JPH03250308A - Position corrector utilizing acceleration - Google Patents

Abstract

PURPOSE:To obtain a highly accurate position command by applying an acceleration component to a position feedback loop and correcting a mechanical displacement component via a position control system. CONSTITUTION:The position command inputs are added together via two differentiators 6 and 7 and a count setter and connected to a point 9. The acceleration is added to the position feedback value obtained by a position detector 5 and outputted to a position digitization data producer 10. Therefore an acceleration component is applied to the position feedback loop when the acceleration is produced. Thus a mechanical displacement component caused by the acceleration can be compensated by a position control system. In such a constitution, the highly accurate position commands are obtained for production of the digitization data and the NC working.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an NC copying machine or a copying digitizer, and relates to an acceleration position correction device for correcting mechanical displacement due to acceleration.

<Prior art> Figure 3 shows a copying digitizer as an example;
An example of creating machining data by copying a model shape using position commands is shown.

In Figure 3, the position command input PCM0 is the addition point 1.
The feedback amount P is added to 8, and the speed command V is obtained by multiplying by the coefficient Kp. M.

(KP(PoM.-P,.)) is obtained. Furthermore, the speed command vc0° is added to the feedback amount vFa at addition point 2, and multiplied by the coefficient Kv to obtain the torque command TC, which is the current value.
Obtain MO(KV (“CMI) −vFIL )).

The motor 3 is driven by this torque command, the copying device 4 copies the model shape, and the position detector 5 obtains machine position digitized data.

<Problems to be Solved by the Invention> However, when copying a model based on a position command, there is a problem that the mechanical position of the copying device deviates from the position command.

That is, when an acceleration occurs in the copying device 4 due to the operation of the motor 3, a mechanical displacement always occurs compared to the acceleration. Moreover, in recent high-speed scanning, the acceleration increases in accordance with the speed, and the mechanical displacement cannot be ignored.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an acceleration position correction device that corrects a machine position using acceleration motion.

Means for Solving the Problems> The present invention achieves the above object by differentiating the position command twice in a 1g system that drives a motor via a position control loop and a speed 111II11 loop based on a position command. The acceleration obtained by or by the acceleration sensor is
It is characterized by being added to the feedback loop of the position control loop.

Function> When acceleration occurs, the acceleration variation is added to the position feedback loop, and the mechanical displacement due to acceleration can be corrected by the position control system, allowing high precision when creating digitized data and NC processing. Position command can be obtained.

Example> The present invention will now be described in detail with reference to FIGS. 1 and 2. Note that FIG. 1 shows a digitizer, and FIG. 2 shows a copying NC processing machine. The same parts as in FIG. 3 are given the same reference numerals.

In Figure 1, 1 and 2 are addition points, 3 is a motor, and 4 is a
5 is a copying device, and 5 is a position detector.

Furthermore, in FIG. 1, the position command input is performed twice by the differentiators 6 and 7.
and is connected to the summing point 9 via the coefficient setting N8.

Then, at this addition point 9, the acceleration from the differentiators 6 and 7 and the coefficient setter 8 is added to the position feedback amount from the position detection M5, and the result is output to the position digitization data generator ulO.

In such a configuration, the acceleration obtained by differentiating the position command by 2@ and multiplying by a coefficient 4 is added to the position feedback amount, and the actual position of the machine is determined by the displacement amount that takes into account the mechanical displacement of the copying device 4 due to the acceleration. Can be corrected. Therefore, there is no error in the position of the actual contact point of the machine with respect to the position feedback amount, and it is possible to match the position.

FIG. 2 shows an example of application of a copying NC processing machine.

In this control of the processing machine 11, the output of the position detector 5 is added with the acceleration based on the two-time differential @6, 7 and the coefficient setting M8 at the addition point 12 to obtain the position feedback amount.

Even in the example shown in FIG. 2, displacement due to acceleration of the processing machine 11 can be corrected by position feedback control.

In the embodiments shown in FIGS. 1 and 2, the acceleration is obtained by second differentiation, but an acceleration sensor may be attached to obtain the acceleration directly.

Furthermore, although the example in FIG. 1 describes a digitizer, it can also be applied to a three-dimensional measuring machine.

Furthermore, the example shown in FIG. 2 is applicable not only to a copying NC machine but also to other NC machines, copying machines, robots, and the like.

<Effects of the Invention> As explained above, by adding the acceleration variation to the position field pack loop and correcting the mechanical displacement in the position control system, a highly accurate position command can be obtained.

[Brief explanation of drawings]

1 and 2 are control block diagrams of two embodiments of the present invention, and FIG. 3 is a control block diagram of a conventional example. In the figure, 6.7 is a differentiator, 1.2 and 9.12 are addition points, and 10 is a position digitization data creation bar.

Claims (1)

[Claims] In a control system that drives a motor via a position control loop and a speed control loop based on a position command, the acceleration obtained by differentiating the position command twice or by an acceleration sensor is used in the position control loop. An acceleration position correction device characterized by being added to a feedback loop.