JP2016051290A - Numerical control apparatus, machine tool control system, numerical control method, and numerical control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a number of processes performed by a numerical control apparatus provided for each machine tool, and allow a lower-performance apparatus to be used as a numerical control apparatus.SOLUTION: A numerical control apparatus comprises: receiving means that sequentially receives in an execution order interpolated data for driving a driving section of a machine tool based on a processing program; a storing section that temporarily stores a predetermined amount of the interpolated data received by the receiving means; and interpolated data output means that sequentially reads the interpolated data from the storing section in the execution order, concurrently with the receiving means receiving the interpolated data, and outputs execution data based on the read interpolated data, to the driving section. The interpolated data is interpolated data that is processed in advance for speed adjustment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a numerical control device for a machine tool.

  Conventionally, there is an NC control method using an NC program as one of numerical control methods for machine tools. The user creates an NC program in order to instruct the machine tool to a target machining process. The NC program is a program having a code system such as a G code representing a movement command for a spindle or a tool post, a T code representing a calling command for a tool to be used, and an M code representing an auxiliary function command. A numerical control device (NC device) of a machine tool reads an NC program block by block and sequentially executes a plurality of commands while interpreting the command (NC code).

  In such a numerical control device, dedicated hardware is created for each machine tool, and there is a case where a CPU (Central Processing Unit) board or software is regenerated in order to cope with a specification change or version upgrade. is there.

  Thus, for example, a technique using a general-purpose product other than the peripheral device connection board has been proposed (Patent Document 1).

JP-A-9-34529

  However, even if a numerical control device is created using a general-purpose product, there is no change in providing a numerical control device that interprets the NC program and controls the machine tool for each machine tool.

  It is an object of the present invention to reduce the number of processes performed by the numerical control device provided for each machine tool as much as possible, and to use a device with lower performance as the numerical control device.

  A numerical control device according to one aspect of the present invention includes a receiving unit that sequentially receives interpolation data for driving a driving unit of a machine tool based on a machining program in an execution order, and an interpolation data received by the receiving unit. In parallel with the reception of the interpolation data by the receiving unit, the storage unit stores the fixed amount temporarily, sequentially reads the interpolation data from the storage unit in the execution order, and outputs the execution data based on the read interpolation data to the drive unit Interpolating data output means, wherein the interpolating data is interpolated data subjected to acceleration / deceleration processing in advance.

  The numerical control method according to another aspect is a numerical control method used in a numerical control device including a storage unit that temporarily stores a predetermined amount of interpolation data for driving a drive unit of a machine tool based on a machining program. In parallel with the reception step of receiving the interpolation data in the order of execution, and receiving the interpolation data in the reception step, the interpolation data is sequentially read out from the storage unit in the order of execution, and the execution based on the read interpolation data An interpolation data output step for outputting data to the drive unit, wherein the interpolation data is interpolation data for which acceleration / deceleration processing has been performed in advance.

  The numerical control program according to another aspect is a numerical control program used in a numerical control device including a storage unit that temporarily stores a predetermined amount of interpolation data for driving a drive unit of a machine tool based on a machining program. And receiving means for sequentially receiving the interpolation data in the order of execution; in parallel with reception of the interpolation data by the receiving means, the interpolation data is sequentially read out from the storage unit in the order of execution, and based on the read interpolation data A computer is made to function as an interpolation data output means for outputting execution data to the drive unit, and the interpolation data is interpolation data subjected to acceleration / deceleration processing in advance.

  According to this configuration, the numerical control device receives the interpolation data on which acceleration / deceleration processing has been performed in advance, so there is no need to perform NC program analysis, acceleration / deceleration processing, or the like. Accordingly, since the processing to be performed is less than that of the conventional numerical control processing, it is possible to use a CPU with lower performance. There is no need to arrange dedicated hardware for each machine tool as in the past, and interpolation data that has been subjected to acceleration / deceleration processing is created in advance, and the above numerical control device with low performance and low cost is provided for each machine tool. What is necessary is just to arrange. In other words, the processing that was conventionally performed by one dedicated hardware was distributed to the interpolation data generation device that generates the interpolation data subjected to the acceleration / deceleration processing and the numerical control device arranged in the machine tool. It will be. As a result of being distributed, as long as the numerical control device is connected to the interpolation data generation device via a LAN (Local Area Network) or the like so that the interpolation data can be received, it is not tied to the arrangement position of the interpolation data generation device. Thus, it becomes possible to freely determine the arrangement position of the numerical control device. Therefore, by using the numerical control device, it is possible to construct an appropriate system and an appropriate system.

  In the above numerical control apparatus, the interpolation data includes data indicating the moving speed of the machine tool, and includes an interrupt detection means for detecting an interrupt and an instruction indicated by the interrupt detected by the interrupt detection means. And a coefficient creating means for creating a coefficient representing a time-series change in the moving speed, wherein the interpolation data output means receives interpolation data corresponding to a moving amount corresponding to the coefficient from the storage unit. It is preferable that the execution data based on the read and read interpolation data is output to the drive unit.

  According to this configuration, an interrupt is detected, and the moving speed of the machine tool can be changed in accordance with an instruction indicated by the interrupt. Therefore, the change can be made for each numerical control device.

  Moreover, in the above-described numerical control device, when the interrupt detection unit detects an interrupt instructing the change of the moving speed, the coefficient creating unit determines from the moving speed when the interrupt is detected, after the instructed change. It is preferable to create the coefficient so that the speed gradually changes up to the moving speed.

  According to this configuration, when an instruction interruption to change the moving speed is detected, the moving speed is gradually changed to the instructed speed, so that the speed can be changed smoothly without giving vibration to the machine. Is possible.

  Further, in the above-described numerical control device, when the interrupt detection unit detects an interrupt instructing the stop of the machine tool, the coefficient creating unit determines that the moving speed is zero from the moving speed when the interrupt is detected. It is preferable to create the coefficient so that the speed gradually decreases until it becomes.

  According to this configuration, when an interruption instructing a stop is detected, the moving speed is gradually decreased and the stop is performed, so that the stop can be smoothly performed without giving vibration to the machine.

  In the above-described numerical control device, the coefficient creating means may have a predetermined instruction in which an interruption instructing the stop detected by the interrupt detecting means is predetermined and the amount of interpolation data stored in the storage means is predetermined. In the case of an interrupt indicating that the threshold value has been exceeded, the coefficient that gradually decreases from the moving speed at the time of detecting the interrupt until the moving speed becomes zero is created. Preferably, when the interpolation data read from the storage unit is less than a predetermined threshold, the execution data based on the interpolation data stored in the storage unit is output to the drive unit.

  According to this configuration, when a warning interruption that the amount of stored interpolation data is less than the threshold is detected, the stored interpolation data is used to gradually reduce the moving speed and stop. It becomes possible to stop smoothly without giving vibration to the machine.

  A machine tool control system according to another aspect of the present invention is a machine tool control system having an interpolation data generation device and one or more numerical control devices, wherein the interpolation data generation device analyzes a machining program, Interpolation data for driving a drive unit of a machine tool, the interpolation data generating unit generating interpolation data subjected to acceleration / deceleration processing, and data transmitting means for sequentially transmitting the interpolation data to the numerical controller The numerical controller includes a receiving unit that sequentially receives the interpolation data, a storage unit that temporarily stores the interpolation data received by the receiving unit, and the reception of the interpolation data by the receiving unit. Interpolation data output means for sequentially reading out the interpolation data from the storage unit in the execution order and outputting the execution data based on the read out interpolation data to the drive unit. The features.

  According to this configuration, since the interpolation data generating device creates the interpolation data that has been subjected to the acceleration / deceleration processing, the numerical control device can use a CPU that has lower performance than the conventional numerical control processing. That is, if one high-performance interpolation data creation device is prepared, interpolation data can be provided to a plurality of numerical control devices. Further, since the numerical control device can receive interpolation data from, for example, an in-house network, the numerical control device can be freely arranged.

  In the NC control method for a machine tool using the numerical control device and the machine tool control system according to the present invention, a device with lower performance can be used as the numerical control device provided for each machine tool.

It is a functional block diagram of the machine tool control system concerning an embodiment. It is a figure for demonstrating the override process of the numerical control apparatus shown in FIG. It is a figure for demonstrating the stop process of the numerical control apparatus shown in FIG. It is a figure for demonstrating the stop process when the interpolation data of the numerical controller shown in FIG. 1 run short. It is a figure for demonstrating the stop by the lack of interpolation data when a command path is a circular arc. It is a flowchart of the execution data output process of the numerical controller shown in FIG. It is a figure for demonstrating reading of the interpolation data. It is a figure which shows the example of the functional block of the conventional numerical control apparatus. It is a figure which shows the example of the conventional interpolation data.

<Embodiment>
Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the machine tool control system 100 according to the embodiment includes an interpolation data creation device 1 and a numerical control device 3 connected to the interpolation data creation device 1 via a network 2. In the embodiment, it is assumed that there is one interpolation data creation device 1 and the numerical control device 3 is installed for each of a plurality of machine tools.

  Here, an example of a conventional numerical control apparatus will be described with reference to FIG. A portion surrounded by a broken line is a function of a conventional numerical control device. One block is read from the NC program, the program analysis unit interprets the program, and the interpolation processing unit creates interpolation data. For example, when the command path of the machine tool instructed by the NC program is an arc, arc interpolation data is created based on the radius of the arc, the command speed, the current position of the tool with respect to the center of the arc, and the like. Interpolation data is a collection of XYZ coordinates (vector) indicating the trajectory of the tool. In order to reduce the shock generated in the machine due to a rapid change in the speed of each axis, the post-interpolation acceleration / deceleration processing unit performs processing for suppressing the shock in the interpolation data. Further, if necessary, the interpolation data is also subjected to processing for suppressing machining shape errors in the pre-interpolation acceleration / deceleration processing unit. When the numerical controller issues an instruction to the servo controller based on the interpolation data, it reads the next block of the NC program and repeats the process.

  Thus, in the conventional numerical control apparatus, the NC program is executed sequentially.

  In the machine tool control system 100 according to this embodiment, interpolation data obtained by performing the above-described post-interpolation acceleration / deceleration processing and pre-interpolation acceleration / deceleration processing (hereinafter referred to as “acceleration / deceleration processing”) in advance is created, and the machine tool Each of the numerical control devices reads and executes the interpolation data subjected to the acceleration / deceleration processing. In the machine tool control system 100, a large amount of processing is performed sequentially, that is, NC program interpretation processing and acceleration / deceleration processing are performed using a single interpolated data creation device with high processing capability, and acceleration / deceleration processing is performed. Create interpolation data. And the numerical control apparatus installed in each machine tool performs the interpolation data by which acceleration / deceleration processing was made beforehand. In other words, the numerical control device does not need to perform processing with a large amount of processing, and thus a CPU with relatively low performance can be used.

  Further, the numerical control device 3 of the machine tool control system 100 is devised for real-time control to cope with an override process (manual speed control) by an instruction from a user, an emergency stop process, and the like. In the conventional numerical control device, when dealing with such an instruction from the user, an emergency stop, or the like, for example, an interpolation process is performed so as to realize the user's instruction or the like in the post-interpolation acceleration / deceleration processing unit (see FIG. 8). Acceleration / deceleration processing is performed on the interpolation data created by the unit as the final processing. However, the numerical control device 3 according to the present embodiment that executes interpolation data that has been subjected to acceleration / deceleration processing in advance requires special measures.

  Hereinafter, a machine tool control system according to an embodiment will be described.

<Configuration>
FIG. 1 is a functional block diagram of the interpolation data creation device 1 and the numerical control device 3 of the machine tool control system 100.

  The interpolation data creation device 1 includes an NC program storage unit 11, a program analysis unit 12, an interpolation data creation unit 13, an interpolation data storage unit 14, and an interpolation data transmission unit 15.

  The NC program storage unit 11 stores an NC program for instructing a machining process to the machine tool.

  The program analysis unit 12 analyzes the NC program stored in the NC program storage unit 11 and converts it into execution format data.

  The interpolation data creation unit 13 includes an acceleration / deceleration processing unit 131 and an interpolation processing unit 132, creates interpolation data based on the execution format data created by the program analysis unit 12, and stores the created interpolation data as interpolation data. Store in the unit 14.

  The acceleration / deceleration processing unit 131 performs so-called pre-interpolation acceleration / deceleration processing and post-interpolation acceleration / deceleration processing as necessary. The acceleration / deceleration process is a process performed to suppress a rapid change in the speed of each axis of the machine tool. When the axis is moved from the first position to the second position, the speed at the first position is determined. To a process of gradually decelerating or accelerating the shaft feed speed so that the target speed is reached at the second position within a predetermined period (time constant). For example, as an acceleration / deceleration process before interpolation, in order to suppress a rapid change in the speed of each axis at the corner, the corner speed is calculated such that the speed change amount of each axis is less than the preset allowable speed difference. Is done. In the acceleration / deceleration processing before interpolation, the speed control is performed so that the feed speed is decelerated from the front of the corner so that the speed at the corner becomes the calculated corner speed, and the feed speed is accelerated after reaching the corner. Done. Further, in order to suppress a shock generated in the machine, as post-interpolation acceleration / deceleration processing, control is performed so that the speeds of the respective axes determined by the pre-interpolation acceleration / deceleration processing and the interpolation processing are averaged on a time basis.

  The interpolation processing unit 132 has a function of creating interpolation data from execution format data that has been subjected to pre-interpolation acceleration / deceleration processing by the acceleration / deceleration processing unit 131. In the embodiment, the acceleration / deceleration processing unit 131 and the interpolation processing unit 132 are described as separate functional units. However, the interpolation data may be created in cooperation with each other.

  Here, the interpolation data includes a plurality of coordinate values on the tool path of the machine tool, and the coordinate values indicate the coordinate values of the tool for each predetermined unit period. That is, the positions that should exist when the unit period elapses are shown in order. The interpolation data includes the movement distance (movement amount) of the unit period, in other words, the movement speed.

  The interpolation data storage unit 14 stores the interpolation data created by the interpolation data creation unit 13.

  The interpolation data transmission unit 15 reads out a predetermined amount of interpolation data from the interpolation data storage unit 14 in the execution order at a predetermined cycle, and transmits it to the numerical control device 3 via the network 2.

  Next, the numerical control device 3 includes an interpolation data receiving unit 31, an interpolation data writing unit 32, an interpolation data buffer 33 (storage unit), an interpolation data reading unit 34, an execution data output unit 35 (interpolation data output unit), A detection unit 36 and a coefficient generation unit 37.

  The interpolation data receiving unit 31 receives the interpolation data transmitted from the interpolation data creating apparatus 1 via the network 2. The network 2 may be either wired or wireless, as long as it can receive the interpolation data from the interpolation data creation device 1.

  In the embodiment, the interpolation data is managed by a so-called FIFO (First In First Out) method. Therefore, the interpolation data buffer 33 has a function of temporarily storing the interpolation data. The interpolation data writing unit 32 receives the interpolation data received by the interpolation data receiving unit 31 in the order received. Write to. Then, the interpolation data reading unit 34 reads from the interpolation data buffer 33 in the order written by the interpolation data writing unit 32, that is, in order from the oldest stored interpolation data. In the embodiment, the amount of interpolation data stored in the interpolation data buffer 33 is an amount that can instruct the servo motor controller 5 to drive for about 10 seconds. This data amount is determined in consideration of the CPU performance of the numerical control device 3, the performance of the servo motor control unit 5, and the like. Thus, in the machine tool system 100, it can be said that interpolation data is transmitted and executed in a streaming manner.

  The interpolation data reading unit 34 reads the interpolation data corresponding to the movement amount per unit time according to the coefficient representing the movement speed created by the coefficient creation unit 37 described later, and passes it to the execution data output unit 35. The amount of movement corresponding to the coefficient will be described in the section <Coefficient>.

  The execution data output unit 35 creates execution data from the interpolation data read from the interpolation data buffer 33 by the interpolation data reading unit 34, and outputs the created execution data to the servo motor control unit 5. The servo motor control unit 5 is a functional unit that controls a servo motor that drives a shaft or the like of a machine tool 6 installed in association with the numerical control device 3.

  The interrupt detection unit 36 detects external interrupts and internal interrupts. An external interrupt is a user instruction to the numerical control device 3. This instruction is performed, for example, when the operation unit 4 that is an operation panel or the like of the numerical control device 3 is operated by the user. For example, the moving speed of the machine tool is changed or stopped. Further, the interruption from the inside is an emergency stop instruction when a mechanical abnormality of the numerical control device 3 is detected, or when the interpolation data stored in the interpolation data buffer 33 is lost, or is determined in advance. This is a stop instruction or the like when the value is below the threshold. Note that interrupts other than these three types may be detected.

  The coefficient creation unit 37 includes an override processing unit 371, a stop processing unit 372, and a data shortage processing unit 373, and calculates a coefficient according to the type of interrupt detected by the interrupt detection unit 36. The coefficient may be a value for each predetermined period or a function. This coefficient is used when the interpolation data reading unit 34 reads the interpolation data.

  In the embodiment, the coefficient creation unit 37 detects three types of interrupts. Override interrupt, stop interrupt, data shortage interrupt. The override interrupt is an interrupt indicating that the user has operated the override switch of the operation unit 4 to give a speed change instruction. The stop interrupt is an interrupt indicating that a stop instruction has been made by the user via the operation unit 4 or that an abnormality has occurred in the numerical control device 3. The data shortage interrupt is an interrupt indicating that the amount of interpolation data stored in the interpolation data buffer 33 is below a threshold value. For example, the case where the interpolation data buffer 33 becomes empty may be caused by a communication abnormality in the network 2 or the like. This data shortage interruption is detected when the interpolation data reading unit 34 reads the interpolation data from the interpolation data buffer 33 and notifies the interrupt detection unit 36 of the interruption.

  The override processing unit 371 creates a coefficient when the interrupt detection unit 36 detects an override interrupt.

  The stop processing unit 372 creates a coefficient when the interrupt detection unit 36 detects a stop interrupt.

  The data shortage processing unit 373 creates a coefficient when the interrupt detection unit 36 detects a data shortage interrupt.

  The interpolation data creation device 1 and the numerical control device 3 can be configured using, for example, a computer, and software that programs NC program analysis and the like stored in a storage unit (not shown) such as a hard disk is stored in the CPU. The above-described program analysis unit 12 and the like are functionally configured in the computer. The numerical control device 3 may be a sequencer as long as it is a device provided with hardware resources capable of realizing each functional unit.

<Coefficient (Internal override value)>
Here, the coefficient which the coefficient preparation part 37 produces is demonstrated using FIGS.

  FIG. 2 is a time chart for explaining the coefficients created by the override processing unit 371 of the coefficient creating unit 37. In FIG. 2, four graphs are described, and the time indicated by the horizontal axis of all the graphs is the same.

  The top graph shows an example of the interpolation data stored in the interpolation data buffer 33. The horizontal axis indicates time, and the vertical axis indicates the number of pulses. The width of one rectangle indicates a unit period. The longer the vertical width of the rectangle, that is, the greater the number of pulses, the greater the power that the servo motor control unit 5 supplies to the motor. That is, the larger the number of pulses, the faster the moving speed of the tool (the larger the moving amount). In FIG. 2, the acceleration process and the deceleration process are performed using the same time constant. That is, the target speed is obtained when four unit periods have elapsed. Since the interpolation data shown here is interpolation data created by the interpolation data creation device 1, acceleration / deceleration processing is performed. Interpolated data that has not been subjected to acceleration / deceleration processing is shown in FIG.

  The second graph shows the setting value of the override switch set by the user. The horizontal axis represents time, and the vertical axis represents the set value. In FIG. 2, the initial set value is 100%, and the user sets the set value to 50% at the timing indicated by the arrow 10. 100% indicates the moving speed according to the interpolation data.

  The third graph shows the coefficients generated by the override processing unit 371 of the coefficient creating unit 37. The horizontal axis shows time, and the vertical axis shows coefficient values. The override processing unit 371 gradually increases from an initial override setting value, specifically, a value immediately before the user manually changes the override value (100%) to an override setting value (50%) set by the user. Is calculated (see arrow 11). The coefficient can be said to be an internal override value created by the numerical control device 3 in order to cope with interrupt processing. In the embodiment, as shown in parentheses, the coefficient of the setting value 100% is set to “1.0”, the coefficient of the setting value 50% is set to “0.5”, and the coefficient of the portion indicated by the arrow 11 is calculated. To do. In addition, the deceleration process indicated by the arrow 11 is performed using the time constant used in the interpolation data. Therefore, before the interruption occurs, that is, in normal time, the coefficient is “1.0”, and the coefficient indicated by the arrow 11 after the interruption occurs is “0.87” and “0.75” for each unit period. "," 0.63 "," 0.5 ", and so on.

  The fourth graph shows the execution data output by the execution data output unit 35 based on the interpolation data read by the interpolation data reading unit 34. The horizontal axis indicates time, and the vertical axis indicates the number of pulses. The interpolation data reading unit 34 reads the interpolation data corresponding to the coefficient from the interpolation data buffer 33. Specifically, the interpolation data reading unit 34 reads the interpolation data corresponding to the movement amount (number of pulses) corresponding to the coefficient.

Interpolation data per unit period read by the interpolation data reading unit 34, that is, the number of pulses P, where k indicates a coefficient and p indicates the number of pulses per 100% of the override setting value (interpolation data),
P = p × k (1)
It becomes.

  For example, when the coefficient is “0.5” and the number of pulses per 100% of the override setting value is “100” pulses, 0.5 × 100 = 50 pulses are read as the number of pulses in one unit period. 50 pulses remain in the interpolation data buffer 33. Therefore, when reading out three interpolation data of “100” pulses with the coefficient “0.5”, the data is read out in six unit periods.

  Here, for convenience of explanation, the interpolation data is “100” pulses and the coefficient is “0.5”. However, there are cases where the data cannot be actually divided. For example, when the coefficient is “0.543”, the integrated value of the coefficient corresponding to the number of readings is obtained, and the number of pulses per unit period is determined. An example of this is shown in FIG. The top graph shows an example of the interpolation data stored in the interpolation data buffer 33. The horizontal axis indicates time, and the vertical axis indicates the number of pulses. The width of one rectangle indicates a unit period. The second graph shows the execution data output by the execution data output unit 35 based on the interpolation data read by the interpolation data reading unit 34. The horizontal axis indicates time, and the vertical axis indicates the number of pulses. The numerical value in the rectangle indicates the number of times of reading. This example shows how the interpolation data reading unit 34 reads interpolation data for three unit periods when the speed is reduced to 54.3% by an override interrupt.

In the case of FIG. 7, the interpolation data reading unit 34 reads interpolation data for three unit periods in six times. Since the coefficient integration value for the first reading is “0.543”, the number of pulses per unit period is “54” pulses obtained by rounding off 54.3 obtained by the following equation.
100 × 0.543 = 54.3
Therefore, the interpolation data reading unit 34 reads the interpolation data for “54” pulses.

Since the coefficient integration value for the second time is “1.086”, the number of pulses per next unit period is “55” pulses obtained by rounding off 54.6 obtained by the following equation.
100+ (100 × 0.086) −54 = 54.6
“54” is the number of pulses read for the first time. Therefore, the interpolation data reading unit 34 reads the data for “46” pulses, which is the remainder of the first interpolation data, and the data for “9” pulses of the second interpolation data.

Since the coefficient integration value for the third time is “1.629”, the number of pulses per next unit period is “54” pulses obtained by rounding off 53.9 obtained by the following equation.
100+ (100 × 0.629) − (54 + 55) = 53.9
“54” is the number of pulses read for the first time, and “55” is the number of pulses read for the second time. The interpolation data reading unit 34 reads data for “54” pulses from the data for “91” pulses, which is the remainder of the second interpolation data.

Similarly, since the coefficient integration value for the fourth time is “2.172”, the number of pulses per next unit period is “54” pulses obtained by rounding off 54.2 obtained by the following equation.
100 + 100 + (100 × 0.172) − (54 + 55 + 54) = 54.2
Since the coefficient integration value for the fifth time is “2.715”, the number of pulses per next unit period is “55” pulses obtained by rounding off 54.5 obtained by the following equation.
100 + 100 + (100 × 0.715) − (54 + 55 + 54 + 54) = 54.5
The coefficient integration value for the sixth time is “3.258”, which exceeds the coefficient integration value 3.0 indicating the interpolation data for three, so the fourth interpolation data is set to “0” pulse, and the next The number of pulses per unit period is “28” pulses obtained by the following equation.
100 + 100 + 100 + (0 × 0.258) − (54 + 55 + 54 + 54 + 55) = 28
The coefficient integration value for the seventh time is “3.801”, and the number of pulses per unit period is “0” as in the following equation. The interpolation data reading unit 34 determines that there is no interpolation data when the number of pulses per unit period becomes “0”.
100 + 100 + 100 + (0 × 0.801) − (54 + 55 + 54 + 54 + 55 + 28) = 0
In this way, the interpolation data reading unit 34 integrates the coefficients to obtain the coefficient integrated value, calculates the number of pulses per next unit period, and reads the interpolation data for the calculated number of pulses, so that the total number of pulses Override processing can be performed without changing (movement amount). Specifically, it can be said that the coefficient integrated value indicates the integrated amount of the interpolation data, that is, how far the interpolation data should be read out. Therefore, the interpolation data reading unit 34 calculates the integration of interpolation data on the assumption that the integer part of the coefficient integration value indicates the number of interpolation data to be read and the decimal part indicates the ratio of data to be read from the next interpolation data. The amount of data to be read out is obtained by calculating the amount and subtracting the amount of data read so far from the calculated integrated amount.

In FIG. 7, since the number of pulses of all the interpolation data is described as “100”, “100” is used when calculating the integrated amount of the interpolation data from the coefficient integrated value. If the numbers are different, the number of each pulse is used. For example, it is assumed that the interpolation data of the first unit period is 100 pulses, the interpolation data of the second unit period is 90 pulses, and the third interpolation data is 80 pulses. In this case, when the coefficient integration value is “1.086” for the second time, the number of pulses per unit period is “54” pulses obtained by rounding off 53.74 obtained by the following equation.
100+ (90 × 0.086) −54 = 53.74
When the coefficient integrated value is “1.629” for the third time, the number of pulses per unit period is “49” pulses obtained by rounding off 48.61 obtained by the following equation.
100+ (90 × 0.629) − (54 + 54) = 48.61
When the coefficient integration value is “2.172” for the fourth time, the number of pulses per unit period is “47” pulses obtained by rounding off 46.76 obtained by the following equation.
100 + 90 + (80 × 0.172) − (54 + 54 + 49) = 46.76
As indicated by the arrow 13 in FIG. 2, even when the vehicle is stopped, the coefficients are accumulated as described above to calculate the number of pulses per unit period, so that the deceleration is performed as it is. In this case, the time constant will change.

  After the occurrence of the interrupt, the number of pulses per unit period is “87”, “75”, “63”, “50”, etc. according to a coefficient using a normal time constant as indicated by the arrow 12 in FIG. Since the target pulse number is gradually decreased, the machine operates smoothly.

  Note that FIG. 2 illustrates the case where an instruction to decrease the moving speed is given. However, a coefficient that gradually increases the speed is generated even when an instruction to increase the speed is given. The coefficient in this case is “1.0” when instructed, and increases, for example, “1.25” and “1.50”. Therefore, it is necessary to perform a process of automatically clamping (suppressing) the coefficient so as not to exceed the maximum speed permitted by the system.

  Next, FIG. 3 is a time chart for explaining the coefficients created by the stop processing unit 372 of the coefficient creating unit 37. In FIG. 3, four graphs are described. The top graph and the fourth graph are the same as the respective graphs in FIG. That is, the top graph shows an example of the interpolation data stored in the interpolation data buffer 33, and the fourth graph shows the execution data output by the execution data output unit 35.

  The second graph shows the stop signal. Suppose that the horizontal axis indicates time, the vertical axis indicates the value of the stop signal, and a stop instruction is generated when the signal value changes from “0” to “1”. FIG. 3 shows that a stop instruction has been generated at the timing indicated by the arrow 20.

  The third graph shows the coefficients generated by the stop processing unit 372 of the coefficient creating unit 37. The stop processing unit 372 gradually decelerates from the normal coefficient “1.0” (override set value 100%) to the coefficient “0.0” indicating the stop (override set value 0%). A coefficient is calculated (see arrow 21). The deceleration process indicated by the arrow 21 is performed using the time constant used in the interpolation data. When the time constant is 4, the coefficients are “0.75”, “0.50”, “0.25”, and “0.0”.

  In FIG. 3, since the stop signal is “1” when the coefficient is “1.0” (override set value 100%) at the normal time, the coefficients are “0.75”, “ 0.50 "and" 0.25 ". If the stop signal is" 1 "when the override setting value is 50%, the coefficients are" 0.38 "and" 0.25 ". , “0.13” or the like.

  The fourth graph shows the execution data output by the execution data output unit 35 based on the interpolation data read by the interpolation data reading unit 34. As described above, the interpolation data reading unit 34 reads the interpolation data corresponding to the coefficient created by the stop processing unit 372. Interpolation data read out by the interpolation data reading unit 34 according to the coefficient per unit period has a pulse number of “75”, “50”, “25”, “0” as indicated by the arrow 22. "... will gradually decrease, and the machine will stop smoothly. After stopping, when it is confirmed that the stop factor has been released, the stop signal is set to “0” and the coefficient is returned to “1.0”.

  Next, FIG. 4 is a time chart for explaining the coefficients created by the data shortage processing unit 373 of the coefficient creating unit 37. FIG. 4 shows four graphs. The top graph and the fourth graph are the same as the graphs of FIGS. That is, the top graph shows an example of the interpolation data stored in the interpolation data buffer 33, and the fourth graph shows the execution data output by the execution data output unit 35.

  The first graph shows the interpolation data stored in the interpolation data buffer 33, and the interpolation data indicated by the white rectangle is stored. When the interpolation data reading unit 34 reads the interpolation data from the interpolation data buffer 33 and the remaining interpolation data is less than the predetermined number (threshold), the interpolation data reading unit 34 generates a buffer empty alarm signal (in the interrupt detection unit 36). Notice). In the embodiment, the threshold value is “2”. That is, when the number of remaining interpolation data is one (see arrow 30), a buffer empty alarm signal is generated. A hatched rectangle indicated by the arrow 31 indicates a copy (duplication) of the last interpolation data (see the arrow 30) stored in the interpolation data buffer 33.

  The second graph shows a buffer empty alarm signal. It is assumed that an alarm is generated when the horizontal axis indicates time, the vertical axis indicates the value of the alarm signal, and the signal value changes from “0” to “1”. FIG. 4 shows that a buffer empty alarm signal is generated at the timing indicated by the arrow 33.

  The third graph shows the coefficients generated by the data shortage processing unit 373 of the coefficient creating unit 37. The data shortage processing unit 373 gradually decelerates from the normal coefficient “1.0” (override set value 100%) to the coefficient “0.0” indicating the stop (override set value 0%). A simple coefficient is calculated (see arrow 34). The deceleration process indicated by the arrow 34 is performed using the time constant used in the interpolation data. When the time constant is 4, the coefficients are “0.75”, “0.50”, “0.25”, and “0.0”.

  In FIG. 4, since the stop signal is “1” when the coefficient is “1.0” (override set value 100%) at the normal time, the coefficients are “0.75”, “ 0.50 "and" 0.25 ".

  The fourth graph shows the execution data output by the execution data output unit 35 based on the interpolation data read by the interpolation data reading unit 34. As described above, the interpolation data reading unit 34 reads the interpolation data corresponding to the coefficient created by the data shortage processing unit 373. The interpolated data moving speed read by the interpolating data reading unit 34 in accordance with the coefficient for each unit period has the number of pulses of “75”, “50”, “25”, “0” as indicated by the arrow 32. "... will gradually decrease, and the machine will stop smoothly. The hatched rectangle is execution data using the copied interpolation data (see arrow 31) shown in the first graph. The portion where the second execution data from the right is not hatched is the remaining interpolation data when the interpolation data reading unit 34 reads out the interpolation data (“75”) for the third execution data from the right. (“25”). After stopping, when it is confirmed that the stop factor has been released, the stop signal is set to “0” and the coefficient is returned to “1.0”.

  When a data shortage interrupt occurs, it indicates that the interpolation data stored in the interpolation data buffer 33 is almost gone. Therefore, the last interpolation data stored in the interpolation data buffer 33 is copied to supplement the interpolation data, and the machine is smoothly stopped. That is, a copy of the interpolation data stored in the interpolation data buffer 33 is stored in the interpolation data buffer 33, the interpolation data corresponding to the movement amount according to the coefficient is read from the interpolation data buffer 33, and based on the read interpolation data. The execution data is output to the servo motor control unit 5.

  However, when interpolation data copied in this way is used, the interpolation data is different from the interpolation data created from the NC program, so the combined path (path) of the XYZ axes may follow a path different from the original command path. . An example in the case of different routes is shown in FIG. FIG. 5 shows a case where the command path is an arc. Consider a case where the command path is a circular path from the start point 40 to the end point 41 (see the broken line 50). Assume that a buffer empty alarm has occurred when the tool has moved to position 42 via path 51. At that time, it is assumed that the interpolation data buffer 33 stores the interpolation data up to the position 43. At the time of the position 42 where the interruption occurs, the coefficient is calculated as described above, and the vehicle moves to the position 43 via the path 52 while gradually decelerating. After that, since the interpolation data is copied and used, the linear movement starts from the position 43 and stops at the position 44 via the path 53 deviated from the original path 50. Although a route different from the command route is moved, it is important to stop the tool promptly and smoothly because an abnormal situation occurs when a buffer empty alarm occurs. Here, the last interpolation data stored in the interpolation data buffer 33 is repeatedly used. However, the stored interpolation data may be used. For example, the interpolation data is estimated by estimating a locus from a plurality of interpolation data. You may create it.

  In the above acceleration / deceleration processing, it is assumed that an override value common to all axes is used instead of calculation in units of axes. Therefore, there is no calculation error in the combined path of the XYZ axes. However, as described above, the path may be different in the portion using the interpolation data supplemented on the numerical controller side.

<Operation>
Next, a process of outputting execution data of the numerical control device 3 of the machine tool control system 100 will be described with reference to FIG. FIG. 6 is a flowchart of the execution data output process of the numerical controller 3.

  It is assumed that the interpolation data creating apparatus 1 creates interpolation data subjected to acceleration / deceleration processing from an NC program stored in the NC program storage unit 11 in advance and stores it in the interpolation data storage unit 14. Note that the creation of interpolation data from the NC program and the transmission to the numerical controller 3 may be performed in parallel.

  The user inputs an instruction to start transmission of interpolation data to the interpolation data creation device 1 via a user interface unit (not shown) of the interpolation data creation device 1. The interpolation data creating apparatus 1 that has detected that a transmission start instruction has been input requests the interpolation data transmission unit 15 to transmit interpolation data. The requested interpolation data transmission unit 15 reads out a predetermined amount of interpolation data from the interpolation data storage unit 14 in the execution order in a predetermined cycle, and starts transmission to the numerical control device 3 via the network 2. .

  When the interpolation data receiving unit 31 of the numerical control device 3 receives the interpolation data transmitted from the interpolation data creating device 1, it passes the received interpolation data to the interpolation data writing unit 32 to request storage. Upon receiving the request, the interpolation data writing unit 32 stores the received interpolation data in the interpolation data buffer 33. The interpolation data receiving unit 31 and the interpolation data writing unit 32 repeat the process of receiving the interpolation data and storing it in the interpolation data buffer 33.

  When the interpolation data is written in the interpolation data buffer 33, the numerical controller 3 sets an initial value “1.0” indicating that the coefficient operates at the moving speed according to the interpolation data as a coefficient (step S10). The reading unit 34, the execution data output unit 35, the interrupt detection unit 36, and the coefficient creation unit 37 are instructed to start processing.

  When the interrupt detection unit 36 has not detected an interrupt (step S11: No, step S12: No, step S13: No), the coefficient creation unit 37 sets “1.0” that is initially set as a coefficient. The data is output to the interpolation data reading unit 34. As described above, the interpolation data reading unit 34 reads the interpolation data of the movement amount according to the coefficient passed from the coefficient creating unit 37 from the interpolation data buffer 33 and outputs it to the execution data output unit 35 (step S14).

  The execution data output unit 35 to which the interpolation data is passed from the interpolation data reading unit 34 creates execution data of the movement speed based on the interpolation data and outputs it to the servo motor control unit 5 (step S15). Then, the numerical controller 3 repeats the process from step S11. In addition, when detecting an interrupt, the interrupt detection unit 36 generates a signal corresponding to the detected interrupt. Specifically, when a data shortage interrupt is detected, the buffer empty alarm signal is set to “1” (see FIG. 4), and when a stop interrupt is detected, the stop signal is set to “1” (see FIG. 3). .

  In step S11, when the interrupt detection unit 37 detects a data shortage interrupt (when the buffer empty alarm signal is “1”) (step S11: Yes), it notifies the coefficient creation unit 37 and requests the creation of the coefficient. To do.

  Upon receiving the request, the coefficient creation unit 37 instructs the data shortage processing unit 373 to calculate the coefficient. Upon receiving the instruction, the data shortage processing unit 373 calculates a coefficient as described in the section <Coefficient> (step S16). The coefficient creating unit 37 outputs the calculated coefficient to the interpolation data reading unit 34.

  The interpolation data reading unit 34 copies the interpolation data stored last (step S17), and reads the interpolation data corresponding to the coefficient received from the coefficient creating unit 37 as described in the section <Coefficient> It outputs to the execution data output part 35 (step S14). The execution data output unit 35 to which the interpolation data is passed from the interpolation data reading unit 34 creates execution data of the moving speed based on the interpolation data, and outputs the created execution data to the servo motor control unit 5 (step S15). .

  In step S12, when the interrupt detection unit 37 detects a stop interrupt (when the stop signal is “1”) (step S12: Yes), it notifies the coefficient creation unit 37 and requests the creation of a coefficient.

  The coefficient creation unit 37 that has received the request instructs the stop processing unit 372 to calculate the coefficient. Upon receiving the instruction, the stop processing unit 372 calculates a coefficient as described in the section <Coefficient> (step S18). The coefficient creating unit 37 outputs the calculated coefficient to the interpolation data reading unit 34.

  As described in the section <Coefficient>, the interpolation data reading unit 34 reads the interpolation data corresponding to the coefficient received from the coefficient creating unit 37 and outputs it to the execution data output unit 35 (step S14). The execution data output unit 35 to which the interpolation data is passed from the interpolation data reading unit 34 creates execution data of the moving speed based on the interpolation data, and outputs the created execution data to the servo motor control unit 5 (step S15). .

  In step S13, when the interrupt detection unit 36 detects an override interrupt (step S13: Yes), the coefficient generation unit 37 is notified to request the generation of a coefficient.

  Upon receipt of the request, the coefficient creating unit 37 instructs the override processing unit 371 to calculate the coefficient. Upon receiving the instruction, the override processing unit 371 calculates a coefficient as described in the section <Coefficient> (step S19). The coefficient creating unit 37 outputs the calculated coefficient to the interpolation data reading unit 34.

  As described in the section <Coefficient>, the interpolation data reading unit 34 reads the interpolation data corresponding to the coefficient received from the coefficient creating unit 37 and outputs it to the execution data output unit 35 (step S14). The execution data output unit 35 to which the interpolation data is passed from the interpolation data reading unit 34 creates execution data of the moving speed based on the interpolation data, and outputs the created execution data to the servo motor control unit 5 (step S15). .

  As described above, the numerical control device 3 can easily cope with the change of the override switch, the emergency stop process, or the failure to reach the interpolation data due to a communication failure or the like.

  In the embodiment, the interpolation data reading unit 34 reads the amount of interpolation data corresponding to the coefficient from the interpolation data buffer 33. This is not only to read the amount of interpolation data corresponding to the coefficient directly from the interpolation data buffer 33, but, for example, the interpolation data for one record is sequentially read from the interpolation data buffer 33 into the working memory, and one record is converted into the coefficient in the working memory. The interpolation data may be subdivided and read out as a result. As a result, it is only necessary to read out the amount of interpolation data corresponding to the coefficient from the interpolation data buffer 33. In the embodiment, when the interrupt detection unit 37 detects a data shortage interrupt, the interpolation data reading unit 34 copies the last interpolation data stored in the interpolation data buffer 33 to the interpolation data buffer 33. However, for example, the interpolation data read last may be repeatedly used on the assumption that the interpolation data is read next. This working memory may be a memory in the interpolation data buffer 33, a memory dedicated to the interpolation data reading unit 34, or a memory in the numerical controller 3.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

DESCRIPTION OF SYMBOLS 1 Interpolation data creation apparatus 2 Network 3 Numerical control apparatus 5 Servo motor control part 6 Machine tool 11 NC program memory | storage part 12 Program analysis part 13 Interpolation data creation part 15 Interpolation data transmission part 31 Interpolation data reception part 33 Interpolation data buffer (storage part) )
34 Interpolation data reading unit (interpolation data output means)
35 Execution data output unit (interpolation data output means)
36 Interrupt detection unit 37 Coefficient creation unit 371 Override processing unit 372 Stop processing unit 373 Data shortage processing unit

Claims (8)

Interpolation data for driving the machine tool drive unit based on the machining program, receiving means for sequentially receiving in order of execution;
A storage unit temporarily storing a predetermined amount of interpolation data received by the receiving unit;
In parallel with the reception of the interpolation data by the receiving means, the interpolation data output means for sequentially reading the interpolation data from the storage unit in the execution order, and outputs the execution data based on the read interpolation data to the drive unit,
The numerical control device, wherein the interpolation data is interpolation data on which acceleration / deceleration processing has been performed in advance. The interpolation data includes data indicating the moving speed of the machine tool,
Interrupt detection means for detecting an interrupt;
In accordance with an instruction indicated by the interrupt detected by the interrupt detection means, a coefficient creating means for creating a coefficient representing a time-series change in the moving speed is further provided,
The interpolation data output unit reads interpolation data corresponding to a movement amount corresponding to the coefficient from the storage unit, and outputs the execution data based on the read interpolation data to the drive unit. The numerical control apparatus according to 1. When the interrupt detection unit detects an interrupt instructing the change of the moving speed, the coefficient creating unit gradually increases the speed from the moving speed at the time of detecting the interrupt to the instructed moving speed. The numerical control device according to claim 2, wherein the coefficient that changes is created. When the interrupt detection means detects an interrupt that instructs the machine tool to stop, the coefficient creating means gradually decreases from the moving speed at the time of detecting the interrupt until the moving speed becomes zero. The numerical control device according to claim 2, wherein the coefficient is generated. The coefficient creating means is an interrupt indicating that the interruption instructing the stop detected by the interrupt detecting means is less than a predetermined threshold value which is stored in the storage means. If there is, create the coefficient that gradually decreases from the moving speed when the interrupt is detected until the moving speed becomes zero,
The interpolation data output means outputs the execution data based on the interpolation data stored in the storage unit to the drive unit when the interpolation data read from the storage unit is less than a predetermined threshold value. The numerical control apparatus according to claim 2, wherein the numerical control apparatus is characterized. A machine tool control system having an interpolation data generation device and one or more numerical control devices,
The interpolation data generation device includes:
Interpolation data for analyzing the machining program and driving the drive unit of the machine tool, and generating interpolation data subjected to acceleration / deceleration processing; and
The numerical control device comprises data transmission means for sequentially transmitting the interpolation data,
The numerical controller is
Receiving means for sequentially receiving the interpolation data;
A storage unit for temporarily storing the interpolation data received by the receiving unit;
In parallel with the reception of the interpolation data by the receiving means, interpolation data output means for sequentially reading the interpolation data from the storage unit in the execution order and outputting the execution data based on the read interpolation data to the drive unit. Machine tool control system characterized by A numerical control method used in a numerical control device including a storage unit temporarily storing a predetermined amount of interpolation data for driving a drive unit of a machine tool based on a machining program,
Receiving step for sequentially receiving the interpolation data in the order of execution;
In parallel with the reception of the interpolation data in the reception step, the interpolation data output step of sequentially reading the interpolation data from the storage unit in the execution order, and outputting the execution data based on the read interpolation data to the drive unit,
The numerical control method, wherein the interpolation data is interpolation data for which acceleration / deceleration processing has been performed in advance. A numerical control program used in a numerical control device including a storage unit temporarily storing a predetermined amount of interpolation data for driving a drive unit of a machine tool based on a machining program,
Receiving means for sequentially receiving the interpolation data in the order of execution;
In parallel with the reception of the interpolation data by the receiving means, the interpolation data output means for sequentially reading the interpolation data from the storage section in the execution order and outputting the execution data based on the read interpolation data to the drive section. Make it work
The numerical control program, wherein the interpolation data is interpolation data for which acceleration / deceleration processing has been performed in advance.

Images