JP2011043341A - Position detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detector which can reduce the effect of non-uniformity of a platen, a magnetic body characteristic, etc. <P>SOLUTION: The position detector includes a first core, a second core, a third core and a fourth core which are arranged in sequence in the direction of movement of a moving body at a pitch of 3/4 of the pitch of teeth of the platen. A first circuit formed by connecting in series a first winding and a third winding formed around on the first core and the third core respectively in a positive phase, and a second circuit formed by connecting in series a second winding and a fourth winding formed around on the second core and the fourth core respectively in the positive phase, are connected in parallel in a reverse phase to each other, and excitation voltage is given thereto. The voltage at a point of connection connecting the first winding and the third winding in the first circuit and the voltage at a point of connection connecting the second winding and the fourth winding in the second circuit are given to a detecting circuit respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is attached to a moving body that moves along a platen, the core facing the platen, a winding wound around the core, a power source that applies a high-frequency excitation voltage to the winding, and the winding And a detection circuit that detects a voltage generated in a line, and relates to a position detection device that detects a position of a moving body based on a voltage detected by the detection circuit.

  In a linear motor or a planar motor, a position detector that uses a resolver system is known as a position detection device used for positioning a slider. A resolver type position detection device detects a position by using a change in impedance of a magnetic circuit, and its configuration and principle are disclosed in Japanese Patent Laid-Open No. 2000-156127.

Japanese Patent Laid-Open No. 4-127891 JP 2000-156127 A

  In the resolver type position detection device, the position detection accuracy is affected by the degree of uniformity of the magnetic properties of the platen because of the characteristic of using the impedance of the magnetic circuit formed through the platen. However, in the case of a long linear motor or planar motor, when a motor stator core is created, it is divided into blocks of a predetermined length that are easy to manufacture and these are connected. Moreover, in order to ensure mechanical rigidity in the long motor stator core, the structure which fastens a motor stator core to a motor base with a fixing screw is employ | adopted. For this reason, the impedance of the magnetic circuit formed via the platen fluctuates when the magnetic circuit passes through the joints and fixing screws of the motor stator core, and becomes a different value from the other parts. Let

  In addition, the excitation frequency of the resolver part may be several tens of times higher than the frequency of the motor excitation current and one hundred times higher than the frequency of the motor excitation current in order to avoid interference of the motor excitation magnetic field or shorten the detection response time. On the other hand, the magnetic material used in the motor section increases the generated thrust, so a laminated structure such as a high-permeability silicon steel plate is common, and the magnetic permeability decreases and loss increases when excited at high frequencies. To do. Therefore, when a resolver is configured using this magnetic material, the modulation degree is lowered, leading to deterioration in detection accuracy.

  An object of the present invention is to provide a position detection device that can reduce the influence of platen non-uniformity, magnetic material characteristics, and the like.

A position detection device according to the present invention is attached to a moving body that moves along a platen, a core that faces the platen, a winding wound around the core, and a power source that applies a high-frequency excitation voltage to the winding And a detection circuit that detects a voltage generated in the winding, and a position detection device that detects the position of the moving body based on the voltage detected by the detection circuit, the core serving as the core A first core, a second core, a third core, and a fourth core that are arranged in order along the moving direction of the moving body at a pitch of 3/4 of a tooth pitch; and A first circuit formed by serially connecting a first winding and a third winding wound around the third core in a positive phase; and a second circuit and a fourth core, respectively. The wound second and fourth windings A second circuit that is connected in series in the positive phase, and a parallel connection in the opposite phase to each other, and the power source is connected to a circuit configured by connecting the first circuit and the second circuit in parallel in the opposite phase. A voltage at a connection point connecting the first winding and the third winding in the first circuit, and the second winding in the second circuit. And a voltage at a connection point connecting the fourth winding to the detection circuit, respectively.
According to this position detection device, the winding wound around the first core, the second core, the third core, and the fourth core due to a change in mutual inductance caused by the magnetic flux mainly passing through the surface layer portion of the tooth tip. Since the position detection is performed based on the voltage obtained by synthesizing the voltages generated in the platen, it is possible to reduce the influence of the platen non-uniformity and magnetic material characteristics due to the structure below the tooth tip.

A position detection device according to the present invention is attached to a moving body that moves along a platen, a core that faces the platen, a winding wound around the core, and a power source that applies a high-frequency excitation voltage to the winding And a detection circuit that detects a voltage generated in the winding, and a position detection device that detects a position of a moving body based on a voltage detected by the detection circuit, wherein the movement as the core A first core and a third core provided at positions having a phase difference of 90 degrees with respect to the pitch of the platen teeth with respect to the body movement direction, the first core and the third core; A first circuit is connected in series with the first winding and the third winding wound respectively in the positive phase, and the power supply is connected to the first circuit to generate the excitation voltage. In the first circuit The voltage at the connection point for connecting the serial first winding and a third winding, characterized in that applied to the detection circuit.
According to this position detection device, it is obtained by synthesizing the voltages generated in the windings wound around the first core and the third core due to the change in mutual inductance caused by the magnetic flux mainly passing through the surface layer portion of the tooth tip. Since the position is detected based on the measured voltage, the influence of the platen non-uniformity and magnetic properties due to the structure below the tooth tip can be reduced.

  The first core is divided into a plurality of divided cores, and the first winding is configured by serially connecting windings wound around the divided cores in a positive phase, and the plurality of divided cores are configured. The core may be arranged at the same phase position with respect to the teeth of the platen with respect to the moving direction of the moving body.

  The first core is divided into a plurality of divided cores, and the first winding is configured by serially connecting windings wound around the divided cores in a positive phase, and the plurality of divided cores are configured. The core may be disposed at a position slightly out of phase with respect to the teeth of the platen in the moving direction of the moving body.

  The plurality of divided cores may be arranged at positions shifted from each other in a direction orthogonal to a moving direction of the moving body.

  According to the position detection device of the present invention, based on the voltage obtained by synthesizing the voltages generated in the windings wound around the first core, the second core, the third core, and the fourth core. Since the position is detected, the influence of the non-uniformity of the platen and the magnetic material characteristics can be reduced.

  According to the position detection device of the present invention, the position detection is performed based on the voltage obtained by combining the voltages generated in the windings wound around the first core and the third core. The effects of uniformity and magnetic properties can be reduced.

The front view which shows the structure of a resolver. The top view which shows arrangement | positioning of a core. The figure which shows the connection method of a winding. The figure which shows the equivalent circuit of a position detection apparatus. The figure which shows the example which arrange | positions the core of each phase in the position which mutually shifted the phase slightly with respect to the comb tooth of the platen. The figure which shows a mode that the voltage of the four groups arrange | positioned mutually shifting phase was combined.

  Hereinafter, embodiments of the position detection device according to the present invention will be described.

  FIG. 1 is a front view showing the configuration of a resolver used in the position detection apparatus of this embodiment, and FIG. 2 is a plan view showing the arrangement of cores.

  In FIG. 1, the platen 3 constitutes a stator of a planar motor, and the resolver 10 is provided on a slider (not shown) that moves in the XY plane along the platen 3. The resolver 10 shown in FIG. 1 corresponds to a configuration for detecting the X coordinate of the slider.

  As shown in FIGS. 1 and 2, the platen 3 is provided with comb teeth 31 arranged in a matrix at a constant pitch in the XY plane.

  On the other hand, the resolver 10 includes cores 1, 1,... Arranged in a fixed pitch in the X direction and windings 2, 2,. Prepare. The cores 1, 1,... Are arranged in the X direction at a pitch of 3 / 4p, where p is the pitch of the comb teeth 31 of the platen 3. In FIG. 1, the positions (phases) of the respective cores with respect to the comb teeth 31 are shown as S0, C0, S1, and C1 in order. The positions of S0, C0, S1, and C1 are in a relationship that the phases are sequentially shifted by 90 degrees with respect to the comb teeth 31. As described above, the cores 1, 1,... Are repeatedly arranged at positions shifted in phase by 90 degrees with respect to the comb teeth 31. In FIG. 1 and FIG. 2, subscripts S0, C0, S1, and C1 indicating phases corresponding to the cores 1, 1,.

  As shown in FIG. 1, in the position detection device of the present embodiment, a magnetic circuit is configured through adjacent cores and the tips of comb teeth 31, and the impedance of the magnetic circuit is relative between the core and the comb teeth 31. Changes in accordance with the relative positional relationship, and the voltage generated in the winding also changes. For this reason, the position of the resolver 10 can be detected by capturing the voltage generated in the winding.

  As shown in FIG. 2, the cores 1, 1,... Are arranged so as to be shifted in the Y direction. This is for the purpose of providing a vernier effect, and can suppress measurement deviation when the resolver 10 moves in the Y direction.

  FIG. 3 is a diagram showing a winding connection method.

  As shown in FIG. 3, the windings 2, 2,... Of the cores 1, 1,. They are connected in series (in the direction in which the voltages are added). Similarly, the windings 1, 2,... Of the cores 1, 1,... At the position C0, the windings 2, 2,. The windings 2, 2, ... of the cores 1, 1, ... at the position of C1, are connected in series with each other in the positive phase. In this way, every four core windings are sequentially connected in series, so that the excitation voltage associated with the inductance change is averaged and the high frequency is suppressed.

  The material of the cores 1, 1,... Can be different from the magnetic material of the platen 3. The increase is reduced, and the inductance changes greatly depending on the positional relationship with the comb teeth 31, so that good sensor characteristics can be obtained.

  FIG. 4 is a diagram illustrating an equivalent circuit of the position detection device.

4, S0 winding L _S0 indicates windings 2 _S0 , 2 _S0 ,... Of cores 1 _S0 , 1 _S0,. Similarly, the C0 winding L _C0 is connected to the series-connected windings 2 _C0 , 2 _C0 ,..., And the S1 winding L _S1 is connected to the series-connected windings 2 _S1 , 2 _S1 ,. Winding L _C1 indicates windings 2 _C1 , 2 _C1 ,... Connected in series.

As shown in FIG. 4, the S0 winding L _S0 and the S1 winding L _S1 are connected in series in the positive phase to constitute a first circuit. Further, the C0 winding L _C0 and the C1 winding L _C1 are connected in series in the positive phase to form a second circuit.

  Further, the first circuit and the second circuit are connected in parallel to each other, and a power supply 4 for generating a high-frequency excitation voltage is connected to both ends thereof. At this time, as shown in FIG. 4, in the first circuit and the second circuit, the windings of the respective circuits are in the opposite phase (in the direction in which the voltages cancel each other when the same inductance change is given). ) Connected in parallel.

The voltage vs at the midpoint between the S0 winding L _S0 and the S1 winding L _S1 and the voltage vc at the midpoint between the C0 winding L _C0 and the C1 winding L _C1 are connected to the detection circuit 5, respectively.

The self-inductance of windings L _S0 , L _S1 , L _C0 , and L _C1 in FIG. 4 is L, and the mutual inductance between winding L _S0 and winding L _C0 due to magnetic coupling between adjacent cores is M00. The mutual inductance between the winding L _C0 and the winding L _S1 is M10, the mutual inductance between the winding L _S1 and the winding L _C1 is M11, and the mutual inductance between the winding L _C1 and the winding L _S0 is When M01 is set and the moving distance of the resolver 10 is X, the high frequency is suppressed.

It becomes.

  Also,

Therefore, the position X of the resolver 10 can be obtained from the change in mutual inductance by obtaining θ from the amplitudes As and Ac by tan ⁻¹ calculation. Thus, in the position detection device of the present embodiment, position detection can be performed using magnetic coupling between cores adjacent to each other through a space.

  FIG. 5 is a diagram illustrating an example in which the cores of the respective phases S0, C0, S1, and C1 are arranged at positions slightly shifted from each other with respect to the comb teeth 31 of the platen 2. In the example of FIG. 5, by reducing the pitch of each phase by p / n, the phase of the core in the X direction is slightly shifted to provide a vernier effect and suppress harmonics of measurement errors. be able to.

  FIG. 6 shows a state in which voltages of four groups (groups A to D) arranged with phases shifted from each other are synthesized. As shown as “average of each group” in FIG. 6, a voltage signal in which a high frequency component is suppressed is obtained by serially connecting windings of phases (S0, C0, S1, C1) belonging to these groups. Can do.

  As described above, according to the position detection device of the present invention, position detection is performed based on the voltage obtained by synthesizing voltages generated in windings wound around a plurality of cores provided at different positions. As a result, the influence of the non-uniformity of the platen and the magnetic properties can be reduced. Further, since the magnetic field circuit is formed only through the platen tooth tip, it is not easily affected by the non-uniformity of the magnetic properties derived from the structure of the platen, and highly accurate position detection is possible.

  In the above embodiment, an example in which the stator of the planar motor is used as the platen has been described. However, a platen for position detection by a resolver may be provided separately from the stator. Further, the position detection device of the present invention can be applied to position detection not only in a planar motor but also in a linear motor.

  The scope of application of the present invention is not limited to the above embodiment. The present invention is attached to a moving body that moves along a platen, the core facing the platen, a winding wound around the core, a power source that applies a high-frequency excitation voltage to the winding, and the winding And a detection circuit that detects a voltage generated in the line, and can be widely applied to a position detection device that detects the position of the moving body based on the voltage detected by the detection circuit.

1 core (split core)
2 Winding 3 Platen 4 Power supply 5 Detection circuit

Claims (5)

A core attached to a moving body that moves along the platen, and facing the platen;
A winding wound around the core;
A power supply for applying a high frequency excitation voltage to the winding;
A detection circuit for detecting a voltage generated in the winding;
A position detection device for detecting the position of the moving body based on the voltage detected by the detection circuit,
The core includes a first core, a second core, a third core, and a fourth core arranged in order along the moving direction of the moving body at a pitch of 3/4 of the pitch of the platen teeth,
A first circuit formed by serially connecting a first winding and a third winding wound around the first core and the third core in a positive phase; the second core; A second circuit formed by connecting the second winding and the fourth winding wound around the fourth core in series in the normal phase, and in parallel in the opposite phase to each other,
Connecting the power source to a circuit configured by connecting the first circuit and the second circuit in parallel in opposite phases to provide the excitation voltage;
A voltage at a connection point connecting the first winding and the third winding in the first circuit; and the second winding and the fourth winding in the second circuit. A position detecting device, wherein a voltage at a connection point to be connected is supplied to the detection circuit. A core attached to a moving body that moves along the platen, and facing the platen;
A winding wound around the core;
A power supply for applying a high frequency excitation voltage to the winding;
A detection circuit for detecting a voltage generated in the winding;
A position detection device for detecting the position of the moving body based on the voltage detected by the detection circuit,
The core includes a first core and a third core provided at positions having a phase difference of 180 degrees with respect to the pitch of the platen teeth with respect to the moving direction of the moving body,
A first circuit is configured by serially connecting a first winding and a third winding wound around the first core and the third core in a positive phase,
Connecting the power source to the first circuit to provide the excitation voltage;
A position detection device that applies a voltage at a connection point connecting the first winding and the third winding in the first circuit to the detection circuit. The first core is divided into a plurality of divided cores, and the first winding is configured by serially connecting the windings wound around the divided cores in a positive phase,
The position detection device according to claim 1, wherein the plurality of divided cores are arranged at the same phase with respect to the teeth of the platen in the moving direction of the moving body. The first core is divided into a plurality of divided cores, and the first winding is configured by serially connecting the windings wound around the divided cores in a positive phase,
The position detection device according to claim 1, wherein the plurality of divided cores are arranged at positions slightly out of phase with respect to the teeth of the platen with respect to the moving direction of the moving body. 5. The position detection device according to claim 3, wherein the plurality of divided cores are arranged at positions shifted from each other in a direction orthogonal to a moving direction of the moving body.