 5 creates a position command 14 using the movement command 9 commanded by the machining program 1, the next block movement command start point 13, and the control speed pattern variable 10 as input information, and performs servo control. Output to unit 6.
The servo control unit 6 drives and controls the servo motor 50 based on the position command 14 and drives a moving body (not shown) such as a machine tool to realize a desired operation.

  The start point parameter 8 is a parameter for defining the next block movement command start point 13 in the speed pattern, and includes an index for determining the next block movement command start point 13 and a value of the index. Yes.

  Examples of the index include an in-position width, a command in-position width (deviation between the movement amount of the movement command 9 and the position command 14), and a trajectory error (path error, inner amount E at a corner portion, etc.). Here, when the index is “command in-position width” and the index value Dsi is “0”, the command payout time Tsi (the time when the command in-position width becomes “0” or the command end time) is Since the block movement command start point 13 is set, the next block command is executed simultaneously with the completion of the command payout.

The reference position error 11 calculated by the position error calculation unit 3 is the droop amount Dr (the difference between the position command 14 and the current position 12) at the next block movement command start point 13 when the reference speed pattern P1 is used. ).
Here, as a specific example of the position error calculation unit 3, a case where the reference speed pattern P1 is a triangle command and the reference position error 11 is a droop amount Dr at the command payout time Tsi as described later is shown.

Next, the operation according to the first embodiment of the present invention shown in FIG. 1 will be described.
First, as described above, the speed pattern determination unit 2 determines the control speed pattern variable 10 that defines the speed pattern from the movement command 9 commanded by the machining program 1 and the plurality of speed pattern parameters 7. At this time, the movement command 9 is a command relating to the moving path and moving speed of the moving body. Specifically, the movement amount (or start point, end point) of each axis, the type of moving path (straight line, arc, etc.), cutting The feed / fast-forward distinction and the moving speed are shown.

  The speed pattern parameter 7 is a parameter that defines a speed pattern (speed waveform), and defines a reference speed pattern parameter that defines the reference speed pattern P1 and a second speed pattern P2 that is different from the reference speed pattern P1. And a second speed pattern parameter.

  The reference speed pattern P1 is moved even at the maximum speed of the axis, especially in the case of all movement commands that can be commanded by the machine tool (for example, the length of the movement amount, the movement speed is high or low). Even in this case, the velocity pattern using the velocity pattern parameter adjusted in advance is shown so that the velocity V and the acceleration α of the moving body do not exceed the allowable values and the vibration accompanying the movement is sufficiently small.

  On the other hand, the second speed pattern P2 is a speed pattern using speed pattern parameters servo-adjusted in advance, like the reference speed pattern P1, but is a different speed pattern from the reference speed pattern P1.

Each speed pattern of the reference speed pattern P1 and the second speed pattern P2 includes an S-curve acceleration / deceleration command, a linear acceleration / deceleration command (triangle command or trapezoid command (acceleration / deceleration command whose command speed is a trapezoid)), rectangular It is selected from wave commands.
Therefore, the speed pattern parameter 7 corresponds to the first and second time constants and the command speed in the case of the S-curve acceleration / deceleration command, and in the case of linear acceleration / deceleration, the time constant (acceleration time or deceleration time) or It corresponds to the command acceleration α * and the command speed V *, and in the case of a rectangular wave command, it corresponds to the command speed V *.
The selected speed pattern may be a pattern other than the above speed pattern.

Next, a specific determination process of the control speed pattern variable 10 by the speed pattern determination unit 2 will be described with reference to the flowchart shown in FIG.
In FIG. 2, first, the speed pattern parameter 7 and the movement command 9 commanded by the machining program 1 are read (step 200), the movement command 9, the reference speed pattern parameter included in the speed pattern parameter 7, and the servo motor 50. The reference movement time t1 is calculated based on the servo model corresponding to (step 201).

  Subsequently, a second movement time t2 is calculated based on the movement command 9, the second speed pattern parameter included in the speed pattern parameter 7, and the servo model (step 202), and the reference movement time t1 and the first movement time t1 are calculated. 2 is compared with the moving time t2 to determine whether or not the relationship of t1 <t2 is satisfied (step 203).

If it is determined in step 203 that t1 <t2 (that is, YES), the movement speed t1 in the reference speed pattern P1 is shorter than the movement time t2 in the second speed pattern P2. The parameter is selected as the control speed pattern variable 10 (step 204).
On the other hand, if it is determined in step 203 that t1 ≧ t2 (that is, NO), the movement time t2 in the second speed pattern P2 is shorter than the movement time t1 in the reference speed pattern P1, so that the first The second speed pattern parameter is selected as the control speed pattern variable 10 (step 205).

Finally, the control speed pattern variable 10 selected in steps 204 and 205 is determined (step 206), and the processing routine of FIG. 2 is terminated.
Through the above steps 200 to 206, the control speed pattern variable 10 determined by the speed pattern determination unit 2 is output.

The reference movement time t1 and the second movement time t2 calculated in the above steps 201 and 202 indicate the movement times when the moving body moves in the reference speed pattern P1 and the second speed pattern P2, respectively. ing.
Further, each movement time (reference movement time t1, second movement time t2) may be calculated based on the designated in-position width, movement command 9, speed pattern parameter 7 and servo model, or movement Alternatively, the command payout time Tsi obtained using only the command 9 and the speed pattern parameter 7 may be used.

Two types of speed patterns (reference speed pattern P1 and second speed pattern P2) are selected. However, the selection of speed patterns is not limited to two types, and three or more types of patterns may be compared.
When the movement command in one block is not a single axis movement but a multiple axis movement, the movement command 9 from the machining program 1 may be regarded as a multiple axis movement command, and the speed pattern may be changed for each axis. .
When the multi-axis movement command is an interpolation command, the speed pattern may be changed only when the speed pattern can be changed for all axes.

  Hereinafter, as a specific example of the calculation of the reference position error 11 by the position error calculation unit 3, a case where the reference speed pattern P1 is a triangle command and the reference position error 11 is a droop amount Dr at the command payout time Tsi will be described.

In this case, since the command payout time Tsi is a time when the command in-position width becomes “0”, the start point parameter 8 is the command in-position width, and the index value Dsi is a parameter set by the user.
First, when the transfer function of the servo control unit 6 is a first-order lag system, the transfer function G (s) of the servo control unit 6 is expressed by the following equation (1) using the Laplace operator s and the proportional gain Kp. Is done.

  G (s) = Kp / (s + Kp) (1)

Here, the movement distance of the movement command 9 commanded by the machining program 1 is D, and the reference speed pattern parameter of the reference speed pattern P1 is set by the command acceleration α * (or the time constant (acceleration time) and the command speed V *. The reference position error 11 can be calculated as the droop amount Dr at the command payout time Tsi when the index value Dsi is “0”.
The droop amount Dr is expressed by the difference between the current position 12 and the position command 14 calculated from the servo control unit 6, and specifically, is calculated by the following equation (2).

  Dr = α * / (Kp × Kp) × {1-2exp (−Kp × Tsi / 2) + exp (−Kp × Tsi)} (2)

  The command payout time Tsi is a time at which the value obtained by integrating the speed command in the time axis direction and the movement distance D become equal. Specifically, using the command acceleration α *, the following equation (3) Calculated by

  Tsi = √ (4D / α *) (3)

The starting point parameter 8 used for the calculation of the reference position error unit 3 may be an in-position width or other values in addition to the command in-position width as the type of index.
The index value may be set as a parameter in advance or may be commanded for each movement command 9 in the machining program 1.

For example, by instructing the index value Di as the in-position width in the machining program 1 and performing in-position control, the movement time in the machining program 1 can be shortened most.
However, in actuality, specifying the in-position width for each movement command 9 of the machining program 1 requires a lot of labor for the operator, so that the in-position width is set only for a necessary part of the machining program 1. It is set.

Further, the reference position error 11 calculated by the reference position error unit 3 may be the in-position width or the command in-position width used for the start point parameter 8 or a value different from the start point parameter 8. May be the reference position error 11.
For example, when the start point parameter 8 is an in-position width, the reference position error 11 may be set as an inward amount E (trajectory error amount) at a corner portion in the reference speed pattern P1.

Here, the inward turning amount E at the corner is an error between the command path and the servo path at the corner (the joint between the command path and the next command path), and the point where the path is closest to the corner, Is the distance between.
Hereinafter, the movement trajectory of the corner portion will be described as an example of the effect of the first embodiment of the present invention with reference to FIGS.

  3 and 5 are explanatory diagrams showing the relationship between the command locus (corresponding to the movement command 9) and the movement locus in the first embodiment of the present invention, respectively. First, the movement command 9a is commanded in the x-axis direction. After that, when the movement command 9b is commanded in the y-axis direction, the command trajectory on the xy plane (movement commands 9a and 9b corresponding to the first and second blocks) (refer to the one-dot chain line arrow) and the reference speed A movement trajectory P1xy (see the two-dot chain line) in the pattern P1 and a movement trajectory P2xy (see the solid line) in the second speed pattern P2 are shown.

FIG. 3 shows a movement locus when the parameter of the next block movement command start point 13 is the in-position width of the index value Di (see FIG. 4), and FIG. 5 shows the start of the next block movement command. The movement trajectory when the parameter of the point 13 is an inward amount at the corner portion of the index value E is shown.
4 and 6 are explanatory diagrams showing time waveforms in the respective movement commands shown in FIGS. 3 and 5, where the horizontal axis represents time t, the vertical axis represents speeds Vx and Vy, and the upper stage represents the x axis. The time waveform of the velocity Vx in the direction and the time waveform of the velocity Vy in the y-axis direction are shown in the lower part.

4 and 6, the time waveform P1a and the time response waveform of the servo motor 50 when the reference speed pattern P1 (refer to the alternate long and short dash line) is a triangle command with respect to the movement command 9a of the first block. P11a, a time waveform P2a when the second speed pattern P2 (see solid line) is a rectangular wave command, and a time response waveform P21a of the servo motor 50 are shown.
4 and 6, the time waveform P1b and the time of the servo motor 50 when the reference speed pattern P1 (refer to the alternate long and short dash line) is a triangle command with respect to the movement command 9b of the second block. A response waveform P11b, a time waveform P2b when the second speed pattern P2 (see solid line) is a rectangular wave command, and a time response waveform P21b of the servo motor are shown.

  As shown in FIG. 5, the inward turning amount E at the corner portion corresponds to a radius when a circle (see a broken line) in contact with the movement path is drawn with the corner portion of the movement command 9a and the movement command 9b as the center of the circle. To do.

  Here, the droop amounts in the x-axis direction and the y-axis direction of the first block are Drx1 and Dry1, the movement amounts in the x-axis direction and the y-axis direction of the second block are Hx2 and Hy2, and the inward rotation amount E at the corner portion Can be calculated by the following equation (4).

  E = Min {√ ((Drx1 + Hx2) ^ 2 + (Dry1 + Hy2) ^ 2)} (4)

However, in Formula (4), Min {} represents the minimum value in {}.
In FIG. 4, when the command speed pattern is the reference speed pattern P1, the command start time of the time waveform P1b of the movement command 9b of the second block is the droop amount Dr and the in-position width of the time response waveform P21a of the servo motor 50. Time Tm1 when Di becomes equal.
On the other hand, in FIG. 4, when the command speed pattern is the second speed pattern P2, the command start time of the time waveform P2b of the movement command 9b of the second block is the droop amount Dr of the time response waveform P2a of the servo motor 50. And the in-position width Di become equal to time Tm2, and the movement time in the second speed pattern P2 is shorter than the movement time by the two-block movement command 9b in the reference speed pattern P1. Only shortened.

Further, as shown in FIG. 3, the movement locus P2xy (see the solid line) in the second velocity pattern P2 is inside the movement locus P1xy (see the two-dot chain line) in the reference velocity pattern P1, and the velocity pattern is changed. It turns out that the amount of inward corners increases.
On the other hand, in FIG. 6, since the in-position width Di2 in the second speed pattern P2 is adjusted so that the inward rotation amount E (see FIG. 5) at the corner is constant, the second speed pattern The in-position width Di2 when using P2 satisfies the relationship Di2 <Di.

Therefore, at time Tm21 when the time response waveform P21a of the servo motor 50 becomes equal to the in-position width Di2, the movement command P21b for the next block is started.
As a result, as shown in FIG. 5 and FIG. 6, the shortening time Ts2 of the moving time when the reference position error is the inner turning amount E at the corner portion is shortened when the in-position width is the same in each speed pattern. Although slightly shorter than the time Ts1 (see FIGS. 3 and 4), the same trajectory error as that of the conventional movement path can be maintained.

Further, when the trajectory error is the inward amount E at the corner portion, the inner amount E at the corner portion may be approximated as shown in FIG.
In FIG. 7, the inward turning amount E at the corner is a short movement command distance (or a long movement command distance or an average distance between W1 and W2) of the distances W1 and W2 of the two sides forming the corner. Is a corner portion having a side length W, and is approximated by the following equation (5).

  E = Wcos (φ / 2) (5)

However, in Formula (5), (phi) is a corner angle obtained by two movement commands which form a corner.
Here, the distance W1 in the x-axis direction corresponds to the droop amount Drx1 (or command in-position width and in-position width) of the first block at the next block movement command start point 13, and the distance W2 in the y-axis direction is This corresponds to the movement amount Hy2 of the second block when the movement command of the first block is completed.

  For example, when the start point parameter 8 in a certain speed pattern is the in-position width of the index value Di, the movement start point control unit 4 determines the deviation between the command end point position (target position) and the current position 12. Control is performed so that the next block movement command start point 13 is set to the time point when the index value Di or less is reached.

The movement start point control unit 4 is not limited to distance control, and may be time control. For example, when the start point parameter 8 is a command in-position width of the index value Dsi, the movement start point control unit 4 The command payout time Tsi may be calculated using the speed pattern variable 10 and the control may be executed to start the next block after the elapse of time from the movement start time to the command payout time Tsi.
If the position error calculation unit 3 is not used, the index for determining the next block movement command start point 13 and the value of the index may be used as the start point parameter 8 in the determined speed pattern.

Further, the internal index used when controlling the block movement command start point 13 is not in the same format as the reference position error 11, and a value calculated from the reference position error 11 may be used.
For example, when the reference position error 11 is the inward amount E at the corner portion, the in-position width is an internal index so that the movement path moved with the determined speed pattern becomes the inward amount E at the corner portion. You may adjust as follows.
In addition, the conversion process from the index at the reference position error 11 to the internal index may be executed by the movement start point control unit 4 or the position error calculation unit 3.
Therefore, the movement time can be shortened by changing the speed pattern while maintaining the accuracy at the command end point position within the range of the desired accuracy.

  As described above, according to the first embodiment of the present invention, a moving command 9 with acceleration / deceleration is given to a moving body having a driving device such as a servo motor 50, which becomes a reference for moving the moving body. In the numerical controller 100 that performs control according to the reference speed pattern P1 that is a speed pattern and the second speed pattern P2 that is a speed pattern different from the reference speed pattern P1, the reference speed pattern P1 and the second speed pattern A speed pattern determination unit 2 that compares the movement times t1 and t2 of the moving body with respect to P2 and determines the speed pattern variable of the speed pattern with the shorter movement time as the control speed pattern variable 10; A position error calculator 3 for calculating a reference position error 11 based on the reference speed pattern P1, and a speed pattern corresponding to the control speed pattern variable 10 The movement start point control unit 4 for controlling the next block movement command start point 13 of the moving body, the movement command 9 and the control command so that the position error when the moving body operates in accordance with the reference position error 11 An acceleration / deceleration control unit 5 is provided which outputs a position command 14 for a moving body using the speed pattern variable 10 and the next block movement command start point 13 as input information.

The position error calculation unit 3 calculates a reference position error 11 when the reference speed pattern P1 is used, and the movement start point control unit 4 starts the next block movement command of the moving body based on the reference position error 11. Adjust point 13.
As described above, by using the position error calculation unit 3 as a constituent element, it is possible to shorten the movement time while maintaining the accuracy at the command end point within the range of desired accuracy.
This effect is particularly remarkable when the velocity pattern is a rectangular wave command with the shortest movement time.

  In addition, a command other than the movement commanded after the movement command 9 in accordance with the change of the speed pattern (for example, S code (rotational speed function), T code (type function), M code (auxiliary function), etc. in a machine tool)) The timing for executing S, T, and M code is also changed, and the timing for executing S, T, and M code is delayed by the delay time Td to adjust the timing for executing S, T, and M code. Thus, it may be executed at the same position as the locus position in the conventional control.

  Here, when the delay time Td operates in the second speed pattern P2 using the trajectory position θm and the time Tm when the S, T, and M codes are executed when operating in the reference speed pattern P1. If the time when the locus position when Td = 0 is θm (or closest) is Tm2, the following equation (6) is given.

  Td = Tm−Tm2 (6)

Each time Tm, Tm2 in the equation (6) and the locus position θm at the time of execution of the S, T, M code are obtained from each speed pattern, the movement command 9 and the transfer function G (s) of the servo control unit 6. Can be obtained analytically.
Further, the trajectory error may be set by multiplying the reference position error 11 during operation with the reference speed pattern P1 by an adjustment coefficient.

Embodiment 2. FIG.
In the first embodiment (see FIG. 1), the speed pattern determination unit 2 uniquely determines the control speed pattern variable 10 based on the movement command 9 and the speed pattern parameter 7. As described above, the speed pattern selection unit 21 and the speed pattern change unit 22 are provided in the speed pattern determination unit 20, and the control speed pattern variable 23 is updated and set so that the maximum acceleration αmax of the moving body reaches the allowable acceleration αk. Also good.

The second embodiment of the present invention will be described below with reference to FIG.
FIG. 8 is a block diagram showing the main part of the NC processing unit of the numerical controller according to Embodiment 2 of the present invention, and shows the functional configuration of the speed pattern determining unit 20.
In FIG. 8, the speed pattern determination unit 20 is based on the movement command 9 and the speed pattern parameter 7, and the speed pattern selection unit 21 determines the control speed pattern variable 10 in the same manner as described above, and the movement command 9 and the control speed pattern variable. 10 and a speed pattern changing unit 22 that determines the control speed pattern variable 23 after the update setting.

  In this case, the speed pattern changing unit 22 in the speed pattern determining unit 20 is configured so that the maximum acceleration αmax reaches the allowable acceleration αk for a short movement command 9 in which the acceleration α does not sufficiently reach the allowable acceleration αk. By updating the control speed pattern variable 23, the travel time can be further shortened.

  That is, the control speed pattern variable 10 output from the speed pattern selection unit 21 in the speed pattern determination unit 20 includes the command acceleration α *, and the speed pattern change unit 22 uses the control speed pattern variable 10 as input information. When the speed pattern corresponding to the control speed pattern variable 10 accompanies acceleration / deceleration of the moving body, the command acceleration α * which is the control speed pattern variable 10 is updated, and the acceleration α of the servo motor 50 (drive device) is The command acceleration α * is increased until it coincides with the allowable acceleration αk, and the control speed pattern variable 23 that is faster than the control speed pattern variable 10 is updated and output.

At this time, in the control speed pattern variable 23 that is faster than the control speed pattern variable 10, the command acceleration α * increases (or the acceleration α rises sharply) when the speed pattern is S-shaped acceleration / deceleration. Corresponds to the speed pattern variable for character acceleration / deceleration.
When the speed pattern is a linear acceleration / deceleration command, the control speed pattern variable 23 corresponds to a speed pattern variable in a linear acceleration / deceleration command having a large command acceleration α *.

Further, when the speed pattern is a rectangular wave command, the control speed pattern variable 23 corresponds to a speed pattern variable in a rectangular wave command having a large command speed V *.
Since the fast speed pattern has a larger acceleration α than the servo (time constant) adjusted speed pattern, the range of the movement command 9 that can be used becomes narrow.

Next, the update setting process of the control speed pattern variable 23 by the speed pattern update unit 22 will be described with reference to the flowchart of FIG.
First, the control speed pattern variable 10 determined by the speed pattern selection unit 21 and the movement command 9 are read (step 700), and the moving object is read using the servo model, the movement command 9 and the control speed pattern variable 10. Is calculated (step 701).

  Subsequently, it is determined whether or not the maximum acceleration αmax matches the allowable acceleration αk (step 702). If it is determined that αmax <αk (that is, NO), the control speed pattern variable 10 is updated to the increasing side. (Step 703), the processing returns to the calculation processing (Step 701) of the maximum acceleration αmax.

Thereafter, in step 702, the processing of steps 701 to 703 is repeatedly executed until the condition of αmax = αk is satisfied.
If it is determined in step 702 that αmax = αk (that is, YES), the latest value of the control speed pattern variable 10 is determined as the updated control speed pattern variable 23 (step 704), and FIG. The processing routine ends.

Note that the maximum acceleration αmax calculated in step 701 is obtained, for example, by differentiating the ramp response of the servo model when the speed pattern is a rectangular wave command.
Further, the processing in steps 701 to 703 may be repeatedly executed n times (n is a natural number) or less.

  Further, the update rule in step 703 is an update rule in which the command acceleration α * is increased according to the maximum acceleration αmax when the speed pattern defined by the control speed pattern variable 10 is a triangle command. Good.

Further, the update rule in step 703 may be an update rule in which the command speed V * is increased in accordance with the maximum acceleration αmax when the speed pattern is a rectangular wave command.
In this case, in FIG. 8, the control speed pattern variable 10 includes a command speed V *, the speed pattern determination unit 20 includes a speed pattern update unit 22 that updates the command speed V *, and the speed pattern update unit 22 When the speed pattern corresponding to the control speed pattern variable 10 does not accompany acceleration / deceleration of the moving body, the command speed V * is increased until the acceleration α of the servo motor 50 (drive device) matches the allowable acceleration αk.

Furthermore, when the speed pattern defined by the control speed pattern variable 10 is a triangle command, the update rule in step 703 is an update rule that multiplies the command acceleration α * by a constant corresponding to the maximum acceleration αmax. If the speed pattern is a rectangular wave command, an update rule for multiplying the command speed V * by a constant corresponding to the maximum acceleration αmax may be used.
As a result, a sufficient acceleration α can be obtained even with respect to the movement command 9 in which the acceleration α does not become sufficiently large, and the moving body is moved in a movement time shorter than the movement time in the first embodiment described above. Can do.

Embodiment 3 FIG.
In the second embodiment, the updated control speed pattern variable 23 is determined in consideration of the case where the moving body has only a single system. However, the case where the moving body has a plurality of systems capable of operating in parallel is considered. Then, for example, as shown in FIG. 10, an applied system selection unit 30 may be provided that uses the multi-system machining program 15 as input information and the machining program 1 as output information.
Hereinafter, a numerical controller according to Embodiment 3 of the present invention will be described with reference to FIGS.

In general, in a multi-system system (numerical control apparatus) in which a plurality of systems capable of operating in parallel exists, an inter-system waiting command is applied to synchronize the systems.
Inter-system wait control using such inter-system wait commands is used for simultaneous cutting commands, superposition commands, synchronization commands (spindle synchronization, synchronous taps, etc.), interference prevention, etc. The control is such that the next command is not executed until the system enters the waiting state.

  In the third embodiment of the present invention, in the multi-system system that performs inter-system wait control, by providing a processing means that compares and determines the actual required time between the wait instructions, the above-described first and second embodiments. By selecting a system for executing the speed pattern update process and providing a processing means for comparing and determining the actual required time between the waiting commands, an unnecessary speed pattern change is avoided.

FIG. 10 is a block diagram showing the main part of the NC processing unit of the numerical controller according to Embodiment 3 of the present invention. Components similar to those described above (see FIG. 1) are denoted by the same reference numerals as above. Detailed description is omitted.
In this case, it is assumed that the moving body having the numerical controller 100 and the servo motor 50 (see FIG. 1) includes a plurality of systems Qi that operate in parallel by inter-system waiting control based on the multi-system machining program 15.

In FIG. 10, the numerical control device including a plurality of systems includes an applied system selection unit 30 that uses the multi-system machining program 15 as input information and the machining program 1 as output information.
The applied system selection unit 30 includes a waiting section determination unit 24, a determination index calculation unit 25, and an application system determination unit 26.
That is, in this case, the multi-system machining program 15 → the applied system selection unit 30 → the machining program 1 to be applied, and one numerical control device 100 in FIG. 1 is applied.
For example, the applied system selection unit 30 selects the applied system B * based on the waiting section A * of the multi-system program 15, and the numerical control device 100 applies only the movement command in the system determined to be applied to the above-described movement command. The processing of the first and second embodiments is executed.
Note that the change of the speed pattern means a change from the reference speed pattern P1 to the second speed pattern P2.
The waiting section determination unit 24 determines a waiting section A, which is a command block between waiting instructions for inter-system waiting control, using the multi-system machining program 15 included in the machining program 1 (see FIG. 1) as input information.

The determination index calculation unit 25 calculates a determination index F as to whether or not to execute the speed pattern change process in each system Qi in the waiting section A using the waiting section A as input information.
The applied system determination unit 26 determines a system to which the speed pattern changing process is applied according to the determination index F, and outputs the selected applied system B as the machining program 1.

Next, an applied system determination process according to Embodiment 3 of the present invention that outputs the applied system B using the multi-system machining program 15 as input information will be described with reference to the flowchart of FIG.
In FIG. 11, first, the waiting section determination unit 24 analyzes a waiting instruction in all the systems Qi based on the multi-system machining program 15 that performs waiting control between each of a plurality of systems, and determines a waiting section A. (Step 901).

Next, the determination index calculation unit 25 obtains an applicability determination index F in each system Qi for each waiting section A (step 902).
Finally, the applied system determination unit 26 determines the applied system B for each waiting section A based on the determination index (step 903), and ends the processing routine of FIG.

Note that the waiting section A determined in step 901 may be a command block in a section from a waiting command for aligning the timings of all systems Qi to a waiting command for aligning the timings of all systems Qi.
In addition, the waiting section A may be a command block in a section from a waiting command that aligns the timings of a plurality of systems Qj that are not all systems Qi to a waiting command that aligns the timings of a plurality of systems Qj that are not all systems Qi.

Further, the execution start command and the execution end command of the machining program 1 may be set in the start block or the end block of the waiting section A.
Further, the determination index F calculated in step 902 may be a waiting time in each system Qi or may be an actual required time.
The actual required time is the time required for each system Qi other than the waiting command in the waiting section A, and may be a value calculated based on the machining program 1, or a machining program to which the reference speed pattern P1 is applied. The value measured by executing 1 may be used.

  Further, the determination of the applied system B in step 903 may be determination based on the determination index F or determination based on direct designation by the user.

Next, the relationship between the waiting section A and the application system B will be described with reference to the explanatory diagram of FIG.
In FIG. 12, a time t is plotted on the vertical axis, and a system composed of three systems (first system Q1, second system Q2, and third system Q3) is shown, and three waiting sections A1 to A3 (broken lines) In addition, each of the application systems B1 to B3 is selected with respect to each other (refer to the dotted line).

  In each waiting section A1 to A3 in FIG. 12, the vertical block lengths of the applicable systems B1 to B3 and the non-applicable systems C11, C12, C21, C31, and C32 are the same as those in the first system Q1 to the third system Q3. The execution time for commands other than waiting is shown.

As the application systems B1 to B3, the system of the block having the longest actual required time in each waiting section A1 to A3 is selected.
Non-applicable systems C11, C12, C21, C31, and C32 are systems of blocks that are not selected as an applicable system in each of the waiting sections A1 to A3.

  As apparent from FIG. 12, in the waiting section A1, the block of the second system Q2 among the three systems has the longest actual required time, so the block of the second system Q2 is selected as the applied system B1, The two blocks become non-applicable systems C11 and C12.

  Further, in the waiting section A2, only the first system Q1 and the second system Q2 are waiting by the waiting command, and the actual required time of the block of the second system Q2 is the longest. It is selected as B2, and the other block is a non-applicable system C21.

In addition, the waiting section A3 (see the one-dot chain line) includes the waiting section A2 (see the broken line), and each block of the first system Q1 and the second system Q2, that is, the applicable system B3 and the non-applicable system C31, Since it is executed after the section A2, the calculation of the actual required times of the first system Q1 and the second system Q2 includes the block portion of the waiting section A2.
Accordingly, in the waiting section A3, the block of the first system Q1 excluding the portion of the waiting section A2 becomes the application system B3.
In addition, when the sub system | strain is used in each waiting area A1-A3, you may extend the application range of above-mentioned Embodiment 2 to a sub system | strain.

  As described above, according to the third embodiment of the present invention, when applied to a moving body composed of a plurality of systems, an increase in waiting state, excitation of vibration, It is possible to prevent the deterioration of accuracy due to.

It is a block diagram which shows schematic structure of NC processing part of the numerical control apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the determination process of the speed pattern variable for control by Embodiment 1 of this invention. It is explanatory drawing which shows a movement locus | trajectory when the locus | trajectory error by Embodiment 1 of this invention is made into the same in-position width | variety. It is explanatory drawing which shows a time waveform and shortening time when the locus | trajectory error by Embodiment 1 of this invention is made into the same in-position width | variety. It is explanatory drawing which shows a movement locus | trajectory at the time of making the locus | trajectory error by Embodiment 1 of this invention into the amount of inward rotation in a corner part. It is explanatory drawing which shows a time waveform and shortening time at the time of making the locus | trajectory error by Embodiment 1 of this invention into the amount of inner circles in a corner part. It is explanatory drawing which shows the case where the inner circle amount in a corner part is approximated for the locus | trajectory error by Embodiment 1 of this invention. It is a block diagram which shows the principal part of NC processing part of the numerical control apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the update process of the speed pattern variable for control by Embodiment 2 of this invention. It is a block diagram which shows the principal part of NC processing part of the numerical control apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the applicable system discrimination | determination process by Embodiment 3 of this invention. It is explanatory drawing which shows the relationship between the waiting area by Embodiment 3 of this invention, and an applicable system | strain.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Processing program, 2, 20 Speed pattern determination part, 3 Position error calculation part, 4 Movement start point control part, 5 Acceleration / deceleration control part, 6 Servo control part, 7 Speed pattern parameter, 8 Start point parameter, 9, 9a, 9b Movement command, 10 Control speed pattern variable, 11 Reference position error, 12 Current position, 13th next block movement command start point, 14 Position command, 21 Speed pattern selection unit, 22 Speed pattern update unit, 23 Updated control Speed pattern variable, 24 waiting section determination unit, 25 determination index calculation unit, 26 application system determination unit, 30 application system selection unit, 50 servo motor, 100 numerical control device, A, A1-A3 waiting section, B, B1- B3 Applicable system, Di in-position width, Di2 Trajectory error of inward rotation amount at corner part In-position width, Dsi command in-position width, inner amount at E corner, F determination index, P1 reference speed pattern, P2 second speed pattern, P1xy movement path of xy plane with reference speed pattern, P2xy second Xy plane trajectory with the following speed pattern, P1a, P1b movement command time waveform with reference speed pattern, P2a, P2b movement command time waveform with second speed pattern, P11a, P21a Servo with reference speed pattern Motor time response waveform, P11b, P21b Servo motor time response waveform in the second speed pattern, movement command start time of the next block in the Tm1 reference speed pattern, Tm2, Tm21 Next in the second speed pattern When the block movement command start time and Ts1 reference position error are in-position width Shortening time, Ts2 reference position errors shortening time with respect to the inward turning of the corner portions a, Q1 to Q3 plurality of systems, t1 reference travel time, t2 the second movement time.

Claims (4)

A moving command with acceleration / deceleration is given to a moving body having a driving device, and a reference speed pattern that is a reference speed pattern by which the moving body can move is different from the reference speed pattern. In the numerical control apparatus that performs control according to the speed pattern of 2,
A speed pattern determination unit that compares each moving time of the moving body with respect to the reference speed pattern and the second speed pattern and determines a speed pattern variable of a speed pattern having a shorter moving time as a control speed pattern variable When,
A position error calculator for calculating a reference position error based on the movement command and the reference speed pattern;
Start of movement for controlling the next block movement command start point of the moving body so that the position error when the moving body operates according to the speed pattern corresponding to the control speed pattern variable matches the reference position error. A point controller;
An acceleration / deceleration control unit that outputs a position command to the moving body, using the movement command, the control speed pattern variable, and the next block movement command start point as input information;
The position error calculation unit calculates the reference position error when using the reference speed pattern,
The numerical controller according to claim 1, wherein the movement start point control unit adjusts a next block movement command start point of the moving body based on the reference position error. The control speed pattern variable includes a commanded acceleration,
The speed pattern determination unit includes a speed pattern update unit that updates the command acceleration,
The speed pattern update unit increases the commanded acceleration until an acceleration of the driving device matches an allowable acceleration when a speed pattern corresponding to the control speed pattern variable is accompanied by acceleration / deceleration of the moving body. The numerical control apparatus according to claim 1, wherein The control speed pattern variable includes a command speed,
The speed pattern determination unit includes a speed pattern update unit that updates the command speed,
The speed pattern update unit increases the command speed until an acceleration of the driving device matches an allowable acceleration when a speed pattern corresponding to the control speed pattern variable does not accompany acceleration / deceleration of the moving body. The numerical control apparatus according to claim 1. The mobile body and the numerical control device are composed of a plurality of systems that operate in parallel by inter-system waiting control based on a multi-system machining program,
The numerical control device comprising the plurality of systems includes an applied system selection unit that selects an applied system to be controlled from the plurality of systems based on the multi-system machining program,
The application system selection unit is
With the multi-system machining program as input information, a waiting section determination unit that determines a waiting section that is a command block between waiting instructions for inter-system waiting control, and
A determination index calculation unit that calculates a determination index as to whether or not to change a speed pattern in each system in the waiting section, using the waiting section as input information;
An applied system determining unit that determines a system to which a speed pattern change process is applied according to the determination index as the applied system from the plurality of systems. The numerical control device according to any one of the above.

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