JPS60160399A - Controlling method of stepping motor - Google Patents

Abstract

PURPOSE:To improve the positining accuracy by controlling a linear pulse motor by using an information table for storing position information. CONSTITUTION:The moving amount is measured by a moving amount measuring unit 9 by cooperating with the moving operation of a linear pulse motor LPM having a pole teeth detector 7. Position information measured by the unit 9 is corresponded by a comparison correcting circuit 11 to the pole teeth position detected by the detector 7, and the corresponding position information is written in a ROM15 through a ROM writer 13. When controlling to position in an open loop with the ROM15, the ROM15 is corresponded to a correcting calculator 21, and the motor LPM is driven through a drive unit 23.

Description

[Detailed description of the invention] The present invention relates to a stepping motor control method.

Generally, a stepping motor has pole teeth, and positioning is controlled by detecting the position of the pole teeth using an optical or magnetic detection device. Therefore, the manufacturing accuracy of the pole teeth directly affects the positioning accuracy, and for this reason, attempts are being made to manufacture the pole teeth with high accuracy. However, as stepping motor technology has improved in recent years, on the one hand, the technology for subdividing the pole teeth, and on the other hand, the technology for stopping at the dividing position between the pole teeth has improved. That is, for example, in a linear stepping motor, the pole tooth big is 1+nn+ or less, and the split stop technology is 1/
This made it possible for the ball to be played at 4.1/8 pitch or higher. This means improved positioning resolution,
In the above example, C has a resolution of 1 mm x 1/8 = 0.125 mm.

Therefore, power collection and the above-mentioned accuracy in manufacturing the pole teeth become issues. That is, conventionally, for example, 0,
1 to Q, manufacturing errors of about 3 mm have been ignored, but these days, as resolution has improved, these values have become unacceptable. However, it is impossible to further improve the manufacturing accuracy, and it also affects the hair loss. Also, in the past, although it is possible to improve the accuracy of the pitch between each pole tooth,
It is almost impossible to manufacture all the pole teeth to a value required for positioning accuracy, for example, an accuracy of about 1/10 (about 0.01 mm) of the above-mentioned resolution.

In conventional stepping motors, despite the existence of resolution improvement technology, it is not possible to precisely control the positioning of each pole tooth from the origin position. It was.

In view of the above-mentioned prior art, an object of the present invention is to provide a control method that can improve the positioning accuracy of a stepping motor, and another object is to provide a stepping motor that can be controlled with high precision even in a closed loop. The objective is to provide a control method for

In order to achieve the above object, the present invention measures the amount of movement of the stepping motor in conjunction with the movement of the stepping motor equipped with a pole tooth detection device using a movement amount measuring device, and detects the amount of movement of the stepping motor by using the pole tooth detection device. There is a method for controlling a stepping motor characterized in that the stepping motor is controlled using an information table in which the position information measured by the displacement measuring device is associated with the position of the pole tooth and the position information is stored.

Hereinafter, the above invention will be described in detail with reference to examples.

FIG. 1 is a partially enlarged explanatory diagram of the linear stepping motor STM. Pole teeth 3a provided on the stator 1.

The pole tooth 3a is attached to the movable element 5 facing 3+1, 3C...
.

A pole tooth detection device 7 is provided to detect 3b, 3C, . . . .

The pole tooth detection device 7 is of an optical type, and uses, for example, an optical fiber to sequentially detect the shoulders of the pole teeth 3a and 3C to obtain a detection signal. As the pole tooth detection device, in addition to an optical sensor, a magnetic induction sensor, a Hall element hinge, etc. can be used. Incidentally, a plurality of pole tooth detection sensors may be provided as desired for direction determination, division stop, etc.

FIG. 2 shows an example of a method for creating an information table used in the present invention. In conjunction with the movement of the stepping motor STM equipped with the pole tooth detection device 7, the amount of movement of the stepping motor STM is measured by the amount measuring device 9. Then, C1 makes the positional information measured by the movement amount measuring device 7 correspond to the pole tooth position detected by the pole tooth detecting device 3-7, and the corresponding positional information is stored in the ROM 15 via the ROM writer 13. This is an example of writing to . Here, an example is shown in which the movement amount measuring device 9 is a sub-long device in which a reading head 19 is provided on a substrate 17 and the reading head is connected to the movable element 5. It is sufficient to be able to accurately measure the motion, and any method or format may be used, such as a general sub-length instrument, a calibrated Magnescale, a linear scale, an Inductosin, etc.

The comparison and correction circuit 11 in FIG. 2 uses detection information for position control conventionally used in stepping motors, that is, for example, multiplies the n-th signal by the pitch pfflIIl, and calculates the position as nxp mm. This is a circuit that corrects the information measured using actual measured values.

That is, the information table written in the ROM 15 indicates that the nth signal generation point is nxp mm and the correction value ΔAnon is
, or the [)th signal generation point is marked as a new value, nxp±Δαmm, etc. Here, multiple pole tooth detection devices are installed (
), and when a detection signal is generated for each pitch of 1/2.1/4.1/8° (hereinafter, this divided section is referred to as 1 step), each of these signals is It is also possible to make the measured values of the quantity measuring device correspond or to ignore the error between the pitches, for example, to obtain the position information of the division point by simple averaging.

The position information in the ROM 15 can be easily set to about 1/10 (about 0.01 mm) of the resolution of 0.125 m1 when the pole tooth pitch is 1 mm and the stop division position is 1/8 of that. . Therefore, for example, the position of each pole tooth from the origin in a linear stepping motor is o,
It can be positioned with an accuracy of ``oimm'' or better.

FIG. 3 shows an embodiment in which open-loop positioning control is performed using the ROM 15. A ROM 15 is associated with the correction calculation unit 21, and the stepping motor STM is driven via the drive unit 23. For example, conventionally, the resolution is 0.125 mm, and 10
When a movement command of 0 step, 0.125xl 0O=12.5m+n is given, the actual movement is 12.1m due to an error.
It is assumed that mb does not move and the stopping error is 0.4 mm. However, in this embodiment, the ROM shown in FIG.
15, for example, 12.511111
1 is determined to be 103 steps, for example 12.47
Stops at the 5mm position. Stops with an error of 0.025mm.
It is possible to do something. In this way, the stopping error with respect to the origin in this example is determined by the resolution (0.125 mm in this example).
) can be contained in the following. The same holds true even if the positioning operation is performed again from the stop position.

FIG. 4 shows an example of positioning control using a full closed loop. The command value is compared with the ROM 15 in the comparator circuit 25, and the stepping motor STM is driven via the drive circuit 27, and the moving amount of the stepping motor STM is determined by the detected amount of the pole tooth detecting device 7, for example, and the position data 29 It is returned to the comparison circuit 25 as In conventional feedback control using a stepping motor, there were problems with poor manufacturing precision of the pole teeth, but in this example, positioning can be performed with a stopping error within the resolution (for example, 0.125 mm), and , the value shown as this resolution can be made smaller and smaller.

As explained above, in this invention, it is possible to absorb positional errors due to the manufacturing accuracy of the pole teeth, especially the manufacturing accuracy of each pole tooth from the origin position, but it is possible to absorb positional errors due to the accuracy of manufacturing the pole teeth from the origin position. It is possible to absorb errors, distortion errors due to long-term use, and dimensional errors due to temperature differences, and it is possible to control the stepping motor with high precision.

As is clear from the above description, the stepping motor control method according to the present invention measures the amount of movement of the stepping motor with a movement amount measuring device in conjunction with the movement operation of the stepping motor equipped with a pole tooth detection device. , the position information measured by the moving device is made to correspond to the position of the pole tooth detected by the pole tooth detection device, and the stepping motor is controlled using an information team in which the position information is stored. Because of this feature, it is possible to control with high precision in an open loop or in a closed loop.

[Brief explanation of drawings]

The drawings all show examples, and FIG. 1 is a partially enlarged explanatory diagram of a linear stepping motor, FIG. 2 is a plan explanatory diagram for measuring the amount of movement of a linear stepping motor, and FIG.
The figure is a block diagram showing an open-loop positioning control method, and FIG. 4 is an explanatory diagram showing a closed-loop positioning control method. 1... Stators 3a, 3b, 3c... Pole teeth 5... Mover 7... Pole tooth detection device 9... Movement amount measuring device 15
...ROMSTM...Stepping motor agent Patent attorney Yasuo Miyoshi 8- Figure 2 Procedural official document (spontaneous) May 2, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1981 Patent Application No. 14299 2,
Title of the invention: Method for controlling a stepping motor 3, Representative of the person making the amendment: 1) Full amount 4, Agent 6, Contents of the amendment 2 - Specification 1, Name of the invention: Method for controlling a linear pulse motor 2, Claims A movement measurement device C measures the amount of movement of the linear pulse motor in conjunction with the movement of a linear pulse motor equipped with a pole tooth detection device, and measures the amount of movement at the pole tooth position detected by the pole tooth detection device. 1. A method for controlling a linear pulse motor, characterized in that the linear pulse motor is controlled by using an information table in which position information measured by a device is correlated and the position information is stored. 3. Detailed Description of the Invention The present invention relates to a method of controlling a linear pulse motor. Generally, a linear pulse motor is provided with pole teeth, and positioning is controlled by detecting the position of the pole teeth with an optical or magnetic detection device. Therefore, the manufacturing accuracy of the pole teeth directly affects the positioning accuracy, and for this reason, attempts are being made to manufacture the pole teeth with high accuracy. However, with recent improvements in linear pulse smoke technology, on the one hand, C is the subdivision of the pole teeth, and on the other hand, the stopping technology (at the dividing position between the pole teeth) has improved. In other words, for example, in a linear pulse motor, The pole tooth pitch is 111) Il) below, and the split stop technique is 1/
It has come to be played at 4.1/8 pitch or more. This means an improvement in positioning resolution, which in the above example is 1 mm x l/8 = 0.125 mm. Therefore, the above-mentioned accuracy in manufacturing the pole teeth becomes a problem. In other words, in the past, for example, manufacturing errors of about 0.1 to 0.3 mm in 2+111+1 pitch pole teeth tended to be ignored, but as resolution has improved these days, it has become a value that cannot be ignored. be. It is important to improve the manufacturing accuracy on the Jζ surface.
This makes sense, and also increases costs. In addition, although it is possible to further improve the accuracy of the bits between each pole tooth in the conventional C, it is possible to improve the precision of the bits between each pole tooth, but it is not possible to increase the precision of positioning all the pole teeth from the origin position, for example, by 1/1/2 of the above-mentioned resolution.
It is almost impossible to manufacture it with an accuracy of about 10 (about 0.01 mm once). In conventional linear pulse motors, despite the existence of resolution improvement technology, it was not possible to precisely manufacture the position of each pole tooth from the origin position, and it was not possible to perform positioning control with high precision. It is. In view of the above-mentioned prior art, it is an object of the present invention to provide a control method that can improve the positioning accuracy of a linear pulse motor. An object of the present invention is to provide a method for controlling a pulse motor. In order to achieve the above object, the present invention measures the amount of movement of the linear pulse motor with a movement amount measuring device in conjunction with the movement of the linear pulse motor equipped with a pole tooth detection device, and measures the amount of movement of the linear pulse motor with a movement amount measuring device. A linear pulse motor characterized in that the detected pole tooth position is associated with position information measured by the movement amount measuring device, and the control of the linear pulse motor is performed using an information table in which the position information is stored. This is a control method. Hereinafter, the above invention will be described in detail with reference to examples. FIG. 1 is a partially enlarged explanatory diagram of the linear pulse motor Ll)M. Poles m3a, 3b provided on stator 1. The pole teeth 3a, 3 are attached to the movable element 5 facing 3C...
b. A pole tooth detection device 7 is provided for detecting 3G... sequentially detect,
Detection signal is obtained. As the pole tooth detection device, in addition to an optical sensor, a magnetic induction sensor, a ball element sensor, etc. can be used. Incidentally, a plurality of pole tooth detection sensors may be provided as appropriate for determining directionality, dividing and stopping, etc., as desired. FIG. 2 shows an example of a method for creating an information table used in the present invention. The displacement of the linear pulse motor LPM is measured by the displacement measurement device 9 in conjunction with the movement of the linear pulse motor LPM equipped with the detection device 7. Then, the comparison correction circuit 11 makes the position information measured by the movement amount measuring device 7 correspond to the pole tooth position detected by the pole tooth detection device 7, and the corresponding position information is stored in the ROM writer 1.
This is an example of writing to the CROM 15 via 3. Here, an example of a sub-length device is shown in which the movement amount measuring device 9 is equipped with a reading head 19 on a substrate 17 and the reading head is connected to the movable element 5, but in short, it is a linear pulse motor LPM.
It is sufficient to accurately measure the movement of the movable element 5, using a so-called general length measuring device, a calibrated Magnescale,
Any method such as linear scale, inductosyn, etc.
It may be in any format. The comparison and correction circuit 11 shown in FIG. 2 uses detection information for position control conventionally used in linear pulse motors, that is, for example, the first signal is multiplied by the pitch p1m, and the position is determined by multiplying the first signal by the pitch p1m. This is a circuit that corrects and sets the information that p III m 'r exists using the actual measured value. In other words,
In the information table written in the ROM 15, the n-th signal generation point is n X p m III and the correction value Δ magazine m
m, or the first signal generation point is to the new square, nxp±8αm, and so on. Here, a plurality of pole tooth detection devices are installed, and detect signals at every pitch of 1/2.1/4.1/8° (hereinafter, this divided section is referred to as 1 step). If such signals are generated, it is possible to correspond to the measured values of the movement measuring device, respectively, or to ignore the error between the pitches and use simple averaging to obtain the position information of the divided point. The position information stored in the ROM 15 is approximately 1/10 of the resolution of 0.125 mm (0.01 m) when the pole tooth pitch is 1 mtn and the division stop position is 1/8 of that
m) can be easily set. Therefore, for example, if the origin of C1 is set to a linear pulse motor, each pole tooth position of the motor is set to 0.
．． It is possible to position with an accuracy of 0.01 m... or more. FIG. 3 shows an embodiment in which the ROM 15 is used for open Luso positioning control. A ROM 15 is associated with the correction performance section 21, and the linear pulse motor LPM is driven via the drive section 25-3. For example, conventionally, assuming a resolution of 0.125n+n+, 100 steps, 0.125X 10
0 = When a movement command of 12.5mm is given, the actual movement is 12.1mmL due to an error, and the stopping error is Q.
, 4 mnVc. However, in this embodiment, the ROM 15 shown in FIG.
For example, 12.5ml1 is determined to be 103 steps, and a stopping error of 0.
025ml1llr". In this way, the stopping error based on the origin can be kept below the resolution (0.125mm in this example). The same holds true even if the positioning operation is performed again from the stopped position. An example of positioning control using a full closed loop is shown in Fig. 4.The command value is compared with the comparison circuit 25 F R0M15, and the linear pulse motor LPM
The amount of movement of the linear pulse motor LPM is determined, for example, by the amount detected by the pole tooth detection device 7, and position data 2 is obtained.
Return to the comparison circuit 6-25 as 9.16 In conventional feedback control using a linear pulse motor, the manufacturing accuracy of the pole teeth has always been a problem, but in this example, the resolution (for example, 0.12
Positioning is possible with a stopping error within the range of 5n+m>, and furthermore,
The value shown as this resolution can be made smaller and smaller depending on future resolution improvement technology. As explained above, in this invention, it is possible to absorb positional errors due to the manufacturing accuracy of the pole teeth, especially the manufacturing accuracy of each pole tooth from the origin position, but it is also possible to absorb positional errors due to equipment installation errors and external forces. It is possible to absorb both errors, positive errors due to long-term use, and dimensional errors due to temperature differences. As is clear from the above description, the method for controlling a linear pulse motor according to the present invention involves measuring the amount of movement of the linear pulse motor in conjunction with the movement of the linear pulse motor equipped with a pole tooth detection device. , the position information measured by the movement amount measuring device is made to correspond to the pole tooth position detected by the pole tooth detection device, and the information table in which the position information is stored is used to control the linear pulse motor C. Since it is characterized by covering the area, it is possible to make the crane 117 with high accuracy in an open loop or a closed loop. 4. Brief explanation of the drawings The drawings all show examples. Fig. 1 is a partially enlarged explanatory view of a linear pulse motor, Fig. 2 is a plan explanatory view when measuring the amount of movement of a linear pulse motor, and Fig. 3 The figure is a block diagram showing an open-loop positioning control method, and FIG. 4 is an explanatory diagram C showing a closed-loop positioning control method. 1... Stators 3a, 3b, 3c -... Pole teeth 5... Mover 7... Pole tooth detection device 9... Movement amount measuring device 15
...ROMLPM...Linear pulse motor representative Patent attorney Tamotsu Miyoshi 9-

Claims (1)

[Claims] A movement measurement device measures the amount of movement of the stepping motor in conjunction with the movement of a stepping motor equipped with a pole tooth detection device, and the movement amount measurement device measures the amount of movement of the stepping motor at the position of the pole tooth detected by the pole tooth detection device. A method for controlling a stepping motor, characterized in that the stepping motor is controlled using an information table in which position information is associated and the position information is stored.