JPH07129215A - Stored stroke limit stopping method for numerical controller - Google Patents

Abstract

PURPOSE:To eliminate the overrun quantity of the moving body positioning control of an NC device. CONSTITUTION:The stored stroke limit stopping method stops a moving body within a specific overrun quantity on the basis of a stroke limit position which is previously set in the memory of the numerical controller which positions the moving body driven by a servo motor, and the stroke limit position is compared with a target position and when the target position does not exceed the stroke limit position, the target position is inputted as a position command to a positioning speed command generating means 2 as it is, but when the target position exceeds the stroke limit position, on the other hand, the target position is corrected into a stroke limit position, which is inputted as a new position command to the positioning speed command generating means 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stored stroke limit stop method for limiting the amount of overrun in positioning a moving body based on a stroke limit position preset in a memory of a numerical controller.

[0002]

2. Description of the Related Art Conventionally, in a numerical control device (hereinafter abbreviated as NC), a current position of a moving body and a stroke limit position are compared with each other at a constant cycle, and the current position is a stroke limit position (hereinafter abbreviated as a limit position). When it was detected that the motor had exceeded the limit, the motor was stopped by giving a deceleration stop command to the motor. 5, 6, 7, and 8 are views for explaining the conventional technique. FIG. 5 shows an embodiment of a table feed servomotor to which a conventional stopping method by limit position monitoring means is applied. 2 is a positioning speed command creating means, 3 is a speed command integrator, 4 is a gain adjusting circuit, 5 is an amplifier circuit, 6 is a servomotor for a feed axis, 7 is a ball screw of a machine tool, 8 is a moving table of the machine tool, 9 Is a limit position monitoring means. Input data for positioning control is target position data, speed designation data, and limit position data. In FIG. 5, the speed command output from the positioning speed command creating means 2 is integrated by the limit position monitoring means 9, and the integrated value (that is, the movement amount) and the limit position data are compared every NC clock cycle T (ms). Then, when it is detected that the limit position data is exceeded, the process for setting the speed command from the next time to "0" is executed. FIG. 6 is a flowchart showing the functions of the positioning speed command creating means and the limit position monitoring means. Here, the speed command integrated value is compared with the plus side limit position data when the speed command direction is the plus direction, and is compared with the minus side limit position data when the speed command is the minus direction.

[0003]

However, in the prior art, as shown in FIG. 7, when monitoring at a cycle of T (ms), even if the speed command integrated value exceeds the limit position at a certain cycle, Since the speed command for the cycle is output, an overshoot occurs. As a result, the table 8 stops beyond the limit position as shown in FIG. The present invention aims to reduce this overshoot amount to zero.

[0004]

In order to solve the above problems, the present invention relates to a numerical control device for positioning a moving body driven by a servo motor, and a stroke preset in a memory of the numerical control device. In a stored stroke limit stop method in which the moving body is stopped within a predetermined overrun amount based on a limit position, the target position and the stroke limit position are compared, and the target position exceeds the stroke limit position. If not, the target position is input as it is to the positioning speed command creating means as a position command, and when the target position exceeds the stroke limit position, the target position is corrected to the stroke limit position,
The corrected target position is input to the positioning speed command creating means as a new position command.

[0005]

By the above means, even if the target position commanded in advance exceeds the limit position, the commanded target position is corrected to the limit position. Can be positioned.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, 1 is a target position correction means, 2 is a positioning speed command creating means, 3 is a speed command integrator, 4 is a gain adjusting circuit,
Reference numeral 5 is an amplifier circuit, 6 is a feed axis servomotor, 7 is a ball screw, and 8 is a moving table of a machine tool. Next, the operation of this embodiment will be described. In case of positioning command, target data, limit position data,
There is speed specification data. In the target position correction means No. 1, the target position data and the limit position data are compared, and if the target position does not exceed the limit position, the target position data is directly input to the positioning speed command creating means 2 as a position command. . When the limit position is specified in front of the target position, the target position data is corrected to the same data as the limit position, and the corrected target position data is input as a position command to the positioning speed command creating means. FIG. 2 is a flow chart showing the functions of the target position correcting means and the positioning speed command creating means. In the figure, the target position data and limit position data are compared in the first positioning command correction operation of the T (ms) cycle, and only when the target position data exceeds the limit position data,
Correct the target position data to the limit position data value.
At this time, the limit position data is compared with the plus side limit position data when the target position is plus, and is compared with the minus side limit position data when the target position is minus. In this way, the target position is made the same as the limit position only when the target position exceeds the limit position, so that the table of the moving body stops at the limit position. In the present invention, the target position is corrected by the target position correcting means before the speed command is output as shown in FIG. 1, so that the speed command up to the limit position is reached as shown in FIG. As a result, the vehicle is positioned at the limit position when the overshoot amount is zero as shown in FIG.

[0007]

As described above, according to the present invention, the target position is corrected to the limit position even when the commanded target position exceeds the limit position. Can be accurately positioned with the quantity'zero '.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flow chart showing the functions of a target position correcting means and a positioning speed command creating means according to the present invention.

FIG. 3 is a diagram for explaining the effect of the present invention.

FIG. 4 is a diagram for explaining the effect of the present invention.

FIG. 5 is a block diagram to which a stopping method by a stroke limit position monitoring means of a conventional technology is applied.

FIG. 6 is a flowchart showing the functions of a positioning speed command creating means and a stroke limit position monitoring means in the prior art.

FIG. 7 is a diagram illustrating an overshoot amount that occurs in a scan cycle according to the related art.

FIG. 8 is a diagram for explaining an overshoot amount by a target stop position monitoring unit according to a conventional technique.

[Explanation of symbols]

 1 Target Position Correcting Means 2 Positioning Speed Command Creating Means 3 Speed Command Integrator 4 Gain Adjusting Circuit 5 Amplifier Circuit 6 Feed Axis Servo Motor 7 Ball Screw 8 Table 9 Limit Position Monitoring Means

Claims (1)

[Claims] 1. A numerical control device for positioning a moving body driven by a servomotor, wherein the moving body is moved within a predetermined overrun amount based on a stroke limit position preset in a memory of the numerical control device. In the stored stroke limit stop method for stopping, the target position and the stroke limit position are compared, and when the target position does not exceed the stroke limit position, the target position is used as it is as a position command for a positioning speed command. Input to the creating means, when the target position exceeds the stroke limit position, the target position is corrected to the stroke limit position,
A method for stopping a stored stroke limit of a numerical control device, characterized in that the corrected target position is inputted as a new position command to the positioning speed command creating means.