JPS6165309A - Output system for reference point position signal - Google Patents

Abstract

PURPOSE:To facilitate position detection in case of an abnormal stop by outputting a reference point signal when the tool of a numerically controlled machine tool returns into a nearby area including coordinate points before and behind a reference point if the tool is commanded to return to the reference point automatically. CONSTITUTION:A teaching playback type robot has a G28 mode in which an automatic return to the reference point is commanded as one of control functions of NC commands, and a hand is returned to the reference point determined separately from a program origin for determining the position of the hand within its operation range. When it is judged that the specified mode of the robot is G28, data necessary for path control over the hand are read out according to reference point data and the robot then commands an interpolation start to drive the hand so that it returns to the reference point automatically. A current position register generates the reference point position signal showing the hand is within the nearby area of the reference point (range + or -x). The data + or -x are set optionally.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reference point position signal output method in a teaching playback robot.

(Prior art) Numerical control machine tools for robots (hereinafter referred to as NC machine tools) have conventionally used pulse generators to detect the position of each axis for interpolation movement. Prior to automatic operation, preparatory work such as teaching robot command data is performed using the fixed position as a reference point (also referred to as a reference point). In other words, when attempting to machine a workpiece according to the robot's command data, the path conditions for automatically moving the tool change depending on the relationship between the workpiece and the tool. By giving timely information to the servo system from the program,
It is possible to eliminate the discrepancy between the taught tool movement trajectory and the actual tool movement trajectory. For example, when a tool repeatedly draws the same movement path, by setting the reference point at a point where the tool can be easily moved to that position, the reference point position signal will be sent when the tool reaches that reference point. The robot outputs the following command data, and only when it receives that signal, the robot gives the next command data and moves forward.

(Problem to be Solved by the Invention) In such a conventional reference point position signal output method, when a failure occurs in a robot arm, work feeder, etc., an alarm is generated, the tool stops, and the When the stop position is exactly in the process of executing a return command to the reference point, the tool has reached the vicinity of the reference point, but the reference point position signal is not generated, and the arm or work feeder failure has been recovered. Even afterwards, the operator had to manually return the tool position to the reference point.

The present invention has been made in view of the point -1-, and by expanding the output function of the reference point position signal, the next command data can be smoothly transmitted after failure recovery without bothering the operator when an alarm occurs. The object of the present invention is to provide a reference point position signal output method that operates a tool according to the following.

(Means for solving the problem) The present invention provides numerical control T
In a method in which a tool of a machine tool is commanded to automatically return to its reference point and a reference point signal is output when the tool returns to the reference point, the vicinity including predetermined coordinate points before and after the reference point. 17. The method includes means for setting an area, and means for determining that the tool has returned to the set neighborhood area, and outputs a reference point signal when the tool returns to the set neighborhood area. Provided is a reference point position signal output method characterized by the following.

(Function) The reference point position signal output method with this configuration is such that when a tool of a numerically controlled machine tool is commanded to automatically return to its reference point, it outputs predetermined coordinate points before and after the reference point. Since the reference point signal is output when the tool returns to the vicinity area including the reference point, the position of the tool that has come to an emergency stop near the reference point can be easily detected.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a teaching play bank type robot, and the side line portion is the operating range of the hand.

In order for this hand to automatically perform a predetermined sequence of operations using an NC control unit (not shown), the operator must move the robot's hand to teach the operation sequence as a preparatory work in advance, and then use the NC control unit. It is necessary to store the working order, position, moving speed, and other information of the hand in a memory circuit such as a RAM within the unit. Thereafter, when the robot automatically operates, the taught motion is reproduced (playpacked) according to the data read from the memory circuit, and automatic work is performed by the hand. At this time N
The data output as the C command is read out in blocks, and one of the control functions of the NC command is the G28 mode that specifies automatic return to the reference point. This is a specified mode for unconditionally returning the hand to a reference point determined separately from the program origin for determining the hand position within the hand's operating range, and
For example, when the hand passes this reference point, if it is desired to execute a command to release the workpiece that the hand has been holding, the flowchart shown in FIG. 2 is executed.

In FIG. 2, in step a, it is determined whether the designated mode of the robot is G28 or not. If it is determined that it is G28, data necessary for hand path control is read out according to the reference point data (step b ). Next, the robot commands the start of interpolation and starts driving the hand to automatically return to the reference point (step C).

The reference point data is given to the reference point return circuit provided for each control axis by the dimension word following the preparation function word 028. On the other hand, since the robot always detects the current position of the hand using either the incremental method or the absolute method, it is necessary to set a nearby area that includes a predetermined coordinate point before and after the reference point in the reference point return circuit. , a certain number of count pulses input to the current position register are canceled, and even before the current position register reaches the range of ±X of the coordinate point data, the hand is at the reference point even before it matches the coordinate point data. The configuration is such that it can be determined that the object has returned to the vicinity area.

Therefore, if an abnormality occurs in the robot's hand, its control mechanism, work feeder, etc., and an abnormal stop other than the programmed operation occurs in the vicinity of the reference point, the process moves from step d to step e, and A point position signal is generated. In step d, as long as the current position register has not reached the ±X range of 11 of the reference point data, the process returns to step C and the hand interpolation operation continues.

The data ±X when setting the above-mentioned nearby crawling castle is determined according to the next operation command at the reference point, and is determined as appropriate depending on the need for precision in position control of the workpiece and hand. You can select .

In this way, the reference point position signal is generated in step e, so even if the robot stops abnormally, it can easily detect the position of the hand, and the next command data is given to the servo system to drive the hand. Ru. therefore,
After the failure of the hand, work feeder, etc. is recovered, it is possible to immediately move on to the operation of the next block.

(Effects of the Invention) As described above, according to the present invention, by expanding the output function of the reference point position signal, the next command data can be smoothly transmitted after failure recovery without bothering the operator in response to an alarm occurrence. The receiver can provide a reference point position signal output method that has effects such as being able to operate the tool.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the operating range of the robot, and FIG. 2 is a flowchart showing an embodiment of the present invention. Patent applicant Representative of FANUC Co., Ltd. Patent attorney Minoru Tsuji (1 other person)

Claims (1)

[Claims] In a method in which a tool of a numerically controlled machine tool is commanded to automatically return to its reference point, and a reference point signal is output when the tool returns to the reference point, predetermined coordinate points are set before and after the reference point. and means for determining that the tool has returned to the set neighborhood area, and outputs a reference point signal when the tool returns to the set neighborhood area. A reference point position signal output method characterized by the following.