JPH072036B2 - Coil movable linear DC motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coil movable linear DC motor, and particularly to a coil suitable for a drive mechanism of a positioning device which has a relatively long movable range and which requires strict positioning accuracy. Movable linear DC motor.

[Conventional technology]

A conventional coil movable linear DC motor is disclosed in
As disclosed in Japanese Patent Laid-Open No. 58-49099, it is composed of a set of coils and an amplifier, and the coils are divided in order to make the force constant of the motor uniform over the entire stroke.

[Problems to be solved by the invention]

The above-mentioned prior art is insufficient in the following points to move a relatively long stroke at high speed and to perform highly accurate positioning at an arbitrary position in the stroke. For example, when considering a positioning device having a positioning range of 10 cm and a positioning accuracy of 0.1 μm, the positioning range for the positioning accuracy at this time is 10 ⁶ . When a servo system is configured in such a positioning device to perform positioning, in order to improve positioning controllability (positioning accuracy and positioning time), the rigidity of the servo system (motor thrust (N) / deviation amount (m)) ) May be increased within a stable range. However, if an attempt is made to generate sufficient thrust with a small amount of deviation to secure rigidity, in devices with a wide range such as the above example, the maximum thrust will be taken into consideration in consideration of the voltage saturation of the amplifier and the current limitation of the motor. There is a problem that can not be taken sufficiently. On the contrary, if the maximum thrust is set, there is a problem that the rigidity at the time of minute driving becomes insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a movable coil type linear DC motor suitable for a positioning device having a long moving distance and high positioning accuracy.

[Means for solving problems]

The above-mentioned object of the present invention is to divide the movable coil constituting the coil movable linear DC motor into a coil for high speed movement and a coil for minute positioning, and to use the same movable element (bobbin) for each.
It is achieved by connecting a control circuit for controlling the current supply amount of the coils based on the deviation amount between the target value and the displacement value to these coils.

[Action]

First, when high-speed and high-accuracy positioning can be performed, the amount of deviation between the target value and the current value is determined. When the amount of deviation becomes smaller than a certain value, the coil is switched to a minute positioning coil, the servo rigidity is increased, and the target value is settled in a short time.

Example of Invention

 An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an embodiment of a coil movable linear DC motor of the present invention, in which 1 is an outer yoke,
Reference numeral 2 is a center yoke, 3 is a side yoke, 4 is a permanent magnet provided inside the outer yoke 1, and 5 is a movable part made up of a coil and a bobbin that move along the center yoke. It is composed of three coils 51a, 51b, 51c and one set of three minute positioning coils 52a, 52b, 52c. b and c represent each phase of the three-phase coil. 6 is a field sensor for coil switching provided in the micropositioning coils 52a to 52c, 7 is a field sensor detection circuit, 8 is a three-phase coil switching circuit for high speed movement, 9 is a switching amplifier, and 10 is for micropositioning. 3 phase coil switching circuit, 11 is a linear amplifier, 12 is a switching circuit between a coil for high speed movement and a coil for fine positioning, 13 is a control circuit, 14 is a deviation signal generating circuit, 15 is a target value generating circuit, and 16 is a position. It is a detection circuit of a signal from a detector (not shown).

Next, the operation of one embodiment of the above-described linear motor of the present invention will be described.

The deviation e between the target value generation circuit 15 and the position detection circuit 16 is obtained from the deviation signal generation circuit 14, and the control circuit 13 stabilizes the deviation e. Also, the switching circuit 12 selects a coil for supplying a current according to the magnitude of the deviation, and the output of the control circuit 13 is the three-phase coil switching circuit 8 for high-speed movement or the three-phase coil for minute positioning. It is supplied to any of the coil switching circuits 10. When the deviation e is larger than a certain set value, a signal is supplied to the three-phase coil switching circuit 8 for high speed movement. In this circuit 8, the output of the field sensor 6 for coil switching is input to the circuit 8 through the field sensor detection circuit 7, and the coil to be energized is selected from among the three-phase coils according to the position of the coil. Next, the output signal of the circuit 8 is current-amplified by the switching amplifier 9 and then supplied to the coils 51a to 51c. The coils 51a to 51c are inserted into a gear cup in a magnetic circuit composed of the permanent magnet 4, the outer yoke 1 and the center yoke 2, and a thrust force is generated in the longitudinal direction by the interaction between the magnetic flux and the current passed through the coil to move. The part 5 is driven.

Next, when the movable part 5 including the coil moves and the deviation e becomes smaller than a certain set value, the coil switching circuit 12 supplies a signal to the three-phase coil switching circuit 10 for fine positioning,
After the current is amplified by the linear amplifier 11, the current is supplied to the micropositioning coils 52a to 52c. That is,
According to this embodiment, one of the coils 51a to 51c for high speed movement and the coils 52a to 52c for minute positioning are selected according to the deviation e, and a signal is supplied to the drive circuit corresponding to each of them. As a result, when the deviation e is large, a high thrust can be obtained to enable high-speed movement.
When becomes smaller, the thrust can be small, but the drive with high servo rigidity (thrust / deviation) can be realized, and the target value can be set quickly and precisely.

FIG. 2 shows another embodiment of the present invention, in which the same reference numerals as in FIG. 1 denote the same parts. This second
In the figure, 17 is a control circuit for high speed movement, 18 is a control circuit for minute positioning, and 19 is a switching circuit for high speed movement and minute positioning. In this embodiment, a control circuit corresponding to the coil is separately provided, and the control circuit for high speed movement 17
Is a control circuit that follows the shortest time control law, for example, and the fine positioning control circuit 18 is a position control system having a status feedback, for example. According to this embodiment, the controllability can be further enhanced by switching the control circuit.

Although the three-phase coil is used in the above embodiment,
Alternatively, a two-phase coil can be used.

FIG. 3 shows an embodiment of a rectangular coordinate type positioning unit using the coil movable linear DC motor of the present invention. In the figure, 101a and 101b are X-axis linear DC motors, 102 is a Y-axis linear DC motor, and 103 is an X for detecting the position in the X-axis direction.
Axis linear scale, 104 is Y for detecting the position in the Y-axis direction
The axis linear scales 105a and 105b are X-axis guide mechanisms, and in this figure, a movable portion surrounding the fixed portion having a cylindrical shape is supported by static pressure. Also, 106 is Y
The shaft guide mechanism has a structure in which a movable portion surrounding the two cylindrical fixed portions is supported by static pressure. Reference numeral 107 is a Y carriage that freely moves in the Y-axis direction along a fixed portion of the Y-axis guide mechanism 106, and 108 is an X-axis guide mechanism 105.
An X-carriage that freely moves in the X-axis direction along the fixed part of the X-axis guide mechanism 105, a Y-axis linear DC motor 102, a Y-axis linear scale 104, and an X-carriage 107. Here, the X-axis linear DC motor 101 and the Y-axis linear DC motor 102 are coil movable linear DC motors of the present invention, and the structure thereof is the same as that shown in FIG. 1 as the first embodiment of the present invention. It is the same. In the case of the X-axis linear DC motor 101, the movable part 5 including the coil and the bobbin in FIG. 1 is directly connected to the X-axis guide mechanism 105, and the X-carriage 108 is driven by energizing the coil. On the other hand, in the case of the Y-axis linear DC motor 102, the Y-carriage 107 is driven by being directly connected to the Y-axis guide mechanism 106 and energizing the coil.

The Cartesian positioning unit shown in FIG. 3 has a structure of non-contact direct drive by a linear DC motor and non-contact guide by static pressure guide. It is possible. For this reason, this unit is designed to mount electronic chip parts on the board,
It is used as a micron-order positioning device for assembly and assembly of optical fibers. The operation of this unit is composed of an operation 1 of taking out a component with a component supply tool and moving it to an object to be assembled and an operation 2 of precisely assembling the component. Here, in the operation 1, the moving distance is long, and high speed movement is required to shorten the tact time. Further, in the operation 2, precise positioning on the order of micron is required.
As described above, this unit requires two operations, that is, high speed movement and precise positioning. Therefore, by using the coil movable linear DC motor of the present invention as the drive mechanism of the present unit, the above-mentioned two operations can be shared by the plurality of coils and the control circuit, and each operation can be optimally performed. effective.

The movable coil linear DC motor of the present invention is the third
It can be applied to a positioning unit constituted by only one axis of the structure shown in the figure, and has the same effect.

〔The invention's effect〕

According to the present invention, one linear DC motor can have two functions of high speed movement and reduction positioning, for example. As a result, the coil movable linear DC motor of the present invention has an effect that the positioning performance can be increased and the positioning performance can be improved without changing the size of the motor.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the linear motor of the present invention, FIG. 2 is a diagram showing the configuration of another embodiment of the linear motor of the present invention, and FIG. 3 is a diagram of the linear motor device of the present invention. It is a structure of an Example. 1 ... Outer yoke, 2 ... Center yoke, 3 ... Side yoke, 4 ... Permanent magnet, 5 ... Moving part, 51a to 51c ...
... High-speed moving coil, 52a to 52c ... Fine positioning coil, 6 ... Coil switching field sensor, 7 ... Field sensor detection circuit, 8 ... High-speed moving three-phase coil switching circuit,
9: Switching amplifier, 10: 3 for fine positioning
Phase coil switching circuit, 11 …… Linear amplifier, 12 …… High-speed moving coil and minute positioning coil switching circuit, 17 ……
Control circuit for high speed movement, 18 ... Micro positioning control circuit.

Claims (3)

[Claims] 1. A permanent magnet, an outer yoke to which the permanent magnet is fixed, a center yoke provided at a distance from the permanent magnet, and a side yoke connecting the outer yoke and the center yoke. Coil movable linear direct current composed of a fixed portion, a bobbin that can freely move in a longitudinal direction in a gap between the permanent magnet and the center yoke, and a movable portion including a coil wound around the bobbin. In the motor, the coil is composed of a coil for high speed movement and a coil for minute positioning which are independent of each other, and the number of turns of the coil contributing to thrust is larger than that of the coil for minute positioning, Also, the high-speed moving coil outputs a control signal to the amplifier having a higher driving voltage than the minute positioning coil and the amplifier. The fine positioning coil has a smaller number of turns of the coil contributing to thrust than the high speed moving coil, and the fine positioning coil has a target position and the movable portion. Of the drive current with respect to the deviation from the current position of the high-speed moving coil is connected to an amplifier and a fine positioning control circuit for outputting a control signal to the amplifier. A means for selecting the two control circuits according to the deviation from the current position of the section,
A movable coil type linear DC motor characterized by the following. 2. The coil movable linear DC motor according to claim 1, wherein the high-speed moving coil and the minute positioning coil are three-phase coils. 3. The coil movable linear DC motor according to claim 1, wherein the high-speed moving coil and the minute positioning coil are two-phase coils.