JPH02226311A - Positioning control method for general motor - Google Patents

Abstract

PURPOSE:To easily stop a control object in an allowable range to reduce the number of times of retry operation by setting a final target value to the middle of the allowable range for the target value. CONSTITUTION:Positioning data and function data are inputted from a keyboard 10 to a controller 12. A CPU of the controller 12 adds a 1/2 of the value, which is obtained by subtracting the negative-direction allowable range from the positive-direction allowable range, to the target value and sets the result to a pulse counter 14 as the final target value. The controller 12 starts an AC induction motor 16 to rotate a feed shaft 18 by driving of the motor 16, and the extent of movement of a control object 20 is converted to a pulse signal by a pulse encoder 22 and is fed back to the pulse counter 14. The controller 12 discriminates whether the control object 20 reaches the stop range or not in accordance with the counter value of the pulse counter 14. Thus, the precision of the actual stop position to the target value is improved, and it is unnecessary to repeat the retry operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positioning control method using a general-purpose motor such as an AC induction motor.

[Conventional technology]

Generally, in a positioning device using a high-precision motor such as a stepping motor or a servo motor, a controlled object is accurately positioned at a target value. However, such high precision motors are expensive.

When positioning a controlled object using an inexpensive general-purpose reduction motor, the accuracy of the actual stop position relative to the target value is not good. In particular, as shown in Figure 4, when the positioning OK range is biased toward the positive side with respect to the target value, the motor attempts to stop the controlled object by aiming at the target value through retry operation, but the accuracy Since the positioning is not good, it is difficult to reach the OK positioning range (tolerable range), and the positioning trial operation is repeated many times. The same applies when the positioning OK range is biased toward the negative side with respect to the target value.

The present invention aims to eliminate the above-mentioned defects.

[Problem that the invention seeks to solve]

In order to achieve the above object, the present invention provides a method for controlling the movement of a controlled object by rotating a general-purpose motor and stopping the controlled object at a position that substantially matches a target value. The subtracted value 172 is added to the target value, this value is set as the final target value, and the general-purpose motor is controlled based on this final target value.

〔Example〕

The configuration of the present invention will be described below with reference to the flowcharts shown in the accompanying drawings.

First, positioning data and function data are input from the keyboard 10 to the controller 12. Assume that the process 1 is 100 strokes, the process 2 is 200 m, and as function data, the ten-direction positioning OK range is 0.2nwn, and the one-direction positioning OK range is 0.2■.

When positioning of process 1 starts (block 1),
The CPU of the controller calculates the final target value (block 2).

As shown in FIG. 2, normally the center of the positioning OK range and the target value are the same as shown in A, and the actual stopping position for positioning is also the same.

In this case, a disadvantage in positioning dimensions is that there is a strong possibility that the machined member will vary in plus or minus dimensions beyond the target value. However, depending on the machine, it may be more convenient to always position the object beyond the target value, such as with the mouth. That is, there are cases where it is desired that the cut member has a slightly positive angle. Conversely, there are cases where it is necessary to stop before the target value, as shown in (c).

That is, when it is desired that the cut member has a slightly negative score. Therefore, it is desirable to control the final stop target value to be at the center of the width set in the positioning OK range.Therefore, the controller calculates the final target value as follows.

In addition, in FIG. 2, the positioning direction is from left to right.

Target value + [(+direction positioning OK range) - (unidirectional positioning OK range)) / 2 = final stop target position The final target value calculated by the above formula is 100 + in the case of A above.
For m+ and mouth, the one-direction positioning OK range is set to zero, so 100.1mm, and for c, ten-direction positioning is OK.
Since the range is set to zero, it is 99.9nwn. The operator selects the desired one from A, 口, and E. The final target value is set in the pulse counter 14 of the controller 12. Next, the controller 12 outputs a normal rotation output ON signal to the AC induction motor 16, and the motor 1
6 (block 3). The feed shaft 18 is rotated by the drive of the motor 16, and the controlled object 20 moves in a linear direction.The amount of movement of this controlled object 20 is determined by the pulse encoder 2.
2 is converted into a pulse signal by the pulse counter 14.
will be given feedback. Next, the controller 12 determines from the count value of the pulse counter 14 whether the controlled object 20 has reached the stop range. This stop range is obtained by subtracting the overrun dimension from the final target value, and the overrun dimension refers to the coasting distance of the controlled object 20 after turning off the motor 16. If Yes, the controller 12 The forward rotation output to the motor 16 is turned off, and the stoppage of the motor 16 is confirmed (block 5). Next, the controller 12 determines whether or not the controlled object 20 is within the positioning OK range (block 6), and if No, moves to a repositioning operation (block 9). This repositioning operation is an operation in which when the controlled object 20 deviates from the positioning OK range, it is returned to three times the overrun dimension and then positioned again in the normal rotation direction.

If Yes is determined in the determination block 6, the positioning of the step 1 is completed (block 7), and the controller 12 completes the positioning of the step 2.
The positioning operation starts.

〔effect〕

As described above, the present invention has the effect that the final target value is set in the middle of the allowable range for the target value, and as a result, it is easier to stop the controlled object within the allowable range, and the number of retry operations is therefore reduced.

[Brief explanation of the drawing]

FIG. 1 is a flow chart 1 to FIG. 2 is an explanatory diagram, FIG. 3 is a block explanatory diagram, and FIG. 4 is an explanatory diagram of a conventional technique.

Claims (1)

[Claims] (1) Controlling the movement of the controlled object by rotating a general-purpose motor,
In the method of stopping the controlled object at a position that substantially matches the target value, 1/2 of the value obtained by subtracting the negative direction tolerance range from the positive direction tolerance range is added to the target value, this value is taken as the final target value, and this value is set as the final target value. A positioning control method for a general-purpose motor, characterized in that the general-purpose motor is controlled based on a final target value.