JP2008130013A - Numerical control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch cutting feed mode/fast-forward mode in a path table operation. <P>SOLUTION: A command R200 for switching to a fast-forward mode in accordance with a reference value L and a command R201 for switching to a cutting feed mode are set and stored in a path table in which the position of a control shaft is stored in accordance with the reference value L, the reference value L and a shaft position of the i-th row command from the path table are defined as start points (Rs(L) and Rs(X)) (S3, S14 and S15), and the reference value L and the shaft position of the (i+1)-th row command are defined as end points (Re(L) and Re(X)) (S5). Movement is performed between the start points and the end points by a command function, while synchronizing with a reference value Lm (S11 to S13). When the commands R200 and R201 are read out, they are switched to servo control gains or the like suitable for a commanded feeding mode (S6, S7, S8 and S9). Cutting feed and fast-forward feed are possible during path table operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a numerical control device that controls machine tools and various industrial machines, and more particularly to a numerical control device that controls the position of a control axis with respect to a reference value such as time and spindle position based on table format data.

  The position of the control axis with respect to the reference value such as time and spindle position is stored in the memory as table format data as a path table. Based on the data stored in this path table, the reference axis is synchronized with the reference value. A path table operation for reading the position of the control axis corresponding to the value from the path table and controlling the position of the control axis at the position is already known (see Patent Document 1).

  In machining with a machine tool in this pass table operation, it is possible to move the tool freely without being constrained by the conventional machining program, and the machining time is shortened and the machining accuracy is improved.

Japanese Patent No. 3671020

  In conventional pass table operation, the purpose is to shorten the machining time and increase the accuracy of machining, so there are many cases where the part to be cut is made into a pass table and the pass table is operated. Only. In the path table operation, the gain of the motor controller that feeds back the position and speed of the servo motor that drives the control axis, and the feed forward coefficient when performing feed forward control are fixed to the gain for cutting feed and the feed forward coefficient. Has been. For this reason, when a high-speed movement equivalent to fast-forwarding is performed in the path table operation, there is a problem that the torque becomes excessively high, and a motor control suitable for high-speed movement cannot be performed.

  Accordingly, an object of the present invention is to provide a numerical control device capable of path table operation that enables motor control suitable for high-speed movement.

  The present invention stores a path table in which a reference value and a control axis position are associated with each other on the basis of time or spindle position, and sequentially reads the reference value of the path table and the control axis position. In the numerical control apparatus that controls the position of the control axis in synchronization with the reference value, a switching command for cutting feed and rapid feed mode is set in the path table, and the switching command is read from the path table. Means for switching the control gain of the servo motor control means for driving and controlling the control shaft to the value of the feed mode instructed to switch when the reference value reaches the reference value stored in the switching command. It is characterized by that. When the servo motor control means includes feed forward control, the coefficient of the feed forward control is also switched to the value of the feed mode instructed to be switched.

  In the pass table operation, it is possible to switch between cutting feed and fast feed, and a high speed movement pass table operation can be performed.

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 10 according to an embodiment of the present invention. The CPU 11 is a processor that controls the numerical controller 10 as a whole. The CPU 11 reads out a system program stored in the ROM 12 via the bus 19 and controls the entire numerical control device according to the system program. The RAM 13 stores temporary calculation data, display data, and various data input by the operator via a display / MDI unit 20 including a display composed of a CRT, liquid crystal, etc., and manual input means composed of a keyboard. Is stored. The SRAM 14 stores a machining program read through the interface 15 and a machining program input through the display / MDI unit 20. The display / MDI unit 20 is connected to the bus 19 via the interface 18.

The interface 15 enables connection between the numerical controller 10 and an external device such as the memory card 21. A PMC (programmable machine controller) 16 is a sequence program built in the numerical control device 10 and outputs a signal to an auxiliary device of a machine tool to be controlled via the I / O unit 17 for control. In addition, it receives signals from various switches on the operation panel provided on the machine tool main body, which is a control object controlled by the numerical control device, performs necessary signal processing, and then passes them to the CPU 11.
Axis control circuits 31x, 31y, and 31z that drive and control servo motors 30x, 30y, and 30z for the X, Y, and X axes receive movement command amounts for the respective axes from the CPU 11, and send the commands for the respective axes to servo amplifiers 32x and 32y. , 32z. In response to this command, the servo amplifiers 32x, 32y, and 32z drive the servo motors 30x, 30y, and 30z of each axis of the machine (control target). Each axis servo motor 30x, 30y, 30z has a built-in position / velocity detector, and the position / velocity feedback signal from this position / velocity detector is fed back to the axis control circuits 31x, 31y, 31z, Perform feedback control. In FIG. 1, the position / speed feedback is omitted.

  The spindle control circuit 40 receives a spindle rotation command and outputs a spindle speed signal to the spindle amplifier 41. The spindle amplifier 41 receives the spindle speed signal and rotates the spindle motor 42 at the commanded rotational speed. The position coder 43 feeds back a feedback pulse to the spindle control circuit 40 in synchronization with the rotation of the spindle motor 42 to perform speed control.

  As described above, the hardware configuration of the numerical control apparatus 10 is the same as that of the conventional numerical control apparatus. However, in this embodiment, the position of the control axis with respect to the reference value is set in the SRAM 14 in order to synchronize with the reference value. Is stored in advance in a table format data, and a cutting feed and fast feed mode switching command is incorporated into the pass table, and the cutting feed motor control and fast feed high-speed movement during the path table operation. It differs from the prior art in that it is configured to allow motor control. As the reference value, time or the position of the spindle is used. When using time, a reference value is generated based on the clock in the numerical controller 10, and when using the spindle position, the spindle position signal from the position coder 43 is used. Is read via the spindle control circuit 40, and the read spindle position is used as a reference value.

An example of a path table in which this mode switching command is incorporated is shown below.
L0 X0.0 R1
L900 X10.0 R1
L1000 R200
L1100 X100.0 R1
L2100 X550.0 R1
L2200 R201
L2300 X550.0 R1
L4300 X50.0 R1
...
...
In the path table data described above, “L □” indicates a reference value corresponding to the reference value, “X □” indicates the position of the control axis by the path table operation, and in this example, the control axis is the X-axis path. An example of table operation is shown. Note that the reference value commanded in the path table is described as L, and the reference value read for synchronization is described as Lm. Also, the command of R1 is a command for performing contour control with a linear function, and movement command distribution processing is performed so as to perform contour control of connection between the positions of each control axis commanded by the path table by a straight line of the linear function. It is a command to be performed. Further, by commanding these commands as R2 and R3, it is also possible to command a quadratic function connection and a cubic function connection. Since this point is described in Patent Document 1 described above and is not directly related to the present invention, details thereof are omitted.
The R200 command is a feed mode switching command for switching from cutting feed to rapid feed, and the R201 command is a feed mode switching command for switching from fast feed to cutting feed.

FIG. 2 is a graph showing the operation by this path table, that is, the relationship of the position of the X axis of the control axis with respect to the reference value.
The path table operation is started from the position X = 0 of the X axis of the control axis with the reference value L = 0 as described in one line of the path table.
The next line is L = 900, X = 10.0, and is a command for connecting a linear function of R1, and as shown in FIG. 2, when the reference value Lm becomes the command value L = 900, X = The X-axis servomotor 30x is controlled by linear function connection (straight line connection) so as to be 100.0. In the next line, since the command R200 for switching to the rapid feed at the reference value L = 1000 is commanded, when the reference value Lm becomes “1000”, the mode is switched to the fast feed mode to drive each control axis. When the control gain (feedback control gain of position and speed) and also the feedforward control are performed in the axis control circuits 31x, 31y, 31z of the control means of the servo motors 30x, 30y, 30z, the feedforward coefficient is Change to the fast-forward value set in the parameter memory.

  In the next line, “L1100 X100.0 R1” is commanded, so the X axis does not move until the reference value Lm = 1100, and in the next line, “L2100 X550.0 R1” is commanded. Therefore, when the reference value Lm is between “1100” and “2100”, the X-axis is moved from “100.0” to “550.0” in a linear function connection (straight line connection) by rapid traverse. The servo motor 30x is driven and controlled.

  In the next line, since "L2200 R201" is commanded, when the reference value Lm reaches "2200", the cutting feed mode is switched (switching of control gain and feedforward coefficient values). Is “L2300 X550.0 R1” and the next command is “L4300 X50.0 R1”. Wait until the reference value Lm becomes “2300”, and when the reference value Lm becomes “2300”, Before the value Lm reaches “4300”, the X-axis servomotor 30x is driven by a linear function connection (straight line connection) by cutting feed from the position of “550.0” to “50.0”. Be controlled.

  As described above, in the example of the path table described above, as shown in FIG. 2, the X axis of the control axis is driven and controlled, and during the path table operation, from cutting feed to rapid feed or vice versa. The control axis can be controlled by switching from rapid feed to cutting feed.

  FIG. 3 is a flowchart showing an algorithm of processing when the CPU 11 of the numerical control device performs a path table operation. Also in this flowchart, the control axis controlled by the path table operation is described as the X axis, but it goes without saying that other axes may be controlled.

  When starting the pass table operation, the control axis is positioned at the pass table operation start position. When a pass table operation command is input, the CPU 11 first executes the line in which the command in the pass table is described. Is set to "1" (step S1), i-row data in the path table is read (step S2), and the command reference value Li is stored in the register Ms (L) for storing the path start point. If the command for the control axis, that is, the command position for the X axis is designated, the position Xi is stored in the register Ms (X) for storing the starting point of the path (step S3). Next, the data in the (i + 1) line of the path table is read (step S4), the command reference value Li + 1 is stored in the register Me (L) for storing the path end point, and the command to the X axis of the control axis is stored. If the position is designated, the position Xi + 1 is stored in the register Me (X) that stores the end point of the path (step S5).

  Whether there is a “R200” feed mode switching command (step S6), a “R201” command (step S8), or a table operation end command (i + 1) row data read in step S4 (step S6) In step S10), if there is no such command, the reference value Lm is read (step S11), and it is determined whether the reference value Lm is equal to or greater than the value (Li + 1) stored in the register Me (L) in step S5. (Step S12). It is assumed that the path table data is registered and the table operation is performed on the assumption that the reference value Lm increases.

  At first, since the reference value Lm has not reached the end point value (Li + 1) stored in the register Me (L), the process proceeds to step S13, where the start point stored in the registers Ms (L) and Ms (X) is stored. Based on the reference value Li, the X-axis position Xi, the end-point reference value Li + 1 stored in the registers Me (L) and Me (X), and the X-axis position Xi + 1, the data is read in step S4. , Processing by contour control function command R (R1, R2, R3, etc.) is performed, the position of the X axis in the interpolation cycle is obtained, and the movement amount of the difference from the position of the X axis in the previous cycle is driven. Output to the axis control circuit 31x. Thereafter, the processing of steps S11 to S13 is repeatedly executed for each interpolation cycle, the movement amount by the commanded function is obtained and output to the X-axis axis control circuit 31x, and the X-axis axis control circuit 31x performs this commanded movement. Based on the position and speed fed back from the quantity and position / velocity detector, position and speed feedback control, and motor control such as feedforward control are performed, and the X-axis servomotor 30x is driven via the servo amplifier 32x. Control.

  If the reference value Lm becomes equal to or greater than the end point value (Li + 1) stored in the register Me (L) during repeated execution of steps S11 to 13, the pointer i is incremented by 1 (step S14), and the end point reference value is reached. Is stored in the register Ms (L) that stores the reference value of the start point, the value of the register Me (X) that stores the end point X-axis position, and the end point X-axis position. The data is stored in the register Ms (X) to be stored (step S15), the process returns to step S4, and the processes of steps S4 to S6, S8, and S10 to S15 described above are executed.

  When the processing of steps S4 to S6, S8, and S10 to S15 is being executed, if it is detected in step S6 that the feed mode command R200 for switching from cutting feed to fast feed is read, the set fast feed is set. Are switched to parameter values such as motor control gains of the axis control circuits 31x, 31y, 31z for controlling the servo motors of the control axes. That is, the position of the servo motor, the position for controlling the speed, the position loop gain for speed feedback control, the speed control gain, and the like are changed to the values for fast-forwarding. If the axis control circuits 31x, 31y, and 31z also perform feedforward control, the feedforward coefficient of this feedforward control is also switched to the fast forward value (step S7), and the process proceeds to step S11. Thereafter, the servo motors 30x, 30y, and 30z are controlled by the axis control circuits 31x, 31y, and 31z based on the switched fast-feed motor control gains and coefficients.

  On the other hand, when it is detected in step S8 that the command R201 for switching from rapid feed to cutting feed is read, the parameters for cutting feed are read and the motor control gains and feeds of the axis control circuits 31x, 31y, 31z are read. The forward coefficient is switched to a value for cutting feed (step S9), and the process proceeds to step S11. Thereafter, the servo motor is controlled on the basis of the gain and coefficient of the motor control for the cutting feed that has been switched by the axis control circuit.

  When the processes from step S4 to step S15 described above are repeatedly executed and it is determined in step S10 that the table operation end command has been read, the table operation ends.

  Therefore, in the example of the above-described path table data for executing the operation shown in FIG. 2, the pointer i is set to “1” in step S1, and the reference i commanded in the line i = 1 in step S3. The value L = 0 is stored in the register Ms (L), and the X-axis position X = 0.0 is stored in the register Ms (X). In step S5, “900” is stored in the register Me (L), and “100.0” is stored in the register Me (X). Then, by the processing in steps S11 to S13, as shown in FIG. 2, the start point (Ms (L), Ms (X)) = (L1, X1) = (0, 0.0) to the end point (Me (L) , Me (X)) = (L2, X2) = (900, 100.0), the linear movement contour control is performed by the linear function (R1).

  Then, when the reference value Lm becomes “900”, the process proceeds from step S12 to step S14, the pointer i is incremented (i = 2), and the process of step S15 of the replacement process starting from the previous end point is performed. (Ms (L), Ms (X)) = (L2, X2) = (900, 100.0) and the next three lines (i + 1 = 2 + 1 = 3) are read in step S4. Since the command for the line is “L1000 R200”, in step S5, “1000” is stored in Me (L), but since there is no command in Me (X), the “ “100.0” is stored. That is, the end point (Me (L), Me (X)) = (L3, X3) = (1000, 100.0). Further, since it is a command of “R200”, the mode is switched to the fast-forward mode (step S7), and the processing of steps S11 to S13 is performed, but the start point (Ms (L), Ms (X)) = (L2, X2 ) = (900, 100.0) and the end point (Me (L), Me (X)) = (L3, X3) = (1000, 100.0), the X axis does not move.

  When the reference value Lm reaches the end point position 1000, the pointer i is set to “3” (step S14), “1000” is stored in the register Ms (L) storing the start point, and “100.0” is stored in Ms (X). Is stored (step S15). In step S4, the command of i + 1 = 4th line is read. In step S5, "1100" is stored in the end point register Me (L), and "100.0 is stored in Me (X). "Is stored. Then, although the processes of steps S11 to S13 are performed, the X-axis servo motor 30x does not move and remains stopped because the X-axis position of the start point and the end point are the same.

  When the reference value Lm becomes “1100”, the pointer i is “4”, “1100” is stored in the register Ms (L), and “100.0” is stored in Ms (X) (steps S14 and S15). In step S5, “2100” is stored in the register Me (L) and “550.0” is stored in Ms (X) in accordance with the instruction on the fifth line. Therefore, in the processing of steps S11 to S13, the start point ( From Ms (L), Ms (X)) = (1100, 100.0) to the end point (Me (L), Me (X)) = (2100, 550.0), rapid feed by linear feed of the linear function is illustrated. As shown in FIG.

  Then, when the reference value Lm reaches “2100”, i = 5, Ms (L) = 2100, Ms (X) = 550.0, and in step S5, the command of six lines of i + 1 line is Me (L ) = 2200, the value of Me (X) is “550.0” without change, and “R201” is commanded. Therefore, the cutting feed mode is switched in step S9. In the processing in steps S11 to S13, Since the start point and end point of the X axis are the same “550.0”, there is no movement.

  When the reference value Lm reaches “2200”, i = 6, Ms (L) = 2200, Ms (X) = 550.0 (steps S14 and S15), and by the command in the i + 1 = 6 + 1 = 7th line, Me (L) = 2300, Me (X) = 550.0, and in the processing in steps S11 to S13, since the start point and the end point of the X axis are the same “550.0”, there is no movement.

When the reference value Lm reaches “2300”, i = 7, Ms (L) = 2300, Ms (X) = 550.0 (steps S14 and S15), and by the command in the i + 1 = 7 + 1 = 8th line, Me (L) = 4300 and Me (X) = 50.0, and in the processing in steps S11 to S13, the start point (Ms (L), Ms (X)) = (2300, 550.0) to the end point (Me ( The linear cutting feed of the linear function is executed until L), Me (X)) = (4300, 50.0).
Hereinafter, the above-described operation is executed until the table operation end command is read.

It is a principal part block diagram of the numerical control apparatus of one Embodiment of this invention. It is an example of the pass table driving | operation in the embodiment. It is a flowchart which shows the algorithm of the path table driving | operation in the embodiment.

Explanation of symbols

  10 Numerical controller

Claims (2)

A path table in which the reference value and the control axis position are associated with each other is stored in a memory with the time or the spindle position as a reference, the reference value of the path table and the control axis position are sequentially read out, and the reference value In the numerical control device that controls the position of the control axis in synchronization with
In the path table, a switching command for cutting feed and rapid feed mode is set,
The switching command is read from the path table, and when the reference value reaches the reference value in which the switching command is stored, the control gain of the control means of the servo motor that drives and controls the control shaft is commanded to switch. A numerical control device comprising means for switching to a value in a feed mode.   2. The numerical controller according to claim 1, wherein when the servo motor control means includes feed forward control, the coefficient of the feed forward control is also switched to the value of the feed mode instructed to be switched.

Images