JPH06106457A - Movable part position detecting method and detecting device in working machine - Google Patents

Abstract

PURPOSE:To carry out proper working by detecting a relative position easily without providing a sensor and the like in a tool of a working machine or a work. CONSTITUTION:In a movable part position detecting method in a working machine to carry out working by moving a movable part 9 to a fixed part or an another movable part while controlling a driving means 11 by a command value from a control part 3, an actual moving value of a movable part 19 is detected by a position detecting means 13, and a difference between this actual moving value and the command value is found, and a movable part 11 detecting position where this difference is increased more than a preset value, is detected as a contact point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting the position of a movable part in a processing machine, and more particularly to a processing for detecting the position of a workpiece which moves relative to a tool of the processing machine. TECHNICAL FIELD The present invention relates to a movable part position detection method and a detection device in a machine.

[0002]

2. Description of the Related Art Conventionally, when a work is machined by a processing machine, it is obvious that proper machining cannot be performed unless the exact position of the machined work with respect to the tool is grasped.

Therefore, when the work moves relative to the tool, a sensor, a limit switch, or the like is attached to the tool side or the side that clamps the work to detect their relative positions. It is common.

[0004]

However, in such a conventional technique, there is a problem that the cost of the detection device becomes expensive because a sensor or the like has to be provided on the work or tool which is a moving body. ing.

An object of the present invention is to pay attention to such a conventional technique, and to easily detect the position of a movable part without providing a sensor or the like on a tool or a work of a processing machine, for example. Accordingly, it is an object of the present invention to provide a movable part position detection method and a detection device in a processing machine capable of performing appropriate processing.

[0006]

In order to achieve the above-mentioned object, a movable part position detecting method and a detecting device in a processing machine according to the present invention, a command value from a control part controls a driving means, A method for detecting the position of a movable part in a processing machine, in which the movable part is moved with respect to a fixed part or another movable part, is used. It is characterized in that a difference between the value and the command value is obtained, and the detection position of the movable part, which has increased from the preset value, is detected as the contact point.

In order to carry out the above detection method,
A processing machine comprising a movable part provided movably, a driving means for moving the movable part, and a control part for controlling the driving means, the position detecting means detecting a position of the movable part. In addition to the above, the control unit is provided with a comparison unit for comparing the difference between the position detected by the position detection unit and the position commanded by the control unit to the drive unit.

[0008]

According to the movable part position detecting method and the detecting device in the processing machine according to the present invention, since the driving means moves the movable part in response to the command from the control part, the position detecting means can detect the position of the movable part. When the movable portion comes into contact with the fixed portion or another movable portion due to the movement of the movable portion, the movement of the movable portion is blocked, so that the position instructed by the control unit and the position detected by the detection means are Difference occurs. The comparison means provided in the control unit compares this difference with a preset value, and the detected position of the movable portion that has increased can be detected as the contact point.

Therefore, by using the detected point as a reference, for example, the interval between the work and the tool is determined, or the origin of the work positioning is set, whereby accurate machining can be performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of the configuration and control contents of an NC control device 1 which is the main part of the present invention will be explained based on FIG. 1, and then concrete examples will be explained.

The NC control device 1 includes a main control section 3, a position control section 5 connected to the main control section 3, and the position control section 5.
It has a speed controller 7 connected to.

A drive means 11 such as a servomotor for moving a movable part 9 holding a tool or the like is connected to the NC control device 1, and the drive means 11 is connected to the drive means 11. Internal position detection means 13 such as an encoder provided is also connected. The movable part 9 is, for example, a work W as a fixed part or another movable part.
On the other hand, it is moved by being screwed into, for example, a ball screw which is rotated by the driving means 11.

Further, the main control section 3 controls the entire processing machine by NC.
In order to control, a movement command (command pulse) to the movable part 9 such as a tool is issued to the position control part 5.

The position control section 5 has an error counter 15 as a comparison means directly connected to the main control section 3, and a speed command conversion section 17 for converting a movement command, which is a digital amount, to the speed control section 7. And a position detection signal conversion unit 19 which receives a position signal from the internal position detection unit 13 to convert it into a detection pulse and transmits it to the error counter 15. The speed control section 7 is for controlling the speed of the driving means 11 in accordance with a command from the position control section 5. With the configuration as described above, the movement of the movable portion 9 is controlled as follows.

A movement command is issued from the main control unit 3 to the error counter 15 of the position control unit 5, and the movement command, which is a digital amount, is converted and given to the speed control unit 7. The speed control unit 7 controls the driving unit 11 based on the movement command to move the movable unit 9. On the other hand, the internal position detection means 13 provided in the drive means 11 sends a signal corresponding to the rotation of the drive means 11 to the position detection signal conversion section 19 of the position control section 5.

Here, the error counter 15 is connected to the main controller 3
The difference between the command position from the position detection signal and the detection position from the position detection signal conversion unit 19, that is, the position deviation amount is held (see the following equation), and the position deviation amount = feed speed (mm / min) / 60 / loop gain (1 / Sec) ... 1 The driving means 11 is controlled so as to rotate at a speed proportional to the position deviation.

The loop gain represents the characteristics of the servo mechanism, and the higher the loop gain value, the better the adaptability.

That is, when the movable part 9 comes into contact with the work W or the like, its movement is blocked, the detection pulse generated by the position detection signal conversion part 19 is reduced, and the position deviation amount is increased by the equation 1.

The movable part 9 corresponding to the detected increase point
Is detected as a contact point of the work W or the like, that is, the position of the work W or the like, and by using this as a reference point, the positional relationship between the movable portion 9 and the work W can be accurately grasped. It becomes possible to perform accurate processing.

Further, since it is not necessary to provide a sensor, a limit switch or the like on the movable part 9 or the like, it is advantageous in terms of cost.

The detection of the work position in a concrete processing machine will be described below. Here, since all the processing machines are general ones, their structure and operation will be described only in outline, and common components will be denoted by common reference numerals and description thereof will be omitted.

First, FIG. 2 shows a moving machine position detecting method and a detecting device in a working machine according to the present embodiment.
The example used for is explained.

In this drilling machine 21, a machining head 25 as a movable part is provided at the upper end of a frame 23 having an overall C shape so as to be movable up and down, and at the lower end of the machining head 25, a high speed rotation is made by a rotation driving means not shown. A drill 27 is provided as a tool for working. The processing head 25 is moved up and down by a servo motor 29 as a driving means, and the servo motor 29 is the NC controller 1.
It operates by a command from the speed control unit 7 therein.

The servo motor 29 is provided with an encoder 31 as an internal position detecting means, and the encoder 31 is connected to the position detection signal converting section 19 in the NC control device 1.

Further, a work table 33 for holding the work W is provided at a middle height position of the frame 23 so that the desired position of the work W is positioned below the drill 27. is there.

The internal configuration of the NC control device 1 is configured as described above, and therefore its explanation is omitted.

With the above construction, the rotation driving means (not shown) rotates the drill 27 provided on the machining head 25, and the servo motor 29 lowers the machining head 25 to position it on the work table 33. The work W is drilled.

At this time, when the drill 27 comes into contact with the work W and the lowering of the machining head 25 is prevented, the NC controller 1
Since the error pulse counted by the error counter 15 of 1 increases, this point can be detected as a contact point with the work W. At this detected position, a mechanical error such as backlash of the feed screw of the processing head 25 is canceled, so that the position of the work W can be accurately detected.

As a result, even when the drills 27 having different lengths are used for drilling, it is sufficient to lower the plate thickness of the work W from the detected position by an amount corresponding to the plate thickness.
The machining head 25 is automatically operated only by inputting it to the C control device 1.
The vertical movement range of can be set.

Next, an example in which the movable part position detecting method and the detecting device in the processing machine according to the present embodiment are used in the laser processing machine 35 will be described with reference to FIG. Where N
Since the C control device 1 is as described above, its explanation and illustration are omitted.

The laser beam machine 35 irradiates the work W with the laser beam LB condensed by the lens 39 in the machining head 37 from the nozzle 41 attached to the lower end of the machining head 37, thereby cutting or cutting. The work W is subjected to thermal processing such as welding.

Therefore, in order to perform efficient and accurate thermal processing, the relationship between the distance between the lens 39 and the work W and the focal length L of the lens 39 becomes important. Therefore, the servo motor (not shown) for lowering the processing head 37 is controlled to adjust the distance between the lens 39 and the work W.

As shown in the figure, the lens 39 and the nozzle 41
Since the distance A to the tip is constant, the nozzle 41
If the distance B from the tip to the work W can be grasped, the focal length L can be accurately controlled.

Therefore, the processing head 37 is once lowered. At this time, when the nozzle 41 comes into contact with the work W, the processing head 37 is prevented from descending, so that the error pulse increases in the NC control device 1 and this point can be detected as a contact point with the work W. By raising the processing head 37 from the detected position by B in the figure, the position of the lens 39 can be accurately positioned at a predetermined position, so that desired thermal processing can be performed. In this case, the nozzle 41
Since the nozzle 41 itself is adversely affected by directly contacting the workpiece W with the workpiece W, it is conceivable to provide a contact portion with the workpiece W outside the nozzle 41. At that time, the distance between the tip of the nozzle 41 and the work W is previously input to the NC device as a constant Δx, for example.

In addition to the above-described embodiments, the present invention can be widely used for automatic origin finding of tools in lathes, V-cuts, machining centers, etc., and setting of a positioning reference for a work W.

Further, the present invention can be applied to a processing machine in which a tool or a work W is moved and is controlled to move to the opposite side when hitting an obstacle.

Further, in each of the above embodiments, the case where only one of the tool and the work W moves has been described, but the same applies to the case where both the tool and the work W move. Although the example of the encoder or the resolver provided in the driving means as the position detecting means has been described, it is also possible to apply it in a full closed loop using an external position detector such as a linear scale.

[0038]

The method and apparatus for detecting the position of a movable part in a processing machine according to the present invention have the above-described structure. When the movable part moves, the movable part becomes a fixed part or another movable part. When they come into contact with each other, the movement of the movable part is blocked, so that a difference occurs between the position instructed by the control part and the position detected by the detection means. This difference is compared by the comparison means provided in the control unit, and the increased point can be detected as the point at which the movable section abuts the fixed section or another movable section.
It is possible to accurately detect the position of the movable portion without providing an external mechanical sensor or limit switch.
In addition, by accurately detecting the position of the movable portion, it is possible to perform accurate processing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a movable part position detection method and a detection device in a processing machine according to the present invention.

FIG. 2 is an explanatory view showing an example in which the movable part position detecting method and the detecting device in the processing machine according to the present invention are used in a drilling machine.

FIG. 3 is an explanatory view showing an example in which a movable part position detecting method and a detecting device in a processing machine according to the present invention are used in a laser processing machine.

[Explanation of symbols]

 1 NC Control Device (Control Unit) 25, 37 Machining Head (Movable Part) 27 Drill (Tool) 29 Servo Motor (Drive Means) 31 Encoder (Position Detection Means) 41 Nozzle (Tool) W Work

Claims (2)

[Claims] 1. A method for detecting a position of a movable part in a processing machine, wherein a movable part is moved with respect to a fixed part or another movable part by controlling a drive means by a command value from a control part, An actual movement value of the movable portion is detected by the position detecting means, and a difference between the actual movement value and the command value is obtained,
A work position detection method in a processing machine, wherein a detection position of a movable part in which this difference has increased above a preset value is detected as a contact point. 2. A processing machine comprising a movable part which is movably provided, a drive means for moving the movable part, and a control part for controlling the drive means, wherein the position of the movable part is changed. In the movable machine, the position detecting means for detecting is provided, and the control means is provided with comparing means for comparing the difference between the position detected by the position detecting means and the position commanded by the control means to the drive means. Part position detection device.