JPS5866121A - Deviation phase modulator for numerical controlling device - Google Patents

Abstract

PURPOSE:To move a work accurately, by detecting the movement of the work due to a command of a controlling computer and generating a servo command signal for backlash correction on a basis of the work moving command. CONSTITUTION:A deviation phase modulator 22 is connected to the output side of a controlling computer 21. The output of the deviation phase modulator 22 is connected to a resolver 26 through a resolver exciter 23, and the deviation phase modulator 22 supplies a signal SC to a servo unit 24 to drive a motor 25. The deviation phase modulator 22 receives a feedback signal from the resolver 26 and compares the phase of the servo command signal SC, which is outputted to the servo unit for every shaft by a moving signal (signal instructing a work 27 to move to the plus (+) or minus (-) side) of the work to every shaft, with that of a standard signal to move the work 27 to the plus (+) or minus (-) side. Thus, directions of axial movement of the work 27 are monitored successively to correct always the backlash.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deviation phase modulator for a numerical control device, and particularly to a deviation phase modulator having a backlash correction function.

Generally, numerical control work a# has a feeding mechanism composed of screws and nuts! In theory 1, when the feed direction changes, an error occurs between the command value and the command value due to backlash. In order to eliminate this error, the numerical control device a needs to have a so-called backlash correction function.

In conventional numerical control devices, backlash correction is processed by software in a parameter-based manner.

According to this method, the workpiece movement command is sent to the same axis L/)
7 When the force direction is opposite to the direction of the previous workpiece movement command B
A movement It for backlash correction is added to the original movement layer, and a movement command having the following contents is output from the control calculator.

However, such conventional methods have the following drawbacks.

That is, it is necessary to constantly monitor the work movement command, which is the basic operation of the numerical control device, inside the control computer, which reduces the processing efficiency of the control JF computer. However, in diagonal line cutting where the feed direction changes by 180 degrees as shown in Figure 1, it is possible to perform backlash correction at the moving direction switching point 1, but when cutting a circle as shown in Figure 2, In cutting, the workpiece movement direction detecting means at the movement switching point 11 is expensive, and backlash correction cannot be performed using software.

The present invention was devised in view of the points of concern regarding conventional backlash correction, and it is possible to improve the processing efficiency of a control computer and to always perform backlash correction even in cases such as circular cutting. The object of the present invention is to provide a differential phase modulator for a control machine.

The deviation phase fTs device of the numerical control device of the present invention includes a first means for detecting a change in the axis movement direction based on a workpiece movement command output from a control calculator, and a change in the axis movement direction by the first means. and a second means for performing backlash correction based on the workpiece movement command and forming and outputting a servo command signal when the workpiece movement command is not detected.

The present invention will now be described in more detail with reference to the accompanying drawings.

Fig. 3 shows the position control section of the i & value control device, in which a deviation phase modulator 22 is provided at the output 111 of the control calculation Ja21, and the output side of the deviation phase modulator 22 is connected to one side and is connected to the resolver exciter. 23, and a servo unit 24 on the other hand.

The output side of the resolver exciter 26 is connected to the resolver 26, and the output side of the servo unit 24 is connected to the motor δvc. Further, the reference numeral 27 indicates a workpiece.

In backlash correction using the conventional method, a control computer 21 determines whether or not backlash correction is necessary, and if necessary, generates a work hyperactivity command 12 that does not add correction filter, and responds accordingly. However, in the present invention, the control computer only generates the workpiece movement command according to the user program, and the control computer uses the deviation phase for backlash correction. Due to the newly added function to the modulator 22, it will be processed as hardware.

The deviation phase modulation dg of the present invention is the phase of the servo command signal SC output to the servo unit 24 for each valley axis based on the workpiece movement signal for each axis (+ side or - (signal that commands movement to 1111)). The signal is compared with the standard signal and moved to the + side or -1llll.

Figure 4 shows #! Deviation phase modulation a22 of the present invention shown in Figure 5
This figure shows an example in which a set of ten-direction movement commands Xp for the X-axis and one-direction movement commands Xn for the X-axis are input for each axis. The timing TS transmits the ten-direction movement command Xp and one-direction movement command Xn with a deviation phase fi.
This is a timing signal to be taken into the IL unit 22. The standard signal counter 32 is for a standard signal that serves as a reference for comparing the phase of the servo command signal SO for each axis. The X-axis signal counter 33 is a counter for servo command signals (SLSC), and is provided for each axis. It has a function of adding data to the counters 52 and 55 in response to the command Xn, and is 1/-h.

As mentioned above, the deviation phase modulator constitutes a one-pole counter, and the displacement between the standard (N repair counter 32 and x@small number counter 33 provided for each axis) is the workpiece movement command It does not change when (Xp, Xn) is not issued, but it changes when a workpiece movement command is issued.

FIG. 5 is a diagram showing the phase relationship of the servo command signal with respect to the X-axis. In FIG. Figure 5 (
1) XC) d This is an example of the servo command signal SO. Since the contents of the X-axis signal counter 33 for each axis change according to the upward movement commands Xp and Xn, the phase of the servo command signal SC has a phase difference of [-] with respect to the servo command standard signal. Become.

That is, the deviation position i/l modulator 22 controls the phase of the keep command signal SC by controlling the addition amount of the X-axis signal counter 55 based on the workpiece movement command.

FIG. 6 is a block diagram showing an example of hardware for performing backlash correction according to the present invention. The memory 51 is for storing the previous movement direction of each axis, and the memory 52 is for storing the current workpiece movement command WS.

The comparator 55 compares the previous moving direction and the current moving direction for each axis, and detects whether or not they are the same for each axis. If the moving directions are different, backlash correction is required, so the correction ff1ff constant fi 55 fetches backlash correction amount data from the memory 54,
Output as backlash correction 1k BS. If the moving directions are the same, backlash correction is not necessary.Ninthly, the correction amount setter 56 outputs the backlash correction amount BS(-0) whose content is the correction amount '4. The backlash correction jiBs output in this way is added to the X@ signal counter in the deviation phase modulator 22, and the servo command 1# SC to which backlash correction has been applied is output from the % deviation phase modulator 22. Ru. Finally, the contents of memory 52 are shifted to memory 51.

1 [E! ] operation ends. In addition, in the present invention, -
This movement command corresponds to the minimum setting unit of workpiece movement, so each time a workpiece movement command of the minimum setting unit is issued, it is determined whether backlash correction is necessary or not, and if necessary, correction is added. It will be done. Therefore, according to the present invention, backlash can be corrected even in cases such as circular cutting shown in FIG. 2, which cannot be corrected using conventional software methods.

As is clear from the above description, according to the present invention, by adding simple hardware to the conventional circuit, the program capacity t of the control calculator can be reduced, and the Even in the case of circular cutting, the direction of movement of the shaft is continuously monitored, so that backlash correction can be performed at all times.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing an example of cutting using a numerically controlled 1 machine tool, FIG. 3 is a block diagram showing an example of a position control section of a numerically controlled device, and FIG. A block diagram showing an example, FIG. 5 shows the deviation phase amount of the present invention! ! #
Figure 6 shows an example of the servo command signal output from the servo controller.
The figure is a block diagram showing an example of a case where the deviation phase modulator of the present invention is configured by hardware. 21... Control computer, 22... Deviation phase modulator,
24...Servo unit, 31...Count control section, 32...For standard signal, 33...
X-axis 1g counter, 51.52.54...Memory % ratio MiM, 55.56, correction jt & 51iua, S
C-servo command old, Xp...ten direction movement command, X
n...One-way movement command %vVS...Workpiece movement command doubled, BS...Backlash correction amount. Agent Patent Attorney Bo 1) Li Xin Fig. 4 Aman Fig. 5

Claims (1)

[Claims] @1 means for detecting a change in the axis movement direction based on a workpiece movement command output from a control computer; and when a change in the axis movement direction is detected by the first means, the workpiece movement direction is also detected. Backlash correction is applied to 1. and second means for forming and outputting a servo command signal.