JPS636604A - Numerical control system - Google Patents

Abstract

PURPOSE:To attain a highly accurate numerical control system by detecting the temperature of a driving part with a temperature sensor and compensating the control of the driving part by a numerical controller in response to the change of said detected temperature. CONSTITUTION:This numerical control system consists of a numerical controller 1, a drive motor 7 which is driven by a drive amplifier 6, a detector 8 for rotational speed and angle of the motor 7, a table 13 which is moved by a ball screw 12, etc. The controller 1 includes a tow 3, a positioning function parameter 4, a position loop gain 5, etc. Here a temperature sensor 14 is attached at a contact between the screw 12 and the able 13. Then this control system divides the correction value of the ball screw pitch P to be changed in response to the thermal expansion of the screw 12 by the expansion factor and the temperature data feedback 15 out of said parameter 4. Thus the pitch P is corrected. Thus the temperature change can be compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a numerical control system that can improve the cutting surface accuracy and cutting shape accuracy of numerically controlled machine tools and the like.

[Conventional technology]

FIG. 2 is a diagram showing a conventional semi-closed loop control numerical control system. In this figure, 1 is a numerical control device, 2 is a command given to the numerical control device 1, and 3 is a positioning control system based on the command 2. The constant tau (TAU) required to
), 11 is a positioning function parameter necessary to calculate the tau 3, 5 is a position loop gain which is an amplification element of the numerical control device 1, and 6 is a parameter for receiving and amplifying a command from the numerical control device 1. 7 is a drive motor driven by the power from the drive amplifier 6; 8 is a detector for detecting the rotational speed and rotation angle of the drive motor 7;
10 is a position data feedback that is returned from the detector 8 to the numerical control device 1; 11 is a coupling for controlling the rotation of the drive motor 7; 12 is the coupling A ball screw 11 is connected to the ball screw 11, and a table 13 is moved by the ball screw 12.

Next, the operation will be explained.

In the numerical control device 1, the tau 3 is calculated based on positioning function parameters 4 such as the gear ratio of the detector 8 necessary for positioning according to the given command 2, the amount of movement per one pulse of the command 2, and the ball screw pitch. The difference between this value and the current position data of the drive motor 7 (position data feedback 10) is integrated and amplified by the position loop gain 5,
Pass it to drive amplifier 6.

Command 2 is Dl, Tau 3 is TAU, position detection gear ratio is X,
The amount of movement per pulse is a, and the pole screw pitch is P2.
If the position data feedback 10DI, the position loop gain 5 is Kp, and the value passed to the drive amplifier 6 is ε, then ε-, Σ(DI-TAU-DO...(1)T
AU=Ding・α ・・・・・・・・・・・・・・・(
2).

Next, the rotation of the drive motor driven by the drive amplifier 6 is transmitted through the coupling 11 and rotates the ball screw 12.

Since this rotational motion of the ball screw 12 is transmitted as a linear motion, the table 13 attached to the ball screw 12 moves left and right.

During this series of operations, a detector 8 attached to the rotating shaft of the drive motor 7 detects the motor rotation speed and motor rotation position, and the motor rotation speed is detected by the speed data feedback 9.
The motor rotation position is returned to the drive amplifier 6 for speed loop control, and the motor rotation position is returned to the drive amplifier 6 as position data feedback 1.
It is returned to the numerical control device 1 as o and position loop control is performed.

[Problem that the invention seeks to solve]

In the conventional numerical control system as described above, when the pole screw pitch P changes due to thermal expansion of the ball screw 12 due to temperature change and the actual movement amount for each pitch changes, there is no compensation function, so the movement distance of the table 13 is changed. There was a problem that an error occurred.

The present invention was made to solve this problem, and an object of the present invention is to provide a numerical control system that can compensate for thermal expansion due to temperature changes.

[Means for solving problems]

The numerical control system according to the present invention includes a temperature sensor that detects temperature in a drive unit that causes errors due to temperature changes, and the numerical control device compensates for control of the drive unit in response to temperature changes detected by the temperature sensor. It is configured to do so.

[Operation] In the present invention, the numerical control device compensates the control of the drive unit in response to a change in temperature detected by a temperature sensor provided in the drive unit.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the numerical control system of the present invention. In this diagram, the same reference numerals (and similar parts are shown) as in FIG. 15 is a temperature data feedback, which represents the temperature of the ball screw 12 detected by the temperature sensor 14.

In the numerical control system configured as shown in FIG. The original pole screw pitch P is corrected based on the expansion coefficient and temperature data feedback 15 suitable for the material of 12. If this correction value is Po, then the above-mentioned equations (1) and (2)
The formula is e1=, Σ(D + ・T A U s D
tL---(3) X T A U 1-B-F1'l・α ・・
(4) becomes.

That is, even if the pole screw pitch P increases due to thermal expansion, the correction value P0 is added to the pole screw pitch P so that the motor rotation speed is reduced by an appropriate amount. Along with this, TAUl is reduced by a predetermined amount, and as a result, the value ε output to the drive amplifier 6 is also reduced by an appropriate amount, thereby compensating the control according to the expansion and contraction of the ball screw 12 due to temperature changes. be able to.

In the above embodiment, the temperature sensor 14 is connected to the ball screw 1.
2 and the table 13, but it may also be provided at the end of the ball screw 12.

In addition, in the above embodiment, the pole screw pitch P has a correction value P0.
Although a case has been described in which the control is compensated by adding , the gear ratio

〔Effect of the invention〕

As described above, this invention includes a temperature sensor that detects temperature in a drive unit that causes errors due to temperature changes, and a numerical control device that compensates for control of the drive unit in response to temperature changes detected by the temperature sensor. This configuration has the advantage that highly accurate control can be performed regardless of temperature changes.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the numerical control system of the present invention, and FIG. 2 is a diagram showing a conventional numerical control system. In the figure, 1 is a numerical control device, 2 is a command, 3 is a controller,
4 is a positioning function parameter, 5 is a position loop gain, 6 is a drive amplifier, 7 is a drive motor, 8 is a detector, 9 is a speed data feedback, 10 is a position data feedback, 11 is a coupling, 12 is a ball screw, 13
is a table, 14 is a temperature sensor, and 15 is a temperature data feed pack. - The same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] In a numerical control system having a drive section that is controlled by a numerical control device and causes an error due to temperature changes, the drive section includes a temperature sensor that detects temperature, and the numerical control device is controlled by a temperature change detected by the temperature sensor. A numerical control system characterized in that the system is configured to compensate the control of the drive unit in accordance with the above.