JPH04130501A - Origin position adjusting method and numerical controller therefor - Google Patents

Abstract

PURPOSE:To determine a grid shift amount required for adjusting a reference point with only operation of reference point return by measuring distance between a position detected with a machine position detector and a grid position. CONSTITUTION:The set position of a dog 2 is adjusted so that a deceleration signal *DECX with a limit switch 3 can be generated at a position at a dis tance of X from the reference point of a machine, L/2 for example, which is determined corresponding to a space L between grid points. Commanding a manual reference point return moves a machine table 1 at a low speed with the dog 2 depressed with the limit switch 3 for deceleration and stops the machine at a first grid position. At this time, a moving distance l of a moving part from the position where the limit switch 3 departs from the dog 2 up to the position where the moving part stops is measured and a grid shift amount d(=x-l) is calculated with a CPU 11. Thus, the grid shift amount required for adjusting the reference point can be determined with only one operation of the reference point return.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of adjusting the origin position to match the grid position with the machine origin and a numerical control device for the same, and particularly relates to a method for adjusting the origin position to match the grid position with the machine origin and a numerical control device for the same. The present invention relates to a method for adjusting the origin position necessary for an origin (reference point) return operation to match the origin with a machine-specific reference point, and a numerical control device therefor.

[Conventional technology]

A machine tool or robot (hereinafter simply referred to as a machine) that is controlled using a numerical control device requires an independent reference point for movement commands. The reference point is a point fixed to the machine that serves as a reference for movable parts of the machine such as tools.

Generally, a reference point is returned after the power is turned on, and machining is started from this reference point.

On the other hand, the motor that drives the movable part is controlled based on a feedback signal in response to a movement command, and a position detector is provided to form this feedback signal. In a normal position detector, the amount of movement of the movable part per rotation of the motor is known from grid signals generated at equal intervals. The reference point of the machine is also set based on this grid point.

[Problem to be solved by the invention]

However, when installing the machine, the traditional numerical control device! In this case, Niq manually adjusts the reference point of the machine, and this adjustment work is very difficult for the user, as it involves changing the position of the deceleration limit switch and actually measuring the amount of grid shift using a micrometer. It was annoying.

The present invention has been made in view of the above points, and has the following features:
It is an object of the present invention to provide an origin position adjustment method that can determine the grid shift amount necessary for reference point adjustment with only one reference point return operation, and a numerical control device therefor.

[Means to solve the problem]

In order to solve the above problems, the present invention uses a reference point return operation to calculate the deviation from the position of a specified grid point (grid position) among a plurality of grid points to a reference point specific to the movable part of the machine. The method for adjusting the origin position to be adjusted includes a first step of fixing the machine position detector at a position separated from the reference point by a distance X determined according to the spacing of the grid points, and a reference point return operation. A second step of measuring the distance l from the detection position by the fixed detector to the grid position based on a pulse generated in proportion to the drive amount of the drive means of the movable part, and a third step of calculating the deviation between the reference point and the reference point using an equation, and adjusting the origin position based on the deviation.

Further, the present invention provides a numerical control device that adjusts the origin position by aligning a reference point of a numerically controlled machine with a reference point specific to a movable part, and a storage means for storing the origin position specific to the machine as a reference point. a control means for controlling the movable part to stop at the reference point based on a deceleration limit switch and a dog provided on each coordinate axis of the machine; a measuring means that measures based on the elapsed time after the limit switch is restored; and generating the grid signal by the deviation between the measurement result of the measuring means and the distance to the reference point stored in the storage means. A numerical control device comprising: a grid shift means for shifting timing; and a command means for commanding reference point return using the grid signal specified by the deceleration limit switch as a reference point for numerical control. is provided.

[Effect]

so that the deceleration limit switch is restored at a position separated by a distance X (for example, L/2) determined according to the grid point spacing from the mechanical reference point connected to the numerical control device of the present invention; For example, fix the dog. When the numerical control device is switched to adjustment mode and the reference point return operation is performed manually to stop the moving parts of the machine at the first grid after the limit switch is restored, the above distance X and the deceleration limit are The amount of grid shift can be automatically determined from the moving distance of the movable part, which is measured based on the elapsed time after the switch is restored.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 is a diagram showing a numerical control device and part of a mechanical movable part for implementing the method of adjusting the origin position of the present invention. The processor 11 is a central processor for controlling the entire numerical control device (CNC), and executes control of the entire numerical control device (CNC) according to a system program stored in the ROM 12. ROM12 is EPROM or EE
PROM is used. An SRAM is used as the RAM 13, and various data such as temporal calculation data and display data are stored. The non-volatile memory 14 stores the tool correction amount, the cutting program 14a, various parameters 14b, etc., and since a battery-backed CNC 5 or the like is used, the contents are retained even after the numerical control device is powered off. As various parameters 14b, the reference position X of each coordinate axis of the mechanical movable part, the grid shift amount d, etc. are also stored.

PMC (Programmable Machine Controller) 15
receives commands such as the M function and the 1 function, converts them into signals for controlling the machine tool according to the ladder program 15a, and outputs the signals. It also receives limit switch signals from the machine side or various signals from the machine operation panel 7, and processes them using a sequence program. Signals necessary for processing are stored in the RAM 13 via the bus and read by the processor 11.

The display control circuit 16 converts data such as the current position, movement amount, and reference position X of each axis into a display signal and sends it to the display device 16a. The display device 16a displays this display signal. A CRT, liquid crystal display, or the like is used as the display device 16a. The keyboard 17 is used to input various data.

The position control circuit 18 receives a position command from the processor and outputs a speed command signal for controlling the servo motor 20 to the servo amplifier 19. The servo amplifier 19 amplifies this speed command signal and drives the servo motor 20. A pulse coder 21 that outputs a position feedback signal is coupled to the servo motor 20. The pulse coder 21 feeds back position feedback pulses to the position control circuit 18. Also, by differentiating the position feedback pulse from the pulse coder 21,
Generates a speed feedback signal. Instead of the pulse coder 21, a position detector such as a linear scale may be used. These elements are required for the number of axes, but
Since the configuration of each element is the same, only the X-axis is described here.

The input/output circuit 23 is for transmitting and receiving human output signals to and from the machine side, and the input/output circuit 23 is for transmitting and receiving human output signals to and from the machine side.
CX and *-LX are input to this input/output circuit 23. Further, a tool selection signal (T signal) for controlling tool exchange and the like are outputted from this input/output circuit 23 to a machine side control circuit (not shown).

The manual pulse generator 24 outputs a pulse train for precisely moving each axis according to the rotation angle, and is normally mounted on the machine operation panel 7, but is shown separately in this embodiment.

The figure shows a spindle amplifier for controlling the spindle,
The spindle motor etc. are omitted.

Further, although the description has been made using one processor here, depending on the system, a multiprocessor system configuration using a plurality of processors may be used to improve the processing speed.

A ball screw 6 is mechanically coupled to the servo motor 20 to control the movement of the machine table 1. That is, the machine table 1 moves in the X-axis direction by turning the pole screw 60 times.

A deceleration dog 2 is fixed to the lower part of the machine table 1. There is a limit switch 3 corresponding to this, which outputs a deceleration signal *DECX.

Further, at the bottom of the machine table 1 there is a dog 4 for the engine end, and a limit switch 5 corresponding to the dog 4 is provided.
There is. When the machine table 1 moves to the left, the dog 4 hits the limit switch 5 and a stroke end signal *
-Output LX.

Note that the symbol "*" in the signals *DECX and *-LX indicates that they are limit switch break contact signals. That is, this indicates that the contact signal is turned off when the dog 2.4 hits the limit switch 3.4.

Next, as a premise for adjusting the origin position of the present invention, an outline of the normal reference point return performed in the numerical control device will be described.

FIG. 3 is a diagram showing a procedure for manual reference point return using the grid method. Here, the grid method is a method in which a reference point is determined by an electrical grid (i.e., a grid) based on a one-rotation signal from a position detector.

First, on the machine operation panel 7, start with manual continuous feed mode (
J) and set the manual reference point return selection signal (ZRN) from signal J to high level. After that, select the feed axis and feed direction selection signal (+X) for the axis for which you want to return to the reference point.

-X, +Y, -Y, , , , ) and move the movable part in the direction of the reference point.

When the movable part approaches the reference point, a dog of the movable part steps on a limit switch fixed to the machine, and outputs a corresponding deceleration signal, for example *DECX, at a low level. As a result, the feed speed is once decelerated to zero, and then automatically becomes a low speed feed at the parameter-set reference point return speed PL.

The movable part then stops at the first grid point that occurs as it moves until the limit switch is restored. Furthermore, after confirming that the device has entered the in-position, the reference point return completion signal ZPX becomes high level.

FIG. 4 is a tight chart illustrating the outline of the method for adjusting the origin position of the present invention.

Prior to manual reference point return, a deceleration signal*
DECX is the machine-specific origin (machine reference point) P
, the distance X, which is determined according to the spacing of the grid points,
Here, the installation position of the dog is adjusted so that it occurs at a distance of L/2. After that, perform a reference point return simulation, measure the distance β that the movable part has moved from the position where the IJ Mitsutwitch leaves the dog until the movable part stops, and calculate the deviation between the measured value β and the distance X above. Find the grid shift fid.

When the manual reference point return is completed and the grid shift amount is automatically set, the operator turns off the power according to the alarm message and then turns it on again, so that the reference point coincides with the machine's unique origin.

Next, the software processing of the present invention will be described. 1st
The figure is a flowchart of one embodiment of the present invention. In the figure, the number following S indicates the step number.

[S1] Indicate the position where the limit switch leaves the dog for each axis as a distance from the origin unique to the machine. For example, the distance X is specified, such as L/2, according to the interval between grid points, and the position of the dog is thereby set.

[S2] Set the reference point return adjustment mode using parameters for each axis.

[S3] Command manual reference point return.

[S4] As a result, the machine table 1 moves in the reference point return direction at the rapid traverse speed Vr, and while the deceleration limit switch depresses the dog and moves at a low speed, the machine table 1 moves at the first speed after the limit switch is restored. Stop at the grid position. At this time, the distance l that the movable part has moved from the position where the limit switch leaves the dog until the movable part stops is measured. For this measurement, the movement amount pulse sent from the pulse coder 21 to the position control circuit 18 is used.

[35] CN, for example in CPU II inside C, the deviation d
(=X-1) is calculated and stored in the nonvolatile memory 14.

In this way, when the manual reference point return is completed and the grid shift amount is still set, an alarm to temporarily turn off the power is displayed on the display device 16a. If the deviation d has been calculated normally, the parameter that set the reference point return adjustment mode will be automatically canceled, and the next time the power is turned on, if the manual reference point return operation is performed, the above deviation will be calculated on the grid. Since it is set as a shift amount, the reference point coincides with the origin unique to the machine.

Although the explanation has been given using a mechanical table as an example of a mechanical movable part, it goes without saying that the present invention can be similarly applied to adjusting the origin position of other axes.

〔Effect of the invention〕

As explained above, in the present invention, the grid shift amount is automatically set inside the numerical control device, so the position of the limit switch for deceleration can be repeatedly changed, and the grid shift amount can be actually measured using a micrometer. The grid shift B necessary for adjusting the reference point can be determined with just one reference point return operation.

As a result, even if the machines to be controlled are different, the origin position can be easily adjusted, and a highly accurate reference point return operation is possible.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of an embodiment of the present invention, FIG. 2 is a diagram showing a numerical control device and part of a mechanical movable part for carrying out the method of adjusting the origin position of the present invention, and FIG. 3 is a diagram of the present invention. FIG. 4 is a time chart of an embodiment of the present invention. 1・---1-・Machine table 2.4 ・Dog 3.5 11 ・Limit switch ball screw Machine operation panel Processor OM AM Non-volatile memory PMC (Programmable Machine Controller) Patent applicant Fanuc Co., Ltd. agent Patent attorney Takemitaka Hattori ■ Figure 3

Claims (5)

[Claims] (1) The position of the grid point identified among multiple grid points by the reference point return operation (grid position)
In the method for adjusting the origin position to adjust the deviation from the reference point specific to the movable part of the machine, a first step of fixing the detector, and changing the grid position from the detection position by the fixed detector based on a pulse generated in proportion to the drive amount of the drive means of the movable part during the reference point return operation; a second step of measuring the distance l from the grid position to the reference point, and a third step of calculating the deviation between the grid position and the reference point from the formula d=X−l and adjusting the origin position based on this deviation. A method for adjusting an origin position, characterized by: (2) In the first step, the distance X is set to L/2 with respect to the interval L between the grid points, and the detector is fixed to a movable part of the machine.
How to adjust the origin position described. (3) The method of adjusting the origin position according to claim 1, characterized in that the deviation calculated in the third step is set as the grid shift amount d, and at the same time, the completion of the adjustment of the origin position is displayed. (4) In a numerical control device that adjusts the origin position by aligning a reference point of a numerically controlled machine with a reference point specific to a movable part, a storage means for storing the origin position specific to the machine as a reference point; a control means for controlling the movable part to stop at the reference point based on a deceleration limit switch and a dog provided on each coordinate axis of the machine; a measuring means for measuring based on the elapsed time after the restoration of the grid; and shifting the generation timing of the grid signal by the deviation between the measurement result of the measuring means and the distance to the reference point stored in the storage means. A numerical control device comprising: a grid shift means for controlling the deceleration limit switch; and a command means for commanding reference point return using the grid signal specified by the deceleration limit switch as a reference point for numerical control. (5) parameter setting means for switching between valid and invalid reference points stored in the storage means; and automatically disabling the parameter setting means when a reference point of the machine matches a reference point specific to the movable part. The numerical control device according to claim 4, further comprising means for: