JPH1131013A - Positioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize the space-saving, inexpensive positioning method which has superior environmental resistance (wide specification temperature range) without contacting. SOLUTION: Pulses outputted by a pulse output means 8a in a control part 8 are supplied to a pulse motor 4 to move a movable part 5 by the rotation of a screw 3, and a pulse counter 8b in the control part 8 counts the pulses. Changes of the ON/OFF state of a Hall element 7 are monitored by a monitor means 8c in the control part 8, an arithmetic means 8d in the control part 8 finds the measurement relation value between the number of the pulses and the movement distance of the movable part 5 on the basis of the monitor result and the count result of the pulse counter 8b, finds the quantity of deviation of the relation value from a corresponding logical relation value as a correction value, and stores it in a storage means 8e. Then pulses whose number is determined in consideration of the corrected value are supplied from the pulse output means 8a to the pulse motor 4 to move the movable part 5 to a specific position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device having a position detecting mechanism using a Hall element for converting the intensity of a magnetic field into an on / off electric signal, and is disposed so as to be movable in parallel with respect to a fixed portion. The present invention relates to a positioning method for positioning and stopping a movable part at a predetermined position.

[0002]

2. Description of the Related Art In a mounter for mounting a semiconductor chip or the like, or a plotter (plotting device), for example, a pulse motor or the like is used to move a movable portion along a fixed axis by a distance corresponding to the number of applied pulses. It is configured to move. As a method for positioning a mounter or the like having such a pulse motor or the like, conventionally, for example, the following (1)
To (4). (1) A plurality of sensors such as a microswitch that mechanically detects the position of a movable part and a photosensor that detects light are installed at the end of each axis. Then, the position where each sensor is turned on / off is defined as a mechanical origin, and the moving distance is calculated from the number of pulses transmitted to the pulse motor from that position, and the position of the movable part is relatively determined. (2) A linear scale such as a magnet scale is installed on each axis, and the absolute position of the movable part is determined based on the read value. (3) A recognition mark is arranged on the movable part, and the movable part is positioned by image recognition using an industrial television camera (ITV camera) or the like. (4) A measurement target is placed on the movable part, and the movable part is positioned based on the distance directly measured using a laser sensor or the like.

[0003]

The method of the above (1) is as follows.
Although it can be generally realized at low cost, it is difficult to reduce the size of the positioning device, for example, by disposing the position detection mechanism outside the movable range. Further, in the methods (2), (3) and (4), the sensor used is expensive, and is used when particularly high accuracy is required. It is difficult to reduce the size of the positioning device, for example, by disposing the position detection mechanism outside the movable range. Therefore, in any of the above methods (1) to (4),
It has been difficult to obtain a positioning method that can realize accurate positioning even for a device having a small moving stroke. An object of the present invention is to solve the problems of the prior art, and to provide a positioning method that can be applied to a small-sized device with a small moving stroke and that can perform accurate positioning.

[0004]

In order to solve the above-mentioned problems, according to the present invention, there is provided a fixed part extending in a fixed direction, a movable part arranged to be movable in parallel with the fixed part, and A magnetic generation unit attached to one of the movable unit and the fixed unit, which generates magnetism of a predetermined magnetic field strength, in a direction corresponding to the polarity of a given pulse, and by a distance corresponding to the number of pulses, A moving unit for moving the movable unit in parallel with the fixed unit; and a moving unit attached to one of the fixed unit and the movable unit to turn on / off the magnetic field intensity when passing near the magnetism generating unit. A Hall element that converts the signal into an OFF electric signal and outputs the signal, a pulse output unit that outputs the pulse to be supplied to the moving unit, a counting unit that counts the number of output pulses, and an ON / OFF state of the Hall element. Strange Monitoring means, calculating means for monitoring,
And a control unit having a storage unit, the movable unit is positioned as follows using a positioning device. That is, the pulse output from the pulse output unit is supplied to the moving unit to move the movable unit, and the number of the pulses is counted by the counting unit, and the counting result of the counting unit and the monitoring of the monitoring unit are performed. On the basis of the result, the calculating means obtains an actually measured relation value between the number of pulses and the moving distance of the movable part, and obtains a deviation amount between this relation value and a corresponding theoretical relation value as a correction value. The number of pulses in consideration of the correction value is given to the moving unit to move the movable unit to a predetermined position. By adopting such a configuration, the pulse output from the pulse output means is given to the moving means to move the fixed part, the number of the pulses is counted by the counting means, and the monitoring means turns on / off the Hall element. The change of the state is monitored, and the relational value of the actual measurement between the number of pulses and the moving distance of the movable part is obtained by the calculating means. The amount of deviation between this relational value and the corresponding theoretical relational value is stored in the storage means as a correction value. Then, the number of pulses in consideration of the correction value stored in the storage unit is output from the pulse output unit, and is provided to the moving unit, so that the movable unit moves to a predetermined position. Thereby, the movable portion is accurately positioned at a predetermined position.

[0005]

FIG. 1 is a schematic structural view of a positioning device using a Hall element used in an embodiment of the present invention. This positioning device is provided in a device having, for example, one axis that moves linearly, such as a mounter or a plotter, and has a predetermined portion on a fixed portion (for example, a base) 1 extending in a certain direction. Two support parts 2a and 2b are fixed at a distance. A screw 3 disposed in parallel with the base 1 is rotatably mounted between the support portions 2a and 2b, and the screw 3 is connected to a pulse motor 4 mounted on one of the support portions 2a. In addition, a movable portion 5 that can move is attached to the screw 3. The pulse motor 4 has a function of rotating the screw 3 in a direction corresponding to the polarity of the given pulse and for a distance corresponding to the number of pulses to move the movable unit 5 in the left-right direction. The screw 3 and the pulse motor 4 constitute moving means for moving the movable part 5.

The movable portion 5 incorporates a magnetism generating portion (for example, a magnet such as a permanent magnet or an electromagnet) 6 for generating magnetism having a predetermined magnetic field strength. A Hall element 7 is provided at the center of the base 1 between the support portions 2a and 2b so as to face the magnet 6. The Hall element 7 is an element that converts the magnetic field strength of the magnet 6 into an on / off electric signal in a non-contact state and outputs the signal, and is characterized by being small, light, thin, inexpensive, and excellent in heat resistance. doing. In the Hall element 7,
A control unit 8 for controlling the pulse motor 4 is provided. The control unit 8 includes a pulse output unit 8a that outputs a pulse to be supplied to the pulse motor 4, and a counting unit (for example, a pulse counter) that counts the number of output pulses.
8b, monitoring means 8c for monitoring a change in the ON / OFF state of the Hall element, calculating means 8d for performing a predetermined calculation based on the count result of the pulse counter 8b and the monitoring result of the monitoring means 8c, and semiconductor for storing data It has a storage means 8e such as a memory, and the monitoring means 8c and the arithmetic means 8d are constituted by a central processing unit (CPU) or the like.

FIG. 2 is a diagram showing the positional relationship between the count values of the pulse counter 8b in the control unit 8 of FIG. The positioning method of the present embodiment using the positioning device of FIG. 1 will be described below with reference to FIG. In this positioning method, an example will be described in which the movable portion 5 is positioned at a center position between the support portions 2a and 2b. First, the pulse output means 8 a in the control unit 8 sends a pulse to the pulse motor 4 in a direction in which the movable unit 5 moves to the pulse motor 4 side. The number of pulses P0 transmitted at this time is the number of pulses corresponding to the movable part 5 moving by の of the maximum moving distance. While the movable section 5 is moving, the monitoring means 8c in the control section 8 monitors a change in the ON / OFF state of the Hall element 7. In the logic of this example, the state where the Hall element 7 detects the magnetic flux density by the magnet 6 is set to the ON state. If the Hall element 7 is turned on while the movable section 5 is moving, the transmission of the pulse to the pulse motor 4 is stopped when the Hall element 7 is turned on, and the pulse output means 8a newly outputs P0 + α. (However, + α is the magnetic sensing width of the Hall element 7)
Is transmitted to the pulse motor 4. At this point, the movable unit 5 stops at the position closest to the pulse motor 4 side. Here, the pulse counter 8b in the control unit 8 is reset.

Next, the pulse output means 8a in the control unit 8
Sends a pulse moving in a direction away from the pulse motor 4 to the pulse motor 4, and counts up the pulse counter 8b in accordance with the number of transmitted pulses. The monitoring unit 8c in the control unit 8 monitors a change in the state of the Hall element 7, and stores the value of the pulse counter 8b at the time of the first ON state in the storage unit 8e as Pon1. Further, the value of the pulse counter 8b when the Hall element 7 is turned off is stored in the storage means 8e as Poff1, and the transmission of the pulse to the pulse motor 4 is stopped. After the stop of the pulse transmission, the pulse output means 8a in the control section 8 sends the pulse number to the pulse motor 4 in order to move the movable section 5 to the position farthest from the pulse motor 4 (the right end in FIG. 1). A pulse of P0 + α is transmitted. After the transmission is completed, the control unit 8 resets the pulse counter 8b. After this reset, the pulse output means 8a in the control section 8 sends a pulse to the pulse motor 4 for moving the movable section 5 in a direction approaching the pulse motor 4 (to the left in FIG. 1). The pulse counter 8b counts down according to the number of pulses thus set.

The monitoring means 8c in the control unit 8 monitors a change in the state of the Hall element 7, and stores the value of the pulse counter 8b at the time of the first ON state in the storage means 8e as Pon2. After the storage, the value of the pulse counter 8b when the Hall element 7 is turned off is stored in the storage means 8e as Poff2, and the transmission of the pulse to the pulse motor 4 is stopped. Here, assuming that the case where the movable unit 5 moves rightward in FIG. 1 is a positive value and the case where the movable unit 5 moves leftward is a negative value, the control unit 8
Values Pon1, Poff1, Pon stored in the storage means 8e
The positional relationship between 2, Poff2 is as shown in FIG. Therefore, the pulse number PL corresponding to the entire stroke of the movable portion 5
Is PL = Pon1-Poff2-1 (= Poff1-Pon2-1), and the true center position in this positioning device is shown in FIG.
PL / 2. On the other hand, the pulse number PC corresponding to the center position detected by the Hall element 7 is given by: PC = (Pon1 + Poff1 −1) / 2 (relative value from the left end), and a deviation from the true center position in this positioning device occurs. The calculating unit 8d in the control unit 8 calculates the deviation amount P =
(PL / 2−PC) is obtained, and the shift amount P is stored in the storage unit 8e as a correction value.

At this time, since the movable portion 5 is stopped at the position Poff2 in FIG. 2, the pulse (P) corresponding to the correction value obtained here is sent to the pulse motor 4. Thereby, the movable section 5 is positioned at the true center position PL / 2, and the control section 8
Resets the pulse counter 8b and completes the positioning operation. When the movable portion 5 is to be positioned at the center position between the support portions 2a and 2b in the subsequent operation, since the correction value P has already been obtained, the correction value P is taken into consideration in the center position obtained by the Hall element 7. , And can be easily positioned at the true center position. Note that the minimum movable range in which the positioning mechanism using this embodiment can be incorporated is that the Hall element 7 only needs to change its state from off to on to off with the movement of the movable part 5. 7 is the magnetic sensing width + α. As described above, in the present embodiment, by using the position detection method using the small, light, and thin Hall element 7, even in a small device in which the positioning function cannot be incorporated in the conventional method, By simply securing a space for incorporating the Hall element 7 and the magnet 6, it is possible to add a positioning function at low cost.

Note that the present invention is not limited to the above embodiment, but can be applied to various modifications and uses. Examples of these modified examples and usage forms include, for example, the following (i),
There is something like (ii). (I) In the embodiment, in the device having a plurality of axes that move linearly, such as a mounter and a plotter, a method of positioning one of the axes at the center position has been described. By arranging, it is possible to increase the number of locations for positioning. When there are a plurality of axes that move linearly (that is, in the case of a device having a moving mechanism combining a plurality of axes), a Hall element 7 is added to each axis to perform positioning for each axis. It is possible to For example, when there are two axes that move linearly like an XY stage, if three Hall elements 7 are arranged on the X axis and three places on the Y axis, three positions can be positioned on each axis. If these are combined, it is possible to set 3 × 3 = 9 positioning positions. in this way,
The set number of positioning locations is the product of the number of Hall elements arranged on each axis. (Ii) Although the moving means of the movable part 5 is constituted by the screw 3 and the pulse motor 4, these may be constituted by other moving means. Although the magnet 6 is mounted on the movable part 5 and the Hall element 7 is mounted on the base 1, the Hall element 7 is mounted on the movable part 5 and the magnet 6 is mounted on the base 1. Almost the same operation and effect can be obtained.

[0012]

As described above in detail, according to the present invention, in an apparatus having a moving mechanism such as a mounter or a plotter, which has one or a plurality of linearly moving axes, a magnetic mechanism is provided. A positioning device including a generating unit, a Hall element, a control unit, and the like is provided, an actual measurement relation value between the pulse number and the moving distance of the movable unit is obtained, and this relation value and a theoretical relation value corresponding thereto are obtained. Is obtained as a correction value, and the number of pulses in consideration of the correction value is given to the moving means to move the movable portion to a predetermined position. In particular, the Hall element used in the present invention is small, light, and thin, and can be arranged with little influence on others, and has excellent characteristics in environmental resistance (wide specification temperature range). Therefore, it can be applied to a device with a small moving stroke in a space-saving manner and at a low cost, and can realize accurate non-contact positioning.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a positioning device using a Hall element used in an embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between count values of a control unit 8 of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2a, 2b Support part 3 Screw 4 Pulse motor 5 Movable part 6 Magnet 7 Hall element 8 Control part 8a Pulse output means 8b Pulse counter 8c Monitoring means 8d Calculation means 8e Storage means

Claims (1)

[Claims] A fixed part extending in a fixed direction; a movable part arranged to be movable in parallel with the fixed part; and a fixed part attached to one of the movable part and the fixed part, A magnetism generating unit for generating magnetism having a magnetic field strength; and a moving unit for moving the movable unit in parallel with the fixed unit in a direction corresponding to the polarity of a given pulse and a distance corresponding to the number of pulses. A Hall element that is attached to one of the fixed part and the movable part and that converts the magnetic field strength into an on / off electric signal and outputs the electric signal when passing near the magnetism generating means; Pulse output means for outputting the pulse to be given to the means, counting means for counting the number of output pulses, monitoring means for monitoring a change in the on / off state of the Hall element, arithmetic means, and storage means. A control unit comprising: a positioning device provided with the pulse output unit; the pulse output unit supplies the pulse to the moving unit to move the movable unit; and counts the number of pulses by the counting unit. On the basis of the counting result of the means and the monitoring result of the monitoring means, the arithmetic means determines an actually measured relation value between the number of pulses and the moving distance of the movable part, and this relation value and the theoretical relation corresponding thereto. The amount of deviation from the value is obtained as a correction value and stored in the storage unit, and the number of pulses in consideration of the correction value is given to the moving unit to move the movable unit to a predetermined position. Positioning method to be performed.