JP2007164509A - Numeric controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a numeric controller achieving stable movement even when blocks for commanding minute movement are continued. <P>SOLUTION: A temporary program which does not perform axial movement is executed. In the execution of the temporary program, the number N of blocks to be prefetched within a time for current distribution processing is obtained (S15), distance of a movement command in each block is integrated until the number N of blocks to be prefetched is reached to obtain an integrated moving distance L (S7 to S10). A possible output velocity Va is obtained from the integrated moving distance L (S11). This is repeated and a minimum possible output velocity Va is obtained (S12 and S13). The smaller one out of the minimum possible output velocity and a velocity command commanded by a program is used as a velocity command when executing the program (S16 to S19). Thus, even when an small of movement is commanded in each block, the movement does not stop but stable movement is achieved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a numerical controller that controls various machines such as machine tools.

In the numerical control device, a pre-read process is performed in which command blocks instructed by the machining program are read one by one, interpreted, and converted into executable data. Based on the execution data obtained by the pre-reading process, the interpolation processing unit performs interpolation distribution processing and outputs a movement command to the control unit of each axis servo motor.
However, if the pre-reading process for the next block command is not completed despite the completion of the interpolation distribution process, such as when a short distance movement command is continued, the interpolation distribution process cannot be performed and the operation May stop.

  When the command speed is constant and a short distance movement command block continues, the processing time for moving the movement distance commanded by one block at the program command speed is calculated by dividing the command movement distance by the command speed. It's time. If this time is smaller than the minimum allowable movement time required for the preprocessing of the next block, the movement of the motor is stopped, resulting in intermittent movement.

  Therefore, the invention described in Patent Document 1 calculates the allowable maximum feed speed by dividing the command travel distance of the block by the permissible minimum travel time, and when the feed speed commanded by the machining program is larger than the permissible maximum feed speed. The interpolation processing is performed with the allowable maximum feed speed obtained from the actual feed speed.

However, this method has a problem that the speed changes for each block and smooth movement is impossible. Therefore, the allowable minimum movement time that can be moved without stopping when moving by the movement distance commanded in one block corresponding to the prefetch processing time of the prefetch processing section is set to ta, and the block n set in advance in the prefetch processing section is set. Is read from the program, and the allowable maximum feed speed Va from the total movement distance L and the speed control coefficient K is Va = (L / (ta · n)) · K
When the command feed speed F is larger than the permissible maximum feed speed Va, a method is proposed in which the actual feed speed is set to the permissible maximum feed speed Va (see Patent Document 2).

JP-A-7-191728 Japanese Patent No. 3188396

However, since the number of prefetch blocks varies depending on the processing time of the block being executed, there is a problem that it is difficult to appropriately determine the number of blocks designated in advance.
Accordingly, an object of the present invention is to provide a numerical control device that enables smooth machining by smoothly moving without stopping movement even in a machining program in which blocks of movement commands for a short distance are continuous. It is in.

  The present invention includes provisional program execution means for executing a machining program without moving the axis, and the provisional program execution means executes the machining program, and the amount of movement for each number of blocks that can be prefetched during execution of each block of the machining program. A travel distance calculation means for summing up, a possible output speed calculation means for obtaining a speed that can be output for each number of prefetch blocks from the travel amount obtained by the travel distance calculation means and the distribution cycle of the numerical controller, and the output The actual machining speed calculation means for obtaining the lowest speed among the speeds obtained by the possible speed calculation means, the feed speed obtained by the actual machining speed calculation means and the program command speed are compared, and the program command speed is In the case of a larger value, there is a speed command adjusting means for replacing the programmed command speed with the lowest speed command obtained by the actual machining speed calculating means. It is obtained by allowing the execution of actual machining program with the shaft moves at a speed command obtained in the temporary program executing means. In addition, each time the speed command is changed in the machining program, the speed command is replaced. Furthermore, a preset speed adjustment area is set, and the command speed is replaced for each set speed adjustment area.

  A stable movement can be realized without stopping the movement in a case where blocks for commanding a minute movement amount are continuous.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a principal block diagram of a numerical controller according to each embodiment of the present invention. The present invention is different from the conventional numerical control device in that it includes provisional program execution means. In each of the embodiments, a provisional program execution mode, that is, a selection switch 7 for selecting provisional program execution means and stable machining are provided. A speed calculation means 8 for obtaining a machining speed command for performing the above is added to the conventional numerical control device.

  In the conventional numerical control device, there is no selection switch 7 and speed calculation means 8, and the prefetch processing unit 2 prefetches block commands sequentially from the machining program 1 stored in the storage device, and interprets and executes the block commands. Create data. Based on the execution data created by the prefetch processing unit 2, the interpolation unit 3 performs interpolation distribution processing and distributes the movement command to the servo control units 4, 5, and 6 on the X, Y, and Z axes.

  In each of the embodiments, a temporary command for obtaining a speed command capable of executing a machining program and performing stable machining without outputting a movement command to the servo control units 4, 5, and 6 for the X, Y, and Z axes and moving the axes. A program execution unit is provided, and the temporary program execution unit includes the prefetch processing unit 2 and the speed calculation unit 8.

  When the temporary program execution mode is selected, the selection switch 7 is selected so as to connect the prefetch processing unit 2 and the speed calculation means 8, and the machining program 1 is temporarily executed. That is, the prefetch processing unit 2 sequentially reads blocks from the machining program 1 and converts them into execution data. The speed calculation means 8 obtains and stores a command speed capable of stable machining from the execution data. When the machining program is actually executed, the interpolation unit 3 executes the interpolation distribution process based on the stored command speed.

2 and 3 are flowcharts of processing executed by the numerical control device of the first embodiment as the speed calculation means 8 when the temporary program is executed.
When a temporary program execution command is input, the processor of the numerical controller first clears a register that accumulates command block lengths and clears a counter that counts the number of read blocks (step S1). Next, the machining program is read, and 1 is added to the counter of the number of read blocks (step S2). Then, the movement distances commanded by the read block are integrated to obtain an integrated movement distance L (step S3). Next, it is determined whether the number of read blocks has reached a preset number of prefetched blocks Ns (step S4). If not reached, the process returns to step S2 and the processes of steps S2 to S4 are repeatedly executed. If the read block command is not a movement command, the number of read blocks is not incremented by 1 in the counting counter.

  When the value of the counter that counts the number of read blocks has reached a preset number Ns, the number N of blocks that can be prefetched from the integrated movement distance L, the preprocessing time, and the program command speed determined in step S3 is calculated. It is obtained and stored in a register for storing the number of prefetchable blocks (step S5). That is, if the accumulated movement distance L is divided by the program command speed, the time required when the accumulated movement distance L is moved at the program command speed is obtained. If this time is divided by the preprocessing time of each block, a pre-readable block is obtained. The number N is obtained and stored in a register.

  Next, the maximum value that can be stored in the register A that stores the output speed is stored (step S6), the register that stores the integrated value of the command block length and the counter that counts the number of read blocks are cleared (step S7). The next block is read from the machining program, and 1 is added to the counter of the number of read blocks (step S8). In this case, if the block command is not a movement command, 1 is not added to the counter of the number of read blocks. The travel distance commanded in the read block is added to a register that stores the cumulative value of the command block length to determine the cumulative travel distance L (step S9). Further, it is determined whether the value of the counter for counting the number of read blocks has reached the number N of prefetchable blocks stored in the register, and further whether the program is finished (step S10). Initially, this register stores the number of prefetchable blocks N obtained in step S5, and the number of prefetchable blocks N is compared with the number of read blocks.

  If the value of the counter for counting the number of read blocks has not reached the number of pre-readable blocks N, the process returns to step S8 and the processes of steps S8 to S10 are repeatedly executed to update and calculate the integrated movement distance L. When the number of read blocks reaches the number N of prefetchable blocks or when the program ends, the output possible speed Va is obtained based on the integrated movement distance L (step S11). That is, the output possible speed Va is obtained by dividing the integrated movement distance L by the value obtained by multiplying the number of read blocks by the distribution period.

  Next, the value of the register A that stores the output possible speed is compared with the calculated output possible speed Va (step S12). If the output possible speed Va is smaller than the value of the register A, the output possible speed is stored in the register A. Va is stored (step S13). If the output possible speed Va is equal to or higher than the value of the register A, the value of the register A is not updated. Initially, since the maximum value is set in the register A in step S6, the output possible speed Va obtained in step S11 is stored in the register A.

  Then, it is determined whether or not the program is finished (step S14). If it is not finished, the number N of prefetchable blocks is obtained based on the current time required for distribution processing and the preprocessing time per block, stored in the register and updated. (Step S15). That is, the time required for the distribution processing of N blocks to be stored in the register before executing the processing of step S15 (N × distribution cycle time) is divided by the preprocessing time per block and stored in this register. Within the time required for the distribution interpolation processing for each command of the number of blocks, the number of prefetchable blocks is obtained, stored in the register and updated, and the new prefetchable block number N stored in this register is changed to the next prefetch block number. It is what.

  Thereafter, the process returns to step S7, and the above-described processing from step S7 onward is executed. In the determination processing in step S10, the prefetchable block number N and the prefetch block number stored in the register obtained in step S15 are determined. A comparative judgment will be made. In addition, the minimum value of the output possible speed Va obtained in step S11 is stored in the register A by the processing in steps S12 and S13.

  If it is determined in step S14 that the program has ended, the minimum output speed Va stored in the register A is compared with the program command speed (step S16). If the program command speed is small, the command speed F is set as the program command speed ( Step S17) If the minimum output possible speed Va is equal to or lower than the program command speed, the command speed F is set to the minimum output possible speed Va stored in the register A (Step S18). Then, the command speed F thus obtained is stored, and the temporary program process ends.

  When the machining program 1 is executed to actually perform machining (the selection switch 7 is connected to the interpolation unit 3), the processor of the numerical controller is obtained by the above-described temporary program process instead of the speed command commanded by the program. The interpolation distribution process is executed according to the stored command speed F.

  Since the interpolation distribution process is performed at the minimum output possible speed Va, the situation where the pre-read process is not in time and execution data is not created is avoided, and the machining is executed at a stable speed.

  In the first embodiment described above, an example in which one speed command F that can perform stable machining with respect to one machining program is shown. However, when the command speed changes in the middle of the machining program, a temporary program is executed. For each program speed command, a speed command capable of performing stable machining may be obtained for each program speed command, and the interpolation distribution process may be executed with the obtained speed command F. The process for obtaining the speed command F by the provisional program execution in the second embodiment is the same as that in the first embodiment as compared with the first embodiment, and the process shown in FIG. Is different. This different processing portion is shown in FIG.

  That is, in the second embodiment, the processing of FIG. 2 is performed after the processing of FIG. 2 is executed by the temporary program execution. Steps S10 and S14 are different from the first embodiment. Step S20 is added. Step S10 is changed to step S10 ′ to determine whether the number of prefetched blocks N has been reached and to determine whether a speed command change has been read, and whether step S14 has changed to step S14 ′, whether the program has ended or the speed command has been changed. In step S19, step S19 'is changed to step S19' so that it is replaced with a speed command capable of stable machining corresponding to the program command speed, and step S20 is added. If the program is not finished, the process proceeds to step S15.

As in the first embodiment, after executing the processing of step S1 to step S7, the block of the movement command is read until the number of prefetchable blocks N is reached or the block for which the speed command is made is read. And the movement distance is integrated to obtain the movement distance L (steps S8 to S10 ′).
When the movement command block is read until the number of prefetchable blocks N is reached or the block for which the speed command is issued is read, the output possible speed Va is obtained and compared with the value of the register A as in the first embodiment. When the output possible speed Va is smaller than the value of the value, the output possible speed Va is stored in the register A (steps S11 to S13). Then, it is determined whether the command of the read block is a program end or a block for changing the speed command (step S14 '). If the block is not a program end or a block for changing the speed command, the process proceeds to step S15, and a pre-readable block The number N is updated, and the process returns to step S7.
Thereafter, the processes of steps S7 to S15 are repeated, and the minimum value of the output possible speed Va is stored in the register A within the same speed command.

When it is determined in step S14 'that the speed command block has been read and the speed command has been changed, the processing of steps S16 to S18 is executed as in the first embodiment, and the output possible speed stored in the register A Va or the smaller one of the program command speeds is adopted and stored in the memory as corresponding to the program speed command (step S19 ′).
Thereafter, it is determined whether the program is finished (step S20). If the program is not finished, the process proceeds to step S15. If the program is to be terminated, the provisional program processing is terminated after the processing from step S14 'to steps S16 to S20.

  Next, a third embodiment will be described. In the third embodiment, even in the machining program in which the same speed is commanded, when the minute blocks are continuous, the integrated movement distance of the prefetch block is shortened, and the speed command F required in the first embodiment is very slow. There is a case. Therefore, the area where the speed command is changed to a speed command capable of stable machining is designated by the program command or parameter command, and the speed command changing process is performed only in this area. A region to be changed to a speed command is designated by a sequence number as, for example, Nxx to Nyy.

  5 and 6 are flowcharts showing the temporary program processing of the third embodiment. When the processor of the numerical controller starts the temporary program process, it first clears the register that accumulates the command block length and clears the counter that counts the number of read blocks (step T1). Next, the machining program is read (step T2), and it is determined whether the sequence number of the read block is a sequence number set to start the speed command adjustment process (step T3). Thereafter, steps T2 and T3 are repeated until the sequence number set to start the speed command adjustment process is read.

  When the sequence number set to start the speed command adjustment process is read, 1 is added to the counter of the number of read blocks (step T4). Then, the movement distances commanded by the read block are integrated to obtain an integrated movement distance L (step T5). Next, it is determined whether the number of read blocks has reached the preset number Ns of pre-read blocks (step T6). If not, the next block is read from the machining program (step T7), and the process returns to step T4. Steps T4 to T7 are repeatedly executed. When the value of the counter that counts the number of read blocks reaches a preset number Ns, as in the first embodiment, the integrated movement distance L obtained in step T5 and the preprocessing time of each block The number of prefetchable blocks N is obtained from the program command speed and stored in a register for storing the number of prefetchable blocks (step T8).

  Next, the maximum value that can be stored in the register A that stores the output possible speed is stored (step T9), the register that stores the integrated value of the command block length and the counter that counts the number of read blocks are cleared (step T10). The next block is read from the machining program, and 1 is added to the counter of the number of read blocks (step T11). The travel distance commanded in the read block is added to a register that stores the cumulative value of the command block length to obtain the cumulative travel distance L (step T12). Further, it is determined whether the value of the counter for counting the number of read blocks has reached the number N of pre-readable blocks stored in the register, and further whether the block having the speed adjustment end sequence number has been read (step T13). Initially, this register stores the number of prefetchable blocks N obtained in step T8, and the number of prefetched blocks N is compared with the number of read blocks.

  If the value of the counter for counting the number of read blocks does not reach the number of pre-readable blocks N and if the block of the end sequence number is not read, the process returns to step T11 and the processes of steps T11 to T13 are repeated, and the integrated movement distance L Update and ask for. Then, when the number of read blocks reaches the number N of prefetchable blocks, or when reading the block of the end sequence number, the output possible speed Va is obtained based on the accumulated movement distance L as in the first embodiment ( In step T14), the value of the register A that stores the output possible speed is compared with the calculated output possible speed Va (step T15). If the output possible speed Va is smaller than the value of the register A, this output is possible to the register A. The speed Va is stored (step T16).

  Then, it is determined whether it is an end sequence number indicating the end of the program or the end of the speed adjustment area (step T17). If it is neither the end of the program nor the end sequence number, the number N of prefetchable blocks is the same as in the first embodiment. Is stored in the register and updated (step T18), the process returns to step T10, and the above-described processing from step T10 onward is executed.

  When it is determined in step T17 that the block having the end sequence number has been read, the minimum output possible speed Va stored in the register A is compared with the program command speed as in the first embodiment (step T19). If the program command speed is low, the command speed F is set as the program command speed (step T20). If the minimum output speed Va is less than the program command speed, the minimum output speed Va stored in the register A is stored in the register A. (Step T21). Then, the command speed F thus obtained is stored as a speed command for the speed adjustment area (step T22). If the program is not finished (step T23), the process returns to step T1 to execute the above-described processing.

It is a principal part block diagram of the numerical control apparatus of each embodiment of this invention. It is a part of flowchart of the temporary program process of the 1st Embodiment of this invention. FIG. 3 is a continuation of FIG. 2 in the flowchart of the temporary program process according to the first embodiment of this invention. It is a flowchart principal part of the temporary program process of the 2nd Embodiment of this invention. It is a part of flowchart of the temporary program process of the 3rd Embodiment of this invention. FIG. 10 is a continuation of FIG. 5 in the flowchart of the temporary program process according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing program 2 Prefetch processing part 3 Interpolation part 4 X-axis servo control part 5 Y-axis servo control part 6 Z-axis servo control part 7 Selection switch 8 Speed calculation means

Claims (3)

Provisional program execution means for executing the machining program without moving the axis,
The temporary program execution means executes a machining program, and moves distance calculation means for integrating movement amounts for each number of blocks that can be prefetched during execution of each block of the machining program;
Outputable speed calculation means for obtaining a speed that can be output for each number of the prefetch blocks from the movement amount obtained by the movement distance calculation means and the distribution cycle of the numerical control device;
Of the speeds determined by the output speed calculation means, an actual machining speed calculation means for obtaining the lowest speed;
The feed speed obtained by the actual machining speed calculation means is compared with the program command speed, and when the program command speed is large, the speed at which the program command speed is replaced with the lowest speed command obtained by the actual machining speed calculation means Command adjusting means,
A numerical control apparatus characterized by enabling execution of an actual machining program accompanied by axis movement by a speed command obtained by the temporary program execution means.   The numerical control device according to claim 1, wherein the temporary program execution unit executes the replacement of the speed command every time the speed command is changed in the machining program. The numerical controller according to claim 1, wherein the temporary program execution unit executes replacement of a command speed for each preset speed adjustment region.

Images