JPS6235920A - Positioning control system - Google Patents

Abstract

PURPOSE:To always accurately position a linearly moving body even in case of the step-out phenomenon of a pulse motor occurs by detecting the extent of movement of the linearly moving body, for example, an X-Y table by a sensor and feeding back this extent of movement to compensate positioning. CONSTITUTION:Assuming that a designated movement extent (x) includes a maximum of a distance NX0.5l, a CPU 8 outputs MXN-number of pulses to a pulse motor 6 through a motor controller 7 for the purpose of moving an X-Y table 1 for the distance NX0.5l. Then, the X-Y table 1 is advanced from the initial position, and optical fiber type photoelectric switches 3 and 4 generate pulses each time when light is projected and received from a reflecting face 2c by movement of the X-Y table 1, and a counter 5 counts these pulses. Thereafter, a counted value C of the counter 5 is fetched, and it is judged whether this value C is equal to N or not. If the value C is equal to N, this state indicates that the X-Y table 1 is not advanced for the designated distance (x), and therefore, the remainder distance is operated, and the number of pulses to be supplied to the pulse motor which corresponds to this operated distance is operated, and pulses are supplied to the pulse motor 6 through the controller 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positioning control system for positioning a linearly moving body, such as an X-Y table.

[Conventional technology]

Conventional positioning control systems for linear moving bodies, such as X-Y tables, use pulse motors as drive sources.
There is a pulse motor type positioning control system that executes positioning without feedback of the amount by which the linearly moving body moves due to the drive of the pulse motor. Another positioning control method is to install a rotary encoder on the shaft of the drive transmission mechanism to transmit the driving force of the servo motor to the x-y table, and control the servo motor by feeding back the count value from this encoder. There is a feedback type positioning control system that performs positioning using

[Problem that the invention seeks to solve]

However, in the above-mentioned pulse motor type position method control system, even if a predetermined pulse is sent to the pulse motor, the pulse motor does not rotate the predetermined number of rotations, resulting in so-called step-out development, and the X-Y table etc. does not move in the predetermined direction. There is a problem in that the position is determined without moving a predetermined distance.

In addition, in the feedback type positioning control method, the rotation of the axis is detected with an encoder and fed back as the amount of movement.\\The final positioning is performed by directly detecting the amount of movement of a linearly moving object such as an X-Y table. This invention was made to solve the above-mentioned problems, and aims to always accurately position a linearly moving object with a simple configuration. The purpose is to obtain a positioning control method that allows for

[Summary of the invention]

In order to achieve the above object, the present invention provides a positioning control system in which a linear moving body capable of linearly reciprocating motion is driven by a drive means to perform positioning, and in which Detection sections are provided integrally with the linearly moving body at equal intervals along the line, and detection means is provided for outputting a detection signal every time the detected section moves by a predetermined width. The detecting means detects the maximum number of the predetermined widths that the specified movement amount includes, and detects that the i-line moving body has moved by a coarse control width that is the detected number of predetermined widths. The drive means is driven to move the linearly moving body until detection is detected based on the detection signal from the drive means, and a drive signal corresponding to the remaining movement amount obtained by subtracting the rough control width from the specified movement amount and the specified movement amount. By applying the force to the driving means, the linearly moving body is further moved by the remaining movement amount to perform positioning.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 and FIG. 3 show an embodiment of the movement amount detecting section of the present invention.
- The Y table 1 is assumed to reciprocate one-dimensionally in the direction of the arrow shown in the figure, for example, in the X direction, and along the
A mechanical scale 2 for detecting the amount of movement is provided on the side surface of the table 1. The mechanical scale 2 has a groove 2a and a protruding detection part 2b between the grooves 2a, and one groove 2a and one detection part 2b make one pitch! The groove portions 2a and the detection portions 2b are regularly arranged alternately in the X direction at a pitch of 1. The groove portion 2a is painted black with paint or the like so as not to reflect light, and the reflective surface 2C of the detection portion 2b is mirror-shaped so as to totally reflect light. This mirror shape can be achieved by polishing the reflective surface 2c, for example, if the material of the mechanical scale 2 itself is made of a light-reflective metal; If the reflective surface 2c is made of a material that does not have a reflective surface, it can be realized by plating the reflective surface 2c. Reference numerals 3 and 4 are optical fiber type photoelectric switches having the function of a reflective photocoupler that transmits and receives light to and from the mechanical scale 2 using concentric optical fibers, and the detection positions on the mechanical scale 2 are half-way from each other. Pituchi (
The optical fiber type photoelectric switches 3° 4 are arranged so as to be shifted by 0, 5, , e).

FIG. 4 shows the circuit configuration of the present invention. In the figure, 5 is a counter that counts the pulses output by the optical fiber type photoelectric switches 3 and 4. Reference numeral 6 represents a driving pulse motor that moves the above-mentioned X-Y table 1 in, for example, the X direction via a mechanism not shown, and 7 represents a motor controller that fully controls the amount of rotation of the pulse motor 6. Reference numeral 8 denotes a well-known central processing unit (hereinafter referred to as CPU), which inputs commands and data from the input device 9, takes in and calculates the count value of the counter 5, and controls the pulse motor via the motor controller 7. Controls the rotation of 6.

FIG. 5 shows an embodiment in which the inside of the CPU 8 shown in FIG. 4 is broken down by function. In the figure, 8a is a memory means for storing data necessary for calculations, etc., and 8b is a memory means for storing data from outside. It is a memory control means that inputs data and stores and reads data in the memory means 8a. 8c is a first calculation means that performs a first calculation based on the data for the first calculation given from the memory control means 8b; 8d is a first calculation means that compares the calculation result by the first calculation means 8c with a predetermined input value. This is the first comparison and determination means that makes a determination based on the results. Reference numeral 8e denotes a second arithmetic means that performs a second arithmetic operation based on data for the second arithmetic operation provided from the memory control means 8b. 8f is a second comparison/judgment means that compares and makes a decision based on comparison data given from the memory control means 8b; 8g is a third calculation based on the comparison result of the second comparison/judgment means 8f; This is the third calculation means that performs. 8h is an output means, which outputs the calculation results of the second calculation means 8e and the third calculation means 8g as pulses for controlling the pulse motor 6.

FIG. 1 is a flowchart showing the operation flow of the CPU shown in FIG.

Next, the operation of one embodiment of the present invention will be explained.

First, it is assumed that the X-Y table 1 has returned to its initial position in the X direction. It is periodically determined whether the specified moving distance
o If it is determined that there is an input of movement distance X, initialize by setting n equal to 1 (step S2).

Next, 0. Perform the calculation of fMtlXn (step 83
), it is determined whether the calculation result 0.5-e*n is greater than the input specified movement distance X (step 84
).

If 0.51・n>x does not hold, add 1 to n and update it as a new n (step S5), then step S again.
Repeat the operation from 3. The above operation is repeated until 0.5-e@n>X is established. The above operation searches for the maximum extent to which the specified moving silver Iftx includes the detection resolution of the optical fiber photoelectric switches 3 and 4 for the mechanical scale 2, that is, the half pitch of the mechanical scale 2 of 0.51 minutes. .

If an affirmative determination is made in step S4, 0. un>x holds, and in this case, the specified moving distance X is at most N=n
-1 half pitch 0.5 # distance. Therefore, N-=n-1 is calculated and stored in memory (step 86).

Assume that when the CPU 8 gives M pulses to the pulse motor 6 via the motor controller 7, the X-Y table 1 moves in the X direction by a distance of 0.5 half pitches. In order to move the X-Y table 1 by a distance of Nx0.5J, calculate MXN.Step 87
), MXN pulses are output to the pulse motor 6 via the motor controller 7 (step S8). As a result, the X-Y table 1 moves forward from the initial position, and this
By moving the Y table 1, the optical fiber dimmer electric switch 3.4 generates a pulse every time light is emitted or received from the reflecting surface 2C, and the counter 5 counts this pulse. In addition, here, every time the X-Y table 1 moves by half pitch 0.51, one signal is sent from either the optical fiber type photoelectric switch 3 or 4.
One pulse is output.

As mentioned above, the X-Y table 1 has N half pitches of 0.
When the object moves by a distance of 5f, the count value C of the counter 5 should be equal to N. In step S8,
After outputting MXN pulses and moving the X-Y table 1 forward in the X direction, the count value C of the counter 5 is taken in (
Step S9), it is determined whether it is equal to the count value CtiN (step 510).

If a negative determination is made in step S10, there is some cause of failure or out-of-step development and N is not equal to C, so a lamp (not shown) is lit to indicate out-of-V@development or failure. A control signal for this purpose is output (step 513).

In step S10, if an affirmative determination is made, X-
Since the Y table 1 has not moved forward by the specified moving distance X, the remaining distance is calculated and the number of pulses to be applied to the pulse motor 6 corresponding to the distance is calculated. Here, x
-0,513.NId, X - This is the remaining moving distance that the Y table must move, and the number of pulses given to the pulse motor 6 corresponding to this remaining 9i distance is 2.

(1) calculation is performed (step 811), and pulses for Z are sent to the pulse motor 6 via the motor controller 7.
(step 512), the X-Y table 1 moves forward in the X direction by the remaining distance x -0,5-e exposure N, and in total moves forward by the distance Mx in the X direction from the initial position. It turns out. This completes a series of X-Y table movement operations in the X direction, and positioning control is performed.

FIG. 6 shows another embodiment of Jin's invention, and the CP of FIG.
It is a flowchart of the operation|movement which U8 performs.

In FIG. 6, steps 81 to slo are the same, but the next step when a negative determination is made in step 810 is different from the above embodiment.

Other operations and configurations are the same as in the above embodiment.

If a negative judgment is made in step SIO,
It is assumed that the number of pulses applied to the pulse motor 6 is insufficient due to tax adjustment development, etc., and a predetermined number of pulses are output to the pulse motor 6 via the motor controller 7 (step 514). Each time the x-y table 1 is moved by a short predetermined distance by applying this predetermined number of pulses, the counter 5
The count value C is read and it is determined whether it is equal to N (step 515). If a negative determination is made in step 815, the process returns to step 81.4 and repeats the above-described operation until C=N.

If an affirmative determination is made in step 815, the process moves to step Sll. Further, if an affirmative determination is made in step 810, the process also moves to step S11.

The steps following step 811 are exactly the same as the operations described in FIG. 1, so their explanation will be omitted.

FIG. 7 shows another embodiment of the movement amount detecting section of the present invention, in which a pair of the above-mentioned mechanical scales 2 are arranged in correspondence with each other along the movement direction on both sides of the x-y table 10. An optical fiber type photoelectric switch 3 is placed on one side of the mechanical scale 2, and another optical fiber type photoelectric switch 4 is placed on the other side of the mechanical scale 2. The relative phase shift between the detection positions of the optical fiber type photoelectric switches 3 and 4 is a half pitch of 0.51, that is, 180 degrees. This has the advantage of making it easy to arrange the optical fiber type photoelectric switch 3.4, and also makes it possible to narrow the width of the mechanical scale 2 in the longitudinal direction and the perpendicular direction.
It becomes easy to manufacture.

In each of the above embodiments, the detection positions of the pair of optical fiber type photoelectric switches are explained as positions on the mechanical scale shifted by half a pitch, but the phase is 1800, that is, the position on the mechanical scale detected by one optical fiber type photoelectric switch. Of course, the detection position on the mechanical scale, which is an integer pitch plus a half pitch, may be used as the detection position detected by another optical/fiber type/photoelectric switch.

In each of the above embodiments, a mechanical scale with closing grooves was used, but this is not just a scale, but one in which reflective surfaces are regularly arranged on a flat surface in the shape of a scale. Of course, this is a good thing.

Furthermore, in each of the above embodiments, two optical fiber type photoelectric switches are used, but by using three or more, it is possible to achieve even higher resolution by shifting the phase of the detection position of the mechanical scale. Further, in each of the above embodiments, light is used for detection, but it goes without saying that other sensors such as a proximity switch, a capacitive displacement switch, etc. may be used for detection.

〔Effect of the invention〕

As explained above, according to the present invention, even if the pulse motor causes tax adjustment, the sensor detects the amount of movement of a linearly moving object, such as an X-Y table, and feeds it back to correct the position method. This allows for accurate positioning at all times.Moreover, coarse feedback movement control is performed in units of sensor resolution, and open-loose control is used for movement control finer than the sensor resolution. This has the effect of simplifying the configuration.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of a CPU showing an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing an embodiment of the position detection mechanism portion of the present invention, and FIG. 4 is a diagram showing a circuit configuration of the present invention. FIG. M5 is a block diagram of an embodiment showing the contents of the CPU shown in FIG. 4. FIG. M6 is a partial flow chart of the CPU showing another embodiment of the present invention.
The figure is a perspective view showing another embodiment of the position detection mechanism portion of the present invention. In the figure, 1 is an X-Y table, 2 is a mechanical scale,
2c is a reflective surface, 3.4 is an optical fiber type photoelectric switch, 5
is kakunta, 6 is pulse motor, 7 is motor control) o-
8 is the CPU, 9 is the input device. In addition, in the figures, the same reference numerals indicate the same parts or the monk parts. Fig. 2 S Fig. □ Fig. 5 Me7'18 80 8b 8c 8d ℃ temperature car → Meiyari Soil 1
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Claims (2)

[Claims] (1) In a positioning control method in which positioning is performed by driving a linearly moving body capable of linearly reciprocating motion using a drive means, the detected portion is moved in the linear motion at equal intervals along the linear motion direction of the linearly moving body. A detecting means is provided integrally with the body and outputs a detection signal every time the detected part moves by a predetermined width, and detects the maximum specified movement amount of the linearly moving body inputted from the outside. Detect whether the specified width is included,
The driving means is driven to move the linearly moving body until it is detected based on the detection signal from the detecting means that the linearly moving body has moved by a rough control width that is the predetermined width corresponding to the detected number. After this movement, a drive signal corresponding to the remaining movement amount obtained by subtracting the rough control width from the designated movement amount is given to the driving means to further move the linearly moving body by the remaining movement amount to perform positioning. A positioning control method characterized by: (2) There is a plurality of the detection means, and the plurality of detection positions by the detection means have phases different from each other with respect to the phase depending on the position of the detected part. positioning control method.